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Sample records for eptfe vascular grafts

  1. Novel phosphate-grafted ePTFE copolymers for optimum in vitro mineralization

    International Nuclear Information System (INIS)

    Wentrup-Byrne, Edeline; Suzuki, Shuko; Groendahl, Lisbeth; Suwanasilp, Juthakarn Jessica

    2010-01-01

    Surface modification via graft copolymerization is an attractive method for optimizing polymers used in biomedical applications. We developed a novel method using a mixed solvent system (either water and dichloromethane (DCM) or water, methanol and DCM) consisting of two solvent phases for grafting 2-(methacryloyloxy)ethyl phosphate onto expanded polytetrafluoroethylene (ePTFE). This new method resulted in the fabrication of grafted membranes with greater grafting extents (GEs) (as evaluated from x-ray photoelectron spectroscopy (XPS)) in the organic phase than those obtained when grafting was carried out in a single phase. It also made it possible to graft in the aqueous phase, a process that is otherwise inhibited by the concomitant formation of large amounts of highly crystalline homopolymer. Thorough characterization of the grafted membranes using gravimetric, XPS and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) not only permitted evaluation of the grafting outcomes but also made it possible to analyze their dependence on monomer concentration and solvent composition. A selection of membranes was tested for their in vitro mineralization capacity using simulated body fluid. It was found that an 'ideal' mineralization outcome, i.e. a uniform coating of carbonated hydroxyapatite (cHAP) formed on the sample grafted in the aqueous phase of the water/DCM two-phase solvent system. A detailed discussion bringing together these results, as well as results from a series of earlier studies, allows conclusions regarding polymer chemistry and the topology necessary for cHAP mineralization.

  2. Analysis of explanted ePTFE cardiovascular grafts (modified BT shunt)

    Energy Technology Data Exchange (ETDEWEB)

    Doble, Mukesh [Department of Biotechnology, Indian Institute of Technology, Chennai 600 036 (India); Makadia, Nilesh; Pavithran, Sreeja; Kumar, R Suresh [Department of Pediatric Cardiology, Institute of Cardio-Vascular Diseases, Madras Medical Mission, Chennai, 600 037 (India)], E-mail: mukeshd@iitm.ac.in

    2008-09-01

    Structural, chemical, mechanical and surface changes were studied in expanded polytetrafluroethylene vascular grafts explanted from children undergoing planned surgical management of congenital heart disease. These grafts were implanted when recipients were aged 7 days to 8 years (median-48 weeks) and they had been in circulation for a period of 10-52 months (median-74 weeks). While no chemical changes were observed in the shunt, on average the tensile strength had decreased by 50%, total elongation by 61% and crystallinity by 3%. No salt deposits were observed on the surface of the graft. Soluble and insoluble proteins were bound to the polymer surface, which had made the surface hydrophilic. The external surface roughness had increased by 254.5 and the internal surface roughness by 2.6 times the initial value. The fine polymer structure had become fused and clumped. The fusing of strands on the polymer surface became more pronounced with longer duration of implantation. In one instance of previously documented graft stenosis, the heat capacity was found to be more than that of the unimplanted sample, indicating an increase in crystallinity. A longer period of study with a larger sample size would likely shed more light on the relation between physico-chemical changes and graft stenosis.

  3. Analysis of explanted ePTFE cardiovascular grafts (modified BT shunt)

    International Nuclear Information System (INIS)

    Doble, Mukesh; Makadia, Nilesh; Pavithran, Sreeja; Kumar, R Suresh

    2008-01-01

    Structural, chemical, mechanical and surface changes were studied in expanded polytetrafluroethylene vascular grafts explanted from children undergoing planned surgical management of congenital heart disease. These grafts were implanted when recipients were aged 7 days to 8 years (median-48 weeks) and they had been in circulation for a period of 10-52 months (median-74 weeks). While no chemical changes were observed in the shunt, on average the tensile strength had decreased by 50%, total elongation by 61% and crystallinity by 3%. No salt deposits were observed on the surface of the graft. Soluble and insoluble proteins were bound to the polymer surface, which had made the surface hydrophilic. The external surface roughness had increased by 254.5 and the internal surface roughness by 2.6 times the initial value. The fine polymer structure had become fused and clumped. The fusing of strands on the polymer surface became more pronounced with longer duration of implantation. In one instance of previously documented graft stenosis, the heat capacity was found to be more than that of the unimplanted sample, indicating an increase in crystallinity. A longer period of study with a larger sample size would likely shed more light on the relation between physico-chemical changes and graft stenosis

  4. Vascular graft infections with Mycoplasma

    DEFF Research Database (Denmark)

    Levi-Mazloum, Niels Donald; Skov Jensen, J; Prag, J

    1995-01-01

    laboratory techniques, the percentage of culture-negative yet grossly infected vascular grafts seems to be increasing and is not adequately explained by the prior use of antibiotics. We have recently reported the first case of aortic graft infection with Mycoplasma. We therefore suggest the hypothesis...... that the large number of culture-negative yet grossly infected vascular grafts may be due to Mycoplasma infection not detected with conventional laboratory technique....

  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. Postoperative radiographic evaluation of vascularized fibular grafts

    International Nuclear Information System (INIS)

    Manaster, B.J.; Coleman, D.A.; Bell, D.A.

    1989-01-01

    This paper reports on thirty-five patients with free vascularized fibular grafts examined postoperatively with plain radiography. Early graft incorporation is seen as a fuzziness of the cortex at the site of its insertion into the host bone. Causes of failure in grafting for bone defects include graft fracture, hardware failure, and infection. A high percentage of complications or at least delayed unions occurred when vascularized fibular grafts were used to fill defects in the lower extremity. Conversely, upper extremity defects bridged by vascularized grafts heal quickly and hypertrophy. Vascularized grafts placed in the femoral head and neck for a vascular necrosis incorporate early on their superior aspect. The osseous tunnel in which they are placed is normally wider than the graft and often becomes sclerotic; this appearance does not represent nonunion

  7. Hemodynamic effects of spiral ePTFE prosthesis compared with standard arteriovenous graft in a carotid to jugular vein porcine model.

    Science.gov (United States)

    Jahrome, Ommid K; Hoefer, Imo; Houston, Graeme J; Stonebridge, Peter A; Blankestijn, Peter J; Moll, Frans L; de Borst, Gert J

    2011-01-01

    The primary patency rate of arteriovenous (AV) grafts is limited by distal venous anastomosis stenosis or occlusion due to intimal hyperplasia associated with distal graft turbulence. The normal blood flow in native arteries is spiral laminar flow. Standard vascular grafts do not produce spiral laminar flow at the distal anastomosis. Vascular grafts which induce a spiral laminar flow distally result in lower turbulence, particularly near the vessel wall. This initial study compares the hemodynamic effects of a spiral flow-inducing graft and a standard graft in a new AV carotid to jugular vein crossover graft porcine model. Four spiral flow grafts and 4 control grafts were implanted from the carotid artery to the contralateral jugular vein in 4 pigs. Two animals were terminated after 48 hours and 2 at 14 days. Graft patency was assessed by selective catheter digital angiography, and the flow pattern was assessed by intraoperative flow probe and color Doppler ultrasound (CDU) measurements. The spiral grafts were also assessed at enhanced flow rates using an external roller pump to simulate increased flow rates that may occur during dialysis using a standard dialysis needle cannulation. The method increased the flow rate through the graft by 660 ml/min. The graft distal anastomotic appearances were evaluated by explant histopathology. All grafts were patent at explantation with no complications. All anastomoses were found to be wide open and showed no significant angiographic stenosis at the distal anastomosis in both spiral and control grafts. CDU examinations showed a spiral flow pattern in the spiral graft and double helix pattern in the control graft. No gross histopathological effects were seen in either spiral or control grafts. This porcine model is robust and allows hemodynamic flow assessment up to 14 days postimplantation. The spiral flow-inducing grafts produced and maintained spiral flow at baseline and enhanced flow rates during dialysis needle

  8. Grafted functional groups on expanded tetrafluoroethylene (ePTFE) support for fuel cell and water transport membranes

    Science.gov (United States)

    Fuller, Timothy J.; Jiang, Ruichun

    2017-01-24

    A method for forming a modified solid polymer includes a step of contacting a solid fluorinated polymer with a sodium sodium-naphthalenide solution to form a treated fluorinated solid polymer. The treated fluorinated solid polymer is contacted with carbon dioxide, sulfur dioxide, or sulfur trioxide to form a solid grafted fluorinated polymer. Characteristically, the grafted fluorinated polymer includes appended CO.sub.2H or SO.sub.2H or SO.sub.3H groups. The solid grafted fluorinated polymer is advantageously incorporated into a fuel cell as part of the ion-conducting membrane or a water transport membrane in a humidifier.

  9. [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.

  10. 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.

  11. 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)

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

    DEFF Research Database (Denmark)

    Gao, H; Sandermann, J; Prag, J

    2010-01-01

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

  13. 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.

  14. Autogenous bone graft and ePTFE membrane in the treatment of peri-implantitis. II. Stereologic and histologic observations in cynomolgus monkeys

    DEFF Research Database (Denmark)

    Schou, Søren; Holmstrup, Palle; Skovgaard, Lene Theil

    2003-01-01

    autogenous bone graft; guided bone regeneration; histology; membrane; non-human primates; oral implants; osseointegration; pathalogy; peri-implantitis; stereology; treatment......autogenous bone graft; guided bone regeneration; histology; membrane; non-human primates; oral implants; osseointegration; pathalogy; peri-implantitis; stereology; treatment...

  15. 3D-Printed Biodegradable Polymeric Vascular Grafts.

    Science.gov (United States)

    Melchiorri, A J; Hibino, N; Best, C A; Yi, T; Lee, Y U; Kraynak, C A; Kimerer, L K; Krieger, A; Kim, P; Breuer, C K; Fisher, J P

    2016-02-04

    Congenital heart defect interventions may benefit from the fabrication of patient-specific vascular grafts because of the wide array of anatomies present in children with cardiovascular defects. 3D printing is used to establish a platform for the production of custom vascular grafts, which are biodegradable, mechanically compatible with vascular tissues, and support neotissue formation and growth. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. 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.

  17. Salmonella Typhimurium gastroenteritis leading to chronic prosthetic vascular graft infection.

    Science.gov (United States)

    Cullinan, Milo; Clarke, Michael; Dallman, Tim; Peart, Steven; Wilson, Deborah; Weiand, Daniel

    2017-08-01

    Introduction. It is estimated up to 6 % of prosthetic vascular grafts become infected. Staphylococcus aureus is predominant in early infection and coagulase-negative staphylococci are predominant in late infections. Enterobacteriaceae cause 14-40 % of prosthetic vascular graft infections. This is, to our knowledge the first reported case of Salmonella gastroenteritis causing chronic prosthetic vascular graft infection (PVGI). Case presentation. A 57 years old lady presented with signs and symptoms of prosthetic vascular graft infection. Three years earlier, she had undergone a prosthetic axillo-femoral bypass graft for critical limb ischaemia. The infected prosthetic vascular graft was removed and Salmonella Typhimurium was isolated on culture. In the intervening period, Salmonella Typhimurium was isolated from a faecal specimen, collected during an episode of acute gastroenteritis. Whole-genome sequencing (WGS) showed that the respective Salmonella Typhimurium isolates differed by only a single nucleotide polymorphism (SNP). Salmonella Typhimurium was not isolated on culture of a faecal specimen collected five days following cessation of antimicrobial therapy. Six months after removal of the prosthetic graft, the patient remains under follow-up for her peripheral vascular disease, which currently requires no further surgical intervention. Conclusion. This case has clear implications for the management of chronic PVGI. It is vital to collect high-quality surgical specimens for microbiological analysis and empirical choices of antibiotics are unlikely to cover all potential pathogens. It may also be prudent to enquire about a history of acute gastroenteritis when assessing patients presenting with chronic PVGI.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-27

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

  19. 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.

  20. 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.

  1. 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

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

    Science.gov (United States)

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

    2008-04-01

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

  3. Bacterial adherence to vascular grafts after in vitro bacteremia

    International Nuclear Information System (INIS)

    Rosenman, J.E.; Pearce, W.H.; Kempczinski, R.F.

    1985-01-01

    All currently used arterial prosthetics have a greater susceptibility to infection following bacteremia than does autogenous tissue. This experiment compares quantitative bacterial adherence to various prosthetic materials after bacteremia carried out in a tightly controlled and quantitative fashion. Ten centimeters long, 4 mm i.d. Dacron, umbilical vein (HUV), and polytetrafluoroethylene (PTFE) grafts, as well as PTFE grafts with a running suture line at the midportion were tested. Each graft was interposed into a pulsatile perfusion system modified from a Waters MOX 100 TM renal transplant pump. Indium-111-labeled Staphylococcus aureus were added to heparinized canine blood to give a mean concentration of 4.7 X 10(6) bacteria/cc. This infected blood was recirculated through each graft for 30 min at a rate of 125 cc/m, 100 Torr (sys), 60 beats/min. The gamma counts/graft were used to calculate the number of bacteria/cm2 of graft surface. After nine experiments, a mean of 9.63 X 10(5) bacteria/cm2 were adherent to the Dacron, 1.04 X 10(5) bacteria/cm2 to the HUV, and 2.15 X 10(4) bacteria/cm2 to the PTFE. These differences were all significant at the 0.05 level. The addition of a suture line increased bacterial adherence to the PTFE graft by 50%. These results suggest that PTFE is the vascular graft material of choice when a prosthetic graft must be implanted despite a high risk of subsequent clinical bacteremia. An in vitro, pulsatile perfusion model gave accurate and reproducible results, and appears well suited for further studies of bacterial, or platelet adherence to grafts, as well as the biomechanics of vascular conduits

  4. 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

  5. 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.

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

    Science.gov (United States)

    Chan, Alex H P; Tan, Richard P; Michael, Praveesuda L; Lee, Bob S L; Vanags, Laura Z; Ng, Martin K C; Bursill, Christina A; Wise, Steven G

    2017-01-01

    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.

  7. 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.

  8. Electrospun polydioxanone-elastin blends: potential for bioresorbable vascular grafts

    Energy Technology Data Exchange (ETDEWEB)

    Sell, S A [Virginia Commonwealth University, Richmond, VA 23298 (United States); McClure, M J [Virginia Commonwealth University, Richmond, VA 23298 (United States); Barnes, C P [Virginia Commonwealth University, Richmond, VA 23298 (United States); Knapp, D C [Virginia Commonwealth University, Richmond, VA 23298 (United States); Walpoth, B H [University Hospital, 1211 Geneva 14 (Switzerland); Simpson, D G [Virginia Commonwealth University, Richmond, VA 23298 (United States); Bowlin, G L [Virginia Commonwealth University, Richmond, VA 23298 (United States)

    2006-06-15

    An electrospun cardiovascular graft composed of polydioxanone (PDO) and elastin has been designed and fabricated with mechanical properties to more closely match those of native arterial tissue, while remaining conducive to tissue regeneration. PDO was chosen to provide mechanical integrity to the prosthetic, while elastin provides elasticity and bioactivity (to promote regeneration in vitro/in situ). It is the elastic nature of elastin that dominates the low-strain mechanical response of the vessel to blood flow and prevents pulsatile energy from being dissipated as heat. Uniaxial tensile and suture retention tests were performed on the electrospun grafts to demonstrate the similarities of the mechanical properties between the grafts and native vessel. Dynamic compliance measurements produced values that ranged from 1.2 to 5.6%/100 mmHg for a set of three different mean arterial pressures. Results showed the 50:50 ratio to closely mimic the compliance of native femoral artery, while grafts that contained less elastin exceeded the suture retention strength of native vessel. Preliminary cell culture studies showed the elastin-containing grafts to be bioactive as cells migrated through their full thickness within 7 days, but failed to migrate into pure PDO scaffolds. Electrospinning of the PDO and elastin-blended composite into a conduit for use as a small diameter vascular graft has extreme potential and warrants further investigation as it thus far compares favorably to native vessel.

  9. 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.

  10. Engineering based assessment for a shape design of a pediatric ePTFE pulmonary conduit valve.

    Science.gov (United States)

    Tsuboko, Yusuke; Shiraishi, Yasuyuki; Yamada, Akihiro; Yambe, Tomoyuki; Miura, Hidekazu; Mura, Seitaro; Yamagishi, Masaaki

    2016-08-01

    The authors examined the hemodynamic characteristics of expanded polytetrafluoroethylene (ePTFE) pulmonary valved conduits quantitatively by our originally developed pediatric pulmonary mechanical circulatory system, in order to suggest the optimal shape design. The system consisted of pneumatically driven right atrium and ventricle model, a pulmonary valve chamber, and elastic pulmonary compliance model with peripheral vascular resistance units, a venous reservoir. We employed two different types of ePTFE valve and evaluated the relationship between the leaflets motion and hemodynamic characteristics by using a high-speed video camera. As a result, we successfully reproduced hemodynamic simulations in our pediatric pulmonary mock system. We confirmed that the presence of bulging sinuses in the pulmonary valved conduit reduced the transvalvular energy loss and increased the valve opening area during systolic period. Our engineering-based in vitro analysis could be useful for proposing a shape design optimization of sophisticated pediatric ePTFE pulmonary valve.

  11. 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.

  12. 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.

  13. Ankle and pantalar arthrodeses using vascularized fibular grafts.

    Science.gov (United States)

    Yajima, Hiroshi; Kobata, Yasunori; Tomita, Yasuharu; Kawate, Kenji; Sugimoto, Kazuya; Takakura, Yoshinori

    2004-01-01

    From 1989 to 1998 ankle and pantalar arthrodeses using vascularized fibular grafts were performed for seven patients. The indications for surgery were chronic nonunion following fracture of the distal tibia in four patients, rheumatoid arthritis in two, and talus necrosis in one. The ankle joint was fused in the two patients with a pilon fracture, and in the other five patients, both the ankle and subtalar joints were fused. In one patient, additional bone grafting was required for delayed union. In the other six patients, the mean period required to obtain radiographic bone union was 6 months (range, 4-9 months). The time until the patients could walk without braces ranged from 6 to 20 months (mean, 12.3 months). Local infection was not encountered in any patients. This procedure represents a viable option for patients in whom a standard, less complicated arthrodesis cannot be performed.

  14. 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)

  15. Porcine carotid artery replacement with biodegradable electrospun poly-e-caprolactone vascular prosthesis.

    Science.gov (United States)

    Mrówczyński, Wojciech; Mugnai, Damiano; de Valence, Sarra; Tille, Jean-Christophe; Khabiri, Ebrahim; Cikirikcioglu, Mustafa; Möller, Michael; Walpoth, Beat H

    2014-01-01

    There is a continuous search for shelf-ready small-caliber vascular prostheses with satisfactory early and late results. Biodegradable scaffolds, repopulated by recipient's cells regenerating a neovessel, can be a suitable option for adult and pediatric, urgent and elective cardiovascular procedures. This was a short-term experimental assessment of a new biodegradable vascular prosthesis for arterial replacement in the pig. Eleven pigs underwent bilateral carotid artery replacement with biodegradable electrospun poly-ε-caprolactone (PCL) nanofiber prostheses (internal diameter, 4 mm; length, 5 cm); or expanded polytetrafluoroethylene (ePTFE) prostheses as control. Perioperative anticoagulation was achieved with intravenous heparin (double baseline activated clotting time). Postoperatively, until conclusion of the study at 1 month, animals received aspirin and clopidogrel daily. Transit time flow was measured intraoperatively and at sacrifice. Doppler ultrasound (1 and 4 weeks) and a selective carotid angiography (4 weeks) were performed to assess patency. All explanted grafts were analyzed by histology, morphometry, and scanning electron microscopy in order to study graft-host interaction. Surgical handling and hemostasis of the new prostheses were excellent. Patency rate was 78% (7/9) for PCL grafts, compared with 67% (4/6) for ePTFE grafts. Transit time flow and Doppler ultrasound showed no significant changes in flow and velocity or diameter over time in both groups. Both prostheses showed no detectable in vivo compliance as compared with native carotid artery. Percent neoendothelialization was 86% for PCL and 58% for ePTFE grafts (P = .008). Neointima formation was equal in both grafts. More adventitial infiltration of macrophages, myofibroblasts, and capillaries was seen in PCL grafts with a milder foreign-body reaction when compared with ePTFE implants. Both grafts showed similar endoluminal thrombus formation. Biodegradable, electrospun PCL grafts showed

  16. An alternative graft fixation technique for scaphoid nonunions treated with vascular bone grafting.

    Science.gov (United States)

    Korompilias, Anastasios V; Lykissas, Marios G; Kostas-Agnantis, Ioannis P; Gkiatas, Ioannis; Beris, Alexandros E

    2014-07-01

    To present our experience with vascularized bone grafting based on the 1,2-intercompartmental supraretinacular artery for the management of established scaphoid nonunion and to investigate the efficacy of graft immobilization with a combination of Kirschner wires and transarticular external fixation. A retrospective chart and radiographic review was conducted for patients with the diagnosis of scaphoid nonunion of the proximal pole or the waist treated with the 1,2-intercompartmental supraretinacular artery-based vascularized graft and fixed with a combination of Kirschner wires and transarticular external fixation between 2007 and 2011. We observed 23 consecutive patients for a mean of 34 ± 4 months. All patients were males with mean age of 25 ± 5 years. All patients had scaphoid nonunion and associated humpback deformity. The mean duration of nonunion was 7 ± 1 months. All scaphoid nonunions united after the index procedure at a mean of 10 ± 1 weeks. Two patients had avascular necrosis of the proximal pole based on the preoperative magnetic resonance imaging findings. After surgery, deformity correction was achieved in all patients, as recorded by the decrease in the lateral intrascaphoid angle and the increase in the dorsal scaphoid angle. At the last follow-up, no patients reported wrist pain. The mean Disabilities of the Arm, Shoulder, and Hand score improved significantly from 32 ± 12 before the operation to 5 ± 3 at the last postoperative visit. All patients showed statistically significant improvement in the range of motion and the grip strength of the involved wrist. The results of this study support the combined use of Kirschner wires and transarticular external fixation for fixation of a 1,2-intercompartmental supraretinacular artery-based vascular bone graft in the treatment of scaphoid nonunions. Therapeutic IV. Copyright © 2014 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  17. Revascularization of femoral head ischemic necrosis with vascularized bone graft: A CT scan experimental study

    International Nuclear Information System (INIS)

    Gonzalez del Pino, J.; Knapp, K.; Gomez Castresana, F.; Benito, M.

    1990-01-01

    An ischemic necrosis of the femoral head was induced in 15 mongrel adult dogs using the technique described by Gartsman et al. Five weeks later, a free vascularized rib graft was transferred into the previously induced ischemic femoral head. High resolution computed tomographic scanning was used to evaluate revascularization 4, 8 and 12 weeks after grafting. The femoral head exhibited new vessel formation throughout the study. Arterial terminal branches arising from the rib graft medullary and periosteal circulations extended beyond the rib graft, entered the head, and reached the subchondral plate. Even where the rib graft did not replenish the central core of the head, there was vascular supply from the grafted bone's vascular tree. These results suggest that a free vascularized bone graft is able to revascularize an experimentally induced ischemic femoral head necrosis. (orig.)

  18. Bio-absorbable antibiotic impregnated beads for the treatment of prosthetic vascular graft infections.

    Science.gov (United States)

    Genovese, Elizabeth A; Avgerinos, Efthymios D; Baril, Donald T; Makaroun, Michel S; Chaer, Rabih A

    2016-12-01

    There is limited investigation into the use of bio-absorbable antibiotic beads for the treatment of prosthetic vascular graft infections. Our goal was to investigate the rates of infection eradication, graft preservation, and limb salvage in patients who are not candidates for graft explant or extensive reconstruction. A retrospective review of patients implanted with antibiotic impregnated bio-absorbable calcium sulfate beads at a major university center was conducted. Six patients with prosthetic graft infections were treated with bio-absorbable antibiotics beads from 2012-2014. Grafts included an aortobifemoral, an aorto-hepatic/superior mesenteric artery, and four extra-anatomic bypasses. Pathogens included Gram-positive and Gram-negative bacteria. Half of the patients underwent graft explant with reconstruction and half debridement of the original graft, all with antibiotic bead placement around the graft. Mean follow-up was 7.3 ± 8.3 months; all patients had infection resolution, healed wounds, and 100% graft patency, limb salvage, and survival. This report details the successful use of bio-absorbable antibiotic beads for the treatment prosthetic vascular graft infections in patients at high risk for graft explant or major vascular reconstruction. At early follow-up, we demonstrate successful infection suppression, graft preservation, and limb salvage with the use of these beads in a subset of vascular patients. © The Author(s) 2016.

  19. Bio-absorbable antibiotic impregnated beads for the treatment of prosthetic vascular graft infections

    Science.gov (United States)

    Genovese, Elizabeth A; Avgerinos, Efthymios D; Baril, Donald T; Makaroun, Michel S; Chaer, Rabih A

    2017-01-01

    Objective There is limited investigation into the use of bio-absorbable antibiotic beads for the treatment of prosthetic vascular graft infections. Our goal was to investigate the rates of infection eradication, graft preservation, and limb salvage in patients who are not candidates for graft explant or extensive reconstruction. Methods A retrospective review of patients implanted with antibiotic impregnated bio-absorbable calcium sulfate beads at a major university center was conducted. Results Six patients with prosthetic graft infections were treated with bio-absorbable antibiotics beads from 2012–2014. Grafts included an aortobifemoral, an aorto-hepatic/superior mesenteric artery, and four extra-anatomic bypasses. Pathogens included Gram-positive and Gram-negative bacteria. Half of the patients underwent graft explant with reconstruction and half debridement of the original graft, all with antibiotic bead placement around the graft. Mean follow-up was 7.3±8.3 months; all patients had infection resolution, healed wounds, and 100% graft patency, limb salvage, and survival. Conclusion This report details the successful use of bio-absorbable antibiotic beads for the treatment prosthetic vascular graft infections in patients at high risk for graft explant or major vascular reconstruction. At early follow-up, we demonstrate successful infection suppression, graft preservation, and limb salvage with the use of these beads in a subset of vascular patients. PMID:26896286

  20. Daptomycin treatment in Gram-positive vascular graft infections

    Directory of Open Access Journals (Sweden)

    Francisco Arnaiz de las Revillas

    2018-03-01

    Full Text Available Background: Daptomycin is a bactericidal antibiotic approved for the treatment of skin and soft tissue infections and right-side endocarditis. However, there is a lack of published data outlining its usefulness in vascular graft infections (VGI. The aim of this study was to describe the clinical experience of daptomycin use in the treatment of VGI caused by Gram-positive bacteria. Methods: This was a retrospective cohort study of patients diagnosed with VGI receiving daptomycin at a tertiary care hospital during the period January 2010 to December 2012. Results: Of a total 1066 consecutive patients who had undergone vascular grafts (VG, 25 were diagnosed with VGI. Fifteen of these patients (11 prosthetic VG, three autologous VG, one both types received daptomycin (median dose 6.7 mg/kg/day, range 4.1–7.1 mg/kg/day; median age 69 years, range 45–83 years; 80% male. The infected bypass was removed in 13 cases. The most common reason for selecting daptomycin was kidney failure (53%. The Gram-positive organisms isolated were coagulase-negative Staphylococcus (n = 10, Staphylococcus aureus (n = 3 (two methicillin-resistant S. aureus, Enterococcus faecium (n = 2, and Enterococcus faecalis (n = 1. The mean follow-up was 69 months (interquartile range 48–72 months. Ten patients (66.7% achieved complete healing of the VGI. A recurrence of the infection was observed in 100% of patients in whom the bypass was not removed. Among patients who did not achieve complete healing, one needed a supracondylar amputation and one died as a consequence of infection. Five patients received treatment with rifampicin in addition to daptomycin and they were all cured. Conclusions: The use of daptomycin and surgery for Gram-positive VGI was effective and well tolerated, and this may be a good alternative for the treatment of VGI in patients with peripheral arterial disease in whom renal insufficiency is common. Keywords: Daptomycin, Gram-positive, Vascular

  1. 99mTc-leukocyte scintigraphy in prosthetic vascular graft infections

    International Nuclear Information System (INIS)

    Vorne, M.; Laitinen, J.; Lehtonen, J.; Toivio, I.; Mokka, R.; Soini, I.

    1989-01-01

    The aim of this study was to determine the diagnostic value of scintigraphy with 99m Tc-HMPAO-labelled leukocytes for the detection of prosthetic vascular graft infection. 51 scans were recorded in 19 patients with suspected vascular graft infection and 8 control patients. Three-phase scanning was used at 0.5, 3-6 and 18-24 h. 13 vascular graft infections (10 early, 3 late) were found. 12 of these healed with antibiotics and only one patient with late infection had to be reoperated. None of them died during the follow-up period. The sensitivity was 100% and the specificity 96%. 99m Tc-leukocyte scintigraphy seems a useful tool to detect vascular graft infection and to differentiate it from infections elsewhere. The results suggest that the incidence of vascular graft infection may be greater, and the mortality rate lower, than supposed before. (orig.) [de

  2. [E-PTFE Membrane for the Management of Perforated Corneal Ulcer].

    Science.gov (United States)

    Pahor, D; Pahor, A

    2016-10-01

    Purpose: To present the surgical management of perforated corneal ulcer using PRECLUDE® Pericardial Membrane, composed of expanded polytetrafluoroethylene (e-PTFE; GORE-TEX®), as an alternative surgical procedure in patients at high risk of graft rejections and to evaluate side effects for a prolonged period. Patients and Methods: The study included all patients who were admitted to our department and underwent surgical repair of perforated corneal ulcer with the e-PTFE membrane between 2010 and 2015. In total, 8 patients (8 eyes) were enrolled. Medical records of all patients were retrospectively reviewed. The operation was performed under peribulbar anaesthesia. Non-absorbable, microporous, watertight 0.1 mm thick e-PTFE membrane was used to close the corneal ulcer. The membrane was cut to overlap the defect adequately and to achieve the desired tissue attachment without preparing the conjunctiva or superficial trephination of the cornea. The membrane was fixed to the healthy cornea with several non-absorbable sutures (Prolene® 10.0), in order to achieve the proper stress without wrinkling. Results: Five of 8 patients were treated for systemic immunological diseases. Sjögren's syndrome was diagnosed in 2 patients, granulomatosis with polyangiitis in one, vasculitis with a history of previous sclerokeratitis in one and systemic lupus erythematosus in one. In 2 patients, corneal perforation was observed as a complication of corneal infection and in one patient as a late complication of a severe chemical burn. Corneal perforations were successfully covered with e-PTFE membrane in all patients. E-PTFE membrane was well tolerated in all patients and the eye was always preserved. After 3 to 4 months, the membrane was removed in 7 patients. The underlying cornea was thin, firm, stable and vascularised. In one patient with Sjögren's syndrome, the e-PTFE membrane is still in place. Conclusion: Surgical management of perforated corneal ulcer using E-PTFE membrane

  3. 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

  4. 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

  5. Decellularized ovine arteries as small-diameter vascular grafts

    International Nuclear Information System (INIS)

    Mancuso, L; Cao, G; Gualerzi, A; Boschetti, F; Loy, F

    2014-01-01

    Atherosclerosis and its complications still represent the leading cause of death in the developed countries. While autologous blood vessels may be regarded as the best solution for peripheral and coronary bypass, they are unavailable in most patients. Even though tissue engineering techniques are often applied to the development of small-diameter vascular grafts, limiting factors of this approach are represented by the lack of essential extracellular matrix proteins and/or poor biomechanical properties of the scaffolds used. Along these lines, the aim of this study was to develop a decellularization protocol for ovine carotids to be used as suitable small-diameter vascular grafts. Samples were treated either with sodium dodecyl sulphate (SDS) or with Trypsin and Triton X-100; a final nuclease digestion was performed for both protocols. Morphological analyses demonstrate complete removal of nuclei and cellular components in treated vessels, also confirmed by significant reduction in wall thickness and DNA content. Essential extracellular matrix proteins such as collagen, elastin, and fibronectin are well preserved after decellularization. From a mechanical point of view, Trypsin and Triton X-100 treated arteries show elastic modules and compliance comparable to native carotids, whereas the use of SDS makes samples stiffer, with a significant decrease in the compliance mean value and an increase in longitudinal and circumferential Young’s modules. It is demonstrated that the treatment where Trypsin and Triton X-100 are combined guarantees complete decellularization of carotids, with no significant alteration of biomechanical and structural properties, thus preserving a suitable environment for adhesion, proliferation, and migration of cells. (paper)

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

    Science.gov (United States)

    2004-12-01

    the absence of dilatation, aneurysm formation or neointimal hyperplasia . The 2003 report described the failure to provide appropriate carotid grafts...growth of fibrovascular tissue, sometimes accompanied by inflammatory cells and pigment-laden macrophages. Fragmentation of the umbilical vein...were also present within the device interstices. A fibrovascular stroma (all animals, mild to marked) was also noted within the lumen of the ePTFE

  7. Triple-Layer Vascular Grafts Fabricated by Combined E-Jet 3D Printing and Electrospinning.

    Science.gov (United States)

    Huang, Ruiying; Gao, Xiangkai; Wang, Jian; Chen, Haoxiang; Tong, Chunyi; Tan, Yongjun; Tan, Zhikai

    2018-05-29

    Small-diameter tissue-engineered vascular grafts are urgently needed for clinic arterial substitute. To simulate the structures and functions of natural blood vessels, we designed a novel triple-layer poly(ε-caprolactone) (PCL) fibrous vascular graft by combining E-jet 3D printing and electrospinning techniques. The resultant vascular graft consisted of an interior layer comprising 3D-printed highly aligned strong fibers, a middle layer made by electrospun densely fibers, and an exterior structure composed of mixed fibers fabricated by co-electrospraying. The biocompatible triple-layer graft was used for in vivo implantation, and results demonstrated that the longitudinally-aligned fibers within the lumen of the graft could enhance the proliferation and migration of endothelial cells, while maintained good mechanical properties. The exterior layer provided a pathway that encouraged cells to migrate into the scaffold after implantation. This experimental graft overcame the limitations of conventionally electrospun vascular grafts of inadequate porosity and lowly cell penetration. The unique structure of the triple-layer vascular graft promoted cell growth and infiltration in vivo, thus provided an encouraging substitute for in situ tissue engineering.

  8. 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.

  9. 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.

  10. F-18-Fluorodeoxyglucose Positron Emission Tomography/CT Scanning in Diagnosing Vascular Prosthetic Graft Infection

    NARCIS (Netherlands)

    Saleem, Ben R.; Pol, Robert A.; Slart, Riemer H. J. A.; Reijnen, Michel M. P. J.; Zeebregts, Clark J.

    2014-01-01

    Vascular prosthetic graft infection (VPGI) is a severe complication after vascular surgery. CT-scan is considered the diagnostic tool of choice in advanced VPGI. The incidence of a false-negative result using CT is relatively high, especially in the presence of low-grade infections.

  11. 111In leukocyte scintigraphy in the diagnosis of vascular graft infection

    International Nuclear Information System (INIS)

    Royen, E.A. van; Roevekamp, M.H.; Dongen, R.J.A.M. van; Schoot, J.B. van der; Hardeman, M.R.

    1982-01-01

    Infection at the site of a vascular graft is a serious complication in vascular surgery especially when synthetic materials have been used. Prosthetic grafts are widely employed in aorto-iliac, aorto-femoral and femoro-popliteal bypasses. X-ray investigation, angiography, ultrasound and computer tomography are of limited value in the diagnosis of graft infection. Delay in diagnosis and treatment of this complication results in a high morbidity and mortality. Some reports are available on the use of gallium-67 citrate scintigraphy. However, its accumulation in normal intestinal structures is a serious drawback. The authors investigated the effectiveness of indium-111 leukocytes scintigraphy in the diagnosis of vascular graft infection. The possible accumulation of labelled leukocytes was assessed both subjectively by visual interpretation and quantitatively by computer evaluation. (Auth.)

  12. 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

  13. 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

  14. Rectus femoris muscle flap based on proximal insertion mobilization to cover a groin infected vascular graft.

    Science.gov (United States)

    Silvestre, Luís; Pedro, Luís Mendes; Fernandes e Fernandes, Ruy; Silva, Emanuel; Fernandes e Fernandes, José

    2015-10-01

    The rectus femoris (RF) muscle flap, which is widely used to cover groin infected vascular grafts, is usually harvested through distal tendon division and an extensive muscle elevation and transposition into the groin wound defect. A case of a vascular prosthetic graft infection in the groin was successfully controlled after coverage with an RF flap that was harvested based on proximal portion mobilization instead of the conventional distal one. This case suggests that the RF muscle flap based on proximal insertion mobilization is a feasible, effective, technically simpler, and less invasive alternative to cover infected vascular grafts in the groin. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  15. Detection of acute synthetic vascular graft infection with IN-111 labeled leukocyte imaging

    International Nuclear Information System (INIS)

    Alazraki, N.; Dries, D.; Lawrence, P.; Murphy, K.; Kercher, J.; Datz, F.; Christian, P.; Taylor, A.

    1985-01-01

    Synthetic vascular graft infection is characterized by late diagnosis due to indolent and nonspecific symptoms. Reported data on accuracy of In-111 labeled leukocyte imaging to identify vascular graft infection is sparse and conflicting. The purpose of this animal study was to clarify the accuracy of detection of early graft infection using a mixed population of In-111 labeled leukocytes. Twelve mongrel dogs received dacron aortic interposition grafts. Seven grafts were contaminated at surgery by topical ATCC S. aureus, 10/sup 8/ organisms per ml. Six control animals received no graft contamination Mixed population In-111 homologous leukocyte labeling was performed followed by imaging at 24 and 48 hours following intravenous injection of 250 μCi In-111 leukocytes. Scans were done on Day 2 post-surgery. Infected dogs were sacrificed following Indium imaging; control dogs were rescanned at 3 weeks postop and sacrificed thereafter. Autopsy results were correlated with scans, yielding sensitivity 71%, specificity 100%, accuracy 85% for In-111 leukocyte imaging to detect early graft infection. False positive leukocyte imaging in the early postop period was not a problem. At autopsy all 5 dogs with infected grafts and positive scans had gross pus. The 2 dogs with false negative scans showed no gross pus at autopsy; cultures were positive for S. aureus in all 7 dogs. Scans at 2 days and 3 weeks post-surgery were true negatives in all 6 control dogs. These data suggest a high level of clinical reliability of leukocyte imaging for early graft infection detection

  16. 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

  17. 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 ...

  18. Electrospinning thermoplastic polyurethane/graphene oxide scaffolds for small diameter vascular graft applications

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Xin [National Engineering Research Center of Novel Equipment for Polymer Processing, The Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology, Guangzhou (China); Department of Mechanical Engineering, University of Wisconsin–Madison, WI (United States); Wisconsin Institute for Discovery, University of Wisconsin–Madison, WI (United States); Mi, Hao-Yang [National Engineering Research Center of Novel Equipment for Polymer Processing, The Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology, Guangzhou (China); Salick, Max R. [Wisconsin Institute for Discovery, University of Wisconsin–Madison, WI (United States); Department of Engineering Physics, University of Wisconsin–Madison, WI (United States); Cordie, Travis M. [Wisconsin Institute for Discovery, University of Wisconsin–Madison, WI (United States); Department of Biomedical Engineering, University of Wisconsin–Madison, WI (United States); Peng, Xiang-Fang, E-mail: pmxfpeng@scut.edu.cn [National Engineering Research Center of Novel Equipment for Polymer Processing, The Key Laboratory of Polymer Processing Engineering of Ministry of Education, South China University of Technology, Guangzhou (China); Turng, Lih-Sheng, E-mail: turng@engr.wisc.edu [Department of Mechanical Engineering, University of Wisconsin–Madison, WI (United States); Wisconsin Institute for Discovery, University of Wisconsin–Madison, WI (United States)

    2015-04-01

    Fabrication of small diameter vascular grafts plays an important role in vascular tissue engineering. In this study, thermoplastic polyurethane (TPU)/graphene oxide (GO) scaffolds were fabricated via electrospinning at different GO contents as potential candidates for small diameter vascular grafts. In terms of mechanical and surface properties, the tensile strength, Young's modulus, and hydrophilicity of the scaffolds increased with an increase of GO content while plasma treatment dramatically improved the scaffold hydrophilicity. Mouse fibroblast (3T3) and human umbilical vein endothelial cells (HUVECs) were cultured on the scaffolds separately to study their biocompatibility and potential to be used as vascular grafts. It was found that cell viability for both types of cells, fibroblast proliferation, and HUVEC attachment were the highest at a 0.5 wt.% GO loading whereas oxygen plasma treatment also enhanced HUVEC viability and attachment significantly. In addition, the suture retention strength and burst pressure of tubular TPU/GO scaffolds containing 0.5 wt.% GO were found to meet the requirements of human blood vessels, and endothelial cells were able to attach to the inner surface of the tubular scaffolds. Platelet adhesion tests using mice blood indicated that vascular scaffolds containing 0.5% GO had low platelet adhesion and activation. Therefore, the electrospun TPU/GO tubular scaffolds have the potential to be used in vascular tissue engineering. - Highlights: • TPU/GO vascular scaffolds were prepared via electrospinning. • The addition of GO improved the modulus and hydrophilicity of the scaffolds. • Fibroblast cell culture verified the scaffolds' biocompatibility. • Endothelial cell culture verified the scaffolds' vascular graft affinity. • The mechanical properties fulfilled the requirements of vascular grafts.

  19. 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

  20. Current Strategies for the Manufacture of Small Size Tissue Engineering Vascular Grafts

    Directory of Open Access Journals (Sweden)

    Michele Carrabba

    2018-04-01

    Full Text Available Occlusive arterial disease, including coronary heart disease (CHD and peripheral arterial disease (PAD, is the main cause of death, with an annual mortality incidence predicted to rise to 23.3 million worldwide by 2030. Current revascularization techniques consist of angioplasty, placement of a stent, or surgical bypass grafting. Autologous vessels, such as the saphenous vein and internal thoracic artery, represent the gold standard grafts for small-diameter vessels. However, they require invasive harvesting and are often unavailable. Synthetic vascular grafts represent an alternative to autologous vessels. These grafts have shown satisfactory long-term results for replacement of large- and medium-diameter arteries, such as the carotid or common femoral artery, but have poor patency rates when applied to small-diameter vessels, such as coronary arteries and arteries below the knee. Considering the limitations of current vascular bypass conduits, a tissue-engineered vascular graft (TEVG with the ability to grow, remodel, and repair in vivo presents a potential solution for the future of vascular surgery. Here, we review the different methods that research groups have been investigating to create TEVGs in the last decades. We focus on the techniques employed in the manufacturing process of the grafts and categorize the approaches as scaffold-based (synthetic, natural, or hybrid or self-assembled (cell-sheet, microtissue aggregation and bioprinting. Moreover, we highlight the attempts made so far to translate this new strategy from the bench to the bedside.

  1. 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.)

  2. 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.)

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

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  4. Effect of flow on vascular endothelial cells grown in tissue culture on polytetrafluoroethylene grafts

    International Nuclear Information System (INIS)

    Sentissi, J.M.; Ramberg, K.; O'Donnell, T.F. Jr.; Connolly, R.J.; Callow, A.D.

    1986-01-01

    Vascular grafts lined with endothelial cells (EC) grown to confluence in culture before implantation may provide a thromboresistant flow surface. Growth of EC on and their adherence to currently available prosthetic materials under conditions of flow are two impediments remaining in the development of such a graft. To address these problems, 22 polytetrafluoroethylene grafts (PTFE) (5 cm by 4 mm inside diameter) were pretreated with collagen and fibronectin, seeded with 2 to 3 X 10(6) bovine aortic EC per graft, and placed in tissue culture (seeded grafts). Twenty-two grafts pretreated with collagen and fibronectin alone served as controls. After 2 weeks morphologic studies revealed that 20/22 seeded grafts were lined with a confluent endothelial layer. Indium 111-oxine was then used to label the EC-seeded grafts. After exposure to either low (25 ml/min) or high (200 ml/min) flow rates for 60 minutes in an in vitro circuit, examination of the luminal surface of the graft by light microscopy and scanning electron microscopy revealed minimal loss of EC. These findings were corroborated by radionuclide scans that showed an insignificant loss of the EC-associated indium label during exposure to flow (7% low flow, 11% high flow). Pretreatment of PTFE grafts with collagen and fibronectin thus promotes both attachment and adherence of EC even under flow conditions

  5. 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

  6. 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.

  7. Total and regional blood flows in vascularized skeletal muscle grafts in rabbits

    International Nuclear Information System (INIS)

    Burton, H.W.; Stevenson, T.R.; Dysko, R.C.; Gallagher, K.P.; Faulkner, J.A.

    1988-01-01

    The transplantation of whole skeletal muscles is a common clinical procedure. Although atypical blood flows have been reported in small free muscle grafts, the blood flow of large neurovascular-intact (NVI) and neurovascular-anastomosed (NVA) grafts have not been measured. Because the maximum specific force (N/cm 2 ) of NVI and NVA grafts is 65% that of control muscles, we hypothesized that total and regional blood flows of NVI and NVA grafts at rest and during twitch contractions are significantly lower than lower flows of control muscles. In rabbits, blood flows of control rectus femoris (RFM) muscles and NVI and NVA grafts of RFM muscles were measured by the radioactive-microsphere technique. Total blood flows in grafts were not different from the control RFM muscle values, except for a higher resting flow in NVA grafts and a lower flow at 3 Hz in NVI grafts. Minor variations in regional flows were observed. We conclude that the operative procedures of grating and repair of blood vessels affect the vascular bed of muscles minimally, and the deficits observed in grafts do not arise from inadequate perfusion

  8. 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

  9. The mechanical properties of infrainguinal vascular bypass grafts: their role in influencing patency.

    Science.gov (United States)

    Sarkar, S; Salacinski, H J; Hamilton, G; Seifalian, A M

    2006-06-01

    When autologous vein is unavailable, prosthetic graft materials, particularly expanded polytetrafluoroethylene are used for peripheral arterial revascularisation. Poor long term patency of prosthetic materials is due to distal anastomotic intimal hyperplasia. Intimal hyperplasia is directly linked to shear stress abnormalities at the vessel wall. Compliance and calibre mismatch between native vessel and graft, as well as anastomotic line stress concentration contribute towards unnatural wall shear stress. High porosity reduces graft compliance by causing fibrovascular infiltration, whereas low porosity discourages the development of an endothelial lining and hence effective antithrombogenicity. Therefore, consideration of mechanical properties is necessary in graft development. Current research into synthetic vascular grafts concentrates on simulating the mechanical properties of native arteries and tissue engineering aims to construct a new biological arterial conduit.

  10. 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.

  11. Development of a gelatin-based polyurethane vascular graft by spray, phase-inversion technology

    International Nuclear Information System (INIS)

    Losi, Paola; Al Kayal, Tamer; Briganti, Enrica; Volpi, Silvia; Soldani, Giorgio; Mancuso, Luisa; Cao, Giacomo; Celi, Simona; Gualerzi, Alice

    2015-01-01

    The capacity of a composite vascular graft constituting polyurethane (PU) and gelatin to support cell growth was investigated using human mesenchymal stem cells (hMSCs). Gelatin-based polyurethane grafts were fabricated by co-spraying polyurethane and gelatin using a spray, phase-inversion technique. Graft microstructure was investigated by light and scanning electron microscopy. Uniaxial tensile tests were performed to assess the grafts’ mechanical properties in longitudinal and circumferential directions. hMSCs obtained from bone marrow aspirate were seeded onto flat graft samples. After 24, 48, and 72 h of incubation, cell morphology was evaluated by Giemsa staining and cell viability was calculated by XTT assay. SEM analysis evidenced that PU samples display a microporous structure, whereas the gelatin-based PU samples show a fibrillar appearance. The presence of cross-linked gelatin produced a significant increase of ultimate tensile strength and ultimate elongation in circumferential directions compared to PU material. Qualitative analysis of hMSC adhesion onto the grafts revealed remarkable differences between gelatin-based PU and control graft. hMSCs grown onto gelatin-based PU graft form a monolayer that reached confluence at 72 h, whereas cells seeded onto the control graft were not able to undergo appropriate spreading. hMSCs grown onto gelatin-based PU graft showed significantly higher viability than cells seeded onto bare PU at all time points. In conclusion, a composite vascular graft was successfully manufactured by simultaneous co-spraying of a synthetic polymer and a protein to obtain a scaffold that combines the mechanical characteristics of polyurethanes with the favorable cell interaction features of gelatin. (paper)

  12. Prosthetic vascular graft infection through a median sternotomy: a multicentre review †.

    Science.gov (United States)

    Oda, Tatsuya; Minatoya, Kenji; Kobayashi, Junjiro; Okita, Yutaka; Akashi, Hidetoshi; Tanaka, Hiroyuki; Kawaharada, Nobuyoshi; Saiki, Yoshikatsu; Kuniyoshi, Yukio; Nishimura, Kunihiro

    2015-06-01

    The aim of this study is to analyse the treatment outcomes of thoracic prosthetic graft infection. A retrospective chart review was conducted at six hospitals and included the records of 68 patients treated for postoperative prosthetic vascular graft infection (mean age: 62.3 ± 15.1, male 51) from January 2000 to December 2013. The number of patients and the locations of the treated infections were as follows: 13 for aortic root, 16 for ascending aorta, 35 for aortic arch and 4 for aortic root to arch. In-hospital infection occurred in 43 patients and after discharge in 25. The mean follow-up time was 2.0 ± 2.3 years. The follow-up rate was 94.1%. The most commonly isolated micro-organism was Staphylococcus aureus (72.1%). Rereplacement of infectious graft was performed in 18 patients (Dacron graft in 12, homograft in 4 and rifampicin-bonded Dacron graft in 2). The overall hospital mortality rate was 35.3% (24/68). The mortality rate among the patients with graft rereplacement was 33.3% (6/18), with pedicled muscle flaps or pedicled omental flaps to cover the graft 25.9% (7/27), with irrigation 55.0% (11/20) and on antibiotic therapy only 0% (0/3). Our multivariate analysis demonstrated that the risk factors of hospital death increased in the absence of pedicled flaps (muscle or omentum) to cover the graft (P = 0.001), age over 55 (P = 0.003), time from onset of initial operation prosthetic vascular graft infection have not been satisfactory. However, the use of pedicled muscle or omental flaps to cover the graft could improve the outcomes. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  13. Surgical and Antimicrobial Treatment of Prosthetic Vascular Graft Infections at Different Surgical Sites: A Retrospective Study of Treatment Outcomes

    Science.gov (United States)

    Elzi, Luigia; Gurke, Lorenz; Battegay, Manuel; Widmer, Andreas F.; Weisser, Maja

    2014-01-01

    Objective Little is known about optimal management of prosthetic vascular graft infections, which are a rare but serious complication associated with graft implants. The goal of this study was to compare and characterize these infections with respect to the location of the graft and to identify factors associated with outcome. Methods This was a retrospective study over more than a decade at a tertiary care university hospital that has an established multidisciplinary approach to treating graft infections. Cases of possible prosthetic vascular graft infection were identified from the hospital's infectious diseases database and evaluated against strict diagnostic criteria. Patients were divided into groups according to the locations of their grafts: thoracic-aortic, abdominal-aortic, or peripheral-arterial. Statistical analyses included evaluation of patient and infection characteristics, time to treatment failure, and factors associated specifically with cure rates in aortic graft infections. The primary endpoint was cure at one year after diagnosis of the infection. Results Characterization of graft infections according to the graft location did show that these infections differ in terms of their characteristics and that the prognosis for treatment seems to be influenced by the location of the infection. Cure rate and all-cause mortality at one year were 87.5% and 12.5% in 24 patients with thoracic-aortic graft infections, 37.0% and 55.6% in 27 patients with abdominal-aortic graft infections, and 70.0% and 30.0% in 10 patients with peripheral-arterial graft infections. In uni- and multivariate analysis, the type of surgical intervention used in managing infections (graft retention versus graft replacement) did not affect primary outcome, whereas a rifampicin-based antimicrobial regimen was associated with a higher cure rate. Conclusions We recommend that future prospective studies differentiate prosthetic vascular graft infections according to the location of the

  14. 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.

  15. Indium-111 labeled purified granulocytes in the diagnosis of synthetic vascular graft infection

    International Nuclear Information System (INIS)

    Forstrom, L.A.; Dewanjee, M.K.; Chowdhury, S.; Brown, M.L.

    1988-01-01

    Indium-111 labeled leukocytes have been shown to be useful in the diagnosis of synthetic vascular graft infection. To minimize the potential effects of labeled red blood cells and platelets on image interpretation, the authors prepared purified autologous granulocytes (PG) from 84 ml of blood using Volex enhanced gravity sedimentation and Ficoll-Hypaque double density centrifugation. The labeling efficiency of PG with In-111 tropolone was 90 +/- 9% (mean +/- SD). Imaging was performed 18-24 hours following injection of approximately 445 microcuries of In-111 PG in 26 patients with suspected infection of vascular grafts that had been implanted 12 days to 12 years prior to the study. In ten patients with proven graft infection, seven had positive In-111 PG scans. Ten of 11 patients without infection had negative scans. In five patients with clinically equivocal findings, scan results were positive in one, negative in one, and equivocal in three. A false-positive scan occurred in a patient with an uninfected inflammatory pseudoaneurysm of an aortic graft. These results confirm an earlier report that In-111 PG imaging is a useful technique in the diagnosis of synthetic vascular graft infection

  16. Conservative treatment of vascular prosthetic graft infection is associated with high mortality

    NARCIS (Netherlands)

    Saleem, Ben R.; Meetwaldt, Robbert; Tielliu, Ignace F. J.; Verhoeven, Eric L. G.; van den Dungen, Jan J. A. M.; Zeebregts, Clark J.

    BACKGROUND: The aim of this study was to identify patient-related and/or disease-related factors that influence outcomes in patients with vascular prosthetic graft infections. METHODS: Through the hospital patient administration system, between January 1997 and December 2007, a total of 44 patients

  17. 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.

  18. Anti-inflammatory and Antibacterial Effects of Covalently Attached Biomembrane-Mimic Polymer Grafts on Gore-Tex Implants.

    Science.gov (United States)

    Jin, Young Ju; Kang, Sunah; Park, Pona; Choi, Dongkil; Kim, Dae Woo; Jung, Dongwook; Koh, Jaemoon; Jeon, Joohee; Lee, Myoungjin; Ham, Jiyeon; Seo, Ji-Hun; Jin, Hong-Ryul; Lee, Yan

    2017-06-07

    Expanded polytetrafluoroethylene (ePTFE), also known as Gore-Tex, is widely used as an implantable biomaterial in biomedical applications because of its favorable mechanical properties and biochemical inertness. However, infection and inflammation are two major complications with ePTFE implantations, because pathogenic bacteria can inhabit the microsized pores, without clearance by host immune cells, and the limited biocompatibility can induce foreign body reactions. To minimize these complications, we covalently grafted a biomembrane-mimic polymer, poly(2-methacryloyloxylethyl phosphorylcholine) (PMPC), by partial defluorination followed by UV-induced polymerization with cross-linkers on the ePTFE surface. PMPC grafting greatly reduced serum protein adsorption as well as fibroblast adhesion on the ePTFE surface. Moreover, the PMPC-grafted ePTFE surface exhibited a dramatic inhibition of the adhesion and growth of Staphylococcus aureus, a typical pathogenic bacterium in ePTFE implants, in the porous network. On the basis of an analysis of immune cells and inflammation-related factors, i.e., transforming growth factor-β (TGF-β) and myeloperoxidase (MPO), we confirmed that inflammation was efficiently alleviated in tissues around PMPC-grafted ePTFE plates implanted in the backs of rats. Covalent PMPC may be an effective strategy for promoting anti-inflammatory and antibacterial functions in ePTFE implants and to reduce side effects in biomedical applications of ePTFE.

  19. In vitro model for human endothelial cell seeding of a small diameter vascular graft

    International Nuclear Information System (INIS)

    Kent, K.C.; Oshima, A.; Ikemoto, T.; Whittemore, A.D.

    1988-01-01

    A precise system was devised to measure the kinetics of attachment of human venous endothelium to a variety of materials and substrates. Cells were labelled in a postconfluent state with tritiated thymidine, harvested, and a cell suspension seeded into a 4 mm PTFE graft. After a 90 minute incubation period, one half of the graft segment was sacrificed and the remaining portion placed in a perfusion system (225 cc/min) for 1 hour. Graft segments, effluents, and seeding suspension were assayed in a beta scintillation counter. The percentage of cells that attached pre- and postperfusion were determined, as well as the retrieval of tritium from the system. Initially, 71% of seeded cells attached to grafts coated with fibronectin, with significantly less (60%) remaining attached after perfusion. Only 10% of cells initially attached to uncoated grafts, with 4% retained postperfusion. Retrieval of tritium averaged 102 +/- 10% for all experiments. This system determines both pre- and postperfusion attachment of human endothelial cells to vascular grafts following manipulation of numerous variables, including graft material, substrate, incubation time, and seeding density. An optimal seeding protocol for human trials can thus be determined

  20. Endothelial chimerism and vascular sequestration protect pancreatic islet grafts from antibody-mediated rejection

    Science.gov (United States)

    Chen, Chien-Chia; Pouliquen, Eric; Broisat, Alexis; Andreata, Francesco; Racapé, Maud; Bruneval, Patrick; Kessler, Laurence; Ahmadi, Mitra; Bacot, Sandrine; Saison-Delaplace, Carole; Marcaud, Marina; Van Huyen, Jean-Paul Duong; Loupy, Alexandre; Villard, Jean; Demuylder-Mischler, Sandrine; Morelon, Emmanuel; Tsai, Meng-Kun; Kolopp-Sarda, Marie-Nathalie; Koenig, Alice; Mathias, Virginie; Ghezzi, Catherine; Dubois, Valerie; Defrance, Thierry

    2017-01-01

    Humoral rejection is the most common cause of solid organ transplant failure. Here, we evaluated a cohort of 49 patients who were successfully grafted with allogenic islets and determined that the appearance of donor-specific anti-HLA antibodies (DSAs) did not accelerate the rate of islet graft attrition, suggesting resistance to humoral rejection. Murine DSAs bound to allogeneic targets expressed by islet cells and induced their destruction in vitro; however, passive transfer of the same DSAs did not affect islet graft survival in murine models. Live imaging revealed that DSAs were sequestrated in the circulation of the recipients and failed to reach the endocrine cells of grafted islets. We used murine heart transplantation models to confirm that endothelial cells were the only accessible targets for DSAs, which induced the development of typical microvascular lesions in allogeneic transplants. In contrast, the vasculature of DSA-exposed allogeneic islet grafts was devoid of lesions because sprouting of recipient capillaries reestablished blood flow in grafted islets. Thus, we conclude that endothelial chimerism combined with vascular sequestration of DSAs protects islet grafts from humoral rejection. The reduced immunoglobulin concentrations in the interstitial tissue, confirmed in patients, may have important implications for biotherapies such as vaccines and monoclonal antibodies. PMID:29202467

  1. 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.

  2. Islet graft survival and function: concomitant culture and transplantation with vascular endothelial cells in diabetic rats.

    Science.gov (United States)

    Pan, Xiaoming; Xue, Wujun; Li, Yang; Feng, Xinshun; Tian, Xiaohui; Ding, Chenguang

    2011-12-15

    Human islet transplantation is a great potential therapy for type I diabetes. To investigate islet graft survival and function, we recently showed the improved effects after co-culture and co-transplantation with vascular endothelial cells (ECs) in diabetic rats. ECs were isolated, and the viability of isolated islets was assessed in two groups (standard culture group and co-culture group with ECs). Then streptozotocin-induced diabetic rats were divided into four groups before islet transplantation as follows: group A with infusion of islet grafts; group B with combined vascular ECs and islet grafts; groups C and D as controls with single ECs infusion and phosphate-buffered saline injection, respectively. Blood glucose and insulin concentrations were measured daily. Expression of vascular endothelial growth factor was investigated by immunohistochemical staining. The mean microvascular density was also calculated. More than 90% of acridine orange-propidium iodide staining positive islets demonstrated normal morphology while co-cultured with ECs for 7 days. Compared with standard control, insulin release assays showed a significantly higher simulation index in co-culture group except for the first day (Ptransplantation, there was a significant difference in concentrations of blood glucose and insulin among these groups after 3 days (Pislet group (P=0.04). Co-culture with ECs in vitro could improve the survival and function of isolated rat islet, and co-transplantation of islets with ECs could effectively prolong the islet graft survival in diabetic rats.

  3. Application of a vascular graft material (Solcograft-P) in experimental surgery.

    Science.gov (United States)

    Nemes, A; Acsády, G; Fraefel, W; Lichti, H; Monos, E; Oertli, R; Somogyi, E; Sótonyi, P

    1985-09-01

    The implantation and post-implantation behaviour of a Solcograft-P vascular prosthesis in the aortic, aorto-iliac, carotid and vena caval positions in dogs was studied up to 100 d post-surgery in order to assess the suitability of this vascular material for use in man. Solcograft-P is prepared from the carotid arteries of calves by crosslinking the collagen stroma using adipyl dichloride. During the postoperative follow-up period of 3 month, 100% of the aortal grafts, 80% of the aorto-iliac bypasses, 60% of the vena caval grafts and 35% of the carotid implants remained patent. The biochemical properties of the Solcograft-P are better than those of Solcograft, its predecessor. The intimal lining was consistently smooth and homogeneous in grafts of biological origin, and no aneurysm was observed. Infection and early thrombosis occured no more frequently than with other grafts. The new Solcograft-P, crosslinked via ester and amide groups, seems to represent a real improvement over Solcograft. Our results suggest that Solcograft-P should prove valuable in various cases of reconstructive vascular surgery of the lower limb, especially when the autologous vena saphena magna is not available, and its mechanical properties may well prove suitable for both arterial and venous replacement.

  4. 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.

  5. Multidisciplinary Treatment Approach for Prosthetic Vascular Graft Infection in the Thoracic Aortic Area

    Science.gov (United States)

    Watanabe, Yoshinori

    2015-01-01

    Prosthetic vascular graft infection in the thoracic aortic area is a rare but serious complication. Adequate management of the complication is essential to increase the chance of success of open surgery. While surgical site infection is suggested as the root cause of the complication, it is also related to decreased host tolerance, especially as found in elderly patients. The handling of prosthetic vascular graft infection has been widely discussed to date. This paper mainly provides a summary of literature reports published within the past 5 years to discuss issues related to multidisciplinary treatment approaches, including surgical site infection, timing of onset, diagnostic methods, causative pathogens, auxiliary diagnostic methods, antibiotic treatment, anti-infective structures of vascular prostheses, surgical treatment, treatment strategy against infectious aortic aneurysms, future surgical treatment, postoperative systemic therapy, and antimicrobial stewardship. A thorough understanding of these issues will enable us to prevent prosthetic vascular graft infection in the thoracic aortic area as far as possible. In the event of its occurrence, the early introduction of appropriate treatment is expected to cure the disease without worsening of the underlying pathological condition. PMID:26356686

  6. Development of an electrospun biomimetic polyurea scaffold suitable for vascular grafting.

    Science.gov (United States)

    Madhavan, Krishna; Frid, Maria G; Hunter, Kendall; Shandas, Robin; Stenmark, Kurt R; Park, Daewon

    2018-01-01

    The optimization of biomechanical and biochemical properties of a vascular graft to render properties relevant to physiological environments is a major challenge today. These critical properties of a vascular graft not only regulate its stability and integrity, but also control invasion of cells for scaffold remodeling permitting its integration with native tissue. In this work, we have synthesized a biomimetic scaffold by electrospinning a blend of a polyurea, poly(serinol hexamethylene urea) (PSHU), and, a polyester, poly-ε-caprolactone (PCL). Mechanical properties of the scaffold were varied by varying polymer blending ratio and electrospinning flow rate. Mechanical characterization revealed that scaffolds with lower PSHU content relative to PCL content resulted in elasticity close to native mammalian arteries. We also found that increasing electrospinning flow rates also increased the elasticity of the matrix. Optimization of elasticity generated scaffolds that enabled vascular smooth muscle cells (SMCs) to adhere, grow and maintain a SMC phenotype. The 30/70 scaffold also underwent slower degradation than scaffolds with higher PSHU content, thereby, providing the best option for in vivo remodeling. Further, Gly-Arg-Gly-Asp-Ser (RGD) covalently conjugated to the polyurea backbone in 30/70 scaffold resulted in significantly increased clotting times. Reducing surface thrombogenicity by the conjugation of RGD is critical to avoiding intimal hyperplasia. Hence, biomechanical and biochemical properties of a vascular graft can be balanced by optimizing synthesis parameters and constituent components. For these reasons, the optimized RGD-conjugated 30/70 scaffold electrospun at 2.5 or 5 mL/h has great potential as a suitable material for vascular grafting applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 278-290, 2018. © 2017 Wiley Periodicals, Inc.

  7. 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

  8. Treating fat grafts with human endothelial progenitor cells promotes their vascularization and improves their survival in diabetes mellitus.

    Science.gov (United States)

    Hamed, Saher; Ben-Nun, Ohad; Egozi, Dana; Keren, Aviad; Malyarova, Nastya; Kruchevsky, Danny; Gilhar, Amos; Ullmann, Yehuda

    2012-10-01

    Bone marrow-derived endothelial progenitor cells are required for vascularization of a fat graft to form a functional microvasculature within the graft and to facilitate its integration into the surrounding tissues. Organ transplantation carries a high risk of graft loss and rejection in patients with diabetes mellitus because endothelial progenitor cell function is impaired. The authors investigated the influence of endothelial progenitor cell treatment on the phenotype and survival of human fat grafts in immunocompromised mice with experimentally induced diabetes mellitus. The authors injected 1 ml of human fat tissue into the scalps of 14 nondiabetic and 28 diabetic immunocompromised mice, and then treated some of the grafts with endothelial progenitor cells that was isolated from the blood of a human donor. The phenotype of the endothelial progenitor cell-treated fat grafts from the 14 diabetic mice was compared with that of the untreated fat grafts from 14 nondiabetic and 14 diabetic mice, 18 days and 15 weeks after fat transplantation. Determination of graft phenotype included measurements of weight and volume, vascular endothelial growth factor levels, vascular endothelial growth factor receptor-2, endothelial nitric oxide synthase, and caspase 3 expression levels, and histologic analysis of the extent of vascularization. The untreated grafts from the diabetic mice were fully resorbed 15 weeks after fat transplantation. The phenotype of endothelial progenitor cell-treated fat grafts from the diabetic mice was similar to that of the untreated fat grafts from the nondiabetic mice. Endothelial progenitor cell treatment of transplanted fat can increase the survival of a fat graft by inducing its vascularization and decreasing the extent of apoptosis.

  9. 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

  10. 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.

  11. Coating of Dacron vascular grafts with an ionic polyurethane: a novel sealant with protein binding properties.

    Science.gov (United States)

    Phaneuf, M D; Dempsey, D J; Bide, M J; Quist, W C; LoGerfo, F W

    2001-03-01

    The purpose of this study was to develop a novel sealant that would seal prosthetic vascular graft interstices and be accessible for protein binding. Crimped knitted Dacron vascular grafts were cleaned (CNTRL) and hydrolyzed in boiling sodium hydroxide (HYD). These HYD grafts were sealed using an 11% solids solution of a polyether-based urethane with carboxylic acid groups (PEU-D) via a novel technique that employs both trans-wall and luminal perfusion. Carboxylic acid content, determined via methylene blue dye uptake, was 2.3- and 4.2-fold greater in PEU-D segments (1.0+/-0.27 nmol/mg) as compared to HYD and CNTRL segments, respectively. Water permeation through PEU-D graft (1.1+/-2 ml/cm2 min(-1)) was comparable to collagen-impregnated Dacron (9.8+/-10 ml/cm2 min(-1)). Non-specific 125I-albumin (125I-Alb) binding to PEU-D segments (18+/-3 ng/mg) was significantly lower than HYD and CNTRL segments. 125I-Alb linkage to PEU-D using the crosslinker EDC resulted in 5.7-fold greater binding (103+/-2 ng/mg) than non-specific PEU-D controls. However, covalent linkage of 125I-Alb to PEU-D was 4.9- and 5.9-fold less than CNTRL and HYD segments with EDC, respectively. Thus, ionic polyurethane can be applied to a pre-formed vascular graft, seal the interstices and create "anchor" sites for protein attachment.

  12. Biomechanical comparison of expanded polytetrafluoroethylene (ePTFE) and PTFE interpositional patches and direct tendon-to-bone repair for massive rotator cuff tears in an ovine model.

    Science.gov (United States)

    McKeown, Andrew Dj; Beattie, Rebekah F; Murrell, George Ac; Lam, Patrick H

    2016-01-01

    Massive irreparable rotator cuff tears are a difficult problem. Modalities such as irrigation and debridement, partial repair, tendon transfer and grafts have been utilized with high failure rates and mixed results. Synthetic interpositional patch repairs are a novel and increasingly used approach. The present study aimed to examine the biomechanical properties of common synthetic materials for interpositional repairs in contrast to native tendon. Six ovine tendons, six polytetrafluoroethylene (PTFE) felt sections and six expanded PTFE (ePTFE) patch sections were pulled-to-failure to analyze their biomechanical and material properties. Six direct tendon-to-bone surgical method repairs, six interpositional PTFE felt patch repairs and six interpositional ePTFE patch repairs were also constructed in ovine shoulders and pulled-to-failure to examine the biomechanical properties of each repair construct. Ovine tendon had higher load-to-failure (591 N) and had greater stiffness (108 N/mm) than either PTFE felt (296 N, 28 N/mm) or ePTFE patch sections (323 N, 34 N/mm). Both PTFE felt and ePTFE repair techniques required greater load-to-failure (225 N and 177 N, respectively) than direct tendon-to-bone surgical repairs (147 N) in ovine models. Synthetic materials lacked several biomechanical properties, including strength and stiffness, compared to ovine tendon. Interpositional surgical repair models with these materials were significantly stronger than direct tendon-to-bone model repairs.

  13. 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.

  14. [Free tissue transfers with lengthening of vascular pedicle using interpositional vein grafts. About 10 cases].

    Science.gov (United States)

    Yeo, S; Perrot, P; Duteille, F

    2010-04-01

    The realization of free flaps with lack of reliable vessels nearby the loss of substance is a difficult problem for plastic surgeons. We report 10 cases of free tissue transfers with a one-stage technique lengthening the vascular pedicle of the free flap with interpositional vein grafts. Taking into consideration the good results and the low rate of morbidity, the authors emphasize the use of this technique rather than a two-stage procedure. Copyright 2009 Elsevier Masson SAS. All rights reserved.

  15. Arterial grafts exhibiting unprecedented cellular infiltration and remodeling in vivo: the role of cells in the vascular wall.

    Science.gov (United States)

    Row, Sindhu; Peng, Haofan; Schlaich, Evan M; Koenigsknecht, Carmon; Andreadis, Stelios T; Swartz, Daniel D

    2015-05-01

    To engineer and implant vascular grafts in the arterial circulation of a pre-clinical animal model and assess the role of donor medial cells in graft remodeling and function. Vascular grafts were engineered using Small Intestinal Submucosa (SIS)-fibrin hybrid scaffold and implanted interpositionally into the arterial circulation of an ovine model. We sought to demonstrate implantability of SIS-Fibrin based grafts; examine the remodeling; and determine whether the presence of vascular cells in the medial wall was necessary for cellular infiltration from the host and successful remodeling of the implants. We observed no occlusions or anastomotic complications in 18 animals that received these grafts. Notably, the grafts exhibited unprecedented levels of host cell infiltration that was not limited to the anastomotic sites but occurred through the lumen as well as the extramural side, leading to uniform cell distribution. Incoming cells remodeled the extracellular matrix and matured into functional smooth muscle cells as evidenced by expression of myogenic markers and development of vascular reactivity. Interestingly, tracking the donor cells revealed that their presence was beneficial but not necessary for successful grafting. Indeed, the proliferation rate and number of donor cells decreased over time as the vascular wall was dominated by host cells leading to significant remodeling and development of contractile function. These results demonstrate that SIS-Fibrin grafts can be successfully implanted into the arterial circulation of a clinically relevant animal model, improve our understanding of vascular graft remodeling and raise the possibility of engineering mural cell-free arterial grafts. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. 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.

  17. 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.

  18. Prosthetic vascular graft infection and prosthetic joint infection caused by Pseudomonas 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.

  19. 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...

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

    Science.gov (United States)

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

    2015-11-01

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

  1. 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.

  2. In vivo canine studies of a Sinkhole valve and vascular graft coated with biocompatible PU-PEO-SO3.

    Science.gov (United States)

    Han, D K; Lee, K B; Park, K D; Kim, C S; Jeong, S Y; Kim, Y H; Kim, H M; Min, B G

    1993-01-01

    PU-PEO-SO3 was applied as a coating material over a newly designed Sinkhole bileaflet PU heart valve and a porous PU vascular graft. Performance and biocompatibility were evaluated using an in vivo canine shunt system between the right ventricle and pulmonary artery. The survival periods in three implantations were 14, 24, and 39 days, during which no mechanical failure occurred in any Sinkhole valve or vascular graft. Scanning electron microscopy (SEM) studies demonstrated much less platelet adhesion and thrombus formation on PU-PEO-SO3 grafts than on PU vascular grafts. Cracks in the valve leaflet were occasionally observed on PU surfaces, but not on PU-PEO-SO3. After a 39 day implantation, calcium deposition on vascular grafts was decreased as compared with valve leaflets, and calcification on PU-PEO-SO3 was much lower than on PU. These results suggest that Sinkhole valves and vascular grafts are promising, and PU-PEO-SO3 as a coating material is more blood compatible, biostable, and calcification resistant in vivo than in untreated PU.

  3. 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.

  4. Vascular graft infection: Detection by 123I-labeled antigranulocyte antibody (anti-NCA95) scintigraphy

    International Nuclear Information System (INIS)

    Cordes, M.; Hepp, W.; Langer, R.; Pannhorst, J.; Hierholzer, J.; Felix, R.; Universitaetsklinikum Rudolf Virchow, Berlin

    1991-01-01

    A total of 40 scintigraphic examinations were performed after vascular reconstructive surgery in 27 patients in whom there was a clinical suspicion of vascular graft infection. Whole-body gamma camera images were obtained at 4 and 24 h after i.v. administration of 111 MBq 123 I-labeled antigranulocyte antibody Anti-NCA95. Scan results were interpreted without clincal information and were subsequently correlated with computed tomography. Prosthetic vascular graft infection was confirmed in 9 patients and excluded in 18 by surgical findings, bacteriology and/or clinical course. Scintigraphy revealed true-positive results in 16 of 40 and false-negative results in 1 of 40 examinations. True-negative results were found in 19 and 16, false-positive results in 4 and 7 examinations at 4 and 24 h p.i., resp. The sensitivity was calculated to be 94% for both early (4 h) and late (24 h) images whereas the specificity ws 83% and 70%, resp. In all cases the application of the murine antibody was safe and no side effects or complications were noted. Limitations of this diagnostic procedure are accumulations of granulocytes in hematomas which may be observed in the non-complicated early course following reconstructive surgery. (orig.) [de

  5. Quantitative evaluation of endothelial cell attachment to vascular graft materials using In-111 Oxine label

    Energy Technology Data Exchange (ETDEWEB)

    Park, H.M.; Kesler, K.A.; Stinson, J.; Mock, B.; Arnold, M.

    1985-05-01

    Human umbilical vein endothelial cells were harvested, cultured and labeled with In-111 oxine using a modification of the technique described by Sharefkin et al. Average cell labeling efficiency was 42%. Two graft materials, polytetrafluoroethylene (Gortex) and polyester elastomer (Hytrel), with and without pretreatment with human fibronectin (FN) were incubated with the labeled cells. Quantitation of In-111 activity was done 3 times: at inoculation, after incubation (attachment) and after 1 hr of in vitro perfusion (retention). The average attachment ranged from 53% to 99.5%. The In-111 activity attached ranged from 10 to 20 ..mu..Ci per graft. A gamma camera with medium energy collimator and two pulse height analyzers for 173 and 247 keV photons with 20% window and an on-line computer was used. Images were obtained in 1.5 zoom mode. The count rate response to a In-111 point source up to 150 ..mu..Ci was linear. The results indicate Hytrel permits better endothelial cell attachment than Gortex and FN coating enhances the strength of attachment to both graft materials. The authors conclude that In-111 Oxine labeling is a reliable method for quantitatively evaluating endothelial cell attachment to vascular graft materials.

  6. "In Situ Vascular Nerve Graft" for Restoration of Intrinsic Hand Function: An Anatomical Study.

    Science.gov (United States)

    Mozaffarian, Kamran; Zemoodeh, Hamid Reza; Zarenezhad, Mohammad; Owji, Mohammad

    2018-06-01

    In combined high median and ulnar nerve injury, transfer of the posterior interosseous nerve branches to the motor branch of the ulnar nerve (MUN) is previously described in order to restore intrinsic hand function. In this operation a segment of sural nerve graft is required to close the gap between the donor and recipient nerves. However the thenar muscles are not innervated by this nerve transfer. The aim of the present study was to evaluate whether the superficial radial nerve (SRN) can be used as an "in situ vascular nerve graft" to connect the donor nerves to the MUN and the motor branch of median nerve (MMN) at the same time in order to address all denervated intrinsic and thenar muscles. Twenty fresh male cadavers were dissected in order to evaluate the feasibility of this modification of technique. The size of nerve branches, the number of axons and the tension at repair site were evaluated. This nerve transfer was technically feasible in all specimens. There was no significant size mismatch between the donor and recipient nerves Conclusions: The possible advantages of this modification include innervation of both median and ulnar nerve innervated intrinsic muscles, preservation of vascularity of the nerve graft which might accelerate the nerve regeneration, avoidance of leg incision and therefore the possibility of performing surgery under regional instead of general anesthesia. Briefly, this novel technique is a viable option which can be used instead of conventional nerve graft in some brachial plexus or combined high median and ulnar nerve injuries when restoration of intrinsic hand function by transfer of posterior interosseous nerve branches is attempted.

  7. 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.

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

    Science.gov (United States)

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

    2016-11-01

    The aim of this study was to evaluate histologically the following treatment of bilateral localized gingival recessions with coronally advanced flap (CAF) combined with platelet-rich fibrin (PRF) or subepithelial connective tissue graft (SCTG). Tissue samples were harvested from 14 subjects either 1 or 6 months after the surgeries. The 2-mm punch biopsies were obtained from the mid-portion of the grafted sites. Neutral buffered formalin fixed, paraffin-embedded 5-μm thick tissue sections were stained with hematoxylin eosin and Masson's trichrome in order to analyze the collagen framework, epithelium thickness and rete-peg length. Multiple sequential sections were cut from paraffin-embedded blocks of tissue and immunohistochemically prepared for detection of vascular endothelial growth factor, CD31 and CD34, for the assessment of vascularization. Rete peg formation was significantly increased in the sites treated with PRF compared to the SCTG group after 6 months (p < 0.05). On the contrary, the number of vessels was increased in the SCTG group compared to the PRF group after 6 months (p < 0.05). No statistically significant differences were observed in the collagen density. Staining intensity of CD31 increased in submucosal area of PRF group than SCTG group after 1 month. Higher staining intensity of CD34 was observed in the submucosal area of PRF group compared with SCTG group after 6 months. The results of the present study suggest that in histological evaluation because of its biological compounds, PRF results earlier vessel formation and tissue maturation compared to connective tissue graft. PRF regulated the vascular response associated with an earlier wound healing.

  9. 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.

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    Aortic vascular prosthetic graft infection (AVPGI) with Staphylococcus aureus is a feared post-operative complication. This study was conducted to evaluate the clinical signs and potential biomarkers of infection in a porcine AVPGI model. The biomarkers evaluated were: C-reactive protein (CRP......), fibrinogen, white blood cells (WBC), major histocompatibility complex II (MHC II) density, lymphocyte CD4:CD8 ratio and tumour necrosis factor-alpha (TNF-α) in vitro responsiveness. Sixteen pigs were included in the study, and randomly assigned into four groups (n = 4): “SHAM” pigs had their infra...

  11. Enterocutaneous fistula associated with ePTFE mesh: case report and review of the literature.

    Science.gov (United States)

    Foda, M; Carlson, M A

    2009-06-01

    A case of enterocutaneous fistula secondary to the erosion of an expanded polytetrafluoroethylene (ePTFE) prosthesis into the jejunum is described. This case is unusual secondary to the long experience with ePTFE and the lack of published cases similar to this one. The technical details of this case reveal extenuating circumstances associated with the fistula formation, and it is concluded that this particular case does not provide sufficient evidence to implicate ePTFE, by itself, as an etiologic agent for gastrointestinal fistulization. In addition, the published safety record of ePTFE in abdominal wall surgery is reviewed.

  12. 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%

  13. 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.

  14. A comparison of patency and interventions in thigh versus Hemodialysis Reliable Outflow grafts for chronic hemodialysis vascular access.

    Science.gov (United States)

    Brownie, Evan R; Kensinger, Clark D; Feurer, Irene D; Moore, Derek E; Shaffer, David

    2016-11-01

    With improvements in medical management and survival of patients with end-stage renal disease, maintaining durable vascular access is increasingly challenging. This study compared primary, assisted primary, and secondary patency, and procedure-specific complications, and evaluated whether the number of interventions to maintain or restore patency differed between prosthetic femoral-femoral looped inguinal access (thigh) grafts and Hemodialysis Reliable Outflow (HeRO; Hemosphere Inc, Minneapolis, Minn) grafts. A single-center, retrospective, intention-to-treat analysis was conducted of consecutive thigh and HeRO grafts placed between May 2004 and June 2015. Medical history, interventions to maintain or restore patency, and complications were abstracted from the electronic medical record. Data were analyzed using parametric and nonparametric statistical tests, Kaplan-Meier survival methods, and multivariable proportional hazards regression and logistic regression. Seventy-six (43 thigh, 33 HeRO) grafts were placed in 61 patients (54% male; age 53 [standard deviation, 13] years). Median follow-up time in the intention-to-treat analysis was 21.2 months (min, 0.0; max, 85.3 months) for thigh grafts and 6.7 months (min, 0.0; max, 56.3 months) for HeRO grafts (P = .02). The groups were comparable for sex, age, coronary artery disease, diabetes mellitus, peripheral vascular disease, and smoking history (all P ≥ .12). One thigh graft (2%) and five HeRO (15%) grafts failed primarily. In the intention-to-treat analysis, patency durations were significantly longer in the thigh grafts (all log-rank P ≤ .01). Point estimates of primary patency at 6 months, 1 year, and 3 years were 61%, 46%, and 4% for the thigh grafts and 25%, 15%, and 6% for the HeRO grafts. Point estimates of assisted primary patency at 6 months, 1 year, and 3 years were 75%, 66%, and 54% for the thigh grafts and 41%, 30%, and 10% for the HeRO grafts. Point estimates of secondary patency at 6

  15. 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

  16. 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.

  17. 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.

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

    International Nuclear Information System (INIS)

    Mercado-Pagán, Ángel E.; Kang, Yunqing; Findlay, Michael W.; Yang, Yunzhi

    2015-01-01

    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 −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

  19. Stem Cells on Biomaterials for Synthetic Grafts to Promote Vascular Healing

    Science.gov (United States)

    Babczyk, Patrick; Conzendorf, Clelia; Klose, Jens; Schulze, Margit; Harre, Kathrin; Tobiasch, Edda

    2014-01-01

    This review is divided into two interconnected parts, namely a biological and a chemical one. The focus of the first part is on the biological background for constructing tissue-engineered vascular grafts to promote vascular healing. Various cell types, such as embryonic, mesenchymal and induced pluripotent stem cells, progenitor cells and endothelial- and smooth muscle cells will be discussed with respect to their specific markers. The in vitro and in vivo models and their potential to treat vascular diseases are also introduced. The chemical part focuses on strategies using either artificial or natural polymers for scaffold fabrication, including decellularized cardiovascular tissue. An overview will be given on scaffold fabrication including conventional methods and nanotechnologies. Special attention is given to 3D network formation via different chemical and physical cross-linking methods. In particular, electron beam treatment is introduced as a method to combine 3D network formation and surface modification. The review includes recently published scientific data and patents which have been registered within the last decade. PMID:26237251

  20. 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

  1. Simulation of blood flow in a small-diameter vascular graft model with a swirl (spiral) flow guider.

    Science.gov (United States)

    Zhang, ZhiGuo; Fan, YuBo; Deng, XiaoYan; Wang, GuiXue; Zhang, He; Guidoin, Robert

    2008-10-01

    Small-diameter vascular grafts are in large demand for coronary and peripheral bypass procedures, but present products still fail in long-term clinical application. In the present communication, a new type of small-diameter graft with a swirl flow guider was proposed to improve graft patency rate. Flow pattern in the graft was simulated numerically and compared with that in a conventional graft. The numerical results revealed that the swirl flow guider could indeed make the blood flow rotate in the new graft. The swirling flow distal to the flow guider significantly altered the flow pattern in the new graft and the velocity profiles were re-distributed. Due to the swirling flow, the blood velocity near the vessel wall and wall shear rate were greatly enhanced. We believe that the increased blood velocity near the wall and the wall shear rate can impede the occurrence of acute thrombus formation and intimal hyperplasia, hence can improve the graft patency rate for long-term clinical use.

  2. 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.

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    We evaluated the results of limb-sparing surgery and reconstruction of bone defects with vascularized fibula grafts in 8 consecutive patients (mean age at operation 13.6 years (range 4.1-24.2 years), female/male = 6/2) with bone sarcomas (BS) (osteosarcoma/Ewing's sarcoma/chondrosarcoma= 4....../3/1) operated on form 2000 to 2006. The bone defects reconstructed were proximal femoral diaphysis and epiphysis (n = 2), humeral diaphysis (n = 2), humeral proximal diaphysis and epiphysis (n = 1), femoral diaphysis (n = 1), ulnar diaphysis (n = 1), and tibial diaphysis (n = 1). One patient with Ewing......'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...

  4. Accuracy of FDG-PET-CT in the Diagnostic Work-up of Vascular Prosthetic Graft Infection

    NARCIS (Netherlands)

    Bruggink, J. L. M.; Glaudemans, A. W. J. M.; Saleem, B. R.; Meerwaldt, R.; Alkefaji, H.; Prins, T. R.; Start, R. H. J. A.; Zeebregts, C. J.

    Objectives: To investigate the diagnostic accuracy of fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) compared with computed tomography (CT) scanning and added value of fused FDG-PET CT in diagnosing vascular prosthetic graft infection. Design: Prospective cohort study with

  5. Small diameter electrospun silk fibroin vascular grafts: Mechanical properties, in vitro biodegradability, and in vivo biocompatibility.

    Science.gov (United States)

    Catto, Valentina; Farè, Silvia; Cattaneo, Irene; Figliuzzi, Marina; Alessandrino, Antonio; Freddi, Giuliano; Remuzzi, Andrea; Tanzi, Maria Cristina

    2015-09-01

    To overcome the drawbacks of autologous grafts currently used in clinical practice, vascular tissue engineering represents an alternative approach for the replacement of small diameter blood vessels. In the present work, the production and characterization of small diameter tubular matrices (inner diameter (ID)=4.5 and 1.5 mm), obtained by electrospinning (ES) of Bombyx mori silk fibroin (SF), have been considered. ES-SF tubular scaffolds with ID=1.5 mm are original, and can be used as vascular grafts in pediatrics or in hand microsurgery. Axial and circumferential tensile tests on ES-SF tubes showed appropriate properties for the specific application. The burst pressure and the compliance of ES-SF tubes were estimated using the Laplace's law. Specifically, the estimated burst pressure was higher than the physiological pressures and the estimated compliance was similar or higher than that of native rat aorta and Goretex® prosthesis. Enzymatic in vitro degradation tests demonstrated a decrease of order and crystallinity of the SF outer surface as a consequence of the enzyme activity. The in vitro cytocompatibility of the ES-SF tubes was confirmed by the adhesion and growth of primary porcine smooth muscle cells. The in vivo subcutaneous implant into the rat dorsal tissue indicated that ES-SF matrices caused a mild host reaction. Thus, the results of this investigation, in which comprehensive morphological and mechanical aspects, in vitro degradation and in vitro and in vivo biocompatibility were considered, indicate the potential suitability of these ES-SF tubular matrices as scaffolds for the regeneration of small diameter blood vessels. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. 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.

  7. Utility of the indium 111-labeled human immunoglobulin G scan for the detection of focal vascular graft infection

    International Nuclear Information System (INIS)

    LaMuraglia, G.M.; Fischman, A.J.; Strauss, H.W.; Keech, F.; Wilkinson, R.; Callahan, R.J.; Khaw, B.A.; Rubin, R.H.

    1989-01-01

    The ability to diagnose and localize vascular graft infections has been a major challenge. Recent studies in animal models and humans with focal bacterial infection have shown that radiolabeled, polyclonal, human immunoglobulin G accumulates at the site of inflammation and can serve as the basis for an imaging technique. This study investigated this new technique for the diagnosis and localization of vascular graft infections. Twenty-five patients with suspected vascular infections involving grafts (22), atherosclerotic aneurysms (2), and subclavian vein thrombophlebitis (1) were studied. Gamma camera images of the suspected area were obtained between 5 and 48 hours after intravenous administration of 1.5 to 2.0 mCi (56 to 74 mBq) of indium 111-labeled, human, polyclonal immunoglobulin G. Scan results were interpreted without clinical information about the patient and were subsequently correlated with surgical findings, other imaging modalities, and/or clinical follow-up. In 10 of 10 patients found to have positive scan results, localized infections were confirmed at the involved sites. In 14 of 15 patients whose scan results were interpreted as negative, no vascular infections were identified at follow-up. The patient with false-negative results and recurrent bacteremia from an aortoduodenal fistula was found to have a negative scan outcome at a time when his disease was quiescent. These data suggest that nonspecific, human, indium 111-labeled immunoglobulin G scanning can be a useful noninvasive means of localizing vascular infections

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

    Directory of Open Access Journals (Sweden)

    Fu-Jun Wang

    2014-01-01

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

  9. In Vivo Evaluation of Short-Term Performance of New Three-Layer Collagen-Based Vascular Graft Designed for Low-Flow Peripheral Vascular Reconstructions

    Directory of Open Access Journals (Sweden)

    Tomas Grus

    2018-01-01

    Full Text Available Aim. The aim of this study was to evaluate short-term patency of the new prosthetic graft and its structural changes after explantation. Methods. The study team developed a three-layer conduit composed of a scaffold made from polyester coated with collagen from the inner and outer side with an internal diameter of 6 mm. The conduit was implanted as a bilateral bypass to the carotid artery in 7 sheep and stenosis was created in selected animals. After a period of 161 days, the explants were evaluated as gross and microscopic specimens. Results. The initial flow rate (median ± IQR in grafts with and without artificial stenosis was 120±79 ml/min and 255±255 ml/min, respectively. Graft occlusion occurred after 99 days in one of 13 conduits (patency rate: 92%. Wall-adherent thrombi occurred only in sharp curvatures in two grafts. Microscopic evaluation showed good engraftment and preserved structure in seven conduits; inflammatory changes with foci of bleeding, necrosis, and disintegration in four conduits; and narrowing of the graft due to thickening of the wall with multifocal separation of the outer layer in two conduits. Conclusions. This study demonstrates good short-term patency rates of a newly designed three-layer vascular graft even in low-flow conditions in a sheep model.

  10. 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.

  11. 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.

  12. 18F-Fluorodeoxyglucose Positron Emission Tomography/CT Scanning in Diagnosing Vascular Prosthetic Graft Infection

    Science.gov (United States)

    Saleem, Ben R.; Pol, Robert A.; Slart, Riemer H. J. A.; Reijnen, Michel M. P. J.; Zeebregts, Clark J.

    2014-01-01

    Vascular prosthetic graft infection (VPGI) is a severe complication after vascular surgery. CT-scan is considered the diagnostic tool of choice in advanced VPGI. The incidence of a false-negative result using CT is relatively high, especially in the presence of low-grade infections. 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) scanning has been suggested as an alternative for the diagnosis and assessment of infectious processes. Hybrid 18F-FDG PET/CT has established the role of 18F-FDG PET for the assessment of suspected VPGI, providing accurate anatomic localization of the site of infection. However, there are no clear guidelines for the interpretation of the uptake patterns of 18F-FDG as clinical tool for VPGI. Based on the available literature it is suggested that a linear, diffuse, and homogeneous uptake should not be regarded as an infection whereas focal or heterogeneous uptake with a projection over the vessel on CT is highly suggestive of infection. Nevertheless, 18F-FDG PET and 18F-FDG PET/CT can play an important role in the detection of VPGI and monitoring response to treatment. However an accurate uptake and pattern recognition is warranted and cut-off uptake values and patterns need to be standardized before considering the technique to be the new standard. PMID:25210712

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

    Energy Technology Data Exchange (ETDEWEB)

    Centola, M; Rainer, A; Trombetta, M [Laboratory of Chemistry and Biomaterials, CIR-Center of Integrated Research, University Campus Bio-Medico of Rome (Italy); Spadaccio, C; Genovese, J A [Area of Cardiovascular Surgery, CIR-Center of Integrated Research, University Campus Bio-Medico of Rome (Italy); De Porcellinis, S, E-mail: m.trombetta@unicampus.i [Complex Systems and Security Laboratory, CIR-Center of Integrated Research, University Campus Bio-Medico of Rome (Italy)

    2010-03-15

    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-epsilon-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.

  14. 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.

  15. 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.

  16. 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.

  17. Visualization of a prosthetic vascular graft due to platelet contamination during 111Indium-labeled leukocyte scintigraphy

    International Nuclear Information System (INIS)

    Oates, E.; Ramberg, K.

    1988-01-01

    A prosthetic axillo-femoral bypass graft was visualized during 111 In-labeled leukocyte scintigraphy in a patient referred for possible abdominal abscess. The presence of significant cardiac blood-pool activity raised the possibility that this uptake was due to deposition of contaminating labeled platelets rather than labeled leukocytes. An analysis of a small sample of the patient's blood confirmed that the circulating activity was due to labeled platelets. Increased activity along prosthetic vascular grafts in patients undergoing 111 In-labeled leukocyte scintigraphy may be due to adherent platelet, and not indicative of infection

  18. Improving the Outcome of Vein Grafts: Should Vascular Surgeons Turn Veins into Arteries?

    OpenAIRE

    Isaji, Toshihiko; Hashimoto, Takuya; Yamamoto, Kota; Santana, Jeans M.; Yatsula, Bogdan; Hu, Haidi; Bai, Hualong; Jianming, Guo; Kudze, Tambudzai; Nishibe, Toshiya; Dardik, Alan

    2017-01-01

    Autogenous vein grafts remain the gold standard conduit for arterial bypass, particularly for the treatment of critical limb ischemia. Vein graft adaptation to the arterial environment, i.e., adequate dilation and wall thickening, contributes to the superior performance of vein grafts. However, abnormal venous wall remodeling with excessive neointimal hyperplasia commonly causes vein graft failure. Since the PREVENT trials failed to improve vein graft outcomes, new strategies focus on the ada...

  19. Manufacture of small calibre quadruple lamina vascular bypass grafts using a novel automated extrusion-phase-inversion method and nanocomposite polymer.

    Science.gov (United States)

    Sarkar, Sandip; Burriesci, Gaetano; Wojcik, Adam; Aresti, Nicholas; Hamilton, George; Seifalian, Alexander M

    2009-04-16

    Long-term patency of expanded polytetrafluoroethylene (ePTFE) small calibre cardiovascular bypass prostheses (hyperplasia due to low compliance, stimulating the search for elastic alternatives. Wall porosity allows effective post-implantation graft healing, encouraging endothelialisation and a measured fibrovascular response. We have developed a novel poly (carbonate) urethane-based nanocomposite polymer incorporating polyhedral oligomeric silsesquioxane (POSS) nanocages (UCL-NANO) which shows anti-thrombogenicity and biostability. We report an extrusion-phase-inversion technique for manufacturing uniform-walled porous conduits using UCL-NANO. Image analysis-aided wall measurement showed that two uniform wall-thicknesses could be specified. Different coagulant conditions revealed the importance of low-temperature phase-inversion for graft integrity. Although minor reduction of pore-size variation resulted from the addition of ethanol or N,N-dimethylacetamide, high concentrations of ethanol as coagulant did not provide uniform porosity throughout the wall. Tensile testing showed the grafts to be elastic with strength being directly proportional to weight. The ultimate strengths achieved were above those expected from haemodynamic conditions, with anisotropy due to the manufacturing process. Elemental analysis by energy-dispersive X-ray analysis did not show a regional variation of POSS on the lumen or outer surface. In conclusion, the automated vertical extrusion-phase-inversion device can reproducibly fabricate uniform-walled small calibre conduits from UCL-NANO. These elastic microporous grafts demonstrate favourable mechanical integrity for haemodynamic exposure and are currently undergoing in-vivo evaluation of durability and healing properties.

  20. Grafting

    Energy Technology Data Exchange (ETDEWEB)

    Garnett, J L [New South Wales Univ., Kensington (Australia). School of Chemistry

    1979-01-01

    The unique value of ionizing radiation for the initiation of grafting to backbone polymers is discussed. The principles of the technique are briefly reviewed. The conditions under which free radicals and ions participate in these reactions are examined. Examples of representative grafting processes are considered to illustrate where the technique can be of potential commercial value to a wide range of industries. The general principles of these grafting reactions are shown to be applicable to radiation induced rapid cure technology such as is provided by electron beam processing facilities. Grafting reactions initiated by UV are also treated and shown to be of importance because of the many similarities in properties of the ionizing radiation and UV systems, also the rapid industrial exploitation of EB and sensitized UV processing technology. Possible future trends in radiation grafting are outlined.

  1. 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.

  2. Sustained release of vancomycin from novel biodegradable nanofiber-loaded vascular prosthetic grafts: in vitro and in vivo study

    OpenAIRE

    Liu, Kuo-Sheng; Lee, Cheng-Hung; Wang, Yi-Chuan; Liu, Shih-Jung

    2015-01-01

    Kuo-Sheng Liu,1 Cheng-Hung Lee,2 Yi-Chuan Wang,3 Shih-Jung Liu3 1Department of Thoracic and Cardiovascular Surgery, Chang Gung Memorial Hospital, Linkou, Taiwan; 2Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Linkou, Taiwan; 3Department of Mechanical Engineering, Chang Gung University, Tao-Yuan, Taiwan Abstract: This study describes novel biodegradable, drug-eluting nanofiber-loaded vascular prosthetic grafts that provide local and sustained...

  3. 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

  4. Tissue Engineering at the Blood-Contacting Surface: A Review of Challenges and Strategies in Vascular Graft Development.

    Science.gov (United States)

    Radke, Daniel; Jia, Wenkai; Sharma, Dhavan; Fena, Kemin; Wang, Guifang; Goldman, Jeremy; Zhao, Feng

    2018-05-07

    Tissue engineered vascular grafts (TEVGs) are beginning to achieve clinical success and hold promise as a source of grafting material when donor grafts are unsuitable or unavailable. Significant technological advances have generated small-diameter TEVGs that are mechanically stable and promote functional remodeling by regenerating host cells. However, developing a biocompatible blood-contacting surface remains a major challenge. The TEVG luminal surface must avoid negative inflammatory responses and thrombogenesis immediately upon implantation and promote endothelialization. The surface has therefore become a primary focus for research and development efforts. The current state of TEVGs is herein reviewed with an emphasis on the blood-contacting surface. General vascular physiology and developmental challenges and strategies are briefly described, followed by an overview of the materials currently employed in TEVGs. The use of biodegradable materials and stem cells requires careful control of graft composition, degradation behavior, and cell recruitment ability to ensure that a physiologically relevant vessel structure is ultimately achieved. The establishment of a stable monolayer of endothelial cells and the quiescence of smooth muscle cells are critical to the maintenance of patency. Several strategies to modify blood-contacting surfaces to resist thrombosis and control cellular recruitment are reviewed, including coatings of biomimetic peptides and heparin. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Treatment of osteonecrosis of the femoral head by free vascularized fibular grafting: an analysis of surgical outcome and patient health status

    Science.gov (United States)

    Louie, Brian E.; McKee, Michael D.; Richards, Robin R.; Mahoney, James L.; Waddell, James P.; Beaton, Dorcas E.; Schemitsch, Emil H.; Yoo, Daniel J.

    1999-01-01

    Objective To evaluate the limb-specific outcome and general health status of patients with osteonecrosis of the femoral head treated with vascularized fibular grafting. Design A retrospective review. Setting A single tertiary care centre. Patients Fifty-five consecutive patients with osteonecrosis of the femoral head who underwent fibular grafting (8 bilaterally). Intervention Vascularized fibular grafting. Outcome measures Limb-specific scores (Harris Hip Score, St. Michael’s Hospital Hip Score), general health status (Nottingham Health Profile, SF-36 health status survey) and radiographic outcome measures (Steinberg stage). Results Patients were young (mean age 34 years, range from 18 to 52 years) and 80% had advanced osteonecrosis (Steinberg stages IV and V). Fifty-nine hips were followed up for an average of 50 months (range from 24 to 117 months) after vascularized fibular grafting. Sixteen hips (27%) were converted to total hip arthroplasty (THA). To date, 73% of hips treated with vascularized fibular grafting have required no further surgery. Preoperative and postoperative Harris Hip Scores were 57.3 and 83.6 respectively (p < 0.001). As measured by patient-oriented health status questionnaires (SF-36, Nottingham Health Profile) and compared with population controls, patients had normal mental health scores and only slight decreases in physical component scores. Conclusions Free vascularized fibular grafting for osteonecrosis of the femoral head provides satisfactory pain relief, functional improvement and general health status and halts the progression of symptomatic disease. PMID:10459327

  6. Sustained Thromboresistant Bioactivity with Reduced Intimal Hyperplasia of Heparin-Bonded Polytetrafluoroethylene Propaten Graft in a Chronic Canine Femoral Artery Bypass Model.

    Science.gov (United States)

    Freeman, John; Chen, Aaron; Weinberg, Roy J; Okada, Tamuru; Chen, Changyi; Lin, Peter H

    2018-05-01

    Bypass graft thrombosis remains a significant mode of failure in prosthetic graft revascularization. The purpose of this investigation was to evaluate the long-term thromboresistant effect of heparin-bonded expanded polytetrafluoroethylene (ePTFE) graft using Carmeda BioActive Surface technology in a canine model. Bilateral femorofemoral artery bypass grafts with ePTFE grafts were performed in 25 adult grayhound dogs. In each animal, a heparin-bonded ePTFE graft (Propaten, WL Gore) was placed on one side, whereas a control nonheparin graft was placed on the contralateral side. The graft patency was assessed at 1, 6, 12, 18, and 24 months (n = 5 per group) following the bypass. Heparin bioactivity of the graft material was analyzed. The effect of intimal hyperplasia was also assessed. All bypass grafts were patent at 1 month. Significantly greater patency rates were noted in the Propaten group compared to the control group at 12, 18, and 24 months, which were 84%, 80%, and 80% vs. 55%, 35%, and 20%, respectively (P  0.05). Heparin-bonded ePTFE graft provides a thromboresistant surface and reduced anastomotic intimal hyperplasia at 2 years. The stable heparin bioactivity of the Propaten graft confers an advantage in long-term graft patency. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  7. 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.

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

    African Journals Online (AJOL)

    and distal 5 cm are preserved to prevent injury to the common peroneal nerve and to retain the stability of the ankle joint.[10,11] Functional outcome in those who had successful graft incorporation was generally good. It is noteworthy that none of our patient had stress fracture which is said to be common when the grafts are ...

  9. 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

  10. Anterior versus posterior approach in reconstruction of infected nonunion of the tibia using the vascularized fibular graft: potentialities and limitations.

    Science.gov (United States)

    Amr, Sherif M; El-Mofty, Aly O; Amin, Sherif N

    2002-01-01

    The potentialities, limitations, and technical pitfalls of the vascularized fibular grafting in infected nonunions of the tibia are outlined on the basis of 14 patients approached anteriorly or posteriorly. An infected nonunion of the tibia together with a large exposed area over the shin of the tibia is better approached anteriorly. The anastomosis is placed in an end-to-end or end-to-side fashion onto the anterior tibial vessels. To locate the site of the nonunion, the tibialis anterior muscle should be retracted laterally and the proximal and distal ends of the site of the nonunion debrided up to healthy bleeding bone. All the scarred skin over the anterior tibia should be excised, because it becomes devitalized as a result of the exposure. To cover the exposed area, the fibula has to be harvested with a large skin paddle, incorporating the first septocutaneous branch originating from the peroneal vessels before they gain the upper end of the flexor hallucis longus muscle. A disadvantage of harvesting the free fibula together with a skin paddle is that its pedicle is short. The skin paddle lies at the antimesenteric border of the graft, the site of incising and stripping the periosteum. In addition, it has to be sutured to the skin at the recipient site, so the soft tissues (together with the peroneal vessels), cannot be stripped off the graft to prolong its pedicle. Vein grafts should be resorted to, if the pedicle does not reach a healthy segment of the anterior tibial vessels. Defects with limited exposed areas of skin, especially in questionable patency of the vessels of the leg, require primarily a fibula with a long pedicle that could easily reach the popliteal vessels and are thus better approached posteriorly. In this approach, the site of the nonunion is exposed medial to the flexor digitorum muscle and the proximal and distal ends of the site of the nonunion debrided up to healthy bleeding bone. No attempt should be made to strip the scarred skin off

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-02-15

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

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

    International Nuclear Information System (INIS)

    Bae, Jae Ik; Won, Je Hwan; Jang, Eun Ho; Lee, Sung Yeong; Ko, Kwang Tae; Jin, Bo Hwan; Lee, June Woo

    2012-01-01

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

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

    Science.gov (United States)

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

    2018-01-01

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

  14. Proximal Pole Scaphoid Nonunion Reconstruction With 1,2 Intercompartmental Supraretinacular Artery Vascularized Graft and Compression Screw Fixation.

    Science.gov (United States)

    Morris, Mark S; Zhu, Andy F; Ozer, Kagan; Lawton, Jeffrey N

    2018-02-06

    To review the incidence of union of patients with proximal pole scaphoid fracture nonunions treated using a 1,2 intercompartmental supraretinacular artery (1,2 ICSRA) vascularized graft and a small compression screw. This is a retrospective case series of 12 patients. Calculations of the size of the proximal pole fragment relative to the total scaphoid were performed using posteroanterior view scaphoid radiographs with the wrist in ulnar deviation and flat on the cassette. Analyses were repeated 3 times per subject, and the average ratio of proximal pole fragment relative to the entire scaphoid was calculated. We reviewed medical records, radiographs, and computed tomography (CT) scans of these 12 patients. The CT scans that were performed after an average of 12 weeks were ultimately used to confirm union of the scaphoid fractures. One patient was unable to have a CT so was excluded from the final calculation. All 11 (100%) scaphoid fractures that were assessed by CT were found to be healed at the 12-week assessment point. The mean proximal pole fragment size was 18% (range, 7%-27%) of the entire scaphoid. The 1,2 ICSRA vascularized graft and compression screw was an effective treatment for patients with proximal pole scaphoid fractures. Therapeutic IV. Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  15. Engineering anatomically shaped vascularized bone grafts with hASCs and 3D-printed PCL scaffolds.

    Science.gov (United States)

    Temple, Joshua P; Hutton, Daphne L; Hung, Ben P; Huri, Pinar Yilgor; Cook, Colin A; Kondragunta, Renu; Jia, Xiaofeng; Grayson, Warren L

    2014-12-01

    The treatment of large craniomaxillofacial bone defects is clinically challenging due to the limited availability of transplantable autologous bone grafts and the complex geometry of the bones. The ability to regenerate new bone tissues that faithfully replicate the anatomy would revolutionize treatment options. Advances in the field of bone tissue engineering over the past few decades offer promising new treatment alternatives using biocompatible scaffold materials and autologous cells. This approach combined with recent advances in three-dimensional (3D) printing technologies may soon allow the generation of large, bioartificial bone grafts with custom, patient-specific architecture. In this study, we use a custom-built 3D printer to develop anatomically shaped polycaprolactone (PCL) scaffolds with varying internal porosities. These scaffolds are assessed for their ability to support induction of human adipose-derived stem cells (hASCs) to form vasculature and bone, two essential components of functional bone tissue. The development of functional tissues is assessed in vitro and in vivo. Finally, we demonstrate the ability to print large mandibular and maxillary bone scaffolds that replicate fine details extracted from patient's computed tomography scans. The findings of this study illustrate the capabilities and potential of 3D printed scaffolds to be used for engineering autologous, anatomically shaped, vascularized bone grafts. © 2014 Wiley Periodicals, Inc.

  16. 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.

  17. Dilatation of aortic grafts over time: what to expect and when to be concerned

    DEFF Research Database (Denmark)

    Schroeder, Torben V; Eldrup, Nikolaj; Just, Sven

    2009-01-01

    Dilatation of aortic prosthetic grafts is commonly reported, but most reports are anecdotal, with little objective data in the literature. We performed a prospective trial of 303 patients who underwent prosthetic graft repair for aortic aneurysm or occlusive disease, randomizing patients between...... insertion of a woven polyester or expanded polytetrafluoroethylene (ePTFE) graft. Patients were followed with computed tomography and ultrasonography for up to 5 years in order to assess the frequency and magnitude of postoperative dilatation. Graft dilatation was documented in patients with polyester...... grafts at 12 months. Thereafter and up to 60 months, polyester grafts did not dilate further. After 5 years, polyester prostheses had dilated by 25% and ePTFE by 12.5%, as determined by computed tomography imaging. These observations suggest that dilatation of prosthetic grafts is more frequent...

  18. 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

  19. 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.

  20. Does the Ventrica magnetic vascular positioner (MVP) for coronary artery bypass grafting significantly alter local fluid dynamics? A numeric study.

    Science.gov (United States)

    Morbiducci, U; Lemma, M; Ponzini, R; Boi, A; Bondavalli, L; Antona, C; Montevecchi, F M; Redaelli, A

    2007-07-01

    Automatic devices have been recently introduced to make the anastomosis procedure quick and efficient when creating a coronary bypass on the beating heart. However, the implantation of these devices could modify the graft configuration, consistently affecting the hemodynamics usually found in the traditional anastomosis. As local fluid dynamics could play a significant role in the onset of vessel wall pathologies, in this article a computational approach was designed to investigate flow patterns in the presence of the Ventrica magnetic vascular positioner (Ventrica MVP) device. A model of standard hand-sewn anastomosis and of automated magnetic anastomosis were constructed, and the finite volume method was used to simulate in silico realistic graft hemodynamics. Synthetic analytical descriptors -- i.e., time-averaged wall shear stress (TAWSS), oscillating shear index (OSI) and helical flow index (HFI) -- were calculated and compared for quantitative assessment of the anastomosis geometry hemodynamic performance. In this case study, the same most critical region was identified for the 2 models as the one with the lowest TAWSS and the highest OSI (TAWSS=0.229, OSI=0.255 for the hand-sewn anastomosis; TAWSS=0.297, OSI=0.171 for the Ventrica MVP(R)). However, the shape of the Ventrica MVP does not induce more critical wall shear stresses, oscillating flow and damped helicity in the graft fluid dynamics, as compared with conventional anastomosis. We found that the use of the Ventrica MVP for the case study under investigation was not associated with more critical fluid dynamics than with conventional hand-sewn anastomosis. Thereby, the device could facilitate beating heart and minimally invasive coronary artery bypass grafting without increasing local hemodynamic-related risks of failure.

  1. Evaluation of Blood Hemodynamics in Vascular Grafts after Total Arterial Coronary Revascularization

    Directory of Open Access Journals (Sweden)

    Ahmad Ali Amirghofran

    2016-07-01

    Full Text Available Arterial grafting has increasingly been advocated for the treatment of coronary artery disease in an attempt to improve the long-term results. In the quest to perform routine total arterial revascularization, composite Y graft methods are gaining popularity. The aim of our study was to evaluate whether blood flow in the left internal thoracic artery can provide sufficient perfusion to the entire cardiac muscle per se. Twenty patients with severe coronary artery stenosis who underwent complete arterial coronary revascularization using a composite graft entered our study. Blood flow in thoracic trunk was evaluated in three phases: cross-clamp on, cross-clamp off, and after weaning the patient from cardiopulmonary bypass. Mean arterial blood pressure in the thoracic trunk in these various positions was 62.7±3.7. left internal thora cic artery can provide sufficient blood flow to the cardiac muscles for both rest and exercise conditions.

  2. Endophytic Association of Trichoderma asperellum within Theobroma cacao Suppresses Vascular Streak Dieback Incidence and Promotes Side Graft Growth.

    Science.gov (United States)

    Rosmana, Ade; Nasaruddin, Nasaruddin; Hendarto, Hendarto; Hakkar, Andi Akbar; Agriansyah, Nursalim

    2016-09-01

    Trichoderma species are able to persist on living sapwood and leaves of cacao ( Theobroma cacao ) in an endophytic relationship. In this research, we evaluated the ability of Trichodema asperellum introduced at the incision site in the bark for side grafting with the concentration of 4 g/10 mL, 4 g/100 mL, and 4 g/1,000 mL (suspended in water) in suppressing vascular streak dieback (VSD) incidence and promoting growth of side grafts in the field. The incidence of VSD in two local clones of cacao, MCC1 and M04, without application of T. asperellum was 71.2% and 70.1% at 21 wk after grafting, respectively. However, when the two clones were treated with a concentration of 4 g/10 mL T. asperellum , the incidence was 20.6% and 21.7%, respectively, compared to 29.1% and 20.9% at 4 g/100 mL and 18.2% and 15.6% at 4 g/1,000 mL. By comparing to the control, the treatment with the same concentrations of T. asperellum listed above, the total number of stomata in MCC1 decreased by 41.9%, 30.2%, and 14.0% and in M04 by 30.5%, 21.9%, and -2.5% (exception), respectively. Otherwise, the total area of stomata opening increased by 91.4%, 99.7%, and 28.6% in MCC1 and by 203.8%, 253.5%, and 35.9% in M04, respectively. Furthermore, the number of buds and branches treated with a mixture concentration on the the two clones increased by 90.7% and 21.7%, respectively. These data showed that the application of T. asperellum to cacao scions while grafting can decrease VSD incidence in side grafts and increase growth of grafts in addition to decreasing total number of stomata, increasing total area of opened stomata, and increasing number of buds and branches.

  3. Identification of risk factors for vascular thrombosis may reduce early renal graft loss

    DEFF Research Database (Denmark)

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

    2012-01-01

    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...... were donor-age below 6 or above 60 years, or recipient-age below 5-6 years, per- or postoperative hemodynamic instability, peritoneal dialysis, diabetic nephropathy, a history of thrombosis, deceased donor, or >24 hours cold ischemia. Multiple arteries were not a risk factor, and a right kidney graft...

  4. 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.

  5. Treatment of a Common Iliac Aneurysm by Endovascular Exclusion Using the Amplatzer Vascular Plug and Femorofemoral Crossover Graft

    International Nuclear Information System (INIS)

    Coupe, Nicholas J.; Ling, Lynn; Cowling, Mark G.; Asquith, John R.; Hopkinson, Gregory B.

    2009-01-01

    We report our initial experience using the Amplatzer Vascular Plug II (AVP2) in the treatment of a left common iliac aneurysm. Following investigation by computerized tomographic angiography and catheter angiography, a 79-year-old man was found to have a markedly tortuous iliac system, with a left common iliac artery aneurysm that measured 48 mm in maximal diameter. Due to the patient's age and comorbidities the surgical opinion was that conventional open repair was not suitable. However, due to the tortuous nature of the aneurysm and iliac vessels, standard endovascular repair, using either a bifurcated or an aorto-uni-iliac stent graft, was also not possible. A combined approach was used by embolizing the ipsilateral internal iliac artery using coils and excluding the aneurysm using two AVP2 occlusion devices, followed by femorofemoral crossover grafting. Total aneurysm occlusion was achieved using this method and this allowed the patient to have a much less invasive surgical procedure than with conventional open repair of common iliac aneurysms, thus avoiding potential comorbidity and mortality.

  6. Lower limb gigantism, lymphedema, and painful varicosities following a thigh vascular access graft.

    Science.gov (United States)

    Thompson, Michael; Mathuram Thiyagarajan, Umasankar; Akoh, Jacob A

    2014-07-01

    Prosthetic arteriovenous grafts (AVGs) are associated with greater morbidity than autogenous arteriovenous fistulas (AVFs), but their use is indicated when AVF formation is not possible. This report adds to the literature a case of lower limb gigantism, painful varicosities, and lymphedema following long-term use of AVG in the upper thigh. The patient's past medical history included renal transplantation on the same side well before the AVG was inserted and right leg deep vein thrombosis. Suspicion of AVG thrombosis was excluded by Doppler ultrasound, which demonstrated an access flow of 1700 mL/min. A computed tomography (CT) scan of the abdomen and pelvis did not identify the cause of her symptoms. Whereas functional incompetence of the iliac vein valve might be responsible for the varicosities, the extent of hypertrophy in this case raises the suspicion of lymphatic blockage possibly secondary to groin dissection undertaken at the time of graft insertion, in addition to the previous dissection at the time of transplantation. This case highlights the need for minimal groin dissection during AVG insertion, particularly in patients with a history of previous abdominopelvic surgery. © 2014 International Society for Hemodialysis.

  7. Laparoscopic diaphragmatic hernia repair using expanded polytetrafluoroethylene (ePTFE) for delayed traumatic diaphragmatic hernia.

    Science.gov (United States)

    Jee, Yeseob

    2017-06-01

    Traumatic diaphragmatic hernia (TDH) is an uncommon surgical problem, and diagnosis is often delayed. However, the mortality from bowel necrosis can reach 80%. Therefore, suspicion is needed and surgery is required to prevent complications. A 50-year-old man was transferred due to abdominal pain and vomiting. Chest X-ray and computed tomography (CT) scan showed herniation of the stomach through the left diaphragm. The patient had fallen down 15 months ago and CT scan at that time revealed a small defect of the diaphragm without herniation. We diagnosed delayed herniation of TDH and the patient underwent laparoscopic repair using an expanded polytetrafluoroethylene (ePTFE) mesh. Recovery was uneventful and the CT scan at 3 months after the operation showed no recurrence. We reported a delayed presenting TDH and considered a laparoscopic approach to be safe and feasible during elective surgery. Moreover, use of an ePTFE mesh for repair of large diaphragmatic hernia was also feasible.

  8. 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

  9.  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.

  10. In vivo endothelization of tubular vascular grafts through in situ recruitment of endothelial and endothelial progenitor cells by RGD-fused mussel adhesive proteins

    International Nuclear Information System (INIS)

    Kang, Tae-Yun; Lee, Jung Ho; Kang, Jo-A; Rhie, Jong-Won; Kim, Bum Jin; Cha, Hyung Joon; Hong, Jung Min; Kim, Byoung Soo; Cho, Dong-Woo

    2015-01-01

    The use of tissue mimics in vivo, including patterned vascular networks, is expected to facilitate the regeneration of functional tissues and organs with large volumes. Maintaining patency of channels in contact with blood is an important issue in the development of a functional vascular network. Endothelium is the only known completely non-thrombogenic material; however, results from treatments to induce endothelialization are inconclusive. The present study was designed to evaluate the clinical applicability of in situ recruitment of endothelial cells/endothelial progenitor cells (EC/EPC) and pre-endothelization using a recombinant mussel adhesive protein fused with arginine–glycine–aspartic acid peptide (MAP-RGD) coating in a model of vascular graft implantation. Microporous polycaprolactone (PCL) scaffolds were fabricated with salt leaching methods and their surfaces were modified with collagen and MAP-RGD. We then evaluated their anti-thrombogenicity with an in vitro hemocompatibility assessment and a 4-week implantation in the rabbit carotid artery. We observed that MAP-RGD coating reduced the possibility of early in vivo graft failure and enhanced re-endothelization by in situ recruitment of EC/EPC (patency rate: 2/3), while endothelization prior to implantation aggravated the formation of thrombosis and/or IH (patency rate: 0/3). The results demonstrated that in situ recruitment of EC/EPC by MAP-RGD could be a promising strategy for vascular applications. In addition, it rules out several issues associated with pre-endothelization, such as cell source, purity, functional modulation and contamination. Further evaluation of long term performance and angiogenesis from the luminal surface may lead to the clinical use of MAP-RGD for tubular vascular grafts and regeneration of large-volume tissues with functional vascular networks. (paper)

  11. Tissue-engineered vascular grafts for use in the treatment of congenital heart disease: from the bench to the clinic and back again.

    Science.gov (United States)

    Patterson, Joseph T; Gilliland, Thomas; Maxfield, Mark W; Church, Spencer; Naito, Yuji; Shinoka, Toshiharu; Breuer, Christopher K

    2012-05-01

    Since the first tissue-engineered vascular graft (TEVG) was implanted in a child over a decade ago, growth in the field of vascular tissue engineering has been driven by clinical demand for improved vascular prostheses with performance and durability similar to an autologous blood vessel. Great strides were made in pediatric congenital heart surgery using the classical tissue engineering paradigm, and cell seeding of scaffolds in vitro remained the cornerstone of neotissue formation. Our second-generation bone marrow cell-seeded TEVG diverged from tissue engineering dogma with a design that induces the recipient to regenerate vascular tissue in situ. New insights suggest that neovessel development is guided by cell signals derived from both seeded cells and host inflammatory cells that infiltrate the graft. The identification of these signals and the regulatory interactions that influence cell migration, phenotype and extracellular matrix deposition during TEVG remodeling are yielding a next-generation TEVG engineered to guide neotissue regeneration without the use of seeded cells. These developments represent steady progress towards our goal of an off-the-shelf tissue-engineered vascular conduit for pediatric congenital heart surgery.

  12. En bloc prefabrication of vascularized bioartificial bone grafts in sheep and complete workflow for custom-made transplants.

    Science.gov (United States)

    Kokemüller, H; Jehn, P; Spalthoff, S; Essig, H; Tavassol, F; Schumann, P; Andreae, A; Nolte, I; Jagodzinski, M; Gellrich, N-C

    2014-02-01

    The aim of this pilot study was to determine, in a new experimental model, whether complex bioartificial monoblocs of relevant size and stability can be prefabricated in a defined three-dimensional design, in which the latissimus dorsi muscle serves as a natural bioreactor and the thoracodorsal vessel tree is prepared for axial construct perfusion. Eighteen sheep were included in the study, with six animals in each of three experimental groups. Vitalization of the β-tricalcium phosphate-based constructs was performed by direct application of unmodified osteogenic material from the iliac crest (group A), in vivo application of nucleated cell concentrate (NCC) from bone marrow aspirate (group B), and in vitro cultivation of bone marrow stromal cells (BMSC) in a perfusion bioreactor system (group C). The contours of the constructs were designed digitally and transferred onto the bioartificial bone grafts using a titanium cage, which was bent over a stereolithographic model of the defined subvolume intraoperatively. At the end of the prefabrication process, only the axial vascularized constructs of group A demonstrated vital bone formation with considerable stability. In groups B and C, the applied techniques were not able to induce ectopic bone formation. The presented computer-assisted workflow allows the prefabrication of custom-made bioartificial transplants. Copyright © 2013 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  13. A-Frame free Vascularized Fibular Graft and Femoral Lengthening for Osteosarcoma Pediatric Patients.

    Science.gov (United States)

    Cashin, Megan; Coombs, Christopher; Torode, Ian

    2018-02-01

    Pediatric limb reconstruction after resection of a malignant tumor presents specific challenges. Multiple surgical techniques have been used to treat these patients. This paper describes a staged surgical technique for the reconstruction of large distal femoral defects due to tumor resection in skeletally immature patients. Three pediatric patients with osteosarcoma of the distal femur underwent staged reconstruction. Neoadjuvant chemotherapy was followed by en bloc tumor resection and immediate reconstruction of the distal femoral defect with a vascularized free fibular autograft utilizing a unique A-frame construct combined with intramedullary nail fixation. The second stage was a planned gradual lengthening of the healed construct, over a custom-made magnetically driven expandable intramedullary nail. All patients achieved bony union and satisfactory length with minimal complications. The patients all returned to full, unlimited physical activities. The early results confirm that the described technique is a safe and reliable procedure for the reconstruction of large femoral defects in pediatric patients with osteosarcoma. Level IV-therapeutic.

  14. 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

  15. Reconstruction of juxta-articular huge defects of distal femur with vascularized fibular bone graft and Ilizarov's distraction osteogenesis.

    Science.gov (United States)

    Lai, Davy; Chen, Chuan-Mu; Chiu, Fang-Yao; Chang, Ming-Chau; Chen, Tain-Hsiung

    2007-01-01

    We evaluate the effect of reconstructing huge defects (mean, 15.8 cm) of the distal femur with Ilizarov's distraction osteogenesis and free twin-barreled vascularized fibular bone graft (TVFG). We retrospectively reviewed a consecutive series of five patients who had cases of distal femoral fractures with huge defects and infection that were treated by the Ilizarov's distraction osteogenesis. After radical debridement, two of the five cases had free TVFG and monolocal distraction osteogenesis, and another two cases had multilocal distraction osteogenesis with knee fusion because of loss of the joint congruity. The other case with floating knee injury had bilocal distraction osteogenesis and a preserved knee joint. The mean defect of distal femur was 15.8 cm (range, 14-18 cm) in length. The mean length of distraction osteogenesis by Ilizarov's apparatus was 8.2 cm. The mean length of TVFG was 8 cm. The average duration from application of Ilizarov's apparatus to achievement of bony union was 10.2 months (range, 8-13 months). At the end of the follow-up, ranges of motion of three knees were 0 to 45 degrees, 0 to 60 degrees, and 0 to 90 degrees. Two cases had knee arthrodesis with bony fusion because of loss of the joint congruity. There were no leg length discrepancies in all five patients. In addition, three patients had pin tract infections and one case had a 10 degree varus deformity of the femur. Juxta-articular huge defect (>10 cm) of distal femur remains a challenge to orthopedic surgeons. Ilizarov's technique provides the capability to maintain stability, eradicate infection, restore leg length, and to perform adjuvant reconstructive procedure easily. In this study, we found that combining Ilizarov's distraction osteogenesis with TVFG results in improved patient outcome for patients with injuries such as supracondylar or intercondylar infected fractures or nonunion of distal femur with huge bone defect.

  16. 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

  17. Biosynthetic graft failure to replace infected infrainguinal bypass as developing infection due to Morganella morganii leading to disrupture of the anastomosis. Case report

    Directory of Open Access Journals (Sweden)

    Gladiol Zenunaj

    Full Text Available Introduction: Biosynthetic prosthesis has become the trend to carry out arterial reconstruction in infected sites since considered to be resistant to infection. Late graft occlusion is the only complication reported in literature so far. We report a case of biosynthetic graft infection which led to early detachment of the femoral anastomosis of a femoral-popliteal above-knee bypass. Material: A 76-year-old man developed groin infection 3 months later after performing an ePTFE femoral-popliteal above-knee bypass for critical limb ischemia. He was re-admitted for groin infection involving the vascular structures. Explantation of the existing bypass and its replacement with a biosynthetic graft (omniflow II was performed. Detachment of the proximal anastomosis occurred 6 days later leading to groin haematoma. Consequently, retroperitoneal access was performed for clamping the external iliac artery so as to control haemorrhage followed by explantation of the biosynthetic graft. An external iliac-popliteal above-knee bypass was tailored in order to save the limb and it was performed using a transobturator approach avoiding the infected site. In both cases bacterial cultures resulted positive for Morganella Morganii. The groin wound was treated separately with negative pressure medication healing definitively within 20 days and after 3-month follow-up the bypass was still patent. Conclusion: This is the first report of biosynthetic graft infection used for infrainguinal reconstruction leading to haemorrhage due to anastomosis disrupture. Using an extra-anatomical access for providing blood inflow to the leg avoiding the infected site and treating safely the groin wound with VAC therapy revealed to be a valid approach. Keywords: Infrainguinal bypass, Graft infection, Biosynthetic material, Graft occlusion, Negative pressure medication, Morganella morgani

  18. Improved extraction of ePTFE and medical adhesive modified defibrillation leads from the coronary sinus and great cardiac vein.

    Science.gov (United States)

    Wilkoff, Bruce L; Belott, Peter H; Love, Charles J; Scheiner, Avram; Westlund, Randy; Rippy, Marian; Krishnan, Mohan; Norlander, Barry E; Steinhaus, Bruce; Emmanuel, Janson; Zeller, Peter J

    2005-03-01

    Permanent leads with shocking coils for defibrillation therapy are sometimes implanted in the coronary sinus (CS) and great cardiac vein (GCV). These shocking coils, as documented by pathologic examination of animal investigations, often become tightly encapsulated by fibrosis and can be very difficult to remove. One of three configurations of the Guidant model 7109 Perimeter coronary sinus shocking lead was implanted into the distal portion of the GCV of 24 sheep for up to 14 months. Group 1 had unmodified coils (control), group 2 had coils backfilled with medical adhesive (MA), and Group 3 had coils coated with expanded polytetrafluoroethylene (ePTFE). Eighteen leads, three from each group at 6 and 14 months were transvenously extracted from the left jugular vein. The remaining six animals were not subject to extraction. All animals were euthanized for pathological and microscopic examination. All six of the control, three of the MA, and one of the ePTFE leads required the use of an electrosurgical dissection sheath (EDS) for extraction. Five control, two MA, and none of the ePTFE leads had significant fibrotic attachments to the shocking coils. Significant trauma was observed at necropsy for those leads requiring the use of the EDS for extraction. Tissue ingrowth is a major impediment to the removal of defibrillation leads implanted in the CS and GCV of sheep. Reduction of tissue ingrowth by coating the shocking coils with ePTFE or by backfilling with MA facilitates transvenous lead removal with reduced tissue trauma.

  19. Elastomeric degradable biomaterials by photopolymerization-based CAD-CAM for vascular tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Baudis, Stefan; Nehl, Franziska; Ligon, S Clark; Liska, Robert [Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163MC, A-1060 Vienna (Austria); Nigisch, Anneliese; Bernhard, David [Department of Surgery, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Bergmeister, Helga [Core Unit for Biomedical Research, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Stampfl, Juergen, E-mail: robert.liska@tuwien.ac.at [Institute of Material Science and Technology, Vienna University of Technology, Favoritenstrasse 9-11, A-1040 Vienna (Austria)

    2011-10-15

    A predominant portion of mortalities in industrial countries can be attributed to diseases of the cardiovascular system. In the last decades great efforts have been undertaken to develop materials for artificial vascular constructs. However, bio-inert materials like ePTFE or PET fail as material for narrow blood vessel replacements (coronary bypasses). Therefore, we aim to design new biocompatible materials to overcome this. In this paper we investigate the use of photoelastomers for artificial vascular constructs since they may be precisely structured by means of additive manufacturing technologies. Hence, 3D computer aided design and manufacturing technologies (CAD-CAM) offer the possibility of creating cellular structures within the grafts that might favour ingrowth of tissue. Different monomer formulations were screened concerning their suitability for this application but all had drawbacks, especially concerning the suture tear resistance. Therefore, we chose to modify the original network architecture by including dithiol chain transfer agents which effectively co-react with the acrylates and reduce crosslink density. A commercial urethane diacrylate was chosen as base monomer. In combination with reactive diluents and dithiols, the properties of the photopolymers could be tailored and degradability could be introduced. The optimized photoelastomers were in good mechanical accordance with native blood vessels, showed good biocompatibility in in vitro tests, degraded similar to poly(lactic acid) and were successfully manufactured with the 3D CAD-CAM technology.

  20. 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.

  1. 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

    International Nuclear Information System (INIS)

    Jeong, Young An; Kim, Sung Hoon; Cheon, Kyung Ah; Park, Young Ha; Jeong, Soo Kyo; Song Moon Kab

    1999-01-01

    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

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

    Science.gov (United States)

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

    2017-10-01

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

  3. [Treatment of the infected wound with exposed silver-ring vascular graft and delayed Thiersch method of skin transplant covering ].

    Science.gov (United States)

    Nenezić, Dragoslav; Pandaitan, Simon; Ilijevski, Nenad; Matić, Predrag; Gajin, Predag; Radak, Dorde

    2005-01-01

    Although the incidence of prosthetic infection is low (1%-6%), the consequences (limb loss or death) are dramatic for a patient, with high mortality rate (25%-75%) and limb loss in 40%-75% of cases. In case of Szilagyi's grade III infection, standard procedure consists of the excision of prosthesis and wound debridement. Alternative method is medical treatment. This is a case report of a patient with prosthetic infection of Silver-ring graft, used for femoropopliteal reconstruction, in whom an extreme skin necrosis developed in early postoperative period. This complication was successfully treated medically. After repeated debridement and wound-packing, the wound was covered using Thiersch skin graft.

  4. Expression of bone morphogenic protein 2/4, transforming growth factor-β1, and bone matrix protein expression in healing area between vascular tibia grafts and irradiated bone-experimental model of osteonecrosis

    International Nuclear Information System (INIS)

    Schultze-Mosgau, Stefan; Lehner, Bernhard; Roedel, Franz; Wehrhan, Falk; Amann, Kerstin; Kopp, Juergen; Thorwarth, Michael; Nkenke, Emeka; Grabenbauer, Gerhard

    2005-01-01

    Purpose: For the surgical treatment of osteoradionecrosis after multimodal therapy of head-and-neck cancers, free vascular bone grafts are used to reconstruct osseous structures in the previously irradiated graft bed. Reduced, or even absent osseous healing in the transition area between the vascular graft and the irradiated graft bed represents a clinical problem. Inflammatory changes and fibrosis lead to delayed healing, triggered by bone morphogentic protein 2/4 (BMP2/4) and transforming growth factor (TGF)-β 1 . Given the well-known fibrosis-inducing activity of TGF-β 1 , an osteoinductive effect has been reported for BMP2/4. However, the influence of irradiation (RT) on this cytokine expression remains elusive. Therefore, the aim of the present in vivo study was to analyze the expression of BMP2/4, TGF-β 1 , collagen I, and osteocalcin in the transition area between the bone graft and the graft bed after RT. Methods and materials: Twenty Wistar rats (male, weight 300-500 g) were used in this study. A free vascular tibia graft was removed in all rats and maintained pedicled in the groin region. Ten rats underwent RT with 5 x 10 Gy to the right tibia, the remainder served as controls. After 4 weeks, the previously removed tibia grafts were regrafted into the irradiated (Group 1) and nonirradiated (Group 2) graft beds. The interval between RT and grafting was 4 weeks. After a 4-week osseous healing period, the bone grafts were removed, and the transition area between the nonirradiated graft and the irradiated osseous graft bed was examined histomorphometrically (National Institutes of Health imaging program) and immunohistochemically (avidin-biotin-peroxidase complex) for the expression of BMP2/4, TGF-β 1 , collagen I, and osteocalcin. Results: Absent or incomplete osseous healing of the graft was found in 9 of 10 rats after RT with 50 Gy and in 1 of 10 of the rats with nonirradiated osseous grafts. Histomorphometrically, the proportion of osseous healing in

  5. Increased Pathogen Identification in Vascular Graft Infections by the Combined Use of Tissue Cultures and 16S rRNA Gene Polymerase Chain Reaction

    Directory of Open Access Journals (Sweden)

    Evelyne Ajdler-Schaeffler

    2018-06-01

    Full Text Available Background: Vascular graft infections (VGI are difficult to diagnose and treat, and despite redo surgery combined with antimicrobial treatment, outcomes are often poor. VGI diagnosis is based on a combination of clinical, radiological, laboratory and microbiological criteria. However, as many of the VGI patients are already under antimicrobial treatment at the time of redo surgery, microbiological identification is often difficult and bacterial cultures often remain negative rendering targeted treatment impossible. We aimed to assess the benefit of 16S rRNA gene polymerase chain reaction (broad-range PCR for better microbiological identification in patients with VGI.Methods: We prospectively analyzed the clinical, microbiological, and treatment data of patients enrolled in the observational Vascular Graft Cohort Study (VASGRA, University Hospital Zurich, Switzerland. The routine diagnostic work-up involved microbiological cultures of minced tissue samples, and the use of molecular techniques in parallel. Patient-related and microbiological data were assessed in descriptive analyses, and we calculated sensitivity, specificity, negative and positive predictive value for broad-range 16S rRNA gene PCR versus culture (considered as gold standard.Results: We investigated 60 patients (median age 66 years (Interquartile range [IQR] 59–75 with confirmed VGI between May 2013 and July 2017. The prevalence of antimicrobial pretreatment at the time of sampling was high [91%; median days of antibiotics 7 days (IQR 1–18]. We investigated 226 microbiological specimens. Thereof, 176 (78% were culture-negative and 50 (22% were culture-positive. There was a concordance of 70% (158/226 between conventional culture and broad-range PCR (sensitivity 58% (95% CI 43–72; specificity 74% (67–80%. Among the group of 176 culture-negative specimens, 46 specimens were broad-range PCR-positive resulting in identification of overall 69 species. Among the culture and

  6. 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.

  7. 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

  8. Alterations in plasma soluble vascular endothelial growth factor receptor-1 (sFlt-1 concentrations during coronary artery bypass graft surgery: relationships with post-operative complications

    Directory of Open Access Journals (Sweden)

    Orsel Isabelle

    2008-04-01

    Full Text Available Abstract Background Plasma concentrations of sFlt-1, the soluble form of the vascular endothelial growth factor receptor (VEGF, markedly increase during coronary artery bypass graft (CABG surgery with extracorporeal circulation (ECC. We investigated if plasma sFlt-1 values might be related to the occurrence of surgical complications after CABG. Methods Plasma samples were collected from the radial artery catheter before vascular cannulation and after opening the chest, at the end of ECC just before clamp release, after cross release, after weaning from ECC, at the 6th and 24th post-operative hour. Thirty one patients were investigated. The presence of cardiovascular, haematological and respiratory dysfunctions was prospectively assessed. Plasma sFlt-1 levels were measured with commercially ELISA kits. Results Among the 31 investigated patients, 15 had uneventful surgery. Patients with and without complications had similar pre-operative plasma sFlt-1 levels. Lowered plasma sFlt-1 levels were observed at the end of ECC in patients with haematological (p = 0.001, ANOVA or cardiovascular (p = 0.006 impairments, but not with respiratory ones (p = 0.053, as compared to patients with uneventful surgery. Conclusion These results identify an association between specific post-CABG complication and the lower release of sFlt-1 during ECC. sFlt-1-induced VEGF neutralisation might, thus, be beneficial to reduce the development of post-operative adverse effects after CABG.

  9. 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.

  10. 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.

  11. Culture of Iris Pigment Epithelial Cells on Expanded-Polytetrafluroethylene (ePTFE Substrates for the Treatment of Age-Related Macular Degeneration

    Directory of Open Access Journals (Sweden)

    S Nian

    2011-05-01

    Full Text Available Introduction: Transplantation of an intact differentiated retinal pigment epithelial (RPE cell layer may provide a means to treat Age-Related Macular Degeneration (AMD. However, harvesting RPE cells can be a technically complicated procedure. Our current work aimed to prepare intact differentiated iris pigment epithelial (IPE cell layers, which are easy to obtain and have the same embryonic origin and similar properties as RPE cells, on ePTFE substrates for transplantation purposes to rescue deteriorated photoreceptors in AMD. Methods: IPE cells isolated from rat eyes were seeded on different substrates, including fibronectin n-heptylamine (HA ePTFE substrates, HA ePTFE substrates, ePTFE substrates and fibronectin tissue culture polystyrene (TCPS as control. Cell number and morphology were assessed at each time interval. The formation of tight junction was examined by immunostaining of junction proteins. Results: An obvious increasing trend of cell number was observed in IPE cells on fibronectin n-heptylamine (HA ePTFE substrate, exhibiting heavy pigmentation and epithelial morphology. At Day 28, tight junction formation was indicated by cell-cell junctional proteins along cell borders. Conclusion: Harvested IPE cells cultured on fibronectin HA-ePTFE substrates can differentiate and form a cell monolayer that may be suitable for transplantation.

  12. Ionizing radiation effects on ISS ePTFE jacketed cable assembly

    Science.gov (United States)

    Koontz, S. L.; Golden, J. L.; Lorenz, M. J.; Pedley, M. D.

    2003-09-01

    Polytetrafluoroethylene (PTFE), which is susceptible to embrittlement by ionizing radiation, is used as a primary material in the Mobile Transporter's (MT) Trailing Umbilical System (TUS) cable on the International Space Station (ISS). The TUS cable provides power and data service between the ISS truss and the MT. The TUS cable is normally stowed in an uptake reel and is fed out to follow the MT as it moves along rails on the ISS truss structure. For reliable electrical and mechanical performance, TUS cable polymeric materials must be capable of >3.5% elongation without cracking or breaking. The MT TUS cable operating temperature on ISS is expected to range between -100°C and +130°C. The on-orbit functional life requirement for the MT TUS cable is 10 years. Analysis and testing were performed to verify that the MT TUS cable would be able to meet full-life mechanical and electrical performance requirements, despite progressive embrittlement by the natural ionizing radiation environment. Energetic radiation belt electrons (trapped electrons) are the principal contributor to TUS cable radiation dose. TUS cable specimens were irradiated, in vacuum, with both energetic electrons and gamma rays. Electron beam energy was chosen to minimize charging effects on the non-conductive ePTFE (expanded PTFE) targets. Tensile testing was then performed, over the expected range of operating temperatures, as a function of radiation dose. When compared to the expected in-flight radiation dose/depth profile, atomic oxygen (AO) erosion of the radiation damaged TUS cable jacket surfaces is more rapid than the development of radiation induced embrittlement of the same surfaces. Additionally, the layered construction of the jacket prevents crack growth propagation, leaving the inner layer material compliant with the design elongation requirements. As a result, the TUS cable insulation design was verified to meet performance life requirements.

  13. 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.

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

    Directory of Open Access Journals (Sweden)

    Jo Nadine Fleming

    2009-07-01

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

  15. Healthcare-associated prosthetic heart valve, aortic vascular graft, and disseminated Mycobacterium chimaera infections subsequent to open heart surgery.

    Science.gov (United States)

    Kohler, Philipp; Kuster, Stefan P; Bloemberg, Guido; Schulthess, Bettina; Frank, Michelle; Tanner, Felix C; Rössle, Matthias; Böni, Christian; Falk, Volkmar; Wilhelm, Markus J; Sommerstein, Rami; Achermann, Yvonne; Ten Oever, Jaap; Debast, Sylvia B; Wolfhagen, Maurice J H M; Brandon Bravo Bruinsma, George J; Vos, Margreet C; Bogers, Ad; Serr, Annerose; Beyersdorf, Friedhelm; Sax, Hugo; Böttger, Erik C; Weber, Rainer; van Ingen, Jakko; Wagner, Dirk; Hasse, Barbara

    2015-10-21

    We identified 10 patients with disseminated Mycobacterium chimaera infections subsequent to open-heart surgery at three European Hospitals. Infections originated from the heater-cooler unit of the heart-lung machine. Here we describe clinical aspects and treatment course of this novel clinical entity. Interdisciplinary care and follow-up of all patients was documented by the study team. Patients' characteristics, clinical manifestations, microbiological findings, and therapeutic measures including surgical reinterventions were reviewed and treatment outcomes are described. The 10 patients comprise a 1-year-old child and nine adults with a median age of 61 years (range 36-76 years). The median duration from cardiac surgery to diagnosis was 21 (range 5-40) months. All patients had prosthetic material-associated infections with either prosthetic valve endocarditis, aortic graft infection, myocarditis, or infection of the prosthetic material following banding of the pulmonary artery. Extracardiac manifestations preceded cardiovascular disease in some cases. Despite targeted antimicrobial therapy, M. chimaera infection required cardiosurgical reinterventions in eight patients. Six out of 10 patients experienced breakthrough infections, of which four were fatal. Three patients are in a post-treatment monitoring period. Healthcare-associated infections due to M. chimaera occurred in patients subsequent to cardiac surgery with extracorporeal circulation and implantation of prosthetic material. Infections became clinically apparent after a time lag of months to years. Mycobacterium chimaera infections are easily missed by routine bacterial diagnostics and outcome is poor despite long-term antimycobacterial therapy, probably because biofilm formation hinders eradication of pathogens. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  16. Skin graft

    Science.gov (United States)

    Skin transplant; Skin autografting; FTSG; STSG; Split thickness skin graft; Full thickness skin graft ... donor site. Most people who are having a skin graft have a split-thickness skin graft. This takes ...

  17. 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.

  18. 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...

  19. Comparison of TEVAR resin beads, PAN fibers, and ePTFE membranes as a solid support for Aliquat-336 in immobilized liquid extraction chromatography for separation of actinides

    International Nuclear Information System (INIS)

    Joe Dauner; Steve Workman

    2012-01-01

    The following paper covers a comparison of two new systems to traditional TEVA R resin systems for the analytical separation of actinides by immobilized liquid-liquid extraction using Aliquat-336. The new systems are using expanded polytetrafluroethane (ePTFE) membrane or polyacrylonitrile (PAN) fibers as the solid support. The systems are compared in two ways. First in how much Aliquat-336 they contain with the Vs, ratio of volume of Aliquat-336 to volume of polymeric support, being 0.158, 0.483, and 0.590 for the TEVA R resin, PAN fibers, and the ePTFE systems, respectively. The second comparison is in their performance capacity of extraction of uranyl chloride anion complex. The fiber and resins systems show similar capacities, and the membrane system being an order of magnitude less than the other systems. A cost comparison demonstrates the savings advantages of using a fiber based support compared with resin and membrane support systems. (author)

  20. 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

  1. Wound Healing and ndash; A Proteomic Analysis of the Effect of Erythropoietin on Granulation Tissue Isolated from ePTFE Implants

    Directory of Open Access Journals (Sweden)

    Bekka Christensen

    2014-02-01

    Conclusion: Daily injection of recombinant human erythropoietin of 1000 IU/kg alters the protein expression of GAPDH, ENOA and TPIS in granulation tissue from wounds on postoperative day 9. The successful combination of proteomic analysis of wound tissue and the ePTFE wound model could advance our knowledge of the complex healing process. [Arch Clin Exp Surg 2014; 3(1.000: 26-33

  2. 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.

  3. Vascularised Fibular Graft for a Radial Defect following Tumour ...

    African Journals Online (AJOL)

    HP

    The mass was located on the radial aspect of the distal right ... modification, internal or external fixation with bone grafting, structural grafts of ... Our index case report demonstrates that free vascularized fibular graft transfer is a feasible option ... structural support, the potential for graft hypertrophy, relative resistance to ...

  4. Current Role of Imaging in Diagnosing Aortic Graft Infections

    NARCIS (Netherlands)

    Bruggink, Janneke L. M.; Slart, Riemer H. J. A.; Pol, Jillis A.; Reijnen, Michel M. P. J.; Zeebregts, Clark J.

    2011-01-01

    Vascular prosthetic graft infection is a rare but serious complication after aortic graft replacement, with high morbidity and mortality rates. Therefore, adequate diagnostics are needed to detect and treat these infections as early as possible. Several imaging modalities provide different

  5. 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.

  6. 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.

  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. Revascularization of diaphyseal bone segments by vascular bundle implantation.

    Science.gov (United States)

    Nagi, O N

    2005-11-01

    Vascularized bone transfer is an effective, established treatment for avascular necrosis and atrophic or infected nonunions. However, limited donor sites and technical difficulty limit its application. Vascular bundle transplantation may provide an alternative. However, even if vascular ingrowth is presumed to occur in such situations, its extent in aiding revascularization for ultimate graft incorporation is not well understood. A rabbit tibia model was used to study and compare vascularized, segmental, diaphyseal, nonvascularized conventional, and vascular bundle-implanted grafts with a combination of angiographic, radiographic, histopathologic, and bone scanning techniques. Complete graft incorporation in conventional grafts was observed at 6 months, whereas it was 8 to 12 weeks with either of the vascularized grafts. The pattern of radionuclide uptake and the duration of graft incorporation between vascular segmental bone grafts (with intact endosteal blood supply) and vascular bundle-implanted segmental grafts were similar. A vascular bundle implanted in the recipient bone was found to anastomose extensively with the intraosseous circulation at 6 weeks. Effective revascularization of bone could be seen when a simple vascular bundle was introduced into a segment of bone deprived of its normal blood supply. This simple technique offers promise for improvement of bone graft survival in clinical circumstances.

  9. 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 ...

  10. Skin Graft

    OpenAIRE

    Shimizu, Ruka; Kishi, Kazuo

    2012-01-01

    Skin graft is one of the most indispensable techniques in plastic surgery and dermatology. Skin grafts are used in a variety of clinical situations, such as traumatic wounds, defects after oncologic resection, burn reconstruction, scar contracture release, congenital skin deficiencies, hair restoration, vitiligo, and nipple-areola reconstruction. Skin grafts are generally avoided in the management of more complex wounds. Conditions with deep spaces and exposed bones normally require the use o...

  11. Implant surface preparation in the surgical treatment of experimental peri-implantitis with autogenous bone graft and ePTFE membrane in cynomolgus monkeys

    DEFF Research Database (Denmark)

    Schou, Søren; Holmstrup, Palle; Jørgensen, Torben

    2003-01-01

    peri-implantitis; treatment; implant surface preparation; nonhuman primates; histology; stereology......peri-implantitis; treatment; implant surface preparation; nonhuman primates; histology; stereology...

  12. 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.

  13. 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.

  14. An in vivo comparative study of the e-polytetrafluoroethylene vascular prostheses: Vitaflon and Gore-Tex.

    Science.gov (United States)

    Dobrova, N B; Gorodkov, A J; Sidorenko, E S; Schekhter, A B; Baquey, C

    1999-12-01

    A comparative study was performed in order to validate new Russian e-PTFE vascular prostheses Vitaflon (St. Petersburg, Russia). The Gore-Tex prostheses were chosen as a referential model. The prostheses were implanted in the venous and arterial positions in 13 dog experiments. After the implantation time was over a comprehensive histological and histochemical examination of excized specimens was performed. It was demonstrated that there is no difference in healing and functional properties between the two studied prostheses. Copyright 1999 Kluwer Academic Publishers

  15. Pancreas grafts

    International Nuclear Information System (INIS)

    Hahn, D.; Buell, U.; Land, W.; Unertl, K.

    1981-01-01

    Perfusion studies with sup(99m)Tc-DTPA, which has hitherto been used routinely to investigate renal grafts, have also proved useful for monitoring the perfusion of pancreas grafts. A total perfusion failure is equally reliably demonstrable as in renal grafts. Quantitatively smaller perfusion alterations can be demonstrated by monitoring the course. It seems possible to differentiate the salivary edema of a rejection reaction, well known from animal experiments, with the help of other paramters (e.g. creatinine). Further clinical studies are however necessary to confirm these results. (orig.) [de

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

    Science.gov (United States)

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

    2013-12-15

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

  17. 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.

  18. 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,

  19. 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

  20. 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...

  1. 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.

  2. Primary nerve grafting: A study of revascularization.

    Science.gov (United States)

    Chalfoun, Charbel; Scholz, Thomas; Cole, Matthew D; Steward, Earl; Vanderkam, Victoria; Evans, Gregory R D

    2003-01-01

    It was the purpose of this study to evaluate the revascularization of primary nerve repair and grafts using orthogonal polarization spectral (OPS) (Cytometrix, Inc.) imaging, a novel method for real-time evaluation of microcirculatory blood flow. Twenty male Sprague Dawley rats (250 g) were anesthetized with vaporized halothane and surgically prepared for common peroneal nerve resection. Group I animals (n = 10) underwent primary neurorraphy following transection, utilizing a microsurgical technique with 10-0 nylon suture. Group II (n = 10) animals had a 7-mm segment of nerve excised, reversed, and subsequently replaced as a nerve graft under similar techniques. All animals were evaluated using the OPS imaging system on three portions (proximal, transection site/graft, and distal) of the nerve following repair or grafting. Reevaluation of 5 animals randomly selected from each group using the OPS imaging system was again performed on days 14 and 28 following microsurgical repair/grafting. Values were determined by percent change in vascularity of the common peroneal nerve at 0 hr following surgery. Real-time evaluation of blood flow was utilized as an additional objective criterion. Percent vascularity in group I and II animals increased from baseline in all segments at day 14. By day 28, vascularity in nerves of group I rats decreased in all segments to values below baseline, with the exception of the transection site, which remained at a higher value than obtained directly after surgical repair. In group II animals, vascularity remained above baseline in all segments except the distal segment, which returned to vascularity levels similar to those at 0 hr. Further, occlusion of the vessels demonstrated in the graft and distal segments following initial transection appeared to be corrected. This study suggests that revascularization may occur via bidirectional inosculation with favored proximal vascular growth advancement. The use of real-time imaging offers a

  3. 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.

  4. 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.

  5. Using Polymeric Scaffolds for Vascular Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Alida Abruzzo

    2014-01-01

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

  6. 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.

  7. 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

  8. Bone Graft Alternatives

    Science.gov (United States)

    ... Spine Treatment Spondylolisthesis BLOG FIND A SPECIALIST Treatments Bone Graft Alternatives Patient Education Committee Patient Education Committee ... procedure such as spinal fusion. What Types of Bone Grafts are There? Bone grafts that are transplanted ...

  9. 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).

  10. Feasibility of the Use of RapiGraft and Skin Grafting in Reconstructive Surgery

    Directory of Open Access Journals (Sweden)

    Jung Dug Yang

    2016-09-01

    Full Text Available BackgroundSkin grafting is a relatively simple and thus widely used procedure. However, the elastic and structural quality of grafted skin is poor. Recently, various dermal substitutes have been developed to overcome this disadvantage of split-thickness skin grafts. The present study aims to determine the feasibility of RapiGraft as a new dermal substitute.MethodsThis prospective study included 20 patients with partial- or full-thickness skin defects; the patients were enrolled between January 2013 and March 2014. After skin defect debridement, the wound was divided into two parts by an imaginary line. Split-thickness skin grafting alone was performed on one side (group A, and RapiGraft and split-thickness skin grafting were used on the other side (group B. All patients were evaluated using photographs and self-questionnaires. The Manchester scar scale (MSS, a chromameter, and a durometer were used for the scar evaluation. The average follow-up period was 6 months.ResultsThe skin graft take rates were 93% in group A and 89% in group B, a non-significant difference (P=0.082. Statistically, group B had significantly lower MSS, vascularity, and pigmentation results than group A (P<0.05 for all. However, the groups did not differ significantly in pliability (P=0.155.ConclusionsThe present study indicates that a simultaneous application of RapiGraft and a split-thickness skin graft is safe and yields improved results. Therefore, we conclude that the use of RapiGraft along with skin grafting will be beneficial for patients requiring reconstructive surgery.

  11. 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.

  12. 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

  13. Dramatic Vascular Course of Behcet's Disease

    International Nuclear Information System (INIS)

    Elsharawy, Mohamed A.; Hassan, Khairi A.; Al-Awami, Majed; Al-Mulhim, Fatma A.

    2004-01-01

    Vascular involvement in Behcet's disease is rare (approximately 14% venous and 1.6% arterial), serious and recurrent. We report a case of Behcet's disease with deep venous thrombosis and right iliac pseudoaneurysm which was repaired with polytetrafluoroethylene (PTFE) graft. The patient received warfarin, aspirin, clopidogrel, immunosupressive and corticosteroids. Two months later the patient developed manifestations of superior vena cava thrombosis and the graft was blocked. Three months later, ischemia of the right foot deteriorated and left femoral artery crossover (PTFE) graft was performed. (author)

  14. 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)

  15. 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

  16. Hypertrophic osteoarthropathy of one leg - a sign of aortic graft infection

    Energy Technology Data Exchange (ETDEWEB)

    Spruijt, S.; Krijgsman, A.A. [Department of Orthopaedic and Trauma Surgery, Elkerliek Hospital, Helmond (Netherlands); Broek, J.A.C. van den [Department of Radiology, Elkerliek Hospital, Helmond (Netherlands); Tutein Nolthenius-Puylaert, M.C.B.J.E. [Department of Pathology, Elkerliek Hospital, Helmond (Netherlands)

    1999-04-01

    We report a rare case of hypertrophic osteoarthropathy (HOA) confined to the right leg secondary to aortic graft infection. The development of HOA exclusively localized to areas distal to a vascular prosthesis may be the presenting manifestation of graft infection and a crucial diagnostic clue in the early detection of vascular graft infection. HOA is diagnosed by its characteristic radiographic and scintigraphic pattern. Most prosthetic, especially aortic, graft infections are uniformly fatal if not treated by aggressive surgical and antibiotic therapy. Recognition of this uncommon association may facilitate an early diagnosis, which usually requires immediate surgical therapy. (orig.) With 6 figs., 28 refs.

  17. Hypertrophic osteoarthropathy of one leg - a sign of aortic graft infection

    International Nuclear Information System (INIS)

    Spruijt, S.; Krijgsman, A.A.; Broek, J.A.C. van den; Tutein Nolthenius-Puylaert, M.C.B.J.E.

    1999-01-01

    We report a rare case of hypertrophic osteoarthropathy (HOA) confined to the right leg secondary to aortic graft infection. The development of HOA exclusively localized to areas distal to a vascular prosthesis may be the presenting manifestation of graft infection and a crucial diagnostic clue in the early detection of vascular graft infection. HOA is diagnosed by its characteristic radiographic and scintigraphic pattern. Most prosthetic, especially aortic, graft infections are uniformly fatal if not treated by aggressive surgical and antibiotic therapy. Recognition of this uncommon association may facilitate an early diagnosis, which usually requires immediate surgical therapy. (orig.)

  18. 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

  19. Intravascular stent graft with polyurethane and metallic stent: experimental study

    International Nuclear Information System (INIS)

    Do, Young Soo; Lee, Won Jae; Kim, Boo Kyung Han; Park, Jae Hyung; Lee, Hak Jong; Lee, Sang Hyun; Kim, Sung Hyun; Kim, Jong Won; Ha, Jongwon

    1997-01-01

    To evaluate the usefulness of a new model of the stent graft, and of tissue response related to placement of the stent graft. The stent graft was constructed from polyurethane (Pellethane) graft and Hanaro stent(12mm in diameter, 45mm in length, 10 bends). A stent grafts was inserted into the lower thoracic aorta in each of six adult mongrel dogs(body weight, 12-16kg). At one, two, four, and six months, follow-up studies of angiography and spiral CT angiography were preformed to evaluate wascular patency, vascular stenosis, and thrombus formation. Two dogs were sacrificed at 1month, 2months, and 6months after insertion of the stent graft and macroscopic, light microscopic, and scanning electron microscopic examinations of the aortic segment including the stent graft were performed to evaluate intimal hyperplasia, endothelial growth to the graft, and thrombus formation. During follow-up at one, two, four, and six months, angiography or spiral CT angiography showed 20-100% luminal stenosis or occlusion of the lower thoracic aorta by the thrombus and perigraft leaks in three dogs(50%), and collateral vessels caused by occlusion of the aorta in two (33.3%). On gross examination, there were thrombi of 1-5mm thickness at the graft portions in all dogs, and this thickness gradually increased. The mean thickness of intimal hyperplasia at the stent portion gradually increased from 120μm to 227μm and the mean thickness of intimal hyperplasia at the graft portion from 93μm to 914μm. This thickness was greater at the graft portion than at the stent portion. Scanning electron microscopy showed elliptical endothelial lining on the neointimal surfaces at each end of the graft. Thrombi caused stenosis or occlusion of the stent graft. In order for such a graft to be ideal, further study is needed

  20. 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

  1. Skin graft - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100100.htm Skin graft - series—Normal anatomy To use the sharing features ... entire body, and acts as a protective barrier. Skin grafts may be recommended for: Extensive wounds Burns Specific ...

  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. Vascular access for home haemodialysis.

    Science.gov (United States)

    Al Shakarchi, Julien; Day, C; Inston, N

    2018-03-01

    Home haemodialysis has been advocated due to improved quality of life. However, there are very little data on the optimum vascular access for it. A retrospective cohort study was carried on all patients who initiated home haemodialysis between 2011 and 2016 at a large university hospital. Access-related hospital admissions and interventions were used as primary outcome measures. Our cohort consisted of 74 patients. On initiation of home haemodialysis, 62 individuals were using an arteriovenous fistula as vascular access, while the remaining were on a tunnelled dialysis catheter. Of the 12 patients who started on a tunnelled dialysis catheter, 5 were subsequently converted to either an arteriovenous fistula ( n = 4) or an arteriovenous graft ( n = 1). During the period of home haemodialysis use, four arteriovenous fistula failed or thrombosed with patients continuing on home haemodialysis using an arteriovenous graft ( n = 3) or a tunnelled dialysis catheter ( n = 1). To maintain uninterrupted home haemodialysis, interventional rates were 0.32 per arteriovenous fistula/arteriovenous graft access-year and 0.4 per tunnelled dialysis catheter access-year. Hospital admission rates for patients on home haemodialysis were 0.33 per patient-year. Our study has shown that home haemodialysis can be safely and independently performed at home within a closely managed home haemodialysis programme. The authors also advocate the use of arteriovenous fistulas for this cohort of patients due to both low complication and intervention rates.

  4. The Incidence and Risk Factors for Lower Limb Skin Graft Failure

    Directory of Open Access Journals (Sweden)

    Sumeet Reddy

    2014-01-01

    Full Text Available Lower limb skin grafts are thought to have higher failure rates than skin grafts in other sites of the body. Currently, there is a paucity of literature on specific factors associated with lower limb skin graft failure. We present a series of 70 lower limb skin grafts in 50 patients with outcomes at 6 weeks. One-third of lower limb skin grafts went on to fail with increased BMI, peripheral vascular disease, and immunosuppressant medication use identified as significant risk factors.

  5. The protective effect of vein cuffed anastomoses is not mechanical in origin.

    Science.gov (United States)

    Norberto, J J; Sidawy, A N; Trad, K S; Jones, B A; Neville, R F; Najjar, S F; Sidawy, M K; DePalma, R G

    1995-04-01

    Intimal hyperplasia (IH) is a proliferative process of vascular smooth muscle cells that occurs after an arterial injury, particularly at outflow anastomoses of prosthetic bypass grafts. IH causes stenosis that leads ultimately to graft flow reduction and thrombosis. We have demonstrated previously that vein cuff interposition between an expanded polytetrafluoroethylene (e-PTFE) graft and artery at distal anastomoses diminished IH formation in the arterial outflow as compared with noncuffed anastomoses. Improved long-term patency rates associated with the placement of an interposition vein cuff at the distal anastomosis of e-PTFE grafts to infrageniculate arteries have also been demonstrated clinically. This study examined the mechanical factors that may contribute to the protective effect of cuffed anastomoses. These factors include the expansibility of the vein cuff as compared with e-PTFE, as well as the angle of the cuffed anastomosis. Compatible animals were selected by use of platelet aggregation studies. Nine dogs, group A, received a 4 mm e-PTFE graft plus a 1 cm long interposition vein cuff at the distal anastomosis in the left carotid artery. The same procedure was done on the right side, and in addition the vein cuff was encircled by an e-PTFE jacket incorporated into the anastomosis to prevent the expansion of the vein cuff with arterial pulsation. To study the effect of distal anastomotic angle and geometry on the formation of IH, five dogs, group B, received a 4 mm e-PTFE graft in both sides. On the left, the distal anastomosis was performed between the graft and the artery at an acute angle as it is commonly done when a bypass graft is placed. On the right side a 1 cm long, 6 mm diameter e-PTFE segment was interposed between the artery and the graft at a perpendicular angle. This geometry mimicked the right angle of a vein cuff-to-artery anastomosis. After 10 weeks the grafts were harvested, and the thickness of IH was measured with an ocular

  6. Revascularization of autogenous skin grafts placed on irradiated tissue

    International Nuclear Information System (INIS)

    Ueda, M.; Torii, S.; Kaneda, T.; Oka, T.

    1982-01-01

    Vascular changes in rat skin after irradiation were examined microangiographically. Revascularization of the skin transplanted during the chronic stage after irradiation was also studied. The results obtained through these examinations revealed higher vascular densities at the acute and the subacute stages, and low values at the chronic stages compared with those of the control. Furthermore, when the skin grafts were transplanted to the irradiated beds in the chronic stage, primary revascularization was scant, and the inhibited capillary proliferation in the recipient sites prevented new vessel penetration. This explains why grafts transplanted to previously irradiated beds fail to survive

  7. Corneal Graft Rejection: Incidence and Risk Factors

    Directory of Open Access Journals (Sweden)

    Alireza Baradaran-Rafii

    2008-12-01

    Full Text Available

    PURPOSE: To determine the incidence and risk factors of late corneal graft rejection after penetrating keratoplasty (PKP. METHODS: Records of all patients who had undergone PKP from 2002 to 2004 without immunosuppressive therapy other than systemic steroids and with at least one year of follow up were reviewed. The role of possible risk factors such as demographic factors, other host factors, donor factors, indications for PKP as well as type of rejection were evaluated. RESULTS: During the study period, 295 PKPs were performed on 286 patients (176 male, 110 female. Mean age at the time of keratoplasty was 38±20 (range, 40 days to 90 years and mean follow up period was 20±10 (range 12-43 months. Graft rejection occurred in 94 eyes (31.8% at an average of 7.3±6 months (range, 20 days to 39 months after PKP. The most common type of rejection was endothelial (20.7%. Corneal vascularization, regrafting, anterior synechiae, irritating sutures, active inflammation, additional anterior segment procedures, history of trauma, uncontrolled glaucoma, prior graft rejection, recurrence of herpetic infection and eccentric grafting increased the rate of rejection. Patient age, donor size and bilateral transplantation had no significant influence on graft rejection. CONCLUSION: Significant risk factors for corneal graft rejection include

  8. Cytocompatibility of amine functionalized carbon nanoparticles grafted on polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Žáková, Pavlína, E-mail: pavlina.zakova@vscht.cz [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic); Slepičková Kasálková, Nikola [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic); Kolská, Zdeňka [Faculty of Science, J. E. Purkyně University, Ústí nad Labem (Czech Republic); Leitner, Jindřich [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic); Karpíšková, Jana; Stibor, Ivan [Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec (Czech Republic); Slepička, Petr; Švorčík, Václav [Department of Solid State Engineering, University of Chemistry and Technology, 166 28 Prague 6 (Czech Republic)

    2016-03-01

    Five types of amide–amine Carbon Nano-Particles (CNPs) were prepared by functionalization of CNPs and characterized by several analytical methods. The successful grafting of amines on CNPs was verified by X-ray photoelectron spectroscopy (XPS), organic elemental analysis and electrokinetic analysis. The size and morphology of CNPs were determined from transmission electron microscopy. The surface area and porosity of CNPs were examined by adsorption and desorption isotherms. Differential scanning calorimetry was used to investigate thermal stability of CNPs. The amount of bonded amine depends on its dimensionality arrangement. Surface area and pore volumes of CNPs decrease several times after individual amino-compound grafting. Selected types of functionalized CNPs were grafted onto a plasma activated surface of HDPE. The successful grafting of CNPs on the polymer surface was verified by XPS. Wettability was determined by contact angle measurements. Surface morphology and roughness were studied by atomic force microscopy. A dramatic decrease of contact angle and surface morphology was observed on CNP grafted polymer surface. Cytocompatibility of modified surfaces was studied in vitro, by determination of adhesion, proliferation and viability of vascular smooth muscle cells (VSMCs). Grafting of CNPs onto the polymer surface has a positive effect on the adhesion, proliferation and viability of VSMCs. - Highlights: • Amine functionalized CNPs were successfully grafted on HDPE surface. • Significant change to the positive zeta potential for grafted CNPs was induced. • Grafting of CNPs significantly enhanced cell cytocompatibility and viability. • Homogeneous distribution of cells with correct size was achieved.

  9. Matrix metalloproteinase inhibition reduces intimal hyperplasia in a porcine arteriovenous-graft model

    NARCIS (Netherlands)

    Rotmans, Joris I.; Velema, Evelyn; Verhagen, Hence J. M.; Blankensteijn, Jan D.; de kleijn, Dominique P. V.; Stroes, Erik S. G.; Pasterkamp, Gerard

    2004-01-01

    Background: The patency of arteriovenous (AV) polytetrafluoroethylene grafts for hemodialysis is impaired by intimal hyperplasia (IH) at the venous outflow tract. IH mainly consists of vascular smooth muscle cells, fibroblasts, and extracellular matrix proteins. Because matrix metalloproteinases

  10. Matrix metalloproteinase inhibition reduces intimal hyperplasia in a porcine arteriovenous-graft model.

    NARCIS (Netherlands)

    Rotmans, J.I.; Velema, E.; Verhagen, H.J.; Blankensteijn, J.D.; Kleijn, D.P. de; Stroes, E.S.; Pasterkamp, G.

    2004-01-01

    BACKGROUND: The patency of arteriovenous (AV) polytetrafluoroethylene grafts for hemodialysis is impaired by intimal hyperplasia (IH) at the venous outflow tract. IH mainly consists of vascular smooth muscle cells, fibroblasts, and extracellular matrix proteins. Because matrix metalloproteinases

  11. Matrix metalloproteinase inhibition reduces intimal hyperplasia in a porcine arteriovenous-graft model

    NARCIS (Netherlands)

    Rotmans, JI; Velema, E; Verhagen, HJM; Blankensteijn, JD; de Kleijn, DPV; Stroes, ESG; Pasterkamp, G

    Background: The patency of arteriovenous (AV) polytetrafluoroethylene grafts for hemodialysis is impaired by intimal hyperplasia (IH) at the venous outflow tract. IH mainly consists of vascular smooth muscle cells, fibroblasts, and extracellular matrix proteins. Because matrix metalloproteinases

  12. Laser-assisted fibrinogen bonding of umbilical vein grafts.

    Science.gov (United States)

    Oz, M C; Williams, M R; Souza, J E; Dardik, H; Treat, M R; Bass, L S; Nowygrod, R

    1993-06-01

    Despite success with autologous tissue welding, laser welding of synthetic vascular prostheses has not been possible. The graft material appears inert and fails to allow the collagen breakdown and electrostatic bonding that results in tissue welding. To develop a laser welding system for graft material, we repaired glutaraldehyde-tanned human umbilical cord vein graft incisions using laser-assisted fibrinogen bonding (LAFB) technology. Modified umbilical vein graft was incised transversely (1.2 cm). Incisions were repaired using sutures, laser energy alone, or LAFB. For LAFB, indocyanine green dye was mixed with human fibrinogen and the compound applied with forceps onto the weld site prior to exposure to 808 nm diode laser energy (power density 4.8 W/cm 2). Bursting pressures for sutured repairs (126.6 +/- 23.4 mm Hg) were similar to LAFB anastomoses (111.6 +/- 55.0 mm Hg). No evidence of collateral thermal injury to the graft material was noted. In vivo evaluation of umbilical graft bonding with canine arteries demonstrates that LAFB can reliably reinforce sutured anastomoses. The described system for bonding graft material with laser exposed fibrinogen may allow creation or reinforcement of vascular anastomoses in procedures where use of autologous tissue is not feasible.

  13. 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 ...

  14. Vascular Disorders

    Science.gov (United States)

    ... All Topics A-Z Videos Infographics Symptom Picker Anatomy Bones Joints Muscles Nerves Vessels Tendons About Hand Surgery What is a Hand Surgeon? What is a Hand Therapist? Media Find a Hand Surgeon Home Anatomy Vascular Disorders Email to a friend * required fields ...

  15. Nanotechnology in vascular tissue engineering: from nanoscaffolding towards rapid vessel biofabrication.

    Science.gov (United States)

    Mironov, Vladimir; Kasyanov, Vladimir; Markwald, Roger R

    2008-06-01

    The existing methods of biofabrication for vascular tissue engineering are still bioreactor-based, extremely expensive, laborious and time consuming and, furthermore, not automated, which would be essential for an economically successful large-scale commercialization. The advances in nanotechnology can bring additional functionality to vascular scaffolds, optimize internal vascular graft surface and even help to direct the differentiation of stem cells into the vascular cell phenotype. The development of rapid nanotechnology-based methods of vascular tissue biofabrication represents one of most important recent technological breakthroughs in vascular tissue engineering because it dramatically accelerates vascular tissue assembly and, importantly, also eliminates the need for a bioreactor-based scaffold cellularization process.

  16. 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

  17. 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.

  18. 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...

  19. 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.

  20. Surface modification and endothelialization of biomaterials as potential scaffolds for vascular tissue engineering applications.

    Science.gov (United States)

    Ren, Xiangkui; Feng, Yakai; Guo, Jintang; Wang, Haixia; Li, Qian; Yang, Jing; Hao, Xuefang; Lv, Juan; Ma, Nan; Li, Wenzhong

    2015-08-07

    Surface modification and endothelialization of vascular biomaterials are common approaches that are used to both resist the nonspecific adhesion of proteins and improve the hemocompatibility and long-term patency of artificial vascular grafts. Surface modification of vascular grafts using hydrophilic poly(ethylene glycol), zwitterionic polymers, heparin or other bioactive molecules can efficiently enhance hemocompatibility, and consequently prevent thrombosis on artificial vascular grafts. However, these modified surfaces may be excessively hydrophilic, which limits initial vascular endothelial cell adhesion and formation of a confluent endothelial lining. Therefore, the improvement of endothelialization on these grafts by chemical modification with specific peptides and genes is now arousing more and more interest. Several active peptides, such as RGD, CAG, REDV and YIGSR, can be specifically recognized by endothelial cells. Consequently, graft surfaces that are modified by these peptides can exhibit targeting selectivity for the adhesion of endothelial cells, and genes can be delivered by targeting carriers to specific tissues to enhance the promotion and regeneration of blood vessels. These methods could effectively accelerate selective endothelial cell recruitment and functional endothelialization. In this review, recent developments in the surface modification and endothelialization of biomaterials in vascular tissue engineering are summarized. Both gene engineering and targeting ligand immobilization are promising methods to improve the clinical outcome of artificial vascular grafts.

  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. 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.

  3. 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

  4. 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.

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

    Directory of Open Access Journals (Sweden)

    Zhenghai Mo

    2018-02-01

    Full Text Available 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.

  7. Angiogenesis Research to Improve Therapies for Vascular Leak Syndromes, Intra-Abdominal Adhesions, and Arterial Injuries

    National Research Council Canada - National Science Library

    Folkman, Judah; Puder, Mark; Bischoff, Joyce

    2006-01-01

    ...) to develop angiogenesis inhibitors which would inhibit post-operative abdominal adhesions; and (iii) to isolate endothelial progenitor cells from blood capable of being expanded in vitro and applied to vascular grafts...

  8. Angiogenesis Research to Improve Therapies for Vascular Leak Syndromes, Intra-Abdominal Adhesions, and Arterial Injuries

    National Research Council Canada - National Science Library

    Folkman, Judah; Puder, Mark; Bischoff, Joyce

    2007-01-01

    ...) to develop angiogenesis inhibitors which would inhibit post-operative abdominal adhesions; and, (iii) to isolate endothelial progenitor cells from blood, capable of being expanded in vitro and applied to vascular grafts...

  9. Angiogenesis Research to Improve Therapies for Vascular Leak Syndromes, Intra-abdominal Adhesions, and Arterial Injuries

    National Research Council Canada - National Science Library

    Folkman, Judah

    2008-01-01

    ...) to develop angiogenesis inhibitors which would inhibit post-operative abdominal adhesions; and, (iii) to isolate endothelial progenitor cells from blood, capable of being expanded in vitro and applied to vascular grafts...

  10. 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

  11. Bone graft revascularization strategies

    NARCIS (Netherlands)

    Willems, W.F.

    2014-01-01

    Reconstruction of avascular necrotic bone by pedicled bone grafting is a well-known treatment with little basic research supporting its application. A new canine model was used to simulate carpal bone avascular necrosis. Pedicled bone grafting proved to increase bone remodeling and bone blood flow,

  12. 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.

  13. [Thrombosis in vascular accesses for haemodialysis: rescue treatment using invasive vascular radiological techniques].

    Science.gov (United States)

    García Medina, J; Lacasa Pérez, N; Muray Cases, S; Pérez Garrido, I; García Medina, V

    2009-01-01

    The purpose of this paper is to communicate our experience in the salvage of thrombosed haemodialysis vascular accesses using interventional radiology techniques. In the last four years, we have treated, by radiological means, 101 thrombosed haemodialysis vascular accesses. There were 44 autologous arteriovenous fistulas (43.56%) and 57 PTFE grafts (56.44%). There were 69 men (68.3%) and 32 women (31.7%). The mean age was 67.73 years (range 33-84). The mean vascular access age was 23.79 months (range 1-132). Manual catheter-directed aspiration was used. Fragmented, triturated or pushed the thrombus against the pulmonary circulation was avoided in all cases. 78 accesses were salvaged (77.2%). Autologous fistulas average and PTFE grafts success rate were 84.44% and 71.42% respectively. Angioplasty in one or more lesions after thromboaspiration was performed in all accesses, except six (5.9%). Metallic endoprostheses were implanted in 14 accesses (13.9%). Mean follow-up was 9 months (range 0-44). Primary patency was 42.3% +/- 5 at 6 months and 32% +/- 4 at one year. Autologous fistulas patency was better than PTFE grafts patency (p better than PTFE grafts. This justifies interventional radiology techniques in these situations.

  14. Assessment of the viability of skin grafts

    International Nuclear Information System (INIS)

    Wahner, H.W.

    1988-01-01

    A number of tests are available to monitor the blood flow in free and distant pedicle skin grafts. The information from these tests aids in the development of measures to enhance vascularization and is occasionally needed to make clinical decisions in patients with distant pedicle grafts. Measurements of the disappearance of an intradermally injected small amount of 133 Xe allows determination of a clearance rate and blood flow before and after clamping the original blood supply through the base. With /sup 99m/Tc, which is generally more readily available, a flow index and block index can be determined. Clinically both procedures give equally good results in determining a safe time for pedicle base separation. The fluorescein test allows assessment of regional blood flow distribution within the pedicle

  15. 500-Gray γ-Irradiation May Increase Adhesion Strength of Lyophilized Cadaveric Split-Thickness Skin Graft to Wound Bed.

    Science.gov (United States)

    Wei, Lin-Gwei; Chen, Chieh-Feng; Wang, Chi-Hsien; Cheng, Ya-Chen; Li, Chun-Chang; Chiu, Wen-Kuan; Wang, Hsian-Jenn

    2017-03-01

    Human cadaveric skin grafts are considered as the "gold standard" for temporary wound coverage because they provide a more conductive environment for natural wound healing. Lyophilization, packing, and terminal sterilization with gamma-ray can facilitate the application of cadaveric split-thickness skin grafts, but may alter the adhesion properties of the grafts. In a pilot study, we found that 500 Gy γ-irradiation seemed not to reduce the adherence between the grafts and wound beds. We conducted this experiment to compare the adherences of lyophilized, 500-Gy γ-irradiated skin grafts to that of lyophilized, nonirradiated grafts. Pairs of wounds were created over the backs of Sprague- Dawley rats. Pairs of "lyophilized, 500-Gy γ-irradiated" and "lyophilized, nonirradiated" cadaveric split-thickness skin grafts were fixed to the wound beds. Adhesion strength between the grafts and the wound beds was measured and compared. On post-skin-graft day 7 and day 10, the adhesion strength of γ-irradiated grafts was greater than that of the nonirradiated grafts. Because lyophilized cadaveric skin grafts can be vascularized and the collagen of its dermal component can be remodeled after grafting, the superior adhesion strength of 500-Gy γ-irradiated grafts can be explained by the collagen changes from irradiation.

  16. Systemic thioridazine in combination with dicloxacillin against early aortic graft infections caused by Staphylococcus aureus in a porcine model

    DEFF Research Database (Denmark)

    Stenger, Michael; Behr-Rasmussen, Carsten; Klein, Kasper

    2017-01-01

    INTRODUCTION: Conservative treatment solutions against aortic prosthetic vascular graft infection (APVGI) for inoperable patients are limited. The combination of antibiotics with antibacterial helper compounds, such as the neuroleptic drug thioridazine (TDZ), should be explored. AIM: To investigate...

  17. [Value of preserved saphenous vein graft for the creation of access ports in hemodialyzed patients: report of 309 cases].

    Science.gov (United States)

    Schneider, Marc; Barrou, Benoît; Cluzel, Philippe; Hamani, Aziz; Bitker, Marc-Olivier; Richard, François

    2003-09-01

    Biological grafts are rarely used for the creation of vascular access, despite their many advantages. Our group prefers to use distal vascular accesses with interposition of a biological graft when direct access cannot be achieved. The objective of this study was to determine the long-term patency and the complication rate of a series of 309 vascular access procedures using a preserved saphenous (PS) vein homograft. 410 (27%) of the 1,500 vascular access procedures performed by our group required the use of a graft, including 376 PS vein homografts (25%). This retrospective study comprised complete data collection for 309 arteriovenous fistulas (AVF) using preserved saphenous (PS) vein graft in the forearm performed in 267 patients between 1985 and 2000. Primary patency was defined as the interval between creation of the vascular access and the first complication requiring surgical or radiological correction; secondary patency was defined as the interval between creation and loss of the graft, with or without revision of the fistula. Survival rates were calculated according to the Kaplan-Meier method. Inter-group comparison was performed by the Logrank test and analysis of variance was performed by logistic regression. Primary patency rates were 77%, 40% and 27% at 1,2 and 5 years, respectively. Secondary patency rates were 79% and 47% at 1 year and 5 years, respectively. The thrombosis rate was 42%. Two episodes of thrombosis occurred in 25% of grafts and 3 episodes were observed in 10% of cases. Infection rates were 1.9% postoperatively and 5% after dialysis, respectively. An aneurysm occurred on 10% of grafts. The operator's experience (RR = 1.58; p creation of vascular accesses with similar patency rates to those of prosthetic grafts. Vein grafts present a number of advantages, particularly a greater ease of use facilitating distal implantation of the graft and a low infection rate.

  18. 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.

  19. New options for vascularized bone reconstruction in the upper extremity.

    Science.gov (United States)

    Houdek, Matthew T; Wagner, Eric R; Wyles, Cody C; Nanos, George P; Moran, Steven L

    2015-02-01

    Originally described in the 1970s, vascularized bone grafting has become a critical component in the treatment of bony defects and non-unions. Although well established in the lower extremity, recent years have seen many novel techniques described to treat a variety of challenging upper extremity pathologies. Here the authors review the use of different techniques of vascularized bone grafts for the upper extremity bone pathologies. The vascularized fibula remains the gold standard for the treatment of large bone defects of the humerus and forearm, while also playing a role in carpal reconstruction; however, two other important options for larger defects include the vascularized scapula graft and the Capanna technique. Smaller upper extremity bone defects and non-unions can be treated with the medial femoral condyle (MFC) free flap or a vascularized rib transfer. In carpal non-unions, both pedicled distal radius flaps and free MFC flaps are viable options. Finally, in skeletally immature patients, vascularized fibular head epiphyseal transfer can provide growth potential in addition to skeletal reconstruction.

  20. 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

  1. 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.

  2. Surveillance Duplex Ultrasonography of Stent Grafts for Popliteal Aneurysms.

    Science.gov (United States)

    Pineda, Danielle M; Troutman, Douglas A; Dougherty, Matthew J; Calligaro, Keith D

    2016-05-01

    Stent grafts, also known as covered stents, have become an increasingly acceptable treatment for popliteal artery aneurysms. However, endovascular exclusion confers lower primary patency compared to traditional open bypass and exclusion. The purpose of this study was to evaluate whether duplex ultrasonography (DU) can reliably diagnose failing stent grafts placed for popliteal artery aneurysms prior to occlusion. Between June 5, 2007, and March 11, 2014, 21 stent grafts (Viabahn; Gore, Flagstaff, Arizona) were placed in 19 patients for popliteal artery aneurysms. All patients had at least 1 follow-up duplex scan postoperatively. Mean follow-up was 28.9 months (9-93 months). Postoperative DU surveillance was performed in our Intersocietal Accreditation Commission noninvasive vascular laboratory at 1 week postprocedure and every 6 months thereafter. Duplex ultrasonography measured peak systolic velocities (PSVs) and ratio of adjacent PSVs (Vr) every 5 cm within the stent graft and adjacent arteries. We retrospectively classified the following factors as "abnormal DU findings": focal PSV > 300 cm/s, uniform PSVs 3.0. These DU criteria were derived from laboratory-specific data that we previously published on failing stent grafts placed for lower extremity occlusive disease. Four of the 21 stent grafts presented with symptomatic graft thrombosis within 6 months of a normal DU. Three of these 4 patients presented with rest pain and underwent thrombectomy (2) or vein bypass (1), and 1 elected for nonintervention for claudication. Our results suggest that surveillance DU using criteria established for grafts placed for occlusive disease may not be useful for predicting stent graft failure in popliteal artery aneurysms. © The Author(s) 2016.

  3. [Allogeneic vascularized transplantation in cases of bone and joint defects].

    Science.gov (United States)

    Hofmann, G O; Kirschner, M H; Gonschorek, O; Bühren, V

    1999-06-01

    This paper presents preliminary results of allogeneic vascularized transplantations of three femoral diaphyses and four total human knee joints. Grafts were harvested from multi-organ-donors and immediately transplanted. Osteosyntheses were performed employing intramedullary nails. Vascular pedicles of the grafts were anastomosed in end-to-side technique. Immunosuppression mainly based on Cyclosporine and Azathioprine. Grafts' perfusion was demonstrated by DSA and Duplex-sonograms, bone metabolism by SPECT-scintigraphy. Five months following transplantation osteotomies demonstrated consolidation in conventional X-rays. Biopsies of the grafted bone revealed intact osteocytes and arthroscopy demonstrated intact synovial, chondral and ligamentous structures. From the technical aspect vascularized transplantation of the femoral diaphyses and total knee joints is feasible. The main problems are of immunologic nature. Transplantations were performed respecting the ABO-compatibility but with a large HLA-mismatch. Acute and chronic rejection crises may damage the grafts. At least in synovial joints live-long immunosuppression of the recipients seems to be unavoidable.

  4. One Year Outcomes of 101 BeGraft Stent Grafts used as Bridging Stents in Fenestrated Endovascular Repairs.

    Science.gov (United States)

    Spear, Rafaelle; Sobocinski, Jonathan; Hertault, Adrien; Delloye, Matthieu; Azzauiu, Richard; Fabre, Dominique; Haulon, Stéphan

    2018-04-01

    To evaluate the outcomes of the second generation BeGraft balloon expandable covered stent Graft System (Bentley InnoMed, Hechingen, Germany) implanted as bridging stent grafts during fenestrated endovascular aortic repair (FEVAR) of complex aneurysms. This was a single centre prospective study including all consecutive patients treated by FEVAR performed with second generation BeGraft stent grafts as bridging stents. Demographics of patients, diameter and length of the bridging stent grafts, technical success, re-interventions, occlusions, post-operative events, and imaging (Cone Beam CT and/or CT scan, and contrast enhanced ultrasound) were prospectively collected in an electronic database. Duplex ultrasound was performed before discharge and at 6 month follow-up. At 1 year, patients were evaluated clinically and by imaging (CT and ultrasound). Between November 2015 and September 2016, 39 consecutive patients (one woman) were treated with custom made fenestrated endografts (2-5 fenestrations) for complex aneurysms or type 1 endoleak after EVAR, using a variety of bridging stents including the BeGraft. All 101 BeGraft stent grafts were successfully delivered and deployed. There was no in hospital mortality. Early fenestration patency rate was 99% (96/97); the sole target vessel post-operative occlusion was secondary to a dissection of the renal artery distal to the stent. Complementary stenting was unsuccessful in recovering renal artery patency; bilateral renal stent occlusion was observed in the same patient on a CT scan performed 2 months after the procedure. He required post-operative dialysis. No additional renal impairment was observed. During follow-up (median 13 months [11-15]), all fenestrations stented with BeGraft stent grafts remained patent (95/97, 98%). One type 1b endoleak was detected and treated (2.6%). BeGraft stent grafts used as bridging stents during FEVAR are associated with favourable outcomes at 1 year follow-up. Long-term follow-up is

  5. 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.

  6. The use of bovine pericardial patch for vascular reconstruction in infected fields for transplant recipients

    Directory of Open Access Journals (Sweden)

    Sandra Garcia Aroz, MD

    2017-03-01

    Full Text Available Infectious vascular complications affecting transplant recipients may lead to severe morbidity and graft loss. This is a retrospective review of vascular repair with bovine pericardial patch (BPP in infected fields for immunosuppressed patients. BPP was used as either a patch or an interposition graft. Five cases of arterial reconstruction in infected fields using BPP were performed. There were no complications related to bleeding, thrombosis, or recurrent infection. In our limited experience, the use of BPP as a vascular patch is successful, and it represents an alternative when vascular reconstruction is needed in the context of infected fields.

  7. [Immunologic problems in vascular homografts].

    Science.gov (United States)

    D'Addato, M; Mirelli, M

    2001-01-01

    Fresh arterial homografts are immunogenic, inducing in recipient a strong immune response specifically directed against the antigens of the donor graft. The initial immune response seems to be cellular (lymphocytotoxic) and the late reaction humoral (antibody), even if they are strictly correlated. Immunosuppressive therapy reduce the immune reaction, but this response is dose-related. Implanted arterial homografts induce a donor-specific response similar to chronic reaction, which occurs in the recipients of vascularized solid-organ allografts. Therefore, in arterial transplantation, ABO compatibility and negative crossmatch should be respected. Effort should be made to curb the immune response by prospective cross-matching, immunosuppressive therapy and preoperative manipulation of homografts to reduce their antigenicity.

  8. Graft-Sparing Strategy for Thoracic Prosthetic Graft Infection.

    Science.gov (United States)

    Uchino, Gaku; Yoshida, Takeshi; Kakii, Bunpachi; Furui, Masato

    2018-04-01

     Thoracic prosthetic graft infection is a rare but serious complication with no standard management. We reported our surgical experience on graft-sparing strategy for thoracic prosthetic graft infection.  This study included patients who underwent graft-sparing surgery for thoracic prosthetic graft infection at Matsubara Tokushukai Hospital in Japan from January 2000 to October 2017.  There were 17 patients included in the analyses, with a mean age at surgery of 71.0 ± 10.5 years; 11 were men. In-hospital mortality was observed in five patients (29.4%).  Graft-sparing surgery for thoracic prosthetic graft infection is an alternative option particularly for early graft infection after hemiarch replacement. Georg Thieme Verlag KG Stuttgart · New York.

  9. Multidetector-Row Computed Tomography in the Evaluation of Transjugular Intrahepatic Portosystemic Shunt Performed with Expanded-Polytetrafluoroethylene-Covered Stent-Graft

    International Nuclear Information System (INIS)

    Fanelli, Fabrizio; Bezzi, Mario; Bruni, Antonio; Corona, Mario; Boatta, Emanuele; Lucatelli, Pierleone; Passariello, Roberto

    2011-01-01

    We assessed, in a prospective study, the efficacy of multidetector spiral computed tomography (MDCT) in the evaluation of transjugular intrahepatic portosystemic shunt (TIPS) patency in patients treated with the Viatorr (Gore, Flagstaff, AZ) expanded-polytetrafluoroethylene (e-PTFE)-covered stent-graft. Eighty patients who underwent TIPS procedure using the Viatorr self-expanding e-PTFE stent-graft were evaluated at follow-up of 1, 3, 6, and 12 months with clinical and laboratory tests as well as ultrasound–color Doppler (USCD) imaging. In case of varices, upper gastrointestinal endoscopy was also performed. In addition, the shunt was evaluated using MDCT at 6 and 12 months. In all cases of abnormal findings and discrepancy between MDCT and USCD, invasive control venography was performed. MDCT images were acquired before and after injection of intravenous contrast media on the axial plane and after three-dimensional reconstruction using different algorithms. MDCT was successfully performed in all patients. No artefacts correlated to the Viatorr stent-graft were observed. A missing correlation between UCSD and MDCT was noticed in 20 of 80 (25%) patients. Invasive control venography confirmed shunt patency in 16 (80%) cases and shunt malfunction in 4 (20%) cases. According to these data, MDCT sensitivity was 95.2%; specificity was 96.6%; and positive (PPV) and negative predictive values (NPV) were 90.9 and 98.2%, respectively. USCD sensitivity was 90%; specificity was 75%; and PPV and NPV were 54.5 and 95.7%, respectively. A high correlation (K value = 0.85) between MDCT and invasive control venography was observed. On the basis of these results, MDCT shows superior sensitivity and specificity compared with USCD in those patients in whom TIPS was performed with the Viatorr stent-graft. MDCT can be considered a valid tool in the follow-up of these patients.

  10. 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.

  11. Prostanoids modulate inflammation and alloimmune responses during graft rejection

    Directory of Open Access Journals (Sweden)

    P.N. Rocha

    2005-12-01

    Full Text Available Acute rejection of a transplanted organ is characterized by intense inflammation within the graft. Yet, for many years transplant researchers have overlooked the role of classic mediators of inflammation such as prostaglandins and thromboxane (prostanoids in alloimmune responses. It has been demonstrated that local production of prostanoids within the allograft is increased during an episode of acute rejection and that these molecules are able to interfere with graft function by modulating vascular tone, capillary permeability, and platelet aggregation. Experimental data also suggest that prostanoids may participate in alloimmune responses by directly modulating T lymphocyte and antigen-presenting cell function. In the present paper, we provide a brief overview of the alloimmune response, of prostanoid biology, and discuss the available evidence for the role of prostaglandin E2 and thromboxane A2 in graft rejection.

  12. Bioprinting for vascular and vascularized tissue biofabrication.

    Science.gov (United States)

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

    2017-03-15

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

  13. 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

  14. 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

  15. Primary renal graft thrombosis

    NARCIS (Netherlands)

    Bakir, N; Sluiter, WJ; Ploeg, RJ; van Son, WJ; Tegzess, Adam

    Background. Renal allograft thrombosis is a serious complication of kidney transplantation that ultimately leads to graft loss. Its association with acute and hyperacute rejection is well documented; however, in a large proportion of patients the precise cause remains obscure. The exact incidence

  16. 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.

  17. 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.

  18. Rapamycin treatment is associated with an increased apoptosis rate in experimental vein grafts.

    Science.gov (United States)

    Schachner, Thomas; Oberhuber, Alexander; Zou, Yping; Tzankov, Alexandar; Ott, Harald; Laufer, Günther; Bonatti, Johannes

    2005-02-01

    Rapamycin is an immunosuppressive agent with marked antiproliferative properties and is effective in reducing in stent restenosis and vein graft neointimal hyperplasia. Apoptosis is one mechanism counterbalancing cellular proliferation. We therefore investigated the role of apoptosis in rapamycin treated vein grafts in a mouse model. C57BL6J mice underwent interposition of the inferior vena cava from isogenic donor mice into the common carotid artery using a cuff technique. In the treatment group 200 microg of rapamycin were applied locally in pluronic gel. The control group did not receive local treatment. Vein grafts were harvested at 4 weeks postoperatively and underwent morphometric analysis as well as immunohistochemical analysis for apoptosis (TUNEL). In grafted veins without treatment (controls) neointimal thickness was 50 (12-58) microm at 4 weeks postoperatively. In 200 microg rapamycin treated grafts the neointimal thickness was 17 (5-55) microm. Rapamycin treated vein grafts showed a significantly increased rate of apoptosis in the adventitia as compared with controls (P=0.032). In the neointima the apoptosis rate was lower in both groups with no significant difference between rapamycin treated grafts and controls. We conclude that treatment of experimental vein grafts with rapamycin is associated with an increased apoptosis rate in the vascular wall and a trend towards reduction of neointimal hyperplasia. These results suggest that apoptosis may be a beneficial antiproliferative component for the treatment of vein graft disease.

  19. 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.

  20. 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)

  1. 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.

  2. 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.

  3. Configuration affects parallel stent grafting results.

    Science.gov (United States)

    Tanious, Adam; Wooster, Mathew; Armstrong, Paul A; Zwiebel, Bruce; Grundy, Shane; Back, Martin R; Shames, Murray L

    2018-05-01

    .25% of retrograde stents having any complication. Parallel stent grafting offers an off-the-shelf option to treat a variety of aortic diseases. There is an increased risk of parallel stent and overall EVAR compromise with stent is placed. Antegrade configurations are preferred to any retrograde configuration, with optimal oversizing >20%. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  4. The effect of infection and lag screw fixation on revascularization and new bone deposition in membranous bone grafts in a rabbit model.

    Science.gov (United States)

    Fialkov, J A; Phillips, J H; Walmsley, S L; Morava-Protzner, I

    1996-08-01

    We have suggested that rigid fixation of membranous bone grafts in the presence of infection may improve graft-recipient bone union by facilitating graft revascularzation. To test this hypothesis, we grafted autogenous membranous bone grafts to the mandibles of 94 New Zealand White rabbits. Lag screw fixation was applied in half the animals. The wounds were inoculated with a range of Staphylococcus aureus doses. Infected and noninfected rabbits were injected weekly over a 5-week course with fluorescein bone markers and with a marker of vascular endothelium (procion red) just prior to sacrifice. Revascularization and new bone deposition in the grafts were then quantified histologically for the 75 rabbits available for data collection. Infection decreased the amount of graft revascularized and the amount of new bone deposited for both rigidly fixated and nonfixated grafts. Grafts fixated with a lag screw showed a greater amount of revascularization and new bone deposition in the presence and absence of infection when compared with nonfixated grafts, supporting the hypothesis that rigid fixation of membranous bone grafts in the presence of infection may promote graft survival and union by improving revascularization and osteogenesis within the graft.

  5. 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.

  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. 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.

  8. 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)

  9. Effect of external volume expansion on the survival of fat grafts

    Directory of Open Access Journals (Sweden)

    Raghuveer Reddy

    2016-01-01

    Full Text Available Introduction: External volume expansion (EVE is one method, which has been utilised for increasing the survival of adipose tissue grafts. EVE releases positive pressure from the graft and also induces intense levels of edema that decreases diffusion of metabolites essential for graft survival initially. The ideal timing of external volume expansion in relation to the injection of the fat to facilitate survival is not yet clear. Aims and Objectives: This study was undertaken to evaluate and compare the efficacy of external volume expansion applied at variable time points in relation to the injection of the fat. Materials and Methods: Athymic mouse was the animal model and human lipo-aspirate mixed with PRP was used as graft. An indigenous dome shaped silicone device was fabricated to deliver a negative pressure of -30 mm of Hg. The EVE was applied at variable time intervals. At the end of 4 weeks visual, histological and radiological features of the injected fat were compared. The adipose tissue was stained with human vimentin to ascertain the origin of the retained fat. Results: All the grafts, which had EVE, had significantly better volume retention and vascularity. The groups which underwent a delayed EVE or prior expansion followed by concomitant graft injection and expansion showed the most optimal vascularity and graft retention. Conclusions: A delayed EVE or prior expansion followed by concomitant graft injection and expansion may be the most ideal combinations to optimize graft take. However, on account of the relatively small sample size, there was a limitation in drawing statistically significant conclusions for certain variables.

  10. Effect, Feasibility, and Clinical Relevance of Cell Enrichment in Large Volume Fat Grafting: A Systematic Review.

    Science.gov (United States)

    Rasmussen, Bo Sonnich; Lykke Sørensen, Celine; Vester-Glowinski, Peter Viktor; Herly, Mikkel; Trojahn Kølle, Stig-Frederik; Fischer-Nielsen, Anne; Drzewiecki, Krzysztof Tadeusz

    2017-07-01

    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 grafting. Improvements in graft retention, the SVF to fat (SVF:fat) ratio, and the ASC concentration used for enrichment were emphasized. We proposed an increased retention rate greater than 1.5-fold relative to nonenriched grafts and a maximum SVF:fat ratio of 1:1 as the thresholds for clinical relevance and feasibility, respectively. Nine studies fulfilled these criteria, whereof 6 used ASCs for enrichment. We found no convincing evidence of a clinically relevant effect of SVF enrichment in humans. ASC enrichment has shown promising results in enhancing graft retention, but additional clinical trials are needed to substantiate this claim and also determine the optimal concentration of SVF cells/ASCs for enrichment. 4. © 2017 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

  11. 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.

  12. Grafting the alar rim: application as anatomical graft.

    Science.gov (United States)

    Gruber, Ronald P; Fox, Paige; Peled, Anne; Belek, Kyle A

    2014-12-01

    Alar rim contour and alar rim grafts have become essential components of rhinoplasty. Ideally, grafts of the nose should be anatomical in shape. So doing might make grafts of the alar rim more robust. The authors considered doing that by applying the graft as a continuous extension of the lateral crus. Twelve patients (two men and 10 women) constituted the study group (seven primary and five secondary cases). Of those, there were five concave rims, two concave rims with rim retraction, two boxy tips, and three cephalically oriented lateral crura. Surgical technique included the following: (1) an open approach was used; (2) a marginal incision that ignored the caudal margin of the lateral crus (the incision went straight posteriorly to a point 5 to 6 mm from the rim margin) was used; (3) a triangular graft was made to cover the exposed vestibular skin; (4) it was secured end to end to the caudal border of the lateral crus; and (5) the poster end was allowed to sit in a small subcutaneous pocket. Follow-up was 11 to 19 months. All 12 patients exhibited good rims as judged by a blinded panel. Rim retraction was not fully corrected in one patient, but no further treatment was required. One patient did require a secondary small rim graft for residual rim concavity. The concept of grafting the alar rim is strongly supported by the authors' results. The modifications the authors applied by designing the graft to be anatomical in shape has been a technical help.

  13. 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.

  14. The Use of Grafting to Study Systemic Signaling in Plants.

    Science.gov (United States)

    Tsutsui, Hiroki; Notaguchi, Michitaka

    2017-08-01

    Grafting has long been an important technique in agriculture. Nowadays, grafting is a widely used technique also to study systemic long-distance signaling in plants. Plants respond to their surrounding environment, and at that time many aspects of their physiology are regulated systemically; these start from local input signals and are followed by the transmission of information to the rest of the plant. For example, soil nutrient conditions, light/photoperiod, and biotic and abiotic stresses affect plants heterogeneously, and plants perceive such information in specific plant tissues or organs. Such environmental cues are crucial determinants of plant growth and development, and plants drastically change their morphology and physiology to adapt to various events in their life. Hitherto, intensive studies have been conducted to understand systemic signaling in plants, and grafting techniques have permitted advances in this field. The breakthrough technique of micrografting in Arabidopsis thaliana was established in 2002 and led to the development of molecular genetic tools in this field. Thereafter, various phenomena of systemic signaling have been identified at the molecular level, including nutrient fixation, flowering, circadian clock and defense against pathogens. The significance of grafting is that it can clarify the transmission of the stimulus and molecules. At present, many micro- and macromolecules have been identified as mobile signals, which are transported through plant vascular tissues to co-ordinate their physiology and development. In this review, we introduce the various grafting techniques that have been developed, we report on the recent advances in the field of plant systemic signaling where grafting techniques have been applied and provide insights for the future. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  15. 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.

  16. Magnetizable stent-grafts enable endothelial cell capture

    Science.gov (United States)

    Tefft, Brandon J.; Uthamaraj, Susheil; Harburn, J. Jonathan; Hlinomaz, Ota; Lerman, Amir; Dragomir-Daescu, Dan; Sandhu, Gurpreet S.

    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.

  17. 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)

  18. SOME TECHNIQUES IN CORNEAL GRAFTING

    African Journals Online (AJOL)

    1971-04-10

    Apr 10, 1971 ... current herpes corneae. The visual acuity was less than. 6/60. The left eye had had a central nebula since child- hood and was deemed amblyopic. Six weeks after a 7 x 0·3 mm lamellar graft in the right eye was placed, ulceration occurred in the graft junction. A total thin conjunctival flap was sutured over.

  19. Polyether/Polyester Graft Copolymers

    Science.gov (United States)

    Bell, Vernon L., Jr.; Wakelyn, N.; Stoakley, D. M.; Proctor, K. M.

    1986-01-01

    Higher solvent resistance achieved along with lower melting temperature. New technique provides method of preparing copolymers with polypivalolactone segments grafted onto poly (2,6-dimethyl-phenylene oxide) backbone. Process makes strong materials with improved solvent resistance and crystalline, thermally-reversible crosslinks. Resulting graft copolymers easier to fabricate into useful articles, including thin films, sheets, fibers, foams, laminates, and moldings.

  20. 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

  1. Disruptive technological advances in vascular access for dialysis: an overview.

    Science.gov (United States)

    Yeo, Wee-Song; Ng, Qin Xiang

    2017-11-29

    End-stage kidney disease (ESKD), one of the most prevalent diseases in the world and with increasing incidence, is associated with significant morbidity and mortality. Current available modes of renal replacement therapy (RRT) include dialysis and renal transplantation. Though renal transplantation is the preferred and ideal mode of RRT, this modality may not be available to all patients with ESKD. Moreover, renal transplant recipients are constantly at risk of complications associated with immunosuppression and immunosuppressant use, and posttransplant lymphoproliferative disorder. Dialysis may be the only available modality in certain patients. However, dialysis has its limitations, which include issues associated with lack of vascular access, risks of infections and vascular thrombosis, decreased quality of life, and absence of biosynthetic functions of the kidney. In particular, the creation and maintenance of hemodialysis vascular access in children poses a unique set of challenges to the pediatric nephrologist owing to the smaller vessel diameters and vascular hyperreactivity compared with adult patients. Vascular access issues continue to be one of the major limiting factors prohibiting the delivery of adequate dialysis in ESKD patients and is the Achilles' heel of hemodialysis. This review aims to provide a critical overview of disruptive technological advances and innovations for vascular access. Novel strategies in preventing neointimal hyperplasia, novel bioengineered products, grafts and devices for vascular access will be discussed. The potential impact of these solutions on improving the morbidity encountered by dialysis patients will also be examined.

  2. Late graft explants in endovascular aneurysm repair.

    Science.gov (United States)

    Turney, Eric J; Steenberge, Sean P; Lyden, Sean P; Eagleton, Matthew J; Srivastava, Sunita D; Sarac, Timur P; Kelso, Rebecca L; Clair, Daniel G

    2014-04-01

    With more than a decade of use of endovascular aneurysm repair (EVAR), we expect to see a rise in the number of failing endografts. We review a single-center experience with EVAR explants to identify patterns of presentation and understand operative outcomes that may alter clinical management. A retrospective analysis of EVARs requiring late explants, >1 month after implant, was performed. Patient demographics, type of graft, duration of implant, reason for removal, operative technique, length of stay, complications, and in-hospital and late mortality were reviewed. During 1999 to 2012, 100 patients (91% men) required EVAR explant, of which 61 were placed at another institution. The average age was 75 years (range, 50-93 years). The median length of time since implantation was 41 months (range, 1-144 months). Explanted grafts included 25 AneuRx (Medtronic, Minneapolis, Minn), 25 Excluder (W. L. Gore & Associates, Flagstaff, Ariz), 17 Zenith (Cook Medical, Bloomington, Ind), 15 Talent (Medtronic), 10 Ancure (Guidant, Indianapolis, Ind), 4 Powerlink (Endologix, Irvine, Calif), 1 Endurant (Medtronic), 1 Quantum LP (Cordis, Miami Lakes, Fla), 1 Aorta Uni Iliac Rupture Graft (Cook Medical, Bloomington, Ind), and 1 homemade tube graft. Overall 30-day mortality was 17%, with an elective case mortality of 9.9%, nonelective case mortality of 37%, and 56% mortality for ruptures. Endoleak was the most common indication for explant, with one or more endoleaks present in 82% (type I, 40%; II, 30%; III, 22%; endotension, 6%; multiple, 16%). Other reasons for explant included infection (13%), acute thrombosis (4%), and claudication (1%). In the first 12 months, 23 patients required explants, with type I endoleak (48%) and infection (35%) the most frequent indication. Conversely, 22 patients required explants after 5 years, with type I (36%) and type III (32%) endoleak responsible for most indications. The rate of EVAR late explants has increased during the past decade at our

  3. Uptake of radiolabeled leukocytes in prosthetic graft infection

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. Experience of vascular trauma in a tertiary care hospital

    International Nuclear Information System (INIS)

    Imtiaz, N.

    2010-01-01

    To highlight the presentation and management of various vascular injuries and their outcome. Thirty nine cases of vascular trauma were referred to vascular surgeon CMH Rawalpindi, in the above mentioned period. These cases were evaluated for mechanism of injury, age, gender and time of presentation. Out of these, only thirty cases were found suitable for surgical intervention. These thirty cases were evaluated for site of vascular injury, associated injuries, type of surgery performed and the outcome. Blunt trauma was the predominant cause of vascular injuries in our study 16/39 (41%). Fourteen cases (35.8%) had gun shot wounds. Only thirty patients (76.9 %) underwent various surgical procedures. Primary end to end anastomosis was possible in only 5/30 cases (16.6%) while reversed venous graft was used in 13/30 cases (43.3%). Wound infection occurred in 2/30(6.6%) cases out of which 1 case (3.3%) ultimately had an amputation. The time period between injury and surgical intervention ranged between 1 to 20 hours for most of the vascular injuries while delayed presentation in the form of traumatic arteriovenous fistula or pseudoaneurysm was between 48 hours to 3 months. There are reasonable numbers of vascular trauma cases being referred to a tertiary care hospital. Most of these cases reach us quite late due to unnecessary investigations, delayed referral and transportation. Early intervention and revascularization definitely reduces amputation and complication rate. All gunshot wounds not only require thorough surrounding soft tissue debridement but also liberal excision of traumatised vessel itself, resulting in interposition graft repair. (author)

  9. Renographic indices for evaluation of changes in graft function

    Energy Technology Data Exchange (ETDEWEB)

    El-Maghraby, T.A.F.; Eck-Smit, B.L.F. van; Pauwels, E.K.J. [Division of Nuclear Medicine, Department of Radiology, Leiden University Medical Centre, Leiden (Netherlands); Fijter, J.W. de [Department of Nephrology, Leiden University Medical Centre, Leiden (Netherlands); Zwinderman, A.H. [Department of Medical Statistics, Leiden University Medical Centre, Leiden (Netherlands); El-Haddad, S.I. [Department of Oncology and Nuclear Medicine, Cairo University (Egypt)

    1998-11-01

    Radionuclide renal diagnostic studies play an important role in assessing renal allograft function, especially in the early post-transplant period. In the past two decades various quantitative parameters have been derived from the radionuclide renogram to evaluate changes in perfusion and/or function of the kidney allograft. In this review article we discuss the quantitative parameters that have been used to assess graft condition, with emphasis on the early postoperative period. These quantitative methods are divided into parameters used for assessing renal graft perfusion and parameters used for evaluating parenchymal function. The blood flow in renal transplants can be quantified (a) by measuring the rate of activity appearance in the kidney graft, (b) by calculating the ratio of the integral activity under the transplanted kidney and arterial curves and (c) by calculating the renal vascular transit time. In this article we review a number of parenchymal uptake and excretion indices, such as the accumulation index, the graft uptake capacity at 2 and 10 min, the excretion index and the elimination index. The literature on these parameters shows that they have some practical disadvantages. In addition, values suffer from significant overlap when various graft pathologies coexist. A retrospective study was designed in our institution to evaluate the clinical usefulness of some of the frequently used previously published methods in which the graft function is quantitatively assessed in the early post-transplant period. The quantitative parameters studied which were reasonably reproducible in our hands included: global perfusion index (GPI), cortical perfusion index (CPI), vascular transit time, and the parenchymal parameters uptake capacity at 2 min (UC{sub 2}) and elimination index (K{sub 3/20}). The patient population in this study consisted of 43 patients with 157 technetium-99m mercaptylacetyltriglycine renograms. The perfusion indices GPI and CPI did not allow

  10. Cytocompatibility of polyethylene grafted with triethylenetetramine functionalized carbon nanoparticles

    Science.gov (United States)

    Žáková, Pavlína; Slepičková Kasálková, Nikola; Slepička, Petr; Kolská, Zdeňka; Karpíšková, Jana; Stibor, Ivan; Švorčík, Václav

    2017-11-01

    Various carbon nanostructures are widely researched as scaffolds for tissue engineering. We evaluated the surface properties and cell-substrate interactions of carbon nanoparticles functionalized with triethylenetetramine (CNPs) grafted polymer film. Two forms of polyethylene (HDPE, LDPE) were treated in an inert argon plasma discharge and, subsequently, grafted with CNPs. The surface properties were studied using multiple methods, including Raman spectroscopy, goniometry, atomic force microscopy, X-ray photoelectron spectroscopy and electrokinetic analysis. Cell-substrate interactions were determined in vitro by studying adhesion, proliferation and viability of vascular smooth muscle cells (VSMCs) from the aorta of a rat. Cell-substrate interactions on pristine and modified substrates were compared to standard tissue culture polystyrene. Our results show that CNPs affect surface morphology and wettability and therefore adhesion, proliferation and viability of cultured muscle cells.

  11. 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...... years and 4 months. The microvessels were immunohistochemically stained by antibodies against CD34. Angiogenesis was graded semiquantitatively by subjective scoring into three groups according to the expected number of microvessels in the most vascular tumour area. The vascular grading between observers...... 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....

  12. 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...... years and 4 months. The microvessels were immunohistochemically stained by antibodies against CD34. Angiogenesis was graded semiquantitatively by subjective scoring into three groups according to the expected number of microvessels in the most vascular tumour area. The vascular grading between observers...... 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....

  13. 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.

  14. 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.

  15. Platelet-Rich Fibrin Improves the Viability of Diced Cartilage Grafts in a Rabbit Model.

    Science.gov (United States)

    Göral, Ali; Aslan, Cem; Bolat Küçükzeybek, Betül; Işık, Dağhan; Hoşnuter, Mübin; Durgun, Mustafa

    2016-04-01

    Diced cartilage may be wrapped with synthetic or biological materials before grafting to a recipient site. These materials have unique advantages and disadvantages, and a gold standard is not available. The authors investigated the effects of platelet-rich fibrin (PRF) on the survival of cartilage grafts in a rabbit model. In this experimental study, diced cartilage pieces from the ears of 9 male rabbits were left unwrapped or were wrapped with PRF, oxidized regenerated cellulose, or fascia. Specimens then were placed into subcutaneous pockets prepared on the backs of the rabbits. The animals were sacrificed 2 months after the procedure, and the grafts were excised for macroscopic and histopathologic examination. The cartilage graft wrapped with PRF showed superior viability compared with the cartilage graft wrapped with oxidized regenerated cellulose. No significant differences were found among the other groups. The groups were not significantly different in terms of rates of inflammation, fibrosis, or vascularization. PRF enhances the viability of diced cartilage grafts and should be considered an appropriate biological wrapping material for cartilage grafting. © 2016 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

  16. Cartilage grafting in nasal reconstruction.

    Science.gov (United States)

    Immerman, Sara; White, W Matthew; Constantinides, Minas

    2011-02-01

    Nasal reconstruction after resection for cutaneous malignancies poses a unique challenge to facial plastic surgeons. The nose, a unique 3-D structure, not only must remain functional but also be aesthetically pleasing to patients. A complete understanding of all the layers of the nose and knowledge of available cartilage grafting material is necessary. Autogenous material, namely septal, auricular, and costal cartilage, is the most favored material in a free cartilage graft or a composite cartilage graft. All types of material have advantages and disadvantages that should guide the most appropriate selection to maximize the functional and cosmetic outcomes for patients. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Inheritance of graft compatibility in Douglas fir.

    Science.gov (United States)

    D.L. Copes

    1973-01-01

    Graft compatibility of genetically related and unrelated rootstock-scion combinations was compared. Scion clones were 75% compatible when grafted on half-related rootstocks but only 56% compatible when grafted on unrelated rootstocks. Most variance associated with graft incompatibility in Douglas-fir appears to be caused by multiple genes.

  18. 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...

  19. 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.

  20. 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.

  1. 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.)

  2. The implantation of separating aortic stent-graft into the canine thoracic aorta: an experimental study

    International Nuclear Information System (INIS)

    Xia Jinguo; Shi Haibin; Yang Zhengqiang; Li Chao; Liu Sheng; Zu Qingquan; Li Linsun

    2011-01-01

    Objective: to assess the technical feasibility of implanting separating stent-graft into the canine thoracic aorta and to study its biocompatibility. Methods: Twelve adult dogs were randomly and equally divided into three groups. The right femoral artery was cut open, through which the separating stent-graft was inserted and deployed in the canine thoracic aorta, with the proximal end of the graft being quite close to the origin of the left subclavian artery. the technical feasibility of the deployment process was assessed. Angiography was performed at 4, 8 and 12 weeks after stent-graft placement to evaluate the position and patency of the stent-graft. Then the dogs were sacrificed and the specimens were collected for pathologic study. Both gross and microscopic examinations were made to evaluate the fixation of the stent-graft with the vessel wall, the endothelialization of stent-graft surface and the pathologic changes of the vascular wall. Results: A total of ten separating stent-grafts were successfully deployed in the canine thoracic aorta, no migration or deformation occurred. One dog died of massive bleeding due to the rupture of the right femoral artery which occurred when the delivery system containing the inner bare stent was inserted through the right femoral artery. Death occurred in another dog as a result of the ascending aorta rupture caused by the migration of outer-layer stent-graft. Angiography was conducted at 4, 8 and 12 weeks after stent-graft placement. No migration, deformation, rupture or stenosis of the implanted stent-grafts were observed. The formation of intima on the inner surface of the bare stent appeared at 4 weeks, which became more and more obvious with the time passing, and at 12 weeks complete endothelialization of stent-graft surface was observed. Conclusion: Technically, it is feasible to deploy the separating aortic stent-graft into the canine thoracic aorta. Moreover, the separating aortic stent-graft carries excellent

  3. Fat Grafting for Facial Filling and Regeneration.

    Science.gov (United States)

    Coleman, Sydney R; Katzel, Evan B

    2015-07-01

    Plastic surgeons have come to realize that fat grafting can rejuvenate an aging face by restoring or creating fullness. However, fat grafting does much more than simply add volume. Grafted fat can transform or repair the tissues into which it is placed. Historically, surgeons have hesitated to embrace the rejuvenating potential of fat grafting because of poor graft take, fat necrosis, and inconsistent outcomes. This article describes fat grafting techniques and practices to assist readers in successful harvesting, processing, and placement of fat for optimal graft retention and facial esthetic outcomes. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Design of a Sapling Branch Grafting Robot

    Directory of Open Access Journals (Sweden)

    Qun Sun

    2014-01-01

    Full Text Available The automatic sapling grafting methods and grafting robot technologies are not comprehensively studied despite the fact that they are urgently required in practice. For this reason, a sapling grafting robot is developed to implement automatic grafting for saplings. The developed grafting robot includes clipping mechanism, moving mechanism, cutting mechanism, binding mechanism, and Arduino MCU based control system, which is capable of clipping, moving, positioning, cutting, grafting, and binding saplings. Experiments show that the stock cutting efficiency is 98.4%, the scion cutting efficiency is 98.9%, the grafting efficiency is 87.3%, and the binding efficiency is 68.9%.

  5. 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

  6. A comparison of skin graft success in the head & neck with and without the use of a pressure dressing.

    Science.gov (United States)

    Dhillon, M; Carter, C P; Morrison, J; Hislop, W S; Currie, W J R

    2015-06-01

    The success of skin grafting is dependent on the interplay between many factors including nutrient uptake and vascular in-growth. To allow this, it is important that the graft is immobile and traditionally a 'pressure dressing' has been placed over the graft to improve outcome and graft 'take'. We present the findings of our comparative study of full-thickness skin grafts performed in the head, neck and face region over a period of 24 months. We felt that there was an unacceptably high infection rate and graft failure using pressure dressings. Data was collected retrospectively from the case notes on 70 patients who had undergone full-thickness skin grafting to the head, neck and face over a 2 year period. Thirty-five patients underwent grafting with pressure dressing and 35 without. The group with the pressure dressing had the same 'bolster' specification-type dressing and those without had their graft 'quilted' in and chloramphenicol ointment applied topically. Success was determined by the percentage 'take' of the grafts and absence of infection i.e. purulence. Infection in those with a pressure dressing stood at 26 % in contrast to those without, at 9 %. Without a pressure dressing we observed no total graft failures, compared to 6 % in those with a pressure dressing. The results confirmed the perception that there was a higher infection and graft failure rate where a pressure dressing was applied; however, this was not a statistically significant difference and a randomised control trial with a larger sample size would be required to validate the results.

  7. Hydrophilic/hydrophobic character of grafted cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Takacs, E., E-mail: takacs@iki.kfki.h [Institute of Isotopes, Hungarian Academy of Sciences, Budapest (Hungary); Wojnarovits, L. [Institute of Isotopes, Hungarian Academy of Sciences, Budapest (Hungary); Borsa, J. [Budapest University of Technology and Economics (Hungary); Racz, I. [Bay Zoltan Institute for Materials Science and Technology, Budapest (Hungary)

    2010-04-15

    Vinyl monomers with long paraffin chains were grafted onto two kinds of cellulose (cotton and cotton linter) by direct irradiation grafting technique. The effect of dose, monomer structure and concentration, as well as homopolymer suppressor (styrene) concentration on the grafting yield was studied and the optimal grafting conditions were established. Grafting decreased the swelling of the samples in water and increased their polymer compatibility in polypropylene matrix.

  8. 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

  9. The inferior medial genicular artery and its vascularization of the pes anserinus superficialis: A cadaveric study

    Directory of Open Access Journals (Sweden)

    Lena Hirtler

    2016-01-01

    Conclusion: Although intratendinous vascularization of the tendons of the PAS via the IMGA was not proven, this study indicates a new possibility of ACL reconstruction. The described operation technique can be conducive to shorten the vulnerable phase of the graft-ligamentization after ACL reconstruction.

  10. 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 unroll completely before floating against host stroma. An air pump-assisted technique using continuous pressurized air infusion allows successful final graft positioning even with very young donor corneas. It thus makes surgery easier as several key steps are made easier to handle. It additionally helps in tamponading hemorrhage during peripheral iridectomy, increasing surgical space, preventing fluctuations in the anterior chamber depth, and promoting graft adherence.

  11. FAS grafted superhydrophobic ceramic membrane

    Energy Technology Data Exchange (ETDEWEB)

    Lu Jun [School of Material Science and Engineering, Jingdezhen Ceramic Institute, 333001 Jingdezhen (China); Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, CAS, 1295 DingXi Road, Shanghai 200050 (China); Yu Yun, E-mail: yunyush@mail.sic.ac.cn [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, CAS, 1295 DingXi Road, Shanghai 200050 (China); Zhou Jianer [School of Material Science and Engineering, Jingdezhen Ceramic Institute, 333001 Jingdezhen (China); Song Lixin; Hu Xingfang [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, CAS, 1295 DingXi Road, Shanghai 200050 (China); Larbot, Andre [Institut Europeen des Membranes, UMR 5635-CNRS, ENSCM, UMII, 1919 Route de Mende 34293, Montpellier Cedex 5 (France)

    2009-08-30

    The hydrophobic properties of {gamma}-Al{sub 2}O{sub 3} membrane have been obtained by grafting fluoroalkylsilane (FAS) on the surface of the membrane. The following grafting parameters were studied: the eroding time of the original membrane, the grafting time, the concentration of FAS solution and the multiplicity of grafting. Hydrophobicity of the membranes was characterized by contact angle (CA) measurement. The thermogravimetric analysis (TGA) was used to investigate the weight loss process (25-800 deg. C) of the fluoroalkylsilane grafted on Al{sub 2}O{sub 3} powders under different grafting conditions. The morphologies of the membranes modified under different parameters were examined by field emission scanning electron microscopy (FE-SEM) and the surface roughness (Ra) was measured using white light interferometers. A needle-like structure was observed on the membrane surface after modification, which causes the change of Ra. On the results above, we speculated a model to describe the reaction between FAS and {gamma}-Al{sub 2}O{sub 3} membrane surface as well as the formed surface morphology.

  12. FAS grafted superhydrophobic ceramic membrane

    Science.gov (United States)

    Lu, Jun; Yu, Yun; Zhou, Jianer; Song, Lixin; Hu, Xingfang; Larbot, Andre

    2009-08-01

    The hydrophobic properties of γ-Al 2O 3 membrane have been obtained by grafting fluoroalkylsilane (FAS) on the surface of the membrane. The following grafting parameters were studied: the eroding time of the original membrane, the grafting time, the concentration of FAS solution and the multiplicity of grafting. Hydrophobicity of the membranes was characterized by contact angle (CA) measurement. The thermogravimetric analysis (TGA) was used to investigate the weight loss process (25-800 °C) of the fluoroalkylsilane grafted on Al 2O 3 powders under different grafting conditions. The morphologies of the membranes modified under different parameters were examined by field emission scanning electron microscopy (FE-SEM) and the surface roughness (Ra) was measured using white light interferometers. A needle-like structure was observed on the membrane surface after modification, which causes the change of Ra. On the results above, we speculated a model to describe the reaction between FAS and γ-Al 2O 3 membrane surface as well as the formed surface morphology.

  13. Interventions in Infrainguinal Bypass Grafts

    International Nuclear Information System (INIS)

    Mueller-Huelsbeck, S.; Order, B.-M.; Jahnke, T.

    2006-01-01

    The interventional radiologist plays an important role in the detection and prevention of infrainguinal bypass failure. Early detection and evaluation of flow-limiting lesions effectively preserve graft (venous bypass and polyester or expanded polytetrafluoroethylene bypass) patency by identifying stenoses before occlusion occurs. Delay in treatment of the at-risk graft may result in graft failure and a reduced chance of successful revascularization. For this reason, surveillance protocols form an important part of follow-up after infrainguinal bypass surgery. As well as having an understanding of the application of imaging techniques including ultrasound, MR angiography, CT angiography and digital subtraction angiography, the interventional radiologist should have detailed knowledge of the minimally invasive therapeutic options. Percutaneous transluminal angioplasty (PTA), or alternatively cutting balloon angioplasty, is the interventional treatment of choice in prevention of graft failure and occlusion. Further alternatives include metallic stent placement, fibrinolysis, and mechanical thrombectomy. Primary assisted patency rates following PTA can be up to 65% at 5 years. When the endovascular approach is unsuccessful, these therapeutic options are complemented by surgical procedures including vein patch revision, jump grafting, or placement of a new graft

  14. 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

  15. Magnetic resonance vascular imaging

    International Nuclear Information System (INIS)

    Axel, L

    1989-01-01

    The basis principles of MRI are reviewed in order to understand how blood flow effects arise in conventional imaging. Then some of the ways these effects have ben used in MRI techniques specifically designed for vascular imaging, are considered. (author)

  16. Percutaneous Endoluminal Stent-Graft Repair of an Old Traumatic Femoral Arteriovenous Fistula

    International Nuclear Information System (INIS)

    Uflacker, Renan; Elliott, Bruce M.

    1996-01-01

    A stent-graft was custom made to close a high-flow traumatic arteriovenous fistula of the left superficial femoral artery, present for 30 years, in a 60-year-old man with congestive heart failure and ischemic ulceration in the left foot. A balloon expandable Palmaz stent (P394; 2.5 mm x 3.9 cm) was covered with a polytetrafluoroethylene (PTFE) graft and was inserted percutaneously through an 11 Fr vascular sheath. Follow-up Doppler ultrasound at 6 months demonstrated occlusion of the arteriovenous fistula, patency of the artery, and luminal integrity of the artery and vein

  17. Angiographic findings of demineralised bone matrix grafts in femoral fracture repair in canines*

    International Nuclear Information System (INIS)

    Kumar, R.V.S.; Ramakrishna, O.

    2000-01-01

    Demineralised bone matrix implants and autogenous cancellous bone grafts were evaluated in femoral fracture repair with bone loss in canines, and compared to untreated animals. Angiograms were taken at 3,6,9 and 12 weeks post- operatively using conrary-420 as contrast medium. Early angiograms showed leakage of contrast medium into soft tissue. Grafted groups showed slight hypervascularity and enhanced capillary network. At 12 Weeks the same groups observed nearly normal persistent vascular supply. Early establishment of cortices continuity and draining of contrast medium via extraosseous veins was observed in demineralized bone matrix implanted groups

  18. Radiation grafting on natural films

    International Nuclear Information System (INIS)

    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. - Highlights: • Irradiation of zein

  19. In vitro model of vascularized bone: synergizing vascular development and osteogenesis.

    Directory of Open Access Journals (Sweden)

    Cristina Correia

    Full Text Available Tissue engineering provides unique opportunities for regenerating diseased or damaged tissues using cells obtained from tissue biopsies. Tissue engineered grafts can also be used as high fidelity models to probe cellular and molecular interactions underlying developmental processes. In this study, we co-cultured human umbilical vein endothelial cells (HUVECs and human mesenchymal stem cells (MSCs under various environmental conditions to elicit synergistic interactions leading to the colocalized development of capillary-like and bone-like tissues. Cells were encapsulated at the 1:1 ratio in fibrin gel to screen compositions of endothelial growth medium (EGM and osteogenic medium (OM. It was determined that, to form both tissues, co-cultures should first be supplied with EGM followed by a 1:1 cocktail of the two media types containing bone morphogenetic protein-2. Subsequent studies of HUVECs and MSCs cultured in decellularized, trabecular bone scaffolds for 6 weeks assessed the effects on tissue construct of both temporal variations in growth-factor availability and addition of fresh cells. The resulting grafts were implanted subcutaneously into nude mice to determine the phenotype stability and functionality of engineered vessels. Two important findings resulted from these studies: (i vascular development needs to be induced prior to osteogenesis, and (ii the addition of additional hMSCs at the osteogenic induction stage improves both tissue outcomes, as shown by increased bone volume fraction, osteoid deposition, close proximity of bone proteins to vascular networks, and anastomosis of vascular networks with the host vasculature. Interestingly, these observations compare well with what has been described for native development. We propose that our cultivation system can mimic various aspects of endothelial cell-osteogenic precursor interactions in vivo, and could find utility as a model for studies of heterotypic cellular interactions that

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

    Directory of Open Access Journals (Sweden)

    Ștefan Cristea

    2016-05-01

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

  1. Diffuse vascular damage in a transplanted kidney: an indication for nuclear magnetic resonance?

    Science.gov (United States)

    Burdese, M; Consiglio, V; Mezza, E; Savio, D; Guarena, C; Rossetti, M; Messina, M; Soragna, G; Suriani, C; Rabbia, C; Segoloni, G P; Piccoli, G B

    2005-06-01

    Vascular lesions are an increasing challenge after renal transplantation due to the wider indications for recipients and acceptance criteria for donors. Diagnostic approach and prognostic interpretation are still matter of controversy. The case reported herein may summarize some of the issues in this regard. A 54-year-old woman, on renal replacement therapy since 1974, and a kidney graft recipient from 1975 to 1999, received a second graft in 2001. The donor age was 65 years (cold ischemia 22 hours; two mismatches). The early posttransplant follow-up was characterized by delayed graft function, hypertension, and diabetes. During the initial hypertension workup, renal graft ultrasound (US) Doppler demonstrated increased vascular resistances, stable over time (resistance index 0.74 to 0.77); renal scintiscan displayed homogeneously parenchymoa and angio-magnetic resonance imaging (MRI), an homogeneous parenchymal vascularization. Initial immunosuppression with tacrolimus and steroids was modulated by adding mycophenolate mofetil to taper tacrolimus (to reduce nephrotoxicity and hypertension). Despite this, kidney function slowly deteriorated; serum creatinine reached 3 to 3.5 mg/dL by the second year. After a severe hypertensive crisis with unchanged scintiscan and US doppler examinations, angio-MRI revealed the almost complete disappearance of parenchymal enhancement beyond the lobar arteries. A renal biopsy confirmed the severe vascular damage. The patient was switched to rapamycine and a low-dose of an angiotension converting enzyme (ACE) inhibitor. She did relatively well (serum creatinine 2.2 to 3 mg/dL) for 6 months, when rapid functional impairment forced her to restart hemodialysis. This case, almost paradigmatic of the problems occurring when the rigid vasculature of long-term dialysis patients is matched with "marginal kidneys," suggests that MRI may be a sensible good to define vascular damage in the grafted kidney.

  2. Evolution of skin grafting for treatment of burns: Reverdin pinch grafting to Tanner mesh grafting and beyond.

    Science.gov (United States)

    Singh, Mansher; Nuutila, Kristo; Collins, K C; Huang, Anne

    2017-09-01

    Skin grafting is the current standard care in the treatment of full thickness burns. It was first described around 1500 BC but the vast majority of advancements have been achieved over the past 200 years. An extensive literature review was conducted on Pubmed, Medline and Google Scholar researching the evolution of skin grafting techniques. The authors concentrated on the major landmarks of skin grafting and also provide an overview of ongoing research efforts in this field. The major innovations of skin grafting include Reverdin pinch grafting, Ollier grafting, Thiersch grafting, Wolfe grafting, Padgett dermatome and modifications, Meek-wall microdermatome and Tanner mesh grafting. A brief description of the usage, advantages and limitations of each technique is included in the manuscript. Skin grafting technique have evolved significantly over past 200 years from Reverdin pinch grafting to modern day meshed skin grafts using powered dermatome. Increasing the expansion ratio and improving the cosmetic and functional outcome are the main focus of ongoing skin grafting research and emerging techniques (such as Integra ® , Recell ® , Xpansion ® ) are showing promise. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

  3. 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.

  4. Endovascular Treatment of Descending Thoracic Aortic Aneurysms with the EndoFit Stent-Graft

    International Nuclear Information System (INIS)

    Saratzis, N.; Saratzis, Athanasios; Melas, N.; Ginis, G.; Lioupis, A.; Lykopoulos, D.; Lazaridis, J.; Kiskinis, Dimitrios

    2007-01-01

    Objective. To evaluate the mid-term feasibility, efficacy, and durability of descending thoracic aortic aneurysm (DTAA) exclusion using the EndoFit device (LeMaitre Vascular). Methods. Twenty-three (23) men (mean age 66 years) with a DTAA were admitted to our department for endovascular repair (21 were ASA III+ and 2 refused open repair) from January 2003 to July 2005. Results. Complete aneurysm exclusion was feasible in all subjects (100% technical success). The median follow-up was 18 months (range 8-40 months). A single stent-graft was used in 6 cases. The deployment of a second stent-graft was required in the remaining 17 patients. All endografts were attached proximally, beyond the left subclavian artery, leaving the aortic arch branches intact. No procedure-related deaths have occurred. A distal type I endoleak was detected in 2 cases on the 1 month follow-up CT scan, and was repaired with reintervention and deployment of an extension graft. A nonfatal acute myocardial infarction occurred in 1 patient in the sixth postoperative month. Graft migration, graft infection, paraplegia, cerebral or distal embolization, renal impairment or any other major complications were not observed. Conclusion. The treatment of DTAAs using the EndoFit stent-graft is technically feasible. Mid-term results in this series are promising

  5. Kinetics of vein graft hyperplasia

    International Nuclear Information System (INIS)

    Zwolak, R.M.; Adams, M.C.; Clowes, A.W.

    1986-01-01

    Human aortocoronary vein grafts fail due to accelerated occlusive disease. The possibility that this is related to cellular hyperplasia was investigated in a rabbit model where kinetics of vein graft thickening, endothelial (EC) repair, and smooth muscle cell (SMC) proliferation were measured from 2 days to 24 weeks after implanting jugular vein segments in the carotid artery. Immediately after graft placement focal EC denudation was observed. These defects were repaired within 1 week and did not recur. By 4 weeks intimal area had increased 30 fold from 0.028 +/- 0.004 to 0.705 +/- 0.021 mm 2 , and a 24 weeks was 0.93 +/- 0.21 mm 2 . This response did not produce a reduction in graft lumen area. EC and SMC thymidine-labeling index were measured by en face and cross-section autoradiography after injection of 3 H-thymidine and perfusion fixation. Despite rapid EC surface repair EC labeling index remained elevated and only returned to normal levels at 12 weeks; SMC labeling was 10 fold greater than baseline even at 24 weeks (0.22% vs 0.02%). SMC mass demonstrated morphometrically increased between 2 and 12 weeks. Intimal thickening in vein grafts is due to SMC proliferation and develops after the EC layer has been restored. In contrast, intimal SMC proliferate in damaged arteries when the EC layer is absent and cease when the EC layer is regenerated

  6. Cost analysis of the Hemodialysis Reliable Outflow (HeRO) Graft compared to the tunneled dialysis catheter.

    Science.gov (United States)

    Al Shakarchi, Julien; Inston, Nicholas; Jones, Robert G; Maclaine, Grant; Hollinworth, David

    2016-04-01

    In end-stage renal disease patients with central venous obstruction, who have limited vascular access options, the Hemodialysis Reliable Outflow (HeRO) Graft is a new alternative with a lower incidence of complications and longer effective device life compared to tunneled dialysis catheters (TDCs). We undertook an economic analysis of introducing the HeRO Graft in the UK. A 1-year cost-consequence decision analytic model was developed comparing management with the HeRO Graft to TDCs from the perspective of the National Health Service in England. The model comprises four 3-month cycles during which the vascular access option either remains functional for hemodialysis or fails, patients can experience access-related infection and device thrombosis, and they can also accrue associated costs. Clinical input data were sourced from published studies and unit cost data from National Health Service 2014-15 Reference Costs. In the base case, a 100-patient cohort managed with the HeRO Graft experienced 6 fewer failed devices, 53 fewer access-related infections, and 67 fewer device thromboses compared to patients managed with TDCs. Although the initial device and placement costs for the HeRO Graft are greater than those for TDCs, savings from the lower incidence of device complications and longer effective device patency reduces these costs. Overall net annual costs are £2600 for each HeRO Graft-managed patient compared to TDC-managed patients. If the National Health Service were to reimburse hemodialysis at a uniform rate regardless of the type of vascular access, net 1-year savings of £1200 per patient are estimated for individuals managed with the HeRO Graft. The base case results showed a marginal net positive cost associated with vascular access with the HeRO Graft compared with TDCs for the incremental clinical benefit of reductions in patency failures, device-related thrombosis, and access-related infection events in a patient population with limited options for

  7. Overview of vascular disease

    International Nuclear Information System (INIS)

    Bisset, G.S. III

    1998-01-01

    Vascular disease in the pediatric population is a poorly understood process which is often underestimated in its incidence. The common beginnings of such ubiquitous diseases as atherosclerosis manifest themselves at a cellular level shortly after birth. Other common systemic disorders, including congestive heart failure and sepsis, are also intricately associated with dysfunctional vasculature. Progress in the understanding of normal and pathophysiologic processes within the vascular system begins with the 'control center' - the endothelial cell. The purpose of this review is to consolidate a body of knowledge on the processes that occur at the cellular level within the blood vessel wall, and to simplify the understanding of how imbalances in these physiologic parameters result in vascular disease. (orig.)

  8. Unstable patients with retroperitoneal vascular trauma: an endovascular approach.

    Science.gov (United States)

    Boufi, Mourad; Bordon, Sébastien; Dona, Bianca; Hartung, Olivier; Sarran, Anthony; Nadeau, Sébastien; Maurin, Charlotte; Alimi, Yves S

    2011-04-01

    In hemodynamically unstable patients, the management of retroperitoneal vascular trauma is both difficult and challenging. Endovascular techniques have become an alternative to surgery in several trauma centers. Between 2004 and 2006, 16 patients (nine men, mean age: 46 years, range: 19-79 years) with retroperitoneal vascular trauma and hemodynamic instability were treated using an endovascular approach. The mean injury severity score was 30.7 ± 13.1. Mean systolic blood pressure and the shock index were 74 mm Hg and 1.9, respectively. Vasopressor drugs were required in 68.7% of cases (n = 11). Injuries were attributable to road traffic accidents (n = 15) and falls (n = 1). The hemorrhage sites included the internal iliac artery or its branches (n = 12) with bilateral injury in one case, renal artery (n = 2), abdominal aorta (n = 1), and lumbar artery (n = 1). In all, 14 coil embolizations and three stent-grafts were implanted. The technical success rate was 75%, as early re-embolization was necessary in one case and three patients died during the perioperative period. Six patients died during the period of hospitalization (37.5%). No surgical conversion or major morbidity was reported. In comparison with particulates, coil ± stent-graft may provide similar efficacy with regard to survival, and thus may be a valuable solution when particulate embolization is not available or feasible. Copyright © 2011 Annals of Vascular Surgery Inc. Published by Elsevier Inc. All rights reserved.

  9. Outpatient Vascular Intervention: A Two-Year Experience

    International Nuclear Information System (INIS)

    Macdonald, Sumaira; Thomas, Steven M.; Cleveland, Trevor J.; Gaines, Peter A.

    2002-01-01

    Purpose: To retrospectively analyze the outcome of a range of interventional vascular procedures performed on outpatients. Methods: Suitability for outpatient procedures was assessed according to agreed protocols. An episode was defined as any procedure/s through a single access site at one attendance. Retrospective case-note review was performed. Results: There were 693 outpatient episodes between April 1998 and May 2000 (290 interventional, and 403 diagnostic procedures),comprising 25% (693/2769) of the total workload. Follow-up is available in 214; 38 of these were transfers from outlying hospitals and were excluded from analysis. One hundred and seventy-six were true outpatients. There were 98 iliac and 46 femoropopliteal interventions,2 aortic stents, 1 renal and 5 upper-limb angioplasties (PTAs), 5 embolizations, 8 Hickman lines, 1 line stripping, 3 atherectomies, 1 dialysis-graft PTA and 6 bypass-graft PTAs. Sixty-eight closure devices were used. Twelve patients were converted to inpatients (6.8%,12/176). The readmission rate was 3.4% (6/176). The reattendance rate was 1.1% (2/176), both subsequently attending for outpatient duplex ultrasound examination to exclude pseudoaneurysm. The major complication rate was 3.4% and the delayed major complication rate was 1.7%. Conclusion: Outpatient vascular intervention is safe with appropriate protocols and with careful patient selection. Local vascular services benefit from the release of inpatient beds

  10. [Recurrent vascular access trombosis associated with the prothrombin mutation G20210A in a adult patient in haemodialysis].

    Science.gov (United States)

    Quintana, L F; Coll, E; Monteagudo, I; Collado, S; López-Pedret, J; Cases, A

    2005-01-01

    Vascular access-related complications are a frequent cause of morbidity in haemodialysis patients and generate high costs. We present the case of an adult patient with end-stage renal disease and recurrent vascular access thrombosis associated with the prothrombin mutation G20210A and renal graft intolerance. The clinical expression of this heterozygous gene mutation may have been favoured by inflammatory state, frequent in dialysis patients. In this patient, the inflammatory response associated with the renal graft intolerance would have favored the development of recurrent vascular access thrombosis in a adult heterozygous for prothrombin mutation G20210A. In the case of early dysfunction of haemodialysis vascular access and after ruling out technical problems, it is convenient to carry out a screening for thrombophilia.

  11. Laser-assisted indocyanine green dye angiography accurately predicts the split-thickness graft timing of integra artificial dermis.

    Science.gov (United States)

    Fourman, Mitchell S; Phillips, Brett T; Fritz, Jason R; Conkling, Nicole; McClain, Steve A; Simon, Marcia; Dagum, Alexander B

    2014-08-01

    The use of an artificial dermal substitute such as Integra-a bilaminate combination of thin silicone and cross-linked bovine tendon collagen and chondroitin-6-sulfate-has become a popular method to address large surface area wounds or smaller, complex wounds devoid of a vascular bed. The incorporation of Integra depends on a vascular wound bed or periphery and can take 4 weeks or longer to occur. If the Integra has not fully incorporated at the time of placement of the split-thickness graft, complete graft loss may result. The availability of a minimally invasive method to assess the incorporation of Integra would be of great value. Two 5 × 10-cm paraspinal full-thickness wounds were created on 3 female swine. Wounds were randomly assigned full-thickness skin graft or Integra (Plainsboro, NJ) treatment. Both types of grafts were placed after the application of fibrin glue (Tisseel, Deerfield, Ill) to the wound bed. Laser Doppler imaging (LDI) (Moor), indocyanine green dye (ICG) angiography (LifeCell SPY), and clinical scoring were performed weekly for a period of 8 weeks after grafting. At 4 weeks, the silicone layer of the Integra was removed, and a culture of autologous keratinocytes was applied. A 4-mm punch biopsy sample of each graft was taken 1, 2, 4, 6, 7, and 8 weeks postoperatively for histologic analysis. Both ICG angiography and LDI perfusion measurements noted an increase in perfusion at the Integra graft site that peaked 3 weeks after grafting, corresponding with the start of neovascularization and the optimal time for the application of a split-thickness skin graft. indocyanine green dye angiography measurements exhibit greater reproducibility between animals at late time points as compared with LDI. This decrease in LDI precision is directly related to increases in scar tissue thickness of greater than 5 mm as determined via histologic analysis and corresponds with the accepted maximum penetration depth of the LDI laser. Indocyanine green dye

  12. PET/CT and vascular disease: Current concepts

    Energy Technology Data Exchange (ETDEWEB)

    Cavalcanti Filho, Jose Leite Gondim; Souza Leao Lima, Ronaldo de [CDPI and Multi-Imagem Clinics, Rio de Janeiro (Brazil); Department of Radiology, Rio de Janeiro Federal University (UFRJ), Rio de Janeiro (Brazil); Souza Machado Neto, Luiz de [CDPI and Multi-Imagem Clinics, Rio de Janeiro (Brazil); Kayat Bittencourt, Leonardo, E-mail: lkayat@terra.com.br [CDPI and Multi-Imagem Clinics, Rio de Janeiro (Brazil); Department of Radiology, Rio de Janeiro Federal University (UFRJ), Rio de Janeiro (Brazil); Cortes Domingues, Romeu [CDPI and Multi-Imagem Clinics, Rio de Janeiro (Brazil); Fonseca, Lea Mirian Barbosa da [CDPI and Multi-Imagem Clinics, Rio de Janeiro (Brazil); Department of Radiology, Rio de Janeiro Federal University (UFRJ), Rio de Janeiro (Brazil)

    2011-10-15

    Since its introduction in 2001, positron emission tomography associated to computed tomography (PET/CT) has been established as a standard tool in cancer evaluation. Being a multimodality imaging method, it combines in a single session the sensitivity granted by PET for detection of molecular targets within the picomolar range, with an underlying submilimetric resolution inherent to CT, that can precisely localize the PET findings. In this last decade, there have been new insights regarding the pathophysiology of atherosclerosis, particularly about plaque rupture and vascular remodeling. This has increased the interest for research on PET/CT in vascular diseases as a potential new diagnostic tool, since some PET molecular targets could identify diseases before the manifestation of gross anatomic features. In this review, we will describe the current applications of PET/CT in vascular diseases, emphasizing its usefulness in the settings of vasculitis, aneurysms, vascular graft infection, aortic dissection, and atherosclerosis/plaque vulnerability. Although not being properly peripheral vascular conditions, ischemic cardiovascular disease and cerebrovascular disease will be briefly addressed as well, due to their widespread prevalence and importance.

  13. Radiological findings and interventions for iatrogenic vascular injuries

    International Nuclear Information System (INIS)

    Lee, Kyoung Ho; Chung, Jin Wook; Kim, Tae Kyoung; Han, Sang Wook; Lee, Jong Seog; Park, Jae Hyung; Kim, Jong Hyo; Han, Man Chung

    1998-01-01

    The purpose of this study is to evaluate the radiological findings and effectiveness of radiological interventions in patients with iatrogenic vascular injuries. We analyzed 50 patients with iatrogenic vascular injuries treated with radiological intervention. The causes of injuries were surgery (n=20), cardiovascular intervention (n=15), non-cardiovascular radiological intervention (n=14), and endoscopic intervention (n=1). The injury had resulted in hemorrhage in 35 cases. The iliac and/or femoral, hepatic, and renal vessels were commonly injured. Angiography, ultrasonography with Doppler examination, CT, and CT angiography were performed to diagnose vascular injuries and guide the radiological intervention. The mean follow-up period was 23 months and in 16 cases was more than one year. the major radiological findings were extravasation, pseudoaneurysm, arteriovenous shunt, or vascular obstruction. To control these lesions, radiological interventions such as embolization (n=36), local urokinase administration, stent insertion, foreign body removal, ultrasonography-guided compression, or stent-graft insertion were performed. The clinical problems were immediately controlled by the single trials of radiological interventions and did not recur in 40 cases (80%). Radiological examinations and interventions are useful in cases with iatrogenic vascular injuries. (author). 14 refs., 4 figs

  14. Vascular Augmentation in Renal Transplantation: Supercharging and Turbocharging

    Directory of Open Access Journals (Sweden)

    Euicheol C. Jeong

    2017-05-01

    Full Text Available The most common anatomic variant seen in donor kidneys for renal transplantation is the presence of multiple renal arteries, which can cause an increased risk of complications. Accessory renal arteries should be anastomosed to the proper source arteries to improve renal perfusion via the appropriate vascular reconstruction techniques. In microsurgery, 2 kinds of vascular augmentation methods, known as ‘supercharging’ and ‘turbocharging,’ have been introduced to ensure vascular perfusion in the transferred flap. Supercharging uses a distant source of the vessels, while turbocharging uses vascular sources within the same flap territory. These technical concepts can also be applied in renal transplantation, and in this report, we describe 2 patients who underwent procedures using supercharging and turbocharging. In one case, the ipsilateral deep inferior epigastric artery was transposed to the accessory renal artery (supercharging, and in the other case, the accessory renal artery was anastomosed to the corresponding main renal artery with a vascular graft (turbocharging. The transplanted kidneys showed good perfusion and proper function. No cases of renal failure, hypertension, rejection, or urologic complications were observed. These microsurgical techniques can be safely utilized for renal transplantation with donor kidneys that have multiple arteries with a lower complication rate and better outcome.

  15. Vascular Augmentation in Renal Transplantation: Supercharging and Turbocharging.

    Science.gov (United States)

    Jeong, Euicheol C; Hwang, Seung Hwan; Eo, Su Rak

    2017-05-01

    The most common anatomic variant seen in donor kidneys for renal transplantation is the presence of multiple renal arteries, which can cause an increased risk of complications. Accessory renal arteries should be anastomosed to the proper source arteries to improve renal perfusion via the appropriate vascular reconstruction techniques. In microsurgery, 2 kinds of vascular augmentation methods, known as 'supercharging' and 'turbocharging,' have been introduced to ensure vascular perfusion in the transferred flap. Supercharging uses a distant source of the vessels, while turbocharging uses vascular sources within the same flap territory. These technical concepts can also be applied in renal transplantation, and in this report, we describe 2 patients who underwent procedures using supercharging and turbocharging. In one case, the ipsilateral deep inferior epigastric artery was transposed to the accessory renal artery (supercharging), and in the other case, the accessory renal artery was anastomosed to the corresponding main renal artery with a vascular graft (turbocharging). The transplanted kidneys showed good perfusion and proper function. No cases of renal failure, hypertension, rejection, or urologic complications were observed. These microsurgical techniques can be safely utilized for renal transplantation with donor kidneys that have multiple arteries with a lower complication rate and better outcome.

  16. Author disclosure of conflict of interest in vascular surgery journals.

    Science.gov (United States)

    Forbes, Thomas L

    2011-09-01

    Advances in vascular surgery are increasingly technology-driven, and the relationships between surgeons and the medical device industry can be complex. This study reviewed conflict of interest (COI) disclosure in the vascular surgery journals regarding several selected technology-driven topics, including endovascular stent grafts (EV), carotid artery stenting (CAS), and peripheral arterial interventions (PI), to suggest further directions. Authors' COI disclosures were reviewed from all clinical papers published in 2008 and 2009 in each of six vascular surgery journals, and pertaining to three selected topics (EV, CAS, and PI). Rate of COI disclosure was evaluated as a function of journal, topic, article type (randomized trial, case series, case report, review, or meta-analysis), and authors' region of origin. Secondarily, consistency of authors' disclosure was evaluated by reviewing papers by the same author and of the same topic. Six hundred thirty-five papers were reviewed from the six journals. A COI was declared in 125 (19.7%) of these papers. This rate differed between journals (range, 3.2%-34.1%; P journals (46.9%), or in the same journal (25%). Rates of disclosure of COI, and inconsistencies in disclosure in the vascular surgery literature are at least partially due to differences in journals' reporting policies, while a smaller proportion of these inconsistencies are due to individual author behavior. Journals should adopt a consistent requirement for a separate COI declaration where all relevant financial arrangements are disclosed. Copyright © 2011 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  17. Grafted SiC nanocrystals

    DEFF Research Database (Denmark)

    Saini, Isha; Sharma, Annu; Dhiman, Rajnish

    2017-01-01

    ), raman spectroscopy and X-ray diffraction (XRD) measurements. UV–Visible absorption spectroscopy was used to study optical properties such as optical energy gap (Eg), Urbach's energy (Eu), refractive index (n), real (ε1) and imaginary (ε2) parts of dielectric constant of PVA as well as PVA......Polyvinyl alcohol (PVA) grafted SiC (PVA-g-SiC)/PVA nanocomposite was synthesized by incorporating PVA grafted silicon carbide (SiC) nanocrystals inside PVA matrix. In-depth structural characterization of resulting nanocomposite was carried out using fourier transform infrared spectroscopy (FTIR...

  18. Endovascular treatment of external iliac vein stenosis caused by graft compression after kidney transplantation

    Directory of Open Access Journals (Sweden)

    Willamax Oliveira de Sousa

    2013-06-01

    Full Text Available A 57-year old patient presented with approximately 80% stenosis of the left external iliac vein due to compression by the renal graft after kidney transplantation. The initial clinical manifestation of this vascular complication was progressive edema of the left lower limb, starting in the foot during the immediate postoperative period and reaching the thigh. Renal function also deteriorated during the first four months after transplantation. Venous Doppler ultrasound findings were suggestive of a diagnosis of extrinsic compression by the kidney graft and so phlebography was ordered, confirming stenosis of the left external iliac vein. The patient was initially treated with balloon angioplasty, but there was still residual stenosis so a stent was inserted, eliminating the stenosis. The edema reduced over time and the patient's renal function improved. While vascular complications are rare, and potentially severe, events, success rates are good if treatment is started early.

  19. Oral mucosa grafts for urethral reconstruction

    African Journals Online (AJOL)

    reports reveal that split and full thickness skin grafts from the scrotum, penis, extragenital sites (ureter, saphenous .... Table 1: Summary of the history of oral mucosa grafts for urethroplasty .... advised that care should be taken when suturing the.

  20. Does treatment of split-thickness skin grafts with negative-pressure wound therapy improve tissue markers of wound healing in a porcine experimental model?

    Science.gov (United States)

    Ward, Christopher; Ciraulo, David; Coulter, Michael; Desjardins, Steven; Liaw, Lucy; Peterson, Sarah

    2012-08-01

    Negative-pressure wound therapy (NPWT) has been used for to treat wounds for more than 15 years and, more recently, has been used to secure split-thickness skin grafts. There are some data to support this use of NPWT, but the actual mechanism by which NPWT speeds healing or improves skin graft take is not entirely known. The purpose of this project was to assess whether NPWT improved angiogenesis, wound healing, or graft survival when compared with traditional bolster dressings securing split-thickness skin grafts in a porcine model. We performed two split-thickness skin grafts on each of eight 30 kg Yorkshire pigs. We took graft biopsies on postoperative days 2, 4, 6, 8, and 10 and submitted the samples for immunohistochemical staining, as well as standard hematoxylin and eosin staining. We measured the degree of vascular ingrowth via immunohistochemical staining for von Willenbrand's factor to better identify blood vessel epithelium. We determined the mean cross-sectional area of blood vessels present for each representative specimen, and then compared the bolster and NPWT samples. We also assessed each graft for incorporation and survival at postoperative day 10. Our analysis of the data revealed that there was no statistically significant difference in the degree of vascular ingrowth as measured by mean cross-sectional capillary area (p = 0.23). We did not note any difference in graft survival or apparent incorporation on a macroscopic level, although standard hematoxylin and eosin staining indicated that microscopically, there seemed to be better subjective graft incorporation in the NPWT samples and a nonsignificant trend toward improved graft survival in the NPWT group. We were unable to demonstrate a significant difference in vessel ingrowth when comparing NPWT and traditional bolster methods for split-thickness skin graft fixation. More studies are needed to elucidate the manner by which NPWT exerts its effects and the true clinical magnitude of these

  1. 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.

  2. Non-invasive assessment of coronary artery bypass graft patency using 16-slice computed tomography angiography

    Directory of Open Access Journals (Sweden)

    Uren Neal G

    2007-06-01

    Full Text Available Abstract Background Invasive coronary angiography is the gold standard means of imaging bypass vessels and carries a small but potentially serious risk of local vascular complications, including myocardial infarction, stroke and death. We evaluated computed tomography as a non-invasive means of assessing graft patency. Methods Fifty patients with previous coronary artery bypass surgery who were listed for diagnostic coronary angiography underwent contrast enhanced computed tomography angiography using a 16-slice computed tomography scanner. Images were retrospectively gated to the electrocardiogram and two dimensional axial, multiplanar and three dimensional reconstructions acquired. Sensitivity, specificity, positive and negative predictive value, accuracy and level of agreement for detection of graft patency by multidetector computed tomography. Results A total of 116 grafts were suitable for analysis. The specificity of CT for the detection of graft patency was 100%, with a sensitivity of 92.8%, positive predictive value 100%, negative predictive value 85.8% and an accuracy of 94.8%. The kappa value of agreement between the two means of measuring graft patency was 0.9. Mean radiation dose was 9.0 ± 7.2 mSv for coronary angiography and 18.5 ± 4 mSv for computed tomography. Pooled analysis of eight studies, incorporating 932 grafts, confirmed a 97% accuracy for the detection of graft patency by multidetector computed tomography. Conclusion Computed tomography is an accurate, rapid and non-invasive method of assessing coronary artery bypass graft patency. However, this was achieved at the expense of an increase in radiation dose.

  3. Evaluation of Replacement Grafts and Punch Grafts in the Treatment of Vitiligo

    Directory of Open Access Journals (Sweden)

    Singh Ajit Kumar

    1980-01-01

    Full Text Available Thirtycasesof vitiligo eachwithminimum of two lesions undent replacement graft and multiple punch grafts in one lesion each. Complications observed at the recipient site like infection and raised nigosed surface were significantly more in replacement grafts. Hypopigmentation of the graft was significantly more when the disease was progressive.

  4. Management of an irradiated anophthalmic socket following dermis-fat graft rejection: A case report

    Directory of Open Access Journals (Sweden)

    Raizada Kuldeep

    2008-01-01

    Full Text Available Dermis-fat graft (DFG is often the only promising option in cases of severely contracted sockets. However, there is an increased risk of graft failure in irradiated sockets with decreased vascularity. In such difficult cases, repeat DFG implantation also has higher risks of graft failure. We describe an ingenious method of successful management of an irradiated anophthalmic socket following DFG infection and necrosis, with acceptable cosmetic results. At surgery, an orbital impression was taken with ophthalmic grade alginate. Based on this measurement, a custom-made stem pressure socket-expander made up of high density polymethyl methacrylate (PMMA was fitted, a week post surgery and kept in situ for six weeks. On review, the fornices had considerably deepened. The expander device was removed and the patient was now fitted with a custom-made thicker prosthesis made up of high-density PMMA. The patient has followed up for a year subsequently and the prosthesis has remained stable.

  5. The noncovalent bonding of antibiotics to a polytetrafluoroethylene-benzalkonium graft

    International Nuclear Information System (INIS)

    Harvey, R.A.; Greco, R.S.

    1981-01-01

    This study evaluates the noncovalent bonding of anionic antibiotics to polytetrafluoroethylene grafts using benzalkonium chloride as a cationic anchor. The binding of radiolabeled surfactants and antibiotics was evaluated by liquid scintillation and in an in vitro microbiologic assay against Staphylococcus aureus. Significant quantities of antibiotic were bound when the grafts were pretreated with benzalkonium in ethanol or aqueous solution at elevated temperature. Bound antibiotic is stable in aqueous salt solutions, but slowly dissociates in the presence of blood or serum. The ionic nature of the bonding process is clarified by the use of a variety of antibiotics and surfactants with complementary charges. The ability of the benzalkonium treated grafts to adsorb antibiotic from blood is, likewise, demonstrated and the possibility of concomitantly binding heparin and antibiotic simultaneously is evaluated. These studies support the ability to noncovalently bond antibiotics to polytetrafluoroethylene surfaces and form the basis of eventually utilizing these surfaces in the prevention of vascular prosthetic infections

  6. Immediate Regrafting of the Split Thickness Skin Graft Donor Site Assists Healing.

    Science.gov (United States)

    Bradow, Brian P; Hallock, Geoffrey G; Wilcock, Samuel P

    2017-05-01

    Delayed or even lack of healing of a split-thickness skin graft (STSG) donor site is a potential problem with elderly patients or those with poor wound healing capabilities. A proactive solution that may minimize this risk is to regraft that donor site using otherwise discarded skin graft remnants. A prospective, nonrandomized, consecutive study was designed to compare the time to healing of the commonly used anterior thigh STSG donor site in patients who had routine dressings (n = 113) versus those with comorbidities known to adversely affect wound healing and had planned regrafting (n = 204). Those comorbidities included age (≥65 years), diabetes mellitus, peripheral vascular disease, chronic renal disease, and chronic steroid use. The average number of comorbidities in the regrafted subgroup versus those not regrafted was 1.41 and 0.31, respectively. This was considered to be a significant difference ( P skin graft materials when so indicated and can be a proactive solution to a potentially cumbersome dilemma.

  7. Hierarchical Fabrication of Engineered Vascularized Bone Biphasic Constructs via Dual 3D Bioprinting: Integrating Regional Bioactive Factors into Architectural Design.

    Science.gov (United States)

    Cui, Haitao; Zhu, Wei; Nowicki, Margaret; Zhou, Xuan; Khademhosseini, Ali; Zhang, Lijie Grace

    2016-09-01

    A biphasic artificial vascularized bone construct with regional bioactive factors is presented using dual 3D bioprinting platform technique, thereby forming a large functional bone grafts with organized vascular networks. Biocompatible mussel-inspired chemistry and "thiol-ene" click reaction are used to regionally immobilize bioactive factors during construct fabrication for modulating or improving cellular events. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Endothelial cells on PET vascular prostheses impregnated with polyester-based copolymers and coated with cell-adhesive protein assemblies

    Czech Academy of Sciences Publication Activity Database

    Chlupáč, Jaroslav; Filová, Elena; Riedel, Tomáš; Brynda, Eduard; Pamula, E.; Lisá, Věra; Bačáková, Lucie

    2008-01-01

    Roč. 11, 81-84 (2008), s. 108-111 ISSN 1429-7248 R&D Projects: GA AV ČR(CZ) 1QS500110564 Grant - others:GA AV ČR(CZ) IAA400500507; Polish Ministry of Science(PL) 3T08D01928 Program:IA Institutional research plan: CEZ:AV0Z50110509; CEZ:AV0Z40500505 Keywords : bioarteficial vascular grafts * vascular tissue engineering Subject RIV: EI - Biotechnology ; Bionics

  9. THE RESULT OF INTRAMEDULLARY NAILING WITH BONE GRAFTING OF TIBIA'S PATHOLOGIC FRACTURE

    Directory of Open Access Journals (Sweden)

    V. M. Shapovalov

    2010-01-01

    Full Text Available The authors give the clinical case of successful surgical treatment of patient with tibia's pathologic fracture by intramedullary nailing with bone grafting. The disadvantages of such patients' treatment by plaster immobilization and by some invasive methods like vascular autografting by Ilizarov's method and bone plating were also discussed. The obvious benefits of proposed surgical treatment technique of observed patient category are shown.

  10. Towards retrievable vascularized bioartificial pancreas: induction and long-lasting stability of polymeric mesh implant vascularized with the help of acidic and basic fibroblast growth factors and hydrogel coating.

    Science.gov (United States)

    Prokop, A; Kozlov, E; Nun Non, S; Dikov, M M; Sephel, G C; Whitsitt, J S; Davidson, J M

    2001-01-01

    We seek to improve existing methodologies for allogenic grafting of pancreatic islets. The lack of success of encapsulated transplanted islets inside the peritoneal cavity is presently attributed to poor vascularization of the implant. A thick, fibrotic capsule often surrounds the graft, limiting survival. We have tested the hypothesis that neovascularization of the graft material can be induced by the addition of proper angiogenic factors embedded within a polymeric coat. Biocompatible and nonresorbable meshes coated with hydrophilic polymers were implanted in rats and harvested after 1-, 6-, and 12-week intervals. The implant response was assessed by histological observations on the degree of vascularity, fibrosis, and inflammation. Macrostructural geometry of meshes was conducive to tissue ingrowth into the interstitial space between the mesh filaments. Hydrogel coating with incorporated acidic or basic FGF in an electrostatic complex with polyelectrolytes and/or with heparin provided a sustained slow release of the angiogenic growth factor. Anti-factor VIII and anti-collagen type IV antibodies and a GSL I-B4 lectin were used to measure the extent of vascularization. Vigorous and persistent vascularization radiated several hundred microns from the implant. The level of vascularization should provide a sufficient diffusion of nutrients and oxygen to implanted islets. Based on our observations, stable vascularization may require a sustained angiogenic signal to allow for the development of a permanent implant structure.

  11. 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

  12. [Vascular complications following kidney transplant: the role of color-Doppler imaging].

    Science.gov (United States)

    Granata, Antonio; Floccari, Fulvio; Lentini, Paolo; Vittoria, Salvatore; Di Pietro, Fabio; Zamboli, Pasquale; Fiorini, Fulvio; Fatuzzo, Pasquale

    2012-01-01

    The progressive decline in the incidence of graft rejection has made urological, surgical, parenchymal and vascular complications of kidney transplant more frequent. The latter, although accounting for only 5-10% of all post-transplant complications, are a frequent cause of graft loss. Ultrasonography, both in B-mode and with Doppler ultrasound, is an important diagnostic tool in case of clinical conditions which might impair kidney function. Even though ultrasonography is considered fundamental in the diagnosis of parenchymal and surgical complications of the transplanted kidney, its role is not fully understood in case of vascular complications of the graft. The specificity of Doppler ultrasound is very important in case of stenosis of the transplanted renal artery, pseudoaneurysms, arteriovenous fistulas, and thrombosis with complete or partial artery or vein occlusion. Doppler and color determinations present high diagnostic accuracy, which is higher in case of successive measurements performed during the follow-up of the graft. Modern techniques including contrast-enhanced ultrasound increase the diagnostic power of ultrasonography in case of vascular complications of the transplanted kidney, planted kidney.

  13. The effects of different schedules of total-body irradiation in heterotopic vascularized bone transplantation. An experimental study in the Lewis rat

    International Nuclear Information System (INIS)

    Gonzalez del Pino, J.; Benito, M.; Randolph, M.A.; Weiland, A.J.

    1990-01-01

    To evaluate the effects of irradiation on heterotopically placed vascularized knee isografts, a single dose of 10 Gy of total-body irradiation was given to Lewis donor rats. Irradiation was delivered either 2 or 6 days prior to harvesting or subsequent transplantation, and evaluated at 1, 2, and 4 weeks after grafting. Irradiation caused endothelial depopulation of the graft artery, although vascular pedicle patency was maintained throughout the study. Bone graft viability and mineralization were normal. Dramatic changes in the bone marrow were seen that included an increase of its fat content (P less than 0.001), and a concomitant decrease in bone marrow-derived immunocompetent cells. These changes were more prominent in recipients of grafts from day -6 irradiated donor rats. Total-body irradiation did not prejudice the use of vascularized bone grafts, and exhibited an associated immunosuppresant effect over the vascular endothelium and bone marrow. This may be a further rational conditioning procedure to avoid recipient manipulation in vascularized bone allotransplantation

  14. Management of aortic graft infections - the present strategy and future perspectives.

    Science.gov (United States)

    Treska, V; Certik, B; Molacek, J

    2016-01-01

    Aortic graft infections (AGI) are serious complications of open and endovascular types of surgery with an incidence rate of 0.6-3 %. AGI are associated with 30-60 % perioperative mortality and 40-60 % morbidity rate with limb amputation rates between 10 % and 40 %. The economic cost of AGI is substantial. At the time of aortic reconstruction, almost 90 % of patients have one or more predisposing factors for AGI. The diagnosis is based on clinical symptomatology, laboratory markers, microbial cultures, and imaging modalities. The general principle of surgical treatment lies in the removal of infected graft, debridement of infected periprosthetic tissues, and vascular reconstruction by in situ or extra-anatomic bypass with long-term antibiotic therapy. The conservative treatment is used only for selected patients with endograft infection. This review summarizes the current knowledge about the incidence, predisposing factors, etiology, diagnosis, treatment options, and prevention of aortic vascular graft and endograft infections. With the growing number of endovascular procedures we can expect more cases of infected aortic endografts in patients with severe comorbidities in the near future, where the recent radical surgical approach (graft excision, debridement, and new revascularization) cannot be used. Therefore the less invasive, sophisticated and individualized treatment strategies will have to be used in search of the best therapeutic approach to each specific patient (Fig. 4, Ref. 82).

  15. Straight configuration saphenous vein transposition to popliteal artery for vascular access.

    Science.gov (United States)

    Caco, Gentian; Golemi, Dhurata; Likaj, Eriola

    2017-03-21

    The saphenous vein is commonly used as a vascular graft in peripheral artery surgery but rarely used for vascular access. The literature on straight configuration saphenous vein transposition to the popliteal artery is scarce. Here we present two cases of straight configuration saphenous vein transposition to the popliteal artery for vascular access, the surgical technique and respective follow-up. Two young men, aged 29 and 36 years, were chosen for lower-limb vascular access for hemodialysis. The first patient was paraplegic since birth. He used his arms to move so upper extremity vascular access was avoided. The second patient presented with an infected upper extremity arteriovenous graft (AVG) and after multiple closed AVFs he had no more available arm veins. Both patients received autologous lower extremity straight configuration saphenous vein transpositions to the popliteal artery under spinal anesthesia in May and October 2012, respectively. Cannulation of the fistula was allowed after one month. There were no early complications. Slight swelling on the leg appeared in one of the patients. Both fistulas were still functional after 36 and 32 months, respectively. The straight configuration saphenous vein transposition to popliteal artery is simple to perform, offers a long and straight segment for cannulation and may be a suitable autologous vascular access in selected patients.

  16. Vascular access choice in incident hemodialysis patients: a decision analysis.

    Science.gov (United States)

    Drew, David A; Lok, Charmaine E; Cohen, Joshua T; Wagner, Martin; Tangri, Navdeep; Weiner, Daniel E

    2015-01-01

    Hemodialysis vascular access recommendations promote arteriovenous (AV) fistulas first; however, it may not be the best approach for all hemodialysis patients, because likelihood of successful fistula placement, procedure-related and subsequent costs, and patient survival modify the optimal access choice. We performed a decision analysis evaluating AV fistula, AV graft, and central venous catheter (CVC) strategies for patients initiating hemodialysis with a CVC, a scenario occurring in over 70% of United States dialysis patients. A decision tree model was constructed to reflect progression from hemodialysis initiation. Patients were classified into one of three vascular access choices: maintain CVC, attempt fistula, or attempt graft. We explicitly modeled probabilities of primary and secondary patency for each access type, with success modified by age, sex, and diabetes. Access-specific mortality was incorporated using preexisting cohort data, including terms for age, sex, and diabetes. Costs were ascertained from the 2010 USRDS report and Medicare for procedure costs. An AV fistula attempt strategy was found to be superior to AV grafts and CVCs in regard to mortality and cost for the majority of patient characteristic combinations, especially younger men without diabetes. Women with diabetes and elderly men with diabetes had similar outcomes, regardless of access type. Overall, the advantages of an AV fistula attempt strategy lessened considerably among older patients, particularly women with diabetes, reflecting the effect of lower AV fistula success rates and lower life expectancy. These results suggest that vascular access-related outcomes may be optimized by considering individual patient characteristics. Copyright © 2015 by the American Society of Nephrology.

  17. The caudal septum replacement graft.

    Science.gov (United States)

    Foda, Hossam M T

    2008-01-01

    To describe a technique for reconstructing the lost tip support in cases involving caudal septal and premaxillary deficiencies. The study included 120 patients with aesthetic and functional nasal problems resulting from the loss of caudal septal and premaxillary support. An external rhinoplasty approach was performed to reconstruct the lost support using a cartilaginous caudal septum replacement graft and premaxillary augmentation with Mersilene mesh. The majority of cases (75%) involved revisions in patients who had previously undergone 1 or more nasal surgical procedures. A caudal septum replacement graft was combined with premaxillary augmentation in 93 patients (77.5%). The mean follow-up period was 3 years (range, 1-12 years). The technique succeeded in correcting the external nasal deformities in all patients and resulted in a significant improvement in breathing in 74 patients (86%) with preoperative nasal obstruction. There were no cases of infection, displacement, or extrusion. The caudal septum replacement graft proved to be very effective in restoring the lost tip support in patients with caudal septal deficiency. Combining the graft with premaxillary augmentation using Mersilene mesh helped increase support and stability over long-term follow-up.

  18. ACL Graft Healing and Biologics

    NARCIS (Netherlands)

    Muller, Bart; Bowman, Karl F.; Bedi, Asheesh

    2013-01-01

    Operative reconstruction of a torn anterior cruciate ligament (ACL) has become the most broadly accepted treatment. An important, but underreported, outcome of ACL reconstruction is graft failure, which poses a challenge for the orthopedic surgeon. An understanding of the tendon-bone healing and the

  19. Polyether-polyester graft copolymer

    Science.gov (United States)

    Bell, Vernon L. (Inventor)

    1987-01-01

    Described is a polyether graft polymer having improved solvent resistance and crystalline thermally reversible crosslinks. The copolymer is prepared by a novel process of anionic copolymerization. These polymers exhibit good solvent resistance and are well suited for aircraft parts. Previous aromatic polyethers, also known as polyphenylene oxides, have certain deficiencies which detract from their usefulness. These commercial polymers are often soluble in common solvents including the halocarbon and aromatic hydrocarbon types of paint thinners and removers. This limitation prevents the use of these polyethers in structural articles requiring frequent painting. In addition, the most popular commercially available polyether is a very high melting plastic. This makes it considerably more difficult to fabricate finished parts from this material. These problems are solved by providing an aromatic polyether graft copolymer with improved solvent resistance and crystalline thermally reversible crosslinks. The graft copolymer is formed by converting the carboxyl groups of a carboxylated polyphenylene oxide polymer to ionic carbonyl groups in a suitable solvent, reacting pivalolactone with the dissolved polymer, and adding acid to the solution to produce the graft copolymer.

  20. 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.

  1. Endovascular repair of early rupture of Dacron aortic graft--two case reports.

    LENUS (Irish Health Repository)

    Sultan, Sherif

    2005-01-01

    Complications after open aortic surgery pose a challenge both to the vascular surgeon and the patient because of aging population, widespread use of cardiac revascularization, and improved survival after aortic surgery. The perioperative mortality rate for redo elective aortic surgery ranges from 5% to 29% and increases to 70-100% in emergency situation. Endovascular treatment of the postaortic open surgery (PAOS) patient has fewer complications and a lower mortality rate in comparison with redo open surgical repair. Two cases of ruptured abdominal aortic aneurysm (AAA) were managed with the conventional open surgical repair. Subsequently, spiral contrast computer tomography scans showed reperfusion of the AAA sac remnant mimicking a type III endoleak. These graft-related complications presented as vascular emergencies, and in both cases endovascular aneurysm repair (EVAR) procedure was performed successfully by aortouniiliac (AUI) stent graft and femorofemoral crossover bypass. These 2 patients add further merit to the cases reported in the English literature. This highlights the crucial importance of endovascular grafts in the management of such complex vascular problems.

  2. Comparison of graft survival following penetrating keratoplasty and Descemet's stripping endothelial keratoplasty in eyes with a glaucoma drainage device.

    Science.gov (United States)

    Iverson, Shawn M; Spierer, Oriel; Papachristou, George C; Feuer, William J; Shi, Wei; Greenfield, David S; O'Brien, Terrence P

    2018-02-01

    To compare corneal graft survival rates after penetrating keratoplasty (PK) and Descemet's stripping endothelial keratoplasty (DSEK) in patients with a glaucoma drainage device (GDD) or medically managed glaucoma. A retrospective chart review was conducted on consecutive patients who underwent primary PK or primary DSEK. Inclusion criteria consisted of eyes with a diagnosis of glaucoma prior to corneal transplantation and a minimum of 6 months of follow-up. Graft failure was defined as an edematous cornea with failure to maintain deturgescence lasting beyond a period of 1 month of intense steroid therapy or vascularization and scarring resulting in irreversible loss of central graft clarity. Corneal graft survival was calculated using Kaplan-Meier survival analysis. Patients were divided into four groups: GDD-PK, GDD-DSEK, medical-PK and medical-DSEK. Fifty-six eyes of 56 patients were identified as meeting inclusion criteria. Among eyes with a GDD, there was no difference in the proportion of failures between PK grafts (48%) and DSEK grafts (50%) (p = 0.90). Failure occurred earlier in DSEK recipients compared to PK recipients, 5.82 ± 6.77 months versus 14.40 ± 7.70 months, respectively (p = 0.04). A Kaplan-Meier analysis did not identify a difference between the four groups with respect to graft failure (p = 0.52). There is no significant difference in graft survival rates between medically and surgically treated glaucoma patients for either PK or DSEK grafts. In patients with GDD, graft failure occurs earlier in DSEK compared to PK.

  3. Graft type for femoro-popliteal bypass surgery.

    Science.gov (United States)

    Ambler, Graeme K; Twine, Christopher P

    2018-02-11

    Femoro-popliteal bypass is implemented to save limbs that might otherwise require amputation, in patients with ischaemic rest pain or tissue loss; and to improve walking distance in patients with severe life-limiting claudication. Contemporary practice involves grafts using autologous vein, polytetrafluoroethylene (PTFE) or Dacron as a bypass conduit. This is the second update of a Cochrane review first published in 1999 and last updated in 2010. To assess the effects of bypass graft type in the treatment of stenosis or occlusion of the femoro-popliteal arterial segment, for above- and below-knee femoro-popliteal bypass grafts. For this update, the Cochrane Vascular Information Specialist searched the Vascular Specialised Register (13 March 2017) and CENTRAL (2017, Issue 2). Trial registries were also searched. We included randomised trials comparing at least two different types of femoro-popliteal grafts for arterial reconstruction in patients with femoro-popliteal ischaemia. Randomised controlled trials comparing bypass grafting to angioplasty or to other interventions were not included. Both review authors (GKA and CPT) independently screened studies, extracted data, assessed trials for risk of bias and graded the quality of the evidence using GRADE criteria. We included nineteen randomised controlled trials, with a total of 3123 patients (2547 above-knee, 576 below-knee bypass surgery). In total, nine graft types were compared (autologous vein, polytetrafluoroethylene (PTFE) with and without vein cuff, human umbilical vein (HUV), polyurethane (PUR), Dacron and heparin bonded Dacron (HBD); FUSION BIOLINE and Dacron with external support). Studies differed in which graft types they compared and follow-up ranged from six months to 10 years.Above-knee bypassFor above-knee bypass, there was moderate-quality evidence that autologous vein grafts improve primary patency compared to prosthetic grafts by 60 months (Peto odds ratio (OR) 0.47, 95% confidence interval (CI

  4. Flash pulmonary oedema after relief of haemodialysis graft stenosis.

    Science.gov (United States)

    Vélez-Martínez, Mariella; Weinberg, Brent D; Mishkin, Joseph D

    2013-08-01

    Heart failure (HF) and chronic kidney disease (CKD) are undoubtedly very much interrelated, especially in patients with end-stage renal disease (ESRD) who are dependent on renal replacement therapy. Haemodialysis (HD) is of particular interest in cardiovascular patients due to the creation of a haemodialysis vascular access and the haemodynamic changes associated with it. Adequate HD though is very dependent on a properly functioning vascular access. Unfortunately, these surgical vascular accesses are vulnerable to stenoses and occlusions. Percutaneous endovascular treatment of these stenoses is often performed and has been found to be safe and effective. Despite its frequent use, acute medical complications of this percutaneous procedure have not been well-documented. In this report, we describe a patient who developed flash pulmonary oedema after balloon angioplasty treatment of an arteriovenous graft (AVG) stenosis. Copyright © 2012 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  5. Homogeneous cation exchange membrane by radiation grafting

    International Nuclear Information System (INIS)

    Kolhe, Shailesh M.; G, Agathian; Ashok Kumar

    2001-01-01

    Preparation of a strong cation exchange membrane by radiation grafting of styrene on to polyethylene (LDPE) film by mutual irradiation technique in the presence of air followed by sulfonation is described. The grafting has been carried out in the presence of air and without any additive. Low dose rate has been seen to facilitate the grafting. Further higher the grafting percentage more is the exchange capacity. The addition of a swelling agent during the sulfonation helped in achieving the high exchange capacity. The TGA-MASS analysis confirmed the grafting and the sulfonation. (author)

  6. Graft Product for Autologous Peripheral Blood Stem Cell Transplantation Enhances Thrombin Generation and Expresses Procoagulant Microparticles and Tissue Factor.

    Science.gov (United States)

    Sidibe, Fatoumata; Spanoudaki, Anastasia; Vanneaux, Valerie; Mbemba, Elisabeth; Larghero, Jerome; Van Dreden, Patrick; Lotz, Jean-Pierre; Elalamy, Ismail; Larsen, Annette K; Gerotziafas, Grigoris T

    2018-05-01

    The beneficial effect of autologous peripheral blood stem cell transplantation (APBSCT) may be compromised by acute vascular complications related to hypercoagulability. We studied the impact of graft product on thrombin generation of normal plasma and the expression of tissue factor (TF) and procoagulant platelet-derived procoagulant microparticles (Pd-MPs) in samples of graft products. Graft products from 10 patients eligible for APBSCT were mixed with platelet-poor plasma (PPP) or platelet-rich plasma (PRP) from healthy volunteers and assessed for in vitro thrombin generation. In control experiments, thrombin generation was assessed in (1) PPP and PRP without any exogenous TF and/or procoagulant phospholipids, (2) PPP with the addition of TF (5 pM) and procoagulant phospholipids (4 μM), (3) in PRP with the addition of TF (5 pM). Graft products were assessed with Western blot assay for TF expression, with a specific clotting assay for TF activity and with flow cytometry assay for Pd-MPs. The graft product enhanced thrombin generation and its procoagulant activity was related to the presence of Pd-MPs and TF. The concentration of Pd-MPs in the graft product was characterized by a significant interindividual variability. The present study reveals the need for a thorough quality control of the graft products regarding their procoagulant potential.

  7. Reconstruction of irradiated mandible after segmental resection of osteoradionecrosis-a technique employing a microvascular latissimus dorsi flap and subsequent particulate iliac bone grafting

    DEFF Research Database (Denmark)

    Hillerup, Soren; Elberg, Jens Jorgen; Thorn, Jens Jorgen

    2014-01-01

    patients had a subsequent bone grafting from the posterior ileum for repair of defects up to 14 cm length. Three patients had no bone graft for various reasons. In three patients dental rehabilitation was achieved with implant supported prosthodontic appliances. Ten patients met the success criteria......, and the defect site was primed with a LD musculocutaneous flap wrapped around the reconstruction plate to bring in vascularized tissue and optimize healing conditions for a subsequent particulate iliac free bone graft reconstruction. The management of defect closure was successful in all 15 patients. Twelve...

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

    International Nuclear Information System (INIS)

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

    1983-01-01

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

  9. USE OF CORTICAL BONE FENESTRATION, AUTOGENOUS FREE SKIN GRAFT, AND THERMOGRAPHY FOR WOUND TREATMENT AND MONITORING IN A RED WOLF (CANIS RUFUS GREGORYI).

    Science.gov (United States)

    Hurley-Sanders, Jennifer L; Sladky, Kurt K; Nolan, Elizabeth C; Loomis, Michael R

    2015-09-01

    A 2-yr-old female red wolf (Canis rufus gregoryi) sustained a degloving injury to the left thoracic limb while in a display habitat. Initial attempts to resolve the extensive wound by using conservative measures were unsuccessful. Subsequent treatment using a free skin graft consisted first of establishment of an adequate granulation bed via cortical bone fenestration. After establishment of a healthy granulation bed was achieved, free skin graft was harvested and transposed over the bed. To monitor viability and incorporation of the graft, serial thermographic imaging was performed. Thermography noninvasively detects radiant heat patterns and can be used to assess vascularization of tissue, potentially allowing early detection of graft failure. In this case, thermography documented successful graft attachment.

  10. Major Vascular Neurocognitive Disorder: A Reappraisal to Vascular Dementia

    Directory of Open Access Journals (Sweden)

    Emre Kumral

    2017-03-01

    Full Text Available Major vascular neurocognitive disorder (NCD is the second leading form of dementia after Alzheimer’s disease, accounting for 17-20% of all dementias. Vascular NCD is a progressive disease caused by reduced cerebral blood flow related to multiple large volume or lacunar infarcts that induce a sudden onset and stepwise decline in cognitive abilities. Despite its prevalence and clinical importance, there is still controversy in the terminology of vascular NCD. Only after the release of Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5 (2013 did the American Psychiatric Association define vascular dementia as “major vascular NCD”. This review includes an overview of risk factors, pathophysiology, types, diagnostic and clinical features of major vascular NCD, and current treatment options of vascular NCD regarding to DSM-5 criteria

  11. Studies on radiation-induced graft polymerization

    International Nuclear Information System (INIS)

    Omichi, Hideki

    1978-09-01

    Radiation-induced graft polymerization is used extensively to improve physical properties of polymers, but few processes are now commercialized. The reason for this is partly inadequate basic research on the reaction and partly the difficulty in developing the grafting process with large radiation source. Firstly, new techniques are proposed of studying kinetics of the graft polymerization in heterogeneous system. Based on the grafting yield, the molecular weight of graft chains, and the amount of radicals given by ESR and activation analysis, kinetic parameters are obtained and the reaction mechanism of grafting process is discussed. Secondly, the development of grafting process of poly (vinyl chloride)-butadiene is described. By study of the reaction, process design, construction and operation of the pilot plant, and economic analysis of the process, this process with 60 Co gamma ray sources is shown to be industrially promising. (author)

  12. Dynamics of bone graft healing around implants

    Directory of Open Access Journals (Sweden)

    Narayan Venkataraman

    2015-01-01

    A few questions arise pertaining to the use of bone grafts along with implants are whether these are successful in approximation with implant. Do they accelerate bone regeneration? Are all defects ultimately regenerated with new viable bone? Is the bone graft completely resorbed or integrated in new bone? Does the implant surface characteristic positively affect osseointegration when used with a bone graft? What type of graft and implant surface can be used that will have a positive effect on the healing type and time? Finally, what are the dynamics of bone graft healing around an implant? This review discusses the cellular and molecular mechanisms of bone graft healing in general and in vicinity of another foreign, avascular body, namely the implant surface, and further, the role of bone grafts in osseointegration and/or clinical success of the implants.

  13. [The Carboclip, a new, atraumatic vascular access for hemodialysis].

    Science.gov (United States)

    Bonnaud, P; Jehenne, G; Man, N K

    1994-01-01

    The Carboclip is a no-needle vascular access device made of an inverted Titanium body. The horizontal bar of 6 mm inner diameter is connected with artery and vein via a vascular graft. The vertical body houses an elastic plug in which is inserted a double canula diving in the blood stream for extracorporeal blood circulation (EBC). The body is wrapped by a flange made of microporous biocarbon in which the subcutaneous fibroblast will growth, forming an antimicrobial barrier and fixing the port to the skin. We report our experience on 30 devices implanted in 30 sheep with 26 extracorporeal circulation simulating hemodialysis. The results demonstrate good tightness of the plug as well at rest as during EBC procedure, sufficient blood flow rate of about 400 ml/min, and benefits of the microporous carbon flange.

  14. Electrospun silk fibroin/poly (L-lactide-ε-caplacton) graft with platelet-rich growth factor for inducing smooth muscle cell growth and infiltration.

    Science.gov (United States)

    Yin, Anlin; Bowlin, Gary L; Luo, Rifang; Zhang, Xingdong; Wang, Yunbing; Mo, Xiumei

    2016-12-01

    The construction of a smooth muscle layer for blood vessel through electrospinning method plays a key role in vascular tissue engineering. However, smooth muscle cells (SMCs) penetration into the electrospun graft to form a smooth muscle layer is limited due to the dense packing of fibers and lack of inducing factors. In this paper, silk fibroin/poly (L-lactide-ε-caplacton) (SF/PLLA-CL) vascular graft loaded with platelet-rich growth factor (PRGF) was fabricated by electrospinning. The in vitro results showed that SMCs cultured in the graft grew fast, and the incorporation of PRGF could induce deeper SMCs infiltrating compared to the SF/PLLA-CL graft alone. Mechanical properties measurement showed that PRGF-incorporated graft had proper tensile stress, suture retention strength, burst pressure and compliance which could match the demand of native blood vessel. The success in the fabrication of PRGF-incorporated SF/PLLA-CL graft to induce fast SMCs growth and their strong penetration into graft has important application for tissue-engineered blood vessels.

  15. Plant Vascular Biology 2010

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Biao

    2014-11-17

    This grant supported the Second International Conference on Plant Vascular Biology (PVB 2010) held July 24-28, 2010 on the campus of Ohio State University, Columbus, Ohio. Biao Ding (Ohio State University; OSU) and David Hannapel (Iowa State University; ISU) served as co-chairs of this conference. Biao Ding served as the local organizer. PVB is defined broadly here to include studies on the biogenesis, structure and function of transport systems in plants, under conditions of normal plant growth and development as well as of plant interactions with pathogens. The transport systems cover broadly the xylem, phloem, plasmodesmata and vascular cell membranes. The PVB concept has emerged in recent years to emphasize the integrative nature of the transport systems and approaches to investigate them.

  16. Vascular cognitive impairment

    Directory of Open Access Journals (Sweden)

    N.V. Vakhnina

    2014-01-01

    Full Text Available Vascular pathology of the brain is the second most common cause of cognitive impairment after Alzheimer's disease. The article describes the modern concepts of etiology, pathogenetic mechanisms, clinical features and approaches to diagnosis and therapy of vascular cognitive impairment (VCI. Cerebrovascular accident, chronic cerebral circulatory insufficiency and their combination, sometimes in combination with a concomitant neurodegenerative process, are shown to be the major types of brain lesions leading to VCI. The clinical presentation of VCI is characterized by the neuropsychological status dominated by impairment of the executive frontal functions (planning, control, attention in combination with focal neurological symptoms. The diagnosis is based on comparing of the revealed neuropsychological and neurological features with neuroimaging data. Neurometabolic, acetylcholinergic, glutamatergic, and other vasoactive drugs and non-pharmacological methods are widely used to treat VCI. 

  17. Vascular Surgery and Robotics

    Directory of Open Access Journals (Sweden)

    Indrani Sen

    2016-01-01

    Full Text Available The application of robotics to Vascular surgery has not progressed as rapidly as of endovascular technology, but this is changing with the amalgamation of these two fields. The advent of Endovascular robotics is an exciting field which overcomes many of the limitations of endovascular therapy like vessel tortuosity and operator fatigue. This has much clinical appeal for the surgeon and hold significant promise of better patient outcomes. As with most newer technological advances, it is still limited by cost and availability. However, this field has seen some rapid progress in the last decade with the technology moving into the clinical realm. This review details the development of robotics, applications, outcomes, advantages, disadvantages and current advances focussing on Vascular and Endovascular robotics

  18. Vascular lesions following radiation

    International Nuclear Information System (INIS)

    Fajardo, L.F.; Berthrong, M.

    1988-01-01

    The special radiation sensitivity of the vascular system is mainly linked to that of endothelial cells, which are perhaps the most radiation-vulnerable elements of mesenchymal tissues. Within the vascular tree, radiation injures most often capillaries, sinusoids, and small arteries, in that order. Lesions of veins are observed less often, but in certain tissues the veins are regularly damaged (e.g., intestine) or are the most affected structures (i.e., liver). Large arteries do suffer the least; however, when significant damage does occur in an elastic artery (e.g., thrombosis or rupture), it tends to be clinically significant and even fatal. Although not always demonstrable in human tissues, radiation vasculopathy generally is dose and time dependent. Like other radiation-induced lesions, the morphology in the vessels is not specific, but it is characteristic enough to be often recognizable. Vascular injury, especially by therapeutic radiation is not just a morphologic marker. It is a mediator of tissue damage; perhaps the most consistent pathogenetic mechanism in delayed radiation injury

  19. Vascular lumen formation.

    Science.gov (United States)

    Lammert, Eckhard; Axnick, Jennifer

    2012-04-01

    The vascular system developed early in evolution. It is required in large multicellular organisms for the transport of nutrients, oxygen, and waste products to and from tissues. The vascular system is composed of hollow tubes, which have a high level of complexity in vertebrates. Vasculogenesis describes the de novo formation of blood vessels, e.g., aorta formation in vertebrate embryogenesis. In contrast, angiogenesis is the formation of blood vessels from preexisting ones, e.g., sprouting of intersomitic blood vessels from the aorta. Importantly, the lumen of all blood vessels in vertebrates is lined and formed by endothelial cells. In both vasculogenesis and angiogenesis, lumen formation takes place in a cord of endothelial cells. It involves a complex molecular mechanism composed of endothelial cell repulsion at the cell-cell contacts within the endothelial cell cords, junctional rearrangement, and endothelial cell shape change. As the vascular system also participates in the course of many diseases, such as cancer, stroke, and myocardial infarction, it is important to understand and make use of the molecular mechanisms of blood vessel formation to better understand and manipulate the pathomechanisms involved.

  20. Pulmonary vascular imaging

    International Nuclear Information System (INIS)

    Fedullo, P.F.; Shure, D.

    1987-01-01

    A wide range of pulmonary vascular imaging techniques are available for the diagnostic evaluation of patients with suspected pulmonary vascular disease. The characteristics of any ideal technique would include high sensitivity and specificity, safety, simplicity, and sequential applicability. To date, no single technique meets these ideal characteristics. Conventional pulmonary angiography remains the gold standard for the diagnosis of acute thromboembolic disease despite the introduction of newer techniques such as digital subtraction angiography and magnetic resonance imaging. Improved noninvasive lower extremity venous testing methods, particularly impedance plethysmography, and ventilation-perfusion scanning can play significant roles in the noninvasive diagnosis of acute pulmonary emboli when properly applied. Ventilation-perfusion scanning may also be useful as a screening test to differentiate possible primary pulmonary hypertension from chronic thromboembolic pulmonary hypertension. And, finally, angioscopy may be a useful adjunctive technique to detect chronic thromboembolic disease and determine operability. Optimal clinical decision-making, however, will continue to require the proper interpretation of adjunctive information obtained from the less-invasive techniques, applied with an understanding of the natural history of the various forms of pulmonary vascular disease and with a knowledge of the capabilities and shortcomings of the individual techniques

  1. Obturator or "lateral" bypass in the management of infected vascular prostheses at the groin

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    Davidović Lazar B.

    2002-01-01

    Full Text Available The infection of the previously implanted vascular graft at the groin, is associated with great mortality and morbidity rate [1]. The authors present a retrospective study in which they analyzed management of infected vascular prostheses at the groin, using obturator bypass in 26 cases, and "lateral" bypass in 15 cases. The indications for obturator bypass reconstructions included: 20 infections of aorto-femoral grafts, two infected pse udoaneurysms in the groin after RTA of the superficial femoral artery, and 4 infections of iliac-femoral grafts. The indications for lateral bypass reconstructions were: infections after aorto-femoral reconstructions - 8 cases; infection after femora-popliteal reconstructions - 4 cases; infection after iliac-femoral reconstruction - 2 patients, and one infected pseudoaneurysm in the groin after RTA of the superficial femoral artery. In 3 subjects obturator bypass was performed using extraperitoneal approach while in other 23 patients transperitoneal approach was done by donor's artery. The obturator bypass was performed using a PTFE graft in 3 cases and Dacron graft in 23. The donor's artery used for obturator bypass was a noninfected proximal part of aortofemoral graft in 20 cases, and iliac artery in 6 patients. The superfical femoral artery was recipient artery for obturator bypass in 3 cases, deep femoral artery in one case, and above the knee popliteal artery in 22 cases (Figure 1. In two patients transperitoenal approach to donors artery for "lateral" bypass has been used, and in 13 cases extraperitoneal. The proximal noninfected part of aorto femoral graft was used as a donor's artery for lateral bypass in 8 patients, while common iliac artery in 7 subjects. In 5 cases recon structions were performed using PTFE grafts, in 3 using autologous saphenous vein grafts, and in 7 using Dacron grafts. The recipient artery for "lateral" bypass was deep femoral in 8 cases, superficial femoral in three patients and

  2. Vascular injuries of the upper extremity Lesões vasculares de membros superiores

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    Raafat Shalabi

    2006-12-01

    Full Text Available OBJECTIVE: This study analyzes the causes of injuries, presentations, surgical approaches, outcome and complications of vascular trauma of the upper limbs, in spite of limited hospital resources. METHODS: A 5-year retrospective analysis. From 01/01/2001 to 31/12/2005, 165 patients were operated for vascular injuries at King Fahd Hospital, Medina, Saudi Arabia. Of all peripheral vascular trauma patients (115, upper limb trauma was present in 58. Diagnosis was made by physical examination and hand-held Doppler alone or in combination with Doppler scan/angiography. Primary vascular repair was performed whenever possible; otherwise, the interposition vein graft was used. Fasciotomy was considered when required. Patients with unsalvageable lower extremity injury requiring primary amputation were excluded from the study. RESULTS: Fifty patients were male (86% and eight were female (14%, aged between 2.5-55 years (mean 23 years. Mean duration of presentation was 8 h after the injury. The most common etiological factor was road traffic accidents, accounting for 50.5% in the blunt trauma group and 33% among all penetrating and stab wound injuries. Incidence of concomitant orthopedic injuries was very high in our study (51%. The brachial artery was the most affected (51%. Interposition vein grafts were used in 53% of the cases. Limb salvage rate was 100%. CONCLUSION: Patients who suffer vascular injuries of the upper extremities should be transferred to vascular surgery centers as soon as possible. Decisive management of peripheral vascular trauma will maximize patient survival and limb salvage. Priorities must be established in the management of associated injuries, and delay must be avoided when ischemic changes are present.OBJETIVO: Este estudo analisa as causas de lesões, apresentação, abordagens cirúrgicas, desfechos e complicações do trauma vascular de membros superiores, apesar de recursos hospitalares limitados. MÉTODOS: An

  3. Repair of Tympanic Membrane Perforations with Customized Bioprinted Ear Grafts Using Chinchilla Models.

    Science.gov (United States)

    Kuo, Che-Ying; Wilson, Emmanuel; Fuson, Andrew; Gandhi, Nidhi; Monfaredi, Reza; Jenkins, Audrey; Romero, Maria; Santoro, Marco; Fisher, John P; Cleary, Kevin; Reilly, Brian

    2018-03-01

    The goal of this work is to develop an innovative method that combines bioprinting and endoscopic imaging to repair tympanic membrane perforations (TMPs). TMPs are a serious health issue because they can lead to both conductive hearing loss and repeated otitis media. TMPs occur in 3-5% of cases after ear tube placement, as well as in cases of acute otitis media (the second most common infection in pediatrics), chronic otitis media with or without cholesteatoma, or as a result of barotrauma to the ear. About 55,000 tympanoplasties, the surgery performed to reconstruct TMPs, are performed every year, and the commonly used cartilage grafting technique has a success rate between 43% and 100%. This wide variability in successful tympanoplasty indicates that the current approach relies heavily on the skill of the surgeon to carve the shield graft into the shape of the TMP, which can be extremely difficult because of the perforation's irregular shape. To this end, we hypothesized that patient specific acellular grafts can be bioprinted to repair TMPs. In vitro data demonstrated that our approach resulted in excellent wound healing responses (e.g., cell invasion and proliferations) using our bioprinted gelatin methacrylate constructs. Based on these results, we then bioprinted customized acellular grafts to treat TMP based on endoscopic imaging of the perforation and demonstrated improved TMP healing in a chinchilla study. These ear graft techniques could transform clinical practice by eliminating the need for hand-carved grafts. To our knowledge, this is the first proof of concept of using bioprinting and endoscopic imaging to fabricate customized grafts to treat tissue perforations. This technology could be transferred to other medical pathologies and be used to rapidly scan internal organs such as intestines for microperforations, brain covering (Dura mater) for determination of sites of potential cerebrospinal fluid leaks, and vascular systems to determine arterial

  4. Septal graft in laryngeal reconstruction

    International Nuclear Information System (INIS)

    Bahannan, Abdulrahman; Slavicek, A.; Taudy, M.; Chovanec, M.

    2006-01-01

    A 62-year-old woman presented with symptoms of dyspnea. Ultrasonography and computed tomography examinations revealed mass extending from the cricoid cartilage to the left lobe of thyroid gland and thyroid cartilage. Cytology revealed possibility of cartilaginous origin, which was proven to be chondrosarcoma (Grade 1) from the biopsy specimen obtained during panendosopy. She underwent one stage radical resection and immediate reconstruction of laryngeal skeleton defect by mucocartilaginous graft from the nasal septum. Her postoperative course was optimal with preservation of the laryngeal functions. Twenty-eight months postoperatively, she had to undergo total laryngectomy as a salvage procedure for the advanced local recurrence. We report on the relatively easy technique for functional reconstruction of the large laryngeal defect with the employment cartilage graft from the nasal septum. (author)

  5. Determining the degree of grafting for poly (vinylidene fluoride) graft-copolymers using fluorine elemental analysis

    International Nuclear Information System (INIS)

    Yu Yang; Zhang Bowu; Yang Xuanxuan; Deng Bo; Li Linfan; Yu Ming; Li Jingye

    2011-01-01

    Acrylic acid (AAc) and styrene (St) were grafted onto poly (vinylidene fluoride) (PVDF) powder or membrane samples by pre-irradiation graft copolymerization. The grafted chains were proved by FT-IR spectroscopy analysis. The degree of grafting (DG) of the grafted PVDF was determined by fluorine elemental analysis (FEA) method, and was compared with the DGs determined by weighing method, acid-base back titration method and quantitative FT-IR method. The results show that the FEA method is accurate, convenient and universal, especially for the grafted polymer powders. (authors)

  6. [Autologous fat grafting in children].

    Science.gov (United States)

    Baptista, C; Bertrand, B; Philandrianos, C; Degardin, N; Casanova, D

    2016-10-01

    Lipofilling or fat grafting transfer is defined as a technique of filling soft tissue by autologous fat grafting. The basic principle of lipofilling is based on a harvest of adipose tissue, followed by a reinjection after treatment. Lipofilling main objective is a volume defect filling, but also improving cutaneous trophicity. Lipofilling specificities among children is mainly based on these indications. Complications of autologous fat grafting among children are the same as those in adults: we distinguish short-term complications (intraoperative and perioperative) and the medium and long-term complications. The harvesting of fat tissue is the main limiting factor of the technique, due to low percentage of body fat of children. Indications of lipofilling among children may be specific or similar to those in adults. There are two types of indications: cosmetic, in which the aim of lipofilling is correcting a defect density, acquired (iatrogenic, post-traumatic scar) or malformation (otomandibular dysplasia, craniosynostosis, Parry Romberg syndrom, Poland syndrom, pectus excavatum…). The aim of functional indications is correcting a velar insufficiency or lagophthalmos. In the paediatric sector, lipofilling has become an alternative to the conventional techniques, by its reliability, safety, reproducibility, and good results. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  7. Assessment of Novel Anti-thrombotic Fusion Proteins for Inhibition of Stenosis in a Porcine Model of Arteriovenous Graft.

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    Christi M Terry

    Full Text Available Hemodialysis arteriovenous synthetic grafts (AVG provide high volumetric blood flow rates shortly after surgical placement. However, stenosis often develops at the vein-graft anastomosis contributing to thrombosis and early graft failure. Two novel fusion proteins, ANV-6L15 and TAP-ANV, inhibit the tissue factor/factor VIIa coagulation complex and the factor Xa/factor Va complex, respectively. Each inhibitor domain is fused to an annexin V domain that targets the inhibitor activity to sites of vascular injury to locally inhibit thrombosis. This study's objective was to determine if these antithrombotic proteins are safe and effective in inhibiting AVG stenosis.A bolus of either TAP-ANV or ANV-6L15 fusion protein was administered intravenously immediately prior to surgical placement of a synthetic graft between the external jugular vein and common carotid artery in a porcine model. At surgery, the vein and artery were irrigated with the anti-thrombotic fusion protein. Control animals received intravenous heparin. At 4 weeks, MRI was performed to evaluate graft patency, the pigs were then euthanized and grafts and attached vessels were explanted for histomorphometric assessment of neointimal hyperplasia at the vein-graft anastomosis. Blood was collected at surgery, immediately after surgery and at euthanasia for serum metabolic panels and coagulation chemistries.No acute thrombosis occurred in the control group or in either experimental group. No abnormal serum chemistries, activated clotting times or PT, PTT values were observed after treatment in experimental or control animals. However, at the vein-graft anastomosis, there was no difference between the control and experimental groups in cross-sectional lumen areas, as measured on MRI, and no difference in hyperplasia areas as determined by histomorphometry. These results suggest that local irrigation of TAP-ANV or ANV-6L15 intra-operatively was as effective in inhibiting acute graft thrombosis

  8. Potential advantages of treatment of transplanted saphenous vein aorto-coronary artery bypass grafts with beta irradiation to prevent graft occlusion.

    Science.gov (United States)

    Smith, R G

    1997-01-01

    Intimal proliferation or Neointimal hyperplasia (NIH) is a vascular lesion that often arises in arteries after balloon angioplasty or other vessel wall injuries. FIH is a vascular lesion that develops in autologous saphenous vein grafts (SVG) after transplantation into the aorto-coronary circulation or the peripheral vascular circulation. FIH shares elements of smooth muscle migration, proliferation and fibrous tissue deposition in common with nibrointimal proliferation (NIH). Either NIH of a coronary artery or FIH of a SVG obstruct the vascular lumen and result in myocardial dysfunction. Local radiotherapy has been used for several decades to reduce the post-operative recurrence of the fibrovascular proliferations of pterygia and keloids. Similarly, in animal and human experiments, endovascular radiotherapy has been shown to reduce arterial smooth muscle proliferation. Consideration of the similarities of vascular smooth muscle cell proliferation in NIH and FIH leads one to suggest that endovascular beta irradiation can reduce FIH as well as it reduces NIH. The goal of such treatment is to achieve a clinically significant decrease in the morbidity and mortality resulting from SVG occlusions. The potential for large reduction of the consequences of SVG occlusion, the very large number of patients at risk, and the simplicity of the proposed intervention encourages prompt scientific evaluation of this technique.

  9. Loss of Renal Allografts Secondary to Candida Vascular Complications in Two Recipients from the Same Donor

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    Govardhana Rao Yannam

    2012-01-01

    Full Text Available Infections remain a major cause of morbidity and mortality in transplant patients. Organ recipients are also susceptible to donor-derived pathogens and the majority of donor infections are easily treatable. Rarely, some pathogens have produced life-threatening complications by compromising the vascular anastomosis. In this case series we report loss of two kidney allografts secondary to vascular complications due to Candida albicans. Both recipients received grafts from a common donor, in whom Candida bacteremia in the donor was not apparent at the time of organ acceptance but became apparent on delayed cultures.

  10. A 10-year institutional experience with open branched graft reconstruction of aortic aneurysms in connective tissue disorders versus degenerative disease.

    Science.gov (United States)

    Hicks, Caitlin W; Lue, Jennifer; Glebova, Natalia O; Ehlert, Bryan A; Black, James H

    2017-11-01

    .25 preoperatively; P = .22). CTD patients with aortic aneurysms who undergo open branched graft reconstruction have reasonable outcomes compared with patients with degenerative pathology, including better branched graft patency and a similar risk of perioperative mortality and complications. Open repair of aortic aneurysms with branched graft reconstruction can be performed safely in both populations with low perioperative mortality, but ongoing surveillance is critical for the detection of new aneurysms, especially among patients with CTD. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  11. Bypass grafting to the anterior tibial artery.

    Science.gov (United States)

    Armour, R H

    1976-01-01

    Four patients with severe ischaemia of a leg due to atherosclerotic occlusion of the tibial and peroneal arteries had reversed long saphenous vein grafts to the patent lower part of the anterior tibial artery. Two of these grafts continue to function 19 and 24 months after operation respectively. One graft failed on the fifth postoperative day and another occluded 4 months after operation. The literature on femorotibial grafting has been reviewed. The early failure rate of distal grafting is higher than in the case of femoropopliteal bypass, but a number of otherwise doomed limbs can be salvaged. Contrary to widely held views, grafting to the anterior tibial artery appears to give results comparable to those obtained when the lower anastomosis is made to the posterior tibial artery.

  12. Anterior Cranial Base Reconstruction with a Reverse Temporalis Muscle Flap and Calvarial Bone Graft

    Directory of Open Access Journals (Sweden)

    Seung Gee Kwon

    2012-07-01

    Full Text Available BackgroundCranial base defects are challenging to reconstruct without serious complications. Although free tissue transfer has been used widely and efficiently, it still has the limitation of requiring a long operation time along with the burden of microanastomosis and donor site morbidity. We propose using a reverse temporalis muscle flap and calvarial bone graft as an alternative option to a free flap for anterior cranial base reconstruction.MethodsBetween April 2009 and February 2012, cranial base reconstructions using an autologous calvarial split bone graft combined with a reverse temporalis muscle flap were performed in five patients. Medical records were retrospectively analyzed and postoperative computed tomography scans, magnetic resonance imaging, and angiography findings were examined to evaluate graft survival and flap viability.ResultsThe mean follow-up period was 11.8 months and the mean operation time for reconstruction was 8.4±3.36 hours. The defects involved the anterior cranial base, including the orbital roof and the frontal and ethmoidal sinus. All reconstructions were successful. Viable flap vascularity and bone survival were observed. There were no serious complications except for acceptable donor site depressions, which were easily corrected with minor procedures.ConclusionsThe reverse temporalis muscle flap could provide sufficient bulkiness to fill dead space and sufficient vascularity to endure infection. The calvarial bone graft provides a rigid framework, which is critical for maintaining the cranial base structure. Combined anterior cranial base reconstruction with a reverse temporalis muscle flap and calvarial bone graft could be a viable alternative to free tissue transfer.

  13. Metallic stent placement in hemodialysis graft patients after insufficient balloon dilation

    International Nuclear Information System (INIS)

    Liang, Huei-Lung; Pan, Huay-Ben; Lin, Yih-Huie; Chen, Chiung-Yu; Lai, Pin-Hong; Yang, Chien-Fang; Chung, Hsiao-Min; Wu, Tung-Ho; Chou, Kang-Ju

    2006-01-01

    We wanted to report our experience of metallic stent placement after insufficient balloon dilation in graft hemodialysis patients. Twenty-three patients (13 loop grafts in the forearm and 10 straight grafts in the upper arm) underwent metallic stent placement due to insufficient flow after urokinase thrombolysis and balloon dilation. The indications for metallic stent deployment included 1) recoil and/or kinked venous stenosis in 21 patents (venous anastomosis: 17 patients, peripheral outflow vein: four patients); and 2) major vascular rupture in two patients. Metallic stents 8-10mm in diameter and 40-80 mm in length were used. Of them, eight stents were deployed across the elbow crease. Access patency was determined by clinical follow-up and the overall rates were calculated by Kaplan-Meier survival analysis. No procedure-related complications (stent fracture or central migration) were encountered except for a delayed Wallstent shortening/migration at the venous anastomosis, which resulted in early access failure. The overall primary and secondary patency rates (±standard error) of all the vascular accesses in our 23 patients at 3, 6, 12 and 24 months were 69%±9 and 88%±6,41% ±10 and 88%±6, 30%±10 and 77%±10, and 12%±8 and 61%±13, respectively. For the forearm and upper-arm grafts, the primary and secondary patency rates were 51%±16 and 86%±13 vs 45%±15 and 73%±13 at 6 months, and 25%±15 and 71%±17 vs 23%±17 and 73%±13 at 12 months (ρ = .436 and .224), respectively. Metallic stent placement is a safe and effective means for treating peripheral venous lesions in dialysis graft patients after insufficient balloon dilation. No statistically difference in the patency rates between the forearm and upper-arm patient groups was seen

  14. Vascular remodeling and mineralocorticoids.

    Science.gov (United States)

    Weber, K T; Sun, Y; Campbell, S E; Slight, S H; Ganjam, V K

    1995-01-01

    Circulating mineralocorticoid hormones are so named because of their important homeostatic properties that regulate salt and water balance via their action on epithelial cells. A broader range of functions in nonclassic target cellular sites has been proposed for these steroids and includes their contribution to wound healing following injury. A chronic, inappropriate (relative to intravascular volume and dietary sodium intake) elevation of these circulating hormones evokes a wound healing response in the absence of tissue injury--a wound healing response gone awry. The adverse remodeling of vascularized tissues seen in association with chronic mineralocorticoid excess is the focus of this review.

  15. Evaluation of early coronary graft patency after coronary artery bypass graft surgery using multislice computed tomography angiography

    Directory of Open Access Journals (Sweden)

    Raissi Kamal

    2009-12-01

    Full Text Available Abstract Background Coronary artery bypass graft (CABG surgery is the standard of care in the treatment of advanced coronary artery disease, and its long-term results are affected by the failure of bypass grafts. The aim of the present study was to evaluate the early patency rate in coronary bypass grafts. Methods A total of 107 consecutive patients who underwent CABG were included in this study. Early graft patency was evaluated via computed tomography (CT angiography in the first week after surgery. Results There were a total of 366 grafts, comprised of 250 venous grafts and 116 arterial grafts. Multi-slice CT detected acute graft occlusions in 32 (8.7% of all the grafts, including 26 (10% of the 250 venous grafts and 6 (5% of the 116 arterial grafts. The patency rates obtained were 97.3% for the left internal mammary (IMA grafts, 50% for the radial artery grafts, and 50% for the right IMA grafts. Additionally, 107 (96.4% grafts to the left anterior descending artery (LAD were classified as patent, whereas 1 (30% of the 3 grafts in the left circumflex (LCX region and 1 (50% of the 2 grafts in the right coronary artery (RCA territory were found to be occluded. In the venous category, 8 (13.7% of the 58 grafts to LAD were found to be occluded. In the LCX region, 9 (8.5% of the 106 grafts were classified as occluded, while the remaining 97 (91.5% grafts were patent. The venous grafts to RCA were occluded in 9 (10.4% of the 86 grafts. Amongst the multiple preoperative, intraoperative, and postoperative factors, pump time was significantly longer in the patients with occluded grafts than in those with patent grafts (P = 0.04. Conclusion The IMA grafts had the highest early patency rate amongst the coronary bypass grafts. However, the other arterial grafts were associated with a high rate of acute occlusions.

  16. 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.

  17. Current status of grafts and implants in rhinoplasty: Part II. Homologous grafts and allogenic implants.

    Science.gov (United States)

    Sajjadian, Ali; Naghshineh, Nima; Rubinstein, Roee

    2010-03-01

    After reading this article, the participant should be able to: 1. Understand the challenges in restoring volume and structural integrity in rhinoplasty. 2. Identify the appropriate uses of various homologous grafts and allogenic implants in reconstruction, including: (a) freeze-dried acellular allogenic cadaveric dermis grafts, (b) irradiated cartilage grafts, (c) hydroxyapatite mineral matrix, (d) silicone implants, (e) high-density polyethylene implants, (f) polytetrafluoroethylene implants, and (g) injectable filler materials. 3. Identify the advantages and disadvantages of each of these biomaterials. 4. Understand the specific techniques that may aid in the use these grafts or implants. This review specifically addresses the use of homologous grafts and allogenic implants in rhinoplasty. It is important to stress that autologous materials remain the preferred graft material for use in rhinoplasty, owing to their high biocompatibility and low risk of infection and extrusion. However, concerns of donor-site morbidity, graft availability, and graft resorption have motivated the development and use of homologous and allogenic implants.

  18. Multiple arterial grafts in coronary artery bypass grafting, Sohag University Hospital's initial experience

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    A.A.A. Elsayed

    2017-12-01

    Conclusions: Using multiple arterial grafts did not add a significant risk or time to the classic CABG. With accumulating evidence about better patency rate in arterial grafts, MAR is recommended especially in younger patients undergoing CABG.

  19. Usefulness of magnetic resonance angiography in diagnosis of peripheral vascular disease

    International Nuclear Information System (INIS)

    Kuga, Takayuki; Akiyama, Norio; Takenaka, Hiroaki; Fujioka, Kentaro; Zempo, Noriya; Esato, Kensuke

    1992-01-01

    The diagnostic usefulness of magnetic resonance angiography (MRA) was evaluated in 19 patients with peripheral vascular disease. It takes thirty minutes or less to perform this test, without any complications. The percent of correct diagnosis on obstructive and stenotic region was 75% in cases of deep vein thrombosis. In addition, it was easy to diagnose an existence of a graft patent. However, it was unsatisfactory to understand morphologic changes of an iliac artery and to determine the position of grafting. The position and size of dilatation and existence of thrombus were easily evaluated in patients with venous aneurysm and varicose vein. MRA was a non-invasive, short spending time imaging. It was available for pregnant women and people with drug allergy, heart failure or renal failure. We believe that MRA can be used in the preoperative examination and the evaluation of the postoperative complications in the peripheral vascular diseases. (J.P.N.)

  20. Repair of a mandibular defect with a free vascularized coccygeal vertebra transfer in a dog.

    Science.gov (United States)

    Yeh, L S; Hou, S M

    1994-01-01

    Bilateral mandibular defects in a male mongrel dog were repaired. On the left side, a free vascularized coccygeal bone graft that included the median caudal artery and caudal vein was used to correct the defect. On the right side, the defect was bridged with a bone plate and screws. For further immobilization, the muzzle was temporarily taped for 3 weeks and a pharyngostomy tube was used for nutritional support. The dog was able to eat dry commercial food satisfactorily within 2 months of surgery despite mild malocclusion. Radiographs taken 2 months and 18 months postoperatively showed bony union with graft hypertrophy in the left mandible, whereas the right mandibular defect showed protracted nonunion. The results indicate that vascularized coccygeal vertebra transfer provides an alternative for the management of canine mandibular defects.

  1. Usefulness of magnetic resonance angiography in diagnosis of peripheral vascular disease

    Energy Technology Data Exchange (ETDEWEB)

    Kuga, Takayuki; Akiyama, Norio; Takenaka, Hiroaki; Fujioka, Kentaro; Zempo, Noriya; Esato, Kensuke (Yamaguchi Univ., Ube (Japan). School of Medicine)

    1992-03-01

    The diagnostic usefulness of magnetic resonance angiography (MRA) was evaluated in 19 patients with peripheral vascular disease. It takes thirty minutes or less to perform this test, without any complications. The percent of correct diagnosis on obstructive and stenotic region was 75% in cases of deep vein thrombosis. In addition, it was easy to diagnose an existence of a graft patent. However, it was unsatisfactory to understand morphologic changes of an iliac artery and to determine the position of grafting. The position and size of dilatation and existence of thrombus were easily evaluated in patients with venous aneurysm and varicose vein. MRA was a non-invasive, short spending time imaging. It was available for pregnant women and people with drug allergy, heart failure or renal failure. We believe that MRA can be used in the preoperative examination and the evaluation of the postoperative complications in the peripheral vascular diseases. (J.P.N.).

  2. Composite vascular scaffold combining electrospun fibers and physically-crosslinked hydrogel with copper wire-induced grooves structure.

    Science.gov (United States)

    Liu, Yuanyuan; Jiang, Chen; Li, Shuai; Hu, Qingxi

    2016-08-01

    While the field of tissue engineered vascular grafts has greatly advanced, many inadequacies still exist. Successfully developed scaffolds require mechanical and structural properties that match native vessels and optimal microenvironments that foster cell integration, adhesion and growth. We have developed a small diameter, three-layered composite vascular scaffold which consists of electrospun fibers and physically-crosslinked hydrogel with copper wire-induced grooves by combining the electrospinning and dip-coating methods. Scaffold morphology and mechanics were assessed, quantified and compared to native vessels. Scaffolds were seeded with Human Umbilical Vein Endothelial Cells (HUVECs), cultured in vitro for 3 days and were evaluated for cell viability and morphology. The results showed that composite scaffolds had adjustable mechanical strength and favorable biocompatibility, which is important in the future clinical application of Tissue-engineered vascular grafts (TEVGs). Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Harvesting the free fibular graft: A modified approach

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    Amitava Narayan Mukherjee

    2011-01-01

    Full Text Available Background: The conventional technique of free non-vascularized fibular grafting is attended with some amount of morbidity and a long scar. We report a technique with little interference to the surrounding soft tissues to harvest more than one-third of whole length fibula. Patients and Methods: Thirty four patients of average age 23.5 years (range 8 to 51 years having various pathologies like simple bone cysts (n=9, fibrous dysplasias (n=6, giant cell tumors (n=7, fracture non-union (n=10 and aneurysmal bone cysts (n=2 were taken up for the study. The fibula were harvested by two separate incisions, 1 cm each at proximal and distal extent of proposed donor site for taking out of graft after elevating the periosteum circumferentially using a periosteum stripper. Compression bandage and above knee plaster immobilization was applied to reduce the dead space collection . Results: The mean followup is 34 months. The patients were evaluated clinicoradiology. Thirty three patients showed good results. One patient had fair result due to delayed wound healing from hematoma which was treated surgically. Conclusion: The approach of harvesting fibula suggested by author reduces donor site morbidity and is safer than conventional approach.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-15

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

  5. Prolonging survival in vascularized bone allograft transplantation: developing specific immune unresponsiveness

    International Nuclear Information System (INIS)

    Paskert, J.P.; Yaremchuk, M.J.; Randolph, M.A.; Weiland, A.J.

    1987-01-01

    Vascularized bone allografts (VBAs) could be useful adjuncts to the clinical reconstructive surgeon's arsenal. These grafts are known experimentally to be subject to host rejection. One way to control the rejection problem would be to develop specific immune unresponsiveness via host conditioning. Using a proven reliable model in inbred rats for studying heterotopic VBA transplantation, recipient animals were conditioned preoperatively with third-party unrelated blood, donor-specific blood (DSB) alone and with cyclosporine, and ultraviolet irradiated donor-specific blood. The combination of DSB plus cyclosporine delayed rejection of grafts across a strong histocompatibility barrier for three to four weeks. However, rejection was delayed across a weak histocompatibility barrier for five to six weeks using this same host pretreatment. The implications are that specific immunosuppression, although possible, is difficult to achieve in VBA transplantation, and that such techniques will rely on tissue-matching to minimize the genetic disparity between graft and host

  6. The autologus graft of epithelial tissue culture

    Directory of Open Access Journals (Sweden)

    Minaee B

    1999-08-01

    Full Text Available With the intention of research about culture and autologus graft of epithelial tissue we used 4 french Albino Rabbits with an average age of 2 months. After reproduction on the support in EMEM (Eagle's Minimum Essential Medium we used this for graft after 4 weeks. This region which grafted total replaced. After fixation of this sample and passing them through various process, histological sections were prepared. These sections were stained with H & E and masson's trichrome and studied by light microscope. We succeeded in graft. We hope in the near future by using the method of epithelium tissue culture improving to treat burned patients.

  7. Nuclear accidents and bone marrow graft

    International Nuclear Information System (INIS)

    Bernard, J.

    1988-01-01

    In case of serious contamination, the only efficacious treatment is the bone marrow grafts. The graft types and conditions have been explained. To restrict the nuclear accidents consequences, it is recommended to: - take osseous medulla of the personnel exposed to radiations and preserve it , that permits to carry out rapidly the auto-graft in case of accidents; - determine, beforehand, the HLA group of the personnel; - to register the voluntary donors names and addresses, and their HLA group, that permits to find easily a compatible donar in case of allo-graft. (author)

  8. Efficacy of linezolid, teicoplanin, and vancomycin in prevention of an experimental polytetrafluoroethylene graft infection model caused by methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Mese, Bulent; Bozoglan, Orhan; Elveren, Serdal; Eroglu, Erdinc; Gul, Mustafa; Celik, Ahmet; Ciralik, Harun; Yildirimdemir, Halil Ibrahim; Yasim, Alptekin

    2015-03-27

    The aim of this study was to evaluate the effectiveness of linezolid, teicoplanin, and vancomycin in prevention of prosthetic vascular graft infections in a vascular graft infection model. Fifty rats were divided into 5 groups. A polytetrafluoroethylene graft was implanted on the back of each rat. Methicillin-resistant Staphylococcus aureus (MRSA) strain was inoculated into all rats except Group 1. Group 2 was not given any treatment, Group 3 received linezolid, Group 4 received vancomycin, and Group 5 received teicoplanin. The grafts were removed for microbiological and histological examinations on the 7th day. In addition, C-reactive protein and prealbumin levels and leukocyte counts in obtained blood specimens were determined. Group 1 did not have infection. Group 2 had bacteria 5.7 × 10(4) CFU/cm(2). Group 3 and Group 4 had less bacterial growth. Group 5 had no bacterial growth. The number of bacteria was significantly higher in Group 2 than in the other experimental groups and the control group (pprevention of prosthetic vascular graft infections.

  9. Interventional vascular radiology

    International Nuclear Information System (INIS)

    Yune, H.Y.

    1984-01-01

    The papers published during this past year in the area of interventional vascular radiology presented some useful modifications and further experiences both in the area of thromboembolic therapy and in dilation and thrombolysis, but no new techniques. As an introductory subject, an excellent monograph reviewing the current spectrum of pharmacoangiography was presented in Radiographics. Although the presented material is primarily in diagnostic application of various pharmacologic agents used today to facilitate demonstration of certain diagnostic criteria of various disease processes, both vasodilatory and vasoconstrictive reaction to these agents are widely used in various therapeutic vascular procedures. This monograph should be reviewed by every angiographer whether or not he or she performs interventional procedures, and it would be very convenient to have this table available in the angiography suite. In a related subject, Bookstein and co-workers have written an excellent review concerning pharmacologic manipulations of various blood coagulative parameters during angiography. Understanding the proper method of manipulation of the bloodclotting factors during angiography, and especially during interventional angiography, is extremely important. Particularly, the method of manipulating the coagulation with the use of heparin and protamine and modification of the platelet activity by using aspirin and dipyridamole are succinctly reviewed. The systemic and selective thrombolytic activities of streptokianse are also discussed

  10. Vascular dysfunction in preeclampsia.

    Science.gov (United States)

    Brennan, Lesley J; Morton, Jude S; Davidge, Sandra T

    2014-01-01

    Preeclampsia is a complex disorder which affects an estimated 5% of all pregnancies worldwide. It is diagnosed by hypertension in the presence of proteinuria after the 20th week of pregnancy and is a prominent cause of maternal morbidity and mortality. As delivery is currently the only known treatment, preeclampsia is also a leading cause of preterm delivery. Preeclampsia is associated with maternal vascular dysfunction, leading to serious cardiovascular risk both during and following pregnancy. Endothelial dysfunction, resulting in increased peripheral resistance, is an integral part of the maternal syndrome. While the cause of preeclampsia remains unknown, placental ischemia resulting from aberrant placentation is a fundamental characteristic of the disorder. Poor placentation is believed to stimulate the release of a number of factors including pro- and antiangiogenic factors and inflammatory activators into the maternal systemic circulation. These factors are critical mediators of vascular function and impact the endothelium in distinctive ways, including enhanced endothelial oxidative stress. The mechanisms of action and the consequences on the maternal vasculature will be discussed in this review. © 2013 John Wiley & Sons Ltd.

  11. Blood vessel replacement: 50 years of development and tissue engineering paradigms in vascular surgery

    Czech Academy of Sciences Publication Activity Database

    Chlupáč, Jaroslav; Filová, Elena; Bačáková, Lucie

    2009-01-01

    Roč. 58, Suppl.2 (2009), S119-S139 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) 1M0510; GA AV ČR(CZ) 1QS500110564 Institutional research plan: CEZ:AV0Z50110509 Keywords : small-caliber vascular grafts * tissue engineering * dynamic bioreactor Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.430, year: 2009

  12. Vascular Remodeling in Experimental Hypertension

    Directory of Open Access Journals (Sweden)

    Norma R. Risler

    2005-01-01

    Full Text Available The basic hemodynamic abnormality in hypertension is an increased peripheral resistance that is due mainly to a decreased vascular lumen derived from structural changes in the small arteries wall, named (as a whole vascular remodeling. The vascular wall is an active, flexible, and integrated organ made up of cellular (endothelial cells, smooth muscle cells, adventitia cells, and fibroblasts and noncellular (extracellular matrix components, which in a dynamic way change shape or number, or reorganize in response to physiological and pathological stimuli, maintaining the integrity of the vessel wall in physiological conditions or participating in the vascular changes in cardiovascular diseases such as hypertension. Research focused on new signaling pathways and molecules that can participate in the mechanisms of vascular remodeling has provided evidence showing that vascular structure is not only affected by blood pressure, but also by mechanisms that are independent of the increased pressure. This review will provide an overview of the evidence, explaining some of the pathophysiologic mechanisms participating in the development of the vascular remodeling, in experimental models of hypertension, with special reference to the findings in spontaneously hypertensive rats as a model of essential hypertension, and in fructose-fed rats as a model of secondary hypertension, in the context of the metabolic syndrome. The understanding of the mechanisms producing the vascular alterations will allow the development of novel pharmacological tools for vascular protection in hypertensive disease.

  13. Vascular pattern formation in plants.

    Science.gov (United States)

    Scarpella, Enrico; Helariutta, Ykä

    2010-01-01

    Reticulate tissue systems exist in most multicellular organisms, and the principles underlying the formation of cellular networks have fascinated philosophers, mathematicians, and biologists for centuries. In particular, the beautiful and varied arrangements of vascular tissues in plants have intrigued mankind since antiquity, yet the organizing signals have remained elusive. Plant vascular tissues form systems of interconnected cell files throughout the plant body. Vascular cells are aligned with one another along continuous lines, and vascular tissues differentiate at reproducible positions within organ environments. However, neither the precise path of vascular differentiation nor the exact geometry of vascular networks is fixed or immutable. Several recent advances converge to reconcile the seemingly conflicting predictability and plasticity of vascular tissue patterns. A control mechanism in which an apical-basal flow of signal establishes a basic coordinate system for body axis formation and vascular strand differentiation, and in which a superimposed level of radial organizing cues elaborates cell patterns, would generate a reproducible tissue configuration in the context of an underlying robust, self-organizing structure, and account for the simultaneous regularity and flexibility of vascular tissue patterns. Copyright 2010 Elsevier Inc. All rights reserved.

  14. Prospective randomized comparison of scar appearances between cograft of acellular dermal matrix with autologous split-thickness skin and autologous split-thickness skin graft alone for full-thickness skin defects of the extremities.

    Science.gov (United States)

    Yi, Ju Won; Kim, Jae Kwang

    2015-03-01

    The purpose of this study was to evaluate the clinical outcomes of cografting of acellular dermal matrix with autologous split-thickness skin and autologous split-thickness skin graft alone for full-thickness skin defects on the extremities. In this prospective randomized study, 19 consecutive patients with full-thickness skin defects on the extremities following trauma underwent grafting using either cograft of acellular dermal matrix with autologous split-thickness skin graft (nine patients, group A) or autologous split-thickness skin graft alone (10 patients, group B) from June of 2011 to December of 2012. The postoperative evaluations included observation of complications (including graft necrosis, graft detachment, or seroma formation) and Vancouver Scar Scale score. No statistically significant difference was found regarding complications, including graft necrosis, graft detachment, or seroma formation. At week 8, significantly lower Vancouver Scar Scale scores for vascularity, pliability, height, and total score were found in group A compared with group B. At week 12, lower scores for pliability and height and total scores were identified in group A compared with group B. For cases with traumatic full-thickness skin defects on the extremities, a statistically significant better result was achieved with cograft of acellular dermal matrix with autologous split-thickness skin graft than with autologous split-thickness skin graft alone in terms of Vancouver Scar Scale score. Therapeutic, II.

  15. Postoperative irradiation after reconstructive surgery: comparative study of radiosensitivity between free-skin grafts and skin flaps

    International Nuclear Information System (INIS)

    Sumi, Y.; Ueda, M.; Kaneda, T.; Oka, T.; Torii, S.; Sakuma, S.

    1984-01-01

    Radiation effects after reconstructive surgery (free-skin grafts and skin flaps) were studied in the rat, and the optimum time for irradiation was determined. The radiosensitivity of both free-skin grafts and skin flaps showed the same trend depending on time of irradiation after operation. The grafts or flaps irradiated in the hypervascular stage showed severe reactions to irradiation, whereas those irradiated in the hypovascular stage showed milder reactions in gross and microangiographic observation. Vascular damage should be given primary consideration when deciding the proper time for irradiation after reconstructive surgery. In general, free-skin grafts showed more severe reactions than skin flaps, especially in the grafts irradiated in the early stage after operation. The experimental results of this study cannot be readily transferred to a clinical setting, but they suggest that postoperative irradiation could be begun 3 to 4 weeks after operation with respect to graft or flap survival, and the results of the clinical cases almost coincide with these experimental results

  16. Target ballon-assisted antegrade and retrograde approach for recanalization of thrombosed fem-pop bypass graft using the outbreak catheter

    International Nuclear Information System (INIS)

    Kwak, Jung Won; Chung, Hwan Hoon; Lee, Seung Hwa; Yeom, Suk Keu; Cha, Sang Hoon

    2016-01-01

    The subintimal arterial flossing with antegrade-retrograde intervention (SAFARI) technique is reportedly effective in severe peripheral vascular disease that cannot be treated with standard endovascular techniques including subintimal angioplasty. In this report, we used a target balloon with the Outback catheter to recanalize a thrombosed bypass graft that could not be treated successfully with SAFARI

  17. Target ballon-assisted antegrade and retrograde approach for recanalization of thrombosed fem-pop bypass graft using the outbreak catheter

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Jung Won; Chung, Hwan Hoon; Lee, Seung Hwa; Yeom, Suk Keu; Cha, Sang Hoon [Dept. of Radiology, Korea University College of Medicine, Ansan Hospital, Ansan (Korea, Republic of)

    2016-01-15

    The subintimal arterial flossing with antegrade-retrograde intervention (SAFARI) technique is reportedly effective in severe peripheral vascular disease that cannot be treated with standard endovascular techniques including subintimal angioplasty. In this report, we used a target balloon with the Outback catheter to recanalize a thrombosed bypass graft that could not be treated successfully with SAFARI.

  18. Fixation methods in mandibular reconstruction using fibula grafts: a comparative study into the relative strength of three different types of osteosynthesis

    NARCIS (Netherlands)

    Strackee, S. D.; Kroon, F. H.; Bos, K. E.

    2001-01-01

    Bone staples made of a nickel titanium alloy exert dynamic compression, require little dissection, and may provide an alternative to conventional fixation in mandibular reconstruction with a free vascularized fibula graft. To evaluate its stability relative to conventional methods of fixation with

  19. Lymphoid Tissue Grafts in Man

    Energy Technology Data Exchange (ETDEWEB)

    Kay, H. E.M. [Royal Marsden Hospital, Institute of Cancer Research, London (United Kingdom)

    1969-07-15

    Grafts of lymphoid tissue or of lymphoid stem cells may be appropriate in the treatment of some congenital immune deficiency disorders. The reasons for preferring tissues of foetal origin are discussed and the evidence for foetal immunocompetence is briefly summarized. Methods of storing foetal liver cells and cells or fragments of thymus are mentioned, and the organization of the Foetal Tissue Bank of the Royal Marsden Hospital is described. Clinical data from transplantation of lymphoid cells in various immune deficiency disorders are briefly presented. (author)

  20. Development of sodium alginate and konkoli gum- grafted ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-05-02

    May 2, 2008 ... grafted-polyacrylamide blend membrane: optimization of grafting conditions .... medium and reduce rate of termination by the coupling of the growing ... Effect of time. The time conversion curve of the graft copolymerization ...

  1. Industrial application of electron beams for grafting and vulcanization

    Energy Technology Data Exchange (ETDEWEB)

    Makuuchi, Keizo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1994-12-31

    The topics discussed are radiation graft polymerization; industrial application of radiation grafting - ion exchange membrane for a battery separator, ammonia adsorbent, non-flammable PE (polyethylene) foam; R and D on radiation grafting, radiation vulcanization of natural rubber.

  2. Industrial application of electron beams for grafting and vulcanization

    International Nuclear Information System (INIS)

    Keizo Makuuchi

    1994-01-01

    The topics discussed are radiation graft polymerization; industrial application of radiation grafting - ion exchange membrane for a battery separator, ammonia adsorbent, non-flammable PE (polyethylene) foam; R and D on radiation grafting, radiation vulcanization of natural rubber

  3. Effect of bidispersity in grafted chain length on grafted chain conformations and potential of mean force between polymer grafted nanoparticles in a homopolymer matrix.

    Science.gov (United States)

    Nair, Nitish; Wentzel, Nathaniel; Jayaraman, Arthi

    2011-05-21

    In efforts to produce polymeric materials with tailored physical properties, significant interest has grown around the ability to control the spatial organization of nanoparticles in polymer nanocomposites. One way to achieve controlled particle arrangement is by grafting the nanoparticle surface with polymers that are compatible with the matrix, thus manipulating the interfacial interactions between the nanoparticles and the polymer matrix. Previous work has shown that the molecular weight of the grafted polymer, both at high grafting density and low grafting density, plays a key role in dictating the effective inter-particle interactions in a polymer matrix. At high grafting density nanoparticles disperse (aggregate) if the graft molecular weight is higher (lower) than the matrix molecular weight. At low grafting density the longer grafts can better shield the nanoparticle surface from direct particle-particle contacts than the shorter grafts and lead to the dispersion of the grafted particles in the matrix. Despite the importance of graft molecular weight, and evidence of non-trivial effects of polydispersity of chains grafted on flat surfaces, most theoretical work on polymer grafted nanoparticles has only focused on monodisperse grafted chains. In this paper, we focus on how bidispersity in grafted chain lengths affects the grafted chain conformations and inter-particle interactions in an implicit solvent and in a dense homopolymer polymer matrix. We first present the effects of bidispersity on grafted chain conformations in a single polymer grafted particle using purely Monte Carlo (MC) simulations. This is followed by calculations of the potential of mean force (PMF) between two grafted particles in a polymer matrix using a self-consistent Polymer Reference Interaction Site Model theory-Monte Carlo simulation approach. Monte Carlo simulations of a single polymer grafted particle in an implicit solvent show that in the bidisperse polymer grafted particles

  4. Improvement of polymer stability by radiation grafting

    International Nuclear Information System (INIS)

    Ranogajec, F.; Mlinac-Misak, M.

    1999-01-01

    Losses of the stabilizer due to extractability or volatility immediately affect ultimate performance of polymer product. A new approach to increase the persistence of the stabilizer in the final product is to chemically bind it to the polymer backbone. Radiation grafting or crosslinking could be an efficient method for this, when the stabilizer is polymerizable. By a mutual gamma irradiation method, photoprotector 2-hydroxy-4-(3-methacryloxy-2- hydroxy-propoxy) benzophenone (HMB) has been readily grafted to low density polyethylene (LDPE) in benzene, tetrahydrofuran and methanol solution, respectively. Surface grafting occurs in a methanol solution of stabilizer, while in benzene and tetrahydrofuran solutions of stabilizer, grafting proceeds more or less in the inner parts of the polymeric film as well. The grafted LDPE film in methanol and tetrahydrofuran (containing 1 w/w % of grafted HMB), 1 w/w % blended HMB with LDPE and nongrafted LDPE film, were all exposed to accelerated aging and natural weathering and their spectral changes, expressed by the carbonyl index, were then compared. The change of elongation at break and tensile strength were measured in the course of aging. UV stability tests on aged films and change in mechanical properties indicate a pronounced protective effect achieved by grafted stabilizer. Grafting in methanol solution appears to be an efficient photostabilization treatment and the most economical with respect to the consumption of monomer, the grafting yield being less than 0.5%. Surface grafting is an efficient photostabilization method since grafted stabilizer is chemically bound to a polymeric surface and in this way the problem of evaporation of blended stabilizers during the prolonged use of polymeric materials is eliminated. (author)

  5. Treatment of early-stage pressure ulcers by using autologous adipose tissue grafts.

    Science.gov (United States)

    Marangi, Giovanni Francesco; Pallara, Tiziano; Cagli, Barbara; Schena, Emiliano; Giurazza, Francesco; Faiella, Elio; Zobel, Bruno Beomonte; Persichetti, Paolo

    2014-01-01

    Assessing pressure ulcers (PUs) in early stages allows patients to receive safer treatment. Up to now, in addition to clinical evaluation, ultrasonography seems to be the most suitable technique to achieve this goal. Several treatments are applied to prevent ulcer progression but none of them is totally effective. Furthermore, the in-depth knowledge of fat regenerative properties has led to a wide use of it. With this study the authors aim at introducing a new approach to cure and prevent the worsening of early-stage PUs by using fat grafts. The authors selected 42 patients who showed clinical and ultrasonographic evidence of early-stage PUs. Values of skin thickness, fascial integrity, and subcutaneous vascularity were recorded both on the PU area and the healthy trochanteric one, used as control region. Fat grafting was performed on all patients. At three months, abnormal ultrasonographic findings, such as reduction of cutaneous and subcutaneous thickness, discontinuous fascia, and decrease in subcutaneous vascularity, all were modified with respect to almost all the corresponding parameters of the control region. Results highlight that the use of fat grafts proved to be an effective treatment for early-stage PUs, especially in the care of neurological and chronic bedridden patients.

  6. Treatment of Early-Stage Pressure Ulcers by Using Autologous Adipose Tissue Grafts

    Directory of Open Access Journals (Sweden)

    Giovanni Francesco Marangi

    2014-01-01

    Full Text Available Assessing pressure ulcers (PUs in early stages allows patients to receive safer treatment. Up to now, in addition to clinical evaluation, ultrasonography seems to be the most suitable technique to achieve this goal. Several treatments are applied to prevent ulcer progression but none of them is totally effective. Furthermore, the in-depth knowledge of fat regenerative properties has led to a wide use of it. With this study the authors aim at introducing a new approach to cure and prevent the worsening of early-stage PUs by using fat grafts. The authors selected 42 patients who showed clinical and ultrasonographic evidence of early-stage PUs. Values of skin thickness, fascial integrity, and subcutaneous vascularity were recorded both on the PU area and the healthy trochanteric one, used as control region. Fat grafting was performed on all patients. At three months, abnormal ultrasonographic findings, such as reduction of cutaneous and subcutaneous thickness, discontinuous fascia, and decrease in subcutaneous vascularity, all were modified with respect to almost all the corresponding parameters of the control region. Results highlight that the use of fat grafts proved to be an effective treatment for early-stage PUs, especially in the care of neurological and chronic bedridden patients.

  7. Photodynamic damage to cartilage and synovial tissue grafted on a chick's chorioallantoic membrane

    Science.gov (United States)

    Fisher, M.; Nahir, A. M.; Kimel, Sol

    1997-09-01

    Rheumatoid arthritis (RA) is a chronic inflammatory disease of the synovial joints causing pain deformities and disability. The highly vascular inflamed synovium has aggressive and destructive characteristics, it invades, erodes and gradually destroys cartilage and underlying bone. Photodynamic therapy (PDT) was performed using the chick chorioallantoic membrane (CAM) model to investigate the vitality of synovium and cartilage implanted on the CAM. Synovium, obtained from human patients, was grafted onto the CAM; gross microscopy and histology proved its vitality 7 days post grafting. Cartilage obtained from rabbit knee joint was also maintained on the CAM for 7 days. Its vitality was demonstrated by histology and by measuring metabolic and enzymatic activity of cartilage cells (chondrocytes) as well as the collagen and proteoglycans content. Selective PDT was performed using aluminum phthalocyanine tetrasulfonate (AlPcS4), a hydrophilic compound, soluble in biological solutions, as a photosensitizer. After irradiation with a diode laser (lambda equals 670 nm, 10 mW) damage was observed in vascularized synovium grafts, whereas avascular cartilage remained intact.

  8. Biodegradability of poly(3-hydroxybutyrate) film grafted with vinyl acetate: Effect of grafting and saponification

    Science.gov (United States)

    Wada, Yuki; Seko, Noriaki; Nagasawa, Naotsugu; Tamada, Masao; Kasuya, Ken-ichi; Mitomo, Hiroshi

    2007-06-01

    Radiation-induced graft polymerization of vinyl acetate (VAc) onto poly(3-hydroxybutyrate) (PHB) film was carried out. At a degree of grafting higher than 5%, the grafted films (PHB-g-VAc) completely lost the enzymatic degradability that is characteristic of PHB due to the grafted VAc covering the surface of the PHB film. However, the biodegradability of the PHB-g-VAc films was recovered when the films were saponified in alkali solution under optimum conditions. Graft chains of the PHB-g-VAc film reacted selectively to become biodegradable polyvinyl alcohol (PVA). The biodegradability of the saponified PHB-g-VAc film increased rapidly with time.

  9. Biodegradability of poly(3-hydroxybutyrate) film grafted with vinyl acetate: Effect of grafting and saponification

    International Nuclear Information System (INIS)

    Wada, Yuki; Seko, Noriaki; Nagasawa, Naotsugu; Tamada, Masao; Kasuya, Ken-ichi; Mitomo, Hiroshi

    2007-01-01

    Radiation-induced graft polymerization of vinyl acetate (VAc) onto poly(3-hydroxybutyrate) (PHB) film was carried out. At a degree of grafting higher than 5%, the grafted films (PHB-g-VAc) completely lost the enzymatic degradability that is characteristic of PHB due to the grafted VAc covering the surface of the PHB film. However, the biodegradability of the PHB-g-VAc films was recovered when the films were saponified in alkali solution under optimum conditions. Graft chains of the PHB-g-VAc film reacted selectively to become biodegradable polyvinyl alcohol (PVA). The biodegradability of the saponified PHB-g-VAc film increased rapidly with time

  10. Cardiac and vascular malformations

    International Nuclear Information System (INIS)

    Ley, S.; Ley-Zaporozhan, J.

    2015-01-01

    Malformations of the heart and great vessels show a high degree of variation. There are numerous variants and defects with only few clinical manifestations and are only detected by chance, such as a persistent left superior vena cava or a partial anomalous pulmonary venous connection. Other cardiovascular malformations are manifested directly after birth and need prompt mostly surgical interventions. At this point in time echocardiography is the diagnostic modality of choice for morphological and functional characterization of malformations. Additional imaging using computed tomography (CT) or magnetic resonance imaging (MRI) is only required in a minority of cases. If so, the small anatomical structures, the physiological tachycardia and tachypnea are a challenge for imaging modalities and strategies. This review article presents the most frequent vascular, cardiac and complex cardiovascular malformations independent of the first line diagnostic imaging modality. (orig.) [de

  11. Computed tomography and magnetic resonance imaging in vascular surgical emergencies

    International Nuclear Information System (INIS)

    Vogelzang, R.L.; Fisher, M.R.

    1987-01-01

    Computed tomography (CT) scanning is now universally accepted as an extremely useful tool in the investigation of disease throughout the body. CT has revolutionized the practice of medicine in virtually every specialty. In vascular surgery the routine use of CT in a variety of problems has changed the way diagnoses are made. It allows prompt recognition of conditions that were difficult if not impossible to diagnose using older techniques. Nowhere is this concept better epitomized than in the realm of vascular surgical emergencies. In these cases, life or limb threatening conditions such as hemorrhage, prosthetic graft infection, or vascular occlusion exist as the result of aneurysm, trauma, dissection, tumor, or previous arterial surgery. Prompt and appropriate diagnosis of the immediate problem and its cause is afforded by the use of contrast enhanced CT. This frequently obviates the need for angiography and eliminates less accurate tests such as plain films, barium studies, nuclear medicine scans, and/or ultrasound. In the past several years magnetic resonance imaging (MRI) of the body has become a practical reality. The technique offers promise in the imaging of many disease processes. In the neural axis it has become a preferred modality due to inherently higher contrast resolution and freedom from artifacts. Progress in body imaging has been slower due to problems with motion artifact but early results in cardiovascular imaging demonstrate that MRI offers theoretical advantages over CT that may make it the imaging test of choice in vascular disease. This paper identifies those vascular surgical emergencies in which CT and MRI are most useful and clarifies and illustrates the diagnostic features of the various conditions encountered

  12. Cerebrovascular Accident Secondary to Paradoxical Embolism Following Arteriovenous Graft Thrombectomy

    Directory of Open Access Journals (Sweden)

    Jolina Pamela Santos

    2012-01-01

    Full Text Available Thrombectomy is a common procedure performed to declot thrombosed dialysis arteriovenous fistula (AVF or arteriovenous graft (AVG. Complications associated with access thrombectomy like pulmonary embolism have been reported, but paradoxical embolism is extremely rare. We report a case of a 74-year-old black man with past medical history significant for end-stage renal disease (ESRD, atrial fibrillation on anticoagulation with warfarin, who presented to our hospital with lethargy, aphasia, and right-sided hemiparesis following thrombectomy of a clotted AVG. Computed tomography (CT scan of brain showed a hypodensity within the left posterior parietal lobe. INR was 2.0 on admission. Echocardiogram revealed a normal sized left atrium with no intracardiac thrombus, and bubble study showed the presence of right-to-left shunting. These findings suggest that the stroke occurred as a result of an embolus originating from the AVG. Paradoxical cerebral embolism is uncommon but can occur after thrombectomy of clotted vascular access in ESRD patients. Clinicians and patients should be aware of this serious and potentially fatal complication of vascular access procedure.

  13. Cerebrovascular accident secondary to paradoxical embolism following arteriovenous graft thrombectomy.

    Science.gov (United States)

    Santos, Jolina Pamela; Hamadeh, Zaher; Ansari, Naheed

    2012-01-01

    Thrombectomy is a common procedure performed to declot thrombosed dialysis arteriovenous fistula (AVF) or arteriovenous graft (AVG). Complications associated with access thrombectomy like pulmonary embolism have been reported, but paradoxical embolism is extremely rare. We report a case of a 74-year-old black man with past medical history significant for end-stage renal disease (ESRD), atrial fibrillation on anticoagulation with warfarin, who presented to our hospital with lethargy, aphasia, and right-sided hemiparesis following thrombectomy of a clotted AVG. Computed tomography (CT) scan of brain showed a hypodensity within the left posterior parietal lobe. INR was 2.0 on admission. Echocardiogram revealed a normal sized left atrium with no intracardiac thrombus, and bubble study showed the presence of right-to-left shunting. These findings suggest that the stroke occurred as a result of an embolus originating from the AVG. Paradoxical cerebral embolism is uncommon but can occur after thrombectomy of clotted vascular access in ESRD patients. Clinicians and patients should be aware of this serious and potentially fatal complication of vascular access procedure.

  14. Effects of Human Adipose-Derived Stem Cells on the Survival of Rabbit Ear Composite Grafts

    Directory of Open Access Journals (Sweden)

    Chae Min Kim

    2017-09-01

    Full Text Available Background Composite grafts are frequently used for facial reconstruction. However, the unpredictability of the results and difficulties with large defects are disa