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Sample records for vascular graft materials

  1. Five types of polyurethane vascular grafts in dogs: the importance of structural design and material selection.

    Science.gov (United States)

    Xie, Xingyi; Eberhart, Andreas; Guidoin, Robert; Marois, Yves; Douville, Yvan; Zhang, Ze

    2010-01-01

    Five polyurethane vascular grafts with three different chemistries were investigated in terms of device function, healing characteristics and material stability in a canine abdominal aorta model for prescheduled periods of 1 and 6 months. Corvita-reinforced grafts, with walls made of poly(carbonate urethane) (PCU) filaments, displayed a relatively thin, uniform and partially endothelialized inner capsule with good tissue in-growth. The external polyester mesh separated from the underlying PCU wall due to the degradation of the melt adhesive between these two layers. Three types of Thoratec access graft exhibited a high degree of thrombus and little tissue in-growth, and were non-adhesive to both the inner and external capsules as the solid layer beneath their lumens completely blocked any transmural communication. The microporous poly(ether urethane urea) degraded extensively. Pulse-Tec grafts at one month also demonstrated non-adhesive properties because the external skin served as a barrier to tissue in-growth. At 6 months, its poly(ether urethane) wall displayed the most severe degradation, damaging graft structural integrity and causing significant tissue deposition in the degradation areas. This study shows the importance of multiple factors in vascular prosthesis design and demonstrates that collective and comprehensive thinking will be key in the future development of creative and novel approaches.

  2. Polydopamine-mediated immobilization of multiple bioactive molecules for the development of functional vascular graft materials.

    Science.gov (United States)

    Lee, Yu Bin; Shin, Young Min; Lee, Ji-Hye; Jun, Indong; Kang, Jae Kyeong; Park, Jong-Chul; Shin, Heungsoo

    2012-11-01

    In this study, we introduced a simple method for polydopamine-mediated immobilization of dual bioactive factors for the preparation of functionalized vascular graft materials. Polydopamine was deposited on elastic and biodegradable poly(lactic acid-co-ɛ-caprolactone) (PLCL) films, and a cell adhesive RGD-containing peptide and basic fibroblast growth factor were subsequently immobilized by simple dipping. We used an enzyme-linked immunosorbent assay and fluorescamine assay to confirm that we had stably immobilized bioactive molecules on the polydopamine-coated PLCL film in a reaction time-dependent manner. When human umbilical vein endothelial cells (HUVEC) were cultured on the prepared substrates, the number of adherent cells and proliferation of HUVEC for up to 14 days were greatest on the film immobilized with dual factors. On the other hand, the film immobilized with RGD peptide exhibited the highest migration speed compared to the other groups. The expression of cluster of differentiation 31 and von Willebrand factor, which indicates maturation of endothelial cells, was highly stimulated in the dual factor-immobilized group, and passively adsorbed factors showed a negligible effect. The immobilization of bioactive molecules inspired by polydopamine was successful, and adhesion, migration, proliferation and differentiation of HUVEC were synergistically accelerated by the presence of multiple signaling factors. Collectively, our results have demonstrated that a simple coating with polydopamine enables the immobilization of multiple bioactive molecules for preparation of polymeric functionalized vascular graft materials. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Vascularized fibular graft in infected tibial bone loss

    OpenAIRE

    C Cheriyan Kovoor; R Jayakumar; V V George; Vinod Padmanabhan; A J Guild; Sabin Viswanath

    2011-01-01

    Background : The treatment options of bone loss with infections include bone transport with external fixators, vascularized bone grafts, non-vascularized autogenous grafts and vascularized allografts. The research hypothesis was that the graft length and intact ipsilateral fibula influenced hypertrophy and stress fracture. We retrospectively studied the graft hypertrophy in 15 patients, in whom vascularized fibular graft was done for post-traumatic tibial defects with infection. Materials...

  4. Design and development of multilayer vascular graft

    Science.gov (United States)

    Madhavan, Krishna

    2011-07-01

    Vascular graft is a widely-used medical device for the treatment of vascular diseases such as atherosclerosis and aneurysm as well as for the use of vascular access and pediatric shunt, which are major causes of mortality and morbidity in this world. Dysfunction of vascular grafts often occurs, particularly for grafts with diameter less than 6mm, and is associated with the design of graft materials. Mechanical strength, compliance, permeability, endothelialization and availability are issues of most concern for vascular graft materials. To address these issues, we have designed a biodegradable, compliant graft made of hybrid multilayer by combining an intimal equivalent, electrospun heparin-impregnated poly-epsilon-caprolactone nanofibers, with a medial equivalent, a crosslinked collagen-chitosan-based gel scaffold. The intimal equivalent is designed to build mechanical strength and stability suitable for in vivo grafting and to prevent thrombosis. The medial equivalent is designed to serve as a scaffold for the activity of the smooth muscle cells important for vascular healing and regeneration. Our results have shown that genipin is a biocompatible crosslinker to enhance the mechanical properties of collagen-chitosan based scaffolds, and the degradation time and the activity of smooth muscle cells in the scaffold can be modulated by the crosslinking degree. For vascular grafting and regeneration in vivo, an important design parameter of the hybrid multilayer is the interface adhesion between the intimal and medial equivalents. With diametrically opposite affinities to water, delamination of the two layers occurs. Physical or chemical modification techniques were thus used to enhance the adhesion. Microscopic examination and graft-relevant functional characterizations have been performed to evaluate these techniques. Results from characterization of microstructure and functional properties, including burst strength, compliance, water permeability and suture

  5. Development of a Composite Electrospun Polyethylene Terephthalate-Polyglycolic Acid Material: Potential Use as a Drug-Eluting Vascular Graft

    Directory of Open Access Journals (Sweden)

    Christoph S. Nabzdyk

    2015-01-01

    Full Text Available Intimal hyperplasia (IH, an excessive wound healing response of an injured vessel wall after bypass grafting, typically leads to prosthetic bypass graft failure. In an approach to ameliorate IH, nondegradable poly(ethylene terephthalate or PET, which has been used in prosthetic vascular grafts for over 60 years, and biodegradable poly(glycolic acid or PGA were electrospun using different techniques to generate a material that may serve as permanent scaffold and as a drug/biologic delivery device. PET and PGA polymers were electrospun from either a single-blended solution (ePET/ePGA-s or two separate polymer solutions (ePET/ePGA-d. ePET/ePGA-d material revealed two distinct fibers and was significantly stronger than the single fiber ePET/ePGA-s material. After 21 days of incubation in PBS, ePET-PGA-s showed fiber strand breaks likely due to the degradation of the PGA within the ePET-ePGA-s fiber, while the ePET/ePGA-d material showed intact ePET fibers even after ePGA fiber degradation. The ePET/ePGA- material was able to release red fluorescent dye for at least 14 days. Attachment of human aortic smooth muscle cells (AoSMCs was similar to both materials. ePET/ePGA-d materials maybe a step towards bypass graft materials that can be custom-designed to promote cellular attachment while serving as a drug delivery platform for IH prevention.

  6. Additive Manufacturing of Vascular Grafts and Vascularized Tissue Constructs.

    Science.gov (United States)

    Elomaa, Laura; Yang, Yunzhi Peter

    2017-10-01

    There is a great need for engineered vascular grafts among patients with cardiovascular diseases who are in need of bypass therapy and lack autologous healthy blood vessels. In addition, because of the severe worldwide shortage of organ donors, there is an increasing need for engineered vascularized tissue constructs as an alternative to organ transplants. Additive manufacturing (AM) offers great advantages and flexibility of fabrication of cell-laden, multimaterial, and anatomically shaped vascular grafts and vascularized tissue constructs. Various inkjet-, extrusion-, and photocrosslinking-based AM techniques have been applied to the fabrication of both self-standing vascular grafts and porous, vascularized tissue constructs. This review discusses the state-of-the-art research on the use of AM for vascular applications and the key criteria for biomaterials in the AM of both acellular and cellular constructs. We envision that new smart printing materials that can adapt to their environment and encourage rapid endothelialization and remodeling will be the key factor in the future for the successful AM of personalized and dynamic vascular tissue applications.

  7. USPIO-labeled textile materials for non-invasive MR imaging of tissue-engineered vascular grafts

    NARCIS (Netherlands)

    Mertens, Marianne E.; Koch, Sabine; Lammers, Twan Gerardus Gertudis Maria; Schuster, Philipp; Wehner, Jakob; Wu, Zhuojun; Gremse, Felix; Schulz, Volkmar; Rongen, Lisanne; Wolf, Frederic; Frese, Julia; Gesche, Valentine N.; van Zandvoort, Marc; Mela, P.; Jockenhoeve, Stefan; Kiessling, Fabian

    2015-01-01

    Non-invasive imaging might assist in the clinical translation of tissue-engineered vascular grafts (TEVG). It can e.g. be used to facilitate the implantation of TEVG, to longitudinally monitor their localization and function, and to provide non-invasive and quantitative feedback on their remodeling

  8. Effects Of Gelatine-Coated Vascular Grafts On Human Neutrophils.

    Science.gov (United States)

    Meyer, Frank; Buerger, Thomas; Halloul, Zuhir; Lippert, Hans; König, Brigitte; Tautenhahn, Joerg

    2015-09-01

    The aim of the study was to investigate the immune-modulatory potential of commercially available PTFE and polyester vascular grafts with and without gelatine-coating. The biomaterial-cell-interaction was characterized by changes of established parameters such as PMN-related receptors/mediators, phagocytosis potential and capacity as well as the effect of an additional plasma-dependent modulation. By means of a standardized experimental in vitro model, various vascular graft material (PTFE/polyester/uncoated/gelatine-coated) was used for incubation with or without plasma and co-culturing with human neutrophile granulocytes (PMN) followed by analysis of representative receptors and mediators (CD62L, CD11b, CXCR2, fMLP-R, IL-8, Elastase, LTB4). Oxidative burst assessed phagocytosis capacity. Comparing the vascular grafts, un-coated PTFE induced the lowest magnitude of cell stimulation whereas in case of gelatine-coating, cell response exceeded those of the other vascular grafts. This was also found comparing the polyester-based prosthetic material. Gelatine-coated polyester led to a more pronounced release of elastase than gelatine-coated PTFE and the uncoated materials. The results of oxidative burst indicated a reduced phagocytosis capacity in case of gelatine-coated polyester. Plasma incubation did also provide an impact on the cellular response. While in case of gelatine-coating, PMN-related receptor stimulation became lower, it increased by native polyester. The latter one did also induce more mediators such as IL-8 and LTB4 than gelatine-coated material. There have been no extensive data on cell-cell interactions, cytokines and general histo-/hemocompatibility of human cells by the new generation of vascular grafts. It remains still open whether healing process and infectious resistance can be compromised by material-dependent over-stimulation or reduced phagocytosis potential of the immune cells of the primary unspecific immune response induced by gelatine

  9. Vascularized fibular graft in infected tibial bone loss

    Directory of Open Access Journals (Sweden)

    C Cheriyan Kovoor

    2011-01-01

    Full Text Available Background : The treatment options of bone loss with infections include bone transport with external fixators, vascularized bone grafts, non-vascularized autogenous grafts and vascularized allografts. The research hypothesis was that the graft length and intact ipsilateral fibula influenced hypertrophy and stress fracture. We retrospectively studied the graft hypertrophy in 15 patients, in whom vascularized fibular graft was done for post-traumatic tibial defects with infection. Materials and Methods : 15 male patients with mean age 33.7 years (range 18 - 56 years of post traumatic tibial bone loss were analysed. The mean bony defect was 14.5 cm (range 6.5 - 20 cm. The mean length of the graft was 16.7 cm (range 11.5 - 21 cm. The osteoseptocutaneous flap (bone flap with attached overlying skin flap from the contralateral side was used in all patients except one. The graft was fixed to the recipient bone at both ends by one or two AO cortical screws, supplemented by a monolateral external fixator. A standard postoperative protocol was followed in all patients. The hypertrophy percentage of the vascularized fibular graft was calculated by a modification of the formula described by El-Gammal. The followup period averaged 46.5 months (range 24 - 164 months. The Pearson correlation coefficient (r was worked out, to find the relationship between graft length and hypertrophy. The t-test was performed to find out if there was any significant difference in the graft length of those who had a stress fracture and those who did not and to find out whether there was any significant difference in hypertrophy with and without ipsilateral fibula union. The Chi square test was performed to identify whether there was any association between the stress fracture and the fibula union. Given the small sample size we have not used any statistical analysis to determine the relation between the percentage of the graft hypertrophy and stress fracture. Results : Graft

  10. Prevention of primary vascular graft infection with silver-coated polyester graft in a porcine model

    DEFF Research Database (Denmark)

    Gao, H; Sandermann, J; Prag, J

    2010-01-01

    To evaluate the efficacy of a silver-coated vascular polyester graft in the prevention of graft infection after inoculation with Staphylococcus aureus in a porcine model.......To evaluate the efficacy of a silver-coated vascular polyester graft in the prevention of graft infection after inoculation with Staphylococcus aureus in a porcine model....

  11. Heparin-bonded expanded polytetrafluoroethylene vascular graft for femoropopliteal and femorocrural bypass grafting: 1-year results.

    Science.gov (United States)

    Bosiers, Marc; Deloose, Koen; Verbist, Jürgen; Schroë, Herman; Lauwers, Geert; Lansink, Wouter; Peeters, Patrick

    2006-02-01

    Several prosthetic materials have been used for femoropopliteal bypass grafting in patients with peripheral vascular disease in whom a venous bypass is not possible. Expanded polytetrafluoroethylene (ePTFE) is the most commonly used, but patency results have not always equaled those achieved with vein, especially in below-knee reconstructions. This study assessed the performance of a new heparin-bonded ePTFE vascular graft that was designed to provide resistance to thrombosis and thereby decrease early graft failures and possibly prolong patency. From June 2002 to June 2003, 86 patients (62 men and 24 women; mean age, 70 years; 99 diseased limbs) were enrolled prospectively in a nonrandomized, multicenter study of the heparin-bonded ePTFE graft. Fifty-five above-knee and 44 below-knee (including 21 femorocrural) procedures were performed. Follow-up evaluations consisted of clinical examinations, ultrasonographic studies, and distal pulse assessments. Patency and limb salvage rates were assessed by using life-table analyses. All grafts were patent immediately after implantation. There were no graft infections or episodes of prolonged anastomotic bleeding. During the 1-year follow-up, 10 patients died, 15 grafts occluded, and 5 major amputations were performed. The overall primary and secondary 1-year patency rates were 82% and 97%, respectively. The limb salvage rate in patients with critical limb ischemia (n = 41) was 87%. Primary patency rates according to bypass type were 84%, 81%, and 74% for above-knee femoropopliteal, below-knee femoropopliteal, and femorocrural bypasses, respectively; the corresponding secondary patency rates were 96%, 100%, and 100%. In this study, the heparin-bonded ePTFE graft provided promising early patency and limb salvage results, with no device-related complications, in patients with occlusive vascular disease. Longer-term and randomized studies are warranted to determine whether this graft provides results superior to those achieved

  12. Tropoelastin inhibits intimal hyperplasia of mouse bioresorbable arterial vascular grafts.

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    Sugiura, Tadahisa; Agarwal, Riddhima; Tara, Shuhei; Yi, Tai; Lee, Yong-Ung; Breuer, Christopher K; Weiss, Anthony S; Shinoka, Toshiharu

    2017-04-01

    Neointimal hyperplasia, which results from the activation, proliferation and migration of vascular smooth muscle cells (SMCs), is a detrimental condition for vascular stents or vascular grafts that leads to stenosis. Preventing neointimal hyperplasia of vascular grafts is critically important for the success of arterial vascular grafts. We hypothesized that tropoelastin seeding onto the luminal surface of the graft would prevent neointimal hyperplasia through suppressing neointimal smooth muscle cell proliferation. In this study, we investigated the efficacy of tropoelastin seeding in preventing neointimal hyperplasia of bioresorbable arterial vascular grafts. Poly (glycolic acid) (PGA) fiber mesh coated with poly (l-lactic-co-ε-caprolactone) (PLCL) scaffolds reinforced by poly (l-lactic acid) (PLA) nano-fibers were prepared as bioresorbable arterial grafts. Tropoelastin was then seeded onto the luminal surface of the grafts. Tropoelastin significantly reduced the thickness of the intimal layer. This effect was mainly due to a substantial reduction the number of cells that stained positive for SMC (α-SMA) and PCNA in the vessel walls. Mature elastin and collagen type I and III were unchanged with tropoelastin treatment. This study demonstrates that tropoelastin seeding is beneficial in preventing SMC proliferation and neointimal hyperplasia in bioresorbable arterial vascular grafts. Small resorbable vascular grafts can block due to the over-proliferation of smooth muscle cells in neointimal hyperplasia. We show here that the proliferation of these cells is restricted in this type of graft. This is achieved with a simple dip, non-covalent coating of tropoelastin. It is in principle amendable to other grafts and is therefore an attractive process. This study is particularly significant because: (1) it shows that smooth muscle cell proliferation can be reduced while still accommodating the growth of endothelial cells, (2) small vascular grafts with an internal

  13. Composite vascular grafts with high cell infiltration by co-electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Zhikai, E-mail: tanzk@hnu.edu.cn; Wang, Hongjie; Gao, Xiangkai; Liu, Tong; Tan, Yongjun

    2016-10-01

    There is an increasing demand for functional small-diameter vascular grafts (diameter < 6 mm) to be used in clinical arterial replacement. An ideal vascular graft should have appropriate biomechanical properties and be biocompatible. Electrospinning has become a popular polymer processing technique for vascular tissue engineering, but the grafts fabricated by electrospinning often have relatively small pores and low porosity, which limit cell infiltration into scaffolds and hinder the regeneration and remodeling of grafts. In the present study, we aimed to develop an efficient method to prepare electrospun composite vascular grafts comprising natural and synthetic materials. We fabricated grafts made of polycaprolactone, gelatin, and polyvinyl alcohol (PVA) by co-electrospinning, and the scaffolds were further functionalized by immobilizing heparin on them. The PVA fibers degraded rapidly in vivo and generated electrospun scaffolds with high porosity, which significantly enhanced cell proliferation and infiltration. The mechanical properties of the grafts are suitable for use in artery replacement. Heparin functionalization of the grafts yielded a good antithrombogenic effect, which was demonstrated in platelet adhesion tests. Moreover, in vitro and in vivo results demonstrated that the heparin release from the grafts enhanced the growth of endothelial cells, which is important for the endothelium of implanted grafts. The results of this study indicate that our method is effective and controllable for the fabrication of vascular grafts that meet the clinical requirements for blood vessel transplantation. - Highlights: • This study indicate an effective method for the fabrication of vascular grafts that meet the clinical requirements. • Co-electrospinning were used to fabricate grafts made of polycaprolactone (PCL), gelatin (GT), and polyvinyl alcohol (PVA). • PVA was used to create large pores within the hybrid scaffolds, thereby enhancing cell infiltration

  14. Experimental autologous substitute vascular graft for transplantation surgery

    NARCIS (Netherlands)

    Kobori, L; Dallos, G; Gouw, ASH; Nemeth, T; Nemes, B; Fehervari, I; Tegzess, Adam; Slooff, MJH; Perner, F; De Jong, KP

    2000-01-01

    Vascular complications in fiver transplantation are a major cause of graft failure and mortality. The aim of the study was to create autologous vascular graft without risk of rejection. Posterior rectus fascia sheath lined with peritoneum was used for iliac artery replacement in seven mongrel dogs.

  15. [Surgical management of limb prosthetic vascular graft exposure].

    Science.gov (United States)

    Wu, Hao; Wu, Wei-wei; Bai, Ming; Zeng, Rong; Song, Xiao-jun; Chen, Yu; Liu, Chang-wei

    2012-12-01

    To investigate the risk factors and surgical management of limb prosthetic vascular graft exposure. The clinical data of 17 patients suffering from limb prosthetic vascular graft exposure in Peking Union Medical College Hospital from August 2006 to December 2011 were retrospectively analyzed. Among 17 cases, 5 suffered from prosthetic vascular graft exposure after vascular bypass for the lower limb ischemia, whereas 12 were affected after the artificial graft arteriovenous fistula construction in the upper limbs for hemodialysis. The surgical procedures mainly included the local debridement as well as the local flap and transferred muscle-cutaneous flap reconstruction to preserve the prosthetic vascular graft. All 17 patients underwent local flap or muscle-cutaneous flap coverage procedure. After the surgery, the prosthetic vascular graft was successfully salvaged in 14 cases. The total successful rate was 82.4%. The surgery failed in three patients, in whom the prosthetic vascular grafts were finally removed. Local flap and transferred muscle-cutaneous flap reconstruction is an effective surgical management to salvage the exposed grafts.

  16. The effect of autoclave resterilisation on polyester vascular grafts.

    Science.gov (United States)

    Riepe, G; Whiteley, M S; Wente, A; Rogge, A; Schröder, A; Galland, R B; Imig, H

    1999-11-01

    polyester grafts are expensive, single-use items. Some manufacturers of uncoated, woven grafts include instructions for autoclave resterilisation to be performed at the surgeon's own request. Others warn against such manipulation. Theoretically, the glass transition point of polyester at 70-80 degrees C and the possible acceleration of hydrolysis suggest that autoclave resterilisation at 135 degrees C might be a problem. a DeBakey Soft Woven Dacron Vascular Prosthesis (Bard) and a Woven Double Velour Dacron Graft (Meadox) were autoclave-resterilised 0 to 20 times, having been weighed before and after sterilisation. Tactile testing was performed. Mechanical properties were examined by probe puncture and single-filament testing, the surface was examined by scanning electron microscopy and the degree of hydrolysis by infra-red spectroscopy. tactile testing revealed a change of feeling with increasing cycles of resterilisation. Investigation of weight, textile strength, single-filament strength, electron microscopy of the surface and infra-red spectroscopy showed no change of the material. changes felt are presumably a surface phenomenon, not measurably affecting strength or chemistry of material after autoclave resterilisation. We therefore feel that it is safe to use once-autoclave-resterilised surplus uncoated polyester grafts, provided that sterility is guaranteed. Copyright 1999 Harcourt Publishers Ltd.

  17. Mussel-inspired immobilization of vascular endothelial growth factor (VEGF) for enhanced endothelialization of vascular grafts.

    Science.gov (United States)

    Shin, Young Min; Lee, Yu Bin; Kim, Seok Joo; Kang, Jae Kyeong; Park, Jong-Chul; Jang, Wonhee; Shin, Heungsoo

    2012-07-09

    Most polymeric vascular prosthetic materials have low patency rate for replacement of small diameter vessels (polydopamine-mediated immobilization of growth factors on the surface of polymeric materials as a versatile tool to modify surface characteristics of vascular grafts potentially for accelerated endothelialization. Polydopamine was deposited on the surface of biocompatible poly(L-lactide-co-ε-caprolactone) (PLCL) elastomer, on which vascular endothelial growth factor (VEGF) was subsequently immobilized by simple dipping. Surface characteristics and composition were investigated by using scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. Immobilization of VEGF on the polydopamine-deposited PLCL films was effective (19.8 ± 0.4 and 197.4 ± 19.7 ng/cm(2) for DPv20 and DPv200 films, respectively), and biotin-mediated labeling of immobilized VEGF revealed that the fluorescence intensity increased as a function of the concentration of VEGF solution. The effect of VEGF on adhesion of HUVECs was marginal, which may have been masked by polydopamine layer that also enhanced cell adhesion. However, VEGF-immobilized substrate significantly enhanced proliferation of HUVECs for over 7 days of in vitro culture and also improved their migration. In addition, immobilized VEGF supported robust cell to cell interactions with strong expression of CD 31 marker. The same process was effective for immobilization of basic fibroblast growth factor, demonstrating the robustness of polydopamine layer for secondary ligation of growth factors as a simple and novel surface modification strategy for vascular graft materials.

  18. Dynamic, nondestructive imaging of a bioengineered vascular graft endothelium.

    Directory of Open Access Journals (Sweden)

    Bryce M Whited

    Full Text Available Bioengineering of vascular grafts holds great potential to address the shortcomings associated with autologous and conventional synthetic vascular grafts used for small diameter grafting procedures. Lumen endothelialization of bioengineered vascular grafts is essential to provide an antithrombogenic graft surface to ensure long-term patency after implantation. Conventional methods used to assess endothelialization in vitro typically involve periodic harvesting of the graft for histological sectioning and staining of the lumen. Endpoint testing methods such as these are effective but do not provide real-time information of endothelial cells in their intact microenvironment, rather only a single time point measurement of endothelium development. Therefore, nondestructive methods are needed to provide dynamic information of graft endothelialization and endothelium maturation in vitro. To address this need, we have developed a nondestructive fiber optic based (FOB imaging method that is capable of dynamic assessment of graft endothelialization without disturbing the graft housed in a bioreactor. In this study we demonstrate the capability of the FOB imaging method to quantify electrospun vascular graft endothelialization, EC detachment, and apoptosis in a nondestructive manner. The electrospun scaffold fiber diameter of the graft lumen was systematically varied and the FOB imaging system was used to noninvasively quantify the affect of topography on graft endothelialization over a 7-day period. Additionally, results demonstrated that the FOB imaging method had a greater imaging penetration depth than that of two-photon microscopy. This imaging method is a powerful tool to optimize vascular grafts and bioreactor conditions in vitro, and can be further adapted to monitor endothelium maturation and response to fluid flow bioreactor preconditioning.

  19. Vascularized bone graft for oncological reconstruction of the extremities: review of the biological advantages.

    Science.gov (United States)

    Muramatsu, Keiichi; Hashimoto, Takahiro; Tominaga, Yasuhiro; Taguchi, Toshihiko

    2014-06-01

    Vascularized bone graft (VBG) is a form of vascularized bone marrow transplant in which the bone marrow is surgically grafted with its microenvironment intact. Due to the preservation of cellular viability, VBG have significant advantages over non-vascularized bone grafts. Free vascularized fibula grafts have superior material properties and tolerate infection. Bone healing can be accomplished in a shorter period, even in an irradiated bed. In addition to these properties, VBG has other biological advantages that are not always familiar to oncological surgeons. Hypertrophic change can be divided into reactive and adaptive hypertrophy. Early hypertrophy is associated with donor-derived cells, whereas later remodeling is associated with recipient-derived cells. VBG has significant advantages in enhancing neo-revascularization of necrotic bone. We reviewed VBG from a novel viewpoint that stems from our basic research. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  20. Bypass materials in vascular surgery

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    Willich, Stephan N.

    2006-03-01

    Full Text Available Introduction: Arteriosclerotic changes can lead to circulatory disturbances in various areas of the human vascular system. In addition to pharmacological therapy and the management of risk factors (e. g. hypertension, diabetes, lipid metabolism disorders, and lifestyle, surgical interventions also play an important role in the treatment of arteriosclerosis. Long-segment arterial occlusions, in particular, can be treated successfully with bypass sur-gery. A number of different materials are available for this type of operation, such as autologous vein or pros-thetic grafts comprised of polytetrafluoroethylene (PTFE or Dacron®. Prosthetic materials are used especially in the treatment of peripheral artery disease, such as in aortoiliac or femoropopliteal bypass surgery. The present report will thus focus on this area in order to examine the effectiveness of different bypass materials. Among the efforts being made to refine the newly introduced DRG system in Germany, analysing the different bypass materials used in vascular surgery is particularly important. Indeed, in its current version the German DRG system does not distinguish between bypass materials in terms of reimbursement rates. Differences in cost structures are thus of especial interest to hospitals in their budget calculations, whereas both private and statutory health insurance funds are primarily interested in long-term results and their costs. Objectives: The goal of this HTA is to compare the different bypass materials used in vascular surgery in terms of their medical efficiency and cost-effectiveness, as well as with regard to their ethical, social and legal implications. In addition, this report aims to point out the areas in which further medical, epidemiological and health economic research is still needed. Methods: Relevant publications were identified by means of a structured search of databases accessed through the German Institute of Medical Documentation and Information

  1. Preparation and features of polycaprolactone vascular grafts with the incorporated vascular endothelial growth factor

    Energy Technology Data Exchange (ETDEWEB)

    Sevostyanova, V. V., E-mail: sevostyanova.victoria@gmail.com; Khodyrevskaya, Y. I.; Glushkova, T. V.; Antonova, L. V.; Kudryavtseva, Y. A.; Barbarash, O. L.; Barbarash, L. S. [Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo (Russian Federation)

    2015-10-27

    The development of tissue-engineered small-diameter vascular grafts is an urgent issue in cardiovascular surgery. In this study, we assessed how the incorporation of the vascular endothelial growth factor (VEGF) affects morphological and mechanical properties of polycaprolactone (PCL) vascular grafts along with its release kinetics. Vascular grafts were prepared using two-phase electrospinning. In pursuing our aims, we performed scanning electron microscopy, mechanical testing, and enzyme-linked immunosorbent assay. Our results demonstrated the preservation of a highly porous structure and improvement of PCL/VEGF scaffold mechanical properties as compared to PCL grafts. A prolonged VEGF release testifies the use of this construct as a scaffold for tissue-engineered vascular grafts.

  2. Vascularized bone grafts for congenital pseudarthrosis of the tibia.

    Science.gov (United States)

    Kanaya, F; Tsai, T M; Harkess, J

    1996-01-01

    Eight vascularized fibula grafts and two vascularized rib grafts were used for the treatment of 10 Boyd's Type II congenital pseudarthrosis of the tibia. All but one vascularized fibula graft united within 4 months. The two vascularized rib grafts did not unite until receiving a conventional bone graft. Nine spontaneous fractures were seen in four patients; all were subsequently treated successfully with cast or conventional bone graft. Corrective osteotomies were done in two patients. Follow-up averaged 8 years and 5 months (range, 5 years and 1 month to 14 years and 4 months). Average age at end of follow-up was 13 years and 6 months (range, 7 years and 10 months to 20 years and 4 months). After bony union was achieved, shortening of the affected leg averaged 3.8 centimeters, flexion deformity averaged 20 degrees, and valgus deformity averaged 24 degrees. In three patients, whose leg discrepancy averaged 4.9 centimeters, the leg was lengthened at an average patient age of 13 years and 9 months (age range, 11 years and 7 months to 15 years and 2 months). The resulting limb length discrepancy averaged 2.2 centimeters. Vascularized bone grafting is a reliable technique for achieving bony union in congenital pseudarthrosis of the tibia. Residual shortening may be corrected later by limb lengthening.

  3. Engineering the mechanical and biological properties of nanofibrous vascular grafts for in situ vascular tissue engineering.

    Science.gov (United States)

    Henry, Jeffrey J D; Yu, Jian; Wang, Aijun; Lee, Randall; Fang, Jun; Li, Song

    2017-08-17

    Synthetic small diameter vascular grafts have a high failure rate, and endothelialization is critical for preventing thrombosis and graft occlusion. A promising approach is in situ tissue engineering, whereby an acellular scaffold is implanted and provides stimulatory cues to guide the in situ remodeling into a functional blood vessel. An ideal scaffold should have sufficient binding sites for biomolecule immobilization and a mechanical property similar to native tissue. Here we developed a novel method to blend low molecular weight (LMW) elastic polymer during electrospinning process to increase conjugation sites and to improve the mechanical property of vascular grafts. LMW elastic polymer improved the elasticity of the scaffolds, and significantly increased the amount of heparin conjugated to the micro/nanofibrous scaffolds, which in turn increased the loading capacity of vascular endothelial growth factor (VEGF) and prolonged the release of VEGF. Vascular grafts were implanted into the carotid artery of rats to evaluate the in vivo performance. VEGF treatment significantly enhanced endothelium formation and the overall patency of vascular grafts. Heparin coating also increased cell infiltration into the electrospun grafts, thus increasing the production of collagen and elastin within the graft wall. This work demonstrates that LMW elastic polymer blending is an approach to engineer the mechanical and biological property of micro/nanofibrous vascular grafts for in situ vascular tissue engineering.

  4. A multilayered electrospun graft as vascular access for hemodialysis.

    Directory of Open Access Journals (Sweden)

    D Radakovic

    Full Text Available Despite medical achievements, the number of patients with end-stage kidney disease keeps steadily raising, thereby entailing a high number of surgical and interventional procedures to establish and maintain arteriovenous vascular access for hemodialysis. Due to vascular disease, aneurysms or infection, the preferred access-an autogenous arteriovenous fistula-is not always available and appropriate. Moreover, when replacing small diameter blood vessels, synthetic vascular grafts possess well-known disadvantages. A continuous multilayered gradient electrospinning was used to produce vascular grafts made of collagen type I nanofibers on luminal and adventitial graft side, and poly-ɛ-caprolactone as medial layer. Therefore, a custom-made electrospinner with robust environmental control was developed. The morphology of electrospun grafts was characterized by scanning electron microscopy and measurement of mechanical properties. Human microvascular endothelial cells were cultured in the graft under static culture conditions and compared to cultures obtained from dynamic continuous flow bioreactors. Immunofluorescent analysis showed that endothelial cells form a continuous luminal layer and functional characteristics were confirmed by uptake of acetylated low-density-lipoprotein. Incorporation of vancomycin and gentamicin to the medial graft layer allowed antimicrobial inhibition without exhibiting an adverse impact on cell viability. Most striking a physiological hemocompatibility was achieved for the multilayered grafts.

  5. A multilayered electrospun graft as vascular access for hemodialysis.

    Science.gov (United States)

    Radakovic, D; Reboredo, J; Helm, M; Weigel, T; Schürlein, S; Kupczyk, E; Leyh, R G; Walles, H; Hansmann, J

    2017-01-01

    Despite medical achievements, the number of patients with end-stage kidney disease keeps steadily raising, thereby entailing a high number of surgical and interventional procedures to establish and maintain arteriovenous vascular access for hemodialysis. Due to vascular disease, aneurysms or infection, the preferred access-an autogenous arteriovenous fistula-is not always available and appropriate. Moreover, when replacing small diameter blood vessels, synthetic vascular grafts possess well-known disadvantages. A continuous multilayered gradient electrospinning was used to produce vascular grafts made of collagen type I nanofibers on luminal and adventitial graft side, and poly-ɛ-caprolactone as medial layer. Therefore, a custom-made electrospinner with robust environmental control was developed. The morphology of electrospun grafts was characterized by scanning electron microscopy and measurement of mechanical properties. Human microvascular endothelial cells were cultured in the graft under static culture conditions and compared to cultures obtained from dynamic continuous flow bioreactors. Immunofluorescent analysis showed that endothelial cells form a continuous luminal layer and functional characteristics were confirmed by uptake of acetylated low-density-lipoprotein. Incorporation of vancomycin and gentamicin to the medial graft layer allowed antimicrobial inhibition without exhibiting an adverse impact on cell viability. Most striking a physiological hemocompatibility was achieved for the multilayered grafts.

  6. Electrospun vascular grafts with anti-kinking properties

    Directory of Open Access Journals (Sweden)

    Bode M.

    2015-09-01

    Full Text Available One of the major challenges in developing appropriate vascular substitutes is to produce a graft that adapts to the biological and mechanical conditions at the application or implantation site. One approach is the use of tissue engineered electrospun grafts pre-seeded with autologous cells. However, bending stresses during in vivo applications could lead to kinking of the graft which may result in life-threatening stenosis. The aim of this study was to develop an electrospun vascular graft consisting of biodegradable polymers which can reduce or prevent kinking, due to their higher flexibility. In order to improve the bendability of the grafts, various electrospinning collectors were designed using six different patterns. Subsequently, the grafts were examined for scaffold morphology, mechanical strength and bendability. Scaffolds spun on a collector structured with a v-shaped thread (flank angle of 120° showed a homogenous and reproducible fiber deposition as compared to the unstructured reference sample. The results of the tensile tests were comparable to the unstructured reference sample, supporting the first observation. Studies on bendability were performed using a custom made flow-bending test setup. It was shown that the flow through the v-shaped grafts was reduced to less than 45 % of the reference value even after bending the graft to an angle of 140°. In contrast, the flow through an unstructured graft was reduced to more than 50 % after bending to an angle of 55°. The presented data demonstrate the need for optimizing the bendability of the commonly used electrospun vascular grafts. Using of macroscopic v-shaped collectors is a promising solution to overcome the issue of graft kinking.

  7. Hyaluronic acid enhancement of expanded polytetrafluoroethylene for small diameter vascular grafts

    Science.gov (United States)

    Lewis, Nicole R.

    Cardiovascular disease is the leading cause of mortality and morbidity in the United States and other developed countries. In the United States alone, 8 million people are diagnosed with peripheral arterial disease per year and over 250,000 patients have coronary bypass surgery each year. Autologous blood vessels are the standard graft used in small diameter (<6mm) arterial bypass procedures. Synthetic small diameter grafts have had limited success. While polyethylene (Dacron) and expanded polytetrafluoroethylene (ePTFE) are the most commonly used small diameter synthetic vascular graft materials, there are significant limitations that make these materials unfavorable for use in the low blood flow conditions of the small diameter arteries. Specifically, Dacron and ePTFE grafts display failure due to early thrombosis or late intimal hyperplasia. With the shortage of tissue donors and the limited supply of autologous blood vessels available, there is a need for a small diameter synthetic vascular graft alternative. The aim of this research is to create and characterize ePTFE grafts prepared with hyaluronic acid (HA), evaluate thrombogenic potential of ePTFE-HA grafts, and evaluate graft mechanical properties and coating durability. The results in this work indicate the successful production of ePTFE-HA materials using a solvent infiltration technique. Surface interactions with blood show increased platelet adhesion on HA-modified surfaces, though evidence may suggest less platelet activation and erythrocyte lysis. Significant changes in mechanical properties of HA-modified ePTFE materials were observed. Further investigation into solvent selection, uniformity of HA, endothelialization, and dynamic flow testing would be beneficial in the evaluation of these materials for use in small diameter vascular graft bypass procedures.

  8. Generation of Vascular Graft Biomaterials via the Modification of Polyurethane with Hyaluronic Acid

    Science.gov (United States)

    Ruiz, Amaliris

    Cardiovascular disease is the leading cause of mortality in the United States, necessitating surgical interventions such as small diameter (I.D. <6 mm) bypass grafting. Although the use of autologous veins as small diameter grafts produces favorable results, their limited availability provides a significant obstacle. Meanwhile, several synthetic materials have demonstrated success as large-diameter vascular grafts, but exhibit poor patency and high failure rates in small-diameter applications. Based on these limitations and the clinical issues associated with them, it is clear that there is a significant need to develop new materials for cardiovascular and blood-contacting applications that could be used to fabricate small-diameter vascular grafts. Thus, in this thesis we have designed and characterized a new polymer that is composed of both synthetic and natural elements with the goal of generating a material that is appropriate for use in cardiovascular applications. Specifically, we describe the modification of polyurethane (PU), a synthetic polymer with many favorable physical characteristics, with hyaluronic acid (HA), a native glycosaminoglycan that possesses anti-thrombotic properties as well as the ability to modulate endothelial cell proliferation in a molecular weight-dependent manner. The goal of the present work was to assess in detail the impact of 1) HA molecular weight, 2) HA quantity, and 3) the method of HA incorporation (bulk vs. surface-grafted) on the vascular-specific performance of polyurethane-HA (PU-HA) materials, under static conditions and upon exposure to physiological shear stresses. The initial findings presented in this thesis indicate that these PU-HA materials possess many of the physical and biological properties that are necessary for implementation in vascular applications. These materials were able to simultaneously address the three major design criteria in vascular graft fabrication: hemocompatibility, endothelialization, and

  9. Modular Small Diameter Vascular Grafts with Bioactive Functionalities.

    Directory of Open Access Journals (Sweden)

    Meik Neufurth

    Full Text Available We report the fabrication of a novel type of artificial small diameter blood vessels, termed biomimetic tissue-engineered blood vessels (bTEBV, with a modular composition. They are composed of a hydrogel scaffold consisting of two negatively charged natural polymers, alginate and a modified chitosan, N,O-carboxymethyl chitosan (N,O-CMC. Into this biologically inert scaffold two biofunctionally active biopolymers are embedded, inorganic polyphosphate (polyP and silica, as well as gelatin which exposes the cell recognition signal, Arg-Gly-Asp (RGD. These materials can be hardened by exposure to Ca(2+ through formation of Ca(2+ bridges between the polyanions, alginate, N,O-CMC, and polyP (alginate-Ca(2+-N,O-CMC-polyP. The bTEBV are formed by pressing the hydrogel through an extruder into a hardening solution, containing Ca(2+. In this universal scaffold of the bTEBV biomaterial, polycations such as poly(L-Lys, poly(D-Lys or a His/Gly-tagged RGD peptide (three RGD units were incorporated, which promote the adhesion of endothelial cells to the vessel surface. The mechanical properties of the biopolymer material (alginate-Ca(2+-N,O-CMC-polyP-silica revealed a hardness (elastic modulus of 475 kPa even after a short incubation period in CaCl2 solution. The material of the artificial vascular grafts (bTEBVs with an outer size 6 mm and 1.8 mm, and an inner diameter 4 mm and 0.8 mm, respectively turned out to be durable in 4-week pulsatile flow experiments at an alternating pressure between 25 and 100 mbar (18.7 and 75.0 mm Hg. The burst pressure of the larger (smaller vessels was 850 mbar (145 mbar. Incorporation of polycationic poly(L-Lys, poly(D-Lys, and especially the His/Gly-tagged RGD peptide, markedly increased the adhesion of human, umbilical vein/vascular endothelial cells, EA.HY926 cells, to the surface of the hydrogel. No significant effect of the polyP samples on the clotting of human plasma is measured. We propose that the metabolically

  10. [Vascular trombosis of renal graft: 9 cases].

    Science.gov (United States)

    Kaaroud, Hayet; Béji, Soumaya; Ben Hamida, Fethi; Rais, Lamia; Ben Abdallah, Taieb; El Younsi, Fethi; Ben Moussa, Fatma; Abderrahim, Ezzedine; Bardi, Rafika; Ayed, Khaled; Chebil, Mohamed; Kheder, Adel

    2008-04-01

    Allograft renal thrombosis can occur in 1 to 6% of cases. Many predisposing factors has been identified especially alteration of coagulation. We analyzed in this study frequency and predisposing factors of renal graft thrombosis. We report a retrospective study including 319 renal transplant recipients. Nine patients (2.8%) presented veinous graft thrombosis in 5 cases and arterial thombosis in 4 cases. There were 6 men and 3 women aged of 30.6 years meanly (10-56) which developed the thrombosis 6 days (1-48) after the transplantation. All patients were detransplanted after 16.2 days and 1 patient died. Thrombosis constitute an important cause of graft loss. A perfect surgical technic and prophylactic treatment in high risk patients are necessary to reduce this complication.

  11. Peritoneal pre-conditioning reduces macrophage marker expression in collagen-containing engineered vascular grafts.

    Science.gov (United States)

    Shojaee, Mozhgan; Wood, Kristin B; Moore, Lisa K; Bashur, Chris A

    2017-10-05

    Engineered vascular grafts have shown promise as arteriovenous shunts, but they have not yet progressed to clinical trials for coronary arteries synthetic material, poly(ε-caprolactone), to modulate the post-grafting inflammatory response while avoiding aneurysmal-like dilation and failure that can occur with pure collagen grafts. We also used pre-implantation in an "in vivo bioreactor" to recruit autologous cells and improve patency after grafting. Electrospun conduits were pre-implanted within rat peritoneal cavities and then grafted autologously into abdominal aortae. Conduit collagen percentages and pre-implantation were tested for their impact on graft remodeling and patency. Burst pressures >2000 mmHg, reproducible expansion with systole/diastole, and maintenance of mechanical integrity were observed. More importantly, peritoneal pre-implantation reduced overall lipid oxidation, intimal layer thickness, and expression of an M1 macrophage marker. The condition with the most collagen, 25%, exhibited the lowest expression of macrophage markers but also resulted in a thicker intimal layer. Overall, the 10% collagen/PCL with peritoneal pre-implantation condition appeared to exhibit the best combination of responses, and may result in improved clinical graft viability. This manuscript describes a rodent study to systematically determine the benefits of both pre-implantation in the peritoneal cavity and specific ratios of collagen on engineered vascular graft viability. We show that pre-implantation had a significant benefit, including decreasing the expression of macrophage markers and reducing lipid oxidation after grafting. This study is the first time that the benefits of peritoneal pre-implantation have been compared to an "off the shelf," directly grafted control condition. We also demonstrated the importance of specific collagen ratio on the response after grafting. Overall, we feel that this article will be of interest to the field and it has the

  12. Experimental vascular graft for liver transplantation

    NARCIS (Netherlands)

    Kobori, L; Nemeth, T; Nemes, B; Dallos, G; Sotonyi, P; Fehervari, [No Value; Patonai, A; Slooff, MJH; Jaray, J; De Jong, KP

    2003-01-01

    Hepatic artery thrombosis is a major cause of graft failure in liver transplantation. Use of donor interponates are common, but results are controversial because of necrosis or thrombosis after rejection. Reperfusion injury, hypoxia and free radical production determinate the survival. The aim of

  13. Concise Review: Tissue-Engineered Vascular Grafts for Cardiac Surgery: Past, Present, and Future

    OpenAIRE

    Kurobe, Hirotsugu; Maxfield, Mark W.; Breuer, Christopher K.; Shinoka, Toshiharu

    2012-01-01

    Developing a durable material with the potential to function with child growth will eliminate the need for reoperation and significantly reduce morbidity and mortality in some types of congenital heart defects. Tissue-engineered vascular grafts offer the ability to drastically improve morbidity and mortality and drastically improve the quality of life of patients after congenital heart defect surgery.

  14. Evaluation of synthetic vascular grafts in a mouse carotid grafting model.

    Directory of Open Access Journals (Sweden)

    Alex H P Chan

    Full Text Available Current animal models for the evaluation of synthetic grafts are lacking many of the molecular tools and transgenic studies available to other branches of biology. A mouse model of vascular grafting would allow for the study of molecular mechanisms of graft failure, including in the context of clinically relevant disease states. In this study, we comprehensively characterise a sutureless grafting model which facilitates the evaluation of synthetic grafts in the mouse carotid artery. Using conduits electrospun from polycaprolactone (PCL we show the gradual development of a significant neointima within 28 days, found to be greatest at the anastomoses. Histological analysis showed temporal increases in smooth muscle cell and collagen content within the neointima, demonstrating its maturation. Endothelialisation of the PCL grafts, assessed by scanning electron microscopy (SEM analysis and CD31 staining, was near complete within 28 days, together replicating two critical aspects of graft performance. To further demonstrate the potential of this mouse model, we used longitudinal non-invasive tracking of bone-marrow mononuclear cells from a transgenic mouse strain with a dual reporter construct encoding both luciferase and green fluorescent protein (GFP. This enabled characterisation of mononuclear cell homing and engraftment to PCL using bioluminescence imaging and histological staining over time (7, 14 and 28 days. We observed peak luminescence at 7 days post-graft implantation that persisted until sacrifice at 28 days. Collectively, we have established and characterised a high-throughput model of grafting that allows for the evaluation of key clinical drivers of graft performance.

  15. 21 CFR 870.3450 - Vascular graft prosthesis.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vascular graft prosthesis. 870.3450 Section 870.3450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... animal origin, including human umbilical cords. (b) Classification. Class II (special controls). The...

  16. Brief report: biomarkers of aortic vascular prosthetic graft infection in a porcine model with Staphylococcus aureus

    DEFF Research Database (Denmark)

    Langerhuus, S. N.; Tønnesen, E. K.; Jensen, K. H.

    2010-01-01

    Aortic vascular prosthetic graft infection (AVPGI) with Staphylococcus aureus is a feared post-operative complication. This study was conducted to evaluate the clinical signs and potential biomarkers of infection in a porcine AVPGI model. The biomarkers evaluated were: C-reactive protein (CRP......), fibrinogen, white blood cells (WBC), major histocompatibility complex II (MHC II) density, lymphocyte CD4:CD8 ratio and tumour necrosis factor-alpha (TNF-α) in vitro responsiveness. Sixteen pigs were included in the study, and randomly assigned into four groups (n = 4): “SHAM” pigs had their infra-renal...... aorta exposed by laparotomy; “CLEAN” pigs had an aortic graft inserted; “LOW” and “HIGH” pigs had an aortic graft inserted and, subsequently, S. aureus were inoculated on the graft material (5 × 104 colony-forming units [CFU] and 1 × 106 CFU, respectively). Biomarkers were evaluated prior to surgery...

  17. Aortic Graft Infection: Graphene Shows the Way to an Infection-Resistant Vascular Graft

    Directory of Open Access Journals (Sweden)

    Nikolaos Patelis

    2017-05-01

    Full Text Available Aortic graft infection is a potentially lethal complication of open and endovascular repair of aortic aneurysms. Graphene is the only existing two-dimensional material, and its unique structure gives graphene and its derivatives a plethora of original characteristics. Among other characteristics, graphene demonstrates bacteriostatic and bactericidal effects that could potentially resolve the problem of graft infection in the future. Data already exist in literature supporting this antibacterial effect of graphene oxide and reduced graphene oxide. Combining these materials with other substances enhances the antibacterial effect. Additionally, it looks feasible to expect antibiotic-delivering graphene-based graft materials in the future. Based on already published data, we could conclude that regarding graphene and its derivatives, the blessing of bactericidal effect comes with the curse of human cells toxicity. Therefore, it is important to find a fine balance between the desired antibacterial and the adverse cytotoxic effect before graphene is used in graft materials for humans.

  18. The blood and vascular cell compatibility of heparin-modified ePTFE vascular grafts

    Science.gov (United States)

    Hoshi, Ryan A.; Van Lith, Robert; Jen, Michele C.; Allen, Josephine B.; Lapidos, Karen A.; Ameer, Guillermo

    2014-01-01

    Prosthetic vascular grafts do not mimic the antithrombogenic properties of native blood vessels and therefore have higher rates of complications that involve thrombosis and restenosis. We developed an approach for grafting bioactive heparin, a potent anticoagulant glycosaminoglycan, to the lumen of ePTFE vascular grafts to improve their interactions with blood and vascular cells. Heparin was bound to aminated poly(1,8-octanediol-co-citrate) (POC) via its carboxyl functional groups onto POC-modified ePTFE grafts. The bioactivity and stability of the POC-immobilized heparin (POC–Heparin) were characterized via platelet adhesion and clotting assays. The effects of POC–Heparin on the adhesion, viability and phenotype of primary endothelial cells (EC), blood outgrowth endothelial cells (BOECs) obtained from endothelial progenitor cells (EPCs) isolated from human peripheral blood, and smooth muscle cells were also investigated. POC–Heparin grafts maintained bioactivity under physiologically relevant conditions in vitro for at least one month. Specifically, POC–Heparin-coated ePTFE grafts significantly reduced platelet adhesion and inhibited whole blood clotting kinetics. POC–Heparin supported EC and BOEC adhesion, viability, proliferation, NO production, and expression of endothelial cell-specific markers von Willebrand factor (vWF) and vascular endothelial-cadherin (VE-cadherin). Smooth muscle cells cultured on POC–Heparin showed increased expression of α-actin and decreased cell proliferation. This approach can be easily adapted to modify other blood contacting devices such as stents where antithrombogenicity and improved endothelialization are desirable properties. PMID:23069711

  19. Manufacture and property research of heparin grafted electrospinning PCU artificial vascular scaffolds.

    Science.gov (United States)

    Li, Qing; Mu, Lanlan; Zhang, Fenghua; Mo, Zhichao; Jin, Chuanyu; Qi, Weiguo

    2017-09-01

    PCU (polycarbonate polyurethane) is supposed to be an ideal elastomer for manufacturing artificial vessel scaffold with perfect mechanical strength and biocompatibility. Surface grafting by heparin sodium can increase its anticoagulant hemorrhagic, achieving a better application in artificial vessels. Artificial vessels were preliminarily prepared by electrostatic spinning, treated by NH3 plasma and cross-linked with the anticoagulant heparin sodium chemically. Performances of the PCU-Hep (heparin sodium grafted purethane artificial vessels) artificial vessel were calculated through the physical and chemical property tests, evaluation of blood and biocompatibility. Results manifested that heparin sodium was successfully grafted to the vascular surface, porosity, pore diameter and water permeability of the vascular prosthesis fitted the requirements of artificial vessels, the blood test results demonstrated that the vascular material had a low hemolysis, in vitro cytotoxicity experiment and animal experiments proved an excellent biocompatibility. Thus the heparin sodium grafted electrospinning vessels could reduce intravascular thrombus and had potential clinical application. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. A FTIR characterization of a haemocompatible material obtained by swift heavy ion radiation grafting

    Energy Technology Data Exchange (ETDEWEB)

    Dapoz, S.; Betz, N.; Le Moel, A. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Recherche sur l`Etat Condense, les Atomes et les Molecules

    1996-01-01

    In order to prepare materials destined to be used as vascular prothesis, a radiation grafting of styrene, induced by swift heavy ions in polyvinylidene fluoride films, was performed. A substitution of the grafted polystyrene with sulfonate and aspartic acid sulfamide groups, which confers to the polymer anticoagulant properties, was achieved. The material was characterized by Fourier Transform Infrared spectroscopy at each step of the synthesis. (authors). 5 refs., 2 figs.

  1. 21 CFR 872.3930 - Bone grafting material.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3930 Bone grafting material. (a) Identification... “Class II Special Controls Guidance Document: Dental Bone Grafting Material Devices.” (See § 872.1(e) for... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bone grafting material. 872.3930 Section 872.3930...

  2. Vascularized pedicle graft of ipsilateral fibula for recurrent congenital pseudoarthrosis of the tibia

    Directory of Open Access Journals (Sweden)

    Seyed Esmail Hassanpour

    2007-07-01

    Full Text Available

    We have performed the ipsilateral vascularized fibular transfer for the treatment of congenital pseudoarthrosis of the tibia (CPT. In the case under study, the conventional treatment by intramedullary rod and autogenous iliac bone grafting had failed. The follow up took place during the next 4 years and the patient can now walk without assistance. Combining a pedicle ipsilateral fibular transfer with an internal fixation and iliac bone graft may be a good option for the treatment of congenital pseudoarthrosis of tibia.
    KEY WORDS: Congenital pseudoarthrosis, tibia, vascularized fibular graft, bone graft.

  3. Non-Vascularized Autogenous Bone Grafts for Reconstruction of Maxillofacial Osseous Defects.

    Science.gov (United States)

    Ahmed, Waseem; Asim, Muhammad Adil; Ehsan, Afeefa; Abbas, Qalab

    2018-01-01

    To determine the outcomes of non-vascularized bone grafts for reconstruction of maxillofacial defects. Case series. Department of Oral and Maxillofacial Surgery, Armed Forces Institute of Dentistry, Rawalpindi, from January 2013 to December 2015. Descriptive analyses of 30 patients, who underwent maxillofacial reconstruction with non-vascularized bone grafts, were conducted. The demographic information, diagnosis, and type of graft harvested to reconstruct the defect were statistically analyzed. Outcomes of reconstruction with non-vascularized bone grafts were analyzed in terms of mouth opening, success of dental rehabilitation, and postoperative complications, i.e. surgical site infection and hardware loosening. A total of 30 patients ranging from 8 to 60 years (33.57 ±14.74 years) had maxillofacial defects reconstructed mostly due to gunshot injuries, followed by post-resection defects. Overall 15 cases (50%) were reconstructed with iliac crest cortico-cancellous bone graft, 11 cases (36.7%) with rib; while in four cases (13.3%), costochondral graft was used for reconstruction. In 26 cases (86.7%), graft was found to be successful. In three cases, re-operation for onlay bone graft was required to provide optimal dental rehabilitation; while in just one case, postoperative surgical site infection was observed. Non-vascularized bone grafts provide a reasonable and effective modality for reconstruction of maxillofacial defects.

  4. Engineering the Biomaterial Interface of Prosthetic Vascular Grafts for Improving Thromboresistance and Biocompatibility

    Science.gov (United States)

    Hoshi, Ryan Akihiro

    The purpose of this dissertation is to develop novel biomaterials as therapies for treating cardiovascular disease. The first and second aims describe the creation of a new and facile approach for grafting bioactive heparin to the surface of expanded polytetrafluoroethylene (ePTFE) vascular grafts using a thermally cross-linked poly(1,8 octanediol-co-citric acid) (POC) elastomer. The POC immobilized heparin (POC-Heparin) demonstrated excellent long term stability under physiological conditions for up to one month and significantly reduced platelet adhesion and maintained bioactive inhibition of whole blood clotting kinetics. POC-Heparin supported endothelial cell viability, proliferation, nitric oxide production and expression of endothelial cell specific markers von Willebrand factor and vascular endothelial-cadherin. This material was also capable of affecting vascular smooth muscle cell phenotype via increased expression of alpha-actin and decreased cell growth. The POC-Heparin coating is capable of significantly improving vascular graft thromboresistance, supporting endothelialization and inhibiting vascular smooth muscle cell growth. This coating technology can be easily adapted to modify other blood contacting devices for simultaneously reducing thrombogenicity and improving endothelialization. Lastly, the third aim details the initial steps for developing materials which are capable of providing sustained release of bioactive signaling molecules such as stromal derived factor-1alpha (SDF-1) to promote recruitment of stem/progenitor cells. A copolymer based on citric acid, polyethylene glycol and N-isopropylacrylamide (CPN) was synthesized with enhanced electronegative charge and gelation properties for controlling SDF-1 protein encapsulation and delivery. Upon CPN gelation at 37°C, SDF-1 protein can be encapsulated with near 100% efficiency and deliver protein for up to 3 weeks. Using isolated blood outgrowth endothelial cells (BOECs) from human peripheral

  5. Construction and biofunctional evaluation of electrospun vascular graft loaded with selenocystamine for in situ catalytic generation of nitric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Siyuan; An, Jun; Weng, Lei [State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Bioactive Materials for Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071 (China); Li, Yandong [Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071 (China); Xu, Han; Wang, Yaping; Ding, Dan; Kong, Deling [State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Bioactive Materials for Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071 (China); Wang, Shufang, E-mail: wangshufang@nankai.edu.cn [State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Bioactive Materials for Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071 (China)

    2014-12-01

    Construction and biofunctional evaluation of a novel vascular graft with in situ catalytic generation of nitric oxide were described in this paper. Poly α-lysine and poly (γ-glutamic acid) were deposited alternately onto the surface of an electrospun poly ε-caprolactone matrix via electrostatic layer-by-layer self-assembly, and then selenocystamine was loaded as a catalyst. Measurement of in vitro catalytic generation of nitric oxide demonstrated that this catalyst-loaded material could considerably accelerate the release of nitric oxide from S-nitrosoglutathione. A fibroblast proliferation assay showed that the material possessed satisfactory cellular compatibility. The catalyst-loaded material could inhibit the spread of smooth muscle cells in the presence of nitric oxide donors. In arteriovenous-shunt experiment, the catalyst-loaded graft exhibited good anti-thrombotic property where it could prevent acute thrombosis by decreasing the adhesion and activation of platelets and other blood cells. These data suggest a new method of building vascular grafts with improved hemocompatibility and biological functions. - Highlights: • A porous small-diameter vascular graft was prepared by electrospinning. • Selenocystamine was loaded for in situ catalytic and sustained NO generation. • There was a significant catalytic NO generation on the catalyst-loaded sample. • The spread of smooth muscle cells was inhibited on the catalyst-loaded sample. • The catalyst-loaded sample showed anti-thrombotic property in AV-shunt experiment.

  6. Multimodality imaging of normal hepatic transplant vasculature and graft vascular complications

    National Research Council Canada - National Science Library

    Roberts, Jeffrey H; Mazzariol, Fernanda S; Frank, Susan J; Oh, Sarah K; Koenigsberg, Mordecai; Stein, Marjorie W

    2011-01-01

    .... Post-operative complications, however, can limit this success. Ultrasound is the primary imaging modality for evaluation of hepatic transplants, providing real-time information about vascular flow in the graft...

  7. Use of non-vascularized autologous fibula strut graft in the treatment ...

    African Journals Online (AJOL)

    Background: Fractures resulting in segmental bone loss challenge the orthopedic surgeon. Orthopedic surgeons in developed countries have the option of choosing vascularized bone transfers, bone transport, allogenic bone grafts, bone graft substitutes and several other means to treat such conditions. In developing ...

  8. Multimodality Imaging of Normal Hepatic Transplant Vasculature and Graft Vascular Complications

    Directory of Open Access Journals (Sweden)

    Jeffrey H Roberts

    2011-01-01

    Full Text Available Orthotopic liver transplantation is an important treatment option for patients with end-stage liver disease. Advances in surgical technique, along with improvements in organ preservation and immunosuppression have improved patient outcomes. Post-operative complications, however, can limit this success. Ultrasound is the primary imaging modality for evaluation of hepatic transplants, providing real-time information about vascular flow in the graft. Graft vascular complications are not uncommon, and their prompt recognition is crucial to allow for timely graft salvage. A multimodality approach including CT angiography, MRI, or conventional angiography may be necessary in cases of complex transplant vascular anatomy or when sonography and Doppler are inconclusive to diagnose the etiologies of these complications. The purpose of this article is to familiarize radiologists with the normal post-transplant vascular anatomy and the imaging appearances of the major vascular complications that may occur within the hepatic artery, portal vein, and venous outflow tract, with an emphasis on ultrasound.

  9. Laser-induced shock waves enhance sterilization of infected vascular prosthetic grafts.

    Science.gov (United States)

    Nigri, G R; Tsai, S; Kossodo, S; Waterman, P; Fungaloi, P; Hooper, D C; Doukas, A G; LaMuraglia, G M

    2001-01-01

    Bacteria that cause infection of vascular prosthetic grafts produce an exopolysaccharide matrix known as biofilm. Growth in biofilms protects the bacteria from leukocytes, antibodies and antimicrobial drugs. Laser-generated shock waves (SW) can disrupt biofilms and increase drug penetration. This study investigates the possibility of increasing antibiotic delivery and sterilization of vascular prosthetic graft. Strains of Staphylococcus epidermidis and S. aureus were isolated from infected prosthetic grafts obtained directly from patients. Dacron grafts were inoculated with the isolated bacteria, which were allowed to form adherent bacterial colonies. The colonized grafts underwent the following treatments: (a) antibiotic (vancomycin) alone; (b) antibiotic and SW (c) saline only; and (d) saline and SW. Six hours after treatment, the grafts were sonicated, the effluent was cultured and the colony forming units (CFU) were counted. CFU recovered from control grafts colonized by S. epidermidis were comparable: saline, 3.05 x 10(8) and saline+SW 3.31 x 10(8). The number of S. epidermidis CFU diminished to 7.61 x 10(6) after antibiotic treatment but the combined antibiotic+SW treatment synergistically decreased CFU number to 1.27 x 10(4) (Plaser-generated shock waves have no effects alone, but can enhance the effectiveness of antibiotics against bacteria associated with prosthetic vascular graft biofilms, suggesting that this treatment may be of value as adjunctive therapy for prosthetic graft infections.

  10. Vascular Graft Impregnation with Antibiotics: The Influence of High Concentrations of Rifampin, Vancomycin, Daptomycin, and Bacteriophage Endolysin HY-133 on Viability of Vascular Cells.

    Science.gov (United States)

    Herten, Monika; Idelevich, Evgeny A; Sielker, Sonja; Becker, Karsten; Scherzinger, Anna S; Osada, Nani; Torsello, Giovanni B; Bisdas, Theodosios

    2017-06-27

    BACKGROUND Rifampin-soaked synthetic prosthetic grafts have been widely used for prevention or treatment of vascular graft infections (VGIs). This in vitro study investigated the effect of the antibiotics daptomycin and vancomycin and the new recombinant bacteriophage endolysin HY-133 on vascular cells, as potential alternatives compared to rifampin. MATERIAL AND METHODS Primary human ECs, vascular smooth muscle cells (vSMC), and fibroblasts were cultivated in 96-well plates and incubated with rifampin, daptomycin, vancomycin, and endolysin HY-133 for 24 h. Subsequently, after washing, cell viability was determined by measuring mitochondrial ATP concentration. Antibiotics were used in their corresponding minimum and maximum serum concentrations, in decimal multiples and in maximum soaking concentration. The experiments were performed in triplicate. RESULTS The 10-fold max serum concentrations of rifampin, daptomycin, and vancomycin did not influence viability of EC and vSMC (100 µg/ml, p>0.170). Higher concentrations of rifampin (>1 mg/ml) significantly (pEndolysin did not display any cytotoxicity towards vascular cells. CONCLUSIONS Results of this in vitro study show the high cytotoxicity of rifampin against vascular cells, and may re-initiate the discussion about the benefit of prophylactic pre-soaking in high concentrations of rifampin. Further studies are necessary to determine the influence of rifampin on the restoration of vessel functionality versus its prophylactic effect against VGIs. Future use of recombinant phage endolysins for alternative prophylactic strategies needs further investigations.

  11. Polyhydroxybutyrate/valerate/polycaprolactone small-diameter vascular graft: Experimental study of integration into organism

    Science.gov (United States)

    Antonova, L. V.; Burago, A. Yu.; Mironov, A. V.; Matveeva, V. G.; Velikanova, E. A.; Mukhamadiyarov, R. A.; Glushkova, T. V.; Kudryavtseva, Y. A.; Barbarash, O. L.; Barbarash, L. S.

    2015-10-01

    We prepared polyhydroxybutyrate/valerate (PHBV)/polylcaprolactone (PCL) small-diameter vascular grafts using electrospinning. Surface structure was assessed by scanning electron microscopy whilst physicomechanical properties were investigated by longitudinal uniaxial tension testing. Patency of grafts implanted into the rat abdominal aorta was evaluated using a Doppler ultrasonography at 2 week, 1 month and 12 month postimplantation. In addition, we assessed local histological features, along with IL-1β, IL-2, IL-4, IL-10, TNFa, TGF-β1, and VEGF serum levels. We revealed that only 2 (25%) grafts were not thrombosed at 2 week and 1 month postimplantation. However, at 12 month postimplantation a satisfactory histological pattern was observed in 50% of all cases, and we detected a monolayer of endothelial cells on the inner graft surface in half the cases. Regarding other grafts, we revealed minor connective tissue hyperplasia in 41.7% of the grafts and an inflammatory infiltrate in the part of the arterial wall in 8.3% of the grafts. We found that the IL-1β serum level was 3.5-fold higher in the group of experimental rats at 12 month postimplantation (p IL-10 serum level at 1 and 12 month postimplantation was more than 100-fold higher in comparison with 2 week postimplantation and control rats (p < 0.001). Serum VEGF was detected only at 12 month postimplantation. All in all, we created a biocompatible PHBV/PCL small-diameter vascular graft with a high surface area to volume ratio. A long-term patency of biodegradable vascular grafts after implantation into the rat abdominal aorta and the absence of a considerable immune response confirmed a high biocompatibility of such construct and the possibility of its use as a vascular graft.

  12. Materials for engineering vascularized adipose tissue.

    Science.gov (United States)

    Chiu, Yu-Chieh; Cheng, Ming-Huei; Uriel, Shiri; Brey, Eric M

    2011-05-01

    Loss of adipose tissue can occur due to congenital and acquired lipoatrophies, trauma, tumor resection, and chronic disease. Clinically, it is difficult to regenerate or reconstruct adipose tissue. The extensive microvsacular network present in adipose, and the sensitivity of adipocytes to hypoxia, hinder the success of typical tissue transfer procedures. Materials that promote the formation of vascularized adipose tissue may offer alternatives to current clinical treatment options. A number of synthetic and natural biomaterials common in tissue engineering have been investigated as scaffolds for adipose regeneration. While these materials have shown some promise they do not account for the unique extracellular microenvironment of adipose. Adipose derived hydrogels more closely approximate the physical and chemical microenvironment of adipose tissue, promote preadipocyte differentiation and vessel assembly in vitro, and stimulate vascularized adipose formation in vivo. The combination of these materials with techniques that promote rapid and stable vascularization could lead to new techniques for engineering stable, vascularized adipose tissue for clinical application. In this review we discuss materials used for adipose tissue engineering and strategies for vascularization of these scaffolds. Materials that promote formation of vascularized adipose tissue have the potential to serve as alternatives or supplements to existing treatment options, for adipose defects or deficiencies resulting from chronic disease, lipoatrophies, trauma, and tumor resection. Copyright © 2009 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

  13. Synthesis and characterization of polycaprolactone urethane hollow fiber membranes as small diameter vascular grafts

    Energy Technology Data Exchange (ETDEWEB)

    Mercado-Pagán, Ángel E. [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Stahl, Alexander M. [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Department of Chemistry, Stanford University, Stanford, CA (United States); Ramseier, Michelle L. [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Department of Chemical Engineering, Stanford University, Stanford, CA (United States); Behn, Anthony W. [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Yang, Yunzhi, E-mail: ypyang@stanford.edu [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States); Department of Bioengineering, Stanford University, Stanford, CA (United States)

    2016-07-01

    The design of bioresorbable synthetic small diameter (< 6 mm) vascular grafts (SDVGs) capable of sustaining long-term patency and endothelialization is a daunting challenge in vascular tissue engineering. Here, we synthesized a family of biocompatible and biodegradable polycaprolactone (PCL) urethane macromers to fabricate hollow fiber membranes (HFMs) as SDVG candidates, and characterized their mechanical properties, degradability, hemocompatibility, and endothelial development. The HFMs had smooth surfaces and porous internal structures. Their tensile stiffness ranged from 0.09 to 0.11 N/mm and their maximum tensile force from 0.86 to 1.03 N, with minimum failure strains of approximately 130%. Permeability varied from 1 to 14 × 10{sup −6} cm/s, burst pressures from 1158 to 1468 mm Hg, and compliance from 0.52 to 1.48%/100 mm Hg. The suture retention forces ranged from 0.55 to 0.81 N. HFMs had slow degradation profiles, with 15 to 30% degradation after 8 weeks. Human endothelial cells proliferated well on the HFMs, creating stable cell layer coverage. Hemocompatibility studies demonstrated low hemolysis (< 2%), platelet activation, and protein adsorption. There were no significant differences in the hemocompatibility of HFMs in the absence and presence of endothelial layers. These encouraging results suggest great promise of our newly developed materials and biodegradable elastomeric HFMs as SDVG candidates. - Highlights: • Polyester urethane hollow fiber membranes (HFMs) were fabricated and evaluated. • HFM properties varied according to composition. • HFM inner and outer surfaces were successfully seeded with cells. • HFMs showed excellent hemocompatibility in vitro. • HFM has the potential to be used for small diameter vascular grafts.

  14. Acellular Endocardium as a Novel Biomaterial for the Intima of Tissue-Engineered Small-Caliber Vascular Grafts.

    Science.gov (United States)

    Wang, Feng; Guan, Xin; Wu, TianYi; Qiao, JianOu; Han, ZhaoQing; Wu, JinLong; Yu, XiaoWei; You, QingJun

    2016-12-01

    We aimed to investigate whether acellular endocardium can be used as a useful biomaterial for the intima of engineered small-caliber vascular grafts. Fresh endocardium was harvested from the swine left atrium and was decellularized by digestion with the decellularization solution of Triton X-100 and SDS containing DNase I and RNase A. Surface morphological characteristics and Young's modulus were evaluated. To analyze the effect of mechanical characteristics on cell adhesion, the decellularized endocardium was stiffened with 2.5% glutaraldehyde. Small-caliber vascular grafts were constructed using decellularized endocardium treated with or without glutaraldehyde as the intima. CD34+ cells were seeded onto the luminal surface of the vascular grafts and linked to bioreactors that simulate a pulsatile blood stream. Acellular endocardium had distinct surface morphological characteristics, which were quite different from those of other materials. The compliance of acellular endocardium was higher than that of other materials tested by Young's modulus. CD34+ cells formed a monolayer structure and adhered to the inner face of the acellular endocardium. The glutaraldehyde treatment stiffened the acellular endocardium but had little impact on the surface morphological characteristics or static adhesiveness of the cells. Data from the bioreactor study showed that the detachment of the cells from the surface of glutaraldehyde-treated acellular endocardium increased dramatically when the pressure was equal or higher than 40 mm Hg, while the cells on the untreated acellular endocardium remained well and formed confluent monolayers and tight junctions under the same pressure. Acellular endocardium has distinct structures and mechanical characteristics that are beneficial for CD34+ cell adhesion and retention under dynamic fluid perfusion. Thus, it can be used as a useful biomaterial for the construction of the intima of engineered small-caliber vascular grafts. Copyright © 2016

  15. Reduction of indium-111 platelet deposition on Dacron vascular grafts in humans by aspirin plus dipyridamole

    Energy Technology Data Exchange (ETDEWEB)

    Stratton, J.R.; Ritchie, J.L.

    1986-02-01

    Aspirin plus dipyridamole reduces platelet accumulation on short-term Dacron vascular grafts in man. To determine whether drug inhibition of platelet deposition is sustained on older grafts, we studied 18 men aged 41 to 87 years who had Dacron aortic bifurcation grafts in place a mean of 43.4 months (range 9.8 to 121.0) before and during short-term therapy with aspirin (325 mg tid) plus dipyridamole (75 mg tid). During both the baseline and drug studies, indium-111 (/sup 111/In) platelet deposition was quantitated by two techniques, standard planar imaging performed at 24, 48, and 72 hr after injection of platelets and single photon emission computed tomographic imaging performed at 24 and 72 hr after injection. All analyses were performed in a blinded fashion. On both the planar and tomographic images, platelet accumulation on the graft was quantitated by a graft/blood ratio that compared activity in the graft to simultaneously collected whole blood /sup 111/In platelet activity. Aspirin plus dipyridamole reduced the tomographic graft/blood ratio at 24 hr (20.6 +/- 3.5 vs 17.3 +/- 2.5) (+/-SEM) and at 72 hr (29.0 +/- 4.8 vs 25.0 +/- 4.1) after injection of platelets (p = .02). Dacron vascular grafts. Similarly, the planar graft/blood ratio was reduced at 24 hr (2.7 +/- 0.5 vs 2.4 +/- 0.5), 48 hr (3.7 +/- 0.9 vs 3.1 +/- 0.7), and 72 hr (4.0 +/- 0.9 vs 3.6 +/- 0.8) (p = .04). We conclude that aspirin (325 mg tid) plus dipyridamole (75 mg tid) reduces platelet accumulation on long-term Dacron vascular grafts.

  16. Vascularized connective tissue flap for bone graft coverage.

    Science.gov (United States)

    Herford, Alan S; Cooper, Todd C; Maiorana, Carlo; Cicciù, Marco

    2011-04-01

    Alveolar defects are characterized by missing soft and hard tissues. It is often necessary to combine secondary procedures to address the soft-tissue component. The authors describe a technique that uses a split-thickness flap design that is placed over the crest of the remaining ridge and extends in a palatal direction. This allows advancement of the flap with its exposed connective tissue over the bone graft and provides restoration of both bone and keratinized tissue. Seventeen patients with defects involving the anterior maxilla who required grafting procedures were including in this study. All patients had an autogenous bone graft (n  =  17) combined with osseointegrated implants (n  =  41). A split-thickness flap design was used at the time of bone graft placement (primary) in 9 patients and at the time of implant uncovering (secondary) in 8 patients. There were no cases of flap necrosis or dehiscence with exposure of the bone graft. All patients demonstrated an increase in keratinized tissue involving the peri-implant area. An apical repositioned split-thickness flap provides an increased zone of keratinized tissue with improved esthetics and implant maintenance. This technique can be performed simultaneously with the grafting procedure, thus avoiding extensive undermining of the adjacent soft tissue.

  17. Aneurysmal angiosarcoma associated with vascular graft revealed by 18F-FDG-PET imaging.

    Science.gov (United States)

    Chetouani, Ahmed; Perrin, Mathieu; Drouet, Clément; Marie, Pierre-Yves; Verger, Antoine

    2017-06-01

    We report a rare case of vascular graft-associated aneurysmal angiosarcoma by 18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET). An 81-year-old male patient, with a prior history of graft interposition 1 year previously, was referred to 18F-FDG-PET because of an inflammatory syndrome of unknown origin. FDG-PET images revealed a particular pattern of intense circular uptake within the arterial wall (SUVmax = 10) in a popliteal aneurysm and, additionally, a large hypermetabolic mass centered by the graft. Remote hypermetabolisms in lung nodules and pleural thickenings were also detected. The diagnosis of angiosarcoma was ascertained through histopathological analysis of surgical samples. Development of an aneurysmal angiosarcoma at the site of a vascular graft is a rare entity, often misdiagnosed. 18F-FDG-PET appears to be useful in its detection with a PET pattern of intense circular uptake within the arterial wall. Such finding should lead to the search for distant metastasis.

  18. Development of Non-Cell Adhesive Vascular Grafts Using Supramolecular Building Blocks.

    Science.gov (United States)

    van Almen, Geert C; Talacua, Hanna; Ippel, Bastiaan D; Mollet, Björne B; Ramaekers, Mellany; Simonet, Marc; Smits, Anthal I P M; Bouten, Carlijn V C; Kluin, Jolanda; Dankers, Patricia Y W

    2016-03-01

    Cell-free approaches to in situ tissue engineering require materials that are mechanically stable and are able to control cell-adhesive behavior upon implantation. Here, the development of mechanically stable grafts with non-cell adhesive properties via a mix-and-match approach using ureido-pyrimidinone (UPy)-modified supramolecular polymers is reported. Cell adhesion is prevented in vitro through mixing of end-functionalized or chain-extended UPy-polycaprolactone (UPy-PCL or CE-UPy-PCL, respectively) with end-functionalized UPy-poly(ethylene glycol) (UPy-PEG) at a ratio of 90:10. Further characterization reveals intimate mixing behavior of UPy-PCL with UPy-PEG, but poor mechanical properties, whereas CE-UPy-PCL scaffolds are mechanically stable. As a proof-of-concept for the use of non-cell adhesive supramolecular materials in vivo, electrospun vascular scaffolds are applied in an aortic interposition rat model, showing reduced cell infiltration in the presence of only 10% of UPy-PEG. Together, these results provide the first steps toward advanced supramolecular biomaterials for in situ vascular tissue engineering with control over selective cell capturing. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Development and in vivo validation of tissue-engineered, small-diameter vascular grafts from decellularized aortae of fetal pigs and canine vascular endothelial cells

    Directory of Open Access Journals (Sweden)

    Xu Ma

    2017-11-01

    Full Text Available Abstract Background Tissue engineering has emerged as a promising alternative for small-diameter vascular grafts. The aim of this study was to determine the feasibility of using decellularized aortae of fetal pigs (DAFPs to construct tissue-engineered, small-diameter vascular grafts and to test the performance and application of DAFPs as vascular tissue-engineered scaffolds in the canine arterial system. Methods DAFPs were prepared by continuous enzymatic digestion. Canine vascular endothelial cells (ECs were seeded onto DAFPs in vitro and then the vascular grafts were cultured in a custom-designed vascular bioreactor system for 7 days of dynamic culture following 3 days of static culture. The grafts were then transplanted into the common carotid artery of the same seven dogs from which ECs had been derived (two grafts were prepared for each dog with one as a backup; therefore, a total of 14 tissue-engineered blood vessels were prepared. At 1, 3, and 6 months post-transplantation, ultrasonography and contrast-enhanced computed tomography (CT were used to check the patency of the grafts. Additionally, vascular grafts were sampled for histological and electron microscopic examination. Results Tissue-engineered, small-diameter vascular grafts can be successfully constructed using DAFPs and canine vascular ECs. Ultrasonographic and CT test results confirmed that implanted vascular grafts displayed good patency with no obvious thrombi. Six months after implantation, the grafts had been remodeled and exhibited a similar structure to normal arteries. Immunohistochemical staining showed that cells had evenly infiltrated the tunica media and were identified as muscular fibroblasts. Scanning electron microscopy showed that the graft possessed a complete cell layer, and the internal cells of the graft were confirmed to be ECs by transmission electron microscopy. Conclusions Tissue-engineered, small-diameter vascular grafts constructed using DAFPs and

  20. Molecular imaging of vascular endothelial growth factor receptors in graft arteriosclerosis.

    Science.gov (United States)

    Zhang, Jiasheng; Razavian, Mahmoud; Tavakoli, Sina; Nie, Lei; Tellides, George; Backer, Joseph M; Backer, Marina V; Bender, Jeffrey R; Sadeghi, Mehran M

    2012-08-01

    Vascular endothelial growth factor (VEGF) signaling plays a key role in the pathogenesis of vascular remodeling, including graft arteriosclerosis. Graft arteriosclerosis is the major cause of late organ failure in cardiac transplantation. We used molecular near-infrared fluorescent imaging with an engineered Cy5.5-labeled single-chain VEGF tracer (scVEGF/Cy) to detect VEGF receptors and vascular remodeling in human coronary artery grafts by molecular imaging. VEGF receptor specificity of probe uptake was shown by flow cytometry in endothelial cells. In severe combined immunodeficiency mice, transplantation of human coronary artery segments into the aorta followed by adoptive transfer of allogeneic human peripheral blood mononuclear cells led to significant neointima formation in the grafts over a period of 4 weeks. Near-infrared fluorescent imaging of transplant recipients at 4 weeks demonstrated focal uptake of scVEGF/Cy in remodeling artery grafts. Uptake specificity was demonstrated using an inactive homolog of scVEGF/Cy. scVEGF/Cy uptake predominantly localized in the neointima of remodeling coronary arteries and correlated with VEGF receptor-1 but not VEGF receptor-2 expression. There was a significant correlation between scVEGF/Cy uptake and transplanted artery neointima area. Molecular imaging of VEGF receptors may provide a noninvasive tool for detection of graft arteriosclerosis in solid organ transplantation.

  1. Vascularized fibula grafts for reconstruction of bone defects after resection of bone sarcomas

    DEFF Research Database (Denmark)

    Petersen, Michael Mørk; Hovgaard, Dorrit; Elberg, Jens Jørgen

    2010-01-01

    We evaluated the results of limb-sparing surgery and reconstruction of bone defects with vascularized fibula grafts in 8 consecutive patients (mean age at operation 13.6 years (range 4.1-24.2 years), female/male = 6/2) with bone sarcomas (BS) (osteosarcoma/Ewing's sarcoma/chondrosarcoma= 4/3/1) o...... (n = 2), and hip dislocation (n = 1). Limb-sparing surgery with reconstruction of bone defects using vascularized fibular grafts in BS cases is feasible with acceptable clinical results, but fractures should be expected in many patients....

  2. Aspirin decreases platelet uptake on Dacron vascular grafts in baboons

    Energy Technology Data Exchange (ETDEWEB)

    Mackey, W.C.; Connolly, R.J.; Callow, A.D.; Keough, E.M.; Ramberg-Laskaris, K.; McCullough, J.L.; O' Donnell, T.F. Jr.; Melaragno, A.; Valeri, C.R.; Weiblen, B.

    1984-07-01

    The influence of a single dose of aspirin (5.4-7.4 mg/kg) on platelet uptake on 4-mm Dacron interposition grafts was studied in a baboon model using gamma camera scanning for 111-Indium labeled platelets. In vitro assessment of platelet function after aspirin administration revealed that in the baboon, as in the human, aspirin abolished arachidonic acid-induced platelet aggregation, prolonged the lag time between exposure to collagen and aggregation, and decreased plasma thromboxane B2 levels. Aspirin also prolonged the template bleeding time. Scans for 111-Indium labeled platelets revealed that pretreatment with a single dose of aspirin decreased platelet uptake on 4-mm Dacron carotid interposition grafts. This decrease in platelet uptake was associated with a significant improvement in 2-hour graft patency and with a trend toward improved 2-week patency.

  3. The in vivo performance of small-caliber nanofibrous polyurethane vascular grafts

    Directory of Open Access Journals (Sweden)

    Hu Zuo-jun

    2012-12-01

    Full Text Available Abstract Background In a previous in vitro study, we confirmed that small-caliber nanofibrous polyurethane (PU vascular grafts have favorable mechanical properties and biocompatibility. In the present study, we examined the in vivo biocompatibility and stability of these grafts. Methods Forty-eight adult male beagle dogs were randomly divided into two groups receiving, respectively, polyurethane (PU or polytetrafluoroethylene (PTFE grafts (n = 24 animals / group. Each group was studied at 4, 8, 12, and 24 weeks after graft implantation. Blood flow was analyzed by color Doppler ultrasound and computed tomography angiography. Patency rates were judged by animal survival rates. Coverage with endothelial and smooth muscle cells was characterized by hematoxylin-eosin and immunohistological staining, and scanning electron microscopy (SEM. Results Patency rates were significantly higher in the PU group (p = 0.02 vs. PTFE group. During the first 8 weeks, endothelial cells gradually formed a continuous layer on the internal surface of PU grafts, whereas coverage of PTFE graft by endothelial cells was inhomogeneous. After 12 weeks, neointimal thickness remained constant in the PU group, while PTFE group showed neointimal hyperplasia. At 24 weeks, some anastomotic sites of PTFE grafts became stenotic (p = 0.013 vs. PU group. Immunohistological staining revealed a continuous coverage by endothelial cells and an orderly arrangement of smooth muscle cells on PU grafts. Further, SEM showed smooth internal surfaces in PU grafts without thrombus or obvious neointimal hyperplasia. Conclusions Small-caliber nanofibrous PU vascular grafts facilitate the endothelialization process, prevent excessive neointimal hyperplasia, and improve patency rates.

  4. Fabrication and preliminary study of a biomimetic tri-layer tubular graft based on fibers and fiber yarns for vascular tissue engineering.

    Science.gov (United States)

    Wu, Tong; Zhang, Jialing; Wang, Yuanfei; Li, Dandan; Sun, Binbin; El-Hamshary, Hany; Yin, Meng; Mo, Xiumei

    2018-01-01

    Designing a biomimetic and functional tissue-engineered vascular graft has been urgently needed for repairing and regenerating defected vascular tissues. Utilizing a multi-layered vascular scaffold is commonly considered an effective way, because multi-layered scaffolds can easily simulate the structure and function of natural blood vessels. Herein, we developed a novel tri-layer tubular graft consisted of Poly(L-lactide-co-caprolactone)/collagen (PLCL/COL) fibers and Poly(lactide-co-glycolide)/silk fibroin (PLGA/SF) yarns via a three-step electrospinning method. The tri-layer vascular graft consisted of PLCL/COL aligned fibers in inner layer, PLGA/SF yarns in middle layer, and PLCL/COL random fibers in outer layer. Each layer possessed tensile mechanical strength and elongation, and the entire tubular structure provided tensile and compressive supports. Furthermore, the human umbilical vein endothelial cells (HUVECs) and smooth muscle cells (SMCs) proliferated well on the materials. Fluorescence staining images demonstrated that the axially aligned PLCL/COL fibers prearranged endothelium morphology in lumen and the circumferential oriented PLGA/SF yarns regulated SMCs organization along the single yarns. The outside PLCL/COL random fibers performed as the fixed layer to hold the entire tubular structure. The in vivo results showed that the tri-layer vascular graft supported cell infiltration, scaffold biodegradation and abundant collagen production after subcutaneous implantation for 10weeks, revealing the optimal biocompatibility and tissue regenerative capability of the tri-layer graft. Therefore, the specially designed tri-layer vascular graft will be beneficial to vascular reconstruction. Copyright © 2017. Published by Elsevier B.V.

  5. Autogenous tooth bone graft: Ingenious bone regeneration material

    Directory of Open Access Journals (Sweden)

    Chadalavada Sarala

    2018-01-01

    Full Text Available Tooth-derived bone graft material, which is proved to be rich in bone growth factors and bone morphogenic proteins (BMPs, have been becoming a practical substitute to bone grafting. It can also be used as a carrier for growth factors and stem cells as reported in many recent studies. Autogenous-tooth bone grafting technique is significant as this biomaterial has excellent bone regeneration capacity and also relatively non-existent chances of antigenicity, genetic diseases and disease transmission. In this article, a broad overview of the published findings with regard to the properties and uses of tooth-derived regenerative bone grafting is discussed.

  6. Modelling ultrasound-induced mild hyperthermia of hyperplasia in vascular grafts

    Directory of Open Access Journals (Sweden)

    Cheung Alfred K

    2011-11-01

    Full Text Available Abstract Background Expanded polytetrafluoroethylene (ePTFE vascular grafts frequently develop occlusive neointimal hyperplasia as a result of myofibroblast over-growth, leading to graft failure. ePTFE exhibits higher ultrasound attenuation than native soft tissues. We modelled the selective absorption of ultrasound by ePTFE, and explored the feasibility of preventing hyperplasia in ePTFE grafts by ultrasound heating. Specifically, we simulated the temperature profiles of implanted grafts and nearby soft tissues and blood under ultrasound exposure. The goal was to determine whether ultrasound exposure of an ePTFE graft can generate temperatures sufficient to prevent cell growth on the graft without damaging nearby soft tissues and blood. Methods Ultrasound beams from two transducers (1.5 and 3.2 MHz were simulated in two graft/tissue models, with and without an intra-graft cellular layer mimicking hyperplasia, using the finite-difference time-domain (FDTD method. The resulting power deposition patterns were used as a heat source for the Pennes bioheat equation in a COMSOL® Multiphysics heat transfer model. 50°C is known to cause cell death and therefore the transducer powers were adjusted to produce a 13°C temperature rise from 37°C in the ePTFE. Results Simulations showed that both the frequency of the transducers and the presence of hyperplasia significantly affect the power deposition patterns and subsequent temperature profiles on the grafts and nearby tissues. While neither transducer significantly raised the temperature of the blood, the 1.5-MHz transducer was less focused and heated larger volumes of the graft and nearby soft tissues than the 3.2-MHz transducer. The presence of hyperplasia had little effect on the blood's temperature, but further increased the temperature of the graft and nearby soft tissues in response to either transducer. Skin cooling and blood flow play a significant role in preventing overheating of the native

  7. Vascularized fibula grafts for reconstruction of bone defects after resection of bone sarcomas

    DEFF Research Database (Denmark)

    Petersen, Michael Mørk; Hovgaard, Dorrit; Elberg, Jens Jørgen

    2010-01-01

    We evaluated the results of limb-sparing surgery and reconstruction of bone defects with vascularized fibula grafts in 8 consecutive patients (mean age at operation 13.6 years (range 4.1-24.2 years), female/male = 6/2) with bone sarcomas (BS) (osteosarcoma/Ewing's sarcoma/chondrosarcoma= 4...

  8. Polyhydroxybutyrate/valerate/polycaprolactone small-diameter vascular graft: Experimental study of integration into organism

    Energy Technology Data Exchange (ETDEWEB)

    Antonova, L. V., E-mail: antonova.la@mail.ru; Burago, A. Yu.; Matveeva, V. G.; Velikanova, E. A.; Mukhamadiyarov, R. A.; Glushkova, T. V.; Kudryavtseva, Y. A.; Barbarash, O. L.; Barbarash, L. S. [Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo (Russian Federation); Mironov, A. V. [Kemerovo Cardiology Dispensary, Kemerovo (Russian Federation)

    2015-10-27

    We prepared polyhydroxybutyrate/valerate (PHBV)/polylcaprolactone (PCL) small-diameter vascular grafts using electrospinning. Surface structure was assessed by scanning electron microscopy whilst physicomechanical properties were investigated by longitudinal uniaxial tension testing. Patency of grafts implanted into the rat abdominal aorta was evaluated using a Doppler ultrasonography at 2 week, 1 month and 12 month postimplantation. In addition, we assessed local histological features, along with IL-1β, IL-2, IL-4, IL-10, TNFa, TGF-β1, and VEGF serum levels. We revealed that only 2 (25%) grafts were not thrombosed at 2 week and 1 month postimplantation. However, at 12 month postimplantation a satisfactory histological pattern was observed in 50% of all cases, and we detected a monolayer of endothelial cells on the inner graft surface in half the cases. Regarding other grafts, we revealed minor connective tissue hyperplasia in 41.7% of the grafts and an inflammatory infiltrate in the part of the arterial wall in 8.3% of the grafts. We found that the IL-1β serum level was 3.5-fold higher in the group of experimental rats at 12 month postimplantation (p < 0.01). In addition, the IL-2 and IL-4 serum levels at 12 month postimplantation were 2- and 2.8-fold higher as compared to short-term implantation (2 weeks and 1 month) and control rats (p < 0.05) whilst the IL-10 serum level at 1 and 12 month postimplantation was more than 100-fold higher in comparison with 2 week postimplantation and control rats (p < 0.001). Serum VEGF was detected only at 12 month postimplantation. All in all, we created a biocompatible PHBV/PCL small-diameter vascular graft with a high surface area to volume ratio. A long-term patency of biodegradable vascular grafts after implantation into the rat abdominal aorta and the absence of a considerable immune response confirmed a high biocompatibility of such construct and the possibility of its use as a vascular graft.

  9. Comparison of Temporary Open Arterial Revascularization Using Stent Grafts vs. Standard Vascular Shunts in a Porcine (Sus scrofa) Model

    Science.gov (United States)

    2017-01-24

    feasible strategy for damage control management of peripheral vascular injury and offers increased blood flow when compared to temporary shunts...survival model of porcine vascular injury . Methods: 12 Yorkshire-cross swine received a 2cm long near-circumferential defect in the iliac arteries. A14...shunts was greater than that of the stent grafts. Conclusion: Open sutureless direct site repair using stent grafts to treat vascular injury is a

  10. [ITI dental implants immediately placed into vascularized iliac bone grafts for reconstruction of mandibular defect: analysis of 12 consecutive cases].

    Science.gov (United States)

    Wu, Yi-qun; Zhang, Zhi-yong; Zhang, Zhi-yuan; Huang, Wei; Lai, Hong-chang; Hu, Yong-jie; Zhang, Chen-ping

    2005-04-01

    Vascularized iliac bone graft combined implantation has become a routine procedure in the functional reconstruction of mandibular defects. The aim of this study was to assess the clinical outcomes of the implants immediately placed into the vascularized iliac bone grafts. In this study, 12 consecutive patients with 36 ITI dental implants who had reconstruction of mandibular defect between 2000 and 2004 were presented. All implants were inserted immediately after bone grafting and loaded after 3 to 5 months of submerged healing. In general, a primary stability for implants placed in vascularized iliac bone grafts were achieved. After 1 year of observation the mean vertical bone loss was less than 1mm. There was no implant failure in the observation period. The vascularized iliac bone grafts are safe implant-bearing areas and allows a reliable and predictable restoration with dental implants. Implant-supported bridges and overdentures can be used in this procedure.

  11. Compliance Study of Endovascular Stent Grafts Incorporated with Polyester and Polyurethane Graft Materials in both Stented and Unstented Zones

    Directory of Open Access Journals (Sweden)

    Ying Guan

    2016-08-01

    Full Text Available Compliance mismatch between stent graft and host artery may induce complications and blood flow disorders. However, few studies have been reported on stent graft compliance. This study aims to explore the deformation and compliance of stent graft in stented and unstented zones under three pressure ranges. Compliance of two stent grafts incorporated with polyurethane graft (nitinol-PU and polyester graft (nitinol-PET materials respectively were tested; the stents used in the two stent grafts were identical. For the circumferential deformation of the stent grafts under each pressure range, the nitinol-PET stent graft was uniform in both zones. The nitinol-PU stent graft was circumferentially uniform in the stented zone, however, it was nonuniform in the unstented zone. The compliance of the PU graft material was 15 times higher than that of the PET graft. No significant difference in compliance was observed between stented and unstented zones of the nitinol-PET stent graft regardless of the applied pressure range. However, for the nitinol-PU stent graft, compliance of the unstented PU region was approximately twice that of the stented region; thus, compliance along the length of the nitinol-PU stent graft was not constant and different from that of the nitinol-PET stent graft.

  12. Mandibular Reconstruction Using the Free Vascularized Fibula Graft: An Overview of Different Modifications

    Directory of Open Access Journals (Sweden)

    George Kokosis

    2016-01-01

    Full Text Available The reconstruction of the mandible is a complex procedure because various cosmetic as well as functional challenges must be addressed, including mastication and oral competence. Many surgical techniques have been described to address these challenges, including non-vascularized bone grafts, vascularized bone grafts, and approaches related to tissue engineering. This review summarizes different modifications of the free vascularized fibula graft, which, since its introduction by Hidalgo in 1989, has become the first option for mandibular reconstruction. The fibula free flap can undergo various modifications according to the individual requirements of a particular reconstruction. Osteocutaneous flaps can be harvested for reconstruction of composite defects. 'Double-barreling' of the fibula can, for instance, enable enhanced aesthetic and functional results, as well as immediate one-stage osseointegrated dental implantation. Recently described preoperative virtual surgery planning to facilitate neomandible remodeling could guarantee good results. To conclude, the free fibula bone graft can currently be regarded as the "gold standard" for mandibular reconstruction in case of composite (inside and outside oral cavity defects as well as a way of enabling the performance of one-stage dental implantation.

  13. Tissue-Engineered Vascular Graft of Small Diameter Based on Electrospun Polylactide Microfibers

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    P. V. Popryadukhin

    2017-01-01

    Full Text Available Tubular vascular grafts 1.1 mm in diameter based on poly(L-lactide microfibers were obtained by electrospinning. X-ray diffraction and scanning electron microscopy data demonstrated that the samples treated at T=70°C for 1 h in the fixed state on a cylindrical mandrel possessed dense fibrous structure; their degree of crystallinity was approximately 44%. Strength and deformation stability of these samples were higher than those of the native blood vessels; thus, it was possible to use them in tissue engineering as bioresorbable vascular grafts. The experiments on including implantation into rat abdominal aorta demonstrated that the obtained vascular grafts did not cause pathological reactions in the rats; in four weeks, inner side of the grafts became completely covered with endothelial cells, and fibroblasts grew throughout the wall. After exposure for 12 weeks, resorption of PLLA fibers started, and this process was completed in 64 weeks. Resorbed synthetic fibers were replaced by collagen and fibroblasts. At that time, the blood vessel was formed; its neointima and neoadventitia were close to those of the native vessel in structure and composition.

  14. Fluid-dynamic optimal design of helical vascular graft for stenotic disturbed flow.

    Directory of Open Access Journals (Sweden)

    Hojin Ha

    Full Text Available Although a helical configuration of a prosthetic vascular graft appears to be clinically beneficial in suppressing thrombosis and intimal hyperplasia, an optimization of a helical design has yet to be achieved because of the lack of a detailed understanding on hemodynamic features in helical grafts and their fluid dynamic influences. In the present study, the swirling flow in a helical graft was hypothesized to have beneficial influences on a disturbed flow structure such as stenotic flow. The characteristics of swirling flows generated by helical tubes with various helical pitches and curvatures were investigated to prove the hypothesis. The fluid dynamic influences of these helical tubes on stenotic flow were quantitatively analysed by using a particle image velocimetry technique. Results showed that the swirling intensity and helicity of the swirling flow have a linear relation with a modified Germano number (Gn* of the helical pipe. In addition, the swirling flow generated a beneficial flow structure at the stenosis by reducing the size of the recirculation flow under steady and pulsatile flow conditions. Therefore, the beneficial effects of a helical graft on the flow field can be estimated by using the magnitude of Gn*. Finally, an optimized helical design with a maximum Gn* was suggested for the future design of a vascular graft.

  15. Fluid-dynamic optimal design of helical vascular graft for stenotic disturbed flow.

    Science.gov (United States)

    Ha, Hojin; Hwang, Dongha; Choi, Woo-Rak; Baek, Jehyun; Lee, Sang Joon

    2014-01-01

    Although a helical configuration of a prosthetic vascular graft appears to be clinically beneficial in suppressing thrombosis and intimal hyperplasia, an optimization of a helical design has yet to be achieved because of the lack of a detailed understanding on hemodynamic features in helical grafts and their fluid dynamic influences. In the present study, the swirling flow in a helical graft was hypothesized to have beneficial influences on a disturbed flow structure such as stenotic flow. The characteristics of swirling flows generated by helical tubes with various helical pitches and curvatures were investigated to prove the hypothesis. The fluid dynamic influences of these helical tubes on stenotic flow were quantitatively analysed by using a particle image velocimetry technique. Results showed that the swirling intensity and helicity of the swirling flow have a linear relation with a modified Germano number (Gn*) of the helical pipe. In addition, the swirling flow generated a beneficial flow structure at the stenosis by reducing the size of the recirculation flow under steady and pulsatile flow conditions. Therefore, the beneficial effects of a helical graft on the flow field can be estimated by using the magnitude of Gn*. Finally, an optimized helical design with a maximum Gn* was suggested for the future design of a vascular graft.

  16. Engineering vascularized bone grafts by integrating a biomimetic periosteum and β-TCP scaffold.

    Science.gov (United States)

    Kang, Yunqing; Ren, Liling; Yang, Yunzhi

    2014-06-25

    Treatment of large bone defects using synthetic scaffolds remain a challenge mainly due to insufficient vascularization. This study is to engineer a vascularized bone graft by integrating a vascularized biomimetic cell-sheet-engineered periosteum (CSEP) and a biodegradable macroporous beta-tricalcium phosphate (β-TCP) scaffold. We first cultured human mesenchymal stem cells (hMSCs) to form cell sheet and human umbilical vascular endothelial cells (HUVECs) were then seeded on the undifferentiated hMSCs sheet to form vascularized cell sheet for mimicking the fibrous layer of native periosteum. A mineralized hMSCs sheet was cultured to mimic the cambium layer of native periosteum. This mineralized hMSCs sheet was first wrapped onto a cylindrical β-TCP scaffold followed by wrapping the vascularized HUVEC/hMSC sheet, thus generating a biomimetic CSEP on the β-TCP scaffold. A nonperiosteum structural cell sheets-covered β-TCP and plain β-TCP were used as controls. In vitro studies indicate that the undifferentiated hMSCs sheet facilitated HUVECs to form rich capillary-like networks. In vivo studies indicate that the biomimetic CSEP enhanced angiogenesis and functional anastomosis between the in vitro preformed human capillary networks and the mouse host vasculature. MicroCT analysis and osteocalcin staining show that the biomimetic CSEP/β-TCP graft formed more bone matrix compared to the other groups. These results suggest that the CSEP that mimics the cellular components and spatial configuration of periosteum plays a critical role in vascularization and osteogenesis. Our studies suggest that a biomimetic periosteum-covered β-TCP graft is a promising approach for bone regeneration.

  17. Use of non-vascularized autologous fibula strut graft in the treatment of segmental bone loss.

    Science.gov (United States)

    Lawal, Y Z; Garba, E S; Ogirima, M O; Dahiru, I L; Maitama, M I; Abubakar, K; Ejagwulu, F S

    2011-01-01

    Fractures resulting in segmental bone loss challenge the orthopedic surgeon. Orthopedic surgeons in developed countries have the option of choosing vascularized bone transfers, bone transport, allogenic bone grafts, bone graft substitutes and several other means to treat such conditions. In developing countries where such facilities or expertise may not be readily available, the surgeon has to rely on other techniques of treatment. Non-vascularized fibula strut graft and cancellous bone grafting provides a reliable means of treating such conditions in developing countries. Over a period of six years all patients with segmental bone loss either from trauma or oncologic resection were included in the study. Data concerning the type of wound, size of gap and skin loss at tumor or fracture were obtained from clinical examination and radiographs. Ten patients satisfied the inclusion criteria for the study. The average length of the fibula strut is 7 cm, the longest being 15 cm and the shortest 3 cm long. The average defect length was 6.5 cm. Five patients had Gustillo III B open tibial fractures. One patient had recurrent giant cell tumor of the distal radius and another had a polyostotic bone cyst of the femur, which was later confirmed to be osteosarcoma. Another had non-union of distal tibial fracture with shortening. One other patient had gunshot injury to the femur and was initially managed by skeletal traction. The tenth patient had a comminuted femoral fracture. All trauma patients had measurement of missing segment, tissue envelope assessment, neurological examination, and debridement under general anesthesia with fracture stabilization with external fixators or casts. Graft incorporation was 80% in all treated patients. Autologous free, non-vascularized fibula and cancellous graft is a useful addition to the armamentarium of orthopedic surgeon in developing countries attempting to manage segmental bone loss, whether created by trauma or excision of tumors.

  18. Biomimetic modification of polyurethane-based nanofibrous vascular grafts: A promising approach towards stable endothelial lining.

    Science.gov (United States)

    Davoudi, Parivash; Assadpour, Shiva; Derakhshan, Mohammad Ali; Ai, Jafar; Solouk, Atefeh; Ghanbari, Hossein

    2017-11-01

    The emerging demand for small caliber vascular grafts to replace damaged vessels has attracted research attention. However, there is no perfect replacement in clinical use yet, mainly due to low patency rate of synthetic small caliber grafts. The main pathology behind low patency rate include thrombosis and graft/vessel hemodynamic mismatch, leading to intimal hyperplasia. Rapid in-situ endothelialization of vascular grafts is considered as one of the best strategies to overcome these complications. In the present study, Heparin and VEGF were immobilized via self-polymerization and deposition of polydopamine (PDA) on polyurethane (PU) nanofibrous scaffolds to improve endothelialization. Polyurethane nanofibrous scaffold (PUNF) that mimics vascular extracellular matrix (ECM) was chosen owing to its biocompatibility, biodegradability. Scanning electron microscopy (SEM), water contact angle (CA) measurement and Raman spectroscopy were used to characterize the surface, and tensile test was used to analyze mechanical properties before and after surface modification of the scaffolds. It was found that tensile strength and young's modulus were significantly increased after PDA coating on PUNF membranes. The hemocompatibility tests revealed that surface heparinization significantly inhibited the adhesion of platelet on the scaffolds. Immobilization of VEGF on the scaffolds significantly enhanced the proliferation of human umbilical vein endothelial cells (HUVECs) through enhanced cells adhesion and improved cell-scaffold interactions. The results suggest that dual-factor immobilization resulted in not only confluent monolayer of endothelial cells but also conferred excellent antithrombotic properties to the surface. This method of surface modification (immobilization of Heparin, VEGF by PDA layer) is suggested as a promising modification technique to increase hemocompatibility of small-diameter vascular grafts. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Effects of the placement of endosseous implants in vascularized bone grafts on bone union in beagle dogs.

    Science.gov (United States)

    Kobayashi, E; Ishihara, O; Mataga, I

    2005-09-01

    Recently, reconstructive surgery with revascularized osteocutaneous flaps has been used to restore function in patients with bone defects caused by surgery for oral cancer. However, few basic studies have addressed problems such as the union of bone segments after osteotomy, the effects of dental implant placement on blood flow, and bone formation at the bone:implant interface in grafted bone. Nine adult beagle dogs were divided into three groups of three dogs each. Each group received osteotomized vascularized tibial grafts, osteotomized tibial grafts with implants (implants placed in contralateral limbs as control), or simple (non-vascularized) tibial grafts. The development of bone around the implants was studied by histological examination, contact micro-radiography (CMR), and fluorescent bone labeling. In the dogs receiving osteotomized vascularized tibial grafts, bone bridging was confirmed at both the medial and distal junctions of the bone segments after 4 weeks. Additional newly formed bone was observed after 8 weeks, and bone union at the surface of the segments was completed after 12 weeks. In contrast, bone formation was clearly delayed in dogs receiving simple (non-vascularized) tibial grafts. Histologically, no difference in bone union was evident between limbs with dental implants in tibial bone and control limbs without implants, suggesting that implant placement does not negatively affect revascularization. Fluorescent bone labeling technique confirmed high vascularity of the vascularized tibial bone grafts but not of the simple (non-vascularized) tibial bone grafts early after the procedure. Our results suggest that osseointegration occurred around dental implants placed at the same time as reconstruction with osteotomized vascularized bone grafts in this animal model.

  20. Coagulation-induced resistance to fluid flow in small-diameter vascular grafts and graft mimics measured by purging pressure.

    Science.gov (United States)

    Nichols, Michael D; Choudhary, Rewa; Kodali, Santhisri; Reichert, William M

    2013-11-01

    In this study, the coagulation-induced resistance to flow in small-diameter nonpermeable Tygon tubes and permeable expanded polytetrafluoroethylene (ePTFE) vascular grafts was characterized by measuring the upstream pressure needed to purge the coagulum from the tube lumen. This purging pressure was monitored using a closed system that compressed the contents of the tubes at a constant rate. The pressure system was validated using a glycerin series with well-defined viscosities and precisely controlled reductions in cross-sectional area available for flow. This system was then used to systematically probe the upstream pressure buildup as fibrin glue, platelet-rich plasma (PRP) or whole blood coagulated in small-diameter Tygon tubing and or ePTFE grafts. The maximum purging pressures rose with increased clot maturity for fibrin glue, PRP, and whole blood in both Tygon and ePTFE tubes. Although the rapidly coagulating fibrin glue in nonpermeable Tygon tubing yielded highly consistent purging curves, the significantly longer and more variable clotting times of PRP and whole blood, and the porosity of ePTFE grafts, significantly diminished the consistency of the purging curves. Copyright © 2013 Wiley Periodicals, Inc.

  1. Dental Hetero-Graft Materials with Nano Hydroxyapatite Surface Treatment.

    Science.gov (United States)

    Kim, Dai-Hwan; Kim, Kyung-Il; Yoon, Seokyoung; Kim, Hyung-Jo; Ahn, Jin-Soo; Jun, Sang Ho; Kang, Ho Chang; Pang, Changhyun; Kim, Jaeyun; Cha, Hyung Joon; Han, Kwon-Hoon; Kim, Dong-Myong; Lee, Jung Heon

    2015-10-01

    We report the development of hydroxyapatite nanoparticle (HAp NP)-functionalized hetero-graft materials (HGMs) for dental applications. These HGMs were prepared by attaching platelet-, needle-, and sphere-shaped HAp NPs to the surface of xenograft materials through chemical conjugation. Although all three HAp NPs contributed to increase the surface area of bone graft material (BGM), the shape of the HAp NPs was a determining factor. Platelet HAp NPs were most effective, because they caused a 48.9% increase in BGM surface area whereas the influence of the spherical NP was only a 6.7% increase. This suggests that geometric factors regarding both the attached HAp NPs and graft material surface are essential in controlling the surface roughness of graft materials. Among the three HAp NPs, it was the platelet HAp NPs that helped to increase the efficacy of the BGM most significantly. Compared with BGM with no HAp NP attachment, HGM with platelet HAp NP ('platelet-HGM) treatment had ~46.1% higher cell attachment and proliferation rate. The MTT assay also showed that the HAp NP-treated hetero-graft materials had negligible cytotoxicity.

  2. Non-invasive monitoring of vascularization of grafted engineered human oral mucosa

    Science.gov (United States)

    Wolf, D. E.; Seetamraju, M.; Gurjar, R. S.; Kuo, R. S.; Fasi, A.; Feinberg, S. E.

    2012-03-01

    Accident victims and victims of explosive devices often suffer from complex maxillofacial injuries. The lips are one of the most difficult areas of the face to reconstruct after an avulsion. Lip avulsion results in compromised facial esthetics and functions of speech and mastication. The process of reconstruction requires assessment of the vascularization of grafted ex vivo engineered tissue while it is buried underneath the skin. We describe the design and animal testing of a hand-held surgical probe based upon diffuse correlation spectroscopy to assess vascularization.

  3. Intra-graft injection of tacrolimus promotes survival of vascularized composite allotransplantation.

    Science.gov (United States)

    Olariu, Radu; Denoyelle, Julie; Leclère, Franck M; Dzhonova, Dzhuliya V; Gajanayake, Thusitha; Banz, Yara; Hayoz, Michael; Constantinescu, Mihai; Rieben, Robert; Vögelin, Esther; Taddeo, Adriano

    2017-10-01

    Immunosuppressive therapies derived from solid organ transplantation are effective in promoting survival of vascularized composite allotransplantation (VCA), but they cause serious side effects that are difficult to justify for this non-life-saving procedure. Unlike solid organ transplantation, hand and face transplants offer the possibility of site-specific immunosuppression for reducing systemic exposure while increasing intra-graft concentrations of the drug. Therefore, in this study, we tested whether a single intra-graft injection tacrolimus could promote VCA survival. Brown Norway-to-Lewis hind limb transplantations were performed, and animals were left untreated (group I), treated with a daily injection of 1-mg/kg tacrolimus for 21 days (group 2) or injected with 7-mg tacrolimus directly into the transplanted limb on day 1 (group III). Graft rejection was monitored, and animals were sacrificed at grade 3 rejection or 200 days after transplantation. Intra-graft injection of tacrolimus significantly prolonged allograft survival as compared to untreated animals or animals treated with systemic tacrolimus. Half of the intra-graft-treated rats rejected their graft on average at day 70.5. Interestingly, the other half remained rejection-free for more than 200 days without signs of kidney or liver toxicity. In these animals, tacrolimus was detected in the VCA skin but not in the blood until day 200. Long-term survival was not linked to induction of donor-specific tolerance but to a higher level of lymphocyte chimerism. Intra-graft delivery of tacrolimus may promote VCA survival by increasing tissue drug availability and promoting the establishment of transient chimerism and thus long-term graft acceptance. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Gelatine and gelatine/elastin nanocomposites for vascular grafts: processing and characterization.

    OpenAIRE

    Lamprou, D; Zhdan, P; Labeed, F; Lekakou, C.

    2011-01-01

    This study involves the preparation, microstructural, physical, mechanical, and biological characterization of novel gelatine and gelatine/elastin gels for their use in the tissue engineering of vascular grafts. Gelatine and gelatine/elastin nanocomposite gels were prepared via a sol-gel process, using soluble gelatine. Gelatine was subsequently cross-linked by leaving the gels in 1% glutaraldehyde. The cross-linking time was optimized by assessing the mass loss of the cross-linked gels in wa...

  5. Mechanical analysis of the vascularized fibular graft prosthetic composite (VFGPC) for internal hemipelvectomy reconstruction.

    Science.gov (United States)

    Morris, Jonathan; Yang, Rui; Roth, Michael; Gill, Jonathan; Gorlick, Richard; Lo, Yungtai; Hoang, Bang H; Garfein, Evan; Geller, David S

    2017-06-01

    The vascularized fibular graft prosthetic composite (VFGPC) is used for reconstruction after internal hemipelvectomy. The purpose of this study was to create a mathematical model that calculates the mechanical effects of the vascularized fibular graft on the VFGPC. The effects of the VFG positioning were calculated based on three-dimensional static analyzes to determine the direction, magnitude, and distribution of the forces through the prosthesis and VFG. The shear stress (SS) and cyclic loads to failure (CLF) were calculated. By varying the location of the VFG on the sacrum the zone of acceptable placement was calculated. Utilization of the VFG decreased the forces through the implant by 15-35% and decreased SS 20-54%, depending on stance. The CLF improved by 94%. The zone of acceptable placement for the VFG was found to be between 0° and 15° of the vertical axis in the sagittal plane and 0° and 30° of the posterior axis in coronal plane. Determining the position of the VFG pre-operatively allows for the creation of a customized cutting jig can be utilized to create graft allowing for accurate fibular osteotomies, minimization of ischemia time, and decreased intra-operative handling of the graft. © 2017 Wiley Periodicals, Inc.

  6. Aneurysmal angiosarcoma associated with vascular graft revealed by 18F-FDG-PET imaging

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    Ahmed Chetouani, MD

    2017-06-01

    Full Text Available We report a rare case of vascular graft-associated aneurysmal angiosarcoma by 18F-Fluorodeoxyglucose (FDG positron emission tomography (PET. An 81-year-old male patient, with a prior history of graft interposition 1 year previously, was referred to 18F-FDG-PET because of an inflammatory syndrome of unknown origin. FDG-PET images revealed a particular pattern of intense circular uptake within the arterial wall (SUVmax = 10 in a popliteal aneurysm and, additionally, a large hypermetabolic mass centered by the graft. Remote hypermetabolisms in lung nodules and pleural thickenings were also detected. The diagnosis of angiosarcoma was ascertained through histopathological analysis of surgical samples. Development of an aneurysmal angiosarcoma at the site of a vascular graft is a rare entity, often misdiagnosed. 18F-FDG-PET appears to be useful in its detection with a PET pattern of intense circular uptake within the arterial wall. Such finding should lead to the search for distant metastasis.

  7. Vascularization after treatment of gingival recession defects with platelet-rich fibrin or connective tissue graft.

    Science.gov (United States)

    Eren, Gülnihal; Kantarcı, Alpdoğan; Sculean, Anton; Atilla, Gül

    2016-11-01

    The aim of this study was to evaluate histologically the following treatment of bilateral localized gingival recessions with coronally advanced flap (CAF) combined with platelet-rich fibrin (PRF) or subepithelial connective tissue graft (SCTG). Tissue samples were harvested from 14 subjects either 1 or 6 months after the surgeries. The 2-mm punch biopsies were obtained from the mid-portion of the grafted sites. Neutral buffered formalin fixed, paraffin-embedded 5-μm thick tissue sections were stained with hematoxylin eosin and Masson's trichrome in order to analyze the collagen framework, epithelium thickness and rete-peg length. Multiple sequential sections were cut from paraffin-embedded blocks of tissue and immunohistochemically prepared for detection of vascular endothelial growth factor, CD31 and CD34, for the assessment of vascularization. Rete peg formation was significantly increased in the sites treated with PRF compared to the SCTG group after 6 months (p tissue maturation compared to connective tissue graft. PRF regulated the vascular response associated with an earlier wound healing.

  8. Automation of a test bench for accessing the bendability of electrospun vascular grafts

    Directory of Open Access Journals (Sweden)

    Bensch Martin

    2016-09-01

    Full Text Available One of the greatest challenges in cardiovascular tissue engineering is to develop vascular grafts with properties similar to autologous vessels. A promising approach is the fabrication of scaffolds from biodegradable polymers by electrospinning. Unstructured vascular subs possess a weak dimensional stability resulting in lumen collapse when subjected to bending stress. In order to examine different structured grafts, a standardised test method is required. A manual test method, designed in a former study, was adopted in terms of standardisation and automation. Therefore, a control system was programmed to regulate the required electronics. The electronic circuit was then developed and put into service. To fix samples into the test bench a new sample holder and a new collector for electrospinning were designed. Subsequently, a validation showed the new systems’ improved functionality compared to the former test bench. The samples were manufactured with the new collector. They could be fixed to the sample holder with high repeatability. The demand for vascular grafts with biological and mechanical properties similar to autologous vessels requires a standardised test method to examine bendability. The new test system enables the scaffolds to be examined regarding bendability with low personal expense and a simultaneously high degree of reproducibility. In addition, the new collector geometry can be easily adapted to higher or lower inner diameters. Hence, a new sample geometry was developed within this work.

  9. Is There Benefit to Free Over Pedicled Vascularized Grafts in Augmenting Tibial Intercalary Allograft Constructs?

    Science.gov (United States)

    Manfrini, Marco; Bindiganavile, Srimanth; Say, Ferhat; Colangeli, Marco; Campanacci, Laura; Depaolis, Massimiliano; Ceruso, Massimo; Donati, Davide

    2017-05-01

    Intercalary reconstruction of tibial sarcomas with vascularized fibula autografts and massive bone allografts is reliable with predictable long-term results. However, inadequate data exist comparing free and pedicled vascularized fibula autografts in combination with a massive bone allograft in patients undergoing intercalary tibia reconstructions. Among patients undergoing large-segment intercalary allografting, we sought to compare supplemental free vascularized fibular autografts with supplemental pedicled vascularized fibular autografts, in terms of (1) oncologic results, (2) complications associated with surgery, (3) Musculoskeletal Tumor Society (MSTS) scores, and (4) surgical time. Between 1994 and 2013, we treated 320 patients, younger than 40 years, with tibial sarcomas. Thirty-five patients (11%) underwent amputations. One hundred ninety-five patients (61%) were treated with intraarticular resection of the tibia, which constituted 104 tumor endoprostheses, 63 proximal tibia allograft prosthetic composites, 21 osteoarticular allografts, and seven arthrodeses with allografts. Ninety patients (28%) underwent joint-sparing intercalary reconstruction. Forty-one (13%) of these 90 patients were treated with allografts alone, two (1%) with vascularized fibula grafts, and 47 (15%) with intercalary allografts supplemented by autografts (free fibular autografts, 22 patients, 7%; pedicled fibular autografts, 25 patients, 8%). During the study period, we used free vascularized fibular autografts in association with massive bone allograft for a resection longer than 12 cm with a very small periarticular residual segment. The choice for using a pedicled fibula harvested in the ipsilateral leg initially was for patients having only diaphyseal resections and the indication was later extended to intraepiphyseal osteotomies with a small periarticular residual segment. The goals of this study are to present the long-term results in this group of patients and compare their

  10. Vascular graft thrombosis secondary to activated protein C resistance: a case report and literature review.

    Science.gov (United States)

    Pejkic, Sinisa; Savic, Nebojsa; Paripovic, Miroslav; Sladojevic, Milos; Doric, Predrag; Ilic, Nikola

    2014-02-01

    Hypercoagulability is a well-documented and prominent risk factor for venous thromboembolism. The role of thrombophilia in arterial thrombotic events is less well defined. A 52-year-old male patient with multiple atherogenic risk factors was admitted for non-healing pedal ulcer and absent distal pulses. Based on the clinical presentation, Doppler ultrasound and angiography findings, the patient underwent elective in situ bypass arterial reconstruction. The saphenous vein graft was of satisfactory quality and the procedure went routinely. Acute graft thrombosis on postoperative day 0 was recognized immediately and prompted an emergent surgical revision. No technical errors or anatomical/mechanical causes for failed reconstruction were found and the graft was successfully thrombectomized using a Fogarty balloon-catheter. Graft rethrombosis, however, ensued after several hours. Considering the absence of threatening limb ischemia and the idiopathic recurrent thrombosis, raising suspicion of prothrombotic state, conservative treatment was pursued. Postoperative thrombophilia testing proved positive for activated protein C resistance, mandating introduction of chronic oral anticoagulation. Six months later, the operated extremity is viable. Inexplicable vascular graft thrombosis, particularly if early and recurrent, should raise suspicion of underlying thrombophilia. If confirmed by laboratory testing, long-term secondary antithrombotic prophylaxis may be required.

  11. Vascularized scapular grafting for treatment of osteonecrosis of the humeral head.

    Science.gov (United States)

    Kawamura, Kenji; Kawate, Kenji; Yajima, Hiroshi; Kobata, Yasunori; Takakura, Yoshinori

    2008-11-01

    Eight dissections in four embalmed cadavers were performed to investigate the possibility of vascularized scapular grafting for osteonecrosis of the humeral head. When the angular branch was used as the nutrient vessel, the mean length of the vascular pedicle was 12.4 cm, which was sufficient for transferring the scapula into the humeral head. Based on the anatomical study, a 27-year-old man with corticosteroid-induced osteonecrosis of the right humeral head was treated by vascularized scapular grafting. The pedicled vascularized scapula was successfully transferred into the humeral head using the angular branch. The patient's right shoulder pain disappeared following surgical recovery. He had no limitations of right shoulder motion 3 years after the surgery. Magnetic resonance imaging at 1 year after the surgery indicated revascularization of the humeral head. The humeral head did not collapse during a 3-year follow-up with radiographic evaluation. This procedure has the potential to be a new joint-preserving procedure for osteonecrosis of the humeral head.

  12. Cost-Utility Analysis: Sartorius Flap versus Negative Pressure Therapy for Infected Vascular Groin Graft Managment

    Science.gov (United States)

    Macarios, David; Griffin, Leah; Kosowski, Tomasz; Pyfer, Bryan J.; Offodile, Anaeze C.; Driscoll, Daniel; Maddali, Sirish; Attwood, John

    2015-01-01

    Background: Sartorius flap coverage and adjunctive negative pressure wound therapy (NPWT) have been described in managing infected vascular groin grafts with varying cost and clinical success. We performed a cost–utility analysis comparing sartorius flap with NPWT in managing an infected vascular groin graft. Methods: A literature review compiling outcomes for sartorius flap and NPWT interventions was conducted from peer-reviewed journals in MEDLINE (PubMed) and EMBASE. Utility scores were derived from expert opinion and used to estimate quality-adjusted life years (QALYs). Medicare current procedure terminology and diagnosis-related groups codes were used to assess the costs for successful graft salvage with the associated complications. Incremental cost-effectiveness was assessed at $50,000/QALY, and both univariate and probabilistic sensitivity analyses were conducted to assess robustness of the conclusions. Results: Thirty-two studies were used pooling 384 patients (234 sartorius flaps and 150 NPWT). NPWT had better clinical outcomes (86.7% success rate, 0.9% minor complication rate, and 13.3% major complication rate) than sartorius flap (81.6% success rate, 8.0% minor complication rate, and 18.4% major complication rate). NPWT was less costly ($12,366 versus $23,516) and slightly more effective (12.06 QALY versus 12.05 QALY) compared with sartorius flap. Sensitivity analyses confirmed the robustness of the base case findings; NPWT was either cost-effective at $50,000/QALY or dominated sartorius flap in 81.6% of all probabilistic sensitivity analyses. Conclusion: In our cost–utility analysis, use of adjunctive NPWT, along with debridement and antibiotic treatment, for managing infected vascular groin graft wounds was found to be a more cost-effective option when compared with sartorius flaps. PMID:26893991

  13. Engineering and Applications of DNA-Grafting Polymer Materials.

    Science.gov (United States)

    Peng, Lu; Wu, Cuichen; You, Mingxu; Han, Da; Chen, Yan; Fu, Ting; Ye, Mao; Tan, Weihong

    2013-05-01

    The emergence of hybrid materials combining biomacromolecules and organic polymers has received broad attention based on their potential applications in chemical, biological and materials sciences. Among different coupling strategies, the grafting of oligonucleotides to organic polymers as side chains by covalent bonds provides a novel platform whereby the properties of both oligonucleotides and polymer backbone are integrated, manipulated and optimized for various applications. In this review, we give the perspective on this specific type of DNA polymer hybrid materials , using selected examples with emphasis on bioanalysis, biomedicine and stimuli-responsive materials. It is expected the success of DNA-grafting polymers will not only impact the frabication of novel bimolecule incorporated materials, but also will influence how the properties of synthetic materials are tailored using different functional groups.

  14. Vastus lateralis vascularized nerve graft in facial nerve reconstruction: an anatomical cadaveric study and clinical implications.

    Science.gov (United States)

    Agrogiannis, Nikolaos; Rozen, Shai; Reddy, Gangadasu; Audolfsson, Thorir; Rodriguez-Lorenzo, Andres

    2015-02-01

    The present study investigates the vascular anatomy of the vastus lateralis motor nerve (VLMN) to be used as a vascularized nerve graft in facial nerve reconstruction. We evaluated the maximum length of the nerve that can be included in the flap and its vascular pedicle. In addition, we discuss its adequacy for use in early reconstruction of the facial nerve both as ipsilateral facial nerve reconstruction and as cross-facial nerve graft. Five fresh cadavers were used in this study. In all specimens, the VLMN and its vascular pedicle were dissected, photodocumented and measured using calipers. In addition, two vascularized VLMN were injected with a radiopaque contrast and underwent CT angiography and three dimensional reconstructions were scanned to illustrate the vascular supply of the nerve using OsiriX Software. The VLMN was divided into two divisions, an oblique proximal and a descending distal, in 70% of the dissections with a mean maximal length of 8.4 ± 4.5 cm for the oblique division and 15.03 ± 3.87 cm for the descending division. The length of the oblique division, when present, was shorter than the length of the descending branch in all specimens. The mean length of the pedicle was 2.93 ± 1.69 cm, and 3.27 ± 1.49 cm until crossing the oblique and the descending division of the nerve respectively. The mean caliber of the nerve was 2.4 ± 0.62 mm. Three-dimensional computed tomography angiography demonstrated perfusion throughout the entire VLMN by branches from the descending branch of the lateral femoral circumflex artery which ran parallel to the descending division of the VLMN. Additionally, we observed that technically it was possible to preserve the oblique branch of the VLMN. This study confirms that VLMN presents adequate anatomic features to be used as a vascularized nerve graft for facial nerve reconstruction in terms of length, pedicle, and caliber. © 2014 Wiley Periodicals, Inc.

  15. Reconstruction of Mandibular Defect by Free Re-Vascularized Fibula Graft: A Case Report

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    Quazi Billur Rahman

    2009-11-01

    Full Text Available Background: In maxillofacial surgery tumor ablation often causes continuity defect of mandible which results anatomical and functional morbidity of the patient. The reconstruction of the mandibular defect is mandatory to restore the oral function and speech. Various methods of immediate reconstruction are implemented by different authors time to time including autogenous non vascularized bone graft, allogenic bone graft , auto frozen mandible or reconstruction plates and others. Each has its own advantages and disadvantages including donor site morbidity, failure and others. The purpose of the present case report is to establish micorvascular free fiblula is as a better option to other methods in immediate reconstruction of mandibular continuity defect. Objective: Anatomical, functional and esthetic rehabilitation of patients after mandibular resection Method: Revascularization of free fibula graft by microvascular anastomosis of paroneal artery with facial artery at the segmental defect site of mandible. Result: Remarkable contour, cosmesis and early functional rehabilatation of the patient. Conclusion: Microvascular reconstruction with fibula is the better option for defect correction and early rehabilitation in patients with mandibular continuity defect. Key words: Mandible, defect; reconstruction; microvascular technique; fibula graftDOI: 10.3329/bsmmuj.v1i1.3698 BSMMU J 2008; 1(1: 35-38

  16. Osteoinduction of bone grafting materials for bone repair and regeneration.

    Science.gov (United States)

    García-Gareta, Elena; Coathup, Melanie J; Blunn, Gordon W

    2015-12-01

    Regeneration of bone defects caused by trauma, infection, tumours or inherent genetic disorders is a clinical challenge that usually necessitates bone grafting materials. Autologous bone or autograft is still considered the clinical "gold standard" and the most effective method for bone regeneration. However, limited bone supply and donor site morbidity are the most important disadvantages of autografting. Improved biomaterials are needed to match the performance of autograft as this is still superior to that of synthetic bone grafts. Osteoinductive materials would be the perfect candidates for achieving this task. The aim of this article is to review the different groups of bone substitutes in terms of their most recently reported osteoinductive properties. The different factors influencing osteoinductivity by biomaterials as well as the mechanisms behind this phenomenon are also presented, showing that it is very limited compared to osteoinductivity shown by bone morphogenetic proteins (BMPs). Therefore, a new term to describe osteoinductivity by biomaterials is proposed. Different strategies for adding osteoinductivity (BMPs, stem cells) to bone substitutes are also discussed. The overall objective of this paper is to gather the current knowledge on osteoinductivity of bone grafting materials for the effective development of new graft substitutes that enhance bone regeneration. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Development of Non-Cell Adhesive Vascular Grafts Using Supramolecular Building Blocks

    NARCIS (Netherlands)

    van Almen, Geert C.; Talacua, Hanna; Ippel, Bastiaan D.; Mollet, Björne B.; Ramaekers, Mellany; Simonet, Marc; Smits, Anthal I. P. M.; Bouten, Carlijn V. C.; Kluin, Jolanda; Dankers, Patricia Y. W.

    2016-01-01

    Cell-free approaches to in situ tissue engineering require materials that are mechanically stable and are able to control cell-adhesive behavior upon implantation. Here, the development of mechanically stable grafts with non-cell adhesive properties via a mix-and-match approach using

  18. Prospective analysis of Hemodialysis Reliable Outflow (HeRO) vascular access graft vs. cuffed catheter access in hemodialysis.

    Science.gov (United States)

    Provenzano, Robert; LaFleur, Paula; McFadden, Lori; LaFleur, Matthew; Lorelli, David

    2015-11-01

    The Hemodialysis Reliable Outflow (HeRO) graft was compared to the cuffed catheter in end-stage renal disease patients. All consented patients were evaluated for HeRO graft placement. Eligible patients that did not receive a graft were enrolled in the control group. Participants who had not exhausted peripheral venous access sites suitable for fistulas and grafts were excluded. Differences in quality of life and incidence of bacteremia, vascular interventions, hospitalizations, and death were evaluated over one year. In thirty-three patients included in the analysis--16 HeRO, 17 control--significantly fewer bacteremia events (93.8% vs. 64.7%) and a significantly increased number of vascular interventions (64.7% vs. 25%) were reported for the HeRO versus Control group. The increased interventions in the HeRO group may be due to the two-step placement process.

  19. Small-diameter tissue engineered vascular graft made of electrospun PCL/lecithin blend.

    Science.gov (United States)

    Zhang, Min; Wang, Kai; Wang, Zhexiang; Xing, Bin; Zhao, Qiang; Kong, Deling

    2012-11-01

    In this study, natural lecithin was incorporated into cholesterol-poly(ε-caprolactone) (Chol-PCL) by solution blending in order to modify the performance of the hydrophobic and bio-inert PCL. The fibrous Chol-PCL/lecithin membranes were fabricated by electrospinning, and the surface morphology and properties were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, static water contact angle, and mechanical tensile testing. The blood compatibility of the scaffolds was evaluated by in vitro hemolysis assay. The cytocompatibility of the scaffolds was investigated by cell adhesion and proliferation using bone-marrow mesenchymal stem cells (MSCs). Subcutaneous implantation was also performed to evaluate the in vivo inflammatory reaction. The tubular tissue-engineered vascular graft (TEVG) was further constructed by rolling cell sheet comprising fibrous membrane and MSCs. Furthermore, endothelial cells (ECs) were seeded onto the lumen of the graft with the aim to form vascular endothelium. The preliminary results indicate that electrospun Chol-PCL/lecithin scaffolds show improved hemocompatibility and cytocompatibility compared with neat Chol-PCL, and combining the Chol-PCL/lecithin fibrous scaffold with MSCs and ECs with well controlled distribution is a promising strategy for constructing TEVGs.

  20. Limb-saving surgery by intraoperative radiation and vascularized fibular graft for osteosarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Osamu; Arakaki, Akira; Asato, Jun; Shimabukuro, Hiroyuki; Shingaki, Yoshisada; Asato, Hideki; Ibaraki, Kunio; Nakano, Masao (University of the Ryukyus, Okinawa (Japan))

    1992-03-01

    Various limb-saving surgeries for osteosarcomas have been performed owing to the high survival rate achieved by chemotherapy. However, reconstruction by endoprosthesis after radical resection of the tumor in the distal femur or proximal tibia was often complicated by early or late severe problems. The radicality of intraoperative radiation by Lineac 50 Gy for osteosarcoma has been proved clinically by Yamamuro et al, while radiation therapy often ensued pathological fractures. Therefore, for osteosarcomas in four distal femurs and one proximal tibia, we have adopted a vascularized fibular graft to reinforce the irradiated bone and to prevent the collapse of the joint surface. Resected osseous parts were irradiated in four cases with resultant infections in two cases. Intraoperative irradiation without resection was performed on one case with an uneventful short course. Although the ranges of motion in three survivous were limited, the prospect of limb-saving surgery by intraoperative irradiation and incorporated vascularized fibular grafts seem favorable as they promise longer durability. (author).

  1. The effects of vasoactive agents on flow through saphenous vein grafts during lower-extremity peripheral vascular surgery.

    Science.gov (United States)

    Maslow, Andrew D; Bert, Arthur; Slaiby, Jeffrey; Carney, William; Marcaccio, Edward

    2007-06-01

    The purpose of this study was to assess the effects of hemodynamic alterations on vein graft flow during peripheral vascular surgery. It was hypothesized that vasopressors can be administered without compromising flow through the vein grafts. Tertiary care center, university medical center. Randomized placebo-controlled double-blinded study. The effects of phenylephrine, epinephrine, milrinone, intravenous fluid, and placebo on newly constructed peripheral vein grafts were assessed in 60 patients (12 patients in each of 5 groups). Systemic and central hemodynamics were measured by using intra-arterial and pulmonary artery catheters. Vein graft flow was measured by using a transultrasonic flow probe (Transultrasonic Inc, Ithaca, NY). Phenylephrine increased systemic mean blood pressure (mBP) (68.2-94.0 mmHg, p < 0.01), systemic vascular resistance (SVR) (1,091-1,696 dynes x sec x cm(-5), p < 0.001), and vein graft flow (39.5-58.9 mL/min, p < 0.01), whereas cardiac output remained unchanged. Epinephrine resulted in increased cardiac output (4.4-6.9 L/min, p < 0.01) and mBP (72.7-89.1 mmHg, p < 0.01), whereas vein graft flow was reduced in 6 of 12 patients. Intravenous fluid administration resulted in a relatively smaller increase in graft flow (37.6-46.0 mL/min, p < 0.05), an increase in cardiac output, and an insignificant decrease in SVR. Other treatments had either little or no effect on vein graft flow. The study hypothesis was partly supported. Although both phenylephrine and epinephrine increased blood pressure, only the former increased vein graft flow in all patients. In conjunction with increases in graft flow after fluid administration, these data suggest that factors affecting vein graft flow are not just simply related to systemic hemodynamics.

  2. Indications for free vascularized fibular grafting for the treatment of osteonecrosis of the femoral head

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    Kawamura Kenji

    2007-08-01

    Full Text Available Abstract Background The present study aimed to determine the indications for free vascularized fibular grafting for the treatment of osteonecrosis of the femoral head. Methods Seventy-one hips (60 patients were clinically followed for a minimum of 3 years. Average follow-up period was 7 years. Etiologies were alcohol abuse in 31 hips, steroid use in 27, idiopathic in 7 and trauma in 6. Preoperative staging of the necrotic lesion was done using the Steinberg's classification system. The outcomes of free vascularized fibular grafting were determined clinically using the Harris hip-scoring system, radiographically by determining progression, and survivorship by lack of conversion to total hip replacement. Results The average preoperative Harris hip score was 56 points and the average score at the latest follow-up examination was 78 points. Forty-seven hips (67% were clinically rated good to excellent, 4 hips (6% were rated fair, and 20 hips (28% were rated poor. Thirty-six hips (51% did not show radiographic progression while 35 hips (49% did, and with an overall survivorship of 83% at 7 years. Steroid-induced osteonecrosis was significantly associated with poor scores and survival rate (68%. Preoperative collapse was significantly associated with poor scores, radiographic progression and poor survival rate (72%. A large extent of osteonecrosis greater than 300 degrees was significantly associated with poor scores, radiographic progression and poor survival rate (67%. There was no relationship between the distance from the tip of the grafted fibula to the subchondral bone of the femoral head and postoperative radiographic progression. Conclusion In conclusion, small osteonecrosis (less than 300 degrees of the femoral head without preoperative collapse (Steinberg's stages I and II is the major indication for free vascularized fibular grafting. Steroid-induced osteonecrosis is a relative contraindication. Large osteonecrosis (greater than 300 degrees

  3. Conjugation with RGD Peptides and Incorporation of Vascular Endothelial Growth Factor Are Equally Efficient for Biofunctionalization of Tissue-Engineered Vascular Grafts

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    Larisa V. Antonova

    2016-11-01

    Full Text Available The blend of poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV and poly(ε-caprolactone (PCL has recently been considered promising for vascular tissue engineering. However, it was shown that PHBV/PCL grafts require biofunctionalization to achieve high primary patency rate. Here we compared immobilization of arginine–glycine–aspartic acid (RGD-containing peptides and the incorporation of vascular endothelial growth factor (VEGF as two widely established biofunctionalization approaches. Electrospun PHBV/PCL small-diameter grafts with either RGD peptides or VEGF, as well as unmodified grafts were implanted into rat abdominal aortas for 1, 3, 6, and 12 months following histological and immunofluorescence assessment. We detected CD31+/CD34+/vWF+ cells 1 and 3 months postimplantation at the luminal surface of PHBV/PCL/RGD and PHBV/PCL/VEGF, but not in unmodified grafts, with the further observation of CD31+CD34−vWF+ phenotype. These cells were considered as endothelial and produced a collagen-positive layer resembling a basement membrane. Detection of CD31+/CD34+ cells at the early stages with subsequent loss of CD34 indicated cell adhesion from the bloodstream. Therefore, either conjugation with RGD peptides or the incorporation of VEGF promoted the formation of a functional endothelial cell layer. Furthermore, both modifications increased primary patency rate three-fold. In conclusion, both of these biofunctionalization approaches can be considered as equally efficient for the modification of tissue-engineered vascular grafts.

  4. Engineering an endothelialized vascular graft: a rational approach to study design in a non-human primate model.

    Directory of Open Access Journals (Sweden)

    Deirdre E J Anderson

    Full Text Available After many years of research, small diameter, synthetic vascular grafts still lack the necessary biologic integration to perform ideally in clinical settings. Endothelialization of vascular grafts has the potential to improve synthetic graft function, and endothelial outgrowth cells (EOCs are a promising autologous cell source. Yet no work has established the link between endothelial cell functions and outcomes of implanted endothelialized grafts. This work utilized steady flow, oscillatory flow, and tumor necrosis factor stimulation to alter EOC phenotype and enable the formulation of a model to predict endothelialized graft performance. To accomplish this, EOC in vitro expression of coagulation and inflammatory markers was quantified. In parallel, in non-human primate (baboon models, the platelet and fibrinogen accumulation on endothelialized grafts were quantified in an ex vivo shunt, or the tissue ingrowth on implanted grafts were characterized after 1mth. Oscillatory flow stimulation of EOCs increased in vitro coagulation markers and ex vivo platelet accumulation. Steady flow preconditioning did not affect platelet accumulation or intimal hyperplasia relative to static samples. To determine whether in vitro markers predict implant performance, a linear regression model of the in vitro data was fit to platelet accumulation data-correlating the markers with the thromboprotective performance of the EOCs. The model was tested against implant intimal hyperplasia data and found to correlate strongly with the parallel in vitro analyses. This research defines the effects of flow preconditioning on EOC regulation of coagulation in clinical vascular grafts through parallel in vitro, ex vivo, and in vivo analyses, and contributes to the translatability of in vitro tests to in vivo clinical graft performance.

  5. New Insights into Dialysis Vascular Access: Molecular Targets in Arteriovenous Fistula and Arteriovenous Graft Failure and Their Potential to Improve Vascular Access Outcomes.

    Science.gov (United States)

    Lee, Timmy; Misra, Sanjay

    2016-08-08

    Vascular access dysfunction remains a major cause of morbidity and mortality in hemodialysis patients. At present there are few effective therapies for this clinical problem. The poor understanding of the pathobiology that leads to arteriovenous fistula (AVF) and graft (AVG) dysfunction remains a critical barrier to development of novel and effective therapies. However, in recent years we have made substantial progress in our understanding of the mechanisms of vascular access dysfunction. This article presents recent advances and new insights into the pathobiology of AVF and AVG dysfunction and highlights potential therapeutic targets to improve vascular access outcomes. Copyright © 2016 by the American Society of Nephrology.

  6. Development and evaluation of elastomeric hollow fiber membranes as small diameter vascular graft substitutes

    Energy Technology Data Exchange (ETDEWEB)

    Mercado-Pagán, Ángel E.; Kang, Yunqing [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Findlay, Michael W. [Department of Plastic and Reconstructive Surgery, Stanford University, Stanford, CA (United States); University of Melbourne Department of Surgery, Royal Melbourne Hospital, Parkville, VIC (Australia); Yang, Yunzhi, E-mail: ypyang@stanford.edu [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States)

    2015-04-01

    Engineering of small diameter (< 6 mm) vascular grafts (SDVGs) for clinical use remains a significant challenge. Here, elastomeric polyester urethane (PEU)-based hollow fiber membranes (HFMs) are presented as an SDVG candidate to target the limitations of current technologies and improve tissue engineering designs. HFMs are fabricated by a simple phase inversion method. HFM dimensions are tailored through adjustments to fabrication parameters. The walls of HFMs are highly porous. The HFMs are very elastic, with moduli ranging from 1–4 MPa, strengths from 1–5 MPa, and max strains from 300–500%. Permeability of the HFMs varies from 0.5–3.5 × 10{sup −6} cm/s, while burst pressure varies from 25 to 35 psi. The suture retention forces of HFMs are in the range of 0.8 to 1.2 N. These properties match those of blood vessels. A slow degradation profile is observed for all HFMs, with 71 to 78% of the original mass remaining after 8 weeks, providing a suitable profile for potential cellular incorporation and tissue replacement. Both human endothelial cells and human mesenchymal stem cells proliferate well in the presence of HFMs up to 7 days. These results demonstrate a promising customizable PEU HFMs for small diameter vascular repair and tissue engineering applications. - Highlights: • Hollow fiber membranes (HFMs) were fabricated and evaluated. • HFM properties could be tailored through adjustments to fabrication parameters. • Properties could match or exceed those of blood vessels. • HFM showed excellent compatibility in vitro. • HFMs have the potential to be used for small diameter vascular grafts.

  7. Development of endothelium-denuded human umbilical veins as living scaffolds for tissue-engineered small-calibre vascular grafts.

    Science.gov (United States)

    Hoenicka, Markus; Schrammel, Siegfried; Bursa, Jiri; Huber, Georgine; Bronger, Holger; Schmid, Christof; Birnbaum, Dietrich E

    2013-04-01

    Tissue-engineered small-calibre vessel grafts may help to alleviate the lack of graft material for coronary and peripheral bypass grafting in an increasing number of patients. This study explored the use of endothelium-denuded human umbilical veins (HUVs) as scaffolds for vascular tissue engineering in a perfusion bioreactor. Vessel diameter (1.2 ± 0.4 mm), wall thickness (0.38 ± 0.09 mm), uniaxial ultimate failure stress (8029 ± 1714 kPa) and burst pressure (48.4 ± 20.2 kPa, range 28.4-83.9 kPa) were determined in native samples. The effects of endothelium removal from HUVs by enzymatic digestion, hypotonic lysis and dehydration were assessed. Dehydration did not significantly affect contractile function, tetrazolium dye reduction, mechanical strength and vessel structure, whereas the other methods failed in at least one of these parameters. Denudation by dehydration retained laminin, fibronectin, collagen and elastic fibres. Denuded HUVs were seeded in a perfusion bioreactor with either allogeneic HUVs endothelial cells or with saphenous vein endothelial cells harvested from patients with coronary artery disease. Seeding in a perfusion bioreactor resulted in a confluent monolayer of endothelial cells from both sources, as judged by histology and scanning electron microscopy. Seeded cells contained von Willebrand factor and CD31. In conclusion, denuded HUVs should be considered an alternative to decellularized blood vessels, as the process keeps the smooth muscle layer intact and functional, retains proteins relevant for biomechanic properties and for cell attachment and provides a suitable scaffold for seeding an autologous and flow-resistant endothelium. Copyright © 2012 John Wiley & Sons, Ltd.

  8. Comparative study of three vascular grafts produced by electrospinning in vitro and in vivo

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    И. В. Попова

    2016-01-01

    Full Text Available Objective. The study focused on the production and evaluation of small-diameter vascular grafts (less than 6 mm by using an electrospinning approach.Methods. The protocols of vascular grafts (VG to be produced from the solutions of synthetic polymers and their blends with gelatin including those with a semipermeable inner layer were developed. The comparative study of the grafts in vitro and in vivo was carried out. The resistance of VG to displacement, suture retention, layers snagging and compatibility with native artery walls were studied. Also assessed was the time of hemostasis when implanting the grafts consisting of various mixes of polymers, as well as their biocompatibility at different stages of observation.Results. VG produced by electrospinning and containing a semipermeable inner layer possess satisfactory mechanical properties, such as suture retention, resistance to displacement, stability during long term pulsatile stress, do not snag during implantation and form a tight contact with native artery walls. A histological study demonstrates active remodeling of VG including the growth of inner structure typical of a vessel, medium collagen/elastin layer with smooth muscle cells and synthetic fibers and an outer connective tissue capsule without any signature of inflammation. An immunohistochemical study demonstrates more efficient accumulation of smooth muscle cells in VG produced from polycaprolactone (PCL as compared to other VG tested. VG produced from the PCL-gelatin blend and containing an inner semipermeable layer, as well as similar VG containing polylactic-co-glycolic acid (PLGA in the inner semipermeable layer tended to produce an endothelial inner layer faster as compared to VG from PCL. However, VG with PLGA acid had a tendency to loose endothelial cells, possibly due to PLGA degradation. VG produced from PCL-gelatin blend and containing the inner semipermeable layer demonstrate limited accumulation of smooth muscle cells

  9. [Wrist joint reconstruction with vascularized fibular head graft after resection of distal radius giant cell tumor].

    Science.gov (United States)

    Bi, Zhenggang; Pan, Qi; Fu, Chunjiang; Han, Xinguang

    2010-12-01

    To observe the effectiveness of wrist joint reconstruction with vascularized fibular head graft after resection of distal radius giant cell tumor. Between March 2000 and March 2009, 31 cases of distal radius giant cell tumor were treated with extended resection and vascularized fibular head graft for repairing defects of the distal radius, and reconstructing wrist joint. There were 14 males and 17 females with an average age of 37.2 years (range, 15-42 years). The disease duration ranged from 1 month to 2 years and 3 months with an average of 8 months. The size of tumor was 6.5 cm x 3.5 cm-8.0 cm x 4.5 cm. The range of motion (ROM) of wrist joint was as follows: extension 5-15 degrees (mean, 10.7 degrees), flexion 9-21 degrees (mean, 14.2 degrees), radial inclination 0-10 degrees (mean, 8.6 degrees), and ulnar inclination 0-15 degrees (mean, 7.9 degrees). The ROM of forearm was as follows: pronation 15-50 degrees (mean, 28.7 degrees) and supination 10-25 degrees (mean, 16.5 degrees). The histopathological examination revealed that there were 5 cases of stage I, 17 of stage II, and 9 of stage III. All patients achieved primary healing of incision and were followed up 1-9 years with an average of 4.5 years. The X-ray films showed that bone healing time was 12-16 weeks with an average of 13 weeks. No tumors recurrence was observed. The ROM of wrist joint was as follows at 1 year after operation: extension 20-50 degrees (mean, 29.0 degrees), flexion 30-50 degrees (mean, 35.0 degrees), radial inclination 10-20 degrees (mean, 16.5 degrees), and ulnar inclination 20-25 degrees (mean, 23.5 degrees). The ROM of forearm was as follows: pronation 40-90 degrees (mean, 68.3 degrees) and supination 30-80 degrees (mean, 59.6 degrees). There were significant differences in the ROM between before operation and after operation (P wrist score, the results were excellent in 17 cases, good in 12, and fair in 2. Wrist joint reconstruction with vascularized fibular head graft can restore

  10. Autogenous femoral head as grafting material for mandibular augmentation

    NARCIS (Netherlands)

    Vos, M. D.; Raghoebar, G. M.; van der Wal, J. E.; Kalk, W. W. I.; Vissink, A.

    2009-01-01

    Bone grafting is commonly used for augmentation of the atrophic edentulous maxilla and mandible. Although bone substitutes and allogeneic frozen bone grafts have been applied successfully, fresh autogenous bone grafts remain the 'gold standard' in maxillofacial reconstructive surgery. A disadvantage

  11. Evaluating effectiveness of antibiotic polymethylmethacrylate beads in achieving wound sterilization and graft preservation in patients with early and late vascular graft infections.

    Science.gov (United States)

    Poi, Mun Jye; Pisimisis, George; Barshes, Neal R; Darouiche, Rabih O; Lin, Peter H; Kougias, Panagiotis; Bechara, Carlos Fares

    2013-05-01

    The objective of the study was to evaluate the effectiveness of antibiotic-based polymethylmethacrylate (ab-PMMA) beads in achieving wound sterilization and graft preservation in patients with vascular graft infections. We reviewed 31 patients treated for 37 graft infections over the past 5 years using ab-PMMA beads in a single institution. All patients were started on broad-spectrum antibiotics and later switched to targeted therapy based on intraoperative cultures for at least 6 weeks. All patients underwent multiple planned wound explorations, debridements and washouts. Cultures were obtained each time. Decision to do formal closure depended on culture results and wound appearance. All wounds were closed with a muscle flap. The endpoints included wound sterilization, limb salvage, recurrence of infection, and graft preservation. A total of 19 different organisms were cultured, and 48.6% of cases were polymicrobial, thereby accounting for a total of 60 isolates. The majority (n = 27) received a mix of tobramycin/vancomycin PMMA beads; vancomycin beads (n = 5); tobramycin beads (n = 1); and gentamicin/vancomycin beads (n = 4). Wound sterilization based on cultures was achieved in 32 of 34 wounds (94.1%). Of the cases, 5 underwent early graft removal, 3 with immediate reconstruction, and 1 case underwent a major amputation (2.7 %). Graft preservation was attempted in 32 cases (86.5%). No death occurred within 30 days. Limb salvage was achieved in 28 of the 32 preserved graft cases (87.5%) at a mean follow-up of 26 months (6 to 51 months). The long-term limb salvage rate for the cohort was 86.5%. Of the patients, 4 presented with recurrent graft infection and occlusion, causing acute limb ischemia and resulting in major amputation. The reinfection rate was 12.5% in the graft-preservation group and 11.4% in both the graft-preserved and the in situ replacement groups. Sterilization of graft infection can be achieved with ab-PMMA beads followed by closure with muscle

  12. Retrograde catheterization of haemodialysis fistulae and grafts: angiographic depiction of the entire vascular access tree and stenosis treatment

    NARCIS (Netherlands)

    Duijm, Lucien E. M.; Overbosch, Evert H.; Liem, Ylian S.; Planken, Robrecht N.; Tordoir, Jan H. M.; Cuypers, Philippe W. M.; Douwes-Draaijer, Petra; de Haan, Michiel W.

    2009-01-01

    BACKGROUND: The European Best Practice Guidelines on Vascular Access propose magnetic resonance angiography (MRA) of dysfunctional dialysis fistulae and grafts if visualization of the complete arterial inflow and outflow vessels is needed. In a prospective multi-centre study we determined the

  13. Decellularized ureter for tissue-engineered small-caliber vascular graft.

    Science.gov (United States)

    Narita, Yuji; Kagami, Hideaki; Matsunuma, Hiroshi; Murase, Yosuke; Ueda, Minoru; Ueda, Yuichi

    2008-01-01

    Previous attempts to create small-caliber vascular prostheses have been limited. The aim of this study was to generate tissue-engineered small-diameter vascular grafts using decellularized ureters (DUs). Canine ureters were decellularized using one of four different chemical agents [Triton-X 100 (Tx), deoxycholate (DCA), trypsin, or sodium dodecyl sulfate (SDS)] and the histology, residual DNA contents, and immunogenicity of the resulting DUs were compared. The mechanical properties of the DUs were evaluated in terms of water permeability, burst strength, tensile strength, and compliance. Cultured canine endothelial cells (ECs) and myofibroblasts were seeded onto DUs and evaluated histologically. Canine carotid arteries were replaced with the EC-seeded DUs (n = 4). As controls, nonseeded DUs (n = 5) and PTFE prostheses (n = 4) were also used to replace carotid arteries. The degree of decellularization and the maintenance of the matrix were best in the Tx-treated DUs. Tx-treated and DCA-treated DUs had lower remnant DNA contents and immunogenicity than the others. The burst strength of the DUs was more than 500 mmHg and the maximum tensile strength of the DUs was not different to that of native ureters. DU compliance was similar to that of native carotid artery. The cell seeding test resulted in monolayered ECs and multilayered alpha-smooth muscle actin-positive cells on the DUs. The animal implantation model showed that the EC-seeded DUs were patent for at least 6 months after the operation, whereas the nonseeded DUs and PTFE grafts become occluded within a week. These results suggest that tissue-engineered DUs may be a potential alternative conduit for bypass surgery.

  14. A Review on the Hemodialysis Reliable Outflow (HeRO) Graft for Haemodialysis Vascular Access.

    Science.gov (United States)

    Al Shakarchi, J; Houston, J G; Jones, R G; Inston, N

    2015-07-01

    With improved dialysis survival there are increasing numbers of patients who have exhausted definitive access options due to central venous stenosis and are maintaining dialysis on a central venous catheter. The Hemodialysis Reliable Outflow (HeRO) allows an alternative by providing a definitive access solution. The aim of this study is to systematically review the published outcomes of the HeRO graft and discuss the role in complex haemodialysis patients. Electronic databases were searched for studies assessing the use of the HeRO graft for dialysis in accordance with PRISMA published up to December 31 2014. The primary outcomes for this study were 1-year primary and secondary patency rates. Secondary outcomes were rates of dialysis access associated steal syndrome, HeRO-related bacteraemia rates and rates of interventions. Following strict inclusion/exclusion criteria, eight studies including 409 patients were included in our review. Primary and secondary pooled patency rates in this complex cohort of dialysis patients were found to be 21.9% (9.6-37.2%) and 59.4% (39.4-78%). The rate of dialysis access associated steal syndrome was low at 6.3% (1-14.7%) as was the range of HeRO-related bacteraemia (0.13-0.7 events per 1000 days). This literature review shows that the HeRO graft is an acceptable option for complex dialysis patients who are catheter dependent. Owing to device availability, published data are predominantly North American and further longer-term studies in other populations may be necessary. In this challenging patient group, randomized controlled trials are required to allow comparisons with alternative access options. Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  15. Promising Poly(ε-caprolactone Composite Reinforced with Weft-Knitted Polyester for Small-Diameter Vascular Graft Application

    Directory of Open Access Journals (Sweden)

    Fu-Jun Wang

    2014-01-01

    Full Text Available The present study was designed to improve the mechanical performance of a small-diameter vascular prosthesis made from a flexible membrane of poly(ε-caprolactone (PCL. PCL reinforcement was achieved by embedding a tubular fabric knitted from polyethylene terephthalate (PET yarns within the freeze-dried composite structure. The knitting density of PET fabric influenced the mechanical properties of the new vascular graft. Results showed that the composite prototype has good mechanical properties, water permeability, elastic recovery, and suture retention strength. Increases in loop density increased compressive strength and suture retention strength and decreased elastic recovery. The new composite prototype vascular graft has promising potential applications in clinics because of its excellent mechanical properties.

  16. Effects of hot water treatments on dormant grapevine propagation materials used for grafted vine production

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    Soltekin Oguzhan

    2017-01-01

    Full Text Available Agrobacterium vitis is responsible for the crown gall disease of grapevine which breaks the grapevine trunk vascular system. Nutrient flow is prevented by crown gall and it leads to weak growth and death of the plants. It can be destructive disease often encountered in vineyards and it can be spread in cuttings for propagation. Thermotherapy treatment is an alternative method for eradicating A. vitis from grapevine cuttings but effects of thermotherapy treatments on dormant vine tissue, bud vitality, rooting and shooting of the propagation materials are not yet fully understood. In this research, it is aimed to determine the effects of thermotherapy treatment (Hot water treatment on callus formation (at the basal part and grafting point, grafted vine quality (shoot length, shoot width, root number, shooting and rooting development, fresh and dry weight of shoots and roots and final take in the grafted vine production. Experiment was conducted in the nursery of Manisa Viticultural Research Institute. Rootstocks (Kober 5BB, Couderc 1613 and 41B and scions (Sultan 7 and Manisa sultanı were hot-water treated at 50°C for 30 minutes which is the most common technique against Agrobacterium vitis. After thermotherapy treatment, all rootstocks were grafted with Sultan 7 and Manisa sultanıvarieties. They were kept for 22 days in callusing room for callus development and then they were planted in polyethlyene bags for rooting. At the end of the study, significant treatment x rootstock interaction were observed for the final take of Sultan 7 variety. Thermotherapy treated of 1613C/Sultan 7 combinations had more final take than the control (untreated group. For instance, hot water treated cuttings of 1613C/Sultan 7 combinations had 75% final take while the control group had the 70%. Also there were not observed any adverse effects of HWT on bud and tissue vitality.

  17. Conjugation with RGD Peptides and Incorporation of Vascular Endothelial Growth Factor Are Equally Efficient for Biofunctionalization of Tissue-Engineered Vascular Grafts.

    Science.gov (United States)

    Antonova, Larisa V; Seifalian, Alexander M; Kutikhin, Anton G; Sevostyanova, Victoria V; Matveeva, Vera G; Velikanova, Elena A; Mironov, Andrey V; Shabaev, Amin R; Glushkova, Tatiana V; Senokosova, Evgeniya A; Vasyukov, Georgiy Yu; Krivkina, Evgeniya O; Burago, Andrey Yu; Kudryavtseva, Yuliya A; Barbarash, Olga L; Barbarash, Leonid S

    2016-11-16

    The blend of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly(ε-caprolactone) (PCL) has recently been considered promising for vascular tissue engineering. However, it was shown that PHBV/PCL grafts require biofunctionalization to achieve high primary patency rate. Here we compared immobilization of arginine-glycine-aspartic acid (RGD)-containing peptides and the incorporation of vascular endothelial growth factor (VEGF) as two widely established biofunctionalization approaches. Electrospun PHBV/PCL small-diameter grafts with either RGD peptides or VEGF, as well as unmodified grafts were implanted into rat abdominal aortas for 1, 3, 6, and 12 months following histological and immunofluorescence assessment. We detected CD31⁺/CD34⁺/vWF⁺ cells 1 and 3 months postimplantation at the luminal surface of PHBV/PCL/RGD and PHBV/PCL/VEGF, but not in unmodified grafts, with the further observation of CD31⁺CD34-vWF⁺ phenotype. These cells were considered as endothelial and produced a collagen-positive layer resembling a basement membrane. Detection of CD31⁺/CD34⁺ cells at the early stages with subsequent loss of CD34 indicated cell adhesion from the bloodstream. Therefore, either conjugation with RGD peptides or the incorporation of VEGF promoted the formation of a functional endothelial cell layer. Furthermore, both modifications increased primary patency rate three-fold. In conclusion, both of these biofunctionalization approaches can be considered as equally efficient for the modification of tissue-engineered vascular grafts.

  18. Proteomic study related to vascular connections in watermelon scions grafted onto bottle-gourd rootstock under different light intensities.

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    Sowbiya Muneer

    Full Text Available Although grafting is broadly used in the production of crops, no information is available about the proteins involved in vascular connections between rootstock and scion. Similarly, proteome changes under the light intensities widely used for grafted seedlings are of practical use. The objective of this study was to determine the proteome of vascular connections using watermelon (Citrullus vulgaris Schrad. 'Sambok Honey' and 'Speed' as the scion and bottle gourd (Lagenaria siceraria Stanld. 'RS Dongjanggun' as the rootstock grown under different light intensities (25, 50, 75 and 100 μmol m-2 s-1. Our proteomic analysis revealed 24 and 27 differentially expressed proteins in 'Sambok Honey' and 'Speed', respectively, under different light intensities. The identified proteins were largely involved in ion binding, amino acid metabolism, transcriptional regulation and defense response. The enhancement of ion-binding, transcriptional regulation, amino acid metabolism, and defense response proteins suggests a strengthening of the connection between the rootstock and scion under high light intensity. Indeed, the accumulation of key enzymes in the biological processes described above appears to play an important role in the vascular connections of grafted seedlings. Moreover, it appears that 100 μmol m-2 s-1 results in better protein expression responses in grafted seedlings.

  19. The Vascularized Fibular Graft in the Pediatric Upper Extremity: A Durable, Biological Solution to Large Oncologic Defects

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    Nicki Zelenski

    2013-01-01

    Full Text Available Skeletal reconstruction after large tumor resection is challenging. The free vascularized fibular graft (FVFG offers the potential for rapid autograft incorporation as well as growing physeal transfer in pediatric patients. We retrospectively reviewed eleven pediatric patients treated with FVFG reconstructions of the upper extremity after tumor resection. Eight male and three female patients were identified, including four who underwent epiphyseal transfer. All eleven patients retained a functional salvaged limb. Nonunion and graft fracture were the most common complications relating to graft site (27%. Peroneal nerve palsy occurred in 4/11 patients, all of whom received epiphyseal transfer. Patients receiving epiphyseal transplant had a mean annual growth of 1.7 cm/year. Mean graft hypertrophy index increased by more than 10% in all cases. Although a high complication rate may be anticipated, the free vascularized fibula may be used to reconstruct large skeletal defects in the pediatric upper extremity after oncologic resection. Transferring the vascularized physis is a viable option when longitudinal growth is desired.

  20. Combined strategy of endothelial cells coating, Sertoli cells coculture and infusion improves vascularization and rejection protection of islet graft.

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    Yang Li

    Full Text Available Improving islet graft revascularization and inhibiting rejection become crucial tasks for prolonging islet graft survival. Endothelial cells (ECs are the basis of islet vascularization and Sertoli cells (SCs have the talent to provide nutritional support and exert immunosuppressive effects. We construct a combined strategy of ECs coating in the presence of nutritious and immune factors supplied by SCs in a co-culture system to investigate the effect of vascularization and rejection inhibition for islet graft. In vivo, the combined strategy improved the survival and vascularization as well as inhibited lymphocytes and inflammatory cytokines. In vitro, we found the combinatorial strategy improved the function of islets and the effect of ECs-coating on islets. Combined strategy treated islets revealed higher levels of anti-apoptotic signal molecules (Bcl-2 and HSP-32, survival and function related molecules (PDX-1, Ki-67, ERK1/2 and Akt and demonstrated increased vascular endothelial growth factor receptor 2 (KDR and angiogenesis signal molecules (FAk and PLC-γ. SCs effectively inhibited the activation of lymphocyte stimulated by islets and ECs. Predominantly immunosuppressive cytokines could be detected in culture supernatants of the SCs coculture group. These results suggest that ECs-coating and Sertoli cells co-culture or infusion synergistically enhance islet survival and function after transplantation.

  1. Vascular graft employment in the surgical treatment of acute and chronic acromio-clavicular dislocation.

    Science.gov (United States)

    Vitali, Matteo; Pedretti, Alberto; Naim Rodriguez, Nadim; Franceschi, Alessandro; Fraschini, Gianfranco

    2015-10-01

    To show the efficiency and safety of a surgical treatment in both acute and chronic acromio-clavicular junction (ACJ) dislocations. Retrospective. Department of Orthopedics and Traumatology at IRCCS San Raffaele Hospital. This study was performed on 37 subjects classified as Rockwood grade III-V or Tossy III ACJ dislocation. The surgical treatment was carried out by placing a vascular graft (GorePropaten(®)) between the tip of the coracoid process and the mid-lateral side of the clavicle with two temporary percutaneous K-wires positioned in a parallel manner in the AC ligament through the acromion and clavicle for 30 days to improve stability. Outcomes were assessed using the Constant Shoulder (CS) score, DASH score, subjective satisfaction, and stability of AC joint at 24 months. UCLA scores taken preoperatively and at 15-month follow-up were used to perform statistical analysis significance using a control group treated conservatively. Postoperative X-rays were examined to assess joint stability after 24 months. Preoperative CS score was 51 ± 12 in the acute group and 55 ± 15 in the chronic group. Follow-up mean CS score was 88 ± 11 in the acute group and 82 ± 20 in the chronic group at 24 months. Preoperative DASH score was 19 ± 3 in the acute group and 14 ± 5 in the chronic group. Mean DASH score was 3.60 ± 7 in the acute group and 6.42 ± 6 in the chronic group. Preoperative UCLA scores were 14.6 ± 2 and 15 ± 7 in the acute group and chronic group, respectively. At 15-month follow-up, UCLA scores of 28.1 ± 1.9 and 27.7 ± 1 in the acute and chronic group, respectively, showed a significant improvement (p partial re-dislocation at the 24-month X-ray follow-up. No infections, either deep or superficial, or nerve palsies were reported. Given the results obtained during the study and the response of the patients in both acute and chronic groups, the authors found that the employment of a vascular graft combined with temporary percutaneous K-wires is

  2. Journey of bone graft materials in periodontal therapy: A chronological review

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    Jitendra Kumar

    2016-01-01

    Full Text Available Bone, the basic building block of the healthy periodontium, is affected in most of the periodontal diseases and can be managed either by mechanically recontouring it or by grafting techniques, which encourages regeneration where it has been lost. Bone replacement grafts are widely used to promote bone formation and periodontal regeneration. Bone grafting, placing bone or bone substitutes into defects created by the disease process, acts like a scaffold upon which the body generates its own, new bone. A wide range of bone grafting materials, including bone grafts and bone graft substitutes, have been applied and evaluated clinically, including autografts, allografts, xenografts, and alloplasts. This review provides an overview of the clinical application, biologic function, and advantages and disadvantages of various types of bone graft materials used in periodontal therapy till date with emphasis on recent advances in this field.

  3. Grafting of acrylonitrile onto cellulosic material derived from bamboo (Dendrocalamus strictus

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    2008-01-01

    Full Text Available Bamboo, a lignocellulosic biopolymer material, is of interest as feedstock for production of cellulose derivatives by chemical functionalization. Optimization of grafting of acrylonitrile onto cellulosic material (average Degree of Polymerization 816, isolated from bamboo (Dendrocalamus stictus was performed by varying the process parameters such as duration of soaking of cellulosic material in ceric ammonium nitrate solution, ceric ammonium nitrate concentration, polymerization time, temperature of reaction and acrylonitrile concentration to study their influence on percent grafting and grafting efficiency. Graft copolymerization of acrylonitrile onto cellulosic material derived from bamboo (Dendrocalamus strictus in heterogenous medium can be initiated effectively with ceric ammonium nitrate. The optimum reaction conditions obtained for grafting of acrylonitrile onto cellulosic material were: duration of dipping cellulosic material in ceric ammonium nitrate solution 1 hr, ceric ammonium nitrate concentration 0.02 M, acrylonitrile concentration 24.6 mol/anhydroglucose unit, temperature of reaction 40°C and polymerization time 4 hrs. The percent grafting for optimized samples is 210.3% and grafting efficiency is 97%. The characterization of the grafted products by means of FTIR and Scanning Electron Microscopy furnished the evidence of grafting of acrylonitrile onto the cellulosic material.

  4. Pressurized vascular systems for self-healing materials.

    Science.gov (United States)

    Hamilton, A R; Sottos, N R; White, S R

    2012-05-07

    An emerging strategy for creating self-healing materials relies on embedded vascular networks of microchannels to transport reactive fluids to regions of damage. Here we investigate the use of active pumping for the pressurized delivery of a two-part healing system, allowing a small vascular system to deliver large volumes of healing agent. Different pumping strategies are explored to improve the mixing and subsequent polymerization of healing agents in the damage zone. Significant improvements in the number of healing cycles and in the overall healing efficiency are achieved compared with prior passive schemes that use only capillary forces for the delivery of healing agents. At the same time, the volume of the vascular system required to achieve this superior healing performance is significantly reduced. In the best case, nearly full recovery of fracture toughness is attained throughout 15 cycles of damage and healing, with a vascular network constituting just 0.1 vol% of the specimen.

  5. Shear stress with appropriate time-step and amplification enhances endothelial cell retention on vascular grafts.

    Science.gov (United States)

    Liu, Haifeng; Gong, Xianghui; Jing, Xiaohui; Ding, Xili; Yao, Yuan; Huang, Yan; Fan, Yubo

    2017-11-01

    Endothelial cells (ECs) are sensitive to changes in shear stress. The application of shear stress to ECs has been well documented to improve cell retention when placed into a haemodynamically active environment. However, the relationship between the time-step and amplification of shear stress on EC functions remains elusive. In the present study, human umbilical cord veins endothelial cells (HUVECs) were seeded on silk fibroin nanofibrous scaffolds and were preconditioned by shear stress at different time-steps and amplifications. It is shown that gradually increasing shear stress with appropriate time-steps and amplification could improve EC retention, yielding a complete endothelial-like monolayer both in vitro and in vivo. The mechanism of this improvement is mediated, at least in part, by an upregulation of integrin β1 and focal adhesion kinase (FAK) expression, which contributed to fibronectin (FN) assembly enhancement in ECs in response to the shear stress. A modest gradual increase in shear stress was essential to allow additional time for ECs to gradually acclimatize to the changing environment, with the goal of withstanding the physiological levels of shear stress. This study recognized that the time-steps and amplifications of shear stress could regulate EC tolerance to shear stress and the anti-thrombogenicity function of engineered vascular grafts via an extracellular cell matrix-specific, mechanosensitive signalling pathway and might prevent thrombus formation in vivo. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Gelatine and gelatine/elastin nanocomposites for vascular grafts: processing and characterization.

    Science.gov (United States)

    Lamprou, Dimitris; Zhdan, Peter; Labeed, Fatima; Lekakou, Constantina

    2011-08-01

    This study involves the preparation, microstructural, physical, mechanical, and biological characterization of novel gelatine and gelatine/elastin gels for their use in the tissue engineering of vascular grafts. Gelatine and gelatine/elastin nanocomposite gels were prepared via a sol-gel process, using soluble gelatine. Gelatine was subsequently cross-linked by leaving the gels in 1% glutaraldehyde. The cross-linking time was optimized by assessing the mass loss of the cross-linked gels in water and examining their mechanical properties in dynamic mechanical tests. Atomic force microscopy (AFM) studies revealed elastin nanodomains, homogeneously distributed and embedded in a bed of gelatine nanofibrils in the 30/70 elastin/gelatine gel. It was concluded that the manufactured nanocomposite gels resembled natural arteries in terms of microstructure and stiffness. The biological characterization involved the culture of rat smooth muscle cells (SMCs) on tubular gelatine and gelatine/ elastin nanocomposite gels, and measurements of the scaffold diameter and the cell density as a function of time.

  7. The Effect of Postoperative Corticosteroid Administration on Free Vascularized Fibular Grafting for Treating Osteonecrosis of the Femoral Head

    OpenAIRE

    Hao Ding; Sheng-Bao Chen; Sen Lin; You-Shui Gao; Chang-Qing Zhang

    2013-01-01

    Free vascularized fibular grafting (FVFG) has been reported to be an effective method of treating osteonecrosis of the femoral head (ONFH). This study evaluated whether postoperative maintenance doses of corticosteroids had an adverse effect on FVFG outcomes in patients with corticosteroid-induced ONFH. We retrospectively reviewed the records of 39 patients (67 hips) who had received maintenance doses of corticosteroids following FVFG. This group was matched to a group of patients who had not...

  8. The Vascularized Fibular Graft in the Pediatric Upper Extremity: A Durable, Biological Solution to Large Oncologic Defects

    OpenAIRE

    Zelenski, Nicki; Brigman, Brian E.; Levin, L. Scott; Erdmann, Detlev; Eward, William C.

    2013-01-01

    Skeletal reconstruction after large tumor resection is challenging. The free vascularized fibular graft (FVFG) offers the potential for rapid autograft incorporation as well as growing physeal transfer in pediatric patients. We retrospectively reviewed eleven pediatric patients treated with FVFG reconstructions of the upper extremity after tumor resection. Eight male and three female patients were identified, including four who underwent epiphyseal transfer. All eleven patients retained a fun...

  9. Streptococcus milleri group infection associated with digestive fistula in patients with vascular graft: report of seven cases and review.

    Science.gov (United States)

    Bonnet, E P; Arista, S; Archambaud, M; Boot, B; Clave, D; Massip, P; Marchou, B

    2007-06-01

    We described seven patients with Streptococcus milleri group aortic (six patients) or vena cava (one patient) graft infection secondary to a vasculo-digestive fistula. Time between vascular graft setting and first clinical signs varied from eight months to more than thirteen years. Six patients had fever. Three patients presented with recurrent fever for more than nine months and in two of these cases, delay before diagnosis was long because repeated blood cultures were sterile. Three patients had abdominal pain and/or digestive haemorrhage. Abdominal CT-scan S. milleri was not contributive for the diagnosis in four patients. Streptococcus anginosus was isolated in four patients, Streptococcus constellatus in three patients. One patient died before surgical management. The other six patients were cured by a surgical management associated with a prolonged antibiotic (lactams) treatment. S. milleri group graft infections are rare (or misdiagnosed) while we found only 4 similar cases in the English medical literature. We conclude that a peri-prosthetic infection secondary to a digestive fistula must be insistently searched (and blood cultures must be repeated many times) in any patient with an aortic (or any other vascular) graft presenting prolonged or recurrent fever or acute digestive symptoms.

  10. Aspirin-loaded electrospun poly(ε-caprolactone) tubular scaffolds: potential small-diameter vascular grafts for thrombosis prevention.

    Science.gov (United States)

    Del Gaudio, Costantino; Ercolani, Enrico; Galloni, Pierluca; Santilli, Federico; Baiguera, Silvia; Polizzi, Leonardo; Bianco, Alessandra

    2013-02-01

    Thrombosis is the main cause of failure of small-diameter synthetic vascular grafts when used for by-pass procedures. The development of bioresorbable vascular scaffolds with localized and sustained intra-luminal antithrombotic drug release could be considered a desirable improvement towards a valuable solution for this relevant clinical need. For this aim, we present the fabrication and characterization of aspirin-loaded electrospun poly(ε-caprolactone) tubular scaffolds as a vascular drug-delivery graft. Three different drug concentrations were considered (i.e., 1, 5 or 10 % w/w). Although a fibrous structure was clearly observed for all the collected scaffolds, aspirin content was directly implied in the final microstructure leading to a bimodal fiber diameter distribution and fused fibers at crossing-points (5 or 10 % w/w). Mechanical response highlighted a direct relationship for modulus and stress at break with the aspirin content, while the elongation at break was not remarkably different for the investigated cases. The temporal drug release was strongly dependent from the amount of loaded aspirin, reaching a steady state release after about 50 h. Finally, the adhesion assay confirmed the capability of the electrospun scaffolds to reduce platelet adhesion/aggregation onto aspirin loaded polymeric fibers. Aspirin-loaded electrospun tubular scaffold could represent a feasible candidate to develop a novel bioresorbable drug-releasing graft for small-diameter vessel replacements.

  11. Man as a Living Bioreactor: Prefabrication of a Custom Vascularized Bone Graft in the Gastrocolic Omentum.

    Science.gov (United States)

    Wiltfang, Jörg; Rohnen, Michael; Egberts, Jan-Hendrik; Lützen, Ulf; Wieker, Henning; Açil, Yahya; Naujokat, Hendrik

    2016-08-01

    Reconstruction of critical-size jaw defects still remains challenging. The standard treatment today is transplantation of autologous bone grafts, which is associated with high donor-site morbidity and unsatisfactory outcomes. We aimed to reconstruct a mandibular discontinuity defect after ablative surgery using the gastrocolic omentum as a bioreactor for heterotopic ossification. Three-dimensional computed tomography data were used to produce an ideal virtual replacement for the mandibular defect. A titanium mesh cage was filled with bone mineral blocks, infiltrated with 12 mg of recombinant human bone morphogenetic protein 2, and enriched with bone marrow aspirate. The scaffold was implanted into the gastrocolic omentum, and 3 months later, a free flap was harvested to reconstruct the mandibular defect. In vivo single photon emission computed tomography/computed tomography revealed bone remodeling and mineralization inside the mandibular transplant during prefabrication and after transplantation. Reconstruction was possible without any further modifications of the graft. A histological evaluation revealed that large sections of the Bio-Oss material were covered with osteoid matrix 3 months after transplantation. The quality of life of the patient significantly increased with acquisition of the ability to masticate and the improvement in pronunciation and aesthetics. Heterotopic bone induction to form a mandibular replacement inside the gastrocolic omentum is possible in human subjects. Heterotopic prefabrication is associated with many advantages, like allowing a reduced operative burden compared with conventional techniques and good three-dimensional outcomes.

  12. New concepts and materials in microvascular grafting: prosthetic graft endothelial cell seeding and gene therapy.

    Science.gov (United States)

    Da Lio, A L; Jones, N F

    1998-01-01

    Microsurgical free tissue transfer is currently associated with very high success rates and few complications. While interposition vein grafting is clearly an important adjunct to the microsurgeon's armamentarium, it has been associated with higher free flap/replantation failures and complication rates. With appropriate flap planning and surgical techniques, the need for interposition vein grafting should be quite infrequent and hopefully avoided if at all possible. Nevertheless, when necessary, the vein graft remains the gold standard, with virtually all alternative interposition grafts demonstrating lower patency rates. One of the more promising areas of research is the concept of genetic manipulation of the endothelial cell via molecular biological techniques. It is likely that in the near future this may become a clinical reality, not only improving the patency of microsurgical anastomoses and interposition vein grafts, but quite possibly altering the target organ functionally as well.

  13. Influence of Material Properties on Rate of Resorption of Two Bone Graft Materials after Sinus Lift Using Radiographic Assessment

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    Fawzi Riachi

    2012-01-01

    Full Text Available Purpose. The aim of this study was to investigate the influence of chemical and physical properties of two graft materials on the rate of resorption. Materials and Methods. Direct sinus graft procedure was performed on 22 patients intended for implant placement. Two types of graft materials were used (Bio-Oss and Cerabone and after 8 months healing time the implants were inserted. Radiographic assessment was performed over the period of four years. Particle size, rate of calcium release, and size and type of crystal structure of each graft were evaluated. Results. The average particle size of Bio-Oss (1 mm was much smaller compared to Cerabone (2.7 mm. The amount of calcium release due to dissolution of material in water was much higher for Bio-oss compared to Cerabone. X-ray image analysis revealed that Bio-Oss demonstrated significantly higher volumetric loss (33.4 ± 3.1% of initial graft size compared to Cerabone (23.4 ± 3.6%. The greatest amount of vertical loss of graft material volume was observed after one year of surgery. Conclusion. The chemical and physical properties of bone graft material significantly influence resorption rate of bone graft materials used for sinus augmentation.

  14. A Prospective and Controlled Clinical Trial on Stromal Vascular Fraction Enriched Fat Grafts in Secondary Breast Reconstruction

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    L. A. L. Tissiani

    2016-01-01

    Full Text Available Background. Fat grafting is a tremendous tool in secondary breast reconstruction. Stromal vascular fraction (SVF enriched fat grafts have been presenting promising results regarding volume maintenance. Methods. We developed a method that produces a superior SVF enrichment rate (2 : 1 in the operating theatre. This prospective and controlled trial analyzed quantitatively and qualitatively fat grafts with (stem cells group, SG and without (control group, CG SVF enrichment in secondary breast reconstruction, through MRI-based volumetry, immunophenotyping, and cell counting. Also, patient satisfaction, aesthetic outcomes, and complications were analyzed. Results. Volumetric persistence in the SG was 78,9% and 51,4% in the CG; however it did not reach statistical significant difference. CD90 was the only marker highly expressed in the SG and showed a positive correlation with volumetric persistence (r=0.651, p=0.03. Fat necrosis occurred in 4 patients in the SG and in none in the CG. Patients in the CG showed a trend to be more satisfied. Considering aesthetics, both groups presented improvements. No locoregional recurrences were observed. Conclusions. Results are encouraging despite the fact that SVF enrichment in a higher supplementation rate did not improve, with statistical significance, fat graft volumetric persistence. Enriched fat grafts have proven to be safe in a 3-year follow-up.

  15. Optimal endothelialisation of a new compliant poly(carbonate-urea)urethane vascular graft with effect of physiological shear stress.

    Science.gov (United States)

    Salacinski, H J; Tai, N R; Punshon, G; Giudiceandrea, A; Hamilton, G; Seifalian, A M

    2000-10-01

    to define the optimal seeding conditions of a new stress free poly(carbonate-urea)urethane (CPU) graft with compliance similar to that of human artery with honeycomb structure engineered during the manufacturing process to enhance adhesion and growth of endothelial cells. (111)Indium-oxine radiolabeled human umbilical vein endothelial cells (HUVEC) were seeded onto CPU grafts at (a) concentrations from 2-24x10(5)cells/cm(2)and (b) incubated for 0.5, 1, 2, 4 and 6 h. Following incubation, graft segments were subjected to three washing/gamma counting procedures and scanning electron microscopy (SEM). Cell viability was measured using a modified Alamar blue(TM)assay. To test physiological retention a pulsatile flow phantom was used to subject optimally seeded (16x10(5), 4 h) CPU grafts to arterial shear stress for 6 h with real time acquisition of scintigraphic images of seeded grafts using a nuclear medicine gamma camera system. the seeding efficiency of 54+/-13% post three washes was achieved using 16x10(5)cells/cm(2). Similarly in SEM micrographs a seeding density of 16x10(5)cells/cm(2)resulted in a confluent monolayer. Seeded CPU segments incubated for 4 h exhibited significantly higher resistance to wash-off than segments incubated for 30 min (p <0.05). Exposure of seeded grafts to pulsatile shear stress resulted in some cell loss with 67+/-3% of cells adherent following 6 h of perfusion with ongoing metabolic activity. Thus, optimal conditions were 16x10(5)cells/cm(2)at 4 h. the optimal seeding conditions have been defined for "tissue-engineered" vascular graft which allow complete endothelialisation and high cell-to-substrate strength that resists hydrodynamic stress. Copyright 2000 Harcourt Publishers Ltd.

  16. Grafting materials for alveolar cleft reconstruction: a systematic review and best-evidence synthesis.

    Science.gov (United States)

    Wu, C; Pan, W; Feng, C; Su, Z; Duan, Z; Zheng, Q; Hua, C; Li, C

    2018-03-01

    The purpose of this study was to compare the efficacy of alveolar bone reconstruction for alveolar cleft patients performed with the traditional iliac graft or alternative/supplementary bone grafting materials. Electronic databases, relevant journals, and reference lists of the included studies were searched to the end of June 2016. A best-evidence synthesis was performed to draw conclusions. A total of 38 studies were included, which provided 25 pieces of evidence: seven of moderate evidence and 18 of insufficient evidence. The seven pieces of moderate evidence indicated that (1) bone morphogenetic protein 2 bound to absorbable collagen sponge shares similar cleft repair efficacy to the iliac graft; (2) covering the iliac graft with an acellular dermis matrix membrane may increase bone retention for unilateral cleft patients; (3) mixing iliac graft with platelet-rich plasma may increase bone retention for skeletally mature patients, but (4) does not achieve the same result for younger patients; and compared with the iliac graft, (5) the mandible graft is more effective, whereas (6) the cranium graft and (7) rib graft are less effective for alveolar cleft reconstruction. The efficacy of the remaining grafting materials was supported by insufficient evidence. More well-designed controlled studies are needed to ascertain the long-term clinical results of alveolar cleft reconstruction. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  17. Renal Transplantation as a Platform for Teaching Residents Open Vascular Surgical Techniques: Effects on Early Graft Function.

    Science.gov (United States)

    Grodstein, Elliot I; Little, Christopher; Molmenti, Ernesto P; Mezrich, Joshua D

    2018-01-17

    Over the past decade, increases in vascular fellowships and the use of endovascular technology have decreased the general surgery residents' exposure to open vascular surgery. We sought to elucidate whether renal transplant is a safe way to teach general surgery residents the essential tenants of vascular surgery without adversely affecting early patient outcomes. All solitary, adult deceased donor kidney transplants performed at the University of Wisconsin from 2011 through 2016 were identified and divided into a resident-assist (RA) and fellow-assist cohorts (FA). DGF, defined by the requirement of dialysis within 1 week of transplant, was the primary outcome. Early graft survival and postoperative complications were considered the secondary endpoints. Of the 774 total cases, there were 228 (29.5%) in the RA cohort and 546 (70.5%) in the FA cohort. The RA and FA cohorts had comparable characteristics, except for a nonclinically significant difference in mean donor creatinine (0.96 vs 0.88mg/dL, p = 0.03). RA cases had a similar DGF rate compared to FA cases (25% vs 26%, p = 0.93). Additionally, there was no difference in 2-year graft survival (93.7% vs 95.5%, p = 0.38), nor the rates of graft thromboses (0.4% vs 0.7%, p = 0.65), incisional hernias (0.9% vs 1.8%, p = 0.35), and ureteral strictures (2.2% vs 1.6%, p = 0.55) between the 2 cohorts. Resident involvement in renal transplantation has no effect on DGF and early allograft function. Though the procedural involvement of each resident in a case is variable, it seems to be a safe way to teach retroperitoneal vascular exposure and anastomotic techniques. Copyright © 2018. Published by Elsevier Inc.

  18. Alveolar ridge augmentation: comparison of two socket graft materials in implant cases.

    Science.gov (United States)

    Tolstunov, Len; Chi, Jibin

    2011-01-01

    With the variety of bone grafting materials available and their use around both natural teeth and dental implants, clinicians need to understand not only basic bone biology but also characteristics of different bone grafting materials to make a proper choice when selecting a material for alveolar bone augmentation and implant treatment. The grafting materials used in the maxillofacial region include autogenous bone, allografts, xenografts, alloplastic or synthetic products, and composite grafts (combination of different materials). This case report describes two frequenly used bone graft materials for socket preservation immediately after extraction: Puros® (Zimmer Dental Inc, www.zimmerdental.com) (allogeneic) and Bio-Oss®(Osteohealth Co, www.osteohealth.comwww.osteohealth.com) (xenogeneic). In the case presented, the authors perform biologic, clinical, radiologic, and histologic analysis of the two grafting materials by placing them side-by-side in the same patient during implant reconstruction. Implant-related phases of bone augmentation are proposed, and an overview of bone grafting materials, specifically Bio-Oss and Puros, is presented.

  19. Dacron® vs. PTFE as bypass materials in peripheral vascular surgery – systematic review and meta-analysis

    Directory of Open Access Journals (Sweden)

    Eidt Daniela

    2008-12-01

    Full Text Available Abstract Background In peripheral vascular bypass surgery different synthetic materials are available for bypass grafting. It is unclear which of the two commonly used materials, polytetrafluoroethylene (PTFE or polyester (Dacron® grafts, is to be preferred. Thus, the aim of this meta-analysis and systematic review was to compare the effectiveness of these two prosthetic bypass materials (Dacron® and PTFE. Methods We performed a systematic literature search in MEDLINE, Cochrane-Library – CENTRAL, EMBASE and other databases for relevant publications in English and German published between 1999 and 2008. Only randomized controlled trials were considered for inclusion. We assessed the methodological quality by means of standardized checklists. Primary patency was used as the main endpoint. Random-effect meta-analysis as well as pooling data in life table format was performed to combine study results. Results Nine randomized controlled trials (RCT were included. Two trials showed statistically significant differences in primary patency, one favouring Dacron® and one favouring PTFE grafts, while 7 trials did not show statistically significant differences between the two materials. Meta-analysis on the comparison of PTFE vs. Dacron® grafts yielded no differences with regard to primary patency rates (hazard ratio 1.04 (95% confidence interval [0.85;1.28], no significant heterogeneity (p = 0.32, I2 = 14%. Similarly, there were no significant differences with regard to secondary patency rates. Conclusion Systematic evaluation and meta-analysis of randomized controlled trials comparing Dacron® and PTFE as bypass materials for peripheral vascular surgery showed no evidence of an advantage of one synthetic material over the other.

  20. The use of prosthetic grafts in complex military vascular trauma: a limb salvage strategy for patients with severely limited autologous conduit.

    Science.gov (United States)

    Vertrees, Amy; Fox, Charles J; Quan, Reagan W; Cox, Mitchell W; Adams, Eric D; Gillespie, David L

    2009-04-01

    The use of prosthetic grafts for reconstruction of military vascular trauma has been consistently discouraged. In the current conflict, however, the signature wound involves multiple extremities with significant loss of soft tissue and potential autogenous venous conduits. We reviewed the experience with the use of prosthetic grafts for the treatment of vascular injuries sustained during recent conflicts in Iraq and Afghanistan. Trauma registry records with combat-related vascular injuries repaired using prosthetic grafts were retrospectively reviewed from March 2003 to April 2006. Data collected included age, gender, mechanism of injury, vessel injured, conduit, graft patency, complications, including amputation and eventual outcome of repair. Prosthetic grafts were placed in 14 of 95 (15%) patients undergoing extremity bypass for vascular injuries. Patients were men with an average age of 25 years (range, 19-39 years). All prosthetic grafts in this series were made of polytetrafluoroethylene. Mechanism of injury included blast (n = 6), gunshot wounds (n = 6), and blunt trauma (n = 2), resulting in prosthetic repair of injuries to the superficial femoral (n = 8), brachial (n = 3), common carotid (n = 1), subclavian (n = 1), and axillary (n = 1) arteries. Mean evacuation time from injury to stateside arrival was 7 days (range, 3-9 days). Twelve grafts were placed initially at the time of injury, and two after vein graft blow out with secondary hemorrhage. The mean follow-up period was 427 days (range, 49-1,285 days). Seventy-nine percent of prosthetic grafts stayed patent in the short term, allowing patient stabilization, transport to a stateside facility, and elective revascularization with the remaining autologous vein graft. Three prosthetic grafts were replaced urgently for thrombosis. The remaining seven grafts were replaced electively for severe stenosis (3) or exposure (4) with presumed infection. There were no prosthetic graft blow outs or deaths in this

  1. Use of ultrasound debridement as an adjunctive tool for treating infected prosthetic vascular grafts in the lower extremities.

    Science.gov (United States)

    Carmo, Michele; Mazzaccaro, Daniela; Barbetta, Iacopo; Settembrini, Alberto M; Roveri, Sergio; Fumagalli, Miriam; Tassinari, Luca; Settembrini, Piergiorgio G

    2015-04-01

    To evaluate the role of an ultrasound (US) debridement system to treat conservatively patients with poor medical conditions who presented with infection of a prosthetic vascular graft in the lower extremities. Data of all patients who underwent debridement of the grafts and/or surrounding tissue using an ultrasonic generator (Genera, Italia Medica, Milan, Italy) were recorded and retrospectively reviewed. Based on cultures, patients received specific antibiotic therapy. Partial graft removal, sartorius muscle flap rotation, or negative pressure wound treatment (NPWT) was selectively used. Early and late morbidity and mortality and recurrence were analyzed. Thirteen patients (median age, 72 years; range, 57-92 years; 8 men) were treated (12 Szilagyi grade III and 1 grade II infections) with US debridement without removing the graft (8 cases) or with partial excision and "in situ" reconstruction with a silver prosthetic graft (5 cases). Sartorius flap rotation was associated in 6 and NPWT in 1 case. One patient died perioperatively because of pulmonary edema because of sepsis secondary to treatment failure. Estimated freedom from reinfection was 90.9 ± 9% at 6 months and 77.9 ± 14% at 1 and 2 years. Estimated limb survival was 78.7 ± 13% at 6 months, 65.6 ± 16% at 1 year, and 52.5 ± 18% at 2 years. US debridement proved to be a valuable aid in the treatment of patients with infected grafts and poor medical conditions. Used in conjunction with antibiotics, it allowed us to be more conservative without compromising the chance of success. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Clinical evaluation of ridge augmentation using autogenous tooth bone graft material: case series study.

    Science.gov (United States)

    Lee, Ji-Young; Kim, Young-Kyun; Yi, Yang-Jin; Choi, Joon-Ho

    2013-08-01

    Interest in bone graft material has increased with regard to restoration in cases of bone defect around the implant. Autogenous tooth bone graft material was developed and commercialized in 2008. In this study, we evaluated the results of vertical and horizontal ridge augmentation with autogenous tooth bone graft material. This study targeted patients who had vertical or horizontal ridge augmentation using AutoBT from March 2009 to April 2010. We evaluated the age and gender of the subject patients, implant stability, adjunctive surgery, additional bone graft material and barrier membrane, post-operative complication, implant survival rate, and crestal bone loss. We performed vertical and horizontal ridge augmentation using powder- or block-type autogenous tooth bone graft material, and implant placement was performed on nine patients (male: 7, female: 2). The average age of patients was 49.88±12.98 years, and the post-operative follow-up period was 35±5.31 months. Post-operative complications included wound dehiscence (one case), hematoma (one case), and implant osseointegration failure (one case; survival rate: 96%); however, there were no complications related to bone graft material, such as infection. Average marginal bone loss after one-year loading was 0.12±0.19 mm. Therefore, excellent clinical results can be said to have been obtained. Excellent clinical results can be said to have been obtained with vertical and horizontal ridge augmentation using autogenous tooth bone graft material.

  3. Tailored Double-Barrel Bypass Surgery Using an Occipital Artery Graft for Unstable Intracranial Vascular Occlusive Disease.

    Science.gov (United States)

    Chung, Yeongu; Lee, Sung Ho; Ryu, Jiwook; Kim, Johnho; Chung, Sang Bong; Choi, Seok Keun

    2017-05-01

    This report describes the need for a tailored approach for intracranial vascular occlusive disease and introduces the usefulness of the OA as a donor artery for interposition graft. A 65-year-old male patient suffered from repeated transient ischemic attack (TIA). Imaging studies revealed complete occlusion of the proximal left side of the internal carotid artery (ICA) and multiple infarction in the watershed zone. We planned superficial temporal artery-middle cerebral artery (STA-MCA) bypass to restore cerebral blood flow and to prevent the progression of infarction. However, the parietal branch of the STA was too small in diameter and not suitable as a single donor for the bypass in order to supply sufficient blood flow. Moreover, the frontal branch of the STA had collateral channels through the periorbital anastomosis into the cerebral cortex that could result in infarction during clamping for anastomosis. We determined that tailored treatment planning was necessary for successful revascularization under these conditions. Thus, we performed a bypass between the parietal branch of the STA and a cortical branch of the MCA as an "insurance bypass." Then we performed another bypass between the frontal branch of the STA and a cortical branch of the MCA using an ipsilateral occipital artery (OA) interposition graft. The patient had no perioperative complications, and postoperative imaging confirmed the restoration of cerebral blood flow. When end-to-side anastomosis in single-branch bypass is not appropriate for cerebral revascularization, a tailored double-barrel "insurance bypass" with an OA interposed graft could be a good alternative treatment modality. In addition, an OA interposition graft is a useful option for double-barrel bypass surgery in such cases of intracranial vascular occlusive disease. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. The end stage of dialysis access: femoral graft or HeRO vascular access device.

    Science.gov (United States)

    Kudlaty, Elizabeth A; Pan, Jeanne; Allemang, Matthew T; Kendrick, Daniel E; Kashyap, Vikram S; Wong, Virginia L

    2015-01-01

    Maintaining and establishing vascular access in end-stage renal disease (ESRD) patients is complicated when they are poor candidates for traditional upper extremity access. Our objective was to compare our experience with 2 alternative dialysis accesses, the femoral arteriovenous graft (fAVG) and the Hemodialysis Reliable Outflow (HeRO), in patients with limited remaining options. A single institution, retrospective review of ESRD patients with fAVG or HeRO placed between May 2009 and February 2013 was performed. Adult patients were selected by reviewing all arteriovenous grafts placed at a single institution. Patient demographics, medical history, access characteristics, and outcomes were recorded from both institutional and dialysis center databases. Data were evaluated using Fisher's exact test, unpaired t-test for continuous variables, log-rank test, and univariate analysis. A total of 56 accesses in 43 unique patients met these criteria: 35 fAVG and 21 HeRO; with 1 HeRO patient lost immediately to follow-up. Clinical variables were similar except the HeRO group had more diabetic patients (60% HeRO, 22.9% fAVG; P = 0.01). The average number of years on hemodialysis was 7.0 ± 1.0 for fAVG and 5.7 ± 0.9 for HeRO (P = 0.41). Primary patency was 40.5%, 18.7%, and 14.9% for fAVG and 29.0%, 29.0%, and 0% for HeRO at 6 months, 12 months, and 2 years (P = 0.67), respectively. Assisted primary patency was also similar, with 43.8%, 29.4%, and 13.8% for fAVG and 34.8%, 34.8%, and 17.4% for HeRO at 6 months, 12 months, and 2 years (P = 0.81), respectively. Secondary patency was 62.6%, 50.6%, 19.3% for fAVG and 68.0%, 53.5%, 38.3% for HeRO at 6 months, 12 months, and 2 years (P = 0.69), respectively. Average number of interventions to maintain patency for fAVG was 1.1 ± 1.47 and 1.65 ± 2.52 for HeRO (P = 0.35). Infectious complications occurred in 29% of fAVG and 15% of HeRO (P = 0.33). Patients who received either fAVG or HeRO experience poor access patency. ESRD

  5. [Resection of an aneurysmal bone cyst in the proximal humerus with a non-vascularized fibular graft. Case report].

    Science.gov (United States)

    Lima-Ramírez, P G; Chavarría-Jacinto, J; Martínez-Asención, P; Montiel-Jarquín, A J; Barragán-Hervella, R G; Salvatori-Rubí, J J; Domínguez-Cid, M I

    2015-01-01

    An aneurysmal bone cyst is a benign lesion involving the marrow of long bones; it accounts for 6% of primary bone lesions and may occur as a secondary lesion with other benign or malignant bone tumors. We describe herein the case of a seven year-old female with an aneurysmal bone cyst which was diagnosed clinically, radiographically and with a CAT scan, and confirmed with histopathology. Resection was performed using the eggshell technique and a non-vascularized left fibular bone graft. The patient did well up to the fourth postoperative year, which is consistent with what has been reported in world literature.

  6. Risk factors and outcomes for nosocomial infection after prosthetic vascular grafts.

    Science.gov (United States)

    Fariñas, María Carmen; Campo, Ana; Duran, Raquel; Sarralde, José Aurelio; Nistal, Juan Francisco; Gutiérrez-Díez, José Francisco; Fariñas-Álvarez, Concepción

    2017-11-01

    The objective of this study was to determine risk factors for nosocomial infections (NIs) and predictors of mortality in patients with prosthetic vascular grafts (PVGs). This was a prospective cohort study of all consecutive patients who underwent PVG of the abdominal aorta with or without iliac-femoral involvement and peripheral PVG from April 2008 to August 2009 at a university hospital. Patients younger than 15 years and those with severe immunodeficiency were excluded. The follow-up period was until 3 years after surgery or until death. There were 261 patients included; 230 (88.12%) were male, and the mean age was 67.57 (standard deviation, 10.82) years. The reason for operation was aortic aneurysm in 49 (18.77%) patients or lower limb arteriopathy in 212 (81.23%) patients. NIs occurred in 71 (27.20%) patients. Of these, 42 were surgical site infections (SSIs), of which 61.9% occurred in the lower extremities (14 superficial, 10 deep, and 2 PVG infections) and 38.1% in the abdomen (7 superficial, 7 deep, and 2 PVG infections); 15 were respiratory tract infections; and 15 were urinary tract infections. Active lower extremity skin and soft tissue infection (SSTI) at the time of surgery was a significant predictor of NI for both types of PVG (abdominal aortic PVG: adjusted odds ratio [OR], 12.6; 95% confidence interval [CI], 1.15-138.19; peripheral PVG: adjusted OR, 2.43; 95% CI, 1.08-5.47). Other independent predictors of NI were mechanical ventilation (adjusted OR, 55.96; 95% CI, 3.9-802.39) for abdominal aortic PVG and low hemoglobin levels on admission (adjusted OR, 0.84; 95% CI, 0.71-0.99) and emergent surgery (adjusted OR, 4.39; 95% CI, 1.51-12.74) for peripheral PVG. The in-hospital mortality rate was 1.92%. The probability of surviving the first month was 0.96, and significant predictors of mortality were active lower extremity SSTI (adjusted risk ratio [RR], 12.07; 95% CI, 1.04-154.75), high postsurgical glucose levels (adjusted RR, 1.02; 95% CI, 1

  7. Vascular Biocompatibility of a Triple Layered Self Expanding Stent-Graft in a Dog Mode

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Jae Ik; Won, Je Hwan; Jang, Eun Ho; Lee, Sung Yeong; Ko, Kwang Tae [Dept. of Radiology, Ajou University School of Medicine, Suwon (Korea, Republic of); Jin, Bo Hwan [Medical Science Research Center, Ajou University School of Medicine, Suwon (Korea, Republic of); Lee, June Woo [Dept. of Radiology, Busan National University College of Medicine, Busan (Korea, Republic of)

    2012-02-15

    To evaluate performance and biocompatibility of a newly designed self-expanding stent graft, which consisted of two nitinol stents and an intervening expanded polytetrafluoroethylene membrane in a dog artery model. Twelve stent grafts were placed in the aorta of 6 dogs (beagle, mean body weight 11 kg) for 4 weeks (n = 4) and 12 weeks (n = 8). Luminal diameters were measured for each segment (the proximal bare, the middle graft, the distal bare) by angiographies after implantation and follow up periods. Percent luminal stenosis based on angiographies, histomorphometric, histologic, and scanning electron microscopic analyses of each segments were performed. Blood flow through the stent grafts was good after implantation and during the follow up period, without thrombotic occlusion or stent graft migration. The mean percent luminal stenosis of the proximal bare, the middle grafted and the distal bare segments after 12 weeks were 13.5%, 3.9%, 9.6% retrospectively. The mean neointimal areas of the middle grafted segment were 4.39 mm{sup 2} (4 week) and 4.92 mm{sup 2} (12 week). Mature endothelialization was evident in over 70% of the area of the stented artery after 4 weeks and in over 90% after 12 weeks. The stent graft was well placed in the attempted area without migration. During the 12-week-follow up period, it showed a good patency without thrombotic occlusion or significant in-stent luminal stenosis. Endothelialization was rapid and nearly complete. Neointima was thin and smooth on the middle graft segment and thicker and irregular on the bare segments.

  8. Clinical application of platelet-rich fibrin as the sole grafting material in periodontal intrabony defects

    Directory of Open Access Journals (Sweden)

    Yu-Chao Chang

    2011-09-01

    Conclusions: From a clinical and radiologic point of view at 6 months after surgery, the use of PRF as the sole grafting material seems to be an effective modality of regenerative treatment for periodontal intrabony defects.

  9. Obtaining of Grafted Planting Material at Some Romanian Tomatoes

    Directory of Open Access Journals (Sweden)

    Madalina Doltu

    2016-11-01

    Full Text Available The tomatoes have highest share in Romanian crops from protected spaces (greenhouses, solariums. The grafting is an agronomical technique that induces or improves some qualities of the tomato cultivars (resistance to soil diseases and pests, resistance to abiotic factors, quantity and quality of fruit production. The research was aimed the establishing of the technological stages for producing of scion and rootstock seedlings from L. esculentum species, to obtain compatible phenotype when is grafted. The observations of this research were conducted on Department of Horticultural Cultures in Protected Spaces from Horting Institute Bucharest. The experience was carry out on a cultivar collection consisting from L. esculentum plants: scions (‘Siriana’–F1 hybrid and ‘Buzău 1600’– variety, creations from the germplasm bank of Research and Development Station for Vegetable Growing Buzău Romania (VDRS Buzău and rootstock (‘Groundforce’–F1 hybrid. The plant diameters were correlated for a grafting by the annexation method, cutting at 45 degrees. The grafting was performed successfully. The technological steps have achieved phenotypic compatibility of the symbiotes when was the grafting by annexation. The technology for producing of scion and rootstock seedlings at these Romanian tomatoes (‘Siriana’ and ‘Buzău’ 1600 was established for the crops in protected spaces in south area of Romania.

  10. Vascular Tissue Engineering: Effects of Integrating Collagen into a PCL Based Nanofiber Material

    Directory of Open Access Journals (Sweden)

    Ulf Bertram

    2017-01-01

    Full Text Available The engineering of vascular grafts is a growing field in regenerative medicine. Although numerous attempts have been made, the current vascular grafts made of polyurethane (PU, Dacron®, or Teflon® still display unsatisfying results. Electrospinning of biopolymers and native proteins has been in the focus of research to imitate the extracellular matrix (ECM of vessels to produce a small caliber, off-the-shelf tissue engineered vascular graft (TEVG as a substitute for poorly performing PU, Dacron, or Teflon prostheses. Blended poly-ε-caprolactone (PCL/collagen grafts have shown promising results regarding biomechanical and cell supporting features. In order to find a suitable PCL/collagen blend, we fabricated plane electrospun PCL scaffolds using various collagen type I concentrations ranging from 5% to 75%. We analyzed biocompatibility and morphological aspects in vitro. Our results show beneficial features of collagen I integration regarding cell viability and functionality, but also adverse effects like the loss of a confluent monolayer at high concentrations of collagen. Furthermore, electrospun PCL scaffolds containing 25% collagen I seem to be ideal for engineering vascular grafts.

  11. Histological comparison of an allograft, a xenograft and alloplastic graft as bone substitute materials

    Directory of Open Access Journals (Sweden)

    C.E. Nappe

    2016-11-01

    Full Text Available Aim An allograft, a xenograft and an alloplastic graft, associated to sinus lift or ridge preservation procedures were histologically studied to evaluate their characteristics and to obtain the percentages of bone and remaining graft particles. This may help the clinician to determine, form the histological point of view, if they are viable alternatives to the use of autograft in bone regeneration procedures. Materials and methods Twenty-five samples from 18 subjects were histologically evaluated with respect to newly formed bone and remaining graft particles percentage. Results The three studied grafting materials presented adequate osteoconduction characteristics. Differences in newly formed bone percentage were found between the allograft and the xenograft, whereas no differences were found between the allograft and the alloplastic graft or the xenograft and the alloplastic graft. There were no significant differences in the percentage of residual particles amongst the different types of graft. Conclusions All studied bone substitute materials showed good characteristics for their use in bone regeneration therapies.

  12. Treatment of hemodialysis vascular access arteriovenous graft failure by percutaneous intervention

    NARCIS (Netherlands)

    Planken, Robrecht Nils; van Kesteren, Floortje; Reekers, Jim A.

    2014-01-01

    A patent vascular access is the lifeline of end-stage renal disease patients depending on hemodialysis treatment. Once a functioning vascular access has been established, maintaining its patency is of utmost importance. During the last decades percutaneous techniques became increasingly important

  13. In vitro and in vivo evaluation of blood coagulation activation of polyvinyl alcohol hydrogel plus dextran-based vascular grafts.

    Science.gov (United States)

    Alexandre, Nuno; Costa, Elísio; Coimbra, Susana; Silva, Alice; Lopes, Ascensão; Rodrigues, Miguel; Santos, Marta; Maurício, Ana Colette; Santos, José Domingos; Luís, Ana Lúcia

    2015-04-01

    Polyvinyl alcohol hydrogel (PVA) is a water-soluble synthetic polymer that is commonly used in biomedical applications including vascular grafting. It was argued that the copolymerization of PVA with dextran (Dx) can result in improvement of blood-biomaterial interactions. The focus of this experimental study was to assess that interaction through an in vivo and in vitro evaluation of the coagulation system activation. The thrombogenicity of the copolymer was determined by quantification of platelet adhesion through the lactate dehydrogenase assay, determination of whole blood clotting time, and by quantification of platelet activation by flow cytometry. The thrombin-antithrombin complex blood levels were also determined. The obtained results for the in vitro assays suggested a non-thrombogenic profile for PVA/Dx. Additionally in vivo coagulation and hematological parameters were determined in an animal model after PVA/Dx vascular graft implantation. For coagulation homeostasis assessment, the intrinsic and extrinsic pathway's activation was determined by measuring prothrombin time (PT) and activated partial thromboplastin time (aPTT). Other markers of coagulation and inflammation activation including d-dimers, interleukin-6, and C-reactive protein were also assessed. The PVA/Dx copolymer tended to inhibit platelet adhesion/activation process and the contact activation process for coagulation. These results were also confirmed with the in vivo experiments where the measurements for APTT, interleukin-6, and C-reactive protein parameters were normal considering the species normal range of values. The response to those events is an indicator of the in vitro and in vivo hemocompatibility of PVA/Dx and it allows us to select this biomaterial for further preclinical trials in vascular reconstruction. © 2014 Wiley Periodicals, Inc.

  14. Contact-free monitoring of vessel graft stiffness - proof of concept as a tool for vascular tissue engineering.

    Science.gov (United States)

    Hoenicka, Markus; Kaspar, Marcel; Schmid, Christof; Liebold, Andreas; Schrammel, Siegfried

    2017-10-01

    Tissue-engineered vessel grafts have to mimic the biomechanical properties of native blood vessels. Manufacturing processes often condition grafts to adapt them to the target flow conditions. Graft stiffness is influenced by material properties and dimensions and determines graft compliance. This proof-of-concept study evaluated a contact-free method to monitor biomechanical properties without compromising sterility. Forced vibration response analysis was performed on human umbilical vein (HUV) segments mounted in a buffer-filled tubing system. A linear motor and a dynamic signal analyser were used to excite the fluid by white noise (0-200 Hz). Vein responses were read out by laser triangulation and analysed by fast Fourier transformation. Modal analysis was performed by monitoring multiple positions of the vessel surface. As an inverse model of graft stiffening during conditioning, HUV were digested proteolytically, and the course of natural frequencies (NFs) was monitored over 120 min. Human umbilical vein showed up to five modes with NFs in the range of 5-100 Hz. The first natural frequencies of HUV did not alter over time while incubated in buffer (p = 0.555), whereas both collagenase (-35%, p = 0.0061) and elastase (-45%, p < 0.001) treatments caused significant decreases of NF within 120 min. Decellularized HUV showed similar results, indicating that changes of the extracellular matrix were responsible for the observed shift in NF. Performing vibration response analysis on vessel grafts is feasible without compromising sterility or integrity of the samples. This technique allows direct measurement of stiffness as an important biomechanical property, obviating the need to monitor surrogate parameters. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Maxillary Sinus Membrane Elevation With Simultaneous Installation of Implants Without the Use of a Graft Material

    DEFF Research Database (Denmark)

    Starch-Jensen, Thomas; Schou, Søren

    2017-01-01

    OBJECTIVE: To compare implant treatment outcome after maxillary sinus membrane elevation with simultaneous installation of implants with or without the use of graft material applying the lateral window technique. MATERIALS AND METHODS: MEDLINE/PubMed, Cochrane Library, and Embase search in combin......OBJECTIVE: To compare implant treatment outcome after maxillary sinus membrane elevation with simultaneous installation of implants with or without the use of graft material applying the lateral window technique. MATERIALS AND METHODS: MEDLINE/PubMed, Cochrane Library, and Embase search...

  16. Stimulation of vascularization of a subcutaneous scaffold applicable for pancreatic islet-transplantation enhances immediate post-transplant islet graft function but not long-term normoglycemia

    OpenAIRE

    Smink, Alexandra M.; Shiri, Li; Swart, Daniël H; Hertsig, Don T; de Haan, Bart J.; Kamps, Jan A A M; Schwab, Leendert; van Apeldoorn, Aart A.; de Koning, Eelco; Faas, Marijke M.; Lakey, Jonathan R.T.; Vos, Paul

    2017-01-01

    Abstract The liver as transplantation site for pancreatic islets is associated with significant loss of islets, which can be prevented by grafting in a prevascularized, subcutaneous scaffold. Supporting vascularization of a scaffold to limit the period of ischemia is challenging and was developed here by applying liposomes for controlled release of angiogenic factors. The angiogenic capacity of platelet?derived growth factor, vascular endothelial growth factor, acidic fibroblast growth factor...

  17. Analysis of pressure losses in the hemodialysis graft vascular circuit using finite element analysis.

    Science.gov (United States)

    Beasley, Madison P; Conrad, Steven A

    2007-01-01

    Vascular access complications (stenosis and thrombosis) present the greatest morbidity associated with chronic hemodialysis. Understanding the hemodynamics of the vascular access circuit is essential identify problems. We developed a finite element model based on a previously-reported experimental vascular circuit model, and compared pressure losses at segments within the circuit determined by the finite element model with experimental results and with an analytical model based on the circuit. In most cases the finite element model better predicted the pressure losses than did the analytical model. The finite element model also revealed the complex flow patterns that can occur in hemodialysis vascular access circuits that may explain some of the variance with the analytical model.

  18. Ischemic flap survival improvement by composition-selective fat grafting with novel adipose tissue derived product - stromal vascular fraction gel.

    Science.gov (United States)

    Zhang, Pan; Feng, Jingwei; Liao, Yunjun; Cai, Junrong; Zhou, Tao; Sun, Mingliang; Gao, Jianhua; Gao, Kai

    2017-11-30

    Flap necrosis due to insufficient blood supply is a common postoperative complication in random pattern flaps. Stem cell therapies have emerged as promising biologics for tissue ischemia. A novel fat derived product, stromal vascular fraction gel (SVF-gel), can be prepared with lipoaspirate through simple mechanical processing, removing only the lipid content. SVF-gel enriches adipose-derived stem cells and potentially beneficial for flap necrosis. Nude mice ischemic flaps were treated with human SVF-gel, stromal vascular fraction (SVF) cell suspension or saline (n = 10). They were injected to the flap recipient beds, and necrosis and vascularization was assessed on postoperative day 14. We harvested the necrosis-free distal to evaluated skin healthiness and neovasculogenesis by Masson's trichrome stain and immunofluorescence, etc. Pro-angiogenic factors were assessed with tissue qRT-PCR. Finally, we traced the grafted human tissue with immunofluorescence. SVF-gel-treated flaps have the smallest necrotic zones (22.05% ± 0.0438) compared with the saline controls (53.78% ± 0.1412) or SVF-treated ones (35.54% ± 0.0850, p = 0.039). Numerous functional musculocutaneous perforators were developed around SVF-gel grafts. The SVF-gel-treated skin had the best fat restoration (231.3 ± 48.1 μm) among three groups (F = 10.83, p = 0.0102) while saline-treated flap distal appeared fibrotic. SVF-gel-treated flaps also had ∼43% more CD31 + capillaries (p = 0.0152) with ∼3 folds more gene expression of angiogenic cytokines of VEGF and bFGF (p = 0.0310 and 0.0303, respectively) than saline-treated controls. Furthermore, we found hSVF-gel cells (hGolgi+) had directly engrafted as vessel component (α-smooth muscle actin, α-SMA+) to the flap. Adipose cellular matrix enhanced flap neovascularization partly by direct incorporation, improved flap survival and fat restoration. The composition-selective fat grafting with SVF-gel demonstrated efficacy

  19. Tissue-Engineered Small Diameter Arterial Vascular Grafts from Cell-Free Nanofiber PCL/Chitosan Scaffolds in a Sheep Model.

    Directory of Open Access Journals (Sweden)

    Takuma Fukunishi

    Full Text Available Tissue engineered vascular grafts (TEVGs have the potential to overcome the issues faced by existing small diameter prosthetic grafts by providing a biodegradable scaffold where the patient's own cells can engraft and form functional neotissue. However, applying classical approaches to create arterial TEVGs using slow degrading materials with supraphysiological mechanical properties, typically results in limited host cell infiltration, poor remodeling, stenosis, and calcification. The purpose of this study is to evaluate the feasibility of novel small diameter arterial TEVGs created using fast degrading material. A 1.0mm and 5.0mm diameter TEVGs were fabricated with electrospun polycaprolactone (PCL and chitosan (CS blend nanofibers. The 1.0mm TEVGs were implanted in mice (n = 3 as an unseeded infrarenal abdominal aorta interposition conduit., The 5.0mm TEVGs were implanted in sheep (n = 6 as an unseeded carotid artery (CA interposition conduit. Mice were followed with ultrasound and sacrificed at 6 months. All 1.0mm TEVGs remained patent without evidence of thrombosis or aneurysm formation. Based on small animal outcomes, sheep were followed with ultrasound and sacrificed at 6 months for histological and mechanical analysis. There was no aneurysm formation or calcification in the TEVGs. 4 out of 6 grafts (67% were patent. After 6 months in vivo, 9.1 ± 5.4% remained of the original scaffold. Histological analysis of patent grafts demonstrated deposition of extracellular matrix constituents including elastin and collagen production, as well as endothelialization and organized contractile smooth muscle cells, similar to that of native CA. The mechanical properties of TEVGs were comparable to native CA. There was a significant positive correlation between TEVG wall thickness and CD68+ macrophage infiltration into the scaffold (R2 = 0.95, p = 0.001. The fast degradation of CS in our novel TEVG promoted excellent cellular infiltration and neotissue

  20. Effects of bone graft materials on the microhardness of mineral trioxide aggregate.

    Science.gov (United States)

    Sato, Erick Y; Svec, Timothy; Whitten, Brian; Sedgley, Christine M

    2012-05-01

    Large through-and-through lesions have been reported to heal faster and better when filled with bone graft material at the time of an apicoectomy. It is unknown what effect these have on retrograde filling materials such as white mineral trioxide aggregate (WMTA). In this study, the null hypothesis was tested that the presence of bone graft materials does not affect the microhardness of WMTA. Freshly mixed WMTA was condensed into acrylic cylinders and preincubated aerobically at 37°C for 1 hour. Cylinders were immersed in simulated body fluid in close proximity to graft materials: xenograft (Bio-Oss, n = 60), freeze-dried bone allograft (MinerOss, n = 60), demineralized freeze-dried bone allograft (OraGraft, n = 40), and allograft (Puros, n = 60). Knoop microhardness of half the samples in each group was evaluated after 2 weeks of incubation and the remainder at 4 weeks. The values for each group were then compared with 2-way analysis of variance and Bonferroni post hoc tests. WMTA microhardness values for Bio-Oss, MinerOss, and Puros groups were lower than those for OraGraft and control groups regardless of incubation period (P Microhardness values were higher at 4 weeks compared with 2 weeks for MinerOss (P materials appear to have a differential effect on the microhardness of WMTA. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  1. Surgeons' performance determining the amount of graft material for sinus floor augmentation using tomography

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Adriana Dibo; Peixoto, Guilherme Alvares; Aguiar, Marcelo Freitas; Camargo, Gabriela Alessandra Cruz Galhardo; Homs, Nicolas, E-mail: adrianadibo@gmail.com [Universidade Federal Fluminense (UFF), Nova Friburgo, RJ, (Brazil)

    2017-05-15

    This study aimed to assess the performance of surgeons in determining the amount of graft material required for maxillary sinus floor augmentation in a preoperative analysis using cone-beam computed tomography images. A convenience sample of 10 retrospective CBCT exams (i-CAT®) was selected. Scans of the posterior maxilla area with an absence of at least one tooth and residual alveolar bone with an up to 5 mm height were used. Templates (n=20) contained images of representative cross-sections in multiplanar view. Ten expert surgeons voluntarily participated as appraisers of the templates for grafting surgical planning of a 10 mm long implant. Appraisers could choose a better amount of graft material using scores: 0) when considered grafting unnecessary, 1) for 0.25 g in graft material, 2) for 0.50 g, 3) for 1.00 g and 4) for 1.50 g or more. Reliability of the response pattern was analyzed using Cronbach's α. Wilcoxon and Mann-Whitney tests were performed to compare scores. Regression analysis was performed to evaluate whether the volume of sinuses (mm{sup 3}) influenced the choose of scores. In the reliability analysis, all values were low and the score distribution was independent of the volume of the maxillary sinuses (p>0.05), which did not influence choosing the amount of graft material. Surgeons were unreliable to determine the best amount of graft material for the maxillary sinus floor augmentation using only CBCT images. Surgeons require auxiliary diagnostic tools to measure the volume associated to CBCT exams in order to perform better. (author)

  2. Stimulation of vascularization of a subcutaneous scaffold applicable for pancreatic islet-transplantation enhances immediate post-transplant islet graft function but not long-term normoglycemia

    NARCIS (Netherlands)

    Smink, Alexandra M; Li, Shiri; Swart, Daniël H; Hertsig, Don T; de Haan, Bart J; Kamps, Jan A A M; Schwab, Leendert; van Apeldoorn, Aart; de Koning, Eelco; Faas, Marijke M; Lakey, Jonathan R T; de Vos, Paul

    The liver as transplantation site for pancreatic islets is associated with significant loss of islets, which can be prevented by grafting in a prevascularized, subcutaneous scaffold. Supporting vascularization of a scaffold to limit the period of ischemia is challenging and was developed here by

  3. Free jejunal graft for esophageal reconstruction using end-to-side vascular anastomosis and extended pharyngo-jejunostomy.

    Science.gov (United States)

    Lee, Hyun-Sung; Park, Seong Yong; Jang, Hee-Jin; Kim, Moon Soo; Lee, Jong Mog; Zo, Jae Ill

    2012-06-01

    Pharyngo-esophageal reconstruction using free jejunal grafts (FJGs) has been widely used, but the procedure is technically demanding and requires the involvement of multiple departments. We performed simplified reconstruction with FJGs using end-to-side vascular anastomosis and extended pharyngo-jejunostomy. The jejunal artery and vein were anastomosed to the neck vessels in an end-to-side fashion without microvascular anastomosis. Pharyngo-jejunostomy with extended end-to-end anastomosis was performed to reduce size mismatch. We retrospectively analyzed the medical records of 32 patients diagnosed with pharyngeal, esophageal, or pyriform sinus cancer who received a FJG. The mean age was 61.5±9.4 years, and there were 25 male patients. Jejunal vessels were commonly anastomosed to the right common carotid artery and the right internal jugular vein (22, 68.8%). The mean ischemic times of the FJG and carotid artery clamping time were 46.5±8.1 and 15.8±4.4 minutes, respectively. During the procedure, 3 patients suffered from inadequate reperfusion of the FJG requiring removal of the initial graft and replacement with another FJG. There were no neurologic complications, postoperative deaths, or adverse events directly related to FJG except for leakage of the pharyngo-jejunostomy site in 1 patient, which was primarily repaired. During the follow-up period, 5 patients (15.6%) suffered from dysphagia, but only 3 patients had evidence of anastomotic strictures at the jejuno-esophagostomy site. Thirteen patients (40.6%) received postoperative adjuvant radiotherapy. Our technique of FJG with end-to-side vascular anastomosis and extended pharyngo-jejunostomy is simple and safe. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  4. Implant stability and peri-implant parameters in free vascularized iliac graft transplantation patients: report of three ameloblastoma cases.

    Science.gov (United States)

    Tözüm, Tolga F; Sönmez, Erhan; Askin, Sezen B; Tulunoglu, Ibrahim; Safak, Tunc

    2011-02-01

    Ameloblastoma, a benign but locally aggressive tumor, accounts for 9% to 11% of all odontogenic tumors. Radical procedures, including resection, are performed. To restore functions after resection, free vascularized iliac grafts followed by a dental implant-supported prosthesis are used as a successful treatment option. The aim of this case report is to evaluate the peri-implant clinical status and stability of dental implants placed in patients with advanced-stage mandibular ameloblastomas. Examinations of three patients revealed extensive ameloblastomas, and hemimandibulectomies were performed. Six months after surgeries, two to four dental implants were placed. After 6 months of healing, one fixed prosthesis and two removable prostheses were delivered. The stability of implants was evaluated at the surgical baseline and 1, 3, 6, 9, and 12 months after surgery by resonance-frequency (RF) analysis. Peri-implant clinical parameters (i.e., plaque index [PI], gingival index [GI], gingival bleeding time index [GBTI], and peri-implant probing depth [PD]) were recorded at the delivery of the prosthesis and at follow-ups at 1, 3, and 6 months. Nine implants that supported one removable prosthesis and two fixed prostheses were placed. RF analysis revealed no significant changes in implant stability during 12 months of follow-up. Peri-implant clinical parameters (PI, GI, and GBTI) showed slight improvements during follow-up. Although advancements were observed in 6 months, PDs were found to be deeper than optimal measurements for the whole observation time. The implant-supported prosthetic rehabilitation of patients with ameloblastomas reconstructed with free vascularized iliac crest grafts can be a predictive alternative for improving the quality of life of patients in which a high implant stability and acceptable peri-implant health may be achieved.

  5. Influx of immunoglobulins from the vascular compartment into a grafted cornea.

    Science.gov (United States)

    Van der Veen, G; Broersma, L; Bruyne, I; Verhagen, C; Ruijter, J; Van Rij, G; Van der Gaag, R

    1997-04-01

    To determine the effect of a fresh corneal wound or a healed corneal scar on the immunodiffusion of immunoglobulins into the cornea. F344 rats were immunized with human serum albumin (HSA) 1 week before an autologous rotational keratoplasty of the right cornea or 1 year after an autograft was performed. One group of rats also was treated with gentamicin-dexamethasone ointment in the grafted eye for 1 week after transplantation to reduce the postsurgical inflammatory signs. A serum sample was drawn every week and booster injections with HSA were given after 2 and 3 weeks. At various times after immunization, groups of rats were killed, blood and aqueous humor samples were taken, and the corneas of both eyes were removed. The corneas were divided into the graft or a 3-mm central button and the peripheral rim and weighed. The anti-HSA titer was determined in serum, aqueous humor, and both parts of the corneas. Up to 5 weeks after transplantation, the grafted cornea contained more anti-HSA immunoglobulins than did the control eye. One year postgrafting, no difference was seen. In the first weeks after keratoplasty, influx of anti-HSA from the peripheral into the central cornea was, however, neither obstructed nor enhanced. Surgical trauma in itself causes increased influx of anti-HSA immunoglobulins into the cornea. Within the cornea, a wound or a scar does not appear to be a barrier for centripetal immunoglobulin diffusion.

  6. Secondary skull reconstruction with autogenous split calvarial bone grafts versus nonautogenous materials.

    Science.gov (United States)

    Lee, Hee Jong; Choi, Jong Woo; Chung, In Wook

    2014-07-01

    Skull reconstructions, which can be required for various reasons, including decompressive craniectomy, trauma, and tumors, are challenging issues in plastic surgery. Moreover, obtaining a low complication ratio in secondary skull reconstructions is more difficult than in primary skull reconstructions. Because standardized protocols have not been established, we here compare cranioplasty performance using fresh autogenous split calvarial bone grafts and allogenic or alloplastic materials in secondary revisional cases. Surgical correction of skull defects was performed in 25 patients in our center between 2005 and 2012. Only secondary cranioplasty cases were reviewed retrospectively. There were 17 men and 8 women, with ages ranging from 8 to 62 years at the time of surgery. The mean follow-up was 55.6 months. The surgical procedure in each case was a routine cranioplasty. In most of the cases, a 1-piece split calvarial bone graft was used while minimizing the separation of the bone flap into multiple pieces. In comparison with the skull reconstructional approach using nonautogenous materials, the functional and esthetic results of skull reconstruction using autogenous calvarial bone grafts were better and more consistent in secondary revisional cases. The group that received autogenous calvarial bone grafts showed a reconstruction success rate of 80% without esthetic and functional complications. In contrast, the group that received nonautogenous materials had a 30% success rate. Secondary cranial defect reconstructions with autogenous calvarial bone grafts showed better functional and esthetic results than skull reconstructions with nonautogenous materials.

  7. Comparison of Direct Site Endovascular Repair Utilizing Expandable PTFE Stent Grafts Vs. Standard Vascular Shunts in a Porcine (Sus Scrofa) Model.

    Science.gov (United States)

    Davidson, Anders J; Neff, Lucas P; Grayson, J Kevin; Clement, Nathan F; DeSoucy, Erik S; Simon-Logan, Meryl A; Abbot, Christopher M; Sampson, James B; Williams, Timothy K

    2017-07-08

    The small diameter of temporary vascular shunts for vascular trauma management may restrict flow and result in ischemia or early thrombosis. We have previously reported a clinical experience with direct, open surgical reconstruction using expanded polytetrafluoroethylene (ePTFE) stent grafts to create a "sutureless" anastomosis as an alternative to standard temporary vascular shunts. We sought to characterize patency and flow characteristics of these grafts compared to standard shunts in a survival model of porcine vascular injury. 12 Yorkshire-cross swine received a 2cm long near-circumferential defect in the bilateral iliac arteries. A14-French Argyle shunt was inserted into one randomly assigned artery, with a self-expanding ePTFE stent deployed in the other. At 72 hours, conduit patency was evaluated by angiography. Arterial flow measurements were obtained at baseline, immediately after intervention, and after 72 hours via direct measurement with perivascular flow meters. Blood pressure proximal and distal to the conduits and arterial samples for histopathology were obtained during the terminal procedure. Angiography revealed no difference in patency at 72 hours (P=1.0). While there was no difference in baseline arterial flow between arteries (P=0.63), the stent grafts demonstrated significantly improved blood flow compared to shunts both immediately after intervention (390±36mL/min vs 265±25mL/min, p=0.002) and at 72 hours (261±29mL/min vs 170±36mL/min, p=0.005). The pressure gradient across the shunts was greater than that of the stent grafts (11.5mmHg IQR[3-19] vs. 3mmHg IQR[3-5], p=0.013). The speed of deployment was similar between the two devices. Open "sutureless" direct site repair using commercially available stent grafts to treat vascular injury is a technically feasible strategy for damage control management of peripheral vascular injury and offers increased blood flow when compared to temporary shunts. Furthermore, stent grafts may offer

  8. Comparison of direct site endovascular repair utilizing expandable polytetrafluoroethylene stent grafts versus standard vascular shunts in a porcine (Sus scrofa) model.

    Science.gov (United States)

    Davidson, Anders J; Neff, Lucas P; Grayson, J Kevin; Clement, Nathan F; DeSoucy, Erik S; Simon Logan, Meryl A; Abbot, Christopher M; Sampson, James B; Williams, Timothy K

    2017-09-01

    The small diameter of temporary vascular shunts for vascular trauma management may restrict flow and result in ischemia or early thrombosis. We have previously reported a clinical experience with direct, open surgical reconstruction using expandable polytetrafluoroethylene stent grafts to create a "sutureless" anastomosis as an alternative to standard temporary vascular shunts. We sought to characterize patency and flow characteristics of these grafts compared with standard shunts in a survival model of porcine vascular injury. Twelve Yorkshire-cross swine received a 2-cm-long near-circumferential defect in the bilateral iliac arteries. A 14 Fr Argyle shunt was inserted into one randomly assigned artery, with a self-expanding expandable polytetrafluoroethylene stent deployed in the other. At 72 hours, conduit patency was evaluated by angiography. Arterial flow measurements were obtained at baseline, immediately after intervention, and after 72 hours via direct measurement with perivascular flow meters. Blood pressure proximal and distal to the conduits and arterial samples for histopathology were obtained during the terminal procedure. Angiography revealed no difference in patency at 72 hours (p = 1.0). While there was no difference in baseline arterial flow between arteries (p = 0.63), the stent grafts demonstrated significantly improved blood flow compared with shunts both immediately after intervention (390 ± 36 mL/min vs. 265 ± 25 mL/min, p = 0.002) and at 72 hours (261 ± 29 mL/min vs. 170 ± 36 mL/min, p = 0.005). The pressure gradient across the shunts was greater than that of the stent grafts (11.5 mm Hg [interquartile range, 3-19 mm Hg] vs. 3 mm Hg [interquartile range, 3-5 mm Hg], p = 0.013). The speed of deployment was similar between the two devices. Open "sutureless" direct site repair using commercially available stent grafts to treat vascular injury is a technically feasible strategy for damage control management of peripheral vascular injury and

  9. Treatment of screw hole defects using bone graft materials: a histologic and biomechanic study.

    Science.gov (United States)

    York, M J; Hutton, W C

    1996-01-01

    We surgically applied compression plates, secured with cortical screws, to the anterolateral surface of each radius in 20 dogs. Five weeks later, the plates and screws were removed. The dogs were then divided into four groups of 5, and each group had the screw holes in the left radii filled with a different form of bone graft material. The screw holes in the right radii received no graft material and served as controls. Five weeks later the dogs were euthanized, and the radii were removed and torqued to failure. All bones failed through a previous screw hole. An analysis of variance comparing all grafted radii to the ungrafted controls revealed no significant difference in torque to failure. This suggests that both grafted and ungrafted screw holes still increase stress at 5 weeks, and any period of protection after plate removal should be longer than 5 weeks. However, histology revealed that the holes filled with graft material had, in every case, more bone in the screw holes than did the holes in the ungrafted controls.

  10. Biological interface of bone graft substitute materials : experimental studies on interactions between biomaterials and bone cells

    OpenAIRE

    Mladenovic, Zivko

    2011-01-01

    Bone graft substitute materials are becoming more common as alternative therapy strategies when bone defects in patients need to be treated. The interaction between bone cells and biomaterials occur at the surface of the materials. A great deal is known about the importance of surface topography and physic-chemical properties of biomaterials. It is also known that cells require proteins in order to interact with biomaterials. Less is known about how material properties and proteins interact f...

  11. Comparative Evalution of G bone (Hydroxyapatite) and G-Graft (Hydroxyapatite with Collagen) as Bone Graft Material in Mandibular III Molar Extraction Socket.

    Science.gov (United States)

    Panday, Vijayendra; Upadhyaya, Vivekananda; Berwal, Vikas; Jain, Kapil; Sah, Nupur; Sarathi, Partha; Swami, Pushp Chander

    2015-03-01

    Bone grafting is a dynamic phenomenon. It is a surgical procedure that replaces missing bone with material either from patient's own body, or, an artificial, synthetic or natural substitute. A successful bone graft when applied, heals, becomes incorporated, re-vascularises and eventually assumes the form desired. The main purpose of this present study was to radiologically assess and compare the regenerative potential of hydroxyapatite with Collagen (G-Graft) and hydroxyapatite (G-Bone) and to evaluate the clinical usefulness of these materials to enhance bone healing in third molar extraction sites through bone formation. The study was carried out in the Department of Oral & Maxillofacilal Surgery, patients were divided into three groups. The rationale for assigning the patients to the groups was strictly random: Group I - G-Graft (Hydroxyapatite with Collagen) was used as Bone graft material, Group II - Bone graft material used was G-Bone (Hydroxyapatite), Group III-control group (no grafts was used). Orthopentomogram(OPG) images were taken intra-operatively, just after extraction in the Group III (control), after extraction but before graft placement in Group I & II (study groups) and post-operatively at the end of first month and third month. Bone density of the post-extraction sockets was measured at four random areas through 'densitometric analysis' software in the OPG program (Kodak 8000C Digital Panoramic System, Eastman Kodak Company) and an average value was recorded at each review. The percentage increase in bone density between 1(st) month & 3(rd) month was 7.55± 12.43 in Group I (G Graft), 4.41± 5.4859 in Group II (G Bone), while that Group III (control) was found to be -0.82 ± 3.96. The bone density increase was found to be statistically highly significant (p<0.01)) between all groups. The present study concluded that G-Graft has a definite regenerative potential and is better than G-bone and can be used in bony defects to enhance the bone healing

  12. Fresh-frozen bone: case series of a new grafting material for sinus lift and immediate implants.

    LENUS (Irish Health Repository)

    Viscioni, A

    2010-08-01

    Although autologous bone is considered to be the gold standard grafting material, it needs to be harvested from patients, a process that can be off-putting and can lead to donor site morbidity. For this reason, homologous fresh-frozen bone (FFB) was used in the current study as an alternative graft material.

  13. Migration of alloplastic bone graft material in infected conditions: a case study and animal experiment.

    Science.gov (United States)

    Seok, Hyun; Lee, Seuk-Keun; Kim, Seong-Gon; Kang, Tae-Yeon; Lee, Myung-Jin; Chae, Weon-Sik

    2014-06-01

    Distant migration associated with sinus lifting procedures has not been investigated. In the present study, a case of distant migration of graft material was observed, and the potential mechanisms of migration were analyzed using material analysis and in vivo experiments. The migrated graft material was biphasic calcium phosphate-based alloplastic material (BCP), and its physical properties were compared with those of xenogenic material (Bio-Oss). The comparisons of the physical properties were performed using scanning electronic microscopic, x-ray diffraction, and Fourier-transform infrared absorbance spectra analysis. The comparative graft migration study was performed using the subcutaneous pocket model in rats (n = 10). The clinical case was analyzed by histologic section and energy dispersive x-ray (EDX) microanalysis. The observed diffraction patterns from the Bio-Oss revealed characteristic diffractions for the hydroxyapatite phase, and those from the BCP revealed additional diffractions that could be assigned to the tricalcium phosphate phase. In the animal model, the graft migration distances observed in the BCP group were significantly greater than those observed in the Bio-Oss group (P = .012). In the clinical case, the lymphatic vessels of the submandibular gland contained foreign materials that were morphologically similar to those of the maxillary sinus. EDX microanalysis revealed that the particles in the lymphatic vessels exhibited calcium concentrations that were approximately 200 times greater than those in the adjacent glandular tissue. In the present study, BCP-based sinus grafts had migrated into the submandibular glandular area by way of the lymphatic chain in the presented clinical case. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  14. Endovascular repair of postoperative vascular graft related complications after aorto-iliac surgery

    DEFF Research Database (Denmark)

    Duvnjak, Stevo; Andersen, P E; Larsen, K E

    2014-01-01

    AIM: Para-anastomotic aneurysms, leakage due to anastomotic failure, aorto- and arterioenteric fistulas are some of the serious complications after aorto-iliac surgical reconstructions. Treatment of these complications is challenging and is either done by open surgery or by endovascular therapy...... endoprosthesis was implanted in one case and in two cases aortic cuff was used. Fluency periphery stent grafts were used in four cases. There was a 100% technical success. Intervention related early mortality was 8%. One patient with pseudoaneurysm died 28 months after endovascular treatment because of cardiac...... infarct and one patient with previously infected arterio-enteric fistula and advanced malignancy died 7 months after second endovascular treatment. Overall the mortality was 25%. There was no procedure related morbidity or complications during hospitalization and follow-up of mean 12, 3 months (range 1...

  15. Effect of sterilization on non-woven polyethylene terephthalate fiber structures for vascular grafts.

    Science.gov (United States)

    Dimitrievska, Sashka; Petit, Alain; Doillon, Charles J; Epure, Laura; Ajji, Abdellah; Yahia, L'Hocine; Bureau, Martin N

    2011-01-10

    Non-woven polyethylene terephthalate (PET) fibers produced via melt blowing and compounded into a 6 mm diameter 3D tubular scaffold were developed with artery matching mechanical properties. This work compares the effects of ethylene oxide (EtO) and low temperature plasma (LTP) sterilization on PET surface chemistry and biocompatibility. As seen through X-ray photoelectron spectroscopy (XPS) analysis, LTP sterilization led to an increase in overall oxygen content and the creation of new hydroxyl groups. EtO sterilization induced alkylation of the PET polymer. The in vitro cytotoxicity showed similar fibroblastic viability on LTP- and EtO-treated PET fibers. However, TNF-α release levels, indicative of macrophage activation, were significantly higher when macrophages were incubated on EtO-treated PET fibers. Subcutaneous mice implantation revealed an inflammatory response with foreign body reaction to PET grafts independent of the sterilization procedure. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Human fingernail as interpositional graft material in the treatment of nasal septal perforations.

    Science.gov (United States)

    Akçal, Arzu; Karsidag, Semra; Ozkaya, Ozay; Sirvan, Selami Serhat; Sevim, Kamuran Zeynep; Kabukcuoglu, Fevziye

    2014-04-01

    The etiology of nasal septal perforations involves iatrogenic, traumatic, inflammatory, infectious, neoplastic, and caustic causes. To ensure successful closure, an appropriate interpositional graft material should be selected, and this graft material should be covered with healthy tissue. The study included 18 New Zealand white rabbits weighing 2 to 2.5 kg. Nasal septal perforations were created in group 1. After the creation of defects in group 2, repair was performed with cartilage graft and bilateral mucoperichondrial advancement flaps. After septal nasal perforations in group 3, the defect was covered with fingernail and bilateral mucoperichondrial flaps. At week 12, the rabbits were sacrificed. The septum site that had been repaired with fingernail was intact. No nail exposition, wound site decomposition, or re-perforation was observed. No findings of a breach of the structural integrity of the fingernails or disintegration were encountered. Fingernails can be used as an interpositional graft material in place of cartilage in eligible cases for the repair of nasal septal perforations. Fingernails have several properties that enable their use in such cases, such as form preservation that is similar to cartilage, the lack of live cells, easy availability, and a lack of donor-site morbidity at removal. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  17. Bioreactor activated graft material for early implant fixation in bone

    DEFF Research Database (Denmark)

    Snoek Henriksen, Susan; Ding, Ming; Overgaard, Søren

    2011-01-01

    Technological Institute, Denmark). The granules were coated with poly-lactic acid (PLA) 12%, in order to increase the mechanical strength of the material (Phusis, France). Scaffold granules (Ø~900-1400 µm, 80% porosity) in group 2 consisted of pure HA/β-TCP (FinCeramica, Italy). For both groups, cells were...

  18. Application of high-tech three-dimensional imaging and computer-generated models in complex facial reconstructions with vascularized bone grafts.

    Science.gov (United States)

    Rose, E H; Norris, M S; Rosen, J M

    1993-02-01

    We present a series of six patients with eight flaps in whom computer-generated models were used for fabrication of vascularized bone grafts in complex facial restorations. Preoperative CT data, digitalized on tape, were converted by the CEMAX (Santa Clara, Calif.) 1500 Integrated Hardware and Software System to a three-dimensional visualization of the bone and soft-tissue deficiencies. These data were transmitted by direct computer link to a CNC milling machine that produced full-size slices "stacked" into a three-dimensional template. The acrylic replica aided selection of appropriate donor sites and intraoperative "carving" of bone transfers. Reconstructions included three zygomas, two maxillae, two mandibles, and one frontal bone. Donor sites were iliac crest, scapula, and outer calvarium. Four were free flaps and four island pedicle flaps. All healed without infection. Bone resorption was less than 10 percent. One flap was lost to thrombosis. Other complications included a transient facial palsy in one patient and temporary radial palsy from shoulder traction in another. Computer-generated templates for vascularized grafts are expensive and thus are not indicated or necessary in every patient. The advantages, however, are several. Custom models facilitate preoperative planning, with less guesswork of size, contour, and orientation of the graft, which is especially desirable with vascularized grafts, since the position of the pedicle is critical. Anesthesia time is decreased. Grafts can be fitted exactly, without reshaping and "nibbling." Nuances of depth and tapering are directly carved into the bone. By merging high-tech imaging and microsurgery, the best chance of optimal results can be achieved.

  19. The effect of postoperative corticosteroid administration on free vascularized fibular grafting for treating osteonecrosis of the femoral head.

    Science.gov (United States)

    Ding, Hao; Chen, Sheng-Bao; Lin, Sen; Gao, You-Shui; Zhang, Chang-Qing

    2013-01-01

    Free vascularized fibular grafting (FVFG) has been reported to be an effective method of treating osteonecrosis of the femoral head (ONFH). This study evaluated whether postoperative maintenance doses of corticosteroids had an adverse effect on FVFG outcomes in patients with corticosteroid-induced ONFH. We retrospectively reviewed the records of 39 patients (67 hips) who had received maintenance doses of corticosteroids following FVFG. This group was matched to a group of patients who had not received corticosteroids treatment after operation. The mean follow-up duration was 5.4 years for the postoperative corticosteroid administration group (PCA group) and 5.0 years for the control group. At the latest follow-up, the average increase in Harris hip score was 11.1 ± 8.7 points for all hips in the PCA group and 12.6 ± 7.4 points for all hips in the control group (P > 0.05). In the PCA group, through radiographic evaluation, 49 hips were improved, 10 hips appeared unchanged, and 8 hips appeared worse. In the control group, 47 hips were improved, 13 hips appeared unchanged, and 7 hips appeared worse. The results suggested that postoperative maintenance doses of corticosteroids do not have an adverse effect on FVFG outcomes in patients with corticosteroid-induced ONFH.

  20. The Effect of Postoperative Corticosteroid Administration on Free Vascularized Fibular Grafting for Treating Osteonecrosis of the Femoral Head

    Directory of Open Access Journals (Sweden)

    Hao Ding

    2013-01-01

    Full Text Available Free vascularized fibular grafting (FVFG has been reported to be an effective method of treating osteonecrosis of the femoral head (ONFH. This study evaluated whether postoperative maintenance doses of corticosteroids had an adverse effect on FVFG outcomes in patients with corticosteroid-induced ONFH. We retrospectively reviewed the records of 39 patients (67 hips who had received maintenance doses of corticosteroids following FVFG. This group was matched to a group of patients who had not received corticosteroids treatment after operation. The mean follow-up duration was 5.4 years for the postoperative corticosteroid administration group (PCA group and 5.0 years for the control group. At the latest follow-up, the average increase in Harris hip score was 11.1 ± 8.7 points for all hips in the PCA group and 12.6 ± 7.4 points for all hips in the control group (P>0.05. In the PCA group, through radiographic evaluation, 49 hips were improved, 10 hips appeared unchanged, and 8 hips appeared worse. In the control group, 47 hips were improved, 13 hips appeared unchanged, and 7 hips appeared worse. The results suggested that postoperative maintenance doses of corticosteroids do not have an adverse effect on FVFG outcomes in patients with corticosteroid-induced ONFH.

  1. Cu(II) recognition materials: Fluorophores grafted on mesoporous silica supports

    Energy Technology Data Exchange (ETDEWEB)

    Kledzik, Krzysztof; Orlowska, Maja [Faculty of Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Patralska, Dorota [Institute of Organic Chem., Pol. Acad. Sciences, Kasprzaka 44, 01-224 Warsaw (Poland); Gwiazda, Marcin [Faculty of Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Jezierska, Julia [Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw (Poland); Pikus, Stanislaw [Faculty of Chemistry, M. Curie-Sklodowska University, M. Curie Sklodowska 3, 20-031 Lublin (Poland); Ostaszewski, Ryszard [Institute of Organic Chem., Pol. Acad. Sciences, Kasprzaka 44, 01-224 Warsaw (Poland)], E-mail: rysza@icho.edu.pl; Klonkowski, Andrzej M. [Faculty of Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)], E-mail: aklonk@chem.univ.gda.pl

    2007-11-15

    There were designed and synthesized naphthalene and pyrene derivatives consisting of fluorophore group and of receptor fragment with donor N and O atoms. These fluorosensors were covalently attached by grafting carboxyl group to surfaces of silica xerogel or mesoporous silicas (MCM-41 and MCM-48) functionalized either with 3-aminopropyl or 3-glycidoxypropyl groups. The pyrene derivatives 2 and 3 covalently grafted on MCM-48 silica functionalized with 3-aminopropyl groups are potential recognition elements of a fluorescence chemical sensor. Fluorescence emission of the prepared recognition materials is quenched specifically owing to photoinduced electron transfer (PET) effect after coordination reactions with Cu(II) ions. Moreover, both the materials exhibit selectivity for Cu(II) ions in aqueous solutions in presence of such metal ions as: alkali, alkaline earth and transition. During UV irradiation the studied recognition elements undergo slowly photochemical degradation.

  2. Fabrication and characterisation of biomimetic, electrospun gelatin fibre scaffolds for tunica media-equivalent, tissue engineered vascular grafts

    Energy Technology Data Exchange (ETDEWEB)

    Elsayed, Y. [Advanced Materials Group, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Lekakou, C., E-mail: C.Lekakou@surrey.ac.uk [Advanced Materials Group, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Labeed, F. [Centre of Biomedical Engineering, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Tomlins, P. [National Physical Laboratory (NPL), Teddington, Middlesex TW11 0LW (United Kingdom)

    2016-04-01

    It is increasingly recognised that biomimetic, natural polymers mimicking the extracellular matrix (ECM) have low thrombogenicity and functional motifs that regulate cell–matrix interactions, with these factors being critical for tissue engineered vascular grafts especially grafts of small diameter. Gelatin constitutes a low cost substitute of soluble collagen but gelatin scaffolds so far have shown generally low strength and suture retention strength. In this study, we have devised the fabrication of novel, electrospun, multilayer, gelatin fibre scaffolds, with controlled fibre layer orientation, and optimised gelatin crosslinking to achieve not only compliance equivalent to that of coronary artery but also for the first time strength of the wet tubular acellular scaffold (swollen with absorbed water) same as that of the tunica media of coronary artery in both circumferential and axial directions. Most importantly, for the first time for natural scaffolds and in particular gelatin, high suture retention strength was achieved in the range of 1.8–1.94 N for wet acellular scaffolds, same or better than that for fresh saphenous vein. The study presents the investigations to relate the electrospinning process parameters to the microstructural parameters of the scaffold, which are further related to the mechanical performance data of wet, crosslinked, electrospun scaffolds in both circumferential and axial tubular directions. The scaffolds exhibited excellent performance in human smooth muscle cell (SMC) proliferation, with SMCs seeded on the top surface adhering, elongating and aligning along the local fibres, migrating through the scaffold thickness and populating a transverse distance of 186 μm and 240 μm 9 days post-seeding for scaffolds of initial dry porosity of 74 and 83%, respectively. - Highlights: • Novel crosslinked electrospun gelatin scaffolds of specific fibre layer orientation • These scaffolds have compliance equivalent to that of coronary

  3. A randomized controlled trial and cost-effectiveness analysis of early cannulation arteriovenous grafts versus tunneled central venous catheters in patients requiring urgent vascular access for hemodialysis.

    Science.gov (United States)

    Aitken, Emma; Thomson, Peter; Bainbridge, Leigh; Kasthuri, Ram; Mohr, Belinda; Kingsmore, David

    2017-03-01

    Early cannulation arteriovenous grafts (ecAVGs) are proposed as an alternative to tunneled central venous catheters (TCVCs) in patients requiring immediate vascular access for hemodialysis (HD). We compared bacteremia rates in patients treated with ecAVG and TCVC. The study randomized 121 adult patients requiring urgent vascular access for HD in a 1:1 fashion to receive an ecAVG with or without (+/-) an arteriovenous fistula (AVF; n = 60) or TCVC+/-AVF (n = 61). Patients were excluded if they had active systemic sepsis, no anatomically suitable vessels, or an anticipated life expectancy vascular access for HD. The strategy also proved to be cost-neutral. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  4. A new Fe-Mn-Si alloplastic biomaterial as bone grafting material: In vivo study

    Science.gov (United States)

    Fântânariu, Mircea; Trincă, Lucia Carmen; Solcan, Carmen; Trofin, Alina; Strungaru, Ştefan; Şindilar, Eusebiu Viorel; Plăvan, Gabriel; Stanciu, Sergiu

    2015-10-01

    Designing substrates having suitable mechanical properties and targeted degradation behavior is the key's development of bio-materials for medical application. In orthopedics, graft material may be used to fill bony defects or to promote bone formation in osseous defects created by trauma or surgical intervention. Incorporation of Si may increase the bioactivity of implant locally, both by enhancing interactions at the graft-host interface and by having a potential endocrine like effect on osteoblasts. A Fe-Mn-Si alloy was obtained as alloplastic graft materials for bone implants that need long recovery time period. The surface morphology of the resulted specimens was investigated using scanning electrons microscopy (VegaTescan LMH II, SE detector, 30 kV), X-ray diffractions (X'Pert equipment) or X-ray dispersive energy analyze (Bruker EDS equipment). This study objective was to evaluate in vivo the mechanisms of degradation and the effects of its implantation over the main metabolic organs. Biochemical, histological, plain X radiography and computed tomography investigations showed good compatibility of the subcutaneous implants in the rat organism. The implantation of the Fe-Mn-Si alloy, in critical size bone (tibiae) defect rat model, did not induced adverse biological reactions and provided temporary mechanical support to the affected bone area. The biodegradation products were hydroxides layers which adhered to the substrate surface. Fe-Mn-Si alloy assured the mechanical integrity in rat tibiae defects during bone regeneration.

  5. Nano- and microstructured materials for in vitro studies of the physiology of vascular cells.

    Science.gov (United States)

    Greiner, Alexandra M; Sales, Adria; Chen, Hao; Biela, Sarah A; Kaufmann, Dieter; Kemkemer, Ralf

    2016-01-01

    The extracellular environment of vascular cells in vivo is complex in its chemical composition, physical properties, and architecture. Consequently, it has been a great challenge to study vascular cell responses in vitro, either to understand their interaction with their native environment or to investigate their interaction with artificial structures such as implant surfaces. New procedures and techniques from materials science to fabricate bio-scaffolds and surfaces have enabled novel studies of vascular cell responses under well-defined, controllable culture conditions. These advancements are paving the way for a deeper understanding of vascular cell biology and materials-cell interaction. Here, we review previous work focusing on the interaction of vascular smooth muscle cells (SMCs) and endothelial cells (ECs) with materials having micro- and nanostructured surfaces. We summarize fabrication techniques for surface topographies, materials, geometries, biochemical functionalization, and mechanical properties of such materials. Furthermore, various studies on vascular cell behavior and their biological responses to micro- and nanostructured surfaces are reviewed. Emphasis is given to studies of cell morphology and motility, cell proliferation, the cytoskeleton and cell-matrix adhesions, and signal transduction pathways of vascular cells. We finalize with a short outlook on potential interesting future studies.

  6. Tooth movement out of the bony wall using augmented corticotomy with nonautogenous graft materials for bone regeneration

    National Research Council Canada - National Science Library

    Lee, Kye-Bok; Lee, Dong-Yeol; Ahn, Hyo-Won; Kim, Seong-Hun; Kim, Eun-Cheol; Roitman, Igor

    2014-01-01

    This prospective randomized split-mouth study was performed to compare the effects of augmented corticotomy with those of different nonautogenous bone graft materials combined with orthodontic tooth movement in dogs...

  7. Pretreatment of synthetic vascular grafts with heparin before implantation, a simple technique to reduce the risk of thrombosis.

    Science.gov (United States)

    Gerrah, Rabin; Sunstrom Pa-C, Rachel E; Hohimer, Alan R

    2015-10-01

    Thrombosis of synthetic grafts commonly used in cardiovascular surgery is a major complication. We examined whether pretreatment of the graft with heparin reduces the risk of early thrombosis. A circuit was assembled to compare two pairs of shunts simultaneously in the same animal. The study shunts were pretreated with heparin. After 2 hours of circulation, clot formation was evaluated by image analysis techniques. The pretreated grafts had fewer blood clots adhered to the surface by direct visual inspection. The image analysis showed 5 vs. 39 clots, 0.01% vs. 1.8% clotted area, and 62 vs. 5630 clot pixel area between the treated and non-treated grafts respectively, p < 0.05. Pretreatment of the synthetic graft with heparin prior to implantation reduces the risk of early clot formation. This simple practice might be helpful to prevent initial thrombosis of the graft and later occlusion. © The Author(s) 2014.

  8. Design and preparation of polyurethane-collagen/heparin-conjugated polycaprolactone double-layer bionic small-diameter vascular graft and its preliminary animal tests.

    Science.gov (United States)

    Lu, Guang; Cui, Shi-Jun; Geng, Xue; Ye, Lin; Chen, Bing; Feng, Zeng-Guo; Zhang, Jian; Li, Zhong-Zhi

    2013-04-01

    People recently realized that it is important for artificial vascular biodegradable graft to bionically mimic the functions of the native vessel. In order to overcome the high risk of thrombosis and keep the patency in the clinical small-diameter vascular graft (SDVG) transplantation, a double-layer bionic scaffold, which can offer anticoagulation and mechanical strength simultaneously, was designed and fabricated via electrospinning technique. Heparin-conjugated polycaprolactone (hPCL) and polyurethane (PU)-collagen type I composite was used as the inner and outer layers, respectively. The porosity and the burst pressure of SDVG were evaluated. Its biocompatibility was demonstrated by the 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H tetrazolium bromide (MTT) test in vitro and subcutaneous implants in vivo respectively. The grafts of diameter 2.5 mm and length 4.0 cm were implanted to replace the femoral artery in Beagle dog model. Then, angiography was performed in the Beagle dogs to investigate the patency and aneurysm of grafts at 2, 4, and 8 weeks post-transplantation. After angiography, the patent grafts were explanted for histological analysis. The double-layer bionic SDVG meet the clinical mechanical demand. Its good biocompatibility was proven by cytotoxicity experiment (the cell's relative growth rates (RGR) of PU-collagen outer layer were 102.8%, 109.2% and 103.5%, while the RGR of hPCL inner layer were 99.0%, 100.0% and 98.0%, on days 1, 3, and 5, respectively) and the subdermal implants experiment in the Beagle dog. Arteriography showed that all the implanted SDVGs were patent without any aneurismal dilatation or obvious anastomotic stenosis at the 2nd, 4th, and 8th week after the operation, except one SDVG that failed at the 2nd week. Histological analysis and SEM showed that the inner layer was covered by new endothelial-like cells. The double-layer bionic SDVG is a promising candidate as a replacement of native small-diameter vascular graft.

  9. One-stage treatment and reconstruction of Gustilo Type III open tibial shaft fractures with a vascularized fibular osteoseptocutaneous flap graft.

    Science.gov (United States)

    Zhen, Ping; Hu, Yun-Yu; Luo, Zhuo-Jing; Liu, Xing-Yan; Lu, Hao; Li, Xu-Sheng

    2010-12-01

    This study evaluated the usefulness of a single-stage, free-fibular vascularized osteoseptocutaneous flap transfer for Type III open tibial shaft fractures with segmental bone loss for the reconstruction of combined bone and soft tissue defects. Nonrandomized retrospective study. University Level I trauma center. All Gustilo Type III open tibial shaft fractures with segmental bone loss that were treated at one institution between 2000 and 2007 were identified from a trauma registry. The study group consisted of 28 patients with Type III open tibial fractures: 27 were Gustilo-Anderson Type IIIB and one was Grade IIIC. The cause of tibial injury included eight industrial accidents, seven motor vehicle accidents, five crushing injuries caused by heavy objects, five falls from a height, and three motorcycle crashes. The lengths of the preoperative segmental tibial bone loss ranged from 9 to 17 cm and the size of the associated soft tissue defects ranged from 8 × 6 cm to 15 × 7 cm. The free fibular vascularized osteoseptocutaneous flap was used to graft and reconstruct combined bone and soft tissue defects. The radical wound débridement, soft tissue and bone revision, fracture stabilization, and early soft tissue coverage were achieved by this technique in a one-stage procedure. The average duration from injury to one-stage reconstruction was 15.8 hours (range, 5.3 hours to 6.5 days). Radiographic and functional evaluation of the lower extremity. All free fibular osteoseptocutaneous flaps survived completely. The average time to overall union for the entire group was 32 weeks after surgery (range, 26-41 weeks). None of the patients in this series had a nonunion. Acceptable radiographic alignment, defined as 5° of angulation in any plane, was obtained in 22 patients (78.6%). Malunion affected six (21.4%) fractures. According to the lower extremity functional assessment, excellent and good results were achieved for 82.1% (23 of 28), fair results were seen in 14

  10. Incorporation of photo-carbon monoxide releasing materials into electrospun scaffolds for vascular tissue engineering.

    Science.gov (United States)

    Michael, Eden; Abeyrathna, Nawodi; Patel, Aatish V; Liao, Yi; Bashur, Chris A

    2016-03-23

    Hyper-proliferation of smooth muscle cells (SMCs) and a reduction in endothelial cell function are reasons for poor patency rates of current tissue engineered small-diameter vascular grafts. The controlled delivery of carbon monoxide (CO), a gasotransmitter involved in cell signaling, could improve vascular cell function in these grafts. Current CO releasing molecules (CORMs) can improve endothelialization of injured vessels with appropriate doses, but they still have limitations. The goal of this project was to generate a novel tissue engineered scaffold that includes a non-toxic and photoactivatable CORM. This is the first use of a CORM for tissue engineering. The results demonstrated that CORM-loaded, electrospun poly(ɛ-caprolactone) scaffolds can be photo-activated and release CO. The fluorescence that develops after CO release can be used to non-destructively track the extent of reaction. Further, activation can occur when both dry and incubated in cell culture conditions. However, incubation in serum protein-containing media decreases the time frame for activation, demonstrating the importance of testing the release profile in culture conditions. Rat SMCs were able to attach, grow, and express contractile SMC markers on activated CORM-loaded meshes and controls. Overall, these findings demonstrate that CORM-loaded electrospun scaffolds provide a promising delivery system for vascular tissue engineering.

  11. Grafted, cross-linked carbon black as a double-layer capacitor electrode material

    Energy Technology Data Exchange (ETDEWEB)

    Richner, R.; Mueller, S.; Wokaun, A.

    2001-03-01

    Isocyanate prepolymers readily react with oxidic functional groups on carbon black. On carbon black grafted with diisocyanates, reactive isocyanate groups are available for cross-linking to a polyurethane system. This cross-linked carbon black was considered as a new active material for electrochemical electrodes. Active material for electric double-layer capacitor electrodes was produced which had values of specific capacitance of up to 200 F/g. Cross-linking efficiencies of up to 58 % of the polymers utilised were achieved. (author)

  12. The Effect of Bisphasic Calcium Phosphate Block Bone Graft Materials with Polysaccharides on Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Hyun-Sang Yoo

    2017-01-01

    Full Text Available In this study, bisphasic calcium phosphate (BCP and two types of polysaccharide, carboxymethyl cellulose (CMC and hyaluronic acid (HyA, were used to fabricate composite block bone grafts, and their physical and biological features and performances were compared and evaluated in vitro and in vivo. Specimens of the following were prepared as 6 mm diameter, 2 mm thick discs; BPC mixed with CMC (the BCP/CMC group, BCP mixed with crosslinked CMC (the BCP/c-CMC group and BCP mixed with HyA (the BCP/HyA group and a control group (specimens were prepared using particle type BCP. A scanning electron microscope study, a compressive strength analysis, and a cytotoxicity assessment were conducted. Graft materials were implanted in each of four circular defects of 6 mm diameter in calvarial bone in seven rabbits. Animals were sacrificed after four weeks for micro-CT and histomorphometric analyses, and the findings obtained were used to calculate new bone volumes (mm3 and area percentages (%. It was found that these two values were significantly higher in the BCP/c-CMC group than in the other three groups (p < 0.05. Within the limitations of this study, BCP composite block bone graft material incorporating crosslinked CMC has potential utility when bone augmentation is needed.

  13. Facile synthesis of novel soluble cellulose-grafted hyperbranched polymers as potential natural antimicrobial materials.

    Science.gov (United States)

    Demircan, Deniz; Zhang, Baozhong

    2017-02-10

    A new class of soluble cellulose-grafted hyperbranched polymers has been synthesized by a facile "hypergrafting" reaction using bis(2-chloroethyl)amine and soluble cellulose tosylates. The molecular structures of the obtained new materials were characterized by (13)C NMR, FTIR spectroscopy, and elemental analysis. The degree of substitution of the hyperbranched cellulose derivatives ranges between 0.13-0.53. The new cellulose-based materials were soluble in various polar aprotic organic solvents. The thermal properties of the new cellulose materials were investigated by thermal gravimetric analysis. Antibacterial activity of the new cellulose derivatives was evaluated by diffusion disk tests against various gram negative and positive bacteria. Our results suggested that the obtained natural cellulosic materials can act as effective polymeric biocides, and may have great potential in various antimicrobial materials applications. Copyright © 2016. Published by Elsevier Ltd.

  14. Preparation and characterization of thermal-responsive non-woven poly (propylene) materials grafted with N-isopropylacrylamide/β-cyclodextrin

    DEFF Research Database (Denmark)

    Amiri, Setareh; Zadhoush, Ali; Mallakpour, Shadpour

    2013-01-01

    A temperature-sensitive hydrogel was successfully grafted on the surface of non-woven poly(propylene) materials. This was carried out by the application of unmodified β-cyclodextrin and N-isopropylacrylamide monomer in order to develop new functional hydrogels for textile science and technology....... Graft polymerization technique was used to graft this temperature-sensitive hydrogel on the surface of plasma-treated non-woven poly(propylene) materials. Fourier transform infrared attenuated total reflection, scanning electron microscopy and elemental analyses confirmed the presence of poly......-sensitive property with a lower critical solution temperature (33.23°C) compared to a non-grafted hydrogel. The wicking time and contact angle measurements showed an improvement of the wicking ability and hydrophilicity of modified non-woven poly(propylene) materials. This investigation facilitates the preparation...

  15. A new Fe–Mn–Si alloplastic biomaterial as bone grafting material: In vivo study

    Energy Technology Data Exchange (ETDEWEB)

    Fântânariu, Mircea, E-mail: mfantanariu@uaiasi.ro [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Veterinary Medicine, Str. Aleea M. Sadoveanu, no. 8, 700489, Iasi (Romania); Trincă, Lucia Carmen, E-mail: lctrinca@uaiasi.ro [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, Str. Aleea M. Sadoveanu, no. 3, 700490, Iasi (Romania); Solcan, Carmen, E-mail: csolcan@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Veterinary Medicine, Str. Aleea M. Sadoveanu, no. 8, 700489, Iasi (Romania); Trofin, Alina, E-mail: aetrofin@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, Str. Aleea M. Sadoveanu, no. 3, 700490, Iasi (Romania); Strungaru, Ştefan, E-mail: strungaru_stefan@yahoo.com [“Alexandru Ioan Cuza” University, Faculty of Biology, Bulevardul Carol I, Nr.11, 700506, Iasi (Romania); Şindilar, Eusebiu Viorel, E-mail: esindilar@uaiasi.ro [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Veterinary Medicine, Str. Aleea M. Sadoveanu, no. 8, 700489, Iasi (Romania); Plăvan, Gabriel, E-mail: gabriel.plavan@uaic.ro [“Alexandru Ioan Cuza” University, Faculty of Biology, Bulevardul Carol I, Nr.11, 700506, Iasi (Romania); and others

    2015-10-15

    Highlights: • A Fe–Mn–Si alloy was obtained as alloplastic graft material for bone implants. • Fe–Mn–Si alloy degradation rate was preliminary evaluate with SEM and EDAX techniques. • Biochemical, histological, RX and CT investigations were done in rats with subcutaneous and tibiae implants. • Fe–Mn–Si alloy assured an ideal compromise between degradation and mechanical integrity during bone regeneration. - Abstract: Designing substrates having suitable mechanical properties and targeted degradation behavior is the key's development of bio-materials for medical application. In orthopedics, graft material may be used to fill bony defects or to promote bone formation in osseous defects created by trauma or surgical intervention. Incorporation of Si may increase the bioactivity of implant locally, both by enhancing interactions at the graft–host interface and by having a potential endocrine like effect on osteoblasts. A Fe–Mn–Si alloy was obtained as alloplastic graft materials for bone implants that need long recovery time period. The surface morphology of the resulted specimens was investigated using scanning electrons microscopy (VegaTescan LMH II, SE detector, 30 kV), X-ray diffractions (X’Pert equipment) or X-ray dispersive energy analyze (Bruker EDS equipment). This study objective was to evaluate in vivo the mechanisms of degradation and the effects of its implantation over the main metabolic organs. Biochemical, histological, plain X radiography and computed tomography investigations showed good compatibility of the subcutaneous implants in the rat organism. The implantation of the Fe–Mn–Si alloy, in critical size bone (tibiae) defect rat model, did not induced adverse biological reactions and provided temporary mechanical support to the affected bone area. The biodegradation products were hydroxides layers which adhered to the substrate surface. Fe–Mn–Si alloy assured the mechanical integrity in rat tibiae defects

  16. Application of a Mixed Material Graft to Posterior Intravaginal Slingoplasty Procedure: Preliminary Pilot Series.

    Science.gov (United States)

    Vural, Birol; Çakıroglu, Yigit; Vural, Fisun; Yıldırım, Sule Köpük

    2017-05-01

    Good anatomic outcomes have been achieved with transvaginal synthetic materials in pelvic organ prolapse, but mesh-related complications are a major health concern. Therefore, developing new synthetic or biological materials with increased tissue strength and decreased complications are major challenges. This paper presents preliminary pilot series of Posterior Intravaginal Slingoplasty (PIVS) procedure performed with mixed material graft containing both autologous tissue and a synthetic material. Six women with symptomatic Utero-Vaginal Prolapse (UVP) ≥ stage 2 underwent the PIVS procedure. Pelvic floor symptoms were assessed with the Pelvic Organ Prolapse Quantification (POP-Q) system, Pelvic Floor Distress Inventory (PFDI), and the Pelvic Floor Impact Questionnaire (PFIQ) both before the procedure and 36 months after the surgery. There were no mesh-related complications or recurrence and all the patients had good functional and anatomic outcomes. These preliminary results are promising, but further long-term studies with a larger series are needed.

  17. Application of a Mixed Material Graft to Posterior Intravaginal Slingoplasty Procedure: Preliminary Pilot Series

    Science.gov (United States)

    Vural, Birol; Çakıroglu, Yigit; Yıldırım, Sule Köpük

    2017-01-01

    Good anatomic outcomes have been achieved with transvaginal synthetic materials in pelvic organ prolapse, but mesh-related complications are a major health concern. Therefore, developing new synthetic or biological materials with increased tissue strength and decreased complications are major challenges. This paper presents preliminary pilot series of Posterior Intravaginal Slingoplasty (PIVS) procedure performed with mixed material graft containing both autologous tissue and a synthetic material. Six women with symptomatic Utero-Vaginal Prolapse (UVP) ≥ stage 2 underwent the PIVS procedure. Pelvic floor symptoms were assessed with the Pelvic Organ Prolapse Quantification (POP-Q) system, Pelvic Floor Distress Inventory (PFDI), and the Pelvic Floor Impact Questionnaire (PFIQ) both before the procedure and 36 months after the surgery. There were no mesh-related complications or recurrence and all the patients had good functional and anatomic outcomes. These preliminary results are promising, but further long-term studies with a larger series are needed. PMID:28658857

  18. Evaluation of bone response to synthetic bone grafting material treated with argon-based atmospheric pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Beutel, Bryan G., E-mail: bryanbeutel@gmail.com; Danna, Natalie R.; Gangolli, Riddhi; Granato, Rodrigo; Manne, Lakshmiprada; Tovar, Nick; Coelho, Paulo G.

    2014-12-01

    Bone graft materials are utilized to stimulate healing of bone defects or enhance osseointegration of implants. In order to augment these capabilities, various surface modification techniques, including atmospheric pressure plasma (APP) surface treatment, have been developed. This in vivo study sought to assess the effect of APP surface treatment on degradation and osseointegration of Synthograft™, a beta-tricalcium phosphate (β-TCP) synthetic bone graft. The experimental (APP-treated) grafts were subjected to APP treatment with argon for a period of 60 s. Physicochemical characterization was performed by environmental scanning electron microscopy, surface energy (SE), and x-ray photoelectron spectroscopy analyses both before and after APP treatment. Two APP-treated and two untreated grafts were surgically implanted into four critical-size calvarial defects in each of ten New Zealand white rabbits. The defect samples were explanted after four weeks, underwent histological analysis, and the percentages of bone, soft tissue, and remaining graft material were quantified by image thresholding. Material characterization showed no differences in particle surface morphology and that the APP-treated group presented significantly higher SE along with higher amounts of the base material chemical elements on it surface. Review of defect composition showed that APP treatment did not increase bone formation or reduce the amount of soft tissue filling the defect when compared to untreated material. Histologic cross-sections demonstrated osteoblastic cell lines, osteoid deposition, and neovascularization in both groups. Ultimately, argon-based APP treatment did not enhance the osseointegration or degradation of the β-TCP graft. Future investigations should evaluate the utility of gases other than argon to enhance osseointegration through APP treatment. - Highlights: • Degradation/osseointegration of bone graft treated with argon-based APP is studied. • APP treatment did

  19. The Mechanical Characterization and IN VIVO Evaluation of Porous TiNi as Graft Material

    Science.gov (United States)

    Arpak, Bertan; Araz, Kenan; Nakaş, Ipek; Bor, Şakir; Nergiz, Ibrahim

    2012-09-01

    To obtain TiNi foams with interconnected pores that have surface quality necessary for bone growth in addition to required mechanical performance, sintering with the space holder technique was employed in this study, which aimed to evaluate the bone healing process of TiNi graft materials. For this purpose, processed TiNi foams with three different porosities were placed into the created defects in the femur of rats. Moreover, the mechanical properties of the processed TiNi foams were conducted via monotonic compression tests in order to evaluate mechanical biocompatibility.

  20. Dual biofunctional polymer modifications to address endothelialization and smooth muscle cell integration of ePTFE vascular grafts.

    Science.gov (United States)

    Bastijanic, Jennifer M; Kligman, Faina L; Marchant, Roger E; Kottke-Marchant, Kandice

    2016-01-01

    Expanded polytetrafluoroethylene (ePTFE) grafts were coated on the luminal surface with a cell-adhesive fluorosurfactant (FSP) polymer to promote endothelialization, followed by ethanol hydration to degas the pores and subsequent cell-adhesive, enzymatically degradable poly(ethylene glycol)-based hydrogel incorporation into the graft interstices to accommodate potential smooth muscle cell integration in the graft wall. The FSP coating on ePTFE was stable as demonstrated by a significantly reduced receding water contact angle on FSP-coated ePTFE (14.5 ± 6.4°) compared to uncoated ePTFE (105.3 ± 4.5°, P < 0.05) after ethanol exposure. X-ray photoelectron spectroscopy analysis of the same surfaces confirmed FSP presence. Localization of the FSP and hydrogel within the ePTFE graft construct was assessed using fluorescently labeled polymers, and demonstrated hydrogel infiltration throughout the thickness of the graft wall, with FSP coating limited to the lumen and adventitial surfaces. FSP at the luminal surface on dual-coated grafts was able to bind endothelial cells (EC) (98.7 ± 23.1 cells/mm(2) ) similar to fibronectin controls (129.4 ± 40.7 cells/mm(2) ), and significantly higher than uncoated ePTFE (31.6 ± 19 cells/mm(2,) P < 0.05). These results indicate that ePTFE grafts can be simultaneously modified with two different polymers that have potential to directly address both endothelialization and intimal hyperplasia. Such a construct is a promising candidate for an off-the-shelf synthetic graft for small-diameter graft applications. © 2015 Wiley Periodicals, Inc.

  1. Tooth Movement out of the Bony Wall Using Augmented Corticotomy with Nonautogenous Graft Materials for Bone Regeneration

    OpenAIRE

    Kye-Bok Lee; Dong-Yeol Lee; Hyo-Won Ahn; Seong-Hun Kim; Eun-Cheol Kim; Igor Roitman

    2014-01-01

    This prospective randomized split-mouth study was performed to compare the effects of augmented corticotomy with those of different nonautogenous bone graft materials combined with orthodontic tooth movement in dogs. Decortication was performed on the buccal bone surface of 6 male beagle dogs that were randomly assigned to receive grafts of deproteinized bovine bone mineral, irradiated cortical bone, or synthetic bone. Immediate orthodontic force was applied to the second and third premolars ...

  2. Radiation Grafting for the Functionalization and Development of Smart Polymeric Materials.

    Science.gov (United States)

    Pino-Ramos, Víctor H; Ramos-Ballesteros, Alejandro; López-Saucedo, Felipe; López-Barriguete, Jesús E; Varca, Gustavo H C; Bucio, Emilio

    2016-10-01

    Gamma radiation has been shown particularly useful for the functionalization of surfaces with stimuli-responsive polymers. This method involves the formation of active sites (free radicals) onto the polymeric backbone as a result of the high-energy radiation exposition over the polymeric material. Thus, a microenvironment suitable for the reaction among monomer and/or polymer and the active sites is formed and then leading to propagation to form side-chain grafts. The modification of polymers using high-energy irradiation can be performed by the following methods: direct or simultaneous, pre-irradiation oxidative, and pre-irradiation. The most frequently used ones correspond to the pre-irradiation oxidative method as well as the direct one. Radiation-grafting has many advantages over other conventional methods because it does not require the use of catalyst nor additives to initiate the reaction and usually no changes on the mechanical properties with respect to the pristine polymeric matrix are observed. This chapter is focused on the synthesis of smart polymers and coatings obtained by the use of gamma radiation. In addition, the diverse applications of these materials in the biomedical area are also reported, with focus in drug delivery, sutures, and biosensors.

  3. Autologous Bone Marrow Mesenchymal Stem Cells Associated with Tantalum Rod Implantation and Vascularized Iliac Grafting for the Treatment of End-Stage Osteonecrosis of the Femoral Head

    Directory of Open Access Journals (Sweden)

    Dewei Zhao

    2015-01-01

    Full Text Available Tantalum rod implantation with vascularized iliac grafting has been reported to be an effective method for the treatment of young patients with osteonecrosis of the femoral head (ONFH to avert the need for total hip arthroplasty (THA. However, there have been unsatisfactory success rates for end-stage ONFH. The authors describe a modified technique using bone marrow mesenchymal stem cells (BMMSCs associated with porous tantalum rod implantation combined with vascularized iliac grafting for the treatment of end-stage ONFH. A total of 24 patients (31 hips with end-stage ONFH were treated with surgery; ARCO IIIc stage was observed in 19 hips and ARCO IV stage was observed in 12 hips. All patients were followed for a mean time of 64.35 ± 13.03 months (range 26–78. Operations on only five hips were converted to THA. The joint-preserving success rate of the entire group was 89.47% for ARCO stage IIIc and 75% for ARCO stage IV. The mean Harris hip score of the 31 hips improved significantly from 38.74 ± 5.88 points (range 22–50 to 77.23 ± 14.75 points (range 33–95. This intervention was safe and effective in delaying or avoiding total hip replacement for end-stage ONFH.

  4. Autologous Bone Marrow Mesenchymal Stem Cells Associated with Tantalum Rod Implantation and Vascularized Iliac Grafting for the Treatment of End-Stage Osteonecrosis of the Femoral Head

    Science.gov (United States)

    Zhao, Dewei; Liu, Baoyi; Wang, Benjie; Yang, Lei; Xie, Hui; Huang, Shibo; Zhang, Yao; Wei, Xiaowei

    2015-01-01

    Tantalum rod implantation with vascularized iliac grafting has been reported to be an effective method for the treatment of young patients with osteonecrosis of the femoral head (ONFH) to avert the need for total hip arthroplasty (THA). However, there have been unsatisfactory success rates for end-stage ONFH. The authors describe a modified technique using bone marrow mesenchymal stem cells (BMMSCs) associated with porous tantalum rod implantation combined with vascularized iliac grafting for the treatment of end-stage ONFH. A total of 24 patients (31 hips) with end-stage ONFH were treated with surgery; ARCO IIIc stage was observed in 19 hips and ARCO IV stage was observed in 12 hips. All patients were followed for a mean time of 64.35 ± 13.03 months (range 26–78). Operations on only five hips were converted to THA. The joint-preserving success rate of the entire group was 89.47% for ARCO stage IIIc and 75% for ARCO stage IV. The mean Harris hip score of the 31 hips improved significantly from 38.74 ± 5.88 points (range 22–50) to 77.23 ± 14.75 points (range 33–95). This intervention was safe and effective in delaying or avoiding total hip replacement for end-stage ONFH. PMID:25802840

  5. Treatment of neglected femoral neck fractures using the modified dynamic hip screw with autogenous bone and bone morphogenetic protein-2 composite materials grafting.

    Science.gov (United States)

    Lin, Dasheng; Zuo, Shenjia; Li, Lin; Wang, Lei; Lian, Kejian

    2015-01-01

    The neglected femoral neck fracture is one where there has been a delay of more than 30 days to seek medical help from the time of the original injury. Salvage procedures, such as osteotomy and other treatment options such as vascularized and nonvascularized bone grafts have high failure rates and arthroplasty procedures are not ideal, given the patient's young age and higher levels of activity. We designed a hollow bone graft dynamic hip screw (Hb-DHS) (modified DHS, Hb-DHS) for use in neglected femoral neck fractures. This study evaluates the efficacy and safety of the modified dynamic hip screw (DHS) with autogenous bone and bone morphogenetic protein 2 (BMP-2) composite materials grafting for the treatment of the neglected femoral neck fractures. A prospective study was carried out in twenty patients of neglected femoral neck fractures treated with the modified DHS with autogenous bone and BMP-2 composite materials grafting between July 2007 and February 2010. There were 14 men and 6 women with a mean age of 29.6 years (range 19-42 years). The mean time from injury to surgery was 9.7 weeks (range 6-16 weeks). The operation time, intraoperative blood loss, fracture healing time, Harris scoring for hip function and complications were recorded to evaluate treatment effects. The mean operation time was 75.8 min (range 55-100 min) with mean intraoperative blood loss volume of 105 mL (range 70-220 mL). The mean time to union was 17 weeks (range 12-24 weeks). One patient did not achieve union, and two patients had avascular necrosis of the femoral head. This patient with nonunion underwent intertrochanteric osteotomy. In patients with avascular necrosis one required total hip arthroplasty, the other did not require intervention at the last followup. A total of 14 patients (70%) had excellent results, 2 (10%) had good, 1 (5%) had moderate and 3 (15%) had poor results. The modified DHS with autogenous bone and BMP-2 composite materials grafting for the treatment of

  6. The effects of ozone on bacterial growth and thiol-disulphide homeostasis in vascular graft infection caused by MRSA in rats.

    Science.gov (United States)

    Ozturk, Barcin; Kurtoglu, Tunay; Durmaz, Selim; Kozaci, Leyla Didem; Abacigil, Filiz; Ertugrul, Bulent; Erel, Ozcan

    2017-03-01

    To investigate the microbiological, inflammatory and oxidant effects of adjuvant ozone administration in experimental rat vascular graft infection model which has not been previously investigated. Forty adult Wistar rats were divided into Sham, Control, Vancomycin, Ozone, Vancomycin+Ozone groups. Grafts were inoculated with Methicillin-resistant Staphylococcus aureus (MRSA) strain and implanted subcutaneously. Rats were treated intraperitoneally with ozone and /or intramuscularly with vancomycin for 10 days. Grafts were evaluated by quantitative bacterial cultures. Blood samples were harvested for determination of thiol-disulphide and cytokine profiles. There was no significant difference in bacterial counts between Control and Ozone Groups. In the Ozone Group median colony count was significantly higher than the Vancomycin and Vancomycin+Ozone Groups. Total thiol and disulphide levels increased and disulphide/native thiol and disulphide/total thiol ratios decreased in Ozone Group significantly. Albumin levels decreased significantly in Vancomycin and Vancomycin+Ozone Groups compared to the Sham Group. IL-1 and TNF-alpha levels significantly increased in infected rats. Decreased levels of VEGF due to infection reversed by ozone therapy in control and vancomycin groups. We didn't observe any benefit of the agent on MRSA elimination in our model. Likewise, effects of ozone on thiol-disulphide homeostasis and inflammatory cytokines were contradictory.

  7. New hybrid materials based on poly(ethyleneoxide-grafted polysilazane by hydrosilylation and their anti-fouling activities

    Directory of Open Access Journals (Sweden)

    Thi Dieu Hang Nguyen

    2013-10-01

    Full Text Available The objective of this work was to develop new coating materials based on poly(ethyleneoxide (PEO, which was grafted onto polysilazane (PSZ by hydrosilylation. Three types of PEO with different molecular weights (350, 750, 2000 g/mol were studied. The kinetics and yields of this reaction have been surveyed by 1H and 13C NMR spectroscopy. The PEO grafting-density onto PSZ by hydrosilylation increases with a reduction of the S–H/allyl ratio and a decrease of the PEO chain-length. The PEO-graft-PSZ (PSZ-PEO hybrid coatings, which can be used to prevent the adhesion of marine bacteria on surfaces, were applied by moisture curing at room temperature. The anti-adhesion performance, and thus the anti-fouling activity, of the coatings against three marine bacteria species, Clostridium sp. SR1, Neisseria sp. LC1 and Neisseria sp. SC1, was examined. The anti-fouling activity of the coatings depends on the grafting density and the chain length of PEO. The shortest PEO(350 g/mol-graft-PSZ with the highest graft density was found to have the best anti-fouling activity. As the density of grafted PEO(750 g/mol and PEO(2000 g/mol chains onto the PSZ surface is approximately equal, the relative effectiveness of these two types of PEO is controlled by the length of the PEO chain. The PEO(2000 g/mol-graft-PSZ coatings are more efficient than the PEO(750 g/mol-graft-PSZ coatings for the bacterial anti-adhesion.

  8. Using Polymeric Scaffolds for Vascular Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Alida Abruzzo

    2014-01-01

    Full Text Available With the high occurrence of cardiovascular disease and increasing numbers of patients requiring vascular access, there is a significant need for small-diameter (<6 mm inner diameter vascular graft that can provide long-term patency. Despite the technological improvements, restenosis and graft thrombosis continue to hamper the success of the implants. Vascular tissue engineering is a new field that has undergone enormous growth over the last decade and has proposed valid solutions for blood vessels repair. The goal of vascular tissue engineering is to produce neovessels and neoorgan tissue from autologous cells using a biodegradable polymer as a scaffold. The most important advantage of tissue-engineered implants is that these tissues can grow, remodel, rebuild, and respond to injury. This review describes the development of polymeric materials over the years and current tissue engineering strategies for the improvement of vascular conduits.

  9. Design, synthesis, and initial evaluation of D-glyceraldehyde crosslinked gelatin-hydroxyapatite as a potential bone graft substitute material

    Science.gov (United States)

    Florschutz, Anthony Vatroslav

    Utilization of bone grafts for the treatment of skeletal pathology is a common practice in orthopaedic, craniomaxillofacial, dental, and plastic surgery. Autogenous bone graft is the established archetype but has disadvantages including donor site morbidity, limited supply, and prolonging operative time. In order to avoid these and other issues, bone graft substitute materials are becoming increasingly prevalent among surgeons for reconstructing skeletal defects and arthrodesis applications. Bone graft substitutes are biomaterials, biologics, and guided tissue/bone regenerative devices that can be used alone or in combinations as supplements or alternatives to autogenous bone graft. There is a growing interest and trend to specialize graft substitutes for specific indications and although there is good rationale for this indication-specific approach, the development and utility of a more universal bone graft substitute may provide a better answer for patients and surgeons. The aim of the present research focuses on the design, synthesis, and initial evaluation of D-glyceraldehyde crosslinked gelatin-hydroxyapatite composites for potential use as a bone graft substitutes. After initial establishment of rational material design, gelatinhydroxyapatite scaffolds were fabricated with different gelatin:hydroxyapatite ratios and crosslinking concentrations. The synthesized scaffolds were subsequently evaluated on the basis of their swelling behavior, porosity, density, percent composition, mechanical properties, and morphology and further assessed with respect to cell-biomaterial interaction and biomineralization in vitro. Although none of the materials achieved mechanical properties suitable for structural graft applications, a reproducible material design and synthesis was achieved with properties recognized to facilitate bone formation. Select scaffold formulations as well as a subset of scaffolds loaded with recombinant human bone morphogenetic protein-2 were

  10. Dentin matrix gelatin (DMG) as a possible "universal" grafting material in periodontics.

    Science.gov (United States)

    Gould, T R; Westbury, L; Tillman, J

    1982-01-01

    The ideal of periodontal surgery is the total regeneration of the lost periodontal complex. A promising new osseous grafting material is Dental Matrix Gelation (DMG). DMG was prepared by a method similar to that of Conover and Urist (1979). This consisted of sequential extraction in 1:1 chloroform-methanol, 25 degrees C for 1 hour; 0.6 N HCl, 2 degrees C for 24 hours with constant agitation; 2 M CaCl2, 2 degrees C for 1 hour; 0.5 M EDTA pH 7.4, 2 degrees C for 1 hour; washed in distilled water 1 hour. Twelve rats were anesthetized, had heads shaved, midline flaps reflected, and 2 mm holes drilled through the right and left parietal bones. This type of osseous defect normally heals only by fibrous scarring and has been used to define osteoinductive materials. The DMG was cut into pieces about 1 mm square and placed into the right side defect while the left side remained open as a control. The animals were sacrificed on a schedule of two rats every 2 weeks until the 10th week when four rats were killed. The results showed complete osseous closure of the DMG site while the control healed by fibrous scarring. DMG seems to have strong osteoinductive power, and used allogenically has great potential as a commercially viable implant material.

  11. Medial opening-wedge high tibial osteotomy fixation with short plate without any graft, synthetic material or spacer.

    Science.gov (United States)

    Türkmen, Faik; Sever, Cem; Kacıra, Burkay K; Demirayak, Mehmet; Acar, Mehmet Ali; Toker, Serdar

    2014-12-01

    Medial opening-wedge high tibial osteotomy (MOWHTO) is an effective surgical procedure for patients who have medial compartmental osteoarthritis of the knee with varus deformity of the limb. The abnormal load on the medial compartment of the knee is directed to the lateral compartment with this procedure. A gap occurs on the proximal tibia while providing adequate correction. Filling this gap with bone grafts or synthetic materials has gained wide acceptance for preventing bone union problems or osteotomy site collapse. The aim of this study is to report our results of MOWHTOs performed without any bone graft or any other synthetic materials. We evaluated 41 MOWHTOs that have been performed between 2009 and 2012 with no use of any grafts or synthetic materials and spacer. Age of the patients ranged from 43 to 67. Thirty-five of the patients were females and three of them were males. The follow-up time was 6 months. Seven knees had opening at the osteotomy site 12.5 mm (range 7.5-14 mm, mean 11.07 mm). All osteotomies united without loss of correction. The mean bone union time was 12.8 weeks. We did not have any major complication regarding the technique. The results of our study have shown that we can achieve satisfactory and good results by performing MOWHTO procedure without using any bone grafts or synthetic materials and spacer.

  12. Medial Opening Wedge High Tibial Osteotomy Fixation with Short Plate without any Graft, Synthetic Material or Spacer

    Science.gov (United States)

    Türkmen, Faik; Sever, Cem; Kacıra, Burkay Kutluhan; Demirayak, Mehmet; Acar, Mehmet Ali; Toker, Serdar

    2014-01-01

    Objectives: Medial opening-wedge high tibial osteotomy (MOWHTO) is an effective surgical procedure for patients who have medial compartmental osteoarthritis of the knee with varus deformity of the limb. The abnormal load on the medial compartment of the knee relocates to the lateral compartment with this procedure. A gap occurs on the proximal tibia during the correction of varus deformity. Filling this gap with bone grafts or synthetic materials has gained wide acceptance for preventing nonunion or osteotomy site collapse. The aim of this study is to report our results of MOWHTOs performed without any bone graft or any other synthetic materials. Methods: We evaluated 41 MOWHTOs performed between 2009 and 2012 with no use of bone grafts, synthetic materials or spacers. Age of the patients ranged from 43 to 67. Thirty five of the patients were female and 3 of them were male. The follow-up time was 6 months. Results: There were no any non-unions or loss of correction. The mean bone union time was 12,8 weeks. No major complications were seen. Conclusion: The results of our study has shown that achieve satisfactory results can be obtained in MOWHTO without using any bone graft, synthetic materials or spacer.

  13. CBCT fine preoperative evaluation of inflammatory radicular cysts and postoperative local integration appreciation of alloplastic grafts materials.

    Science.gov (United States)

    Nica, Diana; Ianes, Emilia; Brad, S

    2014-01-01

    The purpose of this paper is to point out the value of CBCT exam in pre and postoperative diagnosis assessment of inflammatory radicular cysts together with full appreciation of local integration of alloplastic graft materials used to repair the osseous defects. There were statistically retrospective evaluated the pre and postoperative results of CBCT and x-ray examinations of 34 patients with inflammatory radicular cysts clinically, biologically and histopathologically assessed at Oral and Maxilo-Facial Surgery Clinic from Timisoara. In all cases we proceeded to surgical radicular cysts removement, extraction of the associated non-vital tooth together with alloplastic graft materials repairement of the osseous defects. The CBCT preoperative scans clearly showed the extent, the morphological characteristics and the topoanatomic reports, in all 34 cases of inflammatory radicular cysts together with regional endodontic status. The CBCT postoperative scans revealed the very local integration of alloplastic graft materials used to repair the osseous defects and, in some cases, the dental rehabilitation by metallic implants. CBCT scan is the imaging method of choice in pre and postoperative diagnosis assessment of inflammatory radicular cysts together with alloplastic graft materials repairement of the osseous defects and dental rehabilitation by metallic implants, due to high specific abilities in bone tissue 3D evaluation.

  14. Heparin and Vascular Endothelial Growth Factor Loaded Poly(L-lactide-co-caprolactone) Nanofiber Covered Stent-Graft for Aneurysm Treatment.

    Science.gov (United States)

    Wang, Jing; An, Qingzhu; Li, Dawei; Wu, Tong; Chen, Weiming; Sun, Binbin; El-Hamshary, Hany; Al-Deyab, Salem S; Zhu, Wei; Mo, Xiumei

    2015-11-01

    Restenosis caused by thrombopoiesis is one of the biggest hinders of endovascular stent-graft used in small-diameter vessels. Rapid endothelialization of the lumen of stent is a promising approach to prevent thrombosis. In this study, we aimed at loading heparin, a potent anticoagulants, and vascular endothelial growth factor (VEGF) into the core of poly(L-lactide-co-caprolactone) nanofiber via emulsion electrospinning. The nanofiber was covered on the stent and applied in the treatment of vascular diseases such as aneurysm. The morphologies of the emulsion electrospun nanofibers and core--shell structure were observed by scanning electron microscope and laser scanning confocal microscope. The release profiles of heparin and VEGF, degradation rate of nanofiber mats and cell proliferation in vitro were investigated. It was found that the release of both heparin and VEGF from the nanofiber lasted for more than 30 days without serious initial burst release. The degradation rate of nanofiber mats containing heparin and VEGF was faster than that of pure PLCL nanofiber mats. Moreover, the released VEGF could promote the proliferation of Pig iliac endothelial cells (PIECs) cultured on the nanofiber mat, which was of great benefit to stent endothelialization. The results of digital subtraction angiography (DSA) follow-up indicated the aneurysm was obliterated by separating the aneurysm dome from the blood circulation and the parent artery kept long-term patency. Results of the study demonstrated that the heparin and VEGF loaded nanofiber could provide an approach to fabricate covered stent-graft with properties of anticoagulation and induction of rapid endothelialization.

  15. Long-term animal implantation study of biotube-autologous small-caliber vascular graft fabricated by in-body tissue architecture.

    Science.gov (United States)

    Watanabe, Taiji; Kanda, Keiichi; Yamanami, Masashi; Ishibashi-Ueda, Hatsue; Yaku, Hitoshi; Nakayama, Yasuhide

    2011-07-01

    A mold for the preparation of an in-body tissue architecture-induced autologous vascular graft, termed "biotube," was prepared by covering a main silicone rod (outer diameter, 3 mm; length, 30 mm) with two pieces of polyurethane sponge tubes (internal diameter, 3 mm; length, 3 mm) at both ends. The molds were embedded into the dorsal subcutaneous pouch of rabbits (weighing ca. 2 kg) for 2 months. After harvesting the rods with the formed surrounding tissues, the rods were removed to create biotubes impregnated with anastomotic reinforcement cuffs at both ends. The biotubes had homogeneous, thin connective tissue wall (thickness, 76 ± 37 μm) that was primarily composed of collagen and fibroblasts. One biotube was loaded with argatroban and autoimplanted in the carotid artery for 26 months. Neither antiplatelet nor anticoagulant agents were administered, except for an intraoperative heparin injection. Follow-up angiography showed no aneurysm formation, rupturing, or stenosis during implantation. At the end of implantation, the wall thickness of biotube (212 ± 24 μm at the anastomosis portion and 150 ± 14 μm at the midportion) was similar to that of native artery (189 ± 23 μm). The luminal surface was completely covered with endothelial cells on the formed lamina elastica interna-like layer. The regenerated vascular walls comprised multilayered smooth muscle cells and dense collagen fibers with regular circumferential orientation. A remarkable multilayered elastin fiber network was observed near the anastomosis portion. Biotubes could thus be used as small-caliber vascular prostheses that greatly facilitate the healing process and exhibit excellent biocompatibility. Copyright © 2011 Wiley Periodicals, Inc.

  16. Comparison of arteriovenous fistulas and arteriovenous grafts in patients with favorable vascular anatomy and equivalent access to health care: is a reappraisal of the Fistula First Initiative indicated?

    Science.gov (United States)

    Disbrow, David E; Cull, David L; Carsten, Christopher G; Yang, Seung Koo; Johnson, Brent L; Keahey, Gail P

    2013-04-01

    Initiatives to increase arteriovenous fistula (AVF) use are based on studies that show that AVFs require fewer interventions and have better patency than arteriovenous grafts (AVGs). Because patients who receive AVFs typically have more favorable vascular anatomy and are referred earlier for access placement than those who receive AVGs, the advantages of AVF might be overestimated. We compared outcomes for AVFs and AVGs in patients with equivalent vascular anatomy who were on dialysis via catheter at the time of vascular access placement. The study included patients who underwent placement of a first-time AVF or AVG between 2006 and 2009, who were on dialysis via catheter at the time of access placement, and who had favorable arterial and venous (>3 mm) anatomy. Outcomes for AVF and AVG were compared. Eighty-nine AVF and 59 AVG patients met study inclusion criteria. Similar secondary patency was achieved by AVG and AVF at 12 (72% vs 71%) and 24 months (57% vs 62%), respectively (p = 0.96). The number of interventions required to maintain patency for AVF (n = 1; range 0 to 10) and AVG (n = 1; range 0 to 11) were not different (p = 0.36). However, the number of catheter days to first access use was more than doubled in the AVF group (median 81 days) compared with the AVG group (median 38 days; p functional AVF can negate its benefits over AVG. A fistula first approach might not always apply to patients who are already on dialysis when referred for chronic access placement. Copyright © 2013 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  17. Expression of BMP-2 in Vascular Endothelial Cells of Recipient May Predict Delayed Graft Function After Renal Transplantation.

    Science.gov (United States)

    Basic-Jukic, Nikolina; Gulin, Marijana; Hudolin, Tvrtko; Kastelan, Zeljko; Katalinic, Lea; Coric, Marijana; Veda, Marija Varnai; Ivkovic, Vanja; Kes, Petar; Jelakovic, Bojan

    2016-01-01

    Delayed graft function (DGF) is associated with adverse outcomes after renal transplantation. Bone morphogenetic protein-2 (BMP-2) is involved in both endothelial function and immunological events. We compared expression of BMP-2 in epigastric artery of renal transplant recipients with immediate graft function (IGF) and DGF. 79 patients were included in this prospective study. Patients were divided in IGF group (64 patients) and DGF group (15 patients). BMP-2 expression in intima media (BMP2m) and endothelium (BMP2e) of epigastric artery was assessed by immunohistochemistry. Lower intensity of BMP2e staining was recorded in DGF compared to IGF. In DGF patients, 93% had no expression of BMP2e and 7% had 1st grade expression, compared to 45% and 41% in IGF group, respectively (P=0.001) (P<0.001 for no expression and P = 0.015 for 1st grade expression). Patients who had BMP2e staining positive had lower odds for DGF (OR 0.059 [0.007, 0.477]) and this remained significant even after adjustment for donor and recipient variables, cold ischemia time, and immunological matching (OR 0.038 [0.003, 0.492]). Our results demonstrate that BMP-2 expression in endothelial cells of epigastric arteries may predict development of DGF. © 2016 The Author(s) Published by S. Karger AG, Basel.

  18. Expression of BMP-2 in Vascular Endothelial Cells of Recipient May Predict Delayed Graft Function After Renal Transplantation

    Directory of Open Access Journals (Sweden)

    Nikolina Basic-Jukic

    2016-11-01

    Full Text Available Background/Aims: Delayed graft function (DGF is associated with adverse outcomes after renal transplantation. Bone morphogenetic protein-2 (BMP-2 is involved in both endothelial function and immunological events. We compared expression of BMP-2 in epigastric artery of renal transplant recipients with immediate graft function (IGF and DGF. Methods: 79 patients were included in this prospective study. Patients were divided in IGF group (64 patients and DGF group (15 patients. BMP-2 expression in intima media (BMP2m and endothelium (BMP2e of epigastric artery was assessed by immunohistochemistry. Results: Lower intensity of BMP2e staining was recorded in DGF compared to IGF. In DGF patients, 93% had no expression of BMP2e and 7% had 1st grade expression, compared to 45% and 41% in IGF group, respectively (P=0.001 (Pst grade expression. Patients who had BMP2e staining positive had lower odds for DGF (OR 0.059 [0.007, 0.477] and this remained significant even after adjustment for donor and recipient variables, cold ischemia time, and immunological matching (OR 0.038 [0.003, 0.492]. Conclusions: Our results demonstrate that BMP-2 expression in endothelial cells of epigastric arteries may predict development of DGF.

  19. VEGF-releasing suture material for enhancement of vascularization: development, in vitro and in vivo study.

    Science.gov (United States)

    Bigalke, Christian; Luderer, Frank; Wulf, Katharina; Storm, Thilo; Löbler, Marian; Arbeiter, Daniela; Rau, Bettina M; Nizze, Horst; Vollmar, Brigitte; Schmitz, Klaus-Peter; Klar, Ernst; Sternberg, Katrin

    2014-12-01

    As it has been demonstrated that bioactive substances can be delivered locally using coated surgical suture materials, the authors developed a vascular endothelial growth factor (VEGF)-releasing suture material that should promote vascularization and potentially wound healing. In this context, the study focused on the characterization of the developed suture material and the verification of its biological activity, as well as establishing a coating process that allows reproducible and stable coating of a commercially available polydioxanone suture material with poly(l-lactide) (PLLA) and 0.1μg and 1.0μg VEGF. The in vitro VEGF release kinetics was studied using a Sandwich ELISA. The biological activity of the released VEGF was investigated in vitro using human umbilical vein endothelial cells. The potential of the VEGF-releasing suture material was also studied in vivo 5days after implantation in the hind limb of Wistar rats, when the histological findings were analyzed. The essential results, enhanced cell viability in vitro as well as significantly increased vascularization in vivo, were achieved using PLLA/1.0μg VEGF-coated suture material. Furthermore, ELISA measurements revealed a high reproducibility of the VEGF release behavior. Based on the results achieved regarding the dose-effect relationship of VEGF, the stability during its processing and the release behavior, it can be predicted that a bioactive suture material would be successful in later in vivo studies. Therefore, this knowledge could be the basis for future studies, where bioactive substances with different modes of action are combined for targeted, overall enhancement of wound healing. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  20. Cytocompatibility and biologic characteristics of synthetic scaffold materials of rabbit acellular vascular matrix combining with human-like collagen I.

    Science.gov (United States)

    Liu, Xuqian; Wang, Jie; Dong, Fusheng; Song, Peng; Tian, Songbo; Li, Hexiang; Hou, Yali

    2017-10-01

    Scaffold material provides a three-dimensional growing environment for seed cells in the research field of tissue engineering. In the present study, rabbit arterial blood vessel cells were chemically removed with trypsin and Triton X-100 to prepare rabbit acellular vascular matrix scaffold material. Observation by He&Masson staining revealed that no cellular components or nuclei existed in the vascular intima and media after decellularization. Human-like collagen I was combined with acellular vascular matrix by freeze-drying to prepare an acellular vascular matrix-0.25% human-like collagen I scaffold to compensate for the extracellular matrix loss during the decellularization process. We next performed a series of experiments to test the water absorbing quality, biomechanics, pressure resistance, cytotoxicity, and ultra-micro structure of the acellular vascular matrix composite material and natural rabbit artery and found that the acellular vascular matrix-0.25% human-like collagen I material behaved similarly to natural rabbit artery. In conclusion, the acellular vascular matrix-0.25% human-like collagen I composite material provides a new approach and lays the foundation for novel scaffold material research into tissue engineering of blood vessels.

  1. Polyethyleneimine-grafted boronate affinity materials for selective enrichment of cis-diol-containing compounds.

    Science.gov (United States)

    Xue, Yun; Shi, Wenjun; Zhu, Bangjie; Gu, Xue; Wang, Yan; Yan, Chao

    2015-08-01

    Polyethyleneimine (PEI)-grafted and 3-acrylamidophenylboronic acid (AAPBA)-functionalized SiO2 boronate affinity materials were synthesized for the selective enrichment of cis-diol-containing compounds. Characterization results of scanning electron microscopy, Fourier transform infrared spectroscopy, elemental analysis, zeta potential, and X-ray photoelectron spectroscopy indicated the successful fabrication of SiO2@PEI-AAPBA materials. Chromatographic separation of test mixtures reveals that SiO2@PEI-AAPBA has high selective enrichment ability for cis-diol-containing compounds. The binding pH between SiO2@PEI-AAPBA and catechol was found to be as low as pH 4.5, while that between SiO2@PEI-AAPBA and adenosine was only ~7.5. This difference might be attributed to the strong electrostatic repulsion between the solid phase and analytes at a low pH. Furthermore, a diphasic separation column was fabricated based on boronate affinity chromatography, C18-reversed-phase chromatography and applied in pressurized capillary electrochromatography (pCEC). Results showed that four polar nucleosides could be well captured by the boronate affinity chromatography (BAC) section and separated by reversed phase pCEC. Finally, SiO2@PEI600-AAPBA-based solid-phase extraction technology was applied to the purification of ribonucleosides in real urine samples, and results of UHPLC-MS/MS revealed that the intensities of the extracted ions (a neutral mass loss of m/z 132.04 Da) of the ribonucleosides were significantly enhanced after the enrichment. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Review of Mechanical Testing and Modelling of Thrombus Material for Vascular Implant and Device Design.

    Science.gov (United States)

    Johnson, S; Duffy, S; Gunning, G; Gilvarry, M; McGarry, J P; McHugh, P E

    2017-08-28

    A thrombus or blood clot is a solid mass, made up of a network of fibrin, platelets and other blood components. Blood clots can form through various pathways, for example as a result of exposed tissue factor from vascular injury, as a result of low flow/stasis, or in very high shear flow conditions. Embolization of cardiac or vascular originating blood clots, causing an occlusion of the neurovasculature, is the major cause of stroke and accounts for 85% of all stroke. With mechanical thrombectomy emerging as the new standard of care in the treatment of acute ischemic stroke (AIS), the need to generate a better understanding of the biomechanical properties and material behaviour of thrombus material has never been greater, as it could have many potential benefits for the analysis and performance of these treatment devices. Defining the material properties of a thrombus has obvious implications for the development of these treatment devices. However, to-date this definition has not been adequately established. While some experimentation has been performed, model development has been extremely limited. This paper reviews the previous literature on mechanical testing of thrombus material. It also explores the use of various constitutive and computational models to model thrombus formation and material behaviour.

  3. Guar gum-grafted poly(acrylonitrile)-templated silica xerogel: nanoengineered material for lead ion removal

    National Research Council Canada - National Science Library

    Pandey, Sadanand; Ramontja, James

    2016-01-01

    .... Aside from this Saponification guar-graft-polyacrylonitrile (s-GG-g-PAN) as a copolymer are included in the precursor solution for providing a novel templating environment for silica matrix formation...

  4. Time and materials needed to survey, inject systemic fungicides, and install root-graft barriers for Dutch elm disease management

    Science.gov (United States)

    William N., Jr. Cannon; Jack H. Barger; Charles J. Kostichka; Charles J. Kostichka

    1986-01-01

    Dutch elm disease control practice in 15 communities showed a wide range of time and material required to apply control methods. The median time used for each method was: sanitation survey, 9.8 hours per square mile; symptom survey, 96 hours per thousand elms; systemic fungicide injection, 1.4 hours per elm; and root-graft barrier installation, 2.2 hours per barrier (5...

  5. Wear of carbon nanotubes grafted on carbon fibers and this influence on the properties of composites materials

    Science.gov (United States)

    Guignier, Claire; Bueno, Marie-Ange; Camillieri, Brigitte; Durand, Bernard

    2017-10-01

    Carbon nanotubes (CNTs) grafted on carbon surfaces can be used to reinforce composite materials. During an industrial process of CNTs production and composite processing, friction stresses will be applied on CNTs. This study showed that CNTs formed a transfer film under friction stresses and that the wear of the CNTs has no influence on the wettability of the surface, so we can predict no decrease in the properties of composites.

  6. Cutaneous chronic graft-versus-host disease does not have the abnormal endothelial phenotype or vascular rarefaction characteristic of systemic sclerosis.

    Directory of Open Access Journals (Sweden)

    Jo Nadine Fleming

    2009-07-01

    Full Text Available The clinical and histologic appearance of fibrosis in cutaneous lesions in chronic graft-versus -host disease (c-GVHD resembles the appearance of fibrosis in scleroderma (SSc. Recent studies identified distinctive structural changes in the superficial dermal microvasculature and matrix of SSc skin. We compared the dermal microvasculature in human c-GVHD to SSc to determine if c-GVHD is a suitable model for SSc.We analyzed skin biopsies of normal controls (n = 24, patients with SSc (n = 30 and c-GVHD with dermal fibrosis (n = 133. Immunostaining was employed to identify vessels, vascular smooth muscle, dermal matrix, and cell proliferation. C-GVHD and SSc had similar dermal matrix composition and vascular smooth muscle pathology, including intimal hyperplasia. SSc, however, differed significantly from c-GVHD in three ways. First, there were significantly fewer (p = 0.00001 average vessels in SSc biopsies (9.8 when compared with c-GVHD (16.5. Second, in SSc, endothelial markers were decreased significantly (19/19 and 12/14 for VE cadherin and vWF (p = <0.0001 and <0.05, respectively. In contrast, 0/13 c-GVHD biopsies showed loss of staining with canonical endothelial markers. Third, c-GVHD contained areas of microvascular endothelial proliferation not present in the SSc biopsies.The sclerosis associated with c-GVHD appears to resemble wound healing. Focal capillary proliferation occurs in early c-GVHD. In contrast, loss of canonical endothelial markers and dermal capillaries is seen in SSc, but not in c-GVHD. The loss of VE cadherin in SSc, in particular, may be related to microvascular rarefaction because VE cadherin is necessary for angiogenesis. C-GVHD is a suitable model for studying dermal fibrosis but may not be applicable for studying the microvascular alterations characteristic of SSc.

  7. In vitro fabrication of autologous living tissue-engineered vascular grafts based on prenatally harvested ovine amniotic fluid-derived stem cells.

    Science.gov (United States)

    Weber, Benedikt; Kehl, Debora; Bleul, Ulrich; Behr, Luc; Sammut, Sébastien; Frese, Laura; Ksiazek, Agnieszka; Achermann, Josef; Stranzinger, Gerald; Robert, Jérôme; Sanders, Bart; Sidler, Michele; Brokopp, Chad E; Proulx, Steven T; Frauenfelder, Thomas; Schoenauer, Roman; Emmert, Maximilian Y; Falk, Volkmar; Hoerstrup, Simon P

    2016-01-01

    Amniotic fluid cells (AFCs) have been proposed as a valuable source for tissue engineering and regenerative medicine. However, before clinical implementation, rigorous evaluation of this cell source in clinically relevant animal models accepted by regulatory authorities is indispensable. Today, the ovine model represents one of the most accepted preclinical animal models, in particular for cardiovascular applications. Here, we investigate the isolation and use of autologous ovine AFCs as cell source for cardiovascular tissue engineering applications. Fetal fluids were aspirated in vivo from pregnant ewes (n = 9) and from explanted uteri post mortem at different gestational ages (n = 91). Amniotic non-allantoic fluid nature was evaluated biochemically and in vivo samples were compared with post mortem reference samples. Isolated cells revealed an immunohistochemical phenotype similar to ovine bone marrow-derived mesenchymal stem cells (MSCs) and showed expression of stem cell factors described for embryonic stem cells, such as NANOG and STAT-3. Isolated ovine amniotic fluid-derived MSCs were screened for numeric chromosomal aberrations and successfully differentiated into several mesodermal phenotypes. Myofibroblastic ovine AFC lineages were then successfully used for the in vitro fabrication of small- and large-diameter tissue-engineered vascular grafts (n = 10) and cardiovascular patches (n = 34), laying the foundation for the use of this relevant pre-clinical in vivo assessment model for future amniotic fluid cell-based therapeutic applications. Copyright © 2013 John Wiley & Sons, Ltd.

  8. Polymethacrylic acid grafted psyllium (Psy- g-PMA): a novel material for waste water treatment

    Science.gov (United States)

    Kumar, Ranvijay; Sharma, Kaushlendra; Tiwary, K. P.; Sen, Gautam

    2013-03-01

    Polymethacrylic acid grafted psyllium (Psy- g-PMA) was synthesized by microwave assisted method, which involves a microwave irradiation in synergism with silver sulfate as a free radical initiator to initiate grafting reaction. Psy- g-PMA grades have been synthesized and characterized on structural basis (elemental analysis, FTIR spectroscopy, intrinsic viscosity study) as well as morphological and thermal studies, taking psyllium as reference. The effects of reaction time, amount of monomer and silver sulfate (free radical initiator) on grafting of PMA on psyllium backbone have been studied. It is observed that all the grades of Psy- g-PMA have higher intrinsic viscosities than that of psyllium. The best synthesized grade was Psy- g-PMA having intrinsic viscosity of 6.93 and 58 % grafting of PMA on the main polymer backbone. Further Psy- g-PMA applications as flocculants for waste water treatment have been investigated. Psy- g-PMA resulted in higher decrease in the flocculation parameters such as total dissolved solid or total solids compared to psyllium. Hence the result shows the possible application of grafted psyllium in wastewater treatment.

  9. Albumen Glue, New Material for Conjunctival Graft Surgery, an Animal Experiment

    Science.gov (United States)

    Kartiwa, A.; Miraprahesti, R.; Sovani, I.; Enus, S.; Boediono, A.

    2017-02-01

    Attach conjunctival graft commonly used are suture technique and fibrin glue. This study was to investigate albumen glue as an alternative to suture technique in attaching conjunctival graft in rabbits. Aim of this study was to compare the conjunctival wound healing between albumen glue and suture technique in rabbit eye as a model. There was an experimental animal study included 32 eyes (16 rabbits) in PT. Bio Farma (Persero) and Histology Laboratory, Faculty of Medicine, Padjadjaran University from March 2014 to July 2104. The study consisted of albumen glue group and suture technique group. The examination included the comparison of conjunctival graft attachment and histologic examination by microscopically was done to obtain the wound gap, then analyze by Mann-Whitney test. The results indicated that the graft attachment was significantly better-using albumen glue (grade 4) compared to suture (grade 2-3) on day-1 after surgery (p=0,000). The wound gap was smaller using albumen glue (0-0,33 μm versus 5,33-14 μm ; p=0,0005) on 10 minutes after surgery and 0 μm versus 0,33-4 μm ; p=0,0005 on day-7 after surgery. In conclusion, the graft attachment using albumen glue was better and the wound gap was smaller using albumen glue than suture technique.

  10. Tooth Movement out of the Bony Wall Using Augmented Corticotomy with Nonautogenous Graft Materials for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Kye-Bok Lee

    2014-01-01

    Full Text Available This prospective randomized split-mouth study was performed to compare the effects of augmented corticotomy with those of different nonautogenous bone graft materials combined with orthodontic tooth movement in dogs. Decortication was performed on the buccal bone surface of 6 male beagle dogs that were randomly assigned to receive grafts of deproteinized bovine bone mineral, irradiated cortical bone, or synthetic bone. Immediate orthodontic force was applied to the second and third premolars for buccal tipping for 6 weeks. The pocket depth and width of keratinized tissue (WKT were measured. Histologic and histomorphometric analyses were performed. The probing depth, WKT, and ratio of the area of new bone to that of total bone on the buccal side were not significantly different between groups. All groups had considerable new bone formation on the pressure side. New bone formation on the buccal side and buccal plate formation in the coronal direction along the root surfaces were induced by the bone-derived and PDL-derived mesenchymal matrix, respectively. The angular change between groups was significantly different (P < 0.001. Augmented corticotomy using nonautogenous graft materials facilitated tooth movement without fenestrations and accelerated new bone formation on the pressure side.

  11. Phenolic resin-grafted reduced graphene oxide as a highly stable anode material for lithium ion batteries.

    Science.gov (United States)

    Li, Mochen; Song, Huaihe; Chen, Xiaohong; Zhou, Jisheng; Ma, Zhaokun

    2015-02-07

    A novel and effective route for preparing phenol formaldehyde resin grafted reduced graphene oxide (rGO-g-PF) electrode materials with highly enhanced electrochemical properties is reported. In order to prepare rGO-g-PF, hydroxymethyl-terminated PF is initially grafted to graphene oxide (GO) via esterification reaction. Subsequently, the grafted GO is reduced by the carbonization process under an inert gas atmosphere. The covalent linkage, morphology, thermal stability and electrochemical properties of rGO-g-PF are systematically investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, thermal gravimetric analysis, differential scanning calorimetry and a variety of electrochemical testing techniques. In the constructed architecture, the amorphous carbon shell can inhibit the co-intercalation of solvated lithium ion and avoid partial exfoliation of the graphene layers, thus effectively reducing the irreversible capacity and preserving the structural integrity. Meanwhile, the carbon coating layer leading to a decreased thickness of SEI film can improve the conductivity of electrode materials. As a result, the rGO-g-PF electrode exhibits impressive high cycling stability at various large current densities (376.5 mA h g(-1) at 50 mA g(-1) for 250 cycles, 337.8 mA h g(-1) at 200 mA g(-1) and 267.8 mA h g(-1) at 1 A g(-1) for 200 cycles), in combination with high rate capability.

  12. Cysteine-grafted nonwoven geotextile: a new and efficient material for heavy metals sorption--part A.

    Science.gov (United States)

    Vandenbossche, M; Casetta, M; Jimenez, M; Bellayer, S; Traisnel, M

    2014-01-01

    Cysteine is an interesting biomolecule in the heavy metals trapping field, thanks to its amino, thiol and carboxylic groups. This amino acid is indeed present in some natural chelating agents: glutathione, phytochelatins and metallothioneins. However, cysteine has never been used in remediation processes. When immobilized on a polypropylene nonwoven (PP) geotextile, an innovative and eco-friendly material is obtained, with potential use in drainage and filtration of wastewaters and sediments. PP was first functionalized with acrylic acid using a low pressure cold plasma process to bring reactive carboxylic functions onto the surface (PP-g-AA). Cysteine was then covalently grafted on this modified PP. The cysteine grafting on PP-g-AA was optimized using response surface methodology, which allowed concluding that the best conditions of immersion without heating consist in: a solution containing 0.229 mol/L of cysteine for 28 h. The materials were characterized by Scanning Electron Microscopy, InfraRed Spectroscopy and X-ray Photoelectron Spectroscopy: evidence of covalent cysteine grafting was given. Preliminary sorption tests at 20 °C and pH = 4.5 with artificially polluted solutions give promising results for divalent heavy metal ions: 95 mg Cu (II) (CuSO4 solution), 104 mg Cu (II) and 135 mg Pb(II) (with NO3(-) counter-ion) per gram of PP are trapped. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Role of mechanical compression on bone regeneration around a particulate bone graft material: an experimental study in rabbit calvaria.

    Science.gov (United States)

    Romanos, Georgios E; Delgado-Ruiz, Rafael A; Gómez-Moreno, Gerardo; López-López, Patricia J; Mate Sanchez de Val, Jose E; Calvo-Guirado, Jose Luis

    2015-04-12

    This experimental study was designed to analyze the effect of different compressive forces on the bone regeneration around a particulate bone graft material. Eighty 6-mm-diameter defects were created in the calvaria of 20 New Zealand rabbits (4 defects per rabbit calvaria). All the defects were filled with particles of synthetic bone. Two standardized compressive forces were then applied, 4.1 g to half the defects (Test A) and 8.2 g to the other half (Test B), all for 1 min. The graft sites were allowed to heal for 6 weeks, after which the rabbits were euthanized. The calvarium vault of each animal was extracted, radiographed, and prepared for histomorphometric analysis. The percentage of defect fill, bone density, new bone formation, and residual bone graft material were recorded, and the results were subjected to statistical analysis. Histological evaluation found that defect closure among the Test A (lower compression) group ranged from 38.34 (95% lower CI) to 55.8 (95% upper CI) (mean 47 ± 8.5%), while among the Test B group (higher compression), it ranged from 81.26 (95% lower CI) to 95.32 (mean 88 ± 7.3%). Significantly more closure was achieved for the Test B group (P particulate used to fill small defects created in rabbit calvaria appears to be beneficial. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Renal posttransplant's vascular complications

    Directory of Open Access Journals (Sweden)

    Bašić Dragoslav

    2003-01-01

    Full Text Available INTRODUCTION Despite high graft and recipient survival figures worldwide today, a variety of technical complications can threaten the transplant in the postoperative period. Vascular complications are commonly related to technical problems in establishing vascular continuity or to damage that occurs during donor nephrectomy or preservation [13]. AIM The aim of the presenting study is to evaluate counts and rates of vascular complications after renal transplantation and to compare the outcome by donor type. MATERIAL AND METHODS A total of 463 kidneys (319 from living related donor LD and 144 from cadaveric donor - CD were transplanted during the period between June 1975 and December 1998 at the Urology & Nephrology Institute of Clinical Centre of Serbia in Belgrade. Average recipients' age was 33.7 years (15-54 in LD group and 39.8 (19-62 in CD group. Retrospectively, we analyzed medical records of all recipients. Statistical analysis is estimated using Hi-squared test and Fischer's test of exact probability. RESULTS Major vascular complications including vascular anastomosis thrombosis, internal iliac artery stenosis, internal iliac artery rupture obliterant vasculitis and external iliac vein rupture were analyzed. In 25 recipients (5.4% some of major vascular complications were detected. Among these cases, 22 of them were from CD group vs. three from LD group. Relative rate of these complications was higher in CD group vs. LD group (p<0.0001. Among these complications dominant one was vascular anastomosis thrombosis which occurred in 18 recipients (17 from CD vs. one from LD. Of these recipients 16 from CD lost the graft, while the rest of two (one from each group had lethal outcome. DISCUSSION Thrombosis of renal allograft vascular anastomosis site is the most severe complication following renal transplantation. In the literature, renal allograft thrombosis is reported with different incidence rates, from 0.5-4% [14, 15, 16]. Data from the

  15. Hydroxyapatite grafted carbon nanotubes and graphene nanosheets: promising bone implant materials.

    Science.gov (United States)

    Oyefusi, Adebola; Olanipekun, Opeyemi; Neelgund, Gururaj M; Peterson, Deforest; Stone, Julia M; Williams, Ebonee; Carson, Laura; Regisford, Gloria; Oki, Aderemi

    2014-11-11

    In the present study, hydroxyapatite (HA) was successfully grafted to carboxylated carbon nanotubes (CNTs) and graphene nanosheets. The HA grafted CNTs and HA-graphene nanosheets were characterized using FT-IR, TGA, SEM and X-ray diffraction. The HA grafted CNTs and graphene nanosheets (CNTs-HA and Gr-HA) were further used to examine the proliferation and differentiation rate of temperature-sensitive human fetal osteoblastic cell line (hFOB 1.19). Total protein assays and western blot analysis of osteocalcin expression were used as indicators of cell proliferation and differentiation. Results indicated that hFOB 1.19 cells proliferate and differentiate well in treatment media containing CNTs-HA and graphene-HA. Both CNTs-HA and graphene-HA could be promising nanomaterials for use as scaffolds in bone tissue engineering. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Bone grafting: An overview

    Directory of Open Access Journals (Sweden)

    D. O. Joshi

    2010-08-01

    Full Text Available Bone grafting is the process by which bone is transferred from a source (donor to site (recipient. Due to trauma from accidents by speedy vehicles, falling down from height or gunshot injury particularly in human being, acquired or developmental diseases like rickets, congenital defects like abnormal bone development, wearing out because of age and overuse; lead to bone loss and to replace the loss we need the bone grafting. Osteogenesis, osteoinduction, osteoconduction, mechanical supports are the four basic mechanisms of bone graft. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. An ideal bone graft material is biologically inert, source of osteogenic, act as a mechanical support, readily available, easily adaptable in terms of size, shape, length and replaced by the host bone. Except blood, bone is grafted with greater frequency. Bone graft indicated for variety of orthopedic abnormalities, comminuted fractures, delayed unions, non-unions, arthrodesis and osteomyelitis. Bone graft can be harvested from the iliac crest, proximal tibia, proximal humerus, proximal femur, ribs and sternum. By adopting different procedure of graft preservation its antigenicity can be minimized. The concept of bone banking for obtaining bone grafts and implants is very useful for clinical application. Absolute stability require for successful incorporation. Ideal bone graft must possess osteogenic, osteoinductive and osteocon-ductive properties. Cancellous bone graft is superior to cortical bone graft. Usually autologous cancellous bone graft are used as fresh grafts where as allografts are employed as an alloimplant. None of the available type of bone grafts possesses all these properties therefore, a single type of graft cannot be recomm-ended for all types of orthopedic abnormalities. Bone grafts and implants can be selected as per clinical problems, the equipments available and preference of

  17. Spectroscopic Investigation of the Canopy Configurations in Nanoparticle Organic Hybrid Materials of Various Grafting Densities during CO 2 Capture

    KAUST Repository

    Petit, Camille

    2012-01-12

    Novel liquid-like nanoparticle organic hybrid materials (NOHMs) made of polyetheramine chains tethered onto functionalized silica nanoparticles were synthesized and characterized before and after exposure to CO 2 using NMR, Raman, and ATR FT-IR spectroscopies in order to investigate the effect of the grafting densities on the NOHM canopy structure. Considering the promising tunable properties for CO 2 capture of NOHMs, this study was conducted to provide important structural information to better design NOHMs for CO 2 capture. In order to minimize the CO 2 absorption via enthalpic effect and provide a more accurate assessment of the structural effects, the NOHMs were synthesized without task-specific groups. A greater chain ordering and decreased intermolecular interactions were observed in NOHMs compared to the unbound polymer. This was attributed to the specific structural arrangement of the frustrated canopy. The distinct configuration of grafted polymer chains caused different CO 2 packing and CO 2-induced swelling behaviors between the NOHMs and the unbound polymer. The grafting density influenced the ordering and coupling of the polymer chains and CO 2-induced swelling. Its effect on the CO 2 packing behavior was less pronounced. © 2011 American Chemical Society.

  18. Evaluation of computer-assisted mandibular reconstruction with vascularized iliac crest bone graft compared to conventional surgery: a randomized prospective clinical trial

    Science.gov (United States)

    2014-01-01

    Background Computer-assisted surgery plays an increasingly important role in mandibular reconstruction, ensuring the best possible masticatory function and aesthetic outcome. Methods Twenty patients were randomly assigned to computer-assisted or conventional mandibular reconstruction with vascularized iliac crest bone graft in a prospective study design. Virtual surgical planning was based on preoperative CT-data using specific surgical planning software. A rapid prototyping guide transferred the virtual surgery plan to the operation site. During surgery the transplant ischemic time, reconstruction time, time for shaping the transplant and amount of bone removed were measured. Additionally, the difference in the intercondylar distance before and after surgery was calculated. Results Computer-assisted surgery shortened the time of transplant ischemia (P < 0.005) and defect reconstruction (P < 0.001) compared to conventional surgery. The time to saw and shape the transplant at the donor site was shorter using conventional surgery (P < 0.005); therefore, the overall time for surgery didn’t change (P = 0.527). In the computer-assisted group, the amount of bone harvested equaled the defect size, whereas the transplant size in the conventional group exceeded the defect site by 16.8 ± 5.6 mm (P < 0.001) on average. The intercondylar distance before compared to after surgery was less affected in the computer-assisted than in the conventional group (P < 0.001). Conclusions The presented study shows that computer-assisted surgery can help reduce the time for mandibular defect reconstruction and consequently the transplant ischemic time. In the computer-assisted group, the iliac crest donor site defect was downsized and the postoperative condyle position was less altered, reducing possible risks of postoperative complications and donor site morbidity. Trial Registration DRKS00005181. PMID:24716651

  19. The role of angiogenesis in implant dentistry part II: The effect of bone-grafting and barrier membrane materials on angiogenesis

    Science.gov (United States)

    Asatourian, Armen; Garcia-Godoy, Franklin; Sheibani, Nader

    2016-01-01

    Background In implant dentistry, bone substitute materials and barrier membranes are used in different treatments including guided bone regeneration (GBR), socket preservation, alveolar ridge augmentation, maxillary sinus elevation, and filling bony defects around the inserted dental implant. One of the most important factors in prognosis of treatments using these materials is the growth of new blood vessels in applied areas. Present review was performed to evaluate the effect of the bone-grafting and barrier membrane materials on angiogenesis events. Material and Methods An electronic search was performed in PubMed, MEDLINE, and EMBASE databases via OVID using the keywords mentioned in the PubMed and MeSH headings regarding the role of angiogenesis in implant dentistry from January 2000-April 2014. Results Of the 5,622 articles identified in our initial search results, only 33 met the inclusion criteria set for this review. Among bone substitute materials the autogenous bone-grafts, and among the barrier membranes the collagenous membranes, had the highest angiogenic potentials. Other bone-grafting materials or membranes were mostly used with pro-angiogenic factors to enhance their angiogenic properties. Conclusions Angiogenesis is one of the key factors, which plays a critical role in success rate of GBR technique and is seriously considered in manufacturing bone-grafting and barrier membrane materials. However, there is still lack of clinical and in-vivo studies addressing the effect of angiogenesis in treatments using bone-grafting and barrier membrane materials. Key words:Angiogenesis, bone-grafting materials, GBR, ridge augmentation, sinus elevation, socket preservation. PMID:27031074

  20. Tooth movement out of the bony wall using augmented corticotomy with nonautogenous graft materials for bone regeneration.

    Science.gov (United States)

    Lee, Kye-Bok; Lee, Dong-Yeol; Ahn, Hyo-Won; Kim, Seong-Hun; Kim, Eun-Cheol; Roitman, Igor

    2014-01-01

    This prospective randomized split-mouth study was performed to compare the effects of augmented corticotomy with those of different nonautogenous bone graft materials combined with orthodontic tooth movement in dogs. Decortication was performed on the buccal bone surface of 6 male beagle dogs that were randomly assigned to receive grafts of deproteinized bovine bone mineral, irradiated cortical bone, or synthetic bone. Immediate orthodontic force was applied to the second and third premolars for buccal tipping for 6 weeks. The pocket depth and width of keratinized tissue (WKT) were measured. Histologic and histomorphometric analyses were performed. The probing depth, WKT, and ratio of the area of new bone to that of total bone on the buccal side were not significantly different between groups. All groups had considerable new bone formation on the pressure side. New bone formation on the buccal side and buccal plate formation in the coronal direction along the root surfaces were induced by the bone-derived and PDL-derived mesenchymal matrix, respectively. The angular change between groups was significantly different (P materials facilitated tooth movement without fenestrations and accelerated new bone formation on the pressure side.

  1. Systemic and local antibiotic prophylaxis in the prevention of Staphylococcus epidermidis graft infection

    Directory of Open Access Journals (Sweden)

    Asan Ali

    2005-10-01

    Full Text Available Abstract Background The aim of the study was to investigate the in vivo efficacy of local and systemic antibiotic prophylaxis in the prevention of Staphylococcus (S. epidermidis graft infection in a rat model and to evaluate the bacterial adherence to frequently used prosthetic graft materials. Methods Graft infections were established in the subcutaneous tissue of 120 male Wistar rats by implantation of Dacron/ePTFE grafts followed by topical inoculation with 2 × 107 CFUs of clinical isolate of methicillin-resistant S. epidermidis. Each of the graft series included a control group, one contaminated group that did not receive any antibiotic prophylaxis, two contaminated groups that received systemic prophylaxis with teicoplanin or levofloxacin and two contaminated groups that received teicoplanin-soaked or levofloxacin-soaked grafts. The grafts were removed 7 days after implantation and evaluated by quantitative culture. Results There was significant bacterial growth inhibition in the groups given systemic or local prophylaxis (P S. epidermidis had greater affinity to Dacron graft when compared with ePTFE graft in the untreated contaminated groups (P Conclusion The study demonstrated that the usage of systemic or local prophylaxis and preference of ePTFE graft can be useful in reducing the risk of vascular graft infections caused by staphylococcal strains with high levels of resistance.

  2. Alveolar ridge preservation after tooth extraction: a Bayesian Network meta-analysis of grafting materials efficacy on prevention of bone height and width reduction.

    Science.gov (United States)

    Iocca, Oreste; Farcomeni, Alessio; Pardiñas Lopez, Simon; Talib, Huzefa S

    2017-01-01

    To conduct a traditional meta-analysis and a Bayesian Network meta-analysis to synthesize the information coming from randomized controlled trials on different socket grafting materials and combine the resulting indirect evidence in order to make inferences on treatments that have not been compared directly. RCTs were identified for inclusion in the systematic review and subsequent statistical analysis. Bone height and width remodelling were selected as the chosen summary measures for comparison. First, a series of pairwise meta-analyses were performed and overall mean difference (MD) in mm with 95% CI was calculated between grafted versus non-grafted sockets. Then, a Bayesian Network meta-analysis was performed to draw indirect conclusions on which grafting materials can be considered most likely the best compared to the others. From the six included studies, seven comparisons were obtained. Traditional meta-analysis showed statistically significant results in favour of grafting the socket compared to no-graft both for height (MD 1.02, 95% CI 0.44-1.59, p value Bayesian Network meta-analysis allowed to obtain a rank of intervention efficacy. On the basis of the results of the present analysis, socket grafting seems to be more favourable than unassisted socket healing. Moreover, Bayesian Network meta-analysis indicates that freeze-dried bone graft plus membrane is the most likely effective in the reduction of bone height remodelling. Autologous bone marrow resulted the most likely effective when width remodelling was considered. Studies with larger samples and less risk of bias should be conducted in the future in order to further strengthen the results of this analysis. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Plasma protein corona modulates the vascular wall interaction of drug carriers in a material and donor specific manner.

    Directory of Open Access Journals (Sweden)

    Daniel J Sobczynski

    Full Text Available The nanoscale plasma protein interaction with intravenously injected particulate carrier systems is known to modulate their organ distribution and clearance from the bloodstream. However, the role of this plasma protein interaction in prescribing the adhesion of carriers to the vascular wall remains relatively unknown. Here, we show that the adhesion of vascular-targeted poly(lactide-co-glycolic-acid (PLGA spheres to endothelial cells is significantly inhibited in human blood flow, with up to 90% reduction in adhesion observed relative to adhesion in simple buffer flow, depending on the particle size and the magnitude and pattern of blood flow. This reduced PLGA adhesion in blood flow is linked to the adsorption of certain high molecular weight plasma proteins on PLGA and is donor specific, where large reductions in particle adhesion in blood flow (>80% relative to buffer is seen with ∼60% of unique donor bloods while others exhibit moderate to no reductions. The depletion of high molecular weight immunoglobulins from plasma is shown to successfully restore PLGA vascular wall adhesion. The observed plasma protein effect on PLGA is likely due to material characteristics since the effect is not replicated with polystyrene or silica spheres. These particles effectively adhere to the endothelium at a higher level in blood over buffer flow. Overall, understanding how distinct plasma proteins modulate the vascular wall interaction of vascular-targeted carriers of different material characteristics would allow for the design of highly functional delivery vehicles for the treatment of many serious human diseases.

  4. [Vascular trauma].

    Science.gov (United States)

    Furuya, T; Nobori, M; Tanaka, N

    1999-07-01

    Vascular trauma is essentially acute arterial obstruction, often combined with hemorrhage, fracture, and infection. It can be both life-threatening and limb-threatening and needs an emergency operation. In vascular trauma patient, multiple fracture and organ injury, such as brain, lung, liver, spleen, kidney, or gastrointestinal tract should be evaluated to decide treatment priority. When the pulse distal from the injured site is absent or diminished, vascular trauma is most likely and reconstruction should be accomplished within "the golden time (6-8 hours)". Intimal damage followed by platelet aggregation and thrombus formation will necessitate resection and repair of the site instead of simple thrombectomy. Although autogenous vein is the first choice, artificial graft can be implanted for short segment in non-infected field.

  5. Durable and Washable Antibacterial Copper Nanoparticles Bridged by Surface Grafting Polymer Brushes on Cotton and Polymeric Materials

    Directory of Open Access Journals (Sweden)

    Chufeng Sun

    2018-01-01

    Full Text Available To increase the durability of antibacterial coating on cotton and polymeric substrates, surface initiated grafting polymer brushes are introduced onto the substrates surface to bridge copper nanoparticles coatings and substrate. The morphologies of the composites consisting of the copper nanoparticles and polymer brushes were characterized with scanning electron microscopy (SEM. It was found that copper nanoparticles were uniformly and firmly distributed on the surfaces of the substrates by the polymer brushes; meanwhile, the reinforced concrete-like structures were formed in the composite materials. The substrates coated by the copper nanoparticles showed the efficient antibacterial activity against Staphylococcus aureus (S. aureus and Escherichia coli (E. coli even after washing by 30 cycles. The copper nanoparticles were tethered on the substrates by the strong chemical bonds, which led to the excellent washable fitness and durability. The change of the phase structure of the copper was analyzed to investigate the release mechanism of copper ions.

  6. Surface modification of polyisobutylene via grafting amino acid-based poly (acryloyl-6-aminocaproic acid) as multifunctional material.

    Science.gov (United States)

    Du, Yanqiu; Li, Chunming; Jin, Jing; Li, Chao; Jiang, Wei

    2018-01-01

    Amino acid-based P(acryloyl-6-aminocaproic acid) (PAACA) brushes were fabricated on polyisobutylene (PIB) surface combined with plasma pre-treatment and UV-induced grafting polymerization to construct an antifouling and functional material. The hydrophilicity and hemocompatibility of PIB were largely improved by surface modification of AACA, which were confirmed by water contact angle and platelet adhesion, respectively. PAACA brushes were precisely located onto the surface of PIB to create a patterned PIB-g-PAACA structure, and then the carboxyl groups on PAACA was activated to immobilize functional protein-Concanavalin A (Con A). The obtained Con A-coupled microdomains could further capture erythrocytes. This method developed a platform on commercial PIB surface via amino acid-based polymer brushes which had a promising application in drug delivery and disease diagnosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Graft infections after surgical aortic reconstructions

    NARCIS (Netherlands)

    Berger, P.

    2015-01-01

    Prosthetic vascular grafts are frequently used to reconstruct (part) of the aorta. Every surgical procedure caries a certain risk for infection and when a prosthetic aortic graft is implanted, this may lead to an aortic graft infection (AGI). Endovascular techniques have gradually replaced open

  8. Extracellular Matrix Molecules Facilitating Vascular Biointegration

    Directory of Open Access Journals (Sweden)

    Martin K.C. Ng

    2012-08-01

    Full Text Available All vascular implants, including stents, heart valves and graft materials exhibit suboptimal biocompatibility that significantly reduces their clinical efficacy. A range of biomolecules in the subendothelial space have been shown to play critical roles in local regulation of thrombosis, endothelial growth and smooth muscle cell proliferation, making these attractive candidates for modulation of vascular device biointegration. However, classically used biomaterial coatings, such as fibronectin and laminin, modulate only one of these components; enhancing endothelial cell attachment, but also activating platelets and triggering thrombosis. This review examines a subset of extracellular matrix molecules that have demonstrated multi-faceted vascular compatibility and accordingly are promising candidates to improve the biointegration of vascular biomaterials.

  9. Anatomic changes due to interspecific grafting in cassava (Manihot esculenta).

    Science.gov (United States)

    Bomfim, N; Ribeiro, D G; Nassar, N M A

    2011-05-31

    Cassava rootstocks of varieties UnB 201 and UnB 122 grafted with scions of Manihot fortalezensis were prepared for anatomic study. The roots were cut, stained with safranin and alcian blue, and examined microscopically, comparing them with sections taken from ungrafted roots. There was a significant decrease in number of pericyclic fibers, vascular vessels and tyloses in rootstocks. They exhibited significant larger vessels. These changes in anatomic structure are a consequence of genetic effects caused by transference of genetic material from scion to rootstock. The same ungrafted species was compared. This is the first report on anatomic changes due to grafting in cassava.

  10. Bone augmentation procedures in localized defects in the alveolar ridge: clinical results with different bone grafts and bone-substitute materials

    DEFF Research Database (Denmark)

    Jensen, Simon Storgård; Terheyden, Hendrik

    2009-01-01

    PURPOSE: The objective of this review was to evaluate the efficacy of different grafting protocols for the augmentation of localized alveolar ridge defects. MATERIALS AND METHODS: A MEDLINE search and an additional hand search of selected journals were performed to identify all levels of clinical...

  11. Complexes of Silver(I Ions and Silver Phosphate Nanoparticles with Hyaluronic Acid and/or Chitosan as Promising Antimicrobial Agents for Vascular Grafts

    Directory of Open Access Journals (Sweden)

    Vojtech Adam

    2013-06-01

    Full Text Available Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other

  12. Biologically engineered protein-graft-poly(ethylene glycol) hydrogels: A cell-adhesive and plasmin-degradable biosynthetic material for tissue repair

    Science.gov (United States)

    Halstenberg, Sven

    2002-01-01

    The goal of the research presented in this dissertation was to create a biomimetic artificial material that exhibits functions of extracellular matrix relevant for improved nerve regeneration. Neural adhesion peptides were photoimmobilized on highly crosslinked poly(ethylene glycol)-based substrates that were otherwise non-adhesive. Neurons adhered in two-dimensional patterns for eleven hours, but no neurites extended. To enable neurite extension and nerve regeneration in three dimensions, and to address the need for specifically cell adhesive and cell degradable materials for clinical applications in tissue repair in general, an artificial protein was recombinantly expressed and purified that consisted of a repeating amino acid sequence based on fibrinogen and anti-thrombin III. The recombinant protein contained integrin-binding RGD sites, plasmin degradation sites, heparin binding sites, and six thiol-containing cysteine residues as grafting sites for poly(ethylene glycol) diacrylate via Michael-type conjugate addition. The resulting protein-graft-poly(ethylene glycol)acrylates were crosslinked by photopolymerization to form hydrogels. Although three-dimensional, RGD mediated and serine protease-dependent ingrowth of human fibroblasts into protein-graft-poly(ethylene glycol) hydrogels occurred, only surface neurite outgrowth was observed from chick dorsal root ganglia. Axonal outgrowth depended on the concentration of matrix-bound heparin, suggesting that improved mechanical strength of the hydrogels and possible immobilization of neuroactive factors due to the presence of heparin promoted neurite outgrowth. Together, the above results show that specific biological functions can be harnessed by protein-graft-poly(ethylene glycol) hydrogels to serve as matrices for tissue repair and regeneration. In particular, the two design objectives, specific cell adhesion and degradability by cell-associated proteases, were fulfilled by the material. In the future, this and

  13. Randomized trial of graft materials in transobturator tape operation: biological versus synthetic.

    Science.gov (United States)

    Ugurlucan, Funda Gungor; Erkan, Habibe Ayyildiz; Onal, Murat; Yalcin, Onay

    2013-08-01

    To compare the outcome of outside-in biological and synthetic transobturator tape (TOT) operation, including subjective and objective success rates, urodynamics, and quality of life. One hundred patients suffering from clinical and/or urodynamic stress urinary incontinence (SUI) were randomized into biological material TOT (PELVILACE® TO) or synthetic material TOT (ALIGN®TO Urethral Support System) groups. Preoperative and at 1 year postoperative urogynecological symptom assessment, 1-h pad test, 4-day bladder diary, stress test, Q-tip test, and urodynamics were performed. For the evaluation of quality of life, the King's Health Questionnaire, Urogenital Distress Inventory-6, Incontinence Impact Questionnaire-7, and Prolapse Quality of Life were used. There was no significant difference between the two groups regarding objective and subjective cure rates and quality of life. At 1-year follow-up, the subjective cure rate was 68 % in the biological material TOT and 70 % in the synthetic material TOT group. No perioperative complications developed. Groin pain developed in 2 patients in the biological TOT group and 1 patient had dehiscence in the periurethral incision, which healed with local estrogen. Two patients had transient urinary retention in the synthetic TOT group, 1 patient developed groin pain, and 1 patient had mesh erosion observed at the 1-year follow-up. Transobturator tape with biological material in the management of SUI has a rate of success and patient satisfaction similar to those of synthetic material at 1-year follow-up. Studies with longer follow-up and larger cohorts are necessary to evaluate possible autolysis and degradation of biological slings and a possible reduction in efficacy over time.

  14. Non-Immunogenic Structurally and Biologically Intact Tissue Matrix Grafts for the Immediate Repair of Ballistic-Induced Vascular and Nerve Tissue Injury in Combat Casualty Care

    Science.gov (United States)

    2005-07-01

    to be associated with lumenal defects in one of the grafts. The current anti-platelet therapy regime, consisting of daily aspirin and Plavix and...days after surgery. No antiplatelet or anticoagulant agents were given during or following surgery. B. Implantability Nine UVG segments from three

  15. Repair of bone defects with prefabricated vascularized bone grafts and double-labeled bone marrow-derived mesenchymal stem cells in a rat model

    National Research Council Canada - National Science Library

    Jiang, Xiao-Rui; Yang, Hui-Ying; Zhang, Xin-Xin; Lin, Guo-Dong; Meng, Yong-Chun; Zhang, Pei-Xun; Jiang, Shan; Zhang, Chun-Lei; Huang, Fei; Xu, Lin

    2017-01-01

    ...) and osteoblasts (OBs). Rats were divided into five groups: Group A: in vitro prefabrication with EPCs-RFP + in vivo prefabrication with arteriovenous vascular bundle + secondary OBs-GFP implantation; Grou...

  16. Graft Infection Masquerading as Rheumatologic Disease: a Rare Case of Aortobifemoral Graft Infection Presenting as Hypertrophic Osteoarthropathy.

    Science.gov (United States)

    Chapman, Stephanie A; Delgadillo, Daniel; MacGuidwin, Elizabeth; Greenberg, Joshua I; Jameson, Andrew P

    2017-05-01

    Prosthetic vascular graft procedures are a common treatment modality for peripheral vascular disease. A relatively common complication is graft infection, occurring at a rate of 0.5-5%. When they occur, graft infections are associated with significant morbidity and mortality. Vascular graft infections also represent a diagnostic and therapeutic challenge for the physician METHODS: Here, we report a case where the rare finding of secondary hypertrophic osteoarthropathy was an important indication of underlying aortic graft infection that was initially misdiagnosed. A review of the literature revealed 34 cases of vascular graft infection associated with hypertrophic osteoarthropathy. The mean interval from surgery to time of infection was approximately 5 years. Mortality was 35%. When combined with hypertrophic osteoarthropathy, vascular graft infection was complicated by an aortoenteric fistula in 53% of the cases. The complexity of this case highlights the challenges physicians face in order to diagnose and treat this condition. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Feasibility of Human Skin Grafts on An Isolated But Accessible Vascular Supply on Athymic Rats As a System to Study Percutaneous Penetration and Cutaneous Injury

    Science.gov (United States)

    1986-06-01

    Bordetella pertussis toxin: Bordeteila pertussis toxin (BPT) is known to prolong grafts across major histocompatibility (MHC) barriers (28). Rats...that indicate an absence of cell-mediated immune responses in nude rats (10,34,35), the present observations suggest that an immunologic mechanism is... immunologic properties (30). The cytotoxic response of lymphocytes of draining lymph nodes of the rats which have rejected HSTSG to human peripheral

  18. The defective protein level of myosin light chain phosphatase (MLCP) in the isolated saphenous vein, as a vascular conduit in coronary artery bypass grafting (CABG), harvested from patients with diabetes mellitus (DM).

    Science.gov (United States)

    Matsuo, Yasuko; Kuwabara, Masachika; Tanaka-Totoribe, Naoko; Kanai, Tasuku; Nakamura, Eisaku; Gamoh, Shuji; Suzuki, Akito; Asada, Yujiro; Hisa, Hiroaki; Yamamoto, Ryuichi

    2011-08-26

    We examined the contractile reactivity to 5-hydroxytryptamine (5-HT) in isolated human saphenous vein (SV), as a vascular conduit in coronary artery bypass grafting (CABG), harvested from patients with diabetes mellitus (DM) and non-DM (NDM). Vascular rings of endothelium-denuded SV were used for functional and biochemical experiments. The vasoconstrictions caused by 5-HT were significantly greater (hyperreactivity) in the DM group than in the NDM group. RhoA/ROCK pathway is activated by various G-protein-coupled receptor agonists and consequently induces phosphorylation of myosin phosphatase target subunit 1 (MYPT1), a subunit of myosin light chain phosphatase (MLCP), which inhibits MLCP activity. In the resting state of the vessels, total tissue protein levels of 5-HT(2A) receptor, 5-HT(1B) receptor, RhoA, ROCK1, and ROCK2 did not differ between NDM and DM groups. However, the total protein level of MYPT1 was significantly lower in the DM group than in the NDM group. Furthermore, the ratio of P(Thr(696))-MYPT1 to total MYPT1 was significantly higher in the DM group than in the NDM group. These results suggest that the hyperreactivity to 5-HT in the SV smooth muscle of patients with DM is due to not only enhanced phosphorylation of MLCP but also defective protein level of MLCP. Thus, we reveal for the first time that the defective protein level of MLCP in the DM group can partially explain the poor patency of SV graft harvested from patients with DM. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Ipsilateral Femoral Fracture Non-Union and Delayed Union Treated By Hybrid Plate Nail Fixation and Vascularized Fibula Bone Grafting: A Case Report

    Directory of Open Access Journals (Sweden)

    CK Chan

    2013-07-01

    Full Text Available Non-union is a well recognized complication of femoral neck fractures. The decision whether to attempt fracture fixation or to resort to hip replacement is particularly difficult in patients in the borderline age group in whom complex attempts at gaining union may fail and later present a difficult revision. On the other hand the patient may be young enough that arthroplasty best be avoided . Besides, presence of ipsilateral femoral shaft fracture with delayed union in addition to the femoral neck non-union will pose major problems at operation. We share our experience in treating a femoral neck fracture non-union with ipsilateral femoral shaft delayed union in the shaft and in the distal femur in a fifty years old patient. The fracture was treated with an angle blade plate and supracondylar nail supplemented with a free vascularised fibular bone grafting and autologous cancellous graft. There was radiological union at fourth month. At sixth months, the patient was free of pain and able to walk without support. Thus, we would like to suggest that vascularised fibula bone grafting with supracondylar nailing is a viable option for this pattern of fracture.

  20. Emergency autologous vein graft reconstruction after using a vascular closure device Reconstrução de emergência de enxerto autólogo de veia após uso de dispositivo de fechamento vascular

    Directory of Open Access Journals (Sweden)

    Giel G Koning

    2011-06-01

    Full Text Available An emergency operation for access related acute critical limb ischemia with signs of infection is described. Inguinal femoral reconstruction was performed with a bifurcated graft constructed from the ipsilateral saphenous vein.Uma operação de emergência relacionada à isquemia aguda com sinais de infecção é descrita. Reconstrução femoral inguinal foi realizada com um enxerto bifurcado feito a partir da veia safena ipsilateral.

  1. Mucous membrane grafting.

    Science.gov (United States)

    Henderson, H W A; Collin, J R O

    2008-01-01

    We review the use of mucous membrane grafting in the clinical management of dry eye-associated ocular surface disease. Literature review of the scientific evidence, presentation of guidelines and surgical details. The reformation and maintenance of a conjunctival fornix requires the addition of epithelial tissue, or a basement membrane which can be populated by healthy host epithelial cells. A healthy conjunctival or tarsal autograft, when available, is the ideal material. Oral mucosa does not contain goblet cells and therefore does not supplement the tear film: a full-thickness oral mucous membrane graft is the simplest graft to use if conjunctiva or tarsus is not available. Split-thickness mucosal grafts contract more, but are less bulky and pink than full-thickness grafts, and therefore should be used on the globe. Hard palate grafts are the thickest oral mucosal grafts and contract the least. Nasal mucosal grafts contain goblet cells that may contribute mucous to the tear film. This is maximised in turbinate mucosal grafts, which can relieve discomfort in extreme dry eye situations. Nasal septal cartilage contains fewer goblet cells, but adds rigidity. Amniotic membrane is thin and translucent-like conjunctiva, and possesses antiangiogenic, antiscarring and anti-inflammatory properties. It may become re-epithelialised with normal a conjunctival cell population and prevent postoperative cicatrisation, but requires the presence of healthy conjunctival stem cells to repopulate the graft, adequate lacrimal function to keep the graft moist, and a host site that is free from inflammation, otherwise it rapidly contracts. It can be combined with limbal transplantation and with an adjunctive antimetabolite.

  2. Bioengineering of cultured epidermis from adult epidermal stem cells using Mebio gel sutable as autologous graft material

    Directory of Open Access Journals (Sweden)

    Lakshmana K Yerneni

    2007-01-01

    Full Text Available Closure of burn wound is the primary requirement in order to reduce morbidity and mortality that are otherwise very high due to non-availability of permanent wound covering materials. Sheets of cultured epidermis grown from autologous epidermal keratinocyte stem cells are accepted world over as one of the best wound covering materials. In a largely populated country like ours where burn casualties occur more frequently due to inadequate safety practices, there is a need for indigenous research inputs to develop such methodologies. The technique to culturing epidermal sheets in vitro involves the basic Reheinwald-Green method with our own beneficial inputs. The technique employs attenuated 3T3 cells as feeders for propagating keratinocyte stem cells that are isolated from the epidermis of an initial skin biopsy of about 5 cm2 from the patient. The cultures are then maintained in Dulbecco's modified Eagle's medium strengthened with Ham's F12 formula, bovine fetal serum and various specific growth-promoting agents and factors in culture flasks under standard culture conditions. The primary cultures thus established would be serially passaged to achieve the required expansion. Our major inputs are into the establishment of (1 an efficient differential trypsinization protocol to isolate large number epidermal keratinocytes from the skin biopsy, (2 a highly specific, unique and foolproof attenuation protocol for 3T3 cells and (3 a specialized and significant decontamination protocol. The fully formed epidermal sheet as verified by immuno-histochemical and light & electron microscopic studies, is lifted on to paraffin gauze by incubating in a neutral protease. The graft is then ready to be transported to the operating theatre for autologous application. We have a capability of growing cultured epidermal sheets sufficient enough to cover 40 per cent burn wound in 28 days. The preliminary small area clinical applications undertaken so far revealed

  3. The Use of Light/Chemically Hardened Polymethylmethacrylate, Polyhydroxyethylmethacrylate, and Calcium Hydroxide Graft Material in Combination With Polyanhydride Around Implants in Minipigs: Part I: Immediate Stability and Function

    Science.gov (United States)

    Hasturk, Hatice; Kantarci, Alpdogan; Ghattas, Mazen; Schmidt, Marcella; Giordano, Russell A.; Ashman, Arthur; Diekwisch, Thomas G.; Van Dyke, Thomas

    2015-01-01

    Background The present study is designed as a proof-of-concept study to evaluate light/chemical hardening technology and a newly formulated polymethylmethacrylate, polyhydroxyethylmethacrylate, and calcium hydroxide (PPCH) plus polyanhydride (PA) (PPCH-PA) composite graft material as a bone substitute compared to positive and negative controls in a minipig model. Methods PPCH-PA (composite graft); PPCH alone (positive control), PA alone (positive control), and no graft (negative control) were compared. Four mandibular premolar teeth per quadrant were extracted; a total of 48 implants were placed into sockets in three minipigs. Abutments were placed protruding into the oral cavity 4 mm in height for immediate loading. Crestal areas and intrabony spaces were filled with PPCH-PA, PPCH, or PA using a three-phase delivery system in which all graft materials were hardened by a light cure. In the negative control group, implant sites were left untreated. At 12 weeks, block sections containing implants were obtained. Evaluations included periodontal probing, pullout-force load, and stability measurements to determine implant stability, radiographs to examine bone levels, and scanning electron microscopy (SEM)–energy-dispersed spectroscopy to determine bone-to-implant contact. Results Probing measurements did not reveal any pathologic pocket formation or bone loss. Radiographs revealed that immediate implant placement and loading resulted in bone at or slightly apical to the first thread of the implant in all groups at 12 weeks. Stability test values showed a relative clinical stability for all implants (range: −7 to +1); however, implants augmented with PPCH-PA exhibited a statistically significantly greater stability compared to all other groups (P implant–socket interface in the PPCH-PA group compared to other groups with reduced microfissures and implant–bone interface fractures during pullout testing, whereas implants treated with PA or no graft showed ≈10-

  4. Cysteine-grafted nonwoven geotextile: a new and efficient material for heavy metals sorption--Part B.

    Science.gov (United States)

    Vandenbossche, M; Vezin, H; Touati, N; Jimenez, M; Casetta, M; Traisnel, M

    2014-10-01

    The development of a new material designed to trap heavy metals from sediments or wastewater, based on a polypropylene non-woven covalently grafted with cysteine, has been reported in a previous paper (Part A). The non-woven was first functionalized with acrylic acid (AA) which is used as spacer, and then cysteine was immobilized on the substrate through covalent coupling in order to obtain the so-called PP-g-AA-cysteine. Some preliminary heavy metals adsorption tests gave interesting results: at 20 °C for 24 h and in a 1000 mg/L heavy metals solution, PP-g-AA-cysteine adsorbs 95 mg Cu/g PP (CuSO4 solution), 104 mg Cu/g PP (Cu(NO3)2 solution), 135 mg Pb/g PP (Pb(NO3)2 solution) and 21 mg Cr/g PP (Cr(NO3)3 solution). In this second part of the work, heavy metals sorption tests were carried out with Cu (II), Pb (II), and Cr (III) separately, in order to determine the sorption capacity of this new sorbent as a function of (i) the heavy metals concentration in the solution, (ii) the contact time with the solution, (iii) the pH and (iv) the ionic strength of the solution containing heavy metals. Moreover, the sorption capacity of PP-g-AA-Cysteine was studied using a polluted solution consisting of a mixture of these different heavy metals. An Electron Paramagnetic Resonance study was finally carried out in order to determine the coordination geometry in the environment of the copper trapped by the PP-g-AA-cysteine. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Effect of a tunnel-structured β-tricalcium phosphate graft material on periodontal regeneration: a pilot study in a canine one-wall intrabony defect model.

    Science.gov (United States)

    Matsuura, T; Akizuki, T; Hoshi, S; Ikawa, T; Kinoshita, A; Sunaga, M; Oda, S; Kuboki, Y; Izumi, Y

    2015-06-01

    Tissue regeneration is affected by the porosity, chemical properties and geometric structure of graft materials. Regeneration of severe periodontal defects, such as one-wall intrabony defects, is difficult because of reduced tissue support, and bone grafts are commonly used in such cases. In the present study, a tunnel-structured β-tricalcium phosphate (tunnel β-TCP) graft material designed to stimulate bone formation was fabricated. The objective of this pilot study was to evaluate the effect of this graft material on periodontal regeneration in one-wall intrabony defects in dogs. Six male beagle dogs were used in this study. First, the mandibular second and third incisors were extracted. Experimental surgery was performed 12 wk after tooth extraction. Bilateral 4 × 8 mm (width × depth) one-wall intrabony defects were created in the mesial side of the mandibular canines. At the experimental sites, the defects were filled with tunnel β-TCP, whereas the control defects were left empty. Twelve weeks after surgery, qualitative and quantitative histological analyses were performed. There were no signs of clinical inflammation 12 wk after surgery. Coronal extension indicative of new bone formation was higher at the experimental sites than at the control sites, although the differences between both the sites in the newly formed cementum and connective tissue attachment were not significant. Newly formed periodontal ligament and cementum-like tissue were evident along the root surface at the experimental sites. The inner surface of the tunnels was partially resorbed and replaced with new bone. New blood vessels were observed inside the lumens of tunnel β-TCP. Tunnel β-TCP serves as a scaffold for new bone formation in one-wall intrabony defects. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Synthesis of SnO2 pillared carbon using long chain alkylamine grafted graphene oxide: an efficient anode material for lithium ion batteries.

    Science.gov (United States)

    Reddy, M Jeevan Kumar; Ryu, Sung Hun; Shanmugharaj, A M

    2016-01-07

    With the objective of developing new advanced composite materials that can be used as anodes for lithium ion batteries (LIBs), herein we describe the synthesis of SnO2 pillared carbon using various alkylamine (hexylamine; dodecylamine and octadecylamine) grafted graphene oxides and butyl trichlorotin precursors followed by its calcination at 500 °C for 2 h. While the grafted alkylamine induces crystalline growth of SnO2 pillars, thermal annealing of alkylamine grafted graphene oxide results in the formation of amorphous carbon coated graphene. Field emission scanning electron microscopy (FE-SEM) results reveal the successful formation of SnO2 pillared carbon on the graphene surface. X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy characterization corroborates the formation of rutile SnO2 crystals on the graphene surface. A significant rise in the BET surface area is observed for SnO2 pillared carbon, when compared to pristine GO. Electrochemical characterization studies of SnO2 pillared carbon based anode materials showed an enhanced lithium storage capacity and fine cyclic performance in comparison with pristine GO. The initial specific capacities of SnO2 pillared carbon are observed to be 1379 mA h g(-1), 1255 mA h g(-1) and 1360 mA h g(-1) that decrease to 750 mA h g(-1), 643 mA h g(-1) and 560 mA h g(-1) depending upon the chain length of grafted alkylamine on the graphene surface respectively. Electrochemical impedance spectral analysis reveals that the exchange current density of SnO2 pillared carbon based electrodes is higher, corroborating its enhanced electrochemical activity in comparison with GO based electrodes.

  7. Evaluation of HTR polymer (Bioplant® HTR® as a bone graft material in the treatment of interproximal vertical bony defects: A clinical and radiological study

    Directory of Open Access Journals (Sweden)

    Prakash Shobha

    2010-01-01

    Full Text Available Background and Objectives : Bone grafting is the most common form of regenerative therapy. Several bone substitutes have been used in clinical periodontal therapy to encourage bone formation. The present study has been undertaken to evaluate the efficacy of hard tissue replacement polymer (Bioplant® HTR® as a bone graft material in the treatment of interproximal vertical bony defects in human beings, both clinically and radiologically. Materials and Methods : Five chronic periodontitis patients were selected with 16 sites assigned randomly into control (open debridement alone and experimental (open flap debridement plus Bioplant® HTR® groups. Clinical measurements like plaque index (PI, gingival index (GI, probing pocket depth (PPD, clinical attachment level (CAL, gingival margin position (GMP assessment was done at 0, 3 and 6 months and radiographic assessment at 0 and 6 month. Statistical analysis was performed using Wilcoxon′s signed Rank test and Mann-whitney U-test. Results : There were statistically no significant (P=1.00 changes in Plaque index and Gingival Index scores in both the groups from baseline to six months post surgery. Statistically significant (P< 0.05 reduction in Probing Pocket Depth was seen on comparison between the groups. In relation to the hard tissue changes, significant results were seen with respect to change in alveolar crest and percentage of original defect resolved. Comparison of results from six to 12 months following similar treatments showed no significant differences or advantages to having a clinical evaluation period longer than 6 months post surgically (Yukna 1999. Interpretation and Conclusion : Bioplant® HTR® material is a biocompatible, easy to handle and a beneficial grafting material for the treatment of periodontal osseous defects.

  8. Apical and marginal bone alterations around implants in maxillary sinus augmentation grafted with autogenous bone or bovine bone material and simultaneous or delayed dental implant positioning.

    Science.gov (United States)

    Sbordone, Ludovico; Levin, Liran; Guidetti, Franco; Sbordone, Carolina; Glikman, Ari; Schwartz-Arad, Devorah

    2011-05-01

    A re-pneumatization phenomenon was recorded in sinuses grafted with different materials. The specific aims of this paper were to assess the dental implant survival rate and the behavior of marginal and apical bone remodeling around dental implants placed following sinus augmentation. A retrospective study was conducted on consecutive patients treated in two surgical centers. Different surgical techniques were adopted for sinus augmentation: simultaneous or delayed dental implant insertion with bovine bone-material augmentation or autologous bone grafting (chin and iliac crest). Survival rates were recorded for the overall number of implants (patients of group A). Apical and marginal bone levels (ABL and MBL, respectively) were radiographically measured, and statistical analysis was performed in implants of a subgroup of patients (group B). A total of 282 dental implants were positioned. Recorded cumulative survival rates (CSRs) were 95.6% and 100% for autogenous and bovine bone material, respectively, while CSRs at 2-year follow-up for immediate and delayed procedures were 99.3% and 96.5%. For the subgroup B, 57 sinus augmentation procedures were performed in 39 patients, with the positioning of 154 implants. Generally, the apical- and marginal-bone resorption of the bovine bone-material group was less than that of the autogenous group. The differences between the ABL values of the bovine bone-material and iliac-crest groups were statistically significant at 1 year, whereas this significance disappeared at the 2-year follow-up; tests showed that a statistical difference was recorded in the bovine bone-material group between the 1- and 2-year follow-ups. With regard to MBL comparisons between simultaneous and delayed implantation, the differences maintained their significance at the 2-year follow-up also. Differences regarding apical bone alteration between autogenous bone from the iliac crest and bovine bone material at the 1- and 2-year follow-ups, as well as in

  9. Use of T.M.J. Disc as a Soft Tissue Interpositional Graft Material for Functional Rehabilitation of Ankylosed T.M. Joint.

    Science.gov (United States)

    Bedi, Ravinder Singh; Khemka, Upasana; Singh, Jaipal; Yadav, Manoj; Singh, Pratibha

    2017-06-01

    Many surgical techniques have been described for the treatment of TMJ ankylosis, but no strategy has been uniformly agreed upon underscoring the difficulty of the problem. Despite new guidelines and updated methods, treating patients with TMJ Ankylosis remains a challenge as the incidence of recurrence after treatment is soaring. This study exemplifies our experience in using an unsullied method to treat TMJ Ankylosis to restore the structure of TMJ in conjunction with convalescing secondary maxillofacial deformity. A total of 56 cases of unilateral bony TMJ ankylosis were included in the study, and postoperative results of T.M.J disc as a soft tissue interposition graft was evaluated. The operative protocol comprised of (1) resection of ankylotic mass, (2) intraoral ipsilateral coronoidectomy or contralateral coronoidectomy when needed, (4) interpositioning disc as soft tissue graft, (5) interposing and fixing sternoclavicular or costocondral graft with lag screws and (6) early mobilization, aggressive physiotherapy. The study assessed patients with regular follow-up checks for a period of 3 years. The average preoperative mouth opening was found to be 5.46 mm (range 2-10 mm). Mean post-operative mouth opening was 33.05 mm (range 24-43 mm), while 3 years post operative mouth opening (mean) was 39.75 mm. No cases of reankylosis were reported during this period suggesting it as a viable and satisfactory approach. The use of TMJ disc as a soft tissue interpositional graft material is an effectual method for functional rehabilitation of ankylosis cases and serves as an effective means of preventing recurrence.

  10. A comparison between PTFE and denatured homologous vein grafts for haemodialysis access: a prospective randomised multicentre trial. The SMASH Study Group. Study of Graft Materials in Access for Haemodialysis.

    Science.gov (United States)

    Bosman, P J; Blankestijn, P J; van der Graaf, Y; Heintjes, R J; Koomans, H A; Eikelboom, B C

    1998-08-01

    To compare patency and complication rates of polytetrafluoroethylene (PTFE) grafts and denatured homologous vein (DHV) grafts for long-term haemodialysis. A prospective randomised multicentre trial. One hundred and thirty-one patients were enrolled between September 1994 and April 1997. Sixty-three DHV grafts and 68 PTFE grafts were implanted in 60 meals and 71 females. Complications and interventions were monitored. Patency rates, complication rates, and intervention rates of PTFE and DHV were compared. The mean follow-up was 313 days for DHV (range 1-771) and 339 (3-909) days for PTFE. The total follow-up was 54.1 patient-years for DHV and 63.1 for PTFE. The 1-year primary patency rates were 30% and 40% for DHV and PTFE respectively. Secondary patency rate was 63% for both DHV and PTFE. Most frequent complication was thrombosis. A total of 75 thrombotic events (1.39 per patient-year) occurred in 35 (56%) DHV grafts and 78 (1.24 per py) in 36 (53%) PTFE grafts. A total of nine infections were seen in nine (14%) DHV grafts, whereas 21 infections in 20 (29%) PTFE grafts were seen (p = 0.08). All but one infected DHV graft could be salvaged with systemic antibiotics. In contrast, surgical intervention was necessary in nine PTFE grafts (p = 0.02). For aneurysms, eight DHV and two PTFE grafts needed revision (p = 0.03). Patency rates between DHV and PTFE were not different. More infections were seen in PTFE grafts, and significantly more PTFE grafts needed surgical revision or removal because of infection. Significantly more DHV grafts were surgically revised or removed because of aneurysms.

  11. Inactivation of enveloped and non-enveloped viruses in the process of chemical treatment and gamma irradiation of bovine-derived grafting materials.

    Science.gov (United States)

    Lee, Kwang-Il; Lee, Jung-Soo; Jung, Hong-Hee; Lee, Hwa-Yong; Moon, Seong-Hwan; Kang, Kyoung-Tak; Shim, Young-Bock; Jang, Ju-Woong

    2012-01-01

    Xenografts, unlike other grafting products, cannot be commercialized unless they conform to stringent safety regulations. Particularly with bovine-derived materials, it is essential to remove viruses and inactivate infectious factors because of the possibility that raw materials are imbrued with infectious viruses. The removal of the characteristics of infectious viruses from the bovine bone grafting materials need to be proved and inactivation process should satisfy the management provision of the Food and Drug Administration (FDA). To date, while most virus inactivation studies were performed in human allograft tissues, there have been almost no studies on bovine bone. To evaluate the efficacy of virus inactivation after treatment of bovine bone with 70% ethanol, 4% sodium hydroxide, and gamma irradiation, we selected a variety of experimental model viruses that are known to be associated with bone pathogenesis, including bovine parvovirus (BPV), bovine herpes virus (BHV), bovine viral diarrhea virus (BVDV), and bovine parainfluenza-3 virus (BPIV-3). The cumulative virus log clearance factor or cumulative virus log reduction factor for the manufacturing process was obtained by calculating the sum of the individual virus log clearance factors or log reduction factors determined for individual process steps with different physicochemical methods. The cumulative log clearance factors achieved by three different virus inactivation processes were as follows: BPV ≥ 17.73, BHV ≥ 20.53, BVDV ≥ 19.00, and BPIV-3 ≥ 16.27. On the other hand, the cumulative log reduction factors achieved were as follows: BPV ≥ 16.95, BHV ≥ 20.22, BVDV ≥ 19.27, and BPIV-3 ≥ 15.58. Treatment with 70% ethanol, 4% sodium hydroxide, or gamma irradiation was found to be very effective in virus inactivation, since all viruses were at undetectable levels during each process. We have no doubt that application of this established process to bovine bone graft manufacture will be

  12. Grafts for Ridge Preservation.

    Science.gov (United States)

    Jamjoom, Amal; Cohen, Robert E

    2015-08-07

    Alveolar ridge bone resorption is a biologic phenomenon that occurs following tooth extraction and cannot be prevented. This paper reviews the vertical and horizontal ridge dimensional changes that are associated with tooth extraction. It also provides an overview of the advantages of ridge preservation as well as grafting materials. A Medline search among English language papers was performed in March 2015 using alveolar ridge preservation, ridge augmentation, and various graft types as search terms. Additional papers were considered following the preliminary review of the initial search that were relevant to alveolar ridge preservation. The literature suggests that ridge preservation methods and augmentation techniques are available to minimize and restore available bone. Numerous grafting materials, such as autografts, allografts, xenografts, and alloplasts, currently are used for ridge preservation. Other materials, such as growth factors, also can be used to enhance biologic outcome.

  13. Grafts for Ridge Preservation

    Directory of Open Access Journals (Sweden)

    Amal Jamjoom

    2015-08-01

    Full Text Available Alveolar ridge bone resorption is a biologic phenomenon that occurs following tooth extraction and cannot be prevented. This paper reviews the vertical and horizontal ridge dimensional changes that are associated with tooth extraction. It also provides an overview of the advantages of ridge preservation as well as grafting materials. A Medline search among English language papers was performed in March 2015 using alveolar ridge preservation, ridge augmentation, and various graft types as search terms. Additional papers were considered following the preliminary review of the initial search that were relevant to alveolar ridge preservation. The literature suggests that ridge preservation methods and augmentation techniques are available to minimize and restore available bone. Numerous grafting materials, such as autografts, allografts, xenografts, and alloplasts, currently are used for ridge preservation. Other materials, such as growth factors, also can be used to enhance biologic outcome.

  14. Materials of 4. Spring School of Radiation Sterilization of Medical Materials, Grafts, Pharmaceutics and Cosmetics; Materialy 4. Wiosennej Szkoly Sterylizacji Radiacyjnej Sprzetu Medycznego, Przeszczepow, Farmaceutykow i Kosmetykow

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-01

    The state of art in well developed in Poland radiation technologies has been done. The legal and economical aspects have been discussed for radiation sterilization of health care products, drugs, biomaterials and grafts. Industrial plants and radiation procedures have been described. The perspectives for further development and other industrial applications have been also discussed.

  15. Development of a simple device enabling percutaneous flow regulation for a small vascular graft for a Blalock-Taussig shunt capable of flow regulation: complete translation of a review article originally published in Pediatric Cardiology and Cardiac Surgery (154-159, 2016: vol. 32).

    Science.gov (United States)

    Motohashi, Yoshikazu; Shimada, Ryo; Sasaki, Tomoyasu; Katsumata, Takahiro; Dan, Kazunori; Tsutsui, Yasuhiro; Nemoto, Shintaro

    2017-11-09

    The Blalock-Taussig shunt (BTS) operation is a cornerstone as initial palliative surgery for congenital heart disease with severely reduced pulmonary blood flow (PBF). The ideal PBF provided by BTS is crucial for an uneventful postoperative course, since excess PBF results in acute distress of the systemic circulation and insufficient PBF requires another BTS surgery. Therefore, the goal of this study was to develop a simple device to control the shunt graft flow percutaneously using a constrictor balloon connected to a subcutaneous port. The device consists of a cylindrical balloon and an anti-bending structure extension connected to the balloon center. A PTFE vascular graft wrapped by the device was connected to a simulated closed circuit to measure the relationship between pressure and blood flow while changing the inner volume of the balloon. In a beagle model of replacement of the right carotid artery, blood flow velocity was measured in the carotid artery after saline injection into the balloon. The blood flow velocity before and after balloon inflation was compared immediately after implantation of the device and at 3 months after implantation. The device provided good flow control by inflating and deflating the balloon ex vivo and in vivo for up to 3 months in a canine model with a small graft wrapped with the device. The simple device developed in this study may enable regulation of PBF through a small vascular graft and help to prevent severe morbidity and mortality in the clinical setting of BTS.

  16. Ingrowth of aorta vascular cells into basic fibroblast growth factor-impregnated vascular prosthesis material: A porcine and human in vitro study on blood vessel prosthesis healing

    NARCIS (Netherlands)

    Bas, J.M.A. van der; Quax, P.H.A.; Berg, A.C. van den; Hinsbergh, V.W.M. van; Bockel, J.H. van

    2002-01-01

    Objective: One of the most life-threatening vascular diseases is rupture of an abdominal aneurysm. The conventional treatment is based on surgical reconstruction. An alternative treatment is endovascular aneurysm repair (EVAR). Despite many advantages, one of the problems of EVAR is endoleakage from

  17. Differential effects of culture senescence and mechanical stimulation on the proliferation and leiomyogenic differentiation of MSC from different sources: implications for engineering vascular grafts.

    Science.gov (United States)

    Koobatian, Maxwell T; Liang, Mao-Shih; Swartz, Daniel D; Andreadis, Stelios T

    2015-04-01

    We examined the effects of senescence on the proliferation and leiomyogenic differentiation potential of mesenchymal stem cells (MSCs) isolated from bone marrow (BM-MSCs) or hair follicles (HF-MSCs). To this end, we compared ovine HF-MSCs and BM-MSCs in terms of their proliferation and differentiation potential to the smooth muscle cell lineage. We discovered that HF-MSCs are less susceptible to culture senescence compared with BM-MSCs. We hypothesized that application of mechanical forces may enhance the contractility and mechanical properties of vascular constructs prepared from senescent MSCs. Interestingly, HF-MSCs and BM-MSCs responded differently to changes in the mechanical microenvironment, suggesting that despite phenotypic similarities, MSCs from different anatomic locations may activate different pathways in response to the same microenvironmental factors. In turn, this may also suggest that cell-based tissue regeneration approaches may need to be tailored to the stem cell origin, donor age, and culture time for optimal results.

  18. Research on a Zn-Cu alloy as a biodegradable material for potential vascular stents application.

    Science.gov (United States)

    Niu, Jialin; Tang, Zibo; Huang, Hua; Pei, Jia; Zhang, Hua; Yuan, Guangyin; Ding, Wenjiang

    2016-12-01

    Zn-based alloys have been viewed as new potential materials for biodegradable implants, such as cardiovascular stents, mainly in consideration of their lower corrosion rate when compared with that of Mg alloys. In this study we developed a new Zinc-4wt.%Copper (Zn-4Cu) alloy as a biodegradable material. Hot extrusion was applied to Zn-4Cu to refine the microstructure and consequently improve its mechanical properties and corrosion resistance. After extrusion, dendritic CuZn5 phases were broken and distributed along the extrusion direction. The grains were refined obviously due to dynamical recrystallization. The yield strength (YS), ultimate tensile strength (UTS) and elongation of the as-extruded alloy are 250±10MPa, 270±10MPa and 51±2%, respectively. The corrosion rate of the as-extruded alloy in Hank's solution is about 9.41(±1.34)μmyear(-1). In vitro evaluation shows that Zn-4Cu presents acceptable toxicity to human endothelial cells, and could effectively inhibit bacteria adhesion and biofilm formation. The present study indicates that the as-extruded Zn-4Cu alloy exhibits excellent strength and ductility, uniform and slow degradation, good biocompatibility and significant antibacterial effect, which make it an excellent candidate material for biodegradable implants, especially for cardiovascular stents application. Copyright © 2016. Published by Elsevier B.V.

  19. Endothelial and smooth muscle cells derived from human cardiac explants demonstrate angiogenic potential and suitable for design of cell-containing vascular grafts.

    Science.gov (United States)

    Zakharova, I S; Zhiven', M K; Saaya, Sh B; Shevchenko, A I; Smirnova, A M; Strunov, A; Karpenko, A A; Pokushalov, E A; Ivanova, L N; Makarevich, P I; Parfyonova, Y V; Aboian, E; Zakian, S M

    2017-03-03

    Endothelial and smooth muscle cells are considered promising resources for regenerative medicine and cell replacement therapy. It has been shown that both types of cells are heterogeneous depending on the type of vessels and organs in which they are located. Therefore, isolation of endothelial and smooth muscle cells from tissues relevant to the area of research is necessary for the adequate study of specific pathologies. However, sources of specialized human endothelial and smooth muscle cells are limited, and the search for new sources is still relevant. The main goal of our study is to demonstrate that functional endothelial and smooth muscle cells can be obtained from an available source-post-surgically discarded cardiac tissue from the right atrial appendage and right ventricular myocardium. Heterogeneous primary cell cultures were enzymatically isolated from cardiac explants and then grown in specific endothelial and smooth muscle growth media on collagen IV-coated surfaces. The population of endothelial cells was further enriched by immunomagnetic sorting for CD31, and the culture thus obtained was characterized by immunocytochemistry, ultrastructural analysis and in vitro functional tests. The angiogenic potency of the cells was examined by injecting them, along with Matrigel, into immunodeficient mice. Cells were also seeded on characterized polycaprolactone/chitosan membranes with subsequent analysis of cell proliferation and function. Endothelial cells isolated from cardiac explants expressed CD31, VE-cadherin and VEGFR2 and showed typical properties, namely, cytoplasmic Weibel-Palade bodies, metabolism of acetylated low-density lipoproteins, formation of capillary-like structures in Matrigel, and production of extracellular matrix and angiogenic cytokines. Isolated smooth muscle cells expressed extracellular matrix components as well as α-actin and myosin heavy chain. Vascular cells derived from cardiac explants demonstrated the ability to stimulate

  20. VASCULAR DEMENTIA

    Directory of Open Access Journals (Sweden)

    Maria Alekseyevna Cherdak

    2010-01-01

    vascular cognitive disorders and vascular dementia (VD. The heterogeneity of vascular cognitive disorders, concurrence of vascular and neurodegenerative diseases are discussed. Data from studies of specific therapy for VD are given.

  1. In vivo quantitation of platelet deposition on human peripheral arterial bypass grafts using indium-111-labeled platelets. Effect of dipyridamole and aspirin

    Energy Technology Data Exchange (ETDEWEB)

    Pumphrey, C.W.; Chesebro, J.H.; Dewanjee, M.K.; Wahner, H.W.; Hollier, L.H.; Pairolero, P.C.; Fuster, V.

    1983-03-01

    Indium-111-labeled autologous platelets, injected 48 hours after operation, were used to evaluate the thrombogenicity of prosthetic material and the effect of platelet inhibitor therapy in vivo. Dacron double-velour (Microvel) aortofemoral artery bifurcation grafts were placed in 16 patients and unilateral polytetrafluoroethylene femoropopliteal grafts were placed in 10 patients. Half the patients in each group received platelet inhibitors before operation (dipyridamole, 100 mg 4 times a day) and after operation (dipyridamole, 75 mg, and acetylsalicylic acid, 325 mg 3 times a day); the rest of the patients served as control subjects. Five-minute scintigrams of the graft region were taken with a gamma camera interfaced with a computer 48, 72, and 96 hours after injection of the labeled platelets. Platelet deposition was estimated from the radioactivities of the grafts and expressed as counts per 100 pixels per microcurie injected. Dipyridamole and aspirin therapy significantly reduced the number of platelets deposited on Dacron grafts and prevented platelet accumulation over 3 days. With the small amount of platelet deposition on polytetrafluoroethylene femoropopliteal artery grafts even in control patients, platelet inhibitor therapy had no demonstrable effect on platelet deposition on these grafts. It is concluded that (1) platelet deposition on vascular grafts in vivo can be quantitated by noninvasive methods, and (2) dipyridamole and aspirin therapy reduced platelet deposition on Dacron aortofemoral artery grafts.

  2. Vascularized epiphyseal transplant.

    Science.gov (United States)

    Innocenti, Marco; Delcroix, Luca; Romano, G Federico; Capanna, Rodolfo

    2007-01-01

    In skeletally immature patients, the transfer of vascularized epiphysis along with a variable amount of adjoining diaphysis may provide the potential for growth of such a graft, preventing future limb length discrepancy. This article describes the authors' experience with the vascularized transfer of the proximal fibular epiphysis in the reconstruction of large bone defects including the epiphysis in a series of 27 patients ranging in age from 2 to 11 years. The follow-up, ranging from 2 to 14 years, has been long enough to allow some evaluation of the validity, indications, and limits of this reconstructive option.

  3. Graft union formation in artichoke grafting onto wild and cultivated cardoon: an anatomical study.

    Science.gov (United States)

    Trinchera, Alessandra; Pandozy, Gianmarco; Rinaldi, Simona; Crinò, Paola; Temperini, Olindo; Rea, Elvira

    2013-12-15

    In order to develop a non-chemical method such as grafting effective against well-known artichoke soil borne diseases, an anatomical study of union formation in artichoke grafted onto selected wild and cultivated cardoon rootstocks, both resistant to Verticillium wilt, was performed. The cardoon accessions Belgio (cultivated cardoon) and Sardo (wild cardoon) were selected as rootstocks for grafting combinations with the artichoke cv. Romolo. Grafting experiments were carried out in the autumn and spring. The anatomical investigation of grafting union formation was conducted by scanning electron microscopy (SEM) on the grafting portions at the 3rd, 6th, 10th, 12th day after grafting. For the autumn experiment only, SEM analysis was also performed at 30 d after grafting. A high affinity between artichoke scion and cardoon rootstocks was observed, with some genotype differences in healing time between the two bionts. SEM images of scion/rootstock longitudinal sections revealed the appearance of many interconnecting structures between the two grafting components just 3d after grafting, followed by a vascular rearrangement and a callus development during graft union formation. De novo formation of many plasmodesmata between scion and rootstock confirmed their high compatibility, particularly in the globe artichoke/wild cardoon combination. Moreover, the duration of the early-stage grafting process could be influenced not only by the scion/rootstock compatibility, but also by the seasonal conditions, being favored by lower temperatures and a reduced light/dark photoperiod. Copyright © 2013 Elsevier GmbH. All rights reserved.

  4. Revision of migrated pelvic acetabular components in THA with or without vascular involvement

    Directory of Open Access Journals (Sweden)

    Ștefan Cristea

    2016-05-01

    Full Text Available Purpose. The literature describes a high rate of mortality in cases of intrapelvic acetabular component migration, which is a rare but serious complication. Our aim is to establish and propose a treatment protocol according to our results and experience. Material and Methods. We performed eight (8 total hip revisions with acetabular cup migration between 2006 and 2012. A vascular graft was needed in four (4 of these cases. Two (2 cases were revisions after a spacer for infected arthroplasties. The protocol included the following: X-Ray examination (frontal and lateral views, CT angiography, a biological evaluation, a suitable pre-operative plan, at least six (6 units of blood stock, an experienced anesthesiologist, an experienced surgical team that included a vascular surgeon and a versatile arsenal of revision prostheses, bone grafts and vascular grafts. The anterolateral approach was generally used for hip revisions and the retroperitoneal approach in the dorsal decubitus position was used when vascular risk was involved. Results: The acetabular defect was reconstructed using bone grafts and tantalum revision cups in 4 cases, Burch-Schneider cages in 2 cases, a Kerboull ring in 1 case and a cementless oblong cup (Cotyle Espace in 1 case. In 4 cases, an iliac vessel graft procedure was conducted by the vascular surgeon. All patients survived the revision procedures and returned regularly for subsequent check-ups, during which they did not show any septic complications. Conclusions: Intrapelvic acetabular cup migration is a rare but serious complication that can occur after total hip arthroplasty in either septic or aseptic cases. An experienced, multidisciplinary team of surgeons should be involved in planning and conducting such complicated revisions.

  5. Uptake of radiolabeled leukocytes in prosthetic graft infection

    Energy Technology Data Exchange (ETDEWEB)

    Serota, A.I.; Williams, R.A.; Rose, J.G.; Wilson, S.E.

    1981-07-01

    The utility of radionuclide labeled leukocytes in the demonstration of infection within vascular prostheses was examined. The infrarenal aorta was replaced with a 3 cm Dacron graft in 12 dogs. On the third postoperative day, six of the animals received an intravenous injection of 10(8) Staphylococcus aureus. Labeled leukocyte scans were performed at postoperative days one and three, and then weekly for 8 weeks with indium-111 and technetium-99 labeled autologous leukocytes. When scans showed focal uptake of isotope in the area of prosthetic material, the grafts were aseptically excised and cultured on mannitol-salt agar. Both control and infected animals had retroperitoneal isotope activity in the immediate postoperative period that disappeared by the end of the first week. By the eighth postoperative week, all of the animals that received the bacteremic challenge had both radionuclide concentration in the region of the vascular prosthesis and S. aureus cultured subsequently from the perigraft tissues. None of the control animals had either radionuclide or bacteriologic evidence of infection at the eighth postoperative week. The radiolabeled leukocyte scan is a highly sensitive and specific technique, clinically applicable for the diagnosis of vascular prosthetic infections.

  6. ECM-Based Materials in Cardiovascular Applications: Inherent Healing Potential and Augmentation of Native Regenerative Processes

    Directory of Open Access Journals (Sweden)

    Anthony Callanan

    2009-10-01

    Full Text Available The in vivo healing process of vascular grafts involves the interaction of many contributing factors. The ability of vascular grafts to provide an environment which allows successful accomplishment of this process is extremely difficult. Poor endothelisation, inflammation, infection, occlusion, thrombosis, hyperplasia and pseudoaneurysms are common issues with synthetic grafts in vivo. Advanced materials composed of decellularised extracellular matrices (ECM have been shown to promote the healing process via modulation of the host immune response, resistance to bacterial infections, allowing re-innervation and reestablishing homeostasis in the healing region. The physiological balance within the newly developed vascular tissue is maintained via the recreation of correct biorheology and mechanotransduction factors including host immune response, infection control, homing and the attraction of progenitor cells and infiltration by host tissue. Here, we review the progress in this tissue engineering approach, the enhancement potential of ECM materials and future prospects to reach the clinical environment.

  7. The behavior of vascular smooth muscle cells and platelets onto epigallocatechin gallate-releasing poly(l-lactide-co-epsilon-caprolactone) as stent-coating materials.

    Science.gov (United States)

    Cho, Han Hee; Han, Dong-Wook; Matsumura, Kazuaki; Tsutsumi, Sadami; Hyon, Suong-Hyu

    2008-03-01

    Localized drug delivery from drug-eluting stents has been accepted as one of the most promising treatment methods for preventing restenosis after stenting. However, thrombosis, inflammation, and restenosis are still major problems for the utility of cardiovascular prostheses such as vascular grafts and stents. Epigallocatechin-3-O-gallate (EGCG), a major polyphenolic constituent of green tea, has been shown to have anti-thrombotic, anti-inflammatory and anti-proliferative activities. It was hypothesized that controlled release of EGCG from biodegradable poly(lactide-co-epsilon-caprolactone, PLCL) stent coatings would suppress migration and invasion of vascular smooth muscle cells (VSMCs) as well as platelet-mediated thrombosis. EGCG-releasing PLCL (E-PLCL) was prepared by blending PLCL with 5% EGCG. The surface morphology, roughness and melting temperature of PLCL were not changed despite EGCG addition. EGCG did, however, EGCG appreciably increase the hydrophilicity of PLCL. EGCG was found to be uniformly dispersed throughout E-PLCL without direct chemical interactions with PLCL. E-PLCL displayed diffusion controlled release of EGCG release for periods up to 34 days. E-PLCL significantly suppressed the migration and invasion of VSMCs as well as the adhesion and activation of platelets. E-PLCL coatings were able to smooth the surface of bare stents with neither cracks nor webbings after balloon expansion. The structural integrity of coatings was sufficient to resist delamination or destruction during 90% dilatation. These results suggest that EGCG-releasing polymers can be effectively applied for fabricating an EGCG-eluting vascular stent to prevent in-stent restenosis and thrombosis.

  8. Coronary Artery Bypass Grafting

    Science.gov (United States)

    ... Health Topics / Coronary Artery Bypass Grafting Coronary Artery Bypass Grafting What Is Coronary artery bypass grafting (CABG) ... multiple coronary arteries during one surgery. Coronary Artery Bypass Grafting Figure A shows the location of the ...

  9. The making of indigenous vascular prosthesis

    Directory of Open Access Journals (Sweden)

    Madathipat Unnikrishnan

    2016-01-01

    Full Text Available Background & objectives: Vascular illnesses are on the rise in India, due to increase in lifestyle diseases and demographic transition, requiring intervention to save life, organ or limbs using vascular prosthesis. The aim of this study was to develop indigenous large diameter vascular graft for treatment of patients with vascular pathologies. Methods: The South India Textile Research Association, at Coimbatore, Tamil Nadu, India, developed seamless woven polyester (Polyethylene terephthalate graft at its research wing. Further characterization and testing followed by clinical trials were conducted at Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India. Fifteen in vivo experiments were carried out in 1992-1994 in pigs as animal model. Controlled (phase I clinical trial in ten patients was performed along with control graft. Thereafter, phase II trial involved 22 patients who underwent multi-centre clinical trial in four centres across India. Results: Laboratory testing showed that polyester graft was non-toxic, non-leeching and non-haemolytic with preserved long-term quality, further confirming in pigs by implanting in thoracic aorta, comparable to control Dacron grafts. Perigraft incorporation and smooth neointima formation which are prime features of excellent healing characteristics, were noted at explantation at planned intervals. Subsequently in the phase I and II clinical trials, all patients had excellent recovery without mortality or device-related adverse events. Patients receiving the test graft were followed up for 10 and 5 years, respectively. Serial clinical, duplex scans and CT angiograms performed periodically confirmed excellent graft performance. Interpretation & conclusions: Indigenously developed Chitra vascular graft was comparable to commercially available Dacron graft, ready for clinical use at affordable cost to patients as against costly imported grafts.

  10. Real-time demonstration of split skin graft inosculation and integra dermal matrix neovascularization using confocal laser scanning microscopy.

    Science.gov (United States)

    Greenwood, John; Amjadi, Mahyar; Dearman, Bronwyn; Mackie, Ian

    2009-08-20

    During the first 48 hours after placement, an autograft "drinks" nutrients and dissolved oxygen from fluid exuding from the underlying recipient bed ("plasmatic imbibition"). The theory of inosculation (that skin grafts subsequently obtain nourishment via blood vessel "anastomosis" between new vessels invading from the wound bed and existing graft vessels) was hotly debated from the late 19th to mid-20th century. This study aimed to noninvasively observe blood flow in split skin grafts and Integra dermal regeneration matrix to provide further proof of inosculation and to contrast the structure of vascularization in both materials, reflecting mechanism. Observations were made both clinically and using confocal microscopy on normal skin, split skin graft, and Integra. The VivaScope allows noninvasive, real-time, in vivo images of tissue to be obtained. Observations of blood flow and tissue architecture in autologous skin graft and Integra suggest that 2 very different processes are occurring in the establishment of circulation in each case. Inosculation provides rapid circulatory return to skin grafts whereas slower neovascularization creates an unusual initial Integra circulation. The advent of confocal laser microscopy like the VivaScope 1500, together with "virtual" journals such as ePlasty, enables us to provide exciting images and distribute them widely to a "reading" audience. The development of the early Integra vasculature by neovascularization results in a large-vessel, high-volume, rapid flow circulation contrasting markedly from the inosculatory process in skin grafts and the capillary circulation in normal skin and merits further (planned) investigation.

  11. A comparison between the HeRO graft and conventional arteriovenous grafts in hemodialysis patients.

    Science.gov (United States)

    Nassar, George M; Glickman, Marc H; McLafferty, Robert B; Croston, J Kevin; Zarge, Joseph I; Katzman, Howard E; Peden, Eric K; Lawson, Jeffrey H; Martinez, Jeffrey M; Thackeray, Lisa

    2014-01-01

    Venous stenosis and occlusion are a major cause of vascular access dysfunction and failure. The HeRO Graft bypasses occlusion and traverses stenosis with outflow directly into the central venous circulation. A randomized, multicenter study was conducted to evaluate the efficacy and safety of the HeRO Graft relative to conventional AV grafts. The design was to enroll 143 patients in a 2:1 randomization ratio between HeRO and conventional AV control groups. Data on 72 subjects (52 HeRO Graft and 20 AV graft controls) were obtained. The HeRO Graft and control cohorts were comparable in baseline characteristics. Adequacy of dialysis, bacteremia rates, and adverse events were consistent between groups. Twelve month Kaplan-Meier estimates for primary and secondary patency rates were 34.8% and 67.6% in the HeRO Graft cohort, and 30.6% and 58.4% in the control cohort. There was no statistical difference in terms of patency between groups. The rates of intervention were 2.2/year for HeRO Graft and 1.6/year for the control (p = 0.100). Median days to loss of secondary patency was 238 for HeRO Graft versus 102 for the control (p = 0.032). The HeRO Graft appears to provide similar patency, adequacy of dialysis, and bacteremia rates to those of conventional AV grafts. © 2014 Wiley Periodicals, Inc.

  12. Experimental results and clinical impact of using autologous rectus fascia sheath for vascular replacement

    NARCIS (Netherlands)

    Kobori, Laszlo; Nemeth, Tibor; Nagy, Peter; Dallos, Gabor; Sotonyi, Peter; Fehervari, Imre; Nemes, Balazs; Gorog, Denes; Patonai, Attila; Monostory, Katalin; Doros, Attila; Sarvary, Enikoe; Fazakas, Janos; Gerlei, Zsuzsanna; Benkoe, Tamas; Piros, Laszlo; Jaray, Jeno; De Jong, Koert P.

    Vascular complications are major causes of graft failure in liver transplantation. The use of different vascular grafts is common but the results are controversial. The aim of this study was to create an 'ideal' arterial interponate for vascular replacements in the clinical field. An autologous,

  13. Analysis of risk factors for occlusions of a synthetic femoropopliteal bypass graft

    Directory of Open Access Journals (Sweden)

    Mirković Nikola

    2015-01-01

    Full Text Available Background/Aim. Femoropopliteal bypass is a revascularization technique of lower extremities with excellent outcome. The great saphenous vein is the best graft material, but if it is not adequate or has been removed, synthetic grafts are an useful alternative. Graft occlusion is the most significant complication with the most serious consequences. The aim of this study was to analyse predictive factors for the synthetic femoropopliteal bypass occlusions. Methods. This retrospective case-control study included all patients who underwent synthetic femoropopliteal bypass due to peripheral arterial occlusive disease at the Vascular Surgery Center, Clinical Center of Kragujevac, Serbia, from 2007 to 2013. The cases group were the patients with femoropopliteal graft occlusion (n = 44, with the control group consisted of the patients without such an outcome (n = 88. Results. Significant effects to occlusion were: concomitant cardiovascular disease (adjustedOR 27.05; 95% CI 4.74; 154.35, a type of femoropopliteal bypass (adjustedOR 16.50; 95% CI 4.05; 67.24, previous vascular intervention (adjustedOR 4.67; 95% CI 1.20; 18.14, clinical stage of the disease (adjustedOR 3.73; 95% CI 1.94; 7.18, administration of postoperative oral anticoagulant therapy (adjustedOR 0.05; 95% CI 0.01; 0.23 and the use of angiotensin converting enzyme inhibitors (adjustedOR 0.14; 95% CI 0.03; 0.70. A significant synergism was shown for the following combinations of the observed risk factors: type of femoropopliteal bypass and cardiovascular disease, type of femoropopliteal bypass and previous vascular intervention, previous vascular intervention and cardiovascular disease, previous vascular intervention and beta blockers, cardiovascular disease and diabetes, type of femoropopliteal bypass and antiaggregant therapy, clinical stage of disease and cardiovascular disease, previous vascular intervention and antiaggregant therapy. Conclusion. Concomitant cardiovascular disease

  14. Management Strategies in Hemodialysis Vascular Access

    NARCIS (Netherlands)

    J. van der Linden (Joke)

    2006-01-01

    textabstractSince the introduction of the AV fistula and the use of interposition graft little improvement has been made in the vascular access field. Still, vascular access related complications, are one of the most important reasons for patient hospitalization, morbidity and even mortality

  15. Reconstructive vascular surgery below the knee

    DEFF Research Database (Denmark)

    Rasmussen, L B; Jelnes, R; Sager, P

    1986-01-01

    In a series of 38 consecutive patients with advanced peripheral vascular disease (i.e. rest pain) reconstructive vascular surgery was performed with the distal anastomosis below the knee. Ankle/arm pressure index (AAI) was 0.28 (0.11-0.47) preoperatively; accumulated graft patency rate was 0.47 (SD...

  16. Bioprinting for vascular and vascularized tissue biofabrication.

    Science.gov (United States)

    Datta, Pallab; Ayan, Bugra; Ozbolat, Ibrahim T

    2017-03-15

    Bioprinting is a promising technology to fabricate design-specific tissue constructs due to its ability to create complex, heterocellular structures with anatomical precision. Bioprinting enables the deposition of various biologics including growth factors, cells, genes, neo-tissues and extra-cellular matrix-like hydrogels. Benefits of bioprinting have started to make a mark in the fields of tissue engineering, regenerative medicine and pharmaceutics. Specifically, in the field of tissue engineering, the creation of vascularized tissue constructs has remained a principal challenge till date. However, given the myriad advantages over other biofabrication methods, it becomes organic to expect that bioprinting can provide a viable solution for the vascularization problem, and facilitate the clinical translation of tissue engineered constructs. This article provides a comprehensive account of bioprinting of vascular and vascularized tissue constructs. The review is structured as introducing the scope of bioprinting in tissue engineering applications, key vascular anatomical features and then a thorough coverage of 3D bioprinting using extrusion-, droplet- and laser-based bioprinting for fabrication of vascular tissue constructs. The review then provides the reader with the use of bioprinting for obtaining thick vascularized tissues using sacrificial bioink materials. Current challenges are discussed, a comparative evaluation of different bioprinting modalities is presented and future prospects are provided to the reader. Biofabrication of living tissues and organs at the clinically-relevant volumes vitally depends on the integration of vascular network. Despite the great progress in traditional biofabrication approaches, building perfusable hierarchical vascular network is a major challenge. Bioprinting is an emerging technology to fabricate design-specific tissue constructs due to its ability to create complex, heterocellular structures with anatomical precision

  17. Clinical and radiographic evaluation of demineralized bone matrix (grafton as a bone graft material in the treatment of human periodontal intraosseous defects

    Directory of Open Access Journals (Sweden)

    Mahantesha

    2013-01-01

    Full Text Available Purpose: The purpose of this clinical trial was to evaluate the efficacy of demineralized bone matrix (DBM as a bone graft material in the treatment of human intrabony periodontal defects as compared with control defects treated by open flap debridement (OFD alone. Materials and Methods: A controlled clinical trial was carried out for a period of 9 months in 11 patients (4 males and 7 females with an age group of 25-50 years, contributing to a total of 30 defects. The selected defects were then randomly divided in to experimental sites (OFD + DBM and control sites (OFD alone. Probing depth, clinical attachment levels and position of the gingival margin were recorded at baseline 3, 6 and 9 months post-operatively. Standardized radiographs (parallel technique were also documented at these recall intervals. Results: On completion of 9 months, the mean percentage of probing depth reduction achieved in the experimental sites and control sites was 61.70%, 23.86% respectively. The mean percentage of clinical attachment level gain was 61.34% and 19.37% in the experimental and control sites respectively. In the experimental sites recession was observed to a lesser extent. Conclusion: The use of DBM was more effective than OFD in improving clinical parameters and radiographic bone fill as shown in the present study. However, there is a need for further long term studies.

  18. Photo-initiated grafting of gelatin/N-maleic acyl-chitosan to enhance endothelial cell adhesion, proliferation and function on PLA surface.

    Science.gov (United States)

    Zhu, Aiping; Zhao, Feng; Ma, Teng

    2009-07-01

    Vascular graft surface properties significantly affect adhesion, growth and function of endothelial cells (ECs). The bulk degradation property of poly(lactic acid) (PLA) makes it possible for it to be replaced by cellular materials and PLA is desirable as a scaffold material for vascular grafts. However, PLA has an unfavorable surface property for EC adhesion and proliferation due to the lack of a selective cell adhesion motif. Photo-initiated surface-grafting polymerization is a promising method for immobilizing certain biomacromolecules on material surfaces without compromising bulk properties. N-Maleic acyl-chitosan (NMCS) is a novel biocompatible amphiphilic derivative of chitosan with double bonds and can be initiated by ultraviolet light. In this study, gelatin was complexed with NMCS via hydrophobic interaction, and gel/NMCS complex thus formed was then grafted on the PLA surface to improve EC biocompatibility. X-ray photoelectron and Fourier transform infrared spectroscopy, and water contact angle measurement confirmed immobilization of the gel/NMCS complex on PLA surface. Moreover, the gel/NMCS modified PLA enhanced human umbilical vein endothelial cell (HUVEC) spreading and flattening, and promoted the expression of more structured CD31 and vWF compared to unmodified PLA film. Compared to the unmodified PLA surface, the HUVECs on the modified PLA surface had elevated uptake of acetylated low-density lipoprotein, and maintained the ability to modulate metabolic activity upon exposure to shear stress at 5dyncm(-2) by up-regulating nitric oxide and prostacyclin production. Cell retention was 1.6 times higher on the gel/NMCS-PLA surface, demonstrating its improved potential for hemocompatibility. These results indicate that photo-initiated surface-grafting of the biomimetic gel/NMCS complex is an effective method to modify material surfaces as vascular grafts.

  19. Stent graft placement for dysfunctional arteriovenous grafts

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Gyeong Sik [Dept. of Radiology, CHA Bundang Medical Center, College of Medicine, CHA University, Seongnam (Korea, Republic of); Shin, Byung Seok; Ohm, Joon Young; Ahn, Moon Sang [Chungnam National University Hospital, Daejeon (Korea, Republic of)

    2015-07-15

    This study aimed to evaluate the usefulness and outcomes of stent graft use in dysfunctional arteriovenous grafts. Eleven patients who underwent stent graft placement for a dysfunctional hemodialysis graft were included in this retrospective study. Expanded polytetrafluoroethylene covered stent grafts were placed at the venous anastomosis site in case of pseudoaneurysm, venous laceration, elastic recoil or residual restenosis despite the repeated angioplasty. The patency of the arteriovenous graft was evaluated using Kaplan-Meier analysis. Primary and secondary mean patency was 363 days and 741 days. Primary patency at 3, 6, and 12 months was 82%, 73%, and 32%, respectively. Secondary patency at the 3, 6, 12, 24, and 36 months was improved to 91%, 82%, 82%, 50%, and 25%, respectively. Fractures of the stent graft were observed in 2 patients, but had no effect on the patency. Stent graft placement in dysfunctional arteriovenous graft is useful and effective in prolonging graft patency.

  20. Lingual vascular canals of the interforaminal region of the mandible: evaluation with conventional tomography

    National Research Council Canada - National Science Library

    Liang, H; Frederiksen, N L; Benson, B W

    2004-01-01

    The presence of lingual vascular foramina and canals in the interforaminal region may increase the risk of surgical complications during implant placement, bone grafting procedures and osteodistraction...

  1. Sulfonated hydrocarbon graft architectures for cation exchange membranes

    DEFF Research Database (Denmark)

    Nielsen, Mads Møller; Jankova Atanasova, Katja; Hvilsted, Søren

    2013-01-01

    A synthetic strategy to hydrocarbon graft architectures prepared from a commercial polysulfone and aimed as ion exchange membrane material is proposed. Polystyrene is grafted from a polysulfone macroinitiator by atom transfer radical polymerization, and subsequently sulfonated with acetyl sulfate...

  2. Posterior repair with perforated porcine dermal graft

    Directory of Open Access Journals (Sweden)

    G. Bernard Taylor

    2008-02-01

    Full Text Available OBJECTIVE: To compare postoperative vaginal incision separation and healing in patients undergoing posterior repair with perforated porcine dermal grafts with those that received grafts without perforations. Secondarily, the tensile properties of the perforated and non-perforated grafts were measured and compared. MATERIALS AND METHODS: This was a non-randomized retrospective cohort analysis of women with stage II or greater rectoceles who underwent posterior repair with perforated and non-perforated porcine dermal grafts (PelvicolTM CR Bard Covington, GA USA. The incidence of postoperative vaginal incision separation (dehiscence was compared. A secondary analysis to assess graft tensile strength, suture pull out strength, and flexibility after perforation was performed using standard test method TM 0133 and ASTM bending and resistance protocols. RESULTS: Seventeen percent of patients (21/127 who received grafts without perforations developed vaginal incision dehiscence compared to 7% (5/71 of patients who received perforated grafts (p = 0.078. Four patients with vaginal incision dehiscence with non-perforated grafts required surgical revision to facilitate healing. Neither tensile strength or suture pull out strength were significantly different between perforated and non-perforated grafts (p = 0.81, p = 0.29, respectively. There was no difference in the flexibility of the two grafts (p = 0.20. CONCLUSION: Perforated porcine dermal grafts retain their tensile properties and are associated with fewer vaginal incision dehiscences.

  3. Cartilage oligomeric matrix protein enhances the vascularization of acellular nerves

    Directory of Open Access Journals (Sweden)

    Wei-ling Cui

    2016-01-01

    Full Text Available Vascularization of acellular nerves has been shown to contribute to nerve bridging. In this study, we used a 10-mm sciatic nerve defect model in rats to determine whether cartilage oligomeric matrix protein enhances the vascularization of injured acellular nerves. The rat nerve defects were treated with acellular nerve grafting (control group alone or acellular nerve grafting combined with intraperitoneal injection of cartilage oligomeric matrix protein (experimental group. As shown through two-dimensional imaging, the vessels began to invade into the acellular nerve graft from both anastomotic ends at day 7 post-operation, and gradually covered the entire graft at day 21. The vascular density, vascular area, and the velocity of revascularization in the experimental group were all higher than those in the control group. These results indicate that cartilage oligomeric matrix protein enhances the vascularization of acellular nerves.

  4. Metal Oxide Thin Films Grafted on Silica Gel Surfaces: Recent Advances on the Analytical Application of these Materials

    Directory of Open Access Journals (Sweden)

    Gushikem Yoshitaka

    2001-01-01

    Full Text Available In the highly dispersed MxOy monolayer film on a porous SiO2 surface, denoted as SiO2/MxOy, the Si-O-M covalent bond formed on the SiO2 surface restricts the mobility of the attached oxide resulting in coordinatively unsaturated metal oxides (LAS in addition to the Brønsted acid sites (BAS. The BAS arise from the MOH and SiOH groups, the latter due to the unreacted silanol groups. As the attached oxides are strongly immobilized on the surface, they are also thermally very stable. The amphoteric character of most of the attached oxides allows the immobilization of various chemical species, acid or bases, resulting in a wide application of these surface modified materials. In this work many of the recent applications of these MxOy coated silica surfaces are described, such as selective adsorbents, in preconcentration processes, as new packing material for use in HPLC, support for immobilization of enzymes, amperometric electrodes, sensors and biosensors

  5. Coronary arteries bypass grafting stenosis

    Directory of Open Access Journals (Sweden)

    Mahmoud Ebrahimi

    2014-12-01

    Full Text Available Coronary artery disease (CAD is a major global problem. In addition, it is higher risk of mortality for women more than men are when develop in female gender Atherosclerotic plaques consist of deposits of fatty material in the tunica intima. The role of inflammatory process in CAD has been known from 1980’s. Several studies investigated the innate immunity and adaptive immunity roles in atherosclerosis and they concluded that it plays a key role in atherosclerosis. Coronary artery bypass grafting (CABG is a widely used method for the treatment of CAD. Based on the literature, CABG is the most common surgical operation done worldwide. In During the first 10 years after CABG, up to 50% of saphenous grafts will occlude. Graft restenosis is beginning with acute thrombosis, intima hyperplasia, and plaque formation. In this review, some molecular pathways of graft failure and restenosis such as apoptosis and nuclear factor kappa B (NF-ĸB are described.

  6. Argus II retinal prosthesis implantation with scleral flap and autogenous temporalis fascia as alternative patch graft material: a 4-year follow-up

    Directory of Open Access Journals (Sweden)

    Matet A

    2016-08-01

    Full Text Available Alexandre Matet,1,2 Nawel Amar,1,2 Saddek Mohand-Said,1–4 José-Alain Sahel,1–7 Pierre-Olivier Barale1,2 1INSERM and DHOS, CHNO des Quinze-Vingts, 2Sorbonne Universités, UPMC Univ Paris 6, Institut de la Vision, 3INSERM, 4CNRS, Paris, France; 5Institute of Ophthalmology, University College London, London, UK; 6Fondation Ophtalmologique Adolphe de Rothschild, 7Académie des Sciences, Institut de France, Paris, France Introduction: The Argus II retinal prosthesis is composed of an epiretinal electrode array positioned over the macula and connected to an extrascleral electronics case via a silicone cable, running through a sclerotomy. During implantation, the manufacturer recommends to cover the sclerotomy site with a patch of processed human pericardium to prevent postoperative hypotony and conjunctival erosion by the underlying electronics case. Due to biomedical regulations prohibiting the use of this material in France, we developed an alternative technique combining a scleral flap protecting the sclerotomy and an autogenous graft of superior temporalis fascia overlying the electronics case. Methods: The purpose of this study is to describe the 4-year outcomes of this modified procedure in three subjects who underwent Argus II Retinal Prosthesis System implantation. Clinical data consisting of intraocular pressure measurements and tolerance in terms of conjunctival erosion or inflammation were retrospectively assessed over a 4-year postoperative follow-up. Results: None of the three patients implanted with the modified technique developed ocular hypotony over 4 years. A normal, transient conjunctival inflammation occurred during the first postoperative month but conjunctival erosion was not observed in any of the three patients over 4 years. Four years after implantation, the autogenous temporalis fascia graft remained well tolerated and the retinal prosthesis was functional in all three patients. Conclusion: The combination of an

  7. Successful endovascular treatment of a hemodialysis graft pseudoaneurysm by covered stent and direct percutaneous thrombin injection.

    LENUS (Irish Health Repository)

    Keeling, Aoife N

    2011-07-25

    Vascular access for hemodialysis remains a challenge for nephrologists, vascular surgeons, and interventional radiologists alike. Arteriovenous fistula and synthetic grafts remain the access of choice for long-term hemodialysis; however, they are subject to complications from infection and repeated needle cannulation. Pseudoaneurysms are an increasingly recognized adverse event. At present, there are many minimally invasive methods to repair these wall defects. We present a graft pseudoaneurysm, which required a combination of endovascular stent graft placement and percutaneous thrombin injection for successful occlusion.

  8. Adventitial cystic disease of the popliteal artery treated by bypass graft utilizing the short saphenous vein: A case report.

    Science.gov (United States)

    Miyake, Katsunori; Sawamura, Naoki; Ikegaya, Yuki; Isogai, Naoko; Kawachi, Jun; Shimoyama, Rai; Fukai, Ryuta; Kashiwagi, Hiroyuki; Ogino, Hidemitsu

    2017-01-01

    Adventitial cystic disease is relatively rare vascular disease, frequently occurred in the popliteal artery. No definitive treatment has been established yet. A 53-year-old woman presenting intermittent claudication of the right leg was diagnosed as adventitial cystic disease of popliteal artery. Percutaneous balloon dilation yielded an immediate recurrence. The disease was successfully treated by bypass grafting utilizing the short saphenous vein to replace the part of the popliteal artery containing the adventitial cyst. No postoperative complication was found six months after surgery. Comparing to a great saphenous vein, a short saphenous vein as a material of bypass graft has a significant advantage, as only a single surgical field is necessary. We propose that bypass graft surgery employing a short saphenous vein is worth considering as a treatment of adventitial cystic disease at the popliteal artery. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. A multifunctional bioactive material that stimulates osteogenesis and promotes the vascularization bone marrow stem cells and their resistance to bacterial infection.

    Directory of Open Access Journals (Sweden)

    Chuang Ma

    Full Text Available The main limitation of tissue engineering lies in the inability to stimulate osteogenesis, angiogenesis of stem cells and broad-spectrum antimicrobial activity. However, the development of multifunctional bioactive materials with these capabilities remains a great challenge. In this study, we prepared mesoporous silica nanoparticles encapsulated with silver nanocrystals (AG-MSN with uniform sphere size and mesopores. Platelet-derived growth factor BB (PDGF-BB was effectively loaded in the AG-MSN mesopores (P-AG-MSN. The silicon ions (Si released by P-AG-MSN stimulate osteogenic differentiation of bone marrow stromal cells (BMSC by activating the alkaline phosphatase (ALP activity of bone-related genes and increasing protein (OCN, RUNX2 and OPN expression. Ag+ ions could be slowly released from the interior of the shell, highlighting their durable antibacterial activity. The sustained release of PDGF-BB from P-AG-MSN stimulated the angiogenic differentiation of BMSC, as indicated by the enhanced secretion of vascular endothelial growth factor (VEGF, HIF-1α, HGF and ANG-1 and protein expression. Our results show that P-AG-MSN can clearly promote BMSC osteostimulation and vascularization. This research serves as a preliminary study of the utilization of this multifunctional mixture to fabricate a new active biological scaffold that integrates BMSC osteostimulation, vascularization and bactericidal effects by 3D printing technology.

  10. Carboxylic acid-grafted mesoporous material and its high catalytic activity in one-pot three-component coupling reaction

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Ruth; Bhaumik, Asim [Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Dutta, Saikat [Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2014-11-01

    A new carboxylic acid functionalized mesoporous organic polymer has been synthesized via in situ radical polymerization of divinylbenzene and acrylic acid using a mesoporous silica as a seed during the polymerization process under solvothermal conditions. The mesoporous material MPDVAA-1 has been thoroughly characterized employing powder XRD, solid state {sup 13}C cross polarization magic angle spinning-nuclear magnetic resonance, FT-IR spectroscopy, N{sub 2} sorption, HR-TEM, and NH{sub 3} temperature programmed desorption-thermal conductivity detector (TPD-TCD) analysis to understand its porosity, chemical environment, bonding, and surface properties. The mesoporous polymer was used as a catalyst for a three comp onent Biginelli condensation between various aldehydes, β-keto esters, and urea/thioureas to give 3,4-dihydropyrimidine-2(1H)-ones. The reactions were carried out under conventional heating as well as solvent-free microwave irradiation of solid components, and in both the cases, the mesoporous polymer MPDVAA-1 proved to be a powerful, robust, and reusable catalyst with high catalytic efficiency.

  11. Carboxylic acid-grafted mesoporous material and its high catalytic activity in one-pot three-component coupling reaction

    Directory of Open Access Journals (Sweden)

    Ruth Gomes

    2014-11-01

    Full Text Available A new carboxylic acid functionalized mesoporous organic polymer has been synthesized via in situ radical polymerization of divinylbenzene and acrylic acid using a mesoporous silica as a seed during the polymerization process under solvothermal conditions. The mesoporous material MPDVAA-1 has been thoroughly characterized employing powder XRD, solid state 13C cross polarization magic angle spinning-nuclear magnetic resonance, FT-IR spectroscopy, N2 sorption, HR-TEM, and NH3 temperature programmed desorption-thermal conductivity detector (TPD-TCD analysis to understand its porosity, chemical environment, bonding, and surface properties. The mesoporous polymer was used as a catalyst for a three comp onent Biginelli condensation between various aldehydes, β-keto esters, and urea/thioureas to give 3,4-dihydropyrimidine-2(1H-ones. The reactions were carried out under conventional heating as well as solvent-free microwave irradiation of solid components, and in both the cases, the mesoporous polymer MPDVAA-1 proved to be a powerful, robust, and reusable catalyst with high catalytic efficiency.

  12. Inflorescence stem grafting made easy in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Nisar Nazia

    2012-12-01

    Full Text Available Abstract Background Plant grafting techniques have deepened our understanding of the signals facilitating communication between the root and shoot, as well as between shoot and reproductive organs. Transmissible signalling molecules can include hormones, peptides, proteins and metabolites: some of which travel long distances to communicate stress, nutrient status, disease and developmental events. While hypocotyl micrografting techniques have been successfully established for Arabidopsis to explore root to shoot communications, inflorescence grafting in Arabidopsis has not been exploited to the same extent. Two different strategies (horizontal and wedge-style inflorescence grafting have been developed to explore long distance signalling between the shoot and reproductive organs. We developed a robust wedge-cleft grafting method, with success rates greater than 87%, by developing better tissue contact between the stems from the inflorescence scion and rootstock. We describe how to perform a successful inflorescence stem graft that allows for reproducible translocation experiments into the physiological, developmental and molecular aspects of long distance signalling events that promote reproduction. Results Wedge grafts of the Arabidopsis inflorescence stem were supported with silicone tubing and further sealed with parafilm to maintain the vascular flow of nutrients to the shoot and reproductive tissues. Nearly all (87% grafted plants formed a strong union between the scion and rootstock. The success of grafting was scored using an inflorescence growth assay based upon the growth of primary stem. Repeated pruning produced new cauline tissues, healthy flowers and reproductive siliques, which indicates a healthy flow of nutrients from the rootstock. Removal of the silicone tubing showed a tightly fused wedge graft junction with callus proliferation. Histological staining of sections through the graft junction demonstrated the differentiation of

  13. Outcomes of AV Fistulas and AV Grafts after Interventional Stent-Graft Deployment in Haemodialysis Patients

    Energy Technology Data Exchange (ETDEWEB)

    Schmelter, Christopher, E-mail: christopher.schmelter@klinikum-ingolstadt.de; Raab, Udo, E-mail: udo.raab@klinikum-ingolstadt.de [Klinikum Ingolstadt, Department of Diagnostic and Interventional Radiology (Germany); Lazarus, Friedrich, E-mail: friedrich.lazarus@klinikum-ingolstadt.de [Klinikum Ingolstadt, Department of Nephrology (Germany); Ruppert, Volker, E-mail: volker.ruppert@klinikum-ingolstadt.de [Klinikum Ingolstadt, Department of Vascular Surgery (Germany); Vorwerk, Dierk, E-mail: dierk.vorwerk@klinikum-ingolstadt.de [Klinikum Ingolstadt, Department of Diagnostic and Interventional Radiology (Germany)

    2015-08-15

    PurposeThe study was designed to assess outcomes of arteriovenous (AV) accesses after interventional stent-graft deployment in haemodialysis patients.Materials and Methods63 haemodialysis patients with 66 AV fistulas and AV grafts were treated by interventional stent-graft deployment from 2006 to 2012 at our hospital. Data of these patients were retrospectively analysed for location of deployed stent-grafts, occurrence and location of (re-)stenosis and (re-)thrombosis. Complex stenosis was the most frequent indication for stent-graft deployment (45.5 %), followed by complications of angioplasty with vessel rupture or dissection (31.8 %).ResultsA high rate of procedural success was achieved (98.5 %). The most frequent location of the deployed stent-graft was the draining vein (66.7 %). Stent-graft deployment was more frequent in AV grafts than in AV fistulas. Primary patency was 45.5 % at 6 month, 31.3 % at 12 month and 19.2 % at 24 month. Primary patency was significantly better for AV fistulas than for AV grafts with deployed stent-grafts. Patency of the deployed stent-graft was much better than overall AV access primary patency with deployed stent-graft. Re-stenosis with thrombosis was the most frequent indication for re-intervention. Most frequent location of re-stenosis was the draining vein (37.1 %), followed by stenosis at the AV access (29.5 %) and the deployed stent-graft (23.5 %).ConclusionRe-stenosis and re-thrombosis remain frequent in AV fistulas and AV grafts in haemodialysis patients despite stent-graft deployment. Re-stenosis of the deployed stent-graft is, only in the minority of the cases, responsible for AV access dysfunction.

  14. Effect of a Particulate and a Putty-Like Tricalcium Phosphate-Based Bone-grafting Material on Bone Formation, Volume Stability and Osteogenic Marker Expression after Bilateral Sinus Floor Augmentation in Humans.

    Science.gov (United States)

    Knabe, Christine; Adel-Khattab, Doaa; Kluk, Esther; Struck, Rainer; Stiller, Michael

    2017-07-29

    This study examines the effect of a hyaluronic acid (HyAc) containing tricalcium phosphate putty scaffold material (TCP-P) and of a particulate tricalcium phosphate (TCP-G) graft on bone formation, volume stability and osteogenic marker expression in biopsies sampled 6 months after bilateral sinus floor augmentation (SFA) in 7 patients applying a split-mouth design. 10% autogenous bone chips were added to the grafting material during surgery. The grain size of the TCP granules was 700 to 1400 µm for TCP-G and 125 to 250 µm and 500 to 700 µm (ratio 1:1) for TCP-P. Biopsies were processed for immunohistochemical analysis of resin-embedded sections. Sections were stained for collagen type I (Col I), alkaline phosphatase (ALP), osteocalcin (OC) and bone sialoprotein (BSP). Furthermore, the bone area and biomaterial area fraction were determined histomorphometrically. Cone-beam CT data recorded after SFA and 6 months later were used for calculating the graft volume at these two time points. TCP-P displayed more advantageous surgical handling properties and a significantly greater bone area fraction and smaller biomaterial area fraction. This was accompanied by significantly greater expression of Col I and BSP and in osteoblasts and osteoid and a less pronounced reduction in grafting volume with TCP-P. SFA using both types of materials resulted in formation of sufficient bone volume for facilitating stable dental implant placement with all dental implants having been in function without any complications for 6 years. Since TCP-P displayed superior surgical handling properties and greater bone formation than TCP-G, without the HyAc hydrogel matrix having any adverse effect on bone formation or graft volume stability, TCP-P can be regarded as excellent grafting material for SFA in a clinical setting. The greater bone formation observed with TCP-P may be related to the difference in grain size of the TCP granules and/or the addition of the HyAc.

  15. Construction and evaluation of nitric oxide generating vascular graft material loaded with organoselenium catalyst via layer-by-layer self-assembly

    National Research Council Canada - National Science Library

    AN Jun CHEN SiYuan GAO JingChen ZHANG Xu WANG YuanYuan LI YanDong MIKHALOVSKY Sergey KONG DeLing WANG ShuFang

    2015-01-01

    ... (NO) was prepared in this study. Organoselenium immobilized polyethyleneimine as NO donor catalyst and sodium alginate were alternately loaded onto the surface of electrospun polycaprolactone matrix via electrostatic layer-by-layer self-assembly...

  16. Vascular Cures

    Science.gov (United States)

    ... is the first national program to bring the power of the patient to vascular research and care. ... Our recent national Vascular Research Summit brought together leaders from 31 institutions to generate collaborative projects for ...

  17. Transformation of nonvascular acellular tissue matrices into durable vascular conduits.

    Science.gov (United States)

    Clarke, D R; Lust, R M; Sun, Y S; Black, K S; Ollerenshaw, J D

    2001-05-01

    Prosthetic grafts commonly used for vascular reconstruction are limited to synthetics and cross-linked tissue grafts. Within these devices, graft infections are common, compliance mismatch is significant, and handling qualities are poor. Natural biological tissues that are unfixed have been shown to resist infections and be durable and compliant. A natural biological matrix that could be remodeled appropriately after implantation would be a desirable graft for vascular reconstruction. SynerGraft tissue engineering strategies have been used to minimize antigenicity and produce stable unfixed vascular grafts from nonvascular bovine tissues. These grafts have replaced the abdominal aortas of 8 dogs that have been followed for up to 10 months. Early evaluation indicates rapid recellularization by recipient smooth muscle actin positive cells, which become arranged circumferentially, into the media. Arterioles were present in the adventitial areas and endothelial cells were seen to cover lumenal surfaces. After 10 months, grafts were patent and not aneurysmal. These data indicate that SynerGraft processing of animal tissues is capable of producing stable vascular conduits that exhibit long-term functionality in other species.

  18. Guided bone regeneration using autogenous tooth bone graft in implant therapy: case series.

    Science.gov (United States)

    Kim, Young-Kyun; Kim, Su-Gwan; Bae, Ji-Hyun; Um, In-Woong; Oh, Ji-Su; Jeong, Kyung-In

    2014-04-01

    Recently, techniques have been reported that involve the preparation of extracted teeth from patients used as particulated bone graft materials for bone graft purposes. For implant placement and bone graft, autogenous teeth bone graft materials were used in 15 patients, and clinically excellent results were obtained. In histological examination, favorable bony healing by osteoconduction was observed.

  19. Comparison of Modified Chandler, Roller Pump, and Ball Valve Circulation Models for In Vitro Testing in High Blood Flow Conditions: Application in Thrombogenicity Testing of Different Materials for Vascular Applications

    Directory of Open Access Journals (Sweden)

    Wim van Oeveren

    2012-01-01

    We concluded that the Hemobile minimally affects blood and could be adjusted to high blood flows, simulating arterial shear stress. The Hemobile was used to measure hemocompatibility of graft material and showed Dyneema Purity UHMWPE fiber in many ways more hemocompatible than ePTFE and PET.

  20. Feasibility of the Use of RapiGraft and Skin Grafting in Reconstructive Surgery

    Directory of Open Access Journals (Sweden)

    Jung Dug Yang

    2016-09-01

    Full Text Available BackgroundSkin grafting is a relatively simple and thus widely used procedure. However, the elastic and structural quality of grafted skin is poor. Recently, various dermal substitutes have been developed to overcome this disadvantage of split-thickness skin grafts. The present study aims to determine the feasibility of RapiGraft as a new dermal substitute.MethodsThis prospective study included 20 patients with partial- or full-thickness skin defects; the patients were enrolled between January 2013 and March 2014. After skin defect debridement, the wound was divided into two parts by an imaginary line. Split-thickness skin grafting alone was performed on one side (group A, and RapiGraft and split-thickness skin grafting were used on the other side (group B. All patients were evaluated using photographs and self-questionnaires. The Manchester scar scale (MSS, a chromameter, and a durometer were used for the scar evaluation. The average follow-up period was 6 months.ResultsThe skin graft take rates were 93% in group A and 89% in group B, a non-significant difference (P=0.082. Statistically, group B had significantly lower MSS, vascularity, and pigmentation results than group A (P<0.05 for all. However, the groups did not differ significantly in pliability (P=0.155.ConclusionsThe present study indicates that a simultaneous application of RapiGraft and a split-thickness skin graft is safe and yields improved results. Therefore, we conclude that the use of RapiGraft along with skin grafting will be beneficial for patients requiring reconstructive surgery.

  1. The surgical approach and source of bone graft for symptomatic nonunion of the scaphoid.

    Science.gov (United States)

    Hull, W J; House, J H; Gustillo, R B; Kleven, L; Thompson, W

    1976-01-01

    In 2 groups of patients treated by bone grafting for scaphoid nonunions, one group had a dorsal or dorsolateral surgical approach with a bone graft from the radius while the other group had a volar approach with an iliac graft. The best results were obtained with an iliac graft. Through the volar approach it is relatively easy to avoid damage to the scaphoid arterial supply. A small proximal vascular pole led to a failure rate of 36%.

  2. Chemically cross-linked and grafted cyclodextrin hydrogels: from nanostructures to drug-eluting medical devices.

    Science.gov (United States)

    Concheiro, Angel; Alvarez-Lorenzo, Carmen

    2013-08-01

    The unique ability of cyclodextrins (CDs) to form inclusion complexes can be transmitted to polymeric networks in which CDs are chemically grafted or cross-linked. Combination of CDs and hydrogels in a single material leads to synergic properties: the hydrophilic network enhances biocompatibility and prevents dilution in the physiological medium increasing the stability of the inclusion complexes, while CDs finely tune the mechanical features and the stimuli-responsiveness and provide affinity-based regulation of drug loading and release. Therefore, CD-functionalized materials are opening new perspectives in pharmacotherapy, emerging as advanced delivery systems (DDS) for hydrophobic and hydrophilic drugs to be administered via almost any route. Medical devices (catheters, prosthesis, vascular grafts, bone implants) can also benefit from surface grafting or thermofixation of CDs. The present review focuses on the approaches tested to synthesize nano- to macro-size covalently cross-linked CD networks: i) direct cross-linking through condensation with di- or multifunctional reagents, ii) copolymerization of CD derivatives with acrylic/vinyl monomers, and iii) grafting of CDs to preformed medical devices. Examples of the advantages of having the CDs chemically bound among themselves and to substrates are provided and their applicability in therapeutics discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Biograft-HT ® as a bone graft material in the treatment of periodontal vertical defects and its clinical and radiological evaluation: Clinical study

    Directory of Open Access Journals (Sweden)

    Chandrashekar K

    2009-01-01

    Full Text Available Aim: To determine the efficacy of Biograft-HT® as a bone graft material in the treatment of vertical defects in generalized chronic periodontitis patients and their clinical and radiological evaluation. Patients and Methods: Twenty patients diagnosed with generalized chronic periodontitis having two or more vertical defects were selected for this study. Clinical parameters like plaque index, gingival index, probing pocket depth and clinical attachment levels were recorded at different points of time over six months. Radiographic evaluation included the depth of the bone defect and the percentage of bone defect fill and was carried out for both the groups at baseline, three months and six months. After recording clinical parameters and administering phase -1 therapy, the sites were randomly treated either with Biograft- HT® or open flap debridement only. Results: At the end of six months there was a significant reduction in the plaque and gingival scores in both test and control groups. There was 64% decrease in probing pocket depth for the test site as compared to 54.52% decrease seen for the control group. Similarly there was an 84.82% gain in clinical attachment level from the baseline to six months post operatively for the experimental group in comparison to 68.83% gain for the control group. Furthermore, 43.57% bone fill was observed for the experimental site whereas only 17.98% of bone fill was evident in the control site. Conclusion: Biograft -HT improves healing outcomes, leads to a reduction of probing depth, a resolution of osseous defects and a gain in clinical attachment, compared with open flap debridement by itself.

  4. An unusual case of fistula formation and thrombosis between arteriovenous graft and a native vein

    Directory of Open Access Journals (Sweden)

    Young Sub Kim

    2016-03-01

    Full Text Available Arteriovenous graft for hemodialysis vascular access is a widely used technique with many advantages. However, it has crucial complications with graft thrombosis and infection. We recently experienced an unusual case of arteriovenous graft complication involving graft thrombosis related to fistula formation between the graft and the natural vein with infection. We diagnosed this condition using Doppler ultrasound and computed tomography angiography. Successful surgical treatment including partial graft excision and creation of a secondary arteriovenous fistula using an inadvertently dilated cephalic vein was performed. The dialysis unit staff should keep this condition in mind and try to prevent this complication.

  5. A Novel Seeding and Conditioning Bioreactor for Vascular Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Julia Schulte

    2014-07-01

    Full Text Available Multiple efforts have been made to develop small-diameter tissue engineered vascular grafts using a great variety of bioreactor systems at different steps of processing. Nevertheless, there is still an extensive need for a compact all-in-one system providing multiple and simultaneous processing. The aim of this project was to develop a new device to fulfill the major requirements of an ideal system that allows simultaneous seeding, conditioning, and perfusion. The newly developed system can be actuated in a common incubator and consists of six components: a rotating cylinder, a pump, a pulse generator, a control unit, a mixer, and a reservoir. Components that are in direct contact with cell media, cells, and/or tissue allow sterile processing. Proof-of-concept experiments were performed with polyurethane tubes and collagen tubes. The scaffolds were seeded with fibroblasts and endothelial cells that were isolated from human saphenous vein segments. Scanning electron microscopy and immunohistochemistry showed better seeding success of polyurethane scaffolds in comparison to collagen. Conditioning of polyurethane tubes with 100 dyn/cm2 resulted in cell detachments, whereas a moderate conditioning program with stepwise increase of shear stress from 10 to 40 dyn/cm2 induced a stable and confluent cell layer. The new bioreactor is a powerful tool for quick and easy testing of various scaffold materials for the development of tissue engineered vascular grafts. The combination of this bioreactor with native tissue allows testing of medical devices and medicinal substances under physiological conditions that is a good step towards reduction of animal testing. In the long run, the bioreactor could turn out to produce tissue engineered vascular grafts for human applications “at the bedside”.

  6. FY1995 new technology of artificial organ materials which can induce host biocompatibility; 1995 nendo jinko zokiyo seitai kino fukatsukagata sozai no kaihatsu gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    The aim of this project is to produce a highly biocompatible materials for next generation's artificial organs using the following methods: 1, Micromodification of polymer materials. 2, Biocompatible treatment for biological materials. 3, Application of bioabsorbable materials. 4, Bioactive substance immobilization. and 5, Use of autologous tissue as artificial organ materials. As a synthetic polymer material, microporous polyurethane was used for a small diameter vascular prosthesis. The graft with this technology was successfully implanted in rat abdomical aortic position. The graft of 1.5 mm in internal diameter and 10 cm in length showed excellent patency with nice endothelialisation. As a biological material, microfibers of collagen was used for a sealing substance of vascular prothesis. The microfibers absorbed a large amount of water, which could prevent blood leakage from the graft wall. The graft showed non-thrombogenic property and excellent host cell affinity, resulted in rapid neointima formation. As to autologous tissue, bone marrow was used, since marrow cells can differentiate into any mesenchimal cells with synthesis of growth factors. Marrow cell transplanted vascular prothesis showed rapid capillary ingrowth. These results indicated that the newly designed materials had suitable properties for materials of next generation's artificial organs. (NEDO)

  7. FY1995 new technology of artificial organ materials which can induce host biocompatibility; 1995 nendo jinko zokiyo seitai kino fukatsukagata sozai no kaihatsu gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    The aim of this project is to produce a highly biocompatible materials for next generation's artificial organs using the following methods: 1, Micromodification of polymer materials. 2, Biocompatible treatment for biological materials. 3, Application of bioabsorbable materials. 4, Bioactive substance immobilization. and 5, Use of autologous tissue as artificial organ materials. As a synthetic polymer material, microporous polyurethane was used for a small diameter vascular prosthesis. The graft with this technology was successfully implanted in rat abdomical aortic position. The graft of 1.5 mm in internal diameter and 10cm in length showed excellent patency with nice endothelialisation. As a biological material, microfibers of collagen was used for a sealing substance of vascular prothesis. The microfibers absorbed a large amount of water, which could prevent blood leakage from the graft wall. The graft showed non-thrombogenic property and excellent host cell affinity, resulted in rapid neointima formation. As to autologous tissue, bone marrow was used, since marrow cells can differentiate into any mesenchimal cells with synthesis of growth factors. Marrow cell transplanted vascular prothesis showed rapid capillary ingrowth. These results indicated that the newly designed materials had suitable properties for materials of next generation's artificial organs. (NEDO)

  8. Healing of cortical bone grafts in athymic rats

    Energy Technology Data Exchange (ETDEWEB)

    Kirkeby, O.J.; Nordsletten, L.; Skjeldal, S. (Institute for Surgical Research, University of Oslo, Oslo (Norway))

    1992-01-01

    We studied healing of allogeneic and syngeneic cortical tibial segment grafts in athymic and normal rats. After 3, 6, and 12 weeks, the weight, circulation; and mineralization rate of the healing segment, and mechanical strength and stiffness of the healing tibia were measured. There were no differences between allogeneic and syngeneic grafts in athymic and normal animals at 3 or 6 weeks. After 12 weeks, the vascularization and mineralization of the grafts, but not of the surrounding callus, were smaller in the allogeneic grafts in the normal recipients than in the other groups. Also after 12 weeks, the stiffness of the healing tibiae was less in allogeneic grafts in normal recipients than in the other groups. The strength of the allogeneic grafts was less than the strength of the syngeneic grafts in both athymic and normal recipients. This suggests that T-cell-mediated rejection is responsible for decreased vascularization and mineralization of alogenecic bone and that the difference in strength between allogeneic and syngeneci grafts in not due to T-lymphocyte graft rejection. (au).

  9. Grafting of gelatin on electrospun poly(caprolactone) nanofibers to improve endothelial cell spreading and proliferation and to control cell Orientation.

    Science.gov (United States)

    Ma, Zuwei; He, Wei; Yong, Thomas; Ramakrishna, S

    2005-01-01

    We modified the surface of electrospun poly(caprolactone) (PCL) nanofibers to improve their compatibility with endothelial cells (ECs) and to show the potential application of PCL nanofibers as a blood vessel tissue-engineering scaffold. Nonwoven PCL nanofibers (PCL NF) and aligned PCL nanofibers (APCL NF) were fabricated by electrospinning technology. To graft gelatin on the nanofiber surface, PCL nanofibers were first treated with air plasma to introduce -COOH groups on the surface, followed by covalent grafting of gelatin molecules, using water-soluble carbodiimide as the coupling agent. The chemical change in the material surface during surface modification was confirmed by X-ray photoelectron spectroscopy and quantified by colorimetric methods. ECs were cultured to evaluate the cytocompatibility of surface-modified PCL NF and APCL NF. Gelatin grafting can obviously enhance EC spreading and proliferation compared with the original material. Moreover, gelatin-grafted APCL NF readily orients ECs along the fibers whereas unmodified APCL NF does not. Immunostaining micrographs showed that ECs cultured on gelatin-grafted PCL NF were able to maintain the expression of three characteristic markers: platelet-endothelial cell adhesion molecule 1 (PECAM-1), intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1). The surface-modified PCL nanofibrous material is a potential candidate material in blood vessel tissue engineering.

  10. A Zr-based bulk metallic glass for future stent applications: Materials properties, finite element modeling, and in vitro human vascular cell response.

    Science.gov (United States)

    Huang, Lu; Pu, Chao; Fisher, Richard K; Mountain, Deidra J H; Gao, Yanfei; Liaw, Peter K; Zhang, Wei; He, Wei

    2015-10-01

    Despite the prevalent use of crystalline alloys in current vascular stent technology, new biomaterials are being actively sought after to improve stent performance. In this study, we demonstrated the potential of a Zr-Al-Fe-Cu bulk metallic glass (BMG) to serve as a candidate stent material. The mechanical properties of the Zr-based BMG, determined under both static and cyclic loadings, were characterized by high strength, which would allow for the design of thinner stent struts to improve stent biocompatibility. Finite element analysis further complemented the experimental results and revealed that a stent made of the Zr-based BMG was more compliant with the beats of a blood vessel, compared with medical 316L stainless steel. The Zr-based BMG was found to be corrosion resistant in a simulated body environment, owing to the presence of a highly stable ZrO2-rich surface passive film. Application-specific biocompatibility studies were conducted using human aortic endothelial cells and smooth muscle cells. The Zr-Al-Fe-Cu BMG was found to support stronger adhesion and faster coverage of endothelial cells and slower growth of smooth muscle cells than 316L stainless steel. These results suggest that the Zr-based BMG could promote re-endothelialization and potentially lower the risk of restenosis, which are critical to improve vascular stent implantation integration. In general, findings in this study raised the curtain for the potential application of BMGs as future candidates for stent applications. Vascular stents are medical devices typically used to restore the lumen of narrowed or clogged blood vessel. Despite the clinical success of metallic materials in stent-assisted angioplasty, post-surgery complications persist due to the mechanical failures, corrosion, and in-stent restenosis of current stents. To overcome these hurdles, strategies including new designs and surface functionalization have been exercised. In addition, the development of new materials with

  11. Fatores de risco para acidente vascular encefálico após cirurgia de revascularização do miocárdio Risk factors for stroke after coronary artery bypass grafting

    Directory of Open Access Journals (Sweden)

    Dinaldo Cavalcanti de Oliveira

    2008-10-01

    Full Text Available FUNDAMENTO: O acidente vascular encefálico (AVE é uma temida complicação após cirurgia de revascularização do miocárdio (CRM, com incidência entre 1,3% e 4,3%. OBJETIVO: Identificar fatores preditores de AVE após CRM, na era moderna da cirurgia cardíaca. MÉTODOS: Este é um estudo caso-controle de 65 pares de pacientes, no qual o pareamento foi realizado por sexo, idade (+ 3 anos e data da CRM (+ 3 meses. Os casos são pacientes submetidos à CRM eletiva com circulação extracorpórea (CEC, que apresentaram AVE (definido como déficit clínico neurológico até 24 horas de pós-operatório e confirmado por exame de imagem, e os controles aqueles submetidos à CRM eletiva com CEC sem AVE. RESULTADOS: A análise univariada revelou que o número de vasos revascularizados foi associado com a ocorrência de AVE após a CRM (3 ± 0,8 vs. 2,76 ± 0,8, p = 0,01. Na análise multivariada por regressão logística condicional, a hipertensão arterial sistêmica [OR: 6,1 (1,5 - 24, p = 0,009] e o diabete melito [OR: 3,1 (1,09 - 11, p= 0,03] foram determinantes de maior chance de AVE após CRM, e o infarto agudo do miocárdio > 1 mês determinante de menor chance [OR: 0,1 (0,03 - 0,36, p = 0,003]. CONCLUSÃO: Hipertensão e diabete melito foram identificados como preditores independentes de AVE nas primeiras 24 horas de pós-operatório de CRM. Em pacientes com tais fatores de risco, é possível que o conhecimento dos mecanismos causadores da injúria cerebral represente uma estratégia capaz de diminuir a incidência de AVE após CRM.BACKGROUND: Stroke is a feared complication after coronary artery bypass grafting surgery (CABG, with an incidence between 1.3 and 4.3%. OBJECTIVE: To identify predictive factors for stroke after CABG in the modern era of cardiac surgery. METHODS: This is a case-control study of 65 pairs of patients, paired by sex, age (+ 3 years and date of CABG (+ 3 months. The cases were patients submitted to elective CABG

  12. Hemocompatibility of Chitosan/poly(acrylic acid) Grafted Polyurethane Tubing

    OpenAIRE

    Lee, Hyun-Su; Tomczyk, Nancy; Kandel, Judith; Composto, Russell J.; Eckmann, David M.

    2013-01-01

    The activation and adhesion of platelets or whole blood exposed to chitosan (CH) grafted surfaces is used to evaluate the hemocompatibility of biomaterials. The biomaterial surfaces are polyurethane (PU) tubes grafted with an inner poly(acrylic acid) (PAA) and an outer CH or quaternary ammonium modified CH (CH-Q) brush. The CH, CH-Q and PAA grafted layers were characterized by ellipsometry and fluorescence microscopy. Material wear tests demonstrate that CH (CH-Q) is stably grafted onto PU tu...

  13. [Experimental study of allogenic tendon with sheath grafting in chicken].

    Science.gov (United States)

    Zhang, Y L; Wang, S L; Gao, X S

    2001-03-01

    To investigate availability of deep freeze stored allogenic tendon with sheath grafting in repairing the tendon and sheath defect in the II area of flexor digitorum tendon. Sixty chickens with tendon and sheath defect were divided into 2 groups randomly, group A was treated with allogenic grafting and group B was treated with autogenic grafting, these two groups were divided into two subgroups respectively, they were, group A1 allogenic tendon with whole sheath grafting, group A2 allogenic tendon with partial sheath grafting, group B1 autogenic tendon with whole sheath grafting and group B2 autogenic tendon with whole sheath grafting. All the allogenic grafts were treated by deep freeze. Histomorphological study, histoimmunological study and slipping function of the grafts were measured after operation. In group A1 and B1, the local reaction was sever, the nutrition of tendon graft was barricaded by the whole sheath resulting in adhesion, degeneration and necrosis. In group A2 and B2, the tendon graft healed well and little adhesion existed between tendon and sheath. The results showed that there were significant differences between tendon grafting with whole sheath and tendon grafting with partial sheath. Deep freeze store can reduce the immunogenicity of allogenic tendon with sheath. Allogenic tendon with partial sheath grafting can be used as a new biological material for repairing the tendon and sheath defect.

  14. Utilization of arterial grafts in foot replantation

    Directory of Open Access Journals (Sweden)

    Selami S. Sirvan, MD

    2017-03-01

    Full Text Available Our subject is a 36-year-old man who presented to the emergency department with bilateral lower extremity amputation at the level of the distal third of the tibia after a car accident. Surgery was planned for below-knee amputation of the right lower extremity and replantation of the left foot. The arteries dissected from the iatrogenically amputated segment were used as grafts to repair vascular gaps during the replantation. The patient's follow-up had been problem free. We concluded that whenever possible, amputated parts unsuitable for replantation should be examined thoroughly and neurovascular structures that might be used as grafts should be preserved.

  15. Utilization of arterial grafts in foot replantation.

    Science.gov (United States)

    Sirvan, Selami S; Dagdelen, Daghan; Akgun Demir, Isil; Cezairlioglu, Mecd Atif; Sezer, Hasan Basri; Karsidag, Semra

    2017-03-01

    Our subject is a 36-year-old man who presented to the emergency department with bilateral lower extremity amputation at the level of the distal third of the tibia after a car accident. Surgery was planned for below-knee amputation of the right lower extremity and replantation of the left foot. The arteries dissected from the iatrogenically amputated segment were used as grafts to repair vascular gaps during the replantation. The patient's follow-up had been problem free. We concluded that whenever possible, amputated parts unsuitable for replantation should be examined thoroughly and neurovascular structures that might be used as grafts should be preserved.

  16. Silk biomaterials functionalized with recombinant domain V of human perlecan modulate endothelial cell and platelet interactions for vascular applications.

    Science.gov (United States)

    Rnjak-Kovacina, Jelena; Tang, Fengying; Whitelock, John M; Lord, Megan S

    2016-12-01

    Modulation of endothelial cell and platelet interactions is an essential feature of vascular materials. Silk biomaterials were functionalized with recombinantly expressed domain V of human perlecan, an essential vascular proteoglycan involved in vasculogenesis, angiogenesis and wound healing, using passive adsorption or covalent cross-linking via carbodiimide chemistry. The orientation of domain V on the surface of silk biomaterials was modulated by the immobilization technique and glycosaminoglycan chains played an essential role in the proteoglycan presentation on the material surface. Covalent immobilization supported improved integrin binding site presentation to endothelial cells compared to passive adsorption in the presence of glycosaminoglycan chains, but removal of glycosaminoglycan chains resulted in reduced integrin site availability and thus cell binding. Silk biomaterials covalently functionalized with domain V supported endothelial cell adhesion, spreading and proliferation and were anti-adhesive for platelets, making them promising surfaces for the development of the next-generation vascular grafts. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Evaluation of anorganic bovine-derived hydroxyapatite matrix/cell binding peptide as a bone graft material in the treatment of human periodontal infrabony defects: A clinico-radiographic study

    Directory of Open Access Journals (Sweden)

    Ghousia Fatima

    2015-01-01

    Full Text Available Background: Various bone graft materials have been used in the treatment of periodontal defects. A synthetic bone substitute material composed of P-15 with anorganic bone mineral has been scantly studied. Hence, the present study was aimed to evaluate and compare the efficacy of anorganic bovine-derived hydroxyapatite matrix (ABM/cell binding peptide (P-15 in human periodontal infrabony defects with that of open flap debridement (OFD alone. Materials and Methods: A split-mouth, randomized controlled clinical study was designed to investigate the efficacy of ABM/P-15. In this clinical trial, 10 patients having bilateral periodontal infrabony defects were treated either with ABM/P-15 or OFD and followed for a period of 9 months. At baseline and at 9 months probing pocket depth (PPD, relative attachment level (RAL, depth of a defect, and radiographic bone level were measured; and compared between test and control sites. Results: A statistically significant reduction (P < 0.001 in PPD was observed in test sites compared to control sites. Both sites showed a gain in RAL without any significant difference. Similarly, the radiographic evaluation revealed significantly higher radiographic defect fill in test sites as compared to control sites (P < 0.001. Conclusion: ABM/P-15 bone graft material appears to be useful and beneficial in the treatment of human periodontal infrabony defects.

  18. Standardized Definitions for Hemodialysis Vascular Access

    OpenAIRE

    Lee, Timmy; Mokrzycki, Michele; Moist, Louise; Maya, Ivan; Vazquez, Miguel; Lok, Charmaine

    2011-01-01

    Vascular access dysfunction is one of the leading causes of morbidity and mortality among end-stage renal disease patients 1,2. Vascular access dysfunction exists in all 3 types of available accesses: arteriovenous fistulas, arteriovenous grafts, and tunneled catheters. In order to improve clinical research and outcomes in hemodialysis access dysfunction, the development of a multidisciplinary network of collaborative investigators with various areas of expertise, and common standards for ter...

  19. Development and Assessment of a 3D-Printed Scaffold with rhBMP-2 for an Implant Surgical Guide Stent and Bone Graft Material: A Pilot Animal Study

    Directory of Open Access Journals (Sweden)

    Ji Cheol Bae

    2017-12-01

    Full Text Available In this study, a new concept of a 3D-printed scaffold was introduced for the accurate placement of an implant and the application of a recombinant human bone morphogenetic protein-2 (rhBMP-2-loaded bone graft. This preliminary study was conducted using two adult beagles to evaluate the 3D-printed polycaprolactone (PCL/β-tricalcium phosphate (β-TCP/bone decellularized extracellular matrix (bdECM scaffold conjugated with rhBMP-2 for the simultaneous use as an implant surgical guide stent and bone graft material that promotes new bone growth. Teeth were extracted from the mandible of the beagle model and scanned by computed tomography (CT to fabricate a customized scaffold that would fit the bone defect. After positioning the implant guide scaffold, the implant was placed and rhBMP-2 was injected into the scaffold of the experimental group. The two beagles were sacrificed after three months. The specimen block was obtained and scanned by micro-CT. Histological analysis showed that the control and experimental groups had similar new bone volume (NBV, % but the experimental group with BMP exhibited a significantly higher bone-to-implant contact ratio (BIC, %. Within the limitations of this preliminary study, a 3D-printed scaffold conjugated with rhBMP-2 can be used simultaneously as an implant surgical guide and a bone graft in a large bone defect site. Further large-scale studies will be needed to confirm these results.

  20. Xenopericardial roll graft replacement for infectious pseudoaneurysms and graft infections of the aorta.

    Science.gov (United States)

    Kubota, Hiroshi; Endo, Hidehito; Noma, Mio; Ishii, Hikaru; Tsuchiya, Hiroshi; Yoshimoto, Akihiro; Takahashi, Yu; Inaba, Yusuke; Nishino, Yoshifumi; Nunokawa, Masao; Hosoi, Yutaka; Ikezoe, Tooru; Nemoto, Masaru; Makino, Yoshihisa; Nemoto, Yoko; Matsukura, Mitsuru; Sugiyama, Masanori; Abe, Nobutsugu; Takeuchi, Hirohisa; Nagao, Gen; Kondo, Eri; Yanagida, Osamu; Yoshino, Hideaki; Sudo, Kenichi

    2015-10-27

    Which graft material is the optimal graft material for the treatment of infected aortic aneurysms and aortic graft infections is still a matter of controversy. Orthotopic aortic reconstruction with intraoperatively prepared xenopericardial roll grafts without omentopexy was performed as the "initial" operation to treat aortic infection or as a "rescue" operation to treat graft infection. Mid-term outcomes were evaluated. Between 2009 and 2013, orthotopic xenopericardial roll graft replacement was performed to treat eight patients (male/female: 6/2; mean age: 69.5 [55-80] yr). Graft material: equine/bovine pericardium: 2/6; type of operation: initial 4/rescue 4; omentopexy 0. Additional operation: esophagectomy 2. Mean follow-up period: 2.6 ± 1.6 (1.1-5.1) years. Replacement: ascending 3, arch 1 (reconstruction of neck vessels with small xenopericardial roll grafts), descending 3, and thoracoabdominal 1. Pathogens: MRSA 2, MSSA 1, Candida 1, E. coli 1, oral bacillus 1, and culture negative 2. Postoperative local recurrence of infection: 0. Graft-related complications: stenosis 0, calcification 0, non-infectious pseudoaneurysm of anastomosis 2 (surgical repair: 1/TEVAR 1). In-hospital mortality: 2 (MOF: initial 1/rescue 1); Survival rate exclusive of in-hospital deaths (~3 y): 100 %, but one patient died of lung cancer (3.6 yr). Because xenopericardial roll grafts are not composed of synthetic material, the replacement procedure is simpler and less invasive than the standard procedure. Based on the favorable results obtained, this procedure may have the possibility to serve as an option for the treatment of aortic infections and aortic graft infections not only as a "rescue" treatment but as an "initial" treatment as well.

  1. [Vascular dementia

    NARCIS (Netherlands)

    Leeuw, H.F. de; Gijn, J. van

    2004-01-01

    Vascular dementia is one of the most frequently occurring dementia syndromes. Its prevalence is about 5% among subjects above 85 years of age. Elevated blood pressure and atherosclerosis are the most important risk factors. According to international criteria, vascular dementia usually occurs within

  2. Histomorhological and clinical evaluation of maxillary alveolar ridge reconstruction after craniofacial trauma by applying combination of allogeneic and autogenous bone graft

    Directory of Open Access Journals (Sweden)

    Francesco Saverio De Ponte

    2017-02-01

    Full Text Available A variety of techniques and materials for the rehabilitation and reconstruction of traumatized maxillary ridges prior to dental implants placement have been described in literature. Autogenous bone grafting is considered ideal by many researchers and it still remains the most predictable and documented method. The aim of this report is to underline the effectiveness of using allogeneic bone graft for managing maxillofacial trauma. A case of a 30-year-old male with severely atrophic maxillary ridge as a consequence of complex craniofacial injury is presented here. Augmentation procedure in two stages was performed using allogeneic and autogenous bone grafts in different areas of the osseous defect. Four months after grafting, during the implants placement surgery, samples of both sectors were withdrawn and submitted to histological evaluation. On the examination of the specimens, treated by hematoxylin and eosin staining, the morphology of integrated allogeneic bone grafts was revealed to be similar to the autologous bone. Our clinical experience shows how the allogeneic bone graft presented normal bone tissue architecture and is highly vascularized, and it can be used for reconstruction of severe trauma of the maxilla.

  3. Histomorhological and clinical evaluation of maxillary alveolar ridge reconstruction after craniofacial trauma by applying combination of allogeneic and autogenous bone graft.

    Science.gov (United States)

    De Ponte, Francesco Saverio; Falzea, Roberto; Runci, Michele; Siniscalchi, Enrico Nastro; Lauritano, Floriana; Bramanti, Ennio; Cervino, Gabriele; Cicciu, Marco

    2017-02-01

    A variety of techniques and materials for the rehabilitation and reconstruction of traumatized maxillary ridges prior to dental implants placement have been described in literature. Autogenous bone grafting is considered ideal by many researchers and it still remains the most predictable and documented method. The aim of this report is to underline the effectiveness of using allogeneic bone graft for managing maxillofacial trauma. A case of a 30-year-old male with severely atrophic maxillary ridge as a consequence of complex craniofacial injury is presented here. Augmentation procedure in two stages was performed using allogeneic and autogenous bone grafts in different areas of the osseous defect. Four months after grafting, during the implants placement surgery, samples of both sectors were withdrawn and submitted to histological evaluation. On the examination of the specimens, treated by hematoxylin and eosin staining, the morphology of integrated allogeneic bone grafts was revealed to be similar to the autologous bone. Our clinical experience shows how the allogeneic bone graft presented normal bone tissue architecture and is highly vascularized, and it can be used for reconstruction of severe trauma of the maxilla. Copyright © 2017 Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. Production and hosting by Elsevier B.V. All rights reserved.

  4. Evaluation of anorganic bovine-derived hydroxyapatite matrix/cell binding peptide as a bone graft material in the treatment of human periodontal infrabony defects: A clinico-radiographic study.

    Science.gov (United States)

    Fatima, Ghousia; Shivamurthy, Ravindra; Thakur, Srinath; Baseer, Mohammad Abdul

    2015-01-01

    Various bone graft materials have been used in the treatment of periodontal defects. A synthetic bone substitute material composed of P-15 with anorganic bone mineral has been scantly studied. Hence, the present study was aimed to evaluate and compare the efficacy of anorganic bovine-derived hydroxyapatite matrix (ABM)/cell binding peptide (P-15) in human periodontal infrabony defects with that of open flap debridement (OFD) alone. A split-mouth, randomized controlled clinical study was designed to investigate the efficacy of ABM/P-15. In this clinical trial, 10 patients having bilateral periodontal infrabony defects were treated either with ABM/P-15 or OFD and followed for a period of 9 months. At baseline and at 9 months probing pocket depth (PPD), relative attachment level (RAL), depth of a defect, and radiographic bone level were measured; and compared between test and control sites. A statistically significant reduction (P bone graft material appears to be useful and beneficial in the treatment of human periodontal infrabony defects.

  5. Vascular injuries during gynecological laparoscopy: the vascular surgeon's advice

    Directory of Open Access Journals (Sweden)

    Marcello Barbosa Barros

    Full Text Available CONTEXT: Iatrogenic vascular problems due to laparoscopy are a well recognized problem and lead to significant repercussions. In this context, a ten-year review of cases topic is presented, based on experience gained while heading two important vascular surgery services. CASES: Five patients with vascular injuries during elective laparoscopy are described. These patients presented with seven lesions of iliac vessels. All cases were evaluated immediately and required laparotomy, provisional hemostasis and urgent attendance by a vascular surgeon. Direct suturing was performed in three cases. One aortoiliac bypass and one ilioiliac reversed venous graft were made. Venous lesions were sutured. One case of a point-like perforation of the small bowel was found. There were no deaths and no complications during the postoperative period. DISCUSSION: Important points on this subject are made, and advice is given. There needs to be immediate recognition of the vascular injury, and expert repair by a vascular surgeon is recommended, in order to significantly reduce the degree of complications.

  6. Bone grafts in dentistry

    Directory of Open Access Journals (Sweden)

    Prasanna Kumar

    2013-01-01

    Full Text Available Bone grafts are used as a filler and scaffold to facilitate bone formation and promote wound healing. These grafts are bioresorbable and have no antigen-antibody reaction. These bone grafts act as a mineral reservoir which induces new bone formation.

  7. Vascular ring

    DEFF Research Database (Denmark)

    Schmidt, Anne Mette S; Larsen, Signe H; Hjortdal, Vibeke E

    2018-01-01

    BACKGROUND: Vascular ring is a rare cause of recurrent respiratory infections, dysphagia and stridor. Surgical repair is considered safe but the long-term outcomes are unclear. The purpose of this study was to investigate the mortality and morbidity following vascular ring surgery in a single...... age of 1.4 years (range 0.008-64 years) were operated for vascular ring. Median follow-up was 6.8 years (range 2.4-34 years). Presenting symptoms were stridor (52%), dysphagia or vomiting (52%) and recurrent respiratory infections (48%). There were no early or late deaths. Three months postoperatively...

  8. Reconstruction of lower end of radius using vascularized upper end of fibula

    Directory of Open Access Journals (Sweden)

    Koul Ashok

    2007-01-01

    Full Text Available Background: Giant cell tumor is a fairly common locally invasive tumor in young adults. The lower end of the radius is the second commonest site for this tumor. The most common treatment for this tumor is curettage with or without bone grafting but it carries a significant rate of recurrence. Excision is the treatment of choice, especially for cases in which the cortex has been breached. After excision of the distal end of the radius, different procedures have been described to reconstruct the defect of distal radius. These include partial arthrodesis and hemiarthroplasty using the upper end of the fibula. The upper end of the fibula has a morphological resemblance to the lower end of the radius and has been used to replace the latter. Traditionally it was used as a ′free′ (non-vascularized graft. More recently the upper end of the fibula has been transferred as a vascularized transfer for the same purpose. Though vascularized transfer should be expected to be more physiological, its superiority over the technically simpler non-vascularized transfer has not been conclusively proven. Materials and Methods: Two patients are presented who had giant cell tumor of distal radius. They underwent wide local excision and reconstruction with free vascularized upper end of the fibula. Result: Follow-up period was two and a half years and 12 months respectively. Both patients have returned to routine work. One patient has excellent functional result and the other has a good result. Conclusion: Vascularized upper end of fibula transfer is a reliable method of reconstruction for loss of the distal end of the radius that restores local anatomy and physiology.

  9. Reconstruction of the bulbar urethra using dorsal onlay buccal mucosal grafts: New concepts and surgical tricks

    Directory of Open Access Journals (Sweden)

    Guido Barbagli

    2006-01-01

    Full Text Available Buccal mucosa onlay graft urethroplasty represents one of the most widespread methods for the repair of strictures in the bulbar urethra, because of its thick and highly vascular spongiosum tissue. Recently the location of the patch has become a contentious issue, since we described our original techniques of dorsal onlay graft urethroplasty. The design rationale for this approach was based on the concept that the corporeal body remains a healthy host for receiving a free transplanted tissues. Moreover, graft fixation onto a defined surface may decrease graft shrinkage and sacculation. The success rate using buccal mucosa grafts for the repair of bulbar urethral strictures has generally been high with dorsal or ventral onlay grafts or using an augmented roof-strip anastomotic urethroplasty. We describe here the fundamental concepts of the bulbar urethra reconstruction using buccal mucosal grafts, presenting a new surgical technique of dorsal onlay buccal mucosa graft urethroplasty using fibrin glue.

  10. VASCULAR SURGERY

    African Journals Online (AJOL)

    2016-06-02

    Jun 2, 2016 ... Aortic arch injuries. (2) were repaired operatively with cardiopulmonary bypass, descending aortic injuries (2) were treated by stent graft, and common carotid (1) and subclavian artery injuries (2) were treated by open repair at the quaternary centre. Of the 20 venous injuries that were managed operatively,.

  11. Vascular anomalies

    Directory of Open Access Journals (Sweden)

    Murthy Jyotsna

    2005-01-01

    Full Text Available Management of vascular anomalies is an emerging multidisciplinary, super-specialisation field involving several surgical, medical and radiological specialties. Over the years, development in this field has been limited because of complex nomenclature and lack of consensus on the best practice for treatment of some of the more complex vascular anomalies. It was only in 1996 that the International Society of the Study of Vascular Anomalies defined nomenclature for the anomalies and gave clear guidelines on management, allowing for improved clinical practices. As in all fields of clinical medicine, the correct diagnosis of the vascular anomalies is essential to choose the appropriate treatment. This paper gives clear guidelines for diagnosis, understanding of the anomalies and discusses their management.

  12. Corneal Graft Rejection: Incidence and Risk Factors

    Directory of Open Access Journals (Sweden)

    Alireza Baradaran-Rafii

    2008-12-01

    Full Text Available

    PURPOSE: To determine the incidence and risk factors of late corneal graft rejection after penetrating keratoplasty (PKP. METHODS: Records of all patients who had undergone PKP from 2002 to 2004 without immunosuppressive therapy other than systemic steroids and with at least one year of follow up were reviewed. The role of possible risk factors such as demographic factors, other host factors, donor factors, indications for PKP as well as type of rejection were evaluated. RESULTS: During the study period, 295 PKPs were performed on 286 patients (176 male, 110 female. Mean age at the time of keratoplasty was 38±20 (range, 40 days to 90 years and mean follow up period was 20±10 (range 12-43 months. Graft rejection occurred in 94 eyes (31.8% at an average of 7.3±6 months (range, 20 days to 39 months after PKP. The most common type of rejection was endothelial (20.7%. Corneal vascularization, regrafting, anterior synechiae, irritating sutures, active inflammation, additional anterior segment procedures, history of trauma, uncontrolled glaucoma, prior graft rejection, recurrence of herpetic infection and eccentric grafting increased the rate of rejection. Patient age, donor size and bilateral transplantation had no significant influence on graft rejection. CONCLUSION: Significant risk factors for corneal graft rejection include

  13. Vascular Dementia

    OpenAIRE

    Maria Alekseyevna Cherdak; O V Uspenskaya

    2015-01-01

    This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/S0140-6736(15)00463-8 Vascular dementia is one of the most common causes of dementia after Alzheimer's disease, causing around 15% of cases. However, unlike Alzheimer's disease, there are no licensed treatments for vascular dementia. Progress in the specialty has been difficult because of uncertainties over disease classification and diagnostic criteria, controversy over the e...

  14. Cytocompatibility of amine functionalized carbon nanoparticles grafted on polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Žáková, Pavlína, E-mail: pavlina.zakova@vscht.cz [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic); Slepičková Kasálková, Nikola [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic); Kolská, Zdeňka [Faculty of Science, J. E. Purkyně University, Ústí nad Labem (Czech Republic); Leitner, Jindřich [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic); Karpíšková, Jana; Stibor, Ivan [Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec (Czech Republic); Slepička, Petr; Švorčík, Václav [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic)

    2016-03-01

    Five types of amide–amine Carbon Nano-Particles (CNPs) were prepared by functionalization of CNPs and characterized by several analytical methods. The successful grafting of amines on CNPs was verified by X-ray photoelectron spectroscopy (XPS), organic elemental analysis and electrokinetic analysis. The size and morphology of CNPs were determined from transmission electron microscopy. The surface area and porosity of CNPs were examined by adsorption and desorption isotherms. Differential scanning calorimetry was used to investigate thermal stability of CNPs. The amount of bonded amine depends on its dimensionality arrangement. Surface area and pore volumes of CNPs decrease several times after individual amino-compound grafting. Selected types of functionalized CNPs were grafted onto a plasma activated surface of HDPE. The successful grafting of CNPs on the polymer surface was verified by XPS. Wettability was determined by contact angle measurements. Surface morphology and roughness were studied by atomic force microscopy. A dramatic decrease of contact angle and surface morphology was observed on CNP grafted polymer surface. Cytocompatibility of modified surfaces was studied in vitro, by determination of adhesion, proliferation and viability of vascular smooth muscle cells (VSMCs). Grafting of CNPs onto the polymer surface has a positive effect on the adhesion, proliferation and viability of VSMCs. - Highlights: • Amine functionalized CNPs were successfully grafted on HDPE surface. • Significant change to the positive zeta potential for grafted CNPs was induced. • Grafting of CNPs significantly enhanced cell cytocompatibility and viability. • Homogeneous distribution of cells with correct size was achieved.

  15. Vascular Vertigo

    Directory of Open Access Journals (Sweden)

    Mazyar Hashemilar

    2017-02-01

    Full Text Available Vertigo is a common complaint in neurology and medicine. The most common causes of vertigo are benign paroxysmal positional vertigo, vestibular neuritis, Meniere’s disease, and vascular disorders. Vertigo of vascular origin is usually limited to migraine, transient ischemic attacks, and ischemic or hemorrhagic stroke. Vascular causes lead to various central or peripheral vestibular syndromes with vertigo. This review provides an overview of epidemiology and clinical syndromes of vascular vertigo. Vertigo is an illusion of movement caused by asymmetrical involvement of the vestibular system by various causes. Migraine is the most frequent vascular disorder that causes vertigo in all age groups. Vertigo may occur in up to 25% of patients with migraine. The lifetime prevalence of migrainous vertigo is almost 1%. Cerebrovascular disorders are estimated to account for 3% to 7% of patients with vertigo. Vestibular paroxysmia has been diagnosed in 1.8% to 4% of cases in various dizziness units. Vasculitic disorders are rare in the general population, but vertigo may be seen in almost up to 50% of patients with different vasculitic syndromes. Conclusions: Migraine, cerebrovascular disorders especially involving the vertebrobasilar territory, cardiocirculatory diseases, neurovascular compression of the eighth nerve, and vasculitis are vascular causes of vertigo syndromes.

  16. [Bladder injury by penetration of artificial vessel graft].

    Science.gov (United States)

    Wada, Naoki; Tamaki, Gaku; Kura, Tatsuhiko; Saga, Yuji; Kakizaki, Hidehiro

    2009-01-01

    Iatrogenic bladder injury by artificial vessel graft is extremely rare and only 3 cases have been reported. Herein, we report a case of bladder injury by penetration of artificial vessel graft. An 80-year-old male underwent a femoro-femoral crossover bypass surgery for arteriosclerosis obliterans in our hospital. Postoperatively he complained of urinary incontinence and was referred to the urology department. Ultrasonography for evaluating microscopic hematuria revealed a high echoic linear structure in the bladder and subsequent cystoscopy found an artificial vessel graft penetrating bladder wall. Vascular surgeons reconstructed femoro-femoral bypass and we removed the artificial vessel graft and repaired the injured bladder wall. This is the fourth case of bladder penetrating injury by artificial vessel graft and we summarize the reported cases.

  17. Matrix metalloproteinase inhibition reduces intimal hyperplasia in a porcine arteriovenous-graft model.

    NARCIS (Netherlands)

    Rotmans, J.I.; Velema, E.; Verhagen, H.J.; Blankensteijn, J.D.; Kleijn, D.P. de; Stroes, E.S.; Pasterkamp, G.

    2004-01-01

    BACKGROUND: The patency of arteriovenous (AV) polytetrafluoroethylene grafts for hemodialysis is impaired by intimal hyperplasia (IH) at the venous outflow tract. IH mainly consists of vascular smooth muscle cells, fibroblasts, and extracellular matrix proteins. Because matrix metalloproteinases

  18. Matrix metalloproteinase inhibition reduces intimal hyperplasia in a porcine arteriovenous-graft model

    NARCIS (Netherlands)

    Rotmans, JI; Velema, E; Verhagen, HJM; Blankensteijn, JD; de Kleijn, DPV; Stroes, ESG; Pasterkamp, G

    Background: The patency of arteriovenous (AV) polytetrafluoroethylene grafts for hemodialysis is impaired by intimal hyperplasia (IH) at the venous outflow tract. IH mainly consists of vascular smooth muscle cells, fibroblasts, and extracellular matrix proteins. Because matrix metalloproteinases

  19. Influence of physico-chemical material characteristics on staphylococcal biofilm formation--a qualitative and quantitative in vitro analysis of five different calcium phosphate bone grafts.

    Science.gov (United States)

    Clauss, M; Furustrand Tafin, U; Betrisey, B; van Garderen, N; Trampuz, A; Ilchmann, T; Bohner, M

    2014-07-18

    Various compositions of synthetic calcium phosphates (CaP) have been proposed and their use has considerably increased over the past decades. Besides differences in physico-chemical properties, resorption and osseointegration, artificial CaP bone graft might differ in their resistance against biofilm formation. We investigated standardised cylinders of 5 different CaP bone grafts (cyclOS, chronOS (both β-TCP (tricalcium phosphate)), dicalcium phosphate (DCP), calcium-deficient hydroxyapatite (CDHA) and α-TCP). Various physico-chemical characterisations e.g., geometrical density, porosity, and specific surface area were investigated. Biofilm formation was carried out in tryptic soy broth (TSB) and human serum (SE) using Staphylococcus aureus (ATCC 29213) and S. epidermidis RP62A (ATCC 35984). The amount of biofilm was analysed by an established protocol using sonication and microcalorimetry. Physico-chemical characterisation showed marked differences concerning macro- and micropore size, specific surface area and porosity accessible to bacteria between the 5 scaffolds. Biofilm formation was found on all scaffolds and was comparable for α-TCP, chronOS, CDHA and DCP at corresponding time points when the scaffolds were incubated with the same germ and/or growth media, but much lower for cyclOS. This is peculiar because cyclOS had an intermediate porosity, mean pore size, specific surface area, and porosity accessible to bacteria. Our results suggest that biofilm formation is not influenced by a single physico-chemical parameter alone but is a multi-step process influenced by several factors in parallel. Transfer from in vitro data to clinical situations is difficult; thus, advocating the use of cyclOS scaffolds over the four other CaP bone grafts in clinical situations with a high risk of infection cannot be clearly supported based on our data.

  20. Thumb proximal phalanx reconstruction with nonvascularized corticocancellous olecranon bone graft.

    Science.gov (United States)

    Soong, Maximillian

    2015-01-01

    Large segmental bone defects of the phalanges reportedly have been treated with free vascularized grafts from the hand, foot, or knee, or with nonvascularized grafts from the iliac crest. A nonvascularized structural corticocancellous graft from a local site would be advantageous. The olecranon has been used as a source of both cancellous and corticocancellous graft. The authors describe a unique case of the use of nonvascularized corticocancellous olecranon bone graft for structural purposes in a mutilating thumb injury. The patient injured the left thumb with a miter saw, resulting in a large degloving wound over a severely comminuted fracture of the proximal phalanx, with segmental bone loss between a base fragment and displaced condylar fragments. Provisional pin fixation was performed at the time of initial emergent irrigation and debridement, along with repairs of the extensor pollicis longus, radial digital nerve, and dorsal digital nerve. This was followed 3 weeks later by non-vascularized corticocancellous bone grafting from the olecranon to the proximal phalanx under regional anesthesia. The thumb was mobilized at 11 weeks, and solid union was radiographically confirmed at 6 months. The patient achieved moderate active range of motion and was able to return to work as a physical therapist. The elbow healed uneventfully and without pain or fracture at the donor site. This case shows that robust structural bone graft for the phalanges may be obtained from the nearby olecranon, under regional anesthesia, without microsurgery, and with potential advantages over the iliac crest. Copyright 2015, SLACK Incorporated.

  1. Vascular Access Procedures

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Vascular Access Procedures A vascular access procedure inserts a flexible, ... the limitations of Vascular Access Procedures? What are Vascular Access Procedures? A vascular access procedure involves the insertion ...

  2. Vascular Access for Hemodialysis

    Science.gov (United States)

    ... Adequacy Eating & Nutrition for Hemodialysis Vascular Access for Hemodialysis What is a vascular access? A vascular access ... Set Up the Vascular Access Well before Starting Hemodialysis Patients should set up a vascular access well ...

  3. What Is Vascular Disease?

    Science.gov (United States)

    ... Policy What Is Vascular Disease? What Is Vascular Disease? Vascular disease is any abnormal condition of the blood ... Privacy Policy × Your ticket for the: What Is Vascular Disease? Title What Is Vascular Disease? USD Close Print

  4. Strontium doping of bone graft extender

    Science.gov (United States)

    2011-01-01

    Background and purpose Allografts are often used during revision hip replacement surgery for stabilization of the implant. Resorption of the allograft may exceed new bone formation, and instability of the prosthesis can develop. We investigated whether strontium could regulate the imbalance of fast resorption of allograft and slower formation of new bone, because it is both an anabolic and an anticatabolic agent. Method Strontium was added to the implant interface environment by doping a hydroxyapatite bone graft extender. 10 dogs each received 2 experimental titanium implants. The implants were inserted within a 2.7-mm concentric gap in cancellous bone. The gap was filled with 50% (v/v) allograft mixed with 50% bone graft extender. The extender either had 5% strontium doping (SrHA) or was undoped (HA). After 4 weeks, osseointegration and mechanical fixation were evaluated by histomorphometry and by push-out test. Results SrHA bone graft extender induced a 1.2-fold increase in volume of new bone, a 1.2-fold increase in allograft remaining in the gap, and a 1.4-fold increase in surface area of the bone graft extender material in contact with new bone compared to HA bone graft extender. All these increases were statistically significant. SrHA bone graft extender did not significantly improve ongrowth of bone onto the implants or improve any of the mechanical push-out parameters compared to HA bone graft extender. Interpretation Doping of the HA bone graft extender with 5% strontium increased gap healing, preserved more of the allograft in the gap, and increased the ongrowth of bone onto the bone graft extender material, but did not improve mechanical fixation. PMID:21895497

  5. The effect of plant growth regulators on apple graft union flexural strength and flexibility

    Science.gov (United States)

    The apple rootstock ‘Geneva® 41’ (‘G.41’) forms weak graft unions with multiple scions. Exogenous plant growth regulators (PGR) can influence vascular differentiation and wood formation, and thus may improve graft union strength. A series of commercial and experimental PGR formulations were applied ...

  6. Long-term internal thoracic artery bypass graft patency and geometry assessed by multidetector computed tomography

    DEFF Research Database (Denmark)

    Zacho, Mette; Lilleoer, Nikolaj Thomas; Kelbaek, Henning

    2012-01-01

    The left internal thoracic artery (LITA) undergoes vascular remodelling when used for coronary artery bypass grafting. In this study we tested the hypothesis that the extent of the LITA remodelling late after coronary artery bypass grafting assessed by multidetector computed tomography is related...

  7. Free fibular strut graft in neglected femoral neck fractures in adult

    Directory of Open Access Journals (Sweden)

    Azam Md Quamar

    2009-01-01

    Full Text Available Background: Neglected femoral neck fracture in adults still poses a formidable challenge. Existing treatment options varies from osteotomy (with or without graft to osteosynthesis using various implants and grafting techniques (muscle pedicle, vascularized, and nonvascularized fibula. The aim of this study was to assess outcome of nonvascularized fibular strut graft and cancellous screw fixation in neglected femoral neck fractures in the younger age group. Materials and Methods: Medical records of 32 patients of neglected femoral neck fracture, in the age group of 22-45 years (mean 37.8 years, operated between May 1994 to December 2001, were retrospectively reviewed. After the application of inclusion and exclusion criteria, 28 patients having three years minimum follow-up (mean 4.6 years were included. Delay between injury and operation varied from four weeks to 42 weeks (mean 16.4 weeks. Closed reduction was achieved in 17 patients; open reduction through Watson-Jones anterolateral approach was performed in the remaining 15 patients in whom closed reduction failed. The fracture was transfixed with three parallel guide wires. Appropriate sized cannulated lag screw (7 mm was then inserted in two of the wires. Selection of the third guide wire for fibula depended on the space available in both anteroposterior and lateral view. Results: Satisfactory bony union was obtained in 25 patients, of whom in four cases, the union occurred in 10-20° (mean 15° of varus. Nonunion occurred in three patients (9.37%, and aseptic necrosis occurred in another six patients (18.75%. Of the 25 patients where union was achieved, five patients showed excellent results; 14 good and six had poor functional result, as evaluated using modified Anglen criteria. Conclusion: Nonvascularized fibular strut graft along with cancellous screws provides a dependable and technically less-demanding alternative procedure for neglected femoral neck fractures in young adults. Fibula

  8. Exogenous modulation of TGF-{beta}{sub 1} influences TGF-{beta}R-III-associated vascularization during wound healing in irradiated tissue

    Energy Technology Data Exchange (ETDEWEB)

    Wehrhan, F.; Schultze-Mosgau, S. [University of Erlangen-Nuremberg (Germany). Department of Oral and Maxillofacial Surgery; Grabenbauer, G.G.; Roedel, F. [University of Erlangen-Nuremberg (Germany). Department of Radiation Oncology; Amann, K. [University of Erlangen-Nuremberg (Germany). Institute of Pathology

    2004-08-01

    Background and purpose: Following preoperative radiotherapy prior to ablative surgery of squamous epithelial cell carcinomas of the head and neck region, wound-healing disorders occur. Previous experimental studies showed altered expression of transforming growth factor-(TGF-){beta} isoforms following surgery in irradiated graft beds. Altered levels of TGF-{beta}{sub 1} are reported to promote fibrosis and to suppress vascularization during wound healing, whereas expression of TGF-{beta} receptor-III (TGF-{beta}R-III) is associated with vascularization. The aim of the study was to analyze the influence of anti-TGF-{beta}{sub 1} treatment on TGF-{beta}R-III-associated vascularization in the transition area between irradiated graft bed and graft. Material and methods: Wistar rats (male, weight 300-500 g) underwent preoperative irradiation of the head and neck region with 40 Gy (four fractions of 10 Gy each; n=16 animals). A free myocutaneous gracilis flap taken from the groin was then transplanted to the neck in all rats. The time interval between operation and transplantation was 4 weeks. Eight animals received 1 {mu}g anti-TGF-{beta}{sub 1} into the graft bed by intradermal injection on days 1-7 after surgery. On days 3, 7, 14, 28, 56, and 120, skin samples were taken from the transition area between transplant and graft bed and from the graft bed itself. Immunohistochemistry was performed using the ABC-POX method to analyze the TGF-{beta}R-III and E-selection expression. Histomorphometry was performed to analyze the percentage and the area of positively stained vessels. Results: A significantly higher expression of TGF-{beta}R-III was seen in the irradiated and anti-TGF-{beta}{sub 1}-treated graft bed in comparison to the group receiving preoperative irradiation followed by transplantation alone. The percentage of TGF-{beta}R-III positively staining capillaries from the total amount of capillaries in the anti-TGF-{beta}{sub 1}-treated graft bed was higher than in

  9. Vascular dementia.

    Science.gov (United States)

    O'Brien, John T; Thomas, Alan

    2015-10-24

    Vascular dementia is one of the most common causes of dementia after Alzheimer's disease, causing around 15% of cases. However, unlike Alzheimer's disease, there are no licensed treatments for vascular dementia. Progress in the specialty has been difficult because of uncertainties over disease classification and diagnostic criteria, controversy over the exact nature of the relation between cerebrovascular pathology and cognitive impairment, and the paucity of identifiable tractable treatment targets. Although there is an established relation between vascular and degenerative Alzheimer's pathology, the mechanistic link between the two has not yet been identified. This Series paper critiques some of the key areas and controversies, summarises treatment trials so far, and makes suggestions for what progress is needed to advance our understanding of pathogenesis and thus maximise opportunities for the search for new and effective management approaches. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. [Study on a novel vascular stent material (titanium oxide, Ti-O) coated with albumin and heparin: is it hemocompatible with fibrinogen].

    Science.gov (United States)

    Song, Jie; Wu, Xi; Huang, Nan; Xu, Biao; Jing, Fengjuan; Chen, Junying; Leng, Yongxiang; Yang, Ping; Wang, Jin; Sun, Hong; Zhao, Ansha

    2007-10-01

    The functional hemocompatibility between fibrinogen (FIG) and a novel vascular stent material (Ti-O film fixed with albumin and heparin) was investigated as follows: (1) Preparing the new biologic material (Ti-O) film; (2) Coating albumin and heparin on the Ti-O film; (3) Testing platelets (PL) adsorption; (4) Determining FIG adhesion number by use of enzyme linked immunoassay (ELISA); (5) Implanting the films from the test group of Ti-O film and from the comparison group of stainless steel (SS) film into the left and right femoral arteries respectively in 4 dogs. It was proved that albumin and heparin were fixed on Ti-O film. After 6 months, the femoral arteries of the dogs were resected. In the test group of Ti-O film coated with albumin and heparin, few PL adhered to the coat, their form did not change, and no thrombus was found by scanning electron microscopy; the result was better than that of plain Ti-O film, and was much better than that of SS film. Ti-O maintained normal transformation condition of FIG, and no C terminal of gamma chain in FIG was revealed. As it is known whether the hemocompatibility of a biomaterial is good depends upon its adsorption of FIG, and Ti-O has excellent reaction on albumin and heparin by chemical processes. In this study, the Ti-O film coated with albumin and heparin further reduced the absorption of FIG and PL when compared against the plain Ti-O film. So the Ti-O film coated with albumin and heparin has the insistent and permanent anticoagulant character.

  11. Injerto libre braquial medial Free medial arm graft

    Directory of Open Access Journals (Sweden)

    P. Martos Díaz

    2007-12-01

    Full Text Available Introducción. Entre las reconstrucciones de defectos titulares de cabeza y cuello, el injerto libre microvascularizado braquial medial no ha adquirido mucha popularidad debido a las variaciones anatómicas que se reflejan en la vascularización de éste. Nuestro objetivo es realizar una descripción de la anatomía y técnica quirúrgica, así como una revisión de la literatura describiendo las ventajas y desventajas de este tipo de injerto. Material y método. Presentamos el caso de una paciente con carcinoma epidermoide de mucosa yugal izquierda con afectación ganglionar ipsilateral. Se procedió a su resección con márgenes más disección cervical funcional. La reconstrucción del defecto se llevó a cabo mediante un injerto libre microvascularizado braquial medial de brazo izquierdo. Discusión. Pensamos que el injerto libre braquial medial de brazo se trata de una opción más segura a la hora de la reconstrucción de defectos cervicofaciales, aportando una serie de ventajas entre las que destacan: no sacrificio de una arteria terminal, cierre primario de la zona donante, mínimo defecto estético, y poseer una piel fina, elástica y sin vello.Introduction. Free medial microvascularized arm grafts have not become very popular for the reconstruction of head and neck defects due to anatomic variations in their vascularization. Our objective was to describe the anatomy and surgical technique and to review the literature on the advantages and disadvantages of free medial arm grafts. Material and methods. We report the case of a patient with squamous cell carcinoma of the left jugal mucosa with same-side lymph node involvement. The tumor was resected with margins and a functional cervical dissection was performed. The defect was reconstructed using a free medial microvascularized graft from the left arm. Discussion. We believe that free medial arm grafts are a safer option for the reconstruction of cervicofacial defects and that they offer

  12. Pediatric vascularized composite allotransplantation.

    Science.gov (United States)

    Doumit, Gaby; Gharb, Bahar Bassiri; Rampazzo, Antonio; Papay, Francis; Siemionow, Maria Z; Zins, James E

    2014-10-01

    Vascularized composite allotransplantation (VCA) has experienced a growing acceptance, which has led to a debate centered on extending the indications of the procedure to include pediatric patients. The aim of this article was to discuss such indications based on the evidence in pediatric solid organ transplantation, reconstructive surgery in children, and VCA in adult patients. Papers published on the outcomes of pediatric solid organ transplantation, growth after replantation of extremities, vascularized autologous tissue transfer, craniofacial surgery, orthognathic procedures, facial fractures, and outcomes after repair of peripheral nerves in children were reviewed. Although the outcomes of solid organ transplantation in children have improved, the transplanted organs continue to have a limited lifespan. Long-term immunosuppressive therapy exposes the patients to an increased lifetime risk of infections, diabetes, hypertension, dyslipidemia, cardiovascular disease, and malignancy. Growth impairment and learning disabilities are other relevant drawbacks, which affect the pediatric recipients. Nonadherence to medication is a common cause of graft dysfunction and loss among the adolescent transplant recipients. Rejection episodes, hospitalizations, and medication adverse effects contribute negatively to the quality of life of the patients. Although normal growth after limb transplantation could be expected, pediatric facial transplant recipients may present with arrest of growth of transplanted midfacial skeleton. Considering the non-life-threatening nature of the conditions that lead to eligibility for VCA, it is suggested that it is premature to extend the indications of VCA to include pediatric patients under the currently available immunosuppressive protocols.

  13. A Comparative Examination of the Clinical Outcome and Histological Appearance of Cryopreserved and Fresh Split-Thickness Skin Grafts.

    Science.gov (United States)

    Holzer, Paul W; Leonard, David A; Shanmugarajah, Kumaran; Moulton, Krysta N; Ng, Zhi Yang; Cetrulo, Curtis L; Sachs, David H

    The clinical use of frozen, human allogeneic skin grafts is considered a suitable alternative to freshly harvested allogeneic skin grafts when the latter are not available. However, limited functional and histological information exists regarding the effects of cryopreservation on allogeneic skin grafts, especially those across mismatched histocompatibility barriers. Thus, we performed a side-by-side comparative study of fresh vs frozen skin grafts, across both minor and major histocompatibility barriers, in a miniature swine model. Since porcine skin shares many physical and immunological properties with human skin, our findings have relevance to current clinical practices involving allogeneic grafting and may support future, temporary wound therapies involving frozen xenografts, comprised genetically modified porcine skin. Four miniature swine underwent harvest and grafting of split-thickness skin, with and without cryopreservation, in order to observe autologous grafts and grafts across minor and major histocompatibility barriers. A biopsy of the grafts was done at regular intervals for study of architecture, vascularization, and outcomes. All grafts vascularized without technical complications. Differences were noted in the early appearance of some fresh vs frozen grafts, but no significant difference was observed in overall survival times in any of the experimental groups. These results demonstrate that despite early observable differences in the healing process, cryopreservation and thawing does not significantly affect long-term graft survival or time to rejection, thus supporting the clinical and experimental use of fresh and frozen split-thickness skin grafts as comparable and interchangeable.

  14. Experimental interfascicular nerve grafting.

    Science.gov (United States)

    Bratton, B R; Kline, D G; Coleman, W; Hudson, A R

    1979-09-01

    Twenty-nine adult rhesus monkeys underwent complete laceration of both tibial nerves at mid-thigh level and repair by different methods to study the relative efficacy of autogenous interfascicular nerve grafts. Sixteen animals in Group I had an interfascicular graft repair using short sural nerve autografts on one limb and fascicular repair without grafts on the other limb. Thirteen animals in Group II, after having a 1-cm segment of tibial nerve resected, had an interfascicular graft repair without tension in one limb and an epineurial repair under moderate tension in the other limb. Evoked nerve and muscle action potentials and muscle strenght in response to repetitive and tetanic stimulation were recorded as baseline values prelaceration and then on re-exploration at 4, 6, 9, or 12 months. All nerves were examined by light and electron microscopy. Electrophysiological data, particularly muscle strength response, showed non-graft repairs to be superior at 4 and 6 months of regeneration. However, by 9 and 12 months the graft repairs had caught up and were equal to the non-graft repairs. Histologically, it was observed that many axons missed the graft segments and were present in extrafascicular connective tissues. Nonetheless, enough axons regenerated to the distal nerve to explain the success of these relatively short grafts. From the results of these experiments, it is concluded that use of autogenous interfascicular grafts offers no advantage over end-to-end non-graft repair. When and end-to-end repair cannot be achieved, use of short interfascicular nerve grafts is feasible and will work.

  15. Pancreatic transplantation: Radiologic evaluation of vascular complications

    Energy Technology Data Exchange (ETDEWEB)

    Snider, J.F.; Hunter, D.W.; Kuni, C.C.; Castaneda-Zuniga, W.R.; Letourneau, J.G. (Univ. of Minnesota Hospital and Clinic, Minneapolis (USA))

    1991-03-01

    Transplantation of the pancreas is an increasingly common therapeutic option for preventing or delaying complications of type I diabetes mellitus. The authors studied the relative roles of various radiologic examinations in diagnosing vascular complications in these grafts including arterial and venous thrombosis, stenosis, and anastomotic leak (the most common vascular factors that necessitate pancreatectomy of the transplant), as defined with pathologic or arteriographic data. The results of 78 scintigraphic flow studies, 40 abdominal and pelvic computed tomographic (CT) scans, 27 sonograms, and eight color Doppler studies were evaluated in 52 patients who received a total of 27 cadaveric and 26 living-donor grafts over a 12-year period. These results were correlated with the data from 45 gross and microscopic pathologic studies and 37 arteriograms to determine their relative value in enabling detection of graft thrombosis and other vascular complications. Scintigraphy, CT, sonography, and color Doppler were all sensitive in detection of generalized graft abnormalities but lacked specificity in defining the underlying etiologic factors.

  16. Comparison of Right and Left Grafts in Renal Transplantation

    Directory of Open Access Journals (Sweden)

    Salehipour Mehdi

    2008-01-01

    Full Text Available This study compares outcomes and graft function of right and left grafts of deceased donor. We studied 120 kidney recipients from 60 deceased donors in Shiraz organ transplantation center from 1988 to 2004. We analyzed data regarding age, gender, side of grafts, duration of pre-transplant dialysis, hospital stay, serial creatinine levels, cold ischemic time, complications, graft function, patient survival rates, and post-operative complications. Recipients were divided into two groups: group 1 consisted of 60 recipients who received right renal graft (43 males, 17 females; mean age: 33.6 ± 7.3 years, and group 2 consisted of 60 recipients who received left renal graft (45 males, 15 females; mean age: 29.2 ± 6.4 years. No statistically significant differences were found in duration of pre-transplant dialysis, cold ischemic time, acute rejection rates, post-operative surgical and vascular complications′ rates, hospital stay, renal function, and one year graft survival rates. We conclude that although it is advised to use left kidney from live donors because of longer vessel length, easier surgical technique and organ handling, and shorter ischemic time, we got the same outcome in left and right deceased renal grafts.

  17. Hamstring Graft Incorporation According to the Length of the Graft Inside Tunnels.

    Science.gov (United States)

    Cavaignac, Etienne; Marot, Vincent; Faruch, Marie; Reina, Nicolas; Murgier, Jérôme; Accadbled, Franck; Berard, Emilie; Chiron, Philippe

    2018-02-01

    Anterior cruciate ligament (ACL) reconstruction with a quadrupled semitendinosus (ST4) graft is an evolution of the standard technique with 2 hamstring tendons (semitendinosus + gracilis [STG]). However, there is no published comparison of how well these 2 types of hamstring grafts are incorporated into the bone tunnels. Because the ST4 graft is shorter, there is less graft material inside the tunnels. To use magnetic resonance imaging (MRI) to compare graft incorporation in the tibial bone tunnels 1 year after ACL reconstruction with either an STG graft or ST4 graft. Cohort study; Level of evidence, 2. Sixty-two patients who underwent ACL reconstruction were enrolled prospectively: 31 with an ST4 graft and 31 with an STG graft. The same surgical technique, fixation method, and postoperative protocol were used in both groups. Graft incorporation and ligamentization were evaluated with MRI after 1 year of follow-up. The following parameters were evaluated: signal-to-noise quotient (SNQ), tibial tunnel enlargement, signal intensity at the bone-graft interface, and graft signal according to the Howell scale. The number of participants needed to show that the mean SNQ did not differ between the 2 techniques was 31 in each group (with a 1-sided alpha of 2.5% and a 1-sided beta of 10.0%). The Student t test was used to compare the distribution of continuous secondary endpoints. The mean SNQ was 5.2 ± 4.5 for the STG group and 5.9 ± 3.7 for the ST4 group ( P = .5100). The mean tibial tunnel widening was 93.7% ± 51.7% for the STG group versus 80.0% ± 42.9% for the ST4 group ( P = .2605). The groups did not differ in signal intensity at the bone-graft interface ( P = .7502) or in graft signal according to the Howell scale ( P = .4544). At the 1-year postoperative follow-up, incorporation and ligamentization of the STG and ST4 grafts were the same based on MRI analysis. The results were at least as good with the ST4 technique as with the standard STG technique in terms

  18. MDCT angiography with 3D image reconstructions in the evaluation of failing arteriovenous fistulas and grafts in hemodialysis patients

    Energy Technology Data Exchange (ETDEWEB)

    Dimopoulou, Angeliki; Raland, Hans; Magnusson, Anders (Dept. of Radiology, Univ. Hospital, Uppsala (Sweden)), email: angeliki.dimopoulou@akademiska.se; Wikstroem, Bjoern (Dept. of Medical Sciences, Renal Section, Univ. Hospital, Uppsala (Sweden))

    2011-11-15

    Background. Arteriovenous fistulas and grafts are the methods of choice for vascular access in renal failure patients in need of hemodialysis. Their major complication, however, is stenosis, which might lead to thrombosis. Purpose. To demonstrate the usefulness of 16-MDCTA with 3D image reconstructions, in long-term hemodialysis patients with dysfunctional arteriovenous fistulas and grafts (AVF and AVG). Material and Methods. During a 17-month period, 31 patients with dysfunctional AVF and AVG (24 AVF and seven AVG) were examined with MDCTA with 3D image postprocessing. Parameters such as comprehension of the anatomy, quality of contrast enhancement, and pathological vascular changes were measured. DSA was then performed in 24 patients. Results. MDCTA illustrated the anatomy of the AVF/AVG and the entire vascular tree to the heart, in a detailed and comprehensive manner in 93.5% of the evaluated segments, and depicted pathology of AVF/AVG or pathology of the associated vasculature. MDCTA demonstrated a total of 38 significant stenoses in 25 patients. DSA verified 37 stenoses in 24 patients and demonstrated two additional stenoses. MDCTA had thus a sensitivity of 95%. All 24 patients were treated with percutaneous transluminal angioplasty (PTA) with good technical results. Conclusion. MDCTA with 3D reconstructions of dysfunctioning AVFs and AVGs in hemodialysis patients is an accurate and reliable diagnostic method helping customize future intervention

  19. VASCULAR SURGERY

    African Journals Online (AJOL)

    Venous thromboembolism (VTE) is a complex and serious condition encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE), usually in the lower extremities.1,2. Thromboses can result from venous stasis, vascular injury or hypercoagulability, and those involving the deep veins proximal to the knee are ...

  20. [Retinal vascular tumors in the material of the Department of Ophthalmology and Ocular Oncology of Jagiellonian University Collegium Medicum in Cracow].

    Science.gov (United States)

    Leśniak, Anna; Karska-Basta, Izabella; Kobylarz, Joanna; Romanowska-Dixon, Bożena

    2015-01-01

    Retinal vascular tumours are congenital and acquired lesions of variable clinical manifestation. They are classified as benign, but their presence leads to vision impairment due to the development of complications. Each retinal vascular tumour possesses characteristic clinical features and is often associated with certain systemic disorders. Thus, a correct diagnosis is crucial for providing individualised treatment and expanded diagnostic management as well as prognostic assessment. The aim of the study was to present retinal vascular tumour cases of patients treated at the Department of Ophtalmology and Ocular Oncology of Jagiellonian University Collegium Medicum in Cracow.

  1. Effect, Feasibility, and Clinical Relevance of Cell Enrichment in Large Volume Fat Grafting

    DEFF Research Database (Denmark)

    Rasmussen, Bo Sonnich; Lykke Sørensen, Celine; Vester-Glowinski, Peter Viktor

    2017-01-01

    Large volume fat grafting is limited by unpredictable volume loss; therefore, methods of improving graft retention have been developed. Fat graft enrichment with either stromal vascular fraction (SVF) cells or adipose tissue-derived stem/stromal cells (ASCs) has been investigated in several animal...... and human studies, and significantly improved graft retention has been reported. Improvement of graft retention and the feasibility of these techniques are equally important in evaluating the clinical relevance of cell enrichment. We conducted a systematic search of PubMed to identify studies on fat graft...... enrichment that used either SVF cells or ASCs, and only studies reporting volume assessment were included. A total of 38 articles (15 human and 23 animal) were included to investigate the effects of cell enrichment on graft retention as well as the feasibility and clinical relevance of cell-enriched fat...

  2. Tendon grafts: their natural history, biology and future development.

    Science.gov (United States)

    Wong, R; Alam, N; McGrouther, A D; Wong, J K F

    2015-09-01

    The use of tendon grafts has diminished as regimes of primary repairs and rehabilitation have improved, but they remain important in secondary reconstruction. Relatively little is known about the cellular biology of grafts, and the general perception is that they have little biological activity. The reality is that there is a wealth of cellular and molecular changes occurring with the process of engraftment that affect the quality of the repair. This review highlights the historical perspectives and modern concepts of graft take, reviews the different attachment techniques and revisits the biology of pseudosheath formation. In addition, we discuss some of the future directions in tendon reconstruction by grafting, which include surface modification, vascularized tendon transfer, allografts, biomaterials and cell-based therapies. © The Author(s) 2015.

  3. Preparation and characterization of a novel bone graft composite ...

    Indian Academy of Sciences (India)

    Egg shells which were hitherto discarded as wastes were collected, purified and powdered into a particle size in the range of 5–50 m. A composite bone graft material in cylindrical form was prepared using egg shell powder (ESP), bone ash (BA) and gelatin. These bone grafts were characterized for their FT–IR, TGA, XRD ...

  4. Top Grafting Loblolly Pine in the Western Gulf Region

    Science.gov (United States)

    Geoffrey D. Goading; Floyd E. Bridgwater; David L. Bramlett; William J. Lowe

    1999-01-01

    Flowering data were collected from top grafts made in 1996 and 1997 at the Mississippi Forestry Commission's Craig Seed Orchard near Lumberton, MS. Scion material from twenty loblolly pine (Pinus taeda) second-generation selections was grafted onto five loblolly pine and five slash pine (P. elliottii) interstocks. All...

  5. Preformed hydroxylapatite blocks for palatal grafting in orthognathic surgery.

    Science.gov (United States)

    Hiatt, W R; Moore, D L; Mosby, E L; Fain, D W

    1987-06-01

    Hydroxylapatite has been used as a bone substitute for ridge augmentation, ridge maintenance and periodontal defects for many years. This is a preliminary report of the use of hydroxylapatite blocks as a grafting material in midpalatal splits in orthognathic surgery. With the advent of hydroxylapatite blocks, the need for autogenous bone grafting will, in most cases, be obviated.

  6. Evolution of instruments for harvest of the skin grafts

    Directory of Open Access Journals (Sweden)

    Faisal Ameer

    2013-01-01

    Full Text Available Background: The harvest of autologous skin graft is considered to be a fundamental skill of the plastic surgeon. The objective of this article is to provide an interesting account of the development of skin grafting instruments as we use them today in various plastic surgical procedures. Materials and Methods: The authors present the chronological evolution and modifications of the skin grafting knife, including those contributions not often cited in the literature, using articles sourced from MEDLINE, ancient manuscripts, original quotes, techniques and illustrations. Results: This article traces the evolution of instrumentation for harvest of skin grafts from free hand techniques to precise modern automated methods. Conclusions: Although skin grafting is one of the basic techniques used in reconstructive surgery yet harvest of a uniform graft of desired thickness poses a challenge. This article is dedicated to innovators who have devoted their lives and work to the advancement of the field of plastic surgery.

  7. Synthesis and characterization of electrical conducting chitosan-graft-polyaniline

    Directory of Open Access Journals (Sweden)

    2007-05-01

    Full Text Available A mucopolysaccharide, chitosan was grafted with polyaniline through oxidative-radical copolymerization using ammonium persulfate in acidic medium. The grafting conditions were extensively studied by varying grafting parameters. All the findings have been discussed and proposed a plausible mechanism for the graft copolymerization. The representative chitosan-graft-polyaniline (Ch-g-PANI was characterized using UV-vis, FTIR, TGA, X-ray diffraction and Scanning electron microscopy taking chitosan as reference. Ch-g-PANI exhibited electrical conductivity, which increases with the extent of grafting onto chitosan backbone. Its electrical conductivity is further influenced by pH and showed pH switching electrical conduction behavior when exposed to NN3/HCl vapors. The application of conducting biomaterial such as Ch-g-PANI in the electronic devices especially for the fabrication of sensor devices would be attractive not only in terms of product cost and environmental safety but also from a materials science point of view.

  8. R&D for graft adsorbents by radiation processing

    Science.gov (United States)

    Seko, Noriaki; Tamada, Masao

    Fibrous adsorbent for removal and recovery of metal ions have been synthesized by graft polymerization. In the grafting, the functional groups which have high selectivity against for target metal ions such as Fe, Sc, As, and U are introduced onto nonwoven fabric. When the monomer has a chelate group which makes selective coordination bond to specific these ions, it was directly grafted on the trunk polymer. In the case of precursor monomer having functional groups such as epoxy ring, the grafted trunk fabric is chemically modified. The resultant fibrous adsorbent leads the swift adsorption of metal ions. This property by using fibrous material can reduce the column size of adsorbent in the purification of waste water. The size of purification equipment becomes quite compact and that implies total volume of equipment can reduce. Instead of organic solvent, emulsion system which disperses monomer micelles in water with assistance of surfactant was found to accelerate the graft polymerization. This means the air pollution from organic solvent can be avoided by water system grafting. Furthermore, since the emulsion grafting was highly efficient, the required irradiation dose was considerably lower compared to general organic solvent system. As a result, the emulsion grafting has enormous potential for natural polymer to use as a trunk material for grafting. If a natural polymer such as cellulose can be used, the dependence on petroleum resources, the amount of industrial waste and the generation of carbon dioxide will be reduced to some extent.

  9. Gamma radiation grafted polymers for immobilization of Brucella antigen in diagnostic test studies

    Science.gov (United States)

    Docters, E. H.; Smolko, E. E.; Suarez, C. E.

    The radiation grafting process has a wide field of industrial applications, and in the recent years the immobilization of biocomponents in grafted polymeric materials obtained by means of ionizing radiations is a new and important contribution to biotechnology. In the present work, gamma preirradiation grafting method was employed to produce acrylics hydrogels onto polyethylene (PE), polyvinyl chloride (PVC) and polystyrene (PS). Two monomers were used to graft the previously mentioned polymers: methacrylic acid (MAAc) and acrylamide (AAm), and several working conditions were considered as influencing the degree of grafting. All this grafted polymers were used to study the possibility of a subsequent immobilization of Brucella antigen (BAg) in diagnostic test studies (ELISA).

  10. Subantral bone grafts, a comparative study of the degree of resorption of alloplastic versus autologous grafts.

    Science.gov (United States)

    Onişor-Gligor, Florin; Juncar, Mihai; Câmpian, Radu Septimiu; BăciuŢ, Grigore; Bran, Simion; BăciuŢ, Mihaela Felicia

    2015-01-01

    The placement of dental implants in the posterior region of the maxillary may pose some difficulties caused by the quality and particularly, the quantity of the subantral bone reserve, which are overcome by subantral bone augmentation. The current study performs a comparative evaluation of the quality and especially, of the stability of alloplastic and autologous materials used for subantral bone augmentation. This study included 21 patients who underwent subantral bone augmentation with alloplastic and autologous material. The patients were followed-up over a 24-month period after bone augmentation, during which the osseointegration rate of dental implants and the stability of subantral grafts were evaluated. The rate of failure of dental implants placed in autologous material grafts was 1.89% (0.036±9.398), while the rate of failure of those placed in alloplastic material was 7.69% (1.960±19.194). Bone resorption was higher within 12 months of dental implant placement both for the alloplastic material (9.87±3.76%) and the autologous material (18.87±3.25%), while 12-24 months after bone augmentation it diminished. The implants placed in the autologous bone grafts had a lower rate of failure compared to those placed in the alloplastic material grafts; in contrast, alloplastic material had a lower resorption rate compared to autologous material.

  11. The efficacy of aspirin and dipyridamole on the patency of arteriovenous fistulae and grafts; Review of the randomized control trials

    Directory of Open Access Journals (Sweden)

    Hasan Ravari

    2014-07-01

    Full Text Available Vascular access failure is known as a principal cause of morbidity of end stage renal disease (ESRD patients. The major reason for vascular access failure is the neointimal hyperplasia which leads to venous thrombosis and stenosis. The efficacy of different pharmacological therapies has been studied in increasing the vascular access patency duration or decreasing the thrombosis of arteriovenous grafts or fistulas. In the current review, we reviewed the results obtained in different randomized control trials considering the efficacy of pharmacotherapy on the thrombosis rate and duration of vascular access grafts patency in HD patients.

  12. [Bone-tendon integration of autologous grafts using different diameter tunnels. An experimental study on sheep].

    Science.gov (United States)

    Sánchez Hidalgo, R; Forriol, F

    2012-01-01

    To analyse the bone-ligament integration «ligamentization» of the tendon graft in the reconstruction of anterior cruciate ligament (ACL) performing tunnels of different diameter. We performed the same reconstruction procedure using an autologous tendon graft taken from the superficial tendon of the hoof in 41 adult sheep. In Group A the tibial and femoral tunnels were 5 mm in diameter and in Group B they were 7 mm in diameter. The sheep were sacrificed at 3, 6 and 12 months after the surgery. Histological studies were performed on the graft and the tunnels, as well as a biomechanical analysis of the tibial-femoral complex. In group A we did not observe direct integration of the bone and the tendon graft or any fibres joining both structures, although there was vascularized fibrous tissue. In group B we did not observe any direct binding of the bone and the tendon graft either, although there was abundant fibrous tissue. The tendon graft showed a fascicular structure that increased over time in order to create septa for vascular penetration. Macroscopically the ACL graft had a dense appearance, which was very similar to the original tendon graft. The tendon grafts from group B and with a longer follow up period required a higher strength to produce maximum breakage than the tendon grafts from group A. After one year follow up, the histological study shows that the tendon graft is not transformed into a ligament, and there is no integration of the tendon graft in tunnels regardless of their diameter. Therefore, fixation techniques are essential to maintain the orientation and tension of the tendon graft. Copyright © 2011 SECOT. Published by Elsevier Espana. All rights reserved.

  13. Effect of Grafting Method, Graft Cover and Foliar Spray of some Mineral Elements on Persian Walnut Graft-take and Winter Survival Rate

    Directory of Open Access Journals (Sweden)

    Reza Rezaee

    2017-02-01

    Full Text Available Introduction: Persian walnut (Juglans regia L. is an important nut crop in Iran and many parts of the world. One of the major challenges of growing walnut is planting of non-grafted walnut trees in orchards, which leads to the reduction of yield, quality and productivity of walnut orchards. Compared to the other fruit trees, walnut grafting is difficult and even newly grafted walnut seedlings are vulnerable to fall or winter frost chilling, so that most of the seedlings are lost after subjecting to the cold winter. There are a few studies reporting successful grafting in outdoor conditions, however, final grafting take after winter has been usually ignored. Hence, increased walnut grafting success and improved tree growth after grafting through foliar nutrient application may lead to increased tolerance of chilling. Therefore, main goals of this research were to investigate the effect of some graft covers and role of foliar spray of calcium, boron and zinc on the reduction of frost damage in newly grafted seedlings under outdoor conditions. Materials and methods: This research was conducted at agricultural research station, Khoy city, west Azerbaijan province, during 2012-2014. In the first experiment, three methods of grafting including cleft, bark and V-shaped, and two kinds of graft covers including moist sawdust and superabsorbent plus cotton wool were investigated in terms of grafting success and quality of seedlings. In the second experiment, effect of the three above-mentioned grafting methods and two levels of foliar spray including sequential spray of Ca (4 ppm, B and Zn (2% (3 times during growth season and control (no spray were studied in terms of frost damage. The experiments conducted in factorial based on randomized complete block design with 10 trees in each plot. Data were collected 45 days after grafting take, final grafting take after one winter, subsequent scion growth length and diameter and concentration of Ca, B and Zn in

  14. Tissue Responses to Stent Grafts with Endo-Exo-Skeleton for Saccular Abdominal Aortic Aneurysms in a Canine Model

    OpenAIRE

    Kim, Young Il; Choi, Young Ho; Chung, Jin Wook; Kim, Hyo-Cheol; So, Young Ho; Kim, Hyun Beom; Min, Seung-Kee; Park, Jae Hyung

    2014-01-01

    Objective We evaluated the effect of close contact between the stent and the graft on the induction of endothelial covering on the stent graft placed over an aneurysm. Materials and Methods Saccular abdominal aortic aneurysms were made with Dacron patch in eight dogs. The stent graft consisted of an inner stent, a expanded polytetrafluoroethylene graft, and an outer stent. After sacrificing the animals, the aortas with an embedded stent graft were excised. The aortas were inspected grossly an...

  15. Vascular complication in live related renal transplant: An experience of 1945 cases

    Directory of Open Access Journals (Sweden)

    Aneesh Srivastava

    2013-01-01

    Conclusions: Major vascular complications are relatively uncommon after renal transplantation but still constitute an important cause of graft loss in early postoperative period. Aneurysm and vessel thrombosis usually require graft nephrectomy. Transplant renal artery stenosis is amenable to correction by endovascular techniques.

  16. Alveolar graft in the cleft lip and palate patient: Review of 104 cases

    Science.gov (United States)

    Tobella-Camps, María L.; Rivera-Baró, Alejandro

    2014-01-01

    Introduction: Alveolar bone grafting is a vital part of the rehabilitation of cleft patients. The factors that have been most frequently associated with the success of the graft are the age at grafting and the pre-grafting orthodontic treatment. Objectives: 1) Describe the cases of alveolar bone grafts performed at the Maxilofacial Unit of Hospital Sant Joan de Déu, Barcelona (HSJD); and 2) Analyze the success/failure of alveolar grafts and related variables. Material and Methods: Descriptive retrospective study using a sample of 104 patients who underwent a secondary alveolar graft at the Craniofacial Unit of HSJD between 1998 and 2012. The graft was done by the same surgeon in all patients using bone from the iliac crest. Results: 70% of the patients underwent the procedure before the age of 15 (median 14.45 years); 70% of the graft patients underwent pre-graft maxillary expansion. A total of 100 cases were recorded as successful (median age of 14.58 years, 68 underwent pre-graft expansion) and only 4 were recorded as failures (median age of 17.62 years, 3 underwent pre-graft expansion). We did not find statistically significant differences in age at the time of grafting or pre-surgical expansion when comparing the success and failure groups. We found the success rate of the graft to be 96.2%. Conclusions: The number of failures was too small to establish a statistically significant conclusion in our sample regarding the age at grafting and pre-grafting expansion. The use of alveolar bone grafting from the iliac crest has a very high success rate with a very low incidence of complications. Existing controversies regarding secondary bone grafting and the wide range of success rates found in the literature suggest that it is necessary to establish a specific treatment protocol that ensures the success of this procedure. Key words:Alveolar graft, cleft lip and palate, alveolar cleft, alveolar defect. PMID:24880440

  17. Endovascular Revascularization of Hemodialysis Thrombosed Grafts with the Hydrodynamic Thrombectomy Catheter. Our 7-Year Experience

    Energy Technology Data Exchange (ETDEWEB)

    Bermudez, Patrícia, E-mail: pbermude@clinic.ub.es [Clinic Hospital of Barcelona, Vascular and Interventional Radiology Unit, Diagnostic Imaging Institute (Spain); Fontseré, Nestor, E-mail: fontsere@clinic.ub.es [Clinic Hospital of Barcelona, Vascular Access Unit, Nephrologic and Urologic Diseases Clinical Institute (Spain); Mestres, Gaspar, E-mail: gmestres@clinic.ub.es [Clinic Hospital of Barcelona, Cardiovascular Diseases Institute (Spain); García-Gámez, Andres, E-mail: garciagam@clinic.ub.es; Barrufet, Marta, E-mail: barrufet@clinic.ub.es; Burrel, Marta, E-mail: mburrel@clinic.ub.es; Gilabert, Rosa, E-mail: gilabert@clinic.ub.es; Gómez, Fernando, E-mail: fegomez@clinic.ub.es; Macho, Juan, E-mail: jmmacho@clinic.ub.es [Clinic Hospital of Barcelona, Vascular and Interventional Radiology Unit, Diagnostic Imaging Institute (Spain)

    2017-02-15

    PurposeTo evaluate the efficacy and safety of the hydrodynamic thrombectomy catheter (AngioJet DVX) in the salvage of thrombosed hemodialysis vascular grafts.Materials and MethodsA retrospective study was designed, including all patients with occluded arteriovenous grafts treated with the AngioJet system between 2007 and 2014 in our institution. Outcomes included technical success, clinical success, complications, and primary and secondary patencies. Procedural success was defined as angiographic confirmation of flow restoration, the presence of a pulsatile thrill along the graft, and successful resumption of at least one hemodialysis session. Primary and secondary patencies after first AVG thrombectomy were calculated with Kaplan–Meier curves. Cox regression was used to determine prognostic factors of primary patency after every thrombectomy episode.ResultsA total of 149 thrombectomies were performed in 68 grafts. After thrombectomy, endovascular treatment of one or more stenosis was performed in all cases. Technical success was 93% and clinical success was 86%. Complications occurred in 7 thrombectomies, most of them were minor except for one anastomosis rupture requiring surgery. Primary and secondary patencies were 52, 41, and 23 and 76, 68, and 57% at 3, 6 and 12 months, respectively. Independent prognostic factors of poor patency after every thrombectomy episode were the presence of residual thrombus (OR 1.831, P = 0.008) and time from last thrombosis (less than 1 month; and OR 7.116, P < 0.001).ConclusionPercutaneous mechanical thrombectomy with AngioJet is a safe technique with a high-clinical success rate. The presence of residual thrombus after thrombectomy and early re-occlusions are related to poorer results.

  18. Melting graft wound syndrome

    Directory of Open Access Journals (Sweden)

    Shiou-Mei Chen

    2017-09-01

    Full Text Available Melting graft wound syndrome is characterized by progressive epidermal loss from a previously well-taken skin graft, healed burn, or donor site. It may result in considerable morbidity and require prolonged treatment. We report a 23-year-old flame-burned patient with second- to third-degree burns involving more than 70% of the total body surface area, whose condition was complicated with septic shock. The patient presented with erosions and ulcers occurring on previously well-taken skin graft recipient sites over both legs and progressive epidermal loss on donor sites over the back. The patient's presentation was compatible with the diagnosis of melting graft wound syndrome, and we successfully treated the patient with debridement and supportive treatment.

  19. Molecular Imaging of VEGF Receptors in Graft Arteriosclerosis

    Science.gov (United States)

    Zhang, Jiasheng; Razavian, Mahmoud; Tavakoli, Sina; Nie, Lei; Tellides, George; Backer, Joseph M.; Backer, Marina V.; Bender, Jeffrey R.; Sadeghi, Mehran M.

    2012-01-01

    Objectives Vascular endothelial growth factor (VEGF) signaling plays a key role in the pathogenesis of vascular remodeling, including graft arteriosclerosis (GA). GA is the major cause of late organ failure in cardiac transplantation. We used molecular near-infrared fluorescent (NIRF) imaging with an engineered Cy5.5-labeled single-chain VEGF tracer (scVEGF/Cy) to detect VEGF receptors (VEGFRs) and vascular remodeling in human coronary artery grafts by molecular imaging. Methods and Results VEGFR-specificity of probe uptake was shown by flow cytometry in endothelial cells. In severe combined immunodeficiency mice, transplantation of human coronary artery segments into the aorta followed by adoptive transfer of allogeneic human peripheral blood mononuclear cells (PBMCs) led to significant neointima formation in the grafts over a period of 4 weeks. NIRF imaging of transplant recipients at 4 weeks demonstrated focal uptake of scVEGF/Cy in remodeling artery grafts. Uptake specificity was demonstrated using an inactive homologue of scVEGF/Cy. scVEGF/Cy uptake predominantly localized in the neointima of remodeling coronary arteries and correlated with VEGFR-1, but not VEGFR-2 expression. There was a significant correlation between scVEGF/Cy uptake and transplanted artery neointima area. Conclusions Molecular imaging of VEGF receptors may provide a non-invasive tool for detection of GA in solid organ transplantation. PMID:22723442

  20. Two-Stage Nerve Graft in Severe Scar: A Time-Course Study in a Rat Model

    Directory of Open Access Journals (Sweden)

    Shayan Zadegan

    2015-04-01

    According to the EPT and WRL, the two-stage nerve graft showed significant improvement (P=0.020 and P =0.017 respectively. The TOA showed no significant difference between the two groups. The total vascular index was significantly higher in the two-stage nerve graft group (P

  1. Covalent grafting of phenylphosphonate on calcium niobate platelets.

    Science.gov (United States)

    Shori, Shailesh; Pellechia, Perry J; zur Loye, Hans-Conrad; Ploehn, Harry J

    2015-01-01

    This work explores covalent grafting of phenylphosphonate (PPA) onto exfoliated, protonated calcium niobate (HCN), a Dion-Jacobson layered perovskite. The specific hypothesis is that PPA can be readily grafted onto the face surfaces of exfoliated HCN, which has reactive apical oxygen atoms. Previous research has established the conditions required for full exfoliation of HCN in aqueous solutions of tetrabutylammonium hydroxide (TBAOH), denoted as TBACN. This work first explores the effect of reflux conditions on the dispersion state of TBACN suspensions, and then investigates PPA grafting onto both non-exfoliated HCN and exfoliated TBACN dispersed in deionized (DI) water, TBA solution, and various alcohols. The products are characterized by a variety of techniques including light scattering to assess the TBACN dispersion state, (31)P MAS NMR to confirm PPA grafting, and XPS to estimate PPA grafted amounts. The results confirm the grafting of PPA on HCN and TBACN, quantify the extent of PPA grafting, and identify various grafting modes (mono-, bi-, and tridentate). All of these aspects are found to be dependent on the layered materials' exfoliation state, suspension processing conditions, and solvent composition. The results are rationalized in terms of a plausible mechanism of the grafting process. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Magnetizable stent-grafts enable endothelial cell capture

    Energy Technology Data Exchange (ETDEWEB)

    Tefft, Brandon J. [Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States); Uthamaraj, Susheil [Division of Engineering, Mayo Clinic, Rochester, MN (United States); Harburn, J. Jonathan [School of Medicine, Pharmacy and Health, Durham University, Stockton-on-Tees (United Kingdom); Hlinomaz, Ota [Department of Cardioangiology, St. Anne' s University Hospital, Brno (Czech Republic); Lerman, Amir [Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States); Dragomir-Daescu, Dan [Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN (United States); Sandhu, Gurpreet S., E-mail: sandhu.gurpreet@mayo.edu [Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (United States)

    2017-04-01

    Emerging nanotechnologies have enabled the use of magnetic forces to guide the movement of magnetically-labeled cells, drugs, and other therapeutic agents. Endothelial cells labeled with superparamagnetic iron oxide nanoparticles (SPION) have previously been captured on the surface of magnetizable 2205 duplex stainless steel stents in a porcine coronary implantation model. Recently, we have coated these stents with electrospun polyurethane nanofibers to fabricate prototype stent-grafts. Facilitated endothelialization may help improve the healing of arteries treated with stent-grafts, reduce the risk of thrombosis and restenosis, and enable small-caliber applications. When placed in a SPION-labeled endothelial cell suspension in the presence of an external magnetic field, magnetized stent-grafts successfully captured cells to the surface regions adjacent to the stent struts. Implantation within the coronary circulation of pigs (n=13) followed immediately by SPION-labeled autologous endothelial cell delivery resulted in widely patent devices with a thin, uniform neointima and no signs of thrombosis or inflammation at 7 days. Furthermore, the magnetized stent-grafts successfully captured and retained SPION-labeled endothelial cells to select regions adjacent to stent struts and between stent struts, whereas the non-magnetized control stent-grafts did not. Early results with these prototype devices are encouraging and further refinements will be necessary in order to achieve more uniform cell capture and complete endothelialization. Once optimized, this approach may lead to more rapid and complete healing of vascular stent-grafts with a concomitant improvement in long-term device performance. - Highlights: • Magnetic stent-grafts were made from 2205 steel stents and polyurethane nanofibers. • Stent-grafts remained patent and formed a thin and uniform neointima when implanted. • Stent-grafts captured endothelial cells labeled with magnetic nanoparticles.

  3. Synthetic dural graft septoplasty in epistaxis from hereditary hemorrhagic telangiectasia.

    Science.gov (United States)

    Burckhardt B, Wilfred; Guerra, Claudia Patricia

    2013-07-01

    It is an autosomal dominant vascular disorder, which has a variety of clinical manifestations, with epistaxis being one of the most common. Many treatment options exist for epistaxis, but with no consensus on which is the method of choice. We describe the case of a patient with hereditary hemorrhagic telangiectasia (HHT) secondary epistaxis with septoplasty managed with synthetic hard graft, which improved intensity and frequency of bleeding episodes. This technique is a variant of the septodermoplasty described by several authors, but the use of synthetic dura can help in obtaining better results and avoid taking skin grafts from other sites different from the surgical site.

  4. Treatment of localized gingival recessions using gingival unit grafts: a randomized controlled clinical trial.

    Science.gov (United States)

    Kuru, Bahar; Yıldırım, Selin

    2013-01-01

    One of the success factors in periodontal plastic surgery is the synergistic relationship between involved tissues and vascular supply. Gingiva as a functional unit is unique with a specific vascular configuration and contains the supracrestal portion naturally created to survive over avascular root surfaces. The aim of this randomized controlled trial is to clinically evaluate the treatment of localized gingival recessions by using gingival unit grafts (palatal tissue involving marginal gingiva and papillae) compared with conventional palatal grafts. Seventeen patients with Class I to II recession defects on mandibular anterior teeth were included and randomly divided into two groups. Recessions were treated with gingival unit grafts in group 1 (n = 8) and with palatal grafts in group 2 (n = 9). Clinical parameters including vertical recession (VR), probing depth, keratinized tissue (KT), and attachment level were recorded at baseline and 8 months after surgery. Both treatments produced significant clinical improvements within the groups. Intergroup comparison revealed significantly higher VR reduction, attachment, and KT gain in group 1 than in group 2; mean percentages of the defect coverage were 91.62% ± 9.74% and 68.97% ± 13.67%, respectively (P <0.05). Healing of the gingival unit donor site was uneventful. Within its limits, this study demonstrates the possibility of treating buccal recessions with gingival unit grafts as an alternative technique using gingival donor graft of site-specific vascular configuration, with better defect coverage, clinical, and esthetic improvements compared with palatal grafts.

  5. New Options for Vascularized Bone Reconstruction in the Upper Extremity

    Science.gov (United States)

    Houdek, Matthew T.; Wagner, Eric R.; Wyles, Cody C.; Nanos, George P.; Moran, Steven L.

    2015-01-01

    Originally described in the 1970s, vascularized bone grafting has become a critical component in the treatment of bony defects and non-unions. Although well established in the lower extremity, recent years have seen many novel techniques described to treat a variety of challenging upper extremity pathologies. Here the authors review the use of different techniques of vascularized bone grafts for the upper extremity bone pathologies. The vascularized fibula remains the gold standard for the treatment of large bone defects of the humerus and forearm, while also playing a role in carpal reconstruction; however, two other important options for larger defects include the vascularized scapula graft and the Capanna technique. Smaller upper extremity bone defects and non-unions can be treated with the medial femoral condyle (MFC) free flap or a vascularized rib transfer. In carpal non-unions, both pedicled distal radius flaps and free MFC flaps are viable options. Finally, in skeletally immature patients, vascularized fibular head epiphyseal transfer can provide growth potential in addition to skeletal reconstruction. PMID:25685100

  6. Electrospun biphasic tubular scaffold with enhanced mechanical properties for vascular tissue engineering.

    Science.gov (United States)

    Abdal-Hay, Abdalla; Bartnikowski, Michal; Hamlet, Stephen; Ivanovski, Sašo

    2018-01-01

    Polymer scaffolds produced through an electrospinning process are frequently explored as tissue substitutes for regenerative medicine. Despite offering desirable surface area to volume ratios and tailorable pore sizes, their poor structural mechanical properties limit their applicability in load-bearing regions. In this study, we present a simple strategy to improve the mechanical properties of a vascular graft scaffold. We achieved the formation of biphasic tubular scaffolds by electrospinning polyurethane (PU) onto an airbrushed tube made of polycaprolactone (PCL). After preparation, the scaffold was subsequently thermally-crosslinked (60°C) to strengthen the bonding between the two materials. The tensile strength and tensile elastic (Young's) modulus of the biphasic scaffolds were significantly enhanced from 4.5±1.72 and 45±15MPa (PU-only) up to 67.5±2.4 and 1039±81.8MPa (PCL/PU; pmechanically robust vascular graft scaffold using a novel combination of well-established fabrication techniques. This study could also be extended to the fabrication of other biphasic scaffolds to better enhance the mechanical properties of the electrospun fibers mat without deteriorating its architecture structure. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Bone ingrowth and vascular supply in experimental spinal fusion with platelet-rich plasma.

    Science.gov (United States)

    Cinotti, Gianluca; Corsi, Alessandro; Sacchetti, Benedetto; Riminucci, Mara; Bianco, Paolo; Giannicola, Giuseppe

    2013-03-01

    Prospective investigation using a posterolateral spinal fusion (PLSF) model in rabbits. To assess the effects of platelet-rich plasma (PRP) alone, or with uncultured bone marrow, on bone ingrowth and angiogenesis in experimental PLSF. PRP is an autologous substance potentially beneficial to spinal fusion, because it includes several growth factors that may stimulate bone ingrowth and angiogenesis. However, the results of experimental and clinical investigations on the effectiveness of PRP in spinal fusion are controversial. This study was aimed at analyzing the influence of PRP on bone ingrowth and angiogenesis in experimental PLSF. Twenty White New Zealand rabbits underwent PLSF at L4-L5 level. The graft material included a ceramic carrier (Pro-Osteon 500R) loaded, in 7 rabbits, with PRP alone on the right side (group 1A) and with uncultured bone marrow in the left side (group 1B). In 7 rabbits, the ceramic carrier was used alone in the right side (group 2A), and with uncultured bone marrow in the left side (group 2B). Six rabbits (group 3) were sham operated on both right and left sides. Six months after surgery, the lumbar spine was harvested en bloc and evaluated by high-resolution radiographs (Faxitron, Wheeling, IL) and histology. The radiographical outcome showed a fusion rate of 86% in groups 1A, 1B, and 2B and a fusion rate of 71% in group 2A. No specimen showed a solid fusion in the sham group. Histological analysis revealed new bone formation in the periapophyseal area in groups 1 and 2, but a complete bony bridge between the transverse processes was not observed in any specimen. In all groups, vascular density was significantly greater in the peri- compared with the interapophyseal region. In the PRP group, there was no evidence of increased vascular density in the grafted material compared with the other groups. In experimental PLSF model in rabbits, PRP was not effective in promoting new bone formation and vascularization.

  8. Coordination chemistry for antibacterial materials: a monolayer of a Cu(2+) 2,2'-bipyridine complex grafted on a glass surface.

    Science.gov (United States)

    Pallavicini, Piersandro; Dacarro, Giacomo; Grisoli, Pietro; Mangano, Carlo; Patrini, Maddalena; Rigoni, Federica; Sangaletti, Luigi; Taglietti, Angelo

    2013-04-07

    A propyltrimethoxysilane-modified 2,2'-bipyridine ligand is synthesized and its acetonitrile solutions are used to prepare monolayers of the molecule on glass surfaces. Absorption and X-ray photoelectron spectroscopy demonstrate that the modified glass surfaces bind Cu(2+) with a 1:1 ratio with respect to the 2,2'-bipyridine moieties under the chosen preparative conditions, producing materials bearing 0.016 μg cm(-2) of copper. Although in trace amounts, the bound Cu(2+) cations exert a significant microbicidal effect against Escherichia coli and Staphylococcus aureus.

  9. Contemporary Review of Grafting Techniques for the Surgical Treatment of Peyronie's Disease.

    Science.gov (United States)

    Hatzichristodoulou, Georgios; Osmonov, Daniar; Kübler, Hubert; Hellstrom, Wayne J G; Yafi, Faysal A

    2017-10-01

    Peyronie's disease (PD) is a benign fibrotic disorder of the tunica albuginea of the penis, which can cause penile pain, curvature, shortening, erectile dysfunction, and psychological distress. Surgery is indicated when penile curvature prevents satisfactory sexual intercourse. Plaque incision or excision with grafting has been suggested as an option in patients with a penile curvature greater than 60°, a shortened penis, and/or an hourglass or complex deformity. To provide an overview of recent studies reporting outcomes of grafting techniques and to report advances in the development of new grafting materials for PD surgery. A literature review was performed through PubMed from 2011 through 2016 regarding grafting techniques for PD. Key words used for the search were grafting techniques, grafts, graft materials, Peyronie's disease, surgical outcomes, and surgical therapy. To report on novel and promising graft materials for PD and to discuss surgical techniques, outcomes, and limitations. Discussed outcomes include postoperative penile straightening, shortening, erectile function, glans sensation, and patient satisfaction. Various surgical techniques and grafting materials can be used for the coverage of the tunica albuginea defect after partial plaque excision or incision. Autologous and non-autologous grafts have been used in this setting. A major advantage of the available "off-the-shelf" grafts is that they do not require donor site harvesting, thus decreasing morbidity and operative time. Tissue-engineered grafts represent the future, but more research is needed to further improve surgical handling and postoperative outcomes. Patients opting for grafting techniques should have sufficient erectile rigidity preoperatively. Surgeon experience, careful patient selection, patient preference, and type of penile deformity affect the choice of graft and surgical approach used. Hatzichristodoulou G, Osmonov D, Kübler H, et al. Contemporary Review of Grafting

  10. One-dimensional Arterial Network Model for Bypass Grafts Assessment

    CERN Document Server

    Ghigo, Arthur; Wang, Xiaofei; Lagrée, Pierre-Yves; Fullana, Jose-Maria

    2016-01-01

    We propose an arterial network model based on 1D blood hemodynamic equations to study the behavior of different vascular surgical bypass grafts in case of an arterial occlusive pathology: an obliteration or stenosis of the iliac artery. We investigate the performances of three different bypass grafts (Aorto-Femoral, Axillo-Femoral and cross-over Femoral) depending on the degree of obliteration of the stenosis. Numerical simulations show that all bypass grafts are efficient since we retrieve in all cases the normal hemodynamics in the stenosed region while ensuring at the same time a global healthy circulation. We analyze in particular the Axillo-Femoral bypass graft by performing hundreds of simulations by varying the values of the Young's modulus [0.1--50 MPa] and the radius [0.01--5 cm] of the bypass graft. We show that the Young's modulus and radius of commercial bypass grafts are optimal in terms of hemodynamic considerations. The numerical findings prove that this approach could be used to optimize or pl...

  11. GRAFT COMPATIBILITY BETWEEN EUROPEAN PEAR CULTIVARS AND EAST MALLING “C” ROOTSTOCK

    Directory of Open Access Journals (Sweden)

    BRUNO DALAZEN MACHADO

    2017-08-01

    Full Text Available ABSTRACT Graft incompatibility is one of the main factors limiting european pear production in Brazil. At present, there is no clear indication of the best combination(s of european pear cultivars and quince rootstocks for graft compatibility. The study evaluated the graft compatibility for combinations of european Abbè Fetel, Rocha and Williams pear cultivars grafted onto the EMC quince rootstock. The experiment was performed in a commercial european pear orchard in the Urupema municipality, in State of Santa Catarina, during the 2011/12, 2012/13 and 2013/14 growing seasons. The plant growth variables comprised the section increment (mm in the trunk diameter in the graft union region of cultivars and rootstocks; difference in the diameter of the graft for cultivars and rootstocks; “translocated” incompatibility; “located” incompatibility and the vascular connection in the graft union region, which was assessed by immersing the bases of the plants in a 0.08% succinic acid solution. There were “located” and “translocated” incompatibility between the european Williams pear cultivar and the EMC rootstock based on the vascular discontinuity in the graft union region, which prevented the translocation of succinic acid stain. Thus, the Williams/EMC combination is considered incompatible and it is not recommended for use in commercial orchards. The Rocha/EMC and Abbè Fetel/EMC are considered partially incompatible combinations and showed good development eight years after planting.

  12. Efficiency of sirolimus in prevention of adhesions around vascular ...

    African Journals Online (AJOL)

    Background: Adhesions due to the reactions caused by the grafts used in the primary vascular operation can lead to various problems when a secondary operation is necessary. These problems include: bleeding, injuries to neighboring organs sand complications occurring due to a prolonged operation. We investigated the ...

  13. Near-infrared spectroscopy during peripheral vascular surgery

    DEFF Research Database (Denmark)

    Eiberg, J P; Schroeder, T V; Vogt, K C

    1997-01-01

    Near-infrared spectroscopy was performed perioperatively on the dorsum of the foot in 14 patients who underwent infrainguinal bypass surgery using a prosthesis or the greater saphenous vein. Dual-wavelength continuous light spectroscopy was used to assess changes in tissue saturation before, during...... that near-infrared spectroscopy is appropriate for perioperative monitoring during vascular grafting....

  14. Epoxy and Silicone Optical Nanocomposites Filled with Grafted Nanoparticles

    Science.gov (United States)

    Tao, Peng

    Polymer nanocomposites, as a technologically important class of materials, exhibit diverse functional properties, and are used for applications ranging from structural and biomedical to electronic and optical. The properties of polymer nanocomposites are determined, in part, by the chemical composition of the polymer matrix and the nanofillers. Their properties are also sensitive to the geometry and size of the nanofillers, and to spatial distribution of the fillers. Control of the nanoparticle size and dispersion within a given polymer provides opportunities to tailor and optimize the properties of nanocomposites for specific application. For optical applications such as encapsulation of light emitting diodes (LEDs), polymer nanocomposites filled with homogeneously dispersed nanoparticles would endow the polymer encapsulant with new functionality without sacrificing optical transparency. To this end, this thesis focuses on developing a simple and versatile approach towards the fabrication of epoxy and silicone transparent nanocomposites using matrix compatible chain-grafted nanoparticles as fillers, and studying the optical properties of the nanocomposites. The surface chemistry and grafted polymer chain design have been shown to play an important role in determining the dispersion state of the grafted nanoparticles and hence the final optical properties of the nanocomposites. To prepare transparent epoxy nanocomposites, poly (glycidyl methacrylate) (PGMA) chains were grafted onto the optical nanoparticle surfaces via a combined phosphate ligand exchange process and azide-alkyne "click" chemistry. The dispersion behavior of PGMA-grafted nanoparticles within the epoxy matrix was investigated by systematically varying the grafting density and grafted chain length. It was found that within the small molecular weight epoxy resins, the dispersion states are more sensitive to the grafting density than the molecular weight of grafted chains. With high grafting densities

  15. [Chickenpox, burns and grafts].

    Science.gov (United States)

    Rojas Zegers, J; Fidel Avendaño, L

    1979-01-01

    An outbreak of chickenpox that occurred at the Burns Repair Surgery Unit, Department of Children's Surgery, Hospital R. del Río, between June and November, 1975, is reported. 27 cases of burned children were studied, including analysis of correlations of the stages and outcome of the disease (varicela), the trauma (burns) and the graft (repair surgery). As a result, the authors emphasize the following findings: 1. Burns and their repair are not aggravating factors for varicella. In a small number of cases the exanthema looked more confluent in the graft surgical areas and in the first degree burns healing spontaneously. 2. Usually there was an uneventful outcome of graft repair surgery on a varicella patient, either during the incubation period, the acme or the convalescence. 3. The fact that the outmost intensity of secondary viremia of varicella occurs before the onset of exanthemia, that is, during the late incubation period, is confirmed.

  16. Comparison of modified chandler, roller pump, and ball valve circulation models for in vitro testing in high blood flow conditions: application in thrombogenicity testing of different materials for vascular applications.

    Science.gov (United States)

    van Oeveren, Wim; Tielliu, Ignace F; de Hart, Jurgen

    2012-01-01

    Three different models, a modified Chandler loop, roller pump, and a new ball valve model (Hemobile), were compared with regard to intrinsic damage of blood components and activation of platelets. The Hemobile was used for testing of polymer tubes. High flow was not possible with the Chandler loop. The roller pump and the Hemobile could be adjusted to high flow, but he pump induced hemolysis. Platelet numbers were reduced in the roller pump and Chandler loop (P Dyneema Purity UHMWPE fiber and PET fiber based tubes, all showed hemolysis below 0.2% and reduced platelet count and function. Binding of fibrin and platelets was higer on PET, inflammatory markers were lowest on Dyneema Purity UHMWPE. We concluded that the Hemobile minimally affects blood and could be adjusted to high blood flows, simulating arterial shear stress. The Hemobile was used to measure hemocompatibility of graft material and showed Dyneema Purity UHMWPE fiber in many ways more hemocompatible than ePTFE and PET.

  17. Global DNA methylation changes in Cucurbitaceae inter-species grafting

    Directory of Open Access Journals (Sweden)

    Evangelia Avramidou

    2015-04-01

    Full Text Available Grafting has been used to improve yield, fruit quality and disease resistance in a range of tree and vegetable species. The molecular mechanisms underpinning grafting responses have only recently started to be delineated. One of those mechanisms involves long distance transfer of genetic material from rootstock to scion alluding to an epigenetic component to the grafting process. In the research presented herein we extended published work on heritable changes in the DNA methylation pattern of Solanaceae scion genomes, in Cucurbitaceae inter-species grafting. Specifically, we examined global DNA methylation changes in scions of cucumber, melon and watermelon heterografted onto pumpkin rootstocks using MSAP analysis. We observed a significant increase of global DNA methylation in cucumber and melon scions pointing to an epigenetic effect in Cucurbitaceae heterografting. Exploitation of differential epigenetic marking in different rootstock-scion combinations could lead to development of epi-molecular markers for generation and selection of superior quality grafted vegetables.

  18. Evaluation of alveolar grafting with tibial graft in adolescent patients

    Directory of Open Access Journals (Sweden)

    Sadique Hussain

    2013-01-01

    Conclusion: The tibial graft offers an excellent alternative to the conventional standard grafts such as iliac crest or rib grafts. The efficiency of the treatment measured at 6 months period on standard OPG or CT is comparable to the results obtained with the rib/iliac crest.

  19. Ru-dye grafted CdS and reduced graphene oxide Ru/CdS/rGO composite: An efficient and photo tuneable electrode material for solid state dye sensitized polymer solar cells.

    Science.gov (United States)

    Nosheen, Erum; Shah, Syed Mujtaba; Iqbal, Zafar

    2017-02-01

    This article provides a facile one step synthesis of CdS (cadmium sulphide) and CdS/rGO (reduced graphene oxide CdS nanocomposites) using DMF (N, N-Dimethyl formamide) both as a solvent and a reducing agent for the reduction of grapheme oxide. XRD (X-ray diffraction), FESEM (Field emission scanning electron microscopy), EDX (Elemental dispersive X-ray analysis), TEM (Transmission electron microscopy), UV-Vis (UV-visible) and Raman spectroscopy have been employed for the characterization of prepared samples. The prepared nano-composite was photosensitized with three well known Ru (Ruthenium) dyes i.e. N3 [cis-Bis(isothiocyanato) bis(2,2'-bipyridyl-4,4'-dicarboxylato ruthenium(II))], N719 [Di-tetrabutylammoniumcis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato) ruthenium (II)] and Z907 [cis-Bis(isothiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylato)(4,4'-di-nonyl-2'-bipyridyl)ruthenium(II)]. The effect of concentration and number of anchoring groups on the grafting was extensively studied in order to explore structure-activity relationship. Photosensitization of CdS/rGO nanocomposite was evidenced by UV-Visible, PL (Photoluminiscence), FT-IR (Fourier transform infra-red) spectroscopy and I-V (current-voltage measurements). The prepared samples were found as effective electrode materials for application in SSDSSCs (solid state dye sensitized solar cells) with a maximum output efficiency of 1.01% which is two times higher than the reference device under the same experimental conditions. The components of the synthesized nanohybrid material were found to be capable of providing a uni-directional and cascade path for the flow of electrons and holes in the desired directions. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Doppler US findings of vascular complication after liver transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Dong Jin; Kim, Pyo Nyun; Ha, Hyun Kwon; Lee, Mun Gyu; Auh, Yong Ho [College of Medicine, University of Ulsan, Ulsan (Korea, Republic of)

    2000-02-01

    Vascular complications after liver transplantation may involve the hepatic artery, and hepatic and portal veins. Arterial complications are common and significant vascular complications include thrombosis or stenosis, as well as pseudoaneurysms. Venous complications include thrombosis or stenosis of the inferior vena cana, or hepatic or portal vein. Since recent evidence has shown that emergent revascularization leads to improved graft salvage and patient survival with a relatively low rate of late biliary complications, accurate and prompt diagnosis of hepatic arterial complications is important. Doppler US is a relatively inexpensive, accurate, and non invasive method of diagnosing the vascular complications which may arise from liver transplantation. (author)

  1. The influence of rifamycin decontamination on incorporation of autologous onlay bone grafts in rats: A histometric and immunohistochemical evaluation.

    Science.gov (United States)

    Taşdemir, Ufuk; Özeç, İlker; Esen, Haci Hasan; Avunduk, M Cihat

    2015-05-01

    Although it has been shown that rifamycin is an effective agent for bone graft decontamination, no information exists on the effects of rifamycin decontamination on bone graft incorporation. The aim of this study was to evaluate the influence of rifamycin decontamination on the incorporation of autologous onlay bone grafts quantitatively. In 30 rats, a standardized 5.0-mm-diameter bone graft was harvested from the right mandibular angle, contaminated with saliva, decontaminated with rifamycin solution, and augmented to the left as an onlay graft. Ten animals were sacrificed at 7, 14, and 21 days after surgery. In the control group (10 rats), the onlay grafts were neither contaminated nor decontaminated, and the rats were sacrificed at 21 days after surgery. Histological slides were prepared from each grafted site for both immunohistochemistry analysis (bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) antibodies) and histometric analysis. Images obtained from the graft incorporation area with the light microscope were transferred to a PC, and they were evaluated using Clemex PE 3.5 image analysis software. The grafts were fully incorporated in all specimens. The results showed that rifamycin decontamination has no detrimental effect on graft incorporation and the findings revealed a tendency for earlier revascularization and osteogenesis in the decontamination group. Data were analyzed using variance analysis and Tukey's test. Rifamycin decontamination has no detrimental effect on autogenous graft incorporation, and it can be used for graft decontamination with confidence. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. In situ replacement of infected vascular prosthesis with fresh arterial homograft: Early and long-term results in 18 patients

    Directory of Open Access Journals (Sweden)

    Pejkić Siniša

    2013-01-01

    Full Text Available Introduction. Graft infection is rightly considered one of the severest complications of vascular reconstruction. Treatment is non­standardized and associated with high mortality and morbidity rates. The choice of therapeutic modality depends upon variety of factors. One increasingly used option is in situ replacement of the infected prosthesis with the arterial allograft. Objective. The aim of this prospective nonrandomized study was to evaluate the effectiveness and durability of fresh arterial allograft as in situ substitute for the infected vascular prosthesis. Methods. During period of 2002-2005, 18 patients with the synthetic vascular graft infection underwent partial or complete prosthesis removal and secondary in situ reconstruction using the fresh arterial allograft, preserved under hypothermic conditions in buffered saline solution with an addition of antibiotics. Results. In 14 male and 4 female patients, meanaged 62 years, 8 aortic and 10 peripheral arterial infected prostheses were partially or completely replaced with the allograft. Operative mortality was 27.8% and amputation rate was 22.2%. Systemic sepsis at initial presentation and highly virulent nature of causative microorganisms were identified as significant negative prognostic factors (χ² test, p<0.05. During the long­term follow­up (mean 47 months, allograft aneurysm developed in three patients, requiring allograft explantation, followed in two cases by tertiary prosthetic reconstruction. Conclusion. Substitution of the infected prosthesis with the arterial allograft could be successful if used selectively - for less virulent and localized infections of extracavitary grafts. Close follow­up is mandatory for timely diagnosis of late homograft lesions and its eventual replacement with more durable prosthetic material.

  3. Elastomeric degradable biomaterials by photopolymerization-based CAD-CAM for vascular tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Baudis, Stefan; Nehl, Franziska; Ligon, S Clark; Liska, Robert [Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163MC, A-1060 Vienna (Austria); Nigisch, Anneliese; Bernhard, David [Department of Surgery, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Bergmeister, Helga [Core Unit for Biomedical Research, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Stampfl, Juergen, E-mail: robert.liska@tuwien.ac.at [Institute of Material Science and Technology, Vienna University of Technology, Favoritenstrasse 9-11, A-1040 Vienna (Austria)

    2011-10-15

    A predominant portion of mortalities in industrial countries can be attributed to diseases of the cardiovascular system. In the last decades great efforts have been undertaken to develop materials for artificial vascular constructs. However, bio-inert materials like ePTFE or PET fail as material for narrow blood vessel replacements (coronary bypasses). Therefore, we aim to design new biocompatible materials to overcome this. In this paper we investigate the use of photoelastomers for artificial vascular constructs since they may be precisely structured by means of additive manufacturing technologies. Hence, 3D computer aided design and manufacturing technologies (CAD-CAM) offer the possibility of creating cellular structures within the grafts that might favour ingrowth of tissue. Different monomer formulations were screened concerning their suitability for this application but all had drawbacks, especially concerning the suture tear resistance. Therefore, we chose to modify the original network architecture by including dithiol chain transfer agents which effectively co-react with the acrylates and reduce crosslink density. A commercial urethane diacrylate was chosen as base monomer. In combination with reactive diluents and dithiols, the properties of the photopolymers could be tailored and degradability could be introduced. The optimized photoelastomers were in good mechanical accordance with native blood vessels, showed good biocompatibility in in vitro tests, degraded similar to poly(lactic acid) and were successfully manufactured with the 3D CAD-CAM technology.

  4. Face Graft Scaffold Production in a Rat Model.

    Science.gov (United States)

    Duisit, Jérôme; Amiel, Hadrien; Orlando, Giuseppe; Dedriche, Adeline; Behets, Catherine; Gianello, Pierre; Lengelé, Benoît

    2018-01-01

    As a route toward face bioengineering, the authors previously reported the production of a complete scaffold by perfusion-decellularization of a porcine ear subunit graft and partial recellularization. To extend the scaffold to the whole face and to down-scale it, they applied their findings to a rodent hemifacial graft model. After the animals were killed, seven full-thickness rat hemiface grafts were harvested with the common carotid artery and the external jugular vein as a pedicle, and cannulated. Grafts were decellularized by a detergent-based protocol: either by perfusion through the common carotid artery, or by mechanical agitation. After decellularization, samples were analyzed for DNA quantification and histology by hematoxylin and eosin, Masson trichrome, Sirius red, or Safranin O staining. Vascular tree patency was assessed by microangiographic computed tomography after contrast injection. Cell-friendly extracellular matrix was assessed by seeding of human adipose-derived stem cells and vital staining after 7 days of culture. Decellularization was effective in both groups, with a cell clearance at all levels, with the exception of cartilage areas in the agitation-treated groups. Microscopic assessment found a well-preserved extracellular matrix in both groups. Vascular contrast was found in all regions of the scaffolds. After the animals were killed, seeded cells were found viable and well distributed on all scaffolds. The authors successfully decellularized face grafts in a rodent model, with a preserved vascular tree. Perfusion-decellularization led to better and faster results compared with mechanical agitation but is not mandatory in this model. The rat face is an interesting scaffold model for further recellularization studies, in the final goal of human face bioengineering.

  5. Comparing the Effect of Human Wisdom Teeth Pulverized in Micron and Nano Particle Dimensions as Grafting Material in Healing of Tibial Bone Defect

    Directory of Open Access Journals (Sweden)

    Mostafa Govahi

    2016-11-01

    Full Text Available Background: In this article, we decided to introduce an available, affordable and biocompatible material from human teeth using nanotechnology to repair bone defects. Totally impacted wisdom teeth of human, which had been removed by surgery, were prepared as powder in two particle sizes of 500 micron and nano (up to 100 nm after sterilization. Method: Test cases were eight white rabbits of New Zealand species that were divided into 2 groups. Pores with 6 × 6 mm dimensions were created at hamstring area of tibia bone. In left leg tibia’s pore, nanoparticles powder and in the right leg tibia’s pore, micro particles powders were placed. The groups of two were sacrificed after 4, 8, 12 and 16 weeks. Samples underwent histomorphometric analysis and radiological analysis. The results showed the superiority of nano-groups in the percentage of new bone formation (26.62±10.88 over micro-groups (14.36±8.4 to (P-value = 0.015. Obtained Hounsfield number for micro-particle group was 2477±480 and for nanoparticle group was 1387±429 (p-value = 0.001. The differences in value soft bone vitality, inflammation, and foreign body reaction were not significant between the two groups of micro and nano. In micro particle group, despite suitable biocompatibility and Osseo integration, due to higher density and degree of crystalline, absorption and replacement rates by new bone and overall percentage of new bone formed were lower than nano group.

  6. Evaluation of hydroxyapatite (Periobone-G) as a bone graft material and calcium sulfate barrier (Capset) in treatment of interproximal vertical defects: A clinical and radiologic study

    Science.gov (United States)

    Gupta, Sanjay; Vandana, K. L.

    2013-01-01

    Background: This study has been undertaken to assess treatment response of interproximal vertical defects using an alloplast (Periobone-G) and calcium sulfate (Capset) as a barrier both clinically and radiographically. Materials and Methods: Eight patients were selected with 16 sites that were divided into control and experimental sites based on split mouth study design. Plaque index, gingival index, probing depth, clinical attachment level, gingival margin position were recorded at baseline and 9 months and radiographic assessment was done at baseline and 9 months after recording clinical parameters, the sites were randomly treated either with hydroxyapatite granules Periobone-G or hydroxyapatite granules (control group) was used to fill the osseous defect and calcium sulfate (Capset) (experiment group) barrier was placed. Result: The plaque score reduction was statistically highly significant within control and experimental groups. The gingival score reduction was significant within control and experimental groups, although there were no significant difference between the 2 groups. The pocket depth reduction was significant within control and experimental group, however, the hydroxyapatite + capset group showed significant reduction as compared with hydroxyapatite alone group. The clinical attachment gain and gingival margin position was significant within control and experimental groups, although there was no significant difference between the 2 groups. The amount of defect fill was significant in both control and experimental groups but the difference between the 2 groups was not significant. The mean change in alveolar crest level between control and experimental groups was significant (P=0.02). The percentage of original defect resolved was not significant. Conclusion: The use of calcium sulfate as a barrier proved its role in the treatment of interproximal defects. The application of calcium sulfate (Capset) barrier is easy and simple. The multifaceted

  7. Effectiveness of fibrin glue in adherence of skin graft

    Directory of Open Access Journals (Sweden)

    Konda Sireesha Reddy

    2017-01-01

    Full Text Available Background: Graft fixation is important for graft take. Fibrin glue has been proposed as an ideal material, because of its human origin and it provides firm adhesion in seconds or minutes. Objective: To evaluate the efficiency of fibrin glue, in increasing the take of skin graft. Assessment includes surgical time taken for graft fixation, haematoma/seroma formation, engraftment and wound closure by day 14. Methods: The study is an observational prospective study conducted in the Department of Plastic Surgery, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, from January 2016 to June 2016. Sixteen patients who underwent split skin grafting were assessed during the study period. Fibrin glue was used on the recipient bed before grafting. Results: Better haemostasis and graft adhesion, with a significant reduction of surgical time, were noted. Conclusion: The safety profile of fibrin glue was excellent as indicated by the lack of any related serious adverse experiences. These findings demonstrate that it is safe and effective for attachment of skin grafts, with outcomes at least as good as conventional methods.

  8. US and MRI of gastrointestinal graft-versus-host disease

    Energy Technology Data Exchange (ETDEWEB)

    Mentzel, Hans-Joachim; Vogt, Susanna; Behrendt, Werner; Kaiser, Werner A. [Institute for Diagnostic and Interventional Radiology, University of Jena (Germany); Kentouche, Karim; Gruhn, Bemd; Sauerbrey, Axel; Fuchs, Dietlinde; Zintl, Felix [Department of Paediatrics, University of Jena (Germany); Kosmehl, Hartwig [Department of Pathology, University of Jena (Germany)

    2002-03-01

    Abdominal problems often complicate the clinical course after bone marrow transplantation. Graft-versus-host disease occurs as a complication of allogenic bone marrow transplantation. In this report, the findings of intestinal involvement are described and correlated with histopathological findings. Increased bowel-wall thickness and increased vascularity were shown by US. MRI demonstrated generalised increased bowel-wall thickness associated with bowel-wall enhancement after administration of IV gadolinium. (orig.)

  9. Bone Graft Alternatives

    Science.gov (United States)

    ... created in or between the bones of the spine by disease, injury, deformity or during a surgical procedure such as spinal ... be used in surgical procedures to stabilize the spine after a fracture or to correct deformity. What are Bone Graft Substitutes? Since both allograft ...

  10. Artery Bypass Grafting

    African Journals Online (AJOL)

    Unknown

    nary artery disease (CAD) was coronary artery bypass graft (CAB G) using a segment of saphenous vein interposed between the ascend- ing aorta and the coronary artery distal to the obstructing lesion. This was performed by David Sabiston of Duke University in 1962. With the use of the recently developed technique of ...

  11. Artery Bypass Grafting

    African Journals Online (AJOL)

    development of CABG without CPB as occurring in three stages. Figure 1: The early stage: Grafts were limited to ... This interest led to the development of techniques such as mini- mally invasive direct coronary artery surgery (MIDCAB), surgery ... Diazepam 0.1 rng/kg P0. Cyclimorph 0.lmg/kg IMI on call to theatre. Theatre ...

  12. Acrylonitrile grafted to PVDF

    Science.gov (United States)

    Yang, Jin; Eitouni, Hany Basam

    2015-03-31

    PVDF-g-PAN has been synthesized by grafting polyacrylonitrile onto polyvinylidene fluoride using an ATRP/AGET method. The novel polymer is ionically conducive and has much more flexibility than PVDF alone, making it especially useful either as a binder in battery cell electrodes or as a polymer electrolyte in a battery cell.

  13. Fibular on-lay graft in the management of radial giant cell tumour--a case report.

    Science.gov (United States)

    Alonge, T O; Omololu, A B; Ogunlade, S O

    2001-01-01

    The management of bone loss following tumour resection poses a problem particularly in the upper limb where limb preservation is paramount. For bone loss less than 6cm, nonvascularized fibular graft has been advocated whereas in bone defects larger than this, vascularized fibular graft is the preferred option. In this case study, we have used a nonvascularized fibular on-lay graft (supplemented with cancellous bone graft) in the management of a distal radial bone loss of ten centimeters following resection of a giant cell tumour with remarkable success.

  14. Bone grafts using autogenous tooth blocks: a case series.

    Science.gov (United States)

    Kim, Young-Kyun; Kim, Su-Gwan; Um, In-Woong; Kim, Kyung-Wook

    2013-12-01

    A case study was conducted to examine the clinical results and histologic healing of bone grafts performed using an autogenous tooth block (AutoBT block), which was developed recently and proprietary. Guided bone regeneration, extraction socket graft, sinus bone graft, and ridge augmentation were performed using autogenous tooth block graft material in 12 patients from March 2009 to June 2010. The clinical outcomes of each case were examined, and tissue specimens were collected from 1 case 2.5 months after the bone graft for histopathological analysis. All of the cases had successful bone graft results. One patient developed wound dehiscence after surgery, although favorable secondary healing was achieved. One implant resulted in osseointegration failure. A histopathologic examination was performed after 2.5 months and showed excellent bone healing due to osteoconduction. The AutoBT block was incorporated into the upper soft tissue, aponeurosis, and lower recipient bone. There were no notable complications associated with the bone transplant materials. The AutoBT block is clinically useful for a variety of bone grafts.

  15. Radiographic and histological study of perennial bone defect repair in rat calvaria after treatment with blocks of porous bovine organic graft material Estudo radiográfico e histológico do reparo de defeito ósseo perene em calvária de rato após o tratamento com material de enxerto orgânico bovino poroso

    Directory of Open Access Journals (Sweden)

    Lucele Vieira Marins

    2004-03-01

    Full Text Available Over the last few years, various bone graft materials of bovine origin to be used in oromaxillofacial surgeries have entered the market. In the present study, we determined the capacity of a block organic bone graft material (Gen-ox, Baumer SA, Brazil prepared from bovine cancellous bone to promote the repair of critical size bone injuries in rat calvaria. A transosseous defect measuring approximately 8mm in diameter was performed with a surgical trephine in the parietal bone of 25 rats. In 15 animals, the defects were filled with a block of graft material measuring 8mm in diameter and soaked in the animal's own blood, and in the other 10 animals the defects were only filled with blood clots. The calvariae of rats receiving the material were collected 1, 3 and 6 months after surgery, and those of animals receiving the blood clots were collected immediately and 6 months after surgery. During surgery, the graft material was found to be of easy handling and to adapt perfectly to the receptor bed after soaking in blood. The results showed that, in most animals treated, the material was slowly resorbed and served as a space filling and maintenance material, favoring angiogenesis, cell migration and adhesion, and bone neoformation from the borders of the lesion. However, a foreign body-type granulomatous reaction, with the presence of numerous giant cells preventing local bone neoformation, was observed in two animals of the 1-month subgroup and in one animal of the 3-month subgroup. These cases were interpreted as resulting from the absence of demineralization and the lack of removal of potential antigen factors during production of the biomaterial. We conclude that, with improvement in the quality control of the material production, block organic bone matrix will become a good alternative for bone defect repair in the oromaxillofacial region due to its high osteoconductive capacity.Nos últimos anos, vários materiais de origem bovina para enxerto

  16. Fibrin sealant improves hemostasis in peripheral vascular surgery: a randomized prospective trial.

    Science.gov (United States)

    Schenk, Worthington G; Burks, Sandra G; Gagne, Paul J; Kagan, Steven A; Lawson, Jeffrey H; Spotnitz, William D

    2003-06-01

    To evaluate the efficacy and safety of an investigational fibrin sealant (FS) in a randomized prospective, partially blinded, controlled, multicenter trial. Upper extremity vascular access surgery using polytetrafluorethylene (PTFE) graft placement for dialysis was chosen as a reproducible, clinically relevant model for evaluating the usefulness of FS. The FS consisted of pooled human fibrinogen (60 mg/mL) and thrombin (500 NIH U/mL). Time to hemostasis was measured, and adverse events were monitored. Consenting adult patients (n = 48) undergoing placement of a standard PTFE graft were randomized in a 2:1:1 ratio to the treatment group using FS (ZLB Bioplasma AG, Bern, Switzerland), oxidized regenerated cellulose (Surgicel, Johnson & Johnson, New Brunswick, NJ), or pressure. Patients received heparin (3,000 IU IVP) before placement of vascular clamps. If the treatment was FS, clamps were left in place for 120 seconds after the application of study material to permit polymerization. If treatment was Surgicel, clamps were left in place until the agent had been applied according to manufacturer's instructions. If the treatment was pressure, clamps were released as soon as the investigator was ready to apply compression. Immediately after release of the last clamp, the arterial and venous suture lines were evaluated for bleeding. The time to hemostasis at both the venous and arterial sites was recorded. Significant (P < or =.005) reduction in time to hemostasis was achieved in the FS group. Thirteen (54.2%) patients randomized to FS experienced immediate hemostasis at both suture lines following clamp removal compared to no patients using Surgicel or pressure. Only one patient (7.1%) in the Surgicel group and no patients in the pressure group experienced hemostasis at 120 seconds from clamp removal, compared to 13 (54.2%) patients for FS. Adverse events were comparable in all groups. There were no seroconversions. FS achieved more rapid hemostasis than traditional

  17. Bone graft in the treatment of nonunion of the scaphoid with necrosis of the proximal pole: a literature review.

    Science.gov (United States)

    Severo, Antônio Lourenço; Lemos, Marcelo Barreto; Lech, Osvandré Luiz Canfield; Barreto Filho, Danilo; Strack, Daniel Paulo; Candido, Larissa Knapp

    2017-01-01

    Scaphoid fractures are the most common fractures of the carpal bones, corresponding to 60%. Of these, 10% progress to nonunion; moreover, 3% can present necrosis of the proximal pole. There are various methods of treatment using vascularized and non-vascularized bone grafts. To evaluate and compare the rate of scaphoid consolidation with necrosis of the proximal pole using different surgical techniques. The authors conducted a review of the literature using the following databases: PubMed and BIREME/LILACS, where 13 case series were selected (ten with use of vascularized bone grafts and three of non-vascularized bone grafts), according to inclusion and exclusion criteria. In most cases VBGs were used, especially those based on the 1,2 intercompartmental supraretinacular artery, due to greater reproducibility in performing the surgical technique.

  18. Vascular tumors of bone : Imaging findings

    NARCIS (Netherlands)

    Vermaat, Marieke; Vanel, Daniel; Kroon, Herman M.; Verbeke, Sofie L. J.; Alberghini, Marco; Bovee, Judith V. M. G.; Bloem, Johan L.

    Purpose: To identify radiological features of malignant vascular tumors of bone, which can be used to avoid erroneously diagnosing metastases based on radiological multifocality, and histological epitheloid phenotype. Materials and methods: From the databases of the Bologna & Netherlands Committee

  19. Role of adipose-derived stem cells in fat grafting and reconstructive surgery

    Directory of Open Access Journals (Sweden)

    Shaun S Tan

    2016-01-01

    Full Text Available Autologous fat grafting is commonly utilised to reconstruct soft tissue defects caused by ageing, trauma, chronic wounds and cancer resection. The benefits of fat grafting are minimal donor site morbidity and ease of availability through liposuction or lipectomy. Nonetheless, survival and longevity of fat grafts remain poor post-engraftment. Various methods to enhance fat graft survival are currently under investigation and its stem cell constituents are of particular interest. Cell-assisted lipotransfer refers to the addition of adipose-derived stem cell (ASC rich component of stromal vascular fraction to lipoaspirate, the results of which have proven promising. This article aims to review the role of ASCs in fat grafting and reconstructive surgery.

  20. Plant Vascular Biology 2013: vascular trafficking.

    Science.gov (United States)

    Ursache, Robertas; Heo, Jung-Ok; Helariutta, Ykä

    2014-04-01

    About 200 researchers from around the world attended the Third International Conference on Plant Vascular Biology (PVB 2013) held in July 2013 at the Rantapuisto Conference Center, in Helsinki, Finland (http://www.pvb2013.org). The plant vascular system, which connects every organ in the mature plant, continues to attract the interest of researchers representing a wide range of disciplines, including development, physiology, systems biology, and computational biology. At the meeting, participants discussed the latest research advances in vascular development, long- and short-distance vascular transport and long-distance signalling in plant defence, in addition to providing a context for how these studies intersect with each other. The meeting provided an opportunity for researchers working across a broad range of fields to share ideas and to discuss future directions in the expanding field of vascular biology. In this report, the latest advances in understanding the mechanism of vascular trafficking presented at the meeting have been summarized.

  1. Comb-like temperature-responsive polyhydroxyalkanoate-graft-poly(2-dimethylamino-ethylmethacrylate) for controllable protein adsorption

    DEFF Research Database (Denmark)

    Yao, Hui; Wei, Daixu; Che, Xuemei

    2016-01-01

    %. Graft copolymer PHA-g-PDMAEMA showed enhanced thermal stability, biocompatibility and controllable hydrophilicity compared with non-grafted P(3HDD-co-3H9D). The grafted material presented an obvious tendency of increasing protein adsorptions over the lower critical solution temperature (LCST 47.5 °C...... controllable protein adsorption for biomedical usages....

  2. Materialism.

    Science.gov (United States)

    Melnyk, Andrew

    2012-05-01

    Materialism is nearly universally assumed by cognitive scientists. Intuitively, materialism says that a person's mental states are nothing over and above his or her material states, while dualism denies this. Philosophers have introduced concepts (e.g., realization and supervenience) to assist in formulating the theses of materialism and dualism with more precision, and distinguished among importantly different versions of each view (e.g., eliminative materialism, substance dualism, and emergentism). They have also clarified the logic of arguments that use empirical findings to support materialism. Finally, they have devised various objections to materialism, objections that therefore serve also as arguments for dualism. These objections typically center around two features of mental states that materialism has had trouble in accommodating. The first feature is intentionality, the property of representing, or being about, objects, properties, and states of affairs external to the mental states. The second feature is phenomenal consciousness, the property possessed by many mental states of there being something it is like for the subject of the mental state to be in that mental state. WIREs Cogn Sci 2012, 3:281-292. doi: 10.1002/wcs.1174 For further resources related to this article, please visit the WIREs website. Copyright © 2012 John Wiley & Sons, Ltd.

  3. Influence of repeated aspiration on viability of fat grafts: a comparative study.

    Science.gov (United States)

    Wang, Rongrong; Sun, Jiaming; Xiong, Lingyun; Yang, Jie

    2015-11-01

    Fat grafting has been increasingly widely used in cosmetic and reconstructive surgery. However, the long-term retention of fat grafts is still unpredictable. Many critical variables have been found to significantly affect the viability of fat grafts; still, some of the ordinary impact factors are overlooked. We performed this study to find out whether repeated aspiration had an impact on fat grafts through an in vitro analysis and a nude mouse model. A 15 cm by 10 cm rectangle was marked at the lower abdomen. The cannula was gently advanced and retracted through the same incision in a fan fashion within the superficial layer to collect fat samples. Based on the sequence of harvesting, the collected adipose tissue was divided into five groups and labeled as syringes 1, 2, 3, 4, and 5. Part of the sample was dissociated and analyzed using cell staining, Cell Counting Kit-8 assay, and flow cytometry. The other part was injected in vivo and analyzed for weight and histology at varying time intervals. Fat grafts from the former syringes were presented with a greater number of viable adipocytes and a higher level of cellular function compared to the latter syringes. Additionally, fat grafts from former syringes had higher graft retention, better vascularity, and less cystic necrosis. Neither the viability of stromal vascular fractions (SVFs) nor the ratio of CD34 + CD45- cells within the SVFs were different among the five groups. Repeated aspiration had a negative impact on the adipocytes, but not on the SVFs. With an increasing time of aspiration, the viability of the adipocytes and long-term retention of fat grafts decreased gradually. Harvested fat grafts from the first few syringes may be more suitable for fat grafting. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

  4. Fetal origin of vascular aging

    Directory of Open Access Journals (Sweden)

    Shailesh Pitale

    2011-01-01

    Full Text Available Aging is increasingly regarded as an independent risk factor for development of cardiovascular diseases such as atherosclerosis and hypertension and their complications (e.g. MI and Stroke. It is well known that vascular disease evolve over decades with progressive accumulation of cellular and extracellular materials and many inflammatory processes. Metabolic syndrome, obesity and diabetes are conventionally recognized as risk factors for development of coronary vascular disease (CVD. These conditions are known to accelerate ageing process in general and vascular ageing in particular. Adverse events during intrauterine life may programme organ growth and favour disease later in life, popularly known as, ′Barker′s Hypothesis′. The notion of fetal programming implies that during critical periods of prenatal growth, changes in the hormonal and nutritional milieu of the conceptus may alter the full expression of the fetal genome, leading to permanent effects on a range of physiological.

  5. Bone graft complications: what can we do to prevent them?

    Science.gov (United States)

    Tandon, Rahul; Herford, Alan S.

    2014-03-01

    Introduction: Bone grafts are commonly used in oral and maxillofacial surgery, helping to restore missing bone structure and provide osseous support. In spite of their reported success, complications can and do arise. Examples include loosening and resorption of the graft, infection, and complete loss of the graft. These complications can potentially lead to larger defects, necessitating additional procedures to correct the problem. This not only causes great discomfort to the patient, but also drains considerable time and resources away from the clinician. Thus, improvements on identifying ways to identify and prevent these complications are constantly being sought. We have performed a literature review and identified several areas in the field of optics that could potentially help solve our problem. Optical Techniques: Raman spectroscopy has been shown to provide a transcutaneous measurement of bone mineral and matrix Raman bands. This could potentially provide surgeons with the ability to more accurately assess bone graft osseointegration. In-vivo near-infrared optical imaging could potentially provide accurate diagnosis of pathologic lesions such as osteosarcoma. Contrast-enhanced ultrasound could be used to detect vascular disturbances and other information related to the transplantation of osseous components. Conclusion: Bone graft complications can be one of the most devastating consequences of osseous surgery. As surgeons, we are constantly searching for ways to identify them earlier and prevent them. We hope that by presenting areas that could be used, we can gain a better insight to ways in which both fields can benefit.

  6. A multimodality vascular imaging phantom of an abdominal aortic aneurysm with a visible thrombus

    Energy Technology Data Exchange (ETDEWEB)

    Allard, Louise; Chayer, Boris; Qin Zhao [Laboratory of Biorheology and Medical Ultrasonics, Research Center, University of Montreal Hospital (CRCHUM), Quebec H2L 2W5 (Canada); Soulez, Gilles [Department of Radiology, University of Montreal Hospital (CHUM), Quebec H2L 2M1 (Canada); Department of Radiology, Radio-Oncology and Nuclear Medicine, University of Montreal, Quebec H3T 1J4 (Canada); Institute of Biomedical Engineering, University of Montreal, Quebec H3T 1J4 (Canada); Roy, David [Institute of Biomedical Engineering, University of Montreal, Quebec H3T 1J4 (Canada); Cloutier, Guy [Laboratory of Biorheology and Medical Ultrasonics, Research Center, University of Montreal Hospital (CRCHUM), Quebec H2L 2W5 (Canada); Department of Radiology, Radio-Oncology and Nuclear Medicine, University of Montreal, Quebec H3T 1J4 (Canada); Institute of Biomedical Engineering, University of Montreal, Quebec H3T 1J4 (Canada)

    2013-06-15

    Purpose: With the continuous development of new stent grafts and implantation techniques, it has now become technically feasible to treat abdominal aortic aneurysms (AAA) with challenging anatomy using endovascular repair with standard, fenestrated, or branched stent-grafts. In vitro experimentations are very useful to improve stent-graft design and conformability or imaging guidance for stent-graft delivery or follow-up. Vascular replicas also help to better understand the limitation of endovascular approaches in challenging anatomy and possibly improve surgical planning or training by practicing high risk clinical procedures in the laboratory to improve outcomes in the operating room. Most AAA phantoms available have a very basic anatomy, which is not representative of the clinical reality. This paper presents a method of fabrication of a realistic AAA phantom with a visible thrombus, as well as some mechanical properties characterizing such phantom. Methods: A realistic AAA geometry replica of a real patient anatomy taken from a multidetector computed tomography (CT) scan was manufactured. To demonstrate the multimodality imaging capability of this new phantom with a thrombus visible in magnetic resonance (MR) angiography, CT angiography (CTA), digital subtraction angiography (DSA), and ultrasound, image acquisitions with all these modalities were performed by using standard clinical protocols. Potential use of this phantom for stent deployment was also tested. A rheometer allowed defining hyperelastic and viscoelastic properties of phantom materials. Results: MR imaging measurements of SNR and CNR values on T1 and T2-weighted sequences and MR angiography indicated reasonable agreement with published values of AAA thrombus and abdominal components in vivo. X-ray absorption also lay within normal ranges of AAA patients and was representative of findings observed on CTA, fluoroscopy, and DSA. Ultrasound propagation speeds for developed materials were also in

  7. Electrospun vascular scaffold for cellularized small diameter blood vessels: A preclinical large animal study.

    Science.gov (United States)

    Ju, Young Min; Ahn, Hyunhee; Arenas-Herrera, Juan; Kim, Cheil; Abolbashari, Mehran; Atala, Anthony; Yoo, James J; Lee, Sang Jin

    2017-09-01

    The strategy of vascular tissue engineering is to create a vascular substitute by combining autologous vascular cells with a tubular-shaped biodegradable scaffold. We have previously developed a novel electrospun bilayered vascular scaffold that provides proper biological and biomechanical properties as well as structural configuration. In this study, we investigated the clinical feasibility of a cellularized vascular scaffold in a preclinical large animal model. We fabricated the cellularized vascular construct with autologous endothelial progenitor cell (EPC)-derived endothelial cells (ECs) and smooth muscle cells (SMCs) followed by a pulsatile bioreactor preconditioning. This fully cellularized vascular construct was tested in a sheep carotid arterial interposition model. After preconditioning, confluent and mature EC and SMC layers in the scaffold were achieved. The cellularized constructs sustained the structural integrity with a high degree of graft patency without eliciting an inflammatory response over the course of the 6-month period in sheep. Moreover, the matured EC coverage on the lumen and a thick smooth muscle layer were formed at 6months after transplantation. We demonstrated that electrospun bilayered vascular scaffolds in conjunction with autologous vascular cells may be a clinically applicable alternative to traditional prosthetic vascular graft substitutes. This study demonstrates the utility of tissue engineering to provide platform technologies for rehabilitation of patients recovering from severe, devastating cardiovascular diseases. The long-term goal is to provide alternatives to vascular grafting using bioengineered blood vessels derived from an autologous cell source with a functionalized vascular scaffold. This novel bilayered vascular construct for engineering blood vessels is designed to offer "off-the-shelf" availability for clinical translation. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  8. Bioabsorbable bypass grafts biofunctionalised with RGD have enhanced biophysical properties and endothelialisation tested in vivo

    Directory of Open Access Journals (Sweden)

    Larisa V Antonova

    2016-05-01

    Full Text Available Small diameter arterial bypass grafts are considered as unmet clinical need since the current grafts have poor patency of 25% within 5 years. We have developed a 3D scaffold manufactured from natural and synthetic biodegradable polymers, poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV and poly(ε-caprolactone (PCL, respectively. Further to improve the biophysical properties as well as endothelialisation, the grafts were covalently conjugated with arginine-glycine-aspartic acid (RGD bioactive peptides. The biophysical properties as well as endothelialisation of PHBV/PCL and PCL 2 mm diameter bypass grafts were assessed with and without biofunctionalisation with RGD peptides in vitro and in vivo. Morphology of the grafts was assessed by scanning electron microscopy, whereas physico-mechanical properties were evaluated using a physiological circulating system equipped with a state of art ultrasound vascular wall tracking system. Endothelialisation of the grafts in vitro and in vivo were assessed using a cell viability assay and rat abdominal aorta replacement model, respectively. The biofunctionalisation with RGD bioactive peptides decreased mean fiber diameter and mean pore area in PHBV/PCL grafts; however, this was not the case for PCL grafts. Both PHBV/PCL and PCL grafts with RGD peptides had lower durability compared to those without; these durability values were similar to those of internal mammary artery. Modification of PHBV/PCL and PCL grafts with RGD peptides increased endothelial cell viability in vitro by a factor of 8 and enhanced the formation of an endothelial cell monolayer in vivo one month postimplantation. In conclusion, PHBV/PCL small-caliber graft can be a suitable 3D scaffold for the development of a tissue engineering arterial bypass graft.

  9. Siloxane-grafted membranes

    Science.gov (United States)

    Friesen, Dwayne T.; Obligin, Alan S.

    1989-01-01

    Composite cellulosic semipermeable membranes are disclosed which are the covalently bonded reaction product of an asymmetric cellulosic semipermeable membrane and a polysiloxane containing reactive functional groups. The two reactants chemically bond by ether, ester, amide or acrylate linkages to form a siloxane-grafted cellulosic membrane having superior selectivity and flux stability. Selectivity may be enhanced by wetting the surface with a swelling agent such as water.

  10. A Review on the Modification of Polysaccharide Through Graft Copolymerization for Various Potential Applications

    Science.gov (United States)

    Kumar, Deepak; Pandey, Jyoti; Raj, Vinit; Kumar, Pramendra

    2017-01-01

    Introduction: Graft copolymerization is one of the most promising technique uses to modify the properties of naturally available polymers with a minimum loss in their native characteristics. Methods and Materials: Graft copolymerization is a very significant technique to add hybrid properties in backbone of polymers. The grafting generally initiated through the formation of free radical centers on the polymer backbone as well as monomer. Results: Grafted polysaccharides have various applications in different important scientific areas such as drug delivery, pharmaceutical field, plastic industry, waste water treatment, tannery effluent treatment, textile industry, agriculture area, etc. all of this fascinated us to summarize the major research articles over the last two decades outlining different methods of grafting, surface modification, graft copolymerization of synthetic and natural polymers. Conclusion: Various redox initiator systems viz. Ceric ammonium nitrate, per sulfate, Irradiation, FAS-H2O2 etc. is also explored for grafting of vinyl through conventional and non-conventional techniques. PMID:29151987

  11. Grafting of activated carbon cloths for selective adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Gineys, M.; Benoit, R.; Cohaut, N.; Béguin, F.; Delpeux-Ouldriane, S., E-mail: delpeux@cnrs-orleans.fr

    2016-05-01

    Graphical abstract: - Highlights: • A controlled grafting of carboxylic functions on activated carbon fibers. • The carbon material nanotextural properties preservation after grafting. • An identification of the grafting mechanism through ToF SIMS analysis. • A chemical mapping of the grafted surface using ToF SIMS technique and imaging. - Abstract: Chemical functionalization of an activated carbon cloth with 3-aminophthalic acid and 4-aminobenzoic acid groups by the in situ formation of the corresponding diazonium salt in aqueous acidic solution is reported. The nature and amount of selected functions on an activated carbon surface, in particular the grafted density, were determined by potentiometric titration, elemental analysis and X-ray photoelectron spectroscopy (XPS). The nanotextural properties of the modified carbon were explored by gas adsorption. Functionalized activated carbon cloth was obtained at a discrete grafting level while preserving interesting textural properties and a large porous volume. Finally, the grafting homogeneity of the carbon surface and the nature of the chemical bonding were investigated using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) technique.

  12. A Review on Grafting of Biofibers for Biocomposites.

    Science.gov (United States)

    Wei, Liqing; McDonald, Armando G

    2016-04-22

    A recent increase in the use of biofibers as low-cost and renewable reinforcement for the polymer biocomposites has been seen globally. Biofibers are classified into: lignocellulosic fibers ( i.e. , cellulose, wood and natural fibers), nanocellulose ( i.e. , cellulose nanocrystals and cellulose nanofibrils), and bacterial cellulose, while polymer matrix materials can be petroleum based or bio-based. Green biocomposites can be produced using both biobased fibers and polymers. Incompatibility between the hydrophilic biofibers and hydrophobic polymer matrix can cause performance failure of resulting biocomposites. Diverse efforts have focused on the modification of biofibers in order to improve the performances of biocomposites. "Grafting" copolymerization strategy can render the advantages of biofiber and impart polymer properties onto it and the performance of biocomposites can be tuned through changing grafting parameters. This review presents a short overview of various "grafting" methods which can be directly or potentially employed to enhance the interaction between biofibers and a polymer matrix for biocomposites. Major grafting techniques, including ring opening polymerization, grafting via coupling agent and free radical induced grafting, have been discussed. Improved properties such as mechanical, thermal, and water resistance have provided grafted biocomposites with new opportunities for applications in specific industries.

  13. Percutaneous treatment of complications occurring during hemodialysis graft recanalization

    Energy Technology Data Exchange (ETDEWEB)

    Sofocleous, Constantinos T. E-mail: constant@pol.net; Schur, Israel; Koh, Elsie; Hinrichs, Clay; Cooper, Stanley G.; Welber, Adam; Brountzos, Elias; Kelekis, Dimitris

    2003-09-01

    Introduction/objective: To describe and evaluate percutaneous treatment methods of complications occurring during recanalization of thrombosed hemodialysis access grafts. Methods and materials: A retrospective review of 579 thrombosed hemodialysis access grafts revealed 48 complications occurring during urokinase thrombolysis (512) or mechanical thrombectomy (67). These include 12 venous or venous anastomotic ruptures not controlled by balloon tamponade, eight arterial emboli, 12 graft extravasations, seven small hematomas, four intragraft pseudointimal 'dissections', two incidents of pulmonary edema, one episode of intestinal angina, one procedural death, and one distant hematoma. Results: Twelve cases of post angioplasty ruptures were treated with uncovered stents of which 10 resulted in graft salvage allowing successful hemodialysis. All arterial emboli were retrieved by Fogarty or embolectomy balloons. The 10/12 graft extravasations were successfully treated by digital compression while the procedure was completed and the graft flow was restored. Dissections were treated with prolonged Percutaneous Trasluminal Angioplasty (PTA) balloon inflation. Overall technical success was 39/48 (81%). Kaplan-Meier Primary and secondary patency rates were 72 and 78% at 30, 62 and 73% at 90 and 36 and 67% at 180 days, respectively. Secondary patency rates remained over 50% at 1 year. There were no additional complications caused by these maneuvers. Discussions and conclusion: The majority of complications occurring during percutaneous thrombolysis/thrombectomy of thrombosed access grafts, can be treated at the same sitting allowing completion of the recanalization procedure and usage of the same access for hemodialysis.

  14. SINGLE STAGE VENTRAL ONLAY BUCCAL MUCOSAL GRAFT URETHROPLASTY BASED ON TUNICA VAGINALIS FLAP FOR BALANITIS XEROTICA OBLITERANS RELATED URETHRAL MEATAL AND NAVICULAR FOSSA STRICTURES

    Directory of Open Access Journals (Sweden)

    Sathish Kumar G

    2017-07-01

    Full Text Available BACKGROUND Balanitis Xerotica Obliterans (BXO, also known as lichen sclerosus of penis is a chronic, progressive disease of the glans and prepuce that leads to phimosis and stricture of the urethra that can extend from the meatus and glanular urethra to the prostatic urethra. Urinary and sexual functions are affected and there is a severe reduction in quality of life. Many patients have been initially treated with tacrolimus or circumcision, when the disease has involved the prepuce and glans superficially, but conservative management has a limited role in this condition. Once stricture develops, surgical intervention in the form of grafts or flaps becomes necessary. We present our results with single-stage Ventral Onlay Buccal Mucosal Graft Urethroplasty (VOBMGU based on tunica vaginalis flap for BXO related strictures of meatus and fossa navicularis. MATERIALS AND METHODS From July 2014, six patients who underwent single stage Ventral Onlay Buccal Mucosal Graft Urethroplasty Graft (VOBMGU based on tunica vaginalis flap for BXO related strictures of urethral meatus and navicular fossa were included in the study. Patients presenting with BXO were clinically assessed for the extent of involvement as having BXO affecting the foreskin, glans, meatus, penile shaft, urethra and scrotum. They were radiologically assessed with a retrograde urethrogram and ultrasound abdomen. Outcome was assessed in terms of uroflowmetry, cosmetic appearance, stricture recurrence and complications. RESULTS Patients were reviewed every three months for over one year and six monthly. Only one patient had mild stenosis of the urethral meatus, as evidenced by change in flow, which was treated successfully with dilatation. One patient reported moderate splaying of urine, but this was mild in all other cases. All patients had a normal slit-like meatus, satisfactory voiding and sexual functions. CONCLUSION Isolated involvement of fossa navicularis and meatal stenosis stricture

  15. Collagen vascular disease

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/001223.htm Collagen vascular disease To use the sharing features on this page, ... previously said to have "connective tissue" or "collagen vascular" disease. We now have names for many specific conditions ...

  16. A Shape Memory Polymer Dialysis Needle Adapter for the Reduction of Hemodynamic Stress within Arteriovenous Grafts

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, J M; Small, W; Wilson, T S; Benett, W; Loge, J; Maitland, D J

    2006-08-16

    A deployable, shape memory polymer adapter is investigated for reducing the hemodynamic stress caused by a dialysis needle flow within an arteriovenous graft. Computational fluid dynamics simulations of dialysis sessions with and without the adapter demonstrate that the adapter provides a significant decrease in the wall shear stress. In vitro flow visualization measurements are made within a graft model following delivery and actuation of a prototype shape memory polymer adapter. Vascular access complications resulting from arteriovenous (AV) graft failures account for over $1 billion per year in the health care costs of dialysis patients in the U.S.[1] The primary mode of failure of arteriovenous fistulas (AVF's) and polytetrafluoroethylene (PTFE) grafts is the development of intimal hyperplasia (IH) and the subsequent formation of stenotic lesions, resulting in a graft flow decline. The hemodynamic stresses arising within AVF's and PTFE grafts play an important role in the pathogenesis of IH. Studies have shown that vascular damage can occur in regions where there is flow separation, oscillation, or extreme values of wall shear stress (WSS).[2] Nevaril et al.[3] show that exposure of red blood cells to WSS's on the order of 1500 dynes/cm2 can result in hemolysis. Hemodynamic stress from dialysis needle flow has recently been investigated for the role it plays in graft failure. Using laser Doppler velocimetry measurements, Unnikrishnan et al.[4] show that turbulence intensities are 5-6 times greater in the AV flow when the needle flow is present and that increased levels of turbulence exist for approximately 7-8cm downstream of the needle. Since the AVF or PTFE graft is exposed to these high levels of hemodynamic stress several hours each week during dialysis sessions, it is quite possible that needle flow is an important contributor to vascular access occlusion.[4] We present a method for reducing the hemodynamic stress in an AV graft by tailoring

  17. Effect of maxillary sinus floor augmentation without bone grafts

    Directory of Open Access Journals (Sweden)

    D Shiva Kumar

    2013-01-01

    Full Text Available Objective: The objective of the present review was to determine the effectiveness of maxillary sinus floor augmentation without bone grafts using lateral window technique. Materials and Methods: PubMed