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Sample records for synthetic vascular grafts

  1. 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.

  2. Engineered vascularized bone grafts

    OpenAIRE

    Tsigkou, Olga; Pomerantseva, Irina; Spencer, Joel A.; Redondo, Patricia A.; Hart, Alison R.; O’Doherty, Elisabeth; Lin, Yunfeng; Friedrich, Claudia C.; Daheron, Laurence; Lin, Charles P.; Sundback, Cathryn A.; Vacanti, Joseph P.; Neville, Craig

    2010-01-01

    Clinical protocols utilize bone marrow to seed synthetic and decellularized allogeneic bone grafts for enhancement of scaffold remodeling and fusion. Marrow-derived cytokines induce host neovascularization at the graft surface, but hypoxic conditions cause cell death at the core. Addition of cellular components that generate an extensive primitive plexus-like vascular network that would perfuse the entire scaffold upon anastomosis could potentially yield significantly higher-quality grafts. W...

  3. In vivo analysis of biocompatibility and vascularization of the synthetic bone grafting substitute NanoBone.

    Science.gov (United States)

    Abshagen, K; Schrodi, I; Gerber, T; Vollmar, B

    2009-11-01

    One of the major challenges in the application of bone substitutes is adequate vascularization and biocompatibility of the implant. Thus, the temporal course of neovascularization and the microvascular inflammatory response of implants of NanoBone (fully synthetic nanocrystalline bone grafting material) were studied in vivo by using the mouse dorsal skinfold chamber model. Angiogenesis, microhemodynamics, and leukocyte-endothelial cell interaction were analyzed repetitively after implantation in the center and in the border zone of the implant up to 15 days. Both NanoBone granules and plates exhibited high biocompatibility comparable to that of cancellous bone, as indicated by a lack of venular leukocyte activation after implantation. In both synthetic NanoBone groups, signs of angiogenesis could be observed even at day 5 after implantation, whereas granules showed higher functional vessel density compared with NanoBone plates. The angiogenic response of the cancellous bone was markedly accelerated in the center of the implant tissue. Histologically, implant tissue showed an ingrowth of vascularized fibrous tissue into the material combined with an increased number of foreign-body giant cells. In conclusion, NanoBone, particularly in granular form, showed high biocompatibility and high angiogenic response, thus improving the healing of bone defects. Our results underline that, beside the composition and nanostructure, the macrostructure is also of importance for the incorporation of the biomaterial by the host tissue. (c) 2008 Wiley Periodicals, Inc.

  4. Indium-111-labeled leukocyte scan in detection of synthetic vascular graft infection: The effect of antibiotic treatment

    International Nuclear Information System (INIS)

    Chung, C.J.; Hicklin, O.A.; Payan, J.M.; Gordon, L.

    1991-01-01

    To determine the sensitivity and specificity of the indium-111-( 111 In) labeled leukocyte scan for prosthetic vascular graft infection in patients treated with antibiotic therapy, a retrospective study was performed. Of 41 consecutive 111 In-labeled leukocyte scans performed to evaluate possible vascular graft infection, 23 scans were performed in patients treated with antibiotics. The average duration of antibiotic therapy was 21 days. Twelve positive and 11 negative scans for graft infection were found. By surgical and autopsy correlation of all positive cases, and clinical correlation (of all negative cases), there were 10 true-positive, 11 true-negative, 2 false-positive, and no false-negative scans for graft infections, for an overall sensitivity of 100% and specificity of 85%

  5. Vascularized osseous graft for scaphoid

    International Nuclear Information System (INIS)

    Mendez Daza, Carlos Hernan; Mathoulin, Cristophe

    2004-01-01

    The most commonly used technique for treatment of pseudo-arthrosis of the scaphoid is osteo-synthesis with Kirschnet wires and cortical sponge grafts. Results reported by different teams using this procedure show no more than 90% osseous consolidation, especially in cases where vascularisation of the proximal fragment of the scaphoid is compromised. Here we present a series of ten cases of pseudo-arthrosis of the scaphoid, treated using a new surgical technique involving a vascularized osseous graft of the distal radius. Using this procedure we obtained 100% consolidation, with no complications either during the procedure or immediately post-operatively. Patients returned to work in week 15 on average. In 4 cases we observed discomfort in the area of the scar, which was successfully treated using local cortisone injection. The results obtained are very similar to those seen in the literature on the different techniques for vascularized osseous grafts for pseudo-arthrosis of the scaphoid

  6. 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.

  7. 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.

  8. Calcification of a Synthetic Renovascular Graft in a Child

    Directory of Open Access Journals (Sweden)

    D.S.T. Chong

    Full Text Available : Introduction: Vascular grafts, especially in paediatric cases, need to be durable. Common failures such as thrombosis are well documented with research efforts directed towards them. However, there are lesser known causes of graft failure, such as graft calcification, and these also require further research focus. Report: A paediatric case is described in which a synthetic renovascular graft, implanted for mid-aortic syndrome, became calcified, necessitating surgical intervention to resolve graft malfunction. Significant calcification in the limb of a bifurcated polyethylene terephthalate graft was found to be the cause of resistant stenosis and refractory hypertension. Histology conducted on the explanted limb showed the presence of multinuclear giant cells, indicating a chronic foreign body response. Discussion: Calcification of vascular grafts is probably more common than previously recognised. Stenosis typically resistant to angioplasty may result in the long term and thus leading to surgical intervention. In young children, this is suboptimal as these grafts need to last throughout adulthood. Explanted prosthetic grafts should be sent to specialist registries such as that in Strasbourg to be optimally assessed so that contributory factors can be identified. Keywords: Renovascular graft, Paediatric, Calcification

  9. 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.

  10. [Localized purpura revealing vascular prosthetic graft infection].

    Science.gov (United States)

    Boureau, A S; Lescalie, F; Cassagnau, E; Clairand, R; Connault, J

    2013-07-01

    Prosthetic graft infection after vascular reconstruction is a rare but serious complication. We report a case of infection occurring late after implantation of an iliofemoral prosthetic vascular graft. The Staphylococcus aureus infection was revealed by vascular purpura localized on the right leg 7 years after implantation of a vascular prosthesis. This case illustrates an uncommonly late clinical manifestation presenting as an acute infection 7 years after the primary operation. In this situation, the presentation differs from early infection, which generally occurs within the first four postoperative months. Diagnosis and treatment remain a difficult challenge because prosthetic graft infection is a potentially life-threatening complication. Morbidity and mortality rates are high. Here we detail specific aspects of the clinical and radiological presentation. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  11. Early in-situ cellularization of a supramolecular vascular graft is modified by synthetic stromal cell-derived factor-1α derived peptides.

    Science.gov (United States)

    Muylaert, Dimitri E P; van Almen, Geert C; Talacua, Hanna; Fledderus, Joost O; Kluin, Jolanda; Hendrikse, Simone I S; van Dongen, Joost L J; Sijbesma, Eline; Bosman, Anton W; Mes, Tristan; Thakkar, Shraddha H; Smits, Anthal I P M; Bouten, Carlijn V C; Dankers, Patricia Y W; Verhaar, Marianne C

    2016-01-01

    In an in-situ approach towards tissue engineered cardiovascular replacement grafts, cell-free scaffolds are implanted that engage in endogenous tissue formation. Bioactive molecules can be incorporated into such grafts to facilitate cellular recruitment. Stromal cell derived factor 1α (SDF1α) is a powerful chemoattractant of lymphocytes, monocytes and progenitor cells and plays an important role in cellular signaling and tissue repair. Short SDF1α-peptides derived from its receptor-activating domain are capable of activating the SDF1α-specific receptor CXCR4. Here, we show that SDF1α-derived peptides can be chemically modified with a supramolecular four-fold hydrogen bonding ureido-pyrimidinone (UPy) moiety, that allows for the convenient incorporation of the UPy-SDF1α-derived peptides into a UPy-modified polymer scaffold. We hypothesized that a UPy-modified material bioactivated with these UPy-SDF1α-derived peptides can retain and stimulate circulating cells in an anti-inflammatory, pro-tissue formation signaling environment. First, the early recruitment of human peripheral blood mononuclear cells to the scaffolds was analyzed in vitro in a custom-made mesofluidic device applying physiological pulsatile fluid flow. Preferential adhesion of lymphocytes with reduced expression of inflammatory factors TNFα, MCP1 and lymphocyte activation marker CD25 was found in the bioactivated scaffolds, indicating a reduction in inflammatory signaling. As a proof of concept, in-vivo implantation of the bioactivated scaffolds as rat abdominal aorta interposition grafts showed increased cellularity by CD68+ cells after 7 days. These results indicate that a completely synthetic, cell-free biomaterial can attract and stimulate specific leukocyte populations through supramolecular incorporation of short bioactive SDF1α derived peptides. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. 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.

  13. VUV modification promotes endothelial cell proliferation on PTFE vascular grafts

    Science.gov (United States)

    Cezeaux, J. L.; Romoser, C. E.; Benson, R. S.; Buck, C. K.; Sackman, J. E.

    1998-05-01

    Small diameter (⩽6 mm ID ) synthetic vascular grafts, used as lower-limb vessel replacements in patients without suitable autologous saphenous veins, have a failure rate of 53% after 4 yr. Graft failure is due to thrombosis and intimal hyperplasia, an increase in smooth muscle cells in the lumen of the vessel which leads to progressive closing and ultimate occlusion of the vessel. In an effort to increase patency rates of synthetic grafts, investigators have seeded vascular grafts with endothelial cells prior to implantation in an attempt to control both thrombosis and smooth muscle proliferation. This technique has been successful for the development of an endothelial monolayer in animal trials, but has met with limited success in humans. The hydrophobicity, low surface energy, and weak electrical charge of expanded polytetrafluoroethylene (ePTFE) provides conditions which are not optimal for endothelial cell attachment. The purpose of this study is to evaluate the effect of vacuum ultraviolet (VUV) modification of ePTFE on endothelial cell adhesion and proliferation. Pieces of ePTFE graft material were exposed to 10, 20 or 40 W VUV radiation for 10, 20 or 40 min using a UV excimer lamp. Prior to cell adhesion and proliferation experiments, the grafts pieces were autoclaved and cut into pledgets. Half of the pledgets were precoated with fibronectin ( 20 μg/ml). Cell adhesion was measured by seeding 3H-thymidine labeled human umbilical vein endothelial cells (HUVEC) onto the pledgets for 60 min. The pledgets were then washed and the remaining radioactivity assayed using scintillation counting. For the cell proliferation experiments, pledgets were seeded with unlabeled HUVEC which were allowed to adhere to the graft material for 18 h. The cells were then exposed to 3H-thymidine ( 1 μCi/ml) for approximately 48 h and then washed to remove any unincorporated 3H-thymidine. Incorporation of 3H-thymidine was measured using scintillation counting. Four replicate

  14. Early in-situ cellularization of a supramolecular vascular graft is modified by synthetic stromal cell-derived factor-1α derived peptides

    NARCIS (Netherlands)

    Muylaert, Dimitri E. P.; van Almen, Geert C.; Talacua, Hanna; Fledderus, Joost O.; Kluin, Jolanda; Hendrikse, Simone I. S.; van Dongen, Joost L. J.; Sijbesma, Eline; Bosman, Anton W.; Mes, Tristan; Thakkar, Shraddha H.; Smits, Anthal I. P. M.; Bouten, Carlijn V. C.; Dankers, Patricia Y. W.; Verhaar, Marianne C.

    2016-01-01

    In an in-situ approach towards tissue engineered cardiovascular replacement grafts, cell-free scaffolds are implanted that engage in endogenous tissue formation. Bioactive molecules can be incorporated into such grafts to facilitate cellular recruitment. Stromal cell derived factor 1α (SDF1α) is a

  15. Early in-situ cellularization of a supramolecular vascular graft is modified by synthetic stromal cell-derived factor-1α derived peptides

    NARCIS (Netherlands)

    Muylaert, Dimitri E P; van Almen, Geert C; Talacua, Hanna; Fledderus, Joost O; Kluin, Jolanda; Hendrikse, Simone I S; van Dongen, Joost L J; Sijbesma, Eline; Bosman, Anton W; Mes, Tristan; Thakkar, Shraddha H; Smits, Anthal I P M; Bouten, Carlijn V C; Dankers, Patricia Y W; Verhaar, Marianne C

    In an in-situ approach towards tissue engineered cardiovascular replacement grafts, cell-free scaffolds are implanted that engage in endogenous tissue formation. Bioactive molecules can be incorporated into such grafts to facilitate cellular recruitment. Stromal cell derived factor 1α (SDF1α) is a

  16. Vascularized nerve grafts: an experimental study.

    Science.gov (United States)

    Donzelli, Renato; Capone, Crescenzo; Sgulò, Francesco Giovanni; Mariniello, Giuseppe; Maiuri, Francesco

    2016-08-01

    The aim of this study is to define an experimental model in order to promote the functional recovery of the nerves using grafts with vascular support (Vascular Nerve Grafts - VNG). The aim of this study is to define, on an experimental model in normal recipient bed, whether the functional recovery with VNG is superior to that obtained non-vascularized graft (NNG). Twenty male rabbits, which underwent dissection of sciatic nerve, were later treated by reinnervation through an autograft. In 10 animals the reconstruction of sciatic nerve was realized with VNG; in 10 control animals the reconstruction of sciatic nerve was realized with NNG. The VNG group showed a better axonal organization and a significantly higher number of regenerated axons in the early phases (after 30 days) than the NNG group, whereas the difference in the axonal number at day 90 was less significant; besides, the axon diameter and the myelin thickness were not significantly improved by VNG group. Our data suggests that the use of VNG leads to a faster regeneration process and a better functional recovery, although the final results are comparable to those of the NNG. VNG improve the quality of the axonal regeneration (axonal diameter and Schwann cells), although the increase in the axonal number is not significant and does not improve the long-term functional outcome.

  17. 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

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

    International Nuclear Information System (INIS)

    Tan, Zhikai; Wang, Hongjie; Gao, Xiangkai; Liu, Tong; Tan, Yongjun

    2016-01-01

    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

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

    Science.gov (United States)

    Tan, Zhikai; Wang, Hongjie; Gao, Xiangkai; Liu, Tong; Tan, Yongjun

    2016-10-01

    There is an increasing demand for functional small-diameter vascular grafts (diameterElectrospinning 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Fixation of tibial plateau fractures with synthetic bone graft versus natural bone graft: a comparison study.

    LENUS (Irish Health Repository)

    Ong, J C Y

    2012-06-01

    The goal of this study was to determine differences in fracture stability and functional outcome between synthetic bone graft and natural bone graft with internal fixation of tibia plateau metaphyseal defects.

  1. 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... prosthesis. (a) Identification. A vascular graft prosthesis is an implanted device intended to repair... Prostheses 510(k) Submissions.” [66 FR 18542, Apr. 10, 2001] ...

  2. [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.

  3. In vitro and ex vivo hemocompatibility of off-the-shelf modified poly(vinyl alcohol) vascular grafts

    OpenAIRE

    Cutiongco, Marie Francene A.; Anderson, Deirdre E. J.; Hinds, Monica T.; Yim, Evelyn K. F.

    2015-01-01

    Synthetic small diameter vascular grafts with mechanical properties of native arteries, resistance to thrombosis and capacity to stimulate in situ endothelialization are an unmet clinical need. Poly(vinyl alcohol) hydrogel (PVA) is an excellent candidate as a vascular graft due to its tunable mechanical properties. However, the hydrophilicity and bio-inertness of PVA prevents endothelialization in vivo. We hypothesize that the modification of PVA with biomolecules and topographies creates a h...

  4. Coaxial electrospinning multicomponent functional controlled-release vascular graft: Optimization of graft properties.

    Science.gov (United States)

    Yin, Anlin; Luo, Rifang; Li, Jiukai; Mo, Xiumei; Wang, Yunbing; Zhang, Xingdong

    2017-04-01

    Small diameter vascular grafts possessing desirable biocompatibility and suitable mechanical properties have become an urgent clinic demand. Herein, heparin loaded fibrous grafts of collagen/chitosan/poly(l-lactic acid-co-ε-caprolactone) (PLCL) were successfully fabricated via coaxial electrospinning. By controlling the concentration of heparin and the ratio of collagen/chitosan/PLCL, most grafts had the heparin encapsulation efficiency higher than 70%, and the heparin presented sustained release for more than 45 days. Particularly, such multicomponent grafts had relative low initial burst release, and after heparin releasing for 3 weeks, the grafts still showed good anti-platelet adhesion ability. In addition, along with the excellent cell biocompatibility, the fabricated grafts possessed suitable mechanical properties including good tensile strength, suture retention strength, burst pressure and compliance which could well match the native blood vessels. Thus, the optimized graft properties could be properly addressed for vascular tissue application via coaxial electrospinning. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. PPS-PEG surface coating to reduce thrombogenicity of small diameter ePTFE vascular grafts.

    Science.gov (United States)

    Karrer, L; Duwe, J; Zisch, A H; Khabiri, E; Cikirikcioglu, M; Napoli, A; Goessl, A; Schaffner, T; Hess, O M; Carrel, T; Kalangos, A; Hubbell, J A; Walpoth, B H

    2005-10-01

    Patency failure of small vascular synthetic grafts is still a major problem for coronary and peripheral revascularization. Thus, three new surface coatings of small synthetic grafts were tested in an acute pig model to evaluate their thrombogenicity (extracorporeal arterio-venous shunt) and in a chronic rat model to evaluate the tissue reaction they induced (subcutaneous implantation). In five domestic pigs (25-30 kg) an extracorporeal femoro-femoral arterio-venous shunt model was used. The study protocol included first a non-heparinized perfusion sequence followed by graft perfusion after 10,000 UI iv heparin. Grafts were perfused for 3 and 9 minutes. The following coatings were tested on ePTFE grafts: poly-propylene sulphide (PPS)--poly-ethylene glycol (PEG) (wet and dry applications) as well as carbon. Two sets of control were used, one dry and one wet (vehicle only). After perfusion grafts were examined by scanning electron microscopy for semi-quantitative assessment (score 0-3) of cellular and microthrombi deposition. To assess tissue compatibility, pieces of each material were implanted subcutaneously in 16 Wistar rats. At 2, 4, 8, 12 weeks four animals each were sacrificed for semi-quantitative (score 0-3) histologic evaluation of tissue reaction. In the pig model, cellular deposition and microthrombi formation increased over time. In non- heparinized animals, the coatings did not improve the surface characteristics, since they did not prevent microthrombi formation and cellular deposition. In heparinized animals, thrombogenicity was lowest in coated grafts,especially in PPS -PEG dry (pPPS-PEG dry, but this difference was not statistically significant vs.controls. In the rat model,no significant differences of the tissue reaction could be shown between materials. While all coatings failed to add any benefit for lowering tissue reaction, surface coating with PPS -PEG (dry application) reduced thrombogenicity significantly (in heparinized animals) and thus

  6. Composite vascular repair grafts via micro-imprinting and electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yuanyuan, E-mail: yuanyuan-liu@shu.edu.cn; Hu, Qingxi, E-mail: huqingxi@shu.edu.cn [Rapid Manufacturing Engineering Center, Shanghai University, Shanghai 200444 (China); Shanghai Key Laboratory of Intelligent Manufacturing and Robotics, Shanghai 200072 (China); Xiang, Ke, E-mail: xiangke@shu.edu.cn; Chen, Haiping, E-mail: 519673062@qq.com; Li, Yu, E-mail: liyu@hpu.edu.cn [Rapid Manufacturing Engineering Center, Shanghai University, Shanghai 200444 (China)

    2015-04-15

    Composite vascular grafts formed by micro-imprinting and electrospinning exhibited improved mechanical properties relative to those formed by electrospinning alone. The three-layered composite grafts mimic the three-layered structure of natural blood vessels. The middle layer is made by micro-imprinting poly-p-dioxanone (PPDO), while the inner and outer layers are electrospun mixtures of chitosan and polyvinyl alcohol. The graft morphology is characterized with scanning electron microscopy. For constant graft thicknesses, the PPDO increases the mechanical strength. Cells cultivated on the vascular grafts adhere and proliferate better because of the natural, biological chitosan in the inner and outer layers. Overall, the composite scaffolds could be good candidates for blood vessel repair.

  7. 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.

  8. 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

  9. Ga-67 citrate scan in vascular graft infection

    Energy Technology Data Exchange (ETDEWEB)

    Banzo, I.; Quirce, R.; Serrano, J.; Jimenez, J.; Tabuenca, O.; Carril, J.M. (Hospital Universitario Valdecilla, Santander (Spain))

    1992-11-01

    The clinical utility of the Ga-67 scan has been studied in 9 patients with clinical suspicion of vascular graft infection. Eleven grafts were analyzed: 4 aortobifemoral, 2 iliofemoral, 3 femoropopliteal, 1 axillofemoral, and 1 axillobifemoral. The Ga-67 scan was positive in 8 grafts with bacteriological proof of infection and negative in 3 grafts in which infection was ruled out by clinical follow-up. A Ga-67 scan also demonstrated the spread of infection to the thigh in two patients and to the pelvis in another two patients. In 4 patients CT was performed. The CT findings included graft thrombosis, perigraft fluid collection and thickened graft wall. No discrepancies were found between the CT scan and Ga-67 scan. In three patients a control Ga-67 scan was carried out after specific antibiotic and surgical treatment. Two of these showed increased Ga-67 uptake and spreading of infection along the graft; in the other patient, a Ga-67 scan revealed normalization after resolution of an abdominal abscess. In conclusion, the Ga-67 scan proved useful in the diagnosis of vascular graft infection, the definition of location of the extent of the disease and in the evaluation of the efficiency of treatment. (author).

  10. 18F-FDG uptake in noninfected prosthetic vascular grafts: incidence, patterns, and changes over time.

    Science.gov (United States)

    Keidar, Zohar; Pirmisashvili, Natalia; Leiderman, Max; Nitecki, Samy; Israel, Ora

    2014-03-01

    (18)F-FDG PET/CT is of value in the diagnosis of prosthetic vascular graft infection, but potential pitfalls related to tracer uptake in noninfected implants have been described. The current study assesses the incidence and patterns of (18)F-FDG uptake over time in noninfected grafts, in relationship to prosthetic material and location. A 12-y PET/CT database was retrospectively searched for cancer patients with prosthetic vascular grafts. Data retrieved from patient files included graft location, material, and time from surgery. Images were reviewed by 2 nuclear medicine physicians in consensus, with the presence and patterns (focal, diffuse homogeneous, inhomogeneous) of increased (18)F-FDG uptake in grafts recorded. The mean standardized uptake value in grafts (SUV-G) and mediastinum (SUV-M) was measured. The ratio of SUV-G to SUV-M (SUV-G/SUV-M) was calculated for each graft. One hundred seven prostheses were identified in 102 studies in 43 cancer patients. Sixty-seven prostheses were made of Dacron, 33 of Gore-Tex, and 7 were native veins. No increased (18)F-FDG uptake was found in 9 grafts (native veins, 4; Gore-Tex, 3; Dacron, 2). There was diffuse homogeneous uptake in 68 and inhomogeneous uptake in 30 grafts. The homogeneous pattern was more prevalent in Gore-Tex whereas the inhomogeneous uptake was seen more in Dacron vascular grafts. None of the grafts demonstrated focal uptake. The SUV-G range was 0.4-6.3 (average, 1.9), and SUV-M range was 0.6-2.4 (average, 1.4). The intensity of uptake was significantly higher in Dacron (SUV-G = 2.35 and SUV-G/SUV-M = 1.72) than in Gore-Tex (SUV-G = 1.09, SUV-G/SUV-M = 0.91) and native vein grafts (SUV-G = 1.07, SUV-G/SUV-M = 0.75) (P < 0.005). Native vein grafts showed a significant decrease in (18)F-FDG uptake over time whereas synthetic grafts showed no change in intensity for a follow-up of up to 16 y. Diffuse (18)F-FDG uptake was found in 92% of noninfected vascular prostheses, more in Dacron grafts than with

  11. Toward a patient-specific tissue engineered vascular graft.

    Science.gov (United States)

    Best, Cameron; Strouse, Robert; Hor, Kan; Pepper, Victoria; Tipton, Amy; Kelly, John; Shinoka, Toshiharu; Breuer, Christopher

    2018-01-01

    Integrating three-dimensional printing with the creation of tissue-engineered vascular grafts could provide a readily available, patient-specific, autologous tissue source that could significantly improve outcomes in newborns with congenital heart disease. Here, we present the recent case of a candidate for our tissue-engineered vascular graft clinical trial deemed ineligible due to complex anatomical requirements and consider the application of three-dimensional printing technologies for a patient-specific graft. We 3D-printed a closed-disposable seeding device and validated that it performed equivalently to the traditional open seeding technique using ovine bone marrow-derived mononuclear cells. Next, our candidate's preoperative imaging was reviewed to propose a patient-specific graft. A seeding apparatus was then designed to accommodate the custom graft and 3D-printed on a commodity fused deposition modeler. This exploratory feasibility study represents an important proof of concept advancing progress toward a rationally designed patient-specific tissue-engineered vascular graft for clinical application.

  12. Vascular Reconstruction Technique Using a Tubular Graft for Leiomyosarcoma of the Inferior Vena Cava: A Case Report

    Directory of Open Access Journals (Sweden)

    C. Higutchi

    Full Text Available Objective/background: This study is a case report that addresses the key aspects of vascular reconstruction, as well as the intraoperative complications, postoperative morbidity, and possibility of adjunctive therapy. Methods: This article reports the case of a 46 year old female patient with a leiomyosarcoma located in the middle segment of the inferior vena cava (between the renal and hepatic veins who underwent surgical resection with vena cava reconstruction and insertion of a tubular graft made of a synthetic material. Results: This case report reveals that surgical resection of the tumor with the insertion of a smaller-caliber tubular graft provide better patency of the vena cava reconstruction, which was maintained for a year after surgery. In addition, the patient was asymptomatic for lower limb edema, despite having a local recurrence after one year. Surgical resection is the treatment of choice for leiomyosarcoma of the inferior vena cava (LIVC and is the only therapy that offers a chance of cure. Several surgical techniques are used for this condition, especially, reconstruction with a vascular graft using natural or synthetic materials. Conclusion: Due to the aggressiveness of the disease, this study suggests that surgical intervention used may have no influence on a patient's survival outcome. However, vascular reconstruction with a smaller-caliber tubular graft may yield a better prognosis for patients in terms of postoperative symptoms, such as edema and thrombosis. Keywords: Inferior vena cava, Leiomyosarcoma, Synthetic vascular grafting

  13. Modification of synthetic fibers by radiation-induced grafting

    International Nuclear Information System (INIS)

    Kaji, Kanako

    1981-05-01

    The present report describes studies to modify properties of synthetic fibers by radiation-induced grafting technique. This technique was employed since it is considered to be generally applicable to the grafting of a radically polymerizable monomer onto fiber. Three synthetic fibers were used mainly in the present studies; (1) polyester fiber which is ranked as the first in the amount of production in the synthetic fibers at present and is expected to increase in its importance in the future, (2) poly (vinyl chloride) fiber which is inexpensive and fire-retardant, and (3) polyethylene fiber which is not yet used in apparel at present. In order to perform the grafting, the following two methods were studied; one is to graft monomer uniformly in the fiber preventing homopolymerization of the monomer outside of the fiber, and the other to graft monomer only on the fiber surface. Using these methods, the following experiments were carried out and fairly good results as expected were obtained. (1) In the case of polyester fiber it was intended to make this more hydrophilic and fire-retardant. (2) Concerning to poly(vinyl chloride) fiber experiments were carried out to make the fiber more hydrophilic and simultaneously more heat-resistant. (3) In the case of polyethylene fiber, target was fire-retardance and heat-resistance. (author)

  14. Vascularized bone grafting in a canine carpal avascular necrosis model

    NARCIS (Netherlands)

    Willems, Wouter F.; Alberton, Gregory M.; Bishop, Allen T.; Kremer, Thomas

    2011-01-01

    Limited experimental research has been performed on the treatment of avascular necrosis (AVN) by vascularized bone grafting. A new model simulating carpal AVN was created to investigate surgical revascularization of necrotic bone. In seven mongrel dogs, AVN was induced by removal of the radial

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Vascularized nerve grafts for lower extremity nerve reconstruction.

    Science.gov (United States)

    Terzis, Julia K; Kostopoulos, Vasileios K

    2010-02-01

    Vascularized nerve grafts (VNG) were introduced in 1976 but since then, there have been no reports of their usage in lower extremity reconstruction systematically. The factors influencing outcomes as well as a comparison with conventional nerve grafts will be presented.Since 1981, 14 lower extremity nerve injuries in 12 patients have been reconstructed with VNG. Common peroneal nerve was injured in 12 and posterior tibial nerve in 5 patients. The level of the injury was at the knee or thigh. Twelve sural nerves were used as VNG with or without concomitant vascularized posterior calf fascia.All patients regained improved sensibility and adequate posterior tibial nerve function. For common peroneal nerve reconstructions, all patients with denervation time less than 6 months regained muscle strength of grade at least 4, even when long grafts were used for defects of 20 cm or more. Late cases, yielded inadequate muscle function even with the use of VNG.Denervation time of 6 months or less was critical for reconstruction with vascularized nerve graft. Not only the results were statistically significant compared with late cases, but also all early operated patients achieved excellent results. VNG are strongly recommended in traction avulsion injuries of the lower extremity with lengthy nerve damage.

  17. Engineering Vascularized Bone Grafts by Integrating a Biomimetic Periosteum and β-TCP Scaffold

    Science.gov (United States)

    2015-01-01

    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. PMID:24858072

  18. Design of biomimetic vascular grafts with magnetic endothelial patterning.

    Science.gov (United States)

    Fayol, Delphine; Le Visage, Catherine; Ino, Julia; Gazeau, Florence; Letourneur, Didier; Wilhelm, Claire

    2013-01-01

    The development of small diameter vascular grafts with a controlled pluricellular organization is still needed for effective vascular tissue engineering. Here, we describe a technological approach combining a tubular scaffold and magnetically labeled cells to create a pluricellular and organized vascular graft, the endothelialization of which could be monitored by MRI prior to transplantation. A novel type of scaffold was developed with a tubular geometry and a porous bulk structure enabling the seeding of cells in the scaffold pores. A homogeneous distribution of human mesenchymal stem cells in the macroporous structure was obtained by seeding the freeze-dried scaffold with the cell suspension. The efficient covering of the luminal surface of the tube was then made possible thanks to the implementation of a magnetic-based patterning technique. Human endothelial cells or endothelial progenitors were magnetically labeled with iron oxide nanoparticles and successfully attracted to the 2-mm lumen where they attached and formed a continuous endothelium. The combination of imaging modalities [fluorescence imaging, histology, and 3D magnetic resonance imaging (MRI)] evidenced the integrity of the vascular construct. In particular, the observation of different cell organizations in a vascular scaffold within the range of resolution of single cells by 4.7 T MRI is reported.

  19. Blood Vessel-Derived Acellular Matrix for Vascular Graft Application

    Directory of Open Access Journals (Sweden)

    Luigi Dall’Olmo

    2014-01-01

    Full Text Available To overcome the issues connected to the use of autologous vascular grafts and artificial materials for reconstruction of small diameter (<6 mm blood vessels, this study aimed to develop acellular matrix- (AM- based vascular grafts. Rat iliac arteries were decellularized by a detergent-enzymatic treatment, whereas endothelial cells (ECs were obtained through enzymatic digestion of rat skin followed by immunomagnetic separation of CD31-positive cells. Sixteen female Lewis rats (8 weeks old received only AM or previously in vitro reendothelialized AM as abdominal aorta interposition grafts (about 1 cm. The detergent-enzymatic treatment completely removed the cellular part of vessels and both MHC class I and class II antigens. One month after surgery, the luminal surface of implanted AMs was partially covered by ECs and several platelets adhered in the areas lacking cell coverage. Intimal hyperplasia, already detected after 1 month, increased at 3 months. On the contrary, all grafts composed by AM and ECs were completely covered at 1 month and their structure was similar to that of native vessels at 3 months. Taken together, our findings show that prostheses composed of AM preseeded with ECs could be a promising approach for the replacement of blood vessels.

  20. Renal vessel reconstruction in kidney transplantation using a polytetrafluoroethylene (PTFE) vascular graft.

    Science.gov (United States)

    Kamel, Mohamed H; Thomas, Anil A; Mohan, Ponnusamy; Hickey, David P

    2007-04-01

    We report a rare experience in reconstructing short renal vessels in kidney transplantation using polytetrafluroethylene (PTFE) vascular grafts. The short renal vessels in three kidney grafts were managed by the interposition of PTFE vascular grafts. Two grafts were from deceased donors and the third was a renal auto-transplant graft. PTFE grafts were used to lengthen short renal veins in two kidney grafts and a short renal artery in one. The warm ischaemia time was under 1 h and all kidneys functioned well post-operatively. Excellent blood perfusion in the three renal grafts was present on postoperative MAG 3 renal scan. No intra-operative or post-operative complications were encountered. In the three described patients, the use of PTFE vascular graft presented no additional morbidity to the kidney transplant operation and no post-oerative complication was related to its use. However, more data are necessary to conclude that PTFE graft can be used safely in kidney transplantation.

  1. Vascularized pedicle bone grafting for nonunions of the tarsal navicular.

    Science.gov (United States)

    Fishman, Felicity G; Adams, Samuel B; Easley, Mark E; Nunley, James A

    2012-09-01

    Osteonecrosis and nonunions of the tarsal navicular remain a challenging clinical problem. This article presents a series of patients treated with local vascularized pedicle bone grafting to the navicular. The purpose of this study was to determine the early clinical and radiographic outcomes of this technique. Patients who underwent local vascularized pedicle bone grafting for osteonecrosis of the navicular from 2002 to 2007 were included in this study. The Ankle Osteoarthritis Scale (AOS), the Revised Foot Function Index (FFI-R), and the Short-Form 36 (SF-36) outcomes questionnaires were administered at most recent followup. Postoperative imaging was reviewed for evidence of healing. Eight patients with a mean age of 47.5 (range, 18 to 68) years were included in this study. The mean followup time was 61 (range, 32 to 72) months. Two patients underwent concomitant talonavicular arthrodesis. Two patients underwent additional procedures to address continued nonunion of the navicular. Neither patient elected to complete the outcomes questionnaires. The mean postoperative FFI score was 35.2 (range, 16.6 to 59). SF-36 subscales were as follows: bodily pain, 53; general health, 55; mental health, 75; physical function, 56; role emotional, 61; role physical, 37.5; social function, 71; and vitality, 56. The mean postoperative AOS pain score was 27.9 (range, 0 to 46.2) and the average disability score was 31.4 (range, 0 to 78.2). Postoperative imaging revealed consolidation and full healing in six of eight patients. Vascularized pedicle bone grafting is a treatment option for patients with chronic nonunion or osteonecrosis of the navicular. Additionally, it may serve as an adjunct procedure to provide increased vascularity to talonavicular arthrodesis in cases of navicular osteonecrosis and talonavicular arthritis.

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

    African Journals Online (AJOL)

    Orthopedic surgeons in developed countries have the option of choosing vascularized bone transfers, bone transport, allogenic bone grafts, bone graft substitutes ... tissue envelope assessment, neurological examination, and debridement under general anesthesia with fracture stabilization with external fixators or casts.

  3. 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.

  4. Effect of fish oil supplementation on graft patency and cardiovascular events among patients with new synthetic arteriovenous hemodialysis grafts: a randomized controlled trial.

    Science.gov (United States)

    Lok, Charmaine E; Moist, Louise; Hemmelgarn, Brenda R; Tonelli, Marcello; Vazquez, Miguel A; Dorval, Marc; Oliver, Matthew; Donnelly, Sandra; Allon, Michael; Stanley, Kenneth

    2012-05-02

    Synthetic arteriovenous grafts, an important option for hemodialysis vascular access, are prone to recurrent stenosis and thrombosis. Supplementation with fish oils has theoretical appeal for preventing these outcomes. To determine the effect of fish oil on synthetic hemodialysis graft patency and cardiovascular events. The Fish Oil Inhibition of Stenosis in Hemodialysis Grafts (FISH) study, a randomized, double-blind, controlled clinical trial conducted at 15 North American dialysis centers from November 2003 through December 2010 and enrolling 201 adults with stage 5 chronic kidney disease (50% women, 63% white, 53% with diabetes), with follow-up for 12 months after graft creation. Participants were randomly allocated to receive fish oil capsules (four 1-g capsules/d) or matching placebo on day 7 after graft creation. Proportion of participants experiencing graft thrombosis or radiological or surgical intervention during 12 months' follow-up. The risk of the primary outcome did not differ between fish oil and placebo recipients (48/99 [48%] vs 60/97 [62%], respectively; relative risk, 0.78 [95% CI, 0.60 to 1.03; P = .06]). However, the rate of graft failure was lower in the fish oil group (3.43 vs 5.95 per 1000 access-days; incidence rate ratio [IRR], 0.58 [95% CI, 0.44 to 0.75; P oil group, there were half as many thromboses (1.71 vs 3.41 per 1000 access-days; IRR, 0.50 [95% CI, 0.35 to 0.72; P oil ingestion did not decrease the proportion of grafts with loss of native patency within 12 months. Although fish oil improved some relevant secondary outcomes such as graft patency, rates of thrombosis, and interventions, other potential benefits on cardiovascular events require confirmation in future studies. isrctn.org Identifier: ISRCTN15838383.

  5. Angiogenic potential of human macrophages on electrospun bioresorbable vascular grafts

    Energy Technology Data Exchange (ETDEWEB)

    Garg, K; Sell, S A; Madurantakam, P; Bowlin, G L, E-mail: glbowlin@vcu.ed [Virginia Commonwealth University, Richmond, VA 23284 (United States)

    2009-06-15

    The aim of this study was to investigate macrophage interactions with electrospun scaffolds and quantify the expression of key angiogenic growth factors in vitro. This study will further help in evaluating the potential of these electrospun constructs as vascular grafts for tissue repair and regeneration in situ. Human peripheral blood macrophages were seeded in serum free media on electrospun (10 mm) discs of polydioxanone (PDO), elastin and PDO:elastin blends (50:50, 70:30 and 90:10). The growth factor secretion was analyzed by ELISA. Macrophages produced high levels of vascular endothelial growth factor and acidic fibroblast growth factor. Transforming growth factor beta-1 (TGF-beta1) secretion was relatively low and there was negligible production of basic fibroblast growth factor. Therefore, it can be anticipated that these scaffolds will support tissue regeneration and angiogenesis. (communication)

  6. Development of biomimetic thermoplastic polyurethane/fibroin small-diameter vascular grafts via a novel electrospinning approach.

    Science.gov (United States)

    Yu, Emily; Mi, Hao-Yang; Zhang, Jue; Thomson, James A; Turng, Lih-Sheng

    2018-04-01

    A new electrospinning approach for fabricating vascular grafts with a layered, circumferentially aligned, and micro-wavy fibrous structure similar to natural elastic tissues has been developed. The customized electrospinning collector was able to generate wavy fibers using the dynamic "jump rope" collecting process, which also solved the sample removal problem for mandrel-type collectors. In this study, natural silk fibroin and synthetic thermoplastic polyurethane (TPU) were combined at different weight ratios to produce hybrid small-diameter vascular grafts. The purpose of combining these two materials was to leverage the bioactivity and tunable mechanical properties of these natural and synthetic materials. Results showed that the electrospun fiber morphology was highly influenced by the material compositions and solvents employed. All of the TPU/fibroin hybrid grafts had mechanical properties comparable to natural blood vessels. The circumferentially aligned and wavy biomimetic configuration provided the grafts with a sufficient toe region and the capacity for long-term usage under repeated dilatation and contraction. Cell culture tests with human endothelial cells (EC) also revealed high cell viability and good biocompatibility for these grafts. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 985-996, 2018. © 2017 Wiley Periodicals, Inc.

  7. Biological and physical properties of autogenous vascularized fibular grafts in dogs

    International Nuclear Information System (INIS)

    Goldberg, V.M.; Stevenson, S.; Shaffer, J.W.; Davy, D.; Klein, L.; Zika, J.; Field, G.

    1990-01-01

    The biological and biomechanical properties of normal fibulae, fibulae that had had a sham operation, and both vascularized and non-vascularized autogenous grafts were studied in dogs at three months after the operation. The study was designed to quantify and correlate changes in these properties in orthotopic, stably fixed, weight-bearing grafts and to provide a baseline for additional studies of allografts. The grafts were eight centimeters long and internally fixed. The mechanical properties of the grafts were studied by torsional testing. Metabolic turnover of the grafts was evaluated by preoperative labeling of the dogs with 3H-tetracycline for resorption of bone mineral and with 3H-proline for turnover of collagen. Cortical bone area and porosity were measured. Postoperative formation of bone was evaluated by sequential labeling with fluorochrome. The vascularized grafts resembled the fibulae that had had a sham operation and those that had not had an operation with regard to the total number of osteons and the remodeling process, as measured both morphometrically and metabolically. The vascularized grafts were stronger and stiffer than the non-vascularized grafts and were not different from the bones that had had a sham operation. In contrast, the non-vascularized grafts were smaller, weaker, less stiff, and more porotic, had fewer osteons, and demonstrated increased turnover and resorption compared with the vascularized grafts, the bones that had had a sham operation, and the bones that had not been operated on

  8. Mechanical Property Characterization of Electrospun Recombinant Human Tropoelastin for Vascular Graft Biomaterials

    OpenAIRE

    McKenna, Kathryn A.; Hinds, Monica T.; Sarao, Rebecca C.; Wu, Ping-Cheng; Maslen, Cheryl L.; Glanville, Robert W.; Babcock, Darcie; Gregory, Kenton W.

    2011-01-01

    The development of vascular grafts has focused on finding a biomaterial that is non-thrombogenic, minimizes intimal hyperplasia, matches the mechanical properties of native vessels and allows for regeneration of arterial tissue. In this study, the structural and mechanical properties and the vascular cell compatibility of electrospun recombinant human tropoelastin (rTE) were evaluated as a potential vascular graft support matrix. Disuccinimidyl suberate (DSS) was used to cross-link electrospu...

  9. 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.

  10. Modular Small Diameter Vascular Grafts with Bioactive Functionalities

    Science.gov (United States)

    Neufurth, Meik; Wang, Xiaohong; Tolba, Emad; Dorweiler, Bernhard; Schröder, Heinz C.; Link, Thorben; Diehl-Seifert, Bärbel; Müller, Werner E. G.

    2015-01-01

    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 Ca2+ through formation of Ca2+ bridges between the polyanions, alginate, N,O-CMC, and polyP (alginate-Ca2+-N,O-CMC-polyP). The bTEBV are formed by pressing the hydrogel through an extruder into a hardening solution, containing Ca2+. 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-Ca2+-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 degradable

  11. Evaluation of graft patency by intravenous digital subtraction angiography after vascular reconstruction

    International Nuclear Information System (INIS)

    Kuribayashi, Sachio; Ootaki, Makoto; Watabe, Tsuneya; Matsuyama, Seiya

    1985-01-01

    Intravenous digital subtraction angiography (IVDSA) was employed to evaluate graft patency after reconstructive vascular surgery in 45 cases with various vascular diseases. IVDSA offered equally valuable information about the patency of the graft, compared with conventional arteriography. In the peripheral vascular disease, IVDSA readily demonstrated patency or occlusion of the graft, even in the complex one, and the result of evaluation by IVDSA correlated well with that inferred by postoperative change in ankle pressure index measured by Doppler ultrasound technique. In the aortic disease, IVDSA was effective to rule out stenosis or leakage at the anastomotic site of the graft, and was also useful in the detection of the patency of the reconstructed inferior mesenteric artery after surgery for abdominal aortic aneurysm. The procedure in IVDSA is simple and safe, and it can be performed on an outpatient basis. IVDSA is a reliable and valuable approach in the evaluation of the graft patency after reconstructive vascular surgery. (author)

  12. 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.

  13. 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.

  14. Vacuum-assisted closure therapy for vascular graft infection (Szilagyi grade III) in the groin-a 10-year multi-center experience.

    Science.gov (United States)

    Verma, Himanshu; Ktenidis, Kiriakos; George, Robbie K; Tripathi, Ramesh

    2015-06-01

    complications during VAC therapy were wound fluid retention in 2 cases and an increased need for analgesics in 12 cases (16·66%). Negative pressure wound therapy (NPWT) has been reported to be useful in the treatment of severe wound infections. Even in the presence of synthetic vascular graft material, NPWT can greatly simplify challenging wound-healing problems leading to wound dehiscence and its sequelae. Our long-term experience demonstrates the safety and effectiveness of VAC therapy in the management of deep graft infections. © 2013 The Authors. International Wound Journal © 2013 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

  15. Free vascularized fibula grafts for salvage of failed oncologic long bone reconstruction and pathologic fractures.

    Science.gov (United States)

    Friedrich, Jeffrey B; Moran, Stephen L; Bishop, Allen T; Shin, Alexander Y

    2009-01-01

    Vascularized bone grafts, particularly the free fibula transfer, have incited revolutionary changes in the field of skeletal reconstruction. In no place has this been more evident than in oncologic reconstruction. The free vascularized fibula graft has been used to good effect for primary long-bone reconstruction, long-bone allograft complication salvage, and pathologic fracture salvage of the long bones. Although many of these procedures often entail significant complications, limb salvage has been made possible in a majority of patients using transfers of free vascularized fibula grafts. The purpose of this review is to critically evaluate the technique of onlay free vascularized fibula grafts for salvage of allograft complications and pathologic fractures of the long bones. This will be accomplished by reviewing the problem of allograft complications and pathologic fractures, the current treatment modalities available, the outcomes of these treatments, and future directions of treatment for this particular problem.

  16. BIOMECHANICAL REMODELING OF BIODEGRADABLE SMALL-DIAMETER VASCULAR GRAFTS IN SITU

    Directory of Open Access Journals (Sweden)

    T. V. Glushkova

    2016-01-01

    Full Text Available Aim: to evaluate the biomechanical remodeling of polymer grafts modified with vascular endothelial growth factor (VEGF after implantation into rat abdominal aorta.Materials and methods. Vascular grafts of2 mmdiameter were fabricated by electrospinning from polycaprolactone (PCL and a mixture of poly (3-hydroxybutyrate-co-3-hydroxyvalerate and PCL. The grafts were modified with VEGF by biphasic electrospinning. Morphology of the grafts was assessed by scanning electron microscopy. Physico-mechanical properties of PCL and PHBV/PCL grafts were estimated using uniaxial tensile test and physiological circulating system equipped with state-of-theart ultrasound vascular wall tracking system. Physico-mechanical testing of PCL/VEGF and PHBV/PCL/VEGF was performed before and after implantation into rat abdominal aorta for 6 months. The modeling of coronary artery bypass grafting (CABG was performed by finite element analysis for modified grafts.Results. Durability of PCL and PHBV/PCL grafts did not differ from that of human internal mammary artery; however, elasticity and stiffness of these grafts were higher compared to internal mammary artery. Viscoelastic properties of the grafts were comparable to those of native blood vessels. Modification of the grafts with VEGF reduced material stiffness. Six months postimplantation, PCL/VEGF and PHBV/PCL/VEGF were integrated with aortic tissue that induced changes in the physico-mechanical properties of the grafts similar to the native vessel. Biomechanical modeling confirmed the functioning of modified grafts in bypass position for CABG.Conclusion. PCL/VEGF and PHBV/PCL/VEGF grafts have satisfactory physico-mechanical properties and can be potentially used in the reconstruction of blood vessels. 

  17. Comprehensive mechanical characterization of PLA fabric combined with PCL to form a composite structure vascular graft.

    Science.gov (United States)

    Li, Chaojing; Wang, Fujun; Douglas, Graeham; Zhang, Ze; Guidoin, Robert; Wang, Lu

    2017-05-01

    Vascular grafts made by tissue engineering processes are prone to buckling and twisting, which can impede blood flow and lead to collapse of the vessel. These vascular conduits may suffer not only from insufficient tensile strength, but also from vulnerabilities related to compression, torsion, and pulsatile pressurization. Aiming to develop a tissue engineering-inspired blood conduit, composite vascular graft (cVG) prototypes were created by combining a flexible polylactic acid (PLA) knitted fabric with a soft polycaprolactone (PCL) matrix. The graft is to be populated in-situ with cellular migration and proliferation into the device. Comprehensive characterizations probed the relationship between structure and mechanical properties of the different cVG prototypes. The composite grafts exhibited major improvements in mechanical characteristics compared to single-material devices, with particular improvement in compression and torsional resistance. A commercial expanded polytetrafluoroethylene (ePTFE) vascular graft was used as a control against the proposed composite vascular grafts. CVG devices showed high tensile strength, high bursting strength, and improved suture retention. Compression, elastic recovery, and compliance were similar to those for the ePTFE graft. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. 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 ...

  19. Vascularized pedicle jejunal graft for closure of large duodenal defect in a dog.

    Science.gov (United States)

    Massie, Anna; McFadden, Michael

    2016-11-01

    A Labrador retriever dog was presented for intestinal obstruction resulting in devitalization of portions of the duodenum. A severe perforation, accounting for 70% duodenal circumference, was present at the level of the duodenal papilla. A vascularized jejunal graft was used to close the perforation, representing novel utilization of this grafting technique.

  20. 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.

  1. Non-vascularized iliac bone grafting for scaphoid nonunion with avascular necrosis.

    Science.gov (United States)

    Kim, Jihyeung; Park, Jin Woo; Chung, Jeehyeok; Jeong Bae, Kee; Gong, Hyun Sik; Baek, Goo Hyun

    2018-01-01

    We present the surgical outcomes of non-vascularized bone grafting taken from the iliac crest in 24 patients with scaphoid nonunion and avascular necrosis. The Fisk-Fernandez technique was used in 11 patients, and cancellous bone grafting was used in 13 patients. Bony union was achieved in 22 of the 24 patients. Non-vascularized iliac bone grafting can be used for the surgical management of scaphoid nonunion with avascular necrosis. Although revascularization of the proximal fragment after surgery was not evaluated, bony union was confirmed in nearly all patients. IV.

  2. The in vivo blood compatibility of bio-inspired small diameter vascular graft: effect of submicron longitudinally aligned topography

    Science.gov (United States)

    2013-01-01

    Background Cardiovascular disease is the leading cause of deaths worldwide and the arterial reconstructive surgery remains the treatment of choice. Although large diameter vascular grafts have been widely used in clinical practices, there is an urgent need to develop a small diameter vascular graft with enhanced blood compatibility. Herein, we fabricated a small diameter vascular graft with submicron longitudinally aligned topography, which mimicked the tunica intima of the native arterial vessels and were tested in Sprague–Dawley (SD) rats. Methods Vascular grafts with aligned and smooth topography were prepared by electrospinning and were connected to the abdominal aorta of the SD rats to evaluate their blood compatibility. Graft patency and platelet adhesion were evaluated by color Doppler ultrasound and immunofluorescence respectively. Results We observed a significant higher patency rate (p = 0.021) and less thrombus formation in vascular graft with aligned topography than vascular graft with smooth topography. However, no significant difference between the adhesion rates on both vascular grafts (smooth/aligned: 0.35‰/0.12‰, p > 0.05) was observed. Moreover, both vascular grafts had few adherent activated platelets on the luminal surface. Conclusion Bionic vascular graft showed enhanced blood compatibility due to the effect of surface topography. Therefore, it has considerable potential for using in clinical application. PMID:24083888

  3. Submillimeter Diameter Poly(Vinyl Alcohol) Vascular Graft Patency in Rabbit Model

    Science.gov (United States)

    Cutiongco, Marie F. A.; Kukumberg, Marek; Peneyra, Jonnathan L.; Yeo, Matthew S.; Yao, Jia Y.; Rufaihah, Abdul Jalil; Le Visage, Catherine; Ho, Jackie Pei; Yim, Evelyn K. F.

    2016-01-01

    Microvascular surgery is becoming a prevalent surgical practice. Replantation, hand reconstruction, orthopedic, and free tissue transfer procedures all rely on microvascular surgery for the repair of venous and arterial defects at the millimeter and submillimeter levels. Often, a vascular graft is required for the procedure as a means to bridge the gap between native arteries. While autologous vessels are desired for their bioactivity and non-thrombogenicity, the tedious harvest process, lack of availability, and caliber or mechanical mismatch contribute to graft failure. Thus, there is a need for an off-the-shelf artificial vascular graft that has low thrombogenic properties and mechanical properties matching those of submillimeter vessels. Poly(vinyl alcohol) hydrogel (PVA) has excellent prospects as a vascular graft due to its bioinertness, low thrombogenicity, high water content, and tunable mechanical properties. Here, we fabricated PVA grafts with submillimeter diameter and mechanical properties that closely approximated those of the rabbit femoral artery. In vitro platelet adhesion and microparticle release assay verified the low thrombogenicity of PVA. A stringent proof-of-concept in vivo test was performed by implanting PVA grafts in rabbit femoral artery with multilevel arterial occlusion. Laser Doppler measurements indicated the improved perfusion of the distal limb after implantation with PVA grafts. Moreover, ultrasound Doppler and angiography verified that the submillimeter diameter PVA vascular grafts remained patent for 2 weeks without the aid of anticoagulant or antithrombotics. Endothelial cells were observed in the luminal surface of one patent PVA graft. The advantageous non-thrombogenic and tunable mechanical properties of PVA that are retained even in the submillimeter diameter dimensions support the application of this biomaterial for vascular replacement in microvascular surgery. PMID:27376059

  4. 111 In-labeled leukocytes in the detection of prosthetic vascular graft infections

    International Nuclear Information System (INIS)

    Williamson, M.R.; Boyd, C.M.; Read, R.C.; Thompson, B.W.; Barnes, R.W.; Shah, H.R.; Balachandran, S.; Ferris, E.J.

    1986-01-01

    Making a clinical diagnosis of infection in prosthetic vascular grafts is difficult but when undiagnosed, this condition has a high mortality rate. Using Indium-111-labeled white-blood cells, 30 scans were performed in 21 patients suspected of having a prosthetic graft infection. The diagnosis of infected graft was confirmed by surgery in all cases, and lack of infection was established by resolution of symptoms with conservative therapy. Twenty-four hour scans of autologous Indium-111 leukocytes were obtained, and correlative CT studies were done in 11 cases. There were 13 infected grafts at surgery (purulent material present), and scans were positive in all (100% sensitivity); of 17 scans, there were 15 true negatives and two false positives (88% specificity). Using the criteria of gas or fluid around the graft, the sensitivity of CT was only 37% in a small subset of these patients. One-half of the cases in which infection was suspected clinically had no infection and had negative scans. Various types of grafts and graft materials were used, and there was no correlation with presence or absence of infection on the basis of the type of graft. Extragraft infection sites were found in five patients. In conclusion, use of Indium-111 leukocytes has been found to be an accurate and valuable diagnostic method for evaluation of suspected prosthetic vascular graft infection, and to have higher diagnostic accuracy than CT

  5. Vascularized fibular graft combined with vacuum assisted closure in ...

    African Journals Online (AJOL)

    The flowthrough fibular graft combined with Vacuum Assisted Closure (VAC) controlled the infection, shortened the course of treatment, and effectively restored limb function when applied to the treatment of tibial defects. Keywords: Tibial defect, Flow-through fibular graft, Vacuum Assisted Closure, Chronic Osteomyelitis ...

  6. The vascular pattern and viability of microvascularized rib grafts based on periosteal circulation--an experimental study

    International Nuclear Information System (INIS)

    Papanastasiou, V.W.; Lalonde, D.H.; Williams, H.B.

    1984-01-01

    Previous reports have stressed the importance of the nutrient blood supply in rib grafts transferred by microvascular anastomoses. In the present experimental study, we have demonstrated that a rib graft transferred by microvascular anastomoses based on periosteal vessels can survive; vascular clearing studies demonstrated that the vascularity of these grafts extends not only into the cortex but the medulla as well. The relative facility of harvesting these grafts (compared with those based on nutrient vessels) should make them the favored choice. Technetium bone scintigraphy proved accurate in the assessment of both vascular pattern and microanastomotic patency. Tetracycline labeling did not correlate well with the patency of a rib graft's pedicle blood supply

  7. MR imaging of avascular scaphoid nonunion before and after vascularized bone grafting

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Suzanne E.; Tschering-Vogel, Dechen; Martin, Matthias [University Hospital of Bern, Inselspital, Department of Radiology, Bern (Switzerland); Steinbach, Lynne S. [University of California San Francisco, Department of Radiology, San Francisco, California (United States); Nagy, Ladislav [University Hospital of Bern, Inselspital, Department of Orthopedic Surgery, Bern (Switzerland)

    2005-06-01

    To investigate the magnetic resonance (MR) imaging appearances of chronic nonunion of the scaphoid with proximal pole avascular necrosis before and after insertion of a vascularized bone graft, using computed tomography (CT) as the imaging gold standard. A retrospective study was performed involving MR imaging (n=26), CT scans (n=37) and radiographs (n=52) of 13 men (mean age 29 years, age range 20-38 years) with avascular scaphoid nonunion. Avascular necrosis of the scaphoid proximal pole was confirmed intraoperatively (n=13). MR images were acquired preoperatively and following placement of a vascularized bone graft. Scaphoid MR signal characteristics were assessed for evidence of vascular bone graft incorporation and revascularization of the bone marrow of the proximal pole of the scaphoid and compared with the gold standard of CT. Surgical and clinical notes were reviewed with a minimum 3 year imaging and clinical follow-up in all patients. Graft incorporation with revascularization of the proximal pole of the scaphoid was documented in 9 patients (69%). Graft failure with persistent pseudoarthrosis and avascular necrosis of the scaphoid was seen in 4 patients (31%). MR imaging is useful to determine whether vascularized bone graft incorporation and revascularization of the proximal pole of the scaphoid has occurred in the setting of avascular scaphoid nonunion. (orig.)

  8. MR imaging of avascular scaphoid nonunion before and after vascularized bone grafting

    International Nuclear Information System (INIS)

    Anderson, Suzanne E.; Tschering-Vogel, Dechen; Martin, Matthias; Steinbach, Lynne S.; Nagy, Ladislav

    2005-01-01

    To investigate the magnetic resonance (MR) imaging appearances of chronic nonunion of the scaphoid with proximal pole avascular necrosis before and after insertion of a vascularized bone graft, using computed tomography (CT) as the imaging gold standard. A retrospective study was performed involving MR imaging (n=26), CT scans (n=37) and radiographs (n=52) of 13 men (mean age 29 years, age range 20-38 years) with avascular scaphoid nonunion. Avascular necrosis of the scaphoid proximal pole was confirmed intraoperatively (n=13). MR images were acquired preoperatively and following placement of a vascularized bone graft. Scaphoid MR signal characteristics were assessed for evidence of vascular bone graft incorporation and revascularization of the bone marrow of the proximal pole of the scaphoid and compared with the gold standard of CT. Surgical and clinical notes were reviewed with a minimum 3 year imaging and clinical follow-up in all patients. Graft incorporation with revascularization of the proximal pole of the scaphoid was documented in 9 patients (69%). Graft failure with persistent pseudoarthrosis and avascular necrosis of the scaphoid was seen in 4 patients (31%). MR imaging is useful to determine whether vascularized bone graft incorporation and revascularization of the proximal pole of the scaphoid has occurred in the setting of avascular scaphoid nonunion. (orig.)

  9. A new method of prefabricated vascularized allogenic bone grafts for maxillo-mandibular reconstruction

    International Nuclear Information System (INIS)

    Pill-Hoon Choung

    1999-01-01

    Although there are various applications of allogenic bone grafts, a new technique of prevascularized lyophilized allogenic bone grafting for maxillo-mandibular reconstruction will be presented. Allogenic bone has been made by author's protocol for jaw defects as a powder, chip or block bone type. The author used lyophilized allogenic bone grafts for discontinuity defects as a block bone. In those cases, neovascularization and resorption of the allogenic bone were important factors for success of grafting. To overcome the problems, the author designed the technique of prefabricated vascularization of allogenic bone, which was lyophilized cranium, with an application of bovine BMP or not. Lyophilized cranial bone was designed for the defects and was put into the scalp. After confirming a hot spot via scintigram several months later, vascularized allogenic bone was harvested pedicled on the parietotemporal fascia based on the superficial temporal artery and vein. Vascularized allogenic cranial bone was rotated into the defect and fixed rigidly. Postoperatively, there was no severe resorption and functional disturbance of the mandible. In this technique, BMP seems to be an important role to help osteogenesis and neovascularization. Eight patients underwent prefabricated vascularization of allogenic bone grafts. Among them, four cases of reconstruction in mandibular discontinuity defects and one case of reconstruction in maxillectomy defect underwent this method, which will be presented with good results. This method may be an alternative technique of microvascular free bone graft

  10. Stenting and overdilating small Gore-Tex vascular grafts in complex congenital heart disease.

    Science.gov (United States)

    Penford, Gemma; Quandt, Daniel; Mehta, Chetan; Bhole, Vinay; Dhillon, Rami; Seale, Anna; Stumper, Oliver

    2018-01-01

    Gore-Tex ® grafts are integral in the management of congenital heart disease. Issues of graft stenosis or somatic outgrowth may precipitate high-risk early surgery, and catheter intervention is a relatively under-reported management option. To assess efficacy, safety, and outcomes of stenting and overdilating small Gore-Tex ® vascular grafts with the aim of optimizing surgical timing. Retrospective analysis of single-center, 13-year experience of 93 graft stenting interventions or reintervention in 80 patients, with the aim of relieving stenosis ± overdilation, to depose surgical graft revision or optimize surgical timing and candidacy. Median preintervention graft diameter was 52% (IQR 43-63) of nominal size, postintervention this increased to median 102% (IQR 96-120) [P Gore-Tex ® vascular grafts can be stented effectively and expanded beyond nominal diameters by around +26%. This improves oxygen saturations, providing excellent palliation and optimized surgical timing. Adverse events are most frequent in precavopulmonary shunt patients. Gore-Tex ® grafts are widely used in the palliation of cyanotic congenital heart disease. Grafts may become stenosed and do not allow for somatic growth. Over a 13 year period, graft stenting was performed in 80 patients (93 technically successful interventions, 4 unsuccessful.) Median internal lumen change was +50% (of nominal graft size), mean oxygen saturation change +13%. Over-dilation was performed in more than half of the cohort, with a median gain of +26% on nominal graft size. In precavopulmonary shunt patients, there was a moderate incidence of serious complications. Clinically useful deferral of surgery was achieved for the majority. © 2018 Wiley Periodicals, Inc.

  11. Adhesion, Growth, and Maturation of Vascular Smooth Muscle Cells on Low-Density Polyethylene Grafted with Bioactive Substances

    Directory of Open Access Journals (Sweden)

    Martin Parizek

    2013-01-01

    Full Text Available The attractiveness of synthetic polymers for cell colonization can be affected by physical, chemical, and biological modification of the polymer surface. In this study, low-density polyethylene (LDPE was treated by an Ar+ plasma discharge and then grafted with biologically active substances, namely, glycine (Gly, polyethylene glycol (PEG, bovine serum albumin (BSA, colloidal carbon particles (C, or BSA+C. All modifications increased the oxygen content, the wettability, and the surface free energy of the materials compared to the pristine LDPE, but these changes were most pronounced in LDPE with Gly or PEG, where all the three values were higher than in the only plasma-treated samples. When seeded with vascular smooth muscle cells (VSMCs, the Gly- or PEG-grafted samples increased mainly the spreading and concentration of focal adhesion proteins talin and vinculin in these cells. LDPE grafted with BSA or BSA+C showed a similar oxygen content and similar wettability, as the samples only treated with plasma, but the nano- and submicron-scale irregularities on their surface were more pronounced and of a different shape. These samples promoted predominantly the growth, the formation of a confluent layer, and phenotypic maturation of VSMC, demonstrated by higher concentrations of contractile proteins alpha-actin and SM1 and SM2 myosins. Thus, the behavior of VSMC on LDPE can be regulated by the type of bioactive substances that are grafted.

  12. Osteonecrosis of femoral head: Treatment by core decompression and vascular pedicle grafting

    Directory of Open Access Journals (Sweden)

    Babhulkar Sudhir

    2009-01-01

    Full Text Available Background: Femoral head-preserving core decompression and bone grafting have shown excellent result in preventing collapse. The use of vascularized grafts have shown better clinical results. The vascular pedicle bone graft is an easy to perform operation and does not require special equipment. We analyzed and report a series of patients of osteonecrosis of femoral head treated by core decompression and vascular pedicle grafting of part of iliac crest based on deep circumflex iliac vessels. Materials and Methods: The article comprises of the retrospective study of 31 patients of osteonecrosis of femoral head in stage II and III treated with core decompression and vascular pedicle grafting by using part of iliac crest with deep circumflex iliac vessels from January 1990 to December 2005. The young patients with a mean age 32 years (18-52 years with a minimum follow-up of five years were included for analysis. Sixteen patients had osteonecrosis following alcohol abuse, 12 patients following corticosteroid consumption, 3 patients had idiopathic osteonecrosis. Nine patients were stage IIB, and 22 patients were stage IIIC according to ARCO′s system. The core decompression and vascular pedicle grafting was performed by anterior approach by using part of iliac crest with deep circumflex iliac vessels. Results: Digital subtraction arteriography performed in 9 patients at the end of 12 weeks showed the patency of deep circumflex artery in all cases, and bone scan performed in 6 other patients showed high uptake in the grafted area of the femoral head proving the efficacy of the operative procedure. Out of 31 patients, only one patient progressed to collapse and total joint replacement was advised. At the final follow up period of 5-8 years, Harris Hip Score improved mean ± SD of 28.2 ± 6.4 ( p < 0.05. Forty-eight percent of patients had an improvement in Harris Hip Score of more that 28 points. Conclusion: The core decompression and vascular pedicle

  13. Susceptibility of ePTFE vascular grafts and bioengineered human acellular vessels to infection.

    Science.gov (United States)

    Kirkton, Robert D; Prichard, Heather L; Santiago-Maysonet, Maribel; Niklason, Laura E; Lawson, Jeffrey H; Dahl, Shannon L M

    2018-01-01

    Synthetic expanded polytetrafluorethylene (ePTFE) grafts are routinely used for vascular repair and reconstruction but prone to sustained bacterial infections. Investigational bioengineered human acellular vessels (HAVs) have shown clinical success and may confer lower susceptibility to infection. Here we directly compared the susceptibility of ePTFE grafts and HAV to bacterial contamination in a preclinical model of infection. Sections (1 cm 2 ) of ePTFE (n = 42) or HAV (n = 42) were inserted within bilateral subcutaneous pockets on the dorsum of rats and inoculated with Staphylococcus aureus (10 7  CFU/0.25 mL) or Escherichia coli (10 8  CFU/0.25 mL) before wound closure. Two weeks later, the implant sites were scored for abscess formation and explanted materials were halved for quantification of microbial recovery and histological analyses. The ePTFE implants had significantly higher abscess formation scores for both S. aureus and E. coli inoculations compared to that of HAV. In addition, significantly more bacteria were recovered from explanted ePTFE compared to HAV. Gram staining of explanted tissue sections revealed interstitial bacterial contamination within ePTFE, whereas no bacteria were identified in HAV tissue sections. Numerous CD45 + leukocytes, predominantly neutrophils, were found surrounding the ePTFE implants but minimal intact neutrophils were observed within the ePTFE matrix. The host cells surrounding and infiltrating the HAV explants were primarily nonleukocytes (CD45 - ). In an established animal model of infection, HAV was significantly less susceptible to bacterial colonization and abscess formation than ePTFE. The preclinical findings presented in this manuscript, combined with previously published clinical observations, suggest that bioengineered HAV may exhibit low rates of infection. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  14. Preliminary in Vivo Evaluation of a Hybrid Armored Vascular Graft Combining Electrospinning and Additive Manufacturing Techniques

    Directory of Open Access Journals (Sweden)

    Cristiano Spadaccio

    2016-01-01

    Full Text Available In this study, we tested in vivo effectiveness of a previously developed poly-L-lactide/poly-8-caprolactone armored vascular graft releasing heparin. This bioprosthesis was designed in order to overcome the main drawbacks of tissue-engineered vascular grafts, mainly concerning poor mechanical properties, thrombogenicity, and endothelialization. The bioprosthesis was successfully implanted in an aortic vascular reconstruction model in rabbits. All grafts implanted were patent at four weeks postoperatively and have been adequately populated by endogenous cells without signs of thrombosis or structural failure and with no need of antiplatelet therapy. The results of this preliminary study might warrant for further larger controlled in vivo studies to further confirm these findings.

  15. Vascular Endothelial Growth Factor Improves Physico-Mechanical Properties and Enhances Endothelialization of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/Poly(ε-caprolactone) Small-Diameter Vascular Grafts In vivo.

    Science.gov (United States)

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

    2016-01-01

    The combination of a natural polymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and a synthetic hydrophobic polymer poly(ε-caprolactone) (PCL) is promising for the preparation of biodegradable and biocompatible small-diameter vascular grafts for bypass surgery. However, physico-mechanical properties and endothelialization rate of PHBV/PCL grafts are poor. We suggested that incorporation of vascular endothelial growth factor (VEGF) into PHBV/PCL grafts may improve their physico-mechanical properties and enhance endothelialization. Here we compared morphology, physico-mechanical properties, and in vivo performance of electrospun small-diameter vascular grafts prepared from PHBV/PCL with and without VEGF. Structure of the graft surface and physico-mechanical properties were examined by scanning electron microscopy and universal testing machine, respectively. Grafts were implanted into rat abdominal aorta for 1, 3, and 6 months with the further histological, immunohistochemical, and immunofluorescence examination. PHBV/PCL grafts with and without VEGF were highly porous and consisted mostly of nanoscale and microscale fibers, respectively. Mean pore diameter and mean pore area were significantly lower in PHBV/PCL/VEGF compared to PHBV/PCL grafts (1.47 μm and 10.05 μm(2); 2.63 μm and 47.13 μm(2), respectively). Durability, elasticity, and stiffness of PHBV/PCL grafts with VEGF were more similar to internal mammary artery compared to those without, particularly 6 months postimplantation. Both qualitative examination and quantitative image analysis showed that three-fourths of PHBV/PCL grafts with VEGF were patent and had many CD31-, CD34-, and vWF-positive cells at their inner surface. However, all PHBV/PCL grafts without VEGF were occluded and had no or a few CD31-positive cells at the inner surface. Therefore, VEGF enhanced endothelialization and improved graft patency at all the time points in a rat abdominal aorta replacement model. In conclusion, PHBV

  16. SANS and SAXS Study of Block and Graft Copolymers Containing Natural and Synthetic Rubbers

    Science.gov (United States)

    Hasegawa, H.

    2008-03-01

    Small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS) are excellent techniques to study nano-scale concentration fluctuations in the two-component polymer systems such as block and graft copolymers and polymer blends. The miscibility, phase transitions, microphase-separated structures and interface thicknesses were investigated by SANS and SAXS for the block and graft copolymers, which at least contain natural or synthetic rubber as one component.

  17. Outcomes after heparin-induced thrombocytopenia in patients with Propaten vascular grafts.

    Science.gov (United States)

    Kasirajan, Karthikeshwar

    2012-08-01

    Heparin-induced thrombocytopenia (HIT) can result in a life- or limb-threatening condition that can be reversed with early detection and prompt discontinuation of systemic heparin. The advent of heparin-bonded grafts may introduce a new level of complexity in some patients with a suspected diagnosis of HIT. This review evaluates the outcomes of patients who received the Gore Propaten vascular graft with a subsequent suspicion of HIT. This is a retrospective analysis of cases with suspected type II HIT after implant of the Propaten vascular graft that were reported to W.L. Gore & Associates. Data reviewed included clinical studies, including physician-sponsored studies, both inside and outside the United States; published literature; and Gore's product surveillance records. Overall, as of June 2011, there have been 27 cases (27 patients and 30 vascular grafts) of suspected HIT after graft implant. Of these 27 patients, 18 were tested for HIT antibodies (enzyme-linked immunosorbent assay, heparin-induced platelet activation test, serotonin release assay, drug-induced platelet activation test, platelet aggregation test, an HIT panel, or an unknown HIT test), with a positive test result in 17 of the 18 cases. In 5 of the 18 cases, patients were tested with two distinct HIT assays, resulting in one positive and one negative test. Among patients with available data, the mean preoperative heparin dose was 4850 ± 1634 U, and four patients had a postoperative heparin drip. The mean preoperative platelet count was 227,000 ± 71,616. Mean platelet count at time of diagnosis of HIT was 53,429 ± 36,832. For the majority of those patients known to have had heparin discontinued once HIT was suspected, Argatroban was the anticoagulant of choice. Sixteen patients had grafts that remained implanted and in circulation, eight patients had grafts that were explanted, two patients had grafts that were ligated in situ, and the outcome was unknown for one patient. Among the 16 patients

  18. Laccase-Mediated Grafting on Biopolymers and Synthetic Polymers

    NARCIS (Netherlands)

    Slagman, Sjoerd; Zuilhof, Han; Franssen, Maurice C.R.

    2018-01-01

    Laccase-mediated grafting on lignocelluloses has gained considerable attention as an environmentally benign method to covalently modify wood, paper and cork. In recent decades this technique has also been employed to modify fibres with a polysaccharide backbone, such as cellulose or chitosan, to

  19. Convenient synthetic method of starch/lactic acid graft copolymer ...

    Indian Academy of Sciences (India)

    Copolymer of starch grafted with lactic acid (LA) could be directly prepared by reaction of cornstarch with lactic acid and with sodium hydroxide (NaOH) as the catalyst. The structure of starch/LA copolymer was characterized by IR, XRD, SEM and 1H-NMR. The effects of NaOH concentration, ratios of starch and LA, reaction ...

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

    International Nuclear Information System (INIS)

    Mackey, W.C.; Connolly, R.J.; Callow, A.D.

    1984-01-01

    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

  1. The inflammatory cells in vascular graft anastomosis an electron microscopy study.

    Science.gov (United States)

    Skóra, Jan; Pupka, Artur

    2011-01-01

    In order to determine the processes arising during the healing in vascular grafts the following experiment was desinged in 16 dogs. The animals underwent implantation of unilateral bypass aorto-femoral (straight prosthesis from politetrafluoroethylrne--PTFE). After the 6 months all the animals sacrificed and vascular grafts were dissected and exam in electron microscopy. There were significant differences in the histological findings in structure of neoitima between the proximal and distal anastomoses vascular prostheses. There were evidence of presence of fibroblasts but not macrophages in proximal anastomoses The histological structure of the proximal anastomoses indicates that inflammatory processes was ended during the prosthesis healing. There were presence of macrophages and myofibroblasts, some in the active secretion of collagen in distal anastomoses. Theses images of vascular anastomoses of artery with politerafluoroeth-ylene prosthesis corresponds to the chronic inflammatory reaction in distal anastomoses.

  2. 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.

  3. Free Vascularized Fibular Grafting Improves Vascularity Compared With Core Decompression in Femoral Head Osteonecrosis: A Randomized Clinical Trial.

    Science.gov (United States)

    Cao, Lu; Guo, Changan; Chen, Jifei; Chen, Zenggan; Yan, Zuoqin

    2017-09-01

    Management of osteonecrosis of the femoral head remains challenging. Core decompression and free vascularized fibular grafting are commonly used surgical procedures for treatment of osteonecrosis of the femoral head. Few studies, however, have compared these two procedures in a randomized controlled study, in terms of improved vascularity of the femoral head, progression of disease, or hip scores. QUESTION/PURPOSES: (1) What is the effect of core decompression and fibular grafting on vascularity of the femoral head as measured by single-photon emission CT (SPECT)/CT? (2) Does one of these two methods lead to greater progression of Association Research Circulation Osseous (ARCO) stage as determined by serial MRI? (3) What is the relationship between the change in vascularity of the femoral head and hip function as measured by the Harris hip score (HHS) and progression to THA as an endpoint? A randomized controlled trial was performed between June 2010 and October 2012 at Zhongshan Hospital, Fudan University. During the study period, 51 patients who presented with ARCO Stages I to IIIB bilateral osteonecrosis were potentially eligible for inclusion, and 33 patients were identified as meeting the inclusion criteria and offered enrollment and randomization. Six patients declined to participate at the time of randomization, leaving a final sample of 27 participants (54 hips). Bilateral hips of each patient were randomly assigned to surgical options: one side was treated with core decompression and the contralateral side was concurrently treated with fibular grafting. SPECT/CT examinations were performed to quantify radionuclide uptake to evaluate vascularity of the femoral head before treatment and at 6 and 36 months after surgery. With the numbers available, we found no differences between the groups regarding vascularity at baseline (64% ± 8% core decompression-treated hips versus 64% ± 7% in the fibular-grafted hips; 95% CI, -5% to 5%; p = 0.90). MR images of the

  4. 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

  5. Repair of bile duct injuries with Gore-Tex vascular grafts: experimental study in dogs.

    Science.gov (United States)

    Gómez, Néstor A; Alvarez, Ludwig R; Mite, Alfredo; Andrade, Jean P; Alvarez, José R; Vargas, Paola E; Tomalá, Nancy E; Vivas, Alex F; Zapatier, Jorge A

    2002-01-01

    Bile duct injury is the most feared complication related to biliary tract operations. The goal of this investigation was to offer an alternative treatment that might prevent this complication. Twelve mongrel dogs, thin-walled FEP-ringed Gore-Tex vascular grafts, and Gore-Tex sutures were used in this study. The dogs were randomized into three groups of four according to the length of time of graft implantation: group 1 = 1 month; group 2 = 2 months; and group 3 = 3 months. During the first part of the study, a biliary injury was induced by ligating the middle choledocus after performing a conventional cholecystectomy. During the second part of the study, biliodigestive and biliobiliary anastomosis were performed using Gore-Tex vascular grafts prior to resection of the stenotic area. Initially, an increase in serum bilirubin and alkaline phosphatase levels was noted. Two weeks later, after implantation of the grafts, these values returned to normal. Thin-walled FEP-ringed Gore-Tex vascular grafts were found to be useful in the repair of bile duct injuries, especially in complete transections of the common bile duct. The ductility and flexibility of the material allows any type of anastomosis to be performed, especially when bile duct-gut anastomosis is technically difficult.

  6. 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...

  7. A capsular-based vascularized distal radius graft for proximal pole scaphoid pseudarthrosis.

    Science.gov (United States)

    Sotereanos, Dean G; Darlis, Nickolaos A; Dailiana, Zoe H; Sarris, Ioannis K; Malizos, Konstantinos N

    2006-04-01

    To evaluate the clinical results of the application of a capsular-based dorsal distal radius vascularized bone graft in scaphoid proximal pole nonunions. Thirteen patients with symptomatic nonunion at the proximal pole of the scaphoid (10 with avascular necrosis) were treated and reviewed retrospectively. The vascularized bone graft was harvested from the distal aspect of the dorsal radius and was attached to a wide distally based strip of the dorsal wrist capsule. It was inserted press-fit into a dorsal trough across the nonunion site after scaphoid fixation with a Herbert screw. After a mean follow-up period of 19 months 10 of the 13 nonunions (8 of the 10 with avascular necrosis) achieved solid bone union. No complications other than the 3 persistent nonunions occurred. Results of the use of a capsular-based vascularized bone graft from the distal radius for proximal pole scaphoid nonunions compare favorably with the results of pedicled or free vascularized grafts. It is a simple technique that eliminates the need for dissection of small-caliber pedicle or microsurgical anastomoses. No donor site morbidity was observed. Therapeutic, Level IV.

  8. 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.

  9. 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.

  10. 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 < 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.

  11. Morphometric analysis of bone vascular channels during the biointegration of autologous bone grafts.

    Science.gov (United States)

    Petrescu, H P; Dinu, G; Nodiţi, G; Craina, M; Berceanu-Văduva, Delia; Berceanu-Văduva, M; Vermeşan, D

    2013-01-01

    Vascularization of the transplanted bone tissue is a key factor for success and precedes the formation of bone tissue. Vascularized bone grafts have been widely used in bone transplantation for their efficiency. Maturation of the bone tissue at the place of the transplant involves the change in the vascular patterning, from plexiform irregular vascular networks, to regular, polygonal networks following the structure of osteons. Seven dogs were performed bone transplantation and intravenous injection with China ink in order to highlight the network of blood vessels during bone formation at the place of the transplant. The area occupied by blood vessels increased during osteogenesis, and their length decreased in evolution, suggesting a maturation of the vascular pattern.

  12. Enzyme-functionalized vascular grafts catalyze in-situ release of nitric oxide from exogenous NO prodrug.

    Science.gov (United States)

    Wang, Zhihong; Lu, Yaxin; Qin, Kang; Wu, Yifan; Tian, Yingping; Wang, Jianing; Zhang, Jimin; Hou, Jingli; Cui, Yun; Wang, Kai; Shen, Jie; Xu, Qingbo; Kong, Deling; Zhao, Qiang

    2015-07-28

    Nitric oxide (NO) is an important signaling molecule in cardiovascular system, and the sustained release of NO by endothelial cells plays a vital role in maintaining patency and homeostasis. In contrast, lack of endogenous NO in artificial blood vessel is believed to be the main cause of thrombus formation. In this study, enzyme prodrug therapy (EPT) technique was employed to construct a functional vascular graft by immobilization of galactosidase on the graft surface. The enzyme-functionalized grafts exhibited excellent catalytic property in decomposition of the exogenously administrated NO prodrug. Localized and on-demand release of NO was demonstrated by in vitro release assay and fluorescent probe tracing in an ex vivo model. The immobilized enzyme retained catalytic property even after subcutaneous implantation of the grafts for one month. The functional vascular grafts were implanted into the rat abdominal aorta with a 1-month monitoring period. Results showed effective inhibition of thrombus formation in vivo and enhancement of vascular tissue regeneration and remodeling on the grafts. Thus, we create an enzyme-functionalized vascular graft that can catalyze prodrug to release NO locally and sustainably, indicating that this approach may be useful to develop new cell-free vascular grafts for treatment of vascular diseases. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. 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 NH 3 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.

  14. 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.

  15. Improvement of cell infiltration in electrospun polycaprolactone scaffolds for the construction of vascular grafts.

    Science.gov (United States)

    Wang, Kai; Zhu, Meifeng; Li, Ting; Zheng, Wenting; Li, Li; Xu, Mian; Zhao, Qiang; Kong, Deling; Wang, Lianyong

    2014-08-01

    The less-than-ideal cell infiltration resulting from inherently small pore size limits the application of electrospinning scaffold in tissue engineering and regeneration medicine. The present study aims to develop a porogenic method which can significantly increase pore size in electrospinning scaffold and enhance cell migration. With this method, composite scaffolds consisting of poly(epsilon-caprolactone) (PCL) fibers and poly(ethylene oxide) (PEO) microparticles were prepared by simultaneously electrospinning and electrospraying. Removal of the PEO microparticles from the composites generated large pores. In vitro culture of NIH3T3 cells and in vivo subcutaneous implantation both demonstrated that the porogenic scaffolds markedly facilitated cell infiltration. With the same technique, vascular grafts with alternative dense and loose layers were prepared by turning on or off electrospraying PEO. SEM showed that there was no a clear delamination between the loose and dense layers. The mechanical strength and burst pressure of these vascular grafts could meet the requirements of vascular implantation. In conclusion, electrospinning PCL fibers with electrospraying PEO microparticles may be an effective and controllable method to increase pore size in electrospinning scaffold and provides a useful tool for the fabrication of vascular grafts that meets the need of blood vessel replacement.

  16. The manufacture of synthetic non-sintered and degradable bone grafting substitutes.

    Science.gov (United States)

    Gerike, W; Bienengräber, V; Henkel, K-O; Bayerlein, T; Proff, P; Gedrange, T; Gerber, Th

    2006-02-01

    A new synthetic bone grafting substitute (NanoBone, ARTOSS GmbH, Germany) is presented. This is produced by a new technique, the sol-gel-method. This bone grafting substitute consists of nanocrystalline hydroxyapatite (HA) and nanostructured silica (SiO2). By achieving a highly porous structure good osteoconductivity can be seen. In addition, the material will be completely biodegraded and new own bone is formed. It has been demonstrated that NanoBone is biodegraded by osteoclasts in a manner comparable to the natural bone remodelling process.

  17. Tuberculous Aortic Pseudoaneurysm Treated with In Situ Silver-impregnated Vascular Inlay Graft

    Directory of Open Access Journals (Sweden)

    Hanif Hussein

    2008-04-01

    Full Text Available A 62-year-old man presented with continuous, persistent backache shortly after completion of anti-tuberculosis medication for tuberculosis (TB of the spine. Computed tomography scan revealed a pseudoaneurysm involving the infrarenal aorta. He was restarted on anti-TB medication and underwent repair of the pseudoaneurysm with an in situ silver-coated bifurcated Dacron graft. His postoperative recovery was uneventful and he remained well up to 12 months of follow up. To our knowledge, this is the first case in the literature where an in situ silver-impregnated vascular graft has been successfully used in treating a tuberculous pseudoaneurysm.

  18. Rapid in Vitro Quantification of S. aureus Biofilms on Vascular Graft Surfaces

    Directory of Open Access Journals (Sweden)

    Monika Herten

    2017-12-01

    Full Text Available Objectives: Increasing resistance of microorganisms and particularly tolerance of bacterial biofilms against antibiotics require the need for alternative antimicrobial substances. S. aureus is the most frequent pathogen causing vascular graft infections. In order to evaluate the antimicrobial efficacy, quantification of the bacterial biofilms is necessary. Aim of the present study was the validation of an in vitro model for quantification of bacterial biofilm on vascular graft surfaces using three different assays.Methods: Standardized discs of vascular graft material (Dacron or PTFE or polystyrene (PS as control surface with 0.25 cm2 surface area were inoculated with 10−3 diluted overnight culture of three biofilm-producing S. aureus isolates (BEB-029, BEB-295, SH1000 in 96-well PS culture plates. After incubation for 4 and 18 h, the biofilm was determined by three different methods: (a mitochondrial ATP concentration as measure of bacterial viability (ATP, (b crystal violet staining (Cry, and (c vital cell count by calculation of colony-forming units (CFU. The experiments were performed three times. Quadruplicates were used for each isolate, time point, and method. In parallel, bacterial biofilms were documented via scanning electron microscopy.Results: All three methods could quantify biofilms on the PS control. Time needed was 0:40, 13:10, and 14:30 h for ATP, Cry, and CFU, respectively. The Cry assay could not be used for vascular graft surfaces due to high unspecific background staining. However, ATP assay and CFU count showed comparable results on vascular graft material and control. The correlations between ATP and CFU assay differed according to the surface and incubation time and were significant only after 4 h on Dacron (BEB-029, p = 0.013 and on PS (BEB-029, p < 0.001. Between ATP and Cry assay on PS, a significant correlation could be detected after 4 h (BEB-295, p = 0.027 and after 18 h (all three strains, p < 0.026. The

  19. Quantification of deposition of neutrophilic granulocytes on vascular grafts in dogs with 111In-labeled granulocytes

    International Nuclear Information System (INIS)

    Dewanjee, M.K.; Solis, E.; Mackey, S.T.; Socher, S.; Chowdhury, S.; Wu, F.P.; Kaye, M.P.

    1985-01-01

    A new radioisotopic technique has been developed for quantification of deposition of neutrophilic granulocytes on vascular grafts. Nine healthy mongrel dogs underwent bilateral femoral artery resection and reconstruction with grafts of the femoral vein and Gore-Tex. Pure granulocytes that had been separated from whole blood by centrifugal elutriation were labeled with 111 In-tropolone in plasma. The granulocyte harvesting efficiency was 25 +/- 12%, and the labeling efficiency was 87 +/- 7%. Three hours after injection of labeled granulocytes and 2 hours after reperfusion, the grafts were harvested and cut into several segments for study of areas of anastomoses and midsections. On the basis of the radioactivity in the blood and in anastomotic and graft sections, the area of graft sections, and the neutrophilic granulocyte and differential leukocyte counts, the number of neutrophilic granulocytes adherent to a unit area and the total number of neutrophilic granulocytes on graft sections were calculated. These quantifications of the deposition of neutrophilic granulocytes indicated that the midsections of Gore-Tex grafts retained more neutrophilic granulocytes than did the midsections of vein grafts. Although the anastomotic areas retained more neutrophilic granulocytes than did the midsections of vein grafts, the opposite finding prevailed for the Gore-Tex grafts. A major fraction of neutrophilic granulocytes on Gore-Tex grafts was incorporated into the thrombus. Semiquantitative information obtained by scintigraphy of the deposition of neutrophilic granulocytes on vascular grafts also confirmed this observation

  20. Vascularized bone graft in scaphoid fractures. Anatomical details and clinical indications. A cases series

    International Nuclear Information System (INIS)

    Vergara A, Enrique

    2007-01-01

    The fracture of scaphoid continues being a challenge for orthopedist and hand surgeons. Objective. To show the anatomical details of the bony strip from the second metacarpal in corpses injected with green latex and the results of the surgical technique in a series of patients with scaphoid pseudarthrosis. Materials and methods. We carry out an initial anatomical analysis before employing the surgical technique in clinical setting, and then we did a descriptive study of patients with pseudarthrosis of scaphoid,treated with vascularized bony graft by the first metacarpal artery. Results. All patients consolidated and improved in the pain scale, they did not have mobility deterioration or residual carpus instability, after ten years of observations. Conclusions. The vascularized graft is a useful option in the management of the pseudarthrosis of the scaphoid.

  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......'s sarcoma had an early hip disarticulation, developed multiple metastases, and died 9 months after the operation. The remaining patients (n = 7) are all alive 50 months (range 26-75 months) after surgery. During the follow-up the following major complications were seen: 1-2 fractures (n = 4), pseudarthrosis...... (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. Prefabrication of a vascularized nerve graft by vessel implantation: preliminary report of an experimental model.

    Science.gov (United States)

    Cavadas, P C; Vera-Sempere, F J

    1994-01-01

    Regeneration through vascularized nerve grafts (VNG) seems to be better than nonvascularized nerve grafts (NVNG), especially in hostile beds. We report on an experimental technique of prefabrication of VNG by direct vessel implantation. An arteriovenous fistula was created in the groin region with autologous vein grafts in the Wistar rat model, and implanted into the sciatic nerve. Five weeks later the sciatic VNG was elevated on the prefabricated pedicle. The flap was free-transferred orthotopically over a silicone sheet to impede plasmatic imbibition. Flap viability at 3 days was complete. India ink injection of the AV fistula resulted in capillary ink filling within the nerve and surrounding tissues. Histologic sections of the flap were examined, revealing its neovascularity. In an ongoing study, the regeneration through this prefabricated VNG is being compared to native VNG.

  3. 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

    with anastomotic pseudoaneurysms without leak, of which three had proximal anastomotic pseudoaneurysms and one had distal iliac anastomotic pseudoaneurysm. Implanted stent graft were Endurant (Medtronic) bifurcated endoprostheses in three patients and Excluder (Gore) prosthesis in a two cases. Tubular Medtronic...... 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......-36 months) in the other 9 patients. There were no complications like endoleaks or limb occlusions. CONCLUSION: Endovascular treatment of vascular graft related postsurgical complications is a valuable therapeutic option followed by lower mortality and morbidity rates compared with re-operation. Short...

  4. Reconstruction of scaphoid nonunion fractures of the proximal one third with a vascularized bone graft from the distal radius.

    Science.gov (United States)

    Werdin, Frank; Jaminet, Patrick; Naegele, Beate; Pfau, Matthias; Schaller, Hans-Eberhard

    2014-01-01

    The treatment of proximal located scaphoid nonunion is a well-known and common problem. For these patients, we used a vascular pedicled bone graft of the distal radius. In the last 7 years, 75 patients were treated with the vascular pedicled bone graft. Retrospectively, patients' data, healing rates, and factors influencing scaphoid healing were analyzed. The overall healing rate in cases with proximal located nonunions (n = 54) was approximately 70%. Out of these 54 patients, 47 patients showed avascular proximal fragments. Multivariate analysis showed no significant impact for the factors age, smoking, duration of disease, or previous operation. In our negative selected patient group, we were able to achieve good results with the usage of a pedicled vascularized bone graft of the distal radius. Our results indicate a favorable outcome for the use of a pedicled vascularized distal radius bone graft in both scaphoid nonunion fractures of the proximal third, with or without an avascular proximal pole.

  5. Anterior cruciate ligament reconstruction with synthetic grafts. A review of literature

    Science.gov (United States)

    Ventura, Alberto; Terzaghi, Clara; Borgo, Enrico; Albisetti, Walter

    2010-01-01

    Anterior cruciate ligament (ACL) rupture, one of the most common knee injuries in sports, results in anteroposterior laxity, which often leads to an unstable knee. Traditional ACL reconstruction is performed with autograft; disadvantages of this technique are donor site morbidity and a long rehabilitation period. In the 1980s, artificial ligaments became an attractive alternative to biological grafts. The initial enthusiasm surrounding their introduction stemmed from their lack of donor morbidity, their abundant supply and significant strength, immediate loading and reduced postoperative rehabilitation. Synthetic grafts made of different materials such as carbon fibers, polypropylene, Dacron and polyester have been utilised either as a prosthesis or as an augmentation for a biological ACL graft substitute. Nevertheless, every material presented serious drawbacks: cross-infections, immunological responses, breakage, debris dispersion leading to synovitis, chronic effusions, recurrent instability and knee osteoarthritis. Recently, a resurgence of interest in the use of synthetic prostheses has occurred and studies regarding new artificial grafts have been reported. Although many experimental studies have been made and much effort has been put forth, currently no ideal prosthesis mimicking natural human tissue has been found. PMID:20157811

  6. Construction of tissue-engineered small-diameter vascular grafts in fibrin scaffolds in 30 days.

    Science.gov (United States)

    Gui, Liqiong; Boyle, Michael J; Kamin, Yishai M; Huang, Angela H; Starcher, Barry C; Miller, Cheryl A; Vishnevetsky, Michael J; Niklason, Laura E

    2014-05-01

    Tissue-engineered small-diameter vascular grafts have been developed as a promising alternative to native veins or arteries for replacement therapy. However, there is still a crucial need to improve the current approaches to render the tissue-engineered blood vessels more favorable for clinical applications. A completely biological blood vessel (3-mm inner diameter) was constructed by culturing a 50:50 mixture of bovine smooth muscle cells (SMCs) with neonatal human dermal fibroblasts in fibrin gels. After 30 days of culture under pulsatile stretching, the engineered blood vessels demonstrated an average burst pressure of 913.3±150.1 mmHg (n=6), a suture retention (53.3±15.4 g) that is suitable for implantation, and a compliance (3.1%±2.5% per 100 mmHg) that is comparable to native vessels. These engineered grafts contained circumferentially aligned collagen fibers, microfibrils and elastic fibers, and differentiated SMCs, mimicking a native artery. These promising mechanical and biochemical properties were achieved in a very short culture time of 30 days, suggesting the potential of co-culturing SMCs with fibroblasts in fibrin gels to generate functional small-diameter vascular grafts for vascular reconstruction surgery.

  7. Prosthetic vascular graft infection and prosthetic joint infection caused byPseudomonas stutzeri.

    Science.gov (United States)

    Bonares, Michael J; Vaisman, Alon; Sharkawy, Abdu

    2016-01-01

    Pseudomonas stutzeri is infrequently isolated from clinical specimens, and if isolated, more likely represents colonization or contamination rather than infection. Despite this, there are dozens of case reports which describe clinically significant P. stutzeri infections at variable sites. A 69-year-old man had a P. stutzeri infection of a prosthetic vascular graft infection, which he received in Panama City. He was successfully treated with a single antipseudomonal agent for 6 weeks and the removal of the infected vascular graft. A 70-year-old man had a P. stutzeri infection of a prosthetic joint, which was successfully treated with a single anti-pseudomonal agent for 6 weeks. There is only one other documented case of a prosthetic vascular graft infection secondary to P. stutzeri . There are 5 documented cases of P. stutzeri prosthetic joint infections. The previous cases were treated with antibiotics and variably, source control with the removal of prosthetic material. Most cases of P. stutzeri infection are due to exposure in health care settings. Immunocompromised states such as HIV or hematological and solid tumor malignancies are risk factors for P. stutzeri infection. Infections caused by P. stutzeri are far less frequent and less fatal than those caused by P. aeruginosa. The etiology of a P. stutzeri infection could be exposure to soil and water, but also contaminated material in the health care setting or an immunocompromised state. Iatrogenic infections that are secondary to health care tourism are a potential cause of fever in the returned traveler.

  8. Scaling of Engineered Vascular Grafts Using 3D Printed Guides and the Ring Stacking Method.

    Science.gov (United States)

    Pinnock, Cameron B; Xu, Zhengfan; Lam, Mai T

    2017-03-27

    Coronary artery disease remains a leading cause of death, affecting millions of Americans. With the lack of autologous vascular grafts available, engineered grafts offer great potential for patient treatment. However, engineered vascular grafts are generally not easily scalable, requiring manufacture of custom molds or polymer tubes in order to customize to different sizes, constituting a time-consuming and costly practice. Human arteries range in lumen diameter from about 2.0-38 mm and in wall thickness from about 0.5-2.5 mm. We have created a method, termed the "Ring Stacking Method," in which variable size rings of tissue of the desired cell type, demonstrated here with vascular smooth muscle cells (SMCs), can be created using guides of center posts to control lumen diameter and outer shells to dictate vessel wall thickness. These tissue rings are then stacked to create a tubular construct, mimicking the natural form of a blood vessel. The vessel length can be tailored by simply stacking the number of rings required to constitute the length needed. With our technique, tissues of tubular forms, similar to a blood vessel, can be readily manufactured in a variety of dimensions and lengths to meet the needs of the clinic and patient.

  9. In Vitro Endothelialization of Biodegradable Vascular Grafts Via Endothelial Progenitor Cell Seeding and Maturation in a Tubular Perfusion System Bioreactor

    OpenAIRE

    Melchiorri, Anthony J.; Bracaglia, Laura G.; Kimerer, Lucas K.; Hibino, Narutoshi; Fisher, John P.

    2016-01-01

    A critical challenge to the success of biodegradable vascular grafts is the establishment of a healthy endothelium. To establish this monolayer of endothelial cells (ECs), a variety of techniques have been developed, including cell seeding. Vascular grafts may be seeded with relevant cell types and allowed to mature before implantation. Due to the low proliferative ability of adult ECs and issues with donor site morbidity, there has been increasing interest in using endothelial progenitor cel...

  10. Reconstruction of Scaphoid Nonunion Fractures of the Proximal One Third With a Vascularized Bone Graft From the Distal Radius

    OpenAIRE

    Werdin, Frank; Jaminet, Patrick; Naegele, Beate; Pfau, Matthias; Schaller, Hans-Eberhard

    2014-01-01

    Objective: The treatment of proximal located scaphoid nonunion is a well-known and common problem. For these patients, we used a vascular pedicled bone graft of the distal radius. Methods: In the last 7 years, 75 patients were treated with the vascular pedicled bone graft. Retrospectively, patients’ data, healing rates, and factors influencing scaphoid healing were analyzed. Results: The overall healing rate in cases with proximal located nonunions (n = 54) was approximately 70%. Out of these...

  11. Mechanical property characterization of electrospun recombinant human tropoelastin for vascular graft biomaterials.

    Science.gov (United States)

    McKenna, Kathryn A; Hinds, Monica T; Sarao, Rebecca C; Wu, Ping-Cheng; Maslen, Cheryl L; Glanville, Robert W; Babcock, Darcie; Gregory, Kenton W

    2012-01-01

    The development of vascular grafts has focused on finding a biomaterial that is non-thrombogenic, minimizes intimal hyperplasia, matches the mechanical properties of native vessels and allows for regeneration of arterial tissue. In this study, the structural and mechanical properties and the vascular cell compatibility of electrospun recombinant human tropoelastin (rTE) were evaluated as a potential vascular graft support matrix. Disuccinimidyl suberate (DSS) was used to cross-link electrospun rTE fibers to produce a polymeric recombinant tropoelastin (prTE) matrix that is stable in aqueous environments. Tubular 1cm diameter prTE samples were constructed for uniaxial tensile testing and 4mm small-diameter prTE tubular scaffolds were produced for burst pressure and cell compatibility evaluations from 15 wt.% rTE solutions. Uniaxial tensile tests demonstrated an average ultimate tensile strength (UTS) of 0.36±0.05 MPa and elastic moduli of 0.15±0.04 and 0.91±0.16 MPa, which were comparable to extracted native elastin. Burst pressures of 485±25 mm Hg were obtained from 4mm internal diameter scaffolds with 453±74 μm average wall thickness. prTE supported endothelial cell growth with typical endothelial cell cobblestone morphology after 48 h in culture. Cross-linked electrospun rTE has promising properties for utilization as a vascular graft biomaterial with customizable dimensions, a compliant matrix and vascular cell compatibility. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  12. 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.

  13. GORE-TEX VASCULAR GRAFT FOR MACULAR BUCKLING IN HIGH MYOPIA EYES.

    Science.gov (United States)

    Wu, Pei-Chang; Sheu, Jiunn-Jye; Chen, Yi-Hao; Chen, Yung-Jen; Chen, Chih-Hsin; Lee, Jong-Jer; Huang, Chih-Ling; Chen, Chueh-Tan; Kuo, Hsi-Kung

    2017-07-01

    To evaluate a new application of an expanded polytetrafluoroethylene (Gore-Tex) vascular graft for use in macular buckling surgery for treatment of highly myopic eyes. The Gore-Tex vascular graft was used as a macular buckling material in eight consecutive cases of myopic macular diseases which included fovea detachment, foveoschisis, or macular hole retinal detachment. Retinal reattachment was achieved in all cases except one which had partial resolution (88%). The postoperative best-corrected visual acuity ranged from 20/2000 to 20/100 depending on the degree preexisting macular degeneration, and significant better than the preoperative best-corrected visual acuity (P = 0.048, paired t-test). During the follow-up period, which ranged from 8 months to 3 years, no eye developed buckle-related complications such as infection or dislocation. The initial pilot results from this series using a Gore-Tex graft for macular buckling is promising. Throughout the follow-up period, the Gore-Tex was well tolerated in the highly myopic eyes. Large scale and long-term follow-up is warranted.

  14. The vacuum-assisted closure (V.A.C®) system for surgical site infection with involved vascular grafts.

    Science.gov (United States)

    Saziye, Karaca; Afksendiyos, Kalangos

    2015-04-01

    In vascular surgery, surgical site infection is the most common postoperative morbidity, occurring in 5-10% of vascular patients. The optimal management of surgical site infection with involved lower limb vascular grafts remains controversial. We present our 6-year results of using the V.A.C.® system in surgical site infection with involved vascular grafts. A retrospective 6-year review of patient who underwent a VAC® therapy for postoperative surgical site infection in lower limb with involved vascular grafts in our department between January 2006 and December 2011. V.A.C therapy was used in 40 patients. All patients underwent surgical wound revision with VAC® therapy and antibiotics. The mean time of use of the V.A.C. system was 14.2 days. After mean of 12 days in 34 of 40 patients, in whom the use of VAC® therapy resulted in delayed primary closure or healing by secondary intention. The mean postoperative follow-up time was 61.67 months, during which 3 patients died. We showed that the V.A.C.® system is valuable for managing specifically surgical site infection with involved vascular grafts. Using the V.A.C.® system, reoperation rates are reduced; 85% of patients avoided graft replacement. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  15. 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

    with anastomotic pseudoaneurysms without leak, of which three had proximal anastomotic pseudoaneurysms and one had distal iliac anastomotic pseudoaneurysm. Implanted stent graft were Endurant (Medtronic) bifurcated endoprostheses in three patients and Excluder (Gore) prosthesis in a two cases. Tubular Medtronic....... The mortality and morbidity is higher compared to the initial treatment. We present twelve patients with these complications which were treated by an endovascular approach. METHODS: From January 2008 through January 2013 our radiological records were searched for cases with post surgical vascular complications...... treated with endovascular intervention. These comprised of anastomotic pseudoaneurysm, suture leakage and arterial enteric fistulas. Patients with limb occlusions were not included in this study. RESULTS: Twelve patients with graft related complications treated with endovascular intervention were recorded...

  16. Computationally Optimizing the Compliance of a Biopolymer Based Tissue Engineered Vascular Graft.

    Science.gov (United States)

    Harrison, Scott; Tamimi, Ehab; Uhlorn, Josh; Leach, Tim; Vande Geest, Jonathan P

    2016-01-01

    Coronary heart disease is a leading cause of death among Americans for which coronary artery bypass graft (CABG) surgery is a standard surgical treatment. The success of CABG surgery is impaired by a compliance mismatch between vascular grafts and native vessels. Tissue engineered vascular grafts (TEVGs) have the potential to be compliance matched and thereby reduce the risk of graft failure. Glutaraldehyde (GLUT) vapor-crosslinked gelatin/fibrinogen constructs were fabricated and mechanically tested in a previous study by our research group at 2, 8, and 24 hrs of GLUT vapor exposure. The current study details a computational method that was developed to predict the material properties of our constructs for crosslinking times between 2 and 24 hrs by interpolating the 2, 8, and 24 hrs crosslinking time data. matlab and abaqus were used to determine the optimal combination of fabrication parameters to produce a compliance matched construct. The validity of the method was tested by creating a 16-hr crosslinked construct of 130 μm thickness and comparing its compliance to that predicted by the optimization algorithm. The predicted compliance of the 16-hr construct was 0.00059 mm Hg-1 while the experimentally determined compliance was 0.00065 mm Hg-1, a relative difference of 9.2%. Prior data in our laboratory has shown the compliance of the left anterior descending porcine coronary (LADC) artery to be 0.00071 ± 0.0003 mm Hg-1. Our optimization algorithm predicts that a 258-μm-thick construct that is GLUT vapor crosslinked for 8.1 hrs would match LADC compliance. This result is consistent with our previous work demonstrating that an 8-hr GLUT vapor crosslinked construct produces a compliance that is not significantly different from a porcine coronary LADC.

  17. Effects of Ischemic Preconditioning of Different Intraoperative Ischemic Times of Vascularized Bone Graft Rabbit Models

    Directory of Open Access Journals (Sweden)

    Ahmad Sukari Halim

    2013-11-01

    Full Text Available BackgroundIschemic preconditioning has been shown to improve the outcomes of hypoxic tolerance of the heart, brain, lung, liver, jejunum, skin, and muscle tissues. However, to date, no report of ischemic preconditioning on vascularized bone grafts has been published.MethodsSixteen rabbits were divided into four groups with ischemic times of 2, 6, 14, and 18 hours. Half of the rabbits in each group underwent ischemic preconditioning. The osteomyocutaneous flaps consisted of the tibia bone, from which the overlying muscle and skin were raised. The technique of ischemic preconditioning involved applying a vascular clamp to the pedicle for 3 cycles of 10 minutes each. The rabbits then underwent serial plain radiography and computed tomography imaging on the first, second, fourth, and sixth postoperative weeks. Following this, all of the rabbits were sacrificed and histological examinations were performed.ResultsThe results showed that for clinical analysis of the skin flaps and bone grafts, the preconditioned groups showed better survivability. In the plain radiographs, except for two non-preconditioned rabbits with intraoperative ischemic times of 6 hours, all began to show early callus formation at the fourth week. The computed tomography findings showed more callus formation in the preconditioned groups for all of the ischemic times except for the 18-hour group. The histological findings correlated with the radiological findings. There was no statistical significance in the difference between the two groups.ConclusionsIn conclusion, ischemic preconditioning improved the survivability of skin flaps and increased callus formation during the healing process of vascularized bone grafts.

  18. Experimental study of vascularized nerve graft: evaluation of nerve regeneration using choline acetyltransferase activity.

    Science.gov (United States)

    Iwai, M; Tamai, S; Yajima, H; Kawanishi, K

    2001-01-01

    A comparative study of nerve regeneration was performed on vascularized nerve graft (VNG) and free nerve graft (FNG) in Fischer strain rats. A segment of the sciatic nerve with vascular pedicle of the femoral artery and vein was harvested from syngeneic donor rat for the VNG group and the sciatic nerve in the same length without vascular pedicle was harvested for the FNG group. They were transplanted to a nerve defect in the sciatic nerve of syngeneic recipient rats. At 2, 4, 6, 8, 12, 16, and 24 weeks after operation, the sciatic nerves were biopsied and processed for evaluation of choline acetyltransferase (CAT) activity, histological studies, and measurement of wet weight of the muscle innervated by the sciatic nerve. Electrophysiological evaluation of the grafted nerve was also performed before sacrifice. The average CAT activity in the distal to the distal suture site was 383 cpm in VNG and 361 cpm in FNG at 2 weeks; 6,189 cpm in VNG and 2,264 cpm in FNG at 4 weeks; and 11,299 cpm in VNG and 9,424 cpm in FNG at 6 weeks postoperatively. The value of the VNG group was statistically higher than that of the FNG group at 4 weeks postoperatively. Electrophysiological and histological findings also suggested that nerve regeneration in the VNG group was superior to that in the FNG group during the same period. However, there was no significant difference between the two groups after 6 weeks postoperatively in any of the evaluations. The CAT measurement was useful in the experiments, because it was highly sensitive and reproducible. Copyright 2001 Wiley-Liss, Inc.

  19. Continuous betadine-bacitracin irrigation for vascular graft infections: A case series.

    Science.gov (United States)

    Strider, David V; Ratliff, Catherine R; Cherry, Kenneth J; Upchurch, Gilbert R

    2018-03-01

    The aim of the study was to conduct a retrospective chart review of patients who underwent betadine/bacitracin continuous irrigation (BBCI) for vascular graft infections (VGIs) to review its use as a treatment option. A retrospective chart review from 2013 to 2017 was conducted of patients with VGIs that were treated with BBCI postremoval of the infected graft. The BBCI is a continuous infusion of 0.25% betadine in normal saline at 0.3 mL/kg/h for 48 hours then followed by bacitracin infusion with a concentration of 50,000 units bacitracin/per liter normal saline at 0.3 mL/kg/h for 72 hours. Descriptive statistics were used to describe the sample. The nine adult patients who received postoperative BBCI had an age range of 30-81 years, with average age of 58.8 years. Five of the subjects were females with four males. A total of nine patients with groin infections were identified, with two aortobifemoral bypasses, two axillofemoral bypasses, three femoral-femoral bypasses, one femoral artery pseudoaneurysm repair with Dacron patch, and one common femoral endarterectomy with Dacron patch. VGIs were identified from 10 days up to 72 months from the original vascular procedure. Six patients had negative wound cultures, while two had wound cultures positive for methicillin-resistant Staphylococcus aureus and one patient had positive culture for Escherichia coli. The length of time of BBCI ranged from 48 to 84 hours with average of 57.6 hours (standard deviation [SD] = 12.7 hours). The length of time of the bacitracin irrigation ranged from 30 to 72 hours with average of 48.4 hours (SD = 14.9 hours). All patients healed their groin wounds except for an 81-year-old patient with aortobifemoral bypass graft who developed ischemic bowel and expired. Patients received at least 6 weeks of intravenous antibiotics followed by oral antibiotic suppression therapy for life. VGIs are a devastating complication associated with a high morbidity. BBCI provides an option

  20. Tissue engineered vascular grafts: Origins, development, and current strategies for clinical application.

    Science.gov (United States)

    Benrashid, Ehsan; McCoy, Christopher C; Youngwirth, Linda M; Kim, Jina; Manson, Roberto J; Otto, James C; Lawson, Jeffrey H

    2016-04-15

    Since the development of a dependable and durable synthetic non-autogenous vascular conduit in the mid-twentieth century, the field of vascular surgery has experienced tremendous growth. Concomitant with this growth, development in the field of bioengineering and the development of different tissue engineering techniques have expanded the armamentarium of the surgeon for treating a variety of complex cardiovascular diseases. The recent development of completely tissue engineered vascular conduits that can be implanted for clinical application is a particularly exciting development in this field. With the rapid advances in the field of tissue engineering, the great hope of the surgeon remains that this conduit will function like a true blood vessel with an intact endothelial layer, with the ability to respond to endogenous vasoactive compounds. Eventually, these engineered tissues may have the potential to supplant older organic but not truly biologic technologies, which are used currently. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Full-thickness skin graft vs. synthetic mesh in the repair of giant incisional hernia: a randomized controlled multicenter study.

    Science.gov (United States)

    Clay, L; Stark, B; Gunnarsson, U; Strigård, K

    2018-04-01

    Repair of large incisional hernias includes the implantation of a synthetic mesh, but this may lead to pain, stiffness, infection and enterocutaneous fistulae. Autologous full-thickness skin graft as on-lay reinforcement has been tested in eight high-risk patients in a proof-of-concept study, with satisfactory results. In this multicenter randomized study, the use of skin graft was compared to synthetic mesh in giant ventral hernia repair. Non-smoking patients with a ventral hernia > 10 cm wide were randomized to repair using an on-lay autologous full-thickness skin graft or a synthetic mesh. The primary endpoint was surgical site complications during the first 3 months. A secondary endpoint was patient comfort. Fifty-three patients were included. Clinical evaluation was performed at a 3-month follow-up appointment. There were fewer patients in the skin graft group reporting discomfort: 3 (13%) vs. 12 (43%) (p = 0.016). Skin graft patients had less pain and a better general improvement. No difference was seen regarding seroma; 13 (54%) vs. 13 (46%), or subcutaneous wound infection; 5 (20%) vs. 7 (25%). One recurrence appeared in each group. Three patients in the skin graft group and two in the synthetic mesh group were admitted to the intensive care unit. No difference was seen for the primary endpoint short-term surgical complication. Full-thickness skin graft appears to be a reliable material for ventral hernia repair producing no more complications than when using synthetic mesh. Patients repaired with a skin graft have less subjective abdominal wall symptoms.

  2. Inferior angle of the scapula as a vascularized bone graft: an anatomic study.

    Science.gov (United States)

    Sundine, M J; Sharobaro, V I; Ljubic, I; Acland, R D; Tobin, G R

    2000-04-01

    In reconstructing patients with massive midface losses, the authors required a vascularized bone graft that could be used to reconstruct the palate and orbital floor, provide vertical maxillary support, and provide soft tissue. The inferior angle of the scapula appears to be a promising source of vascularized bone stock, and until now, there has been no clear description of its vascular anatomy. The purpose of this study was to define the vascular anatomy of the inferior angle of the scapula. Thirteen fresh cadavers were studied. The subscapular artery was injected with Microfil (Flow Tec, Carver, MA) at its origin. Two branches of the subscapular artery were found to converge on the angle of the scapula: the descending osseous branch of the circumflex scapular, and the transverse branch of the thoracodorsal. The descending osseous branch of the circumflex scapular artery supplied the inferior angle of the scapula in 100 percent of cases. The transverse branch of the thoracodorsal artery supplied it in 76 percent of cases. The descending osseous branch of the circumflex scapular artery is the principal artery supplying the inferior angle of the scapula.

  3. 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.

  4. Femoral head bone viability after free vascularized fibular grafting for osteonecrosis: SPECT/CT study.

    Science.gov (United States)

    Fontecha, Cesar G; Roca, Isabel; Barber, Ignasi; Menendez, Mariano E; Collado, Diego; Mascarenhas, Vasco V; Barrera-Ochoa, Sergio; Soldado, Francisco

    2016-10-01

    To evaluate femoral head bone viability following free vascularized fibular grafting (FVFG) for osteonecrosis using SPECT/CT imaging. Ten hips (9 patients) with osteonecrosis of the femoral head (ONFH) undergoing FVFG were prospectively enrolled. Four cases showed ARCO stage II, while six showed ARCO stage III. The mean age at surgery was 15.7 years (range, 13-22 years). Hip Harris Score (HHS) was measured pre- and post-operative. Bone scintigraphy with SPECT/CT was performed at 2 weeks and 6 months following surgery. Mean follow-up was 4.0 years (range, 2-5.9 years). Mean HHS increased from 37.2 to 92.3. SPECT/CT findings revealed a progressive increase of femoral head uptake in all cases, suggesting subchondral graft bone viability. No progressive deformation of the femoral head was evidenced in radiographic evaluation at final follow-up. This study demonstrates FVFG's capacity for revitalizing femoral head subchondral bone grafting in patients with ONFH, surgically treated following Urbaniak's technique. © 2015 Wiley Periodicals, Inc. Microsurgery 36:573-577, 2016. © 2015 Wiley Periodicals, Inc.

  5. Treatment of avascular proximal pole scaphoid nonunions with vascularized distal radius bone grafting.

    Science.gov (United States)

    Lim, Tae Kang; Kim, Hyo Kon; Koh, Kyoung Hwan; Lee, Hyun Il; Woo, Sung Jong; Park, Min Jong

    2013-10-01

    To investigate the outcomes of vascularized distal radius pedicled bone grafting secured with K-wires for scaphoid nonunions with small avascular proximal fragments. We included patients with scaphoid nonunions and small, avascular proximal fragments that were too small for screw fixation. The mean size of the proximal pole fragments was 21% (range, 9% to 28%) of the entire scaphoid, based on quantitative radiographic measurement. All patients had distal radius bone grafting based on the 1,2-intercompartmental supraretinacular artery pedicle and fixation with K-wires. There were 21 wrists in 18 men and 2 women with the mean age of 34 years (range, 22 to 57 y). The mean duration of postoperative follow-up was 40 months (range, 12 to 103 mo). Radiographic union and clinical outcomes, including the ranges of wrist motion, grip strength, and the modified Mayo wrist score, were evaluated. Union was achieved in 18 of 21 wrists (86%) at a mean time of 14 weeks after surgery (range, 8 to 28 wk). Nonunions with proximal fragments less than 20% of the total scaphoid healed in 6 of 8 wrists. In a subset of these 8 wrists in which the proximal fragment was less than 15%, healing occurred in 2 of 4. The modified Mayo wrist score significantly improved from 46 to 78 points, and final wrist functions were rated as excellent in 5, good in 5, fair in 10, and poor in 1. Ranges of motion and grip strengths did not show significant changes after surgery. Vascularized distal radius bone grafting and K-wire fixation can heal scaphoid nonunions with small avascular proximal fragments, although motion and grip strength remain unchanged. Healing may be related to the size of the proximal pole fragment. Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  6. Platform technologies for decellularization, tunic-specific cell seeding, and in vitro conditioning of extended length, small diameter vascular grafts.

    Science.gov (United States)

    Fercana, George; Bowser, Devon; Portilla, Margarita; Langan, Eugene M; Carsten, Christopher G; Cull, David L; Sierad, Leslie N; Simionescu, Dan T

    2014-12-01

    The aim of this study was to generate extended length, small diameter vascular scaffolds that could serve as potential grafts for treatment of acute ischemia. Biological tissues are considered excellent scaffolds, which exhibit adequate biological, mechanical, and handling properties; however, they tend to degenerate, dilate, and calcify after implantation. We hypothesized that chemically stabilized acellular arteries would be ideal scaffolds for development of vascular grafts for peripheral surgery applications. Based on promising historical data from our laboratory and others, we chose to decellularize bovine mammary and femoral arteries and test them as scaffolds for vascular grafting. Decellularization of such long structures required development of a novel "bioprocessing" system and a sequence of detergents and enzymes that generated completely acellular, galactose-(α1,3)-galactose (α-Gal) xenoantigen-free scaffolds with preserved collagen, elastin, and basement membrane components. Acellular arteries exhibited excellent mechanical properties, including burst pressure, suture holding strength, and elastic recoil. To reduce elastin degeneration, we treated the scaffolds with penta-galloyl glucose and then revitalized them in vitro using a tunic-specific cell approach. A novel atraumatic endothelialization protocol using an external stent was also developed for the long grafts and cell-seeded constructs were conditioned in a flow bioreactor. Both decellularization and revitalization are feasible but cell retention in vitro continues to pose challenges. These studies support further efforts toward clinical use of small diameter acellular arteries as vascular grafts.

  7. 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.

  8. 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.

  9. Identification of risk factors for vascular thrombosis may reduce early renal graft loss - a review of recent literature

    DEFF Research Database (Denmark)

    Keller, Anna Krarup; Jørgensen, Troels Munch; Jespersen, Bente

    2012-01-01

    Renal graft survival has improved over the past years, mainly owing to better immunosuppression. Vascular thrombosis, though rare, therefore accounts for up to one third of early graft loss. We assess current literature on transplantation, identify thrombosis risk factors, and discuss means...... of avoiding thrombotic events and saving thrombosed grafts. The incidence of arterial thrombosis was reported to 0.2-7.5% and venous thrombosis 0.1-8.2%, with the highest incidence among children and infants, and the lowest in living donor reports. The most significant risk factors for developing thrombosis...

  10. In vivo bioimaging analysis of stromal vascular fraction-assisted fat grafting: the interaction and mutualism of cells and grafted fat.

    Science.gov (United States)

    Zhou, Shuang-Bai; Chiang, Cheng-An; Xie, Yun; Li, Hua; Liu, Kai; Kobayashi, Eiji; Li, Qing-Feng

    2014-11-27

    Unpredictable survival rate of transplanted fat is an obstacle in application of fat grafting. Although recent researches have suggested that adipose-derived stromal vascular fraction (SVF) could promote grafted fat survival, there has been seldom reports on tracing the dynamic change of grafted fat in vivo and on discussing interaction between transplanted SVFs and surrounding fat graft. Fat tissue and SVF separated from luciferase (Luc)-transgenic rats were applied for bioimaging analysis. The Luc-fat (0.2 mL) was subcutaneously injected into the back of nude mice with or without SVFs from 0.2 mL wild type rat fat, with bioimaging at 63 days. Immunohistochemical staining was performed to evaluate the structural integrity. Moreover, to evaluate the influence of surrounding fat tissue to transplanted SVFs, Luc-SVFs separated from 0.2 mL luciferase fat were transplanted to evaluate the influence of surrounding fat tissue to transplanted SVFs. The bioimaging results showed that fat tissues transplanted with SVFs had higher survival ratio than those transplanted without SVFs (49.99(5.38)% vs. 32.78(3.32)%; P fat grafts had more integral structure and less necrosis cysts. The results showed that, with the existence of grafted fat, transplanted SVF survived for a significantly longer time and could contribute to fat graft survival and regeneration by differentiating into structural cells. The results showed that SVF-assisted fat graft had significantly higher survival rate than that transplanted alone. Moreover, our research demonstrated that interaction between grafted fat and SVFs was important in SVF's long-term living and differentiation.

  11. Better primary stability with porous titanium particles than with bone particles in cemented impaction grafting: An in vitro study in synthetic acetabula

    NARCIS (Netherlands)

    Walschot, L.H.B.; Aquarius, R.; Schreurs, B.W.; Buma, P.; Verdonschot, Nicolaas Jacobus Joseph

    2013-01-01

    Aims Impaction bone grafting creates new bone stock after hip joint replacement. Utilizing a synthetic bone substitute instead of bone might increase primary stability and is not associated with graft shortage and pathogen transmission. This study compares the initial stability of a graft layer of

  12. Applying elastic fibre biology in vascular tissue engineering

    OpenAIRE

    Kielty, Cay M; Stephan, Simon; Sherratt, Michael J; Williamson, Matthew; Shuttleworth, C. Adrian

    2007-01-01

    For the treatment of vascular disease, the major cause of death in Western society, there is an urgent need for tissue-engineered, biocompatible, small calibre artery substitutes that restore biological function. Vascular tissue engineering of such grafts involves the development of compliant synthetic or biomaterial scaffolds that incorporate vascular cells and extracellular matrix. Elastic fibres are major structural elements of arterial walls that can enhance vascular graft design and pate...

  13. Sensing vascularization of ex-vivo produced oral mucosal equivalent (EVPOME) skin grafts in nude mice using optical spectroscopy

    Science.gov (United States)

    Vishwanath, Karthik; Gurjar, Rajan; Kuo, Shiuhyang; Fasi, Anthony; Kim, Roderick; Riccardi, Suzannah; Feinberg, Stephen E.; Wolf, David E.

    2014-03-01

    Repair of soft tissue defects of the lips as seen in complex maxillofacial injuries, requires pre-vascularized multi-tissue composite grafts. Protocols for fabrication of human ex-vivo produced oral mucosal equivalents (EVPOME) composed of epithelial cells and a dermal equivalent are available to create prelaminated flaps for grafting in patients. However, invivo assessment of neovascularization of the buried prelaminated flaps remains clinically challenging. Here, we use diffuse reflectance spectroscopy (DRS) and diffuse correlation spectroscopy (DCS) to non-invasively quantify longitudinal changes in the vessel density and blood-flow within EVPOME grafts implanted in the backs of SCID mice and subsequently to determine the utility of these optical techniques for assessing vascularization of implanted grafts. 20 animals were implanted with EVPOME grafts (1x1x0.05 cm3) in their backs. DRS and DCS measurements were obtained from each animal both atop the graft site and far away from the graft site, at one week post-implantation, each week, for four consecutive weeks. DRS spectra were analyzed using an inverse Monte Carlo model to extract tissue absorption and scattering coefficients, which were then used to extract blood flow information by fitting the experimental DCS traces. There were clear differences in the mean optical parameters (averaged across all mice) at the graft site vs. the off-site measurements. Both the total hemoglobin concentration (from DRS) and the relative blood flow (from DCS) peaked at week 3 at the graft site and declined to the off-site values by week 4. The optical parameters remained relatively constant throughout 4 weeks for the off-site measurements.

  14. A Capsular-based Vascularized Distal Radius Graft in Treatment of Proximal Pole Scaphoid Pseudoarthrosis. Case Study.

    Science.gov (United States)

    Sroga, Wojciech; Perez Giner, Rosa Ana

    2016-11-30

    We present a possible option for surgical treatment of proximal pole scaphoid pseudarthrosis. We used a vascularized distal radius bone graft that was pedicled on the dorsal capsule of the wrist joint. The publication consists of a case study, conclusions, indications and contraindications for the surgery.

  15. Immobilization of a bone and cartilage stimulating peptide to a synthetic bone graft.

    Science.gov (United States)

    Wang, Vivian; Misra, Gauri; Amsden, Brian

    2008-05-01

    A synthetic peptide fragment of human collagen type I (BCSP-1) was linked to the surface of a commercially available ceramic in an effort to improve the properties of the bone graft substitute to accelerate local healing. BCSP-1 was covalently immobilized on the surface of the ceramic via the linkers 3-aminopropyl-triethoxysilane (APTES) and suberic acid bis-N-hydroxysuccinimide ester (DSS). The chosen chemistry was non-cytotoxic. A rat calvaria cell assay using alkaline phosphatase (ALP) as an osteoblast differentiation marker, showed that modifying the surface of the ceramic was enough to enhance ALP activity, although the total cell population on the surface decreased. A significant increase in ALP activity/cell was noted with serum albumin bound to the surface, however, the BCSP-1 bound surface exhibited an even greater ALP activity that showed a surface concentration dependent trend. An optimal BCSP-1 surface density in the range of 0.87-2.24 nmol/cm2 elicited the maximum ALP activity/cell at day 6 of culture. The peptide bound ceramic generated an ALP activity/cell that was roughly 3-fold higher than the non-modified ceramic and 2-fold higher than the APTES-grafted ceramic.

  16. Do stress fractures induce hypertrophy of the grafted fibula? A report of three cases received free vascularized fibular graft treatment for tibial defects.

    Science.gov (United States)

    Qi, Yong; Sun, Hong-Tao; Fan, Yue-Guang; Li, Fei-Meng; Lin, Zhou-Sheng

    2016-06-01

    The presence of large segmental defects of the diaphyseal bone is challenging for orthopedic surgeons. Free vascularized fibular grafting (FVFG) is considered to be a reliable reconstructive procedure. Stress fractures are a common complication following this surgery, and hypertrophy is the main physiological change of the grafted fibula. The exact mechanism of hypertrophy is not completely known. To the best of our knowledge, no studies have examined the possible relationship between stress fractures and hypertrophy. We herein report three cases of patients underwent FVFG. Two of them developed stress fractures and significant hypertrophy, while the remaining patient developed neither stress fractures nor significant hypertrophy. This phenomenon indicates that a relationship may exist between stress fractures and hypertrophy of the grafted fibula, specifically, that the presence of a stress fracture may initiate the process of hypertrophy.

  17. Utility of Covered Stents for Revision of Aging Failing Synthetic Hemodialysis Grafts: A Report of Three Cases

    International Nuclear Information System (INIS)

    Silas, Anne M.; Bettmann, Michael A.

    2003-01-01

    Three aging failing hemodialysis polytetrafluoroethylene bypass shunts, average age 44 months, previously percutaneously revised with balloon angioplasty, presented with pseudoaneurysms and recurrent thrombosis. All were treated with percutaneous covered stent placement within their affected limbs. One graft was ligated 1 month after treatment for infected overlying skin ulcer, though this graft was subsequently surgically revised with interposition graft and the covered stent portion remains functional at 19 month follow-up. The 18- and 13- month follow- up of the remaining 2 patients shows that the covered stents remained patent and they are functional and being successfully and routinely punctured for dialysis. In this elderly population, the use of covered stents may prolong the functional life of failing hemodialysis bypass grafts, reducing the number of percutaneous and surgical interventions and further sparing other vascular access sites

  18. Rare complication of a sigmoid colon perforation after a kidney transplant with an artificial vascular graft.

    Science.gov (United States)

    Inoue, Shogo; Shiina, Hiroaki; Arichi, Naoko; Mitusi, Yozo; Hiraoka, Takeo; Wake, Koji; Sumura, Masahiro; Honda, Satoshi; Urakami, Shinji; Igawa, Mikio

    2011-06-01

    A 65-year-old man (blood type O) came to our hospital for transplant of an unrelated kidney (6/6 mismatch of HLA genotype) donated by his living 60-year-old wife (blood type B). The planned right donor nephrectomy was uneventful, with a warm ischemic time of 5 minutes, but her right renal vein was too fragile and weak to be repaired for vascular anastomosis. Therefore, we used an artificial vascular graft (polytetrafluoroethylene) interposed between the donor renal vein and the recipient's left external iliac vein. On the 11th day after surgery, infraphrenic free air (identified by a chest radiograph) made us do an emergent laparoscopic examination that showed a perforation of his sigmoid colon. A transient transverse colostomy was therefore prepared. The transient transverse colostomy was closed 8 months after the kidney transplant. Twelve months after the transplant, the patient is doing well with a serum creatinine level of 150.44 micromol/L (1.7 mg/dL).

  19. Combining electrospinning and fused deposition modeling for the fabrication of a hybrid vascular graft

    International Nuclear Information System (INIS)

    Centola, M; Rainer, A; Trombetta, M; Spadaccio, C; Genovese, J A; De Porcellinis, S

    2010-01-01

    Tissue engineering of blood vessels is a promising strategy in regenerative medicine with a broad spectrum of potential applications. However, many hurdles for tissue-engineered vascular grafts, such as poor mechanical properties, thrombogenicity and cell over-growth inside the construct, need to be overcome prior to the clinical application. To surmount these shortcomings, we developed a poly-l-lactide (PLLA)/poly-ε-caprolactone (PCL) scaffold releasing heparin by a combination of electrospinning and fused deposition modeling technique. PLLA/heparin scaffolds were produced by electrospinning in tubular shape and then fused deposition modeling was used to armor the tube with a single coil of PCL on the outer layer to improve mechanical properties. Scaffolds were then seeded with human mesenchymal stem cells (hMSCs) and assayed in terms of morphology, mechanical tensile strength, cell viability and differentiation. This particular scaffold design allowed the generation of both a drug delivery system amenable to surmount thrombogenic issues and a microenvironment able to induce endothelial differentiation. At the same time, the PCL external coiling improved mechanical resistance of the microfibrous scaffold. By the combination of two notable techniques in biofabrication-electrospinning and FDM-and exploiting the biological effects of heparin, we developed an ad hoc differentiating device for hMSCs seeding, able to induce differentiation into vascular endothelium.

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

    Directory of Open Access Journals (Sweden)

    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.

  1. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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

  5. Evaluation of a xenogeneic acellular collagen matrix as a small-diameter vascular graft in dogs--preliminary observations.

    Science.gov (United States)

    Nemcova, S; Noel, A A; Jost, C J; Gloviczki, P; Miller, V M; Brockbank, K G

    2001-01-01

    Autogenous veins are the materials of choice for arterial reconstruction. In the absence of autogenous material, prosthetic materials are used. However, vascular prostheses of less than 0.4 cm in diameter have low long-term patency. This study was designed to determine if cells would infiltrate an engineered xenogeneic biomaterial used as a small diameter arterial graft in dogs and, if so, to determine the phenotype of the infiltrating cells. Nine acellular xenogeneic grafts (0.4 cm in diameter, 5 cm long), composed of porcine collagen derived from the submucosa of the small intestine and type I bovine collagen, were implanted as end to-end interposition grafts in femoral arteries of five male mongrel dogs (total of nine grafts). All dogs received daily aspirin (325 mg). Patency of implanted grafts was monitored weekly by Duplex ultrasonography. After 9 weeks, or earlier in case of blood flow reduction by at least 75%, grafts were explanted and prepared for light or electron microscopy to evaluate cellularization. Eight of nine grafts remained patent up to 9 weeks. At explant, diameters were 0.31 +/- 0.02 cm at the midgraft, and 0.14 +/- 0.01 and 0.19 +/- 0.01 cm at the proximal and distal anastomoses. At explant, cells of mesenchymal origin (endothelial cells, smooth muscle cells, myofibroblasts) were embedded in the extracellular matrix of the graft scaffold. Minimal evidence of cellular inflammatory reaction and no aneurysmal dilatation or thrombus formation was detected. Variable degrees of hyperplasia were present at proximal and distal anastomoses. This preliminary study demonstrates that a collagen-based xenogeneic biomaterial provides a scaffold for cellularization when used for arterial reconstruction in dogs.

  6. Effects of neurolytic concentrations of alcohol and phenol on Dacron and Gore-Tex vascular prosthetic grafts.

    Science.gov (United States)

    Gale, D W; Valley, M A; Rogers, J N; Poterack, K A

    1994-01-01

    Neurolytic nerve block, using either alcohol (A) or phenol (P), is frequently used to treat intractable pain. However, these agents may disrupt the integrity of prosthetic vascular grafts. To investigate this possibility, the tensile strength of Dacron (Meadox Medicals, Oakland, NJ) and Gore-Tex (W.L. Gore Associates, Flagstaff, AZ) vascular grafts was determined after in vitro exposure to various clinically used concentrations of A or P. Segments of Dacron and Gore-Tex graft were placed in the following solutions: saline (S), 6% and 9% P, and 25%, 50%, 75%, and 100% A, and stored at 23 degrees +/- 1 degree C for 72 hours. Axial maximum load (in kilonewtons, KN) and strain (in mm/mm) were determined with an Instron universal testing machine (Instron Corporation, Camden, MA). Samples from the S, 9% P, and the 100% A groups were evaluated using a scanning electron microscope. Dacron tensile strength decreased a maximum of 23% after exposure to 50%, 75%, and 100% A. Dacron strain capacity decreased after exposure to A (50%, 75%, 100%) and P (6%, 9%). Scanning electron microscope of both P and A showed significant degradation. No changes were found in the Gore-Tex group after exposure to P or A, however, scanning electron microscope of the 100% A sample showed moderate fiber degradation. The study shows that Dacron woven grafts are degraded by concentrations of A of at least 50%, and to a lesser extent, concentrations of at least 6%, while Gore-Tex had only minimal changes. While neurolytic block offers distinct advantages in patients with terminal cancer pain, the findings suggest that the use of more conservative modalities, such as oral medication regimens, be considered for the treatment of intractable pain in patients with vascular prosthetic grafts that are proximate to the proposed site of neurolysis.

  7. 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.

  8. Fluorescence-based retention assays reveals sustained release of vascular endothelial growth factor from bone grafts.

    Science.gov (United States)

    Kang, Wonmo; Yun, Ye-Rang; Lee, Dong-Sung; Kim, Tae-Hyun; Kim, Joong-Hyun; Kim, Hae-Won; Jang, Jun-Hyeog

    2016-01-01

    The sustained release of growth factors following their implantation in vivo is essential for successful outcomes in bone tissue engineering. In this study, we evaluated the release kinetics and delivery efficacies of vascular endothelial growth factor (VEGF), a potent angiogenic growth factor, incorporated into calcium phosphate bone grafts (BGs). We evaluated the release profile of VEGF from BGs using a novel fluorescence-based retention assay, which revealed that VEGF loaded on BGs can be released in a sustained manner without an initial burst (near zero-order cumulative release) with a controlled release rate of 13.6% per week for up to 7 weeks. In contrast, an ELISA-based release assay showed VEGF to have an early burst-release profile for the first week. However, the biological activity of VEGF released from the BGs was preserved over the 7-week release period, which is consistent with the sustained-release profile observed in the fluorescence-based retention assay. Furthermore, the in vivo bone-forming action of the VEGF-loaded BGs was well demonstrated in a rat subcutaneous model. Taken together, the sustained release of VEGF loaded onto BGs was effective in stimulating proliferation, angiogenesis and osteogenesis, suggesting the ultimate value of VEGF-engineered BGs for bone tissue engineering. © 2015 Wiley Periodicals, Inc.

  9. 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

  10. Efficacy of collagen silver-coated polyester and rifampin-soaked vascular grafts to resist infection from MRSA and Escherichia coli in a dog model.

    Science.gov (United States)

    Schneider, Fabrice; O'Connor, Stephen; Becquemin, Jean Pierre

    2008-11-01

    The primary objective of this study was to compare the efficacy of a collagen silver-coated polyester graft, InterGard, with a gelatin-sealed graft, Gelsoft, both soaked in rifampin, for resistance to direct bacterial contamination in an animal model. The second objective was to confirm the lack of inflammation from silver acetate. Vascular grafts, 6 mm in diameter, were implanted in the infrarenal aorta of 28 dogs. Intravenous cefamandole (20 mg/kg) was injected intraoperatively in all dogs. The dogs were divided into three groups. Group I included 12 dogs. Six dogs received silver grafts and six dogs received gelatin-sealed grafts, all soaked with rifampin. Grafts implanted in group I were directly infected with methicillin-resistant Staphylococcus aureus (MRSA). Group II included also six silver grafts and six gelatin-sealed grafts, all soaked with rifampin. Dogs of group II were directly infected with Escherichia coli. Group III comprised four dogs, which received gelatin unsealed grafts, directly infected with MRSA, the control group. All dogs were followed by regular clinical examination, including blood cultures. Grafts in groups I and III and in group II were harvested at 30 days and 10 days, respectively. Bacterial analyses were performed on the explanted grafts. Histology was performed on both the tissue samples and the anastomotic sites of the harvested grafts. In group I, no grafts were infected with MRSA, irrespective of graft type. In group II, no silver grafts were infected with E. coli, whereas one (16.6%) of six gelatin-sealed grafts was infected (p = 0.317). In group III, three (75%) of the four grafts were infected with MRSA. The infection rate in the silver grafts and the gelatin-sealed grafts soaked in rifampin in group I compared with the unsealed gelatin grafts in group III was statistically significantly different (p anastomoses in three (25%) gelsoft grafts of 12 in groups I and II. There were no clinical or biological signs of inflammation

  11. Laparoscopic diagnosis and treatment of aortic vascular prosthetic graft infections in a porcine model

    DEFF Research Database (Denmark)

    Gao, Hongding; Lund, L; Prag, J

    2008-01-01

    To study the feasibility and efficacy of experimental laparoscopy in the diagnosis of aortic graft infection in pigs.......To study the feasibility and efficacy of experimental laparoscopy in the diagnosis of aortic graft infection in pigs....

  12. The improved biological response of shark tooth bioapatites in a comparative in vitro study with synthetic and bovine bone grafts.

    Science.gov (United States)

    López-Álvarez, M; Pérez-Davila, S; Rodríguez-Valencia, C; González, P; Serra, J

    2016-06-07

    Autologous bone is considered to be the gold standard for bone tissue regeneration, providing more highly efficient functional responses compared to synthetic materials, and avoiding the rejection risks of allogenic grafts. However, it presents limitations for certain types of surgery due to its high resorption levels and donor site morbidity. Different biphasic synthetic composites, based onnon-apatitic calcium phosphates enriched with apatitic phases-such as hydroxyapatite, and bioderived bone grafts of bovine and porcine origin-are proposed as lower resorption materials due to their higher crystalline structure. The present work proposes two new sources of bioapatites for bone filler applications obtained from the dentine and enameloid of shark teeth, respectively. These bioapatites each present a characteristic apatite-based composition and additional enrichments of specific trace elements, such as magnesium and fluorine, with proven roles in bone metabolism. Their processing and physicochemical characterization (SEM, FT-Raman and XRD) is presented, together with an in vitro evaluation of osteogenic activity compared to a commercial bovine mineralized matrix and synthetic HA/β TCP grafts. The results proved the globular morphology (0.5-1.5 μm) and porosity (~50 μm and ~0.5-1 μm) of shark dentine bioapatites with biphasic composition: apatitic (hydroxyapatite and apatite-(CaF)), non-apatitic (whitlockite), and an apatitic phase (fluorapatite), organized in oriented crystals in enameloid bioapatites. An evaluation of the pre-osteoblast MC3T3-E1 morphology revealed the colonization of pores in dentine bioapatites and an aligned cell growth in the oriented enameloid crystals. A higher proliferation (p  aligned fluorapatite crystals of enameloid bioapatites in promoting greater osteogenic activity was confirmed with a significantly increased ALP synthesis (p  <  0.01) compared to the commercial grafts.

  13. Efficacy and safety of negative pressure wound therapy for Szilagyi grade III peripheral vascular graft infection.

    Science.gov (United States)

    Cheng, Hsu-Tang; Hsu, Yung-Chang; Wu, Chao-I

    2014-12-01

    A best evidence topic in vascular surgery was written according to a structured protocol. The question addressed was whether it is safe and effective to use negative pressure wound therapy (NPWT) for Szilagyi grade III (i.e. the arterial implant proper involved in the infection) peripheral vascular graft infection. Altogether, 69 papers were found using the reported search. From the search results, reference lists of potentially eligible studies and related citations in PubMed, seven papers represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. In the only randomized, controlled trial that compared NPWT (n = 10) and alginate dressing change (n = 10), the NPWT group demonstrated shorter time to full skin epithelialization (median 57 vs 104 days; P = 0.026). In the other six case series, the recruited case number ranged from 12 to 72. The mode of NPWT varied among the included studies, with the majority using a continuous negative pressure of 125 mmHg. One study combined NPWT and sartorius myoplasty, another used sartorius myoplasty in selected cases and others did not. The mean duration of using NPWT ranged from 14.2 to 43 days. The mean duration to achieve complete wound healing ranged from 24 (the study with sartorius myoplasty) to 51 days. The NPWT treatment failure rate ranged from 0 (the study with sartorius myoplasty) to 25%. The major complication of NPWT was bleeding and the incidence rate was reported to be 1 year of follow-up) showed that NPWT with a continuous negative pressure of 125 mmHg, or combined NPWT and sartorius myoplasty, may shorten the time to complete wound healing by 2 months, have a >70% success rate, and have a <10% NPWT-related complication rate. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights

  14. Breast Reconstruction with Enhanced Stromal Vascular Fraction Fat Grafting: What Is the Best Method?

    Science.gov (United States)

    Gentile, Pietro; Scioli, Maria Giovanna; Orlandi, Augusto; Cervelli, Valerio

    2015-06-01

    Actually, there are 2 main methods to obtain stromal vascular fraction (SVF): enzymatic digestion and mechanical filtration; however, the available systems report heterogeneous and sometimes not univocal results. The aim of this study is to evaluate different procedures for SVF isolation and compare their clinical efficacy in the treatment of soft-tissue defects in plastic and reconstructive surgery. The authors evaluated Celution and Medikhan, enzymatic systems, and Fatstem and Mystem system, mechanical separation systems. Fifty patients affected by breast soft-tissue defects were treated in the Plastic and Reconstructive Surgery Department of Tor Vergata University of Rome. Four groups of 10 patients were managed with enhanced SVF fat grafts using cells obtained by Celution (Cytori Therapeutics, Inc., San Diego, Calif.), Medikhan (Medi-Khan Inc., West Hollywood, Calif.), Fatstem (Fatstem CORIOS Soc. Coop, San Giuliano Milanese, Italy), and Mystem (Mystem evo Bi-Medica, Treviolo, Italy) systems. A control group of 10 patients was treated with only centrifuged fat according to Coleman's technique. In enhanced SVF-treated patients treated with cells obtained by Celution system, we observed a 63% ± 6.2% maintenance of contour restoring after 1 year, compared with 39% ± 4.4% of control group. In patients treated with SVF obtained by Medikhan system, we observed a 39% ± 3.5% maintenance, whereas enhanced SVF with Fatstem and Mystem systems gave a 52% ± 4.6% and 43% ± 3.8% maintenance of contour restoring, respectively. SVF cell counting indicated that Celution and Fatstem were the most efficient systems to obtain SVF cells. Celution and Fatstem were the 2 best automatic systems to obtain SVF and to improve maintenance of fat volume and prevent the reabsorption.

  15. Bilateral vascularized rib grafts to promote spinopelvic fixation in patients with sacral agenesis and spinopelvic dissociation: a new surgical technique.

    Science.gov (United States)

    Ferland, Catherine E; Sardar, Zeeshan M; Abduljabbar, Fahad; Arlet, Vincent; Ouellet, Jean A

    2015-12-01

    Sacral agenesis is a rare congenital disorder that may have spinopelvic instability due to sacroiliac joint malformation. Surgical indication in patients with sacral agenesis is to improve their sitting balance and protect the visceral organs. Achieving solid arthrodesis across this congenital malformation is challenging and prone to non-union. The purpose of this study was to describe a novel surgical technique with vascularized ribs for management of sacral agenesis and complex spinopelvic dissociation. Retrospective study. Six patients with sacral agenesis were reviewed and followed for a mean of 8.5 years after spinopelvic fusion augmented with vascularized rib graft spanning the lumbo-pelvic junction. The primary outcome measure was the presence or absence of a stable spinopelvic junction and fusion across the spine-vascular rib grafts-pelvis interface. The secondary outcome measures were maintenance of pelvic obliquity, lumbosacral kyphosis, and overall sagittal balance. The surgical procedure consisted of two-stage surgeries performed 6-12 weeks apart. The first stage consisted of spinal instrumentation and correction of the deformity via a posterior approach and impaction of one of the vascularized ribs from the spine to the iliac crest. The second stage consisted of an anterior thoraco-lumbar approach for spinal fusion and the second vascularized rib spanning the spine to the iliac crest. All six patients eventually achieved a solid spinal and spinopelvic fusion. All vascularized ribs increased in diameter over time. A high complication rate consisted mainly of spinal infections and prominent hardware requiring revision surgeries (a total of seven procedures in four patients). Two patients had decreased mobility secondary to spinopelvic surgery at last follow-up. Spinopelvic fusion can be successfully achieved with this novel surgical technique using vascularized rib grafts. This technique allows for biological long-term maintenance of the sagittal

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

    Science.gov (United States)

    Beutel, Bryan G; 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 60s. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. 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.

  18. 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

  19. 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

  20. Alveolar Ridge Preservation Using a Novel Synthetic Grafting Material: A Case with Two-Year Follow-Up

    Directory of Open Access Journals (Sweden)

    Peter Fairbairn

    2018-01-01

    Full Text Available This case report highlights the use of a novel in situ hardening synthetic (alloplastic, resorbable, bone grafting material composed of beta tricalcium phosphate and calcium sulfate, for alveolar ridge preservation. A 35-year-old female patient was referred by her general dentist for extraction of the mandibular right first molar and rehabilitation of the site with a dental implant. The nonrestorable tooth was “atraumatically” extracted without raising a flap, and the socket was immediately grafted with the synthetic biomaterial and covered with a hemostatic fleece. No membrane was used, and the site was left uncovered without obtaining primary closure, in order to heal by secondary intention. After 12 weeks, the architecture of the ridge was preserved, and clinical observation revealed excellent soft tissue healing without loss of attached gingiva. At reentry for placement of the implant, a bone core biopsy was obtained, and primary implant stability was measured by final seating torque and resonance frequency analysis. Histological analysis revealed pronounced bone regeneration while high levels of primary implant stability were recorded. The implant was successfully loaded 12 weeks after placement. Clinical and radiological follow-up examination at two years revealed stable and successful results regarding biological, functional, and esthetic parameters.

  1. Alveolar Ridge Preservation Using a Novel Synthetic Grafting Material: A Case with Two-Year Follow-Up.

    Science.gov (United States)

    Fairbairn, Peter; Leventis, Minas; Mangham, Chas; Horowitz, Robert

    2018-01-01

    This case report highlights the use of a novel in situ hardening synthetic (alloplastic), resorbable, bone grafting material composed of beta tricalcium phosphate and calcium sulfate, for alveolar ridge preservation. A 35-year-old female patient was referred by her general dentist for extraction of the mandibular right first molar and rehabilitation of the site with a dental implant. The nonrestorable tooth was "atraumatically" extracted without raising a flap, and the socket was immediately grafted with the synthetic biomaterial and covered with a hemostatic fleece. No membrane was used, and the site was left uncovered without obtaining primary closure, in order to heal by secondary intention. After 12 weeks, the architecture of the ridge was preserved, and clinical observation revealed excellent soft tissue healing without loss of attached gingiva. At reentry for placement of the implant, a bone core biopsy was obtained, and primary implant stability was measured by final seating torque and resonance frequency analysis. Histological analysis revealed pronounced bone regeneration while high levels of primary implant stability were recorded. The implant was successfully loaded 12 weeks after placement. Clinical and radiological follow-up examination at two years revealed stable and successful results regarding biological, functional, and esthetic parameters.

  2. Management of scaphoid nonunions with vascularized bone grafts from the distal radius: mid- to long-term follow-up.

    Science.gov (United States)

    Malizos, Konstantinos N; Dailiana, Zoe; Varitimidis, Sokratis; Koutalos, Antonios

    2017-01-01

    Scaphoid nonunion represents a challenging problem that leads to disability if neglected. Vascularized bone grafts are proposed to augment the local biology and increase the likelihood of union but long-term outcomes are sparse. In this work, we present the mid- to long-term outcome of 140 scaphoid nonunions managed with vascularized bone grafts from the distal radius. Sixteen patients underwent concomitant closed wedge osteotomy of the distal radius because of arthritic changes. There were 130 males and ten females, with mean time from injury to surgery 3.3 years. Delayed presentation was associated with arthritic changes. Forty-two patients had avascular necrosis of the proximal pole and sixteen had more severe arthritic changes. The mean follow-up was 10 years. Pain decreased postoperatively but range of motion did not improve but only in early reconstructions. Grip strength reached 79% of the non-injured hand. Mayo modified wrist score improved from 56 to 84 (p radius reliably led to highest rate of bone healing with good mid- to long-term outcomes. Enhancement of the local biology and reconstitution of scaphoid and carpal height resulted in improved function mostly in early interventions.

  3. Restoration of the Active Forearm Rotation Using Vascularized Free Fibular Graft and Radial Head Arthroplasty for a Wide Defect of the Proximal Radius.

    Science.gov (United States)

    Sato, Ryosuke; Hamada, Yoshitaka; Hibino, Naohito; Nishisho, Toshihiko; Tonogai, Ichiro; Endo, Kenji; Sairyo, Koichi

    2017-12-01

    In this report we present a case of re-stabilization of the proximal radius using vascularized free fibular graft combined with anconeus arthroplasty to stabilize the transplanted fibula in a patient with large loss of the proximal radius due to Ewing's sarcoma. A 20-year-old woman had Ewing's sarcoma in the proximal three-fourths of the radius. The resection of large part of the radius containing radial head were necessary for removal of the sarcoma. Reconstruction of the proximal radius was performed using vascularized free fibular graft and the transplanted fibula was stabilized by attaching the anconeus to the proximal edge of the fibula. 2 years after surgery, she had neither recurrence nor metastasis, and achieved functional recovery. The combination anconeus arthroplasty with vascularized free fibular graft can be a good technique for re-stabilization of the elbow and recovery of the forearm function.

  4. 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

  5. Simultaneous Iliac Vein Bovine Pericardial Patch Venoplasty and Creation of PTFE Lower Limb Arteriovenous Fistula Graft for Rescue Vascular Access.

    Science.gov (United States)

    Meecham, Lewis; Fisher, Owain; Kirby, George; Evans, Richard; Buxton, Pauline; Legge, Jocelyn; Rajagopalan, Sriram; Asquith, John; Pherwani, Arun

    2016-10-01

    We present a case of external iliac vein patch venoplasty to accommodate rescue vascular access via a polytetrafluoroethylene loop arteriovenous fistula graft (AVG) for a patient with multiple central venous stenoses. A 35-year-old female with anti-glomerular basement membrane antibody disease required rescue vascular access for hemodialysis. Repeated occlusion and/or thrombosis of long-term central venous access cannulae, to facilitate dialysis, had caused stenosis of brachiocephalic veins: right external iliac vein and occlusion of the left common iliac vein. A previous right brachiobasilic fistula had occluded within 1 year. No other upper limb options for arteriovenous fistula (AVF) were available. A right external iliac vein bovine patch angioplasty concurrently with a polytetrafluoroethylene AV graft between common femoral artery and common femoral vein was performed to restore venous patency and allow rescue dialysis access. At 3-year follow-up, the fistula remains widely patent with 2 L/min flow rates and no recurrent stenosis to the treated iliac vein. She has not required any further surgical or interventional radiological procedures to maintain fistula or central venous patency. Central venous stenosis or occlusion is common for patients requiring dialysis, especially those with multiple previous long-term central venous cannulations. If restriction of outflow is present, AVF may fail. Venous patch angioplasty in these cases is a successful technique, allowing AVF formation and long-term patency. Central venous stenosis can be treated successfully with patch venoplasty to accommodate AVF/AVG formation for rescue vascular access; this is a potentially lifesaving intervention for patients requiring dialysis. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Value of a skin island flap as a postoperative predictor of vascularized fibula graft viability in extensive diaphyseal bone defect reconstruction.

    Science.gov (United States)

    Guo, Q-F; Xu, Z-H; Wen, S-F; Liu, Q-H; Liu, S-H; Wang, J-W; Li, X-Y; Xu, H-H

    2012-09-01

    To evaluate the feasibility and reliability of free vascularized fibular graft with skin island flap for reconstruction of large diaphyseal bone defect. The clinical results of vascularized fibular graft and experiences related to the importance and reliability of a monitoring island flap for the reconstruction of various long-bone defects were reviewed in 87 patients. Bony reconstruction was achieved in 82 of the 87 patients. Arterial thrombosis of anastomosed vessel in two patients and venous congestion of monitoring flap in nine patients occurred in the early postoperative periods. All of them were managed by immediate thrombectomy and reanastomosis, alternatively the thrombotic veins were replaced by new veins to anastomose with the superficial veins in five patients. Partial flap necrosis was noted in six patients, but additional surgical intervention was not required. The vascularized fibula survived and bony fusion was achieved in all patients. Postoperative stress fractures of the fibula graft occurred in 19 (21.8%) patients (once in seven patients, twice in five patients, three or more times in seven) as the mechanical stress to the graft increased. Included fracture on the tibia in 12 patients, humerus in one and femur in six. Treatments included casting in 11 patients, percutaneous pinning in one case, and adjustment of external fixator in seven patients. Bony union was finally achieved an average of 9.6 months after fracture. Correct alignment between the recipient bone and the external fixator is a prerequisite to preventing graft fracture. Vascularized fibula transfer is a valuable procedure for long-bone defects, and a skin island-monitoring flap is a simple, extremely useful, and reliable method for assessing the vascular status of vascularized fibula. Level IV. Retrospective study. Copyright © 2012. Published by Elsevier Masson SAS.

  7. Wall shear stress and near-wall convective transport: Comparisons with vascular remodelling in a peripheral graft anastomosis

    Science.gov (United States)

    Gambaruto, A. M.; Doorly, D. J.; Yamaguchi, T.

    2010-08-01

    Fluid dynamic properties of blood flow are implicated in cardiovascular diseases. The interaction between the blood flow and the wall occurs through the direct transmission of forces, and through the dominating influence of the flow on convective transport processes. Controlled, in vitro testing in simple geometric configurations has provided much data on the cellular-level responses of the vascular walls to flow, but a complete, mechanistic explanation of the pathogenic process is lacking. In the interim, mapping the association between local haemodynamics and the vascular response is important to improve understanding of the disease process and may be of use for prognosis. Moreover, establishing the haemodynamic environment in the regions of disease provides data on flow conditions to guide investigations of cellular-level responses. This work describes techniques to facilitate comparison between the temporal alteration in the geometry of the vascular conduit, as determined by in vivo imaging, with local flow parameters. Procedures to reconstruct virtual models from images by means of a partition-of-unity implicit function formulation, and to align virtual models of follow-up scans to a common coordinate system, are outlined. A simple Taylor series expansion of the Lagrangian dynamics of the near-wall flow is shown to provide both a physical meaning to the directional components of the flow, as well as demonstrating the relation between near-wall convection in the wall normal direction and spatial gradients of the wall shear stress. A series of post-operative follow-up MRI scans of two patient cases with bypass grafts in the peripheral vasculature are presented. These are used to assess how local haemodynamic parameters relate to vascular remodelling at the location of the distal end-to-side anastomosis, i.e. where the graft rejoins the host artery. Results indicate that regions of both low wall shear stress and convective transport towards the wall tend to be

  8. Recipient gene polymorphisms in the Th-1 cytokines IL-2 and IFN-gamma in relation to acute rejection and graft vascular disease after clinical heart transplantation

    NARCIS (Netherlands)

    Holweg, C T J; Peeters, A M A; Balk, A H M M; Uitterlinden, A G; Niesters, H G M; Maat, A P W M; Weimar, W; Baan, C C

    2003-01-01

    IL-2 and IFN-gamma are associated with acute rejection (AR) and graft vascular disease (GVD) after clinical heart transplantation. Polymorphisms in the genes of IL-2 (T-330G in the promoter) and IFN-gamma (CA repeat in the first intron) influence the production levels of these cytokines. Therefore,

  9. Intragraft platelet-derived growth factor-alpha and transforming growth factor-beta1 during the development of accelerated graft vascular disease after clinical heart transplantation

    NARCIS (Netherlands)

    de Groot-Kruseman, H A; Baan, C C; Mol, W M; Niesters, H G; Maat, A P; Balk, A H; Weimar, W

    1999-01-01

    This study was to determine whether the growth factors platelet-derived growth factor-alpha (PDGF-alpha) and transforming growth factor-beta1 (TGF-beta1) contribute to the development of graft vascular disease (GVD) after clinical heart transplantation. We analysed intragraft PDGF-alpha and

  10. Use of rifampin-soaked gelatin-sealed polyester grafts for in situ treatment of primary aortic and vascular prosthetic infections.

    Science.gov (United States)

    Bandyk, D F; Novotney, M L; Johnson, B L; Back, M R; Roth, S R

    2001-01-01

    In situ treatment of artery/graft infection has distinct advantages compared to vessel excision and extra-anatomic bypass procedures. Based on animal studies of a rifampin-soaked, gelatin-impregnated polyester graft that demonstrated prolonged in vivo antibacterial activity, this antibiotic-bonded graft was used selectively in patients for in situ treatment of low-grade Gram-positive prosthetic graft infections or primary aortic infections not amenable to excision and ex situ bypass. In a 5-year period (1995-1999), 27 patients with prosthetic graft infection (aortofemoral, n = 18, femorofemoral, n = 3; axillofemoral, n = 1) or primary aortic infection (mycotic aneurysm, n = 3; infected AAA, n = 2) underwent excision of the infected vessel and in situ replacement with a rifampin soaked (45-60 mg/ml for 15 min) gelatin-impregnated polyester graft. All prosthetic graft infections were low grade in nature, caused Gram-positive bacteria (Staphylococcus epidermidis, 16; Staphylococcus aureus, 5; Streptococcus, 1), and were treated electively. Patients with mycotic aortic aneurysm presented with sepsis and underwent urgent or emergent surgery. Two (8%) patients died-1 as a result of a ruptured Salmonella mycotic aortic aneurysm and the other from methicillin-resistant S. aureus infection following deep vein replacement of an in situ replaced femorofemoral graft. No amputations or late deaths as the result of vascular infection occurred in the 25 surviving patients. Two patients developed recurrent infection caused by a rifampin-resistant S. epidermidis in a replaced aortofemoral graft limb and were successfully treated with graft excision and in situ autogenous vein replacement. Eighteen patients remain alive and clinically free of infection after a mean follow-up interval of 17 months. In situ replacement treatment using a rifampin-bonded prosthetic graft for low-grade staphylococcal arterial infection was safe, durable, and associated with eradication of clinical signs

  11. Gene expression analysis of skin grafts and cultured keratinocytes using synthetic RNA normalization reveals insights into differentiation and growth control.

    Science.gov (United States)

    Katayama, Shintaro; Skoog, Tiina; Jouhilahti, Eeva-Mari; Siitonen, H Annika; Nuutila, Kristo; Tervaniemi, Mari H; Vuola, Jyrki; Johnsson, Anna; Lönnerberg, Peter; Linnarsson, Sten; Elomaa, Outi; Kankuri, Esko; Kere, Juha

    2015-06-25

    Keratinocytes (KCs) are the most frequent cells in the epidermis, and they are often isolated and cultured in vitro to study the molecular biology of the skin. Cultured primary cells and various immortalized cells have been frequently used as skin models but their comparability to intact skin has been questioned. Moreover, when analyzing KC transcriptomes, fluctuation of polyA+ RNA content during the KCs' lifecycle has been omitted. We performed STRT RNA sequencing on 10 ng samples of total RNA from three different sample types: i) epidermal tissue (split-thickness skin grafts), ii) cultured primary KCs, and iii) HaCaT cell line. We observed significant variation in cellular polyA+ RNA content between tissue and cell culture samples of KCs. The use of synthetic RNAs and SAMstrt in normalization enabled comparison of gene expression levels in the highly heterogenous samples and facilitated discovery of differences between the tissue samples and cultured cells. The transcriptome analysis sensitively revealed genes involved in KC differentiation in skin grafts and cell cycle regulation related genes in cultured KCs and emphasized the fluctuation of transcription factors and non-coding RNAs associated to sample types. The epidermal keratinocytes derived from tissue and cell culture samples showed highly different polyA+ RNA contents. The use of SAMstrt and synthetic RNA based normalization allowed the comparison between tissue and cell culture samples and thus proved to be valuable tools for RNA-seq analysis with translational approach. Transciptomics revealed clear difference both between tissue and cell culture samples and between primary KCs and immortalized HaCaT cells.

  12. Linking gene dynamics to vascular hyperplasia - Toward a predictive model of vein graft adaptation.

    Directory of Open Access Journals (Sweden)

    Stefano Casarin

    Full Text Available Reductionist approaches, where individual pieces of a process are examined in isolation, have been the mainstay of biomedical research. While these methods are effective in highly compartmentalized systems, they fail to account for the inherent plasticity and non-linearity within the signaling structure. In the current manuscript, we present the computational architecture for tracking an acute perturbation in a biologic system through a multiscale model that links gene dynamics to cell kinetics, with the overall goal of predicting tissue adaptation. Given the complexity of the genome, the problem is made tractable by clustering temporal changes in gene expression into unique patterns. These cluster elements form the core of an integrated network that serves as the driving force for the response of the biologic system. This modeling approach is illustrated using the clinical scenario of vein bypass graft adaptation. Vein segments placed in the arterial circulation for treatment of advanced occlusive disease can develop an aggressive hyperplastic response that narrows the lumen, reduces blood flow, and induces in situ thrombosis. Reducing this hyperplastic response has been a long-standing but unrealized goal of biologic researchers in the field. With repeated failures of single target therapies, the redundant response pathways are thought to be a fundamental issue preventing progress towards a solution. Using the current framework, we demonstrate how theoretical genomic manipulations can be introduced into the system to shift the adaptation to a more beneficial phenotype, where the hyperplastic response is mitigated and the risk of thrombosis reduced. Utilizing our previously published rabbit vein graft genomic data, where grafts were harvested at time points ranging from 2 hours to 28 days and under differential flow conditions, and a customized clustering algorithm, five gene clusters that differentiated the low flow (i.e., pro

  13. Applying elastic fibre biology in vascular tissue engineering.

    Science.gov (United States)

    Kielty, Cay M; Stephan, Simon; Sherratt, Michael J; Williamson, Matthew; Shuttleworth, C Adrian

    2007-08-29

    For the treatment of vascular disease, the major cause of death in Western society, there is an urgent need for tissue-engineered, biocompatible, small calibre artery substitutes that restore biological function. Vascular tissue engineering of such grafts involves the development of compliant synthetic or biomaterial scaffolds that incorporate vascular cells and extracellular matrix. Elastic fibres are major structural elements of arterial walls that can enhance vascular graft design and patency. In blood vessels, they endow vessels with the critical property of elastic recoil. They also influence vascular cell behaviour through direct interactions and by regulating growth factor activation. This review addresses physiological elastic fibre assembly and contributions to vessel structure and function, and how elastic fibre biology is now being exploited in small diameter vascular graft design.

  14. Intercalary Reconstruction after Wide Resection of Malignant Bone Tumors of the Lower Extremity Using a Composite Graft with a Devitalized Autograft and a Vascularized Fibula

    Directory of Open Access Journals (Sweden)

    Koichi Ogura

    2015-01-01

    Full Text Available Introduction. Although several intercalary reconstructions after resection of a lower extremity malignant bone tumor are reported, there are no optimal methods which can provide a long-term reconstruction with fewest complications. We present the outcome of reconstruction using a devitalized autograft and a vascularized fibula graft composite. Materials and Methods. We conducted a retrospective review of 11 patients (7 males, 4 females; median age 27 years undergoing reconstruction using a devitalized autograft (pasteurization (n=6, deep freezing (n=5 and a vascularized fibula graft composite for lower extremity malignant bone tumors (femur (n=10, tibia (n=1. Results. The mean period required for callus formation and bone union was 4.4 months and 9.9 months, respectively. Four postoperative complications occurred in 3 patients: 2 infections (1 pasteurized autograft, 1 frozen autograft and 1 fracture and 1 implant failure (both in pasteurized autografts. Graft removal was required in 2 patients with infections. The mean MSTS score was 81% at last follow-up. Conclusions. Although some complications were noted in early cases involving a pasteurized autograft, our novel method involving a combination of a frozen autograft with a vascularized fibula graft and rigid fixation with a locking plate may offer better outcomes than previously reported allografts or devitalized autografts.

  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. Engineered, axially-vascularized osteogenic grafts from human adipose-derived cells to treat avascular necrosis of bone in a rat model.

    Science.gov (United States)

    Ismail, Tarek; Osinga, Rik; Todorov, Atanas; Haumer, Alexander; Tchang, Laurent A; Epple, Christian; Allafi, Nima; Menzi, Nadia; Largo, René D; Kaempfen, Alexandre; Martin, Ivan; Schaefer, Dirk J; Scherberich, Arnaud

    2017-11-01

    Avascular necrosis of bone (AVN) leads to sclerosis and collapse of bone and joints. The standard of care, vascularized bone grafts, is limited by donor site morbidity and restricted availability. The aim of this study was to generate and test engineered, axially vascularized SVF cells-based bone substitutes in a rat model of AVN. SVF cells were isolated from lipoaspirates and cultured onto porous hydroxyapatite scaffolds within a perfusion-based bioreactor system for 5days. The resulting constructs were inserted into devitalized bone cylinders mimicking AVN-affected bone. A ligated vascular bundle was inserted upon subcutaneous implantation of constructs in nude rats. After 1 and 8weeks in vivo, bone formation and vascularization were analyzed. Newly-formed bone was found in 80% of SVF-seeded scaffolds after 8weeks but not in unseeded controls. Human ALU+cells in the bone structures evidenced a direct contribution of SVF cells to bone formation. A higher density of regenerative, M2 macrophages was observed in SVF-seeded constructs. In both experimental groups, devitalized bone was revitalized by vascularized tissue after 8 weeks. SVF cells-based osteogenic constructs revitalized fully necrotic bone in a challenging AVN rat model of clinically-relevant size. SVF cells contributed to accelerated initial vascularization, to bone formation and to recruitment of pro-regenerative endogenous cells. Avascular necrosis (AVN) of bone often requires surgical treatment with autologous bone grafts, which is surgically demanding and restricted by significant donor site morbidity and limited availability. This paper describes a de novo engineered axially-vascularized bone graft substitute and tests the potential to revitalize dead bone and provide efficient new bone formation in a rat model. The engineering of an osteogenic/vasculogenic construct of clinically-relevant size with stromal vascular fraction of human adipose, combined to an arteriovenous bundle is described. This

  17. Towards an intraoperative engineering of osteogenic and vasculogenic grafts from the stromal vascular fraction of human adipose tissue

    Directory of Open Access Journals (Sweden)

    AM Müller

    2010-03-01

    Full Text Available Grafts generated by cultivation of progenitor cells from the stromal vascular fraction of human adipose tissue have been proven to have osteogenic and vasculogenic properties in vivo. However, in vitro manufacture of such implants is challenged by complex, impractical and expensive processes, and requires implantation in a separate surgery. This study investigates the feasibility of an intraoperative approach to engineer cell-based bone grafts with tissue harvest, cell isolation, cell seeding onto a scaffold and subsequent implantation within a few hours. Freshly isolated adipose tissue cells from a total of 11 donors, containing variable fractions of mesenchymal and endothelial progenitors, were embedded at different densities in a fibrin hydrogel, which was wrapped around bone substitute materials based on beta-tricalcium phosphate (ChronOS®, hydroxyapatite (Engipore®, or acellular xenograft (Bio-Oss®. The resulting constructs, generated within 3 hours from biopsy harvest, were immediately implanted ectopically in nude mice and analysed after eight weeks. All explants contained blood vessels formed by human endothelial cells, functionally connected to the recipient’s vasculature. Human origin cells were also found within osteoid structures, positively immunostained for bone sialoprotein and osteocalcin. However, even with the highest loaded cell densities, no frank bone tissue was detected, independently of the material used. These results provide a proof-of-principle that an intraoperative engineering of autologous cell-based vasculogenic bone substitutes is feasible, but highlight that – in the absence of in vitro commitment – additional cues (e.g., low dose of osteogenic factors or orthotopic environmental conditions are likely needed to support complete osteoblastic cell differentiation and bone tissue generation.

  18. An odd application of artificial vascular graft in the kidney transplantation of a patient with severe deep vein thrombosis: a case report.

    Science.gov (United States)

    Mo, M; Peng, L; Yu, S; Gao, C

    2013-09-01

    Transplantation of a living-related donor kidney was performed for a 41-year-old man. The planned right donor nephrectomy from the patient's 64-year-old father was uneventful. However the recipient's bilateral iliac veins and inferior vena cava were occluded, requiring a connection of the donor renal vein to the recipient's right great saphenous vein using an artificial vascular graft. On postoperative day 9, the patient recovered normal renal function with a serum creatinine that gradually decreased to 1.399 mg/dL. Color Doppler and computed tomography angiography imaging showed patency of the artificial vascular graft with no evidence of thrombosis. In addition, warfarin was used to improve his protein S deficiency. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Three-year results following regenerative periodontal surgery of advanced intrabony defects with enamel matrix derivative alone or combined with a synthetic bone graft.

    Science.gov (United States)

    Hoffmann, Thomas; Al-Machot, Elyan; Meyle, Jörg; Jervøe-Storm, Pia-Merete; Jepsen, Søren

    2016-03-01

    This study aims to compare the clinical outcomes of a combination of enamel matrix derivatives (EMD) and a synthetic bone graft (biphasic calcium phosphate) with EMD alone in wide and deep one- and two-wall intrabony defects 36 months after treatment. Thirty patients with chronic periodontitis and one wide (≥ 2 mm) and deep (≥ 4 mm) intrabony defect had been recruited in three centres in Germany. During surgery, defects were randomly assigned to EMD/synthetic bone graft (SBG) (test) or EMD (control). Assessments at baseline, after 6, 12 and 36 months, included bone sounding, relative clinical attachment levels, probing pocket depths and recessions. After 36 months, defects in both groups were significantly improved (p regenerative modalities could be maintained over a period of 3 years. The combination of EMD with SBG did not show any advantage compared to the use of EMD alone.

  20. Emergency Pancreatico-Duodenectomy with Superior Mesenteric and Portal Vein Resection and Reconstruction Using a Gore-Tex Vascular Graft.

    Science.gov (United States)

    Eftimie, Mihai Adrian; Lungu, Vasile; Tudoroiu, Marian; Vatachki, Genady; Batca, Severina; David, Leonard

    2017-01-01

    Emergency pancreatico-duodenectomy(EPD) is a very rare procedure and few reports are present in medical literature. It is an uncommon approach, usually used for emergency surgical treatment of abdominal trauma that involves the head of the pancreas or the duodenum, but it is also a surgical tool for the treatment of ruptured aneurysms, bleeding pseudocysts, duodenal perforations, uncontrollable hemorrhage from ulcers and tumors, severe infectious complications of acute pancreatitis or endoscopic retrograde cholangiopancreatography related complications (1,2). It is rarely used as the first line of treatment in case of acute bleeding from arterial pseudoaneurysm of the cephalad region of the pancreas. We present the case of a bleeding pseudoaneurysm of the cefalic region of the pancreas in a young patient with previously undiagnosed chronic pancreatitis and with suspicion of a malignant process located in the head of the pancreas. We performed a pancreatico-duodenectomy with resection of superior mesenteric and portal vein with reconstruction using Gore-Tex vascular graft due to probable venous abutment. Postoperative course was without any major complications, only minor grad-I pancreatic fistula was present. We determine that EPD is a useful tool in the treatment of such cases. It can be used as a first line of treatment or secondary to endovascular stenting or embolization. Celsius.

  1. 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.

  2. 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.

  3. Development of a pre-vascularized 3D scaffold-hydrogel composite graft using an arterio-venous loop for tissue engineering applications.

    Science.gov (United States)

    Rath, Subha N; Arkudas, Andreas; Lam, Christopher Xf; Olkowski, Radoslaw; Polykandroitis, Elias; Chróscicka, Anna; Beier, Justus P; Horch, Raymund E; Hutmacher, Dietmar W; Kneser, Ulrich

    2012-09-01

    Hyaluronic acid (HA) and fibrin glue (FG) are effective hydrogels for tissue engineering applications as they support tissue in-growth, retain growth factors, and release them slowly with time. The scaffolds, in combination with a hydrogel, effectuate a successful graft. However, the survival of a graft entirely depends upon a functional vascular supply. Therefore, hydrogels must support the in-growing vasculature. To study and compare the vascular patterns, HA and FG hydrogel-containing PLDLLA-TCP-PCL scaffolds were implanted in the groin of male Lewis rats and supplied with a micro-surgically prepared arterio-venous (A-V) loop. The rats were perfused with a vascular contrast media after 4 and 8 weeks and sacrificed for further analysis. The specimens were scanned with micro-CT to find the vascular growth patterns. Corrosion casting of blood vessels followed by SEM demonstrated a high vascular density near the parent blood vessels. Histologically, HA and FG implanted animal groups showed significant angiogenetic activity, especially within the pores of the scaffold. However, formation of new blood vessels was more conspicuously observed at 4 weeks in FG than HA implants. Furthermore, by 8 weeks, the number and pattern of blood vessels were comparable between them. At this time, HA was still present indicating its slow degradation. The finding was confirmed by histomorphometric analysis. This experimental study demonstrates that HA containing composite scaffold systems permit stabile in-growth of blood vessels due to sustained degradation over 8 weeks. HA is a potential matrix for a tissue engineered composite graft.

  4. 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

  5. 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.

  6. The effect of patient age on bone formation using a fully synthetic nanocrystalline bone augmentation material in maxillary sinus grafting.

    Science.gov (United States)

    Wolf, Michael; Wurm, Alexander; Heinemann, Friedhelm; Gerber, Thomas; Reichert, Christoph; Jäger, Andreas; Götz, Werner

    2014-01-01

    Maxillary sinus floor augmentation is a treatment that has been proposed for patients in whom the alveolar bone height is insufficient. This procedure is commonly used in patients aged 40 to 70 years and older. However, little information exists whether the factor of age might influence the outcome of augmentation procedures. The aim of this study was to investigate whether the patient's age has an effect on bone formation and incorporation in maxillary sinus floor augmentation procedures. A fully synthetic nanocrystalline bone augmentation material (NanoBone, Artoss) was used for sinus floor augmentation in patients with a subantral vertical bone height of at least 3 mm and maximum of 7 mm. After 7 months healing time, biopsy specimens were taken and were divided into two groups according to the patient's age. Exclusion criteria were poor general health (eg, severe renal/and or liver disease), history of a radiotherapy in the head region, chemotherapy at the time of surgical procedure, noncompensated diabetes mellitus, symptoms of a maxillary sinus disease, active periodontal or systemic diseases, smoking, and poor oral hygiene. Histologic analyses with hematoxylin-eosin stain were performed. Multinucleated osteoclast-like cells were identified by histochemical staining (tartrate-resistant acid phosphatase [TRAP]). Quantitative and age-dependent assessment of bone formation, residual bone grafting material, and soft tissue formation following sinus augmentation was performed using histomorphometric analysis and the Bonferroni adjustment of the Student t test. Twenty biopsy specimens from 17 patients were taken and divided into two groups according to age (group 1: 41 to 52 years; group 2: 66 to 71 years) containing 10 specimens each, which were analyzed in triplicate resulting in a total of 30 specimens per group. A regeneration process with varying amounts of newly formed bone surrounded by marrow-like tissue was present in all augmented regions. No signs of

  7. Histologic Evaluation of Critical Size Defect Healing With Natural and Synthetic Bone Grafts in the Pigeon ( Columba livia ) Ulna.

    Science.gov (United States)

    Tunio, Ahmed; Jalila, Abu; Goh, Yong Meng; Shameha-Intan; Shanthi, Ganabadi

    2015-06-01

    Fracture and bone segment loss are major clinical problems in birds. Achieving bone formation and clinical union in a fracture case is important for the survival of the bird. To evaluate the efficacy of bone grafts for defect healing in birds, 2 different bone grafts were investigated in the healing of a bone defect in 24 healthy pigeons ( Columba livia ). In each bird, a 1-cm critical size defect (CSD) was created in the left ulna, and the fracture was stabilized with external skeletal fixation (ESF). A graft of hydroxyapatite (HA) alone (n = 12 birds) or demineralized bone matrix (DBM) combined with HA (n = 12 birds) was implanted in the CSD. The CSD healing was evaluated at 3 endpoints: 3, 6, and 12 weeks after surgery. Four birds were euthanatized at each endpoint from each treatment group, and bone graft healing in the ulna CSD was evaluated by histologic examination. The CSD and graft implants were evaluated for quality of union, cortex development, and bone graft incorporation. Results showed no graft rejection in any bird, and all birds had connective tissue formation in the defect because of the bone graft application. These results suggest that bone defect healing can be achieved by a combination of osteoinductive and osteoconductive bone graft materials for clinical union and new bone regeneration in birds. The combination of DBM and HA resulted in a better quality bone graft (P < .05) than did HA alone, but there was no significant differences in cortex development or bone graft incorporation at 3, 6, or 12 weeks. From the results of this study, we conclude that HA bone grafts, alone or in combination with DBM, with external skeletal fixation is suitable and safe for bone defect and fracture treatment in pigeons.

  8. Proteomic analysis of vascular smooth muscle cells in physiological condition and in pulmonary arterial hypertension: Toward contractile versus synthetic phenotypes.

    Science.gov (United States)

    Régent, Alexis; Ly, Kim Heang; Lofek, Sébastien; Clary, Guilhem; Tamby, Mathieu; Tamas, Nicolas; Federici, Christian; Broussard, Cédric; Chafey, Philippe; Liaudet-Coopman, Emmanuelle; Humbert, Marc; Perros, Frédéric; Mouthon, Luc

    2016-10-01

    Vascular smooth muscle cells (VSMCs) are highly specialized cells that regulate vascular tone and participate in vessel remodeling in physiological and pathological conditions. It is unclear why certain vascular pathologies involve one type of vessel and spare others. Our objective was to compare the proteomes of normal human VSMC from aorta (human aortic smooth muscle cells, HAoSMC), umbilical artery (human umbilical artery smooth muscle cells, HUASMC), pulmonary artery (HPASMC), or pulmonary artery VSMC from patients with pulmonary arterial hypertension (PAH-SMC). Proteomes of VSMC were compared by 2D DIGE and MS. Only 19 proteins were differentially expressed between HAoSMC and HPASMC while 132 and 124 were differentially expressed between HUASMC and HAoSMC or HPASMC, respectively (fold change 1.5≤ or -1.5≥, p < 0.05). As much as 336 proteins were differentially expressed between HPASMC and PAH-SMC (fold change 1.5≤ or -1.5≥, p < 0.05). HUASMC expressed increased amount of α-smooth muscle actin compared to either HPASMC or HAoSMC (although not statistically significant). In addition, PAH-SMC expressed decreased amount of smooth muscle myosin heavy chain and proliferation rate was increased compared to HPASMC thus supporting that PAH-SMC have a more synthetic phenotype. Analysis with Ingenuity identified paxillin and (embryonic lethal, abnormal vision, drosophila) like 1 (ELAVL1) as molecules linked with a lot of proteins differentially expressed between HPASMC and PAH-SMC. There was a trend toward reduced proliferation of PAH-SMC with paxillin-si-RNA and increased proliferation with ELAVL1-siRNA. Thus, VSMCs have very diverse protein content depending on their origin and this is in link with phenotypic differentiation. Paxillin targeting may be a promising treatment of PAH. ELAVL1 also participate in the regulation of PAH-SMC proliferation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  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. Synthetic

    Directory of Open Access Journals (Sweden)

    Anna Maria Manferdini

    2010-06-01

    Full Text Available Traditionally materials have been associated with a series of physical properties that can be used as inputs to production and manufacturing. Recently we witnessed an interest in materials considered not only as ‘true matter’, but also as new breeds where geometry, texture, tooling and finish are able to provoke new sensations when they are applied to a substance. These artificial materials can be described as synthetic because they are the outcome of various qualities that are not necessarily true to the original matter, but they are the combination of two or more parts, whether by design or by natural processes. The aim of this paper is to investigate the potential of architectural surfaces to produce effects through the invention of new breeds of artificial matter, using micro-scale details derived from Nature as an inspiration.

  11. Treatment of osteonecrosis of the femoral head with free vascularized fibular grafting: Results of 7.6-year follow-up.

    Science.gov (United States)

    Ünal, Mehmet Bekir; Cansu, Eren; Parmaksızoğlu, Fatih; Cift, Hakan; Gürcan, Serkan

    2016-10-01

    The aim of this study was to determine long term follow up of the patients who had femoral head osteonecrosis and had been treated with free vascularized fibular grafting. We retrospectively reviewed 28 hips of 21 patients who had undergone free vascularized fibular grafting for the treatment of osteonecrosis of femoral head. There were 16 male and 5 female patients. The mean age of the patients at the time of surgery was 30.7 years (between 15 and 53 years). The mean follow-up time was 7.6 years (between 5 years and 9.2 years). During follow-up, one patient died because of leukemia, and one patient was lost. The remaining 26 hips of 19 patients were evaluated. According to the Ficat classification, at the time of surgery, 17 hips were in grade 2 and 9 hips were in grade 3. The post-operative Harris hip scores in grade II disease were excellent in 12 patients, good in 3 patients, and fair in 1 patient. In grade III disease, 1 patient was excellent, 5 patients were good, and 1 patient was fair. There was a significant increase in HHS scores (61 ± 9.7 vs 84 ± 17.8, p < 0.001). Free vascularized fibular grafting yields extremely good results, particularly in pre-collapse stages of disease in young patients. The operation time does not mark increased if the surgical team is "familiar" with the procedure, and the residual fibular defect of the donor site does not impair the functions of daily living. Level IV, Therapeutic study. Copyright © 2016. Production and hosting by Elsevier B.V.

  12. Injectable synthetic bone graft substitute combined with core decompression in the treatment of advanced osteonecrosis of the femoral head: A 5-year follow-up.

    Science.gov (United States)

    Yu, Pei-An; Peng, Kuo-Ti; Huang, Tsan-Weng; Hsu, Robert Wen-Wei; Hsu, Wei-Hsiu; Lee, Mel S

    2015-01-01

    Osteonecrosis of the femoral head can lead to destruction of the hip joint and disabling arthritis in young adults, if left untreated. Among the salvage procedures, core decompression combined with bone graft substitutes is a viable option for joint preservation. The purpose of this study was to review the outcomes of using synthetic bone graft substitute (calcium sulfate and calcium phosphate) for the treatment of late-stage osteonecrosis of the femoral head. From November 2008 to May 2009, 19 hips in 18 patients with osteonecrosis of the femoral head [6 hips in Association Research Circulation Osseous (ARCO) stage IIC and 13 hips in stage IIIA] were treated with core decompression combined with PRO-DENSE™ (Injectable Regenerative Graft). The average age of the patients at the time of surgery was 48 years (range 25-67 years). Twelve patients (13 hips) overused alcohol, four patients (4 hips) were idiopathic, one patient (1 hip) used corticosteroids, and one patient (1 hip) was post-traumatic. The clinical failure was defined as conversion to total hip arthroplasty or progression in head collapse. At the conclusion of the study, 3 in the 6 stage IIC hips and 8 in the 13 stage IIIA hips were converted to total hip arthroplasty in an average of 8.5 months (range 4-30 months) postoperatively. Advanced collapse of the femoral head awaiting for total hip arthroplasty was observed in the other six hips. Of the 19 hips, only 2 hips (10.5%) survived without further collapse in the 5-year follow-up. This resulted in 89.5% failure rate with early resorption of the grafting in an average of 5.3 months. Core decompression combined with an injectable calcium sulfate and calcium phosphate composite graft (PRO-DENSE) were associated high failure rates in the early postoperative period. It is not recommended for the treatment of ARCO stage IIC and IIIA osteonecrosis of the femoral head.

  13. The usefulness of postoperative pinhole bone scintigraphy in the assessment of prognosis after multiple drilling or vascularized bone graft in patients with avascular necrosis of femoral head

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Young An; Kim, Sung Hoon; Cheon, Kyung Ah; Park, Young Ha; Jeong, Soo Kyo [College of Medicine, The Catholic Univ., Seoul (Korea, Republic of); Song Moon Kab [Eulji Medical Center, Taejon (Korea, Republic of)

    1999-08-01

    It is important to evaluate the healing process of avascular necrosis (AVN) involving femoral head after treatment. The purpose of this study was to assess the usefulness of pinhole bone scintigraphy in the AVN of femoral head after surgery. We analyzed the changing pattern of pinhole bone scintigram in 21 femoral heads of 16 patients (14 lesions/11 male, 7 lesions/5 female, mean age : 39.4 yrs) before and after multiple drilling or vascularized bone grafting for AVN of the femoral head. In all patients, pre-operative scintigrams were obtained at 1 to 3 months before treatment and the first post-operative scintigrams were obtained at 1 to 3 months after treatment. All patients were followed for 2 to 4 years after operation. The findings of the pinhole scintigrams were divided into three patterns: 1) curvilinear, 2) scattered spotty and 3) underdetermined. The 10 of 11 lesions with curvilinear pattern had good postoperative clinical and radiological follow-up findings. However, all 6 lesions with scattered spotty pattern showed poor postoperative findings, which necessitated total hip joint replacement. Of the 4 lesions with undetermined pattern, 2 required total hip joint replacement. There was significant difference in postoperative prognosis between the curvilinear and scattered spotty patterns (p<0.05). We conclude that the pattern of pinhole bone scintigram obtained within 1 to 3 months after multiple drilling or vascularized bone graft operation is a useful prognostic indicator in the AVN of femoral head.

  14. 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.

  15. 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

  16. Osteomyelitis of the First Metatarsal Head Treated With Joint-Preserving Surgery and a Synthetic Resorbable Bone Graft Substitute: A Case Report.

    Science.gov (United States)

    Anagnostakos, Konstantinos; Koch, Katrin

    2018-04-11

    Managing infections of the first metatarsophalangeal joint can be demanding because many patients present with late-stage infection and partial or total amputation of the first ray or the phalanx could be necessary. We describe such a patient who was successfully treated with a calcium-based resorbable bone substitute that preserved the first metatarsophalangeal joint. A 38-year-old female presented to our department with a foot infection. Examination revealed a methicillin-susceptible Staphylococcus aureus infection of the first metatarsophalangeal joint. The histopathologic findings confirmed active osteomyelitis of the first metatarsal head. The metatarsophalangeal joint was debrided with open synovectomy, the metatarsal head was curetted, and the bone defect was filled with 2 mL of a synthetic bone graft substitute. Two years later, she reported no problems with function or pain, the joint had full range of motion, and she had no local or systemic signs of infection. The most recent radiographs revealed no damage to the first metatarsophalangeal joint. A synthetic bone graft substitute can be a good alternative for treating forefoot infections when the soft tissues are intact and the bone defect is not so large that partial or full amputation is necessary. Copyright © 2017 The American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  17. Core Decompression with Synthetic Grafting as a Joint Preservation Strategy in Humeral Avascular Necrosis Due to Sickle Cell Anemia: A Case Report.

    Science.gov (United States)

    Steffensmeier, Andrew M; Kirkham, Karen; Wiemann, John M

    2016-01-01

    Avascular necrosis (AVN) of the femoral or humeral heads in patients with sickle cell anemia is a common and painful condition. There is currently no gold standard treatment protocol for this condition. Typically, the pain is managed with narcotics and activity restriction until there has been collapse of the subchondral bone with a degree of arthrosis sufficient to warrant total joint arthroplasty. This method entails prolonged pain for the patient and decreases the ability to function occupationally and recreationally. A 51-year-old African-American woman with a history of sickle cell anemia presented for the evaluation of significant bilateral shoulder pain that was confirmed to be AVN via radiographs and magnetic resonance imaging of both her humeral heads without joint collapse. She tried and failed conservative management with physical therapy and optimization of sickle cell treatment with pain medications for years, so she desired surgical management. Arthroscopically assisted core decompression of her humeral heads with synthetic grafting was performed in an attempt at joint preservation. This report demonstrates a technique of staged decompression of necrotic bone in the bilateral humeral heads with synthetic bone grafting to determine if this could function as a joint preservation strategy. This procedure was considered successful to alleviate the patients' pain in both of her arms. The application of this procedure is significant because it could be used in various future medical joint preservation cases for a wide range of patients.

  18. Distal embolization during native vessel and vein graft coronary intervention with a vascular protection device: predictors of high-risk lesions.

    Science.gov (United States)

    El-Jack, Seif S; Suwatchai, Pornratanarangsi; Stewart, James T; Ruygrok, Peter N; Ormiston, John A; West, Teena; Webster, Mark W I

    2007-12-01

    We sought to define clinical and angiographic variables that may predict patients and lesions at increased risk for distal embolism during percutaneous intervention (PCI), as assessed by debris retrieval from a distal-protection filter device. Distal thrombo- and atheroembolism may contribute to periprocedural myocardial necrosis during PCI, which may in turn affect long-term outcomes. Distal protection devices have been used to reduce this occurrence with variable outcomes depending on lesion and patient subsets. 194 consecutive patients in whom the FilterWire(R) device (FW) [Boston Scientific Corp., Natick, MA] was used for native coronary vessel (n =129) or vein graft (n = 65) PCI were studied. FW debris was visually analyzed using a semi-quantitative grading score. Patients with "significant" debris (particles > or = 1 mm diameter) were compared with those with "nonsignificant" debris (no debris or particles <1 mm) with respect to clinical (age, gender, coronary disease risk factors, clinical presentation, periprocedural medications), and angiographic (vessel treated, vessel size, lesion length, lesion characteristics, angiographic thrombus and TIMI flow before and after PCI) variables. Significant debris was retrieved in 55% of patients, more frequently from vein graft (69%) than native vessel lesions (48%, p = 0.006). No clinical characteristics predicted significant debris retrieval. Angiographic predictors of significant debris by multivariate analysis were longer stent length and final TIMI flow <3 (p = 0.009 and 0.007, respectively). Longer stent length, likely reflecting increased lesion length and plaque burden, predicted significant distal embolism during PCI in native vessel and vein graft lesions, as assessed by debris collected in a distal vascular protection device. This suggests that use of vascular protection devices should be considered during PCI of long lesions.

  19. Immunological challenges associated with artificial skin grafts: available solutions and stem cells in future design of synthetic skin.

    Science.gov (United States)

    Dixit, Saurabh; Baganizi, Dieudonné R; Sahu, Rajnish; Dosunmu, Ejowke; Chaudhari, Atul; Vig, Komal; Pillai, Shreekumar R; Singh, Shree R; Dennis, Vida A

    2017-01-01

    The repair or replacement of damaged skins is still an important, challenging public health problem. Immune acceptance and long-term survival of skin grafts represent the major problem to overcome in grafting given that in most situations autografts cannot be used. The emergence of artificial skin substitutes provides alternative treatment with the capacity to reduce the dependency on the increasing demand of cadaver skin grafts. Over the years, considerable research efforts have focused on strategies for skin repair or permanent skin graft transplantations. Available skin substitutes include pre- or post-transplantation treatments of donor cells, stem cell-based therapies, and skin equivalents composed of bio-engineered acellular or cellular skin substitutes. However, skin substitutes are still prone to immunological rejection, and as such, there is currently no skin substitute available to overcome this phenomenon. This review focuses on the mechanisms of skin rejection and tolerance induction and outlines in detail current available strategies and alternatives that may allow achieving full-thickness skin replacement and repair.

  20. [The use of a synthetic vascular artificial prosthesis or arterial homograft in cases of patients with the arteriosclerosis and terminal insufficiency of kidney cured by the kidney transplantation].

    Science.gov (United States)

    Pupka, Artur; Blocher, Dariusz; Staniszewski, Tomasz; Płonek, Tomasz; Bogdan, Justyna

    2009-01-01

    Arterial transplantations were practiced in the vascular surgery since the beginning of her formation but without successes in the distant observation. Transplantation of a kidney is a routine conduct in the treatment of the decadent incapacity of a kidney. The dissertation concerns a use of arterial allografts kept using a method of a cold ischaemia in the protective liquid or synthetic vascular dacron artificial limbs or PTFE used as arterial foot-bridges at patients with the atherosclerotic obstruction aortal-pelvic, treated with the kidney transplantation. The arterial transplant is created from the aorta, arteria iliacas common and externa, femoral arteries common and superficial. A tissue material is kept using the method of the cold ischaemia and practical as the aortal foot-bridge-femoral or aortal-two-femoral at classified earlier patients being subjecteds to transfusion. The other way of a transplantation of a kidney at patients with the arteriosclerosis is the realization earlier or one-temporarily the vascular foot-bridge with use of the synthetic artificial limb. It seems that vascular artificial limbs about enlarged resistance on the contagion should be used in such a case. Sonographic examinations with duplex doppler and angiography are performed in all cases. The analysis of such cures can make a creation of the most profitable algorithm of the conduct possible in cases of patients suffering from ischaemia of lower limbs and requiring a transplantation of a kidney because of its incapacity.

  1. Reconstruction of the Midfoot Using a Free Vascularized Fibular Graft After En Bloc Excision for Giant Cell Tumor of the Tarsal Bones: A Case Report.

    Science.gov (United States)

    Hara, Hitomi; Kawamoto, Teruya; Onishi, Yasuo; Fujioka, Hiroyuki; Nishida, Kotaro; Kuroda, Ryosuke; Kurosaka, Masahiro; Akisue, Toshihiro

    2016-01-01

    We report the case of a 32-year-old Japanese female with a giant cell tumor of bone involving multiple midfoot bones. Giant cell tumors of bone account for approximately 5% of all primary bone tumors and most often arise at the ends of long bones. The small bones, such as those of the hands and feet, are rare sites for giant cell tumors. Giant cell tumors of the small bones tend to exhibit more aggressive clinical behavior than those of the long bones. The present patient underwent en bloc tumor excision involving multiple tarsals and metatarsals. We reconstructed the longitudinal arch of the foot with a free vascularized fibular graft. At the 2-year follow-up visit, bony union had been achieved, with no tumor recurrence. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  2. Comparison of in vitro and in vivo bioactivity: cuttlefish-bone-derived hydroxyapatite and synthetic hydroxyapatite granules as a bone graft substitute.

    Science.gov (United States)

    Kim, Beom-Su; Kang, Hyo Jin; Yang, Sun-Sik; Lee, Jun

    2014-04-01

    Bone reconstruction in clinical settings often requires bone substitutes. Hydroxyapatite (HAp) is a widely used bone substitute due to its osteoconductive properties and bone bonding ability. The aim of this study was to evaluate HAp granules derived from cuttlefish bone (CB-HAp) as a substitute biomaterial for bone grafts. In this study, HAp granules were prepared from raw CB by using a hydrothermal reaction. The formation of HAp from CB was confirmed by scanning electron microscopy and x-ray diffraction analysis. The bioactivity of the CB-HAp granules was evaluated both in vitro and in vivo. Our results show that CB-HAp is non-toxic and that CB-HAp granules supported improved cell adhesion, proliferation and differentiation compared to stoichiometric synthetic HAp granules. Furthermore, in vivo bone defect healing experiments show that the formation of bone with CB-HAp is higher than that with pure HAp. These results show that CB-HAp granules have excellent potential for use as a bone graft material.

  3. Osseointegration of dental implants in 3D-printed synthetic onlay grafts customized according to bone metabolic activity in recipient site.

    Science.gov (United States)

    Tamimi, Faleh; Torres, Jesus; Al-Abedalla, Khadijeh; Lopez-Cabarcos, Enrique; Alkhraisat, Mohammad H; Bassett, David C; Gbureck, Uwe; Barralet, Jake E

    2014-07-01

    Onlay grafts made of monolithic microporous monetite bioresorbable bioceramics have the capacity to conduct bone augmentation. However, there is heterogeneity in the graft behaviour in vivo that seems to correlate with the host anatomy. In this study, we sought to investigate the metabolic activity of the regenerated bone in monolithic monetite onlays by using positron emission tomography-computed tomography (PET-CT) in rats. This information was used to optimize the design of monetite onlays with different macroporous architecture that were then fabricated using a 3D-printing technique. In vivo, bone augmentation was attempted with these customized onlays in rabbits. PET-CT findings demonstrated that bone metabolism in the calvarial bone showed higher activity in the inferior and lateral areas of the onlays. Histological observations revealed higher bone volume (up to 47%), less heterogeneity and more implant osseointegration (up to 38%) in the augmented bone with the customized monetite onlays. Our results demonstrated for the first time that it is possible to achieve osseointegration of dental implants in bone augmented with 3D-printed synthetic onlays. It was also observed that designing the macropore geometry according to the bone metabolic activity was a key parameter in increasing the volume of bone augmented within monetite onlays. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Sequential Use of Hyperbaric Oxygen, Synthetic Skin Substitute and Skin Grafting in the Treatment of a Refractory Vasculitic Ulcer.

    Science.gov (United States)

    Akcali, Gökhan; Uzun, Günalp; Yapici, Abdül Kerim; Yildiz, Şenol

    2013-12-01

    Cutaneous leukocytoclastic vasculitis (CLCV) is a disorder characterized by the inflammation of the small vessels of the skin. CLCV may cause recurrent, drug-resistant, non-healing ulcers. Herein, we present a patient with a recalcitrant ulcer caused by CLCV, who was successfully treated with hyperbaric oxygen therapy and skin grafting. There is not any particular therapy/product that will heal all type of wounds. We can achieve better results provided that wound care products and advanced treatments are used at the right time.

  5. Adhesion, Growth, and Maturation of Vascular Smooth Muscle Cells on Low-Density Polyethylene Grafted with Bioactive Substances

    Czech Academy of Sciences Publication Activity Database

    Pařízek, Martin; Kasálková-Slepičková, N.; Bačáková, Lucie; Švindrych, Zdeněk; Slepička, P.; Bačáková, Markéta; Lisá, Věra; Švorčík, V.

    2013-01-01

    Roč. 2013, č. 2013 (2013), s. 371430 ISSN 2314-6133 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:67985823 Keywords : biotechnology * tissue replacements * vascular smooth muscle cells * adhesion * modification Subject RIV: JJ - Other Materials

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Equilibrium shift in solution: molecular shape recognition and precipitation of a synthetic double helix using helicene-grafted silica nanoparticles.

    Science.gov (United States)

    Miyagawa, Masamichi; Ichinose, Wataru; Yamaguchi, Masahiko

    2014-01-27

    Chiral silica nanoparticles (70 nm) grafted with (P)-helicene recognized the molecular shape of double helix and random coil (P)-ethynylhelicene oligomers in solution. A mixture of the (P)-nanoparticles and double helix precipitated much faster than a mixture of the (P)-nanoparticles and random coil, and the precipitate contained only the double helix. The mixture of the (P)-nanoparticles and (P)-ethynylhelicene pentamer reversibly dispersed in trifluoromethylbenzene upon heating at 70 °C and precipitated upon cooling at 25 °C. When a 10:90 equilibrium mixture of the double helix and random coil in solution was treated with the (P)-nanoparticles, the double helix was precipitated in 53% yield and was accompanied by equilibrium shift. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Construction and characterization of an electrospun tubular scaffold for small-diameter tissue-engineered vascular grafts: a scaffold membrane approach.

    Science.gov (United States)

    Hu, Jin-Jia; Chao, Wei-Chih; Lee, Pei-Yuan; Huang, Chih-Hao

    2012-09-01

    Based on a postulate that the microstructure of a scaffold can influence that of the resulting tissue and hence its mechanical behavior, we fabricated a small-diameter tubular scaffold (∼3 mm inner diameter) that has a microstructure similar to the arterial media using a scaffold membrane approach. Scaffold membranes that contain randomly oriented, moderately aligned, or highly aligned fibers were fabricated by collecting electrospun poly([epsilon]-caprolactone) fibers on a grounded rotating drum at three different drum rotation speeds (250, 1000, and 1500 rpm). Membranes of each type were wrapped around a small-diameter mandrel to form the tubular scaffolds. Particularly, the tubular scaffolds with three different off-axis fiber angles (30, 45, and 60 degree) were formed using membranes that contain aligned fibers. These scaffolds were subjected to biaxial mechanical testing to examine the effects of fiber directions as well as the distribution of fiber orientations on their mechanical properties. The circumferential elastic modulus of the tubular scaffold was closely related to the fiber directions; the larger the off-axis fiber angle the greater the circumferential elastic modulus. The distribution of fiber orientations, on the other hand, manifested itself in the mechanical behavior via the Poisson effect. Similar to cell sheet-based vascular tissue engineering, tubular cell-seeded constructs were prepared by wrapping cell-seeded scaffold membranes, alleviating the difficulty associated with cell seeding in electrospun scaffolds. Histology of the construct illustrated that cells were aligned to the fiber directions in the construct, demonstrating the potential to control the microstructure of tissue-engineered vascular grafts using the electrospun scaffold membrane. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Long-term results of PTFE grafts.

    Science.gov (United States)

    Hedin, Ulf

    2015-01-01

    Vascular surgeons are essential in "lifeline" creation for hemodialysis patients and should be the central player in any multidisciplinary access service together with nephrologists, dialysis staff and interventional radiology. In this position, access surgeons are involved in complicated clinical decision making regarding primary and secondary access selection, which throughout the last decade has been largely aided, and influenced, by national and international guidelines as well as other initiatives. These recommendations, unanimously and appropriately, advocate the placement of native fistulas over synthetic grafts (the majority grafts from expanded polytetrafluoroethylene, ePTFE, herein referred to as PTFE) based on the superiority of fistulas with respect to complications such as infections and thrombosis. Nevertheless, the use of PTFE grafts for hemodialysis access is an accepted and firmly established alternative to native fistulas where data today reveal unwanted consequences to overinterpretation of established guidelines such as increased catheter use. This information highlights a need for an adjustment of access selection strategies based on patient-centered algorithms. Here, available results on PTFE graft performance in hemodialysis access is recapitulated, with respect to both conventional grafts and technical modifications, and conclude with a modified approach to primary access selection.

  13. Electron microscopy study of a vascular prosthesis destructed in vivo reveals fractures in Dacron fibers.

    Science.gov (United States)

    Woźniak, Witold; Olszewski, Wojciech; Górski, Grzegorz

    2016-02-01

    The genuine destruction of a synthetic prosthesis wall, as a late complication of vascular surgery, is extremely rare. We report a case of a 64-year-old male who had his 12-year-old femoropopliteal synthetic graft explanted due to two large pseudoaneurysms in the middle section of the graft. Microscopic evaluation demonstrated the areas of focal thinning along the entire prosthesis wall, with "foreign body" type reaction in the adjacent connective tissue. Transmission electron microscopy showed longitudinal fractures of Dacron fibers interposed with cellular structures, suggesting that destruction must have taken place significantly earlier. The problems of limited graft durability and graft surveillance are discussed. © The Author(s) 2015.

  14. Addition of a Synthetically Fabricated Osteoinductive Biphasic Calcium Phosphate Bone Graft to BMP2 Improves New Bone Formation.

    Science.gov (United States)

    Zhang, Yufeng; Yang, Shuang; Zhou, Wei; Fu, Hang; Qian, Li; Miron, Richard J

    2016-12-01

    time was observed for collagen scaffolds up to 14 days. The osteoinductive properties of BMP2 may further be enhanced by its combination with a novel synthetically fabricated osteoinductive BCP scaffold. Future clinical testing is required to further assess these preliminary findings. © 2015 Wiley Periodicals, Inc.

  15. Synthetic peptide, Ala-Arg-Glu-Gly-Glu-Met, abolishes pro-proliferative and anti-apoptotic effects of high glucose in vascular smooth muscle cells.

    Science.gov (United States)

    Cao, Xiaozhou; Lyu, Yi; Ning, Junyu; Tang, Xiaozhi; Shen, Xinchun

    2017-03-25

    Apoptosis plays a critical role in normal vascular development and atherosclerosis. However, high glucose has been reported to generate a certain level of ROS that can inhibit vascular smooth muscle cell (VSMC) apoptosis, with the underlying mechanism remaining unclear. In this study, a synthetic peptide AREGEM (Ala-Arg-Glu-Gly-Glu-Met) exhibited antioxidative effects and was used to investigate its function in VSMCs during hyperglycaemia. MTT assay results demonstrated that AREGEM significantly attenuated high glucose-induced VSMCs proliferation. Flow cytometry displayed that high glucose levels inhibited cell apoptosis, whereas this effect was attenuated by pre-incubation with AREGEM. In addition, the 2',7'-dichlorofluorescein diacetate (DCFH-DA) fluorescent probe assay further demonstrated that AREGEM reduced intracellular ROS accumulation in VSMCs. Furthermore, this peptide was able to prevent the decrease of caspase-3 activity and the increase of the ratio of Bcl-2/Bax protein in VSMCs exposed to high glucose. These findings demonstrated that AREGEM is able to abolish the effects of high glucose in VSMCs; therefore, this peptide can be a potential candidate to develop a novel strategy for curing diabetic related diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Activity ranking of synthetic analogs targeting vascular endothelial growth factor receptor 2 by an integrated cell membrane chromatography system.

    Science.gov (United States)

    Wang, Dongyao; Lv, Diya; Chen, Xiaofei; Liu, Yue; Ding, Xuan; Jia, Dan; Chen, Langdong; Zhu, Zhenyu; Cao, Yan; Chai, Yifeng

    2015-12-01

    Evaluating the biological activities of small molecules represents an important part of the drug discovery process. Cell membrane chromatography (CMC) is a well-developed biological chromatographic technique. In this study, we have developed combined SMMC-7721/CMC and HepG2/CMC with high-performance liquid chromatography and time-of-flight mass spectrometry to establish an integrated screening platform. These systems was subsequently validated and used for evaluating the activity of quinazoline compounds, which were designed and synthesized to target vascular endothelial growth factor receptor 2. The inhibitory activities of these compounds towards this receptor were also tested using a classical caliper mobility shift assay. The results revealed a significant correlation between these two methods (R(2) = 0.9565 or 0.9420) for evaluating the activities of these compounds. Compared with traditional methods of evaluating the activities analogous compounds, this integrated cell membrane chromatography screening system took less time and was more cost effective, indicating that it could be used as a practical method in drug discovery. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Retrosternal friction-induced late disruption of the anastomotic site between Bentall's valved conduit and an aortic arch graft: report of a case.

    Science.gov (United States)

    Fukada, Johji; Morishita, Kiyofumi; Kawaharada, Nobuyoshi; Kurimoto, Yoshihiko; Muraki, Satoshi; Satsu, Takuma; Abe, Tomio

    2003-01-01

    We report a case of late mediastinal false aneurysm originating from disruption of the suture line between synthetic vascular grafts for aortic root and total aortic arch replacements. This aneurysm developed without any infection in a patient with Marfan's syndrome. To our knowledge, this event has never been reported before. The only possible cause of this disruption was that the monofilament suture was broken by continuous friction between the pointed anastomotic line and the sternum since the operation. The treatment options for this unusual event after extended synthetic graft replacement are discussed.

  18. Shh mediates PDGF-induced contractile-to-synthetic phenotypic modulation in vascular smooth muscle cells through regulation of KLF4

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Qiu [Department of Vascular Surgery, 1st Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Wei, Bin [Department of Dermatology, 1st Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Zhao, Yu; Wang, Xuehu; Fu, Qining; Liu, Hong [Department of Vascular Surgery, 1st Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China); Li, Fenghe, E-mail: lfh_cmu@126.com [Department of Vascular Surgery, 1st Affiliated Hospital of Chongqing Medical University, Chongqing 400016 (China)

    2016-07-01

    Platelet-derived growth factor (PDGF) is known to induce phenotypic switching of vascular smooth muscle cells (VSMCs) from contractile to a pathological synthetic state, which played an essential role in proliferation of VSMCs. Sonic hedgehog (Shh) contributes to the proliferation of VSMCs when induced by PDGF. Here, we investigated the probable role of Shh in PDGF-induced VSMC dedifferentiation and its underlying mechanisms. We found that PDGF stimulated Shh expression in VSMCs, which was mediated by activation of PDGFRβ/ERK1/2 cell signaling pathway. Further, we found PDGF-induced VSMC phenotypic modulation was accompanied by up-regulation of Shh/Gli family zinc finger 2 (Gli2) signaling and Krüppel-like factor 4 (KLF4). When inhibited Shh in the presence of PDGF, the expressions of KLF4 and VSMC dedifferentiation markers were down-regulated and the effect of PDGF in inducing VSMC dedifferentiation was blocked. In the absence of PDGF, Shh signaling activation increased the expression of KLF4 and promoted VSMC dedifferentiation. The results indicate Shh participated in the regulation of PDGF-induced VSMC dedifferentiation. Finally, we found that KLF4 was closely involved in this process. On inhibition of KLF4, PDGF induced VSMC dedifferentiation was abrogated, even in the presence of Shh. Taken together, the results provide critical insights into the newly discovered role of Shh in phenotypic modulation of VSMCs which depends on KLF4. - Highlights: • Shh as a downstream effector of PDGF participates in PDGF-induced VSMC phenotypic modulation. • Shh can promote VSMC phenotypic switching from contractile to synthetic state. • Shh mediates VSMC phenotypic modulation through regulation of KLF4.

  19. Aortic Graft Infection Secondary to Iatrogenic Transcolonic Graft Malposition.

    Science.gov (United States)

    Blank, Jacqueline J; Rothstein, Abby E; Lee, Cheong Jun; Malinowski, Michael J; Lewis, Brian D; Ridolfi, Timothy J; Otterson, Mary F

    2018-01-01

    Aortic graft infections are a rare but devastating complication of aortic revascularization. Often infections occur due to contamination at the time of surgery. Iatrogenic misplacement of the limbs of an aortobifemoral graft is exceedingly rare, and principles of evaluation and treatment are not well defined. We report 2 cases of aortobifemoral bypass graft malposition through the colon. Case 1 is a 54-year-old male who underwent aortobifemoral bypass grafting for acute limb ischemia. He had previously undergone a partial sigmoid colectomy for diverticulitis. Approximately 6 months after vascular surgery, he presented with an occult graft infection. Preoperative imaging and intraoperative findings were consistent with graft placement through the sigmoid colon. Case 2 is a 60-year-old male who underwent aortobifemoral bypass grafting due to a nonhealing wound after toe amputation. His postoperative course was complicated by pneumonia, bacteremia thought to be secondary to the pneumonia, general malaise, and persistent fevers. Approximately 10 weeks after the vascular surgery, he presented with imaging and intraoperative findings of graft malposition through the cecum. Aortic graft infection is usually caused by surgical contamination and presents as an indolent infection. Case 1 presented as such; Case 2 presented more acutely. Both grafts were iatrogenically misplaced through the colon at the index operation. The patients underwent extra-anatomic bypass and graft explantation and subsequently recovered.

  20. A novel microporous polyurethane vascular graft: in vivo evaluation of the UTA prosthesis implanted as infra-renal aortic substitute in dogs.

    Science.gov (United States)

    Marois, Y; Akoum, A; King, M; Guidoin, R; von Maltzahn, W; Kowligi, R; Eberhart, R C; Teijeira, F J; Verreault, J

    1993-01-01

    A novel microporous polyurethane blood conduit developed at the University of Texas at Arlington was implanted as an infra-renal substitute in dogs. The prosthesis was fabricated by precipitating a solution of the polymer with dry nitrogen onto a rotating mandrel. The grafts were sterilized either by gamma radiation (series I) or ethylene oxide (series II); they were implanted for the following prescheduled periods: 4, 24, 48 hours, and 1 week (short-term) and 2, 4 weeks, 3 and 6 months (medium-term). The thrombohematological characteristics of each animal were evaluated prior to implantation and confirmed that the index of blood coagulability was normal. In the short-term group, five out of eight grafts were patent and three were partially occluded; four grafts in the medium-term group were patent; one was partially occluded; and three were thrombosed at retrieval. One week after implantation, the prostheses were surrounded by an external capsule, which was present mainly at the two anastomoses. The external capsule covered the entire graft at 3 months. No kinking of the grafts was observed and the presence of a mild yellow stain related to bilirubin uptake was detected at 2 weeks, 1, 3, and 6 months. Histological studies have revealed the formation of a thin internal capsule at both anastomoses, 2 weeks postimplantation, which was not anchored to the graft wall. In the medium-term group, the thrombosed grafts failed to develop an internal capsule, whereas the patent graft exhibited a thick internal capsule made of neocollagenous tissue over the entire graft. This new microporous polyurethane prosthesis did not perform satisfactorily as an infra-renal substitute in dogs and its in vivo stability requires further assessment. Thus, the concept of a polyurethane with closed pores does not achieve what was anticipated.

  1. 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.

  2. 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

    National Research Council Canada - National Science Library

    Bachrach, Nathaniel

    2003-01-01

    .... This past year the source of he defects was determined to be the freeze-drying process. Ongoing efforts toward process optimization and design modifications that will provide undamaged tissue grafts are presented in this report...

  3. Outcome after VAC® therapy for infected bypass grafts in the lower limb.

    Science.gov (United States)

    Acosta, S; Monsen, C

    2012-09-01

    To assess the outcome of vacuum-assisted wound closure (VAC(®)) therapy for infected bypass grafts. A retrospective 7-year review of patient records from 2004 to 2011 of all patients receiving VAC(®) therapy for infected bypass grafts. Thirty-seven patients with 42 wounds and 45 infected bypass (28 synthetic) grafts received VAC(®) treatment. Two serious bleeding episodes from the suture lines occurred. The median VAC(®) therapy time was 20 days. The proportion of patent bypass grafts was 91% (41/45) at a median time of 3.5 months from the start of VAC(®) therapy. Five patients with seven bypasses had persistent infection or re-infection, and the total graft preservation rate was 76% (34/45). The median follow-up time was 15 months. The presence of two infected bypass grafts in one groin wound was associated with an increased major amputation rate (hazard ratio (HR) 7.4 [95% confidence interval (CI) 2.0-27.5]), and synthetic graft infection (HR 5.0 [95% CI 1.5-17.4]) and non-healed wound (HR 3.6 [95% CI 1.5-8.7]) were associated with mortality. VAC(®) therapy of infected bypass grafts was able to induce effective wound healing without compromising the early bypass function. Two infected synthetic bypasses in the wound were associated with the highest risk of adverse outcome. Copyright © 2012 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  4. 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

  5. Enhanced Pulmonary Vascular and Alveolar Development via Prenatal Administration of a Slow-Release Synthetic Prostacyclin Agonist in Rat Fetal Lung Hypoplasia

    Science.gov (United States)

    Umeda, Satoshi; Miyagawa, Shigeru; Fukushima, Satsuki; Oda, Noriko; Saito, Atsuhiro; Sakai, Yoshiki; Sawa, Yoshiki; Okuyama, Hiroomi

    2016-01-01

    Lung hypoplasia and pulmonary hypertension are the major causes of mortality in neonates with congenital diaphragmatic hernia (CDH). Although the prostaglandin pathway plays a pivotal role in lung development, the reported efficacy of postnatal prostaglandin agonist treatment is suboptimal. We hypothesized that prenatal treatment with ONO-1301SR, a slow-release form of a novel synthetic prostacyclin agonist with thromboxane inhibitory activity, might enhance the development of lungs exhibiting hypoplasia in the fetal period. On embryonic day (E) 9.5, nitrofen was given to pregnant Sprague-Dawley rats to establish a CDH-related lung hypoplasia model, whereas normal rats received the vehicle only. The same day, either ONO-1301SR or a placebo was also randomly administered. On E21.5, the fetuses of the normal group and those exhibiting CDH were analyzed. Prenatal ONO-1301SR administration had no influence on the incidence of nitrofen-induced CDH. The lung-to-body weight ratio in the CDH+ONO group was greater than that in the CDH group. Histologically, the medial wall in the CDH+ONO group was two-thirds thinner than that in the CDH group. In addition, the number of Ttf-1-positive cells and the capillary density were ≥1.5 times greater in the CDH+ONO group than in the CDH group, and this increase was associated with higher expression of vascular endothelial growth factor and stromal cell-derived factor in the CDH+ONO group, suggesting enhanced development of the alveolar and capillary networks. Thus, prenatal ONO-1301SR was protective against the progression of lung hypoplasia associated with CDH in a nitrofen-induced rat model, indicating the potential of this treatment for pathologies exhibiting lung hypoplasia. PMID:27529478

  6. The effects of exendin-4 treatment on graft failure: an animal study using a novel re-vascularized minimal human islet transplant model.

    Directory of Open Access Journals (Sweden)

    Afaf Sahraoui

    Full Text Available Islet transplantation has become a viable clinical treatment, but is still compromised by long-term graft failure. Exendin-4, a glucagon-like peptide 1 receptor agonist, has in clinical studies been shown to improve insulin secretion in islet transplanted patients. However, little is known about the effect of exendin-4 on other metabolic parameters. We therefore aimed to determine what influence exendin-4 would have on revascularized minimal human islet grafts in a state of graft failure in terms of glucose metabolism, body weight, lipid levels and graft survival. Introducing the bilateral, subcapsular islet transplantation model, we first transplanted diabetic mice with a murine graft under the left kidney capsule sufficient to restore normoglycemia. After a convalescent period, we performed a second transplantation under the right kidney capsule with a minimal human islet graft and allowed for a second recovery. We then performed a left-sided nephrectomy, and immediately started treatment with exendin-4 with a low (20μg/kg/day or high (200μg/kg/day dose, or saline subcutaneously twice daily for 15 days. Blood was sampled, blood glucose and body weight monitored. The transplanted human islet grafts were collected at study end point and analyzed. We found that exendin-4 exerts its effect on failing human islet grafts in a bell-shaped dose-response curve. Both doses of exendin-4 equally and significantly reduced blood glucose. Glucagon-like peptide 1 (GLP-1, C-peptide and pro-insulin were conversely increased. In the course of the treatment, body weight and cholesterol levels were not affected. However, immunohistochemistry revealed an increase in beta cell nuclei count and reduced TUNEL staining only in the group treated with a low dose of exendin-4 compared to the high dose and control. Collectively, these results suggest that exendin-4 has a potential rescue effect on failing, revascularized human islets in terms of lowering blood glucose

  7. Particle size of bone graft and method of impaction affect initial stability of cemented cups: human cadaveric and synthetic pelvic specimen studies.

    NARCIS (Netherlands)

    Bolder, S.B.T.; Schreurs, B.W.; Verdonschot, N.J.J.; Unen, J. van; Gardeniers, J.W.M.; Slooff, T.J.J.H.

    2003-01-01

    We determined the effect of bone graft particle size and impaction technique on the initial stability of cemented acetabular cups. First, acetabular reconstructions were performed in human cadaveric pelvic bones in which type 2 AAOS cavitary defects were created. Reconstructions were made with small

  8. Vascular ultrasound.

    Science.gov (United States)

    Pilcher, D B; Ricci, M A

    1998-04-01

    Surgeon-interpreted diagnostic ultrasound has become the preferred screening test and often the definitive test for the diagnosis of arterial stenosis, aneurysm, and venous thrombosis. As a modality for surveillance, its noninvasive quality makes it particularly appealing as the test of choice to screen patients for abdominal aortic aneurysms or to perform follow-up examinations on those patients with a carotid endartectomy or in situ bypass grafts. The increasing reliance on intraoperative duplex imaging of vascular procedures demands that the surgeon learn the skills to perform the studies without a technologist or radiologist to interpret the examination.

  9. A heparin-bonded vascular graft generates no systemic effect on markers of hemostasis activation or detectable heparin-induced thrombocytopeniaassociated antibodies in humans

    NARCIS (Netherlands)

    Heyligers, Jan M. M.; Lisman, Ton; Verhagen, Hence J. M.; Weeterings, Cees; de Groot, Philip G.; Moll, Frans L.

    Objectives. Almost a third of patients who undergo peripheral bypass procedures do not have suitable veins, making the use of prosthetic materials necessary. Prosthetic materials can cause platelet adhesion and activation of the coagulation cascade on the graft. One potential strategy to reduce this

  10. Medial support by fibula bone graft in angular stable plate fixation of proximal humeral fractures: an in vitro study with synthetic bone.

    Science.gov (United States)

    Osterhoff, Georg; Baumgartner, Daniel; Favre, Philippe; Wanner, Guido A; Gerber, Hans; Simmen, Hans-Peter; Werner, Clément M L

    2011-07-01

    Failure to achieve stable fixation with medial support in proximal humeral fractures can result in varus malalignment and cut-through of the proximal screws. The purpose of this study was to investigate the influence of an intramedullary fibula bone graft on the biomechanical properties of proximal humeral fractures stabilized by angular stable plate fixation in a bone model under cyclic loading. Two fixation techniques were tested in 20 composite analog humeri models. In group F- (n = 10), fractures were fixed by an anatomically formed locking plate system. In group F+ (n = 10), the same fixation system was used with an additional fibular graft model with a length of 6 cm inserted in an intramedullary manner. Active abduction was simulated for 400 cycles by use of a recently established testing setup. Fragment gap distance was measured, and thereby, intercyclic motion, fragment migration, and residual plastic deformation were determined. The addition of a fibular graft to the fixation plate led to 5 times lower intercyclic motion, 2 times lower fragment migration, and 2 times less residual plastic deformation. Neither screw pullout, cut-through, nor implant failure was observed. Medial support with an intramedullary fibular graft in an angular stable fixation of the proximal humerus in vitro increases overall stiffness of the bone-implant construct and reduces migration of the humeral head fragment. This technique might provide a useful tool in the treatment of displaced proximal humeral fractures, especially when there is medial comminution. Copyright © 2011 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  11. One-stage reconstruction of isolated and combined tendon defects with the vascularized adductor magnus tendon graft: Surgical technique and preliminary results.

    Science.gov (United States)

    Neuwirth, M; Bürger, H; Palle, W; Rab, M

    2016-07-01

    Secondary reconstructions of isolated and combined tendon defects are still a challenge for plastic surgeons. Due to its reliable anatomy, reconstructive potential and low donor-site morbidity, the medial femoral condyle is an ideal area for harvesting isolated and combined tendon flaps. This study evaluates our preliminary results with the vascularized adductor magnus tendon flap. The study included six patients who received a vascularized tendon flap (upper extremity: three patients; lower extremity: three patients) from 2011 to 2015. For three patients, the adductor magnus tendon was used as a single flap; for the other three patients, the tendon was included in a composite flap. A retrospective chart review provided the patients' demographic data, surgical details and the post-operative course. The further objective and patient-reported outcome was evaluated with a long-term follow-up. All of the free vascularized flaps healed without complications and with good vascularization upon duplex ultrasonography. One patient did, however, require revision surgery in the late post-operative course. At the end point, all patients showed good functional results without any donor-site morbidity. For carefully selected isolated and combined tendon defects on the upper and lower extremities, the vascularized adductor magnus tendon flap provides a reliable and versatile method for microsurgical reconstruction. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  12. 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.

  13. Biochemical changes on the repair of surgical bone defects grafted with biphasic synthetic micro-granular HA + β-tricalcium phosphate induced by laser and LED phototherapies assessed by Raman spectroscopy

    Science.gov (United States)

    Pinheiro, Antonio Luiz B.; Soares, Luiz Guilherme P.; Marques, Aparecida Maria C.; Silveira, Landulfo

    2016-03-01

    This work aimed the assessment of the biochemical changes during bone mineralization induced by laser and LED irradiation in an animal model of bone repair using a spectral model based on Raman spectroscopy. Six groups were studied: Clot, Laser (λ780 nm, 70 mW), LED (λ850 nm +/- 10 nm, 150 mW), Biomaterial (biphasic synthetic microgranular hydroxyapatite (HA) + β-tricalcium phosphate), Laser + Biomaterial and LED + Biomaterial. When indicated, defects were further irradiated at 48 h interval during 2 wks, 20 J/cm2 per session. At 15th and 30th days, femurs were dissected and spectra of the defects were collected. Raman spectra were submitted to a model to estimate the relative amount of collagen, phosphate HA and carbonate HA, by using spectra of pure collagen, biomaterial and basal bone, respectively. At 15th days, the use of biomaterial associated to phototherapy reduced the collagen formation, whereas the amount of carbonate HA was not different in all groups. The phosphate HA was higher in the groups that received biomaterial grafts. At 30th days, it was observed an increase of collagen for the group Laser + Biomaterial, and a reduction in the carbonate HA for the LED + Biomaterial. The phosphate HA was higher for the groups LED + Biomaterial and Laser + Biomaterial, while decreased for the group Biomaterial. These results indicated that the use of Laser and LED phototherapies improved the repair of bone defects grafted with the biomaterial by increasing the collagen deposition and phosphate HA.

  14. The outcome and complications of the DiaTAP bioCarbon button-graft vascular access device in haemodialysis patients: a two-year experience.

    Science.gov (United States)

    Paul, M D; Parfrey, P; Marshall, D; Aldrete, V; Purchase, L; Gault, H

    1986-01-01

    The outcome and complications which developed in 8 hemodialysis patients who received 12 DiaTAP bioCarbon button vascular-access devices were reviewed. All patients had a poor vascular access history. Three of twelve devices have been replaced because of thrombosis and two because of infection. Four patients have had 10 episodes of reduced blood flow. Streptokinase infusion into the DiaTAP button led to improved blood flow in 8 of 10 episodes. The 6-month survival rate of the DiaTAP access device was 67% and the average functioning life was 9.4 months. It was a valuable form of access when others had failed.

  15. 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...

  16. Lower Extremity Permanent Dialysis Vascular Access.

    Science.gov (United States)

    Parekh, Vishal B; Niyyar, Vandana D; Vachharajani, Tushar J

    2016-09-07

    Hemodialysis remains the most commonly used RRT option around the world. Technological advances, superior access to care, and better quality of care have led to overall improvement in survival of patients on long-term hemodialysis. Maintaining a functioning upper extremity vascular access for a prolonged duration continues to remain a challenge for dialysis providers. Frequently encountered difficulties in clinical practice include (1) a high incidence of central venous catheter-related central vein stenosis and (2) limited options for creating a functioning upper extremity permanent arteriovenous access. Lack of surgical skills, fear of complications, and limited involvement of the treating nephrologists in the decision-making process are some of the reasons why lower extremity permanent dialysis access remains an infrequently used option. Similar to upper extremity vascular access options, lower extremity arteriovenous fistula remains a preferred access over arteriovenous synthetic graft. The use of femoral tunneled catheter as a long-term access should be avoided as far as possible, especially with the availability of newer graft-catheter hybrid devices. Our review provides a summary of clinical evidence published in surgical, radiology, and nephrology literature highlighting the pros and cons of different types of lower extremity permanent dialysis access. Copyright © 2016 by the American Society of Nephrology.

  17. Plant grafting: new mechanisms, evolutionary implications.

    Science.gov (United States)

    Goldschmidt, Eliezer E

    2014-01-01

    Grafting, an old plant propagation practice, is still widely used with fruit trees and in recent decades also with vegetables. Taxonomic proximity is a general prerequisite for successful graft-take and long-term survival of the grafted, composite plant. However, the mechanisms underlying interspecific graft incompatibility are as yet insufficiently understood. Hormonal signals, auxin in particular, are believed to play an important role in the wound healing and vascular regeneration within the graft union zone. Incomplete and convoluted vascular connections impede the vital upward and downward whole plant transfer routes. Long-distance protein, mRNA and small RNA graft-transmissible signals currently emerge as novel mechanisms which regulate nutritional and developmental root/top relations and may play a pivotal role in grafting physiology. Grafting also has significant pathogenic projections. On one hand, stock to scion mechanical contact enables the spread of diseases, even without a complete graft union. But, on the other hand, grafting onto resistant rootstocks serves as a principal tool in the management of fruit tree plagues and vegetable soil-borne diseases. The 'graft hybrid' historic controversy has not yet been resolved. Recent evidence suggests that epigenetic modification of DNA-methylation patterns may account for certain graft-transformation phenomena. Root grafting is a wide spread natural phenomenon; both intraspecific and interspecific root grafts have been recorded. Root grafts have an evolutionary role in the survival of storm-hit forest stands as well as in the spread of devastating diseases. A more fundamental evolutionary role is hinted by recent findings that demonstrate plastid and nuclear genome transfer between distinct Nicotiana species in the graft union zone, within a tissue culture system. This has led to the formation of alloploid cells that, under laboratory conditions, gave rise to a novel, alloploid Nicotiana species, indicating

  18. A comparative clinico-radiographic study of guided tissue regeneration with bioresorbable membrane and a composite synthetic bone graft for the treatment of periodontal osseous defects

    Directory of Open Access Journals (Sweden)

    Sumedha Srivastava

    2015-01-01

    Full Text Available Aim: The aim was to evaluate the bonefill in periodontal osseous defects with the help of guided tissue regeneration, bioresorbable membrane (PerioCol + bone graft (Grabio Glascera in combination and with bonegraft (Grabio Glascera alone. Materials and Methods: The study involved total 30 sites in systemically healthy 19 patients. The parameters for evaluation includes plaque index sulcus bleeding index with one or more periodontal osseous defects having (i probing depth (PD of ≥ 5 mm (ii clinical attachment loss (CAL of ≥ 5 mm and (iii ≥3 mm of radiographic periodontal osseous defect (iv bonefill (v crestal bone loss (vi defect resolution. The study involved the three wall and two wall defects which should be either located interproximally or involving the furcation area. The statistical analysis was done using Statistical Package for Social Sciences, the Wilcoxon signed rank statistic W + for Mann-Whitney U-test. Results: The net gain in PD and CAL after 6 months for Group I ([PerioCol] + [Grabio Glascera] and Group II (Grabio Glascera was 3.94 ± 1.81 mm, 3.57 ± 2.21 mm and 3.94 ± 1.81, 3.57 ± 2.21 mm, respectively. The results of the study for Group I and Group II with regards to mean net bonefill, was 3.25 ± 2.32 (58% mm and 5.14 ± 3.84 (40.26 ± 19.14% mm, crestal bone loss − 0.25 ± 0.68 mm and − 0.79 ± 1.19 mm. Defect resolution 3.50 ± 2.34 mm and 5.93 ± 4.01 mm, respectively. Conclusion: On comparing both the groups together after 6 months of therapy, the results were equally effective for combination of graft and membrane versus bone graft alone since no statistical significant difference was seen between above parameters for both the groups. Thus, both the treatment modalities are comparable and equally effective.

  19. Reconstruction of Traumatic External Iliac Artery Dissection Due to Vascular Clamping.

    Science.gov (United States)

    Kırnap, Mahir; Özçelik, Ümit; Akdur, Aydıncan; Ayvazoğlu Soy, Ebru H; Işıklar, İclal; Yarbuğ Karakayalı, Feza; Moray, Gökhan; Haberal, Mehmet

    2017-10-31

    Traumatic external iliac artery dissection after renal transplant is a rare complication, but it should be urgently managed due to its devastating effects on graft and lower limb circulation. External iliac artery dissection is seen more in recipients with diabetes mellitus and comorbid disease. Recipients with external iliac artery dissection should be treated immediately by percutaneus angioplasty or surgical reconstruction. In this study, we reported the management of 2 kidney transplant cases with external iliac artery dissection due to vascular clamping of the artery. External iliac artery dissection was diagnosed by ultrasonography in both cases. After failed percutaneous interventional angioplasty, we reconstructed the external iliac artery dissection surgically and replaced the external iliac artery with polytetra-fluoroethylene grafts in both patients. Both patients were discharged with normal functioning grafts showing 0.9 and 0.8 mg/dL serum creatinine levels at month 3 posttransplant. Close monitoring of recipients after transplant is mandatory for early diagnosis and early management of external iliac artery dissection to prevent graft loss and preserve lower limb circulation. Routine Doppler ultrasonography is an inexpensive and useful tool for early diagnosis in cases of sudden cessation or decrease in urine. In cases of failed percutaneous interventional angioplasty, reconstruction with synthetic vascular grafts can be safely applied in external iliac artery dissection.

  20. Graft infections after surgical aortic reconstructions

    OpenAIRE

    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 surgical reconstructions as first line of treatment for aorto-iliac diseases. Nowadays, open reconstructions are primarily reserved for patients unsuitable for endovascular reconstructions or for redo ...

  1. Clinical trial and in-vitro study comparing the efficacy of treating bony lesions with allografts versus synthetic or highly-processed xenogeneic bone grafts

    DEFF Research Database (Denmark)

    Kubosch, Eva Johanna; Bernstein, Anke; Wolf, Laura

    2016-01-01

    BACKGROUND: Our study aim was to compare allogeneic cancellous bone (ACB) and synthetic or highly-processed xenogeneic bone substitutes (SBS) in the treatment of skeletal defects in orthopedic surgery. METHODS: 232 patients treated for bony lesions with ACB (n = 116) or SBS (n = 116) within a 10......-year time period were included in this case-control study. Furthermore, both materials were seeded with human osteoblasts (hOB, n = 10) and analyzed by histology, for viability (AlamarBlue®) and protein expression activity (Luminex®). RESULTS: The complication rate was 14.2 %, proportion of defects....... Histological examination revealed similar bone structures, whereas cell remnants were apparent only in the allografts. Both materials were biocompatible in-vitro, and seeded with human osteoblasts. The cells remained vital over the 3-week culture period and produced microscopically typical bone matrix. We...

  2. Development of a one-step approach for the reconstruction of full thickness skin defects using minced split thickness skin grafts and biodegradable synthetic scaffolds as a dermal substitute.

    Science.gov (United States)

    Sharma, Kavita; Bullock, Anthony; Ralston, David; MacNeil, Sheila

    2014-08-01

    Tissue engineering has progressed in delivering laboratory-expanded keratinocytes to the clinic; however the production of a suitable alternative to a skin graft, containing both epidermis and dermis still remains a challenge. To develop a one-step approach to wound reconstruction using finely minced split thickness skin and a biodegradable synthetic dermal substitute. This was explored in vitro using scalpel diced pieces of split thickness human skin combined with synthetic electrospun polylactide (PLA) scaffolds. To aid the spreading of tissue, 1% methylcellulose was used and platelet releasate was examined for its effect on cellular outgrowth from tissue explants. The outcome parameters included the metabolic activity of the migrating cells and their ability to produce collagen. Cell presence and migration on the scaffolds were assessed using fluorescence microscopy and SEM. Cells were identified as keratinocytes by immunostaining for pan-cytokeratin. Collagen deposition was quantified by using Sirius red. Skin cells migrated along the fibers of the scaffold and formed new collagen. 1% methylcellulose improved the tissue handling properties of the minced skin. Platelet releasate did not stimulate the migration of skin cells along scaffold fibers. Immunohistochemistry and SEM confirmed the presence of both epithelial and stromal cells in the new tissue. We describe the first key steps in the production of a skin substitute to be assembled in theatre eliminating the need for cell culture. Whilst further experiments are needed to develop this technique it can be a useful addition to armamentarium of the reconstructive surgeon. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

  3. Non-Vascularised Fibular Grafting After Resection of Distal Femoral ...

    African Journals Online (AJOL)

    Background: Vascularized fibular grafting, allografting, megaprosthesis and allograft-prosthesis composite are suitable limb salvage techniques after resection of ... the initial observation showed such a wide non-vascularized fibular grafting for arthrodesis of the knee after resection of the distal femoral tumours is a feasible ...

  4. 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

    2018-03-01

    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.

  5. Plant grafting: new mechanisms, evolutionary implications

    Directory of Open Access Journals (Sweden)

    Eliezer E Goldschmidt

    2014-12-01

    Full Text Available Grafting, an old plant propagation practice, is still widely used with fruit trees and in recent decades also with vegetables. Taxonomic proximity is a general prerequisite for successful graft-take and long-term survival of the grafted, composite plant. However, the mechanisms underlying interspecific graft incompatibility are as yet insufficiently understood. Hormonal signals, auxin in particular, are believed to play an important role in the wound healing and vascular regeneration within the graft union zone. Long-distance protein, mRNA and small RNA graft-transmissible signals currently emerge as novel mechanisms which regulate nutritional and developmental root/top relations and may play a pivotal role in grafting physiology. Grafting also has significant pathogenic projections. On one hand, stock to scion mechanical contact enables the spread of diseases, even without a complete graft union. But, on the other hand, grafting onto resistant rootstocks serves as a principal tool in the management of fruit tree plagues and vegetable soil-borne diseases. The ‘graft hybrid’ historic controversy has not yet been resolved. Recent evidence suggests that epigenetic modification of DNA-methylation patterns may account for certain graft-transformation phenomena. Root grafting is a wide spread natural phenomenon; both intraspecific and interspecific root grafts have been recorded. Root grafts have an evolutionary role in the survival of storm-hit forest stands as well as in the spread of devastating diseases. A more fundamental evolutionary role is hinted by recent findings that demonstrate plastid and nuclear genome transfer between distinct Nicotiana species in the graft union zone, within a tissue culture system. This has led to the formation of alloploid cells that, under laboratory conditions, gave rise to a novel, alloploid Nicotiana species, indicating that natural grafts may play a role in plant speciation. under certain circumstances.

  6. 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.

  7. Diagnosis and Treatment of Vascular Surgery Related Infection

    OpenAIRE

    Zhang, Yong-Gan; Guo, Xue-Li; Song, Yan; Miao, Chao-Feng; Zhang, Chuang; Chen, Ning-Heng

    2015-01-01

    Surgical site infection (SSI) is an important component of infections acquired from hospital. The most significant feature of vascular surgery different from other surgeries is frequent application of artificial grafts. Once SSI occurs after vascular operations with grafts, it might results in a serious disaster. Staphylococcus aureus and coagulase-negative Staphylococcus are the most common pathogenic bacteria for SSI after vascular surgery. Although SSI in vascular surgery often lacks of ty...

  8. 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

  9. Complexes of silver(I) ions and silver phosphate nanoparticles with hyaluronic acid and/or chitosan as promising antimicrobial agents for vascular grafts.

    Science.gov (United States)

    Chudobova, Dagmar; Nejdl, Lukas; Gumulec, Jaromir; Krystofova, Olga; Rodrigo, Miguel Angel Merlos; Kynicky, Jindrich; Ruttkay-Nedecky, Branislav; Kopel, Pavel; Babula, Petr; Adam, Vojtech; Kizek, Rene

    2013-06-28

    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 investigated complexes.

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

    Science.gov (United States)

    Chudobova, Dagmar; Nejdl, Lukas; Gumulec, Jaromir; Krystofova, Olga; Rodrigo, Miguel Angel Merlos; Kynicky, Jindrich; Ruttkay-Nedecky, Branislav; Kopel, Pavel; Babula, Petr; Adam, Vojtech; Kizek, Rene

    2013-01-01

    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 investigated complexes

  11. Assessment of the accumulation of technetium-99m labelled leukocytes in the treatment of the infections of vascular prosthesis

    International Nuclear Information System (INIS)

    Pupka, A.; Kaluza, G.; Skora, J.; Szyber, P.; Rynowiecka, M.

    2003-01-01

    The purpose of this is to evaluate the accumulation of technetium-99m-labelled leukocytes after change of vascular, dacron and infected prosthetic graft in arterial homo grafts harvested from multiorgan-procurement - with own computer program. In this paper 11 cases of aorto-ilio-femoral graft infection treated by the replacement of infected prosthesis with fresh, bifurcated, arterial homografts is presented. In all patients clinical investigations revealed vascular prosthesis infection with the rupture of vascular anastomoses between the prosthesis' branch and wall of artery that resulted with hemorrhage. The Duplex- Doppler ultrasound and the scintigraphy with use of technetium-labeled leucocytes were used in the diagnostic trial of infection and of the healing process of the arterial homografts.The area of the accumulation of 99m Tc labelled leukocytes was evaluated with own computer programs. Positive clinical effect was obtained in all patients.The regression of infection after in situ replacement of the synthetic prosthesis with homograft was presented with the scintigraphic examination: in these patients the area of leukocytes accumulation decreased from 34±3 cm 2 to 9±2cm 2 . The use of scintigraphy with 99m Tc labelled leukocytes to evaluate the healing process of the arterial homografts in therapy of the prosthetic graft is a the accumulation of leucocytes is facilitation in the monitoring of regression of infection. (author)

  12. In-depth evaluation of commercially available human vascular smooth muscle cells phenotype: Implications for vascular tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Timraz, Sara B.H., E-mail: sara.timraz@kustar.ac.ae [Department of Biomedical Engineering, Khalifa University, PO Box 127788, Abu Dhabi (United Arab Emirates); Farhat, Ilyas A.H., E-mail: ilyas.farhat@outlook.com [Department of Applied Mathematics and Sciences, Khalifa University, PO Box 127788, Abu Dhabi (United Arab Emirates); Alhussein, Ghada, E-mail: ghada.alhussein@kustar.ac.ae [Department of Biomedical Engineering, Khalifa University, PO Box 127788, Abu Dhabi (United Arab Emirates); Christoforou, Nicolas, E-mail: nicolas.christoforou@kustar.ac.ae [Department of Biomedical Engineering, Khalifa University, PO Box 127788, Abu Dhabi (United Arab Emirates); Department of Biomedical Engineering, Duke University, Durham, NC 27708 (United States); Teo, Jeremy C.M., E-mail: jeremy.teo@kustar.ac.ae [Department of Biomedical Engineering, Khalifa University, PO Box 127788, Abu Dhabi (United Arab Emirates)

    2016-05-01

    In vitro research on vascular tissue engineering has extensively used isolated primary human or animal smooth muscle cells (SMC). Research programs that lack such facilities tend towards commercially available primary cells sources. Here, we aim to evaluate the capacity of commercially available human SMC to maintain their contractile phenotype, and determine if dedifferentiation towards the synthetic phenotype occurs in response to conventional cell culture and passaging without any external biochemical or mechanical stimuli. Lower passage SMC adopted a contractile phenotype marked by a relatively slower proliferation rate, higher expression of proteins of the contractile apparatus and smoothelin, elongated morphology, and reduced deposition of collagen types I and III. As the passage number increased, migratory capacity was enhanced, average cell speed, total distance and net distance travelled increased up to passage 8. Through the various assays, corroborative evidence pinpoints SMC at passage 7 as the transition point between the contractile and synthetic phenotypes, while passage 8 distinctly and consistently exhibited characteristics of synthetic phenotype. This knowledge is particularly useful in selecting SMC of appropriate passage number for the target vascular tissue engineering application, for example, a homeostatic vascular graft for blood vessel replacement versus recreating atherosclerotic blood vessel model in vitro. - Highlights: • Ability of human smooth muscle cells to alter phenotype in culture is evaluated. • Examined the effect of passaging human smooth muscle cells on phenotype. • Phenotype is assessed based on morphology, proliferation, markers, and migration. • Multi-resolution assessment methodology, single-cell and cell-population. • Lower and higher passages than P7 adopted a contractile and synthetic phenotype respectively.

  13. Bypass materials in vascular surgery

    Directory of Open Access Journals (Sweden)

    Willich, Stephan N.

    2006-03-01

    (DIMDI, as well as by a manual search. The for-mer included the following electronic resources: SOMED (SM78, Cochrane Library - Central (CCTR93, MEDLINE Alert (ME0A, MEDLINE (ME95, CATFILEplus (CATLINE (CA66, ETHMED (ED93, GeroLit (GE79, HECLINET (HN69, AMED (CB85, CAB Abstracts (CV72, GLOBAL Health (AZ72, IPA (IA70, El-sevier BIOBASE (EB94, BIOSIS Previews (BA93, EMBASE (EM95, EMBASE Alert (EA08, SciSearch (IS90, Cochrane Library - CDSR (CDSR93, NHS-CRD-DARE (CDAR94, NHS-CRD-HTA (INAHTA, and NHS-EED (NHSEED. The present report included German and English literature published between the years 1999 and 2004. A list of the search parameters can be found in the appendix. No limits were placed on the target population, and the methodical quality of the included studies was determined using standardised checklists. Results: The studies included in this health technology assessment compared the following bypass materials: autologous vein, human umbilical vein (HUV and synthetic materials such as PTFE or Dacron®. Both the systematic reviews and the randomised controlled trials comparing autologous vein grafts to other bypass materials come to the conclusion that autologous vein is superior to all other materials. From a medical viewpoint, there are no clear differences between the various synthetic materials.To date, the subject of bypass materials in vascular surgery has not been addressed comprehensively from an economic point of view. Indeed, we were able to identify only one publication that compared the cost of various bypass materials. The remaining health economic studies did not compare costs, cost effectiveness, or quality of life associated with the use of various bypass materials. Discussion: When deciding which bypass material to use, vascular surgeons take a number of medical considerations into account, including the bypass area, the availability of autologous vein, the amount of operation time available, and the health status of the patient. The studies

  14. 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.

  15. Multifaceted prospects of nanocomposites for cardiovascular grafts and stents

    Directory of Open Access Journals (Sweden)

    Vellayappan MV

    2015-04-01

    Full Text Available Muthu Vignesh Vellayappan,1 Arunpandian Balaji,1 Aruna Priyadarshini Subramanian,1 Agnes Aruna John,1 Saravana Kumar Jaganathan,1 Selvakumar Murugesan,2 Eko Supriyanto,1 Mustafa Yusof1 1IJN-UTM Cardiovascular Engineering Centre, Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Johor Bahru, Malaysia; 2Rubber Technology Center, Indian Institute of Technology, Kharagpur, India Abstract: Cardiovascular disease is the leading cause of death across the globe. The use of synthetic materials is indispensable in the treatment of cardiovascular disease. Major drawbacks related to the use of biomaterials are their mechanical properties and biocompatibility, and these have to be circumvented before promoting the material to the market or clinical setting. Revolutionary advancements in nanotechnology have introduced a novel class of materials called nanocomposites which have superior properties for biomedical applications. Recently, there has been a widespread recognition of the nanocomposites utilizing polyhedral oligomeric silsesquioxane, bacterial cellulose, silk fibroin, iron oxide magnetic nanoparticles, and carbon nanotubes in cardiovascular grafts and stents. The unique characteristics of these nanocomposites have led to the development of a wide range of nanostructured copolymers with appreciably enhanced properties, such as improved mechanical, chemical, and physical characteristics suitable for cardiovascular implants. The incorporation of advanced nanocomposite materials in cardiovascular grafts and stents improves hemocompatibility, enhances antithrombogenicity, improves mechanical and surface properties, and decreases the microbial response to the cardiovascular implants. A thorough attempt is made to summarize the various applications of nanocomposites for cardiovascular graft and stent applications. This review will highlight the recent advances in nanocomposites and also address the need of future research in

  16. Adolescent External Iliac Artery Trauma: Recurrent Aneurysmal Dilatation of an Iliofemoral Saphenous Vein Graft Treated by Stent-Grafting

    International Nuclear Information System (INIS)

    Lenton, James; Davies, John; Homer-Vanniasinkam, S.; McPherson, Simon

    2008-01-01

    An adolescent male sustained a severe penetrating injury to the external iliac artery. Emergency surgical revascularization was with a reversed long saphenous vein interposition graft. The primary graft and the subsequent revision graft both became aneurysmal. The second graft aneurysm was successfully excluded by endovascular stent-grafts with medium-term primary patency. A venous graft was used initially rather than a synthetic graft to reduce the risk of infection and the potential problems from future growth. Aneurysmal dilatation of venous grafts in children and adolescents is a rare but recognized complication. To the best of our knowledge, exclusion of these aneurysms with stent-grafts has not been previously reported in the adolescent population.

  17. 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,

  18. 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

  19. Experimental studies on glycerol preserved vascular allografts

    NARCIS (Netherlands)

    Fahner, P.J.

    2014-01-01

    Autologous vein is the conduit of choice in patients with critical peripheral arterial disease who need a vascular reconstruction. However, autologous vein could be of inferior quality or used in prior surgery. Vascular allograft transplantation is an attractive alternative to prosthetic grafts in

  20. 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

  1. 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...

  2. Graft nephrectomy: The SGPGI experience

    Directory of Open Access Journals (Sweden)

    Nand Kishore Arvind

    2002-01-01

    associated with systemic complications; late graft nephrectomy is technically more demanding with relatively increased risk of vascular and visceral injuries.

  3. Click-coated, heparinized, decellularized vascular grafts.

    Science.gov (United States)

    Dimitrievska, Sashka; Cai, Chao; Weyers, Amanda; Balestrini, Jenna L; Lin, Tylee; Sundaram, Sumati; Hatachi, Go; Spiegel, David A; Kyriakides, Themis R; Miao, Jianjun; Li, Guoyun; Niklason, Laura E; Linhardt, Robert J

    2015-02-01

    A novel method enabling the engineering of a dense and appropriately oriented heparin-containing layer on decellularized aortas has been developed. Amino groups of decellularized aortas were first modified to azido groups using 3-azidobenzoic acid. Azide-clickable dendrons were attached onto the azido groups through "alkyne-azide" click chemistry, affording a tenfold amplification of adhesions sites. Dendron end groups were finally decorated with end-on modified heparin chains. Heparin chains were oriented like heparan sulfate groups on native endothelial cells surface. X-ray photoelectron spectroscopy, nuclear magnetic resonance imaging, mass spectrometry and Fourier transform infrared FTIR spectroscopy were used to characterize the synthesis steps, building the final heparin layered coatings. The continuity of the heparin coating was verified using fluorescent microscopy and histological analysis. The efficacy of heparin linkage was demonstrated with factor Xa anti-thrombogenic assay and platelet adhesion studies. The results suggest that oriented heparin immobilization to decellularized aortas may improve the in vivo blood compatibility of decellularized aortas and vessels. Copyright © 2014 Acta Materialia Inc. All rights reserved.

  4. In Vivo Remodeling of Fibroblast-Derived Vascular Scaffolds Implanted for 6 Months in Rats

    Directory of Open Access Journals (Sweden)

    Maxime Y. Tondreau

    2016-01-01

    Full Text Available There is a clinical need for tissue-engineered small-diameter (<6 mm vascular grafts since clinical applications are halted by the limited suitability of autologous or synthetic grafts. This study uses the self-assembly approach to produce a fibroblast-derived decellularized vascular scaffold (FDVS that can be available off-the-shelf. Briefly, extracellular matrix scaffolds were produced using human dermal fibroblasts sheets rolled around a mandrel, maintained in culture to allow for the formation of cohesive and three-dimensional tubular constructs, and decellularized by immersion in deionized water. The FDVSs were implanted as an aortic interpositional graft in six Sprague-Dawley rats for 6 months. Five out of the six implants were still patent 6 months after the surgery. Histological analysis showed the infiltration of cells on both abluminal and luminal sides, and immunofluorescence analysis suggested the formation of neomedia comprised of smooth muscle cells and lined underneath with an endothelium. Furthermore, to verify the feasibility of producing tissue-engineered blood vessels of clinically relevant length and diameter, scaffolds with a 4.6 mm inner diameter and 17 cm in length were fabricated with success and stored for an extended period of time, while maintaining suitable properties following the storage period. This novel demonstration of the potential of the FDVS could accelerate the clinical availability of tissue-engineered blood vessels and warrants further preclinical studies.

  5. Ca2+/Calmodulin-Dependent Protein Kinase II in Vascular Smooth Muscle.

    Science.gov (United States)

    Saddouk, F Z; Ginnan, R; Singer, H A

    2017-01-01

    Ca 2+ -dependent signaling pathways are central regulators of differentiated vascular smooth muscle (VSM) contractile function. In addition, Ca 2+ signals regulate VSM gene transcription, proliferation, and migration of dedifferentiated or "synthetic" phenotype VSM cells. Synthetic phenotype VSM growth and hyperplasia are hallmarks of pervasive vascular diseases including hypertension, atherosclerosis, postangioplasty/in-stent restenosis, and vein graft failure. The serine/threonine protein kinase Ca 2+ /calmodulin-dependent protein kinase II (CaMKII) is a ubiquitous mediator of intracellular Ca 2+ signals. Its multifunctional nature, structural complexity, diversity of isoforms, and splice variants all characterize this protein kinase and make study of its activity and function challenging. The kinase has unique autoregulatory mechanisms, and emerging studies suggest that it can function to integrate Ca 2+ and reactive oxygen/nitrogen species signaling. Differentiated VSM expresses primarily CaMKIIγ and -δ isoforms. CaMKIIγ isoform expression correlates closely with the differentiated phenotype, and some studies link its function to regulation of contractile activity and Ca 2+ homeostasis. Conversely, synthetic phenotype VSM cells primarily express CaMKIIδ and substantial evidence links it to regulation of gene transcription, proliferation, and migration of VSM in vitro, and vascular hypertrophic and hyperplastic remodeling in vivo. CaMKIIδ and -γ isoforms have opposing functions at the level of cell cycle regulation, proliferation, and VSM hyperplasia in vivo. Isoform switching following vascular injury is a key step in promoting vascular remodeling. Recent availability of genetically engineered mice with smooth muscle deletion of specific isoforms and transgenics expressing an endogenous inhibitor protein (CAMK2N) has enabled a better understanding of CaMKII function in VSM and should facilitate future studies. © 2017 Elsevier Inc. All rights reserved.

  6. Antioxidants and vascular health.

    Science.gov (United States)

    Bielli, Alessandra; Scioli, Maria Giovanna; Mazzaglia, Donatella; Doldo, Elena; Orlandi, Augusto

    2015-12-15

    Oxygen free radicals and other reactive oxygen species (ROS) are common products of normal aerobic cellular metabolism, but high levels of ROS lead to oxidative stress and cellular damage. Increased production of ROS favors vascular dysfunction, inducing altered vascular permeability and inflammation, accompanied by the loss of vascular modulatory function, the imbalance between vasorelaxation and vasoconstriction, and the aberrant expression of inflammatory adhesion molecules. Inflammatory stimuli promote oxidative stress generated from the increased activity of mitochondrial nicotinamide adenine dinucleotide phosphate oxidase, particularly of the Nox4 isoform, with the consequent impairment of mitochondrial β-oxidation. Vascular dysfunction due to the increase in Nox4 activity and ROS overproduction leads to the progression of cardiovascular diseases, diabetes, inflammatory bowel disease, and neurological disorders. Considerable research into the development of effective antioxidant therapies using natural derivatives or new synthetic molecules has been conducted. Antioxidants may prevent cellular damage by reducing ROS overproduction or interfering in reactions that involve ROS. Vitamin E and ascorbic acid are well known as natural antioxidants that counteract lipid peroxidative damage by scavenging oxygen-derived free radicals, thus restoring vascular function. Recently, preliminary studies on natural antioxidants such as goji berries, thymus, rosemary, green tea ginseng, and garlic have been conducted for their efficacy in preventing vascular damage. N-acetyl-cysteine and propionyl-L-carnitine are synthetic compounds that regulate ROS production by replacing endogenous antioxidants in both endothelial and smooth muscle cells. In this review, we consider the molecular mechanisms underlying the generation of oxidative stress-induced vascular dysfunction as well as the beneficial effects of antioxidant therapies.

  7. 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.

  8. 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.

  9. Computerized tomographic evaluation of aortic prosthetic graft complications

    International Nuclear Information System (INIS)

    Kay, D.; Kalmar, J.A.

    1985-01-01

    Computerized tomography has been found to be an accurate and sensitive method of diagnosing complications of synthetic aortic grafts. Complications in this series of four cases included aortoesophageal fistula, aortoduodenal fistula, pseudoaneurysm, and retroperitoneal hematoma. 6 references, 5 figures

  10. Cadherins in vascular smooth muscle cell (patho)biology: Quid nos scimus?

    Science.gov (United States)

    Frismantiene, Agne; Philippova, Maria; Erne, Paul; Resink, Therese J

    2018-05-01

    Vascular smooth muscle cells (SMCs) phenotypes span a reversible continuum from quiescent/contractile (differentiated) to proliferative/synthetic (dedifferentiated) enabling them to perform a diversity of functions that are context-dependent and important for vascular tone-diameter homeostasis, vasculogenesis, angiogenesis or vessel reparation after injury. Dysregulated phenotype modulation and failure to maintain/regain the mature differentiated and contractile phenotypic state is pivotal in the development of vascular diseases such as atherosclerosis and restenosis after angioplasty and coronary bypass grafting. Many functions of SMCs such as adhesion, migration, proliferation, contraction, differentiation and apoptosis are regulated by a broad spectrum of cell-cell and cell-matrix adhesion molecules. Cadherins represent a superfamily of cell surface homophilic adhesion molecules with fundamental roles in morphogenetic and differentiation processes during development and in the maintenance of tissue integrity and homeostasis in adults. The cadherins have major inputs on signalling pathways and cytoskeletal assemblies that participate in regulating processes such as cell polarity, migration, proliferation, survival, phenotype and differentiation. Abnormalities in these processes have long been recognized to underlie pathological SMC-driven reparation, but knowledge on the involvement of cadherins is remarkably limited. This article presents a comprehensive review of cadherin family members currently identified on vascular SMCs in relation to their functions, molecular mechanisms of action and relevance for vascular pathology. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Recent progress on the design and applications of polysaccharide-based graft copolymer hydrogels as adsorbents for wastewater purification

    CSIR Research Space (South Africa)

    Mittal, Hemant

    2016-05-01

    Full Text Available as emulsifiers and thickeners. In their natural form, gum polysaccharides have poor mechanical and physical properties; therefore, they are frequently modified with various synthetic monomers such as acrylamide and acrylic acid using graft copolymerization. Graft...

  12. Vascular Cures

    Science.gov (United States)

    ... vascular disease, such as stroke, aneurysm and pulmonary artery disease. Each one has their own unique story about their battle with vascular disease and their road to recovery. SEE PATIENT STORIES Our Supporters Caring ...

  13. Hydrophilicity, Viscoelastic, and Physicochemical Properties Variations in Dental Bone Grafting Substitutes.

    Science.gov (United States)

    Trajkovski, Branko; Jaunich, Matthias; Müller, Wolf-Dieter; Beuer, Florian; Zafiropoulos, Gregory-George; Houshmand, Alireza

    2018-01-30

    The indication-oriented Dental Bone Graft Substitutes (DBGS) selection, the correct bone defects classification, and appropriate treatment planning are very crucial for obtaining successful clinical results. However, hydrophilic, viscoelastic, and physicochemical properties' influence on the DBGS regenerative potential has poorly been studied. For that reason, we investigated the dimensional changes and molecular mobility by Dynamic Mechanical Analysis (DMA) of xenograft (cerabone ® ), synthetic (maxresorb ® ), and allograft (maxgraft ® , Puros ® ) blocks in a wet and dry state. While no significant differences could be seen in dry state, cerabone ® and maxresorb ® blocks showed a slight height decrease in wet state, whereas both maxgraft ® and Puros ® had an almost identical height increase. In addition, cerabone ® and maxresorb ® blocks remained highly rigid and their damping behaviour was not influenced by the water. On the other hand, both maxgraft ® and Puros ® had a strong increase in their molecular mobility with different damping behaviour profiles during the wet state. A high-speed microscopical imaging system was used to analyze the hydrophilicity in several naturally derived (cerabone ® , Bio-Oss ® , NuOss ® , SIC ® nature graft) and synthetic DBGS granules (maxresorb ® , BoneCeramic ® , NanoBone ® , Ceros ® ). The highest level of hydrophilicity was detected in cerabone ® and maxresorb ® , while Bio-Oss ® and BoneCeramic ® had the lowest level of hydrophilicity among both naturally derived and synthetic DBGS groups. Deviations among the DBGS were also addressed via physicochemical differences recorded by Micro Computed Tomography, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, X-ray powder Diffractometry, and Thermogravimetric Analysis. Such DBGS variations could influence the volume stability at the grafting site, handling as well as the speed of vascularization and bone regeneration. Therefore, this

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

    Science.gov (United States)

    Roll, Stephanie; Müller-Nordhorn, Jacqueline; Keil, Thomas; Scholz, Hans; Eidt, Daniela; Greiner, Wolfgang; Willich, Stefan N

    2008-12-19

    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(R)) 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). 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. 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. 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.

  15. 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.

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

    Science.gov (United States)

    Roll, Stephanie; Müller-Nordhorn, Jacqueline; Keil, Thomas; Scholz, Hans; Eidt, Daniela; Greiner, Wolfgang; Willich, Stefan N

    2008-01-01

    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. PMID:19099583

  17. Aberrant soluble epoxide hydrolase and oxylipin levels in a porcine arteriovenous graft stenosis model.

    Science.gov (United States)

    Terry, Christi M; Carlson, Mary L; He, Yuxia; Ulu, Arzu; Morisseau, Christophe; Blumenthal, Donald K; Hammock, Bruce D; Cheung, Alfred K

    2014-01-01

    Synthetic arteriovenous grafts (AVGs) used for hemodialysis frequently fail due to the development of neointimal hyperplasia (NH) at the vein-graft anastomosis. Inflammation and smooth-muscle cell (SMC) and myofibroblast proliferation and migration likely play an important role in the pathogenesis of NH. Epoxyeicosatrienoic acids (EETs), the products of the catabolism of arachidonic acid by cytochrome P450 enzymes, possess anti-inflammatory, antiproliferative, antimigratory and vasodilatory properties that should reduce NH. The degradation of vasculoprotective EETs is catalyzed by the enzyme, soluble epoxide hydrolase (sEH). sEH upregulation may thus contribute to NH development by the enhanced removal of vasculoprotective EETs. In this study, sEH, cytochrome P450 and EETs were examined after AVG placement in a porcine model to explore their potential roles in AVG stenosis. Increased sEH protein expression, decreased P450 epoxygenase activity and dysregulation of 5 oxylipin mediators were observed in the graft-venous anastomotic tissues when compared to control veins. Pharmacological inhibitors of sEH decreased the growth factor-induced migration of SMCs and fibroblasts, although they had no significant effect on the proliferation of these cells. These results provide insights on epoxide biology in vascular disorders and a rationale for the development of novel pharmacotherapeutic strategies to prevent AVG failure due to NH and stenosis. © 2014 S. Karger AG, Basel.

  18. Endovascular stent grafting: a review

    International Nuclear Information System (INIS)

    Kribs, S.

    2001-01-01

    Endovascular stent grafts are intravascular devices composed of surgical graft material and a metallic frame, (Fig. 1). Their main application has been to treat aneurysms, but they have been used in vascular trauma and are being investigated for use in occlusive disease. Their advantage in treating aneurysms over conventional surgical treatment is that they are loaded into relatively small delivery systems (Fig. 2) and can be introduced to the area of interest from a remote site - usually the femoral artery. This avoids the morbidity of surgical exposure in difficult sites, such as the thoracic aorta, and lessens the cardiovascular stress to patients by eliminating the need to surgically cross-clamp the vessel being treated. The first description of abdominal aortic aneurysm exclusion by an endovascular stent graft was provided by Parodi and colleagues in 1991. Much of the early clinical experience in endovascular stent grafting was obtained from centres in Australia and Europe, and they are now reporting midterm follow-up data. There are now many centres in Canada and the United States involved in endovascular research and practice. (author)

  19. Vacuum assisted closure in vascular surgery.

    Science.gov (United States)

    Beno, M; Martin, J; Sager, P

    2011-01-01

    Vacuum assisted closure (VAC-therapy) is a well established method in nearly all surgical disciplines. The aim is to present the efficiency of vacuum assisted closure in the treatment of acute and chronic wounds in patients admitted in the department of vascular surgery. Within the year 2008 there were 59 patients (44 men, 15 women) treated with VAC therapy in our Department of Vascular surgery (Landshut, Germany). VAC was used 22x (37.28 %) in therapy of ulcus cruris (venous, arterial, mixed genesis), 15x (25.42%) in patients with diabetic foot syndrome, 12x (20.33%) in secondary healing wounds and infected wounds, 5x (8.47%) in wounds after several injuries and soft skin tissue infections and 5x (8.47%) in wound infections connected with vascular graft infections after vascular revascularization. VAC therapy seems to be very effective in the management of patients with venous ulcers, especially after a proper surgical treatment (100%), patients with soft skin tissue infections (100%) and secondary healing wounds (100%) especially in combination with MESH-Grafting. In patients with diabetic foot syndrome (80%) and peripheral arterial occlusive disease (72.7%), an evaluation of peripheral blood perfusion and revascularization prior to VAC therapy is often necessary. Although VAC was used 5x in the therapy of infected vascular grafts, successful preservation of infected graft material was observed in only one case (infection of PTFE femoro-popliteal bypass graft). Vacuum assisted closure in vascular surgery proved to be simple and efficient method in therapy of acute and chronic wounds. The efficiency of VAC systems in therapy of infected graft material after revascularization needs further studies (Tab. 3, Ref. 10).

  20. Role of graft oversizing in the fixation strength of barbed endovascular grafts.

    Science.gov (United States)

    Kratzberg, Jarin A; Golzarian, Jafar; Raghavan, Madhavan L

    2009-06-01

    The role of endovascular graft oversizing on risk of distal graft migration following endovascular aneurysm repair for abdominal aortic aneurysm is poorly understood. A controlled in vitro investigation of the role of oversizing in graft-aorta attachment strength for endovascular grafts (EVGs) with barbs was performed. Barbed stent grafts (N = 20) with controlled graft oversizing varying from 4-45% were fabricated while maintaining other design variables unchanged. A flow loop with physiological flow characteristics and a biosynthetic aortic aneurysm phantom (synthetic aneurysm model with a bovine aortic neck) were developed. The stent grafts were deployed into the aortic neck of the bio-synthetic aortic aneurysm phantom under realistic flow conditions. Computed tomography imaging of the graft-aorta complex was used to document attachment characteristics such as graft apposition, number of barbs penetrated, and penetration depth and angle. The strength of graft attachment to the aortic neck was assessed using mechanical pullout testing. Stent grafts were categorized into four groups based on oversizing: 4-10%; 11-20%; 21-30%; and greater than 30% oversizing. Pullout force, a measure of post-deployment fixation strength was not different between 4-10% (6.23 +/- 1.90 N), 11-20% (6.25 +/- 1.84 N) and 20-30% (5.85 +/- 1.89 N) groups, but significantly lower for the group with greater than 30% oversizing (3.67 +/- 1.41 N). Increasing oversizing caused a proportional decrease in the number of barbs penetrating the aortic wall (correlation = -0.83). Of the 14 barbs available in the stent graft, 89% of the barbs (12.5 of 14 on average) penetrated the aortic wall in the 4-10% oversizing group while only 38% (5.25 of 14) did for the greater than 30% group (P barb penetration were found to be positively correlated to pullout force. Greater than 30% graft oversizing affects both barb penetration and graft apposition adversely resulting in a low pullout force in this in vitro

  1. 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.

  2. [Vascular access for haemodyalisis. Comparative analysis of the mechanical behaviour of native vessels and prosthesis].

    Science.gov (United States)

    Bia, D; Zócalo, Y; Armentano, R; Pérez, H; Cabrera, E; Saldías, M; Galli, C; Alvarez, I

    2006-01-01

    The prosthesis nowadays used in the vascular access for haemodialysis have low patency rates, mainly due to the luminal obstruction, determined by the intimal hyperplasia. Several factors have been related to de development of intimal hyperplasia and graft failure. Among them are the differences in the biomechanical properties between the prosthesis and the native vessels. In the searching for vascular prosthesis that overcomes the limitations of the currently used, the cryopreserved vessels (cryografts) appear as an alternative of growing interest. However, it is unknown if the mechanical differences or mismatch between prosthesis and native vessels are lesser when using cryografts. To characterize and compare the biomechanical behaviour of native vessels used in vascular access and cryografts. Additionally, segments of expanded polytetrafluoroethylene (ePTFE) were also evaluated, so as to evaluate the potential biomechanical advantages of the cryografts respect to synthetic prosthesis used in vascular access. Segments from human humeral (n = 12), carotid (n = 12) and femoral (n = 12) arteries, and saphenous vein (n = 12), were obtained from 6 multiorgan donors. The humeral arteries were studied in fresh state. The other segments were divided into two groups, and 6 segments from each vessel were studied in fresh state, while the remaining 6 segments were evaluated after 30 days of criopreservation. For the mechanical evaluation the vascular segments and 6 segments of ePTFE were mounted in a circulation mock and submitted to haemodynamic conditions similar to those of the in vivo. Instantaneous pressure (Konigsberg) and diameter (Sonomicrometry) were measured and used to calculate the viscous and elastic indexes, the compliance, distensibility and characteristic impedance. For each mechanical parameter studied, the mismatch between the prosthesis and the native vessel was evaluated. The ePTFE was the prosthesis with the higher mechanical mismatch (p vascular

  3. 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

  4. Bone graft viability evaluated by three phase bone scan

    International Nuclear Information System (INIS)

    Ljiljana Jaukovic Rajko Spaic; Marijan Novakovic; Srbislav Stosic

    2004-01-01

    Bone defects resulting war injury can be replaced by microvascular bone grafts from fibula. Aim: The aim of this study was to assess the value of three phase (3P) bone scintigraphy in the early detection of the bone graft complications. Method: 3P bone scans were performed in four patients (two after mandible reconstruction with micro vascular fibular bone grafts, one after fibular transplantation for ulnar and one with humeral reconstruction). First dynamic phase scan was performed immediately after iv injection of 740 MBq Tc- 99m DPD, acquiring 15 two seconds duration frames. Second, early static scan was performed during next 300 seconds, and third, delayed scan three hours later. All scans were obtained under the bone graft region. The scans were evaluated using ROI under graft region and the corresponding contra lateral area. Blood flow in graft region was determined using first phase scan, and tracer uptake in the same region was determined using second and third phase scans. Results: in all patients blood flow in graft region was particularly normal. Tracer uptake in one of two patients with mandible reconstruction was diffusely increased in graft, strongly suggesting infection; In the other patient delayed scan showed no tracer uptake in graft center .Both patients with ulnar and humeral reconstruction showed only slightly decreased tracer uptake in bone grafts. 3 phase bone scintigraphy may play a role in the evaluation of bone graft viability by predicting the infection and necrosis. (authors)

  5. Synthetic Cannabinoids

    Directory of Open Access Journals (Sweden)

    Aslihan Okan Ibiloglu

    2017-09-01

    Full Text Available Synthetic cannabinoids which is a subgroup of cannabinoids are commonly used for recreational drug use throughout the whole world. Although both marijuana and synthetic cannabinoids stimulate the same receptors, cannabinoid receptor 1 (CB1 and cannabinoid receptor 2 (CB2, studies have shown that synthetic cannabinoids are much more potent than marijuana. The longer use of synthetic cannabinoids can cause severe physical and psychological symptoms that might even result in death, similar to many known illicit drugs. Main treatment options mostly involve symptom management and supportive care. The aim of this article is to discuss clinical and pharmacological properties of the increasingly used synthetic cannabinoids. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2017; 9(3.000: 317-328

  6. 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...

  7.  Evaluation of the humoral and cellular immune responses after implantation of a PTFE vascular prosthesis.

    Science.gov (United States)

    Skóra, Jan; Pupka, Artur; Dorobisz, Andrzej; Barć, Piotr; Korta, Krzysztof; Dawiskiba, Tomasz

    2012-07-02

    The experiment was designed in order to determine the immunological processes that occur during the healing in synthetic vascular grafts, especially to establish the differences in the location of the complement system proteins between the proximal and distal anastomosis and the differences in the arrangement of inflammatory cells in those anastomoses. The understanding of those processes will provide a true basis for determining risk factors for complications after arterial repair procedures. The experiment was carried out on 16 dogs that underwent implantation of unilateral aorto-femoral bypass with expanded polytetrafluoroethylene (ePTFE). After 6 months all animals were euthanized to dissect the vascular grafts. Immunohistochemical assays and electron microscopic examinations were performed. Immunohistochemical findings in the structure of neointima between anastomoses of vascular prostheses demonstrated significant differences between humoral and cellular responses. The area of proximal anastomosis revealed the presence of fibroblasts, but no macrophages were detected. The histological structure of the proximal anastomosis indicates that inflammatory processes were ended during the prosthesis healing. The immunological response obtained in the distal anastomosis corresponded to the chronic inflammatory reaction with the presence of macrophages, myofibroblasts and deposits of complement C3. The identification of differences in the presence of macrophages and myofibroblasts and the presence of the C3 component between the anastomoses is the original achievement of the present study. In the available literature, no such significant differences have been shown so far in the humoral and cellular immune response caused by the presence of an artificial vessel in the arterial system.

  8. Vacuum-assisted wound closure in vascular surgery - clinical and cost benefits in a developing country

    Directory of Open Access Journals (Sweden)

    Končar Igor

    2016-01-01

    Full Text Available Background/Aim. Surgical and chronic wounds in vascular patients might contribute to limb loss and death. Vacuum-assisted closure (VAC - Kinetic Concepts, Inc. (KCI, has been increasingly used in Western Europe and the USA clinical practice for 15 years. Advantages of this method are faster wound healing, wound approximation, lower wound related treatment costs and improved quality of life during treatment. Evidence related to the usage of VAC therapy in vascular patients and cost effectiveness of VAC therapy in a developing country are lacking. The aim of this study was to explore results of VAC therapy in vascular surgery comparing to conventional methods and to test cost effects in a developing country like Serbia. Methods. All patients with wound infection or dehiscence operated at the tertiary vascular university clinic in the period from January 2011 - January 2012, were treated with VAC therapy. The primary endpoint was wound closure, while secondary endpoints were hospital stay, the number of weekly dressings, costs of wound care, working time of medical personnel. The patients were divided into groups according to the wound type and location: wound with exposed synthetic vascular implant (25%, laparotomy (13%, foot amputation (29%, major limb amputation (21%, fasciotomy (13%. The results of primary and secondary endpoint were compared with the results of conventional treatment during the previous year. Results. There was one death (1/42, 2.38% and one limb loss (1/12, 2.38% in the VAC group, and 8 deaths (8/38, 21.05% and 5 (5/38, 13.15% limb losses in the patients treated with conventional therapy. In the VAC group there was one groin bleeding (1/12, 2.38%, one groin reinfection (1/12, 2.38% and one resistance to therapy with a consequent limb loss. Costs of hospital stay (p < 0.001 and nursing time (p < 0.001 were reduced with VAC therapy in the group with exposed graft. Conclusion. VAC therapy is the effective method for care of

  9. 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.

  10. 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.

  11. 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

  12. Comparing frozen saphenous vein with Gore-tex in vascular access for chronic hemodialysis.

    Science.gov (United States)

    Mousavi, Seyed Reza; Moatamedi, Mohammad Reza Kalantar; Me Akbari, Mohamad

    2011-10-01

    Performing chronic hemodialysis in patients suffering from end-stage renal disease needs a suitable vascular access like arteriovenous fistula in the upper limbs and bridge fistula in the upper or lower limbs, and also use of permanent and temporary catheters. The purpose of this study is to compare frozen saphenous vein versus using synthetic Gore-tex vascular graft for A-V fistula. In the prospective randomized study, 70 patients needing for dialysis access were randomly divided into two groups. We performed the frozen saphenous vein A-V fistula in the test group and the Gore-tex fistula in the control group. An assessment included function criteria (fistula thrill and murmur) and complications (infection and thrombosis) in planned intervals. At the end of the follow-up period, the flow rates of all fistulas were assessed by Doppler sonography. The data were compared. Comparing the function criteria (fistula murmur and thrill) and the flow rate of the test group (frozen saphenous A-V fistula) and the control group (Gore-tex method) showed no significant difference and also no significant difference between two groups in thrombosis. Infection rate of the Gore-tex method was significantly high (p Gore-tex arteriovenous graft in some aspects. © 2011 The Authors; Hemodialysis International © 2011 International Society for Hemodialysis.

  13. Vascular injuries during gynecological laparoscopy: the vascular surgeon's advice

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    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.

  14. Imaging after vascular gene therapy

    International Nuclear Information System (INIS)

    Manninen, Hannu I.; Yang, Xiaoming

    2005-01-01

    Targets for cardiovascular gene therapy currently include limiting restenosis after balloon angioplasty and stent placement, inhibiting vein bypass graft intimal hyperplasia/stenosis, therapeutic angiogenesis for cardiac and lower-limb ischemia, and prevention of thrombus formation. While catheter angiography is still standard method to follow-up vascular gene transfer, other modern imaging techniques, especially intravascular ultrasound (IVUS), magnetic resonance (MR), and positron emission tomography (PET) imaging provide complementary information about the therapeutic effect of vascular gene transfer in humans. Although molecular imaging of therapeutic gene expression in the vasculatures is still in its technical development phase, it has already offered basic medical science an extremely useful in vivo evaluation tool for non- or minimally invasive imaging of vascular gene therapy

  15. Synthetic oils

    Science.gov (United States)

    Hatton, R. E.

    1973-01-01

    Synthetic lubricants are discussed by chemical class and their general strengths and weaknesses in terms of lubrication properties are analyzed. Comparative ratings are given for 14 chemical classes and are used as a guide for lubricant selection. The effects of chemical structure on the properties of the lubricant are described with special emphasis on thermal stability. The diversity of synthetic lubricants which is provided by the wide range of properties permits many applications, some of which are reported.

  16. Transabdominal sacrocolpopexy with autologous rectus fascia graft.

    Science.gov (United States)

    Abraham, Nitya; Quirouet, Adrienne; Goldman, Howard B

    2016-08-01

    Extrusion and infection are potential postoperative complications when using synthetic mesh for abdominal sacrocolpopexy. Long-term follow-up in the Colpopexy and Urinary Reduction Efforts (CARE) trial revealed an estimated 9.9 % risk of mesh extrusion. There are 26 reports of spondylodiscitis after sacrocolpopexy with synthetic mesh. These surgical risks may be decreased by using autologous fascia. To date, there have been no reports of extrusion or spondylodiscitis after using autologous fascia for sacrocolpopexy. This video demonstrates transabdominal sacrocolpopexy with an autologous rectus fascia graft. A 76-year-old woman with symptomatic stage 3 prolapse also had a history of diverticulitis and sigmoid abscess requiring sigmoid colectomy with end colostomy and incidental left ureteral transection with subsequent left nephrostomy tube placement. She presented for colostomy reversal, ureteral reimplantation, and prolapse repair. Given the need for concomitant colon and ureteral reconstruction, the risk of infection was potentially higher if synthetic mesh were used. The patient therefore underwent transabdominal sacrocolpopexy with autologous rectus fascia graft. At 4 months' follow-up the patient reported resolution of her symptoms and on examination she had no pelvic organ prolapse. Transabdominal sacrocolpopexy using autologous rectus fascia graft is a feasible option, especially in cases in which infection and synthetic mesh extrusion risks are potentially higher.

  17. 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.

  18. Peripheral vascular injuries

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    Celal Yavuz

    2009-01-01

    Full Text Available Aim: To determine etiology and management in patients with peripheral vascular trauma.Materials and Methods: From 2005 to 2006 with a diagnosis of peripheral artery injury, 69 cases admitted to Diyarbakır State Hospital Department of Cardiovascular surgery.Results: These cases have been respectively reviewed. The causes of injuries were; penetrating injuries in 60 cases (87%, blunt trauma in seven cases (10% and gunshot injuries in two cases (3%. In 53 cases (74% upper extremity, in 15 cases (21% lower extremity was involved. As a surgical procedure, in 34 cases (47% end-to-end anastomosis, in 28 cases (39% lateral suture, in five cases (7% venous graft interposition, in five cases (7% ligation was performed.Conclusion: Early intervention, transfusion of fluid and blood, systemic anticoagulation, preoperative and postoperative detailed debridement decreased the morbidity and mortality rates.

  19. Grafting and curing

    International Nuclear Information System (INIS)

    Garnett, J.L.; Loo-Teck Ng; Visay Viengkhou

    1998-01-01

    Progress in radiation grafting and curing is briefly reviewed. The two processes are shown to be mechanistically related. The parameters influencing yields are examined particularly for grafting. For ionising radiation grafting systems (EB and gamma ray) these include solvents, substrate and monomer structure, dose and dose-rate, temperature and more recently role of additives. In addition, for UV grafting, the significance of photoinitiators is discussed. Current applications of radiation grafting and curing are outlined. The recent development of photoinitiator free grafting and curing is examined as well as the potential for the new excimer laser sources. The future application of both grafting and curing is considered, especially the significance of the occurrence of concurrent grafting during cure and its relevance in environmental considerations

  20. Synthetic environments

    Science.gov (United States)

    Lukes, George E.; Cain, Joel M.

    1996-02-01

    The Advanced Distributed Simulation (ADS) Synthetic Environments Program seeks to create robust virtual worlds from operational terrain and environmental data sources of sufficient fidelity and currency to interact with the real world. While some applications can be met by direct exploitation of standard digital terrain data, more demanding applications -- particularly those support operations 'close to the ground' -- are well-served by emerging capabilities for 'value-adding' by the user working with controlled imagery. For users to rigorously refine and exploit controlled imagery within functionally different workstations they must have a shared framework to allow interoperability within and between these environments in terms of passing image and object coordinates and other information using a variety of validated sensor models. The Synthetic Environments Program is now being expanded to address rapid construction of virtual worlds with research initiatives in digital mapping, softcopy workstations, and cartographic image understanding. The Synthetic Environments Program is also participating in a joint initiative for a sensor model applications programer's interface (API) to ensure that a common controlled imagery exploitation framework is available to all researchers, developers and users. This presentation provides an introduction to ADS and the associated requirements for synthetic environments to support synthetic theaters of war. It provides a technical rationale for exploring applications of image understanding technology to automated cartography in support of ADS and related programs benefitting from automated analysis of mapping, earth resources and reconnaissance imagery. And it provides an overview and status of the joint initiative for a sensor model API.

  1. Protective effect of dexmedetomidine in coronary artery bypass grafting surgery

    OpenAIRE

    REN, JIANJUN; ZHANG, HUIJUN; HUANG, LINING; LIU, YUE; LIU, FENGQIN; DONG, ZHENMING

    2013-01-01

    The aim of this study was to observe the impact of dexmedetomidine on postoperative myocardial injury in patients undergoing off-pump coronary artery bypass (OPCAB) grafting. One hundred and sixty-two patients who were undergoing OPCAB surgery were randomly divided into control and dexmedetomidine groups (groups C and Dex, respectively). Following the first vascular anastomosis grafting, the patients in group Dex received a continuous intravenous infusion of 0.2?0.5 ?g/kg/h dexmedetomidine, u...

  2. 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.

  3. 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.

  4. Modification of polyetherurethane for biomedical application by radiation induced grafting. II. Water sorption, surface properties, and protein adsorption of grafted films

    International Nuclear Information System (INIS)

    Jansen, B.; Ellinghorst, G.

    1984-01-01

    A series of polyetherurethane films grafted by means of gamma radiation with hydrophilic or reactive monomers (2-hydroxyethyl methacrylate, 2,3-epoxypropyl methacrylate, 2,3-dihydroxypropyl methacrylate, and acrylamide) and partially chemically modified were subjected to various physico-chemical investigation methods involving water sorption, contact angle, and protein adsorption measurements. From contact angle data the interfacial free energy gamma sw between grafted films and water was calculated. It was found that the water uptake of grafted films increases with grafting yield or, in the case of grafted and afterwards chemically modified films, with reaction yield; the diffusion coefficient of water in the modified films also increases with grafting yield. Contact angle studies revealed all grafted films to have surfaces more hydrophilic than the ungrafted trunk polymer. The degree of hydrophilicity--especially of HEMA-grafted films--strongly depends on grafting conditions. For some grafted samples with high surface hydrophilicity very low interfacial free energies approaching zero were measured. The study of the competitive adsorption of bovine serum albumin, gamma-globulin, and fibrinogen from a synthetic protein solution onto modified films showed that the adsorption of albumin increases markedly with increasing grafting yields, whereas the fibrinogen and gamma-globulin adsorption only slightly increases. A correlation between interfacial free energy and protein adsorption in the sense of the minimum interfacial free energy hypothesis was found only for samples with grafting yields below 5%. At higher grafting yields the increased surface area complicates the analysis

  5. 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.

  6. Influences of irradiation on the anastomotic sites of artificial graft

    International Nuclear Information System (INIS)

    Ogawa, Junichi; Inoue, Hiroshi; Koide, Shirosaku; Kawada, Shimei; Shotsu, Akira

    1989-01-01

    To examine the acute influences of irradiation on the anastomotic sites of EPTFE vascular grafts, experimental study was performed using canine dogs. After replacement of superior vena cava and bilateral femoral arteries with EPTFE grafts, a total of 20 to 100 Gy doses were given at the anastomotic sites of superior vena cava and right femoral artery. There were no degradation of grafts themselves or rupture in the anastomoses at cumulative anastomotic sites of superior vena cava, stenoses and/or overgrowth of granulation tissues were observed, although at those of right femoral artery, no remarkable differences were observed between dogs which received irradiation and those which did not receive. (author)

  7. Synthetic Rutile

    International Nuclear Information System (INIS)

    Burastero, J.

    1975-01-01

    This work is about the laboratory scale investigation of the conditions in the rutile synthetic production from one me nita in Aguas Dulces reservoir. The iron mineral is chlorinated and volatilized selectively leaving a residue enriched in titanium dioxide which can be used as a substitute of rutile mineral

  8. Vascular dementia

    African Journals Online (AJOL)

    Adele

    2003-12-10

    Dec 10, 2003 ... ischaemic VaD includes multiple lacunes and subcortical arteriosclerotic encephalopathy (Binswanger's disease) and imaging shows multiple deep ... culitis, multiple sclerosis, acute demyelinating encephalomy- ... Table I. The NINDS-AIREN criteria for the diagnosis of Vascular Dementia. 12. Require both ...

  9. VASCULAR SURGERY

    African Journals Online (AJOL)

    2016-06-02

    Jun 2, 2016 ... with the literature from South Africa over the last four decades, and reflects the high rate of interpersonal violence in the country.14,15 As expected, cervical ... via the intact circle of Willis in young patients is the most likely explanation for the lack of strokes. Five patients were referred to the Durban vascular ...

  10. Ultrasound -- Vascular

    Science.gov (United States)

    ... waves from passing into your body. The sonographer (ultrasound technologist) or radiologist then places the transducer on the ... is specialized and is best performed by a technologist and physician with experience in vascular ultrasound imaging. top of page Additional Information and Resources ...

  11. Vacuum-assisted wound closure in vascular surgery--clinical and cost benefits in a developing country.

    Science.gov (United States)

    Koncar, Igor; Cvetković, Slobodan; Dragas, Marko; Pejkić, Sinisa; Lazović, Goran; Banzić, Igor; Zuvela, Marinko; Marković, Miroslav; Davidović, Lazar

    2016-01-01

    BACKGROUND/AIM. Surgical and chronic wounds in vascular patients might contribute to limb loss and death. Vacuum-assisted closure (VAC)--Kinetic Concepts, Inc. (KCI), has been increasingly used in Western Europe and the U.S.A. clinical practice for 15 years. Advantages of this method are faster wound healing, wound approximation, lower wound related treatment costs and improved quality of life during treatment. Evidence related to the usage of VAC therapy in vascular patients and cost effectiveness of VAC therapy in a developing country are lacking. The aim of this study was to explore results of VAC therapy in vascular surgery comparing to conventional methods and to test cost effects in a developing country like Serbia. All patients with wound infection or dehiscence operated at the tertiary vascular university clinic in the period from January 2011-January 2012, were treated with VAC therapy. The primary endpoint was wound closure, while secondary endpoints were hospital stay, the number of weekly dressings, costs of wound care, working time of medical personnel. The patients were divided into groups according to the wound type and location: wound with exposed synthetic vascular implant (25%), laparotomy (13%), foot amputation (29%), major limb amputation (21%), fasciotomy (13%). The results of primary and secondary endpoint were compared with the results of conventional treatment during the previous year. There was one death (1/42, 2.38%) and one limb loss (1/12, 2.38%) in the VAC group, and 8 deaths (8/38, 21.05%) and 5 (5/38, 13.15%) limb losses in the patients treated with conventional therapy. In the VAC group there was one groin bleeding (1/12, 2.38%), one groin reinfection (1/12, 2.38%) and one resistance to therapy with a consequent limb loss. Costs of hospital stay (p VAC therapy in the group with exposed graft. VAC therapy is the effective method for care of complicated wounds in vascular surgery. Patients with infection of wound with the exposed

  12. Pancreatic transplantation: Radiologic evaluation of vascular complications

    International Nuclear Information System (INIS)

    Snider, J.F.; Hunter, D.W.; Kuni, C.C.; Castaneda-Zuniga, W.R.; Letourneau, J.G.

    1991-01-01

    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

  13. 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.

  14. Long-term internal thoracic artery bypass graft patency and geometry assessed by multidetector computed tomography

    DEFF Research Database (Denmark)

    Zacho, Mette; Damgaard, Sune; Lilleoer, Nikolaj Thomas

    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...

  15. Differential contributions of graft-derived and host-derived cells in tissue regeneration/remodeling after fat grafting.

    Science.gov (United States)

    Doi, Kentaro; Ogata, Fusa; Eto, Hitomi; Kato, Harunosuke; Kuno, Shinichiro; Kinoshita, Kahori; Kanayama, Koji; Feng, Jingwei; Manabe, Ichiro; Yoshimura, Kotaro

    2015-06-01

    Recent research indicates that the adipose tissue of nonvascularized grafts is completely remodeled within 3 months, although origins of next-generation cells are unclear. Inguinal fat pads of green fluorescent protein mice and wild-type mice were cross-transplanted beneath the scalp. At 1, 2, 4, and 12 weeks after transplantation, grafted fat was harvested, weighed, and analyzed through immunohistochemistry, whole-mount staining, and flow cytometry of cell isolates. Bone marrow of green fluorescent protein mice was transplanted to wild-type mice (after irradiation). Eight weeks later, these mice also received fat grafts, which were analyzed as well. The majority of host-derived cells detected during remodeling of grafted fat were macrophages (>90 percent at the early stage; 60 percent at 12 weeks). Cell origins were analyzed at 12 weeks (i.e., when completely regenerated). At this point, mature adipocytes were largely derived from adipose-derived stem/stromal cells of grafts. Although vascular wall constituents were chiefly graft derived, vascular endothelial cells originated equally from graft and host bone marrow. Adipose-derived stem/stromal cells of regenerated fat were an admixture of grafted, host nonbone marrow, and host bone marrow cells. The above findings underscore the importance of adipose stem/stromal cells in the grafted fat for adipocyte regeneration. Host bone marrow and local tissues contributed substantially to capillary networks and provided new adipose-derived stem/stromal cells. An appreciation of mechanisms that are operant in this setting stands to improve clinical outcomes of fat grafting and cell-based therapies.

  16. Vascular injuries after bear attacks: Incidence, surgical challenges and outcome.

    Science.gov (United States)

    Wani, Mohd Lateef; Ahangar, Abdul Gani; Lone, Gh Nabi; Lone, Reyaz Ahmad; Ashraf, Hakeem Zubair; Dar, Abdul Majeed; Bhat, M A; Singh, Shyam; Bijli, Akram Hussain; Irshad, Ifat

    2011-01-01

    Bear mauling is rarely reported in medical literature due to its rare occurrence. Present study was undertaken to describe the pattern and management of bear maul vascular injuries in Kashmir. Study of patients with bear maul vascular injury from 1(st) Jan 2004 to 31(st) Dec. 2008. Fifteen patients with bear maul vascular injury were studied. All patients of bear maul without vascular injury were excluded from the study. Most of the patients were treated by reverse saphenous vein graft or end to end anastomosis. Most common complication was wound infection (20%) followed by graft occlusion (13.33%). There was no operative death. Bear attacks are very common in Kashmir. Vascular injury due to bear maul needs prompt resuscitation and revascularization. Results are very good provided timely intervention for revascularization is done.

  17. Vascular neoplasms.

    Science.gov (United States)

    Williams, H B

    1980-07-01

    Vascular neoplasms in the broad sense represent a very common group of tumors or hamartomas that show great variability in gross appearance, microscopic appearance, and clinical course. Generally, neoplasms are composed of one cell type, but vascular neoplasms are collections of endothelial-lined tubes or tubules with connective tissue walls that may contain smooth muscle cells, pericytes, and nerve elements according to the specific tissues of origin. The classification of vascular neoplasms as outlined in this article attempts to delineate each tumor or hamartoma according to its histologic appearance and clinical behavior. The clinical course ranges from completely benign, self-involuting malformations such as the strawberry hemangioma to highly malignant angiosarcomas with their rapid growth and frequent metastases. Defects in the lymphatic system show gradations from simple lymphangiomas through lymphedema and lymphangiectasia, which can probably be explained by faulty embryologic development. Management of these lesions has been discussed, including brief descriptions of most of the currently accepted treatment methods for these frequently encountered clinical problems.

  18. Hydrophilicity, Viscoelastic, and Physicochemical Properties Variations in Dental Bone Grafting Substitutes

    Directory of Open Access Journals (Sweden)

    Branko Trajkovski

    2018-01-01

    Full Text Available The indication-oriented Dental Bone Graft Substitutes (DBGS selection, the correct bone defects classification, and appropriate treatment planning are very crucial for obtaining successful clinical results. However, hydrophilic, viscoelastic, and physicochemical properties’ influence on the DBGS regenerative potential has poorly been studied. For that reason, we investigated the dimensional changes and molecular mobility by Dynamic Mechanical Analysis (DMA of xenograft (cerabone®, synthetic (maxresorb®, and allograft (maxgraft®, Puros® blocks in a wet and dry state. While no significant differences could be seen in dry state, cerabone® and maxresorb® blocks showed a slight height decrease in wet state, whereas both maxgraft® and Puros® had an almost identical height increase. In addition, cerabone® and maxresorb® blocks remained highly rigid and their damping behaviour was not influenced by the water. On the other hand, both maxgraft® and Puros® had a strong increase in their molecular mobility with different damping behaviour profiles during the wet state. A high-speed microscopical imaging system was used to analyze the hydrophilicity in several naturally derived (cerabone®, Bio-Oss®, NuOss®, SIC® nature graft and synthetic DBGS granules (maxresorb®, BoneCeramic®, NanoBone®, Ceros®. The highest level of hydrophilicity was detected in cerabone® and maxresorb®, while Bio-Oss® and BoneCeramic® had the lowest level of hydrophilicity among both naturally derived and synthetic DBGS groups. Deviations among the DBGS were also addressed via physicochemical differences recorded by Micro Computed Tomography, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, X-ray powder Diffractometry, and Thermogravimetric Analysis. Such DBGS variations could influence the volume stability at the grafting site, handling as well as the speed of vascularization and bone regeneration. Therefore, this study initiates a new

  19. 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.

  20. Autogenous Corticocancellous Iliac Bone Graft in Reconstruction of ...

    African Journals Online (AJOL)

    Mandible resection and subsequent defect created lead to aesthetic and functional abnormalities. The surgical reconstruction of the defect is a major challenge in maxillofacial surgery. Lack of appropriate facilities and the high cost of newer modalities made the use of non-vascularized iliac bone graft in reconstruction of ...

  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. Osseous scintigraphy and auxiliary graft

    International Nuclear Information System (INIS)

    Khelifa, F.; Siles, S.; Puech, B.

    1992-01-01

    The scintigraphy could be a good way to survey the osseous graft: three cases are studied in which were recognized the presence of a graft, surinfection, graft lysis, pseudo-arthrosis, algodystrophy. 8 refs., 5 figs

  3. Meniscal allograft transplantation. Part 1: systematic review of graft biology, graft shrinkage, graft extrusion, graft sizing, and graft fixation.

    Science.gov (United States)

    Samitier, Gonzalo; Alentorn-Geli, Eduard; Taylor, Dean C; Rill, Brian; Lock, Terrence; Moutzouros, Vasilius; Kolowich, Patricia

    2015-01-01

    To provide a systematic review of the literature regarding five topics in meniscal allograft transplantation: graft biology, shrinkage, extrusion, sizing, and fixation. A systematic literature search was conducted using the PubMed (MEDLINE), ScienceDirect, and EBSCO-CINAHL databases. Articles were classified only in one topic, but information contained could be reported into other topics. Information was classified according to type of study (animal, in vitro human, and in vivo human) and level of evidence (for in vivo human studies). Sixty-two studies were finally included: 30 biology, 3 graft shrinkage, 11 graft extrusion, 17 graft size, and 6 graft fixation (some studies were categorized in more than one topic). These studies corresponded to 22 animal studies, 22 in vitro human studies, and 23 in vivo human studies (7 level II, 10 level III, and 6 level IV). The principal conclusions were as follows: (a) Donor cells decrease after MAT and grafts are repopulated with host cells form synovium; (b) graft preservation alters collagen network (deep freezing) and causes cell apoptosis with loss of viable cells (cryopreservation); (c) graft shrinkage occurs mainly in lyophilized and gamma-irradiated grafts (less with cryopreservation); (d) graft extrusion is common but has no clinical/functional implications; (e) overall, MRI is not superior to plain radiograph for graft sizing; (f) graft width size matching is more important than length size matching; (g) height appears to be the most important factor influencing meniscal size; (h) bone fixation better restores contact mechanics than suture fixation, but there are no differences for pullout strength or functional results; and (i) suture fixation has more risk of graft extrusion compared to bone fixation. Systematic review of level II-IV studies, Level IV.

  4. Synthetic Cannabinoids.

    Science.gov (United States)

    Mills, Brooke; Yepes, Andres; Nugent, Kenneth

    2015-07-01

    Synthetic cannabinoids (SCBs), also known under the brand names of "Spice," "K2," "herbal incense," "Cloud 9," "Mojo" and many others, are becoming a large public health concern due not only to their increasing use but also to their unpredictable toxicity and abuse potential. There are many types of SCBs, each having a unique binding affinity for cannabinoid receptors. Although both Δ-tetrahydrocannabinol (THC) and SCBs stimulate the same receptors, cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), studies have shown that SCBs are associated with higher rates of toxicity and hospital admissions than is natural cannabis. This is likely due to SCBs being direct agonists of the cannabinoid receptors, whereas THC is a partial agonist. Furthermore, the different chemical structures of SCBs found in Spice or K2 may interact in unpredictable ways to elicit previously unknown, and the commercial products may have unknown contaminants. The largest group of users is men in their 20s who participate in polydrug use. The most common reported toxicities with SCB use based on studies using Texas Poison Control records are tachycardia, agitation and irritability, drowsiness, hallucinations, delusions, hypertension, nausea, confusion, dizziness, vertigo and chest pain. Acute kidney injury has also been strongly associated with SCB use. Treatment mostly involves symptom management and supportive care. More research is needed to identify which contaminants are typically found in synthetic marijuana and to understand the interactions between different SBCs to better predict adverse health outcomes.

  5. Transcriptomic Analysis Provides Insights into Grafting Union Development in Pecan (Carya illinoinensis).

    Science.gov (United States)

    Mo, Zhenghai; Feng, Gang; Su, Wenchuan; Liu, Zhuangzhuang; Peng, Fangren

    2018-02-05

    Pecan ( Carya illinoinensis ), as a popular nut tree, has been widely planted in China in recent years. Grafting is an important technique for its cultivation. For a successful grafting, graft union development generally involves the formation of callus and vascular bundles at the graft union. To explore the molecular mechanism of graft union development, we applied high throughput RNA sequencing to investigate the transcriptomic profiles of graft union at four timepoints (0 days, 8 days, 15 days, and 30 days) during the pecan grafting process. After de novo assembly, 83,693 unigenes were obtained, and 40,069 of them were annotated. A total of 12,180 differentially expressed genes were identified between by grafting. Genes involved in hormone signaling, cell proliferation, xylem differentiation, cell elongation, secondary cell wall deposition, programmed cell death, and reactive oxygen species (ROS) scavenging showed significant differential expression during the graft union developmental process. In addition, we found that the content of auxin, cytokinin, and gibberellin were accumulated at the graft unions during the grafting process. These results will aid in our understanding of successful grafting in the future.

  6. Advances in radiation grafting

    International Nuclear Information System (INIS)

    Hegazy, El-Sayed A.; AbdEl-Rehim, H.A.; Kamal, H.; Kandeel, K.A.

    2001-01-01

    Graft copolymerization is an attractive means for modifying base polymers because grafting frequently results in the superposition of properties relating to the backbone and pendent chains. Among the various methods for initiating the grafting reaction, ionizing radiation is the cleanest and most versatile method of grafting available. Ion-exchange membranes play an important role in modern technology, especially in separation and purification of materials. The search for improved membrane composition has considered almost every available polymeric material because of its great practical importance. Grafting of polymers with a mixture of monomers is important since different types of chains containing different functional groups are included. A great deal is focused on the waste treatment of heavy and toxic metals from wastewater because of the severe problems of environmental pollution. Functionalized polymers suitable for metal adsorption with their reactive functional groups such as carboxylic and pyridine groups suitable for waste treatment were prepared by radiation grafting method. More reactive chelating groups were further introduced to the grafted copolymer through its functional groups by chemical treatments with suitable reagents. The advances of radiation grafting and possible uses are briefly discussed

  7. Calcar bone graft

    Energy Technology Data Exchange (ETDEWEB)

    Bargar, W.L.; Paul, H.A.; Merritt, K.; Sharkey, N.

    1986-01-01

    A canine model was developed to investigate the use of an autogeneic iliac bone graft to treat the calcar deficiency commonly found at the time of revision surgery for femoral component loosening. Five large male mixed-breed dogs had bilateral total hip arthroplasty staged at three-month intervals, and were sacrificed at six months. Prior to cementing the femoral component, an experimental calcar defect was made, and a bicortical iliac bone graft was fashioned to fill the defect. Serial roentgenograms showed the grafts had united with no resorption. Technetium-99 bone scans showed more uptake at three months than at six months in the graft region. Disulfine blue injection indicated all grafts were perfused at both three and six months. Thin section histology, fluorochromes, and microradiographs confirmed graft viability in all dogs. Semiquantitative grading of the fluorochromes indicated new bone deposition in 20%-50% of each graft at three months and 50%-80% at six months. Although the calcar bone graft was uniformly successful in this canine study, the clinical application of this technique should be evaluated by long-term results in humans.

  8. Advances in radiation grafting

    Science.gov (United States)

    Hegazy, El-Sayed A.; AbdEl-Rehim, H. A.; Kamal, H.; Kandeel, K. A.

    2001-12-01

    Graft copolymerization is an attractive means for modifying base polymers because grafting frequently results in the superposition of properties relating to the backbone and pendent chains. Among the various methods for initiating the grafting reaction, ionizing radiation is the cleanest and most versatile method of grafting available. Ion-exchange membranes play an important role in modern technology, especially in separation and purification of materials. The search for improved membrane composition has considered almost every available polymeric material because of its great practical importance. Grafting of polymers with a mixture of monomers is important since different types of chains containing different functional groups are included. A great deal is focused on the waste treatment of heavy and toxic metals from wastewater because of the severe problems of environmental pollution. Functionalized polymers suitable for metal adsorption with their reactive functional groups such as carboxylic and pyridine groups suitable for waste treatment were prepared by radiation grafting method. More reactive chelating groups were further introduced to the grafted copolymer through its functional groups by chemical treatments with suitable reagents. The advances of radiation grafting and possible uses are briefly discussed.

  9. Effect of calvarial burring on resorption of onlay cranial bone graft.

    Science.gov (United States)

    Hassanein, Aladdin H; Clune, James E; Mulliken, John B; Arany, Praveen R; Rogers, Gary F; Kulungowski, Ann M; Greene, Arin K

    2012-09-01

    Variable resorption occurs whenever calvarial bone graft is used for onlay cranioplasty. The recipient ectocortex may be burred to expose vessels and osteocytes to maximize healing. The purpose of this study was to determine whether abrading the recipient site improves the volume of onlay graft. The parietal bones of 17 rabbits were sectioned into split-thickness and full-thickness grafts. The right frontal cortex was abraded with a bur to punctate bleeding. Pairs of split-thickness (n = 48) or full-thickness (n = 20) grafts were onlayed to the burred right frontal bone and to the nonburred left frontal bone. Micro-computed tomography was used to determine graft volume immediately postoperatively and 16 weeks later. Histology, including tartrate-resistant acid phosphatase staining, was performed to quantify vascular channels and osteoclasts per high-power field 10 days postoperatively. Split-thickness graft volume decreased 58.0% when placed on the burred calvarial site, compared with grafts on the nonburred cortex (28.4%) (P = 0.01). Full-thickness grafts showed a similar trend: greater resorption (39.1%) when onlayed onto abraded calvaria compared with nonburred ectocortex (26.0%) (P = 0.11). Split-thickness graft orientation (cortical vs cancellous side in contact with the recipient site) did not affect resorption (P = 0.67). Onlay grafts placed on the burred recipient site had more vascular channels (11.8) and osteoclasts (5.7), compared with grafts over nonabraded cortex (3.4 and 4.2, respectively) (P cranial bone grafting promotes resorption, possibly by increasing vascularization and osteoclastic activity. This technique cannot be recommended.

  10. Synthetic Botany.

    Science.gov (United States)

    Boehm, Christian R; Pollak, Bernardo; Purswani, Nuri; Patron, Nicola; Haseloff, Jim

    2017-07-05

    Plants are attractive platforms for synthetic biology and metabolic engineering. Plants' modular and plastic body plans, capacity for photosynthesis, extensive secondary metabolism, and agronomic systems for large-scale production make them ideal targets for genetic reprogramming. However, efforts in this area have been constrained by slow growth, long life cycles, the requirement for specialized facilities, a paucity of efficient tools for genetic manipulation, and the complexity of multicellularity. There is a need for better experimental and theoretical frameworks to understand the way genetic networks, cellular populations, and tissue-wide physical processes interact at different scales. We highlight new approaches to the DNA-based manipulation of plants and the use of advanced quantitative imaging techniques in simple plant models such as Marchantia polymorpha. These offer the prospects of improved understanding of plant dynamics and new approaches to rational engineering of plant traits. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  11. Synthetic Brainbows

    KAUST Repository

    Wan, Y.

    2013-06-01

    Brainbow is a genetic engineering technique that randomly colorizes cells. Biological samples processed with this technique and imaged with confocal microscopy have distinctive colors for individual cells. Complex cellular structures can then be easily visualized. However, the complexity of the Brainbow technique limits its applications. In practice, most confocal microscopy scans use different florescence staining with typically at most three distinct cellular structures. These structures are often packed and obscure each other in rendered images making analysis difficult. In this paper, we leverage a process known as GPU framebuffer feedback loops to synthesize Brainbow-like images. In addition, we incorporate ID shuffing and Monte-Carlo sampling into our technique, so that it can be applied to single-channel confocal microscopy data. The synthesized Brainbow images are presented to domain experts with positive feedback. A user survey demonstrates that our synthetic Brainbow technique improves visualizations of volume data with complex structures for biologists.

  12. Novel strategies to improve the patency of vascular prostheses

    NARCIS (Netherlands)

    Heyligers, J.M.M.

    2006-01-01

    Two novel strategies to improve the patency of vascular prostheses are described in this thesis. To improve the outcome of synthetic vascular bypass surgery, cell seeding is a promising concept that has extensively been investigated and is still evolving. To improve the short term effects due to

  13. Novel therapies for hemodialysis vascular access dysfunction: fact or fiction!

    Science.gov (United States)

    Roy-Chaudhury, Prabir; Kelly, Burnett S; Melhem, Murad; Zhang, Jianhua; Li, Jinsong; Desai, Pankaj; Munda, Rino; Heffelfinger, Sue C

    2005-01-01

    Hemodialysis vascular access dysfunction is a major cause of morbidity in the hemodialysis population and contributes significantly to the overall cost of end-stage renal disease programs. At a histological level, most hemodialysis vascular access dysfunction (in both native arteriovenous fistulae and PTFE dialysis access grafts) is due to venous stenosis and thrombosis, secondary to venous neointimal hyperplasia. However, despite a wealth of experimental and clinical data on the use of novel therapeutic interventions that target neointimal hyperplasia in the setting of coronary artery disease, there are unfortunately no effective therapeutic interventions for hemodialysis vascular access dysfunction at the present time. This is particularly unfortunate, since neointimal hyperplasia in the setting of hemodialysis vascular access fistulae and grafts could be the ideal clinical model to test novel therapeutic interventions for neointimal hyperplasia. Copyright 2005 S. Karger AG, Basel.

  14. [Flap repair for vascular prosthesis exposure after artificial blood vessel bypass surgery for critical limb ischemia].

    Science.gov (United States)

    Wu, Wei-wei; Wu, Hao; Zeng, Ang; Bai, Ming; Zeng, Rong; Chen, Yu; Liu, Chang-wei

    2013-08-01

    To investigate the effectiveness of flap repair for vascular prosthesis exposure after the artificial blood vessel bypass surgery for critical limb ischemia. From August 2007 to December 2011, bypass surgery with vascular prosthetic grafts were performed in 192 patients with critical limb ischemia.Five patients among them (2.6%) suffered from vascular prosthesis exposure 6 to 13 days after the previous surgery, including 4 males and 1 female, with a median age of 68 years(arranged from 52 to 81 years). The surgical managements included surgical debridement and local flap or transferred muscle-cutaneous flap repair to preserve the prosthetic vascular grafts. Three patients underwent Z-plasty with local flap repair, while 2 patients underwent transferred rectus abdominis or rectus femoris muscle flap repair of the wounds. After the surgery, prosthetic vascular graft was successfully preserved in 4 of the 5 cases with first intention healing. At a median follow-up of 38 months (arranged from 5 to 57 months), all the 4 limbs were salvaged with patent of the prosthetic grafts.One flap failed to heal and the prosthetic graft had to be removed due to infection and hemorrhage. An above-knee-amputation was performed due to severe limb ischemia. The vascular prosthesis exposure is often a disaster after artificial blood vessel bypass surgery for critical limb ischemia.Local flap or transferred muscle-cutaneous flap repair is an effective surgical management to salvage the exposed graft and the affected limb.

  15. Possible role of mechanical force in regulating regeneration of the vascularized fat flap inside a tissue engineering chamber.

    Science.gov (United States)

    Ye, Yuan; Yuan, Yi; Lu, Feng; Gao, Jianhua

    2015-12-01

    In plastic and reconstructive surgery, adipose tissue is widely used as effective filler for tissue defects. Strategies for treating soft tissue deficiency, which include free adipose tissue grafts, use of hyaluronic acid, collagen injections, and implantation of synthetic materials, have several clinical limitations. With the aim of overcoming these limitations, researchers have recently utilized tissue engineering chambers to produce large volumes of engineered vascularized fat tissue. However, the process of growing fat tissue in a chamber is still relatively limited, and can result in unpredictable or dissatisfactory final tissue volumes. Therefore, detailed understanding of the process is both necessary and urgent. Many studies have shown that mechanical force can change the function of cells via mechanotransduction. Here, we hypothesized that, besides the inflammatory response, one of the key factors to control the regeneration of vascularized fat flap inside a tissue engineering chamber might be the balance of mechanical forces. To test our hypothesis, we intend to change the balance of forces by means of measures in order to make the equilibrium point in favor of the direction of regeneration. If those measures proved to be feasible, they could be applied in clinical practice to engineer vascularized adipose tissue of predictable size and shape, which would in turn help in the advancement of tissue engineering. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. 3D printed scaffolds of calcium silicate-doped β-TCP synergize with co-cultured endothelial and stromal cells to promote vascularization and bone formation.

    Science.gov (United States)

    Deng, Yuan; Jiang, Chuan; Li, Cuidi; Li, Tao; Peng, Mingzheng; Wang, Jinwu; Dai, Kerong

    2017-07-17

    Synthetic bone scaffolds have potential application in repairing large bone defects, however, inefficient vascularization after implantation remains the major issue of graft failure. Herein, porous β-tricalcium phosphate (β-TCP) scaffolds with calcium silicate (CS) were 3D printed, and pre-seeded with co-cultured human umbilical cord vein endothelial cells (HUVECs) and human bone marrow stromal cells (hBMSCs) to construct tissue engineering scaffolds with accelerated vascularization and better bone formation. Results showed that in vitro β-TCP scaffolds doped with 5% CS (5%CS/β-TCP) were biocompatible, and stimulated angiogenesis and osteogenesis. The results also showed that 5%CS/β-TCP scaffolds not only stimulated co-cultured cells angiogenesis on Matrigel, but also stimulated co-cultured cells to form microcapillary-like structures on scaffolds, and promoted migration of BMSCs by stimulating co-cultured cells to secrete PDGF-BB and CXCL12 into the surrounding environment. Moreover, 5%CS/β-TCP scaffolds enhanced vascularization and osteoinduction in comparison with β-TCP, and synergized with co-cultured cells to further increase early vessel formation, which was accompanied by earlier and better ectopic bone formation when implanted subcutaneously in nude mice. Thus, our findings suggest that porous 5%CS/β-TCP scaffolds seeded with co-cultured cells provide new strategy for accelerating tissue engineering scaffolds vascularization and osteogenesis, and show potential as treatment for large bone defects.

  17. Assessment of Vascular Injuries and Reconstruction

    Science.gov (United States)

    Baghi, Iraj; Herfatkar, Mohammad Rasool; Shokrgozar, Leila; Poor-Rasuli, Zahra; Aghajani, Fatemeh

    2015-01-01

    Background: Trauma is the third leading cause of death. In this regard, vascular injury plays a leading role in of morbidity and mortality rates. Objectives: The present study aimed to assess the prevalence of vascular injuries and results of vascular reconstruction at a referral hospital in northern Iran. Patients and Methods: A retrospective observational study assessed 88 consecutive patients with vascular injury admitted to Poursina Hospital, Rasht in northern Iran, from October 2007 to October 2009. All study information was collected retrospectively from hospital charts. Results: Most of the affected patients (87/88) were male with a mean age of 29.12 ± 11.20 years. The mechanism of injury in 39.8% was blunt trauma and penetrating trauma in the rest. Of the 53 injured by penetrating trauma (60.2%), the most common cause was stabbing (94.3%). The most common cause of blunt trauma was road traffic accidents (93.1%). The most common mechanism for vascular injuries in upper extremities was penetrating trauma (86.0%) and in lower extremities was blunt trauma (60.0%). Fasciotomy was performed in 16 patients (18.2%) mostly in the lower extremities. Major amputation was required in 10% of the patients. In upper extremities, the most common type of revascularization was end to end anastomosis, followed by inter-position graft. The most common type of reconstruction in the lower extremity was bypass graft. All patients who underwent major amputation were admitted to the center with a delay of more than 6 hours after injury. Conclusions: Major vascular injuries in our center occurred in young men, frequently because of stab wounds. Popliteal injuries mostly caused by motor vehicle accidents was the second most common arterial injury, followed by combined ulnar and radial injuries. Vascular reconstruction in the first hours after trauma may prevent many unnecessary and preventable amputation procedures. PMID:26839869

  18. Remnant prosthetic graft in revision or limb-salvage surgery: routine complete excision?

    Science.gov (United States)

    Shenouda, Michael; Molena, Emma; Maftei, Nonica; Ali, Tahir

    2014-08-01

    Prosthetic graft occlusion following vascular reconstruction is a major cause of morbidity commonly necessitating further limb-salvage revascularization or life-saving amputation. It is therefore surprising that there is scant data in the literature regarding the optimal management of any remnant prosthetic grafts left in situ. We present a case series of 3 patients with remnant prosthetic graft infection following revisional arterial reconstruction for limb salvage and a literature review on this topic. Three patients presented to our institution with remnant prosthetic graft infection between March 2012 and January 2013. They had all undergone previous infrainguinal bypass surgery with polytetrafluorethylene (PTFE) grafts, which had subsequently thrombosed. Further limb salvage operations with autogenous long saphenous vein bypass in 2 cases and above-knee amputation in 1 case were performed. In all cases, the focus of infection was confirmed to have originated in the redundant remnant PTFE graft left in situ. These grafts were completely excised and the infected wounds were debrided. All patients made a full recovery. Remnant prosthetic grafts left in situ are shown in this series to be a proven nidus for infection. Published data indicate that these infection rates are greatest in revision vascular surgery and when performing amputations. We propose that routine excision of any occluded remnant prosthetic grafts in revision surgery be considered at the time of revascularization to mitigate against the risk of subsequent infection. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. PTFE grafts versus tunneled cuffed catheters for hemodialysis: which is the second choice when arteriovenous fistula is not feasible?

    Science.gov (United States)

    Donati, Gabriele; Cianciolo, Giuseppe; Mauro, Raffaella; Rucci, Paola; Scrivo, Anna; Marchetti, Antonio; Giampalma, Emanuela; Golfieri, Rita; Panicali, Laura; Iorio, Mario; Stella, Andrea; La Manna, Gaetano; Stefoni, Sergio

    2015-02-01

    Vascular access-related complications are still one of the leading causes of morbidity in hemodialysis patients. The aim of this study was to compare polytetrafluoroethylene (PTFE) grafts versus tunneled cuffed permanent catheters (TCCs) in terms of vascular access and patients' survival. An observational study was carried out with a 2-year follow-up. Eighty-seven chronic hemodialysis patients were enrolled: 31 with a PTFE graft as vascular access for hemodialysis versus 56 with a TCC. Patients' mean age was 63.8 ± 14.6 (grafts) versus 73.5 ± 11.3 years (TCCs), P = 0.001. Significantly more patients with TCC had atrial fibrillation than patients with grafts (30.3% versus 6.5%, P = 0.01). In an unadjusted Kaplan-Meier analysis, median TCC survival at 24 months was 5.4 months longer than that of PTFE grafts but not significantly (log-rank test = 1.3, P = ns). In a Cox regression analysis adjusted for age, gender, number of previous vascular accesses, diabetes, atrial fibrillation, smoking, and any complication, this lack of significant difference in survival of the vascular access between TCC and PTFE groups was confirmed and diabetes proved to be an independent risk factor for the survival of both vascular accesses considered (P = 0.02). In an unadjusted Kaplan-Meier analysis, a higher mortality was found in the TCC group than in the PTFE group at 24 months (log-rank test = 10.07, P PTFE grafts. When an arteriovenous fistula (AVF) is not possible, PTFE grafts can be considered the vascular access of second choice, whereas TCCs can be used when an AVF or PTFE graft are not feasible or as a bridge to AVF or PTFE graft creation. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  20. Plasma mediated protein immobilisation enhances the vascular compatibility of polyurethane with tissue matched mechanical properties.

    Science.gov (United States)

    Kondyurina, Irina; Wise, Steven G; Ngo, Alan K Y; Filipe, Elysse C; Kondyurin, Alexey; Weiss, Anthony S; Bao, Shisan; Bilek, Marcela M M

    2017-07-04

    Polyurethanes are a diverse class of polymers, with independently tunable mechanical and biodegradation properties making them a versatile platform material for biomedical implants. Previous iterations have failed to adequately embody appropriate mechanical and biological properties, particularly for vascular medicine where strength, compliance and multifaceted biocompatibility are required. We have synthesized a new polyurethane formulation with finely tuned mechanical properties, combining high strength and extensibility with a low Young's modulus. Additional cross-linking during synthesis enhanced stability and limits leaching. Under cyclic testing, hysteresis was minimal following completion of the initial cycles, indicating the robustness of the material. Building on this platform, we used plasma immersion ion implantation to activate the polymer surface and functionalized it with recombinant human tropoelastin. With tropoelastin covalently bound to the surface, human coronary endothelial cells showed improved attachment and proliferation. In the presence of heparinized whole blood, tropoelastin-coated polyurethane showed very low thrombogenicity in both static and flow conditions. Using this formulation, we synthesized robust, elastic prototype conduits which easily retained multiple sutures and were successfully implanted in a pilot rat aortic interposition model. We have thus created an elastic, strong biomaterial platform, functionalized with an important regulator of vascular biology, with the potential for further evaluation as a new synthetic graft material.

  1. Evidence suggests rigid aortic grafts increase systolic blood pressure: results of a preliminary study.

    Science.gov (United States)

    O'Brien, T; Morris, L; McGloughlin, T

    2008-01-01

    Abdominal aortic aneurysm (AAA) is a serious complication of the aorta and is treated using vascular bypass grafts. Two main classes of graft are available to treat AAA; grafts implanted by open surgery and stent-grafts implanted using minimally invasive endovascular techniques. Both classes of graft consist of an aortic section which bifurcates into two iliac sections. It has been hypothesized that implantation of aortic grafts and stent-grafts serve to significantly increase abdominal aortic pressures. In this study, an open-loop computer-controlled pumping system was built to produce physiologically realistic pressure and flow-rates. Models of a compliant abdominal aortic aneurysm, a compliant walled graft and a tapered graft were manufactured using an injection moulding technique and fused deposition modelling was used to create a rigid walled graft. A specific transient flow-rate waveform was then applied at the inlet of each model and the resulting pressure waveforms 30 mm upstream from the bifurcation was recorded. Peak pressure measurements were recorded over the course of the pulse for each model. The compliant aneurysm model was found to have a systolic pressure of 107 mmHg while the complaint graft model was 153 mmHg. The rigid graft model had a peak systolic pressure of 199 mmHg. In the tapered graft, the peak pressure dropped to 142 mmHg. The data suggests that implanting a graft model in place of an aneurysm model in an in vitro flow circuit can increase the pressures recorded upstream from the iliac bifurcation and that tapered grafts may alleviate this problem.

  2. Bone Graft Alternatives

    Science.gov (United States)

    ... spinal deformity, or who have some types of disc herniations. In certain types of spinal fusion, bone grafts ... Specialist SEARCH Download Brochure ENGLISH Related Treatments Cervical Disc Herniation Fusion Lumbar Disc Herniation {1} ##LOC[OK]## {1} ## ...

  3. 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.

  4. 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

  5. Our Experience on Peripheral Vascular Trauma

    Directory of Open Access Journals (Sweden)

    Funda Tor

    2012-08-01

    Full Text Available Purpose: The aim of this study was to determine etiology and management in patients with peripheral vascular trauma. Method: From May 2010 to May 2012, 48 cases who was admitted Adana Sample Education and Research Hospital Department of cardiovascular surgery with a diagnosis peripheral artery injury have been included in this study. All files of the patients have been reviewed retrospectively. Results: Upper extremity vascular trauma have been seen in 30 patients lower extremitiy vascular trauma in 18 patients too. The causes of injuries were penetrating injuries in 26 patients , gon shot injuries in 3 patients , blunt tarauma in 1 patients. . The causes of lower extremity injuries were; penetrating injuries in 5 patients , blunt trauma in 3 patients. As a surgical procedure simple repair , end to end anastomosis , venous graft or PTFE graft interposition was performed. Conclusions: Early intervention and treatment decreased the morbidity and mortality in patients with peripheral vascular injuries. [Cukurova Med J 2012; 37(4.000: 193-197

  6. PVDF multifilament yarns grafted with polystyrene induced by γ-irradiation: Influence of the grafting parameters on the mechanical properties

    International Nuclear Information System (INIS)

    Marmey, P.; Porte, M.C.; Baquey, Ch.

    2003-01-01

    The development of alternative prosthetic materials for cardiovascular applications has found growing interest due to the failure to date to be able to implement functional patent small diameter vascular grafts (diameter <5 mm). For instance, the successful implantation of small diameter polyester (PET) and expanded polytetrafluoroethylene (PTFEe) vascular grafts has not been achieved in humans. Our strategy is to work with a new multifilament yarns biomaterial, produced from polyvinylidene fluoride (PVDF), which shows suitable mechanical properties, such as a lower tensile modulus than PET and PTFEe. The required biological properties sought for (i.e. low thrombogenicity) could be achieved by 'heparin-like' surface modification treatments in order to modify the thrombogenicity levels of the polymeric materials [Ann. Biomed. Eng. 7 (1979) 429]. A four step method is necessary to achieve this 'heparin-like' surface transformation [J. Biomed. Mater. Res. 52 (2000) 119]. The first step consists in grafting polystyrene onto the PVDF surface by γ irradiation. The purpose of this study was to evaluate the influence of grafting parameters on the mechanical properties: (i) γ-ray irradiation time and (ii) grafting time of styrene monomers, which polymerize and form polystyrene bound to the PVDF surface

  7. Missed Vascular Injuries: Presentation and Outcome

    International Nuclear Information System (INIS)

    Siddique, M. K.; Majeed, S.; Ahmad, N.; Irfan, M.

    2014-01-01

    Objective: To describe the different presentation, diagnostic evaluation, management and outcome of complications of missed vascular injuries. Study Design: A case series. Place and Duration of Study: Combined Military Hospital, Rawalpindi and Combined Military Hospital, Kharian Cantt, from June 2009 to June 2012. Methodology: All the patients with vascular injuries missed at the time of causative trauma who reported during this study period were included. Patients presented with acute vascular injuries and iatrogenic aneurysm at the vascular anastomosis site were excluded. All cases were evaluated with either CT or conventional angiography and managed with various open vascular surgical techniques and their results were assessed. Results: Twenty eight patients with missed vascular injury underwent various vascular repairs. Age of patients ranged from 16 to 78 years (mean = 33.7 A +- 15.4 years). Male to female ratio was 6:1. Twelve (42.8%) patients presented with pseudoaneurysm alone, 10 (35.7%) with traumatic arteriovenous fistulae, 4 (14.3%) with post-traumatic thrombosis and occlusion and 2 (7.1%) with pseudoaneurysm and hemorrhage. Penetrating injuries were the commonest cause in 19 (67.8%). The time interval between injury and presentation in hospital ranged from 2 to 1300 weeks (mean 228 weeks). Lower limb vessels were affected in 20 (71.4%), the upper limb in 5 (17.8%) and neck vessels in 3 (10.7%). Superficial femoral artery was the most frequently involved artery in 9 (32.1%) cases. Interposition reverse autogenous saphenous vein graft was most common type of repair in all types of missed vascular injuries. One (3.5%) patient had amputation after secondary hemorrhage. Conclusion: Low velocity penetrating trauma was the common cause of missed vascular injury. Pseudoaneurysm was the most common presentation. (author)

  8. Constructing a blood vessel on the porous scaffold modified with vascular endothelial growth factor and basic fibroblast growth factor

    Science.gov (United States)

    Sevostyanova, V. V.; Matveeva, V. G.; Antonova, L. V.; Velikanova, E. A.; Shabaev, A. R.; Senokosova, E. A.; Krivkina, E. O.; Vasyukov, G. Yu.; Glushkova, T. V.; Kudryavtseva, Yu. A.; Barbarash, O. L.; Barbarash, L. S.

    2016-11-01

    Incorporation of the growth factors into biodegradable polymers is a promising approach for the fabrication of tissue-engineered vascular grafts. Here we blended poly(ɛ-caprolactone) (PCL) with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) following incorporation of either vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF) and then fabricated electrospun 2 mm diameter vascular grafts. Grafts without the growth factors were used as a control group. Structure of the grafts was assessed utilizing scanning electron microscopy. We further implanted our grafts into rat abdominal aorta for 1 and 3 months with the aim to test endothelialization, cell infiltration, and patency in vivo. Histological and immunofluorescence examination demonstrated enhanced endothelialization and cell infiltration of the grafts with either VEGF or bFGF compared to those without the growth factors. Grafts with VEGF showed higher patency compared to those with bFGF; however, bFGF promoted migration of smooth muscle cells and fibroblasts into the graft. Therefore, we conclude that incorporation of VEGF and bFGF into the inner and medial/outer layer, respectively, can be a promising option for the fabrication of tissue-engineered vascular grafts.

  9. 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.

  10. 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....

  11. 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 ...

  12. Principles of management of vascular problems in the diabetic foot

    African Journals Online (AJOL)

    The treatment of vascular insufficiency either by bypass grafting or endovascular ... evidence, however, that diabetes mellitus increases perioperative cardiac morbidity or ... endovascular treatment of the neuroischaemic diabetic foot and heads the multidisciplinary foot clinics at Montana and Wilgers hospitals in Pretoria.

  13. Convenient synthetic method of starch/lactic acid graft copolymer ...

    Indian Academy of Sciences (India)

    is a potentially useful and completely biodegradable material for biodegradable plastics because of its nontoxic, low cost and its natural abundance which can be obtained from many crops including corn, wheat, rice, potato and so on (Tester and Karkallas 2002). Therefore, modification of starch, physi- cally and chemically ...

  14. Convenient synthetic method of starch/lactic acid graft copolymer ...

    Indian Academy of Sciences (India)

    Cho and Lee 2002; Zhai et al 2002; Fanta et al 2004) can improve the ... aliphatic polyester (Sang et al 1997; Choi et al 1999; Dubois et al 1999) are a .... Chemical shift /ppm. 5.50. 5.40 4.59. 3.60~3.40. (A). DMSO. Figure 4. 1H-NMR spectra of cornstarch (A) and starch/LA copolymer (B). HO. OH. CH3. O. O. H. O. HO. H. OH.

  15. VASCULAR INJURIES IN TEHRAN: A REVIEW OF 123 CASES

    Directory of Open Access Journals (Sweden)

    M. Karbakhsh M. R. Zarei

    2006-09-01

    Full Text Available Abstract- Studies of the epidemiology of civilian vascular trauma in developing countries are rather few. This is a prospective study of our experience with vascular trauma in a referral university hospital in Tehran, Iran. The aim was to study the etiology, pattern of injuries and the mortality and morbidity rates due to vascular trauma in our population. In this cross-sectional study, all trauma patients suspicious of having vascular injuries who were admitted to Sina Hospital between March 2002 and May 2003 were included. Among 123 studied cases, there were 109 males and 14 females.Blunt injuries were more common than penetrating ones (56.1% vs. 43.9%. The most common anatomical site of vascular injuries had been knee and lower leg. In fact, cases with lower extremities vascular trauma were twice as common as those with vascular trauma in upper limbs (59.1% vs. 27.3%. The commonest injured vessels were popliteal artery followed by femoral artery. Arterial repair with graft interposition was done in 23 cases and bypass graft in 13 cases. Procedures on veins were performed in 24 cases. Five patients (4.06% died and in 3 cases the patients died because of non-vascular reasons. The present study allows an understanding of the epidemiology of vascular trauma in the one of the major trauma centers in the metropolitan city of Tehran. The majority of our cases were young males sustaining vascular injuries due to road traffic accidents or being stabbed with knives. It also has important implications for vascular injury prevention in our community.

  16. 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.

  17. Axillobifemoral bypass grafting

    Directory of Open Access Journals (Sweden)

    Davidović Lazar B.

    2004-01-01

    Full Text Available INTRODUCTION Axillo-femoral bypass (AxF means connecting the axillar and femoral artery with the graft that is placed subcutaneously [1]. Usually, this graft is connected with contralateral femoral artery via one accessory subcutaneous graft, and this connection is known as axillobifemoral bypass (AxFF. This extra-anatomic procedure is an alternative method to the standard reconstruction of aortoiliac region when there are contraindications for general or local reasons. OBJECTIVE The objective of this paper is to show early and late results of AxFF bypass grafting as well as to show the indications for AxFF bypass. METHODS The sample consisted of 37 patients. The procedure was performed in 28 patients who suffered from aortoiliac occlusive disease and who were at high risk due to the comorbidity- in one patient with the rupture of juxtarenal aneurysm of abdominal aorta; in five patients with aortoenteric fistula, in two patients with iatrogenic lesion of abdominal aorta and in one female patient with anus preternaturalis definitivus who was treated for rectovaginal fistula. Donor's right axillary artery was used in 26 cases (70.3%, and donor's left axillary artery was used in 9 cases (29.7%. Dacron graft was used in 34 patients and Polytetrafluo-roethlylene graft was used in three patients. Simultaneously, profundo-plastic was done in four patients and femoro-popliteal bypass was performed in three patients. In five patients who suffered from aortoenteric fistula, simultaneous intervention of gastrointerstinal system has been done, x2 test was used for statistical evaluation and life table method was used for verification of late graft patency. RESULTS The rate of early postoperative mortality was 13.5%. The causes of death were: sepsis -1, MOFS - 3, and infarct myocardium -1. The mean follow up period was 40.1 months, ranging from six months to 17 years. During the follow up period, an early graft thrombosis was identified in two and late graft

  18. Complications of grafts used in female pelvic floor reconstruction: Mesh erosion and extrusion

    Directory of Open Access Journals (Sweden)

    Tanya M Nazemi

    2007-01-01

    Full Text Available Introduction: Various grafts have been used in the treatment of urinary incontinence and pelvic prolapse. Autologous materials such as muscle and fascia were first utilized to provide additional anatomic support to the periurethral and pelvic tissues; however, attempts to minimize the invasiveness of the procedures have led to the use of synthetic materials. Complications such as infection and erosion or extrusion associated with these materials may be troublesome to manage. We review the literature and describe a brief overview of grafts used in pelvic floor reconstruction and focus on the management complications specifically related to synthetic materials. Materials and Methods: We performed a comprehensive review of the literature on grafts used in pelvic floor surgery using MEDLINE and resources cited in those peer-reviewed manuscripts. The results are presented. Results: Biologic materials provide adequate cure rates but have associated downfalls including potential complications from harvesting, variable tissue quality and cost. The use of synthetic materials as an alternative graft in pelvic floor repairs has become a popular option. Of all synthetic materials, the type I macroporous polypropylene meshes have demonstrated superiority in terms of efficacy and fewer complication rates due to their structure and composition. Erosion and extrusion of mesh are common and troublesome complications that may be managed conservatively with observation with or without local hormone therapy, with transvaginal debridement or with surgical exploration and total mesh excision, dependent upon the location of the mesh and the mesh type utilized. Conclusions: The ideal graft would provide structural integrity and durability with minimal adverse reaction by the host tissue. Biologic materials in general tend to have fewer associated complications, however, the risks of harvesting, variable integrity of allografts, availability and high cost has led to the

  19. Intraarterial 9-beta-methyl carbacyclin improves canine polytetrafluoroethylene graft patency

    International Nuclear Information System (INIS)

    Dacey, L.J.; Hees, P.S.; Cronenwett, J.L.

    1988-01-01

    This study examined the effect of 9-beta-methyl carbacyclin, a synthetic, stable prostacyclin analog, on canine polytetrafluoroethylene (PTFE) graft patency. Twenty-five dogs had 4 mm x 7 cm PTFE grafts implanted bilaterally into the femoral arteries. A subcutaneous infusion pump was used to deliver either saline solution (control) or 9-beta-methyl carbacyclin (Ciprostine) at 100 (CARB-100) or 200 ng/kg/min (CARB-200) through a femoral artery branch just proximal to one of the femoral grafts, with the contralateral graft serving as a noninfused control. Graft-platelet deposition (with 111 In-labeled platelets) was measured between the fifth and seventh days, with patency determined on the seventh day. Dogs were classified as aggregators (AGG [+]) if the preoperative epinephrine-enhanced sodium arachidonate platelet aggregation was greater than 20%. CARB-200 infusion significantly improved ipsilateral graft patency (80%) compared with noninfused grafts (50%, p less than 0.05), or grafts in control and CARB-100 dogs (43%, p less than 0.05). Anastomotic platelet deposition was decreased bilaterally in CARB-200 dogs by 45% to 59% compared with CARB-100 and control dogs (p less than 0.05). With the exception of grafts infused with CARB-200, AGG (+) dogs had significantly lower graft patency (26%) than nonaggregator AGG (-) dogs (71%, p less than 0.01). CARB-200 infusion significantly improved graft patency in AGG (+) dogs (71%), compared with control and CARB-100-infused grafts (19%, p less than 0.025). Intra-arterial 9-beta-methyl carbacyclin improved early PTFE graft patency and inhibited platelet deposition in a severe canine model, independent of baseline platelet aggregation status, which also had an important effect on graft patency

  20. Graft polymerization of vinyl acetate onto starch. Saponification to starch-g-poly(vinyl alcohol)

    International Nuclear Information System (INIS)

    Fanta, G.F.; Burr, R.C.; Doane, W.M.; Russell, C.R.

    1979-01-01

    Graft polymerizations of vinyl acetate onto granular cornstarch were initiated by cobalt-60 irradiation of starch-monomer-water mixtures, and ungrafted poly(vinyl acetate) was separated from the graft copolymer by benzene extraction. Conversions of monomer to polymer were quantitative at a radiation dose of 1.0 Mrad. Over half of the polymer was present as ungrafted poly(vinyl acetate) (grafting efficiency less than 50%), and the graft copolymer contained only 34% grafted synthetic polymer (34% add-on). Lower irradiation doses produced lower conversions of monomer to polymer and gave graft copolymers with lower % add-on. Addition of minor amounts of acrylamide, methyl acrylate, and methacrylic acid as comonomers produced only small increases in % add-on and grafting efficency. Grafting efficiency was increased to 70% when a monomer mixture containing about 10% methyl methacrylate was used. Grafting efficiency could be increased to over 90% if the graft polymerization of vinyl acetate--methyl methacrylate was carried out near 0 0 C; although conversion of monomers to polymer was low and grafted polymer contained 40 to 50% poly(methyl methacrylate). Selected graft copolymers were treated with methanolic sodium hydroxide to convert starch-g-poly(vinyl acetate) to starch-g-poly(vinyl alcohol). The molecular weight of the poly(vinyl alcohol) moiety was about 30,000. The solubility of starch-g-poly(vinyl alcohol) in hot water was less than 50; however, solubility could be increased by substituting either acid-modified or hypochlorite-oxidized for unmodified starch in the graft polymerization reaction. Vinyl acetate was also graft polymerized onto acid-modified starch which had been dispersed and partially solubilized by heating in water. A total irradiation dose of either 1.0 or 0.5 Mrad gave starch-g-poly

  1. Grafts for Ridge Preservation

    Science.gov (United States)

    Jamjoom, Amal; Cohen, Robert E.

    2015-01-01

    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. PMID:26262646

  2. [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.

  3. 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.

  4. Arteriovenous shunt graft ulceration with sinus and graft epithelialization

    Directory of Open Access Journals (Sweden)

    Pooja Singhal

    2015-03-01

    Full Text Available Arteriovenous fistula and grafts are used as access sites for patients with chronic kidney disease and are prone for complications. Stent grafts are used to treat access site complications. We report a rare and unusual finding of epithelialization of the sinus tract and the lumen of a polytetrafluoroethylene graft, following ulceration of the overlying skin.

  5. Anatomical reference point for harvesting a flexor graft during arthroscopic reconstruction of the anterior cruciate ligament

    Directory of Open Access Journals (Sweden)

    Clécio de Lima Lopes

    2015-04-01

    Full Text Available OBJECTIVES: To evaluate the prevalence of a vascular network adjacent to the insertion of the pes anserinus, so that it could be used as an anatomical reference point to facilitate harvesting flexor grafts for arthroscopic reconstruction of the anterior cruciate ligament (ACL.METHODS: Thirty patients with ACL tears who were going to undergo ACL reconstruction using the tendons of the semitendinosus and gracilis muscles as grafts were selected randomly. During the harvesting of these tendons, the presence or absence of this anatomical reference point was noted.RESULTS: All the patients presented a vascular network of greater or lesser diameter.CONCLUSION: The vascular network seems to be a good reference point during harvesting of the tendons of the semitendinosus and gracilis muscles, for facilitating graft harvesting.

  6. Angiopoietin 2 alters pancreatic vascularization in diabetic conditions.

    Directory of Open Access Journals (Sweden)

    Sophie Calderari

    Full Text Available AIMS/HYPOTHESIS: Islet vascularization, by controlling beta-cell mass expansion in response to increased insulin demand, is implicated in the progression to glucose intolerance and type 2 diabetes. We investigated how hyperglycaemia impairs expansion and differentiation of the growing pancreas. We have grafted xenogenic (avian embryonic pancreas in severe combined immuno-deficient (SCID mouse and analyzed endocrine and endothelial development in hyperglycaemic compared to normoglycaemic conditions. METHODS: 14 dpi chicken pancreases were grafted under the kidney capsule of normoglycaemic or hyperglycaemic, streptozotocin-induced, SCID mice and analyzed two weeks later. Vascularization was analyzed both quantitatively and qualitatively using either in situ hybridization with both mouse- and chick-specific RNA probes for VEGFR2 or immunohistochemistry with an antibody to nestin, a marker of endothelial cells that is specific for murine cells. To inhibit angiopoietin 2 (Ang2, SCID mice were treated with 4 mg/kg IP L1-10 twice/week. RESULTS: In normoglycaemic condition, chicken-derived endocrine and exocrine cells developed well and intragraft vessels were lined with mouse endothelial cells. When pancreases were grafted in hyperglycaemic mice, growth and differentiation of the graft were altered and we observed endothelial discontinuities, large blood-filled spaces. Vessel density was decreased. These major vascular anomalies were associated with strong over-expression of chick-Ang2. To explore the possibility that Ang2 over-expression could be a key step in vascular disorganization induced by hyperglycaemia, we treated mice with L1-10, an Ang-2 specific inhibitor. Inhibition of Ang2 improved vascularization and beta-cell density. CONCLUSIONS: This work highlighted an important role of Ang2 in pancreatic vascular defects induced by hyperglycaemia.

  7. 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.

  8. Cells adhesion and growth on gold nanoparticle grafted glass

    Energy Technology Data Exchange (ETDEWEB)

    Novotna, Zdenka, E-mail: zdenka1.novotna@vscht.cz [Department of Solid State Engineering, Institute of Chemical Technology Prague, 166 28 Prague (Czech Republic); Reznickova, Alena; Kvitek, Ondrej; Kasalkova, Nikola Slepickova [Department of Solid State Engineering, Institute of Chemical Technology Prague, 166 28 Prague (Czech Republic); Kolska, Zdenka [Faculty of Science, J. E. Purkyně University, Ústí nad Labem (Czech Republic); Svorcik, Vaclav [Department of Solid State Engineering, Institute of Chemical Technology Prague, 166 28 Prague (Czech Republic)

    2014-07-01

    The surface of glass substrate was plasma treated, coated by gold nano-structures and subsequently grafted with nanoparticles. The samples were plasma treated, sputtered with Au nanostructures which was followed by grafting with biphenyl-4,4'-dithiol (BPD) and then gold nanoparticles. The wettability, optical and chemical properties and surface morphology were studied. The adhesion and proliferation of vascular smooth muscle cells (VSMCs) on the samples were investigated in-vitro as well. Grafting of gold nanoparticles with the dithiol increases the UV–vis absorbance, the surface becomes more hydrophobic, rougher and more rugged compared to pristine, sputtered and only dithiol treated surface. Gold nano-particles bound over dithiol and Au nanostructures cause better cell proliferation than purely BPD treated or pristine glass.

  9. Graft nephrectomy: The SGPGI experience

    OpenAIRE

    Nand Kishore Arvind; Aneesh Srivastava; Anant Kumar; Subodh K Das

    2002-01-01

    Background: Graft nephrectomy is often considered a hazardous procedure with high morbidity and occasional mortality, and this may pose a technical challenge. The aim of this study was to evaluate the indications, etiology and complications following graft nephrectomy. Materials and Methods: From 1988 to 2001, among total of 1,019 live related renal transplants carried at our center, 46 underwent graft nephrectomy. Patients were divided into 2 groups depending on timing of graft re-mova...

  10. Haemodynamics in axillobifemoral bypass grafts

    NARCIS (Netherlands)

    C.H. Wittens

    1992-01-01

    textabstractThis thesis is based on four publications on the subject of graft configuration and haemodynamics in axillobifemoral bypass grafts: 1. A clinical evaluation of 17 patients with axillobifemoral bypass graft operations, performed for various indications. Two important observations were

  11. A study of the behaviour of irradiated or unirradiated grafts in the camera aquosa of irradiated and unirradiated animals

    International Nuclear Information System (INIS)

    Djalali-Behzad, G.

    1969-06-01

    Following grafts of new born mice spinal ganglia in the 'camera aquosa' of adult mice, the authors tried hematopoietic tissue grafts in the same conditions. The growth of iso-logous and hetero-logous bone marrow in the 'camera aquosa' showed that this tissue, even after exposure to supralethal doses, was capable of survival and growth. A counter-experiment with non irradiated bone marrow grafts in the 'camera aquosa' of rats delivered 700 rads led to the conclusion that the environment, intoxicated by exposure, acted on the graft so that after vascularization it became unable to grow. (author) [fr

  12. Stent expansion of stretch Gore-Tex grafts in children with congenital heart lesions.

    Science.gov (United States)

    Brown, Stephen C; Boshoff, Derize E; Heying, Ruth; Gorenflo, Matthias; Rega, Filip; Eyskens, Benedicte; Meyns, Bart; Gewillig, Marc

    2010-05-01

    To evaluate the efficacy and safety of expanding vascular shunt grafts beyond original nominal diameter using stents. Bench testing confirmed the expandability of 3.5 mm and 4.0 mm vascular Gore-Tex stretch grafts. A retrospective analysis included eleven systemic to pulmonary artery shunts with diminished flow which were stented with the aim of increasing the original nominal diameter of the shunts. During bench testing, the grafts could be expanded to 4.5 mm and 5.8 mm, respectively. Fourteen stents were implanted in 11 stretch grafts a median of 18.9 months (3.2; 21.6 months) after shunt surgery. There was a median increase in diameter of 1.4 mm (0.9; 1.7 mm) [P = 0.001, 95% CI: 0.47; 1.7) from original nominal to final stented diameter of the shunts with a median gain of 28%. A simultaneous improvement in saturations from a median of 73% (66; 77%) to 87% (84; 89%) [P = 0.015; 95% CI: 3; 22] was observed. No complications were experienced during the procedures. In our limited experience, stretch Gore-Tex vascular grafts can be safely expanded beyond nominal diameters using high pressure vascular stents. This leads to improvement in saturation and pulmonary blood flow. It allows the clinician to tailor pulmonary flow in relation to pulmonary artery size and growth, ensuring best possible timing for the next surgical procedure. Copyright 2010 Wiley-Liss, Inc.

  13. Acrylonitrile grafted to PVDF

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Bone graft in the treatment of nonunion of the scaphoid with necrosis of the proximal pole: a literature review

    Directory of Open Access Journals (Sweden)

    Antônio Lourenço Severo

    Full Text Available ABSTRACT 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.

  15. 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.

  16. Assessment of Bonelike (registered) graft with a resorbable matrix using an animal model

    International Nuclear Information System (INIS)

    Lobato, J.V.; Hussain, N. Sooraj; Botelho, C.M.; Mauricio, A.C.; Afonso, A.; Ali, N.; Santos, J.D.

    2006-01-01

    Synthetic bone grafts have been developed to provide an alternative to autografts and allografts. Bonelike (registered) is a patented synthetic osteoconductive bone graft that mimics the mineral composition of natural bone. In the present preliminary animal studies a user-friendly version of synthetic bone graft Bonelike (registered) have been developed by using a resorbable matrix, Floseal (registered) , as a vehicle and raloxifene hydrochloride as a therapeutic molecule, that is known to decrease osteoclast activity and therefore enhanced bone formation. From histological and scanning electron microscopy evaluations, the use of Bonelike (registered) associated with Floseal (registered) and raloxifene hydrochloride showed that new bone was rapidly apposed on implanted granules and also that the presence of the matrix and therapeutic molecule does not alter the proven highly osteoconductivity properties of Bonelike (registered) . Therefore, this association may be one step-forward for the clinical applications of Bonelike (registered) scaffolds since it is much more easy-to-handle when compared to granular materials

  17. Polysulfone Functionalized With Phosphonated Poly(pentafluorostyrene) Grafts for Potential Fuel Cell Applications

    DEFF Research Database (Denmark)

    Dimitrov, Ivaylo; Takamuku, Shogo; Jankova Atanasova, Katja

    2012-01-01

    A multi‐step synthetic strategy to polysulfone (PSU) grafted with phosphonated poly(pentafluorostyrene) (PFS) is developed. It involves controlled radical polymerization resulting in alkyne‐end functional PFS. The next step is the modification of PSU with a number of azide side groups. The grafti....... The proposed synthetic route opens the possibility to tune copolymers’ hydrophilic–hydrophobic balance to obtain membranes with an optimal balance between proton conductivity and mechanical properties.......A multi‐step synthetic strategy to polysulfone (PSU) grafted with phosphonated poly(pentafluorostyrene) (PFS) is developed. It involves controlled radical polymerization resulting in alkyne‐end functional PFS. The next step is the modification of PSU with a number of azide side groups. The grafting...

  18. Effect of a selective thromboxane synthase inhibitor on arterial graft patency and platelet deposition in dogs

    International Nuclear Information System (INIS)

    McDaniel, M.D.; Huntsman, W.T.; Miett, T.O.; Cronenwett, J.L.

    1987-01-01

    This study examined the effect of selective thromboxane synthase inhibition and nonselective cyclooxygenase inhibition on vascular graft patency and indium 111-labeled platelet deposition in 35 mongrel dogs undergoing carotid artery replacement with 4 mm X 4 cm polytetrafluoroethylene (PTFE) (one side) and Dacron (opposite side) end-to-end grafts. Aspirin-dipyridamole therapy improved one-week graft patency, from 46% in untreated dogs to 93% in treated dogs. Thromboxane synthase inhibition (U-63557A) improved graft patency in these dogs to 81%. Both drug treatments reduced platelet deposition on Dacron and PTFE grafts by 48% to 68% compared with control dogs. Dacron grafts accumulated significantly more platelets than PTFE grafts but had comparable patency rates. Low-dose aspirin therapy had no significant effect on either graft patency or platelet deposition. All treatment groups showed a 60% to 76% reduction in serum thromboxane B2, but only thromboxane synthase inhibitor treatment increased plasma 6-keto-prostaglandin F1 alpha by 100%. Selective thromboxane synthase inhibition improved small-caliber prosthetic graft patency to the same extent as did conventional cyclooxygenase inhibition in this preliminary study

  19. Detection of imminent vein graft occlusion: what is the optimal surveillance program?

    Science.gov (United States)

    Tinder, Chelsey N; Bandyk, Dennis F

    2009-12-01

    The prediction of infrainguinal vein bypass failure remains an inexact judgment. Patient demographics, technical factors, and vascular laboratory graft surveillance testing are helpful in identifying a high-risk graft cohort. The optimal surveillance program to detect the bypass at risk for imminent occlusion continues to be developed, but required elements are known and include clinical assessment for new or changes in limb ischemia symptoms, measurement of ankle and/or toe systolic pressure, and duplex ultrasound imaging of the bypass graft. Duplex ultrasound assessment of bypass hemodynamics may be the most accurate method to detect imminent vein graft occlusion. The finding of low graft flow during intraoperative assessment or at a scheduled surveillance study predicts failure; and if associated with an occlusive lesion, a graft revision can prolong patency. The most common abnormality producing graft failure is conduit stenosis caused by myointimal hyperplasia; and the majority can be repaired by an endovascular intervention. Frequency of testing to detect the failing bypass should be individualized to the patient, the type of arterial bypass, and prior duplex ultrasound scan findings. The focus of surveillance is on identification of the low-flow arterial bypass and timely repair of detected critical stenosis defined by duplex velocity spectra criteria of a peak systolic velocity 300 cm/s and peak systolic velocity ratio across the stenosis >3.5-correlating with >70% diameter-reducing stenosis. When conducted appropriately, a graft surveillance program should result in an unexpected graft failure rate of <3% per year.

  20. Less Than Total Excision of Infected Prosthetic PTFE Graft Does Not Increase the Risk of Reinfection.

    Science.gov (United States)

    Sgroi, Michael D; Kirkpatrick, Vincent E; Resnick, Karen A; Williams, Russell A; Wilson, Samuel E; Gordon, Ian L

    2015-01-01

    Traditional treatment of infected polytetrafluoroethylene (PTFE) grafts consist of removal of the entire prosthesis. Closure of the native vessels may compromise vascular patency. We examined the outcomes for patients in whom a PTFE remnant of an infected graft was retained on the vessel. We reviewed the operating room log from 2000 to 2011 and identified all patients who had partial removal of an infected PTFE graft used for hemodialysis or peripheral bypass. These patients were examined for subsequent complications. Twenty-seven patients underwent 30 partial graft excisions with mean follow-up of 27 months. A total of 17% (5 of 30) of the partial graft resection procedures resulted in complications. Of 48 total remnants left behind at the arterial or venous anastomoses, reinfection occurred in 15%. Leaving a well-incorporated small 1-to 5-mm PTFE remnant at the arterial or venous anastomoses can be performed safely with a low risk of complications. © The Author(s) 2015.

  1. 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.

  2. Reconstruction of mandibular defects with autogenous bone grafts: a review of 30 cases

    International Nuclear Information System (INIS)

    Sajid, M.A.; Warraich, R.A.; Abid, H.; Haq, M.E.; Shah, K.L.; Khan, Z.

    2012-01-01

    Multitudes of options are available for reconstruction of functional and cosmetic defects of the mandible, caused by various ailments. At the present time, autogenous bone grafting is the gold standard by which all other techniques of reconstruction of the mandible can be judged. The purpose of this study was to evaluate the outcome of different osseous reconstruction options using autogenous bone grafts for mandibular reconstruction. Methods: This Interventional study was conducted at Department of Oral and Maxillofacial Surgery, King Edward Medical University/Mayo Hospital Lahore, from January 2008 to July 2009 including one year follow-up. The study was carried out on thirty patients having bony mandibular defects. They were reconstructed with the autogenous bone grafts from different graft donor sites. On post-operative visits they were evaluated for outcome variables. Results: Success rate of autogenous bone grafts in this study was 90%. Only 10% of the cases showed poor results regarding infection, resorption and graft failure. Conclusion: Autogenous bone grafts, non-vascularized or vascularized, are a reliable treatment modality for the reconstruction of the bony mandibular defects with predictable functional and aesthetic outcome. (author)

  3. Collagen vascular disease

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001223.htm Collagen vascular disease To use the sharing features on ... were previously said to have "connective tissue" or "collagen vascular" disease. We now have names for many ...

  4. Vascular Anomalies in Pediatrics.

    Science.gov (United States)

    Foley, Lisa S; Kulungowski, Ann M

    2015-08-01

    A standardized classification system allows improvements in diagnostic accuracy. Multidisciplinary vascular anomaly centers combine medical, surgical, radiologic, and pathologic expertise. This collaborative approach tailors treatment and management of vascular anomalies for affected individuals.

  5. Peripheral Vascular Disease

    Science.gov (United States)

    ... Topics FAQs Peripheral Vascular Disease Peripheral vascular disease (PVD) involves damage to or blockage in the blood ... the organs in and below your stomach area. PVD may also affect the arteries leading to your ...

  6. Plant synthetic biology.

    Science.gov (United States)

    Liu, Wusheng; Stewart, C Neal

    2015-05-01

    Plant synthetic biology is an emerging field that combines engineering principles with plant biology toward the design and production of new devices. This emerging field should play an important role in future agriculture for traditional crop improvement, but also in enabling novel bioproduction in plants. In this review we discuss the design cycles of synthetic biology as well as key engineering principles, genetic parts, and computational tools that can be utilized in plant synthetic biology. Some pioneering examples are offered as a demonstration of how synthetic biology can be used to modify plants for specific purposes. These include synthetic sensors, synthetic metabolic pathways, and synthetic genomes. We also speculate about the future of synthetic biology of plants. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Intimal hyperplasia and wall shear in arterial bypass graft distal anastomoses: an in vivo model study.

    Science.gov (United States)

    Keynton, R S; Evancho, M M; Sims, R L; Rodway, N V; Gobin, A; Rittgers, S E

    2001-10-01

    The observation of intimal hyperplasia at bypass graft anastomoses has suggested a potential interaction between local hemodynamics and vascular wall response. Wall shear has been particularly implicated because of its known effects upon the endothelium of normal vessels and, thus, was examined as to its possible role in the development of intimal hyperplasia in arterial bypass graft distal anastomoses. Tapered (4-7 mm I.D.) e-PTFE synthetic grafts 6 cm long were placed as bilateral carotid artery bypasses in six adult, mongrel dogs weighing between 25 and 30 kg with distal anastomotic graft-to-artery diameter ratios (DR) of either 1.0 or 1.5. Immediately following implantation, simultaneous axial velocity measurements were made in the toe and artery floor regions in the plane of the anastomosis at radial increments of 0.35 mm, 0.70 mm, and 1.05 mm using a specially designed 20 MHz triple crystal ultrasonic wall shear rate transducer Mean, peak, and pulse amplitude wall shear rates (WSRs), their absolute values, the spatial and temporal wall shear stress gradients (WSSG), and the oscillatory shear index (OSI) were computed from these velocity measurements. All grafts were harvested after 12 weeks implantation and measurements of the degree of intimal hyperplasia (IH) were made along the toe region and the artery floor of the host artery in 1 mm increments. While some IH occurred along the toe region (8.35+/-23.1 microm) and was significantly different between DR groups (p<0.003), the greatest amount occurred along the artery floor (81.6+/-106.5 microm, mean +/- S.D.) (p < 0.001) although no significant differences were found between DR groups. Linear regressions were performed on the paired IH and mean, peak, and pulse amplitude WSR data as well as the absolute mean, peak, and pulse amplitude WSR data from all grafts. The mean and absolute mean WSRs showed a modest correlation with IH (r = -0.406 and -0.370, respectively) with further improvements seen (r = -0

  8. The effect of platelet-rich plasma on composite graft survival.

    Science.gov (United States)

    Jeon, Yeo Reum; Kang, Eun Hye; Yang, Chae Eun; Yun, In Sik; Lee, Won Jai; Lew, Dae Hyun

    2014-08-01

    Composite grafts are suitable for facial reconstruction because of good color matching, low donor-site morbidity, acceptable texture, and easy surgical techniques. However, their use is limited to small defects and by unpredictable survival rates. As platelet-rich plasma contains large numbers of growth factors and has been widely used for tissue regeneration, this study aimed to investigate platelet-rich plasma as an adjuvant to enhance composite graft survival. Twenty New Zealand White rabbits were used, and chondrocutaneous composite grafts were applied to their ears. The grafts were then returned to their original positions after rotation to block the original circulation from the base of the graft. Each of the individual ears was assigned randomly into one of two groups: experimental (n=20; platelet-rich plasma group) or control (n=20; control group). The surrounding skin of the composite graft was injected with either 1.0 ml of platelet-rich plasma derived from autologous whole blood in the platelet-rich plasma group or normal saline in the control group. Graft survival, cutaneous blood flow, CD31-stained vessels, and vascular endothelial growth factor protein levels were examined. Twelve days after surgery, graft viability in the platelet-rich plasma group was higher than in the control group. Blood perfusion was also higher in the platelet-rich plasma group. Compared with the control group, the number of CD31 blood vessels and vascular endothelial growth factor expression levels were significantly increased in the platelet-rich plasma group. The authors' results suggest that platelet-rich plasma restores the perfusion of composite grafts by enhancing revascularization and may exert therapeutic effects on the survival of composite grafts.

  9. Research work of radiation induced graft polymerization for synthesis and modification of polymer materials in CRICI

    Energy Technology Data Exchange (ETDEWEB)

    Hu Fumin; Ma Xueming [Chenguan Research Institute of Chemical Industry, Chengdu (China)

    2000-03-01

    The direct and post radiation induced graft polymerization had been studied in CRICI (Chenguan Research Institute of Chemical Industry). The method consists of irradiation of various polymer substrates in the presence (or absence) of monomers in a liquid, saturated vapour or gaseous and non-saturated vapour. 1. Grafting of functional monomers. --- It is possible to divide the grafting into two main approaches for synthesis of functional polymer materials. The first is grafting of monomers attached required functional group such as unsaturated carboxylic acid (acrylic and methacrylic acid), unsaturated nitrogen containing (alkali) base (vinylpyridine), monomers with hydrophilic unionized and polar groups (acrylamide, N-vinylpyrrolidone glycidylmethacrylate) and so on. The second is grafting of monomers capable of continuing chemical modification after graft polymerization. This approach essentially expands synthetic possibility of RGP for preparing functional polymers. 2. The effect of some salts on aqueous solution graft polymerization. The grafting of AA or AAm onto PE by direct or post radiation method in the presence of Mohr's salt or cupric nitrate was studied in detail. 3. Radiation induced graft polymerization by gaseous phase of monomers. This method consists of irradiation or preirradiation of various polymer substrates in the presence (or absence for preirradiation) of monomer in a gaseous of nonsaturated vapour state. (J.P.N.)

  10. Synthetic antifreeze peptide

    OpenAIRE

    1991-01-01

    A synthetic antifreeze peptide and a synthetic gene coding for the antifreeze peptide have been produced. The antifreeze peptide has a greater number of repeating amino acid sequences than is present in the native antifreeze peptides from winter flounder upon which the synthetic antifreeze peptide was modeled. Each repeating amino acid sequence has two polar amino acid residues which are spaced a controlled distance apart so that the antifreeze peptide may inhibit ice formation. The synthetic...

  11. 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.

  12. [SYNTHETIC PEPTIDE VACCINES].

    Science.gov (United States)

    Sergeyev, O V; Barinsky, I F

    2016-01-01

    An update on the development and trials of synthetic peptide vaccines is reviewed. The review considers the successful examples of specific protection as a result of immunization with synthetic peptides using various protocols. The importance of conformation for the immunogenicity of the peptide is pointed out. An alternative strategy of the protection of the organism against the infection using synthetic peptides is suggested.

  13. Post-transplant urological and vascular complications

    Directory of Open Access Journals (Sweden)

    Safa Javid

    2009-01-01

    Full Text Available To determine the prevalence of urological and vascular complications in renal trans-plant recipients (RTx at Tabriz Renal Transplant Center, we studied 55 recipients of renal allo-grafts (25 male and 29 female patients with a mean age of 38.3 ± 13.4 years from October 2005 to November 2006. The surgical complications in our study included hematomas: 20.4%, renal artery stenosis: 20.4%, calculi: 7.4%, hydronephrosis or ureteral stricture: 5.6%, urinary leakage: 5.6%, lymphoceles: 1.9%, and renal vein thrombosis: 1.9%. We conclude that the most common urologic complications in our center were ureteric strictures and urine leaks, and the most common vascular complication was renal artery stenosis.

  14. Periorbital fat grafting.

    Science.gov (United States)

    Massry, Guy G; Azizzadeh, Babak

    2013-02-01

    Periorbital aging is a multifactorial process involving volume loss (bone and soft tissue), tissue decent, and cutaneous degenerative changes. Traditional approaches to surgery on this area of the face have been subtractive in nature, focusing on excision of skin, muscle, and fat. This has frequently led to a gaunt or hollowed postoperative appearance. Contemporary aesthetic eyelid and periorbital rejuvenation has undergone a paradigm shift from an excisionally based surgical approach to one that prioritizes volume preservation and/or augmentation. The development of fat grafting to the eyelids and periorbita has given the eyelid surgeon a viable surgical alternative to prevent postoperative volume depletion, maintain the smooth transition of the lower eyelid to the cheek, and aid in restoring the youthful appearance desired after surgery. This article will focus of periorbital fat grafting and touch upon fat preservation techniques as primary restorative procedures or as surgical adjuncts. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  15. Vein grafting in fingertip replantations.

    Science.gov (United States)

    Yan, Hede; Jackson, William D; Songcharoen, Somjade; Akdemir, Ovunc; Li, Zhijie; Chen, Xinglong; Jiang, Liangfu; Gao, Weiyang

    2009-01-01

    In this retrospective study, the survival rates of fingertip replantation with and without vein grafting were evaluated along with their postoperative functional and cosmetic results. One hundred twenty-one-fingertip amputations were performed in 103 patients between September 2002 and July 2007. Thirty-four amputated fingertips were replanted without vein grafting, while 87 amputated fingertips were replanted with vein grafting for arterial and/or venous repairs. The overall survival rates of the replantations with and without vein grafting were 90% (78/87) and 85% (29/34), respectively. The survival rates were 88% (36/41) with venous repair, 93% (25/27) with arterial repair, and 89% (17/19) with both. Nineteen patients without vein grafting and 48 patients with vein grafting had a follow-up period of more than one year. Good cosmetic and functional outcomes were observed in both groups of patients. The results show that vein grafting is a reliable technique in fingertip replantations, showing no significant difference (P > 0.05) in survival between those with and without vein grafting. Furthermore, no significant difference (P > 0.05) in survival was found between cases with vein grafts for arterial and/or venous repairs. In fingertip replantations with vein grafting, favorable functional and esthetic results can be achieved without sacrificing replantation survival. (c) 2009 Wiley-Liss, Inc.

  16. A Robust Method to Generate Mechanically Anisotropic Vascular Smooth Muscle Cell Sheets for Vascular Tissue Engineering.

    Science.gov (United States)

    Backman, Daniel E; LeSavage, Bauer L; Shah, Shivem B; Wong, Joyce Y

    2017-06-01

    In arterial tissue engineering, mimicking native structure and mechanical properties is essential because compliance mismatch can lead to graft failure and further disease. With bottom-up tissue engineering approaches, designing tissue components with proper microscale mechanical properties is crucial to achieve the necessary macroscale properties in the final implant. This study develops a thermoresponsive cell culture platform for growing aligned vascular smooth muscle cell (VSMC) sheets by photografting N-isopropylacrylamide (NIPAAm) onto micropatterned poly(dimethysiloxane) (PDMS). The grafting process is experimentally and computationally optimized to produce PNIPAAm-PDMS substrates optimal for VSMC attachment. To allow long-term VSMC sheet culture and increase the rate of VSMC sheet formation, PNIPAAm-PDMS surfaces were further modified with 3-aminopropyltriethoxysilane yielding a robust, thermoresponsive cell culture platform for culturing VSMC sheets. VSMC cell sheets cultured on patterned thermoresponsive substrates exhibit cellular and collagen alignment in the direction of the micropattern. Mechanical characterization of patterned, single-layer VSMC sheets reveals increased stiffness in the aligned direction compared to the perpendicular direction whereas nonpatterned cell sheets exhibit no directional dependence. Structural and mechanical anisotropy of aligned, single-layer VSMC sheets makes this platform an attractive microstructural building block for engineering a vascular graft to match the in vivo mechanical properties of native arterial tissue. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Endovascular treatment of acute type B dissection complicating graft-bypass repair for aortic coarctation

    Directory of Open Access Journals (Sweden)

    Serkan Ertugay

    Full Text Available Objectives: The early dissection of the descending aorta after the repair of aortic coarctation is very rare. Herein, we present a special endovascular technique used for acute type B dissection complicating graft bypass for aortic coarctation. Methods: The 48 year-old male patient with the diagnosis of adult type aortic coarctation had bypass procedure between the aortic arch and the descending aorta. Six weeks after the first operation, the patient was readmitted with severe back pain and had the diagnosis of acute type B dissection which involved the descending aorta at the distal part of the graft anastomosis. Results: Two separate stent-grafts were deployed respectively 31 × 150 mm and 34 × 200 mm (C-TAG™ WL Gore&Asc., Flagstaff, AZ, USA. The previous Dacron bypass graft was used as a proximal landing zone for the first stent-graft. The distal landing zone for the second stent was the area between the celiac trunk and superior mesenteric artery. Therefore, the covered stent-graft was implanted to the celiac trunk (Viabahn™ 7 × 50 mm WL Gore&Asc, AZ, USA to maintain its patency before the deployment of the second graft. The segment of coarctation was closed with a vascular plug (Amplatzer™ vascular plug II to prevent persistent perfusion of aneurysmal false lumen. Conclusion: The endovascular approach offers multiple less invasive options based on a patient-specific problem. Keywords: Aortic coarctation, Bypass graft, Endovascular, Vascular plug

  18. Using skeletonised grafts for coronary artery bypass grafting.

    Science.gov (United States)

    Bawany, Faizan Imran; Khan, Muhammad Shahzeb; Khan, Asadullah; Kazi, Abdul Nafey; Naeem, Muhammed

    2014-05-01

    Coronary artery bypass graft surgery relieves angina symptoms and reduces mortality among ischaemic heart disease patients. It remains the gold standard for the treatment of multi-vessel and left main coronary artery disease. It is a well-known fact that internal mammary artery conduits have excellent and long-lasting patency when used for coronary artery bypass grafting. Its supremacy is largely because it prevents atherosclerosis. The old-style internal mammary artery bypass grafting, classically known as pedicle grafting, includes a circular rim of tissue around the graft. Bilateral pedicled internal mammary arteries, especially among diabetic patients, have been reported to cause complications in the sternum like sternal osteomyelitis. In many studies it has been reported that dissection of pedicled internal mammary artery can lead to sternal devascularisation which can lead to higher incidence of infections. Considering the higher incidence of deep sternal infections in patients with double pedicled arterial grafts, dissection of internal mammary artery in skeletonised manner was proposed. In this review, we outline the advantages of skeletonised grafting with respect to incidence of sternal infection, patency rates, blood flow, post-coronary artery bypass graft pain and the length of the graft.

  19. Synthetic smooth muscle in the outer blood plexus of the rhinarium skin of Lemur catta L.

    Science.gov (United States)

    Elofsson, Rolf; Kröger, Ronald H H

    2017-01-01

    The skin of the lemur nose tip (rhinarium) has arterioles in the outer vascular plexus that are endowed with an unusual coat of smooth muscle cells. Comparison with the arterioles of the same area in a number of unrelated mammalians shows that the lemur pattern is unique. The vascular smooth muscle cells belong to the synthetic type. The function of synthetic smooth muscles around the terminal vessels in the lemur rhinarium is unclear but may have additional functions beyond regulation of vessel diameter.

  20. Vascular complications after adult living donor liver transplantation: Evaluation with ultrasonography.

    Science.gov (United States)

    Ma, Lin; Lu, Qiang; Luo, Yan

    2016-01-28

    Living donor liver transplantation (LDLT) has been widely used to treat end-stage liver disease with improvement in surgical technology and the application of new immunosuppressants. Vascular complications after liver transplantation remain a major threat to the survival of recipients. LDLT recipients are more likely to develop vascular complications because of their complex vascular reconstruction and the slender vessels. Early diagnosis and treatment are critical for the survival of graft and recipients. As a non-invasive, cost-effective and non-radioactive method with bedside availability, conventional gray-scale and Doppler ultrasonography play important roles in identifying vascular complications in the early postoperative period and during the follow-up. Recently, with the detailed vascular tracing and perfusion visualization, contrast-enhanced ultrasound (CEUS) has significantly improved the diagnosis of postoperative vascular complications. This review focuses on the role of conventional gray-scale ultrasound, Doppler ultrasound and CEUS for early diagnosis of vascular complications after adult LDLT.

  1. Micrografts: the "super" expansion graft.

    Science.gov (United States)

    Mardovin, W; Miller, S F; Eppinger, M; Finley, R K

    1992-01-01

    A novel technique for producing micronized skin grafts that was introduced in a paper presented at the 1990 ABA meeting was evaluated to quantify maximum expansion. Twenty Sprague-Dawley rats were divided into two groups representing 10:1 and 25:1 expanded micrograft ratios, respectively. Grafted sites in both groups were shown to heal better than those of the control group, and both grafted groups showed comparable healing at day 10.

  2. 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

  3. Late Pseudocoarctation Syndrome After Stent-Graft Implantation For Traumatic Aortic Rupture

    International Nuclear Information System (INIS)

    Letocart, Vincent; Fau, Georges; Tirouvanziam, Ashok; Toquet, Claire; Al Habash, Oussama; Guerin, Patrice; Rousseau, Hervé; Crochet, Dominique

    2013-01-01

    The present observation illustrates an unusual complication occurring after stent-grafting (S-graft) for aortic isthmus rupture. A 22-year-old patient, treated by S-graft in the emergency department for traumatic aortic rupture, was readmitted 10 months later with pseudocoarctation syndrome. A membrane was found inside the stent-graft that had induced a pseudo-dissection, which caused the pseudocoarctation syndrome. Surgical treatment consisted of removing the stent-graft and membrane and replacing it with a vascular implant. The patient’s clinical course was fair. The suggested mechanism was circumferential neoendothelialization of the stent-graft. Dehiscence caused the superior part of the membrane to drop into the lumen of the stent-graft creating a “false channel” that compressed the “true lumen” and induced “pseudocoarctation” syndrome. The cause of the extensive neointimalization remains unexplained. Thoracic aortic stent-grafts require regular follow-up monitoring by angioscan or angio-magnetic resonance imaging.

  4. Fingertip Replantation Using Y-Shaped Vein Graft to Pulp Artery.

    Science.gov (United States)

    Kim, Jun Hyuk; Lee, Young Man

    2015-10-01

    Re-establishing adequate venous outflow is the most important factor for success of fingertip replantation. However, in zone I level, replantation is very difficult, especially in repairing venous circulation. The authors have made an attempt to replantation using Y-shaped vein (YSV) graft to identify and repair veins easily in fingertip replantation. From January 2007 to December 2012, a total of 46 fingertip replantations in 44 consecutive patients with amputations in the Tamai zone I level were performed by using YSV graft. In all patients, arterial anastomosis was performed using YSV graft, and interpositional vein grafts were used for venous repair. The overall success rate of the YSV-grafted replantations was 91.3% (42/46). Postoperative vascular complications occurred in 6 YSV-grafted replantations (13%), and pulp atrophy in the YSV-grafted digits was 9.5% (4/42). Fingertip replantation in zone I level is a difficult territory to a microsurgeon, especially anastomosing veins. However, our YSV grafting technique has shown value in this setting, enabling better esthetic and functional results.

  5. Late Pseudocoarctation Syndrome After Stent-Graft Implantation For Traumatic Aortic Rupture

    Energy Technology Data Exchange (ETDEWEB)

    Letocart, Vincent, E-mail: vincent.letocart@chu-nantes.fr; Fau, Georges, E-mail: georges.fau@chu-nantes.fr; Tirouvanziam, Ashok, E-mail: ashok.tirouvanziam@chu-nantes.fr [University Hospital of Nantes, Institut du Thorax (France); Toquet, Claire, E-mail: claire.toquet@chu-nantes.fr [University Hospital of Nantes, Department of Pathology (France); Al Habash, Oussama, E-mail: oussama.alhabash@chu-nantes.fr; Guerin, Patrice, E-mail: patrice.guerin@chu-nantes.fr [University Hospital of Nantes, Institut du Thorax (France); Rousseau, Herve, E-mail: rousseau.h@chu-toulouse.fr [University Hospital of Toulouse, Department of Radiology (France); Crochet, Dominique, E-mail: dominique.crochet@chu-nantes.fr [University Hospital of Nantes, Institut du Thorax (France)

    2013-06-15

    The present observation illustrates an unusual complication occurring after stent-grafting (S-graft) for aortic isthmus rupture. A 22-year-old patient, treated by S-graft in the emergency department for traumatic aortic rupture, was readmitted 10 months later with pseudocoarctation syndrome. A membrane was found inside the stent-graft that had induced a pseudo-dissection, which caused the pseudocoarctation syndrome. Surgical treatment consisted of removing the stent-graft and membrane and replacing it with a vascular implant. The patient's clinical course was fair. The suggested mechanism was circumferential neoendothelialization of the stent-graft. Dehiscence caused the superior part of the membrane to drop into the lumen of the stent-graft creating a 'false channel' that compressed the 'true lumen' and induced 'pseudocoarctation' syndrome. The cause of the extensive neointimalization remains unexplained. Thoracic aortic stent-grafts require regular follow-up monitoring by angioscan or angio-magnetic resonance imaging.

  6. Midterm Experience of Ipsilateral Axillary-Axillary Arteriovenous Loop Graft as Tertiary Access for Haemodialysis

    Directory of Open Access Journals (Sweden)

    J. P. Hunter

    2014-01-01

    Full Text Available Objectives. To present a series of ipsilateral axillary artery to axillary vein loop arm grafts as an alternative vascular access procedure for haemodialysis in patients with difficult access. Design. Retrospective case series. Methods. Patients who underwent an axillary loop arteriovenous graft from September 2009 to September 2012 were included. Preoperative venous imaging to exclude central venous stenosis and to image arm/axillary veins was performed. A cuffed PTFE graft was anastomosed to the distal axillary artery and axillary vein and looped on the arm. Results. 25 procedures were performed on 22 patients. Median age was 51 years, with 9 males and 13 females. Median number of previous access procedures was 3 (range 0–7. Median followup was 16.4 months (range 1–35. At 3 months and 1 year, the primary and secondary patency rates were 70% and 72% and 36% and 37%, respectively. There were 11 radiological interventions in 6 grafts including 5 angioplasties and 6 thrombectomies. There were 19 surgical procedures in 10 grafts, including thrombectomy, revision, repair for bleeding, and excision. Conclusions. Our series demonstrates that the axillary loop arm graft yields acceptable early patency rates in a complex group of patients but to maintain graft patency required high rates of surgical and radiological intervention, in particular graft thrombectomy.

  7. Environmental application of radiation grafting

    International Nuclear Information System (INIS)

    Tamada, Masao

    2007-01-01

    Adsorbent having high selectivity against a certain metal ion was synthesized by means of radiation-induced graft polymerization for the purpose of environmental application. The resulting adsorbents were utilized for the removal of toxic metal from scallop waste and the collection of uranium from seawater. As a novel application of grafting, the biodegradability of poly-hydroxybutylate was controlled by grafting. The biodegradability could be depressed by the graft chain and then recovered by external stimuli such as thermal and chemical treatments. (author)

  8. Vascular access hemorrhages contribute to deaths among hemodialysis patients.

    Science.gov (United States)

    Ellingson, Katherine D; Palekar, Rakhee S; Lucero, Cynthia A; Kurkjian, Katherine M; Chai, Shua J; Schlossberg, Dana S; Vincenti, Donna M; Fink, Jeffrey C; Davies-Cole, John O; Magri, Julie M; Arduino, Matthew J; Patel, Priti R

    2012-09-01

    In 2007 the Maryland Medical Examiner noted a potential cluster of fatal vascular access hemorrhages among hemodialysis patients, many of whom died outside of a health-care setting. To examine the epidemiology of fatal vascular access hemorrhages, we conducted a retrospective case review in District of Columbia, Maryland, and Virginia from January 2000 to July 2007 and a case-control study. Records from the Medical Examiner and Centers for Medicare and Medicaid Services were reviewed, from which 88 patients were identified as fatal vascular access hemorrhage cases. To assess risk factors, a subset of 20 cases from Maryland was compared to 38 controls randomly selected among hemodialysis patients who died from non-vascular access hemorrhage causes at the same Maryland facilities. Of the 88 confirmed cases, 55% hemorrhaged from arteriovenous grafts, 24% from arteriovenous fistulas, and 21% from central venous catheters. Of 82 case-patients with known location of hemorrhage, 78% occurred at home or in a nursing home. In the case-control analysis, statistically significant risk factors included the presence of an arteriovenous graft, access-related complications within 6 months of death, and hypertension; presence of a central venous catheter was significantly protective. Psychosocial factors and anticoagulant medications were not significant risk factors. Effective strategies to control vascular access hemorrhage in the home and further delineation of warning signs are needed.

  9. Hypoxia and Matrix Manipulation for Vascular Engineering

    Science.gov (United States)

    Abaci, Hasan E.; Hanjaya-Putra, Donny; Gerecht, Sharon

    The great majority of cell types are known to be capable of sensing changes in O2 tension and in the extracellular matrix (ECM), resulting in various responses depending on the cell type and other factors in the microenvironment, such as cell-cell interactions. A growing body of evidence suggests that hypoxia greatly influences the processes of angiogenesis/vasculogenesis through the transcription of several genes, including vascular endothelial growth factor (VEGF), the major regulatory protein of angiogenesis/vasculogenesis. At the same time, the spatial and temporal distribution of ECM components affects ECM properties and growth factor (GF) availability, which, in turn, regulates vascular development. This chapter will discuss how hypoxia and the ECM influence vascular morphogenesis. It seeks a better understanding of vascular development by considering recent research and emerging technologies focused on controlling O2 tension and manipulating ECM properties. The first part of the chapter focuses on the influences of O2 tension and ECM distribution on vascular formation. The second part presents strategies for manipulating the microenvironment using synthetic biomaterials. Control over O2 in three-dimensional (3D) microenvironments is thoroughly highlighted, along with the currently available O2 measurement techniques and mathematical models that are necessary to monitor O2 gradients in 3D microenvironments. Finally, the chapter discusses the state-of-the-art technology in microfluidics and smart biomaterials to provide insight into its future direction.

  10. Angioplasty and Vascular Stenting

    Science.gov (United States)

    ... vessel. Covered stents or stent-grafts have additional advantages over bare stents and are becoming more commonly ... us improve RadiologyInfo.org by taking our brief survey: Survey Do you have a personal story about ...

  11. Supplementing fat grafts with adipose stromal cells for cosmetic facial contouring.

    Science.gov (United States)

    Li, Jie; Gao, Jianhua; Cha, Pengfei; Chang, Qiang; Liao, Yunjun; Liu, Chao; Li, Kecheng; Lu, Feng

    2013-03-01

    Numerous methods have been proposed to enhance the survival of fat grafts, but no definitive treatment is available. Stromal vascular fraction (SVF)-assisted cell therapy offers new perspectives for improving fat graft survival. To determine whether SVF supplementation could improve graft retention in patients undergoing autologous fat grafting for cosmetic improvement of facial contour. We retrospectively analyzed data from 38 women who underwent fat transplantation with SVF (n = 26) or fat grafting alone (n = 12) between October 2010 and January 2012. Each patient underwent computed tomography, and photographs were taken before and 6 months after surgery. The Philips Extended Brilliance Workspace was used for analysis of volume augmentation. All patients showed cosmetic improvements, but the degree varied. No complications were evidenced during follow-up. Fat survival was higher with SVF (64.8 ± 10.2%) than fat grafting alone (46.4 ± 9.3%) (p cosmetic facial contouring can improve the survival of fat grafts over fat grafting alone and provides satisfactory outcomes without major complications. Autologous fat grafting has been used for various cosmetic treatments and difficult reconstructive indications such as temporal depression, wrinkles of nasolabial folds, and hemifacial atrophy, with no incisional scar or complications associated with foreign materials, although problems such as a low rate of graft survival because of early resorption remain. (Aesthet Plast Surg, 14, 1990 and 127) Despite many innovations to overcome these problems, (Dermatol Surg, 26, 2000 and 1159); (Ann Plast Surg, 60, 2008 and 594); (Dermatol Surg, 27, 2001 and 819); (Dermatol Surg, 28, 2002 and 987) we lack a definitive method of fat processing that ensures maximal graft take and viability. (Plast Reconstr Surg, 115, 2005 and 197); (Dermatol Surg, 37, 2011 and 619). © 2012 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

  12. Graft pathology at the time of harvest: impact on long-term survival

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    2014-12-01

    Full Text Available Objective: This study aims to present the graft pathology at the time of harvest and its impact on long-term survival. Methods: The remnants of the bypass grafts from 66 consecutive patients with coronary artery disease receiving a coronary artery bypass grafting were investigated pathologically, and pertinent predictive risk factors and survival were analyzed. Results: Medial degenerative changes with or without intimal proliferation were present in 36.8%, 37.8% and 35.6% of left internal mammary artery (IMA, radial artery and saphenous vein grafts. There were 2 (3.0% hospital deaths and 9 (14.1% late deaths. Multinomial logistic regression revealed left IMA pathological changes, dyslipidemia, history of percutaneous transluminal coronary angioplasty/stent deployment and Y-graft were significant predictive risk factors negatively influencing the patients’ long-term survival. Kaplan-Meier survival analysis revealed that the long-term survival of patients with left IMA pathological changes were significantly reduced compared with those without (74.1% vs. 91.4%, P=0.002; whereas no differences were noted in long-term survivals between patients with and without pathological changes of the radial arterial or saphenous vein grafts. Conclusion: Pathological changes may be seen in the bypass graft at the time of harvest. The subtle ultrastructural modifications and the expressions of vascular tone regulators might be responsible for late graft patency. The pathological changes of the left IMA at the time of harvest rather than those of the radial artery or saphenous vein graft affect significantly longterm survival. Non-traumatic maneuver of left IMA harvest, well-controlled dyslipidemia and avoidance of using composite grafts can be helpful in maintaining the architecture of the grafts.

  13. 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.

  14. Doppler ultrasonography in living donor liver transplantation recipients: Intra- and post-operative vascular complications.

    Science.gov (United States)

    Abdelaziz, Omar; Attia, Hussein

    2016-07-21

    Living-donor liver transplantation has provided a solution to the severe lack of cadaver grafts for the replacement of liver afflicted with end-stage cirrhosis, fulminant disease, or inborn errors of metabolism. Vascular complications remain the most serious complications and a common cause for graft failure after hepatic transplantation. Doppler ultrasound remains the primary radiological imaging modality for the diagnosis of such complications. This article presents a brief review of intra- and post-operative living donor liver transplantation anatomy and a synopsis of the role of ultrasonography and color Doppler in evaluating the graft vascular haemodynamics both during surgery and post-operatively in accurately defining the early vascular complications. Intra-operative ultrasonography of the liver graft provides the surgeon with useful real-time diagnostic and staging information that may result in an alteration in the planned surgical approach and corrections of surgical complications during the procedure of vascular anastomoses. The relevant intra-operative anatomy and the spectrum of normal and abnormal findings are described. Ultrasonography and color Doppler also provides the clinicians and surgeons early post-operative potential developmental complications that may occur during hospital stay. Early detection and thus early problem solving can make the difference between graft survival and failure.

  15. Tough and Sustainable Graft Block Copolymer Thermoplastics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiuyang; Li, Tuoqi; Mannion, Alexander M.; Schneiderman, Deborah K.; Hillmyer, Marc A.; Bates, Frank S. (UMM)

    2016-03-15

    Fully sustainable poly[HPMC-g-(PMVL-b-PLLA)] graft block copolymer thermoplastics were prepared from hydroxypropyl methylcellulose (HPMC), β-methyl-δ-valerolactone (MVL), and l-lactide (LLA) using a facile two-step sequential addition approach. In these materials, rubbery PMVL functions as a bridge between the semirigid HPMC backbone and the hard PLLA end blocks. This specific arrangement facilitates PLLA crystallization, which induces microphase separation and physical cross-linking. By changing the backbone molar mass or side chain composition, these thermoplastic materials can be easily tailored to access either plastic or elastomeric behavior. Moreover, the graft block architecture can be utilized to overcome the processing limitations inherent to linear block polymers. Good control over molar mass and composition enables the deliberate design of HPMC-g-(PMVL-b-PLLA) samples that are incapable of microphase separation in the melt state. These materials are characterized by relatively low zero shear viscosities in the melt state, an indication of easy processability. The simple and scalable synthetic procedure, use of inexpensive and renewable precursors, and exceptional rheological and mechanical properties make HPMC-g-(PMVL-b-PLLA) polymers attractive for a broad range of applications.

  16. In vitro mineralisation of grafted ePTFE membranes carrying carboxylate groups

    Directory of Open Access Journals (Sweden)

    Norsyahidah Mohd Hidzir

    2017-03-01

    Full Text Available In vitro mineralisation in simulated body fluid (SBF of synthetic polymers continues to be an important area of research as the outcomes cannot be predicted. This study evaluates a series of ePTFE membranes grafted with carboxylate-containing copolymers, specifically using acrylic acid and itaconic acid for grafting. The samples differ with regards to graft density, carboxylate density and polymer topology. The type and amount of mineral produced in 1.5 × SBF was dependent on the sample characteristics as evident from XPS, SEM/EDX, and FTIR spectroscopy. It was found that the graft density affects the mineral phases that form and that low graft density appear to cause co-precipitation of calcium carbonate and calcium phosphate. Linear and branched graft copolymer topology led to hydroxyapatite mineralisation whereas crosslinked graft copolymers resulted in formation of a mixture of calcium-phosphate phases. This study demonstrates that in vitro mineralisation outcomes for carboxylate-containing graft copolymers are complex. The findings of this study have implications for the design of bioactive coatings and are important for understanding the bone-biomaterial interface.

  17. Endovascular Placement of an Extraluminal Femoropopliteal Bypass Graft in Human Cadavers

    International Nuclear Information System (INIS)

    Maynar, Manuel; Llorens, Rafael; Lopez-Sanchez, Carmen; Garcia-Martinez, Virginio; Qian Zhong; Lopera, Jorge; Castaneda, Wilfrido R.

    2005-01-01

    Purpose. A method to create an extraluminal femoropopliteal bypass graft using endovascular techniques was evaluated in situ on cadaver extremities in an attempt to develop a minimally invasive alternative technique for the management of infrainguinal occlusive arterial disease. Methods. The endovascular placement of an extraluminal femoropopliteal bypass graft was undertaken in 5 cadaver legs. Following percutaneous access to the popliteal artery (PA) or common femoral artery (CFA), a Rosch-Uchida needle was used to perforate the vascular wall, followed by the creation of an extraluminal tract using a looped wire and catheter. Once the desired level was reached the needle was again used to perforate the vascular wall of the proximal superficial femoral artery (SFA) or PA depending on the access used. Self-expanding expanded polytetrafluoroethylene (ePTFE) stent-grafts were then deployed to establish the extraluminal femoropopliteal bypass connecting the two arterial puncture sites. Following dilatation of the stent-graft, angiography was performed to assess the endoprostheses and to look for contrast leaks. Results. Technical success was achieved in all 5 legs. Procedure time varied from 15 to 30 min. The angiographic studies performed immediately after completion of the bypass procedure showed patency of the grafts with no evidence of kinking or leakage in any of the cases. Conclusion. This study has proved that the endovascular placement of an extraluminal femoropopliteal bypass graft in human cadaver legs using endovascular techniques under fluoroscopic control is technically feasible

  18. [Scaphoid pseudarthrosis : Indications for avascular iliac crest or radius bone grafts].

    Science.gov (United States)

    Asmus, A; Lautenbach, M; Schacher, B; Kim, S; Eisenschenk, A

    2016-11-01

    Operative treatment of the scaphoid nonunion includes avascular corticocancellous and cancellous bone grafts and increasingly the use of vascular pedicled and free vascular corticocancellous grafts. Especially the latter require a fair amount of operative expertise and experience in microsurgical techniques. Which criteria lead to the decision for or against an avascular graft used for reconstruction of scaphoid nonunion? Is our current classification system of a scaphoid pseudarthrosis able to illustrate our diagnostic potential in a way that makes us refer to operative procedures? Evaluation of current literature and expert opinions RESULTS: Avascular bone grafts show a high union rate as long as a sufficient vascularisation of the remaining fragments is present. In general, patients benefit from a very good functional outcome. Even revisions of failed scaphoid union may be successfully treated with an avascular bone graft. Failures of union are repeatedly experienced in treating proximal pole fractures with critical vascularisation or extensive bone loss, especially including avascular necrosis of the proximal pole (AVN). Current classification systems do not allow description and correlation of morphologic findings so as to compare results profoundly and to recommend specific procedures. As long as sufficient vascularisation of remaining fragments is seen, the avascular bone graft is eligible for reconstructing scaphoid nonunion. Classification systems do not seem to reflect the status quo of diagnostic possibilities and make it difficult to provide guidelines for state-of-the-art operative procedures.

  19. Suction blister grafting - Modifications for easy harvesting and grafting

    Directory of Open Access Journals (Sweden)

    2012-01-01

    Full Text Available Suction blister grafting is a simple modality of treatment of patients with resistant and stable vitiligo. But raising the blisters may be time consuming and transferring to the recipient site may be difficult as the graft is ultrathin. By doing some modifications we can make the technique simpler and easier. We can decrease the blister induction time by intradermal injection of saline, exposure to Wood′s lamp, intrablister injection of saline. By these methods we can decrease the blister induction time from 2-3 hrs to 45-90 minutes. After harvesting the graft, it can be transferred to the recipient area by taking the graft on a sterile glass slide, on the gloved finger, rolling the graft over a sterile syringe and then spreading on the recipient area, or taking on the sterile wrapper of paraffin dressing and then placing over the recipient area.

  20. Vascularity in thyroid neoplasms

    DEFF Research Database (Denmark)

    Larsen, Karen Kjaer; Andersen, Niels Frost; Melsen, Flemming

    2006-01-01

    The aim of the present study was to evaluate the reliability of four different methods (vascular grading, Chalkley count, microvessel density (MVD) and stereological estimation) for quantifying intratumoral microvascularity in thyroid neoplasms, by comparing the variability within and between...... count should be the preferred method for assessing microvascularity in thyroid neoplasms. The diagnostic evaluation revealed a tendency towards higher degree of vascularity in FA compared to both FC and PC for all methods. No statistically significant association was seen between vascular density...

  1. [From synthetic biology to synthetic humankind].

    Science.gov (United States)

    Nouvel, Pascal

    2015-01-01

    In this paper, we propose an historical survey of the expression "synthetic biology" in order to identify its main philosophical components. The result of the analysis is then used to investigate the meaning of the notion of "synthetic man". It is shown that both notions share a common philosophical background that can be summed up by the short but meaningful assertion: "biology is technology". The analysis allows us to distinguish two notions that are often confused in transhumanist literature: the notion of synthetic man and the notion of renewed man. The consequences of this crucial distinction are discussed. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  2. Synthetic Cathinones ("Bath Salts")

    Science.gov (United States)

    ... cathinones? Behavioral therapy can be used to treat addiction to synthetic cathinones. Examples include: cognitive-behavioral therapy contingency management, or motivational incentives—providing rewards to ...

  3. Bone Grafts in Jaw Cysts- Hydroxyapatite & Allogenic Bone – A Comparative Study

    Directory of Open Access Journals (Sweden)

    Showkat Mamun

    2009-11-01

    Full Text Available Background: Auto bone is the gold standard in bone grafting. However, the morbidity and additional surgical time associated with its collection, as well as the limited supply, have stimulated the search for substitutes. Allograft is more limited than autograft because it yields more variable clinical results. Composite synthetic grafts offer an alternative because Hydroxyapatite is chemically identical to the inorganic matrix of living bones and it can be processed synthetically. The intent was to evaluate these two graft materials for clinical use and to provide an insight on the different grafting strategies to enhance bone formation. Objective: To find out the bone healing process and the prognostic value for the patient using hydroxyapatite alloplastic material and allogenic bone graft. Method: Total 28 patients were included in the study after the clinical and radiological evaluation where 14 cases were treated with allogenic-bone graft and rest 14 cases were treated with hydroxyapatite alloplastic material after enucleation of the cystic lesion in random manner. The integration of hydroxyapatite and allogenic bone was assessed with postoperative lesion diameter, trabecular pattern, histopathological and scintigraphic examination of the successful graft cases. Statistical analysis was carried out by ‘unpaired T test' and ‘Chi square' test. Result: The radiological, histopathological and scintigraphical outcome of the patients treated with hydroxyaptite granule bone graft were clinically and statistically superior in comparison with those who were treated with allogenic bone graft. Conclusion: This safe and osteoconductive hydroxyapatite appears suitable for filling bone defects and bone cavities, showing less resorption and a rapid osseous integration. Key words: Hydroxyapatite; allogenic bone; scintigraphy; radiology; histopathology.DOI: 10.3329/bsmmuj.v2i1.3707 BSMMU J 2009; 2(1: 25-30

  4. Osteoinductive potential of a novel biphasic calcium phosphate bone graft in comparison with autographs, xenografts, and DFDBA.

    Science.gov (United States)

    Miron, Richard J; Sculean, Anton; Shuang, Yang; Bosshardt, Dieter D; Gruber, Reinhard; Buser, Daniel; Chandad, Fatiha; Zhang, Yufeng

    2016-06-01

    Since the original description of osteoinduction in the early 20th century, the study and development of innovative biomaterials has emerged. Recently, novel synthetic bone grafts have been reported with potential to form ectopic bone in vivo. However, their full characterization in comparison with other leading bone grafts has not been investigated. The aim of this study was to determine the osteoinductive potential of bone grafts by comparing autogenous bone grafts, demineralized freeze-dried bone allografts (DFDBA), a commonly utilized natural bone mineral (NBM) from bovine origin (Bio-Oss), and a newly developed biphasic calcium phosphate (BCP). Grafts were compared in vitro for their ability to stimulate bone marrow stromal cell (BMSC) migration, proliferation, and differentiation as assessed by quantitative real-time PCR for genes coding for bone markers including Runx2, collagen I, and osteocalcin. Furthermore, bone grafts were implanted in the calf muscle of 12 beagle dogs to determine their potential to form ectopic bone in vivo. The in vitro results demonstrate that both autografts and DFDBA show potential for cell recruitment, whereas only autografts and BCP demonstrated the ability to differentiate BMSCs toward the osteoblast lineage. The in vivo ectopic bone model demonstrated that while NBM particles were not osteoinductive and autogenous bone grafts were resorbed quickly in vivo, ectopic bone formation was reported in DFDBA and in synthetic BCP grafts. The modifications in nanotopography and chemical composition of the newly developed BCP bone grafts significantly promoted ectopic bone formation confirming their osteoinductive potential. In conclusion, the results from this study provide evidence that synthetic bone grafts not only serve as a three-dimensional scaffold but are also able to promote osteoinduction. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Preoperative and postoperative evaluation of vascular diseases by 111In-oxine platelet scintigraphy

    International Nuclear Information System (INIS)

    Nishibe, Toshiya; Hiraoka, Tomoya; Sakuma, Makoto; Sakai, Keisuke; Yasuda, Keishu; Tanabe, Tatsuzo; Nagao, Kazuhiko; Ito, Kazuo

    1991-01-01

    111 In-oxine platelet scintigraphy was performed on 20 patients with various vascular diseases to assess its clinical usefulness as a diagnostic procedure. Especially we evaluated its usefulness for thrombus formation after Ivaron sponge occlusion method (ISO method) and endotheliazation of prosthetic grafts. Negative image in thoracic false lumen was obtained 2 or 3 weeks after operation in all patients whose dissection was completely repaired by ISO method. It suggested early thromboexclusion in thoracic false lumen in which Ivalon sponge was implanted. Negative image was observed in two cases of saphenous vein graft and one of Dacron graft. The case of Dacron graft was examined 415 days after implantation. Negative result in this case would be accounted for by stabilized fibrin layer or good endothelial coverrage. The results suggest that 111 In-oxine platelet scintigraphy is an appropriate technique for evaluating the encapsulation of prosthetic grafts and thromboexclusion after ISO method. (author)

  6. Paediatric fingertip composite grafts: Do they all go black?

    Science.gov (United States)

    Murphy, Adrian D; Keating, Cameron P; Penington, Anthony; McCombe, David; Coombs, Chris J

    2017-02-01

    Fingertip injuries are amongst the most frequently seen hand injuries in the paediatric population. The present study evaluated the composite graft survival rate in distal digital amputations with respect to injury type, amputation level and time to surgery. We performed a retrospective review of patients who underwent composite grafting of fingertip injuries over an 11-year period at a paediatric hospital. All children who underwent non-vascularized replantation of amputated fingertips were included. Patients were excluded if they failed to attend at least one follow-up appointment. Demographic information was recorded. The nature and level of injury and time to surgery was also recorded. Graft viability was characterized as no take, partial take, or complete take. The number of secondary procedures and number and duration of follow-up appointments were recorded. A total of 105 patients underwent fingertip composite grafting, of whom 96 were suitable for inclusion in this study. The median age was 2.4 years (0-16 years); there were 48 boys (46%) and 57 girls (54%). Thirty-one patients had no graft take (32%), 50 patients had partial take (52%) and 15 patients had complete take (16%). Only two patients underwent secondary revision (2%). The median number of follow-up appointments was 4, and the mean follow-up time was 68 days. Time to surgery or level of amputation did not have a statistically significant influence on outcome. Over two-thirds of composite grafts in children showed some degree of take, albeit partially in the majority. Morbidity was low, and most children did not require further surgery. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  7. Bone grafting options in children.

    Science.gov (United States)

    Betz, Randal R; Lavelle, William F; Samdani, Amer F

    2010-08-01

    Retrospective review of the literature. To review the current literature as well as recent trends in bone grafting techniques available for children. The currently accepted gold standard in bone grafting for adolescent idiopathic scoliosis (AIS) is autogenous iliac crest. Due to questions concerning complications such as donor site pain, other options have been explored, including various allograft sources, demineralized bone matrix, and bone morphogenetic protein. A review of the current medical literature was completed and additional case examples are presented. A review of the literature reveals that up to 31% of patients have persistent pain at 2 years post surgery when autogenous iliac crest bone graft is harvested. Allograft supplementation of local autograft has been demonstrated in the literature to be as effective as autogenous iliac crest bone grafting in contributing to a successful posterior spinal fusion in patients with AIS. Modern demineralized bone matrix formulations have been found in both animal models as well as in a recent retrospective clinical review to contribute to a successful posterior spinal fusion in AIS. Bone morphogenetic protein has been shown to contribute to a successful posterior spinal fusion in complex pediatric spinal deformity patients. At 2 years follow-up, patients who underwent a posterior instrumented spinal fusion that was not augmented with any bone graft appear to have successful spinal fusions. Although autogenous iliac bone graft remains the benchmark to which bone grafting materials are compared, other options including the placement of no bone graft at all provides similar fusion rates in patients with AIS.

  8. Vascularized fibular transfer in longstanding and infected large bone defects.

    Science.gov (United States)

    Lê Thua, Trung-Hau; Pham, Dang-Nhat; Boeckx, Willy; De Mey, Albert

    2014-03-01

    The reconstruction of large bone defects in the infectious environment is still a big challenge for limb salvage because of disturbance in bacterial flora, bacterial resistance and limitation of blood supply at scarred tissue. This retrospective study was to evaluate long-term outcomes in patients who were performed vascularized fibular transfers for treatment of large bone defects in the infectious environment. The review included 26 patients with an average age of 27 years old. Bone defects were located at the arm in 1 patient, the forearm in 2 patients, the thigh in 6 patients and the leg in 17 patients. The cause of the bone defects included high-energy trauma in 14 cases, chronic osteomyelitis in 7 cases, infected non-union in 5 cases. All patients had had several previous operative procedures. The average length of fibular vascularized graft was 16.6 cm (range, 10-22 cm), and the average size of the associated fasciocutaneous component in 16 patients was 3.6 x 8.5 cm. Three patients had partial necrosis of skin paddle. Three patients, who were stabilized by screw and external fixator, had an infection at the distal part of the fibular graft and pin tracts. 25 fibular grafts (96%) showed complete bone union. This review has showed that the vascularized fibular transfer can be effective for management of large segmental bone defects in the infectious environment.

  9. Autologous fat grafting: use of closed syringe microcannula system for enhanced autologous structural grafting

    Directory of Open Access Journals (Sweden)

    Alexander RW

    2013-04-01

    Full Text Available Robert W Alexander,1 David Harrell2 1Department of Surgery, School of Medicine and Dentistry, University of Washington, Seattle, WA, USA; 2Harvest-Terumo Inc, Plymouth, MA, USA Objectives: Provide background for use of acquiring autologous adipose tissue as a tissue graft and source of adult progenitor cells for use in cosmetic plastic surgery. Discuss the background and mechanisms of action of closed syringe vacuum lipoaspiration, with emphasis on accessing adipose-derived mesenchymal/stromal cells and the stromal vascular fraction (SVF for use in aesthetic, structural reconstruction and regenerative applications. Explain a proven protocol for acquiring high-quality autologous fat grafts (AFG with use of disposable, microcannula systems. Design: Explain the components and advantage of use of the patented super luer-lock and microcannulas system for use with the closed-syringe system. A sequential explanation of equipment selection for minimally traumatic lipoaspiration in small volumes is presented, including use of blunt injection cannulas to reduce risk of embolism. Results: Thousands of AFG have proven safe and efficacious for lipoaspiration techniques for large and small structural fat grafting procedures. The importance and advantages of gentle harvesting of the adipose tissue complex has become very clear in the past 5 years. The closed-syringe system offers a minimally invasive, gentle system with which to mobilize subdermal fat tissues in a suspension form. Resulting total nuclear counting of undifferentiated cells of the adipose-derived -SVF suggests that the yield achieved is better than use of always-on, constant mechanical pump applied vacuum systems. Conclusion: Use of a closed-syringe lipoaspiration system featuring disposable microcannulas offers a safe and effective means of harvesting small volumes of nonmanipulated adipose tissues and its accompanying progenitor cells within the SVF. Closed syringes and microcannulas are

  10. Vascular access for hemodialysis: current perspectives

    Directory of Open Access Journals (Sweden)

    Santoro D

    2014-07-01

    Full Text Available Domenico Santoro,1 Filippo Benedetto,2 Placido Mondello,3 Narayana Pipitò,2 David Barillà,2 Francesco Spinelli,2 Carlo Alberto Ricciardi,1 Valeria Cernaro,1 Michele Buemi11Department of Clinical and Experimental Medicine, Unit of Nephrology, 2Unit of Vascular Surgery, 3Unit of Infectious Disease, University of Messina, ItalyAbstract: A well-functioning vascular access (VA is a mainstay to perform an efficient hemodialysis (HD procedure. There are three main types of access: native arteriovenous fistula (AVF, arteriovenous graft, and central venous catheter (CVC. AVF, described by Brescia and Cimino, remains the first choice for chronic HD. It is the best access for longevity and has the lowest association with morbidity and mortality, and for this reason AVF use is strongly recommended by guidelines from different countries. Once autogenous options have been exhausted, prosthetic fistulae become the second option of maintenance HD access alternatives. CVCs have become an important adjunct in maintaining patients on HD. The preferable locations for insertion are the internal jugular and femoral veins. The subclavian vein is considered the third choice because of the high risk of thrombosis. Complications associated with CVC insertion range from 5% to 19%. Since an increasing number of patients have implanted pacemakers and defibrillators, usually inserted via the subclavian vein and superior vena cava into the right heart, a careful assessment of risk and benefits should be taken. Infection is responsible for the removal of about 30%–60% of HD CVCs, and hospitalization rates are higher among patients with CVCs than among AVF ones. Proper VA maintenance requires integration of different professionals to create a VA team. This team should include a nephrologist, radiologist, vascular surgeon, infectious disease consultant, and members of the dialysis staff. They should provide their experience in order to give the best options to uremic

  11. Radiation grafting on natural films

    Science.gov (United States)

    Lacroix, M.; Khan, R.; Senna, M.; Sharmin, N.; Salmieri, S.; Safrany, A.

    2014-01-01

    Different methods of polymer grafting using gamma irradiation are reported in the present study for the preparation of newly functionalized biodegradable films, and some important properties related to their mechanical and barrier properties are described. Biodegradable films composed of zein and poly(vinyl alcohol) (PVA) were gamma-irradiated in presence of different ratios of acrylic acid (AAc) monomer for compatibilization purpose. Resulting grafted films (zein/PVA-g-AAc) had their puncture strength (PS=37-40 N mm-1) and puncture deformation (PD=6.5-9.8 mm) improved for 30% and 50% PVA in blend, with 5% AAc under 20 kGy. Methylcellulose (MC)-based films were irradiated in the presence of 2-hydroxyethyl methacrylate (HEMA) or silane, in order to determine the effect of monomer grafting on the mechanical properties of films. It was found that grafted films (MC-g-HEMA and MC-g-silane) using 35% monomer performed higher mechanical properties with PS values of 282-296 N mm-1 and PD of 5.0-5.5 mm under 10 kGy. Compatibilized polycaprolactone (PCL)/chitosan composites were developed via grafting silane in chitosan films. Resulting trilayer grafted composite film (PCL/chitosan-g-silane/PCL) presented superior tensile strength (TS=22 MPa) via possible improvement of interfacial adhesion (PCL/chitosan) when using 25% silane under 10 kGy. Finally, MC-based films containing crystalline nanocellulose (CNC) as a filling agent were prepared and irradiated in presence of trimethylolpropane trimethacrylate (TMPTMA) as a grafted plasticizer. Grafted films (MC-g-TMPTMA) presented superior mechanical properties with a TS of 47.9 MPa and a tensile modulus (TM) of 1792 MPa, possibly due to high yield formation of radicals to promote TMPTMA grafting during irradiation. The addition of CNC led to an additional improvement of the barrier properties, with a significant 25% reduction of water vapor permeability (WVP) of grafted films.

  12. Quantum synthetic aperture radar

    Science.gov (United States)

    Lanzagorta, Marco; Jitrik, Oliverio; Uhlmann, Jeffrey; Venegas-Andraca, Salvador E.

    2017-05-01

    Synthetic aperture radar (SAR) uses sensor motion to generate finer spatial resolution of a given target area. In this paper we explore the theoretical potential of quantum synthetic aperture quantum radar (QSAR). We provide theoretical analysis and simulation results which suggest that QSAR can provide improved detection performance over classical SAR in the high-noise low-brightness regime.

  13. Designing synthetic biology.

    Science.gov (United States)

    Agapakis, Christina M

    2014-03-21

    Synthetic biology is frequently defined as the application of engineering design principles to biology. Such principles are intended to streamline the practice of biological engineering, to shorten the time required to design, build, and test synthetic gene networks. This streamlining of iterative design cycles can facilitate the future construction of biological systems for a range of applications in the production of fuels, foods, materials, and medicines. The promise of these potential applications as well as the emphasis on design has prompted critical reflection on synthetic biology from design theorists and practicing designers from many fields, who can bring valuable perspectives to the discipline. While interdisciplinary connections between biologists and engineers have built synthetic biology via the science and the technology of biology, interdisciplinary collaboration with artists, designers, and social theorists can provide insight on the connections between technology and society. Such collaborations can open up new avenues and new principles for research and design, as well as shed new light on the challenging context-dependence-both biological and social-that face living technologies at many scales. This review is inspired by the session titled "Design and Synthetic Biology: Connecting People and Technology" at Synthetic Biology 6.0 and covers a range of literature on design practice in synthetic biology and beyond. Critical engagement with how design is used to shape the discipline opens up new possibilities for how we might design the future of synthetic biology.

  14. Development of Graft-Site Candidiasis in 3 Solid Organ Transplant Recipients from the Same Donor.

    Science.gov (United States)

    El-Bandar, Nasrin; Kroy, Daniela C; Fuller, Tom Florian; Kramer, Jürgen; Liefeldt, Lutz; Budde, Klemens; Blobel, Conrad; Miller, Kurt; Friedersdorff, Frank

    2017-07-11

    BACKGROUND Graft-site candidiasis rarely develops in solid organ transplant recipients; however, severe life-threatening complications can occur. We report the course of 3 solid organ transplant recipients developing graft-site candidiasis. CASE REPORT All grafts, consisting of 2 kidneys and 1 liver, were procured from a single donor. Patient data were collected from our database. Candida albicans was isolated from a swab taken during multiple-organ recovery. Complications associated with candidiasis occurred in all 3 recipients with preservation of the liver transplant. Both renal transplant recipients had vascular complications, eventually resulting in graft nephrectomy and subsequent return to dialysis. The patients recovered completely without residual effects of their prior fungal infection. CONCLUSIONS Fungal infections in solid organ transplant recipients are rare. Since the sequelae of these infections are serious and usually pertain to more than 1 recipient at a time, antifungal prophylaxis may be warranted in select donors.

  15. In-111 oxine autologous labeled platelets in the diagnosis of kidney graft rejection

    International Nuclear Information System (INIS)

    Martin-Comin, J.; Roca, M.; Grino, J.M.; Paradell, C.; Caralps, C.

    1983-01-01

    The usefulness of In-111 oxine labeled autologous platelets in the diagnosis of renal graft rejection was studied. The method is based on imaging of the graft area at 4, 24, 48, and 72 hours after the injection of the labeled cells. The study was done in 31 renal transplant recipients. The control group included four patients with normal renal function without evidence of rejection. No platelet uptake was observed in any of them. The study group included 22 patients with acute rejection which was confirmed histologically in 13. One case of chronic vascular type rejection of the graft tracer uptake was seen. There was a false-positive result due to a perirenal hematoma. In three patients with a non-immunological sudden impairment of renal function, no activity was detected in the graft area. We also evaluated the changes in platelet trapping throughout the study and they seemed to correlate with the response to the antirejection therapy

  16. Synthetic bone substitute engineered with amniotic epithelial cells enhances bone regeneration after maxillary sinus augmentation.

    Directory of Open Access Journals (Sweden)

    Barbara Barboni

    Full Text Available BACKGROUND: Evidence has been provided that a cell-based therapy combined with the use of bioactive materials may significantly improve bone regeneration prior to dental implant, although the identification of an ideal source of progenitor/stem cells remains to be determined. AIM: In the present research, the bone regenerative property of an emerging source of progenitor cells, the amniotic epithelial cells (AEC, loaded on a calcium-phosphate synthetic bone substitute, made by direct rapid prototyping (rPT technique, was evaluated in an animal study. MATERIAL AND METHODS: Two blocks of synthetic bone substitute (∼0.14 cm(3, alone or engineered with 1×10(6 ovine AEC (oAEC, were grafted bilaterally into maxillary sinuses of six adult sheep, an animal model chosen for its high translational value in dentistry. The sheep were then randomly divided into two groups and sacrificed at 45 and 90 days post implantation (p.i.. Tissue regeneration was evaluated in the sinus explants by micro-computer tomography (micro-CT, morphological, morphometric and biochemical analyses. RESULTS AND CONCLUSIONS: The obtained data suggest that scaffold integration and bone deposition are positively influenced by allotransplantated oAEC. Sinus explants derived from sheep grafted with oAEC engineered scaffolds displayed a reduced fibrotic reaction, a limited inflammatory response and an accelerated process of angiogenesis. In addition, the presence of oAEC significantly stimulated osteogenesis either by enhancing bone deposition or making more extent the foci of bone nucleation. Besides the modulatory role played by oAEC in the crucial events successfully guiding tissue regeneration (angiogenesis, vascular endothelial growth factor expression and inflammation, data provided herein show that oAEC were also able to directly participate in the process of bone deposition, as suggested by the presence of oAEC entrapped within the newly deposited osteoid matrix and by their

  17. The Safety and Efficacy of Cell-Assisted Fat Grafting to Traditional Fat Grafting in the Anterior Mid-Face: An Indirect Assessment by 3D Imaging.

    Science.gov (United States)

    Sasaki, Gordon H

    2015-12-01

    Numerous methodologies and algorithms have been suggested to enhance fat graft survival, including the usage of stromal vascular fraction (SVF) and platelet-rich plasma (PRP), but no long-term studies are available. This single-center prospective, case-controlled study investigated the safety and efficacy of combining a modified Baker-designed lateral SMASectomy or plication face lift with simultaneous anterior mid-face grafting into site-specific compartments by (1) conventional Coleman's technique or (2) Yoshimura's cell-assisted lipografting technique. On the voluntary principle, candidates selected one of four techniques for volumization of their mid-face: conventional fat grafting; PRP-assisted fat grafting; SVF-assisted fat grafting; and PRP/SVF- assisted fat grafting. For comparison data, comparable fat volumes, SVF volumes and nucleated cells, and PRP volumes and platelet concentrations were injected into each designated group. Indirect volume retentions were determined by standardized Vectra 3D analyses up to 1 year. PRP, SVF, and PRP/SVF cell supplementation of processed fat resulted in statistically significant percent mean graft retention over their baseline control at 12 months (p facial aesthetic surgery. With refinements in the entire grafting process and the potential benefits of autologous cell approaches with SVF and PRP, future evidence-based controlled studies under regulatory approval may improve graft survival in a safe and effective manner. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

  18. Vascular disease: Hemorrhage

    International Nuclear Information System (INIS)

    Norman, D.

    1987-01-01

    An understanding of the role of magnetic resonance (MR) in detection and characterization of vascular lesions is evolving. Improvements in spatial detail suggest great promise in delineation of structural vascular lesions, and insights into the appearance of evolving intraparenchymal hematoma have broadened the applications

  19. Vascular grading of angiogenesis

    DEFF Research Database (Denmark)

    Hansen, S; Grabau, D A; Sørensen, Flemming Brandt

    2000-01-01

    The study aimed to evaluate the prognostic value of angiogenesis by vascular grading of primary breast tumours, and to evaluate the prognostic impact of adding the vascular grade to the Nottingham Prognostic Index (NPI). The investigation included 836 patients. The median follow-up time was 11...... was moderately reproduced (kappa = 0.59). Vascular grade was significantly associated with axillary node involvement, tumour size, malignancy grade, oestrogen receptor status and histological type. In univariate analyses vascular grade significantly predicted recurrence free survival and overall survival for all...... impact for 24% of the patients, who had a shift in prognostic group, as compared to NPI, and implied a better prognostic dissemination. We concluded that the angiogenesis determined by vascular grading has independent prognostic value of clinical relevance for patients with breast cancer....

  20. 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.

  1. David M. Hume Memorial Lecture. Impact of endovascular technology on the practice of vascular surgery.

    Science.gov (United States)

    Veith, F J; Marin, M L

    1996-08-01

    Endovascular treatment techniques have already replaced some vascular operations. The likelihood is that new endovascular techniques involving stents and stented grafts will replace additional vascular operations. All these treatments involve the use of catheter-guidewire, balloon, and imaging modalities, particularly digital fluoroscopy. These modalities have already and will increasingly help to improve and simplify standard vascular operations such as thromboembolectomy, infrainguinal bypasses, and management of aneurysms and arteriovenous fistulas. Accordingly, vascular surgeons must become familiar with and use these endovascular methods and techniques. This can be accomplished in a variety of ways which includes working as part of a multidisciplinary vascular treatment group in which various specialists collaborate to provide the best, most cost-effective care to vascular disease patients.

  2. Graft intolerance syndrome requiring graft nephrectomy after late kidney graft failure: can it be predicted? A retrospective cohort study.

    Science.gov (United States)

    Bunthof, Kim L W; Verhoeks, Carmen M; van den Brand, Jan A J G; Hilbrands, Luuk B

    2018-02-01

    Graft nephrectomy is recommended in case of early graft failure. When the graft fails more than 3-6 months after transplantation, it is current practice to follow a wait-and-see policy. A common indication for graft removal is the graft intolerance syndrome. We aimed to create a risk prediction model for the occurrence of graft intolerance resulting in graft nephrectomy. We collected data of kidney transplantations performed in our center between 1980 and 2010 that failed at least 6 months after transplantation. We evaluated the association between baseline characteristics and the occurrence of graft nephrectomy because of graft intolerance using a competing risk regression model. Prognostic factors were included in a multivariate prediction model. In- and exclusion criteria were met in 288 cases. In 48 patients, the graft was removed because of graft intolerance. Donor age, the number of rejections, and shorter graft survival were predictive factors for graft nephrectomy because of the graft intolerance syndrome. These factors were included in a prediction rule. Using donor age, graft survival, and the number of rejections, clinicians can predict the need for graft nephrectomy with a reasonable accuracy. © 2017 Steunstichting ESOT.

  3. Comparison of FLIXENE™ and standard PTFE arteriovenous graft for early haemodialysis.

    Science.gov (United States)

    Chiang, Nathaniel; Hulme, Katherine Ria; Haggart, Paul Charles; Vasudevan, Thodur

    2014-01-01

    The purpose is to compare the outcomes of FLIXENE™ arteriovenous graft (AVG) to standard polytetrafluoroethylene (PTFE) AVG for early haemodialysis. This is a prospective observational study of all AVGs placed over a 40-month period between 2008 and 2011 at our vascular unit. Primary outcome was to examine early cannulation rates for FLIXENE™. Secondary outcomes included patency rates, usability of grafts, complications in particular infections, interventions and death in comparison to standard PTFE grafts. Forty-five FLIXENE™ and 19 standard PTFE AVGs were placed in the study period; 89% of FLIXENE™ grafts were used for dialysis, with 78% cannulated within 3 days. At 18 months, primary patency (FLIXENE™ 34% vs standard PTFE 24%), primary assisted patency (35% vs 36%) and secondary patency rate (51% vs 48%) were not statistically different; 20.2% of FLIXENE™ grafts were infected at 18 months requiring explantation compared with 40.3% of standard PTFE grafts (p=0.14). FLIXENE™ can be cannulated for dialysis within 3 days. It has similar patency and complication rates as other prosthetic grafts in the market. In patients who have no access and require urgent dialysis, FLIXENE™ is a viable option.

  4. Revascularisation pattern of ruptured flexor tendon grafts in anterior cruciate ligament reconstruction: A histological study.

    Science.gov (United States)

    Figueroa, D; Martínez, R; Calvo, R; Scheu, M; Gallegos, M; Vaisman, A; Martínez, C; González, A

    For successful anterior cruciate ligament (ACL) reconstruction, revascularisation and histological maturation are necessary, as their failure can cause graft rupture. The purpose of this study was to describe differences in the histological maturation of early failed plasty (less than 12 months after surgery) and late failed plasty (more than 12 months after surgery) in patients with re-rupture after ACL reconstruction with hamstring tendons. A descriptive observational study was conducted on a consecutive series of 20 patients whose ACL reconstruction had failed. Graft biopsy samples were obtained during the revision surgery from the proximal, medial, and distal graft remnants. The samples were evaluated by light microscopy, and the vascularity and maturation of the samples were established by histological scoring. The most common aetiology of reconstruction failure (86.6%) was a specific event with non-contact mechanism. The patients with re-rupture of their ACL plasty less than 12 months after surgery had substance vessels that were less deep. The distal segment of the graft in those patients showed a delay in histological maturation with fewer collagen fibres. In patients whose ACL grafts failed less than 12 months after surgery, a lower distribution of blood vessels and collagen fibres was found that were less ordered in the distal graft. These results indicate a delay in maturation, which leads to a higher risk of graft failure. Copyright © 2016 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

  5. Early Vascular Thrombosis After Kidney Transplantation: Can We Predict Patients at Risk?

    Science.gov (United States)

    de Freitas, R A P; de Lima, M L; Mazzali, M

    2017-05-01

    Renal transplant is the therapy of choice for patients with chronic renal disease. In recent years, improvement in immunosuppressive drugs reduced early graft loss associated with acute rejection. However, vascular thrombosis, accounting for 5% of early graft loss, can sensitize the recipient for human leukocyte antibodies, reducing the chance for a second transplant. The aim of this study was to identify risk factors for vascular thrombosis in a single transplant center, to design specific prevention protocol. This was a retrospective, case-control study. From the Renal Transplant Unit database, we identified 21 cases of vascular thrombosis in recipients of kidneys from deceased donors. Recipients from the contralateral kidney from the same donor, without vascular complications, were assigned to the control group. Data analyzed included donor, recipient, transplant surgery, and post-operative follow-up. The local ethics committee approved the protocol. Thrombosis and control groups were comparable for recipient characteristics, cold ischemia time, organ side (right or left), and site of arterial anastomosis. We observed an increased risk for vascular thrombosis in kidneys with multiple veins (odds ratio, 11.32; P = .03). Organ retrieval surgery complications, such as vascular lesions or heterogeneous perfusion, despite normal pre-implantation biopsy, were considered risk factors for vascular thrombosis within the first post-operative day (odds ratio, 7.1; P = .03). In this series, multiple renal vein and organ retrieval surgery complications were risk factors for early vascular thrombosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Synthetic virology: engineering viruses for gene delivery.

    Science.gov (United States)

    Guenther, Caitlin M; Kuypers, Brianna E; Lam, Michael T; Robinson, Tawana M; Zhao, Julia; Suh, Junghae

    2014-01-01

    The success of gene therapy relies heavily on the performance of vectors that can effectively deliver transgenes to desired cell populations. As viruses have evolved to deliver genetic material into cells, a prolific area of research has emerged over the last several decades to leverage the innate properties of viruses as well as to engineer new features into them. Specifically, the field of synthetic virology aims to capitalize on knowledge accrued from fundamental virology research in order to design functionally enhanced gene delivery vectors. The enhanced viral vectors, or 'bionic' viruses, feature engineered components, or 'parts', that are natural (intrinsic to viruses or from other organisms) and synthetic (such as man-made polymers or inorganic nanoparticles). Various design strategies--rational, combinatorial, and pseudo-rational--have been pursued to create the hybrid viruses. The gene delivery vectors of the future will likely criss-cross the boundaries between natural and synthetic domains to harness the unique strengths afforded by the various functional parts that can be grafted onto virus capsids. Such research endeavors will further expand and enable enhanced control over the functional capacity of these nanoscale devices for biomedicine. © 2014 Wiley Periodicals, Inc.

  7. Transcaval Access for TAVR Across a Polyester Aortic Graft

    Science.gov (United States)

    Lederman, Robert J.; O’Neill, William W.; Greenbaum, Adam B.

    2015-01-01

    Transcaval access to the aorta allows transcatheter aortic valve replacement in patients without other good access options. The resulting aortocaval fistula is closed with a nitinol cardiac occluder device. There is no experience traversing a synthetic aortic graft to perform transcaval access and closure. We describe a patient who underwent successful traversal of a polyester aortic graft using radiofrequency energy applied from the tip of a guidewire, to allow retrograde transcatheter aortic valve replacement from a femoral vein, along with details of our technique. The patient did well and was discharged home after 3 days. There was residual aortocaval fistulous flow immediately after implantation of a polyester-seeded nitinol muscular ventricular septal defect occluder device, but this fistula spontaneously occluded within one month. PMID:25510917

  8. Hypothenar hammer syndrome: long-term results of vascular reconstruction.

    Science.gov (United States)

    Endress, Ryan D; Johnson, Craig H; Bishop, Allen T; Shin, Alexander Y

    2015-04-01

    To evaluate long-term patency rates and related outcomes after vascular reconstruction of hypothenar hammer syndrome and identify patient- or treatment-related factors that may contribute to differences in outcome. We used color flow ultrasound to determine the patency of 18 vein graft reconstructions of the ulnar artery at the wrist in 16 patients. Validated questionnaires evaluated patients' functional disability with the Disabilities of the Arm, Shoulder, and Hand score, pain with the visual analog scale, and cold intolerance with the Cold Intolerance Symptom Severity survey. Patient demographics, clinical data, and surgical factors were analyzed for association with graft failure. Patients were asked to grade the result of treatment on a scale of 0 to 10. Of 18 grafts, 14 (78%) were occluded at a mean of 118 months postoperatively. Patients with patent grafts had significantly less disability related to cold intolerance according to the Cold Intolerance Symptom Severity survey in addition to significantly less pain on the visual analog scale. There was no statistical difference in Disabilities of the Arm, Shoulder, and Hand scores between patients with patent or occluded grafts. Patients graded the result significantly higher in patent reconstructions. We noted a higher incidence of graft occlusion than previously reported at a mean follow-up of 9.8 years, which represents a long-duration follow-up study of surgical treatment of hypothenar hammer syndrome. Despite a high percentage of occlusion, overall, patients remained satisfied with low functional disability and all would recommend surgical reconstruction. This study suggests that improved outcomes may result from patent grafts in the long term. Prognostic IV. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  9. Is Centrifugation Necessary for Processing Lipoaspirate Harvested via Water-Jet Force Assisted Technique before Grafting? Evidence of Lipoaspirate Concentration With Enhanced Fat Graft Survival.

    Science.gov (United States)

    Yin, Shilu; Luan, Jie; Fu, Su; Zhuang, Qiang

    2016-10-01

    Although water-jet force-assisted liposuction technique (WAL) was demonstrated to have favorable effects on fat grafting, controversy continues concerning the application of centrifugation for lipoaspirate harvested via WAL. As a controversial technique, plastic surgeons often get perplexed to the necessity of using centrifugation during fat grafting procedure. In the present study, we adopted the recommended centrifugal intensity (1200g, 3 minutes) to process lipoaspirate and focused on the influence of centrifugation on the fate of lipoaspirate harvested with WAL technique. Lipoaspirate was obtained from 10 healthy Chinese female patients who underwent cosmetic liposuction. The harvested lipoaspirate was either not centrifuged (group A) or centrifuged at 1200g for 3 minutes (group B). Lipoaspirate from each group was compared in the in vitro and in vivo experiments. The influence of centrifugation on lipoaspirate viability and lipoaspirate survival after grafting were evaluated. The viability of the lipoaspirates was similar between equally volumetric uncentrifugal and centrifugal lipoaspirate. However, centrifugation at 1200g for 3 minutes concentrated stromal vascular fraction cells and adipose-derived stem cells in lipoaspirate; greater angiogenesis and weight retention rates were observed in centrifugal lipoaspirate after grafting than those uncentrifugal lipoaspirate. Centrifugation at 1200g for 3 minutes enhanced the survival of lipoaspirate harvested via WAL technique after grafting. Centrifugation at 1200g for 3 minutes was recommended to process lipoaspirate harvested with water-jet force assistance before grafting.

  10. Pediatric vascular access

    International Nuclear Information System (INIS)

    Donaldson, James S.

    2006-01-01

    Pediatric interventional radiologists are ideally suited to provide vascular access services to children because of inherent safety advantages and higher success from using image-guided techniques. The performance of vascular access procedures has become routine at many adult interventional radiology practices, but this service is not as widely developed at pediatric institutions. Although interventional radiologists at some children's hospitals offer full-service vascular access, there is little or none at others. Developing and maintaining a pediatric vascular access service is a challenge. Interventionalists skilled in performing such procedures are limited at pediatric institutions, and institutional support from clerical staff, nursing staff, and technologists might not be sufficiently available to fulfill the needs of such a service. There must also be a strong commitment by all members of the team to support such a demanding service. There is a slippery slope of expected services that becomes steeper and steeper as the vascular access service grows. This review is intended primarily as general education for pediatric radiologists learning vascular access techniques. Additionally, the pediatric or adult interventional radiologist seeking to expand services might find helpful tips. The article also provides education for the diagnostic radiologist who routinely interprets radiographs containing vascular access devices. (orig.)

  11. Vascular Access in Children

    International Nuclear Information System (INIS)

    Krishnamurthy, Ganesh; Keller, Marc S.

    2011-01-01

    Establishment of stable vascular access is one of the essential and most challenging procedures in a pediatric hospital. Many clinical specialties provide vascular service in a pediatric hospital. At the top of the “expert procedural pyramid” is the pediatric interventional radiologist, who is best suited and trained to deliver this service. Growing awareness regarding the safety and high success rate of vascular access using image guidance has led to increased demand from clinicians to provide around-the-clock vascular access service by pediatric interventional radiologists. Hence, the success of a vascular access program, with the pediatric interventional radiologist as the key provider, is challenging, and a coordinated multidisciplinary team effort is essential for success. However, there are few dedicated pediatric interventional radiologists across the globe, and also only a couple of training programs exist for pediatric interventions. This article gives an overview of the technical aspects of pediatric vascular access and provides useful tips for obtaining vascular access in children safely and successfully using image guidance.

  12. Graft union formation in Douglas-fir.

    Science.gov (United States)

    D.L. Copes

    1969-01-01

    Greenhouse-grown Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) graft unions were examined between 2 and 84 days after grafting. Room temperature was maintained at 60-70 F throughout the growing season. In most respects grafts of Douglas-fir followed development patterns previously reported for spruce and pine grafts, but specific differences...

  13. Grafting compatibility between selected rootstocks and Tanzanian ...

    African Journals Online (AJOL)

    The grafted seedlings with graft union tied using grafting clips were healed in a dark chamber for three days and then in a transparent chamber for three days. The average temperature and relative humidity in both chambers were maintained at 21-30°C and 85-95 %, respectively. The grafted seedlings were hardened for ...

  14. Synthetic biological networks

    International Nuclear Information System (INIS)

    Archer, Eric; Süel, Gürol M

    2013-01-01

    Despite their obvious relationship and overlap, the field of physics is blessed with many insightful laws, while such laws are sadly absent in biology. Here we aim to discuss how the rise of a more recent field known as synthetic biology may allow us to more directly test hypotheses regarding the possible design principles of natural biological networks and systems. In particular, this review focuses on synthetic gene regulatory networks engineered to perform specific functions or exhibit particular dynamic behaviors. Advances in synthetic biology may set the stage to uncover the relationship of potential biological principles to those developed in physics. (review article)

  15. Synthetic Base Fluids

    Science.gov (United States)

    Brown, M.; Fotheringham, J. D.; Hoyes, T. J.; Mortier, R. M.; Orszulik, S. T.; Randles, S. J.; Stroud, P. M.

    The chemical nature and technology of the main synthetic lubricant base fluids is described, covering polyalphaolefins, alkylated aromatics, gas-to-liquid (GTL) base fluids, polybutenes, aliphatic diesters, polyolesters, polyalkylene glycols or PAGs and phosphate esters.Other synthetic lubricant base oils such as the silicones, borate esters, perfluoroethers and polyphenylene ethers are considered to have restricted applications due to either high cost or performance limitations and are not considered here.Each of the main synthetic base fluids is described for their chemical and physical properties, manufacture and production, their chemistry, key properties, applications and their implications when used in the environment.

  16. Synthesis and Properties of Carbon Nanotube-Grafted Silica Nanoarchitecture-Reinforced Poly(Lactic Acid

    Directory of Open Access Journals (Sweden)

    Yao-Wen Hsu

    2017-07-01

    Full Text Available A novel nanoarchitecture-reinforced poly(lactic acid (PLA nanocomposite was prepared using multi-walled carbon nanotube (MWCNT-grafted silica nanohybrids as reinforcements. MWCNT-grafted silica nanohybrids were synthesized by the generation of silica nanoparticles on the MWCNT surface through the sol-gel technique. This synthetic method involves organo-modified MWCNTs that are dispersed in tetrahydrofuran, which incorporates tetraethoxysilane that undergoes an ultrasonic sol-gel process. Gelation yielded highly dispersed silica on the organo-modified MWCNTs. The structure and properties of the nanohybrids were established using 29Si nuclear magnetic resonance, Raman spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis, and transmission electron microscopy. The resulting MWCNT nanoarchitectures were covalently assembled into silica nanoparticles, which exhibited specific and controllable morphologies and were used to reinforce biodegradable PLA. The tensile strength and the heat deflection temperature (HDT of the PLA/MWCNT-grafted silica nanocomposites increased when the MWCNT-grafted silica was applied to the PLA matrix; by contrast, the surface resistivity of the PLA/MWCNT-grafted silica nanocomposites appeared to decline as the amount of MWCNT-grafted silica in the PLA matrix increased. Overall, the reinforcement of PLA using MWCNT-grafted silica nanoarchitectures was efficient and improved its mechanical properties, heat resistance, and electrical resistivity.

  17. Hydrophobic surface functionalization of lignocellulosic jute fabrics by enzymatic grafting of octadecylamine.

    Science.gov (United States)

    Dong, Aixue; Fan, Xuerong; Wang, Qiang; Yu, Yuanyuan; Cavaco-Paulo, Artur

    2015-08-01

    Enzymatic grafting of synthetic molecules onto lignins provides a mild and eco-friendly alternative for the functionalization of lignocellulosic materials. In this study, laccase-mediated grafting of octadecylamine (OA) onto lignin-rich jute fabrics was investigated for enhancing the surface hydrophobicity. First, the lignins in jute fabrics were isolated and analyzed in the macromolecular level by MALDI-TOF MS, (1)H NMR, (13)C NMR, and HSQC-NMR. Then, the surface of jute fabrics was characterized by FT-IR, XPS, and SEM. Subsequently, the nitrogen content of jute fabrics was determined by the micro-Kjeldahl method, and the grafting percentage (Gp) and grafting efficiency (GE) of the enzymatic reaction were calculated. Finally, the surface hydrophobicity of the jute fabrics was estimated by contact angle and wetting time measurements. The results indicate that the OA monomers were successfully grafted onto the lignin moieties on the jute fiber surface by laccase with Gp and GE values of 0.712% and 10.571%, respectively. Moreover, the modified jute fabrics via OA-grafting showed an increased wetting time of 18.5 min and a contact angle of 116.72°, indicating that the surface hydrophobicity of the jute fabrics increased after the enzymatic grafting modification with hydrophobic OA molecules. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Vascular malformations in pediatrics

    International Nuclear Information System (INIS)

    Reith, W.; Shamdeen, M.G.

    2003-01-01

    Vascular malformations are the cause of nearly all non-traumatic intracranial hemorrhage in children beyond the neonatal stage. Therefore, any child presenting with spontaneous intracranial hemorrhage should be evaluated for child abuse and for vascular malformations. Intracerebral malformations of the cerebral vasculature include vein of Galen malformations, arteriovenous malformation (AVM), cavernomas, dural arteriovenous fistulas, venous anomalies (DVA), and capillary teleangiectasies. Although a few familial vascular malformation have been reported, the majority are sporadic. Clinical symptoms, diagnostic and therapeutic options are discussed. (orig.) [de

  19. Saphenous vein graft vs. radial artery graft searching for the best second coronary artery bypass graft

    Science.gov (United States)

    Al-Sabti, Hilal Ali; Al Kindi, Adil; Al-Rasadi, Khalid; Banerjee, Yajnavalka; Al-Hashmi, Khamis; Al-Hinai, Ali

    2013-01-01

    Coronary artery bypass grafting (CABG) was first used in the late 1960s. This revolutionary procedure created hope among ischemic heart disease patients. Multiple conduits are used and the golden standard is the left internal mammary artery to the left anterior descending artery. Although all approaches were advocated by doctors, the use of saphenous vein grafts became the leading approach used by the majority of cardiac surgeons in the 1970s. The radial artery graft was introduced at the same time but was not as prevalent due to complications. It was reintroduced into clinical practice in 1989. The procedure was not well received initially but it has since shown superiority in patency as well as long-term survival after CABG. This review provides a summary of characteristics, technical features and patency rates of the radial artery graft in comparison with venous conduits. Current studies and research into radial artery grafts and saphenous vein grafts for CABG are explored. However, more studies are required to verify the various findings of the positive effects of coronary artery bypass grafting with the help of radial arteries on mortality and long-lasting patency. PMID:24198449

  20. [Skin defect coverage with micro skin graft].

    Science.gov (United States)

    Gümüş, Nazim; Kaya, Yalçin; Karakaya, Sadik; Camci, Cemalettin

    2002-04-01

    The aim of this study is to coverage of the large skin defect with microskin graft. The wound coverage of the large skin defect may be difficult with auto skin graft. In these patients, split thickness skin graft may be used in a bloc shape or expanded skin graft shape and a stamp skin graft shape or expanded stamp skin graft shape. On the other hand, split thickness skin graft may be used as a micrograft shape after the mincing process, which reduces of the graft size in a few millimeters. In this study, 6 patients with skin defect was admitted in our clinic, and their skin defect was treated with micro skin graft. Expansion ratio was 1:15. Epithelialization on the wound surface was completed in 4 to 6 weeks and cobblestone appearance was observed after the wound coverage. Skin defect coverage with micrograft is an effective technique like the other skin graft coverage methods.

  1. Synthetic Biological Membrane (SBM)

    Data.gov (United States)

    National Aeronautics and Space Administration — The ultimate goal of the Synthetic Biological Membrane project is to develop a new type of membrane that will enable the wastewater treatment system required on...

  2. Synthesis and characterization of polypyrrole grafted chitin

    Science.gov (United States)

    Ramaprasad, A. T.; Latha, D.; Rao, Vijayalakshmi

    2017-05-01

    Synthesis and characterization of chitin grafted with polypyrrole (PPy) is reported in this paper. Chitin is soaked in pyrrole solution of various concentrations for different time intervals and polymerized using ammonium peroxy disulphate (APS) as an initiator. Grafting percentage of polypyrrole onto chitin is calculated from weight of chitin before and after grafting. Grafting of polymer is further verified by dissolution studies. The grafted polymer samples are characterized by FTIR, UV-Vis absorption spectrum, XRD, DSC, TGA, AFM, SEM and conductivity studies.

  3. Nonfunctioning Renal Allograft Embolization as an Alternative to Graft Nephrectomy: Report on Seven Years' Experience

    International Nuclear Information System (INIS)

    Atar, Eli; Belenky, Alexander; Neuman-Levin, Margalit; Yussim, A.; Bar-Nathan, Nathan; Bachar, Gil N.

    2003-01-01

    Purpose: Graft nephrectomy is the treatment of choice in patients with graft intolerance syndrome, but it is associated with high morbidity and mortality rates. Renal vascular embolization has been suggested as a possible alternative. The aim of this study was to evaluate the efficacy and safety of arterial embolization of these nonfunctioning transplanted kidneys. Methods: Twenty-six transplanted kidneys in 25 patients with irreversible renal graft rejection and graft intolerance who underwent arterial embolization at our center from August 1994 to April 2001 we reanalyzed for procedural success and long-term outcome. Embolization was performed with absolute alcohol or with polyvinyl alcohol (Ivalon) and coils. Results: Twenty-four of the 26 (92%) procedures were technically successful, but in one patient only partial occlusion of one of two renal arteries was achieved, and in another the renal artery was already completely occluded. There were two major complications: emphysematous pyelonephritis necessitating nephrectomy and groin abscess that was drained. Follow-up ranged from 8 to 84 months. Clinical success was achieved in 24 of the 26 procedures(92%), and only in one patient did embolization fail to relieve the symptoms, and nephrectomy was performed 3 months later. Conclusion: Renal vascular embolization is a simple, safe and effective technique for the treatment of nonfunctioning renal allografts associated with graft intolerance syndrome. We suggest that it be considered the treatment of choice

  4. Native Coronary and Bypass Graft Cannulation Through Transradial Approach: Technical Considerations.

    Science.gov (United States)

    Patel, Tejas; Shah, Sanjay; Pancholy, Samir; Deora, Surender; Kwan, Tak; Gilchrist, Ian C

    2015-09-01

    The aim of this review is to discuss different methods using the transradial approach (TRA) of accessing the native coronary arteries and bypass grafts to optimize the quality of angiographic results and support for interventional procedures. Successful coronary cannulation provides the basis for optimal angiography and interventional success. There is limited literature describing successful transradial techniques of coronary and bypass graft cannulation. In this review, a variety of different challenges and their solutions are provided. Successful TRA methods for routine cannulation and modified methods for challenging cannulation of both native coronaries and bypass grafts are described based on the experience of several high-volume radial operators. Differences in catheter/vascular lumen interactions endow different operating characteristics to catheters depending on whether the femoral or either radial approach is used. Understanding these differences contributes to success in TRA. In addition, techniques for cannulation of anomalous coronary origin, use of special catheter curves, small and large lumen guide catheters, sheathless guide catheters, universal catheters, and a special technique to cannulate the internal mammary artery from the contralateral radial artery are reviewed, with supporting figures. Despite lower bleeding and vascular complication rates as compared with transfemoral approach (TFA), the adoption of TRA has been relatively slow, particularly with cases of complex anatomy such as bypass graft cannulation. Anatomical challenges at various levels of the catheter course play an important role in TRA coronary and bypass graft cannulation failure. A logical approach and understanding of these challenges can augment procedural success and enhance quality.

  5. Hybridization with synthetic oligonucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Szostak, J.W.; Stiles, J.I.; Tye, B.K.; Sherman, F.; Wu, R.

    1978-01-01

    Procedures are described for the use of synthetic oligonucleotides for Southern blot experiments and gene bank screening, and the effect of various mismatches on the efficiency of hybridization is demonstrated. The following topics are discussed: sensitivity vs. specificity, hybridization of a 12-mer to the lambda endolysin gene; hybridization of oligonucleotide probes to the E. coli lac operator; hybridization of synthetic probes to the CYC1 gene of yeast; and cloning eucaryotic genes. (HLW)

  6. Mammalian Synthetic Biology

    OpenAIRE

    Martella, Andrea; Pollard, Steven M; Dai, Junbiao; Cai, Yizhi

    2016-01-01

    The enabling technologies of synthetic biology are opening up new opportunities for engineering and enhancement of mammalian cells. This will stimulate diverse applications in many life science sectors such as regenerative medicine, development of biosensing cell lines, therapeutic protein production, and generation of new synthetic genetic regulatory circuits. Harnessing the full potential of these new engineering-based approaches requires the design and assembly of large DNA constructs-pote...

  7. Implantation of decellularized small-caliber vascular xenografts with and without surface heparin treatment

    NARCIS (Netherlands)

    Wang, Xue-Ning; Chen, Chang-Zhi; Yang, Min; Gu, Y. John

    Heparin treatment of decellularized xenografts has been reported to reduce graft thrombogenicity. However, little is known about the in vivo comparison of heparin-treated with non-heparin-treated xenografts, especially for small-caliber vascular implants. We implanted either a heparin-treated or a

  8. Congenital Vascular Malformation

    Science.gov (United States)

    ... surgery or less invasive therapy of the enlarged superficial veins can also be helpful. T he V ascular D isease F oundation Established in 1998, t he Vascular Disease Foundation (VDF) develops educational information and initiatives for patients, ...

  9. Uterine Vascular Lesions

    Science.gov (United States)

    Vijayakumar, Abhishek; Srinivas, Amruthashree; Chandrashekar, Babitha Moogali; Vijayakumar, Avinash

    2013-01-01

    Vascular lesions of the uterus are rare; most reported in the literature are arteriovenous malformations (AVMs). Uterine AVMs can be congenital or acquired. In recent years, there has been an increasing number of reports of acquired vascular lesions of the uterus following pregnancy, abortion, cesarean delivery, and curettage. It can be seen from these reports that there is confusion concerning the terminology of uterine vascular lesions. There is also a lack of diagnostic criteria and management guidelines, which has led to an increased number of unnecessary invasive procedures (eg, angiography, uterine artery embolization, hysterectomy for abnormal vaginal bleeding). This article familiarizes readers with various vascular lesions of the uterus and their management. PMID:24340126

  10. Heart and vascular services

    Science.gov (United States)

    ... maintain body temperature, among other things. CARDIOVASCULAR MEDICINE Cardiovascular medicine refers to the branch of health care that specializes in the treatment of diseases or conditions dealing with the heart and vascular systems. Common ...

  11. Vascular Access Procedures

    Science.gov (United States)

    ... vascular access catheters: A peripherally inserted central catheter (PICC) is a long catheter that extends from an ... central catheter may be larger caliber than a PICC, and is designed to be placed via a ...

  12. Bioactive coating with low-fouling polymers for the development of biocompatible vascular implants

    Science.gov (United States)

    Thalla, Pradeep Kumar

    The replacement of occluded blood vessels and endovascular aneurysm repair (EVAR) are performed with the use of synthetic vascular grafts and stent grafts, respectively. Both implants lead to frequent clinical complications that are different but due to a similar problem, namely the inadequate surface properties of the polymeric biomaterials used (generally polyethylene terephthalate (PET) or expanded polytetrafluoroethylene (ePTFE)). Therefore the general objective of this thesis was to create a versatile bioactive coating on vascular biomaterials that reduce material-induced thrombosis and promote desired cell interactions favorable to tissue healing around implants. The use of low-fouling backgrounds was decided in order to reduce platelet adhesion as well as the non-specific protein adsorption and thus increase the bioactivity of immobilized biomolecules. As part of the preliminary objective, a multi-arm polyethylene glycol (PEG) was chosen to create a versatile low-fouling surface, since the current coating methods are far from being versatile and rely on the availability of compatible functional groups on both PEG and the host surface. This PEG coating method was developed by taking advantage of novel primary amine-rich plasma polymerized coatings (LP). As demonstrated by quartz crystal microbalance with dissipation (QCM-D), fluorescence measurements and platelet adhesion assays, our PEG coatings exhibited low protein adsorption and almost no platelet adhesion after 15 min perfusion in whole blood. Although protein adsorption was not completely abrogated and short-term platelet adhesion assay was clearly insufficient to draw conclusions for long-term prevention of thrombosis in vivo, the low-fouling properties of this PEG coating were sufficient to be exploited for further coupling of bioactive molecules to create bioactive coatings. Therefore, as a part of the second objective, an innovative and versatile bioactive coating was developed on PEG and

  13. Bone Grafting: Sourcing, Timing, Strategies, and Alternatives.

    Science.gov (United States)

    Egol, Kenneth A; Nauth, Aaron; Lee, Mark; Pape, Hans-Christoph; Watson, J Tracy; Borrelli, Joseph

    2015-12-01

    Acute fractures, nonunions, and nonunions with bone defects or osteomyelitis often need bone graft to facilitate union. There are several factors to consider when it is determined that a bone graft is needed. These factors include the source of the bone graft (autograft vs. allograft), proper timing for placement of the bone graft, strategies to avoid further complications (particularly in the setting of osteomyelitis), and with the development of a variety of bone graft substitutes, whether alternatives to autograft are available and appropriate for the task at hand. Autograft bone has commonly been referred to as the "gold standard" of bone grafts, against which the efficacy of other grafts has been measured. The best timing for when to place a bone graft or substitute is also somewhat controversial, particularly after an open fracture or a potentially contaminated bed. The treatment of infected nonunions, particularly those that require a graft to facilitate healing, can be quite challenging. Typically, the infection is completely eradicated before placement of a bone graft, but achieving a sterile bed and the timing of a bone graft require strategic thinking and planning. This review outlines the benefits of autografts, the most suitable sites for harvesting bone grafts, the timing of bone graft procedures, the potential risks and benefits of grafting in the face of infection, and the currently available bone graft extenders.

  14. Air Pump-Assisted Graft Centration, Graft Edge Unfolding, and Graft Uncreasing in Young Donor Graft Pre-Descemet Endothelial Keratoplasty.

    Science.gov (United States)

    Jacob, Soosan; Narasimhan, Smita; Agarwal, Amar; Agarwal, Athiya; A I, Saijimol

    2017-08-01

    To assess an air pump-assisted technique for graft centration, graft edge unfolding, and graft uncreasing while performing pre-Descemet endothelial keratoplasty (PDEK) using young donor grafts. Continuous pressurized air infusion was used for graft centration, graft edge unfolding, and graft unwrinkling. Ten eyes of 10 patients underwent PDEK with donors aged below 40 years. In all eyes, the donor scrolled into tight scrolls. In all cases, the air pump-assisted technique was effective in positioning and centering the graft accurately and in straightening infolded graft edges and smoothing out graft creases and wrinkles. Endothelial cell loss was 38.6%. Postoperative best-corrected visual acuity at 6 months was 0.66 ± 0.25 in decimal equivalent. Continuous pressurized air infusion acted as a third hand providing a continuous pressure head that supported the graft and prevented graft dislocation as well as anterior chamber collapse during intraocular maneuvering. Adequate maneuvering space was available in all cases, and bleeding, if any, was tamponaded successfully in all cases. Although very young donor grafts may be used for PDEK, they are difficult to center and