WorldWideScience

Sample records for biphasic osteochondral implant

  1. Osteochondral tissue engineering with biphasic scaffold: current strategies and techniques.

    Science.gov (United States)

    Shimomura, Kazunori; Moriguchi, Yu; Murawski, Christopher D; Yoshikawa, Hideki; Nakamura, Norimasa

    2014-10-01

    The management of osteoarthritis (OA) remains challenging and controversial. Although several clinical options exist for the treatment of OA, regeneration of the damaged articular cartilage has proved difficult due to the limited healing capacity. With the advancements in tissue engineering and cell-based technologies over the past decade, new therapeutic options for patients with osteochondral lesions potentially exist. This review will focus on the feasibility of tissue-engineered biphasic scaffolds, which can mimic the native osteochondral complex, for osteochondral repair and highlight the recent development of these techniques toward tissue regeneration. Moreover, basic anatomy, strategy for osteochondral repair, the design and fabrication methods of scaffolds, as well as the choice of cells, growth factor, and materials will be discussed. Specifically, we focus on the latest preclinical animal studies using large animals and clinical trials with high clinical relevance. In turn, this will facilitate an understanding of the latest trends in osteochondral repair and contribute to the future application of such clinical therapies in patients with OA.

  2. A biphasic scaffold based on silk and bioactive ceramic with stratified properties for osteochondral tissue regeneration.

    Science.gov (United States)

    Li, Jiao Jiao; Kim, Kyungsook; Roohani-Esfahani, Seyed-Iman; Guo, Jin; Kaplan, David L; Zreiqat, Hala

    2015-07-14

    Significant clinical challenges encountered in the effective long-term treatment of osteochondral defects have inspired advancements in scaffold-based tissue engineering techniques to aid repair and regeneration. This study reports the development of a biphasic scaffold produced via a rational combination of silk fibroin and bioactive ceramic with stratified properties to satisfy the complex and diverse regenerative requirements of osteochondral tissue. Structural examination showed that the biphasic scaffold contained two phases with different pore morphologies to match the cartilage and bone segments of osteochondral tissue, which were joined at a continuous interface. Mechanical assessment showed that the two phases of the biphasic scaffold imitated the load-bearing behaviour of native osteochondral tissue and matched its compressive properties. In vitro testing showed that different compositions in the two phases of the biphasic scaffold could direct the preferential differentiation of human mesenchymal stem cells towards the chondrogenic or osteogenic lineage. By featuring simple and reproducible fabrication and a well-integrated interface, the biphasic scaffold strategy established in this study circumvented the common problems experienced with integrated scaffold designs and could provide an effective approach for the regeneration of osteochondral tissue.

  3. Mechanical and morphological evaluation of osteochondral implants in dogs.

    Science.gov (United States)

    Bavaresco, Vanessa P; Garrido, Luiz; Batista, Nilza A; Malmonge, Sônia M; Belangero, William D

    2008-04-01

    The mechanical behavior of osteochondral defects was evaluated in this study with the intention of developing alternative procedures. Cylindrical pins (5.00 mm in diameter and in height) made of pHEMA hydrogel covered ultra-high molecular weight polyethylene (UHMWPE) or beta-tricalcium phosphate (beta-TCP) matrix were used. Ostoechondral defects were caused in the knees of adult dogs and the evaluation was carried out after a 9-month follow-up period. The mechanical behavior of the implants was evaluated by means of an indentation creep test that showed that the UHMWPE matrix maintained its viscoelastic behavior even after follow-up time, while the beta-TCP matrix osteochondral implants presented significant alterations. It is believed that the beta-TCP osteochondral implants were unable to withstand the load applied, causing an increase of complacency when compared to the UHMWPE osteochondral implants. Based on micro and macroscopic analysis, no significant wear was observed in either of the osteochondral implants when compared to the controls. However, morphological alterations, with fragmentation indices in the patella, were observed either due to friction with the hydrogel in the first postoperative months or due to forming of a dense conjunctive tissue. This wear mechanism caused on the counterface of the implant (patella) was observed, notwithstanding the osteochondral implant studied.

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

    Science.gov (United States)

    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.

  5. Evaluation of an extracellular matrix-derived acellular biphasic scaffold/cell construct in the repair of a large articular high-load-bearing osteochondral defect in a canine model

    Institute of Scientific and Technical Information of China (English)

    YANG Qiang; MA Xin-long; HU Yong-cheng; XU Bao-shan; PENG Jiang; LU Shi-bi; GUO Quan-yi; ZHAO Bin; ZHANG Li; WANG Ai-yuan; XU Weng-jing; XIA Qun

    2011-01-01

    Background Osteochondral lesion repair is a challenging area of orthopedic surgery.Here we aimed to develop an extraceliular matrix-derived,integrated,biphasic scaffold and to investigate the regeneration potential of the scaffold loaded with chondrogenically-induced bone marrow-derived mesenchymal stem cells (BMSCs) in the repair of a large,high-load-bearing,osteochondral defect in a canine model.Methods The biphasic scaffolds were fabricated by combining a decellularization procedure with a freeze-drying technique and characterized by scanning electron microscopy (SEM) and micro-computed tomography (micro-CT).Osteochondral constructs were fabricated in vitro using chondrogenically-induced BMSCs and a biphasic scaffold,then assessed by SEM for cell attachment.Osteochondral defects (4.2 mm (diameter) x 6 mm (depth)) were created in canine femoral condyles and treated with a construct of the biphasic scaffold/chondrogenically-induced BMSCs or with a cell-free scaffold (control group).The repaired defects were evaluated for gross morphology and by histological,biochemical,biomechanical and micro-CT analyses at 3 and 6 months post-implantation.Results The osteochondral defects of the experimental group showed better repair than those of the control group.Statistical analysis demonstrated that the macroscopic and histologic grading scores of the experimental group were always higher than those of the control group,and that the scores for the experimental group at 6 months were significantly higher than those at 3 months.The cartilage stiffness in the experimental group (6 months) was (6.95±0.79)N/mm,70.77% of normal cartilage; osteochondral bone stiffness in the experimental group was (158.16±94.30) N/mm,74.95% of normal tissue; glycosaminoglycan content of tissue-engineered neocartilage was (218±21.6) μg/mg (dry weight),84.82% of native cartilage.Micro-CT analysis of the subchondral bone showed mature trabecular bone regularly formed at 3 and 6 months

  6. The Augmentation of a Collagen/Glycosaminoglycan Biphasic Osteochondral Scaffold with Platelet-Rich Plasma and Concentrated Bone Marrow Aspirate for Osteochondral Defect Repair in Sheep

    Science.gov (United States)

    Henson, Frances; Skelton, Carrie; Herrera, Emilio; Brooks, Roger; Fortier, Lisa A.; Rushton, Neil

    2012-01-01

    Objective: This study investigates the combination of platelet-rich plasma (PRP) or concentrated bone marrow aspirate (CBMA) with a biphasic collagen/glycosaminoglycan (GAG) osteochondral scaffold for the treatment of osteochondral defects in sheep. Design: Acute osteochondral defects were created in the medial femoral condyle (MFC) and the lateral trochlea sulcus (LTS) of 24 sheep (n = 6). Defects were left empty or filled with a 6 × 6-mm scaffold, either on its own or in combination with PRP or CBMA. Outcome measures at 6 months included mechanical testing, International Cartilage Repair Society (ICRS) repair score, modified O’Driscoll histology score, qualitative histology, and immunohistochemistry for type I, II, and VI collagen. Results: No differences in mechanical properties, ICRS repair score, or modified O’Driscoll score were detected between the 4 groups. However, qualitative assessments of the histological architecture, Safranin O content, and collagen immunohistochemistry indicated that in the PRP/scaffold groups, there was a more hyaline cartilage–like tissue repair. In addition, the addition of CBMA and PRP to the scaffold reduced cyst formation in the subchondral bone of healed lesions. Conclusion: There was more hyaline cartilage–like tissue formed in the PRP/scaffold group and less subchondral cystic lesion formation in the CBMA and PRP/scaffold groups, although there were no quantitative differences in the repair tissue formed. PMID:26069645

  7. 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

    Full Text Available This study aims to prepare biphasic osteochondral scaffolds based on seamless joining of sintered polymer and polymer/ceramic microspheres for co-culture of chondrocytes and bone marrow stem cells (BMSCs. Poly(lactide-co-glycolide (PLGA microspheres and 10% nanohydroxyapatite (nHAP-incorporated PLGA (PGA/nHAP microspheres were prepared through the oil-in-water precipitation method. Virgin (V and composite (C scaffolds were prepared from 250–500 µm PLGA and PLGA/nHAP microspheres, respectively, while osteochondral (OC scaffolds were fabricated through the combination of V and C scaffolds. Physico-chemical properties of scaffolds were characterized through microscopic-spectroscopic evaluations. The effect of nHAP in scaffolds was investigated through thermogravimetric analysis and mechanical testing, while surface hydrophobicity was tested through contact angle measurements. Rabbit chondrocytes and BMSCs were used for cell culture, and cell morphology and proliferation were determined from SEM and DNA assays. Alizarin red and Alcian blue stains were used to identify the in vitro bone and cartilage tissue-specific regeneration, while cetylpyridinium chloride was used to quantitatively estimate calcium in mineralized bone. For co-culture in OC scaffolds, BMSCs were first seeded in the bone part of the scaffold and cultured in osteogenic medium, followed by seeding chondrocytes in the cartilage part, and cultured in chondrocyte medium. High cell viability was confirmed from the Live/Dead assays. Actin cytoskeleton organization obtained by DAPI-phalloidin staining revealed proper organization of chondrocytes and BMSCs in OC scaffolds. Immunofluorescent staining of bone (type I collagen and osteocalcin (OCN and cartilage marker proteins (type II collagen (COL II confirmed cellular behavior of osteoblasts and chondrocytes in vitro. Using an ectopic osteochondral defect model by subcutaneous implantation of co-cultured OC scaffolds in nude mice

  8. Novel metallic implantation technique for osteochondral defects of the medial talar dome. A cadaver study

    NARCIS (Netherlands)

    C.J.A. van Bergen; M. Zengerink; L. Blankevoort; M.N. van Sterkenburg; J. van Oldenrijk; C.N. van Dijk

    2010-01-01

    BACKGROUND AND PURPOSE: A metallic inlay implant (HemiCAP) with 15 offset sizes has been developed for the treatment of localized osteochondral defects of the medial talar dome. The aim of this study was to test the following hypotheses: (1) a matching offset size is available for each talus, (2) th

  9. A New Biphasic Dicalcium Silicate Bone Cement Implant

    Directory of Open Access Journals (Sweden)

    Fausto Zuleta

    2017-07-01

    Full Text Available This study aimed to investigate the processing parameters and biocompatibility of a novel biphasic dicalcium silicate (C2S cement. Biphasic α´L + β-C2Sss was synthesized by solid-state processing, and was used as a raw material to prepare the cement. In vitro bioactivity and biocompatibility studies were assessed by soaking the cement samples in simulated body fluid (SBF and human adipose stem cell cultures. Two critical-sized defects of 6 mm Ø were created in 15 NZ tibias. A porous cement made of the high temperature forms of C2S, with a low phosphorous substitution level, was produced. An apatite-like layer covered the cement’s surface after soaking in SBF. The cell attachment test showed that α´L + β-C2Sss supported cells sticking and spreading after 24 h of culture. The cement paste (55.86 ± 0.23 obtained higher bone-to-implant contact (BIC percentage values (better quality, closer contact in the histomorphometric analysis, and defect closure was significant compared to the control group (plastic. The residual material volume of the porous cement was 35.42 ± 2.08% of the initial value. The highest BIC and bone formation percentages were obtained on day 60. These results suggest that the cement paste is advantageous for initial bone regeneration.

  10. Treatment of osteochondral defects in the rabbit's knee joint by implantation of allogeneic mesenchymal stem cells in fibrin clots.

    Science.gov (United States)

    Berninger, Markus T; Wexel, Gabriele; Rummeny, Ernst J; Imhoff, Andreas B; Anton, Martina; Henning, Tobias D; Vogt, Stephan

    2013-05-21

    The treatment of osteochondral articular defects has been challenging physicians for many years. The better understanding of interactions of articular cartilage and subchondral bone in recent years led to increased attention to restoration of the entire osteochondral unit. In comparison to chondral lesions the regeneration of osteochondral defects is much more complex and a far greater surgical and therapeutic challenge. The damaged tissue does not only include the superficial cartilage layer but also the subchondral bone. For deep, osteochondral damage, as it occurs for example with osteochondrosis dissecans, the full thickness of the defect needs to be replaced to restore the joint surface (1). Eligible therapeutic procedures have to consider these two different tissues with their different intrinsic healing potential (2). In the last decades, several surgical treatment options have emerged and have already been clinically established (3-6). Autologous or allogeneic osteochondral transplants consist of articular cartilage and subchondral bone and allow the replacement of the entire osteochondral unit. The defects are filled with cylindrical osteochondral grafts that aim to provide a congruent hyaline cartilage covered surface (3,7,8). Disadvantages are the limited amount of available grafts, donor site morbidity (for autologous transplants) and the incongruence of the surface; thereby the application of this method is especially limited for large defects. New approaches in the field of tissue engineering opened up promising possibilities for regenerative osteochondral therapy. The implantation of autologous chondrocytes marked the first cell based biological approach for the treatment of full-thickness cartilage lesions and is now worldwide established with good clinical results even 10 to 20 years after implantation (9,10). However, to date, this technique is not suitable for the treatment of all types of lesions such as deep defects involving the subchondral

  11. In vivo effects of isolated implantation of salmon-derived crosslinked atelocollagen sponge into an osteochondral defect.

    Science.gov (United States)

    Kawaguchi, Yasuyuki; Kondo, Eiji; Kitamura, Nobuto; Arakaki, Kazunobu; Tanaka, Yasuhito; Munekata, Masanobu; Nagai, Nobuhiro; Yasuda, Kazunori

    2011-02-01

    We have developed crosslinked salmon-derived atelocollagen (SC) sponge, which has a denaturation temperature of 47°C. Sixty-four knees of 32 mature rabbits were randomly divided into 4 groups after creating an osteochondral defect in the femoral trochlea. Defects in Groups I, II, and III were filled with the crosslinked SC sponge, the crosslinked porcine collagen (PC) sponge, and the non-crosslinked PC sponge, respectively. In Group IV, defects were left untreated as the control. At 12 weeks after implantation, the histological score showed that Group I was significantly greater than Groups III (P = 0.0196) and IV (P = 0.0021). In addition, gene expression of type-2 collagen, aggrecan, and SOX9 was the greatest in Group I at 12 weeks. The fundamental in vivo properties of the crosslinked SC sponge showed that this is a promising biomaterial, specifically as a scaffold for cartilage tissue engineering.

  12. 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

    , 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...

  13. 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 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 implant for reconstruction of a focal cartilage defect demonstrated effective implant fixation and superior in vivo response compared to an identical Co-Cr alloy implant.

  14. The promotion of osteochondral repair by combined intra-articular injection of parathyroid hormone-related protein and implantation of a bi-layer collagen-silk scaffold.

    Science.gov (United States)

    Zhang, Wei; Chen, Jialin; Tao, Jiadong; Hu, Changchang; Chen, Longkun; Zhao, Hongshi; Xu, Guowei; Heng, Boon C; Ouyang, Hong Wei

    2013-08-01

    The repair of osteochondral defects can be enhanced with scaffolds but is often accompanied with undesirable terminal differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Parathyroid hormone-related protein (PTHrP) has been shown to inhibit aberrant differentiation, but administration at inappropriate time points would have adverse effects on chondrogenesis. This study aims to develop an effective tissue engineering strategy by combining PTHrP and collagen-silk scaffold for osteochondral defect repair. The underlying mechanisms of the synergistic effect of combining PTHrP administration with collagen-silk scaffold implantation for rabbit knee joint osteochondral defect repair were investigated. In vitro studies showed that PTHrP treatment significantly reduced Alizarin Red staining and expression of terminal differentiation-related markers. This is achieved in part through blocking activation of the canonical Wnt/β-catenin signaling pathway. For the in vivo repair study, intra-articular injection of PTHrP was carried out at three different time windows (4-6, 7-9 and 10-12 weeks) together with implantation of a bi-layer collagen-silk scaffold. Defects treated with PTHrP at the 4-6 weeks time window exhibited better regeneration (reconstitution of cartilage and subchondral bone) with minimal terminal differentiation (hypertrophy, ossification and matrix degradation), as well as enhanced chondrogenesis (cell shape, Col2 and GAG accumulation) compared with treatment at other time windows. Furthermore, the timing of PTHrP administration also influenced PTHrP receptor expression, thus affecting the treatment outcome. Our results demonstrated that intra-articular injection of PTHrP at 4-6 weeks post-injury together with collagen-silk scaffold implantation is an effective strategy for inhibiting terminal differentiation and enhancing chondrogenesis, thus improving cartilage repair and regeneration in a rabbit model. Copyright © 2013 Elsevier Ltd. All

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

    Science.gov (United States)

    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. PMID:25177697

  16. 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.

  17. 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.

  18. Intra-articular administration of hyaluronic acid increases the volume of the hyaline cartilage regenerated in a large osteochondral defect by implantation of a double-network gel.

    Science.gov (United States)

    Fukui, Takaaki; Kitamura, Nobuto; Kurokawa, Takayuki; Yokota, Masashi; Kondo, Eiji; Gong, Jian Ping; Yasuda, Kazunori

    2014-04-01

    Implantation of PAMPS/PDMAAm double-network (DN) gel can induce hyaline cartilage regeneration in the osteochondral defect. However, it is a problem that the volume of the regenerated cartilage tissue is gradually reduced at 12 weeks. This study investigated whether intra-articular administration of hyaluronic acid (HA) increases the volume of the cartilage regenerated with the DN gel at 12 weeks. A total of 48 rabbits were used in this study. A cylindrical osteochondral defect created in the bilateral femoral trochlea was treated with DN gel (Group DN) or left without any implantation (Group C). In both Groups, we injected 1.0 mL of HA in the left knee, and 1.0 mL of saline solution in the right knee. Quantitative histological evaluations were performed at 2, 4, and 12 weeks, and PCR analysis was performed at 2 and 4 weeks after surgery. In Group DN, the proteoglycan-rich area was significantly greater in the HA-injected knees than in the saline-injected knees at 12 weeks (P = 0.0247), and expression of type 2 collagen, aggrecan, and Sox9 mRNAs was significantly greater in the HA-injected knees than in the saline-injected knees at 2 weeks (P = 0.0475, P = 0.0257, P = 0.0222, respectively). The intra-articular administration of HA significantly enhanced these gene expression at 2 weeks and significantly increased the volume of the hyaline cartilage regenerated by implantation of a DN gel at 12 weeks. This information is important to develop an additional method to increase the volume of the hyaline cartilage tissue in a potential cartilage regeneration strategy using the DN gel.

  19. Microdrilled cartilage defects treated with thrombin-solidified chitosan/blood implant regenerate a more hyaline, stable, and structurally integrated osteochondral unit compared to drilled controls.

    Science.gov (United States)

    Marchand, Catherine; Chen, Gaoping; Tran-Khanh, Nicolas; Sun, Jun; Chen, Hongmei; Buschmann, Michael D; Hoemann, Caroline D

    2012-03-01

    controls, chitosan implants solidified with thrombin elicited a more hyaline and structurally integrated osteochondral unit, features needed for long-term durability.

  20. Decontamination Using a Desiccant with Air Powder Abrasion Followed by Biphasic Calcium Sulfate Grafting: A New Treatment for Peri-Implantitis

    Directory of Open Access Journals (Sweden)

    Giorgio Lombardo

    2015-01-01

    Full Text Available Peri-implantitis is characterized by inflammation and crestal bone loss in the tissues surrounding implants. Contamination by deleterious bacteria in the peri-implant microenvironment is believed to be a major factor in the etiology of peri-implantitis. Prior to any therapeutic regenerative treatment, adequate decontamination of the peri-implant microenvironment must occur. Herein we present a novel approach to the treatment of peri-implantitis that incorporates the use of a topical desiccant (HYBENX, along with air powder abrasives as a means of decontamination, followed by the application of biphasic calcium sulfate combined with inorganic bovine bone material to augment the intrabony defect. We highlight the case of a 62-year-old man presenting peri-implantitis at two neighboring implants in positions 12 and 13, who underwent access flap surgery, followed by our procedure. After an uneventful 2-year healing period, both implants showed an absence of bleeding on probing, near complete regeneration of the missing bone, probing pocket depth reduction, and clinical attachment gain. While we observed a slight mucosal recession, there was no reduction in keratinized tissue. Based on the results described within, we conclude that the use of HYBENX and air powder abrasives, followed by bone defect grafting, represents a viable option in the treatment of peri-implantitis.

  1. Osteochondritis Dissecans (OCD)

    Science.gov (United States)

    ... mice, motion, necrosis, osteochondritis, osteochondroses, pain, repetitive, sticking, stress, subchondral Family Health, Kids and Teens, Men September 2000 Copyright © American Academy of Family ...

  2. Influence of the gel thickness on in vivo hyaline cartilage regeneration induced by double-network gel implanted at the bottom of a large osteochondral defect: short-term results.

    Science.gov (United States)

    Matsuda, Hidetoshi; Kitamura, Nobuto; Kurokawa, Takayuki; Arakaki, Kazunobu; Gong, Jian Ping; Kanaya, Fuminori; Yasuda, Kazunori

    2013-01-31

    A double-network (DN) gel, which is composed of poly(2-acrylamido-2-methylpropanesulfonic acid) and poly(N,N'-dimethyl acrylamide), can induce hyaline cartilage regeneration in vivo in a large osteochondral defect. The purpose of this study was to clarify the influence of the thickness of the implanted DN gel on the induction ability of hyaline cartilage regeneration. Thirty-eight mature rabbits were used in this study. We created an osteochondral defect having a diameter of 4.3-mm in the patellofemoral joint. The knees were randomly divided into 4 groups (Group I: 0.5-mm thick gel, Group II: 1.0-mm thick gel, Group III: 5.0-mm thick gel, and Group IV: untreated control). Animals in each group were further divided into 3 sub-groups depending on the gel implant position (2.0-, 3.0-, or 4.0-mm depth from the articular surface) in the defect. The regenerated tissues were evaluated with the Wayne's gross and histological grading scales and real time PCR analysis of the cartilage marker genes at 4 weeks. According to the total Wayne's score, when the depth of the final vacant space was set at 2.0 mm, the scores in Groups I, II, and III were significantly greater than that Group IV (phyaline cartilage regeneration as the 5.0-mm thick DN gel plug. However, the induction ability of the 0.5-mm thick sheet was significantly lower when compared with the 1.0-mm thick gel sheet. The 1.0-mm DN gel sheet is a promising device to establish a cell-free cartilage regeneration strategy that minimizes bone loss from the gel implantation.

  3. Influence of the gel thickness on in vivo hyaline cartilage regeneration induced by double-network gel implanted at the bottom of a large osteochondral defect: Short-term results

    Directory of Open Access Journals (Sweden)

    Matsuda Hidetoshi

    2013-01-01

    Full Text Available Abstract Background A double-network (DN gel, which is composed of poly(2-acrylamido-2-methylpropanesulfonic acid and poly(N,N’-dimethyl acrylamide, can induce hyaline cartilage regeneration in vivo in a large osteochondral defect. The purpose of this study was to clarify the influence of the thickness of the implanted DN gel on the induction ability of hyaline cartilage regeneration. Methods Thirty-eight mature rabbits were used in this study. We created an osteochondral defect having a diameter of 4.3-mm in the patellofemoral joint. The knees were randomly divided into 4 groups (Group I: 0.5-mm thick gel, Group II: 1.0-mm thick gel, Group III: 5.0-mm thick gel, and Group IV: untreated control. Animals in each group were further divided into 3 sub-groups depending on the gel implant position (2.0-, 3.0-, or 4.0-mm depth from the articular surface in the defect. The regenerated tissues were evaluated with the Wayne’s gross and histological grading scales and real time PCR analysis of the cartilage marker genes at 4 weeks. Results According to the total Wayne’s score, when the depth of the final vacant space was set at 2.0 mm, the scores in Groups I, II, and III were significantly greater than that Group IV (p  Conclusions The 1.0-mm thick DN gel sheet had the same ability to induce hyaline cartilage regeneration as the 5.0-mm thick DN gel plug. However, the induction ability of the 0.5-mm thick sheet was significantly lower when compared with the 1.0-mm thick gel sheet. The 1.0-mm DN gel sheet is a promising device to establish a cell-free cartilage regeneration strategy that minimizes bone loss from the gel implantation.

  4. Bone marrow aspiration concentrate and platelet rich plasma for osteochondral repair in a porcine osteochondral defect model.

    Directory of Open Access Journals (Sweden)

    Marcel Betsch

    Full Text Available BACKGROUND: Bone marrow aspiration concentrate (BMAC may possess a high potency for cartilage and osseous defect healing because it contains stem cells and multiple growth factors. Alternatively, platelet rich plasma (PRP, which contains a cocktail of multiple growth factors released from enriched activated thrombocytes may potentially stimulate the mesenchymal stem cells (MSCs in bone marrow to proliferate and differentiate. METHODS: A critical size osteochondral defect (10×6 mm in both medial femoral condyles was created in 14 Goettinger mini-pigs. All animals were randomized into the following four groups: biphasic scaffold alone (TRUFIT BGS, Smith & Nephew, USA, scaffold with PRP, scaffold with BMAC and scaffold in combination with BMAC and PRP. After 26 weeks all animals were euthanized and histological slides were cut, stained and evaluated using a histological score and immunohistochemistry. RESULTS: The thrombocyte number was significantly increased (p = 0.049 in PRP compared to whole blood. In addition the concentration of the measured growth factors in PRP such as BMP-2, BMP-7, VEGF, TGF-β1 and PDGF were significantly increased when compared to whole blood (p<0.05. In the defects of the therapy groups areas of chondrogenic tissue were present, which stained blue with toluidine blue and positively for collagen type II. Adding BMAC or PRP in a biphasic scaffold led to a significant improvement of the histological score compared to the control group, but the combination of BMAC and PRP did not further enhance the histological score. CONCLUSIONS: The clinical application of BMAC or PRP in osteochondral defect healing is attractive because of their autologous origin and cost-effectiveness. Adding either PRP or BMAC to a biphasic scaffold led to a significantly better healing of osteochondral defects compared with the control group. However, the combination of both therapies did not further enhance healing.

  5. Pediatric Knee Osteochondritis Dissecans Lesions.

    Science.gov (United States)

    Cruz, Aristides I; Shea, Kevin G; Ganley, Theodore J

    2016-10-01

    Osteochondritis dissecans (OCD) can cause knee pain and dysfunction in children. The etiology of OCD remains unclear; theories on causes include inflammation, ischemia, ossification abnormalities, genetic factors, and repetitive microtrauma. Most OCD lesions in skeletally immature patients will heal with nonoperative treatment. The success of nonoperative treatment decreases once patients reach skeletal maturity. The goals of surgical treatment include maintenance of articular cartilage congruity, rigid fixation of unstable fragments, and repair of osteochondral defects with cells or tissues that can adequately replace lost or deficient cartilage. Unsalvageable OCD lesions can be treated with various surgical techniques.

  6. Spontaneous hyaline cartilage regeneration can be induced in an osteochondral defect created in the femoral condyle using a novel double-network hydrogel

    National Research Council Canada - National Science Library

    Yokota, Masashi; Yasuda, Kazunori; Kitamura, Nobuto; Arakaki, Kazunobu; Onodera, Shin; Kurokawa, Takayuki; Gong, Jian-Ping

    2011-01-01

    .... The purpose is to clarify whether the spontaneous hyaline cartilage regeneration can be induced in a large osteochondral defect created in the femoral condyle by means of implanting a novel double-network (DN...

  7. Pain in osteochondral lesions.

    Science.gov (United States)

    Wiewiorski, Martin; Pagenstert, Geert; Rasch, Helmut; Jacob, Augustinus Ludwig; Valderrabano, Victor

    2011-04-01

    Pain is the key symptom of patients suffering from osteochondral lesions (OCLs) of the ankle joint. Routine radiographic imaging methods for diagnosis and staging of OCL fail to visualize the pain-inducing focus within the joint. SPECT-CT (Single-photon emission computed tomography-computed tomography) is a new hybrid imaging technique allowing exact digital fusion of scintigraphic and computer tomographic images. This allows precise localization and size determination of an OCL within the joint. Using this novel imaging method, we conducted a study to evaluate the correlation between pathological uptake within an OCL and pain experienced by patients suffering from this condition; 15 patients were assessed in the orthopaedic ambulatory clinic for unilateral OCL of the ankle joint. Pain status was measured with the Visual Analogue Scale (VAS). A SPECT-CT was performed. All patients underwent CT-guided ankle injection with a local anesthetic and iodine contrast medium. The VAS score assessed immediately postinfiltration was compared with the preinterventional VAS score obtained in the outpatient clinic. Pain relief was defined as a reduction of the VAS score to ≤50% of the preinterventional score, if expected immediately after infiltration. Pain relief was found in all 15 patients. The results of our study show that there is a highly significant correlation between pain and pathological uptake seen on SPECT-CT, indicating that pathologically remodeled bone tissue is an important contributor to pain in OCL. Adequate addressing of involved bone tissue needs to be taken into consideration when choosing a surgical treatment method.

  8. 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.

  9. Repair of osteochondral defects with in vitro engineered cartilage based on autologous bone marrow stromal cells in a swine model

    Science.gov (United States)

    He, Aijuan; Liu, Lina; Luo, Xusong; Liu, Yu; Liu, Yi; Liu, Fangjun; Wang, Xiaoyun; Zhang, Zhiyong; Zhang, Wenjie; Liu, Wei; Cao, Yilin; Zhou, Guangdong

    2017-01-01

    Functional reconstruction of large osteochondral defects is always a major challenge in articular surgery. Some studies have reported the feasibility of repairing articular osteochondral defects using bone marrow stromal cells (BMSCs) and biodegradable scaffolds. However, no significant breakthroughs have been achieved in clinical translation due to the instability of in vivo cartilage regeneration based on direct cell-scaffold construct implantation. To overcome the disadvantages of direct cell-scaffold construct implantation, the current study proposed an in vitro cartilage regeneration strategy, providing relatively mature cartilage-like tissue with superior mechanical properties. Our strategy involved in vitro cartilage engineering, repair of osteochondral defects, and evaluation of in vivo repair efficacy. The results demonstrated that BMSC engineered cartilage in vitro (BEC-vitro) presented a time-depended maturation process. The implantation of BEC-vitro alone could successfully realize tissue-specific repair of osteochondral defects with both cartilage and subchondral bone. Furthermore, the maturity level of BEC-vitro had significant influence on the repaired results. These results indicated that in vitro cartilage regeneration using BMSCs is a promising strategy for functional reconstruction of osteochondral defect, thus promoting the clinical translation of cartilage regeneration techniques incorporating BMSCs. PMID:28084417

  10. Evaluation of Magnetic Nanoparticle-Labeled Chondrocytes Cultivated on a Type II Collagen–Chitosan/Poly(Lactic-co-Glycolic) Acid Biphasic Scaffold

    OpenAIRE

    Juin-Yih Su; Shi-Hui Chen; Yu-Pin Chen; Wei-Chuan Chen

    2017-01-01

    Chondral or osteochondral defects are still controversial problems in orthopedics. Here, chondrocytes labeled with magnetic nanoparticles were cultivated on a biphasic, type II collagen–chitosan/poly(lactic-co-glycolic acid) scaffold in an attempt to develop cultures with trackable cells exhibiting growth, differentiation, and regeneration. Rabbit chondrocytes were labeled with magnetic nanoparticles and characterized by scanning electron microscopy (SEM), transmission electron (TEM) microsco...

  11. Drilling techniques for osteochondritis dissecans.

    Science.gov (United States)

    Heyworth, Benton E; Edmonds, Eric W; Murnaghan, M Lucas; Kocher, Mininder S

    2014-04-01

    Although the advanced stages of osteochondritis dissecans remain challenging to treat, most early-stage lesions in skeletally immature patients, if managed appropriately, can be stimulated to heal. For stable lesions that do not demonstrate adequate healing with nonoperative measures, such as activity modification, weight-bearing protection, or bracing, drilling of the subchondral bone has emerged as the gold standard of management. Several techniques of drilling exist, including transarticular drilling, retroarticular drilling, and notch drilling. Although each technique has been shown to be effective in small retrospective studies, higher-powered prospective comparative studies are needed to better elucidate their relative advantages and disadvantages.

  12. Implante de condrócitos homólogos em defeitos osteocondrais de cães: padronização da técnica e avaliação histopatológica Homologous articular chondrocytes implantation in osteochondral defects of dogs: technique and histopathological evaluation standardization

    Directory of Open Access Journals (Sweden)

    L.S. Iamaguti

    2013-02-01

    Full Text Available Padronizou-se a metodologia para cultura de condrócitos em cães e avaliou-se seu implante em lesões osteocondrais, utilizando-se a membrana biossintética de celulose (MBC como revestimento. Dez cães, adultos e clinicamente sadios, foram submetidos à artrotomia das articulações fêmoro-tíbio-patelares. Defeitos de 4mm de diâmetro e profundidade foram induzidos no sulco troclear de ambos os membros. MBC foi aplicada na base e na superfície das lesões. Os defeitos do membro direito foram preenchidos com condrócitos homólogos cultivados formando o grupo-tratado (GT; os do membro esquerdo, sem implante celular, foram designados grupo-controle (GC. A evolução pós-operatória foi analisada com especial interesse nos processos de reparação da lesão, por meio de histomorfometria e imuno-histoquímica para colágeno tipo II e sulfato de condroitina. A cultura de condrócitos homólogos apresentou alta densidade e taxa de viabilidade. Observou-se integridade do tecido neoformado com a cartilagem adjacente na avaliação histológica, em ambos os grupos. Na imuno-histoquímica, verificou-se predomínio de colágeno tipo II no GT. Morfometricamente, não houve diferença significativa entre o tecido fibroso e o fibrocartilaginoso entre os grupos. A cultura de condrócitos homólogos de cães foi exequível. O tecido neoformado apresentou qualidade discretamente superior associado ao implante homólogo de condrócitos, contudo não promoveu reparação por cartilagem hialina.The aim of the study is to standardize the methodology to achieve canine chondrocytes culture, and evaluate its implant on osteochondral defects made in the femoral trochlear sulcus of dogs, using the cellulose biosynthetic membrane (CBM as coating. Ten healthy adult dogs without locomotor disorders were used. All animals were submitted to arthrotomy of stifle joints and defects of four millimeters in diameter x four millimeters deep were done in the femoral trochlear

  13. Viral Inactivation of Human Osteochondral Grafts with Methylene Blue and Light.

    Science.gov (United States)

    Squillace, Donna M; Zhao, Zhixing; Call, Gazell M; Gao, Jizong; Yao, Jian Q

    2014-01-01

    Cartilage injury is one of the most common disorders of synovial joints. Fresh osteochondral allografts are becoming a standard treatment; however, they are supply constrained with a potential risk of disease transmission. There are no known virucidal processes available for osteochondral allografts and most methods presently available are detrimental to cartilage. Methylene blue light treatment has been shown to be successful in the literature for viral inactivation of fresh frozen plasma. The purpose of this study was to determine the capacity of methylene blue light treatment to inactivate a panel of clinically relevant viruses inoculated onto osteochondral allografts. Osteochondral grafts recovered from human cadaveric knees were inoculated with one of the following viruses: bovine viral diarrhea virus (BVDV), hepatitis A virus (HAV), human immunodeficiency virus type 1 (HIV-1), porcine parvovirus (PPV), and pseudorabies virus (PrV). The samples were processed through a methylene blue light treatment, which consisted of an initial soak in nonilluminated circulating methylene blue at ambient temperature, followed by light exposure with circulating methylene blue at cool temperatures. The final titer was compared with the recovery control for the viral log reduction. HIV-1, BVDV, and PrV were reduced to nondetectable levels while HAV and PPV were reduced by 3.1 and 5.6 logs, respectively. The methylene blue light treatment was effective in reducing (a) enveloped DNA and RNA viruses to nondetectable levels and (b) nonenveloped DNA and RNA viruses of inoculated human osteochondral grafts by 3.1 to 5.6 logs. This study demonstrates the first practical method for significantly reducing viral load in osteochondral implants.

  14. The use of PLDLA/PCL-T scaffold to repair osteochondral defects in vivo

    Directory of Open Access Journals (Sweden)

    Andrea Rodrigues Esposito

    2013-02-01

    Full Text Available The physiological repair of osteochondral lesions requires the development of a scaffold that is compatible with the structure of the damaged tissue, cartilage and bone. The aim of this study was to evaluate the biological performance of a PLDLA/PCL-T (90/10 scaffold for repairing osteochondral defects in rabbits. Polymeric scaffolds containing saccharose (75% w/v were obtained by solvent casting and then implanted in the medial knee condyles of 12 New Zealand rabbits after osteochondral damage with a trephine metallic drill (diameter: 3.3 mm in both medial femoral condyles. Each rabbit received the same treatment, i.e., the polymeric scaffold was implanted on the right side while no material was implanted on the left side (control. Four and 12 weeks later histological examination revealed bone neoformation in the implant group, with the presence of hyaline cartilage and mesenchymal tissue. In contrast, the control group showed bone neoformation with necrosis, exacerbated superficial fibrosis, inflammation and cracks in the neoformed tissue. These findings indicate that the PLDLA/PCL-T scaffold was biocompatible and protected the condyles by stabilizing the lesion and allowing subchondral bone tissue and hyaline cartilage formation.

  15. The use of PLDLA/PCL-T scaffold to repair osteochondral defects in vivo

    Directory of Open Access Journals (Sweden)

    Andrea Rodrigues Esposito

    2012-01-01

    Full Text Available The physiological repair of osteochondral lesions requires the development of a scaffold that is compatible with the structure of the damaged tissue, cartilage and bone. The aim of this study was to evaluate the biological performance of a PLDLA/PCL-T (90/10 scaffold for repairing osteochondral defects in rabbits. Polymeric scaffolds containing saccharose (75% w/v were obtained by solvent casting and then implanted in the medial knee condyles of 12 New Zealand rabbits after osteochondral damage with a trephine metallic drill (diameter: 3.3 mm in both medial femoral condyles. Each rabbit received the same treatment, i.e., the polymeric scaffold was implanted on the right side while no material was implanted on the left side (control. Four and 12 weeks later histological examination revealed bone neoformation in the implant group, with the presence of hyaline cartilage and mesenchymal tissue. In contrast, the control group showed bone neoformation with necrosis, exacerbated superficial fibrosis, inflammation and cracks in the neoformed tissue. These findings indicate that the PLDLA/PCL-T scaffold was biocompatible and protected the condyles by stabilizing the lesion and allowing subchondral bone tissue and hyaline cartilage formation.

  16. Osteochondral repair in the rabbit model utilizing bilayered, degradable oligo(poly(ethylene glycol) fumarate) hydrogel scaffolds

    NARCIS (Netherlands)

    Holland, T.A.; Bodde, E.W.H.; Baggett, L.S.; Tabata, Y.; Mikos, A.G.; Jansen, J.A.

    2005-01-01

    In this study, hydrogel scaffolds, based on the polymer oligo(poly(ethylene glycol) fumarate) (OPF), were implanted into osteochondral defects in the rabbit model. Scaffolds consisted of two layers-a bottom, bone forming layer and a top, cartilage forming layer. Three scaffold formulations were impl

  17. The effect of interface microstructure on interfacial shear strength for osteochondral scaffolds based on biomimetic design and 3D printing.

    Science.gov (United States)

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

    2015-01-01

    Interface integration between chondral phase and osseous phase is crucial in engineered osteochondral scaffolds. However, the integration was poorly understood and commonly failed to meet the need of osteochondral scaffolds. In this paper, a biphasic polyethylene glycol (PEG)/β-tricalcium phosphate (β-TCP) scaffold with enhanced interfacial integration was developed. The chondral phase was a PEG hydrogel. The osseous phase was a β-TCP ceramic scaffold. The PEG hydrogel was directly cured on the ceramic interface layer by layer to fabricate osteochondral scaffolds by 3D printing technology. Meanwhile, a series of interface structure were designed with different interface pore area percentages (0/10/20/30/40/50/60%), and interfacial shear test was applied for interface structure optimization (n=6 samples/group). The interfacial shear strength of 30% pore area group was nearly three folds improved compared with that of 0% pore area percentage group, and more than fifty folds improved compared with that of traditional integration (5.91±0.59 kPa). In conclusion, the biomimetic PEG/β-TCP scaffolds with interface structure enhanced integration show promising potential application for osteochondral tissue engineering. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Magnetic resonance imaging of hyaline cartilage regeneration in neocartilage graft implantation.

    Science.gov (United States)

    Tan, C F; Ng, K K; Ng, S H; Cheung, Y C

    2003-12-01

    The purpose of this study was to investigate the regenerative potential of hyaline cartilage in a neocartilage graft implant with the aid of MR cartilage imaging using a rabbit model. Surgical osteochondral defects were created in the femoral condyles of 30 mature New Zealand rabbits. The findings of neocartilage in autologous cartilage grafts packed into osteochondral defects were compared with control group of no implant to the osteochondral defect. The outcome of the implantations was correlated with histologic and MR cartilage imaging findings over a 3-month interval. Neocartilage grafts packed into osteochondral defects showed regeneration of hyaline cartilage at the outer layer of the implant using MR cartilage imaging. Fibrosis of fibrocartilage developed at the outer layer of the autologous cartilage graft together with an inflammatory reaction within the osteochondral defect. This animal study provides evidence of the regenerative ability of hyaline cartilage in neocartilage transplants to repair articular cartilage.

  19. Hyaline cartilage degenerates after autologous osteochondral transplantation.

    Science.gov (United States)

    Tibesku, C O; Szuwart, T; Kleffner, T O; Schlegel, P M; Jahn, U R; Van Aken, H; Fuchs, S

    2004-11-01

    Autologous osteochondral grafting is a well-established clinical procedure to treat focal cartilage defects in patients, although basic research on this topic remains sparse. The aim of the current study was to evaluate (1) histological changes of transplanted hyaline cartilage of osteochondral grafts and (2) the tissue that connects the transplanted cartilage with the adjacent cartilage in a sheep model. Both knee joints of four sheep were opened surgically and osteochondral grafts were harvested and simultaneously transplanted to the contralateral femoral condyle. The animals were sacrificed after three months and the received knee joints were evaluated histologically. Histological evaluation showed a complete ingrowth of the osseous part of the osteochondral grafts. A healing or ingrowth at the level of the cartilage could not be observed. Histological evaluation of the transplanted grafts according to Mankin revealed significantly more and more severe signs of degeneration than the adjacent cartilage, such as cloning of chondrocytes and irregularities of the articular surface. We found no connecting tissue between the transplanted and the adjacent cartilage and histological signs of degeneration of the transplanted hyaline cartilage. In the light of these findings, long-term results of autologous osteochondral grafts in human beings have to be followed critically.

  20. Hip Arthroscopic Osteochondral Autologous Transplantation for Treating Osteochondritis Dissecans of the Femoral Head.

    Science.gov (United States)

    Kubo, Takanori; Utsunomiya, Hajime; Watanuki, Makoto; Hayashi, Hidetoshi; Sakai, Akinori; Uchida, Soshi

    2015-12-01

    Osteochondritis dissecans (OCD) of the femoral head is not a common source of hip pain. Hip arthroscopy is becoming a more frequent indication for intra-articular pathologies of the hip. Osteochondral autologous transplantation is a promising technique that theoretically can reconstruct osteochondral lesions of the femoral head. We describe our technique for arthroscopic antegrade osteochondral autologous transplantation for the treatment of OCD of the femoral head. The advantages of this technique include that it is a less invasive method with the ability to assess and treat intra-articular pathologies associated with OCD of the femoral head at same time. Case series and outcomes after this technique are not currently reported in the literature; however, it could be a less invasive method and provide favorable clinical outcomes for patients with OCD lesions of the femoral head.

  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. Osteochondral defects in the ankle: why painful?

    NARCIS (Netherlands)

    van Dijk, C.N.; Reilingh, M.L.; Zengerink, M.; van Bergen, C.J.A.

    2010-01-01

    Osteochondral defects of the ankle can either heal and remain asymptomatic or progress to deep ankle pain on weight bearing and formation of subchondral bone cysts. The development of a symptomatic OD depends on various factors, including the damage and insufficient repair of the subchondral bone pl

  4. Osteochondral defects in the ankle: why painful?

    NARCIS (Netherlands)

    van Dijk, C.N.; Reilingh, M.L.; Zengerink, M.; van Bergen, C.J.A.

    2010-01-01

    Osteochondral defects of the ankle can either heal and remain asymptomatic or progress to deep ankle pain on weight bearing and formation of subchondral bone cysts. The development of a symptomatic OD depends on various factors, including the damage and insufficient repair of the subchondral bone pl

  5. Treatment of osteochondral defects of the talus

    NARCIS (Netherlands)

    C.J.A. van Bergen

    2014-01-01

    An osteochondral defect (OCD) of the talus involves the articular cartilage and subchondral bone. It most frequently appears in the second and third decade of life. A traumatic insult, usually ankle sprain, is the most frequent etiologic factor. The typical symptom is persistent or intermittent deep

  6. Evaluation and analysis of graft hypertrophy by means of arthroscopy, biochemical MRI and osteochondral biopsies in a patient following autologous chondrocyte implantation for treatment of a full-thickness-cartilage defect of the knee.

    Science.gov (United States)

    Niemeyer, Philipp; Uhl, Markus; Salzmann, Gian M; Morscheid, Yannik P; Südkamp, Norbert P; Madry, Henning

    2015-06-01

    Graft hypertrophy represents a characteristic complication following autologous chondrocyte implantation (ACI) for treatment of cartilage defects. Although some epidemiological data suggest that incidence is associated with first-generation ACI using autologous chondrocyte implantation, it has also been reported in other technical modifications of ACI using different biomaterials. Nevertheless, it has not been described in autologous, non-periosteum, implant-free associated ACI. In addition, little is known about histological and T2-relaxation appearance of graft hypertrophy. The present case report provides a rare case of extensive graft hypertrophy following ACI using an autologous spheres technique with clinical progression over time. Detailed clinical, MR tomographic and histological evaluation has been performed, which demonstrates a high quality of repair tissue within the hypertrophic as well as non-hypertrophic transplanted areas of the repair tissue. No expression of collagen type X (a sign of chondrocyte hypertrophy), only slight changes of the subchondral bone and a nearly normal cell-matrix ratio suggest that tissue within the hypertrophic area does not significantly differ from intact and high-quality repair tissue and therefore seems not to cause graft hypertrophy. This is in contrast to the assumption that histological hypertrophy might cause or contribute to an overwhelming growth of the repair tissue within the transplantation site. Data presented in this manuscript might contribute to further explain the etiology of graft hypertrophy following ACI.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Rabbit trochlear model of osteochondral allograft transplantation.

    Science.gov (United States)

    To, Nhat; Curtiss, Shane; Neu, Corey P; Salgado, Christopher J; Jamali, Amir A

    2011-10-01

    Allografting and autografting of osteochondral tissues is a promising strategy to treat articular cartilage lesions in damaged joints. We developed a new model of fresh osteochondral allografting using the entire rabbit trochlea. The objective of the current study was to demonstrate that this model would achieve reproducible graft-host healing and maintain normal articular cartilage histologic, immunolocalization, and biochemical characteristics after transplantation under diverse storage and transplantation conditions. New Zealand white (n = 8) and Dutch belted (n = 8) rabbits underwent a 2-stage transplantation operation using osteochondral grafts that had been stored for 2 or 4 wk. Trochlear grafts harvested from the left knee were transplanted to the right knee as either autografts or allografts. Grafts were fixed with 22-gauge steel wire or 3-0 nylon suture. Rabbits were euthanized for evaluation at 1, 2, 4, 6, and 12 wk after transplantation. All grafts that remained in vivo for at least 4 wk demonstrated 100% interface healing by microCT. Trabecular bridging was present at the host-graft interface starting at 2 wk after transplantation, with no significant difference in cartilage histology between the various groups. The combined histology scores indicated minimal evidence of osteoarthritis. Immunostaining revealed that superficial zone protein was localized at the surface of all transplants. The rabbit trochlear model met our criteria for a successful model in regard to the ease of the procedure, low rate of surgical complications, relatively large articular cartilage surface area, and amount of host-graft bone interface available for analysis.

  9. Cartilage repair: A review of stanmore experience in the treatment of osteochondral defects in the knee with various surgical techniques

    Directory of Open Access Journals (Sweden)

    Vijayan S

    2010-01-01

    Full Text Available Articular cartilage damage in the young adult knee, if left untreated, it may proceed to degenerative osteoarthritis and is a serious cause of disability and loss of function. Surgical cartilage repair of an osteochondral defect can give the patient significant relief from symptoms and preserve the functional life of the joint. Several techniques including bone marrow stimulation, cartilage tissue based therapy, cartilage cell seeded therapies and osteotomies have been described in the literature with varying results. Established techniques rely mainly on the formation of fibro-cartilage, which has been shown to degenerate over time due to shear forces. The implantation of autologous cultured chondrocytes into an osteochondral defect, may replace damaged cartilage with hyaline or hyaline-like cartilage. This clinical review assesses current surgical techniques and makes recommendations on the most appropriate method of cartilage repair when managing symptomatic osteochondral defects of the knee. We also discuss the experience with the technique of autologous chondrocyte implantation at our institution over the past 11 years.

  10. Spontaneous hyaline cartilage regeneration can be induced in an osteochondral defect created in the femoral condyle using a novel double-network hydrogel.

    Science.gov (United States)

    Yokota, Masashi; Yasuda, Kazunori; Kitamura, Nobuto; Arakaki, Kazunobu; Onodera, Shin; Kurokawa, Takayuki; Gong, Jian-Ping

    2011-02-22

    Functional repair of articular osteochondral defects remains a major challenge not only in the field of knee surgery but also in tissue regeneration medicine. The purpose is to clarify whether the spontaneous hyaline cartilage regeneration can be induced in a large osteochondral defect created in the femoral condyle by means of implanting a novel double-network (DN) gel at the bottom of the defect. Twenty-five mature rabbits were used in this study. In the bilateral knees of each animal, we created an osteochondral defect having a diameter of 2.4-mm in the medial condyle. Then, in 21 rabbits, we implanted a DN gel plug into a right knee defect so that a vacant space of 1.5-mm depth (in Group I), 2.5-mm depth (in Group II), or 3.5-mm depth (in Group III) was left. In the left knee, we did not apply any treatment to the defect to obtain the control data. All the rabbits were sacrificed at 4 weeks, and the gross and histological evaluations were performed. The remaining 4 rabbits underwent the same treatment as used in Group II, and real-time PCR analysis was performed at 4 weeks. The defect in Group II was filled with a sufficient volume of the hyaline cartilage tissue rich in proteoglycan and type-2 collagen. The Wayne's gross appearance and histology scores showed that Group II was significantly greater than Group I, III, and Control (p hyaline cartilage regeneration can be induced in vivo in an osteochondral defect created in the femoral condyle by means of implanting the DN gel plug at the bottom of the defect so that an approximately 2-mm deep vacant space was intentionally left in the defect. This fact has prompted us to propose an innovative strategy without cell culture to repair osteochondral lesions in the femoral condyle.

  11. Spontaneous hyaline cartilage regeneration can be induced in an osteochondral defect created in the femoral condyle using a novel double-network hydrogel

    Directory of Open Access Journals (Sweden)

    Onodera Shin

    2011-02-01

    Full Text Available Abstract Background Functional repair of articular osteochondral defects remains a major challenge not only in the field of knee surgery but also in tissue regeneration medicine. The purpose is to clarify whether the spontaneous hyaline cartilage regeneration can be induced in a large osteochondral defect created in the femoral condyle by means of implanting a novel double-network (DN gel at the bottom of the defect. Methods Twenty-five mature rabbits were used in this study. In the bilateral knees of each animal, we created an osteochondral defect having a diameter of 2.4-mm in the medial condyle. Then, in 21 rabbits, we implanted a DN gel plug into a right knee defect so that a vacant space of 1.5-mm depth (in Group I, 2.5-mm depth (in Group II, or 3.5-mm depth (in Group III was left. In the left knee, we did not apply any treatment to the defect to obtain the control data. All the rabbits were sacrificed at 4 weeks, and the gross and histological evaluations were performed. The remaining 4 rabbits underwent the same treatment as used in Group II, and real-time PCR analysis was performed at 4 weeks. Results The defect in Group II was filled with a sufficient volume of the hyaline cartilage tissue rich in proteoglycan and type-2 collagen. The Wayne's gross appearance and histology scores showed that Group II was significantly greater than Group I, III, and Control (p Conclusions This study demonstrated that spontaneous hyaline cartilage regeneration can be induced in vivo in an osteochondral defect created in the femoral condyle by means of implanting the DN gel plug at the bottom of the defect so that an approximately 2-mm deep vacant space was intentionally left in the defect. This fact has prompted us to propose an innovative strategy without cell culture to repair osteochondral lesions in the femoral condyle.

  12. Comparative, osteochondral defect repair: Stem cells versus chondrocytes versus Bone Morphogenetic Protein-2, solely or in combination

    Directory of Open Access Journals (Sweden)

    R Reyes

    2013-07-01

    Full Text Available Full-thickness articular cartilage damage does not resolve spontaneously. Studies with growth factors, implantation of autologous chondrocytes and mesenchymal stem cells have led to variable, to some extent inconsistent, results. This work compares osteochondral knee-defect repair in rabbits upon implantation of a previously described alginate/(poly(lactic-co-glycolic acid (PLGA osteochondral scaffold in distinct conditions. Systems were either in vitro pre-cultured with a small number of allogeneic chondrocytes under fibroblast growth factor (FGF-2 stimulation or the same amount of allogeneic, marrow derived, mesenchymal stem cells (without any pre-differentiation, or loaded with microsphere-encapsulated bone morphogenetic protein (BMP-2 within the alginate layer, or holding combinations of one or the other cell type with BMP-2. The experimental limit was 12 weeks, because a foregoing study with this release system had shown a maintained tissue response for at least 24 weeks post-operation. After only 6 weeks, histological analyses revealed newly formed cartilage-like tissue, which resembled the adjacent, normal cartilage in cell as well as BMP-2 treated defects, but cell therapy gave higher histological scores. This advantage evened out until 12 weeks. Combinations of cells and BMP-2 did not result in any additive or synergistic effect. Equally efficient osteochondral defect repair was achieved with chondrocyte, stem cell, and BMP-2 treatment. Expression of collagen X and collagen I, signs of ongoing ossification, were histologically undetectable, and the presence of aggrecan protein indicated cartilage-like tissue. In conclusion, further work should demonstrate whether spatiotemporally controlled, on-site BMP-2 release alone could become a feasible therapeutic approach to repair large osteochondral defects.

  13. Current management of talar osteochondral lesions

    Science.gov (United States)

    Gianakos, Arianna L; Yasui, Youichi; Hannon, Charles P; Kennedy, John G

    2017-01-01

    Osteochondral lesions of the talus (OLT) occur in up to 70% of acute ankle sprains and fractures. OLT have become increasingly recognized with the advancements in cartilage-sensitive diagnostic imaging modalities. Although OLT may be treated nonoperatively, a number of surgical techniques have been described for patients whom surgery is indicated. Traditionally, treatment of symptomatic OLT have included either reparative procedures, such as bone marrow stimulation (BMS), or replacement procedures, such as autologous osteochondral transplantation (AOT). Reparative procedures are generally indicated for OLT < 150 mm2 in area. Replacement strategies are used for large lesions or after failed primary repair procedures. Although short- and medium-term results have been reported, long-term studies on OLT treatment strategies are lacking. Biological augmentation including platelet-rich plasma and concentrated bone marrow aspirate is becoming increasingly popular for the treatment of OLT to enhance the biological environment during healing. In this review, we describe the most up-to-date clinical evidence of surgical outcomes, as well as both the mechanical and biological concerns associated with BMS and AOT. In addition, we will review the recent evidence for biological adjunct therapies that aim to improve outcomes and longevity of both BMS and AOT procedures. PMID:28144574

  14. Treatment of osteochondral injuries with platelet gel

    Directory of Open Access Journals (Sweden)

    Marcus Vinicius Danieli

    2014-12-01

    Full Text Available OBJECTIVES: Treatments for injured articular cartilage have not advanced to the point that efficient regeneration is possible. However, there has been an increase in the use of platelet-rich plasma for the treatment of several orthopedic disorders, including chondral injuries. Our hypothesis is that the treatment of chondral injuries with platelet gel results in higher-quality repair tissue after 180 days compared with chondral injuries not treated with gel. METHODS: A controlled experimental laboratory study was performed on 30 male rabbits to evaluate osteochondral injury repair after treatment with or without platelet gel. Osteochondral injuries were surgically induced in both knees of each rabbit at the medial femoral condyle. The left knee injury was filled with the platelet gel, and the right knee was not treated. Microscopic analysis of both knee samples was performed after 180 days using a histological grading scale. RESULTS: The only histological evaluation criterion that was not significantly different between treatments was metachromasia. The group that was treated with platelet gel exhibited superior results in all other criteria (cell morphology, surface regularity, chondral thickness and repair tissue integration and in the total score. CONCLUSION: The repair tissue was histologically superior after 180 days in the study group treated with platelet gel compared with the group of untreated injuries.

  15. Fresh-Stored Osteochondral Allograft for Treatment of Osteochondritis Dissecans the Femoral Head

    Science.gov (United States)

    2010-01-01

    Masonis JL. Cementless femoral components in young patients: review and meta-analysis of total hip arthroplasty and hip resurfacing . J Arthroplasty...osteochondral allograft via a trochanteric osteotomy. Case Report A healthy 32-year-old man had worsening left hip pain after jumping off a vehicle from a...height of approximately 4 feet. In the subsequent months, the patient had mechan- ical symptoms of the affected hip , including catching and Each author

  16. Osteochondritis dissecans after rotational acetabular osteotomy for dysplastic hip

    Energy Technology Data Exchange (ETDEWEB)

    Nozawa, Masahiko; Maezawa, Katsuhiko; Yuasa, Takahito; Morimoto, Kouichi; Asakura, Taro; Kurosawa, Hisashi [Juntendo University School of Medicine, Department of Orthopaedic Surgery, Tokyo (Japan)

    2005-12-01

    We encountered a rare case of osteochondritis dissecans of the femoral head after rotational acetabular osteotomy that recovered with conservative treatment 4 years after the detection of characteristic radiological findings. (orig.)

  17. 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.

  18. A new bi-layered scaffold for osteochondral tissue regeneration: In vitro and in vivo preclinical investigations.

    Science.gov (United States)

    Sartori, M; Pagani, S; Ferrari, A; Costa, V; Carina, V; Figallo, E; Maltarello, M C; Martini, L; Fini, M; Giavaresi, G

    2017-01-01

    Current treatments for acute or degenerative chondral and osteochondral lesions are in need of improvement, as these types of injuries lead to disability and worsen the quality of life in a high percentage of patients. The aim of this study was to develop a new bi-layered scaffold for osteochondral tissue regeneration through a "biomimetic" and "bioinspired" approach. For chondral regeneration, the scaffold was realized with an organic compound (type I collagen), while for the regeneration of the subchondral layer, bioactive magnesium-doped hydroxyapatite (Mg/HA) crystals were co-precipitated with the organic component of the scaffold. The entire scaffold structure was stabilized with a cross-linking agent, highly reactive bis-epoxyde (1,4-butanediol diglycidyl ether - BDDGE 1wt%). The developed scaffold was then characterized for its physico-chemical characteristics. Its structure and adhesion strength between the integrated layers were investigated. At the same time, in vitro cell culture studies were carried out to examine the ability of chondral and bone scaffold layers to separately support adhesion, proliferation and differentiation of human mesenchymal stem cells (hMSCs) into chondrocytes and osteoblasts, respectively. Moreover, an in vivo study with nude mice, transplanted with osteochondral scaffolds plain or engineered with undifferentiated hMSCs, was also set up with 4 and 8-week time points. The results showed that chondral and bone scaffold layers represented biocompatible scaffolds able to sustain hMSCs attachment and proliferation. Moreover, the association of scaffold stimuli and differentiation medium, induced hMSCs chondrogenic and osteogenic differentiation and deposition of extracellular matrix (ECM). The ectopic implantation of the engineered osteochondral scaffolds indicated that hMSCs were able to colonize the osteochondral scaffold in depth. The scaffold appeared permissive to tissue growth and penetration, ensuring the diffusion of

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

    Directory of Open Access Journals (Sweden)

    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.

  20. 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.)

  1. Development of a Fresh Osteochondral Allograft Program Outside North America.

    Science.gov (United States)

    Tírico, Luís Eduardo Passarelli; Demange, Marco Kawamura; Santos, Luiz Augusto Ubirajara; de Rezende, Márcia Uchoa; Helito, Camilo Partezani; Gobbi, Riccardo Gomes; Pécora, José Ricardo; Croci, Alberto Tesconi; Bugbee, William Dick

    2016-07-01

    To standardize and to develop a fresh osteochondral allograft protocol of procurement, processing and surgical utilization in Brazil. This study describes the steps recommended to make fresh osteochondral allografts a viable treatment option in a country without previous fresh allograft availability. The process involves regulatory process modification, developing and establishing procurement, and processing and surgical protocols. Legislation: Fresh osteochondral allografts were not feasible in Brazil until 2009 because the law prohibited preservation of fresh grafts at tissue banks. We approved an amendment that made it legal to preserve fresh grafts for 30 days from 2°C to 6°C in tissue banks. Procurement: We changed the protocol of procurement to decrease tissue contamination. All tissues were procured in an operating room. Processing: Processing of the grafts took place within 12 hours of tissue recovery. A serum-free culture media with antibiotics was developed to store the grafts. Surgeries: We have performed 8 fresh osteochondral allografts on 8 knees obtaining grafts from 5 donors. Mean preoperative International Knee Documentation Committee (IKDC) score was 31.99 ± 13.4, improving to 81.26 ± 14.7 at an average of 24 months' follow-up. Preoperative Knee Injury and Oseoarthritis Outcome Score (KOOS) score was 46.8 ± 20.9 and rose to 85.24 ± 13.9 after 24 months. Mean preoperative Merle D'Aubigne-Postel score was 8.75 ± 2.25 rising to 16.1 ± 2.59 at 24 months' follow-up. To our knowledge, this is the first report of fresh osteochondral allograft transplantation in South America. We believe that this experience may be of value for physicians in countries that are trying to establish an osteochondral allograft transplant program.

  2. Osteochondritis dissecans of the subtalar articular facet: an unusual diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Madi, Faouzi; Vialle, Raphael; Mary, Pierre; Damsin, Jean-Paul; Filipe, Georges [Armand Trousseau Hospital, Department of Paediatric Orthopaedics, Paris Cedex 12 (France); Ducou le Pointe, Hubert [Armand Trousseau Hospital, Department of Radiology, Paris (France)

    2005-08-01

    Osteochondritis dissecans of the talus is classically characterized by an abnormality of the articular cartilage of the talar dome. We report a rare case of a lesion of the subtalar facet in a 10-year-old boy. The lesion was responsible for a painful ankle with secondary instability. The diagnosis was made using plain radiographs and CT, which showed a well-circumscribed osteochondral fragment demarcated from the adjacent bone by a radiolucent line. The clinical outcome was favourable after a 6-week period with a non-weight-bearing short-leg cast. (orig.)

  3. [Femoral head chondroblastoma and reconstruction with osteochondral allograft. Case report].

    Science.gov (United States)

    Orlando-Díaz, C; Guzmán-Vargas, R; Rincon-Cardozo, D F; Mantilla-León, N; Camacho-Casas, J A

    2014-01-01

    Femoral head chondroblastoma is an infrequent tumor, accounting for approximately 1-2% of benign bone tumors. It occurs more frequently in young male patients. It's most frequent locations include the proximal humerus, proximal femur, distal femur and proximal tibia. The femoral head is the third most frequent site of this tumor. There is no specific treatment for this entity; reported treatments range from acetabular osteotomies and osteochondral grafts, to vascularized fibular grafts, all of them with good results. However, this tumor is clinically unpredictable if left untreated. We report a case managed with osteochondral graft and followed-up for three years after the surgical procedure.

  4. Cell-free multi-layered collagen-based scaffolds demonstrate layer specific regeneration of functional osteochondral tissue in caprine joints.

    Science.gov (United States)

    Levingstone, Tanya J; Ramesh, Ashwanth; Brady, Robert T; Brama, Pieter A J; Kearney, Clodagh; Gleeson, John P; O'Brien, Fergal J

    2016-05-01

    Developing repair strategies for osteochondral tissue presents complex challenges due to its interfacial nature and complex zonal structure, consisting of subchondral bone, intermediate calcified cartilage and the superficial cartilage regions. In this study, the long term ability of a multi-layered biomimetic collagen-based scaffold to repair osteochondral defects is investigated in a large animal model: namely critical sized lateral trochlear ridge (TR) and medial femoral condyle (MC) defects in the caprine stifle joint. The study thus presents the first data in a clinically applicable large animal model. Scaffold fixation and early integration was demonstrated at 2 weeks post implantation. Macroscopic analysis demonstrated improved healing in the multi-layered scaffold group compared to empty defects and a market approved synthetic polymer osteochondral scaffold groups at 6 and 12 months post implantation. Radiological analysis demonstrated superior subchondral bone formation in both defect sites in the multi-layered scaffold group as early as 3 months, with complete regeneration of subchondral bone by 12 months. Histological analysis confirmed the formation of well-structured subchondral trabecular bone and hyaline-like cartilage tissue in the multi-layered scaffold group by 12 months with restoration of the anatomical tidemark. Demonstration of improved healing following treatment with this natural polymer scaffold, through the recruitment of host cells with no requirement for pre-culture, shows the potential of this device for the treatment of patients presenting with osteochondal lesions.

  5. Bipolar fresh osteochondral allograft of the ankle.

    Science.gov (United States)

    Giannini, Sandro; Buda, Roberto; Grigolo, Brunella; Bevoni, Roberto; Di Caprio, Francesco; Ruffilli, Alberto; Cavallo, Marco; Desando, Giovanna; Vannini, Francesca

    2010-01-01

    Severe post-traumatic ankle arthritis poses a reconstructive challenge in the young and active patient. Bipolar fresh osteochondral allograft (BFOA) may represent an intriguing alternative to arthrodesis and prosthetic replacement. The aim of this study was to describe a lateral trans-malleolar technique for BFOA, and to evaluate the results in a case series. From 2004 to 2006, 32 patients, mean age of 36.8 +/- 8.4 years, affected by ankle arthritis underwent BFOA with a mean followup of 31.2 months. The graft was prepared by specifically designed jigs, including the talus and the tibia with the medial malleolus. The host surfaces were prepared by the same jigs through a lateral approach. The graft was placed and fixed with twist-off screws. Patients were evaluated clinically and radiographically at 2, 4, and 6 month after operation, and at a minimum 24 months followup. A biopsy of the grafted areas was obtained from 7 patients at 1-year followup for histological and immunohistochemical examination. Preoperative AOFAS score was 33.1 +/- 10.9 and postoperatively 69.5 +/- 19.4 (p < 0.0005). Six failures occurred. Cartilage harvests showed hyaline-like histology with a normal collagen component but low proteoglycan presence and a disorganized structure. Samples were positive for MMP-1, MMP-13 and Capsase-3. The use of BFOA represents an intriguing alternative to arthrodesis or arthroplasty. We believe precise allograft sizing, stable fitting and fixation and delayed weightbearing were key factors for a successful outcome. Further research regarding the immunological behavior of transplanted cartilage is needed.

  6. Large fresh osteochondral allografts of the knee: a systematic clinical and basic science review of the literature.

    Science.gov (United States)

    De Caro, Francesca; Bisicchia, Salvatore; Amendola, Annunziato; Ding, Lei

    2015-04-01

    The aim of this study was to conduct an updated review of the literature regarding the clinical and basic science knowledge on osteochondral allograft transplantation in the knee for the treatment of large defects. According to specific criteria, 2 investigators systematically reviewed the literature for clinical and basic science reports regarding osteochondral allograft transplantation; data were independently extracted, pooled, and analyzed. Clinical and functional outcomes, International Knee Documentation Committee and Western Ontario and McMaster Universities Osteoarthritis Index scores, return to sport, quality of life, and survivorship of the grafts were assessed from the clinical articles. Regarding the basic science articles, the effects of allograft storage time, temperature, and different storage media were assessed. Eleven articles reporting on clinical data and 14 articles reporting on basic science data (animal, cell, and biomechanical studies) were selected. The articles included in the review were not homogeneous, and different outcome measures were adopted. Overall excellent results were achieved, with improvement in all objective and subjective clinical scores, a high rate of return to sport, and a survivorship rate of 89% at 5 years. When multiple plugs were implanted, posterior grafts seemed to fail. Only 1 article compared fresh versus frozen grafts, with a greater improvement in scores in the frozen group. Cellular viability and number were reduced during storage, even at low temperatures; polyphenol from green tea and arbutin and higher temperatures favorably influenced cell viability of the cartilage during storage. On the other hand, the structural properties of the extracellular matrix were not influenced by the storage at low temperatures. Integration of the graft to the host was also important, and bony integration was usually achieved; however, on the cartilage side, integration was scant or did not occur, especially in the frozen

  7. Evaluation of Magnetic Nanoparticle-Labeled Chondrocytes Cultivated on a Type II Collagen–Chitosan/Poly(Lactic-co-Glycolic Acid Biphasic Scaffold

    Directory of Open Access Journals (Sweden)

    Juin-Yih Su

    2017-01-01

    Full Text Available Chondral or osteochondral defects are still controversial problems in orthopedics. Here, chondrocytes labeled with magnetic nanoparticles were cultivated on a biphasic, type II collagen–chitosan/poly(lactic-co-glycolic acid scaffold in an attempt to develop cultures with trackable cells exhibiting growth, differentiation, and regeneration. Rabbit chondrocytes were labeled with magnetic nanoparticles and characterized by scanning electron microscopy (SEM, transmission electron (TEM microscopy, and gene and protein expression analyses. The experimental results showed that the magnetic nanoparticles did not affect the phenotype of chondrocytes after cell labeling, nor were protein and gene expression affected. The biphasic type II collagen–chitosan/poly(lactic-co-glycolic acid scaffold was characterized by SEM, and labeled chondrocytes showed a homogeneous distribution throughout the scaffold after cultivation onto the polymer. Cellular phenotype remained unaltered but with increased gene expression of type II collagen and aggrecan, as indicated by cell staining, indicating chondrogenesis. Decreased SRY-related high mobility group-box gene (Sox-9 levels of cultured chondrocytes indicated that differentiation was associated with osteogenesis. These results are encouraging for the development of techniques for trackable cartilage regeneration and osteochondral defect repair which may be applied in vivo and, eventually, in clinical trials.

  8. Evaluation of Magnetic Nanoparticle-Labeled Chondrocytes Cultivated on a Type II Collagen-Chitosan/Poly(Lactic-co-Glycolic) Acid Biphasic Scaffold.

    Science.gov (United States)

    Su, Juin-Yih; Chen, Shi-Hui; Chen, Yu-Pin; Chen, Wei-Chuan

    2017-01-04

    Chondral or osteochondral defects are still controversial problems in orthopedics. Here, chondrocytes labeled with magnetic nanoparticles were cultivated on a biphasic, type II collagen-chitosan/poly(lactic-co-glycolic acid) scaffold in an attempt to develop cultures with trackable cells exhibiting growth, differentiation, and regeneration. Rabbit chondrocytes were labeled with magnetic nanoparticles and characterized by scanning electron microscopy (SEM), transmission electron (TEM) microscopy, and gene and protein expression analyses. The experimental results showed that the magnetic nanoparticles did not affect the phenotype of chondrocytes after cell labeling, nor were protein and gene expression affected. The biphasic type II collagen-chitosan/poly(lactic-co-glycolic) acid scaffold was characterized by SEM, and labeled chondrocytes showed a homogeneous distribution throughout the scaffold after cultivation onto the polymer. Cellular phenotype remained unaltered but with increased gene expression of type II collagen and aggrecan, as indicated by cell staining, indicating chondrogenesis. Decreased SRY-related high mobility group-box gene (Sox-9) levels of cultured chondrocytes indicated that differentiation was associated with osteogenesis. These results are encouraging for the development of techniques for trackable cartilage regeneration and osteochondral defect repair which may be applied in vivo and, eventually, in clinical trials.

  9. 距骨骨软骨损伤手术治疗的研究进展%Research progress on operative treatment of osteochondral lesions of the talus

    Institute of Scientific and Technical Information of China (English)

    王双利; 潘政军; 江华; 黄彰

    2016-01-01

    目的:总结距骨骨软骨损伤(OLT)的手术治疗方法。方法在 PubMed、Springer link英文期刊全文数据库以“osteochondral lesions”、“talus”为关键词查阅2010年1月—2014年11月有关OLT 手术治疗方法的相关文献,进行总结分析。结果治疗 OLT 常用的手术方法包括清创、微骨折或钻孔术,自体或异体骨软骨移植术,自体软骨细胞移植术等多种方法。清创、微骨折或钻孔术一般适用于年轻、损伤面积小而浅或孤立病灶的患者。面积大、深的软骨及软骨下骨损伤可考虑自体或异体骨软骨移植术。关节镜手术因其微创、直视下操作及可同时进行诊断与治疗等优势,可做为手术治疗 OLT 的首选方式。目前,关节镜联合其他方法成为 OLT 治疗的新趋势。临床上儿童 OLT 少见,对保守治疗失败的 OLT 儿童,内固定和清创微骨折的手术治疗都是较好的手术方法。结论 OLT 有多种治疗方法,这些方法各有其适应证和优缺点,临床治疗应强调“个体化”原则,综合考虑患者的自身因素和病灶的特点,选择合适的手术方式。%Objective To summarize operative treatment of osteochondral lesions of the talus. Methods A computer-based search was conducted in PubMed and Springer link for literatures related to operative treatment of osteochondral lesions of the talus from January 2010 to November 2014 with the key words " osteochondral lesions" , " talus" in English. Analysis was conducted based on the articles. Results Surgical options are lesion excision, excision and curettage, microfracturing, antegrade ( transmalleolar) drilling, retrograde drilling, which are suitable for younger patients with small, superficial or isolated lesions, fixation and techniques such as osteochondral transplantation(autograft or allograft) and autologous chondrocyte implantation. Osteochondral transplantation is often applied if the damages are large

  10. Osteochondral defect repair using a polyvinyl alcohol-polyacrylic acid (PVA-PAAc) hydrogel.

    Science.gov (United States)

    Bichara, David A; Bodugoz-Sentruk, Hatice; Ling, Doris; Malchau, Erik; Bragdon, Charles R; Muratoglu, Orhun K

    2014-08-01

    Poly(vinyl alcohol) (PVA) hydrogels can be candidates for articular cartilage repair due to their high water content. We synthesized a PVA-poly(acrylic acid) (PAAc) hydrogel formulation and determined its ability to function as a treatment option for condylar osteochondral (OC) defects in a New Zealand white rabbit (NZWR) model for 12 weeks and 24 weeks. In addition to hydrogel OC implants, tensile bar-shaped hydrogels were also implanted subcutaneously to evaluate changes in mechanical properties as a function of in vivo duration. There were no statistically significant differences (p > 0.05) in the water content measured in the OC hydrogel implant that was harvested after 12 weeks and 24 weeks, and non-implanted controls. There were no statistically significant differences (p > 0.05) in the break stress, strain at break or modulus of the tensile bars either between groups. Histological analysis of the OC defect, synovial capsule and fibrous tissue around the tensile bars determined hydrogel biocompatibility. Twelve-week hydrogels were found to be in situ flush with the articular cartilage; meniscal tissue demonstrated an intact surface. Twenty-four week hydrogels protruded from the defect site due to lack of integration with subchondral tissue, causing fibrillation to the meniscal surface. Condylar micro-CT scans ruled out osteolysis and bone cysts of the subchondral bone, and no PVA-PAAc hydrogel contents were found in the synovial fluid. The PVA-PAAc hydrogel was determined to be fully biocompatible, maintained its properties over time, and performed well at the 12 week time point. Physical fixation of the PVA-PAAc hydrogel to the subchondral bone is required to ensure long-term performance of hydrogel plugs for OC defect repair.

  11. Acute Biphasic Effects of Ayahuasca.

    Directory of Open Access Journals (Sweden)

    Eduardo Ekman Schenberg

    Full Text Available Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important. Employing a combination of electroencephalogram (EEG recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8-13 Hz after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30-50 and 50-100 Hz, respectively between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca's chemical compounds, mostly N,N-dimethyltryptamine (DMT, harmine, harmaline and tetrahydroharmine and some of their metabolites. An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered.

  12. Acute Biphasic Effects of Ayahuasca

    Science.gov (United States)

    Schenberg, Eduardo Ekman; Alexandre, João Felipe Morel; Filev, Renato; Cravo, Andre Mascioli; Sato, João Ricardo; Muthukumaraswamy, Suresh D.; Yonamine, Maurício; Waguespack, Marian; Lomnicka, Izabela; Barker, Steven A.; da Silveira, Dartiu Xavier

    2015-01-01

    Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important. Employing a combination of electroencephalogram (EEG) recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8–13 Hz) after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30–50 and 50–100 Hz, respectively) between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca’s chemical compounds, mostly N,N-dimethyltryptamine (DMT), harmine, harmaline and tetrahydroharmine and some of their metabolites. An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered. PMID:26421727

  13. Acute Biphasic Effects of Ayahuasca.

    Science.gov (United States)

    Schenberg, Eduardo Ekman; Alexandre, João Felipe Morel; Filev, Renato; Cravo, Andre Mascioli; Sato, João Ricardo; Muthukumaraswamy, Suresh D; Yonamine, Maurício; Waguespack, Marian; Lomnicka, Izabela; Barker, Steven A; da Silveira, Dartiu Xavier

    2015-01-01

    Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important. Employing a combination of electroencephalogram (EEG) recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8-13 Hz) after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30-50 and 50-100 Hz, respectively) between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca's chemical compounds, mostly N,N-dimethyltryptamine (DMT), harmine, harmaline and tetrahydroharmine and some of their metabolites. An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered.

  14. 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.

  15. Human growth hormone and the development of osteochondritis dissecans lesions.

    Science.gov (United States)

    Hussain, Waqas M; Hussain, Haroon M; Hussain, Mohammed S; Ho, Sherwin S W

    2011-12-01

    No single etiology regarding the cause of osteochondritis dissecans (OCD) lesions is unanimously accepted. This report documents a novel case of multiple OCD lesions affecting the left knee and a solitary defect of the right elbow in a patient with acquired human growth hormone (hGH) deficiency and supplementation. hGH deficiency and hormone replacement may be related to the development of OCD lesions.

  16. 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.

  17. No effect of hole geometry in microfracture for talar osteochondral defects

    NARCIS (Netherlands)

    Kok, A.C.; Tuijthof, G.J.M.; den Dunnen, S.; van Tiel, J.; Siebelt, M.; Everts, V.; van Dijk, C.N.; Kerkhoffs, G.M.M.J.

    2013-01-01

    Background Débridement and bone marrow stimulation is an effective treatment option for patients with talar osteochondral defects. However, whether surgical factors affect the success of microfracture treatment of talar osteochondral defects is not well characterized. Questions/purposes We

  18. Injectable biphasic calcium phosphate bioceramic: The HYDROS concept.

    Science.gov (United States)

    Baroth, Serge; Bourges, Xavier; Goyenvalle, Eric; Aguado, Eric; Daculsi, Guy

    2009-01-01

    A new biphasic calcium phosphate ceramic material has been developed in our laboratory. It is composed of 60% of hydroxyapatite and 40% of beta-tricalcium phosphate, based on three granulometries (submicron, round microporous 80-200 mum and macro microporous 0.5-1 mm particles) and hydrated with water leading the formation of a putty filler for bone repair. Biocompatibility and osteogenicity were tested by filling femoral epiphyses critical size bone defect and lumbar muscles in rabbit. After 3, 6 and 12 weeks of implantation, explants were treated for histology. Results revealed the biocompatibility of the material and intensive resorption of the submicron particle fraction followed by important bone ingrowth whereas osteoconduction was provided by the larger particles.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Hydrogels for osteochondral repair based on photocrosslinkable carbamate dendrimers.

    Science.gov (United States)

    Degoricija, Lovorka; Bansal, Prashant N; Söntjens, Serge H M; Joshi, Neel S; Takahashi, Masaya; Snyder, Brian; Grinstaff, Mark W

    2008-10-01

    First generation, photocrosslinkable dendrimers consisting of natural metabolites (i.e., succinic acid, glycerol, and beta-alanine) and nonimmunogenic poly(ethylene glycol) (PEG) were synthesized divergently in high yields using ester and carbamate forming reactions. Aqueous solutions of these dendrimers were photocrosslinked with an eosin-based photoinitiator to afford hydrogels. The hydrogels displayed a range of mechanical properties based on their structure, generation size, and concentration in solution. All of the hydrogels showed minimal swelling characteristics. The dendrimer solutions were then photocrosslinked in situ in an ex vivo rabbit osteochondral defect (3 mm diameter and 10 mm depth), and the resulting hydrogels were subjected to physiologically relevant dynamic loads. Magnetic resonance imaging (MRI) showed the hydrogels to be fixated in the defect site after the repetitive loading regimen. The ([G1]-PGLBA-MA) 2-PEG hydrogel was chosen for the 6 month pilot in vivo rabbit study because this hydrogel scaffold could be prepared at low polymer weight (10 wt %) and possessed the largest compressive modulus of the 10% formulations, a low swelling ratio, and contained carbamate linkages, which are more hydrolytically stable than the ester linkages. The hydrogel-treated osteochondral defects showed good attachment in the defect site and histological analysis showed the presence of collagen II and glycosaminoglycans (GAGs) in the treated defects. By contrast, the contralateral unfilled defects showed poor healing and negligible GAG or collagen II production. Good mechanical properties, low swelling, good attachment to the defect site, and positive in vivo results illustrate the potential of these dendrimer-based hydrogels as scaffolds for osteochondral defect repair.

  1. Osteochondral destruction in pigmented villonodular synovitis during the clinical course.

    Science.gov (United States)

    Nishida, Yoshihiro; Tsukushi, Satoshi; Nakashima, Hiroatsu; Sugiura, Hideshi; Yamada, Yoshihisa; Urakawa, Hiroshi; Arai, Eisuke; Ishiguro, Naoki

    2012-02-01

    In pigmented villonodular synovitis (PVNS), some cases recur and progress to osteochondral destruction. The aim of our study was to clarify the occurrence of osteochondral destruction according to the location of PVNS during the clinical course. Seventy-two patients with PVNS (43 female, 29 male) with a mean age of 40 years (range 3-87 yrs) had been referred to our institutions. Factors influencing the occurrence of osteochondral destruction were investigated. Mean followup was 60 months (range 12-190 mo). Adjacent bone change occurred in 24 (42%) of 57 patients, who were evaluated at the time of the first consultation. Eight (89%) of 9 patients with hip lesions initially had bone lesions, significantly more frequently than those with other lesions (p = 0.038). Duration of symptoms was significantly correlated with the occurrence of bone lesions in diffuse knee lesions (p = 0.005). During followup, patients with location in the knee had a significantly higher incidence of osteoarthritic change (73%) compared to those with foot and ankle involvement (p = 0.027). Re-operation was more frequently required for knee lesions due to the high recurrence rate (32%). Patients who required re-operation had significantly more marked osteoarthritic change in knees (p = 0.001) during followup than those who did not. For PVNS arising in knees, repeated recurrences followed by re-operation resulted in the progression of osteoarthritic change. PVNS arising in hips, feet, and ankles developed bone lesions initially, probably due to the limited volume of these joints. The indications for re-operation for recurrent knee lesions require careful consideration regarding progression of osteoarthritic change.

  2. Knee hemarthros secondary to osteochondritis dissecans (König disease).

    Science.gov (United States)

    Guillén Astete, Carlos; Alva García, Patricia; Carpena Zafrilla, Maria; Medina Quiñones, Carmen

    2015-01-01

    A case is presented of a hemarthrosis associated with osteochondritis dissecans in a young man who arrived in the Emergency unit due to tender and swelling of his right knee one hour after a slightly rotational gesture of the lower limb. Many years before the patient suffered a sports injury in the same knee, but it was never assessed. Radiography studies showed bone fragments inside the synovial capsule, and the joint aspiration was compatible with hemarthrosis. A review of the available information of this uncommon condition is also presented.

  3. Repair of large osteochondral defects in rabbits using porous hydroxyapatite/collagen (HAp/Col) and fibroblast growth factor-2 (FGF-2).

    Science.gov (United States)

    Maehara, Hidetsugu; Sotome, Shinichi; Yoshii, Toshitaka; Torigoe, Ichiro; Kawasaki, Yuichi; Sugata, Yumi; Yuasa, Masato; Hirano, Masahiro; Mochizuki, Naomi; Kikuchi, Masanori; Shinomiya, Kenichi; Okawa, Atsushi

    2010-05-01

    Articular cartilage has a limited capacity for self-renewal. This article reports the development of a porous hydroxyapatite/collagen (HAp/Col) scaffold as a bone void filler and a vehicle for drug administration. The scaffold consists of HAp nanocrystals and type I atelocollagen. The purpose of this study was to investigate the efficacy of porous HAp/Col impregnated with FGF-2 to repair large osteochondral defects in a rabbit model. Ninety-six cylindrical osteochondral defects 5 mm in diameter and 5 mm in depth were created in the femoral trochlear groove of the right knee. Animals were assigned to one of four treatment groups: porous HAp/Col impregnated with 50 microl of FGF-2 at a concentration of 10 or 100 microg/ml (FGF10 or FGF100 group); porous HAp/Col with 50 microl of PBS (HAp/Col group); and no implantation (defect group). The defect areas were examined grossly and histologically. Subchondral bone regeneration was quantified 3, 6, 12, and 24 weeks after surgery. Abundant bone formation was observed in the HAp/Col implanted groups as compared to the defect group. The FGF10 group displayed not only the most abundant bone regeneration but also the most satisfactory cartilage regeneration, with cartilage presenting a hyaline-like appearance. These findings suggest that porous HAp/Col with FGF-2 augments the cartilage repair process.

  4. Salvage of a post-traumatic arthritic wrist using the scaphoid as an osteochondral graft.

    Science.gov (United States)

    Marcuzzi, A; Ozben, H; Russomando, A

    2014-09-01

    The authors describe a case of post-traumatic wrist arthritis with an osteochondral defect in the scaphoid fossa of the radius. The patient was treated with proximal row carpectomy, radial styloidectomy and reconstruction of the defect using the proximal half of the scaphoid as an autologous osteochondral graft. Pain relief was achieved while wrist motion and strength were improved. The carpal bones are a source of osteochondral grafts and can be used to expand the indications of motion-preserving wrist salvage procedures.

  5. ARTHROSCOPIC TREATMENT OF OSTEOCHONDRAL LESIONS OF THE TALUS

    Science.gov (United States)

    de Araujo, Mariana Korbage; de Cillo, Mario Sergio Paulillo; Bittar, Cinthia Kelly; Zabeu, José Luis Amin; Cezar, Caroliny Nociti Moreira

    2016-01-01

    ABSTRACT Objective: To assess pain and function of the ankle in patients with injuries up to 1.5 cm diameter by the American Orthopaedic Foot and Ankle Society (AOFAS) score after arthroscopic treatment. Methods: The AOFAS scale was applied before and after arthroscopy, as well as the degree of subjective satisfaction of ambulatory patients. Patients with type I osteochondral injuries, acute trauma, using plaster, presenting lesions in other joints of the lower limbs and cognitive impairment that would prevent the application of the satisfaction questionnaire were excluded from the study. Statistical analysis was performed using unpaired t test with Welch correction, Mann Whitney test, and ANOVA, with Kruskal Wallis test and Dun test, considering p value lower than 0.05. Results: There was an increased AOFAS scores after arthroscopic treatment in 52 (94.5%) patients. The mean values of AOFAS score in 55 patients was 77.32 ± 6.67 points preoperative and 93.10± 8.24 points postoperative, with a mean variation of 15.8 points, p0.05. Conclusion: Patients with stage II, III or IV osteochondral injuries of the talus of up to 1.5 cm diameter, whether medial or lateral, showed a significant improvement after arthroscopic treatment. Level of Evidence III, Retrospective Study. PMID:26997911

  6. Osteochondral tissue engineering: scaffolds, stem cells and applications

    Science.gov (United States)

    Nooeaid, Patcharakamon; Salih, Vehid; Beier, Justus P; Boccaccini, Aldo R

    2012-01-01

    Osteochondral tissue engineering has shown an increasing development to provide suitable strategies for the regeneration of damaged cartilage and underlying subchondral bone tissue. For reasons of the limitation in the capacity of articular cartilage to self-repair, it is essential to develop approaches based on suitable scaffolds made of appropriate engineered biomaterials. The combination of biodegradable polymers and bioactive ceramics in a variety of composite structures is promising in this area, whereby the fabrication methods, associated cells and signalling factors determine the success of the strategies. The objective of this review is to present and discuss approaches being proposed in osteochondral tissue engineering, which are focused on the application of various materials forming bilayered composite scaffolds, including polymers and ceramics, discussing the variety of scaffold designs and fabrication methods being developed. Additionally, cell sources and biological protein incorporation methods are discussed, addressing their interaction with scaffolds and highlighting the potential for creating a new generation of bilayered composite scaffolds that can mimic the native interfacial tissue properties, and are able to adapt to the biological environment. PMID:22452848

  7. 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

  8. 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.

  9. Bilateral osteochondritis dissecans of the elbow treated by Herbert screw fixation.

    Science.gov (United States)

    Inoue, G

    1991-09-01

    The case of a 15-year-old boy, a high-performance motocross rider, who developed bilateral osteochondritis dissecans of the elbow is described. Both lesions were successfully treated by Herbert screw internal fixation.

  10. A cadaveric analysis of contact stress restoration after osteochondral transplantation of a cylindrical cartilage defect.

    NARCIS (Netherlands)

    Kock, N.B.; Smolders, J.M.; Susante, J.L.C. van; Buma, P.; Kampen, A. van; Verdonschot, N.J.J.

    2008-01-01

    Osteochondral transplantation is a successful treatment for full-thickness cartilage defects, which without treatment would lead to early osteoarthritis. Restoration of surface congruency and stability of the reconstruction may be jeopardized by early mobilization. To investigate the biomechanical e

  11. 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.

  12. [Osteochondritis dissecans of the femoral condyles: report of 892 cases].

    Science.gov (United States)

    Lefort, G; Moyen, B; Beaufils, P; de Billy, B; Breda, R; Cadilhac, C; Clavert, J-M; Djian, P; Fenoll, B; Giacomelli, M-C; Gicquel, P; Gicquel-Schlemmer, B; Journeau, P; Karger, C; Laptoiu, D; Lefort, G; Mainard-Simard, L; Moyen, B; Negreanu, I; Prové, S; Robert, H; Thaunat, M; Versier, G

    2006-09-01

    Osteochondritis rarely involves the femoral condyles. Discovery in this localization raises several questions concerning the nature of the articular cartilage, the potential for spontaneous healing, and, in the event of a free fragment, the outcome after its loss or repair. This multicentric study included 892 pediatric and adult cases, the cutoff between two series being defined by fusion of the inferior growth plate. We excluded medical or surgical osteochondritis, cases involving the patella, osteochondral fractures, juvenile polyosteochondrosis, adult osteonecrosis, and osteochondritis beginning after the age of 50 years. Mean age at diagnosis was 16.5 years. Mean age at treatment onset was 22 years. Pain was the predominant symptom. 80% of cases were unilateral and 70% involved the medial condyle. The anatomic lesions were different in adults, showing more advanced degradation. At diagnosis, Bedouelle stages Ia and IIb constituted 80% of the cases observed among children while in adults, 66% were Bedouelle stages IIb to IV. Outcome was very good for the majority of children with Hughston clinical stage 4 while half of the x-rays were Hughston stage 3 and 4. There were thus a large percentage of children with abnormal xrays whose disease history was not yet terminated. In the adult series, the percentages of Hughston 3 and 4 was about the same as clinically. The x-rays were rarely perfectly normal since half of the clinical stage 3 patients were noted in stage 4. An abnormal x-ray with a very good clinical presentation was observed in a very large proportion of patients. It is difficult to interpret the plain x-ray and identify patients with a potentially unfavorable prognosis. We defined three radiographic classes: defect, nodule and empty notch. The Bedouelle classification uses information from all available explorations, particularly MRI and arthroscopy. Numerous therapeutic methods are used. Interruption of sports activities is the first intention

  13. Metal separations using aqueous biphasic partitioning systems

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, D.J.; Zaslavsky, B.; Rollins, A.N.; Vojta, Y.; Gartelmann, J.; Mego, W. [Argonne National Lab., IL (United States). Chemical Technology Div.

    1996-05-01

    Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that the authors have studied are generated by combining an aqueous salt solution with an aqueous polymer solution. They have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. They have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). In this report they review the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation.

  14. Biphase sinusoidal oscillator based on negative resistor.

    Science.gov (United States)

    Bayard, Jean

    2010-06-01

    This paper describes a biphase sinusoidal generator which provides two signals: v(ref)=V(M) sin(omegat) and v(out)=V(M) sin(omegat+DeltaPhi), where DeltaPhi is in the range 0, pi/2 or -pi/2, 0 and is not dependent on the frequency value. It is based on a negative resistor and it requires very few components. SPICE simulations and measurements on an experimental setup confirm the theoretical analysis.

  15. 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 algorithm...... 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......,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...

  16. Additive manufacturing for in situ repair of osteochondral defects

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Daniel L; Lipton, Jeffrey I; Bonassar, Lawrence J; Lipson, Hod, E-mail: dlc44@cornell.ed, E-mail: jil26@cornell.ed, E-mail: lb244@cornell.ed, E-mail: hod.lipson@cornell.ed [Cornell University, Mechanical and Aerospace Engineering, Ithaca, NY (United States)

    2010-09-15

    Tissue engineering holds great promise for injury repair and replacement of defective body parts. While a number of techniques exist for creating living biological constructs in vitro, none have been demonstrated for in situ repair. Using novel geometric feedback-based approaches and through development of appropriate printing-material combinations, we demonstrate the in situ repair of both chondral and osteochondral defects that mimic naturally occurring pathologies. A calf femur was mounted in a custom jig and held within a robocasting-based additive manufacturing (AM) system. Two defects were induced: one a cartilage-only representation of a grade IV chondral lesion and the other a two-material bone and cartilage fracture of the femoral condyle. Alginate hydrogel was used for the repair of cartilage; a novel formulation of demineralized bone matrix was used for bone repair. Repair prints for both defects had mean surface errors less than 0.1 mm. For the chondral defect, 42.8 {+-} 2.6% of the surface points had errors that were within a clinically acceptable error range; however, with 1 mm path planning shift, an estimated {approx}75% of surface points could likely fall within the benchmark envelope. For the osteochondral defect, 83.6 {+-} 2.7% of surface points had errors that were within clinically acceptable limits. In addition to implications for minimally invasive AM-based clinical treatments, these proof-of-concept prints are some of the only in situ demonstrations to-date, wherein the substrate geometry was unknown a priori. The work presented herein demonstrates in situ AM, suggests potential biomedical applications and also explores in situ-specific issues, including geometric feedback, material selection and novel path planning techniques.

  17. 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.

  18. In vitro study on biomineralization of biphasic calcium phosphate biocomposite crosslinked with hydrolysable tannins of Terminalia chebula

    Indian Academy of Sciences (India)

    G Krithiga; Antaryami Jena; P Selvamani; T P Sastry

    2011-06-01

    In this study, we report the preparation of a bone graft material, having cylindrical shape, containing biphasic calcium phosphate (BCP), gelatin (G), chitosan (C) and Terminalia chebula (TC) extract. TC extract was used as a crosslinker that gives stability to bone graft when it is placed in SBF. The graft was stable in the SBF solution for 21 days and FTIR, SEM, EDX and thermogravimetric studies revealed the ossification of the implant.

  19. 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

    2015-09-01

    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.

  20. 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.

  1. O uso do transplante osteocondral a fresco no tratamento das lesões osteocondrais do joelho Use of fresh osteochondral transplants for treating osteochondral knee lesions

    Directory of Open Access Journals (Sweden)

    Luís Eduardo Passarelli Tírico

    2012-01-01

    Full Text Available O tratamento das lesões condrais e osteocondrais do joelho em pacientes jovens ainda permanece um desafio para os ortopedistas. As técnicas de reparo atualmente disponíveis no Brasil, como o desbridamento, microfraturas e transplante osteocondral autólogo são insuficientes nos tratamentos de lesões condrais e osteocondrais grandes. O transplante osteocondral homólogo a fresco (TOF na articulação do joelho vem sendo usado nos Estados Unidos com excelentes resultados. Este artigo tem o intuito de revisar a ciência básica, indicações, técnicas cirúrgicas, possíveis complicações e descrever a técnica de transplante osteocondral homólogo a fresco na articulação do joelho realizada no Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da Universidade de São Paulo.Treatment of chondral and osteochondral knee lesions in young patients remains a challenge for orthopedic surgeons. The repair techniques currently available in Brazil, such as debridement, microfracture and autologous osteochondral transplantation are insufficient for treating large chondral and osteochondral lesions. Fresh homologous osteochondral transplants have been used in the knee joint in the United States with excellent results. This article had the aims of reviewing the basic science, indi cations, surgical techniques and possible complications and describing the technique of fresh homologous osteochondral transplantation in the knee joint, performed in the Institute of Orthopedics and Traumatology, Hospital das Clinicas, Univer sity of São Paulo.

  2. Retrospective Cohort Study of 207 Cases of Osteochondritis Dissecans of the Knee

    Science.gov (United States)

    Green, Daniel W.; Arbucci, John; Silberman, Jason; Luderowski, Eva; Uppstrom, Tyler J.; Nguyen, Joseph; Tuca, Maria

    2016-01-01

    Objectives: Describe the clinical characteristics, image findings, and outcomes of patients with juvenile osteochondritis dissecans (JOCD) of the knee. To our knowledge, this is the largest single-surgeon cohort of JOCD patients. Methods: Retrospective cohort study of knee JOCD patients assessed by a single pediatric orthopaedic surgeon at a tertiary care center between 2005-2015. All diagnoses were confirmed by magnetic resonance imaging (MRI). Patients with patellar dislocations or osteochondral fractures were excluded. Demographic data, sports played, comorbidities, surgical procedures, and clinical data were extracted from charts. Images were analyzed to identify the location and size of lesions. Chi-square or Fisher’s exact tests were used to compare discrete variables, and Mann-Whitney U and Kruskal Wallis tests to compare continuous variables between groups. P-values of <0.05 were considered significant. Results: Sample consisted of 180 patients (207 knees), 124 boys and 56 girls. Average age at diagnosis was 12.8 years (7.5-17.5). Majority were active in sports (80.8%), primary soccer (36.7%) and basketball (29.4%). JOCD was present bilaterally in 27 patients (15%), 14 knees had bifocal OCD (6.8%), and only 1 patient had bifocal lesions in both knees. Most common location was medial femoral condyle (56.3%) followed by lateral femoral condyle (23.1%), trochlea (11.4%), patella (9%), and tibia (0.5%). In the sagittal view, most common location was the middle third of the condyles (48.7%). Surgery was performed in 72 knees (34.8%), with an average age at surgery of 14.1 years (9.3-18.1). Bilateral JOCD was present in 13 surgical patients (18.8%), but only 3 patients had bilateral surgery. Two operative patients had bifocal JOCD (2.7%) and surgery on both lesions. Location distribution did not differ between surgical and non-surgical lesions. The average normalized area of non-surgical JOCD lesions was 6.8 (0.1-18), whereas surgical lesions averaged a

  3. A Framework for the Modelling of Biphasic Reacting Systems

    DEFF Research Database (Denmark)

    Anantpinijwatna, Amata; Sin, Gürkan; O’Connell, John P.

    2014-01-01

    Biphasic reacting systems have a broad application range from organic reactions in pharmaceutical and agro-bio industries to CO 2 capture. However, mathematical modelling of biphasic reacting systems is a formidable challenge due to many phenomena underlying the process such as chemical equilibri...... systems: a PTC-based reaction system and pseudo-PTC system....

  4. Biphasic calcium phosphate–casein bone graft fortified with Cassia occidentalis for bone tissue engineering and regeneration

    Indian Academy of Sciences (India)

    B Santhosh Kumar; T Hemalatha; R Deepachitra; R Narasimha Raghavan; P Prabu; T P Sastry

    2015-02-01

    Research on traditional herbs is gaining momentum owing to their potent medical properties, among which Cassia occidentalis (CO) is a promising herb, with osteogenic potential. The study investigates the efficacy of CO extract incorporated biphasic calcium phosphate as an osteoinductive material. Prepared bone implants were characterized physico-chemically using FT-IR, TGA, XRD, SEM and EDX. The implants were analysed further for mechanical and biological properties. The results revealed that CO extract-incorporated bone implants possessed better compression strength and it was able to induce proliferation and enhance alkaline phosphatase activity in SaOS-2 cells. The implant proves to be promising for bone tissue engineering, and hence it demands further in vivo evaluation.

  5. 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

  6. AQUEOUS BIPHASE EXTRACTION FOR PROCESSING OF FINE COAL

    Energy Technology Data Exchange (ETDEWEB)

    K. Osseo-Asare; X. Zeng

    2002-01-01

    The objective of this research project is to develop an aqueous biphase extraction process for the treatment of fine coals. Aqueous biphase extraction is an advanced separation technology that relies on the ability of an aqueous system consisting of a water-soluble polymer and another component, e.g., another polymer, an inorganic salt, or a nonionic surfactant, to separate into two immiscible aqueous phases. The principle behind the partition of solid particles in aqueous biphase systems is the physicochemical interaction between the solid surface and the surrounding liquid solution. In order to remove sulfur and mineral matter from fine coal with aqueous biphasic extraction, it is necessary to know the partitioning behavior of coal, as well as the inorganic mineral components. Therefore, in this research emphasis was placed on the partitioning behavior of fine coal particles as well as model fine inorganic particles in aqueous biphase systems.

  7. The Wnt11 Signaling Pathway in Potential Cellular EMT and Osteochondral Differentiation Progression in Nephrolithiasis Formation.

    Science.gov (United States)

    He, Deng; Lu, Yuchao; Hu, Henglong; Zhang, Jiaqiao; Qin, Baolong; Wang, Yufeng; Xing, Shuai; Xi, Qilin; Wang, Shaogang

    2015-07-17

    The molecular events leading to nephrolithiasis are extremely complex. Previous studies demonstrated that calcium and transforming growth factor-β1 (TGF-β1) may participate in the pathogenesis of stone formation, but the explicit mechanism has not been defined. Using a self-created genetic hypercalciuric stone-forming (GHS) rat model, we observed that the increased level of serous/uric TGF-β1 and elevated intracellular calcium in primary renal tubular epithelial cells (PRECs) was associated with nephrolithiasis progression in vivo. In the setting of high calcium plus high TGF-β1 in vitro, PRECs showed great potential epithelial to mesenchymal transition (EMT) progression and osteochondral differentiation properties, representing the multifarious increased mesenchymal and osteochondral phenotypes (Zeb1, Snail1, Col2A1, OPN, Sox9, Runx2) and decreased epithelial phenotypes (E-cadherin, CK19) bythe detection of mRNAs and corresponding proteins. Moreover, TGF-β-dependent Wnt11 knockdown and L-type Ca2+ channel blocker could greatly reverse EMT progression and osteochondral differentiation in PRECs. TGF-β1 alone could effectively promote EMT, but it had no effect on osteochondral differentiation in NRK cells (Rat kidney epithelial cell line). Stimulation with Ca2+ alone did not accelerate differentiation of NRK. Co-incubation of extracellular Ca2+ and TGF-β1 synergistically promotes EMT and osteochondral differentiation in NRK control cells. Our data supplied a novel view that the pathogenesis of calcium stone development may be associated with synergic effects of TGF-β1 and Ca2+, which promote EMT and osteochondral differentiation via Wnt11 and the L-type calcium channel.

  8. The Wnt11 Signaling Pathway in Potential Cellular EMT and Osteochondral Differentiation Progression in Nephrolithiasis Formation

    Directory of Open Access Journals (Sweden)

    Deng He

    2015-07-01

    Full Text Available The molecular events leading to nephrolithiasis are extremely complex. Previous studies demonstrated that calcium and transforming growth factor-β1 (TGF-β1 may participate in the pathogenesis of stone formation, but the explicit mechanism has not been defined. Using a self-created genetic hypercalciuric stone-forming (GHS rat model, we observed that the increased level of serous/uric TGF-β1 and elevated intracellular calcium in primary renal tubular epithelial cells (PRECs was associated with nephrolithiasis progression in vivo. In the setting of high calcium plus high TGF-β1 in vitro, PRECs showed great potential epithelial to mesenchymal transition (EMT progression and osteochondral differentiation properties, representing the multifarious increased mesenchymal and osteochondral phenotypes (Zeb1, Snail1, Col2A1, OPN, Sox9, Runx2 and decreased epithelial phenotypes (E-cadherin, CK19 bythe detection of mRNAs and corresponding proteins. Moreover, TGF-β-dependent Wnt11 knockdown and L-type Ca2+ channel blocker could greatly reverse EMT progression and osteochondral differentiation in PRECs. TGF-β1 alone could effectively promote EMT, but it had no effect on osteochondral differentiation in NRK cells (Rat kidney epithelial cell line. Stimulation with Ca2+ alone did not accelerate differentiation of NRK. Co-incubation of extracellular Ca2+ and TGF-β1 synergistically promotes EMT and osteochondral differentiation in NRK control cells. Our data supplied a novel view that the pathogenesis of calcium stone development may be associated with synergic effects of TGF-β1 and Ca2+, which promote EMT and osteochondral differentiation via Wnt11 and the L-type calcium channel.

  9. Chondroblastoma of the Knee Treated with Resection and Osteochondral Allograft Reconstruction

    Directory of Open Access Journals (Sweden)

    Judd Fitzgerald

    2014-01-01

    Full Text Available Case. This case report describes the operative management of 16-year-old male with a symptomatic chondroblastoma of the distal femur with breach of the chondral surface. Following appropriate imaging and core needle biopsy, the diagnosis was confirmed histologically. The patient then underwent intralesional curettage and osteochondral allograft reconstruction of the defect. At one-year follow-up the patient was pain-free and has obtained excellent range of motion. There is radiographic evidence of allograft incorporation and no evidence of local recurrence. Conclusion. Osteochondral allograft reconstruction is an effective option following marginal resection and curettage of chondroblastoma involving the chondral surface of the distal femur.

  10. Chondroblastoma of the knee treated with resection and osteochondral allograft reconstruction.

    Science.gov (United States)

    Fitzgerald, Judd; Broehm, Cory; Chafey, David; Treme, Gehron

    2014-01-01

    Case. This case report describes the operative management of 16-year-old male with a symptomatic chondroblastoma of the distal femur with breach of the chondral surface. Following appropriate imaging and core needle biopsy, the diagnosis was confirmed histologically. The patient then underwent intralesional curettage and osteochondral allograft reconstruction of the defect. At one-year follow-up the patient was pain-free and has obtained excellent range of motion. There is radiographic evidence of allograft incorporation and no evidence of local recurrence. Conclusion. Osteochondral allograft reconstruction is an effective option following marginal resection and curettage of chondroblastoma involving the chondral surface of the distal femur.

  11. Breast Implants

    Science.gov (United States)

    ... Medical Procedures Implants and Prosthetics Breast Implants Breast Implants Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Breast implants are medical devices that are implanted under the ...

  12. [The clinical practice guidelines of the Sociedad Española de Cardiología on the automatic implantable defibrillator].

    Science.gov (United States)

    Pérez-Villacastín, J; Carmona Salinas, J R; Hernández Madrid, A; Marín Huerta, E; Merino Llorens, J L; Ormaetxe Merodio, J; Moya i Mitjans, A

    1999-12-01

    Since the first implantation in man in 1980 implantable cardioverter defibrillator technology has greatly improved and the number of devices implanted has increased considerably every year. Non thoracotomy lead systems and biphasic shocks are now the approach of choice, offering an almost 100% success rate. This document reviews the recommendations for qualification of personnel and for the centres implanting and carrying out follow-ups on defibrillators. The current indications for the implantation of implantable cardioverter defibrillator are also addressed.

  13. A new building block: costo-osteochondral graft for intra-articular incongruity after distal radius fracture.

    Science.gov (United States)

    Tang, Chris Yuk Kwan; Fung, Boris; Poon, T L; Fok, Margaret

    2014-01-01

    Even with the invention of locking plates, intra-articular fractures of distal radius with extreme comminution remain a challenge for orthopaedic surgeons. Osteochondral graft is a potential choice to reconstruct the articular defect. We report a patient who had a fracture of distal radius with costo-osteochondral graft for articular reconstruction which has not yet been described in the English literature. At nine-year follow-up, he was pain free and had full range of movement of the wrist. The authors suggest that costo-osteochondral graft could be an option with satisfactory result.

  14. Osteochondral lesion depth on MRI can help predict the need for a sandwich procedure.

    Science.gov (United States)

    Nizak, R; Bekkers, J; de Jong, P A; Witkamp, T; Luijkx, T; Saris, D

    2017-05-01

    Autologous subchondral bone grafting in combination with autologous chondrocyte implantation (ACI) (sandwich procedure) is a well-accepted procedure for the treatment of osteochondral lesions of the knee. This requires a different surgical technique and preoperative planning compared to ACI alone. In addition, pain from bone marrow donor site locations can be expected and should be part of patient consent and expectations. This study evaluates whether the MRI made as part of the standard preoperative cartilage patient work up has the diagnostic accuracy to predict the need for a sandwich procedure. Retrospectively, 185 preoperative MRI scans (PD and T2 sequences) of patients planned for ACI were included. The integrity of the subchondral bone and lamina was scored by four different observers (3 radiologists, and 1 orthopaedic resident). The depth of the defect was measured perpendicular from articulating surface to the bottom of the bony lesion. The area under the curve (AUC) for subchondral defect on MRI (i.e. lamina or bone defect or expert impression), depth measurements and eventual sandwich procedure were calculated. Also inter-observer Kappa values were determined. The AUCs for lamina (0.74-0.80) and bone defect (0.73-0.79) were fair and inter-observer Kappas ranged from 0.49 to 0.76, indicating a moderate-good inter-observer agreement and moderate prediction of the need for a sandwich procedure based on the presence of lamina and or subchondral bone defect on MRI. However, depth measurements resulted in an AUC of 0.90 (95% CI: 0.84-0.95,) with an optimal cut-off point at 6.5mm depth of the lesion (90% sensitivity, 80% specificity) to predict the need for a sandwich procedure. Ours is the first study examining MRI as a diagnostic tool in predicting the need for a sandwich procedure. Our results show that the integrity of the subchondral layer on MRI has a moderate role in predicting the need for an eventual autologous bone graft to augment ACI whereas in our

  15. Evidence of a major gene from Bayesian segregation analyses of liability to osteochondral diseases in pigs

    NARCIS (Netherlands)

    Kadarmideen, H.N.; Janss, L.L.G.

    2005-01-01

    Bayesian segregation analyses were used to investigate the mode of inheritance of osteochondral lesions (osteochondrosis, OC) in pigs. Data consisted of 1163 animals with OC and their pedigrees included 2891 animals. Mixed-inheritance threshold models (MITM) and several variants of MITM, in conjunct

  16. 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 tal

  17. Design of a multiphase osteochondral scaffold. I. Control of chemical composition.

    Science.gov (United States)

    Lynn, Andrew K; Best, Serena M; Cameron, Ruth E; Harley, Brendan A; Yannas, Ioannis V; Gibson, Lorna J; Bonfield, William

    2010-03-01

    This is the first in a series of articles that describe the design and development of a family of osteochondral scaffolds based on collagen-glycosaminoglycan (collagen-GAG) and calcium phosphate technologies, engineered for the regenerative repair of defects in articular cartilage. The osteochondral scaffolds consist of two layers: a mineralized type I collagen-GAG scaffold designed to regenerate the underlying subchondral bone and a nonmineralized type II collagen-GAG scaffold designed to regenerate cartilage. The subsequent articles in this series describe the fabrication and properties of a mineralized scaffold as well as a two-layer (one mineralized, the other not) osteochondral scaffold for regeneration of the underlying bone and cartilage, respectively. This article describes a technology through which the chemical composition-particularly the calcium phosphate mass fraction-of triple coprecipitated nanocomposites of collagen, glycosaminoglycan, and calcium phosphate can be accurately and reproducibly varied without the need for titrants or other additives. Here, we describe how the mineral:organic ratio can be altered over a range that includes that for articular cartilage (0 wt % mineral) and for bone (75 wt % mineral). This technology achieves the objective of mimicking the composition of two main tissue types found in articular joints, with particular emphasis on the osseous compartment of an osteochondral scaffold. Exclusion of titrants avoids the formation of potentially harmful contaminant phases during freeze-drying steps crucial for scaffold fabrication, ensuring that the potential for binding growth factors and drugs is maintained.

  18. A cadaveric analysis of contact stress restoration after osteochondral transplantation of a cylindrical cartilage defect.

    Science.gov (United States)

    Kock, Niels B; Smolders, José M H; van Susante, Job L C; Buma, Pieter; van Kampen, Albert; Verdonschot, Nico

    2008-05-01

    Osteochondral transplantation is a successful treatment for full-thickness cartilage defects, which without treatment would lead to early osteoarthritis. Restoration of surface congruency and stability of the reconstruction may be jeopardized by early mobilization. To investigate the biomechanical effectiveness of osteochondral transplantation, we performed a standardized osteochondral transplantation in eight intact human cadaver knees, using three cylindrical plugs on a full-thickness cartilage defect, bottomed on one condyle, unbottomed on the contralateral condyle. Surface pressure measurements with Tekscan pressure transducers were performed after five conditions. In the presence of a defect the border contact pressure of the articular cartilage defect significantly increased to 192% as compared to the initially intact joint surface. This was partially restored with osteochondral transplantation (mosaicplasty), as the rim stress subsequently decreased to 135% of the preoperative value. Following weight bearing motion two out of eight unbottomed mosaicplasties showed subsidence of the plugs according to Tekscan measurements. This study demonstrates that a three-plug mosaicplasty is effective in restoring the increased border contact pressure of a cartilage defect, which may postpone the development of early osteoarthritis. Unbottomed mosaicplasties may be more susceptible for subsidence below flush level after (unintended) weight bearing motion.

  19. Thermal stability of hydroxyapatite in biphasic calcium phosphate ceramics

    CSIR Research Space (South Africa)

    Nilen, RWN

    2008-04-01

    Full Text Available Biphasic calcium phosphate ceramics (BCP) comprising a mix of non-resorbable hydroxyapatite (HA) and resorbable b-tricalcium phosphate (b-TCP) are particularly suitable materials for synthetic bone substitute applications. In this study, HA...

  20. Autologous cartilage fragments in a composite scaffold for one stage osteochondral repair in a goat model

    Directory of Open Access Journals (Sweden)

    A Marmotti

    2013-08-01

    Full Text Available We propose a culture-free approach to osteochondral repair with minced autologous cartilage fragments loaded onto a scaffold composed of a hyaluronic acid (HA-derived membrane, platelet-rich fibrin matrix (PRFM and fibrin glue. The aim of the study was to demonstrate in vitro the outgrowth of chondrocytes from cartilage fragments onto this scaffold and, in vivo, the formation of functional repair tissue in goat osteochondral defects. Two sections were considered: 1 in vitro: minced articular cartilage from goat stifle joints was loaded onto scaffolds, cultured for 1 or 2 months, and then evaluated histologically and immunohistochemically; 2 in vivo: 2 unilateral critically-sized trochlear osteochondral defects were created in 15 adult goats; defects were treated with cartilage fragments embedded in the scaffold (Group 1, with the scaffold alone (Group 2, or untreated (Group 3. Repair processes were evaluated morphologically, histologically, immunohistochemically and biomechanically at 1, 3, 6 and 12 months. We found that in vitro, chondrocytes from cartilage fragments migrated to the scaffold and, at 2 months, matrix positive for collagen type II was observed in the constructs. In vivo, morphological and histological assessment demonstrated that cartilage fragment-loaded scaffolds led to the formation of functional hyaline-like repair tissue. Repair in Group 1 was superior to that of control groups, both histologically and mechanically. Autologous cartilage fragments loaded onto an HA/PRFM/fibrin glue scaffold provided a viable cell source and allowed for an improvement of the repair process of osteochondral defects in a goat model, representing an effective alternative for one-stage repair of osteochondral lesions.

  1. Acute encephalopathy with biphasic seizures and late reduced diffusion

    Directory of Open Access Journals (Sweden)

    Saroj S Yadav

    2013-01-01

    Full Text Available Acute encephalopathy with biphasic seizures and reduced diffusion (AESD is a syndrome of encephalopathy characterized by biphasic seizures and altered consciousness in the acute stage followed in the subacute stage by restricted diffusion in the subcortical white matter on magnetic resonance imaging. The etiology of AESD has been attributed to viral infection like influenza A and human herpes virus 6. The exact pathogenesis of AESD is uncertain. Here we report a case of AESD, diagnosed based on clinicoradiological correlation.

  2. Intervertebral Disc Tissue Engineering with Natural Extracellular Matrix-Derived Biphasic Composite Scaffolds.

    Directory of Open Access Journals (Sweden)

    Baoshan Xu

    Full Text Available Tissue engineering has provided an alternative therapeutic possibility for degenerative disc diseases. However, we lack an ideal scaffold for IVD tissue engineering. The goal of this study is to fabricate a novel biomimetic biphasic scaffold for IVD tissue engineering and evaluate the feasibility of developing tissue-engineered IVD in vitro and in vivo. In present study we developed a novel integrated biphasic IVD scaffold using a simple freeze-drying and cross-linking technique of pig bone matrix gelatin (BMG for the outer annulus fibrosus (AF phase and pig acellular cartilage ECM (ACECM for the inner nucleus pulposus (NP phase. Histology and SEM results indicated no residual cells remaining in the scaffold that featured an interconnected porous microstructure (pore size of AF and NP phase 401.4 ± 13.1 μm and 231.6 ± 57.2 μm, respectively. PKH26-labeled AF and NP cells were seeded into the scaffold and cultured in vitro. SEM confirmed that seeded cells could anchor onto the scaffold. Live/dead staining showed that live cells (green fluorescence were distributed in the scaffold, with no dead cells (red fluorescence being found. The cell-scaffold constructs were implanted subcutaneously into nude mice and cultured for 6 weeks in vivo. IVD-like tissue formed in nude mice as confirmed by histology. Cells in hybrid constructs originated from PKH26-labeled cells, as confirmed by in vivo fluorescence imaging system. In conclusion, the study demonstrates the feasibility of developing a tissue-engineered IVD in vivo with a BMG- and ACECM-derived integrated AF-NP biphasic scaffold. As well, PKH26 fluorescent labeling with in vivo fluorescent imaging can be used to track cells and analyse cell--scaffold constructs in vivo.

  3. Osteochondritis Dissecans of the Humeral Capitellum in Young Athletes

    Science.gov (United States)

    Kajiyama, Shiro; Muroi, Satoshi; Sugaya, Hiroyuki; Takahashi, Norimasa; Matsuki, Keisuke; Kawai, Nobuaki; Osaki, Makoto

    2017-01-01

    Background: Osteochondritis dissecans (OCD) lesions are often observed in the humeral capitellum both in young baseball players and gymnasts. It is generally believed that capitellar OCD in baseball players can be seen on an anteroposterior (AP) radiograph with the elbow in 45° of flexion. However, the mechanism of injury seems to be different in baseball players and gymnasts. Repetitive valgus overload with the elbow in flexion is believed to be the cause of capitellar OCD lesions in baseball players, whereas weightbearing with the elbow in extension may be the cause of OCD in gymnasts. Purpose: To determine the difference in capitellar OCD location between baseball players and gymnasts and to propose the optimal AP radiographic angle of the elbow for visualization of early-stage OCD lesions in adolescent gymnasts. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Subjects consisted of 95 baseball players (95 elbows) and 21 gymnasts (24 elbows) with a mean age of 13.7 years (range, 11-18 years). To localize the lesion, inclination of the affected area in the humeral capitellum against the humeral axis was investigated using sagittal computed tomography images of the elbow. The inclination angle was defined as the angle between the long axis of the humerus and the line perpendicular to a line that connected the anterior and posterior margin of the lesion. The inclination angle in each group was compared and statistically analyzed. Results: The mean inclination angle was 57.6° ± 10.7° in baseball players and 28.0° ± 10.7° in gymnasts. Capitellar OCD lesions were located more anterior in baseball players when compared with gymnasts (P < .01). Conclusion: Due to differences in applied stress, capitellar OCD lesions in baseball players were located more anteriorly compared with those seen in gymnasts. Therefore, although AP radiographs with the elbow in 45° of flexion are optimal for detecting OCD lesions in baseball players, radiographs with

  4. Penile Implants

    Science.gov (United States)

    ... the discussion with your doctor. Types of penile implants There are two main types of penile implants: ... might help reduce the risk of infection. Comparing implant types When choosing which type of penile implant ...

  5. A histomorphometric and micro-computed tomography study of bone regeneration in the maxillary sinus comparing biphasic calcium phosphate and deproteinized cancellous bovine bone in a human split-mouth model

    NARCIS (Netherlands)

    de Lange, G.L.; Overman, J.R.; Farre-Guasch, E.; Korstjens, C.M.; Hartman, B.; Langenbach, G.E.J.; van Duin, M.A.; Klein-Nulend, J.

    2014-01-01

    Objective The gain of mineralized bone was compared between deproteinized bovine bone allograft (DBA) and biphasic calcium phosphate (BCP) for dental implant placement. Study Design Five patients with atrophic maxillae underwent bilateral sinus elevation with DBA (Bio-Oss) and BCP (Straumann BoneCer

  6. Autologous Osteochondral Transplantation for Osteochondral Lesions of the Talus: Does Previous Bone Marrow Stimulation Negatively Affect Clinical Outcome?

    Science.gov (United States)

    Ross, Andrew W; Murawski, Christopher D; Fraser, Ethan J; Ross, Keir A; Do, Huong T; Deyer, Timothy W; Kennedy, John G

    2016-07-01

    To determine if functional outcomes and magnetic resonance imaging (MRI) outcomes were significantly different between patients receiving primary autologous osteochondral transplantation (AOT) and patients receiving secondary AOT surgery after failed microfracture. A group of 76 patients enrolled into the Foot and Ankle Service between 2006 and 2012 was retrospectively analyzed. Patient-reported outcomes were evaluated in 76 patients using the Foot and Ankle Outcome Score (FAOS). Superficial and deep tissues at the repaired defect site, as well as the adjacent normal cartilage, were analyzed using quantitative T2 mapping MRI. Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) allowed for morphological evaluation of the repair tissue. The mean clinical follow-up time was 51 ± 23 months (range, 12 to 97 months), and the mean MRI follow-up time was 26 months (range, 24 to 36 months). Twenty-two patients received primary AOT and 54 received secondary AOT after failed microfracture. Patient characteristics between groups were similar with regard to age, gender, lesion size, and follow-up time. The mean postoperative FAOS was 10 points higher in the primary AOT group (83.2 ± 17.0) compared with the secondary AOT group (72.4 ± 19.4) (P = .01). Regression analysis showed that secondary AOT patients preoperative to postoperative change in FAOS was 9 points lower than in primary AOT patients after adjustment for age, preoperative FAOS, and lesion size (P = .045). The mean MOCART score, superficial T2 and deep T2 values, and the difference between normal and repair cartilage T2 values were not significantly different between groups. Lesion size was negatively correlated with MOCART scores (ρ = -0.2, P = .04), but positively correlated with difference in T2 values between repair and adjacent normal cartilage in the superficial layer (ρ = 0.3, P = .045). Primary AOT shows better functional outcomes compared with secondary AOT after failed

  7. Comparative repair capacity of knee osteochondral defects using regenerated silk fiber scaffolds and fibrin glue with/without autologous chondrocytes during 36 weeks in rabbit model.

    Science.gov (United States)

    Kazemnejad, Somaieh; Khanmohammadi, Manijeh; Mobini, Sahba; Taghizadeh-Jahed, Masoud; Khanjani, Sayeh; Arasteh, Shaghayegh; Golshahi, Hannaneh; Torkaman, Giti; Ravanbod, Roya; Heidari-Vala, Hamed; Moshiri, Ali; Tahmasebi, Mohammad-Naghi; Akhondi, Mohammad-Mehdi

    2016-06-01

    The reconstruction capability of osteochondral (OCD) defects using silk-based scaffolds has been demonstrated in a few studies. However, improvement in the mechanical properties of natural scaffolds is still challengeable. Here, we investigate the in vivo repair capacity of OCD defects using a novel Bombyx mori silk-based composite scaffold with great mechanical properties and porosity during 36 weeks. After evaluation of the in vivo biocompatibility and degradation rate of these scaffolds, we examined the effectiveness of these fabricated scaffolds accompanied with/without autologous chondrocytes in the repair of OCD lesions of rabbit knees after 12 and 36 weeks. Moreover, the efficiency of these scaffolds was compared with fibrin glue (FG) as a natural carrier of chondrocytes using parallel clinical, histopathological and mechanical examinations. The data on subcutaneous implantation in mice showed that the designed scaffolds have a suitable in vivo degradation rate and regenerative capacity. The repair ability of chondrocyte-seeded scaffolds was typically higher than the scaffolds alone. After 36 weeks of implantation, most parts of the defects reconstructed by chondrocytes-seeded silk scaffolds (SFC) were hyaline-like cartilage. However, spontaneous healing and filling with a scaffold alone did not eventuate in typical repair. We could not find significant differences between quantitative histopathological and mechanical data of SFC and FGC. The fabricated constructs consisting of regenerated silk fiber scaffolds and chondrocytes are safe and suitable for in vivo repair of OCD defects and promising for future clinical trial studies.

  8. Biphasic catalysis in water/carbon dioxide micellar systems

    Science.gov (United States)

    Jacobson, Gunilla B.; Tumas, William; Johnston, Keith P.

    2002-01-01

    A process is provided for catalyzing an organic reaction to form a reaction product by placing reactants and a catalyst for the organic reaction, the catalyst of a metal complex and at least one ligand soluble within one of the phases of said aqueous biphasic system, within an aqueous biphasic system including a water phase, a dense phase fluid, and a surfactant adapted for forming an emulsion or microemulsion within the aqueous biphasic system, the reactants soluble within one of the phases of the aqueous biphasic system and convertible in the presence of the catalyst to a product having low solubility in the phase in which the catalyst is soluble; and, maintaining the aqueous biphasic system under pressures, at temperatures, and for a period of time sufficient for the organic reaction to occur and form the reaction product and to maintain sufficient density on the dense phase fluid, the reaction product characterized as having low solubility in the phase in which the catalyst is soluble.

  9. Autologous osteochondral plug transplantation for osteochondrosis of the second metatarsal head: a case report

    Directory of Open Access Journals (Sweden)

    Kokubu Takeshi

    2011-07-01

    Full Text Available Abstract Introduction Osteochondrosis of the second or third metatarsal head is a rare condition called Freiberg's disease. To relieve foot pain, conservative treatment with a foot orthosis to reduce weight-bearing and immobilize the foot are recommended. In cases in which such treatments have proved to be ineffective, several surgical treatments have been performed. The appropriate surgical treatment for Freiberg's disease remains controversial. Case presentation We describe the case of a 20-year-old Japanese woman with a three-year history of right forefoot pain and no history of trauma. Two years after treatment by autologous osteochondral plug transplantation, she has neither complaints nor symptoms. Conclusion Autologous osteochondral plug transplantation represents a potentially successful surgical arthroplastic option in preserving the metatarsophalangeal joint in patients with Freiberg's disease.

  10. 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.

  11. Repair of large osteochondral defects with mix-mosaicplasty in a goat model.

    Science.gov (United States)

    Leng, Ping; Wang, Ying-Zhen; Zhang, Hai-Ning

    2013-03-01

    Osteochondral defects in weight-bearing regions must be repaired with cartilage and subchondral bone support simultaneously, as well as the integration between the 2, particularly in young, active patients. In this study, a new method called mix-mosaicplasty was used to reconstruct large osteochondral defects (6-mm diameter) in the weight-bearing region of the femoral condyle of goats. Two periosteum-bone plugs and 1 osteochondral plug harvested from the proximal tibia and intertrochlea groove were assembled to fill the defects in a mosaic mode. The goats were euthanized 16 weeks postoperatively, and the result of the repair process was assessed using macroscopy, morphologic analysis, electron microscope observation, glycosaminoglycan assay, and magnetic resonance imaging. Sixteen weeks postoperatively, the superficial surface of the defective region was covered with regenerated cartilage, and the periosteum-bone plugs were combined with each other. However, cleavage between cartilage plugs was noted. The donor site, which was filled with periosteum-bone plugs, was regenerated with fibrocartilage-like tissue. The repaired tissue was composed of small chondrocyte-like cells arranged tightly within an evenly distributed extracellular matrix containing type II collagen. Cells of the regenerated tissue in periosteum-bone plugs were smaller and distributed more densely. Electron microscopy demonstrated regular matrix fibers and abundant organelles within the repaired tissue. No significant differences of glycosaminoglycan content were observed between reconstructed tissue and normal hyaline cartilage. Magnetic resonance imaging revealed the healing process between plugs other than the control group. The new technique of mix-mosaicplasty can reconstruct full-thickness osteochondral compound defects in the weight-bearing region of the femoral condyle.

  12. 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...

  13. Intra-articular osteoid osteoma at the femoral trochlea treated with osteochondral autograft transplantation

    Science.gov (United States)

    Leeman, Joshua J; Motamedi, Daria; Wildman-Tobriner, Ben; O’Donnell, Richard J; Link, Thomas M

    2016-01-01

    We present the case of an intra-articular osteoid osteoma at the femoral trochlea. Intra-articular osteoid osteoma can present a diagnostic challenge both clinically and with imaging because it presents differently from the classic cortical osteoid osteoma. Given the lesion’s proximity to overlying cartilage, the patient underwent resection of the lesion with osteochondral autograft transplantation at the surgical defect. A comprehensive literature review and discussion of intra-articular osteoma will be provided. PMID:27761182

  14. Arthroscopic treatment for osteochondral lesions of the talus: analysis of outcome predictors

    Institute of Scientific and Technical Information of China (English)

    GUO Qin-wei; HU Yue-lin; JIAO Chen; YU Chang-long; AO Ying-fang

    2010-01-01

    Background Compared with traditional arthrotomy procedures, arthroscopic treatment for osteochondral lesions of the talus has some advantages. However, there has been considerable debate about the outcome predictors for this surgical technique. This study aimed to investigate the outcomes of arthroscopic treatment for osteochondral lesions of the talus, and analyze its outcome predictors.Methods Clinical data of 48 patients with osteochondral lesions of the talus who underwent ankle arthroscopy were studied. Arthroscopic debridement was performed on all patients, and microfracture was also performed in 36 cases. Scores on a subjective satisfaction questionnaire, visual analog scale (VAS) for pain, and the American Orthopedic Foot & Ankle Society (AOFAS) ankle and hindfoot scores were obtained before and after surgery.Results Five patients lost to follow up. The other forty-three patients, 8 of whom were athletes, were followed up for an average of 23.9 months. The average AOFAS post-operative score was 90.16±9.96, compared with 70.81±6.96 before surgery (t=9.353, P <0.001). The VAS pain score after the operation (2.51±9.45) was significantly lower than that before the operation (6.95±1.40) (t=8.647, P<0.001). Of the 43 patients, 35 (81.4%) had good or excellent results. There was no significant difference in outcome between the medial and lateral groups (z=0.205, P=0.838), while a better outcome was found with lesions smaller than 10 mm than those with larger lesions (z=2.199, P=0.028). Age, sex, athletic profession and location of the lesion did not significantly correlate with outcomes.Conclusions Arthroscopic treatment is effective and safe for osteochondral lesions of the talus. A strong correlation was found between the size of the lesion and successful outcome.

  15. Percutaneous CT-Guided Treatment of Osteochondritis Dissecans of the Sacroiliac Joint

    Energy Technology Data Exchange (ETDEWEB)

    Becce, Fabio, E-mail: fabio.becce@chuv.ch [University of Lausanne, Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois (Switzerland); Mouhsine, Elyazid [Clinique Hirslanden Bois-Cerf, Department of Orthopaedic Surgery (Switzerland); Mosimann, Pascal John; Anaye, Anass [University of Lausanne, Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois (Switzerland); Letovanec, Igor [University Institute of Pathology, Centre Hospitalier Universitaire Vaudois (Switzerland); Theumann, Nicolas [University of Lausanne, Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois (Switzerland)

    2012-08-15

    Osteochondritis dissecans (OCD) is a joint disorder that affects the articular cartilage and subchondral bone, most commonly at the knee. OCD of the sacroiliac joint is extremely rare. Management of OCD remains controversial, and surgery is often needed, especially when conservative treatment fails. We present a rare case of OCD involving the left sacroiliac joint successfully treated by percutaneous computed tomography-guided retrograde drilling and debridement.

  16. Progress on the biphase turbine at Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

    Cerini, D.; Hays, L.; Studhalter, W. [Douglas Energy Company, Placentia, CA (United States)

    1997-12-31

    The status of a Biphase turbine power plant being installed at the Cerro Prieto geothermal field is presented. The major modules for the power plant are completed except for a back pressure steam turbine. The power plant will be started in April 1997 with the Biphase turbine alone followed by the addition of the steam turbine module two months later. The current power plant performance level is 2780 kWe due to a decline in the well. An increase in power output to 4060 kWe by adding the flow from another well is planned. The addition of five Biphase power plants with a total power output of 21.2 megawatts is described.

  17. Spatial Engineering of Osteochondral Tissue Constructs Through Microfluidically Directed Differentiation of Mesenchymal Stem Cells.

    Science.gov (United States)

    Goldman, Stephen M; Barabino, Gilda A

    2016-01-01

    The development of tissue engineered osteochondral units has been slowed by a number of technical hurdles associated with recapitulating their heterogeneous nature ex vivo. Subsequently, numerous approaches with respect to cell sourcing, scaffolding composition, and culture media formulation have been pursued, which have led to high variability in outcomes and ultimately the lack of a consensus bioprocessing strategy. As such, the objective of this study was to standardize the design process by focusing on differentially supporting formation of cartilaginous and bony matrix by a single cell source in a spatially controlled manner within a single material system. A cell-polymer solution of bovine mesenchymal stem cells and agarose was cast against micromolds of a serpentine network and stacked to produce tissue constructs containing two independent microfluidic networks. Constructs were fluidically connected to two controlled flow loops and supplied with independently tuned differentiation parameters for chondrogenic and osteogenic induction, respectively. Constructs receiving inductive media showed differential gene expression of both chondrogenic and osteogenic markers in opposite directions along the thickness of the construct that was recapitulated at the protein level with respect to collagens I, II, and X. A control group receiving noninductive media showed homogeneous expression of these biomarkers measured in lower concentrations at both the mRNA and protein level. This work represents an important step in the rational design of engineered osteochondral units through establishment of an enabling technology for further optimization of scaffolding formulations and bioprocessing conditions toward the production of commercially viable osteochondral tissue products.

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

    Science.gov (United States)

    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.

  19. Biphasic Malignant Pleural Mesothelioma Masquerading as a Primary Skeletal Tumor

    Science.gov (United States)

    Diacovo, Maria Julia

    2016-01-01

    Biphasic malignant pleural mesothelioma is a rare malignant tumor, usually presenting as a pleural-based mass in a patient with history of chronic asbestos exposure. We herein report a case of a 41-year-old man who presented with chest pain and had a chest computed tomography (CT) scan suggestive of a primary skeletal tumor originating from the ribs (chondrosarcoma or osteosarcoma), with no history of asbestos exposure. CT-guided core needle biopsies were diagnosed as malignant sarcomatoid mesothelioma. Surgical resection and chest wall reconstruction were performed, confirming the diagnosis and revealing a secondary histologic component (epithelioid), supporting the diagnosis of biphasic malignant mesothelioma. PMID:27660729

  20. Biphasic Malignant Pleural Mesothelioma Masquerading as a Primary Skeletal Tumor

    Directory of Open Access Journals (Sweden)

    James Benjamin Gleason

    2016-01-01

    Full Text Available Biphasic malignant pleural mesothelioma is a rare malignant tumor, usually presenting as a pleural-based mass in a patient with history of chronic asbestos exposure. We herein report a case of a 41-year-old man who presented with chest pain and had a chest computed tomography (CT scan suggestive of a primary skeletal tumor originating from the ribs (chondrosarcoma or osteosarcoma, with no history of asbestos exposure. CT-guided core needle biopsies were diagnosed as malignant sarcomatoid mesothelioma. Surgical resection and chest wall reconstruction were performed, confirming the diagnosis and revealing a secondary histologic component (epithelioid, supporting the diagnosis of biphasic malignant mesothelioma.

  1. Fabrication and development of artificial osteochondral constructs based on cancellous bone/hydrogel hybrid scaffold.

    Science.gov (United States)

    Song, Kedong; Li, Liying; Yan, Xinyu; Zhang, Yu; Li, Ruipeng; Wang, Yiwei; Wang, Ling; Wang, Hong; Liu, Tianqing

    2016-06-01

    Using tissue engineering techniques, an artificial osteochondral construct was successfully fabricated to treat large osteochondral defects. In this study, porcine cancellous bones and chitosan/gelatin hydrogel scaffolds were used as substitutes to mimic bone and cartilage, respectively. The porosity and distribution of pore size in porcine bone was measured and the degradation ratio and swelling ratio for chitosan/gelatin hydrogel scaffolds was also determined in vitro. Surface morphology was analyzed with the scanning electron microscope (SEM). The physicochemical properties and the composition were tested by using an infrared instrument. A double layer composite scaffold was constructed via seeding adipose-derived stem cells (ADSCs) induced to chondrocytes and osteoblasts, followed by inoculation in cancellous bones and hydrogel scaffolds. Cell proliferation was assessed through Dead/Live staining and cellular activity was analyzed with IpWin5 software. Cell growth, adhesion and formation of extracellular matrix in composite scaffolds blank cancellous bones or hydrogel scaffolds were also analyzed. SEM analysis revealed a super porous internal structure of cancellous bone scaffolds and pore size was measured at an average of 410 ± 59 μm while porosity was recorded at 70.6 ± 1.7 %. In the hydrogel scaffold, the average pore size was measured at 117 ± 21 μm and the porosity and swelling rate were recorded at 83.4 ± 0.8 % and 362.0 ± 2.4 %, respectively. Furthermore, the remaining hydrogel weighed 80.76 ± 1.6 % of the original dry weight after hydration in PBS for 6 weeks. In summary, the cancellous bone and hydrogel composite scaffold is a promising biomaterial which shows an essential physical performance and strength with excellent osteochondral tissue interaction in situ. ADSCs are a suitable cell source for osteochondral composite reconstruction. Moreover, the bi-layered scaffold significantly enhanced cell proliferation compared to the cells seeded on

  2. 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

    Osteochondritis dissecans is a disorder in which fragments of articular cartilage and subchondral bone dislodge from the joint surface. We analyzed a five-generation family in which affected members had autosomal-dominant familial osteochondritis dissecans. A genome-wide linkage analysis identifi...

  3. Porous hydroxyapatite and biphasic calcium phosphate ceramics promote ectopic osteoblast differentiation from mesenchymal stem cells

    Science.gov (United States)

    Zhang, Lingli; Hanagata, Nobutaka; Maeda, Megumi; Minowa, Takashi; Ikoma, Toshiyuki; Fan, Hongsong; Zhang, Xingdong

    2009-04-01

    Because calcium phosphate (Ca-P) ceramics have been used as bone substitutes, it is necessary to investigate what effects the ceramics have on osteoblast maturation. We prepared three types of Ca-P ceramics with different Ca-P ratios, i.e. hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP), and biphasic calcium phosphate (BCP) ceramics with dense-smooth and porous structures. Comprehensive gene expression microarray analysis of mouse osteoblast-like cells cultured on these ceramics revealed that porous Ca-P ceramics considerably affected the gene expression profiles, having a higher potential for osteoblast maturation. In the in vivo study that followed, porous Ca-P ceramics were implanted into rat skeletal muscle. Sixteen weeks after the implantation, more alkaline-phosphatase-positive cells were observed in the pores of hydroxyapatite and BCP, and the expression of the osteocalcin gene (an osteoblast-specific marker) in tissue grown in pores was also higher in hydroxyapatite and BCP than in β-TCP. In the pores of any Ca-P ceramics, 16 weeks after the implantation, we detected the expressions of marker genes of the early differentiation stage of chondrocytes and the complete differentiation stage of adipocytes, which originate from mesenchymal stem cells, as well as osteoblasts. These marker gene expressions were not observed in the muscle tissue surrounding the implanted Ca-P ceramics. These observations indicate that porous hydroxyapatite and BCP had a greater potential for promoting the differentiation of mesenchymal stem cells into osteoblasts than β-TCP.

  4. Millicurrent stimulation of human articular chondrocytes cultivated in a collagen type-I gel and of human osteochondral explants

    Directory of Open Access Journals (Sweden)

    Silny Jiri

    2010-08-01

    Full Text Available Abstract Background Here we investigate the effect of millicurrent treatment on human chondrocytes cultivated in a collagen gel matrix and on human osteochondral explants. Methods Human chondrocytes from osteoarthritic knee joints were enzymatically released and transferred into a collagen type-I gel. Osteochondral explants and cell-seeded gel samples were cultivated in-vitro for three weeks. Samples of the verum groups were stimulated every two days by millicurrent treatment (3 mA, sinusoidal signal of 312 Hz amplitude modulated by two super-imposed signals of 0.28 Hz, while control samples remained unaffected. After recovery, collagen type-I, type-II, aggrecan, interleukin-1β, IL-6, TNFα and MMP13 were examined by immunohistochemistry and by real time PCR. Results With regard to the immunostainings 3 D gel samples and osteochondral explants did not show any differences between treatment and control group. The expression of all investigated genes of the 3 D gel samples was elevated following millicurrent treatment. While osteochondral explant gene expression of col-I, col-II and Il-1β was nearly unaffected, aggrecan gene expression was elevated. Following millicurrent treatment, IL-6, TNFα, and MMP13 gene expression decreased. In general, the standard deviations of the gene expression data were high, resulting in rarely significant results. Conclusions We conclude that millicurrent stimulation of human osteoarthritic chondrocytes cultivated in a 3 D collagen gel and of osteochondral explants directly influences cell metabolism.

  5. Dental Implants.

    Science.gov (United States)

    Griggs, Jason A

    2017-10-01

    Systematic reviews of literature over the period between 2008 and 2017 are discussed regarding clinical evidence for the factors affecting survival and failure of dental implants. The factors addressed include publication bias, tooth location, insertion torque, collar design, implant-abutment connection design, implant length, implant width, bone augmentation, platform switching, surface roughness, implant coatings, and the use of ceramic materials in the implant body and abutment. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Biphasic dose response in low level light therapy - an update.

    Science.gov (United States)

    Huang, Ying-Ying; Sharma, Sulbha K; Carroll, James; Hamblin, Michael R

    2011-01-01

    Low-level laser (light) therapy (LLLT) has been known since 1967 but still remains controversial due to incomplete understanding of the basic mechanisms and the selection of inappropriate dosimetric parameters that led to negative studies. The biphasic dose-response or Arndt-Schulz curve in LLLT has been shown both in vitro studies and in animal experiments. This review will provide an update to our previous (Huang et al. 2009) coverage of this topic. In vitro mediators of LLLT such as adenosine triphosphate (ATP) and mitochondrial membrane potential show biphasic patterns, while others such as mitochondrial reactive oxygen species show a triphasic dose-response with two distinct peaks. The Janus nature of reactive oxygen species (ROS) that may act as a beneficial signaling molecule at low concentrations and a harmful cytotoxic agent at high concentrations, may partly explain the observed responses in vivo. Transcranial LLLT for traumatic brain injury (TBI) in mice shows a distinct biphasic pattern with peaks in beneficial neurological effects observed when the number of treatments is varied, and when the energy density of an individual treatment is varied. Further understanding of the extent to which biphasic dose responses apply in LLLT will be necessary to optimize clinical treatments.

  7. Parallel-to-serial biphase-data converter

    Science.gov (United States)

    Truelove, R. D.

    1968-01-01

    Data converter produces a serial biphase output signal from parallel input data. Alternate bits are loaded into a shift register in complement form so that the bits appear at the end of the shift register in a true-complement form sequence.

  8. 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.

  9. Retrograde Percutaneous Drilling for Osteochondritis Dissecans of the Head of the Talus: Case Report and Review of the Literature.

    Science.gov (United States)

    Corominas, Laura; Sanpera, Ignacio; Masrouha, Karim; Sanpera-Iglesias, Julia

    2016-01-01

    Osteochondral lesions of the talus might be a more common cause of pain than previously recognized, especially among those involved in athletic activities. However, the location of an osteochondral lesion on the talar head is much less common than such lesions localized to the dome of the talus and can pose diagnostic difficulties. We present the case of a 14-year-old soccer player who complained of longstanding pain in his left foot. After unsuccessful conservative treatment consisting of rest and bracing, he was ultimately treated with retrograde percutaneous drilling of the talar head performed by a medial approach. This was followed by casting and non-weightbearing for 6 weeks, after which physical therapy was undertaken. He was able to return to full activity and remained asymptomatic during a 5-year observation period. Although rare, osteochondritis dissecans of the talar head should be considered in young athletes with persistent foot pain that is unresponsive to reasonable therapy.

  10. Autogenous osteochondral graft transplantation for steroid-induced osteonecrosis of the femoral condyle: A report of three young patients

    Directory of Open Access Journals (Sweden)

    Fujita Norifumi

    2012-04-01

    Full Text Available Abstract Steroid-induced osteonecrosis of the femoral condyle is a relatively uncommon condition and is often difficult to select appropriate treatment especially in young patients. Three young men (aged 25, 18, and 24 presented with severe pain and dysfunction of the knee diagnosed as steroid-induced osteonecrosis of the femoral condyle by magnetic resonance imaging (MRIs. Full-thickness cartilage defects sized 20 × 10, 15 × 10, and 30 × 20 mm respectively were classified as International Cartilage Repair Society Grade IV lesions and treated with osteochondral autograft transplantation. They were treated successfully with osteochondral autograft transplantation certificated by post-operative MRI and second look arthroscopy.

  11. Evaluation of the Early In Vivo Response of a Functionally Graded Macroporous Scaffold in an Osteochondral Defect in a Rabbit Model.

    Science.gov (United States)

    Barron, Valerie; Neary, Martin; Mohamed, Khalid Merghani Salid; Ansboro, Sharon; Shaw, Georgina; O'Malley, Grace; Rooney, Niall; Barry, Frank; Murphy, Mary

    2016-05-01

    Cartilage tissue engineering is a multifactorial problem requiring a wide range of material property requirements from provision of biological cues to facilitation of mechanical support in load-bearing diarthrodial joints. The study aim was to design, fabricate and characterize a template to promote endogenous cell recruitment for enhanced cartilage repair. A polylactic acid poly-ε-caprolactone (PLCL) support structure was fabricated using laser micromachining technology and thermal crimping to create a functionally-graded open pore network scaffold with a compressive modulus of 9.98 ± 1.41 MPa and a compressive stress at 50% strain of 8.59 ± 1.35 MPa. In parallel, rabbit mesenchymal stem cells were isolated and their growth characteristics, morphology and multipotency confirmed. Sterilization had no effect on construct chemical structure and cellular compatibility was confirmed. After four weeks implantation in an osteochondral defect in a rabbit model to assess biocompatibility, there was no evidence of inflammation or giant cells. Moreover, acellular constructs performed better than cell-seeded constructs with endogenous progenitor cells homing through microtunnels, differentiating to form neo-cartilage and strengthening integration with native tissue. These results suggest, albeit at an early stage of repair, that by modulating the architecture of a macroporous scaffold, pre-seeding with MSCs is not necessary for hyaline cartilage repair.

  12. Bilayered silk/silk-nanoCaP scaffolds for osteochondral tissue engineering: In vitro and in vivo assessment of biological performance.

    Science.gov (United States)

    Yan, Le-Ping; Silva-Correia, Joana; Oliveira, Mariana B; Vilela, Carlos; Pereira, Hélder; Sousa, Rui A; Mano, João F; Oliveira, Ana L; Oliveira, Joaquim M; Reis, Rui L

    2015-01-01

    Novel porous bilayered scaffolds, fully integrating a silk fibroin (SF) layer and a silk-nano calcium phosphate (silk-nanoCaP) layer for osteochondral defect (OCD) regeneration, were developed. Homogeneous porosity distribution was achieved in the scaffolds, with calcium phosphate phase only retained in the silk-nanoCaP layer. The scaffold presented compressive moduli of 0.4MPa in the wet state. Rabbit bone marrow mesenchymal stromal cells (RBMSCs) were cultured on the scaffolds, and good adhesion and proliferation were observed. The silk-nanoCaP layer showed a higher alkaline phosphatase level than the silk layer in osteogenic conditions. Subcutaneous implantation in rabbits demonstrated weak inflammation. In a rabbit knee critical size OCD model, the scaffolds firmly integrated into the host tissue. Histological and immunohistochemical analysis showed that collagen II positive cartilage and glycosaminoglycan regeneration presented in the silk layer, and de novo bone ingrowths and vessel formation were observed in the silk-nanoCaP layer. These bilayered scaffolds can therefore be promising candidates for OCD regeneration.

  13. Impact Insertion of Osteochondral Grafts: Interference Fit and Central Graft Reduction Affect Biomechanics and Cartilage Damage.

    Science.gov (United States)

    Su, Alvin W; Chen, Yunchan; Wailes, Dustin H; Wong, Van W; Cai, Shengqiang; Chen, Albert C; Bugbee, William D; Sah, Robert L

    2017-07-06

    An osteochondral graft (OCG) is an effective treatment for articular cartilage and osteochondral defects. Impact of an OCG during insertion into the osteochondral recipient site (OCR) can cause chondrocyte death and matrix damage. The aim of the present study was to analyze the effects of graft-host interference fit and a modified OCG geometry on OCG insertion biomechanics and cartilage damage. The effects of interference fit (radius of OCG - radius of OCR), loose (0.00mm), moderate (0.05mm), tight (0.10mm), and of a tight fit with OCG geometry modification (central region of decreased radius) were analyzed for OCG cylinders and OCR blocks from adult bovine knee joints with an instrumented drop tower apparatus. An increasingly tight OCG-OCR interference fit led to increased taps for insertion, peak axial force, graft cartilage axial compression, cumulative and total energy delivery to cartilage, lower time of peak axial force, lesser graft advancement during each tap, higher total crack length in the cartilage surface, and lower chondrocyte viability. The modified OCG, with reduction of diameter in the central area, altered the biomechanical insertion variables and biological consequences to be similar to those of the moderate interference fit scenario. Micro-computed tomography confirmed structural interference between the OCR bone and both the proximal and distal bone segments of the OCGs, with the central regions being slightly separated for the modified OCGs. These results clarify OCG insertion biomechanics and mechanobiology, and introduce a simple modification of OCGs that facilitates insertion with reduced energy while maintaining a structural interference fit. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  14. Cumulative Incidence of Osteochondritis Dissecans of the Capitellum in Child and Adolescent Baseball Players

    OpenAIRE

    Iwame, Toshiyuki; Matsuura, Tetsuya; Suzue, Naoto; Sairyo, Koichi

    2016-01-01

    Objectives: Prevalence of osteochondritis dissecans (OCD) of the capitellum is high among individuals who have played baseball since childhood. Recently two cross-sectional studies according to prevalence of OCD have been published. In a study of 1040 baseball players aged 10 to 12 years, Matsuura et al found that 2.1% of players had OCD, with no differences in prevalence according to age or player position. Kida et al., in their study of 2433 baseball players aged 12 to 18 years, found OCD i...

  15. 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.

  16. Review of biphasic insulin aspart in the treatment of type 1 and 2 diabetes

    Directory of Open Access Journals (Sweden)

    Nazia Raja-Khan

    2008-01-01

    Full Text Available Nazia Raja-Khan, Sarah S Warehime, Robert A GabbayDivision of Endocrinology, Diabetes, and Metabolism, Penn State Institute for Diabetes and Obesity, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USABackground: Insulin is an effective treatment for achieving glycemic control and preventing complications in patients with diabetes. In order to make insulin therapy more acceptable to patients, newer formulations of insulin have been developed, such as biphasic insulins. Biphasic insulins conveniently provide both prandial and basal insulin in a single injection. One of the most well-studied biphasic insulins is biphasic insulin aspart 70/30.Objective: Our goal was to review the current literature on the safety and efficacy of biphasic insulin aspart in type 1 and type 2 diabetes.Methods: A MEDLINE search was conducted using the terms “biphasic insulin aspart” to identify clinical studies and reviews.Results: Biphasic insulin aspart more effectively reduces post-prandial glucose compared to other biphasic insulins and basal insulins. Compared to biphasic insulin aspart, fasting glucose levels are lower with NPH, similar with glargine, and similar or lower with biphasic human insulin. Treat-to-target trials have shown that a goal HbA1c below 6.5 or 7% can be achieved with biphasic insulin aspart. The risk of hypoglycemia is similar to or less than that seen with other biphasic insulins or NPH insulin.Conclusion: Biphasic insulin aspart 70/30 is a safe and effective treatment option for patients with diabetes.Keywords: biphasic insulin aspart, insulin, diabetes

  17. Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems.

    Science.gov (United States)

    Passos, Helena; Luís, Andreia; Coutinho, João A P; Freire, Mara G

    2016-02-04

    The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process.

  18. Actinide recovery using aqueous biphasic extraction: Initial developmental studies

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, D.J.; Mensah-Biney, R.; Mertz, C.J.; Rollins, A.N.

    1992-08-01

    Aqueous biphasic extraction systems are being developed to treat radioactive wastes. The separation technique involves the selective partitioning of either solutes or colloid-size particles between two scible aqueous phases. Wet grinding of plutonium residues to an average particle size of one micron will be used to liberate the plutonium from the bulk of the particle matrix. The goal is to produce a plutonium concentrate that will integrate with existing and developing chemical recovery processes. Ideally, the process would produce a nonTRU waste stream. Coupling physical beneficiation with chemical processing will result in a substantial reduction in the volume of mixed wastes generated from dissolution recovery processes. As part of this program, we will also explore applications of aqueous biphasic extraction that include the separation and recovery of dissolved species such as metal ions and water-soluble organics. The expertise and data generated in this work will form the basis for developing more cost-effective processes for handling waste streams from environmental restoration and waste management activities within the DOE community. This report summarizes the experimental results obtained during the first year of this effort. Experimental efforts were focused on elucidating the surface and solution chemistry variables which govern partitioning behavior of plutonium and silica in aqueous biphasic extraction systems. Additional efforts were directed toward the development of wet grinding methods for producing ultrafine particles with diameters of one micron or less.

  19. 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

  20. 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.

  1. 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.

  2. A novel ultrasound technique for detection of osteochondral defects in the ankle joint: A parametric and feasibility study

    NARCIS (Netherlands)

    Sarkalkan, N.; Loeve, A.J.; Van Dongen, K.W.A.; Tuijthof, G.J.M.; Zadpoor, A.A.

    2015-01-01

    (Osteo)chondral defects (OCDs) in the ankle are currently diagnosed with modalities that are not convenient to use in long-term follow-ups. Ultrasound (US) imaging, which is a cost-effective and non-invasive alternative, has limited ability to discriminate OCDs. We aim to develop a new diagnostic te

  3. 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 hydrog

  4. Evaluation of Cartilage Repair by Mesenchymal Stem Cells Seeded on a PEOT/PBT Scaffold in an Osteochondral Defect

    NARCIS (Netherlands)

    Barron, V.; Merghani, K.; Shaw, G.; Coleman, C. M.; Hayes, J. S.; Ansboro, S.; Manian, A.; O’Malley, G.; Connolly, E.; Nandakumar, A.; van Blitterswijk, C. A.; Habibovic, P.; Moroni, L.; Shannon, F.; Murphy, J. M.; Barry, F.

    2015-01-01

    The main objective of this study was to evaluate the effectiveness of a mesenchymal stem cell (MSC)-seeded polyethylene-oxide-terephthalate/polybutylene-terephthalate (PEOT/PBT) scaffold for cartilage tissue repair in an osteochondral defect using a rabbit model. Material characterisation using scan

  5. 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 glyc

  6. 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.

    2008-01-01

    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 operat

  7. Transduction of anti-cell death protein FNK suppresses graft degeneration after autologous cylindrical osteochondral transplantation.

    Science.gov (United States)

    Nakachi, Noriki; Asoh, Sadamitsu; Watanabe, Nobuyoshi; Mori, Takashi; Matsushita, Takashi; Takai, Shinro; Ohta, Shigeo

    2009-03-01

    This study shows that artificial super antiapoptotic FNK protein fused with a protein transduction domain (PTD-FNK) maintains the quality of osteochondral transplant by preventing chondrocyte death. Cylindrical osteochondral grafts were obtained from enhanced green fluorescent protein (EGFP)-expressing transgenic rats, in which living chondrocytes express green fluorescence, and submerged into medium containing PTD-FNK, followed by transplantation into cartilage defects of wild-type rats by impact insertion simulating autologous transplantation. The tissues were histologically evaluated by hematoxylin-eosin and Safranin-O staining. At 1 week, chondrocyte alignment was normal in the PTD-FNK treatment group, whereas all grafts without PTD-FNK treatment showed mixed cluster cell distribution. At 4 weeks, all grafts with PTD-FNK treatment showed almost normal matrix, whereas two grafts without PTD-FNK treatment showed fibrocartilage. Notably, all grafts with PTD-FNK retained high intensity of Safranin-O staining, but all grafts without PTD-FNK largely lost Safranin-O staining. PTD-FNK significantly suppressed a decrease in the survival rate and the density of EGFP-positive cells at 1 and 2 weeks, and this tendency continued at 4 weeks. The results of terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP)-nick end-labeling staining showed that PTD-FNK inhibited cell death, indicating that PTD-FNK protects chondrocyte death and suppresses graft degeneration.

  8. Repair of articular cartilage in rabbit osteochondral defects promoted by extracorporeal shock wave therapy

    Science.gov (United States)

    Chu, C.-H.; Yen, Y.-S.; Chen, P.-L.; Wen, C.-Y.

    2015-03-01

    This study investigated the stimulative effect of extracorporeal shock wave therapy (ESWT) on the articular cartilage regeneration in the rabbit osteochondral defect model for the first time. An osteochondral defect, 3 mm in diameter and 3 mm in depth, was drilled in the patellar groove at the distal end of each femur in 24 mature New Zealand rabbits. The right patellar defects received 500 impulses of shock waves of (at 14 kV) at 1 week after surgery and were designated as the experimental samples; the left patellar defects served as control. At 4, 8, and 12 weeks after ESWT, cartilage repair was evaluated macroscopically and histologically using a semiquantitative grading scale. The total scores of the macroscopic evaluation at 4, 8, and 12 weeks in the experimental group were superior to those in the control group (statistical significance level ). As to the total scores of the histologic evaluation, the experimental group showed a tendency toward a better recovery than the control group at 4 weeks (). At 8 and 12 weeks the differences between the experimental and control groups became mild and had no significance on statistical analysis. These findings suggested that regeneration of articular cartilage defects might be promoted by ESWT, especially at the early stage. The easy and safe ESWT is potentially viable for clinical application.

  9. Juvenile osteochondritis dissecans: a 5-year review of the natural history using clinical and MRI evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Jacqueline A.; Cook, Jane V.; Warren, Mary E. [Radiology Department, Queen Mary' s Hospital for Children, Epsom and St Helier NHS Trust, Carshalton, Surrey SM5 1AA (United Kingdom); Churchill, Mark A. [Orthopaedic Department, Queen Mary' s Hospital for Children, Epsom and St Helier NHS Trust, Carshalton (United Kingdom)

    2003-06-01

    Although MRI prognostic features for juvenile osteochondritis dissecans (JOCD) have been determined, the natural history of JOCD on serial MRI has not been fully documented. To document the natural history of JOCD on serial MRI and to correlate this with arthroscopy and clinical outcome over a 5-year follow-up. Twenty-one knees in 19 patients (15 boys, 4 girls; age range 5-15 years) with JOCD underwent MRI and clinical follow-up over 5 years. Lesions were classified as stable or unstable on MRI and compared with clinical and arthroscopic data. On 5-year follow-up, 17 of 19 patients were asymptomatic and 2 of 19 had minimal pain. Fourteen arthroscopies were performed on 11/21 knees. One of twenty-one had fragment fixation. On initial MRI, eight knees had marked fragmentation, high signal at the fragment/bone interface and incomplete defects in the hyaline cartilage (MRI stage III-stable), but no tear. Of these, five had arthroscopy, all confirming intact cartilage. One of twenty-one knees was unstable (MRI stage IVb) with a detached osteochondral fragment, requiring surgery. Despite extensive subchondral bone changes on MRI, all cases with intact cartilage (95%) improved with conservative treatment. Early MRI allows prompt diagnosis and institution of conservative treatment. This results in healing and avoidance of surgery in most patients. (orig.)

  10. Imaging of acute injuries of the articular surfaces (chondral, osteochondral and subchondral fractures)

    Energy Technology Data Exchange (ETDEWEB)

    Bohndorf, K. [Department of Radiology, Zentralklinikum Augsburg (Germany)

    1999-10-01

    Fractures involving the articulating surfaces of bone are a common cause of chronic disability after joint injury. Acute fractures of the articular surface typically run parallel to the surface and are confined to the cartilage and/or the immediate subchondral cancellous bone. They should be distinguished from vertical or oblique bone fractures with intra-articular extension. This article reviews the mechanism of acute articular surface injuries, as well as their incidence, clinical presentation, radiologic appearance and treatment. A classification is presented based on direct inspection (arthroscopy) and imaging (especially MRI), emphasizing the distinction between lesions with intact (subchondral impaction and subchondral bone bruises) and disrupted (chondral, osteochondral lesions) cartilage. Hyaline cartilage, subchondral bone plate and subchondral cancellous bone are to be considered an anatomic unit. Subchondral articular surface lesions, osteochondral fractures and solely chondral fractures are different manifestations of impaction injuries that affect the articulating surface. Of the noninvasive imaging modalities, conventional radiography and MRI provide the most relevant information. The appropriate use of short tau inversion recovery, T1-weighted and T2-weighted (turbo) spin-echo as well as gradient-echo sequences, enables MRI to classify the various acute articular surface lesions with great accuracy and provides therapeutic guidance. (orig.)

  11. Image-Guided Techniques Improve the Short-Term Outcome of Autologous Osteochondral Cartilage Repair Surgeries

    Science.gov (United States)

    Devlin, Steven M.; Hurtig, Mark B.; Waldman, Stephen D.; Rudan, John F.; Bardana, Davide D.; Stewart, A. James

    2013-01-01

    Objective: Autologous osteochondral cartilage repair is a valuable reconstruction option for cartilage defects, but the accuracy to harvest and deliver osteochondral grafts remains problematic. We investigated whether image-guided methods (optically guided and template guided) can improve the outcome of these procedures. Design: Fifteen sheep were operated to create traumatic chondral injuries in each knee. After 4 months, the chondral defect in one knee was repaired using (a) conventional approach, (b) optically guided method, or (c) template-guided method. For both image-guided groups, harvest and delivery sites were preoperatively planned using custom-made software. During optically guided surgery, instrument position and orientation were tracked and superimposed onto the surgical plan. For the template-guided group, plastic templates were manufactured to allow an exact fit between template and the joint anatomy. Cylindrical holes within the template guided surgical tools according to the plan. Three months postsurgery, both knees were harvested and computed tomography scans were used to compare the reconstructed versus the native pre-injury joint surfaces. For each repaired defect, macroscopic (International Cartilage Repair Society [ICRS]) and histological repair (ICRS II) scores were assessed. Results: Three months after repair surgery, both image-guided surgical approaches resulted in significantly better histology scores compared with the conventional approach (improvement by 55%, P < 0.02). Interestingly, there were no significant differences found in cartilage surface reconstruction and macroscopic scores between the image-guided and the conventional surgeries. PMID:26069658

  12. Joint laminate degradation assessed by reflected ultrasound from the cartilage surface and osteochondral junction

    Energy Technology Data Exchange (ETDEWEB)

    Brown, C P; Crawford, R W; Oloyede, A [School of Engineering Systems, IHBI, QUT, Brisbane (Australia); Hughes, S W [School of Physical and Chemical Sciences, QUT, Brisbane (Australia)], E-mail: k.oloyede@qut.edu.au

    2008-08-07

    The ability to quantify and qualify the progression of joint degeneration is becoming increasingly important in surgery. This paper examines the patterns of relative ultrasound reflection from normal, artificially and naturally degraded cartilage-on-bone, particularly investigating the potential of the ratio of reflection coefficients from the surface and osteochondral junction in distinguishing normal from osteoarthritic tissue. To this end, the reflection coefficients from the articular surface and osteochondral junction of normal cartilage-on-bone samples were calculated and compared to samples after the removal of proteoglycans, disruption of the collagen meshwork, delipidization of the articular surface and mechanical abrasion. Our results show that the large variation across normal and degraded joint samples negates the use of an isolated bone reflection measurement and to a lesser extent, an isolated surface reflection. The relative surface to bone reflections, calculated as a ratio of reflection coefficients, provided a more consistent and statistically significant (p < 0.001) method for distinguishing each type of degradation, especially osteoarthritic degradation, and due to the complementary relationship between surface and bone reflections was found to be an effective method for distinguishing degraded from normal tissue in the osteoarthritic joint, independent of the site of initiation of the osteoarthritic process.

  13. Joint laminate degradation assessed by reflected ultrasound from the cartilage surface and osteochondral junction

    Science.gov (United States)

    Brown, C. P.; Hughes, S. W.; Crawford, R. W.; Oloyede, A.

    2008-08-01

    The ability to quantify and qualify the progression of joint degeneration is becoming increasingly important in surgery. This paper examines the patterns of relative ultrasound reflection from normal, artificially and naturally degraded cartilage-on-bone, particularly investigating the potential of the ratio of reflection coefficients from the surface and osteochondral junction in distinguishing normal from osteoarthritic tissue. To this end, the reflection coefficients from the articular surface and osteochondral junction of normal cartilage-on-bone samples were calculated and compared to samples after the removal of proteoglycans, disruption of the collagen meshwork, delipidization of the articular surface and mechanical abrasion. Our results show that the large variation across normal and degraded joint samples negates the use of an isolated bone reflection measurement and to a lesser extent, an isolated surface reflection. The relative surface to bone reflections, calculated as a ratio of reflection coefficients, provided a more consistent and statistically significant (p < 0.001) method for distinguishing each type of degradation, especially osteoarthritic degradation, and due to the complementary relationship between surface and bone reflections was found to be an effective method for distinguishing degraded from normal tissue in the osteoarthritic joint, independent of the site of initiation of the osteoarthritic process.

  14. Cochlear Implants

    Science.gov (United States)

    A cochlear implant is a small, complex electronic device that can help to provide a sense of sound. People who are ... of-hearing can get help from them. The implant consists of two parts. One part sits on ...

  15. Cochlear Implants

    Science.gov (United States)

    ... imaging (MRI) scans, to evaluate your inner ear anatomy. Cochlear implant surgery Cochlear implant surgery is usually performed as an outpatient procedure under general anesthesia. An incision is made behind the ear ...

  16. 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

  17. Investigation of structural resorption behavior of biphasic bioceramics with help of gravimetry, μCT, SEM, and XRD.

    Science.gov (United States)

    de Wild, Michael; Amacher, Fabienne; Bradbury, Christopher R; Molenberg, Aart

    2016-04-01

    Resorbable bone substitute materials are widely used for bone augmentation after tumor resection, parallel to implant placement, or in critical size bone defects. In this study, the structural dissolution of a biphasic calcium phosphate bone substitute material with a hydroxyapatite (HA)/tricalcium phosphate (β-TCP) ratio of 60/40 was investigated by repeatedly placing porous blocks in EDTA solution at 37 °C. At several time points, the blocks were investigated by SEM, µCT, and gravimetry. It was found that always complete 2-3 µm sized grains were removed from the structure and that the β-TCP is dissolved more rapidly. This selective dissolution of the β-TCP grains was confirmed by XRD measurements. The blocks were eroded from the outside toward the center. The structure remained mechanically stable because the central part showed a delayed degradation and because the slower dissolving HA grains preserved the integrity of the structure.

  18. Nanocrystalline biphasic resorbable calcium phosphate (HAp/β-TCP) thin film prepared by electron beam evaporation technique

    Energy Technology Data Exchange (ETDEWEB)

    Elayaraja, K.; Chandra, V. Sarath; Joshy, M.I. Ahymah; Suganthi, R.V. [Crystal Growth Centre, Anna University, Chennai 600025, Tamil Nadu (India); Asokan, K. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Kalkura, S. Narayana, E-mail: kalkura@yahoo.com [Crystal Growth Centre, Anna University, Chennai 600025, Tamil Nadu (India)

    2013-06-01

    Biphasic calcium phosphate (BCP) thin film having resorbable β-tricalcium phosphate (β-TCP) and non-resorbable hydroxyapatite (HAp) phases having enhanced bioactivity was synthesized by electron beam evaporation technique. Nanosized BCP was deposited as a layer (500 nm) on (0 0 1) silicon substrate by electron beam evaporation and crystalline phase of samples were found to improve on annealing at 700 °C. Uniform deposition of calcium phosphate on silicon substrate was verified from elemental mapping using scanning electron microscope (SEM-EDX). Annealing of the samples led to a decrease in surface roughness, hydrophobicity and dissolution of the coating layer. Amoxicillin loaded thin films exhibited significant bacterial resistance. In addition, BCP thin films did not exhibit any cytotoxicity. Antibiotics incorporated BCP coated implants might prevent the post-surgical infections and could promote bone-bonding of orthopedic devices.

  19. HAp granules encapsulated oxidized alginate-gelatin-biphasic calcium phosphate hydrogel for bone regeneration.

    Science.gov (United States)

    Sarker, Avik; Amirian, Jhaleh; Min, Young Ki; Lee, Byong Taek

    2015-11-01

    Bone repair in the critical size defect zone using 3D hydrogel scaffold is still a challenge in tissue engineering field. A novel type of hydrogel scaffold combining ceramic and polymer materials, therefore, was fabricated to meet this challenge. In this study, oxidized alginate-gelatin-biphasic calcium phosphate (OxAlg-Gel-BCP) and spherical hydroxyapatite (HAp) granules encapsulated OxAlg-Gel-BCP hydrogel complex were fabricated using freeze-drying method. Detailed morphological and material characterizations of OxAlg-Gel-BCP hydrogel (OGB00), 25wt% and 35wt% granules encapsulated hydrogel (OGB25 and OGB35) were carried out for micro-structure, porosity, chemical constituents, and compressive stress analysis. Cell viability, cell attachment, proliferation and differentiation behavior of rat bone marrow-derived stem cell (BMSC) on OGB00, OGB25 and OGB35 scaffolds were confirmed by MTT assay, Live-Dead assay, and confocal imaging in vitro experiments. Finally, OGB00 and OGB25 hydrogel scaffolds were implanted in the critical size defect of rabbit femoral chondyle for 4 and 8 weeks. The micro-CT analysis and histological studies conducted by H&E and Masson's trichrome demonstrated that a significantly higher (***phydrogel than in OxAlg-Gel-BCP complex alone. All results taken together, HAp granules encapsulated OxAlg-Gel-BCP system can be a promising 3D hydrogel scaffold for the healing of a critical bone defect.

  20. Biphasic Insulin Analogues in Type 2 Diabetes: Expert Panel Recommendations

    Directory of Open Access Journals (Sweden)

    Sema Akalın

    2011-09-01

    Full Text Available Recently, the prevalence of type 2 diabetes has reached pandemic levels all over the world, and the problem is still growing. Type 2 diabetes is a progressive disease, in which insulin resistance and decrease in beta cell function accompany obesity. Early disorder, which ensues in clinical progression of the disease, is the defect of early phase insulin secretion. Patients have already lost approximately half of their beta cell reserve at the time of diagnosis. Aims of type 2 diabetes treatment are to eliminate hyperglycemia caused by insufficient insulin secretion and/or insulin resistance, to slow down beta cell destruction/depletion, to improve concomitant metabolic problems and to prevent complications. In treatment algorithms, insulin is evaluated as a replacement therapy at the following stage after life style changes (medical nutrition therapy, exercise and oral anti-diabetic drugs (OADs options. Since beta cell depletion is present at initial stages of the disease, it transforms insulin therapy into an earlier approach in treatment stages. Premixed insulin forms are one of the proposed treatment options in patients with hyperglycemia that is not controlled by OADs. These types of insulins are developed to meet both basal and postprandial insulin requirements of patients. Currently, premixed human insulin forms are replaced by analogue insulin forms, which can mimic the physiological secretion in more acceptable manner. Biphasic analogue insulin is one of the readily available pre-mixed analogue insulin forms, an example of this, Biphasic Insulin aspart 30 which is the one of the premixed analoge insulin forms, contains 30% insulin aspart and 70% protaminated insulin aspart. Consensus recommending the individualized approach in insulin therapy implies that physicians should have more detailed information about the use of different insulin forms. Although a global consensus report about initiation, titration and intensification and the use

  1. The Streptococcus pneumoniae pilus-1 displays a biphasic expression pattern.

    Directory of Open Access Journals (Sweden)

    Gabriella De Angelis

    Full Text Available The Streptococcus pneumoniae pilus-1 is encoded by pilus islet 1 (PI-1, which has three clonal variants (clade I, II and III and is present in about 30% of clinical pneumococcal isolates. In vitro and in vivo assays have demonstrated that pilus-1 is involved in attachment to epithelial cells and virulence, as well as protection in mouse models of infection. Several reports suggest that pilus-1 expression is tightly regulated and involves the interplay of numerous genetic regulators, including the PI-1 positive regulator RlrA. In this report we provide evidence that pilus expression, when analyzed at the single-cell level in PI-1 positive strains, is biphasic. In fact, the strains present two phenotypically different sub-populations of bacteria, one that expresses the pilus, while the other does not. The proportions of these two phenotypes are variable among the strains tested and are not influenced by genotype, serotype, growth conditions, colony morphology or by the presence of antibodies directed toward the pilus components. Two sub-populations, enriched in pilus expressing or not expressing bacteria were obtained by means of colony selection and immuno-detection methods for five strains. PI-1 sequencing in the two sub-populations revealed the absence of mutations, thus indicating that the biphasic expression observed is not due to a genetic modification within PI-1. Microarray expression profile and western blot analyses on whole bacterial lysates performed comparing the two enriched sub-populations, revealed that pilus expression is regulated at the transcriptional level (on/off regulation, and that there are no other genes, in addition to those encoded by PI-1, concurrently regulated across the strains tested. Finally, we provide evidence that the over-expression of the RrlA positive regulator is sufficient to induce pilus expression in pilus-1 negative bacteria. Overall, the data presented here suggest that the observed biphasic pilus

  2. A new kinetic biphasic approach applied to biodiesel process intensification

    Energy Technology Data Exchange (ETDEWEB)

    Russo, V.; Tesser, R.; Di Serio, M.; Santacesaria, E. [Naples Univ. (Italy). Dept. of Chemistry

    2012-07-01

    Many different papers have been published on the kinetics of the transesterification of vegetable oil with methanol, in the presence of alkaline catalysts to produce biodiesel. All the proposed approaches are based on the assumption of a pseudo-monophasic system. The consequence of these approaches is that some experimental aspects cannot be described. For the reaction performed in batch conditions, for example, the monophasic approach is not able to reproduce the different plateau obtained by using different amount of catalyst or the induction time observed at low stirring rates. Moreover, it has been observed by operating in continuous reactors that micromixing has a dramatic effect on the reaction rate. At this purpose, we have recently observed that is possible to obtain a complete conversion to biodiesel in less than 10 seconds of reaction time. This observation is confirmed also by other authors using different types of reactors like: static mixers, micro-reactors, oscillatory flow reactors, cavitational reactors, microwave reactors or centrifugal contactors. In this work we will show that a recently proposed biphasic kinetic approach is able to describe all the aspects before mentioned that cannot be described by the monophasic kinetic model. In particular, we will show that the biphasic kinetic model can describe both the induction time observed in the batch reactors, at low stirring rate, and the very high conversions obtainable in a micro-channel reactor. The adopted biphasic kinetic model is based on a reliable reaction mechanism that will be validated by the experimental evidences reported in this work. (orig.)

  3. Dental Implant Surgery

    Science.gov (United States)

    ... here to find out more. Dental Implant Surgery Dental Implant Surgery Dental implant surgery is, of course, surgery, ... here to find out more. Dental Implant Surgery Dental Implant Surgery Dental implant surgery is, of course, surgery, ...

  4. Biphasic enantioselective olefin epoxidation using Tropos dibenzoazepinium catalysts.

    Science.gov (United States)

    Vachon, Jérôme; Pérollier, Céline; Monchaud, David; Marsol, Claire; Ditrich, Klaus; Lacour, Jérôme

    2005-07-22

    Several novel chiral iminium TRISPHAT [tris(tetrachlorobenzenediolato)phosphate(V)] salts combining a diphenylazepinium core, chiral exocyclic appendages, and lipophilic counterions have been prepared and tested in biphasic enantioselective olefin epoxidation conditions. Interestingly, the iminium salts derived from commercially available (S)- or (R)-1,2,2-trimethylpropylamine can display efficiency similar to those made from L-acetonamine. Variable-temperature NMR spectroscopy (VT-NMR) and circular dichroism (CD) experiments were performed in search of a correlation between good enantioselectivity in the products and high diastereomeric control of the biphenyl axial chirality of the catalysts.

  5. Gadopentetate-dimeglumine-enhanced MR imaging of osteonecrosis and osteochondritis dissecans of the elbow: initial experience.

    Science.gov (United States)

    Peiss, J; Adam, G; Casser, R; Urhahn, R; Günther, R W

    1995-01-01

    Magnetic resonance imaging (MRI) was performed on seven patients with aseptic osteonecrosis (n = 4) and osteochondritis dissecans (OCD; n = 3) of the elbow. Precontrast MRI was superior to plain radiographs, which did not show any abnormality in three cases of osteonecrosis. On gadopentetate-dimeglumine-enhanced T1-weighted images, which were obtained in three patients with osteonecrosis and three patients with OCD, all cases of osteonecrosis demonstrated homogeneous enhancement of the lesions. All cases of OCD were diagnosed on plain radiographs. On MRI one showed significant enhancement of the loose body. In another case an incompletely enhancing loose body was surrounded by a diffusely enhancing region. In the third patient only a small marginal enhancement of the defect was observed. Our results suggest that MRI can improve the accuracy in diagnosis of aseptic osteonecrosis of the elbow. The use of gadopentetate dimeglumine allows the viability of the lesions or the loose bodies to be demonstrated and reparative tissue to be detected.

  6. Feasibility of ultrasound imaging of osteochondral defects in the ankle: a clinical pilot study.

    Science.gov (United States)

    Kok, A C; Terra, M P; Muller, S; Askeland, C; van Dijk, C N; Kerkhoffs, G M M J; Tuijthof, G J M

    2014-10-01

    Talar osteochondral defects (OCDs) are imaged using magnetic resonance imaging (MRI) or computed tomography (CT). For extensive follow-up, ultrasound might be a fast, non-invasive alternative that images both bone and cartilage. In this study the potential of ultrasound, as compared with CT, in the imaging and grading of OCDs is explored. On the basis of prior CT scans, nine ankles of patients without OCDs and nine ankles of patients with anterocentral OCDs were selected and classified using the Loomer CT classification. A blinded expert skeletal radiologist imaged all ankles with ultrasound and recorded the presence of OCDs. Similarly to CT, ultrasound revealed typical morphologic OCD features, for example, cortex irregularities and loose fragments. Cartilage disruptions, Loomer grades IV (displaced fragment) and V (cyst with fibrous roof), were visible as well. This study encourages further research on the use of ultrasound as a follow-up imaging modality for OCDs located anteriorly or centrally on the talar dome.

  7. Bioglass®/chitosan-polycaprolactone bilayered composite scaffolds intended for osteochondral tissue engineering.

    Science.gov (United States)

    Yao, Qingqing; Nooeaid, Patcharakamon; Detsch, Rainer; Roether, Judith A; Dong, Yanming; Goudouri, Ourania-Menti; Schubert, Dirk W; Boccaccini, Aldo R

    2014-12-01

    Polymer-coated 45S5 Bioglass(®) (BG)/chitosan-polycaprolactone (BG/CS-PCL) bilayered composite scaffolds were prepared via foam replication and freeze-drying techniques for application in osteochondral tissue engineering. The CS-PCL coated and uncoated BG scaffolds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The mechanical properties of the coated scaffolds were significantly improved in comparison to uncoated scaffolds. The bioactivity and biodegradation behavior of scaffolds were studied in simulated body fluid (SBF) for up to 28 days. The interface between the BG scaffold and the polymer coating layer was observed by SEM and a suitable interpenetration of the polymer into the scaffold struts was found. The effects of coated and uncoated BG scaffolds on MG-63 osteoblast-like cells were evaluated by cell viability, adhesion and proliferation.

  8. 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.

  9. Cell-material interactions on biphasic polyurethane matrix.

    Science.gov (United States)

    Dicesare, Patrick; Fox, Wade M; Hill, Michael J; Krishnan, G Rajesh; Yang, Shuying; Sarkar, Debanjan

    2013-08-01

    Cell-matrix interaction is a key regulator for controlling stem cell fate in regenerative tissue engineering. These interactions are induced and controlled by the nanoscale features of extracellular matrix and are mimicked on synthetic matrices to control cell structure and functions. Recent studies have shown that nanostructured matrices can modulate stem cell behavior and exert specific role in tissue regeneration. In this study, we have demonstrated that nanostructured phase morphology of synthetic matrix can control adhesion, proliferation, organization and migration of human mesenchymal stem cells (MSCs). Nanostructured biodegradable polyurethanes (PU) with segmental composition exhibit biphasic morphology at nanoscale dimensions and can control cellular features of MSCs. Biodegradable PU with polyester soft segment and hard segment composed of aliphatic diisocyanates and dipeptide chain extender were designed to examine the effect polyurethane phase morphology. By altering the polyurethane composition, morphological architecture of PU was modulated and its effect was examined on MSC. Results show that MSCs can sense the nanoscale morphology of biphasic polyurethane matrix to exhibit distinct cellular features and, thus, signifies the relevance of matrix phase morphology. The role of nanostructured phases of a synthetic matrix in controlling cell-matrix interaction provides important insights for regulation of cell behavior on synthetic matrix and, therefore, is an important tool for engineering tissue regeneration. Copyright © 2012 Wiley Periodicals, Inc.

  10. Development and Characterization of Biphasic Hydroxyapatite/β-TCP Cements.

    Science.gov (United States)

    Gallinetti, Sara; Canal, Cristina; Ginebra, Maria-Pau; Ferreira, J

    2014-04-01

    Biphasic calcium phosphate bioceramics composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have relevant properties as synthetic bone grafts, such as tunable resorption, bioactivity, and intrinsic osteoinduction. However, they have some limitations associated to their condition of high-temperature ceramics. In this work self-setting Biphasic Calcium Phosphate Cements (BCPCs) with different HA/β-TCP ratios were obtained from self-setting α-TCP/β-TCP pastes. The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area. Due to its higher solubility, α-TCP was fully hydrolyzed to a calcium-deficient HA (CDHA), whereas β-TCP remained unreacted and completely embedded in the CDHA matrix. Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements. Ca(2+) release and degradation in acidic medium was similar in all the BCPCs within the timeframe studied, although differences might be expected in longer term studies once β-TCP, the more soluble phase was exposed to the surrounding media.

  11. Cell–material interactions on biphasic polyurethane matrix

    Science.gov (United States)

    Dicesare, Patrick; Fox, Wade M.; Hill, Michael J.; Krishnan, G. Rajesh; Yang, Shuying; Sarkar, Debanjan

    2013-01-01

    Cell–matrix interaction is a key regulator for controlling stem cell fate in regenerative tissue engineering. These interactions are induced and controlled by the nanoscale features of extracellular matrix and are mimicked on synthetic matrices to control cell structure and functions. Recent studies have shown that nanostructured matrices can modulate stem cell behavior and exert specific role in tissue regeneration. In this study, we have demonstrated that nanostructured phase morphology of synthetic matrix can control adhesion, proliferation, organization and migration of human mesenchymal stem cells (MSCs). Nanostructured biodegradable polyurethanes (PU) with segmental composition exhibit biphasic morphology at nanoscale dimensions and can control cellular features of MSCs. Biodegradable PU with polyester soft segment and hard segment composed of aliphatic diisocyanates and dipeptide chain extender were designed to examine the effect polyurethane phase morphology. By altering the polyurethane composition, morphological architecture of PU was modulated and its effect was examined on MSC. Results show that MSCs can sense the nanoscale morphology of biphasic polyurethane matrix to exhibit distinct cellular features and, thus, signifies the relevance of matrix phase morphology. The role of nanostructured phases of a synthetic matrix in controlling cell–matrix interaction provides important insights for regulation of cell behavior on synthetic matrix and, therefore, is an important tool for engineering tissue regeneration. PMID:23255285

  12. Biphasic Chromatin Structure and FISH Signals Reflect Intranuclear Order

    Directory of Open Access Journals (Sweden)

    Jyoti P. Chaudhuri

    2005-01-01

    Full Text Available Background and Aim: One of the two parental allelic genes may selectively be expressed, regulated by imprinting, X-inactivation or by other less known mechanisms. This study aims to reflect on such genetic mechanisms. Materials and Methods: Slides from short term cultures or direct smears of blood, bone marrow and amniotic fluids were hybridized with FISH probes singly, combined or sequentially. Two to three hundred cells were examined from each preparation. Results and Aignificance: A small number of cells (up to about 5%, more frequent in leukemia cases, showed the twin features: (1 nuclei with biphasic chromatin, one part decondensed and the other condensed; and (2 homologous FISH signals distributed equitably in those two regions. The biphasic chromatin structure with equitable distribution of the homologous FISH signals may correspond to the two sets of chromosomes, supporting observations on ploidywise intranuclear order. The decondensed chromatin may relate to enhanced transcriptions or advanced replications. Conclusions: Transcriptions of only one of the two parental genomes cause allelic exclusion. Genomes may switch with alternating monoallelic expression of biallelic genes as an efficient genetic mechanism. If genomes fail to switch, allelic exclusion may lead to malignancy. Similarly, a genome-wide monoallelic replication may tilt the balance of heterozygosity resulting in aneusomy, initiating early events in malignant transformation and in predicting cancer mortality.

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

    Directory of Open Access Journals (Sweden)

    KM Elson

    2015-06-01

    Full Text Available 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.

  14. Return to Sport After Operative Management of Osteochondritis Dissecans of the Capitellum

    Science.gov (United States)

    Westermann, Robert W.; Hancock, Kyle J.; Buckwalter, Joseph A.; Kopp, Benjamin; Glass, Natalie; Wolf, Brian R.

    2016-01-01

    Background: Capitellar osteochondritis dissecans (OCD) is commonly managed surgically in symptomatic adolesent throwers and gymnasts. Little is known about the impact that surgical technique has on return to sport. Purpose: To evaluate the clinical outcomes and return-to-sport rates after operative management of OCD lesions in adolescent athletes. Study Design: Systematic review; Level of evidence, 4. Methods: The PubMed, CINAHL, EMBASE, SPORTDiscus (EBSCO), and Cochrane Central Register of Controlled Trials databases were queried for studies evaluating outcomes and return to sport after surgical management of OCD of the capitellum. Two independent reviewers conducted a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies reporting patient outcomes with return-to-sport data and minimum 6-month follow-up were included in the review. Results: After review, 24 studies reporting outcomes in 492 patients (mean age ± SD, 14.3 ± 0.9 years) were analyzed. The overall return-to-sport rate was 86% at a mean 5.6 months. Return to the highest preoperative level of sport was most common after osteochondral autograft procedures (94%) compared with debridement and marrow stimulation procedures (71%) or OCD fixation surgery (64%). Elbow range of motion improved by 15.9° after surgery. The Timmerman-Andrews subjective and objective scores significantly improved after surgery. Complications were low (<5%), with 2 cases of donor site morbidity after osteoarticular autograft transfer (OAT) autograft harvest. The most common indications for reoperation were repeat debridement/loose body removal. Conclusion: A high rate of return to sport was observed after operative management of capitellar OCD. Patients were more likely to return to their highest level of preoperative sport after OAT autograft compared with debridement or fixation. Significant improvements in elbow range of motion and patient outcomes are

  15. Clinical outcome of internal fixation of unstable juvenile osteochondritis dissecans lesions of the knee.

    Science.gov (United States)

    Webb, Jonathan E; Lewallen, Laura W; Christophersen, Christy; Krych, Aaron J; McIntosh, Amy L

    2013-11-01

    Juvenile osteochondritis dissecans (OCD) lesions of the knee are a common cause of knee pain in skeletally immature patients.The authors sought to determine lesion healing rates, the risk factors associated with failure to heal, and the clinical outcomes for patients who underwent internal fixation for unstable OCD lesions. A retrospective review was conducted of all patients who underwent internal fixation of OCD lesions from 1999 to 2009. Using validated scoring systems, clinical outcome and functional activity were evaluated at the follow-up. The study group comprised 19 patients (20 knees). Mean patient age was 14.5 years (range, 12-17 years). Mean clinical follow-up was 7 years (range, 2-13 years). Mean radiographic follow-up was 2.5 years (range, 0.5-9 years). Fourteen (70%) lesions were grade 3 and 6 (30%) were grade 4. Eleven knees had lateral condyle lesions and 9 had medial lesions. Bioabsorbable fixation was used in 13 knees, metal fixation was used in 5 knees, and 2 knees were fixed with a combination of methods. Osseous integration was evident in 15 (75%) of 20 knees at final follow-up. The 5 unhealed lesions were lateral condylar lesions. Mean Tegner activity scores improved from 3.3 preoperatively to 5.6 at final follow-up. Mean Lysholm and International Knee Documentation Committee scores were 86.8 and 88.7, respectively, at final follow-up. Further operative intervention was required in 11 knees, with 50% of patients undergoing removal of hardware and 15% requiring subsequent osteochondral allograft transplantation. The authors recommend bioabsorbable fixation for symptomatic stable lesions and metal compression screws with staged removal for unstable lesions.

  16. RNA-seq Analysis of Clinical-Grade Osteochondral Allografts Reveals Activation of Early Response Genes

    Science.gov (United States)

    Lin, Yang; Lewallen, Eric A.; Camilleri, Emily T.; Bonin, Carolina A.; Jones, Dakota L.; Dudakovic, Amel; Galeano-Garces, Catalina; Wang, Wei; Karperien, Marcel J.; Larson, Annalise N.; Dahm, Diane L.; Stuart, Michael J.; Levy, Bruce A.; Smith, Jay; Ryssman, Daniel B.; Westendorf, Jennifer J.; Im, Hee-Jeong; van Wijnen, Andre J.; Riester, Scott M.; Krych, Aaron J.

    2016-01-01

    Preservation of osteochondral allografts used for transplantation is critical to ensure favorable outcomes for patients after surgical treatment of cartilage defects. To study the biological effects of protocols currently used for cartilage storage, we investigated differences in gene expression between stored allograft cartilage and fresh cartilage from living donors using high throughput molecular screening strategies. We applied next generation RNA sequencing (RNA-seq) and real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) to assess genome-wide differences in mRNA expression between stored allograft cartilage and fresh cartilage tissue from living donors. Gene ontology analysis was used to characterize biological pathways associated with differentially expressed genes. Our studies establish reduced levels of mRNAs encoding cartilage related extracellular matrix (ECM) proteins (i.e., COL1A1, COL2A1, COL10A1, ACAN, DCN, HAPLN1, TNC, and COMP) in stored cartilage. These changes occur concomitantly with increased expression of “early response genes” that encode transcription factors mediating stress/cytoprotective responses (i.e., EGR1, EGR2, EGR3, MYC, FOS, FOSB, FOSL1, FOSL2, JUN, JUNB, and JUND). The elevated expression of “early response genes” and reduced levels of ECM-related mRNAs in stored cartilage allografts suggests that tissue viability may be maintained by a cytoprotective program that reduces cell metabolic activity. These findings have potential implications for future studies focused on quality assessment and clinical optimization of osteochondral allografts used for cartilage transplantation. PMID:26909883

  17. Implantable Microimagers

    Directory of Open Access Journals (Sweden)

    Jun Ohta

    2008-05-01

    Full Text Available Implantable devices such as cardiac pacemakers, drug-delivery systems, and defibrillators have had a tremendous impact on the quality of live for many disabled people. To date, many devices have been developed for implantation into various parts of the human body. In this paper, we focus on devices implanted in the head. In particular, we describe the technologies necessary to create implantable microimagers. Design, fabrication, and implementation issues are discussed vis-à-vis two examples of implantable microimagers; the retinal prosthesis and in vivo neuro-microimager. Testing of these devices in animals verify the use of the microimagers in the implanted state. We believe that further advancement of these devices will lead to the development of a new method for medical and scientific applications.

  18. Osteochondral Fracture Lateral Femoral Condyle Treated with ORIF Using Z-Plasty: A Modification of Coonse and Adams Approach

    Directory of Open Access Journals (Sweden)

    Sanjay Agarwala

    2011-01-01

    Full Text Available Osteochondral fractures of lateral femoral condyle are common in adolescents and young adults. They are usually caused by direct trauma or twisting injuries of the knee. We present a case of large osteochondral fracture of lateral femoral condyle involving the articular surface in a fifteen-year-old male with a positive history of significant weight gain of 5 kilograms in last six months. Blood investigations reported low vitamin D and testosterone levels with elevated alkaline phosphatase. Adequate exposure was achieved by doing Z-plasty of quadriceps apparatus. The fracture was treated with open reduction and internal fixation using Herbert's screws. Medical management in the form of vitamin D and calcium along with testosterone was given. After the surgery, full weight-bearing was allowed at three months. At one year followup, patient has good quadriceps function without any weakness of the muscle.

  19. Costo-osteochondral graft for post-traumatic osteonecrosis of the radial head in an adolescent boy.

    Science.gov (United States)

    Iwai, S; Sato, K; Nakamura, T; Okazaki, M; Itoh, Y; Toyama, Y; Ikegami, H

    2011-01-01

    We present a case of post-traumatic osteonecrosis of the radial head in a 13-year-old boy which was treated with costo-osteochondral grafts. A satisfactory outcome was seen at a follow-up of two years and ten months. Although costo-osteochondral grafting has been used in the treatment of defects in articular cartilage, especially in the hand and the elbow, the extension of the technique to manage post-traumatic osteonecrosis of the radial head in a child has not previously been reported in the English language literature. Complete relief of pain was obtained and an improvement in the range of movement was observed. The long-term results remain uncertain.

  20. Evaluation of Biphasic Culture System for Mycobacterial Isolation from the Sputum of Patients with Pulmonary Tuberculosis

    Directory of Open Access Journals (Sweden)

    Ghatole M

    2005-01-01

    Full Text Available Mycobacterial diseases continue to cause high morbidity and mortality. Isolation, identification and sensitivity testing form the backbone of laboratory investigations. M. tuberculosis isolation needs 6-8 weeks on conventional egg containing media. For rapid isolation various methods have been evaluated. We evaluated biphasic system (Middlebrook 7H11 agar slant + Middlebrook 9H broth in comparison with Lowenstein - Jensen (LJ medium. In smear positive cases biphasic system showed the recovery rate of 97.05% as against 79.41% on LJ on incubation for 21± 4.44 and 28±3.76 days respectively. In smear negative and culture positive cases biphasic system and LJ showed isolation rates of 91.66% and 66.6% after 36±3.44 and 41± 4.09 days respectively. Biphasic system showed lower contamination rate (1.33%. Biphasic medium is superior to LJ medium in isolation of M. tuberculosis .

  1. Immunologic testing of xeno-derived osteochondral grafts using peripheral blood mononuclear cells from healthy human donors

    Directory of Open Access Journals (Sweden)

    Targoni Oleg S

    2005-06-01

    Full Text Available Abstract Background One means of treating osteoarthritis is with autologous or allogeneic osteochondral grafts. The purpose of this study was to evaluate the innate immunological response in humans toward xeno-derived osteochondral grafts that have been partially or entirely treated by the photooxidation process. Methods The antigens tested included bovine, porcine, ovine and equine osteochondral samples that have been treated in successive steps of photooxidation. ELISPOT assays were used to evaluate the production of IL-1, IL-4, IL-6, IL-10, IL-12 and TNF-α by human monocytes in response to the antigens. Results Results indicated vigorous production of IL-1, IL-6, IL-10 and TNF-α in response to untreated bovine, porcine and equine specimens. This indicates that these samples are perceived as foreign, or stimulatory, by the human monocytes. There was no induction of IL-4 or IL-12, which is required for Th2 and Th1 immunity, respectively. In contrast, the processed bovine, porcine and equine samples did not induce significant activation of cells of the innate immune system. This occurred after the first step in processing (after cleaning in increasing strengths of ethanol. This suggests that the processing steps dramatically, if not completely, negated the immunostimulatory properties of the test sample. The results for the ovine samples indicate a reverse response. Conclusion The findings of the study suggest that photooxidized bovine, porcine or equine samples have the potential to be used as an osteochondral graft. Although the first step in processing reduced the immunological response, photooxidation is still necessary to retain the structure and mechanical integrity of the cartilage, which would allow for immediate joint resurfacing.

  2. Does extracorporeal shock wave therapy enhance healing of osteochondritis dissecans of the rabbit knee?: a pilot study.

    Science.gov (United States)

    Lyon, Roger; Liu, Xue Cheng; Kubin, Martin; Schwab, Joseph

    2013-04-01

    Severe osteochondritis dissecans (OCD) in children and adolescents often necessitates surgical interventions (ie, drilling, excision, or débridement). Since extracorporeal shock wave therapy (ESWT) enhances healing of long-bone nonunion fractures, we speculated ESWT would reactivate the healing process in OCD lesions. We asked whether ESWT would enhance articular cartilage quality, bone and cartilage density, and histopathology of osteochondral lesions compared to nontreated controls in an OCD rabbit model. We harvested a 4-mm-diameter plug of the weightbearing osteochondral surface on the medial femoral condyle of each knee in 20 skeletally immature (8-week-old) female rabbits. We placed a piece of acellular collagen-glycosaminoglycan matrix into the cavity and then replaced the plug. Two weeks after surgery, we sedated each rabbit and treated the right knee in a single setting with shock waves: 4000 impulses at 4 Hz and 18 kV. The left knee was a sham control. Ten weeks after surgery, we assessed cartilage morphology of the lesion using a modified Outerbridge Grading System, bone and cartilage density using histologic imaging, bone and cartilage morphology using the histopathology assessment system, and radiographic bone density and union and compared these parameters between ESWT-treated and control knees. Histologically, we observed more mature bone formation and better healing (1.1 versus 3.4) and density of the cartilage (60 versus 49) on the treated side. Radiographically, we noted an increase in bony density (154 versus 138) after ESWT. ESWT accelerated the healing rate and improved cartilage and subchondral bone quality in the OCD rabbit model. This therapeutic modality may be applicable in OCD treatment in the pediatric population. Future research will be necessary to determine whether it may play a role in healing of human osteochondral defects.

  3. Predictors of biphasic reactions in the emergency department for patients with anaphylaxis.

    Science.gov (United States)

    Lee, Sangil; Bellolio, M Fernanda; Hess, Erik P; Campbell, Ronna L

    2014-01-01

    A biphasic reaction is the recurrence of anaphylaxis symptoms within 72 hours of the initial anaphylactic event, without re-exposure to the trigger. Biphasic reactions are uncommon and unpredictable, and risk factors for biphasic reactions are poorly understood. To identify predictors of biphasic anaphylactic reactions in patients with anaphylaxis in the emergency department (ED). Patients of all ages who presented to the ED and met diagnostic criteria for anaphylaxis from April 2008 to January 2013 at an academic medical center with 73,000 annual patient visits were consecutively included. We collected data on patient characteristics, suspected triggers, signs and symptoms, ED management, and disposition. Univariate analyses were performed to estimate the association between potential predictor variables and biphasic reactions. We report associations as odds ratios (OR) and corresponding 95% CIs. Among 541 patients with anaphylaxis, median age was 34.6 years (interquartile range, 18-52 years), and 320 (59%) were female patients. Twenty-one patients (4%) had biphasic reactions. Two pediatric patients, ages of 5 years old and 16 years old, developed a biphasic reaction. The median time between the resolution of initial symptoms and onset of the biphasic reaction was 7 hours (range, 1-72 hours). Biphasic reactions were associated with a history of prior anaphylaxis (OR 2.6 [95% CI, 1.1-6.4]; P = .029), unknown precipitant (OR 2.6 [95% CI, 1.1-6.2]; P = .03), symptoms of diarrhea (OR 4.5 [95% CI, 1.4-14.0]; P = .024), and wheezing (OR 2.6 [95% CI, 1.4-8.9]; P = .029). Patients with a history of prior anaphylaxis, an unknown precipitant, or who present with symptoms of diarrhea or wheezing may be at increased risk for a biphasic reaction. Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  4. Influence of surface microstructure and chemistry on osteoinduction and osteoclastogenesis by biphasic calcium phosphate discs

    Directory of Open Access Journals (Sweden)

    NL Davison

    2015-06-01

    Full Text Available It has been reported that surface microstructural dimensions can influence the osteoinductivity of calcium phosphates (CaPs, and osteoclasts may play a role in this process. We hypothesised that surface structural dimensions of ≤ 1 μm trigger osteoinduction and osteoclast formation irrespective of macrostructure (e.g., concavities, interconnected macropores, interparticle space or surface chemistry. To test this, planar discs made of biphasic calcium phosphate (BCP: 80 % hydroxyapatite, 20 % tricalcium phosphate were prepared with different surface structural dimensions – either ~ 1 μm (BCP1150 or ~ 2-4 μm (BCP1300 – and no macropores or concavities. A third material was made by sputter coating BCP1150 with titanium (BCP1150Ti, thereby changing its surface chemistry but preserving its surface structure and chemical reactivity. After intramuscular implantation in 5 dogs for 12 weeks, BCP1150 formed ectopic bone in 4 out of 5 samples, BCP1150Ti formed ectopic bone in 3 out of 5 samples, and BCP1300 formed no ectopic bone in any of the 5 samples. In vivo, large multinucleated osteoclast-like cells densely colonised BCP1150, smaller osteoclast-like cells formed on BCP1150Ti, and osteoclast-like cells scarcely formed on BCP1300. In vitro, RAW264.7 cells cultured on the surface of BCP1150 and BCP1150Ti in the presence of osteoclast differentiation factor RANKL (receptor activator for NF-κB ligand proliferated then differentiated into multinucleated osteoclast-like cells with positive tartrate resistant acid phosphatase (TRAP activity. However, cell proliferation, fusion, and TRAP activity were all significantly inhibited on BCP1300. These results indicate that of the material parameters tested – namely, surface microstructure, macrostructure, and surface chemistry – microstructural dimensions are critical in promoting osteoclastogenesis and triggering ectopic bone formation.

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

    Directory of Open Access Journals (Sweden)

    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

  6. Persistent bone marrow edema after osteochondral autograft transplantation in the knee joint

    Energy Technology Data Exchange (ETDEWEB)

    Nemec, Stefan Franz [MR Centre of Excellence, Department of Radiology, Medical University Vienna, Lazarettgasse 14, 1090 Vienna (Austria)], E-mail: stefan.nemec@meduniwien.ac.at; Marlovits, Stefan [Department of Traumatology, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna (Austria); Trattnig, Siegfried [MR Centre of Excellence, Department of Radiology, Medical University Vienna, Lazarettgasse 14, 1090 Vienna (Austria)

    2009-07-15

    Background and objective: The assessment of bone marrow edema-like signal intensity in magnetic resonance imaging (MRI) in patients after osteochondral autograft transplantation (OCT) in the knee joint is a parameter of yet indefinite value. This study determines the prevalence of persistent edema-like signal intensity in OCT patients and evaluates the correlation between edema and morphological imaging findings of the graft and clinical pain symptoms. Materials and methods: In this longitudinal observational study, 10 patients after OCT were followed by MRI prospectively 1 month, 3 months, 6 months, 12 months, and 24 months post-operatively. All MR examinations were performed on a 1.0 T MR unit with the same protocol using a modified scoring system (magnetic resonance observation of cartilage repair tissue-MOCART) for evaluation. Edema-like signal intensity in and beneath the osteochondral graft was assessed in its prevalence and graded using a coronal short tau inversion recovery fast spin echo (STIR-FSE) sequence: grade 1, normal; grade 2, moderate (diameter <2 cm); grade 3, severe (diameter >2 cm). The finding of edema-like signal intensity was correlated with graded parameters describing the morphology of the repair tissue assessed in a sagittal dual FSE sequence including: (a) surface of repair tissue: grade 1, intact; grade 2, damaged. (b) Cartilage interface: grade 1, complete; grade 2, incomplete. (c) Bone interface: grade 1, complete; grade 2, delamination. The finding of edema-like signal intensity was also correlated with the KOOS pain score assessing knee pain after 12 months. Results: Initially, after 1 month the prevalence of edema-like signal intensity was 70% (7/10 patients) and finally after 24 months 60% (6/10 patients). We found no significant relationship between the prevalence and degree of edema-like signal intensity and parameters describing the morphology of the repair tissue. Also the clinical pain score did not show significant

  7. Peripheral Blood Mononuclear Cells Enhance Cartilage Repair in in vivo Osteochondral Defect Model.

    Directory of Open Access Journals (Sweden)

    Niina Hopper

    Full Text Available This study characterized peripheral blood mononuclear cells (PBMC in terms of their potential in cartilage repair and investigated their ability to improve the healing in a pre-clinical large animal model. Human PBMCs were isolated with gradient centrifugation and adherent PBMC's were evaluated for their ability to differentiate into adipogenic, chondrogenic and osteogenic lineages and also for their expression of musculoskeletal genes. The phenotype of the PBMCs was evaluated using Stro-1, CD34, CD44, CD45, CD90, CD106, CD105, CD146 and CD166 cell surface markers. Osteochondral defects were created in the medial femoral condyle (MFC of 24 Welsh mountain sheep and evaluated at a six month time point. Four cell treatment groups were evaluated in combination with collagen-GAG-scaffold: (1 MSC alone; (2 MSCs and PBMCs at a ratio of 20:1; (3 MSCs and PBMC at a ratio of 2:1 and (4 PBMCs alone. Samples from the surgical site were evaluated for mechanical properties, ICRS score and histological repair. Fresh PBMC samples were 90% positive for hematopoietic cell surface markers and negative for the MSC antibody panel (<1%, p = 0.006. However, the adherent PBMC population expressed mesenchymal stem cell markers in hypoxic culture and lacked CD34/45 positive cells (<0.2%. This finding demonstrated that the adherent cells had acquired an MSC-like phenotype and transformed in hypoxia from their original hematopoietic lineage. Four key genes in muskuloskeletal biology were significantly upregulated in adherent PBMCs by hypoxia: BMP2 4.2-fold (p = 0.0007, BMP6 10.7-fold (p = 0.0004, GDF5 2.0-fold (p = 0.002 and COL1 5.0-fold (p = 0.046. The monolayer multilineage analysis confirmed the trilineage mesenchymal potential of the adherent PBMCs. PBMC cell therapy was equally good as bone marrow MSC therapy for defects in the ovine large animal model. Our results show that PBMCs support cartilage healing and oxygen tension of the environment was found to have a key

  8. Goserelin Implant

    Science.gov (United States)

    ... in men (blockage that causes difficulty urinating), or heart or liver disease.tell your doctor if you are pregnant or plan to become pregnant. Goserelin implant should not be used in pregnant women, except ...

  9. Contraceptive implants.

    Science.gov (United States)

    McDonald-Mosley, Raegan; Burke, Anne E

    2010-03-01

    Implantable contraception has been extensively used worldwide. Implants are one of the most effective and reversible methods of contraception available. These devices may be particularly appropriate for certain populations of women, including women who cannot use estrogen-containing contraception. Implants are safe for use by women with many chronic medical problems. The newest implant, Implanon (Organon International, Oss, The Netherlands), is the only device currently available in the United States and was approved in 2006. It is registered for 3 years of pregnancy prevention. Contraceptive implants have failure rates similar to tubal ligation, and yet they are readily reversible with a return to fertility within days of removal. Moreover, these contraceptive devices can be safely placed in the immediate postpartum period, ensuring good contraceptive coverage for women who may be at risk for an unintended pregnancy. Irregular bleeding is a common side effect for all progestin-only contraceptive implants. Preinsertion counseling should address possible side effects, and treatment may be offered to women who experience prolonged or frequent bleeding. Thieme Medical Publishers.

  10. Biphasic influence of dexamethasone exposure on embryonic vertebrate skeleton development

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Xin; Chen, Jian-long; Ma, Zheng-lai; Zhang, Zhao-long; Lv, Shun; Mai, Dong-mei; Liu, Jia-jia [Department of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, School of Medicine, Jinan University, Guangzhou 510632 (China); Chuai, Manli [Division of Cell and Developmental Biology, University of Dundee, Dundee DD1 5EH (United Kingdom); Lee, Kenneth Ka Ho; Wan, Chao [Stem Cell and Regeneration Thematic Research Programme, School of Biomedical Sciences, Chinese University of Hong Kong, Shatin (Hong Kong); Yang, Xuesong, E-mail: yang_xuesong@126.com [Department of Histology and Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, School of Medicine, Jinan University, Guangzhou 510632 (China); Institute of Fetal-Preterm Labor Medicine, Jinan University, Guangzhou 510632 (China)

    2014-11-15

    increased in mesenchymal cell mass treated by low concentration of Dex. Mmp-13 expression was obviously up-regulated by Dex in both mesenchymal cells and primary chondrocyte cultures. And Col10a1 expression was also increased by Dex exposure in chondrocyte. In summary, we have revealed that different concentrations of Dex exposure during early gestation could exert a biphasic effect on vertebrate skeletal development. - Highlights: • Chick embryos occurred shortening of the long bone following Dex exposure. • Dex suppressed chondrocytes proliferation and promoted apoptosis. • Dex exposure decreased ALP production and up-regulated Runx-2 and Mmp-13. • Dex exhibited biphasic effects on chondrogenic proliferation and nodule formation. • The hypertrophy and ossification were accelerated by Dex both in vivo and in vitro.

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

    Science.gov (United States)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Joint immobilization inhibits spontaneous hyaline cartilage regeneration induced by a novel double-network gel implantation.

    Science.gov (United States)

    Arakaki, Kazunobu; Kitamura, Nobuto; Kurokawa, Takayuki; Onodera, Shin; Kanaya, Fuminori; Gong, Jian-Ping; Yasuda, Kazunori

    2011-02-01

    We have recently discovered that spontaneous hyaline cartilage regeneration can be induced in an osteochondral defect in the rabbit, when we implant a novel double-network (DN) gel plug at the bottom of the defect. To clarify whether joint immobilization inhibits the spontaneous hyaline cartilage regeneration, we conducted this study with 20 rabbits. At 4 or 12 weeks after surgery, the defect in the mobile knees was filled with a sufficient volume of the hyaline cartilage tissue rich in proteoglycan and type-2 collagen, while no cartilage tissues were observed in the defect in the immobilized knees. Type-2 collagen, Aggrecan, and SOX9 mRNAs were expressed only in the mobile knees at each period. This study demonstrated that joint immobilization significantly inhibits the spontaneous hyaline cartilage regeneration induced by the DN gel implantation. This fact suggested that the mechanical environment is one of the significant factors to induce this phenomenon.

  19. Multi-scale osteointegration and neovascularization of biphasic calcium phosphate bone scaffolds

    Science.gov (United States)

    Lan, Sheeny K.

    Bone grafts are utilized clinically to guide tissue regeneration. Autologous bone and allogeneic bone are the current clinical standards. However, there are significant limitations to their use. To address the need for alternatives to autograft and allograft, researchers have worked to develop synthetic grafts, also referred to as scaffolds. Despite extensive efforts in this area, a gap persists between basic research and clinical application. In particular, solutions for repairing critical size and/or load-bearing defects are lacking. The aim of this thesis work was to address two critical barriers preventing design of successful tissue engineering constructs for bone regeneration within critical size and/or load-bearing defects. Those barriers are insufficient osteointegration and slow neovascularization. In this work, the effects of scaffold microporosity, recombinant human bone morphogenetic protein-2 delivery and endothelial colony forming cell vasculogenesis were evaluated in the context of bone formation in vivo. This was accomplished to better understand the role of these factors in bone regeneration, which may translate to improvements in tissue engineering construct design. Biphasic calcium phosphate (BCP) scaffolds with controlled macro- and microporosity were implanted in porcine mandibular defects. Evaluation of the BCP scaffolds after in vivo implantation showed, for the first time, osteocytes embedded in bone within scaffold micropores (regenerating bone and this has significant implications with regard to improved scaffold mechanical properties. The presence of osteocytes within scaffold micropores is an indication of scaffold osteoinductivity because a chemotactic factor must be present to induce cell migration into pores on the order of the cell diameter. It is likely that the scaffold undergoes in vivo modifications involving formation of a biological apatite layer within scaffold micropores and possibly co-precipitation of endogenous

  20. Comparison of monophasic and biphasic shocks for transthoracic cardioversion of atrial fibrillation

    NARCIS (Netherlands)

    M.F. Scholten (Marcoen); T. Szili-Torok (Tamas); L.J.L.M. Jordaens (Luc); A.P.J. Klootwijk (Peter)

    2003-01-01

    textabstractOBJECTIVE: To compare the efficacy of cardioversion in patients with atrial fibrillation between monophasic damped sine waveform and rectilinear biphasic waveform shocks at a high initial energy level and with a conventional paddle position. DESIGN: Prospective randomis

  1. Impact of pH and temperature on phase diagrams of different aqueous biphasic systems.

    Science.gov (United States)

    Chakraborty, Arabinda; Sen, Kamalika

    2016-02-12

    The phase diagrams of aqueous biphasic systems impart a distinct idea regarding the feasibility of biphase formation by different water soluble substances at their optimum concentrations. Depending on nature of the components viz., the water soluble polymers, surfactants, salts, amino acids or ionic liquids, a general trend of the biphase formation with varying temperature, pH and concentration has been studied over the recent years. This critical review is an endeavor to assess the general trends of these phase forming components to form biphasic systems with varying conditions of temperature and pH in light of the reported phase diagrams. Suitable explanations for the mechanisms of such behavior have been sorted out. The avenue yet to be explored has been addressed as these systems have a tremendous potential to be the future platform to solve different analytical issues.

  2. A closed-form solution of the three-dimensional contact problem for biphasic cartilage layers

    CERN Document Server

    Argatov, I I

    2010-01-01

    A three-dimensional unilateral contact problem for articular cartilage layers is considered in the framework of the biphasic cartilage model. The articular cartilages bonded to subchondral bones are modeled as biphasic materials consisting of a solid phase and a fluid phase. It is assumed that the subchondral bones are rigid and shaped like elliptic paraboloids. The obtained analytical solution is valid over long time periods and can be used for increasing loading conditions.

  3. Biphasic oxidation of oxy-hemoglobin in bloodstains.

    Directory of Open Access Journals (Sweden)

    Rolf H Bremmer

    Full Text Available BACKGROUND: In forensic science, age determination of bloodstains can be crucial in reconstructing crimes. Upon exiting the body, bloodstains transit from bright red to dark brown, which is attributed to oxidation of oxy-hemoglobin (HbO(2 to met-hemoglobin (met-Hb and hemichrome (HC. The fractions of HbO(2, met-Hb and HC in a bloodstain can be used for age determination of bloodstains. In this study, we further analyze the conversion of HbO(2 to met-Hb and HC, and determine the effect of temperature and humidity on the conversion rates. METHODOLOGY: The fractions of HbO(2, met-Hb and HC in a bloodstain, as determined by quantitative analysis of optical reflectance spectra (450-800 nm, were measured as function of age, temperature and humidity. Additionally, Optical Coherence Tomography around 1300 nm was used to confirm quantitative spectral analysis approach. CONCLUSIONS: The oxidation rate of HbO(2 in bloodstains is biphasic. At first, the oxidation of HbO(2 is rapid, but slows down after a few hours. These oxidation rates are strongly temperature dependent. However, the oxidation of HbO(2 seems to be independent of humidity, whereas the transition of met-Hb into HC strongly depends on humidity. Knowledge of these decay rates is indispensable for translating laboratory results into forensic practice, and to enable bloodstain age determination on the crime scene.

  4. Aqueous biphasic systems involving alkylsulfate-based ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Deive, Francisco J. [Instituto de Tecnologia Quimica e Biologica, UNL, Av. Republica, Apartado 127, 2780-901 Oeiras (Portugal); Department of Chemical Engineering, University of Vigo, P.O. Box 36310, Vigo (Spain); Rodriguez, Ana [Department of Chemical Engineering, University of Vigo, P.O. Box 36310, Vigo (Spain); Marrucho, Isabel M., E-mail: imarrucho@itqb.unl.pt [Instituto de Tecnologia Quimica e Biologica, UNL, Av. Republica, Apartado 127, 2780-901 Oeiras (Portugal); Rebelo, Luis P.N. [Instituto de Tecnologia Quimica e Biologica, UNL, Av. Republica, Apartado 127, 2780-901 Oeiras (Portugal)

    2011-11-15

    Highlights: > K{sub 3}PO{sub 4}, K{sub 2}CO{sub 3}, Na{sub 2}CO{sub 3}, and (NH{sub 4}){sub 2}SO{sub 4} act as phase promoter in aqueous solutions of ILs. > Remarkable influence of alkyl-chain length on solubility curves of alkylsulfate-based ILs. > Merchuck correlation was used for describing these systems. > {Delta}S{sub hyd} and Hofmeister series were used to discuss the different salting out effects. - Abstract: The specific effects of K{sub 3}PO{sub 4}, K{sub 2}CO{sub 3}, Na{sub 2}CO{sub 3}, and (NH{sub 4}){sub 2}SO{sub 4}, as high charge-density inorganic salts and thus inducers of the formation of aqueous biphasic systems (ABS) containing several ethyl-methylimidazolium alkylsulfate ionic liquids, C{sub 2}MIM C{sub n}SO{sub 4} (n = 2, 4, 6, or 8), have been assessed at T = 298.15 K. The results are analyzed in the light of the Hofmeister series. The influence of different alkyl chain lengths in the anion, together with the ability of the selected inorganic salts to induce the formation of ABS, is discussed. Phase diagrams have been determined through turbidimetry, including tie lines assignments from mass phase ratios according to the lever - arm rule. The Merchuck equation was satisfactorily used to correlate the solubility curve.

  5. RADIOGRAPHIC IMAGING OF BIPHASIC SYNOVIAL SARCOMA ON LEFT ELBOW

    Directory of Open Access Journals (Sweden)

    Sitanggang Firman P

    2013-04-01

    Full Text Available Synovial sarcoma is the fourth most common type of sarcoma. It represents between 5% -10% of all soft tissue sarcomas and most prevalent in aged between 15 - 40 years. Synovial sarcoma is the most commonly misdiagnosed soft tissue malignancy, initially as an inflammation process,often because it may be slow-growing, have a benign appearance on imaging studies, may vary in size, and may have pain similar to that associated with trauma.    A rare case is presented of 17 years old women with a synovial sarcoma biphasic. The primary tumor originated in the left elbow since 2004. Since then, the patient has had repeated passive or active left elbow pain and tenderness. No history of trauma. She has not developed metastases of the lung. The patient refused to have surgery and others medical procedures that already planned and explained to her. The conclusion of this case report point that radiology is important to diagnosis and planning for further management

  6. Biphasic flow: structure and upscaling, consequences on macroscopic transport properties

    CERN Document Server

    Toussaint, Renaud; Méheust, Yves; Løvoll, Grunde; Jankov, Mihailo; Schäfer, Gerhard; Schmittbuhl, Jean

    2012-01-01

    In disordered porous media, two-phase flow of immiscible fluids (biphasic flow) is organized in patterns that sometimes exhibit fractal geometries over a range of length scales, depending on the capillary, gravitational and viscous forces at play. These forces, as well as the boundary conditions, also determine whether the flow leads to the appearance of fingering pathways, i.e., unstable flow, or not. We present here a short review of these aspects, focusing on drainage and summarizing when these flows are expected to be stable or not, what fractal dimensions can be expected, and in which range of scales. We base our review on experimental studies performed in two-dimensional Hele-Shaw cells, or addressing three dimensional porous media by use of several imaging techniques. We first present configurations in which solely capillary forces and gravity play a role. Next, we review configurations in which capillarity and viscosity are the main forces at play. Eventually, we examine how the microscopic geometry o...

  7. Biphasic regulation of lysosomal exocytosis by oxidative stress.

    Science.gov (United States)

    Ravi, Sreeram; Peña, Karina A; Chu, Charleen T; Kiselyov, Kirill

    2016-11-01

    Oxidative stress drives cell death in a number of diseases including ischemic stroke and neurodegenerative diseases. A better understanding of how cells recover from oxidative stress is likely to lead to better treatments for stroke and other diseases. The recent evidence obtained in several models ties the process of lysosomal exocytosis to the clearance of protein aggregates and toxic metals. The mechanisms that regulate lysosomal exocytosis, under normal or pathological conditions, are only beginning to emerge. Here we provide evidence for the biphasic effect of oxidative stress on lysosomal exocytosis. Lysosomal exocytosis was measured using the extracellular levels of the lysosomal enzyme beta-hexosaminidase (ß-hex). Low levels or oxidative stress stimulated lysosomal exocytosis, but inhibited it at high levels. Deletion of the lysosomal ion channel TRPML1 eliminated the stimulatory effect of low levels of oxidative stress. The inhibitory effects of oxidative stress appear to target the component of lysosomal exocytosis that is driven by extracellular Ca(2+). We propose that while moderate oxidative stress promotes cellular repair by stimulating lysosomal exocytosis, at high levels oxidative stress has a dual pathological effect: it directly causes cell damage and impairs damage repair by inhibiting lysosomal exocytosis. Harnessing these adaptive mechanisms may point to pharmacological interventions for diseases involving oxidative proteotoxicity or metal toxicity.

  8. A biphasic theory for the viscoelastic behaviors of vocal fold lamina propria in stress relaxation.

    Science.gov (United States)

    Zhang, Yu; Czerwonka, Lukasz; Tao, Chao; Jiang, Jack J

    2008-03-01

    In this study, a biphasic theory is applied to investigate the viscoelastic behaviors of vocal fold lamina propria during stress relaxation. The vocal fold lamina propria tissue is described as a biphasic material composed of a solid phase and an interstitial fluid phase. The biphasic theory reveals the interaction between the solid and the fluid. For the one-dimensional case, the analytical solutions of solid displacement, fluid velocity, and stress are derived. The biphasic theory predicts the stress relaxation of the vocal fold lamina propria. The quasilinear viscoelastic model as well as its higher-order elastic parameters can be derived from this biphasic theory. Furthermore, the fluid is found to support the majority of the stress at the early stage of stress relaxation; however, when the time becomes sufficiently large, the solid eventually bears all the stress. The early fluid stress support is much higher than the eventual solid support and may be important for understanding the effects of dehydration on tissue damage. By considering the solid-fluid structure of the vocal fold lamina propria, the biphasic theory allows for a more physical theory of tissue viscoelasticity than a single phase solid description and may provide a valuable physical mechanism for the observed vocal fold rheologic behaviors.

  9. A mixed-penalty biphasic finite element formulation incorporating viscous fluids and material interfaces.

    Science.gov (United States)

    Chan, B; Donzelli, P S; Spilker, R L

    2000-06-01

    The fluid viscosity term of the fluid phase constitutive equation and the interface boundary conditions between biphasic, solid and fluid domains have been incorporated into a mixed-penalty finite element formulation of the linear biphasic theory for hydrated soft tissue. The finite element code can now model a single-phase viscous incompressible fluid, or a single-phase elastic solid, as limiting cases of a biphasic material. Interface boundary conditions allow the solution of problems involving combinations of biphasic, fluid and solid regions. To incorporate these conditions, the volume-weighted mixture velocity is introduced as a degree of freedom at interface nodes so that the kinematic continuity conditions are satisfied by conventional finite element assembly techniques. Results comparing our numerical method with an independent, analytic solution for the problem of Couette flow over rigid and deformable porous biphasic layers show that the finite element code accurately predicts the viscous fluid flows and deformation in the porous biphasic region. Thus, the analysis can be used to model the interface between synovial fluid and articular cartilage in diarthrodial joints. This is an important step toward modeling and understanding the mechanisms of joint lubrication and another step toward fully modeling the in vivo behavior of a diarthrodial joint.

  10. Biphasic Polyurethane/Polylactide Sponges Doped with Nano-Hydroxyapatite (nHAp Combined with Human Adipose-Derived Mesenchymal Stromal Stem Cells for Regenerative Medicine Applications

    Directory of Open Access Journals (Sweden)

    Krzysztof Marycz

    2016-10-01

    Full Text Available Cartilage and bone tissue injuries are common targets in regenerative medicine. The degeneration of cartilage tissue results in tissue loss with a limited ability to regenerate. However, the application of mesenchymal stem cells in the course of such condition makes it possible to manage this disorder by improving the structure of the remaining tissue and even stimulating its regeneration. Nevertheless, in the case of significant tissue loss, standard local injection of cell suspensions is insufficient, due to the low engraftment of transplanted cells. Introduction of mesenchymal stem cells on the surface of a compatible biomaterial can be a promising tool for inducing the regeneration by both retaining the cells at the desired site and filling the tissue gap. In order to obtain such a cell-biomaterial hybrid, we developed complex, biphasic polymer blend biomaterials composed of various polyurethane (PU-to-polylactide (PLA ratios, and doped with different concentrations of nano-hydroxyapatite (nHAp. We have determined the optimal blend composition and nano-hydroxyapatite concentration for adipose mesenchymal stem cells cultured on the biomaterial. We applied biological in vitro techniques, including cell viability assay, determination of oxidative stress factors level, osteogenic and chondrogenic differentiation potentials as well as cell proteomic analysis. We have shown that the optimal composition of biphasic scaffold was 20:80 of PU:PLA with 20% of nHAp for osteogenic differentiation, and 80:20 of PU:PLA with 10% of nHAp for chondrogenic differentiation, which suggest the optimal composition of final biphasic implant for regenerative medicine applications.

  11. Electrospun vancomycin-loaded coating on titanium implants for the prevention of implant-associated infections

    Directory of Open Access Journals (Sweden)

    Zhang L

    2014-06-01

    Full Text Available Li Zhang,* Junwei Yan,* Zhaowei Yin, Cheng Tang, Yang Guo, Dong Li, Bo Wei, Yan Xu, Qiangrong Gu, Liming Wang Orthopedic Laboratory of Nanjing First Hospital, Nanjing Medical University, Nanjing, People’s Republic of China *Both of these authors contributed equally to this work Abstract: The objectives of this work were to develop an antibiotic coating on the surface of a titanium plate to determine its antibacterial properties in vitro and in vivo. To prepare vancomycin-coated titanium implants, we adopted the electrospinning nanotechnique. The surface structure of the coating implants was observed using a scanning electron microscope. An elution method and a high-pressure liquid chromatography assay were used to characterize the release behavior of vancomycin from the coating. The antibacterial efficacy and the cytotoxicity of the coated titanium implants on osteoblasts were investigated in vitro. In addition, X-ray, white blood cell count, C-reactive protein, erythrocyte sedimentation rate, and pathological examination were performed to validate its antimicrobial efficacy in vivo. The antibiotic coating released 82.7% (approximately 528.2 µg of total vancomycin loading in the coating in vitro. The release behavior of vancomycin from nanofiber coatings exhibited a biphasic release pattern with an initial burst on day 1, followed by a slow and controlled release over 28 days. There was no cytotoxicity observed in vitro for the vancomycin-loaded coating. The vancomycin-coated titanium implants were active in treating implant-associated infection in vivo. Thus, vancomycin-coated titanium implants may be a promising approach to prevent and treat implant-associated infections. Keywords: electrospinning, vancomycin, implant, infection, coating, nanofibers

  12. Fate of bone marrow mesenchymal stem cells following the allogeneic transplantation of cartilaginous aggregates into osteochondral defects of rabbits.

    Science.gov (United States)

    Yoshioka, Tomokazu; Mishima, Hajime; Kaul, Zeenia; Ohyabu, Yoshimi; Sakai, Shinsuke; Ochiai, Naoyuki; Kaul, Sunil C; Wadhwa, Renu; Uemura, Toshimasa

    2011-06-01

    The purpose of this study was to track mesenchymal stem cells (MSCs) labelled with internalizing quantum dots (i-QDs) in the reparative tissues, following the allogeneic transplantation of three-dimensional (3D) cartilaginous aggregates into the osteochondral defects of rabbits. QDs were conjugated with a unique internalizing antibody against a heat shock protein-70 (hsp70) family stress chaperone, mortalin, which is upregulated and expressed on the surface of dividing cells. The i-QDs were added to the culture medium for 24 h. Scaffold-free cartilaginous aggregates formed from i-QD-labelled MSCs (i-MSCs), using a 3D culture system with chondrogenic supplements for 1 week, were transplanted into osteochondral defects of rabbits. At 4, 8 and 26 weeks after the transplantation, the reparative tissues were evaluated macroscopically, histologically and fluoroscopically. At as early as 4 weeks, the defects were covered with a white tissue resembling articular cartilage. In histological appearance, the reparative tissues resembled hyaline cartilage on safranin-O staining throughout the 26 weeks. In the deeper portion, subchondral bone and bone marrow were well remodelled. On fluoroscopic evaluation, QDs were tracked mainly in bone marrow stromata, with some signals detected in cartilage and the subchondral bone layer. We showed that the labelling of rabbit MSCs with anti-mortalin antibody-conjugated i-QDs is a tolerable procedure and provides a stable fluorescence signal during the cartilage repair process for up to 26 weeks after transplantation. The results suggest that i-MSCs did not inhibit, and indeed contributed to, the regeneration of osteochondral defects.

  13. Modyfied wedge osteotomy for osteoarthritis of elbow secondary to osteochondritis dissecans in adolecent with multiple epiphyseal dysplasia. A case report.

    Science.gov (United States)

    Yoshida, Takashi; Kim, Wook-Cheol; Oka, Yoshinobu; Nakase, Masashi; Nishida, Atsushi; Wada, Hiroaki; Arai, Yuji; Kubo, Toshikazu

    2017-12-01

    Multiple epiphyseal dysplasia (MED) may be complicated by osteochondritis dissecans (OCD), most commonly reported in the knee, but involvement of the elbow is very rare. Optimal treatment for MED-associated elbow OCD and treatment outcome have not been established. This report describes the case of an adolescent male patient with elbow OCD treated by arthroscopic drilling at a previous clinic. Progression of osteoarthritis and radial head subluxation were observed. Resection of the osteophytes and modified wedge osteotomy of the lateral condyle were then performed, and a favorable result was obtained by decompression and sufficient congruency of the radiohumeral joint.

  14. Gold implant therapy of locomotory disorders in dogs - Case studies

    Directory of Open Access Journals (Sweden)

    Emilia Abrudean

    2016-06-01

    Full Text Available The case study was conducted between October and January 2015, on 7 dogs of different breeds and ages, which at clinical examination showed varying degrees of lameness. The dogs behavior and state of consciousness, their attitude in standing, decubitus and at walk and the presence of involuntary movements was assessed through inspection. Palpation was used to feel muscular tonus, local temperature and sensibility. Postural reactions were highlighted by carrying out forced positions of each limb, thus highlighting the proprioceptive sensitivity. By testing the spinal reflexes the reactions of the forelimbs and hind limbs were evaluated, seeking the state of normality, or the absence, diminution or exacerbation of these reflexes. Also, diagnostic imaging was performed consisting of simple radiographs, were performed for the cases that entered the clinic. In the case of digital X-rays, X-rays are passing through the subject being examined are filtered, then touch a plate of sensors able to convert signals generated into digital information with an image appear on the computer screen. Interpretation of results was done by assessing the degree of dysplasia, and the Norberg-Olson angle and stage. This study used digital radiography as imaging technique; the device was Rx-M EVO Fujifilm. On the basis of diagnostic imaging and computerized image, diagnosis was established for each case. The treatment protocol with gold implant was the same for all seven cases; the adopted procedure was the "Wiener" procedure, described by Kasper and Zohmann. The procedure began with establishing a set of points associated with the treatment of hip dysplasia, spondylosis, arthritis, and osteochondritis. For the therapeutic protocol to be performed correctly took the dogs were sedated. This was done with medetomidine hydrochloride (Dorbene vet, Pfizer, concentration 1 mg⁄ml, administered in a 0,1mg⁄kg body weight dose. The results were visible after a month from the

  15. Cochlear Implant

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In this text, the authors recall the main principles and data ruling cochlear implants. Then, a first circle of technical equipment for assistance is presented. This circle includes: device setting (DS), Electrically evoked Auditory Brainstem Responses (EABR), Neural Response Telemetry (NRT), Stapedial Reflex (SR) and Electrodogram Acquisition (EA). This first cycle becomes more and more important as children are implanted younger and younger; the amount of data available with this assistance makes necessary the use of models (implicit or explicit) to handle this information. Consequently, this field is more open than ever.

  16. Design and evaluation of lornoxicam bilayered tablets for biphasic release

    Directory of Open Access Journals (Sweden)

    Songa Ambedkar Sunil

    2012-12-01

    Full Text Available The objective of the present investigation was to develop bilayered tablets of lornoxicam to achieve biphasic release pattern. A bilayered tablet, consisting of an immediate and controlled release layer, was prepared by direct compression technique. The controlled release effect was achieved by using various hydrophilic natural, semi synthetic and synthetic controlled release polymers such as xanthan gum, hydroxypropyl methylcellulose (HPMC and polyethylene oxide (PEO to modulate the release of the drug. The in vitro drug release profiles showed the biphasic release behavior in which the immediate release (IR layer containing the lornoxicam was released within 15 minutes, whereas the controlled release (CR layer controlled the drug release for up to 24 h. All the bilayered tablets formulated have followed the zero order release with non-Fickian diffusion controlled release mechanism after the initial burst release. FTIR studies revealed that there was no interaction between the drug and polymers used in the study. Statistical analysis (ANOVA showed no significant difference in the cumulative amount of drug release after 15 min, but significant difference (p O objetivo do presente trabalho foi desenvolver comprimidos bicamada de lornoxicam para atingir padrão de liberação bifásica. Preparou-se, por compressão direta, comprimido bicamada, consistindo de uma camada de liberação imediata e uma de liberação controlada. A liberação controlada foi obtida pelo uso de vários polímeros naturais hidrofílicos, semi-sintéticos e sintéticos, tais como goma xantana, hidroxipropilmetil celulose (HPMC e óxido de polietileno (PEO para modular a liberação do fármaco. Os perfis de liberação in vitro mostraram comportamento bifásico em que a camada de liberação imediata (IR contendo lornoxicam foi liberada em 15 minutos, enquanto a camada de liberação controlada (CR liberou o fármaco em mais de 24 horas, Todos os comprimidos bicamada

  17. Unique Anatomic Feature of the Posterior Cruciate Ligament in Knees Associated With Osteochondritis Dissecans

    Science.gov (United States)

    Ishikawa, Masakazu; Adachi, Nobuo; Yoshikawa, Masahiro; Nakamae, Atsuo; Nakasa, Tomoyuki; Ikuta, Yasunari; Hayashi, Seiju; Deie, Masataka; Ochi, Mitsuo

    2016-01-01

    Background: Osteochondritis dissecans (OCD) of the knee is a disorder in juveniles and young adults; however, its etiology still remains unclear. For OCD at the medial femoral condyle (MFC), it is sometimes observed that the lesion has a connection with fibers of the posterior cruciate ligament (PCL). Although this could be important information related to the etiology of MFC OCD, there is no report examining an association between the MFC OCD and the PCL anatomy. Purpose: To investigate the anatomic features of knees associated with MFC OCD, focusing especially on the femoral attachment of the PCL, and to compare them with knees associated with lateral femoral condyle (LFC) OCD and non-OCD lesions. Study Design: Case-control study; Level of evidence, 3. Methods: We retrospectively reviewed 39 patients (46 knees) with OCD lesions who had undergone surgical treatment. Using magnetic resonance imaging (MRI) scans, the PCL attachment at the lateral wall of the MFC was measured on the coronal sections, and the knee flexion angle was also measured on the sagittal sections. As with non-OCD knees, we reviewed and analyzed 25 knees with anterior cruciate ligament (ACL) injuries and 16 knees with meniscal injuries. Results: MRIs revealed that the femoral PCL footprint was located in a significantly more distal position in the patients with MFC OCD compared with patients with LFC OCD and ACL and meniscal injuries. There was no significant difference in knee flexion angle among the 4 groups. Conclusion: The PCL in patients with MFC OCD attached more distally at the lateral aspect of the MFC compared with knees with LFC OCD and ACL and meniscal injuries. PMID:27294170

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  19. Stage-I osteochondritis dissecans versus normal variants of ossification in the knee in children

    Energy Technology Data Exchange (ETDEWEB)

    Gebarski, Kathleen; Hernandez, Ramiro J. [University of Michigan Health System, C.S. Mott Children' s Hospital, Ann Arbor, MI (United States)

    2005-09-01

    Juvenile osteochondritis dissecans (OCD) has a better prognosis than the adult type. We postulated that the excellent prognosis of juvenile OCD could be explained, at least in part, by the erroneous diagnosis of some developmental variants of ossification as stage-I OCD. Knee MRIs of 38 children, ages 7.5-17.7 years (mean and median age 13 years), were retrospectively reviewed to look for features that might separate normal variants of ossification from stage-I OCD. These included age, gender, site, configuration of the lesion, residual cartilaginous model and presence of edema. Twenty-three patients (32 condyles) had ossification defects with intact articular cartilage suggestive of stage-I lesions. No stage-II lesions were seen in the posterior femoral condyles. Accessory ossification centers were seen in 11/16 posterior condyles and 3/16 central condyles. Spiculation of existing ossification was seen in 12/16 posterior condylar lesions and 1/16 central condyles. There was a predominance of accessory ossifications and spiculations in the patients with 10% or greater residual cartilaginous model. No edema signal greater than diaphyseal red-marrow signal was seen in the posterior condyles. Clinical follow-up ranged from 0.5 to 38 months, with clinical improvement in 22 out of 23 patients. Inclusion of normal variants in the stage-I OCD category might explain, in part, the marked difference in published outcome between the juvenile and adult forms of OCD. Ossification defects in the posterior femoral condyles with intact overlying articular cartilage, accessory ossification centers, spiculation, residual cartilaginous model, and lack of bone-marrow edema are features of developmental variants rather than OCD. (orig.)

  20. 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.

  1. Osteochondral fragmentation of the distal aspect of the patella in horses.

    Science.gov (United States)

    McIlwraith, C W

    1990-05-01

    A condition characterised by osteochondral fragmentation of the distal aspect of the patella in 15 horses is described. The problem was unilateral in six horses and bilateral in nine. There were eight Quarterhorses, three Thoroughbreds, two American Saddlebreds, one American Paint and one Warmblood-Thoroughbred cross. A previous medial patellar desmotomy had been performed on 12 of the 15 horses. The condition manifested as hindlimb lameness and stiffness ranging from mild to severe. There was fibrous thickening in the stifle area in the 12 cases with a previous medial patellar desmotomy, and synovial effusion in seven of 12 cases. Synovial effusion was present in two of the three cases in which a previous medial patellar desmotomy was not performed. The radiographic changes included bony fragmentation, spurring (with or without an associated subchondral defect), subchondral roughening and subchondral lysis of the distal aspect of the patella. All horses were treated with arthroscopic surgery. The lesions at arthroscopy varied from flaking, fissuring, undermining or fragmentation of the articular cartilage to fragmentation or lysis of the bone at the distal aspect of the patella. The subchondral bone was involved in all cases that had a previous medial patellar desmotomy. Of the 12 horses that had a previous medial patellar desmotomy, eight became sound at their intended use, one was sold in training without problems, one is in early training without problems, one never improved and one is in convalescence. Of the three that did not have a patellar desmotomy, two performed their intended use well but one was unsatisfactory.

  2. Osteocondrite dissecante bilateral de joelho em jogador de basquetebol: relato de caso Bilateral osteochondritis dissecans of the knee in a basketball player: case report

    Directory of Open Access Journals (Sweden)

    Jorge Sayum Filho

    2012-04-01

    Full Text Available Os autores relatam um caso de osteocondrite dissecante em joelho bilateral de um jogador de basquetebol de 17 anos que foi diagnosticado e tratado conforme a literatura.The authors report a case of bilateral osteochondritis dissecans in a 17-year-old basketball player who was diagnosed and treated as shown in the literature.

  3. Expression of colony-stimulating factor 1 is associated with occurrence of osteochondral change in pigmented villonodular synovitis.

    Science.gov (United States)

    Ota, Takehiro; Urakawa, Hiroshi; Kozawa, Eiji; Ikuta, Kunihiro; Hamada, Shunsuke; Tsukushi, Satoshi; Shimoyama, Yoshie; Ishiguro, Naoki; Nishida, Yoshihiro

    2015-07-01

    Pigmented villonodular synovitis (PVNS) is a benign, translocation-derived neoplasm. Because of its high local recurrence rate after surgery and occurrence of osteochondral destruction, a novel therapeutic target is required. The present study aimed to evaluate the significance of protein expression possibly associated with the pathogenesis during the clinical course of PVNS. In 40 cases of PVNS, positivity of colony-stimulated factor 1 (CSF1), its receptor (CSF1R), and receptor activator of nuclear factor kappa-B ligand (RANKL) were immunohistochemically determined. The relationship between the positivity and clinical outcomes was investigated. High positivity of CSF1 staining intensity was associated with an increased incidence of osteochondral lesions (bone erosion and osteoarthritis) (p = 0.009), but not with the rate of local recurrence. Positivity of CSF1R and RANKL staining was not associated with any clinical variables. The number of giant cells was not correlated with positivity of any of the three proteins, or with the clinical outcome. Focusing on knee cases, CSF1 positivity was also associated with the incidence of osteochondal change (p = 0.02). CSF1R positivity was high in cases which had local recurrence, but not significantly so (p = 0.129). Determination of CSF1 and CSF1R expression may be useful as a prognosticator of the clinical course and/or outcomes of PVNS.

  4. All-Arthroscopic Autologous Matrix-Induced Chondrogenesis for the Treatment of Osteochondral Lesions of the Talus

    Science.gov (United States)

    Usuelli, Federico Giuseppe; de Girolamo, Laura; Grassi, Miriam; D'Ambrosi, Riccardo; Montrasio, Umberto Alfieri; Boga, Michele

    2015-01-01

    Several surgical techniques have been described for the treatment of talar chondral lesions. Among them, microfracture is well established. Autologous matrix-induced chondrogenesis (AMIC), using microfracture and biomaterials, has shown promising results for the treatment of knee osteochondral lesions and has been proposed for the ankle as an open technique. We describe an all-arthroscopic AMIC technique. The benefits of an all-arthroscopic procedure include smaller incisions with less soft-tissue dissection, better visualization of the joint, and a quicker recovery compared with open surgery. The use of matrix to support cartilage regeneration promotes good-quality cartilage tissue with satisfactory long-term outcomes. Our all-arthroscopic AMIC technique uses a type I–type III porcine collagen matrix (Chondro-Gide; Geistlich Pharma, Wolhusen, Switzerland) and is characterized by 2 different arthroscopic surgical phases. First, adequate exposure is achieved through use of a Hintermann spreader (Integra LifeSciences, Plainsboro, NJ) with sufficient joint distraction and wet lesion preparation. The second surgical step is performed dry, involving matrix placement and fixation. The all-arthroscopic AMIC technique for the treatment of osteochondral lesions of the talus allows a very precise reconstruction in the case of cartilage defects and avoids the need for a more invasive operation associated with higher morbidity and a longer surgical time. PMID:26258040

  5. 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.

  6. Combined autologous chondrocyte implantation (ACI with supra-condylar femoral varus osteotomy, following lateral growth-plate damage in an adolescent knee: 8-year follow-up

    Directory of Open Access Journals (Sweden)

    Vijayan Sridhar

    2011-03-01

    Full Text Available Abstract We report the 8-year clinical and radiographic outcome of an adolescent patient with a large osteochondral defect of the lateral femoral condyle, and ipsilateral genu valgum secondary to an epiphyseal injury, managed with autologous chondrocyte implantation (ACI and supracondylar re-alignment femoral osteotomy. Long-term clinical success was achieved using this method, illustrating the effective use of re-alignment osteotomy in correcting mal-alignment of the knee, protecting the ACI graft site and providing the optimum environment for cartilage repair and regeneration. This is the first report of the combined use of ACI and femoral osteotomy for such a case.

  7. Outcome of combined autologous chondrocyte implantation and anterior cruciate ligament reconstruction

    Directory of Open Access Journals (Sweden)

    Baljinder S Dhinsa

    2015-01-01

    Full Text Available Background: Instability of the knee joint, after anterior cruciate ligament (ACL injury, is contraindication to osteochondral defect repair. This prospective study is to investigate the role of combined autologous chondrocyte implantation (ACI with ACL reconstruction. Materials and Methods: Three independent groups of patients with previous ACL injuries undergoing ACI were identified and prospectively followed up. The first group had ACI in combination with ACL reconstruction (combined group; the 2 nd group consisted of individuals who had an ACI procedure having had a previously successful ACL reconstruction (ACL first group; and the third group included patients who had an ACI procedure to a clinically stable knee with documented nonreconstructed ACL disruption (No ACL group. Their outcomes were assessed using the modified cincinnati rating system, the Bentley functional (BF rating system (BF and a visual analog scale (VAS. Results: At a mean followup of 64.24 months for the ACL first group, 63 months for combined group and 78.33 months for the No ACL group; 60% of ACL first patients, 72.73% of combined group and 83.33% of the No ACL group felt their outcome was better following surgery. There was no significant difference demonstrated in BF and VAS between the combined and ACL first groups. Results revealed a significant affect of osteochondral defect size on outcome measures. Conclusion: The study confirms that ACI in combination with ACL reconstruction is a viable option with similar outcomes as those patients who have had the procedures staged.

  8. Hard implant coatings with antimicrobial properties.

    Science.gov (United States)

    Moseke, Claus; Gbureck, Uwe; Elter, Patrick; Drechsler, Peter; Zoll, Andreas; Thull, Roger; Ewald, Andrea

    2011-12-01

    Infection of orthopaedic implants often leads to inflammation immediately after surgery and increases patient morbidity due to repetitive operations. Silver ions have been shown to combine good biocompatibility with a low risk of inducing bacterial resistance. In this study a physical vapour deposition system using both arc deposition and magnetron sputtering has been utilized to produce silver ion doped TiN coatings on Ti substrates. This biphasic system combines the advantages of silver induced bactericidity with the good mechanical properties of TiN. Crystallographic analysis by X-ray diffraction showed that silver was deposited as well in its elementary form as it was incorporated into the crystal lattice of TiN, which resulted in increasing hardness of the TiN-coatings. Elution experiments revealed a continuous release of Ag ions in phosphate buffered saline. The coatings showed significant inhibitory effects on the growth of Staphylococcus epidermidis and Staphylococcus aureus and practically no cell-toxicity in cytocompatibility tests.

  9. Short Implants: New Horizon in Implant Dentistry.

    Science.gov (United States)

    Jain, Neha; Gulati, Manisha; Garg, Meenu; Pathak, Chetan

    2016-09-01

    The choice of implant length is an essential factor in deciding the survival rates of these implants and the overall success of the prosthesis. Placing an implant in the posterior part of the maxilla and mandible has always been very critical due to poor bone quality and quantity. Long implants can be placed in association with complex surgical procedures such as sinus lift and bone augmentation. These techniques are associated with higher cost, increased treatment time and greater morbidity. Hence, there is need for a less invasive treatment option in areas of poor bone quantity and quality. Data related to survival rates of short implants, their design and prosthetic considerations has been compiled and structured in this manuscript with emphasis on the indications, advantages of short implants and critical biomechanical factors to be taken into consideration when choosing to place them. Studies have shown that comparable success rates can be achieved with short implants as those with long implants by decreasing the lateral forces to the prosthesis, eliminating cantilevers, increasing implant surface area and improving implant to abutment connection. Short implants can be considered as an effective treatment alternative in resorbed ridges. Short implants can be considered as a viable treatment option in atrophic ridge cases in order to avoid complex surgical procedures required to place long implants. With improvement in the implant surface geometry and surface texture, there is an increase in the bone implant contact area which provides a good primary stability during osseo-integration.

  10. Bi-phasic Simulation of Metal Injection Moulding:Constitutive Determinations

    Institute of Scientific and Technical Information of China (English)

    Liu Baosheng(柳葆生); Barriere Thierry; Gelin Jean-Claude

    2003-01-01

    To predict the segregation effect in metal injection moulding (MIM) injection, a bi-phasic model based on mixture theory is adopted in simulation. An explicit algorithm is developed and realized by the authors, which conducts the simulation to be a cost-effective tool in MIM technology. In case of the bi-phasic simulation, the viscosity behaviours are necessary to be determined for the flows of each phase while only the viscosity of mixture is measurable by tests. It is a crucial problem for application of the bi-phasic simulation of MIM injection. A reasonable method is hence analysed and proposed to determine the viscosity behaviours of each phase. Even though this method may be furthermore modified in the future, it results in the practical simulation of segregation effects with reasonable parameters. The simulation results are compared with the measurements on injected specimens.

  11. Apomorphine-induced biphasic circling behaviour in 6-hydroxydopamine-lesioned rats. A pharmacological kindling phenomenon.

    Science.gov (United States)

    Coward, D M

    1983-06-01

    Factors governing the development of apomorphine-induced biphasic circling behaviour in rats having unilateral 6-hydroxydopamine lesions of the substantia nigra were investigated. It was found that a post-lesion time of at least 2--3 weeks and the repeated exposure to apomorphine were essential for its development. Optimal results were obtained when animals received weekly apomorphine, 0.05 mg/kg sc, in post-lesion weeks 6, 7 and 8. Pretreatment with haloperidol, 1.0 and 2.0 mg/kg ip 1 h beforehand in post-lesion week 9, converted the biphasic response into an enhanced, uniphasic one. The findings suggest that the development of the biphasic response to apomorphine is a multi-factorial process representing a pharmacological kindling phenomenon.

  12. Shock-induced termination of reentrant cardiac arrhythmias: Comparing monophasic and biphasic shock protocols

    Energy Technology Data Exchange (ETDEWEB)

    Bragard, Jean, E-mail: jbragard@unav.es; Simic, Ana; Elorza, Jorge [Department of Physics and Applied Math., University of Navarra, Pamplona (Spain); Grigoriev, Roman O.; Fenton, Flavio H. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Cherry, Elizabeth M. [School of Mathematical Sciences, Rochester Institute of Technology, Rochester, New York 14623 (United States); Gilmour, Robert F. [University of Prince Edward Island, Charlottetown C1A 4P3 (Canada); Otani, Niels F. [School of Mathematical Sciences, Rochester Institute of Technology, Rochester, New York 14623 (United States); Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853 (United States)

    2013-12-15

    In this article, we compare quantitatively the efficiency of three different protocols commonly used in commercial defibrillators. These are based on monophasic and both symmetric and asymmetric biphasic shocks. A numerical one–dimensional model of cardiac tissue using the bidomain formulation is used in order to test the different protocols. In particular, we performed a total of 4.8 × 10{sup 6} simulations by varying shock waveform, shock energy, initial conditions, and heterogeneity in internal electrical conductivity. Whenever the shock successfully removed the reentrant dynamics in the tissue, we classified the mechanism. The analysis of the numerical data shows that biphasic shocks are significantly more efficient (by about 25%) than the corresponding monophasic ones. We determine that the increase in efficiency of the biphasic shocks can be explained by the higher proportion of newly excited tissue through the mechanism of direct activation.

  13. Therapeutic efficacy of endostatin exhibits a biphasic dose-response curve.

    Science.gov (United States)

    Celik, Ilhan; Sürücü, Oguzkan; Dietz, Carsten; Heymach, John V; Force, Jeremy; Höschele, Iris; Becker, Christian M; Folkman, Judah; Kisker, Oliver

    2005-12-01

    We show here that recombinant endostatin protein has a biphasic effect on the inhibition of endothelial cell migration in vitro. In tumor-bearing animals, there is a similar biphasic effect on the inhibition of tumor growth and on circulating endothelial cells after once-daily s.c. injections. This biphasic effect is revealed as a U-shaped curve in which efficacy is optimal between very low and very high doses depending on the tumor type. This result may be applicable to other inhibitors of endothelial growth and to angiogenesis. Furthermore, these results have important implications for clinicians who administer angiogenesis inhibitors for cancer or other angiogenesis-dependent diseases. When these results are taken together with two previous reports of angiogenesis inhibitors with a U-shaped dose-response, they suggest that other regulators of endothelial growth may display a similar pattern.

  14. Biphasic Dependence of Glioma Survival and Cell Migration on CD44 Expression Level.

    Science.gov (United States)

    Klank, Rebecca L; Decker Grunke, Stacy A; Bangasser, Benjamin L; Forster, Colleen L; Price, Matthew A; Odde, Thomas J; SantaCruz, Karen S; Rosenfeld, Steven S; Canoll, Peter; Turley, Eva A; McCarthy, James B; Ohlfest, John R; Odde, David J

    2017-01-03

    While several studies link the cell-surface marker CD44 to cancer progression, conflicting results show both positive and negative correlations with increased CD44 levels. Here, we demonstrate that the survival outcomes of genetically induced glioma-bearing mice and of high-grade human glioma patients are biphasically correlated with CD44 level, with the poorest outcomes occurring at intermediate levels. Furthermore, the high-CD44-expressing mesenchymal subtype exhibited a positive trend of survival with increased CD44 level. Mouse cell migration rates in ex vivo brain slice cultures were also biphasically associated with CD44 level, with maximal migration corresponding to minimal survival. Cell simulations suggest that cell-substrate adhesiveness is sufficient to explain this biphasic migration. More generally, these results highlight the potential importance of non-monotonic relationships between survival and biomarkers associated with cancer progression.

  15. Dissolved nutrients and atrazine removal by column-scale monophasic and biphasic rain garden model systems.

    Science.gov (United States)

    Yang, Hanbae; McCoy, Edward L; Grewal, Parwinder S; Dick, Warren A

    2010-08-01

    Rain gardens are bioretention systems that have the potential to reduce peak runoff flow and improve water quality in a natural and aesthetically pleasing manner. We compared hydraulic performance and removal efficiencies of nutrients and atrazine in a monophasic rain garden design versus a biphasic design at a column-scale using simulated runoff. The biphasic rain garden was designed to increase retention time and removal efficiency of runoff pollutants by creating a sequence of water saturated to unsaturated conditions. We also evaluated the effect of C substrate availability on pollutant removal efficiency in the biphasic rain garden. Five simulated runoff events with various concentrations of runoff pollutants (i.e. nitrate, phosphate, and atrazine) were applied to the monophasic and biphasic rain gardens once every 5d. Hydraulic performance was consistent over the five simulated runoff events. Peak flow was reduced by approximately 56% for the monophasic design and 80% for the biphasic design. Both rain garden systems showed excellent removal efficiency of phosphate (89-100%) and atrazine (84-100%). However, significantly (p<0.001) higher removal of nitrate was observed in the biphasic (42-63%) compared to the monophasic rain garden (29-39%). Addition of C substrate in the form of glucose increased removal efficiency of nitrate significantly (p<0.001), achieving up to 87% removal at a treatment C/N ratio of 2.0. This study demonstrates the importance of retention time, environmental conditions (i.e. saturated/unsaturated conditions), and availability of C substrate for bioremediation of pollutants, especially nitrates, in rain gardens.

  16. Paired associative stimulation targeting the tibialis anterior muscle using either mono or biphasic transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Mrachacz-Kersting, Natalie; Stevenson, Andrew James Thomas

    2017-01-01

    a reduced intensity of this pulse would lead to significant changes as has been reported for hand muscles using a monophasic TMS pulse. Three interventions were investigated: (1) suprathreshold PAbi-PAS (n = 11); (2) suprathreshold PAmono-PAS (n = 11) where PAS was applied using a biphasic or monophasic......Paired associative stimulation (PAS) protocols induce plastic changes within the motor cortex. The objectives of this study were to investigate PAS effects targeting the tibialis anterior (TA) muscle using a biphasic transcranial magnetic stimulation (TMS) pulse form and, to determine whether...

  17. Biphasic decay of the Ca transient results from increased sarcoplasmic reticulum Ca leak

    Science.gov (United States)

    Sankaranarayanan, Rajiv; Li, Yatong; Greensmith, David J.; Eisner, David A.

    2016-01-01

    Key points Ca leak from the sarcoplasmic reticulum through the ryanodine receptor (RyR) reduces the amplitude of the Ca transient and slows its rate of decay.In the presence of β‐adrenergic stimulation, RyR‐mediated Ca leak produces a biphasic decay of the Ca transient with a fast early phase and a slow late phase.Two forms of Ca leak have been studied, Ca‐sensitising (induced by caffeine) and non‐sensitising (induced by ryanodine) and both induce biphasic decay of the Ca transient.Only Ca‐sensitising leak can be reversed by traditional RyR inhibitors such as tetracaine.Ca leak can also induce Ca waves. At low levels of leak, waves occur. As leak is increased, first biphasic decay and then slowed monophasic decay is seen. The level of leak has major effects on the shape of the Ca transient. Abstract In heart failure, a reduction in Ca transient amplitude and contractile dysfunction can by caused by Ca leak through the sarcoplasmic reticulum (SR) Ca channel (ryanodine receptor, RyR) and/or decreased activity of the SR Ca ATPase (SERCA). We have characterised the effects of two forms of Ca leak (Ca‐sensitising and non‐sensitising) on calcium cycling and compared with those of SERCA inhibition. We measured [Ca2+]i with fluo‐3 in voltage‐clamped rat ventricular myocytes. Increasing SR leak with either caffeine (to sensitise the RyR to Ca activation) or ryanodine (non‐sensitising) had similar effects to SERCA inhibition: decreased systolic [Ca2+]i, increased diastolic [Ca2+]i and slowed decay. However, in the presence of isoproterenol, leak produced a biphasic decay of the Ca transient in the majority of cells while SERCA inhibition produced monophasic decay. Tetracaine reversed the effects of caffeine but not of ryanodine. When caffeine (1 mmol l−1) was added to a cell which displayed Ca waves, the wave frequency initially increased before waves disappeared and biphasic decay developed. Eventually (at higher caffeine concentrations), the

  18. Influence of ionizing radiation on nucleus 24 cochlear implants.

    Science.gov (United States)

    Klenzner, T; Knapp, F; Röhner, F; von Wallenberg, E; Mauch, H; Pedersen, P; Aschendorff, A; Laszig, R; Lutterbach, J

    2005-07-01

    To evaluate the influence of conventional or hyperfractionated radiotherapy on Nucleus CI24M or CI24R(CS) implant systems. As a consequence of more than 70,000 cochlear implant recipients worldwide, the potential need for radiotherapy is an issue requiring consideration by both implantees and implantation centers. Conditions requiring radiotherapy of the head may include head, neck, or brain tumors. The study examines the effect of ionizing radiation on cochlear implant function. The implanted devices examined were the Nucleus CI24M and Nucleus CI24R(CS). In a modeled study, two implants of each type were treated with fraction schemes most frequently used in clinical routine (e.g., conventional fractionation [total dose, 120 Gy] and hyperfractionation [total dose, 116 Gy]). Parameters quantified were the implant output amplitude changes at high and low current level (current levels 255 and 100, respectively), the charge balance of the biphasic pulse, and the accuracy of the impedance telemetry function. Within the clinically relevant dose range (< 80 Gy), implant function in all four devices was normal. Failure occurred in one Nucleus CI24R(CS) device treated with hyperfractionation. A dramatic drop in the output amplitude at 106 Gy was observed, and the impedance measurement failed at a total dose of 111 Gy. The results suggest that conventional or hyperfractionated radiotherapy can be applied safely at Nucleus CI24M or CI24R(CS) implant systems in a patient-like setting. Therefore, the authors propose that the results of the study can be applicable in clinical practice.

  19. Cochlear Implant

    Directory of Open Access Journals (Sweden)

    Mehrnaz Karimi

    1992-04-01

    Full Text Available People with profound hearing loss are not able to use some kinds of conventional amplifiers due to the nature of their loss . In these people, hearing sense is stimulated only when the auditory nerve is activated via electrical stimulation. This stimulation is possible through cochlear implant. In fact, for the deaf people who have good mental health and can not use surgical and medical treatment and also can not benefit from air and bone conduction hearing aids, this device is used if they have normal central auditory system. The basic parts of the device included: Microphone, speech processor, transmitter, stimulator and receiver, and electrode array.

  20. Hernia Surgical Mesh Implants

    Science.gov (United States)

    ... Prosthetics Hernia Surgical Mesh Implants Hernia Surgical Mesh Implants Share Tweet Linkedin Pin it More sharing options ... majority of tissue used to produce these mesh implants are from a pig (porcine) or cow (bovine) ...

  1. Urogynecologic Surgical Mesh Implants

    Science.gov (United States)

    ... Prosthetics Urogynecologic Surgical Mesh Implants Urogynecologic Surgical Mesh Implants Share Tweet Linkedin Pin it More sharing options ... majority of tissue used to produce these mesh implants are from a pig (porcine) or cow (bovine). ...

  2. Degradation of implant materials

    CERN Document Server

    Eliaz, Noam

    2012-01-01

    This book surveys the degradation of implant materials, reviewing in detail such failure mechanisms as corrosion, fatigue and wear, along with monitoring techniques. Surveys common implant biomaterials, as well as procedures for implant retrieval and analysis.

  3. Contemporary guided bone regeneration therapy for unaesthetic anterior peri-implantitis case

    Directory of Open Access Journals (Sweden)

    Benso Sulijaya

    2016-12-01

    Full Text Available Background: Dental implant is one of an alternative solutions reconstruction therapy for missing teeth. Complication of dental implant could occurs and leading to implant failure. In order to restore the complication, surgical treatment with guided bone regeneration (GBR is indicated. The potential use of bone substitutes is widely known to be able to regenerate the bone surrounding the implant and maintain bone volume. Purpose: The study aimed to demonstrate the effectiveness of implant-bone fully coverage by using sandwich technique of biphasic calcium phosphate (BCP and demineralized freeze-dried bone allografts (DFDBA bone substitutes combined with collagen resorbable membrane. Case: A 24-year-old male came with diagnosis of peri-implantitis on implant #11. Clinical finding indicated that implant thread was exposed on the labial aspect. Case management: After initial therapy including oral hygiene improvement performed, an operator did a contemporary GBR to correct the defect. Bone graft materials used were 40% β-tri calcium phosphate (β-TCP-60% hydroxyapatite (HA on the outer layer and DFDBA on the inner layer of the defect. Resorbable collagen membrane was used to cover the graft. Conclusion: GBR with sandwich technique could serve as one of the treatment choices for correcting an exposed anterior implant that would enhance the successful aesthetic outcome.

  4. Indirect MR-arthrography in osteochondral autograft and crushed bone graft with a collagen membrane-Correlation with histology

    Energy Technology Data Exchange (ETDEWEB)

    Streitparth, F. [Klinik fuer Strahlenheilkunde, Charite, Campus Virchow-Klinikum, Humboldt-University, Berlin (Germany)], E-mail: florian.streitparth@charite.de; Schoettle, P.; Schell, H. [Center for Musculoskeletal Surgery, Charite, Campus Virchow-Klinikum, Humboldt-University, Berlin (Germany); Lehmkuhl, L.; Madej, T.; Wieners, G. [Klinik fuer Strahlenheilkunde, Charite, Campus Virchow-Klinikum, Humboldt-University, Berlin (Germany); Duda, G.N. [Center for Musculoskeletal Surgery, Charite, Campus Virchow-Klinikum, Humboldt-University, Berlin (Germany); Schroeder, R.J. [Klinik fuer Strahlenheilkunde, Charite, Campus Virchow-Klinikum, Humboldt-University, Berlin (Germany)

    2009-04-15

    Objective: To analyze the spectrum of findings in indirect MR-arthrography following osteochondral autograft transfer system (OATS) and crushed bone graft using a magnetic resonance imaging (MRI) scoring and grading system in relation to histology as the standard of reference. Materials and methods: Iatrogenic lesions were set at ovine condylar facets (n = 6/group), treated with OATS or crushed bone graft. 1.5 T MRI was performed 6 months after surgery using PD-weighted (w fat saturated (fs) fast spin echo (FSE), T1-w 2D, and 3D fs gradient echo (GE) sequences 30 min. after i.v. Gd-DTPA administration and passive joint exercise. The repair tissue was evaluated by two independent radiologists. The MR findings were compared to histology. Results: In all cases, MRI and histologic grading correlated well and showed significant superior repair in OATS at 6 months (p < 0.05), reproducing the original articular contour and a good subchondral restoration. FsT1-w3DGE proved most appropriate identifying characteristic post-operative findings: the OATS group demonstrated bone marrow edema at the donor site and the graft/host interface showed significant enhancement in indirect MR-arthrography, indicating fibrocartilage. After crushed bone graft, we found an irregular structure and significant contrast uptake, consistent with remnants of bone grafts surrounded by inflammatory tissue. Conclusion: Indirect MR-arthrography is an accurate, non-invasive monitoring tool following OATS and crushed bone graft as the MRI scoring and grading system allows a reliable evaluation of normal and pathological osteochondral repair with a high histologic correlation.

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

    Directory of Open Access Journals (Sweden)

    CJ Ley

    2014-03-01

    Full Text Available 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.

  6. 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.

  7. Complications after cardiac implantable electronic device implantations

    DEFF Research Database (Denmark)

    Kirkfeldt, Rikke Esberg; Johansen, Jens Brock; Nohr, Ellen Aagaard;

    2014-01-01

    Complications after cardiac implantable electronic device (CIED) treatment, including permanent pacemakers (PMs), cardiac resynchronization therapy devices with defibrillators (CRT-Ds) or without (CRT-Ps), and implantable cardioverter defibrillators (ICDs), are associated with increased patient...

  8. Implant marketing: cost effective implant dentistry.

    Science.gov (United States)

    Wohrle, P S; Levin, R P

    1996-01-01

    The application of the KAL-Technique to the field of implant dentistry allows both patients and dental practices to benefit. It is an exciting advance that decreases frustration and stress in providing implant procedures and lowers overall costs. Professionals using the KAL-Technique report significant predictability in achieving passive framework fit. They are also lowering overall cost of implant cases, which increases the number of patients who can accept implant treatment. It has been well established that the more individuals in a practice that receive implants, the more referrals a practice will gain. This is because implant patients find tremendous advances in the quality of life, and do not hesitate to tell others who can take advantage of this opportunity. Implant dentistry is one of the fastest growing fields in dentistry today. While some other areas of dentistry begin to decline in volume and need, implant dentistry provides the opportunity to keep practices strong and to insure long-term success.

  9. Biphasic Catalytic(Hydroformylation of 1-Dodecene in Micellar System with Cationic Gemini Surfactants

    Institute of Scientific and Technical Information of China (English)

    Min LI; Bin XU; Hua CHEN; Hong Jie ZHENG; Xue Yuan HUANG; Yao Zhong LI; Xian Jun LI

    2004-01-01

    The promotion effect of cationic gemini surfactants for the hydroformylation of 1-dodecene in the organic/aqueous biphasic catalytic system is reported. The hydroformylation reaction in the presence of gemini surfactant occurred with higher turnover frequency and higher selectivity for linear aldehyde than using conventional monomeric surfactant CTAB.

  10. Modeling Biphasic Environmental Decay of Pathogens and Implications for Risk Analysis.

    Science.gov (United States)

    Brouwer, Andrew F; Eisenberg, Marisa C; Remais, Justin V; Collender, Philip A; Meza, Rafael; Eisenberg, Joseph N S

    2017-02-21

    As the appreciation for the importance of the environment in infectious disease transmission has grown, so too has interest in pathogen fate and transport. Fate has been traditionally described by simple exponential decay, but there is increasing recognition that some pathogens demonstrate a biphasic pattern of decay-fast followed by slow. While many have attributed this behavior to population heterogeneity, we demonstrate that biphasic dynamics can arise through a number of plausible mechanisms. We examine the identifiability of a general model encompassing three such mechanisms: population heterogeneity, hardening off, and the existence of viable-but-not-culturable states. Although the models are not fully identifiable from longitudinal sampling studies of pathogen concentrations, we use a differential algebra approach to determine identifiable parameter combinations. Through case studies using Cryptosporidium and Escherichia coli, we show that failure to consider biphasic pathogen dynamics can lead to substantial under- or overestimation of disease risks and pathogen concentrations, depending on the context. More reliable models for environmental hazards and human health risks are possible with an improved understanding of the conditions in which biphasic die-off is expected. Understanding the mechanisms of pathogen decay will ultimately enhance our control efforts to mitigate exposure to environmental contamination.

  11. A New Type of Biphasic Calcium Phosphate Cement as a Gentamicin Carrier for Osteomyelitis

    Directory of Open Access Journals (Sweden)

    Wen-Yu Su

    2013-01-01

    Full Text Available Osteomyelitis therapy is a long-term and inconvenient procedure for a patient. Antibiotic-loaded bone cements are both a complementary and alternative treatment option to intravenous antibiotic therapy for the treatment of osteomyelitis. In the current study, the biphasic calcium phosphate cement (CPC, called α-TCP/HAP (α-tricalcium phosphate/hydroxyapatite biphasic cement, was prepared as an antibiotics carrier for osteomyelitis. The developed biphasic cement with a microstructure of α-TCP surrounding the HAP has a fast setting time which will fulfill the clinical demand. The X-ray diffraction and Fourier transform infrared spectrometry analyses showed the final phase to be HAP, the basic bone mineral, after setting for a period of time. Scanning electron microscopy revealed a porous structure with particle sizes of a few micrometers. The addition of gentamicin in α-TCP/HAP would delay the transition of α-TCP but would not change the final-phase HAP. The gentamicin-loaded α-TCP/HAP supplies high doses of the antibiotic during the initial 24 hours when they are soaked in phosphate buffer solution (PBS. Thereafter, a slower drug release is produced, supplying minimum inhibitory concentration until the end of the experiment (30 days. Studies of growth inhibition of Staphylococcus aureus and Pseudomonas aeruginosa in culture indicated that gentamicin released after 30 days from α-TCP/HAP biphasic cement retained antibacterial activity.

  12. Biphasic Electrical Field Stimulation Aids in Tissue Engineering of Multicell-Type Cardiac Organoids

    Science.gov (United States)

    Chiu, Loraine L.Y.; Iyer, Rohin K.; King, John-Paul

    2011-01-01

    The main objectives of current work were (1) to compare the effects of monophasic or biphasic electrical field stimulation on structure and function of engineered cardiac organoids based on enriched cardiomyocytes (CM) and (2) to determine if electrical field stimulation will enhance electrical excitability of cardiac organoids based on multiple cell types. Organoids resembling cardiac myofibers were cultivated in Matrigel-coated microchannels fabricated of poly(ethylene glycol)-diacrylate. We found that field stimulation using symmetric biphasic square pulses at 2.5 V/cm, 1 Hz, 1 ms (per pulse phase) was an improved stimulation protocol, as compared to no stimulation and stimulation using monophasic square pulses of identical total amplitude and duration (5 V/cm, 1 Hz, 2 ms). This was supported by the highest success rate for synchronous contractions, low excitation threshold, the highest cell density, and the highest expression of Connexin-43 in the biphasic group. Subsequently, enriched CM were seeded on the networks of (1) cardiac fibroblasts (FB), (2) D4T endothelial cells (EC), or (3) a mixture of FB and EC that were precultured for 2 days prior to the addition of enriched CM. Biphasic field stimulation was also effective at improving electrical excitability of these cardiac organoids by improving the three-dimensional organization of the cells, increasing cellular elongation and enhancing Connexin-43 presence. PMID:18783322

  13. Biphasic electrical field stimulation aids in tissue engineering of multicell-type cardiac organoids.

    Science.gov (United States)

    Chiu, Loraine L Y; Iyer, Rohin K; King, John-Paul; Radisic, Milica

    2011-06-01

    The main objectives of current work were (1) to compare the effects of monophasic or biphasic electrical field stimulation on structure and function of engineered cardiac organoids based on enriched cardiomyocytes (CM) and (2) to determine if electrical field stimulation will enhance electrical excitability of cardiac organoids based on multiple cell types. Organoids resembling cardiac myofibers were cultivated in Matrigel-coated microchannels fabricated of poly(ethylene glycol)-diacrylate. We found that field stimulation using symmetric biphasic square pulses at 2.5 V/cm, 1 Hz, 1 ms (per pulse phase) was an improved stimulation protocol, as compared to no stimulation and stimulation using monophasic square pulses of identical total amplitude and duration (5 V/cm, 1 Hz, 2 ms). This was supported by the highest success rate for synchronous contractions, low excitation threshold, the highest cell density, and the highest expression of Connexin-43 in the biphasic group. Subsequently, enriched CM were seeded on the networks of (1) cardiac fibroblasts (FB), (2) D4T endothelial cells (EC), or (3) a mixture of FB and EC that were precultured for 2 days prior to the addition of enriched CM. Biphasic field stimulation was also effective at improving electrical excitability of these cardiac organoids by improving the three-dimensional organization of the cells, increasing cellular elongation and enhancing Connexin-43 presence.

  14. Calculation of the valence electron structures of alloying cementite and its biphase interface

    Institute of Scientific and Technical Information of China (English)

    刘志林; 李志林; 刘伟东

    2001-01-01

    The valence electron structures of alloying cementite θ-(Fe, M)3C and ε-(Fe, M)3C andthose of the biphase interfaces between them and α-Fe are calculated with Yu's empirical electrontheory of solid and molecules. The calculation results accord with the actual behavior of alloys.

  15. Intracellular lactate-mediated induction of estrogen receptor beta (ERβ) in biphasic malignant pleural mesothelioma cells.

    Science.gov (United States)

    Manente, Arcangela G; Pinton, Giulia; Zonca, Sara; Cilli, Michele; Rinaldi, Maurizio; Daga, Antonio; Nilsson, Stefan; Moro, Laura

    2015-09-22

    Biphasic malignant pleural mesothelioma (MPM) is the second most common histotype of MPM. It is histologically characterized by the concomitant presence of epithelioid and sarcomatoid features, the latter associated with worse prognosis. In this report we describe that silencing of AKT1 in spindle-shaped biphasic MPM cells promotes the shift toward an epithelioid phenotype. Furthermore, AKT1 silencing resulted in decreased expression of the lactate/H+ symporter MCT4 and its chaperone CD147/Basigin, and in the induction of estrogen receptor β (ERβ) expression. We provide evidence that ERβ expression is induced by increased intracellular lactate concentration. Spheroid culturing and tumor growth of ERβ negative biphasic MPM in nude mice resulted in the induction of ERβ expression and response to the selective agonist KB9520. In both models, the treatment with the ERβ agonist results in reduced cell proliferation, decreased expression of MCT4 and CD147/Basigin and increased acetylation and inactivation of AKT1. Collectively, in response to metabolic changes, ERβ expression is induced and exerts an anti-tumor effect through selective agonist activation. The possibility to reverse the more aggressive biphasic mesothelioma histotype by targeting ERβ with a selective agonist could represent a new effective treatment strategy.

  16. Phase Behaviors in Bi-phase Simulation of Powder Segregation in Metal Injection Molding

    Institute of Scientific and Technical Information of China (English)

    Liu Baosheng; Fan Xiaoxin; Cheng Zhiqiang

    2006-01-01

    Powder segregation induced by mold filling is an important phenomenon that affects the final quality of metal injection molding (MIM). The prediction of segregation in MIM requires a bi-phase flow model to describe distinctly the flows of metallic powder and polymer binder. Viscous behaviors for the flows of each phase should hence be determined. The coefficient of interaction between the flows of two phases should also be evaluated. However, only viscosity of the mixed feedstock is measurable by capillary tests. Wall sticking is supposed in the traditional model for capillary tests, while the wall slip is important to be taken into account in MIM injection. Objective of the present paper is to introduce the slip effect in bi-phase simulation, and search the suitable way to determine the viscous behaviors for each phase with the consideration of wall slip in capillary tests. Analytical and numerical methods were proposed to realize such a specific purpose. The proposed method is based on the mass conservation between the capillary flows in mono-phase model for the mixed feedstock and in bi-phase model for the flows of two phases. Examples of the bi-phase simulation in MIM were realized with the software developed by research team. The results show evident segregation, which is valuable for improving the mould designs.

  17. Engineering anisotropic biphasic Janus-type polymer nanofiber scaffold networks via centrifugal jet spinning.

    Science.gov (United States)

    Khang, Alex; Ravishankar, Prashanth; Krishnaswamy, Aditya; Anderson, Patrick K; Cone, Stephanie G; Liu, Zizhao; Qian, Xianghong; Balachandran, Kartik

    2017-11-01

    Biphasic materials, comprised of an ordered arrangement of two different material phases within a material, have the potential for a wide variety of applications including filtration, protective clothing and tissue engineering. This study reports for the first time, a process for engineering biphasic Janus-type polymeric nanofiber (BJPNF) networks via the centrifugal jet spinning technique. BJPNF alignment and fiber diameter was dependent on fabrication rotational speed as well as solution composition. The biphasic character of these BJPNFs, which was controlled via the rotational speed of fabrication, was confirmed at the individual nanofiber scale using energy dispersive X-ray spectroscopy, and at the bulk, macro-scale using attenuated total reflectance-Fourier transform infrared spectroscopy. Biphasic character was also demonstrated at the functional level via differing affinities on either side of the BJPNF for cell attachment. Our work thus presents a method for fabricating BJPNF scaffold networks where there might be a need for different properties on either side of a material. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2455-2464, 2017. © 2016 Wiley Periodicals, Inc.

  18. Paired associative stimulation targeting the tibialis anterior muscle using either mono or biphasic transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Mrachacz-Kersting, Natalie; Stevenson, Andrew James Thomas

    2017-01-01

    Paired associative stimulation (PAS) protocols induce plastic changes within the motor cortex. The objectives of this study were to investigate PAS effects targeting the tibialis anterior (TA) muscle using a biphasic transcranial magnetic stimulation (TMS) pulse form and, to determine whether...

  19. CHRONIC ALCOHOL CONSUMPTION HAS BIPHASIC EFFECTS ON HEPATIC INSULIN SIGNALING DEPENDENT ON DOSE

    Science.gov (United States)

    Epidemiological studies have shown paradoxical biphasic effects of alcohol on health. Moderate drinkers have lower overall mortality than teetotalers or than heavy drinkers. There are protective effects of low levels of alcohol consumption (less than one drink day) on diabetes risk and other chroni...

  20. Cumulative Incidence of Osteochondritis Dissecans of the Capitellum in Child and Adolescent Baseball Players

    Science.gov (United States)

    Iwame, Toshiyuki; Matsuura, Tetsuya; Suzue, Naoto; Sairyo, Koichi

    2016-01-01

    Objectives: Prevalence of osteochondritis dissecans (OCD) of the capitellum is high among individuals who have played baseball since childhood. Recently two cross-sectional studies according to prevalence of OCD have been published. In a study of 1040 baseball players aged 10 to 12 years, Matsuura et al found that 2.1% of players had OCD, with no differences in prevalence according to age or player position. Kida et al., in their study of 2433 baseball players aged 12 to 18 years, found OCD in 3.4% of subjects. Furthermore, they found that players with OCD began playing baseball at earlier ages, had played for longer periods, and had experienced more elbow pain. The player’s current baseball position may not be related to the existence of OCD lesions. Together, these findings led us to examine the longitudinal study for examining the risk factors for occurrence of OCD. Our objectives were to determine (1) cumulative incidence rates of OCD in the school child players aged 6-11 years old, (2) the relative risk of OCD by age, beginning age playing baseball, playing period, experimental hours per week, playing position, and elbow pain. Methods: A total of 1,275 players aged 6-11 years (mean, 9.4 years) belonged to youth baseball teams without OCD lesions received examination in the next year and were the subjects of this investigation. Subjects were examined by questionnaire, and ultrasonographic and radiographic examination. Questionnaire items included age, player position, beginning age of playing baseball, playing period of baseball, number of training hours per week and history of elbow pain. Ultrasonography of the lateral aspect of the elbow was performed. An irregularity of the subchondral bone of the capitellum was regarded as an abnormality. Radiographic examination was recommended to players who had an abnormal finding on ultrasonographic examination. We investigated the following risk factors for occurrence of OCD: age, player position, beginning age of

  1. Custom-Made Computer-Aided-Design/Computer-Aided-Manufacturing Biphasic Calcium-Phosphate Scaffold for Augmentation of an Atrophic Mandibular Anterior Ridge

    Directory of Open Access Journals (Sweden)

    Francesco Guido Mangano

    2015-01-01

    Full Text Available This report documents the clinical, radiographic, and histologic outcome of a custom-made computer-aided-design/computer-aided-manufactured (CAD/CAM scaffold used for the alveolar ridge augmentation of a severely atrophic anterior mandible. Computed tomographic (CT images of an atrophic anterior mandible were acquired and modified into a 3-dimensional (3D reconstruction model; this was transferred to a CAD program, where a custom-made scaffold was designed. CAM software generated a set of tool-paths for the manufacture of the scaffold on a computer-numerical-control milling machine into the exact shape of the 3D design. A custom-made scaffold was milled from a synthetic micromacroporous biphasic calcium phosphate (BCP block. The scaffold closely matched the shape of the defect: this helped to reduce the time for the surgery and contributed to good healing. One year later, newly formed and well-integrated bone was clinically available, and two implants (AnyRidge, MegaGen, Gyeongbuk, South Korea were placed. The histologic samples retrieved from the implant sites revealed compact mature bone undergoing remodelling, marrow spaces, and newly formed trabecular bone surrounded by residual BCP particles. This study demonstrates that custom-made scaffolds can be fabricated by combining CT scans and CAD/CAM techniques. Further studies on a larger sample of patients are needed to confirm these results.

  2. Porous biphasic calcium phosphate ceramics coated with nano-hydroxyapatite and seeded with mesenchymal stem cells for reconstruction of radius segmental defects in rabbits.

    Science.gov (United States)

    Hu, Jianzhong; Yang, Zhiming; Zhou, Yongchun; Liu, Yong; Li, Kaiyang; Lu, Hongbin

    2015-11-01

    The osteoconduction of porous biphasic calcium phosphate (BCP) ceramics has been widely reported. In a previous study, we demonstrated that applying a nano-hydroxyapatite (nHA) coating enhances the osteoinductive potential of BCP ceramics, making these scaffolds more suitable for bone tissue engineering applications. The aim of the present study was to determine the effects of reconstructing radius defects in rabbits using nHA-coated BCP ceramics seeded with mesenchymal stem cells (MSCs) and to compare the bone regeneration induced by different scaffolds. Radius defects were created in 20 New Zealand rabbits, which were divided into four groups by treatment: porous BCP ceramics (Group A), nHA-coated porous BCP ceramics (Group B), porous BCP ceramics seeded with rabbit MSCs (Group C), and nHA-coated porous BCP ceramics seeded with rabbit MSCs (Group D). After in vitro incubation, the cell/scaffold complexes were implanted into the defects. Twelve weeks after implantation, the specimens were examined macroscopically and histologically. Both the nHA coating and seeding with MSCs enhanced the formation of new bone tissue in the BCP ceramics, though the osteoinductive potential of the scaffolds with MSCs was greater than that of the nHA-coated scaffolds. Notably, the combination of nHA coating and MSCs significantly improved the bone regeneration capability of the BCP ceramics. Thus, MSCs seeded into porous BCP ceramics coated with nHA may be an effective bone substitute to reconstruct bone defects in the clinic.

  3. Phase conversion of tricalcium phosphate into Ca-deficient apatite during sintering of hydroxyapatite-tricalcium phosphate biphasic ceramics.

    Science.gov (United States)

    Kong, Young-Min; Kim, Hyoun-Ee; Kim, Hae-Won

    2008-02-01

    In this study, we report a new observation on the phase conversion that occurs during the sintering of hydroxyapatite (HA)-tricalcium phosphate (TCP) biphasic ceramics. During the sintering of the HA-TCP mixture powders, a large amount of TCP was converted into HA, as detected by X-ray diffraction. The amount of TCP transformed into HA was approximately 10-90% of that initially added. From the electron probe microscopy analysis, the HA transformed from TCP was found to be Ca-deficient with Ca/P ratios of 1.62-1.64. The dissolution behavior and osteoblastic responses in a series of HA-TCP biphasic ceramics (10-90% TCP) were assessed. The solubility of the HA-TCP biphasic ceramics was intermediate between that of the HA and TCP pure ceramics. However, in the case of the HA-90% TCP biphasic ceramic, the solubility was even higher than that of pure TCP. The cell proliferation and alkaline phosphatase activity of the cells on the biphasic ceramics were lower than those on pure HA, but higher than those on pure TCP. However, particularly in the HA-50% TCP biphasic composition, the cellular responses were significantly higher than those on pure HA. It is considered that the Ca-deficient apatite newly formed from the TCP may affect in some way the solubility and biological properties of the HA-TCP biphasic ceramics.

  4. Induction of bone formation in biphasic calcium phosphate scaffolds by bone morphogenetic protein-2 and primary osteoblasts.

    Science.gov (United States)

    Strobel, L A; Rath, S N; Maier, A K; Beier, J P; Arkudas, A; Greil, P; Horch, R E; Kneser, U

    2014-03-01

    Bone tissue engineering strategies mainly depend on porous scaffold materials. In this study, novel biphasic calcium phosphate (BCP) matrices were generated by 3D-printing. High porosity was achieved by starch consolidation. This study aimed to characterise the porous BCP-scaffold properties and interactions of osteogenic cells and growth factors under in vivo conditions. Five differently treated constructs were implanted subcutaneously in syngeneic rats: plain BCP constructs (group A), constructs pre-treated with BMP-2 (group B; 1.6 µg BMP-2 per scaffold), seeded with primary osteoblasts (OB) (group C), seeded with OB and BMP-2 (group D) and constructs seeded with OB and pre-cultivated in a flow bioreactor for 6 weeks (group E). After 2, 4 and 6 weeks, specimens were explanted and subjected to histological and molecular biological analyses. Explanted scaffolds were invaded by fibrovascular tissue without significant foreign body reactions. Morphometric analysis demonstrated significantly increased bone formation in samples from group D (OB + BMP-2) compared to all other groups. Samples from groups B-E displayed significant mRNA expression of bone-specific genes after 6 weeks. Pre-cultivation in the flow bioreactor (group E) induced bone formation comparable with group B. In this study, differences in bone distribution between samples with BMP-2 or osteoblasts could be observed. In conclusion, combination of osteoblasts and BMP-2 synergistically enhanced bone formation in novel ceramic scaffolds. These results provide the basis for further experiments in orthotopic defect models with a focus on future applications in orthopaedic and reconstructive surgery.

  5. 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.

  6. 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.

  7. Retrograde peri-implantitis

    Directory of Open Access Journals (Sweden)

    Mohamed Jumshad

    2010-01-01

    Full Text Available Retrograde peri-implantitis constitutes an important cause for implant failure. Retrograde peri-implantitis may sometimes prove difficult to identify and hence institution of early treatment may not be possible. This paper presents a report of four cases of (the implant placed developing to retrograde peri-implantitis. Three of these implants were successfully restored to their fully functional state while one was lost due to extensive damage. The paper highlights the importance of recognizing the etiopathogenic mechanisms, preoperative assessment, and a strong postoperative maintenance protocol to avoid retrograde peri-implant inflammation.

  8. [Bilateral cochlear implantation].

    Science.gov (United States)

    Kronenberg, Jona; Migirov, Lela; Taitelbaum-Swead, Rikey; Hildesheimer, Minka

    2010-06-01

    Cochlear implant surgery became the standard of care in hearing rehabilitation of patients with severe to profound sensorineural hearing loss. This procedure may alter the lives of children and adults enabling them to integrate with the hearing population. In the past, implantation was performed only in one ear, despite the fact that binaural hearing is superior to unilateral, especially in noisy conditions. Cochlear implantation may be performed sequentially or simultaneously. The "sensitive period" of time between hearing loss and implantation and between the two implantations, when performed sequentially, significantly influences the results. Shorter time spans between implantations improve the hearing results after implantation. Hearing success after implantation is highly dependent on the rehabilitation process which includes mapping, implant adjustments and hearing training. Bilateral cochlear implantation in children is recommended as the proposed procedure in spite of the additional financial burden.

  9. Water/Oil Biphasic Hydroformylation of Higher Olefins over a TPPTS-Rh/SiO2 Catalyst

    Institute of Scientific and Technical Information of China (English)

    Hejun Zhu; Yunjie Ding; Fu Yang; Li Yan; Jianmin Xiong; Hongmei Yin; Liwu Lin

    2004-01-01

    A novel TPPTS-Rh/SiO2 catalyst, prepared by directly modifying a heterogeneous highsurface-area Rh/SiO2 catalyst with water-soluble TPPTS ligands, could decrease the resistance of mass transfer in water/oil biphasic media for the hydroformylation of higher olefins. The catalytic performance for hydroformylation on this biphasic TPPTS-Rh/SiO2 catalyst system was higher than those of the traditional biphasic HRhCO(TPPTS)3 systems, owing to the chemical bonds between the highly dispersed Rh metal particles and the TPPTS ligands. The catalyst system is applicable for hydroformylation of higher olefins such as 1-dodecene.

  10. Efficacy and safety of biphasic insulin aspart and biphasic insulin lispro mix in patients with type 2 diabetes: A review of the literature

    Directory of Open Access Journals (Sweden)

    Ajay Kumar

    2016-01-01

    Full Text Available Type 2 diabetes (T2D represents an escalating burden worldwide, particularly in China and India. Compared with Caucasians, Asian people with diabetes have lower body mass index, increased visceral adiposity, and postprandial glucose (PPG/insulin resistance. Since postprandial hyperglycemia contributes significantly to total glycemic burden and is associated with heightened cardiovascular risk, targeting PPG early in T2D is paramount. Premixed insulin regimens are widely used in Asia due to their convenience and effectiveness. Data from randomized controlled trials and observational studies comparing efficacy and safety of biphasic insulin aspart 30 (BIAsp 30 with biphasic insulin lispro mix (LM 25/50 and versus other insulin therapies or oral antidiabetic drugs (OADs in T2D demonstrated that BIAsp 30 and LM 25/50 were associated with similar or greater improvements in glycemic control versus comparator regimens, such as basal–bolus insulin, in insulin-naÏve, and prior insulin users. Studies directly comparing BIAsp 30 and LM 25 provided conflicting glycemic control results. Safety data generally showed increased hypoglycemia and weight gain with premixed insulins versus basal–bolus insulin or OADs. However, large observational trials documented improvements in glycated hemoglobin, PPG, and hypoglycemia with BIAsp 30 in multi-ethnic patient populations. In summary, this literature review demonstrates that premixed insulin regimens are an appropriate and effective treatment choice in T2D.

  11. Biphasic and boundary lubrication mechanisms in artificial hydrogel cartilage: A review.

    Science.gov (United States)

    Murakami, Teruo; Yarimitsu, Seido; Nakashima, Kazuhiro; Sakai, Nobuo; Yamaguchi, Tetsuo; Sawae, Yoshinori; Suzuki, Atsushi

    2015-12-01

    Various studies on the application of artificial hydrogel cartilage to cartilage substitutes and artificial joints have been conducted. It is expected in clinical application of artificial hydrogel cartilage that not only soft-elastohydrodynamic lubrication but biphasic, hydration, gel-film and boundary lubrication mechanisms will be effective to sustain extremely low friction and minimal wear in daily activities similar to healthy natural synovial joints with adaptive multimode lubrication. In this review article, the effectiveness of biphasic lubrication and boundary lubrication in hydrogels in thin film condition is focused in relation to the structures and properties of hydrogels. As examples, the tribological behaviors in three kinds of poly(vinyl alcohol) hydrogels with high water content are compared, and the importance of lubrication mechanism in biomimetic artificial hydrogel cartilage is discussed to extend the durability of cartilage substitute.

  12. Biphasic catalysis using amphiphilic polyphenols-chelated noble metals as highly active and selective catalysts

    Science.gov (United States)

    Mao, Hui; Yu, Hong; Chen, Jing; Liao, Xuepin

    2013-07-01

    In the field of catalysis, it is highly desired to develop novel catalysts that combine the advantages of both homogeneous and heterogeneous catalysts. Here we disclose that the use of plant pholyphenol as amphiphilic large molecule ligand/stabilizer allows for the preparation of noble metal complex and noble metal nanoparticle catalysts. These catalysts are found to be highly selective and active in aqueous-organic biphasic catalysis of cinnamaldehyde and quinoline, and can be reused at least 3 times without significant loss of activity. Moreover, the catalytic activity and reusability of the catalysts can be rationally controlled by simply adjusting the content of polyphenols in the catalysts. Our strategy may be extended to design a wide range of aqueous-organic biphasic catalysis system.

  13. A method for separating water soluble organics from a process stream by aqueous biphasic extraction

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, David J.; Mego, William A.

    1997-12-01

    The present invention relates to a method for separating water-miscible organic species from a process stream by aqueous biphasic extraction. In particular, the method includes extracting the organic species into a polymer-rich phase of an aqueous biphase system in which the process stream comprises the salt-rich phase, and, next, separating the polymer from the extracted organic species by contacting the loaded, polymer-rich phase with a water-immiscible organic phase. Alternatively, the polymer can be separated from the extracted organic species by raising the temperature of the loaded, polymer-rich phase above the cloud point, such that the polymer and the water-soluble organic species separate into two distinct aqueous phases. In either case, a substantially salt-free, concentrated aqueous solution containing the organic species is recovered.

  14. A biphasic hyperelastic model for the analysis of fluid and mass transport in brain tissue.

    Science.gov (United States)

    García, José Jaime; Smith, Joshua H

    2009-02-01

    A biphasic hyperelastic finite element model is proposed for the description of the mechanical behavior of brain tissue. The model takes into account finite deformations through an Ogden-type hyperelastic compressible function and a hydraulic conductivity dependent on deformation. The biphasic equations, implemented here for spherical symmetry using an updated Lagrangian algorithm, yielded radial coordinates and fluid velocities that were used with the convective-diffusive equation in order to predict mass transport in the brain. Results of the model were equal to those of a closed-form solution under infinitesimal deformations, however, for a wide range of material parameters, the model predicted important increments in the infusion sphere, reductions of the fluid velocities, and changes in the species content distribution. In addition, high localized deformation and stresses were obtained at the infusion sphere. Differences with the infinitesimal solution may be mainly attributed to geometrical nonlinearities related to the increment of the infusion sphere and not to material nonlinearities.

  15. 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

  16. Nitric oxide interacts with salicylate to regulate biphasic ethylene production during the hypersensitive response.

    Science.gov (United States)

    Mur, Luis A J; Laarhoven, Lucas J J; Harren, Frans J M; Hall, Michael A; Smith, Aileen R

    2008-11-01

    C(2)H(4) is associated with plant defense, but its role during the hypersensitive response (HR) remains largely uncharacterized. C(2)H(4) production in tobacco (Nicotiana tabacum) following inoculation with HR-eliciting Pseudomonas syringae pathovars measured by laser photoacoustic detection was biphasic. A first transient rise (C(2)H(4)-I) occurred 1 to 4 h following inoculation with HR-eliciting, disease-forming, and nonpathogenic strains and also with flagellin (flg22). A second (avirulence-dependent) rise, at approximately 6 h (C(2)H(4)-II), was only seen with HR-eliciting strains. Tobacco leaves treated with the C(2)H(4) biosynthesis inhibitor, aminoethoxyvinylglycine, suggested that C(2)H(4) influenced the kinetics of a HR. Challenging salicylate hydroxylase-expressing tobacco lines and tissues exhibiting systemic acquired resistance suggested that C(2)H(4) production was influenced by salicylic acid (SA). Disrupted expression of a C(2)H(4) biosynthesis gene in salicylate hydroxylase tobacco plants implicated transcriptional control as a mechanism through which SA regulates C(2)H(4) production. Treating leaves to increase oxidative stress or injecting with SA initiated monophasic C(2)H(4) generation, but the nitric oxide (NO) donor sodium nitroprusside initiated biphasic rises. To test whether NO influenced biphasic C(2)H(4) production during the HR, the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester was coinoculated with the avirulent strain of P. syringae pv phaseolicola into tobacco leaves. The first transient C(2)H(4) rise appeared to be unaffected by N(G)-nitro-L-arginine methyl ester, but the second rise was reduced. These data suggest that NO and SA are required to generate the biphasic pattern of C(2)H(4) production during the HR and may influence the kinetics of HR formation.

  17. A simulation study of the reaction of human heart to biphasic electrical shocks

    Directory of Open Access Journals (Sweden)

    Seemann Gunnar

    2004-06-01

    Full Text Available Abstract Background This article presents a study, which examines the effects of biphasic electrical shocks on human ventricular tissue. The effects of this type of shock are not yet fully understood. Animal experiments showed the superiority of biphasic shocks over monophasic ones in defibrillation. A mathematical computer simulation can increase the knowledge of human heart behavior. Methods The research presented in this article was done with different models representing a three-dimensional wedge of ventricular myocardium. The electrophysiology was described with Priebe-Beuckelmann model. The realistic fiber twist, which is specific to human myocardium was included. Planar electrodes were placed at the ends of the longest side of the virtual cardiac wedge, in a bath medium. They were sources of electrical shocks, which varied in magnitude from 0.1 to 5 V. In a second arrangement ring electrodes were placed directly on myocardium for getting a better view on secondary electrical sources. The electrical reaction of the tissue was generated with a bidomain model. Results The reaction of the tissue to the electrical shock was specific to the initial imposed characteristics. Depolarization appeared in the first 5 ms in different locations. A further study of the cardiac tissue behavior revealed, which features influence the response of the considered muscle. It was shown that the time needed by the tissue to be totally depolarized is much shorter when a biphasic shock is applied. Each simulation ended only after complete repolarization was achieved. This created the possibility of gathering information from all states corresponding to one cycle of the cardiac rhythm. Conclusions The differences between the reaction of the homogeneous tissue and a tissue, which contains cleavage planes, reveals important aspects of superiority of biphasic pulses. ...

  18. A Phenomenological Model of the Electrically Stimulated Auditory Nerve Fiber: Temporal and Biphasic Response Properties.

    Science.gov (United States)

    Horne, Colin D F; Sumner, Christian J; Seeber, Bernhard U

    2016-01-01

    We present a phenomenological model of electrically stimulated auditory nerve fibers (ANFs). The model reproduces the probabilistic and temporal properties of the ANF response to both monophasic and biphasic stimuli, in isolation. The main contribution of the model lies in its ability to reproduce statistics of the ANF response (mean latency, jitter, and firing probability) under both monophasic and cathodic-anodic biphasic stimulation, without changing the model's parameters. The response statistics of the model depend on stimulus level and duration of the stimulating pulse, reproducing trends observed in the ANF. In the case of biphasic stimulation, the model reproduces the effects of pseudomonophasic pulse shapes and also the dependence on the interphase gap (IPG) of the stimulus pulse, an effect that is quantitatively reproduced. The model is fitted to ANF data using a procedure that uniquely determines each model parameter. It is thus possible to rapidly parameterize a large population of neurons to reproduce a given set of response statistic distributions. Our work extends the stochastic leaky integrate and fire (SLIF) neuron, a well-studied phenomenological model of the electrically stimulated neuron. We extend the SLIF neuron so as to produce a realistic latency distribution by delaying the moment of spiking. During this delay, spiking may be abolished by anodic current. By this means, the probability of the model neuron responding to a stimulus is reduced when a trailing phase of opposite polarity is introduced. By introducing a minimum wait period that must elapse before a spike may be emitted, the model is able to reproduce the differences in the threshold level observed in the ANF for monophasic and biphasic stimuli. Thus, the ANF response to a large variety of pulse shapes are reproduced correctly by this model.

  19. Biphasic and SAPC Hydroformylation Catalyzed by Rh-phosphines Bound to Water-Soluble Polymers

    DEFF Research Database (Denmark)

    Malmstrøm, Torsten; Andersson, Carlaxel; Hjortkjær, Jes

    1999-01-01

    Coupling of the triphenylphosphine moiety to poly-acrylic acid and poly-ethyleneimine respectively afford the macromolecular ligands PAA-PNH and PEI-PNH. Reaction of the ligands with Rh(CO)2(acac) give water-soluble complexes that are active as catalysts in the hydroformylation ofdifferent olefin...... PEI-PNH as ligands show lower stability and activity in both SAPC and biphasic applications....

  20. The Polyacetylenes Falcarinol and Falcarindiol Affect Stress Responses in Myotube Cultures in a Biphasic Manner

    OpenAIRE

    Young, Jette F; Christensen, Lars P.; Theil, Peter K.; Oksbjerg, Niels

    2008-01-01

    The effects of the bioactive polyacetylenes, falcarinol and falcarindiol, present in carrots, celery, celeriac and other umbelliferous vegetables, on the stress responses in primary myotube cultures, were studied. Biphasic responses on cellular stress responses in myotube cultures were investigated by exposing them to various concentrations of falcarinol and falcarindiol for 24 h before testing effects of 100 μM H2O2 on the intracellular formation of reactive oxygen species (ROS), transcripti...

  1. 4-Hydroxy-2-nonenal induces endothelial cell injury via PKCdelta and biphasic JNK activation

    OpenAIRE

    Goya, Sho; Hirata, Haruhiko; Hoshino, Shigenori; Inoue, Koji; Kashiwa, Yozo; Kawase, Ichiro; Kijima, Takashi; Kumagai, Toru; Mayumi, Masahiko; Osaki, Tadashi; Suzuki, Mayumi; Tachibana, Isao; Takeda, Yoshito; Takimoto, Takayuki; Yano, Yukihiro

    2008-01-01

    4-Hydroxy-2-nonenal (4-HNE), a major product generated during oxidative stress, exhibits cytotoxic effects; however, the mechanisms of 4-HNE-induced endothelial cell injury are not well defined. To explore this issue, we examined how 4-HNE damages human umbilical vein endothelial cells (HUVECs) and found that 4-HNE induced biphasic activation of c-Jun N-terminal kinase (JNK). Both pre- and post-treatment of HUVECs with SP600125, a specific JNK inhibitor, significantly suppresse...

  2. Dehydration of xylose to furfural over niobium phosphate catalyst in biphasic solvent system

    Institute of Scientific and Technical Information of China (English)

    Boonrat; Pholjaroen; Ning; Li; Zhiqiang; Wang; Aiqin; Wang; Tao; Zhang

    2013-01-01

    Phosphoric acid treated niobic acid(NbP)was used for the dehydration of xylose to furfural in biphasic solvent system,which was found to exhibit the best performance among the tested catalysts.The excellent performance of NbP could be explained by the better synergistic cooperation between Bro¨nsted and Lewis acid sites.Moreover,NbP showed good stability and no obvious deactivation or leaching of Nb could be observed after six continuous recycles.

  3. Modified cementless total coxofemoral prosthesis: development, implantation and clinical evaluation

    Directory of Open Access Journals (Sweden)

    S.A. Arias

    2013-12-01

    Full Text Available The aim of this study was to modify canine coxofemoral prostheses and the clinical evaluation of the implantation. Fifteen canine hips and femora of cadavers were used in order to study the surface points of modification in prostheses and develop a perforation guide. Femoral stems and acetabular components were perforated and coated with biphasic calcium phosphate layer. Twelve young adult male mongrel dogs were implanted with coxofemoral prostheses. Six were operated upon and implanted with cemented canine modular hip prostheses, establishing the control group. The remaining six were implanted with a novel design of cementless porous tricalcic phosphate-hydroxyapatite coated hip prostheses. Clinical and orthopedic performance, complications, and thigh muscular hypotrophy were assessed up to the 120th post-operatory day. After 120 days, animals with cementless prostheses had similar clinical and orthopedic performance compared to the cemented group despite the increased pain thigh hypotrophy. Animals that underwent cementless hip prosthesis evidenced more pain, compared to animals with cemented hip prosthesis that required longer recuperation time. No luxations, two fractures and two isquiatic neurapraxies were identified in the course of the study. Using both the cemented and the bioactive coated cementless model were suitable to dogs, showing clinical satisfactory results. Osseointegration and biological fixation were observed in the animals with the modified cementless hip prosthesis.

  4. Implant success!!!.....simplified

    Directory of Open Access Journals (Sweden)

    Luthra Kaushal

    2009-01-01

    Full Text Available The endeavor towards life-like restoration has helped nurture new vistas in the art and science of implant dentistry. The protocol of "restoration-driven implant placement" ensures that the implant is an apical extension of the ideal future restoration and not the opposite. Meticulous pre-implant evaluation of soft and hard tissues, diagnostic cast and use of aesthetic wax-up and radiographic template combined with surgical template can simplify the intricate roadmap for appropriate implant treatment. By applying the harmony of artistic skill, scientific knowledge and clinical expertise, we can simply master the outstanding implant success in requisites of aesthetics, phonetics and function.

  5. Synchronized oscillations of dimers in biphasic charged fd-virus suspensions

    Science.gov (United States)

    Kang, K.; Piao, S. H.; Choi, H. J.

    2016-08-01

    Micron-sized colloidal spheres that are dispersed in an isotropic-nematic biphasic host suspension of charged rods (fd-virus particles) are shown to spontaneously form dimers, which exhibit a synchronized oscillatory motion. Dimer formation is not observed in the monophase of isotropic and nematic suspensions. The synchronized oscillations of dimers are connected to the inhomogeneous state of the host suspension of charged rods (fd viruses) where nematic domains are in coexistence with isotropic regions. The synchronization of oscillations occurs in bulk states, in the absence of an external field. With a low field strength of an applied electric field, the synchronization is rather reduced, but it recovers again when the field is turned off. In this Rapid Communication, we report this observation as an example of the strange attractor, occurring in the mixture of PS (polystyrene) dimers in an isotropic-nematic coexistence biphasic fd-virus network. Furthermore, we highlight that the synchronization of PS-dimer oscillations is the result of a global bifurcation diagram, driven by a delicate balance between the short-attractive "twisted" interaction of PS dimers and long-ranged electrostatic repulsive interactions of charged fd rods. The interest is then in the local enhancement of "twist-nematic" elasticity in reorientation of the dimer oscillations. An analysis of image-time correlations is provided with the data movies and Fourier transforms of averaged orientations for the synchronized oscillations of dimers in the biphasic I -N coexistence concentration of charged fd-virus suspensions.

  6. Simulation by two calcium store models of myocardial dynamic properties: potentiation, staircase, and biphasic tension development.

    Science.gov (United States)

    Wussling, M; Szymanski, G

    1986-04-01

    Most considerations and models concerning myocardial dynamic properties e.g. potentiation and staircase, are based upon the existence of storage structures in the heart muscle cell. The phenomenon of biphasic tension development (or two-component contraction) in heart muscle preparations of several mammalian species suggests that the sarcoplasmic reticulum is one, but by no means the major, source of activator calcium for the contractile system. The simulation of dynamic properties including biphasic tension development was performed in two steps by a simple "two-Ca store-model" and by an "expanded two-Ca store-model" with following results: Increasing potentiation indicated a decrease in the degree of coupling between the Ca stores. A shift of the interval strength curve to lower intervals as well as a decrease of the steady state contraction height implies a decrease of both, the coupling and the leakage time constant. There was no standard relation between staircase phenomena and structure parameters. Analog displays showed a late (or second) component at prolongated stimulation intervals, in the transient phase after a rest period, in the case of perfectly coupled or uncoupled stores, and at great time constant tau p (which characterizes the calcium pump activity). It is concluded that the late component of biphasic tension development is due to direct activation by the transsarcolemmal Ca flux of the myofilaments, whereas the early component is caused by the release of stored calcium. In the absence of an early component neither potentiation nor marked treppe may be expected.

  7. Breast Implants: Saline vs. Silicone

    Science.gov (United States)

    ... differ in material and consistency, however. Saline breast implants Saline implants are filled with sterile salt water. ... of any age for breast reconstruction. Silicone breast implants Silicone implants are pre-filled with silicone gel — ...

  8. 16-Channel biphasic current-mode programmable charge balanced neural stimulation.

    Science.gov (United States)

    Li, Xiaoran; Zhong, Shunan; Morizio, James

    2017-08-14

    Neural stimulation is an important method used to activate or inhibit action potentials of the neuronal anatomical targets found in the brain, central nerve and peripheral nerve. The neural stimulator system produces biphasic pulses that deliver balanced charge into tissue from single or multichannel electrodes. The timing and amplitude of these biphasic pulses are precisely controlled by the neural stimulator software or imbedded algorithms. Amplitude mismatch between the anodic current and cathodic current of the biphasic pulse will cause permanently damage for the neural tissues. The main goal of our circuit and layout design is to implement a 16-channel biphasic current mode programmable neural stimulator with calibration to minimize the current mismatch caused by inherent complementary metal oxide semiconductor (CMOS) manufacturing processes. This paper presents a 16-channel constant current mode neural stimulator chip. Each channel consists of a 7-bit controllable current DAC used as sink and source current driver. To reduce the LSB quantization error and the current mismatch, an automatic calibration circuit and flow diagram is presented in this paper. There are two modes of operation of the stimulator chip-namely, stimulation mode and calibration mode. The chip also includes a digital interface used to control the stimulator parameters and calibration levels specific for each individual channel. This stimulator Application Specific Integrated Circuit (ASIC) is designed and fabricated in a 0.18 μm High-Voltage CMOS technology that allows for ±20 V power supply. The full-scale stimulation current was designed to be at 1 mA per channel. The output current was shown to be constant throughout the timing cycles over a wide range of electrode load impedances. The calibration circuit was also designed to reduce the effect of CMOS process variation of the P-channel metal oxide semiconductor (PMOS) and N-channel metal oxide semiconductor (NMOS) devices that will

  9. A novel ultrasound technique for detection of osteochondral defects in the ankle joint: a parametric and feasibility study.

    Science.gov (United States)

    Sarkalkan, Nazli; Loeve, Arjo J; van Dongen, Koen W A; Tuijthof, Gabrielle J M; Zadpoor, Amir A

    2015-01-01

    (Osteo)chondral defects (OCDs) in the ankle are currently diagnosed with modalities that are not convenient to use in long-term follow-ups. Ultrasound (US) imaging, which is a cost-effective and non-invasive alternative, has limited ability to discriminate OCDs. We aim to develop a new diagnostic technique based on US wave propagation through the ankle joint. The presence of OCDs is identified when a US signal deviates from a reference signal associated with the healthy joint. The feasibility of the proposed technique is studied using experimentally-validated 2D finite-difference time-domain models of the ankle joint. The normalized maximum cross correlation of experiments and simulation was 0.97. Effects of variables relevant to the ankle joint, US transducers and OCDs were evaluated. Variations in joint space width and transducer orientation made noticeable alterations to the reference signal: normalized root mean square error ranged from 6.29% to 65.25% and from 19.59% to 8064.2%, respectively. The results suggest that the new technique could be used for detection of OCDs, if the effects of other parameters (i.e., parameters related to the ankle joint and US transducers) can be reduced.

  10. Urinary incontinence - collagen implants

    Science.gov (United States)

    ... gov/ency/article/007373.htm Urinary incontinence - injectable implant To use the sharing features on this page, please enable JavaScript. Injectable implants are injections of material into the urethra to ...

  11. Implantable Medical Devices

    Science.gov (United States)

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Implantable Medical Devices Updated:Sep 16,2016 For Rhythm Control ... a Heart Attack Introduction Medications Surgical Procedures Implantable Medical Devices • Life After a Heart Attack • Heart Attack ...

  12. About Implantable Contraception

    Science.gov (United States)

    ... a tube was inserted, and get a new contraceptive implant on schedule or switch to another method of ... continue Possible Side Effects Young women who get contraceptive implants might notice such side effects as: irregular or ...

  13. Breast Reconstruction with Implants

    Science.gov (United States)

    Breast reconstruction with implants Overview By Mayo Clinic Staff Breast reconstruction is a surgical procedure that restores shape to ... treat or prevent breast cancer. One type of breast reconstruction uses breast implants — silicone devices filled with silicone ...

  14. Implantable electronic medical devices

    CERN Document Server

    Fitzpatrick, Dennis

    2014-01-01

    Implantable Electronic Medical Devices provides a thorough review of the application of implantable devices, illustrating the techniques currently being used together with overviews of the latest commercially available medical devices. This book provides an overview of the design of medical devices and is a reference on existing medical devices. The book groups devices with similar functionality into distinct chapters, looking at the latest design ideas and techniques in each area, including retinal implants, glucose biosensors, cochlear implants, pacemakers, electrical stimulation t

  15. Implantable Heart Aid

    Science.gov (United States)

    1984-01-01

    CPI's human-implantable automatic implantable defibrillator (AID) is a heart assist system, derived from NASA's space circuitry technology, that can prevent erratic heart action known as arrhythmias. Implanted AID, consisting of microcomputer power source and two electrodes for sensing heart activity, recognizes onset of ventricular fibrillation (VF) and delivers corrective electrical countershock to restore rhythmic heartbeat.

  16. Operation and Performance of a Biphase Turbine Power Plant at the Cerro Prieto Geothermal Field (Final Report)

    Energy Technology Data Exchange (ETDEWEB)

    Hays, Lance G. [Douglas Energy Company, Placentia, CA (United States)

    2000-09-01

    A full scale, wellhead Biphase turbine was manufactured and installed with the balance of plant at Well 103 of the Cerro Prieto geothermal resource in Baja, California. The Biphase turbine was first synchronized with the electrical grid of Comision Federal de Electricidad on August 20, 1997. The Biphase power plant was operated from that time until May 23, 2000, a period of 2 years and 9 months. A total of 77,549 kWh were delivered to the grid. The power plant was subsequently placed in a standby condition pending replacement of the rotor with a newly designed, higher power rotor and replacement of the bearings and seals. The maximum measured power output of the Biphase turbine, 808 kWe at 640 psig wellhead pressure, agreed closely with the predicted output, 840 kWe. When combined with the backpressure steam turbine the total output power from that flow would be increased by 40% above the power derived only from the flow by the present flash steam plant. The design relations used to predict performance and design the turbine were verified by these tests. The performance and durability of the Biphase turbine support the conclusion of the Economics and Application Report previously published, (Appendix A). The newly designed rotor (the Dual Pressure Rotor) was analyzed for the above power condition. The Dual Pressure Rotor would increase the power output to 2064 kWe by incorporating two pressure letdown stages in the Biphase rotor, eliminating the requirement for a backpressure steam turbine. The power plant availability was low due to deposition of solids from the well on the Biphase rotor and balance of plant problems. A great deal of plant down time resulted from the requirement to develop methods to handle the solids and from testing the apparatus in the Biphase turbine. Finally an online, washing method using the high pressure two-phase flow was developed which completely eliminated the solids problem. The availability of the Biphase turbine itself was 100

  17. Topical Delivery of Interferon Alpha by Biphasic Vesicles: Evidence for a Novel Nanopathway across the Stratum Corneum

    Energy Technology Data Exchange (ETDEWEB)

    Foldvari, M.; Badea, B; Wettig, S; Baboolal, D; Kumar, P; Creagh, A; Haynes, C

    2010-01-01

    Noninvasive delivery of macromolecules across intact skin is challenging but would allow for needle-free administration of many pharmaceuticals. Biphasic vesicles, a novel lipid-based topical delivery system, have been shown to deliver macromolecules into the skin. Investigation of the delivery mechanism of interferon alpha (IFN {alpha}), as a model protein, by biphasic vesicles could improve understanding of molecular transport through the stratum corneum and allow for the design of more effective delivery systems. The interaction of biphasic vesicles with human skin and isolated stratum corneum membrane was investigated by confocal microscopy, differential scanning calorimetry (DSC) and small- and wide-angle X-ray scattering (SAXS and WAXS). Confocal microscopy revealed that biphasic vesicles delivered IFN {alpha} intercellularly, to a depth of 70 {micro}m, well below the stratum corneum and into the viable epidermis. DSC and SAXS/WAXS data suggest that the interaction of biphasic vesicles with SC lipids resulted in the formation of a three-dimensional cubic Pn3m polymorphic phase by the molecular rearrangement of intercellular lipids. This cubic phase could be an intercellular permeation nanopathway that may explain the increased delivery of IFN {alpha} by biphasic vesicles. Liposomes and submicrometer emulsion (the individual building blocks of biphasic vesicles) separately and methylcellulose gel, an alternative topical vehicle, did not induce a cubic phase and delivered low amounts of IFN {alpha} below the stratum corneum. Molecular modeling of the cubic Pn3m phase and lamellar-to-cubic phase transitions provides a plausible mechanism for transport of IFN {alpha}. It is hypothesized that induction of a Pn3m cubic phase in stratum corneum lipids could make dermal and transdermal delivery of other macromolecules also possible.

  18. The Relationship of Anterior Cruciate Ligament Lesions and Osteochondral Lesions with Meniscal Tears in Patients Younger than Fifty Years of Age

    Directory of Open Access Journals (Sweden)

    Samed Ordu

    2014-09-01

    Full Text Available Aim: The purpose of this study was to determine the incidence of anterior cruciate ligament (ACL lesions and osteochondral lesions according to type and localization of the meniscal tear and age, gender in patients who have been arthroscopicaly treated, besides, to make the coexisting lesions more predictable in these patients. Methods: We retrospectively investigated 352 patients under 50 years of age who underwent surgery for a meniscal tear between 2008 and 2012. We scanned the surgical operation notes, preoperative questionnaires and the magnetic resonance imaging findings. We recorded patients who had ACL lesions, such as elongation, partial rupture and total rupture. Osteochondral lesions were classified according to the Outerbridge classification from grade 1 to grade 4. Results: Chondral lesions were present in 77.4% of patients with degenerative meniscal tears and in 63% of patients with radial meniscal tears. One the other hand, osteochondral lesions were observed in only 33.9% of patients with other types of meniscal tears. 46.6% of ACL lesions accompanied by meniscal tears with longitudinal pattern, such as longitudinal tears, bucket handle tears and root tears. For the other types of meniscal tears, this percentage was 20.7. When we excluded degenerative type meniscal tears, the mean age of the patients with radial tears was 40.86±9.03 years and the mean age of the patients with other types of tear was 35.44±9.44 years. The difference was statistically significant. Conclusion: We found close relationship between osteoarthritic chondral lesions and radial tears in the root of the posterior horn of the medial meniscus. On the other side, longitudinal tears were related with ACL lesions. (The Me­di­cal Bul­le­tin of Ha­se­ki 2014; 52: 177-80

  19. COCHLEAR IMPLANTATION: MY EXPERIENCE

    Directory of Open Access Journals (Sweden)

    Shankar

    2015-12-01

    Full Text Available Cochlear implant is a small, surgically implanted complex electronic device that can help to provide a sense of sound to a person with severe to profound sensorineural hearing loss. This type of hearing loss, typically involves damage to hair cells in the cochlea, as a result sound cannot reach the auditory nerve which usually receives information from hair cells. A cochlear implant skips the damaged hair cells and to stimulate the auditory nerve directly. An implant does not restore normal hearing, instead it can give a deaf person a useful representation of sounds in the environment and help him or her to understand speech. I am here presenting this article in relation to the indications, intraoperative and postoperative complications of cochlear implantation in our institute since January 2013. Children who receive implants at earlier age, outperform their peers who are implanted at a later age. This is reflected in all the areas of speech and language development.

  20. Electroporation adopting trains of biphasic pulses enhances in vitro and in vivo the cytotoxic effect of doxorubicin on multidrug resistant colon adenocarcinoma cells (LoVo).

    Science.gov (United States)

    Meschini, Stefania; Condello, Maria; Lista, Pasquale; Vincenzi, Bruno; Baldi, Alfonso; Citro, Gennaro; Arancia, Giuseppe; Spugnini, Enrico P

    2012-09-01

    Few articles in the literature have focused on electroporation as a strategy to reverse multidrug resistance (MDR) of tumour cells and they are mostly limited to the improved efficacy of bleomycin. We tested the application of trains of biphasic pulses to cell suspensions and to murine xenografts as a strategy to increase the uptake of doxorubicin (DOX) and to enhance its cytotoxicity against chemoresistant cells. The human colon adenocarcinoma cell line LoVo DX, expressing MDR phenotype with high levels of P-glycoprotein (P-gp), has been used. The in vitro and in vivo studies gave the following results: (i) the application of the electric pulses to the cell suspension, immediately before DOX administration, induced a significant increase of drug retention; (ii) confocal microscopy observations showed a remarkable increase of intranuclear accumulation of DOX induced by electroporation; (iii) cell survival assay revealed a decrease of cell viability in the cultures treated with the combination of electroporation and doxorubicin; (iv) scanning electron microscopy observations revealed consistent morphological changes after the combined exposure to electroporation and doxorubicin; (v) in implanted mice the combined treatment induced an evident slowdown on the tumour growth when compared to treatment with DOX alone; (vi) histopathological analysis evidenced tumour destruction and its replacement by scar tissue in the tumours treated with the combination of doxorubicin and electroporation.

  1. Modeling the impact of prostate edema on LDR brachytherapy: a Monte Carlo dosimetry study based on a 3D biphasic finite element biomechanical model.

    Science.gov (United States)

    Mountris, K A; Bert, J; Noailly, J; Aguilera, A Rodriguez; Valeri, A; Pradier, O; Schick, U; Promayon, E; Ballester, M A Gonzalez; Troccaz, J; Visvikis, D

    2017-03-21

    Prostate volume changes due to edema occurrence during transperineal permanent brachytherapy should be taken under consideration to ensure optimal dose delivery. Available edema models, based on prostate volume observations, face several limitations. Therefore, patient-specific models need to be developed to accurately account for the impact of edema. In this study we present a biomechanical model developed to reproduce edema resolution patterns documented in the literature. Using the biphasic mixture theory and finite element analysis, the proposed model takes into consideration the mechanical properties of the pubic area tissues in the evolution of prostate edema. The model's computed deformations are incorporated in a Monte Carlo simulation to investigate their effect on post-operative dosimetry. The comparison of Day1 and Day30 dosimetry results demonstrates the capability of the proposed model for patient-specific dosimetry improvements, considering the edema dynamics. The proposed model shows excellent ability to reproduce previously described edema resolution patterns and was validated based on previous findings. According to our results, for a prostate volume increase of 10-20% the Day30 urethra D10 dose metric is higher by 4.2%-10.5% compared to the Day1 value. The introduction of the edema dynamics in Day30 dosimetry shows a significant global dose overestimation identified on the conventional static Day30 dosimetry. In conclusion, the proposed edema biomechanical model can improve the treatment planning of transperineal permanent brachytherapy accounting for post-implant dose alterations during the planning procedure.

  2. Modeling the impact of prostate edema on LDR brachytherapy: a Monte Carlo dosimetry study based on a 3D biphasic finite element biomechanical model

    Science.gov (United States)

    Mountris, K. A.; Bert, J.; Noailly, J.; Rodriguez Aguilera, A.; Valeri, A.; Pradier, O.; Schick, U.; Promayon, E.; Gonzalez Ballester, M. A.; Troccaz, J.; Visvikis, D.

    2017-03-01

    Prostate volume changes due to edema occurrence during transperineal permanent brachytherapy should be taken under consideration to ensure optimal dose delivery. Available edema models, based on prostate volume observations, face several limitations. Therefore, patient-specific models need to be developed to accurately account for the impact of edema. In this study we present a biomechanical model developed to reproduce edema resolution patterns documented in the literature. Using the biphasic mixture theory and finite element analysis, the proposed model takes into consideration the mechanical properties of the pubic area tissues in the evolution of prostate edema. The model’s computed deformations are incorporated in a Monte Carlo simulation to investigate their effect on post-operative dosimetry. The comparison of Day1 and Day30 dosimetry results demonstrates the capability of the proposed model for patient-specific dosimetry improvements, considering the edema dynamics. The proposed model shows excellent ability to reproduce previously described edema resolution patterns and was validated based on previous findings. According to our results, for a prostate volume increase of 10–20% the Day30 urethra D10 dose metric is higher by 4.2%–10.5% compared to the Day1 value. The introduction of the edema dynamics in Day30 dosimetry shows a significant global dose overestimation identified on the conventional static Day30 dosimetry. In conclusion, the proposed edema biomechanical model can improve the treatment planning of transperineal permanent brachytherapy accounting for post-implant dose alterations during the planning procedure.

  3. Osteoinduction and survival of osteoblasts and bone-marrow stromal cells in 3D biphasic calcium phosphate scaffolds under static and dynamic culture conditions.

    Science.gov (United States)

    Rath, Subha N; Strobel, Leonie A; Arkudas, Andreas; Beier, Justus P; Maier, Anne-Kathrin; Greil, Peter; Horch, Raymund E; Kneser, Ulrich

    2012-10-01

    In many tissue engineering approaches, the basic difference between in vitro and in vivo conditions for cells within three-dimensional (3D) constructs is the nutrition flow dynamics. To achieve comparable results in vitro, bioreactors are advised for improved cell survival, as they are able to provide a controlled flow through the scaffold. We hypothesize that a bioreactor would enhance long-term differentiation conditions of osteogenic cells in 3D scaffolds. To achieve this either primary rat osteoblasts or bone marrow stromal cells (BMSC) were implanted on uniform-sized biphasic calcium phosphate (BCP) scaffolds produced by a 3D printing method. Three types of culture conditions were applied: static culture without osteoinduction (Group A); static culture with osteoinduction (Group B); dynamic culture with osteoinduction (Group C). After 3 and 6 weeks, the scaffolds were analysed by alkaline phosphatase (ALP), dsDNA amount, SEM, fluorescent labelled live-dead assay, and real-time RT-PCR in addition to weekly alamarBlue assays. With osteoinduction, increased ALP values and calcium deposition are observed; however, under static conditions, a significant decrease in the cell number on the biomaterial is observed. Interestingly, the bioreactor system not only reversed the decreased cell numbers but also increased their differentiation potential. We conclude from this study that a continuous flow bioreactor not only preserves the number of osteogenic cells but also keeps their differentiation ability in balance providing a suitable cell-seeded scaffold product for applications in regenerative medicine.

  4. Bone Formation with Deproteinized Bovine Bone Mineral or Biphasic Calcium Phosphate in the Presence of Autologous Platelet Lysate: Comparative Investigation in Rabbit

    Directory of Open Access Journals (Sweden)

    Carole Chakar

    2014-01-01

    Full Text Available Bone substitutes alone or supplemented with platelet-derived concentrates are widely used to promote bone regeneration but their potency remains controversial. The aim of this study was, therefore, to compare the regenerative potential of preparations containing autologous platelet lysate (APL and particles of either deproteinized bovine bone mineral (DBBM or biphasic calcium phosphate (BCP, two bone substitutes with different resorption patterns. Rabbit APL was prepared by freeze-thawing a platelet suspension. Critical-size defects in rabbit femoral condyle were filled with DBBM or DBBM+APL and BCP or BCP+APL. Rabbits were sacrificed after six weeks and newly formed bone and residual implanted material were evaluated using nondemineralized histology and histomorphometry. New bone was observed around particles of all fillers tested. In the defects filled with BCP, the newly formed bone area was greater (70%; P<0.001 while the residual material area was lower (60%; P<0.001 than that observed in those filled with DBBM. New bone and residual material area of defects filled with either APL+DBBM or APL+BCP were similar to those observed in those filled with the material alone. In summary, osteoconductivity and resorption of BCP were greater than those of DBBM, while APL associated with either DBBM or BCP did not have an additional benefit.

  5. Implantes transcigomáticos Traszygomatic implants

    OpenAIRE

    B. Fernández Ateca; M. Colorado Bonnin; C. Gay Escoda

    2004-01-01

    Los implantes cigomáticos, originariamente diseñados por Branemark en 1989, son implantes de cabeza en 45 grados, de 4'5 milímetros de diámetro en su parte más ancha, y que pueden medir entre 30 y 50 milímetros de longitud. Se insertan desde la parte palatina del proceso alveolar, siguiendo la cresta cigomática-alveolar hasta anclarse en el cuerpo del malar, y en el caso de pacientes maxilectomizados, entrando directamente en el cuerpo del malar. Estos implantes ofrecen una alternativa más al...

  6. Purification of Helicobacter suis Strains From Biphasic Cultures by Single Colony Isolation: Influence on Strain Characteristics.

    Science.gov (United States)

    Liang, Jungang; De Bruyne, Ellen; Ducatelle, Richard; Smet, Annemieke; Haesebrouck, Freddy; Flahou, Bram

    2015-06-01

    Helicobacter (H.) suis causes gastritis and decreased weight gain in pigs. It is also the most prevalent non-Helicobacter pylori Helicobacter species in humans with gastric disease. H. suis is extremely fastidious, and so far, biphasic culture conditions were essential for isolation and culture, making it impossible to obtain single colonies. Hence, cultures obtained from an individual animal may contain multiple H. suis strains, which is undesirable for experiments aiming for instance at investigating H. suis strain differences. Pure cultures of H. suis were established by growing bacteria as colonies on 1% brucella agar plates, followed by purification and enrichment by biphasic subculture. Characteristics of these single colony-derived strains were compared with those of their parent strains using multilocus sequence typing (MLST) and by studying bacterium-host interactions using a gastric epithelial cell line and Mongolian gerbil model. The purification/enrichment procedure required a nonstop culture of several weeks. For 4 of 17 H. suis strains, MLST revealed differences between parental and single colony-derived strains. For three of four single colony-derived strains tested, the cell death-inducing capacity was higher than for the parental strain. One single colony-derived strain lost its capacity to colonize Mongolian gerbils. For the four other strains tested, colonization capacity and histopathologic changes were similar to what has been described when using strains with only a history of limited biphasic culture. A method was developed to obtain single colony-derived H. suis strains, but this procedure may affect the bacterial genotype and phenotype. © 2015 John Wiley & Sons Ltd.

  7. A Lagrange multiplier mixed finite element formulation for three-dimensional contact of biphasic tissues.

    Science.gov (United States)

    Yang, Taiseung; Spilker, Robert L

    2007-06-01

    A three-dimensional (3D) contact finite element formulation has been developed for biological soft tissue-to-tissue contact analysis. The linear biphasic theory of Mow, Holmes, and Lai (1984, J. Biomech., 17(5), pp. 377-394) based on continuum mixture theory, is adopted to describe the hydrated soft tissue as a continuum of solid and fluid phases. Four contact continuity conditions derived for biphasic mixtures by Hou et al. (1989, ASME J. Biomech. Eng., 111(1), pp. 78-87) are introduced on the assumed contact surface, and a weighted residual method has been used to derive a mixed velocity-pressure finite element contact formulation. The Lagrange multiplier method is used to enforce two of the four contact continuity conditions, while the other two conditions are introduced directly into the weighted residual statement. Alternate formulations are possible, which differ in the choice of continuity conditions that are enforced with Lagrange multipliers. Primary attention is focused on a formulation that enforces the normal solid traction and relative fluid flow continuity conditions on the contact surface using Lagrange multipliers. An alternate approach, in which the multipliers enforce normal solid traction and pressure continuity conditions, is also discussed. The contact nonlinearity is treated with an iterative algorithm, where the assumed area is either extended or reduced based on the validity of the solution relative to contact conditions. The resulting first-order system of equations is solved in time using the generalized finite difference scheme. The formulation is validated by a series of increasingly complex canonical problems, including the confined and unconfined compression, the Hertz contact problem, and two biphasic indentation tests. As a clinical demonstration of the capability of the contact analysis, the gleno-humeral joint contact of human shoulders is analyzed using an idealized 3D geometry. In the joint, both glenoid and humeral head

  8. Biphasic fermentation is an efficient strategy for the overproduction of δ-endotoxin from Bacillus thuringiensis.

    Science.gov (United States)

    Jisha, Veloorvalappil Narayanan; Smitha, Robinson Babysarojam; Priji, Prakasan; Sajith, Sreedharan; Benjamin, Sailas

    2015-02-01

    This study illustrates a biphasic solid-state fermentation (SSF) strategy for the overproduction of δ-endotoxin from Bacillus thuringiensis subsp. kurstaki (Btk) and also purification of δ-endotoxin from the solid-fermented medium. The fermentation strategy had two phases (biphasic); i.e., the first short phase was semisolid state (12 h), and the remaining long phase was strict SSF. To achieve the biphasic SSF, after 12 h (150 rpm, 37 °C) fermentation of the medium [Luria-Bertani (LB) supplemented with 30 % (w/v) raw soybean flour (phase I)], the supernatant in it was completely centrifuged out (1,000 × g, 10 min) aseptically for harvesting the extracellular enzymes as by-product. The resultant wet solid matter without free-flowing liquid but with embedded Btk was incubated 60 h more (phase II) for enhancing δ-endotoxin production at static condition (37 °C). Coupled with this, δ-endotoxin was purified by the modified phase separation method, and its purity was physically confirmed by both staining and microscopic techniques. The maximum δ-endotoxin yield from solid medium (48 h) was 15.8 mg/mL (recovery was 55-59 %) LB-equivalent, while that of LB control (recovery was 95 %) was only 0.43 mg/mL (72 h), i.e., thus, in comparison, 36.74-fold more yield in solid medium obtained by 24 h less gestation period. The purified crystal proteins showed apparent molecular weights (MWs) of 45, 35, and 6 kDa on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Briefly, this unique study physically demonstrates how Btk δ-endotoxin is purified (95-99 % purity) from solid-fermented matter for the first time, coupled with its overproduction at the expense of only 21.5 % higher production cost.

  9. Generic Model-Based Tailor-Made Design and Analysis of Biphasic Reaction Systems

    DEFF Research Database (Denmark)

    Anantpinijwatna, Amata

    contribution of this thesis is the development of a systematic modelling framework for the biphasic reaction system. The developed framework consists of three modules describing phase equilibria, reactions and mass transfer, and material balances of such processes. Correlative and predictive thermodynamic......-elementary reaction rate laws. Extents of reaction are used to calculate the species material balances. The resulting mathematical model contains temperature dependent reaction rate parameters,equilibrium constants, and partition coefficients; where only the reaction rates are to be regressed to a minimum of time...

  10. A Novel Ionic Liquid/water Biphasic System for the Preparation of Oximes

    Institute of Scientific and Technical Information of China (English)

    Hui Mou LUO; Yi Qun LI; Wen Jie ZHENG

    2005-01-01

    A variety of carbonyl compounds can be converted into oximes efficiently and conveniently in a novel ionic liquid/water bi-phasic system in the presence of sodium bicarbonate at ambient temperature. The ionic liquid 1-butyl-3-methyl imidazolium hexafluorophosphate [bmim]PF6 is immiscible with water or diethyl ether and can be easily recycled for reuse without noticeable droping in activity after separation of the products. The protocol is rapid, the yields are excellent, the method is simple and the ionic liquid can be reused.

  11. Use of Biphasic Continuous Positive Airway Pressure in Premature Infant with Cleft Lip–Cleft Palate

    Directory of Open Access Journals (Sweden)

    Lovya George

    2015-10-01

    Full Text Available Preterm infants (PIs often require respiratory support due to surfactant deficiency. Early weaning from mechanical ventilation to noninvasive respiratory support decreases ventilation-associated irreversible lung damage. This wean is particularly challenging in PIs with cleft lip and cleft palate due to anatomical difficulties encountered in maintaining an adequate seal for positive pressure ventilation. PI with a cleft lip and palate often fail noninvasive respiratory support and require continued intubation and mechanical ventilation. We are presenting the first case report of a PI with cleft lip and palate who was managed by biphasic nasal continuous positive airway pressure.

  12. Lipase in biphasic alginate beads as a biocatalyst for esterification of butyric acid and butanol in aqueous media.

    Science.gov (United States)

    Ng, Choong Hey; Yang, Kun-Lin

    2016-01-01

    Esterification of organic acids and alcohols in aqueous media is very inefficient due to thermodynamic constraints. However, fermentation processes used to produce organic acids and alcohols are often conducted in aqueous media. To produce esters in aqueous media, biphasic alginate beads with immobilized lipase are developed for in situ esterification of butanol and butyric acid. The biphasic beads contain a solid matrix of calcium alginate and hexadecane together with 5 mg/mL of lipase as the biocatalyst. Hexadecane in the biphasic beads serves as an organic phase to facilitate the esterification reaction. Under optimized conditions, the beads are able to catalyze the production of 0.16 mmol of butyl butyrate from 0.5 mmol of butyric acid and 1.5 mmol of butanol. In contrast, when monophasic beads (without hexadecane) are used, only trace amount of butyl butyrate is produced. One main application of biphasic beads is in simultaneous fermentation and esterification (SFE) because the organic phase inside the beads is very stable and does not leach out into the culture medium. SFE is successfully conducted with an esterification yield of 6.32% using biphasic beads containing iso-octane even though the solvent is proven toxic to the butanol-producing Clostridium spp.

  13. Implantes transcigomáticos Traszygomatic implants

    Directory of Open Access Journals (Sweden)

    B. Fernández Ateca

    2004-12-01

    Full Text Available Los implantes cigomáticos, originariamente diseñados por Branemark en 1989, son implantes de cabeza en 45 grados, de 4'5 milímetros de diámetro en su parte más ancha, y que pueden medir entre 30 y 50 milímetros de longitud. Se insertan desde la parte palatina del proceso alveolar, siguiendo la cresta cigomática-alveolar hasta anclarse en el cuerpo del malar, y en el caso de pacientes maxilectomizados, entrando directamente en el cuerpo del malar. Estos implantes ofrecen una alternativa más al cirujano en el momento de planificar un tratamiento protésico-rehabilitador implantosoportado. Sobretodo, en aquellos pacientes con un maxilar superior atrófico en el que no se pueden realizar injertos óseos o estos han fracasado. El objetivo de este artículo es proponer el protocolo quirúrgico de colocación de los implantes trascigomáticos y revisar la literatura actual sobre la evolución clínica de estos implantes.The zygomatic implants, originally designed by Branemark in 1989, are implants with a 45 degree inclined head, 4'5 millimetre diameter at their widest part and measuring between 30 and 50 millimetres in length. They are inserted from the palatine side of the alveolar process, following the zygomatic-alveolar edge and anchor in the body of the zygomatic bone. In the case of maxillectomized patients, they are inserted directly in the body of the malar bone. These implants offer an additional alternative to the surgeon when planning an implant supported rehabilitation treatment; specially in those patients with an atrophic maxilla in which osseous grafts cannot be realized or these grafts have failed. The objective of this article is to propose the surgical,protocol of placement of traszygomatic implants and to check the current literature on the clinical evolution of these implants.

  14. 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.

  15. 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

  16. Vestibular implantation and longitudinal electrical stimulation of the semicircular canal afferents in human subjects.

    Science.gov (United States)

    Phillips, James O; Ling, Leo; Nie, Kaibao; Jameyson, Elyse; Phillips, Christopher M; Nowack, Amy L; Golub, Justin S; Rubinstein, Jay T

    2015-06-01

    Animal experiments and limited data in humans suggest that electrical stimulation of the vestibular end organs could be used to treat loss of vestibular function. In this paper we demonstrate that canal-specific two-dimensionally (2D) measured eye velocities are elicited from intermittent brief 2 s biphasic pulse electrical stimulation in four human subjects implanted with a vestibular prosthesis. The 2D measured direction of the slow phase eye movements changed with the canal stimulated. Increasing pulse current over a 0-400 μA range typically produced a monotonic increase in slow phase eye velocity. The responses decremented or in some cases fluctuated over time in most implanted canals but could be partially restored by changing the return path of the stimulation current. Implantation of the device in Meniere's patients produced hearing and vestibular loss in the implanted ear. Electrical stimulation was well tolerated, producing no sensation of pain, nausea, or auditory percept with stimulation that elicited robust eye movements. There were changes in slow phase eye velocity with current and over time, and changes in electrically evoked compound action potentials produced by stimulation and recorded with the implanted device. Perceived rotation in subjects was consistent with the slow phase eye movements in direction and scaled with stimulation current in magnitude. These results suggest that electrical stimulation of the vestibular end organ in human subjects provided controlled vestibular inputs over time, but in Meniere's patients this apparently came at the cost of hearing and vestibular function in the implanted ear.

  17. Invariance of the magnetic behavior and AMI in ferromagnetic biphase films with distinct non-magnetic metallic spacers

    Energy Technology Data Exchange (ETDEWEB)

    Silva, E.F. [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Gamino, M. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Instituto de Física, Universidade Federal do Rio Grande de Sul, 91501-970 Porto Alegre, RS (Brazil); Andrade, A.M.H. de [Instituto de Física, Universidade Federal do Rio Grande de Sul, 91501-970 Porto Alegre, RS (Brazil); Vázquez, M. [Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid (Spain); Correa, M.A. [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Bohn, F., E-mail: felipebohn@fisica.ufrn.br [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil)

    2017-02-01

    We investigate the quasi-static magnetic, magnetotransport, and dynamic magnetic properties in ferromagnetic biphase films with distinct non-magnetic metallic spacer layers. We observe that the nature of the non-magnetic metallic spacer material does not have significant influence on the overall biphase magnetic behavior, and, consequently, on the magnetotransport and dynamic magnetic responses. We focus on the magnetoimpedance effect and verify that the films present asymmetric magnetoimpedance effect. Moreover, we explore the possibility of tuning the linear region of the magnetoimpedance curves around zero magnetic field by varying the probe current frequency in order to achieve higher sensitivity values. The invariance of the magnetic behavior and the asymmetric magnetoimpedance effect in ferromagnetic biphase films with distinct non-magnetic metallic spacers place them as promising candidates for probe element and open possibilities to the development of lower-cost high sensitivity linear magnetic field sensor devices.

  18. Production of Phytotoxic Metabolite Using Biphasic Fermentation System from Strain C1136 of Lasiodiplodia pseudotheobromae, a Potential Bioherbicidal Agent

    Directory of Open Access Journals (Sweden)

    Charles Oluwaseun ADETUNJI

    2017-09-01

    Full Text Available Formulation of effective and environmental friendly bioherbicides depends on the type of fermentation medium used for the production of phytotoxic metabolites. The effect of biomass, colony forming unit and the phytotoxic metabolite produced from the biphasic fermentation was carried out, while the phytotoxic metabolite was tested in vivo and in-vitro on Echinochola crus-galli and dicotyledonous Chromolaena odorata. The mutant strain of Lasiodiplodia pseudotheobromae C1136 (Lp90 produced the highest amount of conidia and the largest necrotic area on the two tested weeds when compared to its wild strain in the different biphasic media combinations. The study revealed that the biphasic system containing PDB + rice produced the highest bioherbicidal activities. Therefore, the phytotoxic metabolites from strain C1136 are suggested for large scale production of bioherbicides for the management of weeds in conventional farming to improve yield and enhance food security.

  19. Fabrication of Biphase BiVO4 Particles with Enhanced Photocatalytic Performance via a Surfactant-Free Hydrothermal Route

    Science.gov (United States)

    Qian, Hongzhi; Lai, Min; Huang, Xiaogu; Wang, Wei; Xu, Chaoqi; Yong, Haibo; Wen, Yan; Zhou, Yingjie

    2016-04-01

    Biphase bismuth vanadate (BiVO4) particles have been synthesized using a surfactant-free hydrothermal strategy. Biphase BiVO4 were formed at pH=3, 5 and 7 with a bandgap between 2.28eV and 2.86eV, which are those of monoclinic and tetragonal phases, respectively. Photocatalytic tests on the degradation of rhodamine B (RhB) under visible-light irradiation showed that biphase BiVO4 with both monoclinic and tetragonal structures synthesized at pH=3 achieved enhanced photocatalytic performance in comparison with pure monoclinic and tetragonal phases, which was attributed to the heterostructures leading to low recombination rate of electron-hole pairs.

  20. Fluorocarbon compatibilized gold-silica nanocomposites for recyclable regioselective hydroamination of alkynes in a fluorous biphasic system

    Science.gov (United States)

    Merican, Zulkifli; Vu, Bao Khanh; Solovyeva, Vera A.; Rodionov, Valentin O.; Khe, Cheng Seong; Rajalingam, Sokkalingam; Vasant, Pandian

    2016-11-01

    The synthesis and characterization of the mesoporous silica-supported gold (Au@mSiO2) nanoparticles compatibilized with the outer shelled superhydrophobic fluorous (F) "tails" was described. The concept of fluorous biphasic separation was applied in the recycling of the synthesized fluorous material during hydroamination reactions of various alkynes. In the presence of perfluoromethylcyclohexane and heptane as a biphasic liquid system, the F-Au@mSiO2 was found to be a highly active catalyst for hydroamination of various alkynes with anilines, and a near quantitative yield for an imine product and produced a relatively minimal formation of a corresponding hydrolyzed ketone by-product. If perfluoromethylcyclohexane and heptane was used as a biphasic solvent, hydroamination at a lower reaction temperature can also be realized leading to an improved recyclability and conversion.

  1. Invariance of the magnetic behavior and AMI in ferromagnetic biphase films with distinct non-magnetic metallic spacers

    Science.gov (United States)

    Silva, E. F.; Gamino, M.; Andrade, A. M. H. de; Vázquez, M.; Correa, M. A.; Bohn, F.

    2017-02-01

    We investigate the quasi-static magnetic, magnetotransport, and dynamic magnetic properties in ferromagnetic biphase films with distinct non-magnetic metallic spacer layers. We observe that the nature of the non-magnetic metallic spacer material does not have significant influence on the overall biphase magnetic behavior, and, consequently, on the magnetotransport and dynamic magnetic responses. We focus on the magnetoimpedance effect and verify that the films present asymmetric magnetoimpedance effect. Moreover, we explore the possibility of tuning the linear region of the magnetoimpedance curves around zero magnetic field by varying the probe current frequency in order to achieve higher sensitivity values. The invariance of the magnetic behavior and the asymmetric magnetoimpedance effect in ferromagnetic biphase films with distinct non-magnetic metallic spacers place them as promising candidates for probe element and open possibilities to the development of lower-cost high sensitivity linear magnetic field sensor devices.

  2. Programmed Application of Transforming Growth Factor β3 and Rac1 Inhibitor NSC23766 Committed Hyaline Cartilage Differentiation of Adipose-Derived Stem Cells for Osteochondral Defect Repair.

    Science.gov (United States)

    Zhu, Shouan; Chen, Pengfei; Wu, Yan; Xiong, Si; Sun, Heng; Xia, Qingqing; Shi, Libing; Liu, Huanhuan; Ouyang, Hong Wei

    2014-10-01

    Hyaline cartilage differentiation is always the challenge with application of stem cells for joint repair. Transforming growth factors (TGFs) and bone morphogenetic proteins can initiate cartilage differentiation but often lead to hypertrophy and calcification, related to abnormal Rac1 activity. In this study, we developed a strategy of programmed application of TGFβ3 and Rac1 inhibitor NSC23766 to commit the hyaline cartilage differentiation of adipose-derived stem cells (ADSCs) for joint cartilage repair. ADSCs were isolated and cultured in a micromass and pellet culture model to evaluate chondrogenic and hypertrophic differentiation. The function of Rac1 was investigated with constitutively active Rac1 mutant and dominant negative Rac1 mutant. The efficacy of ADSCs with programmed application of TGFβ3 and Rac1 inhibitor for cartilage repair was studied in a rat model of osteochondral defects. The results showed that TGFβ3 promoted ADSCs chondro-lineage differentiation and that NSC23766 prevented ADSC-derived chondrocytes from hypertrophy in vitro. The combination of ADSCs, TGFβ3, and NSC23766 promoted quality osteochondral defect repair in rats with much less chondrocytes hypertrophy and significantly higher International Cartilage Repair Society macroscopic and microscopic scores. The findings have illustrated that programmed application of TGFβ3 and Rac1 inhibitor NSC23766 can commit ADSCs to chondro-lineage differentiation and improve the efficacy of ADSCs for cartilage defect repair. These findings suggest a promising stem cell-based strategy for articular cartilage repair. ©AlphaMed Press.

  3. Biphasic pulses enhance bleomycin efficacy in a spontaneous canine genital tumor model of chemoresistance: Sticker sarcoma

    Directory of Open Access Journals (Sweden)

    Citro Gennaro

    2008-11-01

    Full Text Available Abstract Sticker's sarcoma (also known as transmissible venereal tumor is a horizontally transmitted neoplasm of the dog, that is passed with coitus. It is a locally aggressive tumor with a low tendency to metastatic spread. The most common locations are the genitals, the nose, the perianal area. Standard treatment consists with chemotherapy with vincristine, however other therapies such as, cryotherapy, immunotherapy or, in selected cases, radiation therapy, have been reported. In this article we describe the outcome of a small cohort of canine patients, with chemotherapy resistant transmissible venereal tumor (TVT, treated with bleomycin selectively driven by trains of biphasic pulses (electrochemotherapy. Three canine patients, with refractory TVT, entered the study and received two sessions of ECT under sedation. The pets had local injection of bleomycin at the concentration of 1.5 mg/ml and five minutes after the chemotherapy, trains of 8 biphasic electric pulses lasting 50 + 50 μs each, with 1 ms interpulse intervals, were delivered by means of modified caliper or, for difficult districts, through paired needle electrode. All the patients responded to the treatment and are still in remission at different times. Electrochemotherapy appears as a safe and efficacious modality for the treatment of TVT and warrants further investigations.

  4. Is there an Optimal Shape of the Defibrillation Shock: Constant Current vs. Pulsed Biphasic Waveforms

    Directory of Open Access Journals (Sweden)

    Ivan Dotsinsky

    2013-04-01

    Full Text Available Three waveforms for transthoracic defibrillation are assessed and compared: the Pulsed Biphasic Waveform (PBW, the Rectilinear Biphasic Waveform (RBW, and the "lossless" constant current (LLCC pulses. Two indices are introduced: 1 kf = W/W0 - the ratio between the delivered energy W and the energy W0 of a rectangular pulse with the same duration and electric charge; 2 ηC = W/WC0 - the level of utilizing the initially loaded capacitor energy WC0. The envisioned comparative study shows that ηC index is favorable for both PBW and LLCC, while kf of both RBW and LLCC demonstrates advantage over the PBW in the range of small inter-electrode thoracic impedances below 80 Ω. Some design considerations are also discussed. The attractive LLCC concept needs large and heavy inductive coil to support the constant current amplitude, besides it is capable to induce strong electromagnetic influences due to the complex current control. The RBW technology controls the delivery of current through a series of internal resistors which are, however, a source of high heat losses. The PBW implements controlled duty cycle of high-frequency chopped pulses to adapt the energy delivery in respect of the patient impedance measured at the beginning of the shock. PBW technology makes use of small capacitors which allows the construction of light weight and small-size portable devices for transthoracic defibrillation.

  5. Biphasic electrical currents stimulation promotes both proliferation and differentiation of fetal neural stem cells.

    Directory of Open Access Journals (Sweden)

    Keun-A Chang

    Full Text Available The use of non-chemical methods to differentiate stem cells has attracted researchers from multiple disciplines, including the engineering and the biomedical fields. No doubt, growth factor based methods are still the most dominant of achieving some level of proliferation and differentiation control--however, chemical based methods are still limited by the quality, source, and amount of the utilized reagents. Well-defined non-chemical methods to differentiate stem cells allow stem cell scientists to control stem cell biology by precisely administering the pre-defined parameters, whether they are structural cues, substrate stiffness, or in the form of current flow. We have developed a culture system that allows normal stem cell growth and the option of applying continuous and defined levels of electric current to alter the cell biology of growing cells. This biphasic current stimulator chip employing ITO electrodes generates both positive and negative currents in the same culture chamber without affecting surface chemistry. We found that biphasic electrical currents (BECs significantly increased the proliferation of fetal neural stem cells (NSCs. Furthermore, BECs also promoted the differentiation of fetal NSCs into neuronal cells, as assessed using immunocytochemistry. Our results clearly show that BECs promote both the proliferation and neuronal differentiation of fetal NSCs. It may apply to the development of strategies that employ NSCs in the treatment of various neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases.

  6. In situ synthesis of silicon-substituted biphasic calcium phosphate and their performance in vitro

    Science.gov (United States)

    Song, Chang-Weon; Kim, Tae-Wan; Kim, Dong-Hyun; Jin, Hyeong-Ho; Hwang, Kyu-Hong; Lee, Jong Kook; Park, Hong-Chae; Yoon, Seog-Young

    2012-01-01

    In situ preparation of silicon (Si) substituted biphasic calcium phosphate (BCP) of hydroxyapatite (HAp)/ β-tricalcium phosphate (β-TCP) were carried out through aqueous co-precipitation method. The concentrations of added silicon were varied with the phosphor in order to obtain constant Ca/(P+Si) ratios of 1.602. X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy were used to characterize the structure of synthesized silicon substituted BCP powders. The characterization revealed that the formation of biphasic mixtures of different HAp/ β-TCP ratios was dependent on the content of silicon. After immersing in Hanks' balanced salt solution (HBSS) for 1 week, 3 wt% silicon substituted BCP powders were degraded and precipitation started to be formed with small granules consisting of number of flake-like crystal onto the surface of synthesized powders. In the case of 1 wt% silicon substituted BCP powders, the degradation behavior was detected after immersion in HBSS for 3 weeks. On the other hand, silicon unsubtituted BCP powders were not degraded even after that duration. On the basis of these results, silicon substituted BCP is able to develop a new apatite phase on the surface in contact with physiological fluids faster than BCP does. This enhanced reactivity resulted in reduction for the stability of the β-TCP structure due to SiO4 tetrahedral distortion and disorder at the hydroxyl site when silicon incorporates into BCP.

  7. Biphasic products of dicalcium phosphate-rich cement with injectability and nondispersibility

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Chia-Ling [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, Feng Chia University, Taichung, 407, Taiwan (China); Dental Medical Devices and Materials Research Center, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Chen, Jian-Chih [Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Department of Orthopaedics, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Hung, Chun-Cheng; Wang, Jen-Chyan [Dental Medical Devices and Materials Research Center, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Tien, Yin-Chun [Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Department of Orthopaedics, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Chen, Wen-Cheng, E-mail: wencchen@fcu.edu.tw [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, Feng Chia University, Taichung, 407, Taiwan (China)

    2014-06-01

    In this study, a calcium phosphate cement was developed using tetracalcium phosphate and surface-modified dicalcium phosphate anhydrous (DCPA). This developed injectable bone graft substitute can be molded to the shape of the bone cavity and set in situ through the piping system that has an adequate mechanical strength, non-dispersibility, and biocompatibility. The materials were based on the modified DCPA compositions of calcium phosphate cement (CPC), where the phase ratio of the surface-modified DCPA is higher than that of the conventional CPC for forming dicalcium phosphate (DCP)-rich cement. The composition and morphology of several calcium phosphate cement specimens during setting were analyzed via X-ray diffractometry and transmission electron microscopy coupled with an energy dispersive spectroscopy system. The compressive strength of DCP-rich CPCs was greater than 30 MPa after 24 h of immersion in vitro. The reaction of the CPCs produced steady final biphasic products of DCPs with apatite. The composites of calcium phosphate cements derived from tetracalcium phosphate mixed with surface-modified DCPA exhibited excellent mechanical properties, injectability, and interlocking forces between particles, and they also featured nondispersive behavior when immersed in a physiological solution. - Highlights: • Bone cement precursor with nanocrystals is characterized. • DCP-rich CPCs with nanocrystals exhibited biphasic product phases. • Nanocrystals in cement significantly affected the interlocking ability. • Nanocrystals in cement exhibited higher strength and anti-dispersion. • DCP-rich CPCs increase the potential of bioresorption after reaction.

  8. Primary localized malignant biphasic mesothelioma of the liver in a patient with asbestosis

    Institute of Scientific and Technical Information of China (English)

    Motoko Sasaki; Ichiro Araki; Toshiaki Yasui; Masaru Kinoshita; Keita Itatsu; Takayuki Nojima; Yasuni Nakanuma

    2009-01-01

    We report a case of primary localized malignant biphasic mesothelioma of the liver in a 66-yearold man associated with asbestosis. The tumor was detected as a hepatic nodule, 4 cm in diameter, in the right lobe (S8 segment) on CT scan. Histopathological examination demonstrated an intrahepatic tumor with central necrosis consisting of a papillary epithelioid pattern on the surface of the liver, microcystic (microglandular or adenomatoid) pattern mainly in the subcapsular area and sarcomatoid pattern intermingled with microcystic pattern in the major part of the hepatic nodular tumor. Tumor cells, especially of epithelioid type, showed distinct immunoreactivity for mesothelial markers (WT-1, calretinin, D2-40, CK5/6,mesothelin, thrombomodulin) and no immunoreactivity for epithelial (adenocarcinoma) markers (CEA, CD15,BerEP4, BG8, MOC31). P53 immunoreactivity was detected focally in papillary epithelioid tumor cells and extensively in microcystic and sarcomatoid components, suggesting that the papillary epithelioid mesothelioma arose on the surface of the liver, and tumor cells showing microcystic and sarcomatoid patterns invaded and grew into the liver. To date, this is the first case of primary localized malignant biphasic mesothelioma of the liver, since all three primary hepatic mesotheliomas reported so far were epithelioid type.

  9. Method for separating water soluble organics from a process stream by aqueous biphasic extraction

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, D.J.; Mego, W.A.

    1999-09-07

    A method for separating water-miscible organic species from a process stream by aqueous biphasic extraction is provided. An aqueous biphase system is generated by contacting a process stream comprised of water, salt, and organic species with an aqueous polymer solution. The organic species transfer from the salt-rich phase to the polymer-rich phase, and the phases are separated. Next, the polymer is recovered from the loaded polymer phase by selectively extracting the polymer into an organic phase at an elevated temperature, while the organic species remain in a substantially salt-free aqueous solution. Alternatively, the polymer is recovered from the loaded polymer by a temperature induced phase separation (cloud point extraction), whereby the polymer and the organic species separate into two distinct solutions. The method for separating water-miscible organic species is applicable to the treatment of industrial wastewater streams, including the extraction and recovery of complexed metal ions from salt solutions, organic contaminants from mineral processing streams, and colorants from spent dye baths.

  10. Method for separating water soluble organics from a process stream by aqueous biphasic extraction

    Energy Technology Data Exchange (ETDEWEB)

    Chaiko, David J. (Naperville, IL); Mego, William A. (Naperville, IL)

    1999-01-01

    A method for separating water-miscible organic species from a process stream by aqueous biphasic extraction is provided. An aqueous biphase system is generated by contacting a process stream comprised of water, salt, and organic species with an aqueous polymer solution. The organic species transfer from the salt-rich phase to the polymer-rich phase, and the phases are separated. Next, the polymer is recovered from the loaded polymer phase by selectively extracting the polymer into an organic phase at an elevated temperature, while the organic species remain in a substantially salt-free aqueous solution. Alternatively, the polymer is recovered from the loaded polymer by a temperature induced phase separation (cloud point extraction), whereby the polymer and the organic species separate into two distinct solutions. The method for separating water-miscible organic species is applicable to the treatment of industrial wastewater streams, including the extraction and recovery of complexed metal ions from salt solutions, organic contaminants from mineral processing streams, and colorants from spent dye baths.

  11. Biphasic effects of ethanol and sodium oleate on synaptic transport of aspartic acid

    Energy Technology Data Exchange (ETDEWEB)

    Foley, T.; Rhoads, D.E.

    1987-05-01

    The authors have examined the effects of ethanol and sodium oleate on the transport of aspartic acid (ASP) by nerve-ending preparations from rat cerebral cortex. Physiologically relevant ethanol concentrations of up to 100mM stimulated ASP uptake while concentrations greater than 200mM caused inhibition. A similar biphasic effect was observed with oleate stimulating ASP uptake at 0.1 to 1..mu..M and inhibiting ASP uptake at concentrations greater than 1..mu..M. Maximum stimulation was observed at 0.1..mu..M oleate and at 50mM ethanol. In contrast, when synaptosomes were prepared from rats that had been exposed for 2-3 weeks to 10% ethanol in their drinking water, higher concentrations of ethanol and oleate were required to obtain comparable stimulation of ASP uptake. These biphasic effects on ASP transport can be interpreted in terms of physicochemical alterations in the synaptic membranes, with from alcohol-exposed rats showing tolerance to these fluidizing effects.

  12. Bi-phasic titanium dioxide nanoparticles doped with nitrogen and neodymium for enhanced photocatalysis.

    Science.gov (United States)

    Gomez, Virginia; Bear, Joseph C; McNaughter, Paul D; McGettrick, James D; Watson, Trystan; Charbonneau, Cecile; O'Brien, Paul; Barron, Andrew R; Dunnill, Charles W

    2015-11-14

    Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with "Janus-like" characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co-doped particles under white light.

  13. Fluid pressurization and tractional forces during TMJ disc loading: A biphasic finite element analysis.

    Science.gov (United States)

    Wu, Y; Cisewski, S E; Wei, F; She, X; Gonzales, T S; Iwasaki, L R; Nickel, J C; Yao, H

    2017-06-01

    To investigate the ploughing mechanism associated with tractional force formation on the temporomandibular joint (TMJ) disc surface. Ten left TMJ discs were harvested from 6- to 8-month-old male Yorkshire pigs. Confined compression tests characterized mechanical TMJ disc properties, which were incorporated into a biphasic finite element model (FEM). The FEM was established to investigate load carriage within the extracellular matrix (ECM) and the ploughing mechanism during tractional force formation by simulating previous in vitro plough experiments. Biphasic mechanical properties were determined in five TMJ disc regions (average±standard deviation for aggregate modulus: 0.077±0.040 MPa; hydraulic permeability: 0.88±0.37×10(-3) mm(4) /Ns). FE simulation results demonstrated that interstitial fluid pressurization is a dominant loading support mechanism in the TMJ disc. Increased contact load and duration led to increased solid ECM strain and stress within, and increased ploughing force on the surface of the disc. Sustained mechanical loading may play a role in load carriage within the ECM and ploughing force formation during stress-field translation at the condyle-disc interface. This study further elucidated the mechanism of ploughing on tractional force formation and provided a baseline for future analysis of TMJ mechanics, cartilage fatigue and early TMJ degeneration. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Superabsorbent biphasic system based on poly(lactic acid) and poly(acrylic acid)

    Science.gov (United States)

    Sartore, Luciana; Pandini, Stefano; Baldi, Francesco; Bignotti, Fabio

    2016-05-01

    In this research work, biocomposites based on crosslinked particles of poly(acrylic acid), commonly used as superabsorbent polymer (SAP), and poly-L-lactic acid (PLLA) were developed to elucidate the role of the filler (i.e., polymeric crosslinked particles) on the overall physico-mechanical behavior and to obtain superabsorbent thermoplastic products. Samples prepared by melt-blending of components in different ratios showed a biphasic system with a regular distribution of particles, with diameter ranging from 5 to 10 μm, within the PLLA polymeric matrix. The polymeric biphasic system, coded PLASA i.e. superabsorbent poly(lactic acid), showed excellent swelling properties, demonstrating that cross-linked particles retain their superabsorbent ability, as in their free counterparts, even if distributed in a thermoplastic polymeric matrix. The thermal characteristics of the biocomposites evidence enhanced thermal stability in comparison with neat PLLA and also mechanical properties are markedly modified by addition of crosslinked particles which induce regular stiffening effect. Furthermore, in aqueous environments the particles swell and are leached from PLLA matrix generating very high porosity. These new open-pore PLLA foams, produced in absence of organic solvents and chemical foaming agents, with good physico-mechanical properties appear very promising for several applications, for instance in tissue engineering for scaffold production.

  15. New resource for the computation of cartilage biphasic material properties with the interpolant response surface method.

    Science.gov (United States)

    Keenan, Kathryn E; Kourtis, Lampros C; Besier, Thor F; Lindsey, Derek P; Gold, Garry E; Delp, Scott L; Beaupre, Gary S

    2009-08-01

    Cartilage material properties are important for understanding joint function and diseases, but can be challenging to obtain. Three biphasic material properties (aggregate modulus, Poisson's ratio and permeability) can be determined using an analytical or finite element model combined with optimisation to find the material properties values that best reproduce an experimental creep curve. The purpose of this study was to develop an easy-to-use resource to determine biphasic cartilage material properties. A Cartilage Interpolant Response Surface was generated from interpolation of finite element simulations of creep indentation tests. Creep indentation tests were performed on five sites across a tibial plateau. A least-squares residual search of the Cartilage Interpolant Response Surface resulted in a best-fit curve for each experimental condition with corresponding material properties. These sites provided a representative range of aggregate moduli (0.48-1.58 MPa), Poisson's ratio (0.00-0.05) and permeability (1.7 x 10(- 15)-5.4 x 10(- 15) m(4)/N s) values found in human cartilage. The resource is freely available from https://simtk.org/home/va-squish.

  16. Influence of Biphasic Stimulation on Olfactory Ensheathing Cells for Neuroprosthetic Devices

    Directory of Open Access Journals (Sweden)

    Rachelle Therese Hassarati

    2016-10-01

    Full Text Available The recent success of olfactory ensheathing cell (OEC assisted regeneration of injured spinal cord has seen a rising interest in the use of these cells in tissue-engineered systems. Previously shown to support neural cell growth through glial scar tissue, OECs have the potential to assist neural network formation in living electrode systems to produce superior neuroprosthetic electrode surfaces. The following study sought to understand the influence of biphasic electrical stimulation (ES, inherent to bionic devices, on cell survival and function, with respect to conventional metallic and developmental conductive hydrogel (CH coated electrodes. The CH utilised in this study was a biosynthetic hydrogel consisting of methacrylated poly(vinyl-alcohol (PVA, heparin and gelatin through which poly(3,4-ethylenedioxythiophene (PEDOT was electropolymerised. OECs cultured on Pt and CH surfaces were subjected to biphasic ES. Image-based cytometry yielded little significant difference between the viability and cell cycle of OECs cultured on the stimulated and passive samples. The significantly lower voltages measured across the CH electrodes (147 ± 3 mV compared to the Pt (317 ± 5 mV, had shown to influence a higher percentage of viable cells on CH (91 - 93 % compared to Pt (78 - 81 %. To determine the functionality of these cells following electrical stimulation, OECs co-cultured with PC12 cells were found to support neural cell differentiation (an indirect measure of neurotrophic factor production following ES.

  17. Fabrication of nano structural biphasic materials from phosphogypsum waste and their in vitro applications

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, Khaled R., E-mail: Kh_rezk966@yahoo.com [Biomaterials Department, National Research Centre, Dokki, Cairo (Egypt); Mousa, Sahar M. [Chemistry Department, Science and Art College, King Abdulaziz University, Rabigh Campus, P.O. Box 344, 21911 Rabigh (Saudi Arabia); Inorganic Chemistry Department, National Research Centre, Dokki, P.O. Box 12622, 11787 Cairo (Egypt); El Bassyouni, Gehan T. [Biomaterials Department, National Research Centre, Dokki, Cairo (Egypt); Medical Physics Department, College of Medicine, Taif University (Saudi Arabia)

    2014-02-01

    Graphical abstract: (a) Schema of the process, (b) TEM of nano particles of biphasic materials and (c) SEM of post-immersion. - Highlights: • Ratio of HA and β-TCP phases were controlled by thermal treatment. • HA partially decomposed into β-TCP with other bioactive phases. • Calcined HA at 900 °C is the best for the bioactivity behavior. - Abstract: In this study, a novel process of preparing biphasic calcium phosphate (BCP) is proposed. Also its bioactivity for the utilization of the prepared BCP as a biomaterial is studied. A mixture of calcium hydroxyapatite (HAP) and tricalcium phosphate (β-TCP) could be obtained by thermal treatment of HAP which was previously prepared from phosphogypsum (PG) waste. The chemical and phase composition, morphology and particle size of prepared samples was characterized by X-ray diffraction (XRD), Infrared spectroscopy (IR), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The bioactivity was investigated by soaking of the calcined samples in simulated body fluid (SBF). Results confirmed that the calcination temperatures played an important role in the formation of calcium phosphate (CP) materials. XRD results indicated that HAP was partially decomposed into β-TCP. The in vitro data confirmed that the calcined HAP forming BCP besides other phases such as pyrophosphate and silica are bioactive materials. Therefore, BCP will be used as good biomaterials for medical applications.

  18. Efficient One-Pot Synthesis of 5-Chloromethylfurfural (CMF from Carbohydrates in Mild Biphasic Systems

    Directory of Open Access Journals (Sweden)

    Dimitris S. Argyropoulos

    2013-07-01

    Full Text Available 5-Halomethylfurfurals can be considered as platform chemicals of high reactivity making them useful for the preparation of a variety of important compounds. In this study, a one-pot route for the conversion of carbohydrates into 5-chloromethylfurfural (CMF in a simple and efficient (HCl-H3PO4/CHCl3 biphasic system has been investigated. Monosaccharides such as D-fructose, D-glucose and sorbose, disaccharides such as sucrose and cellobiose and polysaccharides such as cellulose were successfully converted into CMF in satisfactory yields under mild conditions. Our data shows that when using D-fructose the optimum yield of CMF was about 47%. This understanding allowed us to extent our work to biomaterials, such as wood powder and wood pulps with yields of CMF obtained being comparable to those seen with some of the enumerated mono and disaccharides. Overall, the proposed (HCl-H3PO4/CHCl3 optimized biphasic system provides a simple, mild, and cost-effective means to prepare CMF from renewable resources.

  19. Investigation of biphasic tumor oxygen dynamics induced by hyperoxic gas intervention: the dynamic phantom approach

    Science.gov (United States)

    Kim, Jae G.; Liu, Hanli

    2008-01-01

    We have developed dynamic tumor vascular phantoms and utilized them to investigate the biphasic behavior of increases in light absorption, which is directly associated with oxygenated hemoglobin concentration that was observed in vivo from rat breast tumor experiments during carbogen/oxygen inhalation. The experimental setup for the phantom study included a continuous-wave, multichannel, near-infrared spectroscopy (NIRS) system and syringe pumps to drive the simulated blood through the dynamic vascular phantoms. The results from such phantom experiments clearly show that the two time constants observed in tumor oxygenation dynamics in vivo can result from two different perfusion rates or two different blood flow velocities. We provide experimental support for our previous hypothesis: the biphasic tumor hemodynamic feature stems from a well-perfused and poorly perfused region that could be detected with the two time constants of the NIRS signals. With a multichannel approach, noninvasive NIRS measurements may have useful and prognostic values to quantify the therapeutic effects of cancer treatments.

  20. A Physicochemically Optimized and Neuroconductive Biphasic Nerve Guidance Conduit for Peripheral Nerve Repair.

    Science.gov (United States)

    Ryan, Alan J; Lackington, William A; Hibbitts, Alan J; Matheson, Austyn; Alekseeva, Tijna; Stejskalova, Anna; Roche, Phoebe; O'Brien, Fergal J

    2017-10-04

    Clinically available hollow nerve guidance conduits (NGCs) have had limited success in treating large peripheral nerve injuries. This study aims to develop a biphasic NGC combining a physicochemically optimized collagen outer conduit to bridge the transected nerve, and a neuroconductive hyaluronic acid-based luminal filler to support regeneration. The outer conduit is mechanically optimized by manipulating crosslinking and collagen density, allowing the engineering of a high wall permeability to mitigate the risk of neuroma formation, while also maintaining physiologically relevant stiffness and enzymatic degradation tuned to coincide with regeneration rates. Freeze-drying is used to seamlessly integrate the luminal filler into the conduit, creating a longitudinally aligned pore microarchitecture. The luminal stiffness is modulated to support Schwann cells, with laminin incorporation further enhancing bioactivity by improving cell attachment and metabolic activity. Additionally, this biphasic NGC is shown to support neurogenesis and gliogenesis of neural progenitor cells and axonal outgrowth from dorsal root ganglia. These findings highlight the paradigm that a successful NGC requires the concerted optimization of both a mechanical support phase capable of bridging a nerve defect and a neuroconductive phase with an architecture capable of supporting both Schwann cells and neurons in order to achieve functional regenerative outcome. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Biphasic recruitment of microchimeric fetal mesenchymal cells in fibrosis following acute kidney injury.

    Science.gov (United States)

    Roy, Edwige; Seppanen, Elke; Ellis, Rebecca; Lee, Eddy S; Khosrotehrani, Kiarash; Khosroterani, Kiarash; Fisk, Nicholas M; Bou-Gharios, George

    2014-03-01

    Fetal microchimeric cells (FMCs) enter the maternal circulation and persist in tissue for decades. They have capacity to home to injured maternal tissue and differentiate along that tissue's lineage. This raises the question of the origin(s) of cells transferred to the mother during pregnancy. FMCs with a mesenchymal phenotype have been documented in several studies, which makes mesenchymal stem cells an attractive explanation for their broad plasticity. Here we assessed the recruitment and mesenchymal lineage contribution of FMCs in response to acute kidney fibrosis induced by aristolochic acid injection. Serial in vivo bioluminescence imaging revealed a biphasic recruitment of active collagen-producing FMCs during the repair process of injured kidney in post-partum wild-type mothers that had delivered transgenic pups expressing luciferase under the collagen type I-promoter. The presence of FMCs long-term post injury (day 60) was associated with profibrotic molecules (TGF-β/CTGF), serum urea levels, and collagen deposition. Immunostaining confirmed FMCs at short term (day 15) using post-partum wild-type mothers that had delivered green fluorescent protein-positive pups and suggested a mainly hematopoietic phenotype. We conclude that there is biphasic recruitment to, and activity of, FMCs at the injury site. Moreover, we identified five types of FMC, implicating them all in the reparative process at different stages of induced renal interstitial fibrosis.

  2. Isoattenuating insulinomas at biphasic contrast-enhanced CT: frequency, clinicopathologic features and perfusion characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Liang; Xue, Hua-dan; Sun, Hao; Wang, Xuan; He, Yong-lan; Jin, Zheng-yu [Peking Union Medical College Hospital, Department of Radiology, Beijing (China); Zhao, Yu-pei [Peking Union Medical College Hospital, Department of General Surgery, Beijing (China)

    2016-10-15

    We aimed to determine the frequency of isoattenuating insulinomas, to investigate their clinicopathological features and to assess their regional pancreatic perfusion characteristics. Institutional review board approval was obtained, and patient informed consent was waived. From July 2010 to June 2014, 170 patients (66 male, 104 female) with endogenous hyperinsulinemic hypoglycemia underwent biphasic contrast-enhanced CT before surgery, and 129 of those patients also received preoperative whole-pancreas CT perfusion. A total of 181 tumours were proved histopathologically after surgery. Enhancement pattern and regional pancreatic perfusion characteristics were analyzed. Clinical features, tumour size and pathological grading were investigated. The frequency of isoattenuating tumours was 24.9 %. Tumour size and WHO grading was not significantly different between isoattenuating and hyperattenuating tumours. Tumour-free regions had identical blood flow (BF) regardless of their location (p = 0.35). Isoattenuating tumour-harbouring regions had lower BF compared with hyperattenuating tumour-harbouring regions; both showed higher BF compared with tumour-free neighbourhood regions (all p < 0.01). For patients with isoattenuating tumours, the overall hospital stay was longer (p < 0.01). A substantial subset of insulinomas were isoattenuating on biphasic CT. CT perfusion showed higher BF in tumour-harbouring regions compared to tumour-free regions, providing a clue for tumour regionalization. (orig.)

  3. Influence of Biphasic Stimulation on Olfactory Ensheathing Cells for Neuroprosthetic Devices

    Science.gov (United States)

    Hassarati, Rachelle T.; Foster, L. John R.; Green, Rylie A.

    2016-01-01

    The recent success of olfactory ensheathing cell (OEC) assisted regeneration of injured spinal cord has seen a rising interest in the use of these cells in tissue-engineered systems. Previously shown to support neural cell growth through glial scar tissue, OECs have the potential to assist neural network formation in living electrode systems to produce superior neuroprosthetic electrode surfaces. The following study sought to understand the influence of biphasic electrical stimulation (ES), inherent to bionic devices, on cell survival and function, with respect to conventional metallic and developmental conductive hydrogel (CH) coated electrodes. The CH utilized in this study was a biosynthetic hydrogel consisting of methacrylated poly(vinyl-alcohol) (PVA), heparin and gelatin through which poly(3,4-ethylenedioxythiophene) (PEDOT) was electropolymerised. OECs cultured on Pt and CH surfaces were subjected to biphasic ES. Image-based cytometry yielded little significant difference between the viability and cell cycle of OECs cultured on the stimulated and passive samples. The significantly lower voltages measured across the CH electrodes (147 ± 3 mV) compared to the Pt (317 ± 5 mV), had shown to influence a higher percentage of viable cells on CH (91–93%) compared to Pt (78–81%). To determine the functionality of these cells following electrical stimulation, OECs co-cultured with PC12 cells were found to support neural cell differentiation (an indirect measure of neurotrophic factor production) following ES. PMID:27757072

  4. Time-dependent biphasic modulation of human BDNF by antidepressants in neuroblastoma cells

    Directory of Open Access Journals (Sweden)

    Musazzi Laura

    2008-07-01

    Full Text Available Abstract Background Recent rodent studies reported that antidepressant treatments affect the expression of brain-derived neurotrophic factor (BDNF mRNA in a way that is dependent on treatment duration, by selective modulation of different BDNF transcripts. However, no data are available for the human BDNF gene. We studied the effect of different antidepressants on BDNF mRNA expression in human neuroblastoma SH-SY5Y cells. Results Cultured cells were treated with the antidepressants fluoxetine, reboxetine and desipramine for different time lengths (6, 24, 48 hours. Expression of total BDNF mRNA was analyzed by reverse transcription PCR and levels of different BDNF transcripts were detected by hemi-nested PCR with specific primers. Short-term treatment (6 hours with reboxetine or desipramine reduced total BDNF, whereas long-term treatment (48 hours significantly increased total BDNF mRNA levels. These changes were accounted for by differential regulation of BDNF IV and VIa/b transcripts. Fluoxetine showed no significant effects. Conclusion This is the first study showing biphasic changes in the expression of total and specific BDNF transcripts in human cells following antidepressant treatments. These findings suggest that biphasic induction of BDNF by antidepressants could be a feature common to rodents and humans and encourage the use of SH-SY5Y cells as a tool for investigation of drug effects on human genes.

  5. A New Explicit Algorithm for Bi-Phasic Mixture Flow in MIM

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Metal injection moulding (MIM) is a new technology to manufacture small intricate parts in large quantity. Numerical simulation plays an important role in its development. To predict the specific segregation effect in MIM injection, mixture theory is adopted to model the injection flow by a bi-phasic model. This model conducts to the solution of two-coupled Stokes equations. It is an extremely computational consuming solution in the scope of the traditional algorithms, which induce a serious challenge to cost-effectivity of the MIM simulation. Referred to some methods proposed by Lewis in mono-phasic simulation and the implicit algorithms in MIM simulation, a new explicit algorithm is proposed and realized to perform efficiently this type of bi-phasic flow. Numerically this algorithm is devised to perform the simulation in a fully uncoupled manner except for a global solution of the pressure field in each time step. The physical coupling is taken into account in a sequential pattern by fractional steps. This special algorithm does not need any iteration, so it is straightforward and robust, suitable for MIM simulation and other sorts of simulations for multi-phasic flow.

  6. Implants in adolescents.

    Science.gov (United States)

    Shah, Rohit A; Mitra, Dipika K; Rodrigues, Silvia V; Pathare, Pragalbha N; Podar, Rajesh S; Vijayakar, Harshad N

    2013-07-01

    Implants have gained tremendous popularity as a treatment modality for replacement of missing teeth in adults. There is extensive research present on the use of implants in adults, but there is a dearth of data available on the same in adolescents. The treatment planning and execution of implant placement in adolescents is still in its infancy. This review article is an attempt to bring together available literature.

  7. Implants in adolescents

    Directory of Open Access Journals (Sweden)

    Rohit A Shah

    2013-01-01

    Full Text Available Implants have gained tremendous popularity as a treatment modality for replacement of missing teeth in adults. There is extensive research present on the use of implants in adults, but there is a dearth of data available on the same in adolescents. The treatment planning and execution of implant placement in adolescents is still in its infancy. This review article is an attempt to bring together available literature.

  8. Implant treatment planning considerations.

    Science.gov (United States)

    Kao, Richard T

    2008-04-01

    As dental implants become a more accepted treatment modality, there is a need for all parties involved with implant dentistry to be familiar with various treatment planning issues. Though the success can be highly rewarding, failure to forecast treatment planning issues can result in an increase of surgical needs, surgical cost, and even case failure. In this issue, the focus is on implant treatment planning considerations.

  9. Mechanism-based pharmacokinetic-pharmacodynamic modeling of concentration-dependent hysteresis and biphasic electroencephalogram effects of alphaxalone in rats.

    Science.gov (United States)

    Visser, S A G; Smulders, C J G M; Reijers, B P R; Van der Graaf, P H; Peletier, L A; Danhof, M

    2002-09-01

    The neuroactive steroid alphaxalone reveals a complex biphasic concentration-effect relationship using the 11.5 to 30 Hz frequency band of the electroencephalogram (EEG) as biomarker. The purpose of the present investigation was to develop a mechanism-based pharmacokinetic-pharmacodynamic model to describe this observation. The proposed model is based on receptor theory and aims to separate the drug-receptor interaction from the transduction of the initial stimulus into the observed biphasic response. Individual concentration-time courses of alphaxalone were obtained in combination with continuous recording of the EEG parameter. Alphaxalone was administered intravenously in various dosages. The pharmacokinetics were described by a two-compartment model, and parameter estimates for clearance, intercompartmental clearance, volume of distribution 1 and 2 were 158 +/- 29 ml. min(-1). kg(-1), 143 +/- 31 ml. min(-1). kg(-1), 122 +/- 20 ml. kg(-1) and 606 +/- 48 ml. kg(-1), respectively. Concentration-effect relationships exhibited a biphasic pattern and delay in onset of effect. The hysteresis was described on the basis of an effect-compartment model with C(max) as covariate. The pharmacodynamic model consisted of a receptor model, featuring a monophasic saturable receptor activation model in combination with a biphasic stimulus-response model. The in vivo affinity (K(PD)) was estimated at 432 +/- 26 ng. ml(-1). Unique parameter estimates were obtained that were independent of the dose and the duration of the infusion. In conclusion, we have shown that this mechanism-based approach, which separates drug- and system-related properties in vivo, was successfully applied for the characterization of the biphasic effect versus time patterns of alphaxalone. The model should be of use in the characterization of other biphasic responses.

  10. Indirect MR-arthography in the fellow up of autologous osteochondral transplantation; Indirekte MR-Arthrographie zur Verlaufskontrolle nach autologer osteochondraler Transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Herber, S.; Pitton, M.B.; Kalden, P.; Thelen, M.; Kreitner, K.F. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Runkel, M. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Unfallchirurgie

    2003-02-01

    Purpose: To evaluate the spectrum of findings in indirect MR-arthrography following autologous osteochondral transplantation. Patients and Methods: 10 patients with autogenous osteochondral homografts underwent indirect MR-arthrography at three, 6 and 12 months postoperatively. The MR protocol at 1.5T comprised unenhanced imagings with PD- and T{sub 2}-weighted TSE-sequences with and without fat-suppression as well as T{sub 1}-weighted fat-suppressed SE-sequences before and after iv. contrast administration and after active joint exercise. Image analysis was done by two radiologists in conference and comprised the evaluation of signal intensity (SI) and integrity of the osseous plug and the cartilage surface, as well as the presence of joint effusion or bone marrow edema. Results: At three months, all cases demonstrated a significant bone marrow edema at the recipient and donor site that corresponded to a significant enhancement after iv. contrast administration. The interface between the transplant and the normal bone showed an increased SI at three and 6 months in T{sub 2}-weighted images as well as in indirect MR-arthrography. The marrow signal normalized in most cases after 6 to 12 months, indicating vitality and healing of the transplanted osteochondral graft. The SI of the interface decreased in the same period, demonstrating the stability of the homograft at the recipient site. The osteochondral plugs were well-seated in 9/10 cases. Indirect MR-arthrography was superior to unenhanced imaging in the assessment of the cartilage surface. Cartilage coverage was complete in every case. The transplanted hyaline cartilage as well as the original cartilage showed a significant increase of the SI in indirect MR-arthrography, that did not change in follow up studies. There were no pathological alterations of signal and thickness alterations of the transplanted cartilage in follow up investigations. Conclusion: Indirect MR-arthrography is a useful diagnostic tool

  11. HA-Coated Implant

    DEFF Research Database (Denmark)

    Daugaard, Henrik; Søballe, Kjeld; Bechtold, Joan E

    2014-01-01

    The goal of osseointegration of orthopedic and dental implants is the rapid achievement of a mechanically stable and long lasting fixation between living bone and the implant surface. In total joint replacements of cementless designs, coatings of calcium phosphates were introduced as a means...... of improving the fixation of implants. Of these, hydroxyapatite (HA) is the most widely used and most extensively investigated. HA is highly osseoconductive, and the positive effect is well documented in both basic and long-term clinical research [1–6]. This chapter describes experimental and clinical studies...... evaluating bone-implant fixation with HA coatings....

  12. Ion implantation technology

    CERN Document Server

    Downey, DF; Jones, KS; Ryding, G

    1993-01-01

    Ion implantation technology has made a major contribution to the dramatic advances in integrated circuit technology since the early 1970's. The ever-present need for accurate models in ion implanted species will become absolutely vital in the future due to shrinking feature sizes. Successful wide application of ion implantation, as well as exploitation of newly identified opportunities, will require the development of comprehensive implant models. The 141 papers (including 24 invited papers) in this volume address the most recent developments in this field. New structures and possible approach

  13. Management of peri-implantitis

    OpenAIRE

    Jayachandran Prathapachandran; Neethu Suresh

    2012-01-01

    Peri-implantitis is a site-specific infectious disease that causes an inflammatory process in soft tissues, and bone loss around an osseointegrated implant in function. The etiology of the implant infection is conditioned by the status of the tissue surrounding the implant, implant design, degree of roughness, external morphology, and excessive mechanical load. The microorganisms most commonly associated with implant failure are spirochetes and mobile forms of Gram-negative anaerobes, unless ...

  14. Management of peri-implantitis

    OpenAIRE

    Jayachandran Prathapachandran; Neethu Suresh

    2012-01-01

    Peri-implantitis is a site-specific infectious disease that causes an inflammatory process in soft tissues, and bone loss around an osseointegrated implant in function. The etiology of the implant infection is conditioned by the status of the tissue surrounding the implant, implant design, degree of roughness, external morphology, and excessive mechanical load. The microorganisms most commonly associated with implant failure are spirochetes and mobile forms of Gram-negative anaerobes, unless ...

  15. Delayed breast implant reconstruction

    DEFF Research Database (Denmark)

    Hvilsom, Gitte B.; Hölmich, Lisbet R.; Steding-Jessen, Marianne;

    2012-01-01

    We evaluated the association between radiation therapy and severe capsular contracture or reoperation after 717 delayed breast implant reconstruction procedures (288 1- and 429 2-stage procedures) identified in the prospective database of the Danish Registry for Plastic Surgery of the Breast during...... reconstruction approaches other than implants should be seriously considered among women who have received radiation therapy....

  16. Ion Implantation of Polymers

    DEFF Research Database (Denmark)

    Popok, Vladimir

    2012-01-01

    are discussed. Related to that, the effects of radiothermolysis, degassing and carbonisation are considered. Specificity of depth distributions of implanted into polymers impurities is analysed and the case of high-fluence implantation is emphasised. Within rather broad topic of ion bombardment, the focus...

  17. Bi-phasic titanium dioxide nanoparticles doped with nitrogen and neodymium for enhanced photocatalysis

    Science.gov (United States)

    Gomez, Virginia; Bear, Joseph C.; McNaughter, Paul D.; McGettrick, James D.; Watson, Trystan; Charbonneau, Cecile; O'Brien, Paul; Barron, Andrew R.; Dunnill, Charles W.

    2015-10-01

    Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with ``Janus-like'' characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co-doped particles under white light.Bi-phasic or multi-phasic composite nanoparticles for use in photocatalysis have been produced by a new synthetic approach. Sol-gel methods are used to deposit multiple layers of active material onto soluble substrates. In this work, a layer of rutile (TiO2) was deposited onto sodium chloride pellets followed by an annealing step and a layer of anatase. After dissolving the substrate, bi-phasic nanoparticles containing half anatase and half rutile TiO2; with ``Janus-like'' characteristics are obtained. Nitrogen and neodymium doping of the materials were observed to enhance the photocatalytic properties both under UV and white light irradiation. The unique advantage of this synthetic method is the ability to systematically dope separate sides of the nanoparticles. Nitrogen doping was found to be most effective on the anatase side of the nanoparticle while neodymium was found to be most effective on the rutile side. Rhodamine B dye was effectively photodegraded by co

  18. P-glycoprotein regulating biphasic insulin secretion in rat pancreatic beta cells

    Institute of Scientific and Technical Information of China (English)

    TANG Yun-zhao; LI Dai-qing; SUN Fu-jun; LI Li; YU De-min

    2009-01-01

    Background A 65-kD mdr1(multi-drug resistance protein 1,P-glycoprotein)-like protein has been suggested to be the regulatory protein to the chloride channel protein 3(CIC-3)mediating insulin granules acidification and release in mouse pancreatic beta cells.But the protein has not been deeply investigated.In this study,we identified existence of the 65-kda protein in rat islets and preliminarily explored its biological functions.Methods Total RNAs of rat kidneys served as positive controls,and pancreas,islets and INS-1 cells were extracted for reverse-transcript PCR(RT-PCR),respectively.The cDNAs were run with specific primers selected from the mRNA of abcblb encoding P-glycoprotein.All PCR products were visualized in agarose gel electrophoresis and sequenced.Homogenates of rat islets and INS-1 cells were applied to SDS-PAGE.P-glycoprotein was detected by a specific monoclonal antibody,C219.Biphasic insulin release was measured in static incubations of rat islets with radioimmunology assay.Results Compared with positive control,expression of the P-glycoprotein mRNA segments were detected in the islets,INS-1 cells and pancreas.Sequence analysis confirmed that the PCR products were matched with mRNA of P-glycoprotein.A 65-kda protein was recognized by the antibody in the islets homogenate but not in that of INS-1 cells in Western-blotting.Instead,the homogenate of INS-1 cells contained a 160-kda protein recognized by the antibody.Insulin secretion of rat islets were stimulated by high glucose(16.7mmol/L),and showed biphasic curve during 60-minute incubation.After co-incubation with cyclosporine A(CsA),specific inhibitor to P-glycoprotein,the second phase of insulin secretion was reduced significantly while the first phase was not influenced.Conclusions The 65-kda protein expressed in rat islets is most likely a mini-P-glycoprotein.It may play a key role regulating biphasic insulin release.

  19. Temperature dependence of microwave absorption phenomena in single and biphase soft magnetic microwires

    Energy Technology Data Exchange (ETDEWEB)

    El Kammouni, Rhimou, E-mail: elkammounirhimou@gmail.com [Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid (Spain); Vázquez, Manuel [Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid (Spain); Lezama, Luis [Depto. Química Inorgánica, Universidad País Vasco, UPV/EHU, Bilbao (Spain); Kurlyandskaya, Galina [Depto. Electricidad y Electrónica, Universidad País Vasco, UPV/EHU, Bilbao (Spain); Dept. Magnetism and Magnetic Nanomaterials, Ural Federal University, Ekaterinburg (Russian Federation); Kraus, Ludek [Institute of Physics, Academy of Sciences of the Czech Republic, Prague (Czech Republic)

    2014-11-15

    The microwave absorption phenomena of single and biphase magnetic microwires with soft magnetic behavior have been investigated as a function of DC applied magnetic field using two alternative techniques: (i) absorption measurements in the temperature range of 4–300 K using a spectrometer operating at X-band frequency, at 9.5 GHz, and (ii) room-temperature, RT, ferromagnetic resonance measurements in a network analyzer in the frequency range up to 20 GHz. Complementary low-frequency magnetic characterization was performed in a Vibrating Sample Magnetometer. Studies have been performed for 8 μm diameter small-magnetostriction amorphous CoFeSiB single-phase microwire, coated by micrometric Pyrex layer, and after electroplating an external shell, 2 µm or 4 µm thick, of FeNi alloys. For single phase CoFeSiB microwire, a single absorption is observed, whose DC field dependence of resonance frequency at RT fits to a Kittel-law behavior for in-plane magnetized thin film. The temperature dependence behavior shows a monotonic increase in the resonance field, H{sub r}, with temperature. A parallel reduction of the circular anisotropy field, H{sub K}, is deduced from the temperature dependence of hysteresis loops. For biphase, CoFeSiB/FeNi, microwires, the absorption phenomena at RT also follow the Kittel condition. The observed opposite evolution with temperature of resonance field, H{sub r}, in 2 and 4 µm thick FeNi samples is interpreted considering the opposite sign of magnetostriction of the respective FeNi layers. The stress-induced magnetic anisotropy field, H{sub K}, in the FeNi shell is deduced to change sign at around 130 K. - Highlights: • A single absorption phenomenon is observed for single phase CoFeSiB. • The T dependence of the microwave behavior shows a monotonic increase of H{sub r} with T. • The absorption at RT follows the Kittel condition for biphase CoFe/FeNi microwires. • The T dependence of resonant field of CoFe/FeNi is interpreted to be

  20. Osteochondritis dissecans of the capitellum: lesion size and pattern analysis using quantitative 3-dimensional computed tomography and mapping technique.

    Science.gov (United States)

    Bexkens, Rens; Oosterhoff, Jacobien H; Tsai, Tsung-Yuan; Doornberg, Job N; van den Bekerom, Michel P J; Eygendaal, Denise; Oh, Luke S

    2017-09-01

    The goals of this study were to evaluate the reliability of a quantitative 3-dimensional computed tomography (Q3DCT) technique for measurement of the capitellar osteochondritis dissecans (OCD) surface area, to analyze OCD distribution using a mapping technique, and to investigate associations between Q3DCT lesion quantification and demographic characteristics and/or clinical examination findings. We identified patients with capitellar OCD who presented to our orthopedic sports medicine practice between January 2001 and January 2016 and who had undergone a preoperative computed tomography scan (slice thickness ≤1.25 mm). A total of 17 patients with a median age of 15 years (range, 12-23 years) were included in this study. Three-dimensional polygon models were reconstructed after osseous structures were marked in 3 planes. Surface areas of the OCD lesion as well as the capitellum were measured. Observer agreement was assessed with the intraclass correlation coefficient (ICC). Heat maps were created to visualize OCD distribution. Measurements of the OCD surface area showed almost perfect intraobserver agreement (ICC, 0.99; confidence interval [CI], 0.98-0.99) and interobserver agreement (ICC, 0.93; CI, 0.86-0.97). Measurements of the capitellar surface area also showed almost perfect intraobserver agreement (ICC, 0.97;CI, 0.91-0.99) and interobserver agreement (ICC, 0.86; CI, 0.46-0.96). The median OCD surface area was 101 mm(2) (range, 49-217 mm(2)). On the basis of OCD heat mapping, the posterolateral zone of the capitellum was most frequently affected. OCDs in which the lateral wall was involved were associated with larger lesion size (P = .041), longer duration of symptoms (P = .030), and worse elbow extension (P = .013). The ability to quantify the capitellar OCD surface area and lesion location in a reliable manner using Q3DCT and a mapping technique should be considered when detailed knowledge of lesion size and location is desired

  1. MUSIC AND COCHLEAR IMPLANTS

    Institute of Scientific and Technical Information of China (English)

    Mao Yitao; Xu Li

    2013-01-01

    Currently, most people with modern multichannel cochlear implant systems can understand speech in qui-et environment very well. However, studies in recent decades reported a lack of satisfaction in music percep-tion with cochlear implants. This article reviews the literature on music ability of cochlear implant users by presenting a systematic outline of the capabilities and limitations of cochlear implant recipients with regard to their music perception as well as production. The review also evaluates the similarities and differences be-tween electric hearing and acoustic hearing regarding music perception. We summarize the research results in terms of the individual components of music (e.g., rhythm, pitch, and timbre). Finally, we briefly intro-duce the vocal singing of prelingually-deafened children with cochlear implants as evaluated by acoustic measures.

  2. 跖骨Jacoby截骨术治疗早期跖骨头骨软骨病%Jacoby osteotomy for early-stage osteochondritis of metatarsal head

    Institute of Scientific and Technical Information of China (English)

    陈兆军; 吴俊德; 祁印泽; 马玉峰; 马占华; 李昕宇; 王正义

    2015-01-01

    背景:跖骨头骨软骨病,又称跖骨头骨坏死,对于跖骨头关节面出现塌陷的晚期患者目前大都主张手术治疗,早期患者主张保守治疗.但对于疼痛严重的早期患者的治疗则存在争议.目的:探讨Jacoby截骨术治疗早期跖骨头骨软骨病的临床疗效,从而为临床上更加合理有效地治疗跖骨头骨软骨病提供方法和依据.方法:2008年6月至2014年9月,我院采用Jacoby截骨术治疗早期跖骨头骨软骨病患者25例,其中18例(21足)临床资料完整并获随访.女14例(17足),男4例(4足);年龄29~58岁,平均36.3岁.单侧15例,双侧3例;病变发生于第2跖骨头15足,第3跖骨头5足,第4跖骨头处1足;合并 外翻畸形16足,趾间神经瘤或神经卡压5足.所有患者均有相应足趾处疼痛,且病史1年以上.负重位X线片依据Smillie分期:Ⅱ期13足,Ⅲ期8足.测量并记录术前、术后跖趾关节背伸、跖屈角度.根据美国足踝外科协会Maryland跖趾关节百分评分法对术后足部功能改善情况进行评定.结果:随访时间14~72个月,平均38.4个月.术后患者跖趾关节处疼痛消失,活动自如,术前跖趾关节活动度:背伸30.6°±1.87°,跖屈34.3°±2.96°;术后:背伸32.9°±1.67°,跖屈36.7°±1.17°,术后与术前跖趾关节活动度比较,差异无统计学意义(P>0.05).Maryland评分:优16足(76.2%),良5足(23.8%).结论:对于年轻且处于Smillie分期早期的跖骨头骨软骨病患者,Jacoby截骨术可取得满意、确切的治疗效果,并且手术操作简单,截骨处稳定,仅用1枚螺钉固定即可.%Background:Osteochondritis of the metatarsal head is also named as metatarsal head necrosis. It is suggested that the late-stage osteochondritis of metatarsal head should be treated by surgery, while the early-stage one usually be treated by a con-servative therapy. However, the treatment for early-stage osteochondritis of metatarsal head in which severe pain recurs is in dispute. Objective

  3. Biphasic contrast medium injection in cardiac CT: moderate versus high concentration contrast material at identical iodine flux and iodine dose.

    NARCIS (Netherlands)

    Rutten, A.; Meijs, M.F.; Vos, A.M.C.; Seidensticker, P.R.; Prokop, M.

    2010-01-01

    OBJECTIVE: To prospectively investigate the influence of contrast material concentration on enhancement in cardiac CT by using a biphasic single-injection protocol. METHODS: Sixty-four-row multidetector cardiac CT angiography was performed in 159 patients randomised to a moderate or high contrast me

  4. Role of apparent pKa of carboxylic acids in lipase-catalyzed esterifications in biphasic systems

    NARCIS (Netherlands)

    Dominguez de Maria, Pablo; Fernandez-Alvaro, Elena; Kate, ten Antoon; Bargeman, Gerrald

    2009-01-01

    Lipase-catalyzed esterifications in biphasic media (heptane–water, 1:1) were conducted by using Thermomyces lanuginosus lipase (TLL) as biocatalyst. Different carboxylic acids (from acetic to lauric) were thus esterified with 1-butanol at different pH values (2–10). For all carboxylic acids tested,

  5. Kinetic studies on the Rhizomucor miehei lipase catalyzed esterification reaction of oleic acid with 1-butanol in a biphasic system

    NARCIS (Netherlands)

    Kraai, G.N.; Winkelman, J.G.M.; de Vries, Johannes; Heeres, H.J.

    2008-01-01

    The kinetics of the esterification of oleic acid with 1 -butanol catalyzed by free Rhizomucor miehei lipase in a biphasic system was studied in a batch reactor. The reaction appeared to proceed via a Ping Pong bi-bi mechanism with I -butanol inhibition. The kinetic constants of the model were

  6. Kinetic studies on the Rhizomucor miehei lipase catalyzed esterification reaction of oleic acid with 1-butanol in a biphasic system

    NARCIS (Netherlands)

    Kraai, G.N.; Winkelman, J.G.M.; de Vries, Johannes; Heeres, H.J.

    2008-01-01

    The kinetics of the esterification of oleic acid with 1 -butanol catalyzed by free Rhizomucor miehei lipase in a biphasic system was studied in a batch reactor. The reaction appeared to proceed via a Ping Pong bi-bi mechanism with I -butanol inhibition. The kinetic constants of the model were determ

  7. Application of the e-KT-UNIFAC Model for the Improved and Innovative Design of Biphasic Reacting Systems

    DEFF Research Database (Denmark)

    Anantpinijwatna, Amata; Kim, Sun H.; Sales-Cruz, Mauricio

    2016-01-01

    Biphasic reacting systems contain effectively immiscible aqueous and organic liquid phases in which reactants, products, and catalysts can partition. These conditions allow novel synthesis paths, higher yields, and faster reactions, as well as facilitate product(s) separation. A systematic modeli...... of epoxidation of palm oil and production of furan derivatives....

  8. INVESTIGATION OF AQUEOUS BIPHASIC SYSTEMS FOR THE SEPARATIONS OF LIGNINS FROM CELLULOSE IN THE PAPER PULPING PROCESS. (R826732)

    Science.gov (United States)

    In efforts to apply a polymer-based aqueous biphasic system (ABS) extraction to the paper pulping process, the study of the distribution of various lignin and cellulosic fractions in ABS and the effects of temperature on system composition and solute partitioning have been inv...

  9. (R)-PAC biosynthesis in [BMIM][PF₆]/aqueous biphasic system using Saccharomyces cerevisiae BY4741 cells.

    Science.gov (United States)

    Kandar, Smita; Suresh, A K; Noronha, Santosh B

    2015-02-01

    (R)-phenylacetylcarbinol or (R)-PAC is a pharmaceutical precursor of (1R, 2S) ephedrine and (1S, 2S) pseudoephedrine. Biotransformation of benzaldehyde and glucose by pyruvate decarboxylase produces (R)-PAC. This biotransformation suffers from toxicity of the substrate, product [(R)-PAC] and by-product (benzyl alcohol). In the present study, ionic liquid/aqueous biphasic system was employed to enhance (R)-PAC production. Fermented broth was the reaction medium in which Saccharomyces cerevisiae BY4741 was the source of pyruvate decarboxylase. Hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) was the non-aqueous phase in which toxic compounds reside. Biocompatibility of [BMIM][PF6] and adequate distribution coefficients of benzaldehyde, (R)-PAC and benzyl alcohol were determined. A Box-Behnken design and response surface methodology were used for the optimization of biotransformation variables in order to maximize (R)-PAC yield and productivity. The results showed higher (R)-PAC yield and productivity of ∼1.5-fold each in the biphasic biotransformation of phase volume ratio 0.05 as compared to the monophasic (conventional) biotransformation. Moreover, the level of major by-product benzyl alcohol was also 3.5-fold lower in biphasic biotransformation. [BMIM][PF6]/aqueous biphasic system is a new approach which could intensify the (R)-PAC production.

  10. Induction of bone formation by smart biphasic hydroxyapatite tricalcium phosphate biomimetic matrices in the non-human primate Papio ursinus

    CSIR Research Space (South Africa)

    Ripamonti, U

    2008-01-01

    Full Text Available Long-term studies in the non-human primate Chacma baboon Papio ursinus were set to investigate the induction of bone formation by biphasic hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) biomimetic matrices. HA/β-TCP biomimetic matrices in a pre...

  11. Benefits and Risks of Cochlear Implants

    Science.gov (United States)

    ... Prosthetics Cochlear Implants Benefits and Risks of Cochlear Implants Share Tweet Linkedin Pin it More sharing options ... Cochlear Implants What are the Benefits of Cochlear Implants? For people with implants: Hearing ranges from near ...

  12. A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed-bed microreactor

    Directory of Open Access Journals (Sweden)

    Andrew Bogdan

    2009-04-01

    Full Text Available We demonstrate the preparation and characterization of a simplified packed-bed microreactor using an immobilized TEMPO catalyst shown to oxidize primary and secondary alcohols via the biphasic Anelli-Montanari protocol. Oxidations occurred in high yields with great stability over time. We observed that plugs of aqueous oxidant and organic alcohol entered the reactor as plugs but merged into an emulsion on the packed-bed. The emulsion coalesced into larger plugs upon exiting the reactor, leaving the organic product separate from the aqueous by-products. Furthermore, the microreactor oxidized a wide range of alcohols and remained active in excess of 100 trials without showing any loss of catalytic activity.

  13. Effect of nanostructure on osteoinduction of porous biphasic calcium phosphate ceramics.

    Science.gov (United States)

    Li, Bo; Liao, Xiaoling; Zheng, Li; Zhu, Xiangdong; Wang, Zhe; Fan, Hongsong; Zhang, Xingdong

    2012-10-01

    In order to evaluate the effect of the nanostructure of calcium phosphate ceramics on osteoinductive potential, porous biphasic calcium phosphate (BCP) ceramics with a nano- or submicron structure were prepared via microwave sintering and compared to conventional BCP ceramics. The selective protein adsorption of bovine serum albumin and lysozyme (LSZ) and the osteogenic differentiation of human mesenchymal stem cells in vitro was investigated. Porous BCP nanoceramics showed higher ability to adsorb proteins, especially low molecular weight protein of LSZ, than conventional BCP ceramics, and the BCP nanoceramics promoted bone sialoprotein expression more than conventional BCP did. Further in vivo study to investigate ectopic bone formation and bone repair efficiency proved the highly osteoinductive potential of nanostructured BCP ceramics. The results suggest that nanostructured BCP ceramics have the potential to become a new generation of bioceramics for bone tissue engineering grafts.

  14. Bullous variant of familial biphasic lichen amyloidosis: A unique combination of three rare presentations

    Directory of Open Access Journals (Sweden)

    Vijayalaxmi Veerabasappa Suranagi

    2015-01-01

    Full Text Available A 55-year-old man presented with multiple, itchy papules and macules on the trunk and extremities. Histopathologic examination of biopsy specimens taken from three different lesions showed a subepidermal blister with amyloid deposits in the dermal papillae. No systemic disease or involvement of other organs was detected. The clinical and histological findings were compatible with a bullous variant of lichen amyloidosis (LA. Primary cutaneous localized amyloidosis usually presents with papular, macular or nodular lesions. Bullous lesions associated with LA are very rare. Furthermore, patient had seven other members in the family with similar lesions, which is also a rare occurrence. We report a case with a rare combination of biphasic, bullous variant of familial LA.

  15. Pickering interfacial catalysis for biphasic systems: from emulsion design to green reactions.

    Science.gov (United States)

    Pera-Titus, Marc; Leclercq, Loïc; Clacens, Jean-Marc; De Campo, Floryan; Nardello-Rataj, Véronique

    2015-02-09

    Pickering emulsions are surfactant-free dispersions of two immiscible fluids that are kinetically stabilized by colloidal particles. For ecological reasons, these systems have undergone a resurgence of interest to mitigate the use of synthetic surfactants and solvents. Moreover, the use of colloidal particles as stabilizers provides emulsions with original properties compared to surfactant-stabilized emulsions, microemulsions, and micellar systems. Despite these specific advantages, the application of Pickering emulsions to catalysis has been rarely explored. This Minireview describes very recent examples of hybrid and composite amphiphilic materials for the design of interfacial catalysts in Pickering emulsions with special emphasis on their assets and challenges for industrially relevant biphasic reactions in fine chemistry, biofuel upgrading, and depollution.

  16. Kinetics of protein-protein complex coacervation and biphasic release of salbutamol sulfate from coacervate matrix.

    Science.gov (United States)

    Tiwari, Ananya; Bindal, Sonal; Bohidar, H B

    2009-01-12

    Turbidimetric titration was used to initiate associative intermolecular interactions between a pair of protein molecules, gelatin-A and gelatin-B, having complementary charges that led to pH-induced liquid-liquid phase separation and the formation of complex coacervate. The stoichiometric binding ratio was found to be [gelatin-A]/[gelatin-B]=3:2. The size of soluble intermolecular aggregates present in the supernatant exhibited interesting time-dependent coacervation because of residual electrostatic interactions. Dynamic light scattering and turbidity studies provided a systematic account of coacervation behavior. Rheology studies attributed the softening of the coacervate matrix to the presence of encapsulated salbutamol sulfate. The in vitro drug release kinetics was probed in simulated gastric fluid medium at physiological temperature (37 degrees C), which showed biphasic behavior. The initial release kinetics exhibited an exponential growth to saturation behavior, followed by a slower logarithmic release process.

  17. Biphasic responses of the honeybee heart to nanomolar concentrations of amitraz.

    Science.gov (United States)

    Papaefthimiou, Chrisovalantis; Papachristoforou, Alexandros; Theophilidis, George

    2013-09-01

    Amitraz is a pesticide targeting the octopaminergic receptors. In a previous study, octopamine, a biogenic amine, was found to induce a biphasic effect on the honeybee heart, inhibition at low concentrations and excitation at high concentrations. Furthermore, the honeybee heart was found to be far more sensitive to octopamine compared to other insect hearts. The objective of the present study was to investigate the effects of amitraz on the electrical and mechanical properties of the honeybee heart ex vivo and on the heart rate in vivo. In ex vivo conditions, amitraz at 10(-12) M caused a significant inhibition in the mechanical (pamitraz per bee induced a persistent increase of 134.28±4.07% (pamitraz, which is nevertheless still used inside beehives, ostensibly to "protect" the honeybees against their main parasite, Varroa destructor. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Association, partition, and surface activity in biphasic systems displaying relaxation oscillations.

    Science.gov (United States)

    Pradines, Vincent; Tadmouri, Rawad; Lavabre, Dominique; Micheau, Jean-Claude; Pimienta, Véronique

    2007-11-06

    Several biphasic systems giving rise to periodical Marangoni instability have been analyzed from the point of view of the physicochemical properties of the involved compounds. In each case, the compound at the origin of the oscillatory behavior has been identified: the reactant cetyltrimethylammonium bromide (CTAB) for the CTAB/picric acid (PH) system and the product of reaction dodecyl sulfate tetraalkylammonium (TAADS) for the sodium dodecyl sulfate/tetraalkylammonium bromide (SDS/TAAB) system. The properties of the latter system have been varied progressively by increasing the chain length of the tetraalkylammonium ion. Oscillations were observed whichever the direction of transfer (from water to dichloromethane and from dichloromethane to water). The comparison of the dynamic interfacial tension, recorded during transfer, to equilibrium measurements shows that the instability is favored when partition is highly in favor of the organic phase. The main criteria for the appearance of the instability are a high surface activity and a low interfacial adsorption.

  19. Facile synthesis and photocatalytic activity of bi-phase dispersible Cu-ZnO hybrid nanoparticles.

    Science.gov (United States)

    Liu, Xiao; Liu, HongLing; Zhang, WenXing; Li, XueMei; Fang, Ning; Wang, XianHong; Wu, JunHua

    2015-01-01

    Bi-phase dispersible Cu-ZnO hybrid nanoparticles were synthesized by one-pot non-aqueous nanoemulsion with the use of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO) as the surfactant. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) show high crystallinity of the Cu-ZnO hybrid nanoparticles and an average particle size of ~19.4 nm. The ultraviolet-visible light absorbance spectrometry (UV-vis) and photoluminescence spectrophotometry (PL) demonstrate well dispersibility and excellent optical performance of Cu-ZnO hybrid nanoparticles both in organic and aqueous solvent. The X-ray photoelectron spectroscopy (XPS) confirms Cu(1+) and Cu(2+) in ZnO. The observation using Sudan red (III) as probe molecule reveals that the Cu-ZnO hybrid nanoparticles possess enhanced photocatalytic activity and stability which are promising for potential applications in photocatalysis.

  20. Injectable Hydrogel Composite Based Gelatin-PEG and Biphasic Calcium Phosphate Nanoparticles for Bone Regeneration

    Science.gov (United States)

    Van, Thuy Duong; Tran, Ngoc Quyen; Nguyen, Dai Hai; Nguyen, Cuu Khoa; Tran, Dai Lam; Nguyen, Phuong Thi

    2016-05-01

    Gelatin hydrogels have recently attracted much attention for tissue regeneration because of their biocompatibility. In this study, we introduce poly-ethylene glycol (PEG)—grafted gelatin containing tyramine moieties which have been utilized for in situ enzyme-mediated hydrogel preparation. The hydrogel can be used to load nanoparticles of biphasic calcium phosphate, a mixture of hydroxyapatite and β-tricalcium phosphate, and forming injectable bio-composites. Proton nuclear magnetic resonance (1H NMR) spectra indicated that tyramine-functionalized polyethylene glycol-nitrophenyl carbonate ester was conjugated to the gelatin. The hydrogel composite was rapidly formed in situ (within a few seconds) in the presence of horseradish peroxidase and hydrogen peroxide. In vitro experiments with bio-mineralization on the hydrogel composite surfaces was well-observed after 2 weeks soaking in simulated body fluid solution. The obtained results indicated that the hydrogel composite could be a potential injectable material for bone regeneration.

  1. Obtaining of ceramics biphasic dense and porous; Obtencao de ceramicas bifasicas densas e porosas

    Energy Technology Data Exchange (ETDEWEB)

    Pallone, E.M.J.A.; Rigo, E.C.S., E-mail: eliria@usp.b [Universidade de Sao Paulo (FZEA/USP), Pirassununga, SP (Brazil). Dept. de Ciencias Basicas; Silva, K.L. [Universidade Estadual de Campinas (FEM/UNICAMP), SP (Brazil). Faculdade de Engenharia Mecanica; Rezende, M.E. [Universidade Sao Francisco, Itatiba, SP (Brazil); Fraga, A.F. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Marques, R.F.C. [Universidade Federal de Alfenas (UNIFAL), Pocos de Caldas, MG (Brazil)

    2010-07-01

    Among the bioceramic hydroxyapatite (HAP) and beta-tricalcium phosphate (beta-TCP) are materials commonly used in biomedical field. Their combined properties result in a material with absorbable and at the same time with bioactive surface. Called biphasic ceramics such materials respond more quickly when exposed to physiological environment. In this work, powders of HAP/beta-TCP were obtained by chemical precipitation. After obtaining the post-phase was added at a ratio of 0, 15% and 30w% aqueous solutions of corn starch in order to obtain porous bodies. After mixing the resulting solutions were dried, resigned in tablet form and sintered at 1300 deg C. The initial powder was characterized by X-ray diffraction with Rietveld refinement to quantify the phases present. Bodies-of-evidence has been characterized by calculating the bulk density, X-ray diffraction (XRD), scanning electron microscopy and diametral compression. (author)

  2. Perfluorinated quaternary ammonium salts of polyoxometalate anions: Fluorous biphasic oxidation catalysis with and without fluorous solvents

    Energy Technology Data Exchange (ETDEWEB)

    Maayan, Galia; Fish, Richard H.; Neumann, Ronny

    2003-05-28

    Perfluorinated quaternary ammonium cations, [CF{sub 3}(CF{sub 2}){sub 7}(CH{sub 2}){sub 3}]{sub 3}CH{sub 3}N{sup +} (RFN{sup +}), were synthesized and used as counter cations for the [WZnM{sub 2}(H{sub 2}O){sub 2}(ZnW{sub 9}O{sub 34}){sub 2}]{sup 12-} (M = Mn(II), Zn(II)), polyoxometalate. The (RFN{sup +}){sub 12}[WZnM{sub 2}(H{sub 2}O){sub 2}(ZnW9O{sub 34}){sub 2}] compounds were fluorous biphasic catalysts for alcohol and alkenol oxidation, and alkene epoxidation with aqueous hydrogen peroxide. Reaction protocols with or without a fluorous solvent were tested. The catalytic activity and selectivity was affected both by the hydrophobicity of the solvent and the substrate.

  3. Alendronate-Eluting Biphasic Calcium Phosphate (BCP Scaffolds Stimulate Osteogenic Differentiation

    Directory of Open Access Journals (Sweden)

    Sung Eun Kim

    2015-01-01

    Full Text Available Biphasic calcium phosphate (BCP scaffolds have been widely used in orthopedic and dental fields as osteoconductive bone substitutes. However, BCP scaffolds are not satisfactory for the stimulation of osteogenic differentiation and maturation. To enhance osteogenic differentiation, we prepared alendronate- (ALN- eluting BCP scaffolds. The coating of ALN on BCP scaffolds was confirmed by scanning electron microscopy (FE-SEM, energy-dispersive X-ray spectroscopy (EDS, and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR. An in vitro release study showed that release of ALN from ALN-eluting BCP scaffolds was sustained for up to 28 days. In vitro results revealed that MG-63 cells grown on ALN-eluting BCP scaffolds exhibited increased ALP activity and calcium deposition and upregulated gene expression of Runx2, ALP, OCN, and OPN compared with the BCP scaffold alone. Therefore, this study suggests that ALN-eluting BCP scaffolds have the potential to effectively stimulate osteogenic differentiation.

  4. Lactated Ringer-based storage solutions are equally well suited for the storage of fresh osteochondral allografts as cell culture medium-based storage solutions.

    Science.gov (United States)

    Harb, Afif; von Horn, Alexander; Gocalek, Kornelia; Schäck, Luisa Marilena; Clausen, Jan; Krettek, Christian; Noack, Sandra; Neunaber, Claudia

    2017-07-01

    Due to the rising interest in Europe to treat large cartilage defects with osteochondrale allografts, research aims to find a suitable solution for long-term storage of osteochondral allografts. This is further encouraged by the fact that legal restrictions currently limit the use of the ingredients from animal or human sources that are being used in other regions of the world (e.g. in the USA). Therefore, the aim of this study was A) to analyze if a Lactated Ringer (LR) based solution is as efficient as a Dulbecco modified Eagle's minimal essential medium (DMEM) in maintaining chondrocyte viability and B) at which storage temperature (4°C vs. 37°C) chondrocyte survival of the osteochondral allograft is optimally sustained. 300 cartilage grafts were collected from knees of ten one year-old Black Head German Sheep. The grafts were stored in four different storage solutions (one of them DMEM-based, the other three based on Lactated Ringer Solution), at two different temperatures (4 and 37°C) for 14 and 56days. At both points in time, chondrocyte survival as well as death rate, Glycosaminoglycan (GAG) content, and Hydroxyproline (HP) concentration were measured and compared between the grafts stored in the different solutions and at the different temperatures. Independent of the storage solutions tested, chondrocyte survival rates were higher when stored at 4°C compared to storage at 37°C both after short-term (14days) and long-term storage (56days). At no point in time did the DMEM-based solution show a superior chondrocyte survival compared to lactated Ringer based solution. GAG and HP content were comparable across all time points, temperatures and solutions. LR based solutions that contain only substances that are approved in Germany may be just as efficient for storing grafts as the USA DMEM-based solution gold standard. Moreover, in the present experiment storage of osteochondral allografts at 4°C was superior to storage at 37°C. Copyright © 2017

  5. Extracellular Calcium Modulates Chondrogenic and Osteogenic Differentiation of Human Adipose-Derived Stem Cells: A Novel Approach for Osteochondral Tissue Engineering Using a Single Stem Cell Source.

    Science.gov (United States)

    Mellor, Liliana F; Mohiti-Asli, Mahsa; Williams, John; Kannan, Arthi; Dent, Morgan R; Guilak, Farshid; Loboa, Elizabeth G

    2015-09-01

    We have previously shown that elevating extracellular calcium from a concentration of 1.8 to 8 mM accelerates and increases human adipose-derived stem cell (hASC) osteogenic differentiation and cell-mediated calcium accretion, even in the absence of any other soluble osteogenic factors in the culture medium. However, the effects of elevated calcium on hASC chondrogenic differentiation have not been reported. The goal of this study was to determine the effects of varied calcium concentrations on chondrogenic differentiation of hASC. We hypothesized that exposure to elevated extracellular calcium (8 mM concentration) in a chondrogenic differentiation medium (CDM) would inhibit chondrogenesis of hASC when compared to basal calcium (1.8 mM concentration) controls. We further hypothesized that a full osteochondral construct could be engineered by controlling local release of calcium to induce site-specific chondrogenesis and osteogenesis using only hASC as the cell source. Human ASC was cultured as micromass pellets in CDM containing transforming growth factor-β1 and bone morphogenetic protein 6 for 28 days at extracellular calcium concentrations of either 1.8 mM (basal) or 8 mM (elevated). Our findings indicated that elevated calcium induced osteogenesis and inhibited chondrogenesis in hASC. Based on these findings, stacked polylactic acid nanofibrous scaffolds containing either 0% or 20% tricalcium phosphate (TCP) nanoparticles were electrospun and tested for site-specific chondrogenesis and osteogenesis. Histological assays confirmed that human ASC differentiated locally to generate calcified tissue in layers containing 20% TCP, and cartilage in the layers with no TCP when cultured in CDM. This is the first study to report the effects of elevated calcium on chondrogenic differentiation of hASC, and to develop osteochondral nanofibrous scaffolds using a single cell source and controlled calcium release to induce site-specific differentiation. This approach

  6. Novel biphasic separations utilising highly selective molecularly imprinted polymers as biorecognition solvent extraction agents.

    Science.gov (United States)

    Castell, Oliver K; Allender, Christopher J; Barrow, David A

    2006-10-15

    Molecularly imprinted polymers (MIPs) represent a class of artificial receptors that promise an environmentally robust alternative to naturally occurring biorecognition elements of biosensing devices and systems. However, in general, the performance of conventional MIPs in aqueous environments is poor. In the study reported here, this limitation has been addressed by the novel application of MIPs as a solvent extraction solid phase in a biphasic solvent system. This paper describes a previously unreported use of MIPs as solvent extraction reagents, their successful application to aqueous sample media and the opportunities for utilisation of this unique system in novel biosensing and separation procedures. This study demonstrates the development of a novel biphasic solvent system utilising MIP in the extracting phase to enhance both efficiency and selectivity of a simple two phase liquid extraction. Monodisperse propranolol imprinted polymer microspheres [p(divinylbenzene-co-methacrylic acid)] were prepared by precipitation polymerisation. Initially, the affinity of the polymers for (R,S)-propranolol was assessed by established techniques whereby the MIP demonstrated greater affinity for the template than did the non-imprinted control polymer (NIP). Importantly, MIP performance was also assessed using the novel dual solvent system. The depletion of (R,S)-propranolol from the aqueous phase into the polymer containing organic phase was determined. When compared to control extractions containing no polymer the presence of MIP in the extracting solvent phase resulted in an increased extraction of (R,S)-propranolol from the aqueous phase. Importantly, this extraction was significantly greater in the presence of MIP when compared to NIP. This unique principle generates opportunities for MIP based extractions and chemical enrichments in industrial applications, offering commercial, ecological and practical advantages to traditional solvent extraction techniques. The

  7. Kinetics of Horseradish Peroxidase-Catalyzed Nitration of Phenol in a Biphasic System.

    Science.gov (United States)

    Kong, Mingming; Zhang, Yang; Li, Qida; Dong, Runan; Gao, Haijun

    2017-02-28

    The use of peroxidase in the nitration of phenols is gaining interest as compared with traditional chemical reactions. We investigated the kinetic characteristics of phenol nitration catalyzed by horseradish peroxidase (HRP) in an aqueous-organic biphasic system using n-butanol as the organic solvent and NO2(-) and H2O2 as substrates. The reaction rate was mainly controlled by the reaction kinetics in the aqueous phase when appropriate agitation was used to enhance mass transfer in the biphasic system. The initial velocity of the reaction increased with increasing HRP concentration. Additionally, an increase in the substrate concentrations of phenol (0-2 mM in organic phase) or H2O2 (0-0.1 mM in aqueous phase) enhanced the nitration efficiency catalyzed by HRP. In contrast, high concentrations of organic solvent decreased the kinetic parameter Vmax/Km. No inhibition of enzyme activity was observed when the concentrations of phenol and H2O2 were at or below 10 mM and 0.1 mM, respectively. On the basis of the peroxidase catalytic mechanism, a double-substrate ping-pong kinetic model was established. The kinetic parameters were Km(H2O2)= 1.09 mM, Km(PhOH) = 9.45 mM, and Vmax = 0.196 mM/min. The proposed model was well fit to the data obtained from additional independent experiments under the suggested optimal synthesis conditions. The kinetic model developed in this paper lays a foundation for further comprehensive study of enzymatic nitration kinetics.

  8. Assessing composition and structure of soft biphasic media from Kelvin-Voigt fractional derivative model parameters

    Science.gov (United States)

    Zhang, Hongmei; Wang, Yue; Fatemi, Mostafa; Insana, Michael F.

    2017-03-01

    Kelvin-Voigt fractional derivative (KVFD) model parameters have been used to describe viscoelastic properties of soft tissues. However, translating model parameters into a concise set of intrinsic mechanical properties related to tissue composition and structure remains challenging. This paper begins by exploring these relationships using a biphasic emulsion materials with known composition. Mechanical properties are measured by analyzing data from two indentation techniques—ramp-stress relaxation and load-unload hysteresis tests. Material composition is predictably correlated with viscoelastic model parameters. Model parameters estimated from the tests reveal that elastic modulus E 0 closely approximates the shear modulus for pure gelatin. Fractional-order parameter α and time constant τ vary monotonically with the volume fraction of the material’s fluid component. α characterizes medium fluidity and the rate of energy dissipation, and τ is a viscous time constant. Numerical simulations suggest that the viscous coefficient η is proportional to the energy lost during quasi-static force-displacement cycles, E A . The slope of E A versus η is determined by α and the applied indentation ramp time T r. Experimental measurements from phantom and ex vivo liver data show close agreement with theoretical predictions of the η -{{E}A} relation. The relative error is less than 20% for emulsions 22% for liver. We find that KVFD model parameters form a concise features space for biphasic medium characterization that described time-varying mechanical properties. The experimental work was carried out at the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Methodological development, including numerical simulation and all data analysis, were carried out at the school of Life Science and Technology, Xi’an JiaoTong University, 710049, China.

  9. Seizure characteristics of epilepsy in childhood after acute encephalopathy with biphasic seizures and late reduced diffusion.

    Science.gov (United States)

    Ito, Yuji; Natsume, Jun; Kidokoro, Hiroyuki; Ishihara, Naoko; Azuma, Yoshiteru; Tsuji, Takeshi; Okumura, Akihisa; Kubota, Tetsuo; Ando, Naoki; Saitoh, Shinji; Miura, Kiyokuni; Negoro, Tamiko; Watanabe, Kazuyoshi; Kojima, Seiji

    2015-08-01

    The aim of this study was to clarify characteristics of post-encephalopathic epilepsy (PEE) in children after acute encephalopathy with biphasic seizures and late reduced diffusion (AESD), paying particular attention to precise diagnosis of seizure types. Among 262 children with acute encephalopathy/encephalitis registered in a database of the Tokai Pediatric Neurology Society between 2005 and 2012, 44 were diagnosed with AESD according to the clinical course and magnetic resonance imaging (MRI) findings and were included in this study. Medical records were reviewed to investigate clinical data, MRI findings, neurologic outcomes, and presence or absence of PEE. Seizure types of PEE were determined by both clinical observation by pediatric neurologists and ictal video-electroencephalography (EEG) recordings. Of the 44 patients after AESD, 10 (23%) had PEE. The period between the onset of encephalopathy and PEE ranged from 2 to 39 months (median 8.5 months). Cognitive impairment was more severe in patients with PEE than in those without. Biphasic seizures and status epilepticus during the acute phase of encephalopathy did not influence the risk of PEE. The most common seizure type of PEE on clinical observation was focal seizures (n = 5), followed by epileptic spasms (n = 4), myoclonic seizures (n = 3), and tonic seizures (n = 2). In six patients with PEE, seizures were induced by sudden unexpected sounds. Seizure types confirmed by ictal video-EEG recordings were epileptic spasms and focal seizures with frontal onset, and all focal seizures were startle seizures induced by sudden acoustic stimulation. Intractable daily seizures remain in six patients with PEE. We demonstrate seizure characteristics of PEE in children after AESD. Epileptic spasms and startle focal seizures are common seizure types. The specific seizure types may be determined by the pattern of diffuse subcortical white matter injury in AESD and age-dependent reorganization of the brain

  10. Integrating folding kinetics and protein function: biphasic kinetics and dual binding specificity in a WW domain.

    Science.gov (United States)

    Karanicolas, John; Brooks, Charles L

    2004-03-09

    Because of the association of beta-sheet formation with the initiation and propagation of amyloid diseases, model systems have been sought to further our understanding of this process. WW domains have been proposed as one such model system. Whereas the folding of the WW domains from human Yes-associated protein (YAP) and Pin have been shown to obey single-exponential kinetics, the folding of the WW domain from formin-binding protein (FBP) 28 has been shown to proceed via biphasic kinetics. From an analysis of free-energy landscapes from atomic-level molecular dynamics simulations, the biphasic folding kinetics observed in the FBP WW domain may be traced to the ability of this WW domain to adopt two slightly different forms of packing in its hydrophobic core. This conformational change is propagated along the peptide backbone and affects the position of a tryptophan residue shown in other WW domains to play a key role in binding. The WW domains of Pin and YAP do not support more than one type of packing each, leading to monophasic folding kinetics. The ability of the FBP WW domain to assume two different types of packing may, in turn, explain the capacity of this WW domain to bind two classes of ligand, a property that is not shared by other WW domains. These findings lead to the hypothesis that lability with respect to conformations separated by an observable barrier as a requirement for function is incompatible with the ability of a protein to fold via single-exponential kinetics.

  11. Survival kinetics of starving bacteria is biphasic and density-dependent.

    Directory of Open Access Journals (Sweden)

    Andy Phaiboun

    2015-04-01

    Full Text Available In the lifecycle of microorganisms, prolonged starvation is prevalent and sustaining life during starvation periods is a vital task. In the literature, it is commonly assumed that survival kinetics of starving microbes follows exponential decay. This assumption, however, has not been rigorously tested. Currently, it is not clear under what circumstances this assumption is true. Also, it is not known when such survival kinetics deviates from exponential decay and if it deviates, what underlying mechanisms for the deviation are. Here, to address these issues, we quantitatively characterized dynamics of survival and death of starving E. coli cells. The results show that the assumption--starving cells die exponentially--is true only at high cell density. At low density, starving cells persevere for extended periods of time, before dying rapidly exponentially. Detailed analyses show intriguing quantitative characteristics of the density-dependent and biphasic survival kinetics, including that the period of the perseverance is inversely proportional to cell density. These characteristics further lead us to identification of key underlying processes relevant for the perseverance of starving cells. Then, using mathematical modeling, we show how these processes contribute to the density-dependent and biphasic survival kinetics observed. Importantly, our model reveals a thrifty strategy employed by bacteria, by which upon sensing impending depletion of a substrate, the limiting substrate is conserved and utilized later during starvation to delay cell death. These findings advance quantitative understanding of survival of microbes in oligotrophic environments and facilitate quantitative analysis and prediction of microbial dynamics in nature. Furthermore, they prompt revision of previous models used to analyze and predict population dynamics of microbes.

  12. Regulation of the demographic structure in isomorphic biphasic life cycles at the spatial fine scale.

    Directory of Open Access Journals (Sweden)

    Vasco Manuel Nobre de Carvalho da Silva Vieira

    Full Text Available Isomorphic biphasic algal life cycles often occur in the environment at ploidy abundance ratios (Haploid:Diploid different from 1. Its spatial variability occurs within populations related to intertidal height and hydrodynamic stress, possibly reflecting the niche partitioning driven by their diverging adaptation to the environment argued necessary for their prevalence (evolutionary stability. Demographic models based in matrix algebra were developed to investigate which vital rates may efficiently generate an H:D variability at a fine spatial resolution. It was also taken into account time variation and type of life strategy. Ploidy dissimilarities in fecundity rates set an H:D spatial structure miss-fitting the ploidy fitness ratio. The same happened with ploidy dissimilarities in ramet growth whenever reproductive output dominated the population demography. Only through ploidy dissimilarities in looping rates (stasis, breakage and clonal growth did the life cycle respond to a spatially heterogeneous environment efficiently creating a niche partition. Marginal locations were more sensitive than central locations. Related results have been obtained experimentally and numerically for widely different life cycles from the plant and animal kingdoms. Spore dispersal smoothed the effects of ploidy dissimilarities in fertility and enhanced the effects of ploidy dissimilarities looping rates. Ploidy dissimilarities in spore dispersal could also create the necessary niche partition, both over the space and time dimensions, even in spatial homogeneous environments and without the need for conditional differentiation of the ramets. Fine scale spatial variability may be the key for the prevalence of isomorphic biphasic life cycles, which has been neglected so far.

  13. Biphasic cultivation strategy to avoid Epo-Fc aggregation and optimize protein expression.

    Science.gov (United States)

    Kaisermayer, Christian; Reinhart, David; Gili, Andreas; Chang, Martina; Aberg, Per-Mikael; Castan, Andreas; Kunert, Renate

    2016-06-10

    In biphasic cultivations, the culture conditions are initially kept at an optimum for rapid cell growth and biomass accumulation. In the second phase, the culture is shifted to conditions ensuring maximum specific protein production and the protein quality required. The influence of specific culture parameters is cell line dependent and their impact on product quality needs to be investigated. In this study, a biphasic cultivation strategy for a Chinese hamster ovary (CHO) cell line expressing an erythropoietin fusion protein (Epo-Fc) was developed. Cultures were run in batch mode and after an initial growth phase, cultivation temperature and pH were shifted. Applying a DoE (Design of Experiments) approach, a fractional factorial design was used to systematically evaluate the influence of cultivation temperature and pH as well as their synergistic effect on cell growth as well as on recombinant protein production and aggregation. All three responses were influenced by the cultivation temperature. Additionally, an interaction between pH and temperature was found to be related to protein aggregation. Compared with the initial standard conditions of 37°C and pH 7.05, a parameter shift to low temperature and acidic pH resulted in a decrease in the aggregate fraction from 75% to less than 1%. Furthermore, the synergistic effect of temperature and pH substantially lowered the cell-specific rates of glucose and glutamine consumption as well as lactate and ammonium production. The optimized culture conditions also led to an increase of the cell-specific rates of recombinant Epo-Fc production, thus resulting in a more economic bioprocess.

  14. Subchondral chitosan/blood implant-guided bone plate resorption and woven bone repair is coupled to hyaline cartilage regeneration from microdrill holes in aged rabbit knees.

    Science.gov (United States)

    Guzmán-Morales, J; Lafantaisie-Favreau, C-H; Chen, G; Hoemann, C D

    2014-02-01

    Little is known of how to routinely elicit hyaline cartilage repair tissue in middle-aged patients. We tested the hypothesis that in skeletally aged rabbit knees, microdrill holes can be stimulated to remodel the bone plate and induce a more integrated, voluminous and hyaline cartilage repair tissue when treated by subchondral chitosan/blood implants. New Zealand White rabbits (13 or 32 months old, N = 7) received two 1.5 mm diameter, 2 mm depth drill holes in each knee, either left to bleed as surgical controls or press-fit with a 10 kDa (distal hole: 10K) or 40 kDa (proximal hole: 40K) chitosan/blood implant with fluorescent chitosan tracer. Post-operative knee effusion was documented. Repair tissues at day 0 (N = 1) and day 70 post-surgery (N = 6) were analyzed by micro-computed tomography, and by histological scoring and histomorphometry (SafO, Col-2, and Col-1) at day 70. All chitosan implants were completely cleared after 70 days, without increasing transient post-operative knee effusion compared to controls. Proximal control holes had worse osteochondral repair than distal holes. Both implant formulations induced bone remodeling and improved lateral integration of the bone plate at the hole edge. The 40K implant inhibited further bone repair inside 50% of the proximal holes, while the 10K implant specifically induced a "wound bloom" reaction, characterized by decreased bone plate density in a limited zone beyond the initial hole edge, and increased woven bone (WB) plate repair inside the initial hole (P = 0.016), which was accompanied by a more voluminous and hyaline cartilage repair (P hyaline cartilage repair can be promoted by treating acute drill holes with a biodegradable subchondral implant that elicits bone plate resorption followed by anabolic WB repair within a 70-day repair period. Copyright © 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  15. Dental Implant Systems

    Science.gov (United States)

    Oshida, Yoshiki; Tuna, Elif B.; Aktören, Oya; Gençay, Koray

    2010-01-01

    Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s) in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities. PMID:20480036

  16. Dental Implant Systems

    Directory of Open Access Journals (Sweden)

    Yoshiki Oshida

    2010-04-01

    Full Text Available Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities.

  17. Nanotechnology for dental implants.

    Science.gov (United States)

    Tomsia, Antoni P; Lee, Janice S; Wegst, Ulrike G K; Saiz, Eduardo

    2013-01-01

    With the advent of nanotechnology, an opportunity exists for the engineering of new dental implant materials. Metallic dental implants have been successfully used for decades, but they have shortcomings related to osseointegration and mechanical properties that do not match those of bone. Absent the development of an entirely new class of materials, faster osseointegration of currently available dental implants can be accomplished by various surface modifications. To date, there is no consensus regarding the preferred method(s) of implant surface modification, and further development will be required before the ideal implant surface can be created, let alone become available for clinical use. Current approaches can generally be categorized into three areas: ceramic coatings, surface functionalization, and patterning on the micro- to nanoscale. The distinctions among these are imprecise, as some or all of these approaches can be combined to improve in vivo implant performance. These surface improvements have resulted in durable implants with a high percentage of success and long-term function. Nanotechnology has provided another set of opportunities for the manipulation of implant surfaces in its capacity to mimic the surface topography formed by extracellular matrix components of natural tissue. The possibilities introduced by nanotechnology now permit the tailoring of implant chemistry and structure with an unprecedented degree of control. For the first time, tools are available that can be used to manipulate the physicochemical environment and monitor key cellular events at the molecular level. These new tools and capabilities will result in faster bone formation, reduced healing time, and rapid recovery to function.

  18. Bioceramics for implant coatings

    Directory of Open Access Journals (Sweden)

    Allison A Campbell

    2003-11-01

    Early research in this field focused on understanding the biomechanical properties of metal implants, but recent work has turned toward improving the biological properties of these devices. This has led to the introduction of calcium phosphate (CaP bioceramics as a bioactive interface between the bulk metal impart and the surrounding tissue. The first CaP coatings were produced via vapor phase processes, but more recently solution-based and biomimetic methods have emerged. While each approach has its own intrinsic materials and biological properties, in general CaP coatings promise to improve implant biocompatibility and ultimately implant longevity.

  19. Delayed breast implant reconstruction

    DEFF Research Database (Denmark)

    Hvilsom, Gitte B.; Hölmich, Lisbet R.; Steding-Jessen, Marianne

    2011-01-01

    the period 1999 to 2006; 239 one-stage procedures and 353 two-stage procedures. The postoperative course through November 2009 was evaluated by cumulative incidence adjusting for competing risks for the selected outcomes; hematoma, infection, seroma, implant rupture, severe capsular contracture (modified.......7% for severe capsular contracture, 32.3% for displacement/asymmetry of the implant and 38.6% for reoperation. When comparing one- and two-stage procedures, we observed significantly higher risk estimates for infection, seroma and extrusion of the implant following two-stage procedures, whereas the risk...

  20. Biomedical implantable microelectronics.

    Science.gov (United States)

    Meindl, J D

    1980-10-17

    Innovative applications of microelectronics in new biomedical implantable instruments offer a singular opportunity for advances in medical research and practice because of two salient factors: (i) beyond all other types of biomedical instruments, implants exploit fully the inherent technical advantages--complex functional capability, high reliability, lower power drain, small size and weight-of microelectronics, and (ii) implants bring microelectronics into intimate association with biological systems. The combination of these two factors enables otherwise impossible new experiments to be conducted and new paostheses developed that will improve the quality of human life.

  1. Optimization of dental implantation

    Science.gov (United States)

    Dol, Aleksandr V.; Ivanov, Dmitriy V.

    2017-02-01

    Modern dentistry can not exist without dental implantation. This work is devoted to study of the "bone-implant" system and to optimization of dental prostheses installation. Modern non-invasive methods such as MRI an 3D-scanning as well as numerical calculations and 3D-prototyping allow to optimize all of stages of dental prosthetics. An integrated approach to the planning of implant surgery can significantly reduce the risk of complications in the first few days after treatment, and throughout the period of operation of the prosthesis.

  2. Repair of Cranial Bone Defects Using rhBMP2 and Submicron Particle of Biphasic Calcium Phosphate Ceramics with Through-Hole

    Directory of Open Access Journals (Sweden)

    Byung-Chul Jeong

    2015-01-01

    Full Text Available Recently a submicron particle of biphasic calcium phosphate ceramic (BCP with through-hole (donut-shaped BCP (d-BCP was developed for improving the osteoconductivity. This study was performed to examine the usefulness of d-BCP for the delivery of osteoinductive rhBMP2 and the effectiveness on cranial bone regeneration. The d-BCP was soaked in rhBMP2 solution and then freeze-dried. Scanning electron microscope (SEM, energy dispersive spectroscopy (EDS, and Raman spectroscopy analyses confirmed that rhBMP2 was well delivered onto the d-BCP surface and the through-hole. The bioactivity of the rhBMP2/d-BCP composite was validated in MC3T3-E1 cells as an in vitro model and in critical-sized cranial defects in C57BL/6 mice. When freeze-dried d-BCPs with rhBMP2 were placed in transwell inserts and suspended above MC3T3-E1, alkaline phosphatase activity and osteoblast-specific gene expression were increased compared to non-rhBMP2-containing d-BCPs. For evaluating in vivo effectiveness, freeze-dried d-BCPs with or without rhBMP2 were implanted into critical-sized cranial defects. Microcomputed tomography and histologic analysis showed that rhBMP2-containing d-BCPs significantly enhanced cranial bone regeneration compared to non-rhBMP2-containing control. These results suggest that a combination of d-BCP and rhBMP2 can accelerate bone regeneration, and this could be used to develop therapeutic strategies in hard tissue healing.

  3. Lumbar interbody fusion with porous biphasic calcium phosphate enhanced by recombinant bone morphogenetic protein-2/silk fibroin sustained-released microsphere: an experimental study on sheep model.

    Science.gov (United States)

    Chen, Liang; Liu, Hai-Long; Gu, Yong; Feng, Yu; Yang, Hui-Lin

    2015-03-01

    Biphasic calcium phosphate (BCP) has been investigated extensively as a bone substitute nowadays. However, the bone formation capacity of BCP is limited owing to lack of osteoinduction. Silk fibroin (SF) has a structure similar to type I collagen, and could be developed to a microsphere for the sustained-release of rhBMP-2. In our previous report, bioactivity of BCP could be enhanced by rhBMP-2/SF microsphere (containing 0.5 µg rhBMP-2) in vitro. However, the bone regeneration performance of the composite in vivo was not investigated. Thus, the purpose of this study was to evaluate the efficacy of BCP/rhBMP-2/SF in a sheep lumbar fusion model. A BCP and rhBMP-2/SF microsphere was developed, and then was integrated into a BCP/rhBMP-2/SF composite. BCP, BCP/rhBMP-2 and BCP/rhBMP-2/SF were implanted randomly into the disc spaces of 30 sheep at the levels of L1/2, L3/4 and L5/6. After sacrificed, the fusion segments were evaluated by manual palpation, CT scan, biomechanical testing and histology at 3 and 6 months, respectively. The composite demonstrated a burst-release of rhBMP-2 (39.1 ± 2.8 %) on the initial 4 days and a sustained-release (accumulative 81.3 ± 4.9 %) for more than 28 days. The fusion rates, semi-quantitative CT scores, fusion stiffness in bending in all directions and histologic scores of BCP/rhBMP-2/SF were significantly greater than BCP and BCP/rhBMP-2 at each time point, respectively (P sheep using BCP constructs.

  4. Repair of Cranial Bone Defects Using rhBMP2 and Submicron Particle of Biphasic Calcium Phosphate Ceramics with Through-Hole.

    Science.gov (United States)

    Jeong, Byung-Chul; Choi, Hyuck; Hur, Sung-Woong; Kim, Jung-Woo; Oh, Sin-Hye; Kim, Hyun-Seung; Song, Soo-Chang; Lee, Keun-Bae; Park, Kwang-Bum; Koh, Jeong-Tae

    2015-01-01

    Recently a submicron particle of biphasic calcium phosphate ceramic (BCP) with through-hole (donut-shaped BCP (d-BCP)) was developed for improving the osteoconductivity. This study was performed to examine the usefulness of d-BCP for the delivery of osteoinductive rhBMP2 and the effectiveness on cranial bone regeneration. The d-BCP was soaked in rhBMP2 solution and then freeze-dried. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and Raman spectroscopy analyses confirmed that rhBMP2 was well delivered onto the d-BCP surface and the through-hole. The bioactivity of the rhBMP2/d-BCP composite was validated in MC3T3-E1 cells as an in vitro model and in critical-sized cranial defects in C57BL/6 mice. When freeze-dried d-BCPs with rhBMP2 were placed in transwell inserts and suspended above MC3T3-E1, alkaline phosphatase activity and osteoblast-specific gene expression were increased compared to non-rhBMP2-containing d-BCPs. For evaluating in vivo effectiveness, freeze-dried d-BCPs with or without rhBMP2 were implanted into critical-sized cranial defects. Microcomputed tomography and histologic analysis showed that rhBMP2-containing d-BCPs significantly enhanced cranial bone regeneration compared to non-rhBMP2-containing control. These results suggest that a combination of d-BCP and rhBMP2 can accelerate bone regeneration, and this could be used to develop therapeutic strategies in hard tissue healing.

  5. 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.

  6. Treatment of osteochondral lesions of the talus with autologous collagen-induced chondrogenesis: clinical and magnetic resonance evaluation at one-year follow-up

    Science.gov (United States)

    USUELLI, FEDERICO GIUSEPPE; GRASSI, MIRIAM; MANZI, LUIGI; GUARRELLA, VINCENZO; BOGA, MICHELE; DE GIROLAMO, LAURA

    2016-01-01

    Purpose the aim of this study is to report the clinical and imaging results recorded by a series of patients in whom osteochondral lesions of the talus (OLTs) were repaired using the autologous collagen-induced chondrogenesis (ACIC) technique with a completely arthroscopic approach. Methods nine patients (mean age 37.4±10 years) affected by OLTs (lesion size 2.1±0.9 cm2) were treated with the ACIC technique. The patients were evaluated clinically both preoperatively and at 12 months after surgery using the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale (AOFAS) and a visual analog scale (VAS). For morphological evaluation, the magnetic resonance observation of cartilage repair tissue (MOCART) score was used. Results the AOFAS score improved from 51.4±11.6 preoperatively to 71.8±20.6 postoperatively, while the VAS value decreased from 6.9±1.8 to 3.2±1.9. The mean MOCART score was 51.7±16.6 at 12 months of follow-up; these scores did not directly correlate with the clinical results. Conclusion use of the ACIC technique for arthroscopic repair of OLTs allowed satisfactory clinical results to be obtained in most of the patients as soon as one year after surgery, with no major complications or delayed revision surgery. ACIC is a valid and low-invasive surgical technique for the treatment of chondral and osteochondral defects of the talus. Level of evidence therapeutic case series, level IV. PMID:27602347

  7. Osteochondral Biopsy Analysis Demonstrates That BST-CarGel Treatment Improves Structural and Cellular Characteristics of Cartilage Repair Tissue Compared With Microfracture

    Science.gov (United States)

    Méthot, Stéphane; Changoor, Adele; Tran-Khanh, Nicolas; Hoemann, Caroline D.; Stanish, William D.; Restrepo, Alberto; Shive, Matthew S.; Buschmann, Michael D.

    2016-01-01

    Objective The efficacy and safety of BST-CarGel, a chitosan-based medical device for cartilage repair, was compared with microfracture alone at 1 year during a multicenter randomized controlled trial (RCT) in the knee. The quality of repair tissue of osteochondral biopsies collected from a subset of patients was compared using blinded histological assessments. Methods The international RCT evaluated repair tissue quantity and quality by 3-dimensional quantitative magnetic resonance imaging as co-primary endpoints at 12 months. At an average of 13 months posttreatment, 21/41 BST-CarGel and 17/39 microfracture patients underwent elective second look arthroscopies as a tertiary endpoint, during which ICRS (International Cartilage Repair Society) macroscopic scoring was carried out, and osteochondral biopsies were collected. Stained histological sections were evaluated by blinded readers using ICRS I and II histological scoring systems. Collagen organization was evaluated using a polarized light microscopy score. Results BST-CarGel treatment resulted in significantly better ICRS macroscopic scores (P = 0.0002) compared with microfracture alone, indicating better filling, integration, and tissue appearance. Histologically, BST-CarGel resulted in a significant improvement of structural parameters—Surface Architecture (P = 0.007) and Surface/Superficial Assessment (P = 0.042)—as well as cellular parameters—Cell Viability (P = 0.006) and Cell Distribution (P = 0.032). No histological parameters were significantly better for the microfracture group. BST-CarGel treatment also resulted in a more organized repair tissue with collagen stratification more similar to native hyaline cartilage, as measured by polarized light microscopy scoring (P = 0.0003). Conclusion Multiple and independent analyses in this biopsy substudy demonstrated that BST-CarGel treatment results in improved structural and cellular characteristics of repair tissue at 1 year posttreatment compared with

  8. "One-step" bone marrow-derived cells transplantation and joint debridement for osteochondral lesions of the talus in ankle osteoarthritis: clinical and radiological outcomes at 36 months.

    Science.gov (United States)

    Buda, Roberto; Castagnini, Francesco; Cavallo, Marco; Ramponi, Laura; Vannini, Francesca; Giannini, Sandro

    2016-01-01

    Ankle osteoarthritis (OA) is a challenging pathology, often requiring surgical treatments. In young patients, joint sparing, biologic procedures would be desirable. Recently, a few reports have described the efficacy of bone marrow stem cells in OA. Considering the good outcomes of one-step bone marrow derived cells transplantation (BMDCT) for osteochondral lesions of the talus (OLT), we applied this procedure for OLT in concomitant ankle OA. 56 patients, with a mean age of 35.6 years (range 16–50), who suffered from OLT and ankle OA, were treated using BMDCT. All patients were clinically checked using AOFAS score, in the pre-operative setting until the final follow-up of 36 months. Weight-bearing radiographs and MRI evaluation using Mocart score were performed, preoperatively and postoperatively. The whole clinical outcome had a remarkable improvement at 12 months, a further amelioration at 24 months and a lowering trend at 36 months (77.8 ± 18.3). Early OA had better outcomes. 16 patients required another treatment and they were considered failures. Clinical outcome significantly correlates with OA degree, BMI, associate procedures. Radiographs were in line with clinical results. MRI evaluation showed signs of osteochondral repair. BMDCT showed encouraging clinical and radiological outcomes at short-term follow-up. This procedure should be applied in young and selected patients, excluding severe ankle degeneration, where the results are critical. Longer follow-ups and larger case series are needed to confirm these results and if this treatment could be effective in postponing end-stage procedures. IV.

  9. 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.

  10. DEALING WITH DENTAL IMPLANT FAILURES

    Science.gov (United States)

    Levin, Liran

    2008-01-01

    An implant-supported restoration offers a predictable treatment for tooth replacement. Reported success rates for dental implants are high. Nevertheless, failures that mandate immediate implant removal do occur. The consequences of implant removal jeopardize the clinician's efforts to accomplish satisfactory function and esthetics. For the patient, this usually involves further cost and additional procedures. The aim of this paper is to describe different methods and treatment modalities to deal with dental implant failure. The main topics for discussion include identifying the failing implant, implants replacing failed implants at the exact site, and the use of other restorative options. When an implant fails, a tailor made treatment plan should be provided to each patient according to all relevant variables. Patients should be informed regarding all possible treatment modalities following implant failure and give their consent to the most appropriate treatment option for them. PMID:19089213

  11. Dealing with dental implant failures

    Directory of Open Access Journals (Sweden)

    Liran Levin

    2008-06-01

    Full Text Available An implant-supported restoration offers a predictable treatment for tooth replacement. Reported success rates for dental implants are high. Nevertheless, failures that mandate immediate implant removal do occur. The consequences of implant removal jeopardize the clinician's efforts to accomplish satisfactory function and esthetics. For the patient, this usually involves further cost and additional procedures. The aim of this paper is to describe different methods and treatment modalities to deal with dental implant failure. The main topics for discussion include identifying the failing implant, implants replacing failed implants at the exact site, and the use of other restorative options.When an implant fails, a tailor made treatment plan should be provided to each patient according to all relevant variables. Patients should be informed regarding all possible treatment modalities following implant failure and give their consent to the most appropriate treatment option for them.

  12. Improved cartilage regeneration by implantation of acellular biomaterials after bone marrow stimulation: a systematic review and meta-analysis of animal studies

    Directory of Open Access Journals (Sweden)

    Michiel W. Pot

    2016-09-01

    Full Text Available Microfracture surgery may be applied to treat cartilage defects. During the procedure the subchondral bone is penetrated, allowing bone marrow-derived mesenchymal stem cells to migrate towards the defect site and form new cartilage tissue. Microfracture surgery generally results in the formation of mechanically inferior fibrocartilage. As a result, this technique offers only temporary clinical improvement. Tissue engineering and regenerative medicine may improve the outcome of microfracture surgery. Filling the subchondral defect with a biomaterial may provide a template for the formation of new hyaline cartilage tissue. In this study, a systematic review and meta-analysis were performed to assess the current evidence for the efficacy of cartilage regeneration in preclinical models using acellular biomaterials implanted after marrow stimulating techniques (microfracturing and subchondral drilling compared to the natural healing response of defects. The review aims to provide new insights into the most effective biomaterials, to provide an overview of currently existing knowledge, and to identify potential lacunae in current studies to direct future research. A comprehensive search was systematically performed in PubMed and EMBASE (via OvidSP using search terms related to tissue engineering, cartilage and animals. Primary studies in which acellular biomaterials were implanted in osteochondral defects in the knee or ankle joint in healthy animals were included and study characteristics tabulated (283 studies out of 6,688 studies found. For studies comparing non-treated empty defects to defects containing implanted biomaterials and using semi-quantitative histology as outcome measure, the risk of bias (135 studies was assessed and outcome data were collected for meta-analysis (151 studies. Random-effects meta-analyses were performed, using cartilage regeneration as outcome measure on an absolute 0–100% scale. Implantation of acellular

  13. Superelastic Orthopedic Implant Coatings

    Science.gov (United States)

    Fournier, Eric; Devaney, Robert; Palmer, Matthew; Kramer, Joshua; El Khaja, Ragheb; Fonte, Matthew

    2014-07-01

    The demand for hip and knee replacement surgery is substantial and growing. Unfortunately, most joint replacement surgeries will fail within 10-25 years, thereby requiring an arduous, painful, and expensive revision surgery. To address this issue, a novel orthopedic implant coating material ("eXalt") has been developed. eXalt is comprised of super elastic nitinol wire that is knit into a three-dimensional spacer fabric structure. eXalt expands in vivo to conform to the implantation site and is porous to allow for bone ingrowth. The safety and efficacy of eXalt were evaluated through structural analysis, mechanical testing, and a rabbit implantation model. The results demonstrate that eXalt meets or exceeds the performance of current coating technologies with reduced micromotion, improved osseointegration, and stronger implant fixation in vivo.

  14. MEMS biomedical implants

    Institute of Scientific and Technical Information of China (English)

    Tai Yuchong

    2012-01-01

    The field of micro-electro-mechanical systems (MEMS) has advanced tremendously for the last 20 years. Most commercially noticeably, the field has successfully advanced from pressure sensors to micro physical sensors, such as accelerometers and gyros, for handheld electronics application. In parallel, MEMS has also advanced into micro total analysis system(TAS) and/or lab-on-a-chip applications. This article would discuss a relatively new but promising future direction towards MEMS biomedical implants. Specifically, Parylene C has been explored to be used as a good MEMS implant material and will be discussed in detail. Demonstrated implant devices, such as retinal and spinal cord implants, are presented in this article.

  15. Risks of Breast Implants

    Science.gov (United States)

    ... an infection or injury. Demonstrated by redness, swelling, warmth, pain and or/loss of function. Lymphedema or ... Overfilling or underfilling of saline-filled breast implants Physical stresses such as trauma or intense physical pressure ...

  16. Positive effects of cell-free porous PLGA implants and early loading exercise on hyaline cartilage regeneration in rabbits.

    Science.gov (United States)

    Chang, Nai-Jen; Lin, Chih-Chan; Shie, Ming-You; Yeh, Ming-Long; Li, Chien-Feng; Liang, Peir-In; Lee, Kuan-Wei; Shen, Pei-Hsun; Chu, Chih-Jou

    2015-12-01

    The regeneration of hyaline cartilage remains clinically challenging. Here, we evaluated the therapeutic effects of using cell-free porous poly(lactic-co-glycolic acid) (PLGA) graft implants (PGIs) along with early loading exercise to repair a full-thickness osteochondral defect. Rabbits were randomly allocated to a treadmill exercise (TRE) group or a sedentary (SED) group and were prepared as either a PGI model or an empty defect (ED) model. TRE was performed as a short-term loading exercise; SED was physical inactivity in a free cage. The knees were evaluated at 6 and 12 weeks after surgery. At the end of testing, none of the knees developed synovitis, formed osteophytes, or became infected. Macroscopically, the PGI-TRE group regenerated a smooth articular surface, with transparent new hyaline-like tissue soundly integrated with the neighboring cartilage, but the other groups remained distinct at the margins with fibrous or opaque tissues. In a micro-CT analysis, the synthesized bone volume/tissue volume (BV/TV) was significantly higher in the PGI-TRE group, which also had integrating architecture in the regeneration site. The thickness of the trabecular (subchondral) bone was improved in all groups from 6 to 12 weeks. Histologically, remarkable differences in the cartilage regeneration were visible. At week 6, compared with SED groups, the TRE groups manifested modest inflammatory cells with pro-inflammatory cytokines (i.e., TNF-α and IL-6), improved collagen alignment and higher glycosaminoglycan (GAG) content, particularly in the PGI-TRE group. At week 12, the PGI-TRE group had the best regeneration outcomes, showing the formation of hyaline-like cartilage, the development of columnar rounded chondrocytes that expressed enriched levels of collagen type II and GAG, and functionalized trabecular bone with osteocytes. In summary, the combination of implanting cell-free PLGA and performing an early loading exercise can significantly promote the full

  17. 含有天然钙化软骨层骨软骨支架的研制%Fabrication of osteochondral scaffolds containing calcified cartilage zone

    Institute of Scientific and Technical Information of China (English)

    刘清宇; 王富友; 刘俊利; 孙欣慰; 杨柳

    2014-01-01

    Objective To establish osteochondral scaffolds with remained calcified cartilage zone for finding an ideal scaffold for tissue engineered repair of osteochondral defect.Methods Cartilage zone was harvested from fresh adult porcine knee to fabricate type Ⅱ collagen hydrogel.Bone blocks measuring 8 mm in diameter with calcified cartilage zone were prepared by trephine and acellular treatment was performed.Histological staining was used to identify complete removal of cells.To fabricate the osteochondral models containing calcified cartilage zone,type Ⅱ collagen was seeded onto the acellular bone blocks with calcified cartilage zone,lyophilized,and cross-linked with 10 g/L of genipin ethanol solution.Then cell seeding and scanning electron microscope were performed after the models were established.Results HE staining,toluidine blue staining,solid green staining,safranin O staining,and DAPI staining showed cells were completely removed from bone blocks by decellularized process.Porosity of type Ⅱ collagen sponge was (91.1 ±3.8) % and pore size was (79.7 ± 17.1) μm.Porosity of acellular bone blocks was (73.5 ±2.6)% and pore size was (470.2 ± 158.8) μm.Cells seeded onto osteochondral scaffolds grew well by scanning electron microscope.Conclusion Osteochondral scaffolds with calcified cartilage zone provide good biocompatibility and suitable pore size and porosity and may be an ideal material for repairing osteochondral defect in tissue engineering.%目的 构建含有天然钙化层结构的骨软骨支架,为组织工程修复骨软骨缺损提供一种理想的支架材料. 方法 选择新鲜成年猪膝关节为制备原料,切取软骨层用以制备Ⅱ型胶原水凝胶;环钻钻取直径8 mm包含天然钙化层结构的骨柱,进行脱细胞处理,组织学切片染色观察脱细胞情况;将Ⅱ型胶原水凝胶接种于含天然钙化层结构脱细胞骨柱上,冻干,10/L京尼平乙醇溶液交联,即得含天然钙化层结构的骨软骨

  18. Cochlear Implant in Adults

    Directory of Open Access Journals (Sweden)

    Jaleh Samadi

    2003-09-01

    Full Text Available Cochlear implant is the result of a great combination and collaboration of engineering and medicine. It is mainly because it has the most conflict with the human nervous system among all prosthesis. Cochlear implant helps a child with profound hearing loss to understand and articulate speech and let an adult person with hearing loss communicate with people by phone. Although these wonderful results could not be seen in all patients, will let us know about the great scientific findings.

  19. Anodized dental implant surface

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Mishra

    2017-01-01

    Full Text Available Purpose: Anodized implants with moderately rough surface were introduced around 2000. Whether these implants enhanced biologic effect to improve the environment for better osseointegration was unclear. The purpose of this article was to review the literature available on anodized surface in terms of their clinical success rate and bone response in patients till now. Materials and Methods: A broad electronic search of MEDLINE and PubMed databases was performed. A focus was made on peer-reviewed dental journals. Only articles related to anodized implants were included. Both animal and human studies were included. Results: The initial search of articles resulted in 581 articles on anodized implants. The initial screening of titles and abstracts resulted in 112 full-text papers; 40 animal studies, 16 studies on cell adhesion and bacterial adhesion onto anodized surfaced implants, and 47 human studies were included. Nine studies, which do not fulfill the inclusion criteria, were excluded. Conclusions: The long-term studies on anodized surface implants do favor the surface, but in most of the studies, anodized surface is compared with that of machined surface, but not with other surfaces commercially available. Anodized surface in terms of clinical success rate in cases of compromised bone and immediately extracted sockets has shown favorable success.

  20. Biomaterials in cochlear implants

    Directory of Open Access Journals (Sweden)

    Lenarz, Thomas

    2009-01-01

    Full Text Available The cochlear implant (CI represents, for almost 25 years now, the gold standard in the treatment of children born deaf and for postlingually deafened adults. These devices thus constitute the greatest success story in the field of ‘neurobionic’ prostheses. Their (now routine fitting in adults, and especially in young children and even babies, places exacting demands on these implants, particularly with regard to the biocompatibility of a CI’s surface components. Furthermore, certain parts of the implant face considerable mechanical challenges, such as the need for the electrode array to be flexible and resistant to breakage, and for the implant casing to be able to withstand external forces. As these implants are in the immediate vicinity of the middle-ear mucosa and of the junction to the perilymph of the cochlea, the risk exists – at least in principle – that bacteria may spread along the electrode array into the cochlea. The wide-ranging requirements made of the CI in terms of biocompatibility and the electrode mechanism mean that there is still further scope – despite the fact that CIs are already technically highly sophisticated – for ongoing improvements to the properties of these implants and their constituent materials, thus enhancing the effectiveness of these devices. This paper will therefore discuss fundamental material aspects of CIs as well as the potential for their future development.

  1. Anodized dental implant surface.

    Science.gov (United States)

    Mishra, Sunil Kumar; Kumar, Muktadar Anand; Chowdhary, Ramesh

    2017-01-01

    Anodized implants with moderately rough surface were introduced around 2000. Whether these implants enhanced biologic effect to improve the environment for better osseointegration was unclear. The purpose of this article was to review the literature available on anodized surface in terms of their clinical success rate and bone response in patients till now. A broad electronic search of MEDLINE and PubMed databases was performed. A focus was made on peer-reviewed dental journals. Only articles related to anodized implants were included. Both animal and human studies were included. The initial search of articles resulted in 581 articles on anodized implants. The initial screening of titles and abstracts resulted in 112 full-text papers; 40 animal studies, 16 studies on cell adhesion and bacterial adhesion onto anodized surfaced implants, and 47 human studies were included. Nine studies, which do not fulfill the inclusion criteria, were excluded. The long-term studies on anodized surface implants do favor the surface, but in most of the studies, anodized surface is compared with that of machined surface, but not with other surfaces commercially available. Anodized surface in terms of clinical success rate in cases of compromised bone and immediately extracted sockets has shown favorable success.

  2. Contraceptive implants: current perspectives

    Directory of Open Access Journals (Sweden)

    Rowlands S

    2014-09-01

    Full Text Available Sam Rowlands,1,2 Stephen Searle3 1Centre of Postgraduate Medical Research and Education, School of Health and Social Care, Bournemouth University, Bournemouth, United Kingdom; 2Dorset HealthCare, Bournemouth, United Kingdom; 3Sexual Health Services, Chesterfield, United KingdomAbstract: Progestin-only contraceptive implants are a highly cost-effective form of long-acting reversible contraception. They are the most effective reversible contraceptives and are of a similar effectiveness to sterilization. Pregnancies are rare in women using this method of contraception, and those that do occur must be fully investigated, with an ultrasound scan of the arm and serum etonogestrel level if the implant cannot be located. There are very few contraindications to use of implants, and they have an excellent safety profile. Both acceptability and continuation with the method are high. Noncontraceptive benefits include improvements in dysmenorrhea, ovulatory pain, and endometriosis. Problematic bleeding is a relatively common adverse effect that must be covered in preinsertion information-giving and supported adequately if it occurs. Recognized training for both insertion and removal should be undertaken. Care needs to be taken at both insertion and removal to avoid neurovascular injury. Implants should always be palpable; if they are not, noninsertion should be assumed until disproven. Etonogestrel implants are now radiopaque, which aids localization. Anticipated difficult removals should be performed by specially trained experts. Keywords: contraceptive, subdermal implant, etonogestrel, levonorgestrel, progestin-only, long-acting reversible contraception

  3. Biocompatible implant surface treatments.

    Science.gov (United States)

    Pattanaik, Bikash; Pawar, Sudhir; Pattanaik, Seema

    2012-01-01

    Surface plays a crucial role in biological interactions. Surface treatments have been applied to metallic biomaterials in order to improve their wear properties, corrosion resistance, and biocompatibility. A systematic review was performed on studies investigating the effects of implant surface treatments on biocompatibility. We searched the literature using PubMed, electronic databases from 1990 to 2009. Key words such as implant surface topography, surface roughness, surface treatment, surface characteristics, and surface coatings were used. The search was restricted to English language articles published from 1990 to December 2009. Additionally, a manual search in the major dental implant journals was performed. When considering studies, clinical studies were preferred followed by histological human studies, animal studies, and in vitro studies. A total of 115 articles were selected after elimination: clinical studies, 24; human histomorphometric studies, 11; animal histomorphometric studies, 46; in vitro studies, 34. The following observations were made in this review: · The focus has shifted from surface roughness to surface chemistry and a combination of chemical manipulations on the porous structure. More investigations are done regarding surface coatings. · Bone response to almost all the surface treatments was favorable. · Future trend is focused on the development of osteogenic implant surfaces. Limitation of this study is that we tried to give a broader overview related to implant surface treatments. It does not give any conclusion regarding the best biocompatible implant surface treatment investigated till date. Unfortunately, the eventually selected studies were too heterogeneous for inference of data.

  4. Treatment of Knee Osteochondral Lesions Using a Novel Clot of Autologous Plasma Rich in Growth Factors Mixed with Healthy Hyaline Cartilage Chips and Intra-Articular Injection of PRGF.

    Science.gov (United States)

    Cugat, Ramón; Alentorn-Geli, Eduard; Steinbacher, Gilbert; Álvarez-Díaz, Pedro; Cuscó, Xavier; Seijas, Roberto; Barastegui, David; Navarro, Jordi; Laiz, Patricia; García-Balletbó, Montserrat

    2017-01-01

    Knee cartilage or osteochondral lesions are common and challenging injuries. To date, most symptomatic lesions warrant surgical treatment. We present two cases of patients with knee osteochondral defects treated with a one-step surgical procedure consisting of an autologous-based matrix composed of healthy hyaline cartilage chips, mixed plasma poor-rich in platelets clot, and plasma rich in growth factors (PRGF). Both patients returned to playing soccer at the preinjury activity level and demonstrated excellent defect filling in both magnetic resonance imaging and second-look arthroscopy (in one of them). The use of a clot of autologous plasma poor in platelets with healthy hyaline cartilage chips and intra-articular injection of plasma rich in platelets is an effective, easy, and cheap option to treat knee cartilage injuries in young and athletic patients.

  5. The use of osteochondral allograft with bone marrow-derived mesenchymal cells and hinge joint distraction in the treatment of post-collapse stage of osteonecrosis of the femoral head.

    Science.gov (United States)

    Gagala, J; Tarczynska, M; Gaweda, K; Matuszewski, L

    2014-09-01

    Osteonecrosis of the femoral head is an entity which occurs mainly in young and active patients aged between 20 and 50. The success of hip joint preserving treatments ranges from 15% to 50% depending on the stage and amount of osteonecrotic lesion. Total hip replacement is indicated in late post-collapse hips but it has unsatisfactory survival because of the wear and osteolysis in young and active patients. Osteochondral allografts have been reported in the treatment of large articular lesions with defects in underlying bone in knee, talus and shoulder. By combining osteoconductive properties of osteochondral allograft with osteogenic abilities of bone marrow-derived mesenchymal cells it has a potential to be an alternative to an autologous graft. The adjunct of hinged joint distraction should minimize stresses in subchondral bone to promote creeping substitution and prevent femoral head collapse. Unlike current treatment modalities, it would provide both structural support and allow bony and articular substitution.

  6. Biphasic euchromatin-to-heterochromatin transition on the KSHV genome following de novo infection.

    Directory of Open Access Journals (Sweden)

    Zsolt Toth

    Full Text Available The establishment of latency is an essential step for the life-long persistent infection and pathogenesis of Kaposi's sarcoma-associated herpesvirus (KSHV. While the KSHV genome is chromatin-free in the virions, the viral DNA in latently infected cells has a chromatin structure with activating and repressive histone modifications that promote latent gene expression but suppress lytic gene expression. Here, we report a comprehensive epigenetic study of the recruitment of chromatin regulatory factors onto the KSHV genome during the pre-latency phase of KSHV infection. This demonstrates that the KSHV genome undergoes a biphasic chromatinization following de novo infection. Initially, a transcriptionally active chromatin (euchromatin, characterized by high levels of the H3K4me3 and acetylated H3K27 (H3K27ac activating histone marks, was deposited on the viral episome and accompanied by the transient induction of a limited number of lytic genes. Interestingly, temporary expression of the RTA protein facilitated the increase of H3K4me3 and H3K27ac occupancy on the KSHV episome during de novo infection. Between 24-72 hours post-infection, as the levels of these activating histone marks declined on the KSHV genome, the levels of the repressive H3K27me3 and H2AK119ub histone marks increased concomitantly with the decline of lytic gene expression. Importantly, this transition to heterochromatin was dependent on both Polycomb Repressive Complex 1 and 2. In contrast, upon infection of human gingiva-derived epithelial cells, the KSHV genome underwent a transcription-active euchromatinization, resulting in efficient lytic gene expression. Our data demonstrate that the KSHV genome undergoes a temporally-ordered biphasic euchromatin-to-heterochromatin transition in endothelial cells, leading to latent infection, whereas KSHV preferentially adopts a transcriptionally active euchromatin in oral epithelial cells, resulting in lytic gene expression. Our results

  7. Irradiation induces a biphasic expression of pro-inflammatory cytokines in the lung

    Energy Technology Data Exchange (ETDEWEB)

    Ruebe, C.E.; Wilfert, F.; Palm, J.; Burdak-Rothkamm, S.; Ruebe, C. [Dept. of Radiotherapy - Radiooncology, Saarland Univ., Homburg/Saar (Germany); Koenig, J. [Inst. of Medical Biometrics, Epidemiology and Medical Informatics, Saarland Univ., Homburg/Saar (Germany); Liu Li [Dept. of Radiotherapy - Radiooncology, Saarland Univ., Homburg/Saar (Germany); Cancer Center, Union Hospital Tongji Medical Coll., Huazhong Univ. of Science and Technology, Wuhan (China); Schuck, A.; Willich, N. [Dept. of Radiotherapy - Radiooncology, Univ. of Muenster (Germany)

    2004-07-01

    Background and purpose: the precise pathophysiological mechanisms of radiation-induced lung injury are poorly understood, but have been shown to correlate with dysregulation of different cytokines. The purpose of this study was to evaluate the time course of the pro-inflammatory cytokines tumor necrosis factor-(TNF-){alpha}, interleukin-(IL)-1{alpha} and IL-6 after whole-lung irradiation. Material and methods: the thoraces of C57BL/6J mice were irradiated with 12 Gy. Treated and control mice were sacrificed at 0.5, 1, 3, 6, 12, 24, 48, 72 h, 1, 2, 4, 8, 16, and 24 weeks post irradiation (p.i.). Real-time multiplex RT-PCR (reverse transcriptase polmyerase chain reaction) was established to evaluate the expression of TNF-{alpha}, IL-1{alpha} and IL-6 in the lung tissue of the mice. For histological analysis, lung tissue sections were stained by hematoxylin and eosin. Results: multiplex RT-PCR analysis revealed a biphasic expression of these pro-inflammatory cytokines in the lung tissue after irradiation. After an initial increase at 1 h p.i. for TNF-{alpha} and at 6 h p.i. for IL-1{alpha} and IL-6, the mRNA expression of these pro-inflammatory cytokines returned to basal levels (48 h, 72 h, 1 week, 2 weeks p.i.). During the pneumonic phase, TNF-{alpha}, IL-1{alpha} and IL-6 were significantly elevated and revealed their maximum at 8 weeks p.i. Histopathologic evaluation of the lung sections obtained within 4 weeks p.i. revealed only minor lung damage in 5-30% of the lung tissue. By contrast, at 8, 16, and 24 weeks p.i., 70-90% of the lung tissue revealed histopathologically detectable organizing alveolitis. Conclusion: irradiation induces a biphasic expression of pro-inflammatory cytokines in the lung. The initial transitory cytokine response occurred within the first hours after lung irradiation with no detectable histopathologic alterations. The second, more persistent cytokine elevation coincided with the onset of histologically discernible organizing acute

  8. Electrochemical assessment of water|ionic liquid biphasic systems towards cesium extraction from nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Stockmann, T. Jane [Laboratoire d’Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 6, Lausanne CH-1015 (Switzerland); Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7 (Canada); Zhang, Jing; Montgomery, Anne-Marie [Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7 (Canada); Ding, Zhifeng, E-mail: zfding@uwo.ca [Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7 (Canada)

    2014-04-01

    Highlights: • Electroanalytical chemistry was employed to assess cesium ion extraction in biphasic systems. • Water|ionic liquid systems are much more efficient than traditional water|organic ones. • The metal ion to ligand stoichiometry and overall complexation constant were determined. • The stoichiometry was confirmed by mass spectrometry. • The ligand CMPO used in TRUEX processes was found to be effective for the FIT. Abstract: A room temperature ionic liquid (IL) composed of a quaternary alkylphosphonium (trihexyltetradecylphosphonium, P66614⁺) and tetrakis(pentafluorophenyl)borate anion (TB⁻) was employed within a water|P66614TB (w|P66614TB or w|IL) biphasic system to evaluate cesium ion extraction in comparison to that with a traditional water|organic solvent (w|o) combination. ¹³⁷Cs is a major contributor to the radioactivity of spent nuclear fuel as it leaves the reactor, and its extraction efficiency is therefore of considerable importance. The extraction was facilitated by the ligand octyl(phenyl)-N,N'-diisobutylcarbamoylphosphine oxide (CMPO) used in TRans-Uranium EXtraction processes and investigated through well established liquid|liquid electrochemistry. This study gave access to the metal ion to ligand (1:n) stoichiometry and overall complexation constant, β, of the interfacial complexation reaction which were determined to be 1:3 and 1.6 × 10¹¹ at the w|P66614TB interface while the study at w|o elicited an n equal to 1 with β equal to 86.5. Through a straightforward relationship, these complexation constant values were converted to distribution coefficients, δα, with the ligand concentrations studied for comparison to other studies present in the literature; the w|o and w|IL systems gave δα of 2 and 8.2 × 10⁷, respectively, indicating a higher overall extraction efficiency for the latter. For the w|o system, the metal ion-ligand stoichiometries were

  9. Iatrogenic Tumor Implantation

    Institute of Scientific and Technical Information of China (English)

    Ying Ma; Ping Bai

    2008-01-01

    Iatrogenic tumor implantation is a condition that results from various medical procedures used during diagnosis or treatment of a malignancy. It involves desquamation and dissemination of tumor cells that develop into a local recurrence or distant metastasis from the tumor under treatment. The main clinical feature of the condition is nodules at the operation's porous channel or incision, which is easily diagnosed in accordance with the case history. Final diagnosis can be made based on pathological examination. Tumor implantation may occur in various puncturing porous channels, including a laparoscopic port, abdominal wall incision, and perineal incision, etc. Besides a malignant tumor,implantation potential exists with diseases, such as a borderline tumor and endometriosis etc. Once a tumor implantation is diagnosed, or suspected, surgical resection is usually conducted.During the diagnosis and treatment of diseases, avoiding and reducing iatrogenic implantation and dissemination has been regarded as an important principle for surgical treatment of tumors. In a clinical practice setting, if possible, excisional biopsy should be employed, if a biopsy is needed. Repeated puncturing should be avoided during a paracentesis. In a laparoscopic procedure, the tissue is first put into a sample bag and then is taken out from the point of incision. After a laparoscopic procedure, the peritoneum, abdominal muscular fasciae, and skin should be carefully closed, and/or the punctured porous channel be excised. In addition, the sample/tissue should be rinsed with distilled water before surgical closure of the abdominal cavity,allowing the exfoliated tumor cells to swell and rupture in the hypo-osmolar solution. Then surgical closure can be conducted following a change of gloves and equipment. The extent of hysteromyomectomy should as far as possible be away from the uterine cavity. The purpose of this study is to make clinicians aware of the possibility of tumor implantation

  10. Implant interactions with orthodontics.

    Science.gov (United States)

    Celenza, Frank

    2012-09-01

    Many situations arise in which orthodontic therapy in conjunction with implant modalities is beneficial, relevant or necessary. These situations might entail orthodontic treatment preparatory to the placement of an implant, such as in the site preparation for implant placement. Traditionally, this has been somewhat well understood, but there are certain guidelines that must be adhered to as well as diagnostic steps that must be followed. Provision of adequate space for implant placement is of paramount importance, but there is also the consideration of tissue manipulation and remodeling which orthodontic therapy can achieve very predictably and orthodontists should be well versed in harnessing and employing this modality of site preparation. In this way, hopeless teeth that are slated for extraction can still be utilized by orthodontic extraction to augment tissues, both hard and soft, thereby facilitating site development. On the corollary, and representing a significant shift in treatment sequencing, there are many situations in which orthodontic mechanotherapy can be simplified, expedited, and facilitated by the placement of an implant and utilization as an integral part of the mechanotherapy. Implants have proven to provide excellent anchorage, and have resulted in a new class of anchorage known as "absolute anchorage". Implants can be harnessed as anchors both in a direct and indirect sense, depending upon the dictates of the case. Further, this has led to the development of orthodontic miniscrew systems and techniques, which can have added features such as flexibility in location and placement, as well as ease of use and removal. As orthodontic appliances evolve, the advent of aligner therapy has become mainstream and well accepted, and many of the aforementioned combined treatment modalities can and should be incorporated into this relatively new treatment modality as well.

  11. Septic Encephalopathy Characterized by Acute Encephalopathy with Biphasic Seizures and Late Reduced Diffusion and Early Nonconvulsive Status Epilepticus

    Directory of Open Access Journals (Sweden)

    Hiroshi Yamaguchi

    2016-01-01

    Full Text Available Infection, whether viral or bacterial, can result in various forms of brain dysfunction (encephalopathy. Septic encephalopathy (SE is caused by an excessive immune reaction to infection, with clinical features including disturbed consciousness and seizures. Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD is usually accompanied by viral infection in children and is characterized by biphasic seizures and impaired consciousness. The initial neurologic symptom of AESD is typically a febrile seizure that frequently lasts longer than 30 minutes. However, the possible forms this seizure takes are unclear. For example, it is unknown if nonconvulsive status epilepticus (NCSE could be an early seizure symptomatic of AESD. In addition, thus far no cases of combined SE and AESD have been reported. Here, we describe the first reported case of SE with AESD that notably demonstrated NCSE as an early seizure.

  12. Modeling Diffusion Interaction in the bi-Phase Systems with Using Different Types of the Effective Kinetic Coefficients

    Directory of Open Access Journals (Sweden)

    L.I. Gladka

    2012-10-01

    Full Text Available The analysis of basic and combined models for calculation of effective kinetic coefficients required to describe diffusion processes in two-phase heterogeneous environments is conducted. For a transition zone that grows between two interacting diffusion phases was built a new model of effective medium. In this model the effective kinetic coefficient depends on the kinetic coefficients in each of the phases, volumetric particle phases and additional free parameter, which generally characterizes the type of structure of a bi-phase zone. It is shown that the combined model is constructed to describe the percolation behavior of effective medium. The phenomenological approach describes the formation and development of bi-phase zones in ternary systems which including streams through both phases and the analysis of the impact of the model on the resulting effective medium diffusion zone.

  13. Phosphorus-doped TiO2 catalysts with stable anatase-brookite biphase structure: synthesis and photocatalytic performance.

    Science.gov (United States)

    Feng, Huajun; Zhang, Min-Hong; Yu, Liya E

    2013-07-01

    Phosphorus-doped (P-doped) TiO2 catalysts with a stable anatase-brookite biphase structure were successfully synthesized by integrating ultrasonication with phosphorus doping and Pluronic P123 surfactant. The synthesized catalysts were characterized using X-ray diffraction, transmission electron microscopy, nitrogen adsorption-desorption, Fourier transform infrared, and UV-visible diffuse reflectance spectra. Ultrasonication facilitates the appearance of brookite phase. Phosphorus doping was demonstrated an effective strategy to stabilize the anatase-brookite biphase structure and inhibits undesirable grain growth. Triblock copolymer Pluronic P123 used in the reaction facilitates the formation of catalyst particles with mesoporous structure and large surface area and prevents particles from agglomeration. The low band-gap of brookite phase enables the synthesized P-doped TiO2 catalysts outperform commercial P25 TiO2 and N-doped TiO2 in the degradation of methylene blue under both solar light and visible light irradiation.

  14. 4-(Benzylamino)formoyldiphenylammonium Triflate (BDPAT):An Efficient, Recoverable Biphasic Catalyst For Esterification of Carboxylic Acids with Equimolar Amounts of Alcohols

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Esterification of carboxylic acid with equimolar amounts alcohol can be efficiently catalyzed by biphasic 4-(benzylamino)formoyldiphenylammonium triflate (BDPAT, 3) in good yield. The catalyst can be easily recovered without loss of activity.

  15. Biventricular takotsubo cardiomyopathy in an elderly woman with uncontrolled type 2 diabetes: the biphasic echocardiographic and clinical pattern.

    Science.gov (United States)

    Kochanowski, Janusz; Piatkowski, Radoslaw; Budnik, Monika; Jasik, Mariusz; Roik, Marek; Opolski, Grzegorz

    2016-12-01

    We describe a case of an elderly woman who was diagnosed with a biventricular takotsubo cardiomyopathy (TTC) with combination of emotional stress and poorly controlled type 2 diabetes. We observed significant correlation between biphasic improvement of right (after 4 days) and left ventricle function (after 4 weeks) with normalization glycemic status. To our knowledge, this is the first reported case in the literature of biventricular TTC with such metabolic disturbances.

  16. Hierarchical Fabrication of Engineered Vascularized Bone Biphasic Constructs via Dual 3D Bioprinting: Integrating Regional Bioactive Factors into Architectural Design.

    Science.gov (United States)

    Cui, Haitao; Zhu, Wei; Nowicki, Margaret; Zhou, Xuan; Khademhosseini, Ali; Zhang, Lijie Grace

    2016-09-01

    A biphasic artificial vascularized bone construct with regional bioactive factors is presented using dual 3D bioprinting platform technique, thereby forming a large functional bone grafts with organized vascular networks. Biocompatible mussel-inspired chemistry and "thiol-ene" click reaction are used to regionally immobilize bioactive factors during construct fabrication for modulating or improving cellular events. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Effects of vestibular prosthesis electrode implantation and stimulation on hearing in rhesus monkeys.

    Science.gov (United States)

    Dai, Chenkai; Fridman, Gene Y; Della Santina, Charles C

    2011-07-01

    To investigate the effects of vestibular prosthesis electrode implantation and activation on hearing in rhesus monkeys, we measured auditory brainstem responses (ABR) and distortion product otoacoustic emissions (DPOAE) in four rhesus monkeys before and after unilateral implantation of vestibular prosthesis electrodes in each of 3 left semicircular canals (SCC). Each of the 3 left SCCs were implanted with electrodes via a transmastoid approach. Right ears, which served as controls, were not surgically manipulated. Hearing tests were conducted before implantation (BI) and then 4 weeks post-implantation both without electrical stimulation (NS) and with electrical stimulation (S). During the latter condition, prosthetic electrical stimuli encoding 3 dimensions of head angular velocity were delivered to the 3 ampullary branches of the left vestibular nerve via each of 3 electrode pairs of a multichannel vestibular prosthesis. Electrical stimuli comprised charge-balanced biphasic pulses at a baseline rate of 94 pulses/s, with pulse frequency modulated from 48 to 222 pulses/s by head angular velocity. ABR hearing thresholds to clicks and tone pips at 1, 2, and 4 kHz increased by 5-10 dB from BI to NS and increased another ∼5 dB from NS to S in implanted ears. No significant change was seen in right ears. DPOAE amplitudes decreased by 2-14 dB from BI to NS in implanted ears. There was a slight but insignificant decrease of DPOAE amplitude and a corresponding increase of DPOAE/Noise floor ratio between NS and S in implanted ears. Vestibular prosthesis electrode implantation and activation have small but measurable effects on hearing in rhesus monkeys. Coupled with the clinical observation that patients with cochlear implants only rarely exhibit signs of vestibular injury or spurious vestibular nerve stimulation, these results suggest that although implantation and activation of multichannel vestibular prosthesis electrodes in human will carry a risk of hearing loss

  18. Positron implantation in solids

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, V.J.; Lynn, K.G.; Welch, D.O.

    1993-12-31

    The Monte Carlo technique for modeling positron prior to annihilation and electron implantation in semi-infinite metals is described. Particle implantation is modelled as a multistep process, a series of collisions with the atoms of the host material. In elastic collisions with neutral atoms there is no transfer of energy. The particle loses energy by several different channels, excitation of the electron gas, ionization of the ion cores, or, at low energies, by phonon excitation. These competing scattering mechanisms have been incorporated into the Monte Carlo framework and several different models are being used. Brief descriptions of these Monte Carlo schemes, as well as an analytic model for positron implantation are included. Results of the Monte Carlo simulations are presented and compared with expermental data. Problems associated with modeling positron implantation are discuss and the need for more expermental data on energy-loss in different materials is stressed. Positron implantation in multilayers of different metals is briefly described and extensions of this work to include a study of multilayers and heterostructures is suggested.

  19. Usefulness of p16/CDKN2A fluorescence in situ hybridization and BAP1 immunohistochemistry for the diagnosis of biphasic mesothelioma.

    Science.gov (United States)

    Wu, Di; Hiroshima, Kenzo; Yusa, Toshikazu; Ozaki, Daisuke; Koh, Eitetsu; Sekine, Yasuo; Matsumoto, Shinji; Nabeshima, Kazuki; Sato, Ayuko; Tsujimura, Tohru; Yamakawa, Hisami; Tada, Yuji; Shimada, Hideaki; Tagawa, Masatoshi

    2017-02-01

    Malignant mesothelioma is a highly aggressive neoplasm, and the histologic subtype is one of the most reliable prognostic factors. Some biphasic mesotheliomas are difficult to distinguish from epithelioid mesotheliomas with atypical fibrous stroma. The aim of this study was to analyze p16/CDKN2A deletions in mesotheliomas by fluorescence in situ hybridization (FISH) and BAP1 immunohistochemistry to evaluate their potential role in the diagnosis of biphasic mesothelioma. We collected 38 cases of pleural mesotheliomas. The results of this study clearly distinguished 29 cases of biphasic mesothelioma from 9 cases of epithelioid mesothelioma. The proportion of biphasic mesotheliomas with homozygous deletions of p16/CDKN2A in total was 96.6% (28/29). Homozygous deletion of p16/CDKN2A was observed in 18 (94.7%) of 19 biphasic mesotheliomas with 100% concordance of the p16/CDKN2A deletion status between the epithelioid and sarcomatoid components in each case. Homozygous deletion of the p16/CDKN2A was observed in 7 (77.8%) of 9 epithelioid mesotheliomas but not in fibrous stroma. BAP1 loss was observed in 5 (38.5%) of 13 biphasic mesotheliomas and in both epithelioid and sarcomatoid components. BAP1 loss was observed in 5 (62.5%) of 8 epithelioid mesotheliomas but not in fibrous stroma. Homozygous deletion of p16/CDKN2A is common in biphasic mesotheliomas, and the analysis of only one component of mesothelioma is sufficient to show that the tumor is malignant. However, compared with histology alone, FISH analysis of the p16/CDKN2A status and BAP1 immunohistochemistry in the spindled mesothelium provide a more objective means to differentiate between biphasic mesothelioma and epithelioid mesothelioma with atypical stromal cells.

  20. Biphasic effects of acetylstrophanthidin on automaticity in guinea pig ventricular muscle.

    Science.gov (United States)

    Karagueuzian, H S; Katzung, B G

    1982-04-23

    The effects of acetylstrophanthidin (AS) on depolarization-induced automaticity and contractility of guinea pig papillary muscle were studied in a single sucrose gap chamber with microelectrode and current-clamp techniques. The concentration used, 1.4-1.8 microM, never induced automaticity in preparations at their normal resting potential. Twenty min after superfusion with AS, action potential duration (APD) was prolonged and the force of contraction increased. These were associated with an increase in slope of phase 4 depolarization and an increase in the membrane resistance (Rm) of muscles depolarized with small constant current pulses. With longer (50-80 min) periods of AS superfusion, APD became shorter, Rm decreased to less than predrug values, and in depolarized preparations, the slope of phase 4 decreased. Contractility remained unchanged throughout this second phase. All of these effects were fully reversible upon 60 min of superfusion with AS-free Tyrode solution. We suggest that the biphasic effects of AS on the automaticity of depolarized ventricular muscle cells are caused by an initial decrease followed by a later increase in transmembrane potassium conductance.

  1. Preparation, characterization and in vitro dissolution behavior of porous biphasic α/β-tricalcium phosphate bioceramics.

    Science.gov (United States)

    Xie, Lu; Yu, Haiyang; Deng, Yi; Yang, Weizhong; Liao, Li; Long, Qin

    2016-02-01

    The ideal bone tissue engineering scaffolds are long-cherished with the properties of interconnected macroporous structures, adjustable degradation and excellent biocompatibility. Here, a series of porous α/β-tricalcium phosphate (α/β-TCP) biphasic bioceramics with different phase ratios of α-TCP and β-TCP were successfully synthesized by heating an amorphous calcium phosphate precursor. The chemical and morphological characterization showed that α- and β-TCP phases co-existed in the α/β-TCP bioceramics and they had interconnected pore structures with size between 200 and 500μm. The in vitro dissolution behavior and bioactivity of the dual α/β-TCP were also probed in static and dynamic SBF for the first time. The results revealed that α/β-TCP scaffolds had good in vitro bioactivity, as the formation of bone-like apatite layers was induced on the scaffolds after mineralization in SBF. Moreover, dissolution rate of α/β-TCP bioceramics in dynamic environment was higher than that under static condition. Compared with monophasic TCP ceramics, these porous α/β-TCP bioceramics displayed a tailored dissolution rate proportionate to the TCP content (α and β) in the materials. Further, the degradation profile of porous α/β-TCP was well-described by Avrami equation. The porous dual α/β-TCP bioceramics with controllable degradation behavior hold great potential to be applied in bone tissue engineering as bone substitutes.

  2. Nanoscopic characterization of the water vapor-salt interfacial layer reveals a unique biphasic adsorption process.

    Science.gov (United States)

    Yang, Liu; He, Jianfeng; Shen, Yi; Li, Xiaowei; Sun, Jielin; Czajkowsky, Daniel M; Shao, Zhifeng

    2016-08-16

    Our quantitative understanding of water adsorption onto salt surfaces under ambient conditions is presently quite poor owing to the difficulties in directly characterizing this interfacial layer under these conditions. Here we determine the thickness of the interfacial layer on NaCl at different relative humidities (RH) based on a novel application of atomic force spectroscopy and capillary condensation theory. In particular, we take advantage of the microsecond-timescale of the capillary condensation process to directly resolve the magnitude of its contribution in the tip-sample interaction, from which the interfacial water thickness is determined. Further, to correlate this thickness with salt dissolution, we also measure surface conductance under similar conditions. We find that below 30% RH, there is essentially only the deposition of water molecules onto this surface, typical of conventional adsorption onto solid surfaces. However, above 30% RH, adsorption is simultaneous with the dissolution of ions, unlike conventional adsorption, leading to a rapid increase of surface conductance. Thus, water adsorption on NaCl is an unconventional biphasic process in which the interfacial layer not only exhibits quantitative differences in thickness but also qualitative differences in composition.

  3. Biphasic Regulation of Lipid Metabolism: A Meta-Analysis of Icodextrin in Peritoneal Dialysis.

    Science.gov (United States)

    Huang, Yan-Feng; Zhu, Da-Jian; Chen, Xiao-Wu; Ouyang, Man-Zhao; Zhang, Wei-Jie

    2015-01-01

    The objective of this systematic meta-analysis was to study the impact of icodextrin (ICO) on lipid profiles. MEDLINE, PubMed, Embase, Chinese Biomedical Literature, and the Cochrane Library and Reference lists were searched (last search September 2014) in accordance with the Cochrane Handbook for Systematic Reviews of Interventions. Searches identified 13 eligible trials with a total of 850 patients. The differentials of total cholesterol (TC) and free fatty acid (FFA) in the ICO group were greater than those in the GLU group. Metaregression analysis showed that TC levels positively correlated with its baseline levels. In the subgroup of patients with dialysis duration more than 6 months, TC and TG in the ICO group were less. In pooled data from cross-sectional studies, differential of TG in the ICO group was less. In the subgroup of patients with diabetes (Martikainen et al., 2005, Sniderman et al., 2014, and Takatori et al., 2011), differential of high-density lipoprotein cholesterol (HDL-C) in the ICO group was less. There was no significant effect on low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), or lipoprotein(a). ICO may be beneficial to lipid metabolism, especially for its biphasic regulation of plasma TC levels.

  4. Biphasic Regulation of Lipid Metabolism: A Meta-Analysis of Icodextrin in Peritoneal Dialysis

    Directory of Open Access Journals (Sweden)

    Yan-Feng Huang

    2015-01-01

    Full Text Available Objectives. The objective of this systematic meta-analysis was to study the impact of icodextrin (ICO on lipid profiles. Methods. MEDLINE, PubMed, Embase, Chinese Biomedical Literature, and the Cochrane Library and Reference lists were searched (last search September 2014 in accordance with the Cochrane Handbook for Systematic Reviews of Interventions. Results. Searches identified 13 eligible trials with a total of 850 patients. The differentials of total cholesterol (TC and free fatty acid (FFA in the ICO group were greater than those in the GLU group. Metaregression analysis showed that TC levels positively correlated with its baseline levels. In the subgroup of patients with dialysis duration more than 6 months, TC and TG in the ICO group were less. In pooled data from cross-sectional studies, differential of TG in the ICO group was less. In the subgroup of patients with diabetes (Martikainen et al., 2005, Sniderman et al., 2014, and Takatori et al., 2011, differential of high-density lipoprotein cholesterol (HDL-C in the ICO group was less. There was no significant effect on low-density lipoprotein cholesterol (LDL-C, very low-density lipoprotein cholesterol (VLDL-C, or lipoprotein(a. Conclusions. ICO may be beneficial to lipid metabolism, especially for its biphasic regulation of plasma TC levels.

  5. Enhanced tunability afforded by aqueous biphasic systems formed by fluorinated ionic liquids and carbohydrates†

    Science.gov (United States)

    Boal-Palheiros, Isabel; Pereiro, Ana B.; Rebelo, Luís Paulo N.; Freire, Mara G.

    2016-01-01

    This work unveils the formation of novel aqueous biphasic systems (ABS) formed by perfluoroalkylsulfonate-based ionic liquids (ILs) and a large number of carbohydrates (monosaccharides, disaccharides and polyols) aiming at establishing more benign alternatives to the salts commonly used. The respective ternary phase diagrams were determined at 298 K. The aptitude of the carbohydrates to induce phase separation closely follows their hydration capability, while the length of the IL cation/anion fluorinated chain also plays a crucial role. Finally, these systems were investigated as liquid–liquid extraction strategies for four food dyes. Single-step extraction efficiencies for the carbohydrate-rich phase up to 94% were obtained. Remarkably and contrarily to the most investigated IL-salt ABS, most dyes preferentially migrate for the most hydrophilic and biocompatible carbohydrate-rich phase – an outstanding advantage when envisaging the products recovery and further use. On the other hand, more hydrophobic dyes preferentially partition to the IL-rich phase, disclosing therefore these novel systems as highly amenable to be tuned by the proper choice of the phase-forming components. PMID:27667966

  6. Work Stress and Alcohol Use: Developing and Testing a Biphasic Self-Medication Model.

    Science.gov (United States)

    Frone, Michael R

    2016-01-01

    This study developed and tested a moderated-mediation model of work stress and alcohol use, based on the biphasic (stimulant and sedative) effects of alcohol and the self-medication and stress-vulnerability models of alcohol use. The model proposes that exposure to work stressors can increase both negative affect and work fatigue, and that these two sources of strain can subsequently motivate the use of alcohol. However, the relations of negative affect and work fatigue to alcohol use are conditional on the joint moderating effects of alcohol outcome expectancies and gender. Data were collected from a national probability sample of 2,808 U.S. workers. Supporting the model, the results indicated that work stressor exposure was conditionally related via negative affect to heavy alcohol use among both men and women holding strong tension reduction alcohol expectancies and to after work alcohol use among men holding strong tension reduction alcohol expectancies. Also, work stressor exposure was conditionally related via work fatigue to both heavy alcohol use and workday alcohol use among men holding strong fatigue reduction alcohol expectancies. The results have application in the identification of individuals at higher risk of problematic alcohol use and are relevant to workplace safety and to the design of appropriate interventions.

  7. Synthesis, characterization and in vitro study of magnetic biphasic calcium sulfate-bioactive glass

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Yi-Fan; Akram, Muhammad; Alshemary, Ammar Z. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Darul Ta' zim (Malaysia); Hussain, Rafaqat, E-mail: rafaqat@kimia.fs.utm.my [Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor Darul Ta' zim (Malaysia)

    2015-08-01

    Calcium sulfate-bioactive glass (CSBG) composites doped with 5, 10 and 20 mol% Fe were synthesized using quick alkali sol–gel method. X-ray diffraction (XRD) data of samples heated at 700 °C revealed the presence of anhydrite, while field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) characterization confirmed the formation of nano-sized CSBGs. The UV–vis studies confirmed that the main iron species in 5% Fe and 10% Fe doped CSBGs were tetrahedral Fe(III) whereas that in 20% Fe doped CSBG were extra-framework FeO{sub x} oligomers or iron oxide phases. Measurement of magnetic properties of the samples by vibrating sample magnetometer (VSM) showed very narrow hysteresis loop with zero coercivity and remanence for 10% Fe and 20% Fe doped CSBG, indicating that they are superparamagnetic in nature. All samples induced the formation of apatite layer with Ca/P ratio close to the stoichiometric HA in simulated body fluid (SBF) assessment. - Highlights: • Biphasic calcium sulphate-bioactive glass containing iron was prepared. • Composite bioglass was superparamagnetic in nature. • All samples promoted the growth of apatite layer with Ca/P close to 1.67.

  8. Biphasic effect of aspirin on apoptosis of bovine vascular endothelial cells and its molecular mechanism

    Institute of Scientific and Technical Information of China (English)

    Qing-quan CHEN; Wen-lan LIU; Xun GUO; Yuan-jian LI; Zhao-gui GUO

    2007-01-01

    Aim: To investigate the effect of aspirin on the apoptosis of cultured bovine aortic endothelial cells (BAEC) and the signal pathways involved in this process.Methods: BAEC were cultured and passaged in Dulbecco's modified Eagle's medium culture medium. Morphologic changes and quantification of apoptotic cells were determined using fluorescence microscope after staining the cells with Hoechst 33258. Cell viability was measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) method. DNA fragmentation was visualized by agarose gel electrophoresis. Phospho-p38 mitogen-activated protein kinase(MAPK) expression was detected by Western blotting. Results: Aspirin at low concentrations from 1×10-10 mol/L to 1×10-8 mol/L decreased the apoptosis and p38 MAPK phosphorylation induced by H2O2 in BAEC, while high doses of aspi-fin (1×10-7-1×10-4 mol/L) induced typical apoptotic changes in BAEC and stimu-lated the expression of phospho-p38 MAPK in a concentration-dependent manner.SB203580, a specific p38 MAPK inhibitor, blocked such effects. Conclusion:Aspirin exhibits a biphasic effect on the apoptosis in BAEC, reducing apoptosis at low concentration and inducing apoptosis at high concentration, p38 MAPK may be an important signal molecule mediating the effects of aspirin.

  9. Response of the Hodgkin-Huxley neuron to a periodic sequence of biphasic pulses

    CERN Document Server

    Borkowski, L S

    2013-01-01

    We study the response of the Hodgkin-Huxley neuron stimulated periodically by biphasic rectangular current pulses. The optimal response for charge-balanced input is obtained for cathodic-first pulses with an inter-phase gap (IPG) approximately equal 5 ms. For short pulses the topology of the global bifurcation diagram in the period-amplitude plane is approximately invariant with respect to the pulse polarity and shape details. If stimuli are delivered at neuron's resonant frequencies the firing rate is a continuous function of pulse amplitude. At nonresonant frequencies the quiescent state and the firing state coexist over a range of amplitude values and the transition to excitability is a discontinuous one. There is a multimodal odd-all transition between the 2:1 and 3:1 locked-in states. A strong antiresonant effect is found between the states 3:1 and 4:1, where the modes (2+3n):1, $n=0,1,2,...$, are entirely absent. At high frequencies the excitation threshold is a nonmonotonic function of the stimulus and...

  10. Biphasic synovial sarcoma in a 19-year-old pregnant woman: a case report.

    Science.gov (United States)

    Adameşteanu, Mădălina Olivia; Scurtu, Răzvan; Lascăr, Ioan; Vâlcu, Marek; Popescu, Şerban Arghir; Sebe, Ioana Teona

    2015-01-01

    Synovial sarcoma is a rare malignant tumor of mesenchymal multipotent cells. We hereby present a case of synovial sarcoma of the upper left thigh. A 19-year-old patient was referred to our clinic by another hospital in Bucharest, Romania, for a soft tissue mass in the left upper thigh. Local examination of the left thigh revealed a 15÷13 cm, ovoid, painful upon touch, soft tissue mass occupying the proximal-medial aspect of the thigh. Bilateral inguinal nodes' enlargement was noticed. Upon suspecting regional node involvement, the surgical team decided to perform left limb amputation due to tumor size and the proximity to major arterial and nervous trunks as well as the femoral shaft, making curative surgery and 'free of disease' resection margins improbable. The patient refused the operation. The surgical team (plastic surgeon, orthopedic surgeon) decided to attempt limb-sparing surgery. After tumor resection, free-of-disease surgical margins were achieved. The pathological examination as well as the immunohistochemistry (IHC) diagnosed a large biphasic synovial sarcoma warranting oncologic treatment. The association between tumor growth and pregnancy poses important therapeutic problems, such as the use of preoperative chemotherapy, potential pregnancy termination, limb amputation versus limb salvage intervention and types of protocols of chemotherapy or radiotherapy indicated.

  11. Biphasic threat to femoral head perfusion in abduction: arterial hypoperfusion and venous congestion

    Energy Technology Data Exchange (ETDEWEB)

    Yousefzadeh, David K. [Comer Children' s Hospital, Department of Radiology, Chicago, IL (United States); University of Chicago, Department of Radiology, Chicago, IL (United States); Jaramillo, Diego [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); Johnson, Neil [Cincinnati Children' s Hospital, Department of Radiology, Cincinnati, OH (United States); Doerger, Kirk [Radiology Associates of Northern Kentucky, Crestview Hills, KY (United States); Sullivan, Christopher [University of Chicago, Department of Surgery, Chicago, IL (United States)

    2010-09-15

    Hip abduction can cause avascular necrosis (AVN) of the femoral head in infants. To compare the US perfusion pattern of femoral head cartilage in neutral position with that in different degrees and duration of abduction, testing the venous congestion theory of post-abduction ischemia. In 20 neonates, the Doppler flow characteristics of the posterosuperior (PS) branch of the femoral head cartilage feeding vessels were evaluated in neutral and at 30 , 45 , and 60 abduction. In three neonates the leg was held in 45-degree abduction and flow was assessed at 5, 10, and 15 min. Male/female ratio was 11/9 with a mean age of 1.86 {+-} 0.7 weeks. The peak systolic velocities (PSV) declined in all three degrees of abduction. After 15 min of 45-degree abduction, the mean PSV declined and showed an absent or reversed diastolic component and undetectable venous return. No perfusion was detected at 60-degree abduction. Abduction-induced femoral head ischemia is biphasic and degree- and duration-dependent. In phase I there is arterial hypoperfusion and in phase II there is venous congestion. A new pathogeneses for femoral head ischemia is offered. (orig.)

  12. Striatal dopamine release and biphasic pattern of locomotor and motor activity under gas narcosis.

    Science.gov (United States)

    Balon, Norbert; Risso, Jean-Jacques; Blanc, François; Rostain, Jean-Claude; Weiss, Michel

    2003-05-02

    Inert gas narcosis is a neurological syndrome appearing when humans or animals are exposed to hyperbaric inert gases (nitrogen, argon) composed by motor and cognitive impairments. Inert gas narcosis induces a decrease of the dopamine release at the striatum level, structure involved in the regulation of the extrapyramidal motricity. We have investigated, in freely moving rats exposed to different narcotic conditions, the relationship between the locomotor and motor activity and the striatal dopamine release, using respectively a computerized device that enables a quantitative analysis of this behavioural disturbance and voltammetry. The use of 3 MPa of nitrogen, 2 MPa of argon and 0.1 MPa of nitrous oxide, revealed after a transient phase of hyperactivity, a lower level of the locomotor and motor activity, in relation with the decrease of the striatal dopamine release. It is concluded that the striatal dopamine decrease could be related to the decrease of the locomotor and motor hyperactivity, but that other(s) neurotransmitter(s) could be primarily involved in the behavioural motor disturbances induced by narcotics. This biphasic effect could be of major importance for future pharmacological investigations, and motor categorization, on the basic mechanisms of inert gas at pressure.

  13. A simple biphasic route to water soluble dithiocarbamate functionalized quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.; Xu, J.; Goodman, M.; Chen, Y.; Cai, M.; Shinar, J.; Lin, Z.

    2008-06-11

    Hydrophobic trioctylphosphine oxide-functionalized CdSe quantum dots (CdSe-TOPO QDs) were transferred from organic solvent to aqueous solution via a simple yet novel biphasic ligand exchange process in one step, which involved the in-situ formation of hydrophilic dithiocarbamate moieties and subsequent ligand exchange with TOPO at the chloroform/water interface. The resulting water dispersible, dithiocarbamate functionalized CdSe QDs (i.e., D-CdSe) exhibited an increased photoluminescence (PL) quantum yield as compared to the original CdSe-TOPO QDs, suggesting an effective passivation of dithiocarbamate ligands on the QD surface. The D-CdSe QDs were then mixed with hydroxyl terminated TiO{sub 2} nanoparticles. A decrease in the PL of the mixture was observed, indicating a possible charge transfer from the D-CdSe QDs to the TiO{sub 2} nanoparticles. The reaction of the carboxyl group on the D-CdSe surface with the hydroxyl group on the TiO{sub 2} rendered QDs in direct contact with TiO{sub 2}, thereby facilitating the electronic interaction between them.

  14. Histamine and spontaneous motor activity: biphasic changes, receptors involved and participation of the striatal dopamine system.

    Science.gov (United States)

    Chiavegatto, S; Nasello, A G; Bernardi, M M

    1998-01-01

    The time- and dose-related effects of exogenous histamine on spontaneous motor activity and receptors involved were evaluated in male rats. Intracerebroventricular administration of histamine (5.4 and 54.3 nmol) produced a biphasic effect with initial transitory hypoactivity and later hyperactivity expressed by locomotion frequency in an open-field. The rearing frequencies were only reduced by all doses of histamine used. The histamine-induced hypoactivity was inhibited by the H3-antagonist thioperamide and was also induced by the H3-agonist N-alpha-methylhistamine. The histamine-induced hyperactivity phase was blocked by the H1-antagonist mepyramine. The H2-antagonist ranitidine increased locomotion and rearing frequencies. The participation of other neurotransmitters in the persistent hypokinetic effect induced by 135.8 nmol of histamine was determined by HPLC in the striatum and hypothalamus as counter-proof. A decreased DOPAC/DA ratio was observed only in the striatum. In the hypothalamus, low levels of 5HT were detected, probably not correlated with motor activity. In conclusion, the present results suggest that the exogenous histamine-induced hypoactivity response is probably due to activation of H3-receptors as heteroreceptors reducing the activity of the striatal dopaminergic system. This effect can partially overlap with the expression of the hyperactivity induced by H1-receptor activation. The participation of H2-receptors requires further investigation.

  15. Biphasic changes in body temperature produced by intracerebroventricular injections of histamine in the cat.

    Science.gov (United States)

    Clark, W G; Cumby, H R

    1976-09-01

    1. Intracerebroventricular administration of histamine to cats caused hypothermia followed by a rise in body temperature. 2-Methylhistamine caused a similar biphasic response, while 3-methylhistamine had no effect on body temperature and 4-methylhistamine produced a delayed hyperthermia. Some tolerance to the hypothermic activity developed when a series of closely spaced injections of histamine was given. 2. Doses of histamine and 2-methylhistamine which altered body temperature when given centrally were ineffective when infused or injected I.V. 3. Pyrilamine, an H1-receptor antagonist, prevented the hypothermic response to histamine. 4. Hypothermic responses to histamine at an environmental temperature of 22 degrees C were comparable to responses in a cold room at 4 degrees C in both resting animals and animals acting to depress a lever to escape an external heat load. A change in error signal from the thermostat could account for these results. However, lesser degrees of hypothermia developed when histamine was given to animals in a hot environment. In some, but not all animals, this smaller response could be attributed to inadequate heat loss in spite of maximal activation of heat-loss mechanisms. 5. The hyperthermic response to histamine was antagonized by central, but not peripheral, injection of metiamide, an H2-receptor antagonist. 6. The results indicate that histamine and related agents can act centrally to cause both hypothermia, mediated by H1-receptors, and hyperthermia, mediated by H2-receptors.

  16. A flow reactor setup for photochemistry of biphasic gas/liquid reactions

    Directory of Open Access Journals (Sweden)

    Josef Schachtner

    2016-08-01

    Full Text Available A home-built microreactor system for light-mediated biphasic gas/liquid reactions was assembled from simple commercial components. This paper describes in full detail the nature and function of the required building elements, the assembly of parts, and the tuning and interdependencies of the most important reactor and reaction parameters. Unlike many commercial thin-film and microchannel reactors, the described set-up operates residence times of up to 30 min which cover the typical rates of many organic reactions. The tubular microreactor was successfully applied to the photooxygenation of hydrocarbons (Schenck ene reaction. Major emphasis was laid on the realization of a constant and highly reproducible gas/liquid slug flow and the effective illumination by an appropriate light source. The optimized set of conditions enabled the shortening of reaction times by more than 99% with equal chemoselectivities. The modular home-made flow reactor can serve as a prototype model for the continuous operation of various other reactions at light/liquid/gas interfaces in student, research, and industrial laboratories.

  17. A flow reactor setup for photochemistry of biphasic gas/liquid reactions.

    Science.gov (United States)

    Schachtner, Josef; Bayer, Patrick; Jacobi von Wangelin, Axel

    2016-01-01

    A home-built microreactor system for light-mediated biphasic gas/liquid reactions was assembled from simple commercial components. This paper describes in full detail the nature and function of the required building elements, the assembly of parts, and the tuning and interdependencies of the most important reactor and reaction parameters. Unlike many commercial thin-film and microchannel reactors, the described set-up operates residence times of up to 30 min which cover the typical rates of many organic reactions. The tubular microreactor was successfully applied to the photooxygenation of hydrocarbons (Schenck ene reaction). Major emphasis was laid on the realization of a constant and highly reproducible gas/liquid slug flow and the effective illumination by an appropriate light source. The optimized set of conditions enabled the shortening of reaction times by more than 99% with equal chemoselectivities. The modular home-made flow reactor can serve as a prototype model for the continuous operation of various other reactions at light/liquid/gas interfaces in student, research, and industrial laboratories.

  18. The smear layer created by scaling and root planing is physiologically eliminated in a biphasic process

    Directory of Open Access Journals (Sweden)

    Fernanda Regina Godoy ROCHA

    2015-01-01

    Full Text Available Mechanical instrumentation of the root surface causes the formation of a smear layer, which is a physical barrier that can affect periodontal regeneration. Although different procedures have been proposed to remove the smear layer, there is no information concerning how long the smear layer persists on root surfaces after instrumentation in vivo. This study assessed the presence of the smear layer on root surfaces over a 28-day period after subgingival instrumentation with hand instruments. Fifty human teeth that were referred for extraction because of advanced periodontal disease were scaled and root planed (SRP by a single experienced operator. Ten teeth were randomly assigned to be extracted 7, 14, 21, and 28 days after SRP. Another 10 teeth were extracted immediately after instrumentation (Day 0, control group. The subgingival area of the instrumented roots was evaluated with scanning electron microscopy. Representative photomicrographs were assessed by a blinded and calibrated examiner according to a scoring system. A rapid and significant (p < 0.05, Z test initial reduction in the amount of smear layer was observed at 7 days, and a further significant (p < 0.05 decrease was observed 28 days after SRP. Interestingly, even 28 days after SRP, the smear layer was still present on root surfaces. This study showed that the physiological elimination of the smear layer occurred in a biphasic manner: a rapid initial reduction was observed 7 days after instrumentation, which was followed by a slow process leading to a significant decrease 28 days after instrumentation.

  19. Liquid / liquid biphasic electrochemistry in ultra-turrax dispersed acetonitrile / aqueous electrolyte systems

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, John D. [Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom); Amemiya, Fumihiro; Atobe, Mahito [Tokyo Institute of Technology, Department of Electronic Chemistry, Yokohama, Kanagawa 2268502 (Japan); Bulman-Page, Philip C. [School of Chemistry, University of East Anglia, Norwich, Norfolk NR4 7TJ (United Kingdom); Marken, Frank, E-mail: F.Marken@bath.ac.u [Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY (United Kingdom)

    2010-12-01

    Unstable acetonitrile | aqueous emulsions generated in situ with ultra-turrax agitation are investigated for applications in dual-phase electrochemistry. Three modes of operation for liquid / liquid aqueous-organic electrochemical processes are demonstrated with no intentionally added electrolyte in the organic phase based on (i) the formation of a water-soluble product in the aqueous phase in the presence of the organic phase, (ii) the formation of a product and ion transfer at the liquid / liquid-electrode triple phase boundary, and (iii) the formation of a water-insoluble product in the aqueous phase which then transfers into the organic phase. A three-electrode electrolysis cell with ultra-turrax agitator is employed and characterised for acetonitrile / aqueous 2 M NaCl two phase electrolyte. Three redox systems are employed in order to quantify the electrolysis cell performance. The one-electron reduction of Ru(NH{sub 3}){sub 6}{sup 3+} in the aqueous phase is employed to determine the rate of mass transport towards the electrode surface and the effect of the presence of the acetonitrile phase. The one-electron oxidation of n-butylferrocene in acetonitrile is employed to study triple phase boundary processes. Finally, the one-electron reduction of cobalticenium cations in the aqueous phase is employed to demonstrate the product transfer from the electrode surface into the organic phase. Potential applications in biphasic electrosynthesis are discussed.

  20. Biphasic products of dicalcium phosphate-rich cement with injectability and nondispersibility.

    Science.gov (United States)

    Ko, Chia-Ling; Chen, Jian-Chih; Hung, Chun-Cheng; Wang, Jen-Chyan; Tien, Yin-Chun; Chen, Wen-Cheng

    2014-06-01

    In this study, a calcium phosphate cement was developed using tetracalcium phosphate and surface-modified dicalcium phosphate anhydrous (DCPA). This developed injectable bone graft substitute can be molded to the shape of the bone cavity and set in situ through the piping system that has an adequate mechanical strength, non-dispersibility, and biocompatibility. The materials were based on the modified DCPA compositions of calcium phosphate cement (CPC), where the phase ratio of the surface-modified DCPA is higher than that of the conventional CPC for forming dicalcium phosphate (DCP)-rich cement. The composition and morphology of several calcium phosphate cement specimens during setting were analyzed via X-ray diffractometry and transmission electron microscopy coupled with an energy dispersive spectroscopy system. The compressive strength of DCP-rich CPCs was greater than 30MPa after 24h of immersion in vitro. The reaction of the CPCs produced steady final biphasic products of DCPs with apatite. The composites of calcium phosphate cements derived from tetracalcium phosphate mixed with surface-modified DCPA exhibited excellent mechanical properties, injectability, and interlocking forces between particles, and they also featured nondispersive behavior when immersed in a physiological solution.

  1. Enhanced refrigerant capacity in Gd-Al-Co microwires with a biphase nanocrystalline/amorphous structure

    Energy Technology Data Exchange (ETDEWEB)

    Shen, H. X. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Department of Physics, University of South Florida, Tampa, Florida 33620 (United States); Xing, D. W.; Liu, Y. F.; Sun, J. F. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Sánchez Llamazares, J. L. [Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055 Col. Lomas 4a, San Luis Potosí, S.L.P. 78216 (Mexico); Sánchez-Valdés, C. F. [Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, AP 14, Ensenada 22860, Baja California (Mexico); Belliveau, H.; Srikanth, H.; Phan, M. H., E-mail: phanm@usf.edu [Department of Physics, University of South Florida, Tampa, Florida 33620 (United States); Wang, H.; Qin, F. X. [Institute for Composites Science and Innovation (InCSI), College of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

    2016-02-29

    A class of biphase nanocrystalline/amorphous Gd{sub (50+5x)}Al{sub (30−5x)}Co{sub 20} (x = 0, 1, 2) microwires fabricated directly by melt-extraction is reported. High resolution transmission electron microscopy and Fourier function transform based analysis indicate the presence of a volume fraction (∼20%) of ∼10 nm sized nanocrystallities uniformly embedded in an amorphous matrix. The microwires possess excellent magnetocaloric properties, with large values of the isothermal entropy change (−ΔS{sub M} ∼ 9.7 J kg{sup −1} K{sup −1}), the adiabatic temperature change (ΔT{sub ad} ∼ 5.2 K), and the refrigerant capacity (RC ∼ 654 J kg{sup −1}) for a field change of 5 T. The addition of Gd significantly alters T{sub C} while preserving large values of the ΔS{sub M} and RC. The nanocrystallites allow for enhanced RC as well as a broader operating temperature span of a magnetic bed for energy-efficient magnetic refrigeration.

  2. Improved extraction of fluoroquinolones with recyclable ionic-liquid-based aqueous biphasic systems.

    Science.gov (United States)

    Almeida, Hugo F D; Freire, Mara G; Marrucho, Isabel M

    2016-05-07

    In the past few years, the improvement of advanced analytical tools allowed to confirm the presence of trace amounts of metabolized and unchanged active pharmaceutical ingredients (APIs) in wastewater treatment plants (WWTPs) as well as in freshwater surfaces. It is known that the continuous contact with APIs, even at very low concentrations (ng L(-1)-μg L(-1)), leads to serious human health problems. In this context, this work shows the feasibility of using ionic-liquid-based aqueous biphasic systems (IL-based ABS) in the extraction of quinolones present in aqueous media. In particular, ABS composed of imidazolium- and phosphonium-based ILs and aluminium-based salts (already used in water treatment plants) were evaluated in one-step extractions of six fluoroquinolones (FQs), namely ciprofloxacin, enrofloxacin, moxifloxacin, norfloxacin, ofloxacin and sarafloxacin, and extraction efficiencies up to 98% were obtained. Despite the large interest devoted to IL-based ABS as extractive systems of outstanding performance, their recyclability/reusability has seldomly been studied. An efficient extraction/cleaning process of the IL-rich phase is here proposed by FQs induced precipitation. The recycling of the IL and its further reuse without losses in the ABS extractive performance for FQs were established, as confirmed by the four consecutive removal/extraction cycles evaluated. This novel recycling strategy supports IL-based ABS as sustainable and cost-efficient extraction platforms.

  3. Remedy for fictive negative pressures in biphasic finite element models of the intervertebral disc during unloading.

    Science.gov (United States)

    Schmidt, Hendrik; Galbusera, Fabio; Wilke, Hans-Joachim; Shirazi-Adl, Aboulfazl

    2011-03-01

    Previous biphasic finite element studies investigated the temporal response of a spinal segment under rather simplified loading conditions with no attention to unloading and recovery phases. Employment of existing constitutive relations in porous media yields rather large suction-type pore pressures in the disc as the load suddenly disappears. Such negative pressures are absent in vivo and are hence fictive. The aim of this study was to search for remedies to avoid the computation of negative pressures upon unloading. Partial saturation for the disc or a rest load (RL) higher than 400 N totally eliminated the negative pressures. Decreasing the voids ratio (VR) also led to a reduced negative pressure. When defining a partial saturated disc or using a lower VR in combination with a boundary pressure of 0.25 MPa and a RL of 350 N, no negative pressure was calculated. It appears that the constraint of full saturation and a high mobile fluid fraction of the disc tissues along with inadequate tissue properties are the likely causes of negative pressures during unloading.

  4. Biphasic effect of falcarinol on caco-2 cell proliferation, DNA damage, and apoptosis.

    Science.gov (United States)

    Young, Jette F; Duthie, Susan J; Milne, Lesley; Christensen, Lars P; Duthie, Garry G; Bestwick, Charles S

    2007-02-07

    The polyacetylene falcarinol, isolated from carrots, has been shown to be protective against chemically induced colon cancer development in rats, but the mechanisms are not fully understood. In this study CaCo-2 cells were exposed to falcarinol (0.5-100 microM) and the effects on proliferation, DNA damage, and apoptosis investigated. Low-dose falcarinol exposure (0.5-10 microM) decreased expression of the apoptosis indicator caspase-3 concomitantly with decreased basal DNA strand breakage. Cell proliferation was increased (1-10 microM), whereas cellular attachment was unaffected by falcarinol. At concentrations above 20 microM falcarinol, proliferation of CaCo-2 cells decreased and the number of cells expressing active caspase-3 increased simultaneously with increased cell detachment. Furthermore, DNA single-strand breakage was significantly increased at concentrations above 10 microM falcarinol. Thus, the effects of falcarinol on CaCo-2 cells appear to be biphasic, inducing pro-proliferative and apoptotic characteristics at low and high concentrations of falcarinol, respectively.

  5. The polyacetylenes falcarinol and falcarindiol affect stress responses in myotube cultures in a biphasic manner.

    Science.gov (United States)

    Young, Jette F; Christensen, Lars P; Theil, Peter K; Oksbjerg, Niels

    2008-01-01

    The effects of the bioactive polyacetylenes, falcarinol and falcarindiol, present in carrots, celery, celeriac and other umbelliferous vegetables, on the stress responses in primary myotube cultures, were studied. Biphasic responses on cellular stress responses in myotube cultures were investigated by exposing them to various concentrations of falcarinol and falcarindiol for 24 h before testing effects of 100 microM H(2)O(2) on the intracellular formation of reactive oxygen species (ROS), transcription of the antioxidative enzyme cytosolic glutathione peroxidase (cGPx), and the heat shock proteins (HSP) HSP70 and HO1. At low concentrations (1.6 to 25 microM) polyacetylenes caused a slightly accelerated intra-cellular ROS formation, increased cGPx transcription and decreased HSP70 and HO1 transcription. The increased cGPx transcription may be interpreted as an adaptive response to the increased ROS formation and may have caused a reduced demand for the protective functions of the HSPs. ROS formation, however, was substantially decreased after pre-incubation with both polyacetylenes at 50 and 100 microM, the cGPx transcription was reduced and the HSP70 and HO1 transcription increased, indicating a need for the protective and repairing functions of the HSPs. In conclusion, pre-incubation with low concentrations of both polyacetylenes prior to H(2)O(2) exposure induced a cytoprotective effect whereas higher concentrations had adverse effects.

  6. Antibacterial activity evaluation of bioactive glass and biphasic calcium phosphate nanopowders mixtures

    Science.gov (United States)

    Nazemi, Zahra; Mehdikhani-Nahrkhalaji, Mehdi; Haghbin-Nazarpak, Masoumeh; Staji, Hamid; Kalani, Mohammad Mehdi

    2016-12-01

    The aim of this work was to evaluate the antibacterial activity of bioactive glass (BG) and biphasic calcium phosphate (BCP) nanopowders mixtures for the first time. 37S BG and BCP (50% HA-50% β-TCP) nanopowders were prepared via sol-gel technique. Characterization techniques such as X-ray diffraction, scanning electron microscopy, transition electron microscopy, and X-ray fluorescent. The antibacterial activity was studied using Escherichia coli and Salmonella typhi as gram-negative, and Staphylococcus aureus as gram-positive bacteria. The antibacterial effect of BG, BCP nanopowders, and their mixtures was evaluated at different concentrations. The 37S BG nanopowders showed minimum bactericidal concentration at 25 mg/ml. At broth concentrations below 300 mg/ml, BCP showed no antibacterial activity. BCP and BG nanopowders mixture (M2) with 60/40 ratio of BCP/BG showed noticeable antibacterial effect. It was concluded that BCP and 37S BG nanopowders mixture could be used as a good candidate for dental and orthopedic applications.

  7. Kinetic modelling and microbial community assessment of anaerobic biphasic fixed film bioreactor treating distillery spent wash.

    Science.gov (United States)

    Acharya, Bhavik K; Pathak, Hilor; Mohana, Sarayu; Shouche, Yogesh; Singh, Vasdev; Madamwar, Datta

    2011-08-01

    Anaerobic digestion, microbial community structure and kinetics were studied in a biphasic continuously fed, upflow anaerobic fixed film reactor treating high strength distillery wastewater. Treatment efficiency of the bioreactor was investigated at different hydraulic retention times (HRT) and organic loading rates (OLR 5-20 kg COD m⁻³ d⁻¹). Applying the modified Stover-Kincannon model to the reactor, the maximum removal rate constant (U(max)) and saturation value constant (K(B)) were found to be 2 kg m⁻³ d⁻¹ and 1.69 kg m⁻³ d⁻¹ respectively. Bacterial community structures of acidogenic and methanogenic reactors were assessed using culture-independent analyses. Sequencing of 16S rRNA genes exhibited a total of 123 distinct operational taxonomic units (OTUs) comprising 49 from acidogenic reactor and 74 (28 of eubacteria and 46 of archaea) from methanogenic reactor. The findings reveal the role of Lactobacillus sp. (Firmicutes) as dominant acid producing organisms in acidogenic reactor and Methanoculleus sp. (Euryarchaeotes) as foremost methanogens in methanogenic reactor.

  8. Study on biphasic material model and mechanical analysis of knee joint cartilage

    Science.gov (United States)

    Nakatani, A.; Sakashita, A.

    2008-02-01

    A material model of articular cartilage is formulated, and fundamental problems are analyzed. The soft tissue is assumed to comprise two phases: solid and fluid. The biphasic theory proposed by Spilker and Suh (1990) to deal with such materials is reviewed, and some new additional analyses are carried out on the basis of this theory. Assuming the elasticity for the solid phase and introducing the pressure, which is defined by the product of the volume change and penalty coefficient, it is shown that the viscoelastic property of the soft tissue can be reproduced. A preferable solution is obtained for the solid phase by using the reduction integral, even if a high-order interpolation function is used. However, the high-order element cannot satisfactorily capture the velocity distribution of fluids. The pressure distribution is studied by assuming the change in the surface characteristics of the cartilage tissue with the progress of osteoarthritis. The pressure is strongly related to the lubrication conditions, i.e., perfect lubrication, perfect adhesion, and partial adhesion.

  9. Disrupted glutamate-glutamine cycle in acute encephalopathy with biphasic seizures and late reduced diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Takanashi, Jun-ichi; Terai, Masaru [Tokyo Women' s Medical University Yachiyo Medical Center, Department of Pediatrics, Yachiyo-shi (Japan); Mizuguchi, Masashi [The University of Tokyo, Department of Developmental Medical Sciences, Graduate School of Medicine, Tokyo (Japan); Barkovich, A.J. [University of California San Francisco, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States)

    2015-11-15

    Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is the most common subtype of infectious pediatric encephalopathy in Japan. It is sometimes difficult to make an early diagnosis of AESD; excitotoxicity is postulated to be the pathogenesis based on elevated glutamine (Gln) and glutamate (Glu) complex (Glx = Glu + Gln) observed on MR spectroscopy. It is uncertain whether Gln or Glu contributes to the elevated Glx, or whether MR spectroscopy is useful for an early diagnosis. Five Japanese patients with AESD (three boys and two girls, 1 year of age) were enrolled in this study. MR spectroscopy was acquired from the frontal white matter (repetition time (TR) of 5000 ms, echo time (TE) of 30 ms) with a 1.5- or 3.0-T scanner. MR spectroscopy was performed four times for two patients, three times for one patient, and two times for two patients. Quantification of Glu and Gln was performed using LCModel. Glu was elevated in three of four studies on days 1-4 and became normal or low afterward. Gln was normal in three studies on days 1-2, elevated in all seven studies on days 4-12, and became normal or low afterward. These findings suggest that MR spectroscopy may be useful for an early diagnosis. Acute Glu elevation changes to subacute Gln elevation, suggesting that a disrupted Glu-Gln cycle may play an important role. (orig.)

  10. A biphasic epigenetic switch controls immunoevasion, virulence and niche adaptation in non-typeable Haemophilus influenzae

    Science.gov (United States)

    Atack, John M.; Srikhanta, Yogitha N.; Fox, Kate L.; Jurcisek, Joseph A.; Brockman, Kenneth L.; Clark, Tyson A.; Boitano, Matthew; Power, Peter M.; Jen, Freda E.-C.; McEwan, Alastair G.; Grimmond, Sean M.; Smith, Arnold L.; Barenkamp, Stephen J.; Korlach, Jonas; Bakaletz, Lauren O.; Jennings, Michael P.

    2015-01-01

    Non-typeable Haemophilus influenzae contains an N6-adenine DNA-methyltransferase (ModA) that is subject to phase-variable expression (random ON/OFF switching). Five modA alleles, modA2, modA4, modA5, modA9 and modA10, account for over two-thirds of clinical otitis media isolates surveyed. Here, we use single molecule, real-time (SMRT) methylome analysis to identify the DNA-recognition motifs for all five of these modA alleles. Phase variation of these alleles regulates multiple proteins including vaccine candidates, and key virulence phenotypes such as antibiotic resistance (modA2, modA5, modA10), biofilm formation (modA2) and immunoevasion (modA4). Analyses of a modA2 strain in the chinchilla model of otitis media show a clear selection for ON switching of modA2 in the middle ear. Our results indicate that a biphasic epigenetic switch can control bacterial virulence, immunoevasion and niche adaptation in an animal model system. PMID:26215614

  11. A biphasic epigenetic switch controls immunoevasion, virulence and niche adaptation in non-typeable Haemophilus influenzae.

    Science.gov (United States)

    Atack, John M; Srikhanta, Yogitha N; Fox, Kate L; Jurcisek, Joseph A; Brockman, Kenneth L; Clark, Tyson A; Boitano, Matthew; Power, Peter M; Jen, Freda E-C; McEwan, Alastair G; Grimmond, Sean M; Smith, Arnold L; Barenkamp, Stephen J; Korlach, Jonas; Bakaletz, Lauren O; Jennings, Michael P

    2015-07-28

    Non-typeable Haemophilus influenzae contains an N(6)-adenine DNA-methyltransferase (ModA) that is subject to phase-variable expression (random ON/OFF switching). Five modA alleles, modA2, modA4, modA5, modA9 and modA10, account for over two-thirds of clinical otitis media isolates surveyed. Here, we use single molecule, real-time (SMRT) methylome analysis to identify the DNA-recognition motifs for all five of these modA alleles. Phase variation of these alleles regulates multiple proteins including vaccine candidates, and key virulence phenotypes such as antibiotic resistance (modA2, modA5, modA10), biofilm formation (modA2) and immunoevasion (modA4). Analyses of a modA2 strain in the chinchilla model of otitis media show a clear selection for ON switching of modA2 in the middle ear. Our results indicate that a biphasic epigenetic switch can control bacterial virulence, immunoevasion and niche adaptation in an animal model system.

  12. Biphasic regulation of the transcription factor ABORTED MICROSPORES (AMS) is essential for tapetum and pollen development in Arabidopsis.

    Science.gov (United States)

    Ferguson, Alison C; Pearce, Simon; Band, Leah R; Yang, Caiyun; Ferjentsikova, Ivana; King, John; Yuan, Zheng; Zhang, Dabing; Wilson, Zoe A

    2017-01-01

    Viable pollen is essential for plant reproduction and crop yield. Its production requires coordinated expression at specific stages during anther development, involving early meiosis-associated events and late pollen wall formation. The ABORTED MICROSPORES (AMS) transcription factor is a master regulator of sporopollenin biosynthesis, secretion and pollen wall formation in Arabidopsis. Here we show that it has complex regulation and additional essential roles earlier in pollen formation. An inducible-AMS reporter was created for functional rescue, protein expression pattern analysis, and to distinguish between direct and indirect targets. Mathematical modelling was used to create regulatory networks based on wild-type RNA and protein expression. Dual activity of AMS was defined by biphasic protein expression in anther tapetal cells, with an initial peak around pollen meiosis and then later during pollen wall development. Direct AMS-regulated targets exhibit temporal regulation, indicating that additional factors are associated with their regulation. We demonstrate that AMS biphasic expression is essential for pollen development, and defines distinct functional activities during early and late pollen development. Mathematical modelling suggests that AMS may competitively form a protein complex with other tapetum-expressed transcription factors, and that biphasic regulation is due to repression of upstream regulators and promotion of AMS protein degradation.

  13. Post-stimulation block of frog sciatic nerve by high-frequency (kHz) biphasic stimulation.

    Science.gov (United States)

    Yang, Guangning; Xiao, Zhiying; Wang, Jicheng; Shen, Bing; Roppolo, James R; de Groat, William C; Tai, Changfeng

    2017-04-01

    This study determined if high-frequency biphasic stimulation can induce nerve conduction block that persists after the stimulation is terminated, i.e., post-stimulation block. The frog sciatic nerve-muscle preparation was used in the study. Muscle contraction force induced by low-frequency (0.5 Hz) nerve stimulation was recorded to indicate the occurrence and recovery of nerve block induced by the high-frequency (5 or 10 kHz) biphasic stimulation. Nerve block was observed during high-frequency stimulation and after termination of the stimulation. The recovery from post-stimulation block occurred in two distinct phases. During the first phase, the complete block induced during high-frequency stimulation was maintained. The average maximal duration for the first phase was 107 ± 50 s. During the second phase, the block gradually or abruptly reversed. The duration of both first and second phases was dependent on stimulation intensity and duration but not frequency. Stimulation of higher intensity (1.4-2 times block threshold) and longer duration (5 min) produced the longest period (249 ± 58 s) for a complete recovery. Post-stimulation block can be induced by high-frequency biphasic stimulation, which is important for future investigations of the blocking mechanisms and for optimizing the stimulation parameters or protocols in clinical applications.

  14. Biphasic role of chondroitin sulfate in cardiac differentiation of embryonic stem cells through inhibition of Wnt/β-catenin signaling.

    Directory of Open Access Journals (Sweden)

    Robert D Prinz

    Full Text Available The glycosaminoglycan chondroitin sulfate is a critical component of proteoglycans on the cell surface and in the extracellular matrix. As such, chondroitin sulfate side chains and the sulfation balance of chondroitin play important roles in the control of signaling pathways, and have a functional importance in human disease. In contrast, very little is known about the roles of chondroitin sulfate molecules and sulfation patterns during mammalian development and cell lineage specification. Here, we report a novel biphasic role of chondroitin sulfate in the specification of the cardiac cell lineage during embryonic stem cell differentiation through modulation of Wnt/beta-catenin signaling. Lineage marker analysis demonstrates that enzymatic elimination of endogenous chondroitin sulfates leads to defects specifically in cardiac differentiation. This is accompanied by a reduction in the number of beating cardiac foci. Mechanistically, we show that endogenous chondroitin sulfate controls cardiac differentiation in a temporal biphasic manner through inhibition of the Wnt/beta-catenin pathway, a known regulatory pathway for the cardiac lineage. Treatment with a specific exogenous chondroitin sulfate, CS-E, could mimic these biphasic effects on cardiac differentiation and Wnt/beta-catenin signaling. These results establish chondroitin sulfate and its sulfation balance as important regulators of cardiac cell lineage decisions through control of the Wnt/beta-catenin pathway. Our work suggests that targeting the chondroitin biosynthesis and sulfation machinery is a novel promising avenue in regenerative strategies after heart injury.

  15. <