Endovascular management of renal transplant dysfunction secondary to hemodynamic effects related to ipsilateral femoral arteriovenous graft

Science.gov (United States)

Salsamendi, Jason; Pereira, Keith; Quintana, David; Bleicher, Drew; Tabbara, Marwan; Goldstein, Michael; Narayanan, Govindarajan

2016-01-01

Hemodialysis access options become complex in long-term treatment for patients with renal disease, while awaiting renal transplantation (RT). Once upper extremity sites are exhausted, lower extremities are used. RT is preferably in the contralateral iliac fossa, rarely ipsilateral. In current literature, RT dysfunction secondary to the hemodynamic effects of an ipsilateral femoral arteriovenous graft (AVG) has been rarely described. To our knowledge, AVG ligation is the only published technique for hemodynamic correction of an ipsilateral AVG. We present a simple, potentially reversible endovascular approach to manage the hemodynamic effects of an AVG, without potentially permanently losing future AVG access. PMID:26899147

MDCT angiography with 3D image reconstructions in the evaluation of failing arteriovenous fistulas and grafts in hemodialysis patients

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Dimopoulou, Angeliki; Raland, Hans; Magnusson, Anders (Dept. of Radiology, Univ. Hospital, Uppsala (Sweden)), email: angeliki.dimopoulou@akademiska.se; Wikstroem, Bjoern (Dept. of Medical Sciences, Renal Section, Univ. Hospital, Uppsala (Sweden))

2011-11-15

Background. Arteriovenous fistulas and grafts are the methods of choice for vascular access in renal failure patients in need of hemodialysis. Their major complication, however, is stenosis, which might lead to thrombosis. Purpose. To demonstrate the usefulness of 16-MDCTA with 3D image reconstructions, in long-term hemodialysis patients with dysfunctional arteriovenous fistulas and grafts (AVF and AVG). Material and Methods. During a 17-month period, 31 patients with dysfunctional AVF and AVG (24 AVF and seven AVG) were examined with MDCTA with 3D image postprocessing. Parameters such as comprehension of the anatomy, quality of contrast enhancement, and pathological vascular changes were measured. DSA was then performed in 24 patients. Results. MDCTA illustrated the anatomy of the AVF/AVG and the entire vascular tree to the heart, in a detailed and comprehensive manner in 93.5% of the evaluated segments, and depicted pathology of AVF/AVG or pathology of the associated vasculature. MDCTA demonstrated a total of 38 significant stenoses in 25 patients. DSA verified 37 stenoses in 24 patients and demonstrated two additional stenoses. MDCTA had thus a sensitivity of 95%. All 24 patients were treated with percutaneous transluminal angioplasty (PTA) with good technical results. Conclusion. MDCTA with 3D reconstructions of dysfunctioning AVFs and AVGs in hemodialysis patients is an accurate and reliable diagnostic method helping customize future intervention

MDCT angiography with 3D image reconstructions in the evaluation of failing arteriovenous fistulas and grafts in hemodialysis patients

International Nuclear Information System (INIS)

Dimopoulou, Angeliki; Raland, Hans; Magnusson, Anders; Wikstroem, Bjoern

2011-01-01

Background. Arteriovenous fistulas and grafts are the methods of choice for vascular access in renal failure patients in need of hemodialysis. Their major complication, however, is stenosis, which might lead to thrombosis. Purpose. To demonstrate the usefulness of 16-MDCTA with 3D image reconstructions, in long-term hemodialysis patients with dysfunctional arteriovenous fistulas and grafts (AVF and AVG). Material and Methods. During a 17-month period, 31 patients with dysfunctional AVF and AVG (24 AVF and seven AVG) were examined with MDCTA with 3D image postprocessing. Parameters such as comprehension of the anatomy, quality of contrast enhancement, and pathological vascular changes were measured. DSA was then performed in 24 patients. Results. MDCTA illustrated the anatomy of the AVF/AVG and the entire vascular tree to the heart, in a detailed and comprehensive manner in 93.5% of the evaluated segments, and depicted pathology of AVF/AVG or pathology of the associated vasculature. MDCTA demonstrated a total of 38 significant stenoses in 25 patients. DSA verified 37 stenoses in 24 patients and demonstrated two additional stenoses. MDCTA had thus a sensitivity of 95%. All 24 patients were treated with percutaneous transluminal angioplasty (PTA) with good technical results. Conclusion. MDCTA with 3D reconstructions of dysfunctioning AVFs and AVGs in hemodialysis patients is an accurate and reliable diagnostic method helping customize future intervention

Comprehensive Comparison of the Performance of Autogenous Brachial-Basilic Transposition Arteriovenous Fistula and Prosthetic Forearm Loop Arteriovenous Graft in a Multiethnic Asian Hemodialysis Population

Directory of Open Access Journals (Sweden)

Koy Min Chue

2016-01-01

Full Text Available Aim. For patients who have exhausted cephalic vein arteriovenous fistula (AVF options, controversy exists on whether brachial-basilic AVF with transposition (BBTAVF or a forearm arteriovenous graft (AVG should be the next vascular access of choice. This study compared the outcomes of these two modalities. Methods. A retrospective study of 122 Asian multiethnic patients who underwent either a BBTAVF (81 or an AVG (41. Maturation time and intervention rates were analyzed. Functional primary, secondary, and overall patency rates were evaluated. Results. The maturation time for BBTAVFs was significantly longer than AVGs. There was also a longer deliberation time before surgeons abandon a failing BBTAVF compared to an AVG. Both functional primary and secondary patency rates were significantly higher in the BBTAVF group at 1-year follow-up: 73.2% versus 34.1% (p<0.001 and 71.8% versus 54.3% (p=0.022, respectively. AVGs also required more interventions to maintain patency. When maturation rates were considered, the overall patency of AVGs was initially superior in the first 25 weeks after creation and then became inferior afterwards. Conclusion. BBTAVFs had superior primary and functional patency and required less salvage interventions. The forearm AVG might have a role in patients who require early vascular access due to complications from central venous catheters or with limited life expectancy.

Omega-3 Polyunsaturated Fatty Acid Supplementation to Prevent Arteriovenous Fistula and Graft Failure: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Science.gov (United States)

Viecelli, Andrea K; Irish, Ashley B; Polkinghorne, Kevan R; Hawley, Carmel M; Johnson, David W; Mori, Trevor A; Pascoe, Elaine M; Strippoli, Giovanni F M; Lok, Charmaine E; Palmer, Suetonia C

2018-01-27

Arteriovenous access failure frequently occurs in people on hemodialysis and is associated with morbidity, mortality and large healthcare expenditures. Omega-3 polyunsaturated fatty acids (omega-3 PUFA) may improve access outcomes via pleiotropic effects on access maturation and function, but may cause bleeding complications. Systematic review with meta-analysis. Adults requiring hemodialysis via arteriovenous fistula or graft. Trials evaluating omega-3 PUFA for arteriovenous access outcomes identified by searches in CENTRAL, MEDLINE, and Embase to 24 January 2017. Omega-3 PUFA. Primary patency loss, dialysis suitability failure, access abandonment, interventions to maintain patency or assist maturation, bleeding, gastrointestinal side-effects, all-cause and cardiovascular mortality, hospitalization, and treatment adherence. Treatment effects were summarized as relative risks (RR) and 95% confidence intervals (CI). Evidence was assessed using GRADE. Five eligible trials (833 participants) with a median follow-up of 12 months compared peri-operative omega-3 PUFA supplementation with placebo. One trial (n=567) evaluated treatment for fistulae and four (n=266) for grafts. Omega-3 PUFA supplementation prevented primary patency loss with moderate certainty (761 participants, RR 0.81, CI 0.68-0.98). Low quality evidence suggested, that omega-3 PUFA may have had little or no effect on dialysis suitability failure (536 participants, RR 0.95, CI 0.73-1.23), access abandonment (732 participants, RR 0.78, CI 0.59-1.03), need for interventions (732 participants, RR 0.82, CI 0.64-1.04), or all-cause mortality (799 participants, RR 0.99, CI 0.51-1.92). Bleeding risk (793 participants, RR 1.40, CI 0.78-2.49) or gastrointestinal side-effects (816 participants, RR 1.22, CI 0.64-2.34) from treatment were uncertain. There was no evidence of different treatment effects for grafts and fistulae. Small number and methodological limitations of included trials. Omega-3 PUFA supplementation

Interventional recanalization of artificial arteriovenous fistula and graft for hemodialysis: angioplasty and pulsed-spray thrombolysis with Urokinase

International Nuclear Information System (INIS)

Shin, Sung Wook; Do, Young Soo; Park, Hong Seok and others

1998-01-01

To evaluate the effectiveness of percutaneous transluminal angioplasty (PTA) and pul-sed-spray pharmaco-mechanical thrombolysis (PSPMT) using urokinase for the management of insufficient hemodialysis access. Between September 1996 and May 1998, 21 insufficient hemodialysis accesses were treated in 16 patients(3 artificial arteriovenous fistulae, AVF; and 13 arteriovenous graft, AVG). PTA and PSPMT were performed in 6 and 15 cases, respectively, and success and long-term patency rates were evaluated. The overall success rate of PTA and PSPMT for insufficient hemodialysis access was 76. 2%(16/21). The success rates of PTA and PSPMT were 83.3%(5/6) and 73.3%(11/15), respectively. The primary patency rates of PSPMT were 69±12.8% at 6 months and 38±18.6% at 12 months. One of the two initially successful PTAs had been patent for 7 months, and the second PTA was performed at that time due to venous stenosis. The other was patent for 15 months throughout the follow-up period. PTA and PSPMT are effective primary methods for the treatment of insufficient hemodialysis access;success and patency rates were high, and the procedures can be performed repeatedly.=20

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.

Expanded polytetrafluoroethylene graft fistula for chronic hemodialysis.

Science.gov (United States)

Tellis, V A; Kohlberg, W I; Bhat, D J; Driscoll, B; Veith, F J

1979-01-01

In a retrospective study of 66 PTFE arteriovenous fistulae and 71 BCH arteriovenous fistulae for dialysis access, PTFE had a higher patency rate than BCH at 12 months (62.4 versus 32.5%). PTFE was easier to work with and easier to handle in the face of infection. The lateral upper arm approach to placement of the PTFE graft is desirable in patients who have had multiple previous access procedures because this area is usually free from scarring, is distant from neurovascular structures, and provides a greater length of graft for needle punctures.

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.

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.

Is a Swine Model of Arteriovenous Malformation Suitable for Human Extracranial Arteriovenous Malformation? A Preliminary Study

Energy Technology Data Exchange (ETDEWEB)

Lv, Ming-ming, E-mail: lvmingming001@163.com [Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Department of Oral and Maxillofacial Surgery, Shanghai Key Laboratory of Stomatology (China); Fan, Xin-dong, E-mail: fanxindong@yahoo.com.cn [Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Department of Radiology (China); Su, Li-xin, E-mail: sulixin1975@126.com [Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Department of Oral and Maxillofacial Surgery, Shanghai Key Laboratory of Stomatology (China)

2013-10-15

Objective: A chronic arteriovenous malformation (AVM) model using the swine retia mirabilia (RMB) was developed and compared with the human extracranial AVM (EAVM) both in hemodynamics and pathology, to see if this brain AVM model can be used as an EAVM model. Methods: We created an arteriovenous fistula between the common carotid artery and the external jugular vein in eight animals by using end-to-end anastomosis. All animals were sacrificed 1 month after surgery, and the bilateral retia were obtained at autopsy and performed hematoxylin and eosin staining and immunohistochemistry. Pre- and postsurgical hemodynamic evaluations also were conducted. Then, the blood flow and histological changes of the animal model were compared with human EAVM. Results: The angiography after operation showed that the blood flow, like human EAVM, flowed from the feeding artery, via the nidus, drained to the draining vein. Microscopic examination showed dilated lumina and disrupted internal elastic lamina in both RMB of model and nidus of human EAVM, but the thickness of vessel wall had significant difference. Immunohistochemical reactivity for smooth muscle actin, angiopoietin 1, and angiopoietin 2 were similar in chronic model nidus microvessels and human EAVM, whereas vascular endothelial growth factor was significant difference between human EAVM and RMB of model. Conclusions: The AVM model described here is similar to human EAVM in hemodynamics and immunohistochemical features, but there are still some differences in anatomy and pathogenetic mechanism. Further study is needed to evaluate the applicability and efficacy of this model.

Is a Swine Model of Arteriovenous Malformation Suitable for Human Extracranial Arteriovenous Malformation? A Preliminary Study

International Nuclear Information System (INIS)

Lv, Ming-ming; Fan, Xin-dong; Su, Li-xin

2013-01-01

Objective: A chronic arteriovenous malformation (AVM) model using the swine retia mirabilia (RMB) was developed and compared with the human extracranial AVM (EAVM) both in hemodynamics and pathology, to see if this brain AVM model can be used as an EAVM model. Methods: We created an arteriovenous fistula between the common carotid artery and the external jugular vein in eight animals by using end-to-end anastomosis. All animals were sacrificed 1 month after surgery, and the bilateral retia were obtained at autopsy and performed hematoxylin and eosin staining and immunohistochemistry. Pre- and postsurgical hemodynamic evaluations also were conducted. Then, the blood flow and histological changes of the animal model were compared with human EAVM. Results: The angiography after operation showed that the blood flow, like human EAVM, flowed from the feeding artery, via the nidus, drained to the draining vein. Microscopic examination showed dilated lumina and disrupted internal elastic lamina in both RMB of model and nidus of human EAVM, but the thickness of vessel wall had significant difference. Immunohistochemical reactivity for smooth muscle actin, angiopoietin 1, and angiopoietin 2 were similar in chronic model nidus microvessels and human EAVM, whereas vascular endothelial growth factor was significant difference between human EAVM and RMB of model. Conclusions: The AVM model described here is similar to human EAVM in hemodynamics and immunohistochemical features, but there are still some differences in anatomy and pathogenetic mechanism. Further study is needed to evaluate the applicability and efficacy of this model

Suicide by severing the arterio-venous subclavian dialysis catheter.

Science.gov (United States)

Edirisinghe, P A S; Busuttil, A

2006-02-01

Haemodialysis access is an essential requirement for haemodialysis treatment in end-stage renal disease. The common forms are arteriovenous fistula (AVF) and arteriovenous grafts in ante-cubital fossa, forearm and upper thigh. Sometimes temporary or immediate access is created via a subclavian catheter or internal jugular catheter. This report is on a 79-year-old man who was suffering from chronic renal failure with a non-functional peripheral AVF; he was being dialysed through a permanent subclavian catheter and he became depressed due to continuing deterioration of his health. He used the easily accessible haemodialysis site as the method of suicide by cutting the tube that connected with the main vessel in his chest and bled to death. This highlights the requirement to assess carefully the patient's mental state in those on chronic haemodialysis, even though very few similar fatal cases have been previously reported.

Prefabrication of axial vascularized tissue engineering coral bone by an arteriovenous loop: A better model

International Nuclear Information System (INIS)

Dong Qingshan; Shang Hongtao; Wu Wei; Chen Fulin; Zhang Junrui; Guo Jiaping; Mao Tianqiu

2012-01-01

The most important problem for the survival of thick 3-dimensional tissues is the lack of vascularization in the context of bone tissue engineering. In this study, a modified arteriovenous loop (AVL) was developed to prefabricate an axial vascularized tissue engineering coral bone in rabbit, with comparison of the arteriovenous bundle (AVB) model. An arteriovenous fistula between rabbit femoral artery and vein was anastomosed to form an AVL. It was placed in a circular side groove of the coral block. The complex was wrapped with an expanded-polytetrafluoroethylene membrane and implanted beneath inguinal skin. After 2, 4, 6 and 8 weeks, the degree of vascularization was evaluated by India ink perfusion, histological examination, vascular casts, and scanning electron microscopy images of vascular endangium. Newly formed fibrous tissues and vasculature extended over the surfaces and invaded the interspaces of entire coral block. The new blood vessels robustly sprouted from the AVL. Those invaginated cavities in the vascular endangium from scanning electron microscopy indicated vessel's sprouted pores. Above indexes in AVL model are all superior to that in AVB model, indicating that the modified AVL model could more effectively develop vascularization in larger tissue engineering bone. - Highlights: ► A modified arteriovenous loop (AVL) model in rabbit was developed in this study. ► Axial prevascularization was induced in a larger coral block by using the AVL. ► The prefabrication of axial vascularized coral bone is superior as vascular carrier.

Proteomic Profiling in Early Venous Stenosis Formation in a Porcine Model of Hemodialysis Graft

Science.gov (United States)

Misra, Sanjay; Fu, Alex A.; Puggioni, Alessandra; Glockner, James F.; McKusick, Michael A.; Bjarnason, Haraldur; Mukhopadhyay, Debabrata

2009-01-01

PURPOSE To use proteomic analysis to identify up- and downregulated proteins in early venous stenosis formation in a porcine model of hemodialysis graft failure. MATERIALS AND METHODS Pigs had chronic renal insufficiency created by subtotal renal infarction caused by renal artery embolization. Arteriovenous polytetrafluoroethylene grafts were placed 28 days later and the animals were killed after a further 3 days (n = 4), 7 days (n = 4), or 14 days (n = 4). Proteomic analysis with isotope-coded affinity tags and multidimensional liquid chromatography followed by tandem mass spectrometry was performed on the venous stenosis and control vessels. Expression of proteins was further confirmed by Western blot analysis. The blood urea nitrogen (BUN) and creatinine levels were determined before renal artery embolization and at the time of graft placement. RESULTS At graft placement, mean BUN and creatinine levels were significantly higher than before embolization (P < .05). Six proteins were identified that were common to all four animals at the same time point. Five proteins (α-fetoprotein, fetuin A, macrophage migration inhibitory factor, pyruvate dehydrogenase E1 component, and lactoferrin) were upregulated and one protein (decorin) was downregulated. Expression of macrophage migration inhibitory factor, α-fetoprotein, and lactoferrin was further validated with Western blotting. By day 14, lactoferrin and fetuin-A expression were increased significantly in early venous stenosis formation. CONCLUSIONS Significantly increased expression of lactoferrin and fetuin-A were observed in early venous stenosis by day 14. Understanding the role of lactoferrin and fetuin-A in hemodialysis vascular access failure could help in improving outcomes in patients undergoing hemodialysis. PMID:19028119

Radiosurgery for brain arteriovenous malformations

International Nuclear Information System (INIS)

Latorzeff, I.; Schlienger, M.; Sabatier, J.; Borius, P.Y.; Lotterie, J.A.; Bourdin, S.; Menegalli, D.; Cognard, C.; Januel, A.C.; Desal, H.; Debono, B.; Blond, S.

2012-01-01

Radiosurgery as treatment for arteriovenous malformations has shown a good efficacy in reducing intracranial bleeding due to rupture. The choice of therapeutic modalities is based on evolutive risk and arteriovenous malformations volume, patient profile and risks stratification following therapeutic techniques (microsurgery, radiosurgery, embolization). Nidus size, arteriovenous malformations anatomical localization, prior embolization or bleeding, distributed dose are predictive factors for radio-surgery's good results and tolerance. This review article will highlight arteriovenous malformations radiosurgery indications and discuss recent irradiation alternatives for large arteriovenous malformation volumes. (authors)

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.

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.

Prefabrication of axial vascularized tissue engineering coral bone by an arteriovenous loop: a better model.

Science.gov (United States)

Dong, Qing-shan; Shang, Hong-tao; Wu, Wei; Chen, Fu-lin; Zhang, Jun-rui; Guo, Jia-ping; Mao, Tian-qiu

2012-08-01

The most important problem for the survival of thick 3-dimensional tissues is the lack of vascularization in the context of bone tissue engineering. In this study, a modified arteriovenous loop (AVL) was developed to prefabricate an axial vascularized tissue engineering coral bone in rabbit, with comparison of the arteriovenous bundle (AVB) model. An arteriovenous fistula between rabbit femoral artery and vein was anastomosed to form an AVL. It was placed in a circular side groove of the coral block. The complex was wrapped with an expanded-polytetrafluoroethylene membrane and implanted beneath inguinal skin. After 2, 4, 6 and 8 weeks, the degree of vascularization was evaluated by India ink perfusion, histological examination, vascular casts, and scanning electron microscopy images of vascular endangium. Newly formed fibrous tissues and vasculature extended over the surfaces and invaded the interspaces of entire coral block. The new blood vessels robustly sprouted from the AVL. Those invaginated cavities in the vascular endangium from scanning electron microscopy indicated vessel's sprouted pores. Above indexes in AVL model are all superior to that in AVB model, indicating that the modified AVL model could more effectively develop vascularization in larger tissue engineering bone. Copyright © 2012 Elsevier B.V. All rights reserved.

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.

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.

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....

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.

Comparison of Acute Thrombogenicity for Magnesium versus Stainless Steel Stents in a Porcine Arteriovenous Shunt Model.

Science.gov (United States)

Lipinski, Michael J; Acampado, Eduardo; Cheng, Qi; Adams, Lila; Torii, Sho; Gai, Jiaxiang; Torguson, Rebecca; Hellinga, David G; Joner, Michael; Harder, Claus; Zumstein, Philine; Finn, Aloke V; Kolodgie, Frank D; Virmani, Renu; Waksman, Ron

2018-05-08

Aims The aetiology for reduced thrombogenicity of the Magmaris resorbable magnesium scaffold (RMS) when compared with the Absorb bioresorbable vascular scaffold remains unclear. We therefore investigated whether the Magmaris RMS has platelet-repelling properties by comparing its acute thrombogenicity with an equivalent stainless steel stent in an arteriovenous shunt model. Methods and Results An ex vivo porcine carotid jugular arteriovenous shunt was established and connected to Sylgard tubing containing the Magmaris RMS with sirolimus-eluting PLLA coating and an equivalent 316L stainless steel stent with sirolimus-eluting PLLA coating. Six shunts (2 shunt runs per pig) were run comparing the 2 scaffolds (n=9) in alternating order. Nested generalised linear mixed models were employed to compare variables between scaffold groups. Confocal fluorescent microscopy costaining CD61/CD42b demonstrated that the 316L equivalent stent had significantly greater platelet coverage of the total scaffold compared with Magmaris (5.8% vs. 2.8%, Rate ratio 2.21 [1.41, 3.47], p=0.012). Scanning electron microscopy demonstrated significantly greater thrombus deposition on the 316L equivalent stent as a percentage of the total scaffold compared with Magmaris (8.0% vs. 5.3%, p=0.009). Magmaris also had significantly less CD14 positive monocyte deposition and a trend toward less PM-1 positive neutrophil compared with the 316L equivalent stent. Conclusion Despite having identical scaffold characteristics regarding geometrical design, Magmaris had significantly less thrombogenicity and inflammatory cell deposition compared with the equivalent 316L stainless steel stent in a porcine arteriovenous shunt model. These data suggest resorbable magnesium scaffolds may have inherent properties that reduce adhesion of platelets and inflammatory cells.

Arteriovenous Malformations

Science.gov (United States)

Arteriovenous malformations (AVMs) are defects in your vascular system. The vascular system includes arteries, veins, and capillaries. Arteries carry blood away from the heart to other organs; veins carry blood back to the heart. Capillaries connect the arteries and veins. An ...

Cardiac Arrest Secondary to Bilateral Pulmonary Emboli following Arteriovenous Fistula Thrombectomy: A Case Report with Review of the Literature

Directory of Open Access Journals (Sweden)

Avni Shah

2012-01-01

Full Text Available Number of patients with End Stage Renal Disease (ESRD is growing worldwide. Hemodialysis remains the main modality of renal replacement therapy for ESRD patients. A patent hemodialysis access (arteriovenous fistula or arteriovenous graft plays a key role in successful delivery of hemodialysis. Common vascular access issues encountered by patients and nephrologists are thrombosis and infection. The thrombosed access is declotted by various percutaneous techniques these days by multiple outpatient access centers in a timely fashion. Thrombolysis can give rise to various complications, a few of which can be life threatening. A young hemodialysis patient underwent percutaneous thrombolysis of his clotted arteriovenous fistula. Outpatient access thrombectomy was complicated immediately afterwards with cardiac arrest requiring cardiac resuscitation in the recovery room. The patient was admitted to intensive care unit after life sustaining care. Work up revealed multiple pulmonary emboli to both lung fields on CT scan of the chest. Patient was anticoagulated and discharged from the hospital. Thrombolysis of clotted hemodialysis access is associated commonly with occurrences of pulmonary embolic which are usually asymptomatic. Massive pulmonary embolization due to access thrombolysis is rare. Nephrologists and radiologists should be aware of this dangerous complication particularly in patients with preexisting cardiopulmonary disease.

Pulmonary arteriovenous fistulas

International Nuclear Information System (INIS)

Medeiros Sobrinho, J.H. de; Kambara, A.M.

1987-01-01

Six cases of pulmonary arteriovenous fistulas, isolated, without hemorrhagic hereditary telangiectasia (Rendu-Osler-Weber Symdrome) are reported emphasizing the radiographic, tomographic and angiographic examinations, (M.A.C.) [pt

Coronary Arteriovenous Fistula Causing Hydrops Fetalis

Directory of Open Access Journals (Sweden)

Nilüfer Çetiner

2014-01-01

Full Text Available Fetal heart failure and hydrops fetalis may occur due to systemic arteriovenous fistula because of increased cardiac output. Arteriovenous fistula of the central nervous system, liver, bone or vascular tumors such as sacrococcygeal teratoma were previously reported to be causes of intrauterine heart failure. However, coronary arteriovenous fistula was not reported as a cause of fetal heart failure previously. It is a rare pathology comprising 0.2–0.4% of all congenital heart diseases even during postnatal life. Some may remain asymptomatic for many years and diagnosed by auscultation of a continuous murmur during a routine examination, while a larger fistulous coronary artery opening to a low pressure cardiac chamber may cause ischemia of the affected myocardial region due to steal phenomenon and may present with cardiomyopathy or congestive heart failure during childhood. We herein report a neonate with coronary arteriovenous fistula between the left main coronary artery and the right ventricular apex, who presented with hydrops fetalis during the third trimester of pregnancy.

Evaluation of the degree of arteriovenous shunting in intracranial arteriovenous malformations using pseudo-continuous arterial spin labeling magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Sunwoo, Leonard; Park, Sun-Won [Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Department of Radiology, Seoul (Korea, Republic of); Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Sohn, Chul-Ho; Yun, Tae Jin; Choi, Seung Hong; Cho, Young Dae; Kim, Ji-hoon; Han, Moon Hee [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Lee, Jong Young [Kangdong Sacred Heart Hospital, Department of Neurosurgery, Seoul (Korea, Republic of); Yi, Kyung Sik [Chungbuk National University Hospital, Department of Radiology, Cheongju (Korea, Republic of); Paek, Sun Ha; Kim, Yong Hwy; Kim, Jin Wook; Chung, Hyun-Tai; Kim, Dong Gyu [Seoul National University Hospital, Department of Neurosurgery, Seoul (Korea, Republic of)

2015-08-15

Intracranial arteriovenous malformations (AVMs) display venous signals on arterial spin labeling (ASL) magnetic resonance (MR) imaging due to the presence of arteriovenous shunting. Our aim was to quantitatively correlate AVM signal intensity on ASL with the degree of arteriovenous shunting estimated on digital subtraction angiography (DSA) in AVMs. MR imaging including pseudo-continuous ASL at 3 T and DSA were obtained on the same day in 40 patients with intracranial AVMs. Two reviewers assessed the nidus and venous signal intensities on ASL images to determine the presence of arteriovenous shunting. Interobserver agreement on ASL between the reviewers was determined. ASL signal intensity of the AVM lesion was correlated with AVM size and the time difference between normal and AVM venous transit times measured from the DSA images. Interobserver agreement between two reviewers for nidus and venous signal intensities was excellent (κ = 0.80 and 1.0, respectively). Interobserver agreement regarding the presence of arteriovenous shunting was perfect (κ = 1.0). AVM signal intensity showed a positive relationship with the time difference between normal and AVM venous transit times (r = 0.638, P < 0.001). AVM signal intensity also demonstrated a positive relationship with AVM size (r = 0.561, P < 0.001). AVM signal intensity on ASL in patients with AVM correlates well with the degree of early vein opacification on DSA, which corresponds to the degree of arteriovenous shunting. (orig.)

Genetics Home Reference: capillary malformation-arteriovenous malformation syndrome

Science.gov (United States)

... Institute: How the Heart Works National Institute of Neurological Disorders and Stroke: Arteriovenous Malformation Educational Resources (7 links) Boston Children's Hospital: Arteriovenous Malformation Boston Children's Hospital: Capillary Malformation ...

Exercise-induced arteriovenous intrapulmonary shunting in dogs.

Science.gov (United States)

Stickland, Michael K; Lovering, Andrew T; Eldridge, Marlowe W

2007-08-01

We have previously shown, using contrast echocardiography, that intrapulmonary arteriovenous pathways are inducible in healthy humans during exercise; however, this technique does not allow for determination of arteriovenous vessel size or shunt magnitude. The purpose of this study was to determine whether large-diameter (more than 25 microm) intrapulmonary arteriovenous pathways are present in the dog, and whether exercise recruits these conduits. Through the right forelimb, 10.8 million 25-microm stable isotope-labeled microspheres (BioPAL, Inc., Worcester, MA) were injected either at rest (n = 8) or during high-intensity exercise (6- 8 mph, 10-15% grade, n = 6). Systemic arterial blood was continuously sampled during and for 3 minutes after injection. After euthanasia, tissue samples were obtained from the heart, liver, kidney, and skeletal muscle. In addition, 25- and 50-microm microspheres were infused into four isolated dog lungs that were ventilated and perfused at constant pressures similar to exercise. Blood and tissue samples were commercially analyzed for the presence of microspheres. No microspheres were detected in the arterial blood or tissue samples from resting dogs. In contrast, five of six exercising dogs showed evidence of exercise-induced intrapulmonary arteriovenous shunting, as microspheres were detected in arterial blood and/or tissue. Furthermore, shunt magnitude was calculated to be 1.4 +/- 0.8% of cardiac output (n = 3). Evidence of intrapulmonary arteriovenous anastomoses was also found in three of four isolated lungs. Consistent with previous human findings, these data demonstrate that intrapulmonary arteriovenous pathways are functional in the dog and are recruited with exercise.

Traumatic Intrarenal Arteriovenous Fistula Treated by Conservative ...

African Journals Online (AJOL)

1974-06-01

Jun 1, 1974 ... with these vascular lesions.' Varela' in 1928 reported the first case of intrarenal arteriovenous fistula. Arteriovenous fistula of the kidney is an ... and penetrating abdominal trauma, this lesion will be encountered with increasing frequency. Selective renal artery catheterisation aids materially in making the.

Arteriovenous malformation of the mandible

International Nuclear Information System (INIS)

Kim, Dong Youn; Lee, Kang Sook; Choi, Karp Shik

1995-01-01

The arteriovenous malformation, an uncommon lesion, is a direct communication between an artery and a vein that bypasses the intervening capillary bed. The authors experienced two cases of arteriovenous malformation in 17-year-old and 18-year-old female patients who had suffered from mandibular pain and gingival bleeding. As a result of careful analysis of clinical and angiographic radiological examinations, we diagnosed them as arteriovenous malformations. The following result were obtained; 1. Main clinical symptoms were dull pain and gingival bleeding on the mandibular body area and redness, pain on palpitation in the lesional sites were also observed. 2. Radiographically, well-defined radiolucent lesions with multiple osteolytic defects were observed. In radionuclide scan, increased uptakes of radioisotope were observed in the lesional sites. 3. Increased venous shunt supplied by the facial, lingual and inferior alveolar arteries was observed in angiography. After embolotherapy was performed, no recurrence was reported during 3 to 6 months follow up.

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

[Multiple coronary arteriovenous fistulae. Hazard or predetermination?].

Science.gov (United States)

Rangel, Alberto; Muñoz-Castellanos, Luis; Solorio, Sergio

2003-01-01

The authors present the clinical cases of three adult patients (49, 53 and 61 year-old), with rheumatic cardiac valvulopathy, and bilateral coronary arteriovenous fistulae draining in the main pulmonary artery. Based on documental investigation, the authors speculate about the predeterminate origin of coronary arteriovenous fistulae. At first glance, it seems obvious that congenital cardiopathies occur at random, i.e., embryonic development deviate or stops due to unknown reasons, originating the persistence of lacunar blood spaces prior to the development of coronary arteries cords. There are two factors involved in the genesis of congenital malformations: a genomic preexisting factor and the presence of an environmental precipitating factor, i.e., isolated pulmonary valve atresia or left ventricular hypoplastic syndrome, with mitral and aortic valve stenosis, can predispose development of coronary arteriovenous fistulae. Recently, the question has been raised whether there is a relation of coronary arteries fistulae with: ethnic groups, hereditary gigantism, autoimmune diseases, such as polymyositis, hereditary hemorrhagic telangiectasia, and apical hypertrophic myocardiopathy. Coronary arteriovenous fistulae, as well as some congenital cardiopathies, could be due to chromosome alterations or might be related to hereditary diseases, such as hemorrhagic telangiectasia, induced by a disturbed genetic program. Although, there is no concrete evidence that a genetic factor is related to the development of coronary arteriovenous fistulae, there are signs that suggest that such a possibility could be investigated.

Splenic arteriovenous fistula treated with percutaneous transarterial embolization

DEFF Research Database (Denmark)

Madsen, M.A.; Frevert, S.; Madsen, P.L.

2008-01-01

Splenic arteriovenous fistula is a rare complication following splenectomy. We report a case of a large splenic arteriovenous fistula 23 years after splenectomy in a 50-year old male with abdominal pain, gastro-intestinal bleeding, ascites, diarrhoea, dyspnoea, portal hypertension and heart failure...

Rabbit Calvarial Defect Model for Customized 3D-Printed Bone Grafts.

Science.gov (United States)

Lee, Kang-Gon; Lee, Kang-Sik; Kang, Yu-Jeoung; Hwang, Jong-Hyun; Lee, Se-Hwan; Park, Sang-Hyug; Park, Yongdoo; Cho, Young-Sam; Lee, Bu-Kyu

2018-05-01

Bone graft materials are commonly used to regenerate various bone defects, but their application is often limited because of the complex defect shape in various clinical conditions. Hence, customized bone grafts using three-dimensional (3D) printing techniques have been developed. However, conventional simple bone defect models are limited for evaluating the benefits and manufacturing accuracy of 3D-printed customized bone grafts. Thus, the aim of the present study was to develop a complex-shaped bone defect model. We designed an 8-shaped bony defect that consists of two simple circles attached to the rabbit calvarium. To determine the critical-sized defect (CSD) of the 8-shaped defects, 5.6- and 7-mm-diameter trephine burs were tested, and the 7-mm-diameter bur could successfully create a CSD, which was easily reproducible on the rabbit calvarium. The rate of new bone formation was 28.65% ± 8.63% at 16 weeks following creation of the defect. To confirm its efficacy for clinical use, the 8-shaped defect was created on a rabbit calvarium and 3D computed tomography (CT) was performed. A stereolithography file was produced using the CT data, and a 3D-printed polycaprolactone graft was fabricated. Using our 8-shaped defect model, we were able to modify the tolerances of the bone graft and calvarial defect to fabricate a more precise bone graft. Customized characteristics of the bone graft were then used to improve the accuracy of the bone graft. In addition, we confirmed the fitting ability of the 3D-printed graft during implantation of the graft. Our 8-shaped defect model on the rabbit calvarium using a 7.0-mm trephine bur may be a useful CSD model for evaluating 3D-printed graft materials.

Rendu-Osler-Weber syndrome presenting with pulmonary arteriovenous fistula

International Nuclear Information System (INIS)

Halefoglu, A.M.

2005-01-01

A pulmonary arteriovenous fistula is an abnormal connection between pulmonary arteries and veins. Patients with Rendu-Osler-Weber syndrome may present with this vascular malformation, which is a typical finding of the disease. Approximately 5-15% of Rendu-Osler-Weber syndrome patients have pulmonary arteriovenous malformations (AVM) and there is usually a family history of AVM in these patients. The malformations are usually located in the lower lobes. In this paper, I describe a 49-year-old male patient with dyspnoea, cough, haemoptysis and epistaxis. Physical examination showed nasal telangiectasias, cyanosis of the lips and nails, and a systolic bruit over the left lung. Chest X-ray revealed a 5-cm mass in the left lower lobe and after magnetic resonance examination, together with 3-D magnetic resonance angiography, it was demonstrated to be a pulmonary arteriovenous fistula. The history of a niece with a similar history of suspected pulmonary arteriovenous fistula led me to consider the possibility of Rendu-Osler-Weber syndrome presenting with a pulmonary arteriovenous fistula. Copyright (2005) Blackwell Science Pty Ltd

Maturation of arteriovenous fistula: Analysis of key factors

Directory of Open Access Journals (Sweden)

Muhammad A. Siddiqui

2017-12-01

Full Text Available The growing proportion of individuals suffering from chronic kidney disease has considerable repercussions for both kidney specialists and primary care. Progressive and permanent renal failure is most frequently treated with hemodialysis. The efficiency of hemodialysis treatment relies on the functional status of vascular access. Determining the type of vascular access has prime significance for maximizing successful maturation of a fistula and avoiding surgical revision. Despite the frequency of arteriovenous fistula procedures, there are no consistent criteria applied before creation of arteriovenous fistulae. Increased prevalence and use of arteriovenous fistulae would result if there were reliable criteria to assess which arteriovenous fistulae are more likely to reach maturity without additional procedures. Published studies assessing the predictive markers of fistula maturation vary to a great extent with regard to definitions, design, study size, patient sample, and clinical factors. As a result, surgeons and specialists must decide which possible risk factors are most likely to occur, as well as which parameters to employ when evaluating the success rate of fistula development in patients awaiting the creation of permanent access. The purpose of this literature review is to discuss the role of patient factors and blood markers in the development of arteriovenous fistulae.

Arteriovenous Malformation of the Pancreas

Directory of Open Access Journals (Sweden)

Alexandros Charalabopoulos

2011-01-01

Full Text Available Pancreatic arteriovenous malformation (PAVM is a very rare and mostly congenital lesion, with less than 80 cases described in the English-published literature. It is defined as a tumorous vascular abnormality that is constructed between an anomalous bypass anastomosis of the arterial and venous networks within the pancreas. It represents about 5% of all arteriovenous malformations found in the gastrointestinal tract. Herein, we present a 64-year-old patient with symptomatic PAVM involving the body and tail of the organ, which was successfully treated by transcatheter arterial embolization. The disease spectrum and review of the literature are also presented.

Striatal grafts in a rat model of Huntington's disease

DEFF Research Database (Denmark)

Guzman, R; Meyer, M; Lövblad, K O

1999-01-01

Survival and integration into the host brain of grafted tissue are crucial factors in neurotransplantation approaches. The present study explored the feasibility of using a clinical MR scanner to study striatal graft development in a rat model of Huntington's disease. Rat fetal lateral ganglionic...... time-points graft location could not be further verified. Measures for graft size and ventricle size obtained from MR images highly correlated with measures obtained from histologically processed sections (R = 0.8, P fetal rat lateral ganglionic...

Comparison of Acute Thrombogenicity for Metallic and Polymeric Bioabsorbable Scaffolds: Magmaris Versus Absorb in a Porcine Arteriovenous Shunt Model.

Science.gov (United States)

Waksman, Ron; Lipinski, Michael J; Acampado, Eduardo; Cheng, Qi; Adams, Lila; Torii, Sho; Gai, Jiaxiang; Torguson, Rebecca; Hellinga, David M; Westman, Peter C; Joner, Michael; Zumstein, Philine; Kolodgie, Frank D; Virmani, Renu

2017-08-01

A comparison in acute thrombogenicity between the Magmaris sirolimus-eluting bioabsorbable magnesium scaffold and the Absorb bioresorbable vascular scaffold has not been performed. This study assessed acute thrombogenicity of Magmaris compared with Absorb and the Orsiro hybrid drug-eluting stent in a porcine arteriovenous shunt model. An ex vivo porcine carotid jugular arteriovenous shunt was established and connected to SYLGARD tubing containing the Magmaris, Absorb, and Orsiro scaffolds/stents and allowed to run in the shunt for a maximum of 1 hour. Twelve shunts (2 shunt runs per pig) were run comparing the 3 scaffolds in alternating order. Nested generalized linear mixed models were used to compare variables between scaffold groups while adjusting for variability between shunt runs. Confocal fluorescent microscopy costaining CD61/CD42b demonstrated that both Magmaris (3.0%) and Orsiro (4.6%) had less platelet coverage of the total scaffold compared with Absorb (21.8%). Scanning electron microscopy demonstrated significantly less thrombus deposition to Magmaris as a percentage of the total scaffold compared with Absorb (5.0% versus 16.1%, P =0.02). Magmaris had significantly less PM-1-positive neutrophil and CD14-positive monocyte adherence compared with both Orsiro and Absorb. Orsiro had significantly less monocyte deposition compared with Absorb. Despite a similar scaffold strut thickness, the Magmaris sirolimus-eluting bioabsorbable magnesium scaffold was significantly less thrombogenic compared with the Absorb bioresorbable vascular scaffold in an ex vivo porcine arteriovenous shunt model. Further studies are needed to determine whether the reduced thrombogenicity of Magmaris will result in reductions in major cardiovascular events. © 2017 American Heart Association, Inc.

Appraising the plasticity of the circle of Willis: a model of hemodynamic modulation in cerebral arteriovenous malformations.

Science.gov (United States)

Chuang, Yu-Ming; Guo, Wanyuo; Lin, Ching-Po

2010-01-01

Cerebral arteriovenous malformations (AVMs) harbor a network of abnormal vasculatures, namely the nidus between arterial and venous components. The pressure gradient between these two components results in abnormal high-velocity arteriovenous shunts flowing through the nidus and alternate intracranial hemodynamics. This study hypothesizes that the flow patterns of the circle of Willis (CoW) are modulated by the alternation of intracranial hemodynamics occurring in cerebral AVMs. The flow patterns of the CoW before and after AVMs had been corrected and the arteriovenous shunts closed by radiosurgery were assessed to validate the hypothesis. Fifty patients (32 men and 18 women; mean age 35.8 +/- 4.2, range 23-52 years) with cerebral AVMs previously treated by radiosurgery were retrospectively investigated. This investigation used magnetic resonance angiography, performed prior to and after AVM surgery, to assess the CoW flow patterns. The CoW flow patterns in nearly half of the subjects (20/50, 40%) altered after the AVMs had been corrected. The alterations included: (1) decreased size or ceased flow patterns in the CoW vascular segment: ipsilateral A1 (n = 1) of the anterior cerebral artery (ACA), ipsilateral posterior communicating artery (PCoA) segment (n = 7), contralateral PCoA collateral (n = 4), bilateral PCoA (n = 2); (2) increased size or opening of the previous 'hypoplastic' segment of CoW: ipsilateral A1 of ACA (n = 1), contralateral PCoA (n = 2), bilateral PCoA (n = 1), and (3) biphasic alteration of the CoW: ceased ipsilateral PCoA segment and opening ipsilateral A1 of the ACA (n = 1), ceased ipsilateral PCoA and opening contralateral P1 of the posterior cerebral artery (n = 1). The plasticity of the flow patterns in the CoW are modulated by intracranial hemodynamics as shown by the AVM model. The calibers of CoW arterial segments are not a static feature. Willisian collateralization with recruitment of the CoW segment may cease, or hypoplastic segments

Surgical Treatment for a Complex Congenital Arteriovenous Malformation of the Lower Limb

OpenAIRE

Ozcan, Ali Vefa; Boysan, Emre; Isikli, Osman Yasar; Goksin, Ibrahim

2013-01-01

Arteriovenous fistula is defined as an abnormal communication between the arterial and venous systems. The complexity of congenital arteriovenous malformations makes treatment challenging. We present the case of a 23-year-old woman who had a complex congenital arteriovenous malformation in her left leg and a history of 2 unsuccessful coil-embolization procedures. We ligated all the feeding arteries of the arteriovenous malformation in the region of the superficial femoral artery, and the surg...

Renal arteriovenous shunts, fistulae and malformations - angiographic case reports

International Nuclear Information System (INIS)

Esser, P.W.; Duex, A.

1989-01-01

Individual case reports serve to demonstrate the pathogenetically different renal arteriovenous shunt formations, such as congenital arteriovenous angioma, spontaneous arteriovenous aneurysm, iatrogenic arterio-venous fistula and neoplasia-conditioned arteriovenous fistula. These are discussed in detail, including treatment possibilities. The ranking of digital subtraction angiography is emphasised. Our case reports show that in preoperative diagnosis of pathological structures in the kidney, renovasography is an invaluable tool, especially with i.a. DSA technique, and is superior to all other methods such as sonography, CT, MR and colour-coded Doppler sonography. Due to improved techniques of angiography (markedly lower amounts of contrast medium when using catheters of narrow lumen) indication for i.a. DSA in haematuria of unknown origin should be liberal. Above all, the method should be performed at an early stage. If there is a NAD renal finding in the i.a. DSA renovasogram in renally conditioned haematuria even when using a 1024 x 1024 image matrix, it is advisable to perform selective renal arteriography to either exclude or confirm the existence of an intrarenal angioma, additionally in conventional sheet film technique because of the superior power of resolution. (orig.) [de

Rule-based model of vein graft remodeling.

Directory of Open Access Journals (Sweden)

Minki Hwang

Full Text Available When vein segments are implanted into the arterial system for use in arterial bypass grafting, adaptation to the higher pressure and flow of the arterial system is accomplished thorough wall thickening and expansion. These early remodeling events have been found to be closely coupled to the local hemodynamic forces, such as shear stress and wall tension, and are believed to be the foundation for later vein graft failure. To further our mechanistic understanding of the cellular and extracellular interactions that lead to global changes in tissue architecture, a rule-based modeling method is developed through the application of basic rules of behaviors for these molecular and cellular activities. In the current method, smooth muscle cell (SMC, extracellular matrix (ECM, and monocytes are selected as the three components that occupy the elements of a grid system that comprise the developing vein graft intima. The probabilities of the cellular behaviors are developed based on data extracted from in vivo experiments. At each time step, the various probabilities are computed and applied to the SMC and ECM elements to determine their next physical state and behavior. One- and two-dimensional models are developed to test and validate the computational approach. The importance of monocyte infiltration, and the associated effect in augmenting extracellular matrix deposition, was evaluated and found to be an important component in model development. Final model validation is performed using an independent set of experiments, where model predictions of intimal growth are evaluated against experimental data obtained from the complex geometry and shear stress patterns offered by a mid-graft focal stenosis, where simulation results show good agreements with the experimental data.

Pulmonale arteriovenøse malformationer, moderne behandlingsprincipper

DEFF Research Database (Denmark)

Andersen, P E; Kjeldsen, A D

2001-01-01

Pulmonary arteriovenous malformations are congenital vascular malformations in the lungs, which act as shunts so that the blood is not oxygenated or filtered. These patients are typically hypoxaemic with exercise intolerance and are at high risk of paradoxical emboli to the brain. About 25...... technical success and few complications. Embolisation prevents cerebral stroke and abscess and pulmonary haemorrhage and further raises the functional level. Screening for pulmonary arteriovenous malformations in patients at risk is recommended....

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.

Anaesthetic management of a child with massive extracranial arteriovenous malformation

Directory of Open Access Journals (Sweden)

Faisal Shamim

2012-01-01

Full Text Available Vascular tumors affect the head and neck commonly but arteriovenous malformations are rare. Vascular malformations are often present at birth and grow with the patient, usually only becoming significant later in childhood. Embolization has been the mainstay of treatment in massive and complex arteriovenous malformations. We present a case of massive extracranial arteriovenous malformation in a 7-year-old boy causing significant workload on right heart and respiratory distress. The management of angioembolization under general anaesthesia and anaesthetic concerns are presented.

Controlled grafting of vinylic monomers on polyolefins: a robust mathematical modeling approach.

Science.gov (United States)

Saeb, Mohammad Reza; Rezaee, Babak; Shadman, Alireza; Formela, Krzysztof; Ahmadi, Zahed; Hemmati, Farkhondeh; Kermaniyan, Tayebeh Sadat; Mohammadi, Yousef

2017-01-01

Experimental and mathematical modeling analyses were used for controlling melt free-radical grafting of vinylic monomers on polyolefins and, thereby, reducing the disturbance of undesired cross-linking of polyolefins. Response surface, desirability function, and artificial intelligence methodologies were blended to modeling/optimization of grafting reaction in terms of vinylic monomer content, peroxide initiator concentration, and melt-processing time. An in-house code was developed based on artificial neural network that learns and mimics processing torque and grafting of glycidyl methacrylate (GMA) typical vinylic monomer on high-density polyethylene (HDPE). Application of response surface and desirability function enabled concurrent optimization of processing torque and GMA grafting on HDPE, through which we quantified for the first time competition between parallel reactions taking place during melt processing: (i) desirable grafting of GMA on HDPE; (ii) undesirable cross-linking of HDPE. The proposed robust mathematical modeling approach can precisely learn the behavior of grafting reaction of vinylic monomers on polyolefins and be placed into practice in finding exact operating condition needed for efficient grafting of reactive monomers on polyolefins.

Physical examination of the hemodialysis arteriovenous fistula to detect early dysfunction.

Science.gov (United States)

Abreo, Kenneth; Amin, Bakhtiar M; Abreo, Adrian P

2018-04-01

The maintenance of vascular access patency for end-stage renal disease patients on hemodialysis is necessary for survival. Many nephrologists, nurse practitioners, and nurses have limited experience with the physical examination of the arteriovenous fistula. In this review, we define key terms used in the assessment of an arteriovenous fistula. We discuss the arteriovenous fistula physical exam, including details of inspection, palpation, and auscultation. Using these concepts, we review the abnormal findings that can assist practitioners in determining the location of a stenosis. We review the existing literature that validates physical exam findings with gold standard tests such as ultrasound and angiography. Finally, we review data supporting the value of training physicians and nurses in arteriovenous fistula physical examination.

Transarterial embolization for hematuria caused by renal arteriovenous malformations or fistulae

International Nuclear Information System (INIS)

Meng Xiaoxi; Liu Shiyuan; Dong Weihua; Dong Sheng; Jia Ningyang; Xiao Xiangsheng

2008-01-01

Objective: To evaluate the efficacy and safety of transarterial embolization for hematuria caused by renal arteriovenous malformation or fistulae. Methods: Seven patients with gross hematuria caused by renal arterial abnormalities were retrospectively reviewed, of which three had congenital renal arteriovenous malformations and the other four had non-neoplastic acquired renal arteriovenous fistulae. All patients were confirmed by renal arterial angiography and undergone embolization with various embolic materials. Results: Embolization was successfully carried out in all cases. Gross hematuria disappeared one to seven days after the procedure. No severe complications were encountered. No recurrence occurred within 12 to 36 months of follow-up. Conclusions: Transarterial embolization is safe and effective for hematuria caused by renal arteriovenous malformations or fistulae. (authors)

Surgical excision of a cerebral arteriovenous malformation in a dog

International Nuclear Information System (INIS)

Thomas, W.B.; Schueler, R.O.; Kornegay, J.N.

1995-01-01

A 7-year-old dog was presented with seizures and epistaxis. Computed tomography showed a contrast-enhancing lesion in the cerebrum. An arteriovenous malformation was identified at surgery and resected. A discussion of intracranial arteriovenous malformation is presented

Choice of Hemodialysis Access in Older Adults: A Cost-Effectiveness Analysis.

Science.gov (United States)

Hall, Rasheeda K; Myers, Evan R; Rosas, Sylvia E; O'Hare, Ann M; Colón-Emeric, Cathleen S

2017-06-07

Although arteriovenous fistulas have been found to be the most cost-effective form of hemodialysis access, the relative benefits of placing an arteriovenous fistula versus an arteriovenous graft seem to be least certain for older adults and when placed preemptively. However, older adults' life expectancy is heterogeneous, and most patients do not undergo permanent access creation until after dialysis initiation. We evaluated cost-effectiveness of arteriovenous fistula placement after dialysis initiation in older adults as a function of age and life expectancy. Using a hypothetical cohort of patients on incident hemodialysis with central venous catheters, we constructed Markov models of three treatment options: ( 1 ) arteriovenous fistula placement, ( 2 ) arteriovenous graft placement, or ( 3 ) continued catheter use. Costs, utilities, and transitional probabilities were derived from existing literature. Probabilistic sensitivity analyses were performed by age group (65-69, 70-74, 75-79, 80-84, and 85-89 years old) and quartile of life expectancy. Costs, quality-adjusted life-months, and incremental cost-effectiveness ratios were evaluated for up to 5 years. The arteriovenous fistula option was cost effective compared with continued catheter use for all age and life expectancy groups, except for 85-89 year olds in the lowest life expectancy quartile. The arteriovenous fistula option was more cost effective than the arteriovenous graft option for all quartiles of life expectancy among the 65- to 69-year-old age group. For older age groups, differences in cost-effectiveness between the strategies were attenuated, and the arteriovenous fistula option tended to only be cost effective in patients with life expectancy >2 years. For groups for which the arteriovenous fistula option was not cost saving, the cost to gain one quality-adjusted life-month ranged from $2294 to $14,042. Among older adults, the cost-effectiveness of an arteriovenous fistula placed within the first

Surgical treatment for a complex congenital arteriovenous malformation of the lower limb.

Science.gov (United States)

Ozcan, Ali Vefa; Boysan, Emre; Isikli, Osman Yasar; Goksin, Ibrahim

2013-01-01

Arteriovenous fistula is defined as an abnormal communication between the arterial and venous systems. The complexity of congenital arteriovenous malformations makes treatment challenging. We present the case of a 23-year-old woman who had a complex congenital arteriovenous malformation in her left leg and a history of 2 unsuccessful coil-embolization procedures. We ligated all the feeding arteries of the arteriovenous malformation in the region of the superficial femoral artery, and the surgery was successful without sequelae. The patient returned 2 years later with thrombosis of the great saphenous vein and underwent a second operation. The thrombosed vein and all varicosities were excised successfully. Surgery can be an effective method for correcting complex congenital arteriovenous malformations, especially in the lower limbs. A 2-staged surgical approach like ours might be a good option in suitable patients.

Screening for pulmonary arteriovenous malformations

DEFF Research Database (Denmark)

Oxhøj, H; Kjeldsen, A D; Nielsen, G

2000-01-01

Pulmonary arteriovenous malformations (PAVM) cause right-to-left shunt and imply risk of paradoxical embolism and cerebral abscess. These complications can be prevented by appropriate treatment. Detection of PAVMs is therefore important, so simple and reliable screening methods are needed...... for this purpose. The aim of this investigation was to compare pulse oximetry and contrast echocardiography as screening tools for detection of pulmonary arteriovenous malformations. Eighty-five hereditary haemorrhagic telangiectasia (HHT) patients and first-degree relatives identified in a comprehensive study...... echocardiography with intravenous injection of echo contrast was performed in all subjects. Outcome measures were oxygen saturation change >2% units on changing body position and echo contrast observed in the left-sided heart chambers. Positive contrast echocardiography indicating the presence of PAVM was found...

Transcatheter arterial ethanol embolization for congenital renal arteriovenous malformations

International Nuclear Information System (INIS)

Wang Jingbing; Wang Han; An Xiao; Wang Linchuan; Gao Liqiang; Zhou Zhiguo; Zhang Guixiang

2010-01-01

Objective: To discuss the effect and safety of trans-microcatheter arterial embolization with ethanol for the treatment of congenital renal arteriovenous malformations. Methods: Clinical data of 11 patients with congenital renal arteriovenous malformations manifested mainly as gross hematuria were retrospectively analyzed. Selective renal angiography was performed in all 11 patients. After the diagnosis was confirmed, super-selective catheterization of the diseased arteries was carried out and the trans-microcatheter arterial embolization with ethanol was conducted. Results: A total of 12 procedures were completed in 11 patients. The ethanol dose used in one procedure was 5-25 ml. Successful embolization of the congenital renal arteriovenous malformations was obtained in all patients. The gross hematuria disappeared within 24-48 hours after the treatment. Lumbago at treated side, low fever, abdominal distension, nausea, vomiting, etc. occurred within one week and no other serious complications developed. During the follow-up period lasting for 4-96 months, no recurrence of hematuria was observed and the renal function remained normal. Conclusion: Transcatheter arterial ethanol embolization is an economic, safe and effective treatment for congenital renal arteriovenous malformations. (authors)

Transcatheter arterial embolization for congenital renal arteriovenous malformation

International Nuclear Information System (INIS)

Zhou Jun; Hu Tingyang; Yuan Jianhua; Yu Wenqiang

2008-01-01

Objective: To evaluate the effectiveness of transcatheter arterial embolization for congenital renal arteriovenous malformation. Methods: Seven cases of congenital renal arteriovenous malformation causing gross hematuria were retrospectively studied. All of 7 cases were demonstrated by means of angiography and then the catheter was placed superselectively into the involved arterial end of the malformation undertaking embolization with gelfoam, dehydrated ethanol, coils, etc. Results: All the malformations of the 7 cases were successfully embolized with stoppage of gross hematuria within 24 hours. No serious complications occurred except lumbago, fever, gastrointestinal reaction for one week. There was no recurrence of haematuria and the renal function was also normal in all cases during the follow-up for 36 to 98 months. Conclusions: Transcatheter renal arterial angiography and embolization are the important and effective management for the diagnosis and treatment of congenital renal arteriovenous malformation. (authors)

Dynamics in coarse-grained models for oligomer-grafted silica nanoparticles

KAUST Repository

Hong, Bingbing

2012-01-01

Coarse-grained models of poly(ethylene oxide) oligomer-grafted nanoparticles are established by matching their structural distribution functions to atomistic simulation data. Coarse-grained force fields for bulk oligomer chains show excellent transferability with respect to chain lengths and temperature, but structure and dynamics of grafted nanoparticle systems exhibit a strong dependence on the core-core interactions. This leads to poor transferability of the core potential to conditions different from the state point at which the potential was optimized. Remarkably, coarse graining of grafted nanoparticles can either accelerate or slowdown the core motions, depending on the length of the grafted chains. This stands in sharp contrast to linear polymer systems, for which coarse graining always accelerates the dynamics. Diffusivity data suggest that the grafting topology is one cause of slower motions of the cores for short-chain oligomer-grafted nanoparticles; an estimation based on transition-state theory shows the coarse-grained core-core potential also has a slowing-down effect on the nanoparticle organic hybrid materials motions; both effects diminish as grafted chains become longer. © 2012 American Institute of Physics.

Irradiation inhibits vascular anastomotic stenosis in a canine model

International Nuclear Information System (INIS)

Saito, Takeshi; Iguchi, Atsushi; Tabayashi, Koichi

2009-01-01

The graft patency rate after coronary artery bypass grafting (CABG) correlates with anastomotic stenosis. Intracoronary radiation therapy is effective for preventing restenosis after percutaneous coronary intervention (PCI). We postulated that intracoronary radiation therapy could prevent anastomotic stenosis and tested this hypothesis in an animal model. Femoral arteries and veins of beagle dogs were harvested, and composite arterioarterial and arteriovenous grafts were prepared. After external irradiation of the anastomotic sites, these composite grafts were transplanted into femoral arteries. Histomorphometric and immunohistological analyses of the anastomotic sites were performed. The study groups consisted of controls and animals exposed to 10 Gy, 20 Gy, and 30 Gy (n=5, in each group). In the artery graft model, the ratio of negative remodeling was significantly increased in all groups exposed to ≥10 Gy. The ratio of neointimal hyperplasia was significantly decreased in all groups exposed to ≥10 Gy. Cell density of anti-α-actin antibody-positive cells and anti-proliferating cell nuclear antigen (PCNA) antibody-positive cells was highest in the adventitial layer, and the density decreased as the dosage increased. Experimental results were almost the same in the vein graft models as in the artery graft models. With double immunohistostaining, the anti-PCNA antibody-positive cells expressed α-actin. Irradiation can inhibit anastomotic stenosis in a canine model. Adventitia is a factor in the creation of stenosis, and irradiation appears to target the adventitia. We speculate that there might be a possible role for intracoronary irradiation in the future to prevent anastomotic stenosis. (author)

Complications from arteriovenous malformation radiosurgery: multivariate analysis and risk modeling

International Nuclear Information System (INIS)

Flickinger, John C.; Kondziolka, Douglas; Pollock, Bruce E.; Maitz, Ann H.; Lunsford, L. Dade

1997-01-01

Purpose/Objective: To assess the relationships of radiosurgery treatment parameters to the development of complications from radiosurgery for arteriovenous malformations (AVM). Methods and Materials: We evaluated follow-up imaging and clinical data in 307 AVM patients who received gamma knife radiosurgery at the University of Pittsburgh between 1987 and 1993. All patients had regular clinical or imaging follow up for a minimum of 2 years (range: 24-96 months, median = 44 months). Results: Post-radiosurgical imaging (PRI) changes developed in 30.5% of patients with regular follow-up magnetic resonance imaging, and were symptomatic in 10.7% of all patients at 7 years. PRI changes resolved within 3 years developed significantly less often (p = 0.0274) in patients with symptoms (52.8%) compared to asymptomatic patients (94.8%). The 7-year actuarial rate for developing persistent symptomatic PRI changes was 5.05%. Multivariate logistic regression modeling found that the 12 Gy volume was the only independent variable that correlated significantly with PRI changes (p < 0.0001) while symptomatic PRI changes were correlated with both 12 Gy volume (p = 0.0013) and AVM location (p 0.0066). Conclusion: Complications from AVM radiosurgery can be predicted with a statistical model relating the risks of developing symptomatic post-radiosurgical imaging changes to 12 Gy treatment volume and location

Determination of blood flow through arteriovenous fistulae and shunts

International Nuclear Information System (INIS)

Lantz, B.M.T.; Holcroft, J.W.; Foerster, J.M.; Link, D.P.; Reid, M.H.

1979-01-01

A videodensitometric method for estimating relative flow was employed in a patient with a bovine arteriovenous fistula. Analogous arteriovenous communications of different sizes were created in two dogs for comparison. Local and general hemodynamic parameters were measured. The videodensitometric method proved to be highly accurate compared to electromagnetic flow readings and is the method of choice in estimating shunt flow in connection with routine angiography. (Auth.)

A Rabbit Model for Testing Helper-Dependent Adenovirus-Mediated Gene Therapy for Vein Graft Atherosclerosis.

Science.gov (United States)

Bi, Lianxiang; Wacker, Bradley K; Bueren, Emma; Ham, Ervin; Dronadula, Nagadhara; Dichek, David A

2017-12-15

Coronary artery bypass vein grafts are a mainstay of therapy for human atherosclerosis. Unfortunately, the long-term patency of vein grafts is limited by accelerated atherosclerosis. Gene therapy, directed at the vein graft wall, is a promising approach for preventing vein graft atherosclerosis. Because helper-dependent adenovirus (HDAd) efficiently transduces grafted veins and confers long-term transgene expression, HDAd is an excellent candidate for delivery of vein graft-targeted gene therapy. We developed a model of vein graft atherosclerosis in fat-fed rabbits and demonstrated long-term (≥20 weeks) persistence of HDAd genomes after graft transduction. This model enables quantitation of vein graft hemodynamics, wall structure, lipid accumulation, cellularity, vector persistence, and inflammatory markers on a single graft. Time-course experiments identified 12 weeks after transduction as an optimal time to measure efficacy of gene therapy on the critical variables of lipid and macrophage accumulation. We also used chow-fed rabbits to test whether HDAd infusion in vein grafts promotes intimal growth and inflammation. HDAd did not increase intimal growth, but had moderate-yet significant-pro-inflammatory effects. The vein graft atherosclerosis model will be useful for testing HDAd-mediated gene therapy; however, pro-inflammatory effects of HdAd remain a concern in developing HDAd as a therapy for vein graft disease.

A Rabbit Model for Testing Helper-Dependent Adenovirus-Mediated Gene Therapy for Vein Graft Atherosclerosis

Directory of Open Access Journals (Sweden)

Lianxiang Bi

2017-12-01

Full Text Available Coronary artery bypass vein grafts are a mainstay of therapy for human atherosclerosis. Unfortunately, the long-term patency of vein grafts is limited by accelerated atherosclerosis. Gene therapy, directed at the vein graft wall, is a promising approach for preventing vein graft atherosclerosis. Because helper-dependent adenovirus (HDAd efficiently transduces grafted veins and confers long-term transgene expression, HDAd is an excellent candidate for delivery of vein graft-targeted gene therapy. We developed a model of vein graft atherosclerosis in fat-fed rabbits and demonstrated long-term (≥20 weeks persistence of HDAd genomes after graft transduction. This model enables quantitation of vein graft hemodynamics, wall structure, lipid accumulation, cellularity, vector persistence, and inflammatory markers on a single graft. Time-course experiments identified 12 weeks after transduction as an optimal time to measure efficacy of gene therapy on the critical variables of lipid and macrophage accumulation. We also used chow-fed rabbits to test whether HDAd infusion in vein grafts promotes intimal growth and inflammation. HDAd did not increase intimal growth, but had moderate—yet significant—pro-inflammatory effects. The vein graft atherosclerosis model will be useful for testing HDAd-mediated gene therapy; however, pro-inflammatory effects of HdAd remain a concern in developing HDAd as a therapy for vein graft disease.

Surgical experience with arteriovenous malformations of the brain

International Nuclear Information System (INIS)

Stein, B.M.

1984-01-01

Personal experience with the treatment of 200 arteriovenous malformations of the brain seen during the past decade is presented. One hundred and twenty of these patients underwent surgery, with a mortality of 1,7%. The morbidity rate of 10% includes cases of hemianopia after occipital malformations had been removed. Significant morbidity, including aphasia, hemiparesis and hemisensory loss, occurred in under 10% of cases. Computerized tomography plays an important role in determining the relationships of the arteriovenous malformations to associated structures such as the ventricular system

Emergency hepatectomy for hepatic arteriovenous malformation combined with pulmonary hypertension in an infant

Directory of Open Access Journals (Sweden)

Naruhiko Murase

2015-12-01

Full Text Available Patients with hepatic arteriovenous malformations rarely present with pulmonary hypertension. We report the case of a 3-month-old boy who developed severe pulmonary hypertension due to a hepatic arteriovenous malformation. The use of pulmonary vasodilators to treat the patient's pulmonary hypertension worsened his high-output heart failure. This is the first case in which emergency hepatectomy rescued a patient with hepatic arteriovenous malformations who developed pulmonary hypertension.

Ileocolic Arteriovenous Fistula with Superior Mesenteric Vein Aneurism: Endovascular Treatment

International Nuclear Information System (INIS)

Gregorio, Miguel Angel de; Gimeno, Maria Jose; Medrano, Joaquin; Schoenholz, Caudio; Rodriguez, Juan; D'Agostino, Horacio

2004-01-01

We report a case of a venous aneurysm secondary to an acquired ileocolic arteriovenous fistula in a 64-year-old woman with recurrent abdominal pain and history of appendectomy. The aneurysm was diagnosed by ultrasound and computed tomography. Angiography showed an arteriovenous fistula between ileocolic branches of the superior mesenteric artery and vein. This vascular abnormality was successfully treated with coil embolization

Cutaneous blood flow rate in areas with and without arteriovenous anastomoses during exercise

DEFF Research Database (Denmark)

Midttun, M.; Sejrsen, Per

1998-01-01

Arteriovenous anastomoses, capillaries, cutaneous bllod flow rate, exercise, finger blood flow, skin blood flow......Arteriovenous anastomoses, capillaries, cutaneous bllod flow rate, exercise, finger blood flow, skin blood flow...

Relative risk of hemorrhage during pregnancy in patients with brain arteriovenous malformations

NARCIS (Netherlands)

van Beijnum, Janneke; Wilkinson, Tim; Whitaker, Heather J.; van der Bom, Johanna G.; Algra, Ale; Vandertop, W. Peter; van den Berg, René; Brouwer, Patrick A.; Rinkel, Gabriël Je; Kappelle, L. Jaap; Al-Shahi Salman, Rustam; Klijn, Catharina Jm

2017-01-01

Background It is unclear whether the risk of bleeding from brain arteriovenous malformations is higher during pregnancy, delivery, or puerperium. We compared occurrence of brain arteriovenous malformation hemorrhage in women during this period with occurrence of hemorrhage outside this period during

Establishment of a rat and guinea pig aortic interposition graft model reveals model-specific patterns of intimal hyperplasia.

Science.gov (United States)

Gregory, Elaine K; Vercammen, Janet M; Flynn, Megan E; Kibbe, Melina R

2016-12-01

Although the aortic interposition bypass model has been widely used to evaluate biomaterials for bypass grafting, there is no comprehensive description of the procedure or of the distribution of intimal hyperplasia that results. The objectives of this study were to (1) review and summarize approaches of aortic interposition grafting in animal models, (2) determine the pertinent anatomy for this procedure, (3) validate this model in the rat and guinea pig, and (4) compare the distribution of intimal hyperplasia that develops in each species. A literature search was performed in PubMed from 1980 to the present to analyze the use of anesthesia, anticoagulation, antiplatelet agents, graft material, suture, and anastomotic techniques. Using 10-week-old male Sprague-Dawley rats and Hartley guinea pigs, we established pertinent aortic anatomy, developed comparable models, and assessed complications for each model. At 30 days, the graft and associated aorta were explanted, intimal formation was assessed morphometrically, and cellularity was assessed via nuclear counting. We reviewed 30 articles and summarized the pertinent procedural findings. Upon establishing both animal models, key anatomic differences between the species that affect this model were noted. Guinea pigs have a much larger cecum, increased retroperitoneal fat, and lack the iliolumbar vessels compared with the rat. Surgical outcomes for the rat model included a 53% technical success rate and a 32% technical error rate. Surgical outcomes for the guinea pig model included a 69% technical success rate and a 31% technical error rate. These two species demonstrated unique distribution of intimal hyperplasia at 30 days. Intimal hyperplasia in the rat model was greatest at two areas, the proximal graft (5400 μm 2 ; P guinea pig model developed similar intimal hyperplasia throughout the graft (4500-5100 μm 2 ; P guinea pig, and describe a unique distribution of intimal formation that results in both species

Endovascular repair of arterial iliac vessel wall lesions with a self-expandable nitinol stent graft system.

Directory of Open Access Journals (Sweden)

Birger Mensel

Full Text Available To assess the therapeutic outcome after endovascular repair of iliac arterial lesions (IALs using a self-expandable Nitinol stent graft system.Between July 2006 and March 2013, 16 patients (13 males, mean age: 68 years with a self-expandable Nitinol stent graft. A total of 19 lesions were treated: nine true aneurysms, two anastomotic aneurysms, two dissections, one arteriovenous fistula, two type 1B endoleaks after endovascular aneurysm repair, one pseudoaneurysm, and two perforations after angioplasty. Pre-, intra-, and postinterventional imaging studies and the medical records were analyzed for technical and clinical success and postinterventional complications.The primary technical and clinical success rate was 81.3% (13/16 patients and 75.0% (12/16, respectively. Two patients had technical failure due to persistent type 1A endoleak and another patient due to acute stent graft thrombosis. One patient showed severe stent graft kinking on the first postinterventional day. In two patients, a second intervention was performed. The secondary technical and clinical success rate was 87.5% (14/16 and 93.8% (15/16. The minor complication rate was 6.3% (patient with painful hematoma at the access site. The major complication rate was 6.3% (patient with ipsilateral deep vein thrombosis. During median follow-up of 22.4 months, an infection of the aneurysm sac in one patient and a stent graft thrombosis in another patient were observed.Endovascular repair of various IALs with a self-expandable Nitinol stent graft is safe and effective.

Prevalence of brain arteriovenous malformations in first-degree relatives of patients with a brain arteriovenous malformation

NARCIS (Netherlands)

van Beijnum, Janneke; van der Worp, H. Bart; Algra, Ale; Vandertop, W. Peter; van den Berg, René; Brouwer, Patrick A.; van der Sprenkel, Jan Willem Berkelbach; Kappelle, L. Jaap; Rinkel, Gabriël J. E.; Klijn, Catharina J. M.

2014-01-01

It is uncertain whether familial occurrence of brain arteriovenous malformations (BAVMs) represents coincidental aggregation or a shared familial risk factor. We aimed to compare the prevalence of BAVMs in first-degree relatives (FDRs) of patients with BAVM and the prevalence in the general

Spontane abdominale arteriovenøse fistler

DEFF Research Database (Denmark)

Flarup, S; Lindholt, Jes Sanddal

1997-01-01

Spontaneous arteriovenous fistulas between major abdominal vessels (AAVF) complicates about 1% of abdominal aortic aneurysms. AAVF produces severe circulatory disturbances with high operative mortality. Preoperative diagnosis is important but difficult due to the varied nature of presentation. Fo...

Maxillary reconstruction with a double-barrel osteocutaneous fibular flap and arteriovenous saphenous loop after a globe-sparing total maxillectomy-A Case Report.

Science.gov (United States)

Chen, Szu-Han; Hung, Kuo-Shu; Lee, Yao-Chou

2017-05-01

Maxillary reconstruction using titanium mesh or bone grafts can invite unwanted complications, such as graft resorption, infection, and mesh exposure, especially for patients who require postoperative radiotherapy. Here, we reported a 58-year-old male patient who was diagnosed with maxillary sinus squamous cell carcinoma. The patient received cancer ablation by a globe-sparing total maxillectomy and was immediately reconstructed with a double-barrel osteocutaneous fibular flap to simultaneously restore the alveolar ridge, orbital support, and oro-sinonasal separation. The short pedicle length inherent in the double-barrel design of the fibular flap and the depletion of healthy recipient vessels in the midface after cancer ablation were overcome by creating an arteriovenous saphenous loop in the neck region. Though there was venous congestion on postoperative day 2, the postoperative recovery was uneventful after the revision of the venous anastomoses. During the 6-months follow-up, the outcome was functionally and aesthetically satisfactory. We believe that the double-barrel fibular osteocutaneous flap, which avoids using titanium mesh and bone grafts, may be a viable reconstructive option in cancer patients with globe-sparing total maxillectomy defects, especially for those who require postoperative radiotherapy. © 2015 Wiley Periodicals, Inc. Microsurgery 37:334-338, 2017. © 2015 Wiley Periodicals, Inc.

Modeling and optimization aspects of radiation induced grafting of 4-vinylpyridene onto partially fluorinated films

International Nuclear Information System (INIS)

Nasef, Mohamed Mahmoud; Ahmad Ali, Amgad; Saidi, Hamdani; Ahmad, Arshad

2014-01-01

Modeling and optimization aspects of radiation induced grafting (RIG) of 4-vinylpyridine (4-VP) onto partially fluorinated polymers such as poly(ethylene-co-tetrafluoroethene) (ETFE) and poly(vinylidene fluoride) (PVDF) films were comparatively investigated using response surface method (RSM). The effects of independent parameters: absorbed dose, monomer concentration, grafting time and reaction temperature on the response, grafting yield (GY) were correlated through two quadratic models. The results of this work confirm that RSM is a reliable tool not only for optimization of the reaction parameters and prediction of GY in RIG processes, but also for the reduction of the number of the experiments, monomer consumption and absorbed dose leading to an improvement of the overall reaction cost. - Highlights: • Comparative study of radiation induced grafting of 4-VP onto PVDF and ETFE films. • Optimization of reaction parameters for both grafting systems was made using RSM. • Single factor design for both grafting systems was used as a reference. • Two quadratic regression models were developed for prediction of grafting yield. • RSM is an effective tool for handling grafting reactions under different conditions

Apneic oxygenation combined with extracorporeal arteriovenous carbon dioxide removal provides sufficient gas exchange in experimental lung injury

DEFF Research Database (Denmark)

Nielsen, Niels Dalsgaard; Kjærgaard, Benedict; Nielsen, Jakob Koefoed

In this porcine lung injury model, apneic oxygenation with arteriovenous CO2 removal provided sufficient gas exchange and stable hemodynamics, indicating that the method might have a potential in the treatment of severe ARDS.   Acknowledgements The membrane lungs were kindly provided by Novalung GmbH, Germany.......Background and aim of study We hypothesized that continuous high airway pressure without ventilatory movements (apneic oxygenation), using an open lung approach, combined with extracorporeal, pumpless, arterio-venous, carbon dioxide (CO2) removal would provide adequate gas exchange in acute lung...

Models for formation of macroheterogeneous structure in radiation-grafted polymers

International Nuclear Information System (INIS)

Babkin, I.Yu.; Burukhin, S.B.; Maksimov, A.F.

1994-01-01

Mathematical models, which describe the formation of grafted polymer layer with respect to variations in sorption and kinetic characteristics due to the changes in composition of the modified polymer and grafted polymer under variable boundary conditions were obtained. The influence of heat effect of polymerization reaction on concentration profiles was estimated. Taking into account the nonlinear diffusion kinetics, the conditions providing diffuse and step profiles of concentration of grafted polymer in polymer matrix were revealed. Step concentration profiles were shown to be associated with a nonlinear dependence of diffusion and kinetic parameters of polymerization on the composition of modified polymer. 22 refs.; 11 figs.; 2 tabs

Combined spinal intramedullary arteriovenous malformation and lipomyelomeningocele

Energy Technology Data Exchange (ETDEWEB)

Weon, Y.C.; Roh, H.G.; Byun, H.S. [Samsung Medical Center, Sungkyunkwan University School of Medicine, Department of Radiology, Seoul (Korea); Chung, J.I. [Medimoa Hospital, Department of Radiology, Seoul (Korea); Eoh, W. [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea)

2005-10-01

Combined spinal arteriovenous malformation and lipomyelomeningocele are extremely rare. We present a rare combined case of a lipomyelomeningocele with an intramedullary arteriovenous malformation (AVM) occurred at the L3-L4 level in a 30-year-old man who suffered from low back pain radiating to the lower extremities, dysuria, and frequency for 5 years. The MR studies showed an intradural mass with high-signal intensity on both T1-weighted and T2-weighted images, intermingled with multiple signal-void structures. The mass extended extradurally toward a subcutaneously forming fatty mass on the patient's back. Spinal angiography showed an AVM supplied by the radiculopial branches of the lumbar arteries and drained by tortuous, dilated, perimedullary veins. Endovascular embolization and surgical resection were performed. (orig.)

Experimental Models Used in Fat Grafting Research for Volume Augmentation in Soft Tissue Reconstruction

Directory of Open Access Journals (Sweden)

Jorge Lujan-Hernandez

2017-09-01

Full Text Available As the popularity of fat grafting research increases, animal models are being used as the source of pre-clinical experimental information for discovery and to enhance techniques. To date, animal models used in this research have not been compared to provide a standardized model. We analyzed publications from 1968–2015 to compare published accounts of animal models in fat grafting research. Data collected included: species used, graft characteristics (donor tissue, recipient area, amount injected, injection technique, time of sacrifice and quantification methods. Mice were most commonly used (56% of studies, with the “athymic nude” strain utilized most frequently (44%. Autologous fat was the most common source of grafted tissue (52%. Subcutaneous dorsum was the most common recipient site (51%. On average, 0.80±0.60 mL of fat was grafted. A single bolus technique was used in 57% of studies. Fat volume assessment was typically completed at the end of the study, occurring at less than 1 week to one year. Graft volume was quantified by weight (63%, usually in conjunction with another analysis. The results demonstrate the current heterogeneity of animal models in this research. We propose that the research community reach a consensus to allow better comparison of techniques and results. One example is the model used in our laboratory and others; this model is described in detail. Eventually, larger animal models may better translate to the human condition but, given increased financial costs and animal facility capability, should be explored when data obtained from small animal studies is exhausted or inconclusive.

Reproduction of superior sagittal sinus animal model by bypass transplantation of biomaterial graft

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Qing-yong LUO

2011-03-01

Full Text Available Objective To establish the beagles model of superior sagittal sinus bypass graft,and explore the feasibility of reconstruction of superior sagittal sinus with biomaterials using this model.Methods Eight adult male beagles(weight: 12.5-22.0kg were involved in the present study.The superior sagittal sinus was exposed and blocked via bone window,and then anastomosed side-to-end to the biomaterial graft under the dedicated microscope of neurosurgery surgery,expectant treatment such as anti-inflammatory was given for the animals.The digital subtraction venography(DSV and color Doppler flow imaging(CDFI of superior sagittal sinus were performed in 1,2,4 and 8 weeks after the operation.Eight weeks after the operation,all the animals were sacrificed and the material graft was examined histologically.Results The DSV and CDFI of superior sagittal sinus showed that the stomas of 2 beagles were with slight stenosis and high flow velocity,of 1 beagle with small leakage and low flow velocity,while of other 5 beagles were normal.The histological examination showed endothelial cells were growing on the graft and superior sagittal sinus,and crawling toward the lumen of graft 8 weeks after the operation.Conclusion The beagles model of superior sagittal sinus bypass graft was established successfully.The short-term effect of the model was satisfactory,while further work should be performed to determine the long-term effects.

Surgical management of dural arteriovenous fistulas with transosseous arterial feeders involving the jugular bulb.

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Tirakotai, W; Benes, L; Kappus, C; Sure, U; Farhoud, A; Bien, S; Bertalanffy, H

2007-01-01

Dural arteriovenous fistulas located in the vicinity of the jugular foramen are complex vascular malformations and belong to the most challenging skull base lesions to treat. The authors comprehensively analyze multiple features in a series of dural arteriovenous fistulas with transosseous arterial feeders involving the jugular bulb. Four patients who underwent surgery via the transcondylar approach to treat dural arteriovenous fistulas around the jugular foramen were retrospectively reviewed. Previously, endovascular treatment was attempted in all patients. The success of the surgical treatment was examined with postoperative angiography. Complete obliteration of the dural arteriovenous fistulas (DAVFs) was achieved in three patients, and significant flow reduction in one individual. All patients had a good postoperative outcome, and only one experienced mild hypoglossal nerve palsy. Despite extensive bone drilling, an occipitocervical fusion was necessary in only one patient with bilateral lesions. The use of an individually tailored transcondylar approach to treat dural arteriovenous fistulas at the region of the jugular foramen is most effective. This approach allows for complete obliteration of the connecting arterial feeders, and removal of bony structures containing pathological vessels.

Antecedent thermal injury worsens split-thickness skin graft quality: A clinically relevant porcine model of full-thickness burn, excision and grafting.

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Carlsson, Anders H; Rose, Lloyd F; Fletcher, John L; Wu, Jesse C; Leung, Kai P; Chan, Rodney K

2017-02-01

Current standard of care for full-thickness burn is excision followed by autologous split-thickness skin graft placement. Skin grafts are also frequently used to cover surgical wounds not amenable to linear closure. While all grafts have potential to contract, clinical observation suggests that antecedent thermal injury worsens contraction and impairs functional and aesthetic outcomes. This study evaluates the impact of antecedent full-thickness burn on split-thickness skin graft scar outcomes and the potential mediating factors. Full-thickness contact burns (100°C, 30s) were created on the backs of anesthetized female Yorkshire Pigs. After seven days, burn eschar was tangentially excised and covered with 12/1000th inch (300μm) split-thickness skin graft. For comparison, unburned wounds were created by sharp excision to fat before graft application. From 7 to 120days post-grafting, planimetric measurements, digital imaging and biopsies for histology, immunohistochemistry and gene expression were obtained. At 120days post-grafting, the Observer Scar Assessment Scale, colorimetry, contour analysis and optical graft height assessments were performed. Twenty-nine porcine wounds were analyzed. All measured metrics of clinical skin quality were significantly worse (pskin graft quality, likely by multiple mechanisms including burn-related inflammation, microscopically inadequate excision, and dysregulation of tissue remodeling. A valid, reliable, clinically relevant model of full-thickness burn, excision and skin replacement therapy has been demonstrated. Future research to enhance quality of skin replacement therapies should be directed toward modulation of inflammation and assessments for complete excision. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Development of an abdominal aortic aneurysm model for stent-graft insertion

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Kim, Tae Hyung; Lee, Jong Heon; Shin, Dong Ik; Sung, Kyu Bo; Ko, Gi Young; Lim, Jin Oh [College of Medicine, Univ. of Ulsan, Seoul (Korea, Republic of); Kim, Si Hoon [S and G Biotech Research Institute, Seoul (Korea, Republic of)

2002-03-01

To determine the efficacy of an abdominal aortic aneurysm model for stent-graft placement. The model consists of two parts, the heart and the vascular system. A peristaltic pump and a solenoid valve were used to simulate a pulsatile flow from the heart. A ball-shaped piece of clay was placed inside a square box and liquid silicone was poured. After the silicone was formed, the clay was removed and a silicone tube was used to connect the heart model and the aneurysm model. The silicone tube was also used to simulate the iliac arteries and one end of the artery was clampled and the other one was extended to water bath. Water at 37 .deg. C was circulated through the model, and the pressure at the thoracic aorta, aneurysm and iliac artery was measured with the outlet valve opening at 25, 50, and 100% before and after stent-graft placement. The liquid pressure measurements were 253/252, 271/162 and 264/166 mmHg at the thoracic aorta, aneurysm and iliac artery, respectively, when the outlet was 100% open. They were 173/121, 145/99, 145/106 mmHg when the outlet was 50% open, and 35/28, 61/44, 24/22 mmHg when it was 25% open. After placement of the stent-graft, the pressure measurements were 170/128, and 167/128 mmHg, respectively. Since it was easy to produce, the model was useful for in-vitro stent-graft testing, and a wide range of pressure could be applied.

Angiographic treatment of the arteriovenous malformation occurred after caesarean section

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Selim Büyükkurt

2009-03-01

Full Text Available INTRODUCTION: Uterine arteriovenous malformations are classified as acquired or congenital. Caesarean section which is performed more frequently on nowadays, uterine curettage and other uterine surgeries are the most common causes of the acquired arteriovenous malformations. CASE: Twenty-two years old woman delivered her second child by caesarean section, due to history of caesarean section, was admitted with complaint of profuse vaginal bleeding 15 days after the surgery. She demonstrated the clinical features of the hypovolemic shock. At first she treated with four units of red blood suspension, two units of fresh frozen plasma and rapid infusion of the fluids. On endometrial curettage only blood and coagulum were obtained. The bleeding could only be controlled by the internal pressure of the 18 F Foley catheter. Doppler analyze of the uterus revealed a vascular malformation signifying a turbulent flow pattern with low pressure and high flow rate. A unilateral uterine artery embolization was performed her and her menstruel cycles are resumed at the fifth month of the puerperium. DISCUSSION: The clinical presentation of the uterine arteriovenous malformations depends on the localization and the dimensions of the malformation. The uterine arteriovenous malformation should be kept in mind in cases of late occurrence vaginal bleeding unresponsive to the uterotonic medications, especially in a woman with previous history of uterine damage, such as curettage or caesarean section.

The value of pre-discharge Duplex scanning in infrainguinal graft surveillance.

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Wilson, Y G; Davies, A H; Currie, I C; McGrath, C; Morgan, M; Baird, R N; Lamont, P M

1995-08-01

Protocols and criteria for Duplex-based graft surveillance programmes (GS) vary widely as to the optimum regimens for maximising detection of "at risk" grafts. Few centres recommend starting GS before discharge. The aim of this study was to audit our experience with respect to early scanning. Vascular Studies Unit, Bristol Royal Infirmary. The records of 123 patients entering GS from January 1992 were reviewed. Patients were scanned at 1 week, 6 weeks and 3, 6, 9 and 12 months post-bypass. Haemodynamic criteria used were a peak mean velocity (PMV) less than 45 cm/s and a focal velocity disturbance with a V2/V1 ratio of 1.5 or more. Forty-six abnormalities (37% detection rate) were identified on scans within one week. In all cases, on-table completion studies with either arteriography and/or flow measurements had failed to identify the anomalies subsequently detected by Duplex. At 1 week, six grafts had occluded, 27 had a focal PMV increase (mean V2/V1 ratio: 2.6; range 1.5-4.3), four had low flow velocities, four had arteriovenous fistulae, one contained mobile thrombus, two had retained cusps and two had hamstring entrapment. Of 40 patent, but compromised grafts, 18 warranted immediate investigation. Of the 27 patients with velocity disturbances on Duplex, 25 were simply observed but, eight have since required intervention for definitive stenoses at these sites which, in retrospect, were evident within the first postoperative week. Pre-discharge scanning is a useful modality for detecting technical problems. Intrinsic graft abnormalities, possibly the sites of future definitive stenoses, have been visualised even at 1 week and once identified, can be more closely scrutinised thereafter. Pre-discharge colour Duplex is recommended as standard practice for quality control after infrainguinal bypass.

Management of patients with brain arteriovenous malformations

International Nuclear Information System (INIS)

Soederman, Michael; Andersson, Tommy; Karlsson, Bengt; Wallace, M. Christopher; Edner, Goeran

2003-01-01

Arteriovenous malformations (AVMs) of the brain, which are probably genetically determined, are errors in the development of the vasculature that, together with the effects of blood flow, may lead to a focal arteriovenous shunt. Clinically, the adult patient may present with acute or chronic neurological symptoms--fixed or unstable--such as deficits, seizures or headache. Sometimes the lesion is an incidental finding. In about half of the patients, the revealing event is an intracranial haemorrhage. The prevalence of AVM in the western world is probably 10 ml could benefit from targeted partial embolisation followed by radiosurgery or surgery, depending on the angioarchitecture; and (IV) AVMs >20 ml nidus volume usually have a high treatment risk with any treatment modality and are not obvious targets for treatment at all

Vascular access for home haemodialysis.

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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.

Vector Volume Flow in Arteriovenous Fistulas

DEFF Research Database (Denmark)

Hansen, Peter Møller; Heerwagen, Søren; Pedersen, Mads Møller

2013-01-01

, but is very challenging due to the angle dependency of the Doppler technique and the anatomy of the fistula. The angle independent vector ultrasound technique Transverse Oscillation provides a new and more intuitive way to measure volume flow in an arteriovenous fistula. In this paper the Transverse...

Atypical MRI features in soft-tissue arteriovenous malformation: a novel imaging appearance with radiologic-pathologic correlation

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Patel, Anand S. [University of California, San Francisco, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); University of California, San Francisco, Department of Interventional Radiology, San Francisco, CA (United States); Schulman, Joshua M.; Ruben, Beth S. [University of California, San Francisco, Departments of Pathology and Dermatology, San Francisco, CA (United States); Hoffman, William Y. [University of California, San Francisco, Department of Plastic Surgery, Birthmarks and Vascular Anomalies Clinic, San Francisco, CA (United States); Dowd, Christopher F. [University of California, San Francisco, Department of Interventional Neuroradiology, Birthmarks and Vascular Anomalies Clinic, San Francisco, CA (United States); Frieden, Ilona J. [University of California, San Francisco, Department of Dermatology, Birthmarks and Vascular Anomalies Clinic, San Francisco, CA (United States); Hess, Christopher P. [University of California, San Francisco, Department of Neuroradiology, Birthmarks and Vascular Anomalies Clinic, San Francisco, CA (United States)

2015-09-15

The absence of a discrete mass, surrounding signal abnormality and solid enhancement are imaging features that have traditionally been used to differentiate soft-tissue arteriovenous malformations from vascular tumors on MRI. We have observed that these findings are not uncommon in arteriovenous malformations, which may lead to misdiagnosis or inappropriate treatment. To estimate the frequency of atypical MRI features in soft-tissue arteriovenous malformations and assess their relationship to lesion size, location, tissue type involved and vascular architecture. Medical records, MRI and histopathology were reviewed in consecutive patients with soft-tissue arteriovenous malformations in a multidisciplinary vascular anomalies clinic. Arteriovenous malformations were divided into those with and without atypical MRI findings (perilesional T2 signal abnormality, enhancement and/or a soft-tissue mass). Lesion location, size, tissue involved and vascular architecture were also compared between groups. Tissue stains were reviewed in available biopsy or resection specimens to assess relationships between MRI findings and histopathology. Thirty patients with treatment-naive arteriovenous malformations were included. Fifteen lesions demonstrated atypical MRI. There was no difference in age, gender, lesion size or involved body part between the groups. However, more than half of the atypical lesions demonstrated multicompartmental involvement, and tiny intralesional flow voids were more common in atypical arteriovenous malformations. Histopathology also differed in atypical cases, showing densely packed endothelial cells with connective tissue architectural distortion and edema. Arteriovenous malformations may exhibit features of a vascular tumor on MRI, particularly when multicompartmental and/or containing tiny internal vessels. These features are important to consider in suspected fast-flow vascular malformations and may have implications with respect to their treatment

Development of three-dimensional brain arteriovenous malformation model for patient communication and young neurosurgeon education.

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Dong, Mengqi; Chen, Guangzhong; Qin, Kun; Ding, Xiaowen; Zhou, Dong; Peng, Chao; Zeng, Shaojian; Deng, Xianming

2018-01-15

Rapid prototyping technology is used to fabricate three-dimensional (3D) brain arteriovenous malformation (AVM) models and facilitate presurgical patient communication and medical education for young surgeons. Two intracranial AVM cases were selected for this study. Using 3D CT angiography or 3D rotational angiography images, the brain AVM models were reconstructed on personal computer and the rapid prototyping process was completed using a 3D printer. The size and morphology of the models were compared to brain digital subtraction arteriography of the same patients. 3D brain AVM models were used for preoperative patient communication and young neurosurgeon education. Two brain AVM models were successfully produced. By neurosurgeons' evaluation, the printed models have high fidelity with the actual brain AVM structures of the patients. The patient responded positively toward the brain AVM model specific to himself. Twenty surgical residents from residency programs tested the brain AVM models and provided positive feedback on their usefulness as educational tool and resemblance to real brain AVM structures. Patient-specific 3D printed models of brain AVM can be constructed with high fidelity. 3D printed brain AVM models are proved to be helpful in preoperative patient consultation, surgical planning and resident training.

Effect of skin graft thickness on scar development in a porcine burn model.

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DeBruler, Danielle M; Blackstone, Britani N; McFarland, Kevin L; Baumann, Molly E; Supp, Dorothy M; Bailey, J Kevin; Powell, Heather M

2018-06-01

Animal models provide a way to investigate scar therapies in a controlled environment. It is necessary to produce uniform, reproducible scars with high anatomic and biologic similarity to human scars to better evaluate the efficacy of treatment strategies and to develop new treatments. In this study, scar development and maturation were assessed in a porcine full-thickness burn model with immediate excision and split-thickness autograft coverage. Red Duroc pigs were treated with split-thickness autografts of varying thickness: 0.026in. ("thin") or 0.058in. ("thick"). Additionally, the thin skin grafts were meshed and expanded at 1:1.5 or 1:4 to evaluate the role of skin expansion in scar formation. Overall, the burn-excise-autograft model resulted in thick, raised scars. Treatment with thick split-thickness skin grafts resulted in less contraction and reduced scarring as well as improved biomechanics. Thin skin autograft expansion at a 1:4 ratio tended to result in scars that contracted more with increased scar height compared to the 1:1.5 expansion ratio. All treatment groups showed Matrix Metalloproteinase 2 (MMP2) and Transforming Growth Factor β1 (TGF-β1) expression that increased over time and peaked 4 weeks after grafting. Burns treated with thick split-thickness grafts showed decreased expression of pro-inflammatory genes 1 week after grafting, including insulin-like growth factor 1 (IGF-1) and TGF-β1, compared to wounds treated with thin split-thickness grafts. Overall, the burn-excise-autograft model using split-thickness autograft meshed and expanded to 1:1.5 or 1:4, resulted in thick, raised scars similar in appearance and structure to human hypertrophic scars. This model can be used in future studies to study burn treatment outcomes and new therapies. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

Modeling conduction in host-graft interactions between stem cell grafts and cardiomyocytes.

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Chen, Michael Q; Yu, Jin; Whittington, R Hollis; Wu, Joseph C; Kovacs, Gregory T A; Giovangrandi, Laurent

2009-01-01

Cell therapy has recently made great strides towards aiding heart failure. However, while transplanted cells may electromechanically integrate into host tissue, there may not be a uniform propagation of a depolarization wave between the heterogeneous tissue boundaries. A model using microelectrode array technology that maps the electrical interactions between host and graft tissues in co-culture is presented and sheds light on the effects of having a mismatch of conduction properties at the boundary. Skeletal myoblasts co-cultured with cardiomyocytes demonstrated that conduction velocity significantly decreases at the boundary despite electromechanical coupling. In an attempt to improve the uniformity of conduction with host cells, differentiating human embryonic stem cells (hESC) were used in co-culture. Over the course of four to seven days, synchronous electrical activity was observed at the hESC boundary, implying differentiation and integration. Activity did not extend far past the boundary, and conduction velocity was significantly greater than that of the host tissue, implying the need for other external measures to properly match the conduction properties between host and graft tissue.

Arteriovenous Malformation Detected by Small Bowel Endoscopy

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Takaaki Fujii

2014-10-01

Full Text Available Gastrointestinal bleeding that originates in the small intestine is often difficult to diagnose. When successful diagnosis reveals a lesion that can be localized preoperatively, the laparoscopic approach is an appropriate and beneficial treatment modality for small bowel resection. A 69-year-old man presented with a 6-month history of gastrointestinal bleeding and symptomatic transfusion-dependent anemia. Upper and lower endoscopy were normal. Double-balloon endoscopy established the source of the bleeding as a 0.5-cm polypoid mass appearing as a submucosal tumor with redness and pulsation in the lower ileum, suggesting a vascular lesion. Laparoscopic small bowel resection was successful in removing the mass in the ileum. Histological evaluation of the mass revealed an arteriovenous malformation. Preoperative small bowel endoscopy can be useful for diagnosing the cause and localization of arteriovenous malformation in the small intestine.

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

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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.

Lower Limb Arteriovenous Communications in Diabetes Mellitus: A Potential Reason for Aggravation of Ischemic Symptoms

International Nuclear Information System (INIS)

Hamady, Mohamad S.; Yu, Dominic F.; Sayer, Gabriel L.; Edmonds, Michael E.; Walters, Huw L.; Sidhu, Paul S.

2006-01-01

The aim of this study was to assess the prevalence and to evaluate the clinical associations of arteriovenous communications in patients with diabetes mellitus (DM) and lower limb peripheral arterial ischemia. Peripheral arteriography of DM patients from an eight-year period (1993-2000) was evaluated retrospectively by two observers. The presence of arteriovenous communications, defined as occurring without evidence of a preceding precipitating event, and the distribution and severity of the vascular disease were evaluated. The type (non-insulin-dependent DM or insulin-dependent DM) and the duration of the DM, the presenting symptoms, and the presence of a peripheral neuropathy were documented by a review of the clinical records. A total of 348 arteriography studies in 285 DM patients were evaluated (duration of DM: median, 16 years; range, 7-42 years); an arteriovenous communication was present in 14/285 patients (4.9%), 9 male and 5 female (median age, 71 years; range, 17-84 years). Symptoms were those of a peripheral leg ulcer (n = 11), claudication (n = 3), and gangrene (n = 1), with symptoms ipsilateral to the side of the arteriovenous communication in 13/14 patients. The sites of the arteriovenous communications were infra popliteal (n = 7), popliteal (n = 3), superficial femoral artery (n = 3), and common femoral artery (n = 1). Features of a peripheral neuropathy were found in 12/14 and ipsilateral to the side of the communication in 11/12. Arteriovenous communications in the peripheral femoral arterial system of patients with DM is an uncommon finding. Although not proven in the current study, arteriovenous communications might be associated with more severe symptoms than that attributable to the underlying vascular disease alone

Vertebral Arteriovenous Fistula Presenting as Cervical Myelopathy: A Rapid Recovery with Balloon Embolization

International Nuclear Information System (INIS)

Modi, Manish; Bapuraj, J. Rajiv; Lal, Anupam; Prabhakar, S.; Khandelwal, N.

2010-01-01

A 24-year-old male presented with progressive cervical myelopathy of 2 months' duration. Magnetic resonance imaging of the cervical spine and angiography revealed a large arteriovenous fistula arising from the left vertebral artery. The present case highlights the clinical features and dramatic recovery following endovascular balloon occlusion of a giant cervical arteriovenous fistula.

Arteriovenous malformation of the external ear: a clinical assessment with a scoping review of the literature

Directory of Open Access Journals (Sweden)

Shin Hye Kim

Full Text Available Abstract Introduction: Auricular Arteriovenous Malformation of the external ear is a rarely encountered disease; in particular, arteriovenous malformation arising from the auricle, with spontaneous bleeding, has seldom been reported. Objective: In the current study, we report an unusual case of late-onset auricular arteriovenous malformation originating from the posterior auricular artery that was confirmed by computed tomographic angiography. The case was successfully managed by pre-surgical intravascular embolization followed by total lesion excision. Prompted by this case, we also present a scoping review of the literature. Methods: A case of a 60 year-old man with right auricular arteriovenous malformation treated in our tertiary care center, and 52 patients with auricular arteriovenous malformation described in 10 case reports and a retrospective review are presented. Auricular arteriovenous malformation can manifest as swelling of the ear, pulsatile tinnitus, pain, and/or bleeding. On physical examination, a pulsatile swelling and/or a tender mass is evident. When arteriovenous malformation is suspected, the lesions should be visualized using imaging modalities that optimally detect vascular lesions, and managed via embolization, mass excision, or auricular resection. Effectiveness of the various diagnostic methods used and the treatment outcomes were analyzed. Results: Various imaging modalities including Doppler sonography, computed tomographic angiography, magnetic resonance angiography, and/or transfemoral cerebral angiography were used to diagnose 38 cases reported in the literature. In another 15 cases, no imaging was performed; treatment was determined solely by physical examination and auscultation. Of the total of 53 cases, 12 were not treated (their symptoms were merely observed whereas 20 underwent therapeutic embolization. In total, 32 patients, including 1 patient who was not treated and 10 with persistent or aggravated

Prediction of complications in Gamma Knife radiosurgery of arteriovenous malformations

International Nuclear Information System (INIS)

Lax, I.; Karlsson, B.

1996-01-01

The incidence of complications following radiosurgical treatment of arteriovenous malformations (AVM) is presented. A simple relationship exists between average dose and risk of complications, and on this basis a model is presented that gives a qualitatively correct description of this relationship. The parameters of the model have been determined using a clinical material of 862 AVM treatments to give a quantitativley correct description of the risk of complications. The dose-response curve is described by a double-exponential function. An accurate description of the dose-response curve at high dose levels is shown to be very important in radiosurgery. (orig.)

Transmicrocatheter local injection of ethanol to treat hepatocellular carcinoma with high flow arteriovenous shunts

International Nuclear Information System (INIS)

Guan Shouhai; Shan Hong; Jiang Zaibo; Huang Mingsheng; Zhu Kangshun; Li Zhengran; Meng Xiaochun

2002-01-01

Objective: To evaluate the feasibility and clinical effect of embolization therapy in treating the high flow hepatic arteriovenous shunts in hepatocellular carcinoma (HCC) by locally injected ethanol through microcatheter. Methods: Forty-one branches of arteriovenous shunts were treated by local ethanol infusion through microcatheter in 29 patients suffered with HCC. Angiography was performed to observe the embolization effect and influence to non-targeted vessels. Result: Forty-one branches of arteriovenous shunts in 29 patients were injected with ethanol locally. Each single shunt was infused 1-6 times. The dose of ethanol was 2-3 ml per time, and the total dose of ethanol was 2-12 ml. All shunting tracts were embolized, and all non-target vessels were protected fluently. Iodine-oil deposition was well in continued TACE. Their syndromes were improved or disappeared. Conclusion: Transmicrocatheter injection of ethanol could safely and effectively treat the hepatic arteriovenous shunts and make advantages to TACE in HCC

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

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

2009-06-01

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

Quantitative determination of peripheral arterio-venous shunts by means of radioactively labelled microspheres

International Nuclear Information System (INIS)

Friese, K.H.

1981-01-01

In the present work a nuclear method of quantitative measurement of peripheral arterio-venous shunts with a whole-body scanner is standardized. This method, developed at the beginning of the 70s at Tuebingen, stands out in contrast with earlier measuring methods by the application of the theory of quantitative scintiscanning. This means that the scintigram obtained after injection of sup(99m)technetium-labelled human albumin microspheres into an artery before the shunt is corrected for the quantitative shunt calculation by several factors using a computer, to avoid systematic mistakes. For the standardization of the method, 182 scintigrams were taken during model experiments and experiments on animals and human beings. This method, having a deviation of 10% at most, is excellently suited for the quantitative determination of peripheral arterio-venous shunts. Already for a pulmonary activity of 3% a peripheral shunt is proved with 97.5% probability. (orig./MG) [de

Embolization with Gamma Knife Radiosurgery of Giant Intracranial Arteriovenous Malformations.

Science.gov (United States)

Chun, Dong Hyun; Kim, Moo Seong; Kim, Sung Tae; Paeng, Sung Hwa; Jeong, Hae Woong; Lee, Won Hee

2016-01-01

Giant arteriovenous malformations (i.e., those greater than 6 cm maximum diameter or volume > 33 cc) are difficult to treat and often carry higher treatment morbidity and mortality rates. In our study, we reviewed the angiographic results and clinical outcomes for 11 patients with giant arteriovenous malformations who were treated between 1994 and 2012. The patients selected included 9 males (82%) and 2 females (18%). Their presenting symptoms were hemorrhage (n=2; 18%), seizure (n=7; 64%), and headache (n=2; 12%). Nine patients were Spetzler-Martin Grade III, 2 were Spetzler-Martin Grade IV. The mean arteriovenous malformation volume was 41 cc (33-52 cc). The mean age of the patients was 45.1 years (24-57 years) and the mean radiation dose delivered to the margin of the nidus was 14.2 Gy. Ten patients received pre-Gamma Knife radiosurgery embolization and Gamma Knife radiosurgery, 1 patient received pre-Gamma Knife radiosurgery embolization and Gamma Knife radiosurgery twice and the interval between Gamma Knife radiosurgeries was 3 months. The complete obliteration rate following Gamma Knife radiosurgery was 36%, subtotal obliteration ( > 70% decreased size of nidus) was 36%, and partial obliteration was 28%. One patient experienced a small hemorrhage after embolization. Combined embolization and Gamma Knife radiosurgery showed successful obliteration of the arteriovenous malformation nidus. The use of embolization to initially reduce nidus size followed by Gamma Knife radiosurgery improves the treatment results. Repeated Gamma Knife radiosurgery should be a treatment option when there is a small nidus remnant.

[Pulmonary arteriovenous fistula with Rendu-Osler-Weber disease].

Science.gov (United States)

Segawa, Masataka; Touge, Masayoshi; Seki, Kouji; Kusajima, Yoshinori; Saito, Katsuhiko

2012-09-01

A 36-year-old man was admitted to our hospital for examination of a nodular shadow in the left lung. Chest 3-dimensional computed tomography (3D-CT) revealed a pulmonary arteriovenous fistula (PAVF) of 21 mm in diameter composed of the feeding artery (A4) and the draining vein (V4) in the left S4. Abdominal enhanced CT revealed multiple hepatic arteriovenous fistula. Brain CT revealed a cavernous hemangioma in right occipital cerebrum. He had a family history, habitual epistaxis, and oral telangiectasia and was diagnosed as Rendu-Osler-Weber disease (hereditary hemorrhagic telangiectasia:HHT). According to his family history, PAVF was likely to be a risk factor of brain infarction and abscess, and the wedge resection of the lingual lobe was performed to remove PAVF.

Peroneal Arteriovenous Fistula and Pseudoaneurysm: An Unusual Presentation

Directory of Open Access Journals (Sweden)

Kevin C. Ching

2014-01-01

Full Text Available Peroneal artery arteriovenous fistulas and pseudoaneurysms are extremely rare with the majority of reported cases due to penetrating, orthopedic, or iatrogenic trauma. Failure to diagnose this unusual vascular pathology may lead to massive hemorrhage or limb threatening ischemia. We report an interesting case of a 14-year-old male who presented with acute musculoskeletal pain of his lower extremity. Initial radiographs were negative. Further imaging workup revealed a peroneal arteriovenous fistula with a large pseudoaneurysm. After initial endovascular intervention was unsuccessful, the vessels were surgically ligated in the operating room. Pathology revealed papillary endothelial hyperplasia consistent with an aneurysm and later genetic testing was consistent with Ehlers-Danlos syndrome Type IV. This case illustrates an unusual cause of acute atraumatic musculoskeletal pain and uncommon presentation of Ehlers-Danlos syndrome.

Hybrid management of a spontaneous ilio-iliac arteriovenous fistula: a case report

LENUS (Irish Health Repository)

O'Brien, Gavin C

2011-08-22

Abstract Introduction Spontaneous iliac arteriovenous fistulae are a rare clinical entity. Such localized fistulation is usually a result of penetrating traumatic or iatrogenic injury. Clinical presentation can vary greatly but commonly includes back pain, high-output congestive cardiac failure and the presence of an abdominal bruit. Diagnosis, therefore, is often incidental or delayed. Case presentation We report a case of a spontaneous ilio-iliac arteriovenous fistula in a 68-year-old Caucasian man detected following presentation with unilateral claudication and congestive cardiac failure. Following computed tomography evaluation, the fistula was successfully treated with a combined endovascular (aorto-uni-iliac device) and open (femoro-femoral crossover) approach. Conclusion Endovascular surgery has revolutionized the management of such fistulae and we report an interesting case of a high-output iliac arteriovenous fistulae successfully treated with a hybrid vascular approach.

[A vertebral arteriovenous fistula diagnosed by auscultation].

Science.gov (United States)

Iglesias Escalera, G; Diaz-Delgado Peñas, R; Carrasco Marina, M Ll; Maraña Perez, A; Ialeggio, D

2015-01-01

Cervical artery fistulas are rare arteriovenous malformations. The etiology of the vertebral arteriovenous fistulas (AVF) can be traumatic or spontaneous. They tend to be asymptomatic or palpation or continuous vibration in the cervical region. An arteriography is necessary for a definitive diagnosis. The treatment is complete embolization of the fistula. We present the case of a two year-old male, where the mother described it «like a washing machine in his head». On palpation during the physical examination, there was a continuous vibration, and a continuous murmur in left cervical region. A vascular malformation in vertebral region was clinically suspected, and confirmed with angio-MRI and arteriography. AVF are rare in childhood. They should be suspected in the presence of noises, palpation or continuous vibration in the cervical region. Early diagnosis can prevent severe complications in asymptomatic children. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

Indocyanine green videoangiography "in negative": definition and usefulness in intracranial dural arteriovenous fistulae.

Science.gov (United States)

Simal Julián, Juan Antonio; Miranda Lloret, Pablo; Aparici Robles, Fernando; Beltrán Giner, Andrés; Botella Asunción, Carlos

2013-09-01

Indocyanine green videoangiography (IGV) raises important limitations when we use it in vascular pathology, especially in cases with arterialization of the venous system such as arteriovenous malformations and fistulae. Our objective was to provide a simple procedure that overcomes the limitations of conventional IGV. We define IGV in negative (IGV-IN), so-called because, in its first phase, the vessel to analyze is clipped, and we report 3 cases of intracranial dural arteriovenous fistulae treated with this procedure. In 2011, we applied IGV-IN to 3 patients at our center with Borden type III intracranial arteriovenous fistulae. In all 3 cases, IGV-IN enabled both diagnosis and post-dural arteriovenous fistula exclusion control in 1 integrated procedure no longer than 1 minute, requiring only 1 visualization. IGV-IN is an improvement over the conventional IGV method and is able to provide more information in a shorter period of time. It is an intuitive and highly visual procedure, and, more importantly, it is reversible. Studies with larger samples are necessary to determine whether IGV-IN can further reduce the need for postoperative digital subtraction angiography.

Endovascular repair of posttraumatic multiple femoral-femoral and popliteal-popliteal arteriovenous fistula with Viabahn and excluder stent graft

Directory of Open Access Journals (Sweden)

Šarac Momir

2011-01-01

Full Text Available Background. Traumatic arteriovenous (AV fistula is considered to be a pathologic communication between the arterial and venous systems following injury caused mostly by firearms, sharp objects or blasting agents. Almost 50% of all traumatic AV fistulas are localized in the extremities. In making diagnosis, besides injury anamnesis data, clinical image is dominated by palpable thrill and auscultator continual sounds at the site of fistula, extremities edemas, ischemia distally of fistula, pronounced varicose syndrome, and any signs of the right heart load in high-flow fistulas. Case report. We presented a male 32-year-old patient self-injured the region of the right lower and upper leg by shotgun during hunting in 2005. The same day the patient was operated on in a tertiary traumatology health care institution under the diagnosis of vulnus sclopetarium femoris et cruris dex; AV fistula reg popliteae dex; fractura cruris dex. The performed surgery was ligatura AV fistulae; reconstructio a. popliteae cum T-T anastomosis; fasciotomia cruris dex. Postoperatively, in the patient developed a multiple AV fistula of the femoral and popliteal artery and neighboring veins. The patient was two more times operated on for closing the fistula but with no success. Three years later the patient was referred to the Clinic for Vascular Surgery, Military Medical Academy, Belgrade, Serbia. A physical examination on admission showed the right upper leg edema, pronounced varicosities and high thrill, signs of the skin induration and initial ischemia with ulceration in the right lower leg, as well as numerous scars in the inner side of the leg from the previously performed operations. Due to the right heart load there were also present easy getting tired, tachypnoea and tachycardia. CT and contrast angiography verified the presence of multiple traumatic AV fistulas in the surface femoral and popliteal artery and neighboring veins of the highest diameter being 1 cm

Coralline hydroxyapatite bone graft substitutes in a canine metaphyseal defect model: Radiographic-biomechanical correlation

International Nuclear Information System (INIS)

Sartoris, D.J.; Resnick, D.; Holmes, R.E.; Tencer, A.F.; Texas Univ., Dallas; Mooney, V.

1986-01-01

Radiographic and biomechanical assessment of a new type of bone graft substitute derived from reef-building sea coral was performed in a canine metaphyseal defect model. Blocks of this material and autogenous iliac crest graft were implanted, respectively, into the right and left proximal tibial metaphyses of eight dogs. Qualitative and quantitative radiographic evaluation was performed in the immediate postoperative period and at 6 months after surgery. Biomechanical testing was carried out on all grafts following harvest at 6 months, as well as on nonimplanted coralline hydroxyapatite and autogenous iliac cancellous bone. In contrast to autografts, incorporation of coralline implants was characterized by predictable osseous growth and apposition with preservation of intrinsic architecture. Greater percent increase in radiography density, higher ultimate compressive strength, and lower stiffness with incorporation were documented advantages of coralline hydroxyapatite over autogenous graft. Densitometric measurements correlated moderately with strength for both types of graft material (r=0.65). These promising results have important implications to the clinical application of coralline hydroxyapatite bone graft substitutes as an alternative to autogenous grafting. (orig.)

[The use of labelled albumin microspheres in the study of arteriovenous shunting in varicosities of the lower limbs (author's transl)].

Science.gov (United States)

Serise, J M; Le Héron, D; Le Héron, G; Bonnet, A; Busquet, J; Basse-Cathalinat, B; Tingaud, R

1982-01-01

The greater proportion of oxygen in the blood circulating in veins of the lower limbs bought to attention the possibility of pre-capillary arteriovenous shunting. The intra-arteriel injection of Technetium labelled serum albumin microspheres enables one to quantify arteriovenous shunts greater than 25 microns. The authors made a comparative study of arterio-venous shunting by blood gases analysis and isotopic techniques in twenty patients. The results seem to deny the existence of arteriovenous shunts in the genesis of essential varicose veins in the lower limb.

Imaging findings of arteriovenous malformations involving lung and liver in hereditary hemorrhagic telangiectasia(Osler-weber-rendu disease): two cases report

Energy Technology Data Exchange (ETDEWEB)

Yi, Jeong Geun; Lee, Joo Hyuk; Seong, Su Ok [Cheongju St. Mary' s Hospital, Cheongju (Korea, Republic of)

1999-09-01

Hereditary hemorrhagic telangiectasia (HHT) or Osler-Weber-Rendu disease is an autosomal dominant disorder characterized by repeated episodes of bleeding. Multiple telangiectases consisting of thin-walled, dilated vascular channels with arteriovenous communication may involve, for example, mucocutaneous tissue, the gastrointestinal tract, and the liver, lung, and brain. We report the imaging findings of two cases of HHT involving arteriovenous malformation of both the lungs and liver, a rare condition. Chest radiography revealed a round mass, while helical CT showed a feeding artery and draining vein with arteriovenous malformation in the lung. Color Doppler sonography revealed an enlarged and tortuous hepatic artery with high systolic velocity. CT demonstrated an enlarged hepatic artery, arteriovenous shunt, and early draining hepatic vein in the liver. Celiac angiography showed arteriovenous malformation.

Imaging findings of arteriovenous malformations involving lung and liver in hereditary hemorrhagic telangiectasia(Osler-weber-rendu disease): two cases report

International Nuclear Information System (INIS)

Yi, Jeong Geun; Lee, Joo Hyuk; Seong, Su Ok

1999-01-01

Hereditary hemorrhagic telangiectasia (HHT) or Osler-Weber-Rendu disease is an autosomal dominant disorder characterized by repeated episodes of bleeding. Multiple telangiectases consisting of thin-walled, dilated vascular channels with arteriovenous communication may involve, for example, mucocutaneous tissue, the gastrointestinal tract, and the liver, lung, and brain. We report the imaging findings of two cases of HHT involving arteriovenous malformation of both the lungs and liver, a rare condition. Chest radiography revealed a round mass, while helical CT showed a feeding artery and draining vein with arteriovenous malformation in the lung. Color Doppler sonography revealed an enlarged and tortuous hepatic artery with high systolic velocity. CT demonstrated an enlarged hepatic artery, arteriovenous shunt, and early draining hepatic vein in the liver. Celiac angiography showed arteriovenous malformation

Intrastriatal Grafting of Chromospheres: Survival and Functional Effects in the 6-OHDA Rat Model of Parkinson's Disease.

Directory of Open Access Journals (Sweden)

Alejandra Boronat-García

Full Text Available Cell replacement therapy in Parkinson's disease (PD aims at re-establishing dopamine neurotransmission in the striatum by grafting dopamine-releasing cells. Chromaffin cell (CC grafts produce some transitory improvements of functional motor deficits in PD animal models, and have the advantage of allowing autologous transplantation. However, CC grafts have exhibited low survival, poor functional effects and dopamine release compared to other cell types. Recently, chromaffin progenitor-like cells were isolated from bovine and human adult adrenal medulla. Under low-attachment conditions, these cells aggregate and grow as spheres, named chromospheres. Here, we found that bovine-derived chromosphere-cell cultures exhibit a greater fraction of cells with a dopaminergic phenotype and higher dopamine release than CC. Chromospheres grafted in a rat model of PD survived in 57% of the total grafted animals. Behavioral tests showed that surviving chromosphere cells induce a reduction in motor alterations for at least 3 months after grafting. Finally, we found that compared with CC, chromosphere grafts survive more and produce more robust and consistent motor improvements. However, further experiments would be necessary to determine whether the functional benefits induced by chromosphere grafts can be improved, and also to elucidate the mechanisms underlying the functional effects of the grafts.

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.

Cerebral arteriovenous malformation in Noonan's syndrome.

OpenAIRE

Schon, F.; Bowler, J.; Baraitser, M.

1992-01-01

Noonan's syndrome involves the association of multiple congenital abnormalities including neck webbing, pectus excavatum, facial anomalies with a variety of cardiac defects. In this paper the association of Noonan's syndrome with a large cerebral arteriovenous malformation is reported. Congenital cerebrovascular abnormalities are not a recognized feature of the syndrome. The paper also reviews previous reports of neurological associations with Noonan's syndrome, the commonest being mild intel...

Management of intracranial dural arteriovenous shunts in adults

International Nuclear Information System (INIS)

Sarma, Dipanka; Brugge, Karel ter

2003-01-01

Dural arteriovenous shunts are abnormal arteriovenous communications within the dura. They are thought to be an acquired condition in adults and can present with a variety of clinical features, ranging from benign bruits to intracranial hemorrhage and neurological deficits. The presentation and natural history of these shunts is largely determined by the pattern of venous drainage. Knowledge of natural history and careful study of the angioarchitexture by angiography is therefore mandatory for correct management of these lesions. In this review, principles of management in adults and the various factors that influence treatment decisions are discussed, with a focus on endovascular therapy. Retrograde leptomeningeal or cortical venous drainage has a strong correlation with adverse clinical events and the requirement for aggressive management in this situation is highlighted. Indications for endovascular treatment, therapeutic goals, approaches and techniques are reviewed. The role of surgical treatment is also briefly discussed

Graft irradiation abrogates graft-versus-host disease in combined pancreas-spleen transplantation

International Nuclear Information System (INIS)

Schulak, J.A.; Sharp, W.J.

1986-01-01

A model of combined pancreas-spleen transplantation (PST) was studied in LBN F1 recipients of Lewis grafts in order to evaluate the efficacy of pretransplant graft irradiation in preventing lethal graft-versus-host disease (GVHD). Recipients of unmodified PST uniformly developed severe GVHD and died (MST = 16.7 +/- 3.8 days). Whole body donor irradiation with either 500 or 250 rad prevented lethal GVHD. Similarly, ex vivo graft irradiation with either 1000 or 500 rad also resulted in normal weight gain, graft function, and host survival for the 6-week study period. Conversely, delay of graft irradiation until 3 days after transplantation failed to prevent this complication (MST = 15.8 +/- 3.7 days). Recipients of irradiated grafts displayed glucose tolerance tests that were identical to those in the control group indicating that the doses of radiation employed in these experiments were not deleterious to islet function. Irradiated spleen grafts appeared histologically normal at 6 weeks after transplantation. Cells derived from these grafts failed to stimulate lymph node enlargement in a popliteal lymph node assay for GVHD, suggesting that these spleens may have become repopulated with host cells. These experiments confirm that PST has the potential to cause lethal GVHD and suggest that pretransplant graft irradiation may be used to prevent its occurrence

A new method of modelling early plasma creatinine changes predicts 1-year graft function after kidney transplantation

DEFF Research Database (Denmark)

Krogstrup, Nicoline V; Bibby, Bo Martin; Aulbjerg, Camilla

2016-01-01

BACKGROUND: Delayed graft function after renal transplantation is associated with inferior long-term outcome. To evaluate the impact of slow onset graft function, we aimed to model and correlate early changes in plasma creatinine (p-cr) with long-term graft function. MATERIALS: In a single centre...

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.

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.

Pulmonary arteriovenous malformations: overview and transcatheter embolotherapy

International Nuclear Information System (INIS)

Pugash, R.A.

2001-01-01

The majority of pulmonary arteriovenous malformations (pAVMs) are found in people with hereditary hemorrhagic telangiectasia (HHT), a condition also known as Osler-Weber-Rendu syndrome. HHT is a clinically heterogeneous autosomal dominant disorder in which abnormal blood vessels cause bleeding and arteriovenous shunting. The 2 basic lesions of HHT - telangiectasias and arteriovenous malformations (AVMs) - are closely related. Multisystem involvement leads to a staggering array of clinical manifestations, making HHT one of medicine's less familiar 'great pretenders'. Telangiectasias are dilated blood vessels, typically located in mucocutaneous surfaces (i.e., skin, conjunctiva, respiratory tract, gastrointestinal tract, urinary tract). Small telangiectasias are simply dilated post-capillary venules, whereas larger telangiectasias are made up of dilated arterioles and venules, often with no intervening capillary. They are, in essence, diminutive AVMs. These tiny lesions are visible as punctate bright red spots on skin and mucosal surfaces (Fig. 1). Their fragility and superficial location account for the disabling epistaxis and chronic gastrointestinal bleeding, which are so common with HHT. Hematuria (caused by urothelial telangiectasias) occurs occasionally but is not a prominent feature of the disease. Although tracheobronchial telangiectasias do occur and may cause hemoptysis, severe hemoptysis is typically related to pAVM rupture. AVMs are direct artery-to-vein connections. Though larger and far more impressive radiologically than telangiectasias, AVMs are more likely to be clinically silent until they either declare themselves in a catastrophic fashion or are detected by screening tests. In contrast to telangiectasias, which are generally found in epithelial surfaces, AVMs tend to develop within organs, most commonly the lung and brain. As screening methods evolve, liver involvement with both telangiectasias and complex AVMs is being recognized with increasing

Pulmonary arteriovenous malformations: overview and transcatheter embolotherapy

Energy Technology Data Exchange (ETDEWEB)

Pugash, R.A. [Univ. of Toronto, St. Michael' s Hospital, Dept. of Medical Imaging, Toronto, Ontario (Canada)

2001-04-01

The majority of pulmonary arteriovenous malformations (pAVMs) are found in people with hereditary hemorrhagic telangiectasia (HHT), a condition also known as Osler-Weber-Rendu syndrome. HHT is a clinically heterogeneous autosomal dominant disorder in which abnormal blood vessels cause bleeding and arteriovenous shunting. The 2 basic lesions of HHT - telangiectasias and arteriovenous malformations (AVMs) - are closely related. Multisystem involvement leads to a staggering array of clinical manifestations, making HHT one of medicine's less familiar 'great pretenders'. Telangiectasias are dilated blood vessels, typically located in mucocutaneous surfaces (i.e., skin, conjunctiva, respiratory tract, gastrointestinal tract, urinary tract). Small telangiectasias are simply dilated post-capillary venules, whereas larger telangiectasias are made up of dilated arterioles and venules, often with no intervening capillary. They are, in essence, diminutive AVMs. These tiny lesions are visible as punctate bright red spots on skin and mucosal surfaces (Fig. 1). Their fragility and superficial location account for the disabling epistaxis and chronic gastrointestinal bleeding, which are so common with HHT. Hematuria (caused by urothelial telangiectasias) occurs occasionally but is not a prominent feature of the disease. Although tracheobronchial telangiectasias do occur and may cause hemoptysis, severe hemoptysis is typically related to pAVM rupture. AVMs are direct artery-to-vein connections. Though larger and far more impressive radiologically than telangiectasias, AVMs are more likely to be clinically silent until they either declare themselves in a catastrophic fashion or are detected by screening tests. In contrast to telangiectasias, which are generally found in epithelial surfaces, AVMs tend to develop within organs, most commonly the lung and brain. As screening methods evolve, liver involvement with both telangiectasias and complex AVMs is being recognized

Cyst formation after radiosurgery for brain arteriovenous malformation treated with cystoperitoneal shunt

International Nuclear Information System (INIS)

Morihiro, Yusuke; Kato, Syoichi; Imoto, Hirochika

2010-01-01

Gamma knife and CyberKnife radiosurgery are well established and less invasive treatments for arteriovenous malformation. Delayed cyst formation is a rare but well-known complication of radiosurgery for arteriovenous malformations. The optimal treatment of cysts forming after radiosurgery remains debatable. We present a case of cyst formation after radiosurgery for brain arteriovenous malformation that was treated with a cystoperitoneal shunt (C-P shunt). A 36-year-old woman presented with left hemiparesis and numbness. Computed tomography (CT) revealed intracranial hemorrhage in the right basal ganglia. Digital subtraction angiography revealed arteriovenous malformation in the brain. Intravascular embolization was performed three times and radiosurgery was performed twice, whereby complete obliteration of the nidus was achieved. Six and a half years later, routine follow-up magnetic resonance imaging revealed cyst formation, and the patient gradually developed left hemiparesis. First, we performed stereotactic cyst aspiration. This initially resulted in a reduction in the size of the cyst and disappearance of left hemiparesis, but within a short time, the cyst increased in size again and there was recurrence of hemiparesis. Therefore, an Ommaya reservoir was established; aspiration of the cyst through this reservoir brought about an initial reduction in cyst size and alleviation of symptoms; however, no further reduction in cyst size or improvement in symptoms could be achieved. Twenty months after the placement of the Ommaya reservoir, we performed a C-P shunt operation. After the operation, further reduction in the cyst size and complete symptomatic recovery were observed. (author)

Eph-B4 regulates adaptive venous remodeling to improve arteriovenous fistula patency

OpenAIRE

Protack, Clinton D.; Foster, Trenton R.; Hashimoto, Takuya; Yamamoto, Kota; Lee, Monica Y.; Kraehling, Jan R.; Bai, Hualong; Hu, Haidi; Isaji, Toshihiko; Santana, Jeans M.; Wang, Mo; Sessa, William C.; Dardik, Alan

2017-01-01

Low rates of arteriovenous fistula (AVF) maturation prevent optimal fistula use for hemodialysis; however, the mechanism of venous remodeling in the fistula environment is not well understood. We hypothesized that the embryonic venous determinant Eph-B4 mediates AVF maturation. In human AVF and a mouse aortocaval fistula model, Eph-B4 protein expression increased in the fistula vein; expression of the arterial determinant Ephrin-B2 also increased. Stimulation of Eph-B-mediated signaling with ...

Patients on hemodialysis are better served by a proximal arteriovenous fistula for long-term venous access.

LENUS (Irish Health Repository)

Sultan, Sherif

2012-11-01

Patients with end-stage renal disease should have arteriovenous fistula (AVF) formation 3 to 6 months prior to commencing hemodialysis (HD). However, this is not always possible with strained health care resources. We aim to compare autologous proximal AVF (PAVF) with distal AVF (DAVF) in patients already on HD. Primary end point is 4-year functional primary. Secondary end point is freedom from major adverse clinical events (MACEs). From January 2003 to June 2009, out of 495 AVF formations, 179 (36%) patients were already on HD. These patients had 200 AVF formations (49 DAVF vs 151 PAVF) in arms in which no previous fistula had been formed. No synthetic graft was used. Four-year primary functional patency significantly improved with PAVF (68.9% ± SD 8.8%) compared to DAVF (7.3% ± SD 4.9%; P < .0001). Five-year freedom from MACE was 85% with PAVF compared to 40% with DAVF (P < .005). Proximal AVF bestows long-term functional access with fewer complications compared to DAVF for patients already on HD.

UTERINE ARTERIOVENOUS MALFORMATION: A CASE REPORT

OpenAIRE

Chandrashekar Murthy; Kiran

2014-01-01

Uterine arteriovenous malformation (AVM) is a rare condition, with less than 100 cases reported in the literature. Despite it being rare, it is a potentially life threatening disease. This case report describes 31- year-old women who presented with abnormal uterine bleeding. Trans abdominal sonography, colour and spectral Doppler imaging was performed, diagnosis was confirmed by non- invasive MRI scan. Laparoscopic bilateral uterine artery ligation was done successfully.

[Extracorporeal membrane oxygenation in primary graft dysfunction in a paediatric double lung transplant: presentation of a case].

Science.gov (United States)

López-Cantero, M; Grisolía, A L; Vicente, R; Moreno, I; Ramos, F; Porta, J; Torregrosa, S

2014-04-01

Primary graft dysfunction is a leading cause of morbimortality in the immediate postoperative period of patients undergoing lung transplantation. Among the treatment options are: lung protective ventilatory strategies, nitric oxide, lung surfactant therapy, and supportive treatment with extracorporeal membrane oxygenation (ECMO) as a bridge to recovery of lung function or re-transplant. We report the case of a 9-year-old girl affected by cystic fibrosis who underwent double-lung transplantation complicated with a severe primary graft dysfunction in the immediate postoperative period and refractory to standard therapies. Due to development of multiple organ failure, it was decided to insert arteriovenous ECMO catheters (pulmonary artery-right atrium). The postoperative course was satisfactory, allowing withdrawal of ECMO on the 5th post-surgical day. Currently the patient survives free of rejection and with an excellent quality of life after 600 days of follow up. Copyright © 2012 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

Percutaneous endovascular stent-graft treatment of aortic aneurysms and dissections: new techniques and initial experience

Energy Technology Data Exchange (ETDEWEB)

Lee, Do Yun; Choi, Dong Hoon; Kang, Sung Gwon; Lee, Kwang Hoon; Won, Jong Yun [Yonsei University College of Medicine, Seoul (Korea, Republic of); Kang, Sung Gwon [Chosun University College of Medicine, Gwangju (Korea, Republic of); Won, Je Whan [Aju University College of Medicine, Suwon (Korea, Republic of); Song, Ho Young [Ulsan University College of Medicine, Seoul (Korea, Republic of)

2003-01-01

To evaluate the feasibility, safety and effectiveness of a newly designed percutaneously implanted separate stent-graft (SSG) for the treatment of aortic aneurysms and dissections. Using a percutaneous technique, SSG placement (in the descending thoracic aorta in 26 cases and infrarenal abdominal aorta in 24) was attempted in 50 patients with aortic aneurysms (n=27) or dissection (n=23). All SSGs were individually constructed using self-expandable nitinol stents and a Dacron graft, and were introduced through a 12 F sheath and expanded to a diameter of 20-34 mm. In all cases, vascular access was through the femoral artery. The clinical status of each patient was monitored, and postoperative CT was performed within one week of the procedure and at 3-6 month intervals afterwards. Endovascular stent-graft deployment was technically successful in 49 of 50 patients (98%). The one failure was due to torsion of the unsupported graft during deployment. Successful exclusion of aneurysms and the primary entry tears of dissections was achieved in all but three patients with aortic dissection. All patients in whom technical success was achieved showed complete thrombosis of the thoracic false lumen or aneurysmal sac, and the overall technique success rate was 92%. In addition, sixteen patients demonstrated complete resolution of the dissected thoracic false lumen (n=9) or aneurysmal sac (n=7). Immediate post-operative complications occurred at the femoral puncture site in one patient with an arteriovenous fistula, and in two, a new saccular aneurysm developed at the distal margin of the stent. No patients died, and there was no instance of paraplegia, stroke, side-branch occlusion or infection during the subsequent mean follow-up period of 9.4 (range, 2 to 26) months. In patients with aortic aneurysm and dissection, treatment with a separate percutaneously inserted stent-graft is technically feasible, safe, and effective.

Analysis of 855 upper extremity fistulas created using a standard protocol: the role of graft extension to achieve functional status.

Science.gov (United States)

Allan, Bassan J; Perez, Enrique R; Tabbara, Marwan

2013-06-01

The Fistula First Breakthrough Initiative (FFBI) has been one of the most important national programs to help achieve considerable improvements in the care of patients on chronic hemodialysis. FFBI has helped place guidelines to push practitioners to reduce the use of tunneled central venous catheters and to increase the rate of arteriovenous fistula use in patients requiring chronic hemodialysis access. However, despite current guidelines, no specific protocols exist for the creation and management of autogenous arteriovenous fistulas and outcomes at most centers are below national benchmarks. In this study, we examine the effectiveness of a standard protocol used at our institution for the creation of autogenous upper extremity fistulas for hemodialysis access in achieving early cannulation and early removal of tunneled dialysis catheters. Our review encompasses 855 consecutive autogenous fistulas created over a 10-year period. Our findings suggest that the use of a standard protocol for creation and management of autogenous fistulas can help increase the rate of functional accesses over national benchmarks. Additionally, extension/conversion of malfunctioning fistulas to grafts appears to be an excellent method to expedite removal of a tunneled dialysis catheter with concomitant preservation of a fistula.

Non-Imaging Acoustical Properties in Monitoring Arteriovenous Hemodialysis Access. A Review

Directory of Open Access Journals (Sweden)

Anas Mohd Noor

2015-12-01

Full Text Available The limitations of the gold standard angiography technique in arteriovenous access surveillance have opened a gap for researchers to find the best way to monitor this condition with low-cost, non-invasive and continuous bedside monitoring. The phonoangiography technique has been developed prior to these limits. This measurement and monitoring technique, associated with intelligence signal processing, promises better analysis for early detection of hemodialysis access problems, such as stenosis and thrombosis. Some research groups have shown that the phonoangiography technique could identify as many as 20% of vascular diameter changes and also its frequency characteristics due to hemodialysis access problems. The frequency characteristics of these acoustical signals are presented and discussed in detail to understand the association with the stenosis level, blood flows, sensor locations, fundamental frequency bands of normal and abnormal conditions, and also the spectral energy produced. This promising technique could be used in the near future as a tool for pre-diagnosis of arteriovenous access before any further access correction by surgical techniques is required. This paper provides an extensive review of various arteriovenous access monitoring techniques based on non-imaging acoustical properties.

Adding a PECS II block for proximal arm arteriovenous access - a randomised study.

Science.gov (United States)

Quek, K H; Low, E Y; Tan, Y R; Ong, A S C; Tang, T Y; Kam, J W; Kiew, A S C

2018-05-01

Brachial plexus block is often utilised for proximal arm arteriovenous access creation. However, the medial upper arm and axilla are often inadequately anaesthetised, requiring repeated, intraoperative local anaesthetic supplementation, or conversion into general anaesthesia. We hypothesised that the addition of a PECS II block would improve anaesthesia and analgesia for proximal arm arteriovenous access surgery. In this prospective, double-blinded, randomised proof-of-concept study, 36 consenting adults with end-stage renal disease aged between 21 and 90 years received either a combined supraclavicular and PECS II block (Group PECS, n = 18), or combined supraclavicular and sham block (Group SCB, n = 18) for proximal arm arteriovenous access surgery. Primary outcome was whether patients required intraoperative local anaesthetic supplementation by the surgeon. In Group PECS, 33.3% (6/18) needed local anaesthetic supplementation vs. 100% (18/18) in Group SCB. Group SCB had three times (RR 3.0, 95% CI 1.6-5.8; P PECS required lower volume of supplemental local anaesthetic compared to Group SCB (0.0 ml, IQR 0.0-6.3 ml vs. 15.0 ml, IQR 7.4-17.8 ml; P PECS II block to a supraclavicular block improves regional anaesthesia for patients with end-stage renal disease undergoing proximal arm arteriovenous access surgery. © 2018 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Assessment of Arteriovenous Shunt Pathway Function and Hypervolemia for Hemodialysis Patients by Using Integrated Rapid Screening System

Directory of Open Access Journals (Sweden)

Wei-Ling Chen

2017-06-01

Full Text Available Currently, the hemodialysis patients received body weight measurement by themselves, vital sign checking by nursing staffs before dialysis. Whenever, the arteriovenous routes with problems doubted, the patients needed to be referred to surgeon for vascular echography checking and then to be corrected. How to integrate these three tasks in one time is a very important issue. The project proposes to combine our previous study of audio-phono angiographic technology in detecting vascular stenosis with rapid screening system to evaluate dialysis patients’ arteriovenous routes function and their status of excess body fluids: inspecting and integrating the blood pressure, body weight, and fistula function work into a rapid screening system, and using the quantization of fistula phono angiography pitch to achieve assessing arteriovenous routes. Future hoping is developed a complete integrated intelligence system by combining the arteriovenous fistula signal processing with feature extraction with wireless sensor network technology.

Epidural haematoma: pathophysiological significance of extravasation and arteriovenous shunting

International Nuclear Information System (INIS)

Habash, A.H.; Sortland, O.; Zwetnow, N.N.

1982-01-01

35 patients with epidural bleeding operated on at Rikshospitalet, Oslo, during the period 1965 - 1980 had preoperative angiography with visualization of the external carotid artery. Twenty-one patients had extravasation of contrast medium from meningeal arteries. Seventeen of the 21 had also shunting of contrast medium from meningeal arteries to meningeal or diploic veins, while 20 of the 21 also had bled from a ruptured meningeal artery at operation. It was further found that of 20 patients who deteriorated after trauma 18 had an epidural arteriovenous shunt or extravasation. Conversely, of 15 patients who improved after trauma 12 had no evidence of a shunt. The strong correlation between the clinical course and the occurrence of extravasation supports previous experimental and clinical data, indicating the epidural arteriovenous shunt to be a major factor in the pathophysiology and the outcome of epidural bleeding. (author)

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

Congenital pulmonary arteriovenous malformation: a rare cause of ...

African Journals Online (AJOL)

Pulmonary arteriovenous malformation (PAVM) is a rare condition in which there is abnormal connection between pulmonary arteries and veins. The disorder usually appears in late childhood or early adult life, with dyspnea on exertion, clubbing or cyanosis. We present two patients with severe cyanosis and their work-up ...

Embolization of spinal arteriovenous malformations

International Nuclear Information System (INIS)

Son, Mi Young; Kim, Sun Yong; Park, Bok Hwan

1990-01-01

Recently, therapeutic embolization has been advocated as the treatment of choice for spinal AVM(arteriovenous malformations). The authors review our experience with two cases of spinal AVM treated by embolization using coaxial Tracker-18 microcatheter with Latvian. The patients included a 10 year old male with glomus type and a 14 year old female with juvenile type spinal AVM revealed recanalization 5 month later. Embolization provides curative or temporary treatment for spinal AVM. After embolic occlusion, delayed reassessment with arteriography is indicated, particularly if symptoms persist or recur

A new beating-heart off-pump coronary artery bypass grafting training model

NARCIS (Netherlands)

Bouma, Wobbe; Kuijpers, Michiel; Bijleveld, Aanke; De Maat, Gijs E.; Koene, Bart M.; Erasmus, Michiel E.; Natour, Ehsan; Mariani, Massimo A.

OBJECTIVES: Training models are essential in mastering the skills required for off-pump coronary artery bypass grafting (OPCAB). We describe a new, high-fidelity, effective and reproducible beating-heart OPCAB training model in human cadavers. METHODS: Human cadavers were embalmed according to the

A case report of spinal dural arteriovenous fistula: origins, determinants, and consequences of abnormal vascular malformations.

Science.gov (United States)

Zakhary, Sherry M; Hoehmann, Christopher L; Cuoco, Joshua A; Hitscherich, Kyle; Alam, Hamid; Torres, German

2017-06-01

A spinal dural arteriovenous fistula is an abnormally layered connection between radicular arteries and venous plexus of the spinal cord. This vascular condition is relatively rare with an incidence of 5-10 cases per million in the general population. Diagnosis of spinal dural arteriovenous fistula is differentiated by contrast-enhanced magnetic resonance angiography or structural magnetic resonance imaging, but a definitive diagnosis requires spinal angiography methods. Here, we report a case of a 67-year-old female with a spinal dural arteriovenous fistula, provide a pertinent clinical history to the case nosology, and discuss the biology of adhesive proteins, chemotactic molecules, and transcription factors that modify the behavior of the vasculature to possibly cause sensorimotor deficits.

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.

Endovascular Revascularization of Hemodialysis Thrombosed Grafts with the Hydrodynamic Thrombectomy Catheter. Our 7-Year Experience

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Bermudez, Patrícia, E-mail: pbermude@clinic.ub.es [Clinic Hospital of Barcelona, Vascular and Interventional Radiology Unit, Diagnostic Imaging Institute (Spain); Fontseré, Nestor, E-mail: fontsere@clinic.ub.es [Clinic Hospital of Barcelona, Vascular Access Unit, Nephrologic and Urologic Diseases Clinical Institute (Spain); Mestres, Gaspar, E-mail: gmestres@clinic.ub.es [Clinic Hospital of Barcelona, Cardiovascular Diseases Institute (Spain); García-Gámez, Andres, E-mail: garciagam@clinic.ub.es; Barrufet, Marta, E-mail: barrufet@clinic.ub.es; Burrel, Marta, E-mail: mburrel@clinic.ub.es; Gilabert, Rosa, E-mail: gilabert@clinic.ub.es; Gómez, Fernando, E-mail: fegomez@clinic.ub.es; Macho, Juan, E-mail: jmmacho@clinic.ub.es [Clinic Hospital of Barcelona, Vascular and Interventional Radiology Unit, Diagnostic Imaging Institute (Spain)

2017-02-15

PurposeTo evaluate the efficacy and safety of the hydrodynamic thrombectomy catheter (AngioJet DVX) in the salvage of thrombosed hemodialysis vascular grafts.Materials and MethodsA retrospective study was designed, including all patients with occluded arteriovenous grafts treated with the AngioJet system between 2007 and 2014 in our institution. Outcomes included technical success, clinical success, complications, and primary and secondary patencies. Procedural success was defined as angiographic confirmation of flow restoration, the presence of a pulsatile thrill along the graft, and successful resumption of at least one hemodialysis session. Primary and secondary patencies after first AVG thrombectomy were calculated with Kaplan–Meier curves. Cox regression was used to determine prognostic factors of primary patency after every thrombectomy episode.ResultsA total of 149 thrombectomies were performed in 68 grafts. After thrombectomy, endovascular treatment of one or more stenosis was performed in all cases. Technical success was 93% and clinical success was 86%. Complications occurred in 7 thrombectomies, most of them were minor except for one anastomosis rupture requiring surgery. Primary and secondary patencies were 52, 41, and 23 and 76, 68, and 57% at 3, 6 and 12 months, respectively. Independent prognostic factors of poor patency after every thrombectomy episode were the presence of residual thrombus (OR 1.831, P = 0.008) and time from last thrombosis (less than 1 month; and OR 7.116, P < 0.001).ConclusionPercutaneous mechanical thrombectomy with AngioJet is a safe technique with a high-clinical success rate. The presence of residual thrombus after thrombectomy and early re-occlusions are related to poorer results.

Perkutan transluminal embolisering af pulmonale arteriovenøse misdannelser

DEFF Research Database (Denmark)

Kjeldsen, A D; Andersen, P E; Oxhøj, H

1998-01-01

A series of nine patients with pulmonary arteriovenous malformations (PAVM) treated with embolotherapy at Odense University Hospital is presented. In all patients the arterial oxygen tension increased after embolisation. PAVM causes right-to-left shunting, which may result in severe hypoxaemia, and...

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,

Linear accelerator radiosurgery for arteriovenous malformations: Updated literature review.

Science.gov (United States)

Yahya, S; Heyes, G; Nightingale, P; Lamin, S; Chavda, S; Geh, I; Spooner, D; Cruickshank, G; Sanghera, P

2017-04-01

Arteriovenous malformations (AVMs) are the leading causing of intra-cerebral haemorrhage. Stereotactic radiosurgery (SRS) is an established treatment for arteriovenous malformations (AVM) and commonly delivered using Gamma Knife within dedicated radiosurgery units. Linear accelerator (LINAC) SRS is increasingly available however debate remains over whether it offers an equivalent outcome. The aim of this project is to evaluate the outcomes using LINAC SRS for AVMs used within a UK neurosciences unit and review the literature to aid decision making across various SRS platforms. Results have shown comparability across platforms and strongly supports that an adapted LINAC based SRS facility within a dynamic regional neuro-oncology department delivers similar outcomes (in terms of obliteration and toxicity) to any other dedicated radio-surgical platform. Locally available facilities can facilitate discussion between options however throughput will inevitably be lower than centrally based dedicated national radiosurgery units. Copyright © 2016. Published by Elsevier Ltd.

Acquired arteriovenous fistula in a grizzly bear (Ursus arctos horribilis).

Science.gov (United States)

Tuttle, Allison D; MacLean, Robert A; Linder, Keith; Cullen, John M; Wolfe, Barbara A; Loomis, Michael

2009-03-01

A captive adult male grizzly bear (Ursus arctos horribilis) was evaluated due to multifocal wounds of the skin and subcutaneous tissues sustained as a result of trauma from another grizzly bear. On presentation, one lesion that was located in the perineal region seemed to be a deep puncture with purple tissue protruding from it. This perineal wound did not heal in the same manner or rate as did the other wounds. Twenty-five days after initial detection, substantial active hemorrhage from the lesion occurred and necessitated anesthesia for examination of the bear. The entire lesion was surgically excised, which later proved curative. An acquired arteriovenous fistula was diagnosed via histopathology. Arteriovenous fistulas can develop after traumatic injury and should be considered as a potential complication in bears with nonhealing wounds.

Technique to Avoid Hemodialysis Catheter in Patients with Failing Aneurysmal Arteriovenous Fistula by Creating a Concomitant New Arteriovenous Fistula.

Science.gov (United States)

Lara, Kelly A; Chua, Rochelle Anne; Vo, Trung D

2018-05-01

Autogenous arteriovenous fistula (AVF) is the primary recommended access for hemodialysis. Long-term use will not uncommonly result in AVF aneurysmal degeneration. Aneurysm-associated complications encompass pain, skin ulceration, infection, thrombosis, cannulation difficulties, and life-threatening bleeding. Various methods to repair aneurysmal AVFs have been described. However, there may be circumstances when this is not possible and require insertion of a temporary hemodialysis catheter (HDC) until a new arteriovenous access is created. We describe a case series of creating a new simultaneous AVF while continuing to use the primary failing aneurysmal AVF to avoid placement of an HDC. Once the new AVF becomes operational, the primary aneurysmal AVF can be abandoned. Six patients underwent simultaneous new AVF creation, 4 ipsilateral, and 2 contralateral. None of the patients developed symptomatic steal syndrome or congestive heart failure. Five of 6 patients had successful usage of the new AVF, and subsequently underwent ligation and excision of the aneurysmal AVF, thus avoiding a temporary HDC. Close monitoring for skin compromise and bleeding in the aneurysmal AVF is recommended while the new AVF matures. Copyright © 2018 Elsevier Inc. All rights reserved.

Novel brain arteriovenous malformation mouse models for type 1 hereditary hemorrhagic telangiectasia.

Directory of Open Access Journals (Sweden)

Eun-Jung Choi

Full Text Available Endoglin (ENG is a causative gene of type 1 hereditary hemorrhagic telangiectasia (HHT1. HHT1 patients have a higher prevalence of brain arteriovenous malformation (AVM than the general population and patients with other HHT subtypes. The pathogenesis of brain AVM in HHT1 patients is currently unknown and no specific medical therapy is available to treat patients. Proper animal models are crucial for identifying the underlying mechanisms for brain AVM development and for testing new therapies. However, creating HHT1 brain AVM models has been quite challenging because of difficulties related to deleting Eng-floxed sequence in Eng(2fl/2fl mice. To create an HHT1 brain AVM mouse model, we used several Cre transgenic mouse lines to delete Eng in different cell-types in Eng(2fl/2fl mice: R26CreER (all cell types after tamoxifen treatment, SM22α-Cre (smooth muscle and endothelial cell and LysM-Cre (lysozyme M-positive macrophage. An adeno-associated viral vector expressing vascular endothelial growth factor (AAV-VEGF was injected into the brain to induce focal angiogenesis. We found that SM22α-Cre-mediated Eng deletion in the embryo caused AVMs in the postnatal brain, spinal cord, and intestines. Induction of Eng deletion in adult mice using R26CreER plus local VEGF stimulation induced the brain AVM phenotype. In both models, Eng-null endothelial cells were detected in the brain AVM lesions, and formed mosaicism with wildtype endothelial cells. However, LysM-Cre-mediated Eng deletion in the embryo did not cause AVM in the postnatal brain even after VEGF stimulation. In this study, we report two novel HHT1 brain AVM models that mimic many phenotypes of human brain AVM and can thus be used for studying brain AVM pathogenesis and testing new therapies. Further, our data indicate that macrophage Eng deletion is insufficient and that endothelial Eng homozygous deletion is required for HHT1 brain AVM development.

Arteriovenous Malformation in Temporal Lobe Presenting as Contralateral Ocular Symptoms Mimicking Carotid-Cavernous Fistula

Directory of Open Access Journals (Sweden)

Fadzillah Mohd-Tahir

2013-01-01

Full Text Available Aim. To report a rare case of arteriovenous malformation in temporal lobe presenting as contralateral orbital symptoms mimicking carotid-cavernous fistula. Method. Interventional case report. Results. A 31-year-old Malay gentleman presented with 2-month history of painful progressive exophthalmos of his left eye associated with recurrent headache, diplopia, and reduced vision. Ocular examination revealed congestive nonpulsating 7 mm exophthalmos of the left eye with no restriction of movements in all direction. There was diplopia in left lateral gaze. Left IOP was elevated at 29 mmHg. Left eye retinal vessels were slightly dilated and tortuous. CT scan was performed and showed right temporal arteriovenous malformation with a nidus of 3.8 cm × 2.5 cm with right middle cerebral artery as feeding artery. There was dilated left superior ophthalmic vein of 0.9 mm in diameter with enlarged left cavernous sinus. MRA and carotid angiogram confirmed right temporal arteriovenous malformation with no carotid-cavernous fistula. Most of the intracranial drainage was via left cavernous sinus. His signs and symptoms dramatically improved following successful embolisation, completely resolved after one year. Conclusion. Intracranial arteriovenous malformation is rarely presented with primary ocular presentation. Early intervention would salvage the eyes and prevent patients from more disaster morbidity or fatality commonly due to intracranial haemorrhage.

Derivation of a Predictive Model for Graft Loss Following Acute Kidney Injury in Kidney Transplant Recipients.

Science.gov (United States)

Molnar, Amber O; van Walraven, Carl; Fergusson, Dean; Garg, Amit X; Knoll, Greg

2017-01-01

Acute kidney injury (AKI) is common in the kidney transplant population. To derive a multivariable survival model that predicts time to graft loss following AKI. Retrospective cohort study using health care administrative and laboratory databases. Southwestern Ontario (1999-2013) and Ottawa, Ontario, Canada (1996-2013). We included first-time kidney only transplant recipients who had a hospitalization with AKI 6 months or greater following transplant. AKI was defined using the Acute Kidney Injury Network criteria (stage 1 or greater). The first episode of AKI was included in the analysis. Graft loss was defined by return to dialysis or repeat kidney transplant. We performed a competing risk survival regression analysis using the Fine and Gray method and modified the model into a simple point system. Graft loss with death as a competing event was the primary outcome of interest. A total of 315 kidney transplant recipients who had a hospitalization with AKI 6 months or greater following transplant were included. The median (interquartile range) follow-up time was 6.7 (3.3-10.3) years. Graft loss occurred in 27.6% of the cohort. The final model included 6 variables associated with an increased risk of graft loss: younger age, increased severity of AKI, failure to recover from AKI, lower baseline estimated glomerular filtration rate, increased time from kidney transplant to AKI admission, and receipt of a kidney from a deceased donor. The risk score had a concordance probability of 0.75 (95% confidence interval [CI], 0.69-0.82). The predicted 5-year risk of graft loss fell within the 95% CI of the observed risk more than 95% of the time. The CIs of the estimates were wide, and model overfitting is possible due to the limited sample size; the risk score requires validation to determine its clinical utility. Our prognostic risk score uses commonly available information to predict the risk of graft loss in kidney transplant patients hospitalized with AKI. If validated

A case report of spinal dural arteriovenous fistula: origins, determinants, and consequences of abnormal vascular malformations

Directory of Open Access Journals (Sweden)

Sherry M. Zakhary, DO

2017-06-01

Full Text Available A spinal dural arteriovenous fistula is an abnormally layered connection between radicular arteries and venous plexus of the spinal cord. This vascular condition is relatively rare with an incidence of 5–10 cases per million in the general population. Diagnosis of spinal dural arteriovenous fistula is differentiated by contrast-enhanced magnetic resonance angiography or structural magnetic resonance imaging, but a definitive diagnosis requires spinal angiography methods. Here, we report a case of a 67-year-old female with a spinal dural arteriovenous fistula, provide a pertinent clinical history to the case nosology, and discuss the biology of adhesive proteins, chemotactic molecules, and transcription factors that modify the behavior of the vasculature to possibly cause sensorimotor deficits.

Functional recovery after facial nerve cable grafting in a rodent model.

NARCIS (Netherlands)

Hohman, M.H.; Kleiss, I.J.; Knox, C.J.; Weinberg, J.S.; Heaton, J.T.; Hadlock, T.A.

2014-01-01

IMPORTANCE: Cable grafting is widely considered to be the preferred alternative to primary repair of the injured facial nerve; however, quantitative comparison of the 2 techniques has not been previously undertaken in a rodent model. OBJECTIVE: To establish functional recovery parameters after

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

Arteriovenous fistulae after renal biopsy: diagnosis and outcomes using Doppler ultrasound assessment.

Science.gov (United States)

Sosa-Barrios, R Haridian; Burguera, Victor; Rodriguez-Mendiola, Nuria; Galeano, Cristina; Elias, Sandra; Ruiz-Roso, Gloria; Jimenez-Alvaro, Sara; Liaño, Fernando; Rivera-Gorrin, Maite

2017-12-20

Percutaneous renal biopsy (PRB) is an important technique providing relevant information to guide diagnosis and treatment in renal disease. As an invasive procedure it has complications. Most studies up to date have analysed complications related to bleeding. We report the largest single-center experience on routine Doppler ultrasound (US) assessment post PRB, showing incidence and natural history of arteriovenous fistulae (AVF) post PRB. We retrospectively analysed 327 consecutive adult PRB performed at Ramon Cajal University Hospital between January 2011 and December 2014. All biopsies were done under real-time US guidance by a trained nephrologist. Routine Doppler mapping and kidney US was done within 24 h post biopsy regardless of symptoms. Comorbidities, full blood count, clotting, bleeding time and blood pressure were recorded at the time of biopsy. Post biopsy protocol included vitals and urine void checked visually for haematuria. Logistic regression was used to investigate links between AVF, needle size, correcting for potential confounding variables. 46,5% were kidney transplants and 53,5% were native biopsies. Diagnostic material was obtained in 90,5% (142 grafts and 154 native). Forty-seven AVF's (14.37%) were identified with routine kidney Doppler mapping, 95% asymptomatic (n = 45), 28 in grafts (18.4%) and 17 natives (9.7%) (p-value 0.7). Both groups were comparable in terms of comorbidities, passes, cylinders or biopsy yield (p-value NS). 80% were <1 cm in size and 46.6% closed spontaneously in less than 30 days (range 3-151). Larger AVF's (1-2 cm) took a mean of 52 days to closure (range 13-151). Needle size was not statistically significant factor for AVF (p-value 0.71). Contrary to historical data published, AVF's are a common complication post PRB that can be easily missed. Routine US Doppler mapping performed by trained staff is a cost-effective, non-invasive tool to diagnose and follow up AVF's, helping to assess management.

Dural arteriovenous fistula as a treatable dementia.

Science.gov (United States)

Enofe, Ikponmwosa; Thacker, Ike; Shamim, Sadat

2017-04-01

Dementia is a chronic loss of neurocognitive function that is progressive and irreversible. Although rare, dural arteriovenous fistulas (DAVFs) could present with a rapid decline in neurocognitive function with or without Parkinson-like symptoms. DAVFs represent a potentially treatable and reversible cause of dementia. Here, we report the case of an elderly woman diagnosed with a DAVF after presenting with new-onset seizures, deteriorating neurocognitive function, and Parkinson-like symptoms.

Impact of bone graft harvesting techniques on bone formation and graft resorption

DEFF Research Database (Denmark)

Saulacic, Nikola; Bosshardt, Dieter D; Jensen, Simon S

2015-01-01

BACKGROUND: Harvesting techniques can affect cellular parameters of autogenous bone grafts in vitro. Whether these differences translate to in vivo bone formation, however, remains unknown. OBJECTIVE: The purpose of this study was to assess the impact of different harvesting techniques on bone fo......: Transplantation of autogenous bone particles harvested with four techniques in the present model resulted in moderate differences in terms of bone formation and graft resorption.......BACKGROUND: Harvesting techniques can affect cellular parameters of autogenous bone grafts in vitro. Whether these differences translate to in vivo bone formation, however, remains unknown. OBJECTIVE: The purpose of this study was to assess the impact of different harvesting techniques on bone...... formation and graft resorption in vivo. MATERIAL AND METHODS: Four harvesting techniques were used: (i) corticocancellous blocks particulated by a bone mill; (ii) bone scraper; (iii) piezosurgery; and (iv) bone slurry collected from a filter device upon drilling. The grafts were placed into bone defects...

Systemic-pulmonary arteriovenous fistula of traumatic origin: A case report

International Nuclear Information System (INIS)

Hirsch, M.; Maroko, I.; Gueron, M.; Goleman, L.

1983-01-01

Arteriovenous fistulas between the systemic circulation and the pulmonary artery are extremely rare. Continuous precordial murmur is the usual clinical sign while unilateral rib notching may be the only radiologic manifestation of this condition. Selective angiographic investigation is necessary to localize the site of such an arteriovenous (AV) fistula before surgery is performed. In a review of the literature of 15 published cases, the majority were of congenital origin, with four of these systemic-pulmonary AV fistulas of traumatic origin, of which one occurred after insertion of an intercostal catheter. We describe one case of traumatic origin 9 years after percutaneous thoracic drainage for spontaneous pneumothorax, in which transcatheter embolic occlusion of the feeding arteries of an AV fistula was attempted. The advantages and the disadvantages of the non-surgical and surgical therapeutic approaches are discussed. (orig.)

Uterine Arteriovenous Fistula with Concomitant Pelvic Varicocele: Endovascular Embolization with Onyx-18®

Directory of Open Access Journals (Sweden)

Francesco Giurazza

2017-01-01

Full Text Available Uterine arteriovenous fistulas are rare and acquired causes of life-threatening vaginal bleeding. They usually present with intermittent menometrorrhagia in young patients in childbearing age with history of gynecological procedures on uterus. Traditional management is hysterectomy; endovascular embolization represents nowadays an alternative strategy for patients wishing to preserve fertility. Here, the endovascular approach to a 29-year-old woman affected by severe menometrorrhagia caused by a uterine arteriovenous fistula with a concomitant pelvic varicocele is reported; a bilateral uterine arteries embolization with Onyx-18 (ev3, Irvine, CA, USA has successfully resolved the fistula with clinical success.

Cranial dural arteriovenous fistula as a rare cause of tinnitus – case report

International Nuclear Information System (INIS)

Kuśmierska, Małgorzata; Gać, Paweł; Nahorecki, Artur; Szuba, Andrzej; JaŸwiec, Przemysław

2013-01-01

Tinnitus, occurring at least once in a lifetime in about 10–20% of the population, is an important clinical problem with complex etiology. Rare causes of tinnitus include cranial dural arteriovenous fistulas (DAVFs), which are usually small lesions consisting of abnormal connections between branches of dural arteries and venous sinuses or veins. Authors present a case of a 44-year-old woman with persistent, unilateral, treatment-resistant pulsatile tinnitus caused by a small dural arteriovenous fistula revealed in computed tomography angiography. Computed tomography angiography is a useful diagnostic method that in some cases allows for establishing the cause of unilateral, pulsatile tinnitus

Cranial dural arteriovenous fistula as a rare cause of tinnitus – case report

Energy Technology Data Exchange (ETDEWEB)

Kuśmierska, Małgorzata; Gać, Paweł [Department of Medical Radiology and Imaging Diagnostics, 4th Military Clinical Hospital, Wrocław (Poland); Nahorecki, Artur [Department of Internal Diseases, 4th Military Clinical Hospital, Wrocław (Poland); Szuba, Andrzej [Department of Internal Diseases, 4th Military Clinical Hospital, Wrocław (Poland); Medical University, Wrocław (Poland); JaŸwiec, Przemysław [Department of Medical Radiology and Imaging Diagnostics, 4th Military Clinical Hospital, Wrocław (Poland)

2013-07-01

Tinnitus, occurring at least once in a lifetime in about 10–20% of the population, is an important clinical problem with complex etiology. Rare causes of tinnitus include cranial dural arteriovenous fistulas (DAVFs), which are usually small lesions consisting of abnormal connections between branches of dural arteries and venous sinuses or veins. Authors present a case of a 44-year-old woman with persistent, unilateral, treatment-resistant pulsatile tinnitus caused by a small dural arteriovenous fistula revealed in computed tomography angiography. Computed tomography angiography is a useful diagnostic method that in some cases allows for establishing the cause of unilateral, pulsatile tinnitus.

Nursing care of indwelling catheter thrombolysis for acute thrombosis in the arteriovenous fistula in hemodialysis patients

International Nuclear Information System (INIS)

Gao Peizhu; Ding Wenbin; Ming Zhibing; Sun Juyun

2010-01-01

Objective: To summarize the experience of the nursing care of indwelling catheter thrombolysis for acute thrombosis in the arteriovenous fistula in eight hemodialysis patients. Methods: After breaking thrombus through indwelling catheter, both bolus injection and micro-pump continuous infusion of urokinase was employed in eight hemodialysis patients with acute thrombosis in the arteriovenous fistula. The necessary nursing measures were carried out to assist the whole therapeutic procedure. Results: All the patients could well cooperate with the procedure of indwelling catheter thrombolysis and urokinase infusion. The reopening rate of the obstructed fistula was 100%. Conclusion: Indwelling catheter thrombolysis with urokinase infusion is a simple, effective and safe treatment for acute thrombosis in the arteriovenous fistula in hemodialysis patients. In order to obtain optimal results, necessary nursing measures must be carried out. (authors)

Animal models of surgically manipulated flow velocities to study shear stress-induced atherosclerosis.

Science.gov (United States)

Winkel, Leah C; Hoogendoorn, Ayla; Xing, Ruoyu; Wentzel, Jolanda J; Van der Heiden, Kim

2015-07-01

Atherosclerosis is a chronic inflammatory disease of the arterial tree that develops at predisposed sites, coinciding with locations that are exposed to low or oscillating shear stress. Manipulating flow velocity, and concomitantly shear stress, has proven adequate to promote endothelial activation and subsequent plaque formation in animals. In this article, we will give an overview of the animal models that have been designed to study the causal relationship between shear stress and atherosclerosis by surgically manipulating blood flow velocity profiles. These surgically manipulated models include arteriovenous fistulas, vascular grafts, arterial ligation, and perivascular devices. We review these models of manipulated blood flow velocity from an engineering and biological perspective, focusing on the shear stress profiles they induce and the vascular pathology that is observed. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Effective flow performances and dialysis doses delivered with permanent catheters: a 24-month comparative study of permanent catheters versus arterio-venous vascular accesses.

Science.gov (United States)

Canaud, Bernard; Leray-Moragues, Hélène; Kerkeni, Nadia; Bosc, Jean-Yves; Martin, Katja

2002-07-01

Permanent venous catheters have emerged as a long-term vascular access option for renal replacement therapy in end-stage renal disease patients. The design and venous location of catheter devices bear intrinsic flow limitations that may negatively affect the adequacy of dialysis and the patient outcome. There is limited data comparing the long-term dialysis adequacy delivered with permanent catheters vs arterio-venous vascular accesses (AVA). To explore this problem, we conducted a prospective 24-month trial comparing the flow performances and dialysis dose (Kt/Vdp) deliveries of both access options in a group of 42 haemodialysis patients during two study phases. During the first 12 months the patients completed a treatment period by means of permanent dual silicone catheters (DualKT). Then they were transferred to an AVA (40 native arterio-venous fistulas and two PTFE grafts) and monitored for an additional 12-month period. Assessments of flow adequacy and dialysis quantification were performed monthly. Dialysis adequacy was achieved in all cases. No patient had to be transferred prematurely to the AVA because of catheter failure. Three catheters had to be replaced due to bacteraemia in three patients. The mean effective blood flow rates achieved were 316+/-3.5 ml/min and 340+/-3.3 ml/min with DualKT and AVA, respectively, for a pre-set machine blood flow of 348+/-2.2 ml/min. Recirculation rates evaluated with the 'slow blood flow' method were 8.6+/-0.6 and 12.1+/-0.8% for DualKT and AVA using mean values of the solute markers urea and creatinine. Due to the possibility of a comparison veno-venous vs arterio-venous blood circulation, a corrected arterio-venous access recirculation could be derived from the difference between the two, which was around 3%. The blood flow resistance of the DualKT was slightly higher than with AVA as indicated by venous pressure differences. Kt/Vdp delivered was 1.37+/-0.02 and 1.45+/-0.02 with DualKT and AVA access respectively. The

Magnetic resonance angiography of arteriovenous malformation in the thalamus

Energy Technology Data Exchange (ETDEWEB)

Oyama, Hirofumi; Kida, Yoshihisa; Kobayashi, Tatsuya; Tanaka, Takayuki; Iwakoshi, Takayasu; Kai, Osamu; Hirose, Mitsuhiko [Komaki City Hospital, Aichi (Japan)

1993-11-01

A comparative study of magnetic resonance angiography and conventional angiography of arteriovenous malformation in the thalamus showed that both methods clearly visualized the feeding arteries: perforating branches of the posterior cerebral artery, posterior choroidal artery and lenticulostriate artery. Draining veins such as the internal cerebral vein were also demonstrated well. (author).

Congenital intrahepatic arterioportal and portosystemic venous fistulae with jejunal arteriovenous malformation depicted on multislice spiral CT

International Nuclear Information System (INIS)

Chae, Eun Jin; Goo, Hyun Woo; Yoon, Chong Hyun; Kim, Seong-Chul

2004-01-01

We report a symptomatic infant with very rare congenital arterioportal and portosystemic venous fistulae in the liver. Multislice CT after partial transcatheter embolisation revealed not only the complicated vascular architecture of the lesion, but also an incidental jejunal arteriovenous malformation which explained the patient's melena. The patient underwent ligation of the hepatic artery and resection of the jejunal arteriovenous malformation. Postoperative multislice CT clearly demonstrated the success of the treatment. (orig.)

Quantifying the Cerebral Hemodynamics of Dural Arteriovenous Fistula in Transverse Sigmoid Sinus Complicated by Sinus Stenosis: A Retrospective Cohort Study.

Science.gov (United States)

Guo, W-Y; Lee, C-C J; Lin, C-J; Yang, H-C; Wu, H-M; Wu, C-C; Chung, W-Y; Liu, K-D

2017-01-01

Sinus stenosis occasionally occurs in dural arteriovenous fistulas. Sinus stenosis impedes venous outflow and aggravates intracranial hypertension by reversing cortical venous drainage. This study aimed to analyze the likelihood of sinus stenosis and its impact on cerebral hemodynamics of various types of dural arteriovenous fistulas. Forty-three cases of dural arteriovenous fistula in the transverse-sigmoid sinus were reviewed and divided into 3 groups: Cognard type I, type IIa, and types with cortical venous drainage. Sinus stenosis and the double peak sign (occurrence of 2 peaks in the time-density curve of the ipsilateral drainage of the internal jugular vein) in dural arteriovenous fistula were evaluated. "TTP" was defined as the time at which a selected angiographic point reached maximum concentration. TTP of the vein of Labbé, TTP of the ipsilateral normal transverse sinus, trans-fistula time, and trans-stenotic time were compared across the 3 groups. Thirty-six percent of type I, 100% of type IIa, and 84% of types with cortical venous drainage had sinus stenosis. All sinus stenosis cases demonstrated loss of the double peak sign that occurs in dural arteriovenous fistula. Trans-fistula time (2.09 seconds) and trans-stenotic time (0.67 seconds) in types with cortical venous drainage were the most prolonged, followed by those in type IIa and type I. TTP of the vein of Labbé was significantly shorter in types with cortical venous drainage. Six patients with types with cortical venous drainage underwent venoplasty and stent placement, and 4 were downgraded to type IIa. Sinus stenosis indicated dysfunction of venous drainage and is more often encountered in dural arteriovenous fistula with more aggressive types. Venoplasty ameliorates cortical venous drainage in dural arteriovenous fistulas and serves as a bridge treatment to stereotactic radiosurgery in most cases. © 2017 by American Journal of Neuroradiology.

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.

Outcomes of Prosthetic Hemodialysis Grafts after Deployment of Bare Metal versus Covered Stents at the Venous Anastomosis

Energy Technology Data Exchange (ETDEWEB)

Kim, Charles Y., E-mail: charles.kim@duke.edu; Tandberg, Daniel J.; Rosenberg, Michael D.; Miller, Michael J.; Suhocki, Paul V.; Smith, Tony P. [Duke University Medical Center, Division of Vascular and Interventional Radiology (United States)

2012-08-15

Purpose: To compare postintervention patency rates after deployment of bare metal versus covered stents across the venous anastomosis of prosthetic arteriovenous (AV) grafts. Methods: Review of our procedural database over a 6 year period revealed 377 procedures involving stent deployment in an AV access circuit. After applying strict inclusion criteria, our study group consisted of 61 stent deployments in 58 patients (median age 58 years, 25 men, 33 women) across the venous anastomosis of an upper extremity AV graft circuit that had never been previously stented. Both patent and thrombosed AV access circuits were retrospectively analyzed. Within the bare metal stent group, 20 of 32 AV grafts were thrombosed at initial presentation compared to 18 of 29 AV grafts in the covered stent group. Results: Thirty-two bare metal stents and 29 covered stents were deployed across the venous anastomosis. The 3, 6, and 12 months primary access patency rates for bare metal stents were not significantly different than for covered stents: 50, 41, and 22 % compared to 59, 52, and 29 %, respectively (p = 0.21). The secondary patency rates were also not significantly different: 78, 78, and 68 % for bare metal stents compared to 76, 69, and 61 % for covered stents, respectively (p = 0.85). However, covered stents demonstrated a higher primary stent patency rate than bare metal stents: 100, 85, and 70 % compared to 75, 67, and 49 % at 3, 6, and 12 months (p < 0.01). Conclusion: The primary and secondary access patency rates after deployment of bare metal versus covered stents at the venous anastomosis were not significantly different. However, bare metal stents developed in-stent stenoses significantly sooner.

Outcomes of Prosthetic Hemodialysis Grafts after Deployment of Bare Metal versus Covered Stents at the Venous Anastomosis

International Nuclear Information System (INIS)

Kim, Charles Y.; Tandberg, Daniel J.; Rosenberg, Michael D.; Miller, Michael J.; Suhocki, Paul V.; Smith, Tony P.

2012-01-01

Purpose: To compare postintervention patency rates after deployment of bare metal versus covered stents across the venous anastomosis of prosthetic arteriovenous (AV) grafts. Methods: Review of our procedural database over a 6 year period revealed 377 procedures involving stent deployment in an AV access circuit. After applying strict inclusion criteria, our study group consisted of 61 stent deployments in 58 patients (median age 58 years, 25 men, 33 women) across the venous anastomosis of an upper extremity AV graft circuit that had never been previously stented. Both patent and thrombosed AV access circuits were retrospectively analyzed. Within the bare metal stent group, 20 of 32 AV grafts were thrombosed at initial presentation compared to 18 of 29 AV grafts in the covered stent group. Results: Thirty-two bare metal stents and 29 covered stents were deployed across the venous anastomosis. The 3, 6, and 12 months primary access patency rates for bare metal stents were not significantly different than for covered stents: 50, 41, and 22 % compared to 59, 52, and 29 %, respectively (p = 0.21). The secondary patency rates were also not significantly different: 78, 78, and 68 % for bare metal stents compared to 76, 69, and 61 % for covered stents, respectively (p = 0.85). However, covered stents demonstrated a higher primary stent patency rate than bare metal stents: 100, 85, and 70 % compared to 75, 67, and 49 % at 3, 6, and 12 months (p < 0.01). Conclusion: The primary and secondary access patency rates after deployment of bare metal versus covered stents at the venous anastomosis were not significantly different. However, bare metal stents developed in-stent stenoses significantly sooner.

Pulmonary Arteriovenous Fistula: Clinical and Histologic Spectrum of Four Cases

Directory of Open Access Journals (Sweden)

Soomin Ahn

2016-09-01

Full Text Available Pulmonary arteriovenous fistula (PAVF is abnormally dilated vessels that provide a right-to-left shunt between pulmonary artery and pulmonary vein and is clinically divided into simple and complex type. Here, we report four cases of surgically resected sporadic PAVFs presenting various clinical and histologic spectrums. Cases 1 (a 57-old-female and 2 (a 54-old-female presented as incidentally identified single aneurysmal fistulas and the lesions were surgically removed without complication. On the other hand, case 3 (an 11-old-male showed diffuse dilated vascular sacs involving both lungs and caused severe hemodynamic and pulmonary dysfunction. Embolization and surgical resection of the main lesion failed to relieve the symptoms. Case 4 (a 36-old-male had a localized multiloculated cyst clinically mimicking congenital cystic adenomatoid malformation. Microscopically, the lesion consisted of dilated thick vessels, consistent with the diagnosis of fistulous arteriovenous malformation/hemangioma.

RASA1 analysis guides management in a family with capillary malformation-arteriovenous malformation.

Science.gov (United States)

Flore, Leigh Anne; Leon, Eyby; Maher, Tom A; Milunsky, Jeff M

2012-06-01

Capillary malformation-arteriovenous malformation (CM-AVM; MIM 60354) is an autosomal dominant disorder characterized by multifocal cutaneous capillary malformations, often in association with fast-flow vascular lesions, which may be cutaneous, subcutaneous, intramuscular, intraosseus, or cerebral arteriovenous malformations or arteriovenous fistulas. CM-AVM results from heterozygous mutations in the RASA1 gene. Capillary malformations of the skin are common, and clinical examination alone may not be able to definitively diagnose-or exclude- CM-AVM. We report a family in which the proband was initially referred for a genetic evaluation in the neonatal period because of the presence of a cardiac murmur and minor dysmorphic features. Both he and his mother were noted to have multiple capillary malformations on the face, head, and extremities. Echocardiography revealed dilated head and neck vessels and magnetic resonance imaging and angiography of the brain revealed a large infratentorial arteriovenous fistula, for which he has had two embolization procedures. RASA1 sequence analysis revealed a heterozygous mutation, confirming his diagnosis of CM-AVM. We established targeted mutation analysis for the proband's mother and sister, the latter of whom is a healthy 3-year-old whose only cutaneous finding is a facial capillary malformation. This revealed that the proband's mother is also heterozygous for the RASA1 mutation, but his sister is negative. Consequently, his mother will undergo magnetic resonance imaging and angiography screening for intracranial and spinal fast-flow lesions, while his sister will require no imaging or serial evaluations. Targeted mutation analysis has been offered to additional maternal family members. This case illustrates the benefit of molecular testing in diagnosis and making screening recommendations for families with CM-AVM.

Improved patency and reduced intimal hyperplasia in PTFE grafts with luminal immobilized heparin compared with standard PTFE grafts at six months in a sheep model.

Science.gov (United States)

Pedersen, G; Laxdal, E; Ellensen, V; Jonung, T; Mattsson, E

2010-06-01

The aim of this study was to compare the performance of polytetrafluoroethylene (PTFE) grafts with luminal coating of immobilized heparin to that of standard PTFE grafts at six months. Twenty-eight common carotid arteries in fourteen sheep were bypassed with heparin-coated PTFE grafts (6 mm diameter, 6 cm length) on one side and standard PTFE grafts on the other. The grafts were explanted after six months. The thickness of intimal hyperplasia (IH) in open grafts was measured with histomorphometrical methods. Two of 14 heparinized PTFE grafts and nine of 14 grafts in the control PTFE-group were occluded at explantation (P=0.006). Six-month patency rates for heparinized PTFE grafts and for standard PTFE grafts were 86% and 36%, respectively. Mean graft anastomotic IH thickness in open grafts were 0.074 mm for heparinized PTFE grafts and 0.259 mm for PTFE-grafts (P=0.006). PTFE grafts with luminal coating containing immobilized heparin had significantly better patency and recruited less intimal hyperplasia than standard PTFE grafts at six months.

Constitutive modeling of coronary artery bypass graft with incorporated torsion

Czech Academy of Sciences Publication Activity Database

Horný, L.; Chlup, Hynek; Žitný, R.; Adámek, T.

2009-01-01

Roč. 49, č. 2 (2009), s. 273-277 ISSN 0543-5846 R&D Projects: GA ČR(CZ) GA106/08/0557 Institutional research plan: CEZ:AV0Z20760514 Keywords : coronary artery bypass graft * constitutive model * digital image correlation Subject RIV: BJ - Thermodynamics Impact factor: 0.439, year: 2009 http://web.tuke.sk/sjf-kamam/mmams2009/contents.pdf

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.

A case report of spinal dural arteriovenous fistula: origins, determinants, and consequences of abnormal vascular malformations

OpenAIRE

Zakhary, Sherry M.; Hoehmann, Christopher L.; Cuoco, Joshua A.; Hitscherich, Kyle; Alam, Hamid; Torres, German

2017-01-01

A spinal dural arteriovenous fistula is an abnormally layered connection between radicular arteries and venous plexus of the spinal cord. This vascular condition is relatively rare with an incidence of 5–10 cases per million in the general population. Diagnosis of spinal dural arteriovenous fistula is differentiated by contrast-enhanced magnetic resonance angiography or structural magnetic resonance imaging, but a definitive diagnosis requires spinal angiography methods. Here, we report a cas...

Cardiac failure due to arteriovenous fistula with brachiocephalic stenosis: a gated heart case study

International Nuclear Information System (INIS)

Abel, G.; Irish, A.; Henderson, A.; Lenzo, N.

2003-01-01

Full text: There are numerous causes of cardiac failure of which the commonest in our community include ischaemic cardiomyopathy, post-viral cardiomyopathy, alcohol-induced cardiomyopathy and drug-induced cardiomyopathy. All these entities cause low output cardiac failure however high output cardiac failure is also well recognised. This includes heart failure related to such conditions as hyperthyroidism, anaemia, pregnancy, beri-beri, and Paget's disease. A rare cause of high output cardiac failure is an arteriovenous fistula. We present an unusual case of a patient with end-stage renal failure on haemodialysis who developed extensive dilatation of their left arm arteriovenous fistula secondary to bachiocephalic vein stenosis. The labelled red blood cell gated heart blood pool study demonstrated decreased left ventricular function and extensive pooling of blood within the tortuous dilated left arm vessels. A follow-up study post-ligation of the arteriovenous fistula showed improvement of the left ventricular ejection fraction. The associated contrast venography findings are also demonstrated. Copyright (2003) The Australian and New Zealand Society of Nuclear Medicine Inc

Long-Term Follow-up After Embolization of Pulmonary Arteriovenous Malformations with Detachable Silicone Balloons

International Nuclear Information System (INIS)

Andersen, Poul Erik; Kjeldsen, Anette D.

2008-01-01

Long-term follow-up results after embolization of 13 pulmonary arteriovenous malformations in 10 patients by use of 14 detachable silicone balloons are given. Patients were followed for a mean of 99 months (range, 63-123 months) with chest x-rays and for a mean of 62 months (range, 3-101 months) with pulmonary angiography. Fifty-four percent of the balloons were deflated at latest radiographic chest film follow-up, but at pulmonary angiographic follow-up all embolized malformations were without flow irrespective of whether or not the balloons were visible. Detachable silicone balloons are not available anymore, but use of these balloons for embolization of pulmonary arteriovenous malformations has been shown to be a safe and precise method, with immediate occlusion of the feeding artery and with long-lasting occlusion, even though many balloons deflate with time, leaving a fibrotic scar replacing the pulmonary arteriovenous malformation. No case of recanalization has been discovered, and these results seem to justify a reduced number of controls of these balloon-embolized malformations

Suppressing unsteady flow in arterio-venous fistulae

Science.gov (United States)

Grechy, L.; Iori, F.; Corbett, R. W.; Shurey, S.; Gedroyc, W.; Duncan, N.; Caro, C. G.; Vincent, P. E.

2017-10-01

Arterio-Venous Fistulae (AVF) are regarded as the "gold standard" method of vascular access for patients with end-stage renal disease who require haemodialysis. However, a large proportion of AVF do not mature, and hence fail, as a result of various pathologies such as Intimal Hyperplasia (IH). Unphysiological flow patterns, including high-frequency flow unsteadiness, associated with the unnatural and often complex geometries of AVF are believed to be implicated in the development of IH. In the present study, we employ a Mesh Adaptive Direct Search optimisation framework, computational fluid dynamics simulations, and a new cost function to design a novel non-planar AVF configuration that can suppress high-frequency unsteady flow. A prototype device for holding an AVF in the optimal configuration is then fabricated, and proof-of-concept is demonstrated in a porcine model. Results constitute the first use of numerical optimisation to design a device for suppressing potentially pathological high-frequency flow unsteadiness in AVF.

Radiological evaluation with Doppler sonography and multidetector CT angiography in congenital hepatic arteriovenous malformation in a newborn

Energy Technology Data Exchange (ETDEWEB)

Adaletli, Ibrahim; Kurugoglu, Sebuh; Kilic, Fahrettin [Istanbul University, Department of Radiology, Cerrahpasa Medical Faculty (Turkey); Senyuz, Osman F. [Istanbul University, Department of Paediatric Surgery, Cerrahpasa Medical Faculty (Turkey); Dervisoglu, Sergulen [Istanbul University, Department of Pathology, Cerrahpasa Medical Faculty (Turkey)

2006-11-15

Although hepatic arteriovenous malformations are rarely reported, they frequently have life-threatening complications such as cardiac failure and are associated with a high mortality rate. Consequently, accurate prenatal and early postnatal diagnosis is important and therapeutic procedures depend on the imaging features. We report the early postnatal sonographic, Doppler sonographic, multidetector CT and CT angiography findings of a congenital hepatic arteriovenous malformation in a newborn. (orig.)

Radiological evaluation with Doppler sonography and multidetector CT angiography in congenital hepatic arteriovenous malformation in a newborn

International Nuclear Information System (INIS)

Adaletli, Ibrahim; Kurugoglu, Sebuh; Kilic, Fahrettin; Senyuz, Osman F.; Dervisoglu, Sergulen

2006-01-01

Although hepatic arteriovenous malformations are rarely reported, they frequently have life-threatening complications such as cardiac failure and are associated with a high mortality rate. Consequently, accurate prenatal and early postnatal diagnosis is important and therapeutic procedures depend on the imaging features. We report the early postnatal sonographic, Doppler sonographic, multidetector CT and CT angiography findings of a congenital hepatic arteriovenous malformation in a newborn. (orig.)

Blood pressure shifts resulting from a concealed arteriovenous fistula associated with an iliac aneurysm: a case report.

Science.gov (United States)

Doi, Shintaro; Motoyama, Yoshiaki; Ito, Hiromi

2016-01-01

A solitary iliac aneurysm (SIA) is more uncommon than an abdominal aortic aneurysm. The aneurysm is located in the deep pelvis and is diagnosed when it reaches a large size with symptoms of compression around adjacent structures and organs or when it ruptures. A definite diagnosis of an arteriovenous fistula (AVF) associated with a SIA is difficult preoperatively because there might not be enough symptoms and time for diagnosis. Here, we present a patient with asymptomatic rupture of SIA into the common iliac vein with characteristic blood pressure shifts. A 41-year-old man with a huge SIA underwent aortobifemoral graft replacement. Preoperatively, his blood pressure showed characteristic shifts for one or two heartbeats out of five beats, indicating that an AVF was present and that the shunt was about to having a high flow. During surgery, an AVF associated with the SIA was found to be concealed owing to compression from the huge iliac artery aneurysm, and the shunt showed a high flow, resulting in shock during the surgery. No complications were noted after aortobifemoral graft replacement. Postoperatively, we noted an enhanced paravertebral vein on computed tomography (CT), which indicated the presence of an AVF. Definite diagnosis of an AVF offers advantages in surgical and anesthetic management. We emphasize that a large SIA can push the iliac vein and occlude an AVF laceration, concealing the enhancement of the veins in the arterial phase on CT. Blood pressure shifts might predict the existence of a concealed AVF that has a large shunt. Even if the vena cava and the iliac veins are not enhanced on CT, anesthesiologists should carefully determine whether their distal branches are enhanced.

Paraspinal arteriovenous malformation Onyx embolization via an Ascent balloon.

Science.gov (United States)

Martínez-Galdámez, Mario; Rodriguez-Arias, Carlos A; Utiel, Elena; Arreba, Emilio; Gonzalo, Miguel; Arenillas, Juan F

2014-04-01

Purely extradural lumbar spinal arteriovenous malformations (AVMs) are rare lesions that have diverse presentations and imaging features. The treatment of a symptomatic high flow paraspinal AVM with multiple feeders remains a challenge. We report the first use of an Ascent balloon (dual lumen balloon catheter) to deliver Onyx with excellent penetration to a paraspinal AVM.

Myocardial abscess as a complication of an infected arteriovenous fistula: autopsy report

Directory of Open Access Journals (Sweden)

Cristiane Rúbia Ferreira

2011-09-01

Full Text Available Myocardial abscess is a severe and life-threatening infectious complication thatis commonly but not exclusively associated with infective endocarditis. It mayalso be developed in necrotic myocardial tissue, post trauma, in septic burnpatients, in transplanted heart, in ventricular aneurysm and post angioplasty.Patients on hemodialysis are prone to bacteremia, and infectious complicationsoccur in 48-73% of cases. Myocardial abscess is a rare complication of aninfected arteriovenous fistula. We present an autopsy report of a hemodialysispatient who had an arteriovenous fistula with a polytetrafluoroethylene graftwhere a local infection developed. The patient presented with fever and toxemia.On post-admission day 2, he unexpectedly suffered sudden cardiopulmonaryarrest and died. The autopsy revealed a myocardial abscess, near a branch ofthe left coronary artery, with septic embolism.

Transseptal Guidewire Stabilization for Device Closure of a Large Pulmonary Arteriovenous Malformation

International Nuclear Information System (INIS)

Joseph, George; Kunwar, Brajesh Kumar

2013-01-01

A 46-year-old man presenting with massive hemoptysis was found to have a large pulmonary arteriovenous malformation (PAVM) in the right lung. Closure of the PAVM with an Amplatzer-type duct occluder was hampered by inability to advance the device delivery sheath into the PAVM due to vessel tortuosity and inadequate guidewire support. Atrial septal puncture was performed and a femorofemoral arteriovenous guidewire loop through the right pulmonary artery, PAVM, and left atrium was created. Traction on both ends of the guidewire loop allowed advancement of the device delivery sheath into the PAVM and successful completion of the procedure. Transseptal guidewire stabilization can be a valuable option during device closure of large PAVMs when advancement, stability, or kinking of the device delivery sheath is an issue.

Arteriovenous thrombosis in chronic renal failure patients receving renal replacement therapy

International Nuclear Information System (INIS)

Shoaib, M.; Naz, A.

2008-01-01

To determine the frequency of thrombotic complications and to identify factors associated with arteriovenous thrombosis in patients of chronic renal failure receiving renal replacement therapy. Of the 3000 patients evaluated, 61 End Stage Renal Disease (ESRD) patients on regular dialysis, having recent renal transplant, were selected for the study after informed consent. These patients had arteriovenous thrombosis with temporary central lines thrombosis and vascular access problems. Cases of congenital or acquired thrombotic disorders, e.g. with malignancy, DIC, liver disease, systemic lupus erythematosus or other immunologic diseases, pregnancy or women using oral contraceptives, were excluded. Similarly, patients taking any type of anticoagulant therapy during the preceding one week were not included in the study. Findings were recorded in a structured questionnaire. Laboratory analysis was done after clinical and radiological evaluation. Thrombophilia screening included antithrombin, protein C, protein S deficiencies and lupus anticoagulant. Forty-seven out of 61 patients selected were positive for thrombophilia screening with protein C deficiency in 26.2%, protein S deficiency in 16.3%, antithrombin in 5%, lupus anticoagulant in 13.1% and combined deficiency was observed in 16.3%. Of the 3000 patients, 61 with frequency of 2% were found to be deficient in one or had combined deficiency of these. Thus, the study of ESRD patients presenting with arteriovenous thromboembolism emphasizes the need to reconsider the perception that this clinical entity is rare and requires further studies. (author)

Functional integration of grafted neural stem cell-derived dopaminergic neurons monitored by optogenetics in an in vitro Parkinson model.

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Jan Tønnesen

Full Text Available Intrastriatal grafts of stem cell-derived dopamine (DA neurons induce behavioral recovery in animal models of Parkinson's disease (PD, but how they functionally integrate in host neural circuitries is poorly understood. Here, Wnt5a-overexpressing neural stem cells derived from embryonic ventral mesencephalon of tyrosine hydroxylase-GFP transgenic mice were expanded as neurospheres and transplanted into organotypic cultures of wild type mouse striatum. Differentiated GFP-labeled DA neurons in the grafts exhibited mature neuronal properties, including spontaneous firing of action potentials, presence of post-synaptic currents, and functional expression of DA D₂ autoreceptors. These properties resembled those recorded from identical cells in acute slices of intrastriatal grafts in the 6-hydroxy-DA-induced mouse PD model and from DA neurons in intact substantia nigra. Optogenetic activation or inhibition of grafted cells and host neurons using channelrhodopsin-2 (ChR2 and halorhodopsin (NpHR, respectively, revealed complex, bi-directional synaptic interactions between grafted cells and host neurons and extensive synaptic connectivity within the graft. Our data demonstrate for the first time using optogenetics that ectopically grafted stem cell-derived DA neurons become functionally integrated in the DA-denervated striatum. Further optogenetic dissection of the synaptic wiring between grafted and host neurons will be crucial to clarify the cellular and synaptic mechanisms underlying behavioral recovery as well as adverse effects following stem cell-based DA cell replacement strategies in PD.

Congenital hepatic arteriovenous fistula with intrahepatic portosystemic shunt and aortic stenosis in a dog

International Nuclear Information System (INIS)

Koide, K.; Koide, Y.; Wada, Y.; Nakaniwa, S.; Yamane, Y.

2004-01-01

Examination of a 2-month-old male golden retriever presented to the hospital revealed malnutrition, ascites, cardiac murmur and hyperammonemia. Identification of subaortic stenosis and hepatic arteriovenous fistula was made through ultrasonography and angiocardiography. In addition, intrasurgical mesenteric portography showed an intrahepatic portosystemic shunt. The dog did not show portal hypertension and secondary multiple extrahepatic portosystemic shunts. Surgical correction was attempted after medical treatment. The hepatic artery branch which was connected to the hepatic arteriovenous fistula was separated, and completely ligated using silk ligature. However, the separation of the intrahepatic shunt blood vessel was unsuccessful and the dog died 15 hr postoperatively

Venous hemodynamics of arteriovenous meningeal fistulas in the posterior cranial fossa

International Nuclear Information System (INIS)

Brainin, M.; Samec, P.

1983-01-01

The etiology of arteriovenous meningeal fistulas (AVMFs) of the posterior fossa often remains unclear. Analyses of three personal cases, however, suggest a change in venous hemodynamics due to a primary lesion, the cases being of sinus thrombosis, intracerebral abcess with oedema and arteriovenous malformation. It is suggested that increase of venous pressure in the posterior fossa leads to increased drainage and, consequently, to dilatation of infratentorial veins and of meningeal branches of the external carotid and vertebral artery. Clinical findings and anatomical facts underlying AVMF lesions tend to confirm the view that the concept of a congenital malformation decompensating with age cannot be upheld for all AVMFs, especially when located in the posterior fossa and when clinical symptoms arise in middle age. It is proposed that a pressure activated mechanism of growth results in widening of normally insignificantly small dural vessels. (orig.)

Radiation dermatitis after spinal arteriovenous malformation embolization: case report

International Nuclear Information System (INIS)

Carstens, G.J.; Horowitz, M.B.; Purdy, P.D.; Pandya, A.G.

1996-01-01

Few cases of radiation injury related to lengthy interventional neuroradiologic procedures have been reported, although concern has been heightened, as evidenced by a 1994 FDA Public Health Advisory. We report a case of radiation-induced dermatitis in a patient undergoing multiple diagnostic and embolization procedures for treatment of a spinal arteriovenous malformation. (orig.). With 2 figs

Augmentation of Distal Biceps Repair With an Acellular Dermal Graft Restores Native Biomechanical Properties in a Tendon-Deficient Model.

Science.gov (United States)

Conroy, Christine; Sethi, Paul; Macken, Craig; Wei, David; Kowalsky, Marc; Mirzayan, Raffy; Pauzenberger, Leo; Dyrna, Felix; Obopilwe, Elifho; Mazzocca, Augustus D

2017-07-01

The majority of distal biceps tendon injuries can be repaired in a single procedure. In contrast, complete chronic tears with severe tendon substance deficiency and retraction often require tendon graft augmentation. In cases with extensive partial tears of the distal biceps, a human dermal allograft may be used as an alternative to restore tendon thickness and biomechanical integrity. Dermal graft augmentation will improve load to failure compared with nonaugmented repair in a tendon-deficient model. Controlled laboratory study. Thirty-six matched specimens were organized into 1 of 4 groups: native tendon, native tendon with dermal graft augmentation, tendon with an attritional defect, and tendon with an attritional defect repaired with a graft. To mimic a chronic attritional biceps lesion, a defect was created by a complete tear, leaving 30% of the tendon's width intact. The repair technique in all groups consisted of cortical button and interference screw fixation. All specimens underwent cyclical loading for 3000 cycles and were then tested to failure; gap formation and peak load at failure were documented. The mean (±SD) load to failure (320.9 ± 49.1 N vs 348.8 ± 77.6 N, respectively; P = .38) and gap formation (displacement) (1.8 ± 1.4 mm vs 1.6 ± 1.1 mm, respectively; P = .38) did not differ between the native tendon groups with and without graft augmentation. In the tendon-deficient model, the mean load to failure was significantly improved with graft augmentation compared with no graft augmentation (282.1 ± 83.8 N vs 199.7 ± 45.5 N, respectively; P = .04), while the mean gap formation was significantly reduced (1.2 ± 1.0 mm vs 2.7 ± 1.4 mm, respectively; P = .04). The mean load to failure of the deficient tendon with graft augmentation (282.1 N) compared with the native tendon (348.8 N) was not significantly different ( P = .12). This indicates that the native tendon did not perform differently from the grafted deficient tendon. In a tendon

Hemodynamic analysis of sequential graft from right coronary system to left coronary system.

Science.gov (United States)

Wang, Wenxin; Mao, Boyan; Wang, Haoran; Geng, Xueying; Zhao, Xi; Zhang, Huixia; Xie, Jinsheng; Zhao, Zhou; Lian, Bo; Liu, Youjun

2016-12-28

Sequential and single grafting are two surgical procedures of coronary artery bypass grafting. However, it remains unclear if the sequential graft can be used between the right and left coronary artery system. The purpose of this paper is to clarify the possibility of right coronary artery system anastomosis to left coronary system. A patient-specific 3D model was first reconstructed based on coronary computed tomography angiography (CCTA) images. Two different grafts, the normal multi-graft (Model 1) and the novel multi-graft (Model 2), were then implemented on this patient-specific model using virtual surgery techniques. In Model 1, the single graft was anastomosed to right coronary artery (RCA) and the sequential graft was adopted to anastomose left anterior descending (LAD) and left circumflex artery (LCX). While in Model 2, the single graft was anastomosed to LAD and the sequential graft was adopted to anastomose RCA and LCX. A zero-dimensional/three-dimensional (0D/3D) coupling method was used to realize the multi-scale simulation of both the pre-operative and two post-operative models. Flow rates in the coronary artery and grafts were obtained. The hemodynamic parameters were also showed, including wall shear stress (WSS) and oscillatory shear index (OSI). The area of low WSS and OSI in Model 1 was much less than that in Model 2. Model 1 shows optimistic hemodynamic modifications which may enhance the long-term patency of grafts. The anterior segments of sequential graft have better long-term patency than the posterior segments. With rational spatial position of the heart vessels, the last anastomosis of sequential graft should be connected to the main branch.

Functional integration of grafted neural stem cell-derived dopaminergic neurons monitored by optogenetics in an in vitro Parkinson model

DEFF Research Database (Denmark)

Tønnesen, Jan; Parish, Clare L; Sørensen, Andreas T

2011-01-01

Intrastriatal grafts of stem cell-derived dopamine (DA) neurons induce behavioral recovery in animal models of Parkinson's disease (PD), but how they functionally integrate in host neural circuitries is poorly understood. Here, Wnt5a-overexpressing neural stem cells derived from embryonic ventral...... of post-synaptic currents, and functional expression of DA D₂ autoreceptors. These properties resembled those recorded from identical cells in acute slices of intrastriatal grafts in the 6-hydroxy-DA-induced mouse PD model and from DA neurons in intact substantia nigra. Optogenetic activation...... using optogenetics that ectopically grafted stem cell-derived DA neurons become functionally integrated in the DA-denervated striatum. Further optogenetic dissection of the synaptic wiring between grafted and host neurons will be crucial to clarify the cellular and synaptic mechanisms underlying...

Graft function assessment in mouse models of single- and dual- kidney transplantation.

Science.gov (United States)

Wang, Lei; Wang, Ximing; Jiang, Shan; Wei, Jin; Buggs, Jacentha; Fu, Liying; Zhang, Jie; Liu, Ruisheng

2018-05-23

Animal models of kidney transplantation (KTX) are widely used in studying immune response of hosts to implanted grafts. Additionally, KTX can be used in generating kidney-specific knockout animal models by transplantation of kidneys from donors with global knockout of a gene to wild type recipients or vise verse. Dual kidney transplantation (DKT) provides a more physiological environment for recipients than single kidney transplantation (SKT). However, DKT in mice is rare due to technical challenges. In this study, we successfully performed DKT in mice and compared the hemodynamic response and graft function with SKT. The surgical time, complications and survival rate of DKT were not significantly different from SKT, where survival rates were above 85%. Mice with DKT showed less injury and quicker recovery with lower plasma creatinine (Pcr) and higher GFR than SKT mice (Pcr = 0.34 and 0.17 mg/dl in DKT vs. 0.50 and 0.36 mg/dl in SKT at 1 and 3 days, respectively; GFR = 215 and 131 µl/min for DKT and SKT, respectively). In addition, the DKT exhibited better renal functional reserve and long-term outcome of renal graft function than SKT based on the response to acute volume expansion. In conclusion, we have successfully generated a mouse DKT model. The hemodynamic responses of DKT better mimic physiological situations with less kidney injury and better recovery than SKT because of reduced confounding factors such as single nephron hyperfiltration. We anticipate DKT in mice will provide an additional tool for evaluation of renal significance in physiology and disease.

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 ...

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

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.

An Unusual Case Of Urinary Bladder Arteriovenous Malformation

LENUS (Irish Health Repository)

Gnanappiragasam, D

2016-07-01

A 45-year-old male presented with haematuria and urinary frequency. Computed Tomography (CT) urogram revealed gross thickening of the left bladder wall. Histology showed large vessels cuffed by eosinophonilic material suggestive of urinary bladder arteriovenous malformation (AVM). No further intervention was carried out as symptoms resolve after the resection. Follow up rigid cystoscopy and CT at 3 months showed resolution of all visible pathology and no evidence of recurrence.

Duplex sonography in the planning and evaluation of arteriovenous fistulae for haemodialysis

International Nuclear Information System (INIS)

Kerr, S.F.; Krishan, S.; Lapham, R.C.; Weston, M.J.

2010-01-01

This paper describes how to perform duplex sonography in the planning and evaluation of arteriovenous fistulae in haemodialysis patients, discusses its roles in these settings, and presents a review of commonly encountered complications.

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.

Vector velocity volume flow estimation: Sources of error and corrections applied for arteriovenous fistulas

DEFF Research Database (Denmark)

Jensen, Jonas; Olesen, Jacob Bjerring; Stuart, Matthias Bo

2016-01-01

radius. The error sources were also studied in vivo under realistic clinical conditions, and the theoretical results were applied for correcting the volume flow errors. Twenty dialysis patients with arteriovenous fistulas were scanned to obtain vector flow maps of fistulas. When fitting an ellipsis......A method for vector velocity volume flow estimation is presented, along with an investigation of its sources of error and correction of actual volume flow measurements. Volume flow errors are quantified theoretically by numerical modeling, through flow phantom measurements, and studied in vivo...

Pulmonary arterio-venous micro fistulae - Diagnostic

International Nuclear Information System (INIS)

Ebram, J.C.

1989-01-01

Four patients with pulmonary arterio-venous micro-fistulae - of which two were male (50%) - the ages varying from 10 to 43 (X sup(∼) = 22,7), were studied at the Cardiology Centre of the 6th Ward of Santa Casa da Misericordia Hospital in Rio de Janeiro. They were all basically suffering from Manson's Schistosomiasis, the hepato-splenic form in 3 cases (75%) and the Rendu Osler Weber disease with juvenile cirrhosis in 1 case (25%). All four of them had portal hypertension. The individual cases were clinically evaluate with X-rays, scintillographic and hemodynamic tests. (author)

Pediatric congenital vertebral artery arteriovenous malformation

International Nuclear Information System (INIS)

Shownkeen, Harish; Chenelle, Andrew G.; Origitano, Thomas C.; Bova, Davide

2003-01-01

Vertebral arteriovenous fistulas are rare in children and the congenital form has been seldom reported in the literature. Prior to using endovascular therapy techniques, only surgery was the main treatment. The most common endovascular treatment is through the use of detachable balloons. This report describes the clinical and radiological findings of a congenital vertebral artery fistula in a 20-month-old child. Balloons could not be safely employed; therefore, embolization was performed with Guglielmi detachable microcoils. We review the history and treatment of these lesions, their clinical presentation, and imaging features, including their outcome, with particular attention to the pediatric population. (orig.)

Creation of an iliac arteriovenous shunt lowers blood pressure in chronic obstructive pulmonary disease patients with hypertension.

LENUS (Irish Health Repository)

Faul, John

2014-01-28

Vasodilators are used with caution in patients with chronic obstructive pulmonary disease (COPD). We have developed a device for percutaneous arteriovenous shunt creation in the iliac region to increase cardiac output and oxygen delivery for patients with COPD. Although this device does not cause significant blood pressure changes in normotensive patients with COPD, we hypothesized that arteriovenous shunt creation might cause vasodilator effects in hypertensive patients because of a reduction in vascular resistance.

Congenital pelvic arteriovenous malformation: uncommon symptoms of lower limb venous hypertension.

Science.gov (United States)

Akimaro Kudo, F; Nishibe, T; Miyazaki, K; Flores, J; Yasuda, K

2001-12-01

Congenital pelvic arteriovenous malformations (AVMs) are rare and their clinical behavior is quite variable. A case of congenital pelvic AVM manifesting with unusual extrapelvic symptoms of ipsilateral leg pain is described. The causes of symptoms associated with congenital pelvic AVMs are discussed.

Complications following linear accelerator based stereotactic radiation for cerebral arteriovenous malformations

DEFF Research Database (Denmark)

Skjøth-Rasmussen, Jane; Roed, Henrik; Ohlhues, Lars

2010-01-01

Primarily, gamma knife centers are predominant in publishing results on arteriovenous malformations (AVM) treatments including reports on risk profile. However, many patients are treated using a linear accelerator-most of these at smaller centers. Because this setting is different from a large...

Magnetic resonance angiography of arteriovenous malformation in the brainstem

Energy Technology Data Exchange (ETDEWEB)

Oyama, Hirofumi; Kida, Yoshihisa; Kobayashi, Tatsuya; Tanaka, Takayuki; Iwakoshi, Takayasu; Kai, Osamu; Hirose, Mitsuhiko [Komaki City Hospital, Aichi (Japan)

1993-11-01

The magnetic resonance (MR) angiography appearance of arteriovenous malformation (AVM) in the tegmentum and pons is described. The interpeduncular perforating branches of the posterior cerebral artery and median pontine branches of the basilar artery were seen more clearly by MR angiography than by conventional angiography. MR angiography was very useful for the follow-up of AVM after stereotactic radiosurgery. (author).

Double Coaxial Microcatheter Technique for Glue Embolization of Renal Arteriovenous Malformations

International Nuclear Information System (INIS)

Uchikawa, Yoko; Mori, Kensaku; Shiigai, Masanari; Konishi, Takahiro; Hoshiai, Sodai; Ishigro, Toshitaka; Hiyama, Takashi; Nakai, Yasunobu; Minami, Manabu

2015-01-01

PurposeTo demonstrate the technical benefit of the double coaxial microcatheter technique for embolization of renal arteriovenous malformations (AVMs) with n-butyl cyanoacrylate and iodized oil (glue).Materials and MethodsSix consecutive patients (1 man and 5 women; mean age 61 years; range 44–77 years) with renal AVMs were included. Five patients had hematuria, and one had a risk of heart failure due to a large intrarenal arteriovenous shunt. All patients underwent transarterial embolization using glue and the double coaxial microcatheter technique with outer 2.6F and inner 1.9F microcatheters. After glue injection, the inner microcatheter was retracted, while the outer microcatheter was retained. We assessed the complications and clinical outcomes of this technique.ResultsTechnical success was achieved in all patients. In 9 sessions, 34 feeding arteries were embolized with glue using the double coaxial microcatheter technique, 1 was embolized with glue using a single microcatheter, and 2 were embolized with coils. The double coaxial microcatheter technique was useful for selecting small tortuous feeding arteries, preventing glue reflux to the proximal arteries, and approaching multiple feeding arteries without complete retraction of the microcatheters. As a minor complication, glue migrated into the venous system in four patients without any sequelae. In all patients, favorable clinical outcomes, including hematuria cessation in five patients and improvement of the large intrarenal arteriovenous shunt in one patient, were obtained without deterioration of renal function.ConclusionGlue embolization with the double coaxial microcatheter technique was useful for treating renal AVMs with multiple tortuous feeding arteries

Double Coaxial Microcatheter Technique for Glue Embolization of Renal Arteriovenous Malformations

Energy Technology Data Exchange (ETDEWEB)

Uchikawa, Yoko, E-mail: jauchikawa@gmail.com [University of Tsukuba Hospital, Department of Radiology (Japan); Mori, Kensaku, E-mail: moriken@md.tsukuba.ac.jp [University of Tsukuba, Department of Radiology, Faculty of Medicine (Japan); Shiigai, Masanari, E-mail: m-41gai@yahoo.co.jp [Tsukuba Medical Center Hospital, Department of Radiology (Japan); Konishi, Takahiro, E-mail: soratobukangaruu@gmail.com [University of Tsukuba Hospital, Department of Radiology (Japan); Hoshiai, Sodai, E-mail: hoshiai@sb4.so-net.ne.jp [Ibaraki Prefectural Central Hospital, Department of Radiology (Japan); Ishigro, Toshitaka, E-mail: suzutokei@gmail.com; Hiyama, Takashi, E-mail: med-tak@hotmail.com [University of Tsukuba Hospital, Department of Radiology (Japan); Nakai, Yasunobu, E-mail: nakaiya@tmch.or.jp [Tsukuba Medical Center Hospital, Department of Neurosurgery (Japan); Minami, Manabu, E-mail: mminami@md.tsukuba.ac.jp [University of Tsukuba, Department of Radiology, Faculty of Medicine (Japan)

2015-10-15

PurposeTo demonstrate the technical benefit of the double coaxial microcatheter technique for embolization of renal arteriovenous malformations (AVMs) with n-butyl cyanoacrylate and iodized oil (glue).Materials and MethodsSix consecutive patients (1 man and 5 women; mean age 61 years; range 44–77 years) with renal AVMs were included. Five patients had hematuria, and one had a risk of heart failure due to a large intrarenal arteriovenous shunt. All patients underwent transarterial embolization using glue and the double coaxial microcatheter technique with outer 2.6F and inner 1.9F microcatheters. After glue injection, the inner microcatheter was retracted, while the outer microcatheter was retained. We assessed the complications and clinical outcomes of this technique.ResultsTechnical success was achieved in all patients. In 9 sessions, 34 feeding arteries were embolized with glue using the double coaxial microcatheter technique, 1 was embolized with glue using a single microcatheter, and 2 were embolized with coils. The double coaxial microcatheter technique was useful for selecting small tortuous feeding arteries, preventing glue reflux to the proximal arteries, and approaching multiple feeding arteries without complete retraction of the microcatheters. As a minor complication, glue migrated into the venous system in four patients without any sequelae. In all patients, favorable clinical outcomes, including hematuria cessation in five patients and improvement of the large intrarenal arteriovenous shunt in one patient, were obtained without deterioration of renal function.ConclusionGlue embolization with the double coaxial microcatheter technique was useful for treating renal AVMs with multiple tortuous feeding arteries.

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.

Colour Doppler ultrasound assessment of well-functioning mature arteriovenous fistulas for haemodialysis access

International Nuclear Information System (INIS)

Pietura, Radoslaw; Janczarek, Marzena; Zaluska, Wojciech; Szymanska, Anna; Janicka, Lucyna; Skublewska-Bednarek, Anna; Szczerbo-Trojanowska, Malgorzata

2005-01-01

Background: A well-functioning mature arteriovenous fistula is essential for the maintenance of haemodialysis in patients with chronic renal failure. The Brescia-Cimino arteriovenous fistula has the best survival characteristics and low rate of complications. The most common reason of fistula failure is thrombosis caused by stenosis. Colour Doppler ultrasonography has proven to be effective in the assessment of anatomical vascular features. The majority of studies were done in patients with clinically presumed arteriovenous fistula complications. However, only limited data are available about the well-functioning mature arteriovenous fistulas. The purpose of the present study was to evaluate completely asymptomatic, mature arteriovenous fistulas with colour Doppler ultrasound. Materials and methods: From July 2001 to April 2003, we examined 139 patients with the end-stage renal disease. They were in the range of 19-79 years of age (mean, 46.7 years). The study included only the patients who met the following criteria: (1) no difficulties with haemodialysis (as reported by nurses); (2) normal venous diastolic blood pressure (<150 mmHg) at monthly evaluation; (3) normal urea clearance x time/urea volume of distribution; (4) blood cells count, plasma electrolytes, and liver function at monthly evaluation. The mean fistula age was 26 months (S.D. = 21.9). The mean time of dialysis therapy was 49 months. Thirty-eight percent patients had primary fistulas, 23%-secondary, 11%-third and 11%-fourth, 4%-fifth, 5%-sixth, and 8% patients had more than sixth. Results: There was no correlation between: (1) patient's age and fistula age; (2) patient's age and number of fistulas in one patient; (3) fistula age and number of fistulas in one patient; (4) localization of fistula and fistula age. There was a strong correlation between dialysis therapy period and number of fistulas in one patient. The mean flow volume was 1204.1 ml/min (S.D. = 554). It was significantly higher in the

A Case of De Novo Anterior Condylar Dural Arteriovenous Fistula Long after Curative Transvenous Embolization of Contralateral Anterior Condylar Arteriovenous Fistula

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Shinya Hagiwara

2016-01-01

Full Text Available We report on a 55-year-old man who developed a de novo DAVF in left ACC 5 years after curative transvenous embolization for DAVF in right ACC. Angiography revealed that the de novo lesion demonstrated more aggressive arteriovenous shunt flow than the initial lesion. Successful transvenous embolization was performed for also the second lesion. The authors describe the possible pathophysiological mechanisms and management strategies for this rare occurrence.

Hybrid liposomes showing enhanced accumulation in tumors as theranostic agents in the orthotopic graft model mouse of colorectal cancer.

Science.gov (United States)

Okumura, Masaki; Ichihara, Hideaki; Matsumoto, Yoko

2018-11-01

Hybrid liposomes (HLs) can be prepared by simply sonicating a mixture of vesicular and micellar molecules in a buffer solution. This study aimed to elucidate the therapeutic effects and ability of HLs to detect (diagnosis) cancer in an orthotopic graft mouse model of colorectal cancer with HCT116 cells for the use of HLs as theranostic agents. In the absence of a chemotherapeutic drug, HLs exhibited therapeutic effects by inhibiting the growth of HCT116 colorectal cancer cells in vitro, possibly through an increase in apoptosis. Intravenously administered HLs also caused a remarkable reduction in the relative cecum weight in an orthotopic graft mouse model of colorectal cancer. A decrease in tumor size in the cecal sections was confirmed by histological analysis using HE staining. TUNEL staining indicated an induction of apoptosis in HCT116 cells in the orthotopic graft mouse model of colorectal cancer. For the detection (diagnosis) of colorectal cancer by HLs, the accumulation of HLs encapsulating a fluorescent probe (ICG) was observed in HCT116 cells in the in vivo colorectal cancer model following intravenous administration. These data indicate that HLs can accumulate in tumor cells in the cecum of the orthotopic graft mouse model of colorectal cancer for a prolonged period of time, and inhibit the growth of HCT116 cells.

Arterio-venous flow between monochorionic twins determined during intra-uterine transfusion. Nonlinear decay of adult red blood cells

Energy Technology Data Exchange (ETDEWEB)

Gemert, Martin J C van; Wijngaard, Jeroen P H M van den [Laser Centre and Department of Obstetrics, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam (Netherlands); Pasman, Suzanne A; Vandenbussche, Frank P H A [Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Centre, Leiden (Netherlands); Lopriore, Enrico [Division of Neonatology, Department of Pediatrics, Leiden University Medical Centre, Leiden (Netherlands)], E-mail: m.j.vangemert@amc.uva.nl

2008-07-07

Recently, we derived equations relating the flow of adult red blood cells through a placental arterio-venous anastomosis with intra-uterine and post-natal measured adult hemoglobin concentrations. In this letter, we re-derived the equations, now including a more realistic nonlinear decay of adult red blood cells, and re-evaluated the measurement accuracy of the arterio-venous flow and the lifetime of the red blood cells. (letter to the editor)

Effect of Embolization Material in the Calculation of Dose Deposition in Arteriovenous Malformations

International Nuclear Information System (INIS)

De la Cruz, O. O. Galvan; Moreno-Jimenez, S.; Larraga-Gutierrez, J. M.; Celis-Lopez, M. A.

2010-01-01

In this work it is studied the impact of the incorporation of high Z materials (embolization material) in the dose calculation for stereotactic radiosurgery treatment for arteriovenous malformations. A statistical analysis is done to establish the variables that may impact in the dose calculation. To perform the comparison pencil beam (PB) and Monte Carlo (MC) calculation algorithms were used. The comparison between both dose calculations shows that PB overestimates the dose deposited. The statistical analysis, for the quantity of patients of the study (20), shows that the variable that may impact in the dose calculation is the volume of the high Z material in the arteriovenous malformation. Further studies have to be done to establish the clinical impact with the radiosurgery result.

Hot callusing for propagation of American beech by grafting

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David W. Carey; Mary E. Mason; Paul Bloese; Jennifer L. Koch

2013-01-01

To increase grafting success rate, a hot callus grafting system was designed and implemented as part of a multiagency collaborative project to manage beech bark disease (BBD) through the establishment of regional BBD-resistant grafted seed orchards. Five years of data from over 2000 hot callus graft attempts were analyzed using a logistic regression model to determine...

Identification of subgroups by risk of graft failure after paediatric renal transplantation: application of survival tree models on the ESPN/ERA-EDTA Registry.

Science.gov (United States)

Lofaro, Danilo; Jager, Kitty J; Abu-Hanna, Ameen; Groothoff, Jaap W; Arikoski, Pekka; Hoecker, Britta; Roussey-Kesler, Gwenaelle; Spasojević, Brankica; Verrina, Enrico; Schaefer, Franz; van Stralen, Karlijn J

2016-02-01

Identification of patient groups by risk of renal graft loss might be helpful for accurate patient counselling and clinical decision-making. Survival tree models are an alternative statistical approach to identify subgroups, offering cut-off points for covariates and an easy-to-interpret representation. Within the European Society of Pediatric Nephrology/European Renal Association-European Dialysis and Transplant Association (ESPN/ERA-EDTA) Registry data we identified paediatric patient groups with specific profiles for 5-year renal graft survival. Two analyses were performed, including (i) parameters known at time of transplantation and (ii) additional clinical measurements obtained early after transplantation. The identified subgroups were added as covariates in two survival models. The prognostic performance of the models was tested and compared with conventional Cox regression analyses. The first analysis included 5275 paediatric renal transplants. The best 5-year graft survival (90.4%) was found among patients who received a renal graft as a pre-emptive transplantation or after short-term dialysis (2.2 years). The Cox model including both pre-transplant factors and tree subgroups had a significantly better predictive performance than conventional Cox regression (P 30 mL/min/1.73 m(2) and dialysis 20 months). Also in this case combining tree findings and clinical factors improved the predictive performance as compared with conventional Cox model models (P tree model to be an accurate and attractive tool to predict graft failure for patients with specific characteristics. This may aid the evaluation of individual graft prognosis and thereby the design of measures to improve graft survival in the poor prognosis groups. © The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Fabrication of custom-shaped grafts for cartilage regeneration.

Science.gov (United States)

Koo, Seungbum; Hargreaves, Brian A; Gold, Garry E; Dragoo, Jason L

2010-10-01

to create a custom-shaped graft through 3D tissue shape reconstruction and rapid-prototype molding methods using MRI data, and to test the accuracy of the custom-shaped graft against the original anatomical defect. An iatrogenic defect on the distal femur was identified with a 1.5 Tesla MRI and its shape was reconstructed into a three-dimensional (3D) computer model by processing the 3D MRI data. First, the accuracy of the MRI-derived 3D model was tested against a laser-scan based 3D model of the defect. A custom-shaped polyurethane graft was fabricated from the laser-scan based 3D model by creating custom molds through computer aided design and rapid-prototyping methods. The polyurethane tissue was laser-scanned again to calculate the accuracy of this process compared to the original defect. The volumes of the defect models from MRI and laser-scan were 537 mm3 and 405 mm3, respectively, implying that the MRI model was 33% larger than the laser-scan model. The average (±SD) distance deviation of the exterior surface of the MRI model from the laser-scan model was 0.4 ± 0.4 mm. The custom-shaped tissue created from the molds was qualitatively very similar to the original shape of the defect. The volume of the custom-shaped cartilage tissue was 463 mm3 which was 15% larger than the laser-scan model. The average (±SD) distance deviation between the two models was 0.04 ± 0.19 mm. This investigation proves the concept that custom-shaped engineered grafts can be fabricated from standard sequence 3-D MRI data with the use of CAD and rapid-prototyping technology. The accuracy of this technology may help solve the interfacial problem between native cartilage and graft, if the grafts are custom made for the specific defect. The major source of error in fabricating a 3D custom-shaped cartilage graft appears to be the accuracy of a MRI data itself; however, the precision of the model is expected to increase by the utilization of advanced MR sequences with higher magnet

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.

Challenges in the management of massive intraorbital and hemifacial arteriovenous malformation as causing life-threatening epistaxis

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Anura Michelle Manuel

2017-03-01

Full Text Available Arteriovenous malformations are congenital lesions that may evolve with time and manifest in a plethora of presentations. They can occur as torrential epistaxis when it extensively involves the facial region. Multi-imaging modalities are available to assist in characterizing the structure of the lesion as well as its location and extent. This complex disease requires a multidisciplinary team approach with preoperative embolization and surgery. We present a rare cause of life-threatening epistaxis in a gentleman with a longstanding orbital and hemifacial arteriovenous malformation and discuss the complexities involved in its management.

A case of pancreatic arteriovenous malformation with portal hypertension: treatment with transjuguIar intrahepatic portosystemic shunt

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Kim, Seong Hoon; Kim, Young Whan; Kim, Yong Joo [School of Medicine, Kyungpook National Univ., Daegu (Korea, Republic of)

2004-03-01

Arteriovenous malformation of the pancreas is a rare disease, and it is manifested by gastrointestinal bleeding and/or portal hypertension. Surgery is definitely the treatment of choice at the early stage of the disease, and a transcatheter embolization is an alternative treatment for the control of bleeding and if the lesion is surgically inaccessible. We describe a 62-year-old man who had refractory ascites and esophageal variceal bleeding caused by a pancreatic arteriovenous malformation associated with portal hypertension; this was successfully treated by a transjugular intrahepatic portosystemic shunt.

A case of pancreatic arteriovenous malformation with portal hypertension: treatment with transjuguIar intrahepatic portosystemic shunt

International Nuclear Information System (INIS)

Kim, Seong Hoon; Kim, Young Whan; Kim, Yong Joo

2004-01-01

Arteriovenous malformation of the pancreas is a rare disease, and it is manifested by gastrointestinal bleeding and/or portal hypertension. Surgery is definitely the treatment of choice at the early stage of the disease, and a transcatheter embolization is an alternative treatment for the control of bleeding and if the lesion is surgically inaccessible. We describe a 62-year-old man who had refractory ascites and esophageal variceal bleeding caused by a pancreatic arteriovenous malformation associated with portal hypertension; this was successfully treated by a transjugular intrahepatic portosystemic shunt

Effects of Hydroxyapatite on Bone Graft Resorption in an Experimental Model of Maxillary Alveolar Arch Defects

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Ozgur Pilanci

2013-06-01

Full Text Available Most commonly used treatments use autologous bone grafts to address bony defects in patients with cleft palate. Major disadvantages of autogenous bone grafts include donor site morbidity and resorption. Suggestions to overcome such problems include biomaterials that can be used alone or in combination with bone. We examined the effect of hydroxyapatite cement on bone graft resorption in a rabbit maxillary alveolar defect model. We divided 16 young adult albino New Zealand rabbits into two groups. A defect 1 cm wide was created in each rabbit's maxillary arch. In Group 1, the removed bone was disrupted, and the pieces were replaced in the defect. In the other group, the pieces were replaced after mixing (1:1 with hydroxyapatite cement. Quantitative computed tomographic evaluation of these grafts was performed in axial and coronal planes for each rabbit at 2 and 12 weeks. In axial images at 12 weeks, the group without cement showed mean bone resorption of 15%. In the cement group, a mean volumetric increase of 68% was seen. No resorption occurred when bone grafts were mixed with hydroxyapatite cement. [Arch Clin Exp Surg 2013; 2(3.000: 170-175

A rare case of spinal dural arteriovenous fistula

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Mariya Apostolova

2012-12-01

Full Text Available Spinal dural arteriovenous fistula (SDAVF is a rare vascular malformation of the spine. Only a limited number of cases of SDAVF have been reported in the current literature. We describe the case of a 74 year old male who presented with gradually progressive bilateral lower extremity weakness and bladder dysfunction and was subsequently diagnosed with SDAVF affecting both the thoracic and lumbar spine. The patient later underwent embolization with some improvement in his neurologic symptoms.

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

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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.

Adaptive significance of root grafting in trees

Energy Technology Data Exchange (ETDEWEB)

Loehle, C.; Jones, R.

1988-12-31

Root grafting has long been observed in forest trees but the adaptive significance of this trait has not been fully explained. Various authors have proposed that root grafting between trees contributes to mechanical support by linking adjacent root systems. Keeley proposes that this trait would be of greatest advantage in swamps where soils provide poor mechanical support. He provides as evidence a greenhouse study of Nyssa sylvatica Marsh in which seedlings of swamp provenance formed between-individual root grafts more frequently than upland provenance seedlings. In agreement with this within-species study, Keeley observed that arid zone species rarely exhibit grafts. Keeley also demonstrated that vines graft less commonly than trees, and herbs never do. Since the need for mechanical support coincides with this trend, these data seem to support his model. In this paper, the authors explore the mechanisms and ecological significance of root grafting, leading to predictions of root grafting incidence. Some observations support and some contradict the mechanical support hypothesis.

Monitoring arterio-venous differences of glucose and lactate in the anesthetized rat with or without brain damage with ultrafiltration and biosensor technology

NARCIS (Netherlands)

Leegsma-Vogt, G; Venema, K; Postema, F; Korf, J

2001-01-01

Continuous monitoring of arterio-venous glucose and lactate differences may serve as a diagnostic tool to assess normal brain function and brain pathology. We describe a method and some results obtained with arterio-venous measurements of glucose and lactate in the blood of the

PRFM enhance wound healing process in skin graft.

Science.gov (United States)

Reksodiputro, Mirta; Widodo, Dini; Bashiruddin, Jenny; Siregar, Nurjati; Malik, Safarina

2014-12-01

Facial plastic and reconstructive surgery often used skin graft on defects that cannot be covered primarily by a local flap. However, wound healing using skin graft is slow, most of the time the graft is contractured and the take of graft is not optimal. Platelet rich fibrin matrix (PRFM) is a new generation of concentrated platelets that produce natural fibrin and reported to speed up the healing process. Application of PRFM in the skin graft implants is expected to increase the survival of the graft. We used porcine as animal models to elucidate the effect of autologous PRFM on wound healing in full-thickness (FTSG) and split-thickness (STSG) skin grafts. Survival level of the skin graft was determined by using ImageJ software based on the formation of collagen type 1 and graft take. We observed that the use of PRFM in FTSG and STSG increased type 1 collagen formation. We also found that PRFM addition in STSG gave the best skin graft take. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Total Maxillary Reconstruction With a Bi-Paddle Double-Barrel Osteocutaneous Fibular Flap and Arteriovenous Saphenous Loop After a Globe-Sparing Total Maxillectomy Due to Osteosarcoma.

Science.gov (United States)

Tseng, Wan-Ling; Chang, Tzu-Yen; Hung, Kuo-Shu; Chen, Szu-Han; Hsiao, Jenn-Ren; Lee, Yao-Chou

2017-01-01

The titanium mesh or bone graft is usually used for orbital support after a globe-sparing total maxillectomy. However, its use can invite complications, such as infection, exposure, and absorption, especially for patients who require adjuvant radiotherapy. Here, the authors present a patient who received total maxillary reconstruction with an osteocutaneous fibular flap. A 53-year-old man with the diagnosis of maxillary osteosarcoma received a globe-sparing total maxillectomy. A bi-paddle double-barrel osteocutaneous fibular flap was used for orbital support, alveolar ridge recreation, and oro-sino-nasal separation. The short pedicle length inherent in the double-barrel design of the fibular flap was overcome by creating an arteriovenous saphenous loop. The postoperative recovery was uneventful. During the 9 months follow-up, the patient was tumor-free and satisfied with his appearance, speech, and intake functions. Reconstruction with a bi-paddle double-barrel osteocutaneous fibular flap after a globe-sparing total maxillectomy can achieve satisfactory aesthetic and functional results.

Transarterial embolisation of renal arteriovenous malformation: safety and efficacy in 24 patients with follow-up

International Nuclear Information System (INIS)

Eom, H.-J.; Shin, J.H.; Cho, Y.J.; Nam, D.H.; Ko, G.-Y.; Yoon, H.-K.

2015-01-01

Aim: To evaluate the efficacy and safety of renal artery embolisation (RAE) for renal arteriovenous malformation (AVM) as well as its outcomes. Materials and methods: The technical and clinical success rates, radiological and laboratory findings, and complications of RAE for 31 renal AVMs in 24 patients (M:F=9:15, mean age 46 years) at two separate medical institutions were retrospectively evaluated. Technical success was defined as complete occlusion of feeding arteries with no residual nidus seen on post-treatment angiography. Clinical failure was defined as recurrence of haematuria, presence of AVM on follow-up ultrasound or computed tomography, repeated RAE or surgery for the control of haematuria. Overall clinical success was defined as resolution haematuria or disappearance of AVM on follow-up imaging after single or multiple sessions of RAE. Results: Types of renal AVM were AVM, arterio-venous fistula (AVF) with intranidal aneurysm, and acquired AVF in 19, 1, and 4 patients, respectively. 18 patients (75%) underwent a single session of RAE, while 6 patients (25%) had two or more sessions of RAE. The level of embolisation was feeder, segmental artery, and main renal artery in 28 (90%), 2 (6%), and 1 (4%) procedures, respectively. Coil, n-butyl 2-cyanoacrylate, and polyvinyl alcohol were the most frequently chosen embolic materials and were used in 19, 14, and 8 procedures, respectively. The clinical success rate after initial RAE was 67% (16/24). Overall clinical success rate, including multisession RAE, was 88% (21/24). The technical success rate of 31 procedures was 65% (20/31). Among 11 technical failures in 10 patients, 4 achieved clinical success without additional RAE, 3 underwent second session RAE to achieve clinical success, and 3 patients underwent nephrectomy due to recurrence. Conclusion: RAE is a safe and effective treatment for renal AVM. Technical failure of RAE does not always lead to clinical failure and multiple embolisation sessions may be

The Effect of Platelet-Rich Plasma on Survival of the Composite Graft and the Proper Time of Injection in a Rabbit Ear Composite Graft Model

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Hyun Nam Choi

2014-11-01

Full Text Available BackgroundAdministration of growth factors has been associated with increased viability of composite grafts greater than 1-cm in diameter. Platelet-rich plasma (PRP contains many of the growth factors studied. In this study, we evaluate the effect of PRP injection on composite graft viability and the proper time for injection.MethodsA total of 24 New Zealand White rabbits were divided into four groups. Autologous PRP was injected into the recipient sites three days before grafting in group 1, on the day of grafting in group 2, and three days after grafting in group 3. Group 4 served as control without PRP administration. Auricular composite grafts of 3-cm diameter were harvested and grafted back into place after being rotated 180 degrees. Median graft viability and microvessel density were evaluated at day 21 of graft via macroscopic photographs and immunofluorescent staining, respectively.ResultsThe median graft survival rate was 97.8% in group 1, 69.2% in group 2, 55.7% in group 3, and 40.8% in the control group. The median vessel counts were 34 (per ×200 HPF in group 1, 24.5 in group 2, 19.5 in group 3, and 10.5 in the control group.ConclusionsThis study demonstrates that PRP administration is associated with increased composite graft viability. All experimental groups showed a significantly higher survival rate and microvessel density, compared with the control group. Pre-administration of PRP was followed by the highest graft survival rate and revascularization. PRP treatments are minimally invasive, fast, easily applicable, and inexpensive, and offer a potential clinical pathway to larger composite grafts.

Embolization of brain arteriovenous malformations using tracker catheter

International Nuclear Information System (INIS)

Kim, Sun Yong; Son, Mi Young; Jang, Jae Chun; Hwang, Mi Soo; Park, Bok Hwan

1990-01-01

With the recent advance in micro catheters, steerable guide wires, balloons, embolic materials and digital subtraction angiography (DSA), as well as technical refinements in endovascular surgery, there has been a revolution in therapeutic strategies for cerebral arteriovenous malformations (AVMs). We have performed super selective angiography and embolization with Tracker micro catheter about 12 cases of brain AVMs for therapeutic and preoperative aims. This micro catheter and guide wire provided high selectivity of feeding artery, greater maneuverability and useful for deliver various embolus materials

Grafted polymers with annealed excluded volume : a model for surfactant association in brushes

NARCIS (Netherlands)

Currie, E.P.K.; Fleer, G.J.; Cohen Stuart, M.A.; Borisov, O.V.

2000-01-01

We present an analytical self-consistent-field (SCF) theory for a neutral polymer brush (a layer of long polymer chains end-grafted to a surface) with annealed excluded volume interactions between the monomer units. This model mimics the reversible adsorption of solute molecules or aggregates, such

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

Hydrogen, a potential safeguard for graft-versus-host disease and graft ischemia-reperfusion injury?

Science.gov (United States)

Yuan, Lijuan; Shen, Jianliang

2016-01-01

Post-transplant complications such as graft-versus-host disease and graft ischemia-reperfusion injury are crucial challenges in transplantation. Hydrogen can act as a potential antioxidant, playing a preventive role against post-transplant complications in animal models of multiple organ transplantation. Herein, the authors review the current literature regarding the effects of hydrogen on graft ischemia-reperfusion injury and graft-versus-host disease. Existing data on the effects of hydrogen on ischemia-reperfusion injury related to organ transplantation are specifically reviewed and coupled with further suggestions for future work. The reviewed studies showed that hydrogen (inhaled or dissolved in saline) improved the outcomes of organ transplantation by decreasing oxidative stress and inflammation at both the transplanted organ and the systemic levels. In conclusion, a substantial body of experimental evidence suggests that hydrogen can significantly alleviate transplantation-related ischemia-reperfusion injury and have a therapeutic effect on graft-versus-host disease, mainly via inhibition of inflammatory cytokine secretion and reduction of oxidative stress through several underlying mechanisms. Further animal experiments and preliminary human clinical trials will lay the foundation for hydrogen use as a drug in the clinic. PMID:27652837

Challenges in the management of massive intraorbital and hemifacial arteriovenous malformation as causing life-threatening epistaxis.

Science.gov (United States)

Manuel, Anura Michelle; Kalimuthu, Santhi; Pathmanathan, Sitra Siri; Narayanan, Prepageran; Zainal Abidin, Zurina; Azmi, Khairul; Khalil, Alizan

2017-04-01

Arteriovenous malformations are congenital lesions that may evolve with time and manifest in a plethora of presentations. They can occur as torrential epistaxis when it extensively involves the facial region. Multi-imaging modalities are available to assist in characterizing the structure of the lesion as well as its location and extent. This complex disease requires a multidisciplinary team approach with preoperative embolization and surgery. We present a rare cause of life-threatening epistaxis in a gentleman with a longstanding orbital and hemifacial arteriovenous malformation and discuss the complexities involved in its management. Copyright © 2017. Published by Elsevier Taiwan.

Uterine arteriovenous malformation as a rare cause of genital bleeding

International Nuclear Information System (INIS)

Rodriguez, A.; Escartin, I.; Riazuelo, G.; Zaragozano, R.

2002-01-01

Uterine arteriovenous malformation is a rarely described entity, the presenting sign of which is usually genital bleeding. We report a case of this malformation in a woman of child-bearing age with a history of traumatic delivery and repeated subsequent curettage, describing the ultrasound, computed tomography and magnetic resonance findings, as well as the results of arteriography. (Author) 5 refs

Glucose pump test can be used to measure blood flow rate of native arteriovenous fistula in chronic hemodialysis.

Science.gov (United States)

Yavuz, Y C; Selcuk, N Y; Altıntepe, L; Güney, I; Yavuz, S

2018-01-01

In chronic hemodialysis patients, the low flow of vascular access may leads to inadequate dialysis, increased rate of hospitalization, morbidity, and mortality. It was found that surveillance should be performed for native arteriovenous (AV) should not be performed for AV graft in various studies. However, surveillance was done in graft AV fistulas in most studies. Doppler ultrasonography (US) was suggested for surveillance of AV fistulas by the last vascular access guideline of National Kidney Foundation Disease Outcomes Quality Initiative (NKF KDOQI). The aim of study is to determine whether glucose pump test (GPT) is used for surveillance of native AV fistulas by using Doppler US as reference. In 93 chronic hemodialysis patients with native AV fistula, blood flow rates were measured by Doppler US and GPT. For GPT, glucose was infused to 16 mL/min by pump and was measured at basal before the infusion and 11 s after the start of the infusion by glucometer. Doppler US was done by an expert radiologist. Used statistical tests were Mann-Whitney U test, Friedman test, regression analysis, and multiple regression analysis. Median values of blood flow rates measured by GPT (707 mL/min) and by Doppler US (700 mL/min) were not different (Z = 0.414, P = 0.678). Results of GPT and Doppler US measurements were positive correlate by regression analysis. The mean GPT value of diabetic patients (n = 39; 908 mL/min) was similar to that of nondiabetic patients (n = 54; 751 mL/min; Z = 1.31, P = 0.188). GPT values measured at three different dialysis session did not differ from each other that by Friedman test (F = 0.92, P = 0.39). This showed that GPT was stable and reliable. Glucose pump test can be used to measure blood flow rate of native AV fistula. GPT is an accurate and reliable test.

Extrasinusal dural arteriovenous malformations

International Nuclear Information System (INIS)

Piske, R.L.; Lasjaunias, P.

1988-01-01

Of 60 cases of dural arteriovenous malformations (DAVM) explored and treated in the Vascular Neuroradiology Unit of the Hospital of Bicetre between 1980 and 1986, 3 presented in an extrasinusal location: intraorbital, middle cerebral fossa and the region of the superior orbital fissure. We have not found any prior description of DAVMs in these regions in the literature. The classic concept that DAVMs rise in direct relationship with the dural sinuses is limited. We believe that these lesions may also developed in relationship with the venous drainage system of the sinuses and the venous drainage of the peripheral nervous system. We note that the superior ophthalmic vein which drains DAVMs of the orbit and the olfactory vein which drains DAVMs of the anterior cranial fossa and other veins that accompany the cranial nerves through the skull base have the characteristics of emissary veins. It may be that DAVMs can develop wherever veins follow a transosseous trajectory. (orig.)

Notch1 and 4 Signaling Responds to an Increasing Vascular Wall Shear Stress in a Rat Model of Arteriovenous Malformations

Directory of Open Access Journals (Sweden)

Jian Tu

2014-01-01

Full Text Available Notch signaling is suggested to promote the development and maintenance of cerebral arteriovenous malformations (AVMs, and an increasing wall shear stress (WSS contributes to AVM rupture. Little is known about whether WSS impacts Notch signaling, which is important for understanding the angiogenesis of AVMs. WSS was measured in arteriovenous fistulas (AVF surgically created in 96 rats at different time points over a period of 84 days. The expression of Notch receptors 1 and 4 and their ligands, Delta1 and 4, Jagged1, and Notch downstream gene target Hes1 was quantified in “nidus” vessels. The interaction events between Notch receptors and their ligands were quantified using proximity ligation assay. There was a positive correlation between WSS and time (r=0.97; P<0.001. The expression of Notch receptors and their ligands was upregulated following AVF formation. There was a positive correlation between time and the number of interactions between Notch receptors and their ligands aftre AVF formation (r=0.62, P<0.05 and a positive correlation between WSS and the number of interactions between Notch receptors and their ligands (r=0.87, P<0.005. In conclusion, an increasing WSS may contribute to the angiogenesis of AVMs by activation of Notch signaling.

Interventional treatment of pulmonary arteriovenous malformations

DEFF Research Database (Denmark)

Andersen, Poul Erik; Kjeldsen, Anette Drøhse

2010-01-01

Pulmonary arteriovenous malformations (PAVM) are congenital vascular communications in the lungs. They act as right to left shunts so that the blood running through these malformations is not oxygenated or filtered. These patients are typically hypoxaemic with exercise intolerance and are at high...... risk of paradoxical emboli to the brain and other organs. These malformations are most commonly seen in hereditary haemorrhagic telangiectasia (HHT) (Mb. Osler-Weber-Rendu syndrome). Nowadays, the generally accepted treatment strategy of first choice is embolization of the afferent arteries...... the functional level. Embolization is a well-established method of treating PAVM, with a significant effect on oxygenation of the blood. Screening for PAVM in patients at risk is recommended, especially in patients with HHT....

A multilayered polyurethane foam technique for skin graft immobilization.

Science.gov (United States)

Nakamura, Motoki; Ito, Erika; Kato, Hiroshi; Watanabe, Shoichi; Morita, Akimichi

2012-02-01

Several techniques are applicable for skin graft immobilization. Although the sponge dressing is a popular technique, pressure failure near the center of the graft is a weakness of the technique that can result in engraftment failure. To evaluate the efficacy of a new skin graft immobilization technique using multilayered polyurethane foam in vivo and in vitro. Twenty-six patients underwent a full-thickness skin graft. Multiple layers of a hydrocellular polyurethane foam dressing were used for skin graft immobilization. In addition, we created an in vitro skin graft model that allowed us to estimate immobilization pressure at the center and edges of skin grafts of various sizes. Overall mean graft survival was 88.9%. In the head and neck region (19 patients), mean graft survival was 93.6%. Based on the in vitro outcomes, this technique supplies effective pressure (skin graft. This multilayered polyurethane foam dressing is simple, safe, and effective for skin graft immobilization. © 2011 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

Retroperitoneal arteriovenous malformation extending through the inferior vena cava into the heart and causing inferior vena cava dissection

International Nuclear Information System (INIS)

Sung, Yon Mi; Choe, Yeon Hyeon; Park, Seung Woo; Park, Pyo Won; Sung, Chang Ohk

2005-01-01

We present a case of retroperitoneal arteriovenous malformation extending through the inferior vena cava into the heart, which was associated with dissection of the inferior vena cava in a 32-year-old female. Computed tomography and magnetic resonance imaging showed a double-lumen inferior vena cava and a rod-like solid component attached to a sac-like lesion in the right heart chambers. Digital subtraction angiography showed an arteriovenous malformation draining to the inner lumen of the inferior vena cava. (orig.)

Pial Arteriovenous Fistula Caused by Trauma: A Case Report

OpenAIRE

NOMURA, Seiji; ISHIKAWA, Osamu; TANAKA, Kentaro; OTANI, Ryohei; MIURA, Keisuke; MAEDA, Keiichiro

2015-01-01

We report an extremely rare case of pial arteriovenous fistula (AVF) caused by trauma. A 61-year-old man suffered from brain contusion by a traffic accident. He was neurologically normal on admission. However, his headache gradually worsened, and partial seizures occurred thereafter. He presented with general tonic seizure 7 days after the head injury. Magnetic resonance imaging demonstrated the exacerbation of brain edema and an abnormal vein near the contusion. Subsequent angiography showed...

Pretreatment Predictors of Adverse Radiation Effects After Radiosurgery for Arteriovenous Malformation

International Nuclear Information System (INIS)

Hayhurst, Caroline; Monsalves, Eric; Prooijen, Monique van; Cusimano, Michael; Tsao, May; Menard, Cynthia; Kulkarni, Abhaya V.; Schwartz, Michael; Zadeh, Gelareh

2012-01-01

Purpose: To identify vascular and dosimetric predictors of symptomatic T2 signal change and adverse radiation effects after radiosurgery for arteriovenous malformation, in order to define and validate preexisting risk models. Methods and Materials: A total of 125 patients with arteriovenous malformations (AVM) were treated at our institution between 2005 and 2009. Eighty-five patients have at least 12 months of clinical and radiological follow-up. Any new-onset headaches, new or worsening seizures, or neurological deficit were considered adverse events. Follow-up magnetic resonance images were assessed for new onset T2 signal change and the volume calculated. Pretreatment characteristics and dosimetric variables were analyzed to identify predictors of adverse radiation effects. Results: There were 19 children and 66 adults in the study cohort, with a mean age of 34 (range 6–74). Twenty-three (27%) patients suffered adverse radiation effects (ARE), 9 patients with permanent neurological deficit (10.6%). Of these, 5 developed fixed visual field deficits. Target volume and 12 Gy volume were the most significant predictors of adverse radiation effects on univariate analysis (p 3 , above which the rate of ARE increased dramatically. Multivariate analysis target volume and the absence of prior hemorrhage are the only significant predictors of ARE. The volume of T2 signal change correlates to ARE, but only target volume is predictive of a higher volume of T2 signal change. Conclusions: Target volume and the absence of prior hemorrhage is the most accurate predictor of adverse radiation effects and complications after radiosurgery for AVMs. A high percentage of permanent visual field defects in this series suggest the optic radiation is a critical radiosensitive structure.

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.

Effect of graft shape in lateral column lengthening on tarsal bone position and subtalar and talonavicular contact pressure in a cadaveric flatfoot model.

Science.gov (United States)

Campbell, Sean T; Reese, Keri A; Ross, Steven D; McGarry, Michelle H; Leba, Thu-Ba; Lee, Thay Q

2014-11-01

Lateral column lengthening (LCL) has been used for correction of flatfoot deformity. The purpose of this study was to determine the effect of LCL graft shape on tarsal bone position and talonavicular and subtalar joint pressure. A flatfoot model was created in 6 cadaveric specimens. Corrective LCL was performed using a rectangular graft or a trapezoidal graft with the broad surface oriented dorsally, laterally, or plantarly. Bony surface markers were digitized to calculate angular parameters used in the evaluation of flatfoot deformity. Contact pressure and area in the subtalar and talonavicular joints were also recorded. All measurements were carried out under multiple axial loads in the intact and flatfoot conditions, and following LCL with each graft shape. Flatfoot creation resulted in significant changes in arch collapse and forefoot abduction. LCL with a rectangular graft best corrected these parameters, while a laterally oriented trapezoidal graft provided some correction. Talonavicular contact pressure was unchanged after flatfoot creation, and was significantly less than intact after LCL. Subtalar contact pressure decreased in some conditions after flatfoot creation, and decreased further after LCL. LCL with a rectangular graft best restored tarsal bone orientation in a cadaveric flatfoot model. The decreases in talonavicular pressure likely represent redistribution of force from the medial to lateral foot. When performing LCL for flatfoot deformity, increased bone graft volume medially better restores tarsal bone position. One way of achieving this is through the use of a rectangular graft as opposed to a trapezoidal graft. © The Author(s) 2014.

Spinal cord arteriovenous shunts: from imaging to management

International Nuclear Information System (INIS)

Rodesch, G.; Lasjaunias, P.

2003-01-01

Spinal cord arteriovenous shunts (SCAVSs) are either fistulas or niduses that can be separated in four different groups according to their localization and relationship to the dura. Paraspinal AVSs are located outside the spine and are responsible for neurological symptoms because of cord compression by ertatic veins, venous congestion or arterial steal. Epidural shunts are located in the epidural space and drain in epidural veins with secondary intradural congestion. Dural shunts are embedded in the dura, produce a cord venous myelopathy after draining through veins that either pierce the dura far from a nerve root or accompany a nerve root. Intradural shunts affect the cord, the roots or the filum. Additionally, they can be classified according to their potential relationships with genetics, vascular biological features and angiogenesis into genetic hereditary lesions (hereditary hemorrhagic telangiectasia), genetic non-hereditary lesions (multiple lesions with metameric links) and single lesions (AVMs or micro AVFs). MRI and MRA are able to visualise SCAVS early after the onset of clinical symptoms. The type of shunt and its localization may remain difficult to be precise. Angiography remains the gold standard for analysis of the anatomical, morphological and architectural features necessary for therapeutic decisions in both paediatric and adult populations. In our series, embolisation is chosen in first intention whatever the type of shunt responsible for the clinical symptoms and glue is preferably used. In paraspinal, dural or epidural arteriovenous shunts, the goal of treatment should be complete closure of the shunt. A complete cure by embolization is rather easily achieved in paraspinal lesions. Failure of endovascular therapy in dural or epidural shunts must bring the patient to surgery. The prognosis of most intradural shunts seems better than previously thought, even after haemorrhage. In intradural spinal cord arteriovenous shunts, embolisation

Interventional therapy for priapism caused by arteriovenous fistula of penis: the nursing experience in two patients

International Nuclear Information System (INIS)

Peng Jinxia; Liu Ping; Jia Hongtao

2010-01-01

Objective: To discuss the perioperative nursing measures for interventional treatment of priapism caused by arteriovenous fistula of penis in order to reduce the operation-related complications and to promote rehabilitation. Methods: A series of nursing steps were carried out in 2 patients who suffered from priapism caused by arteriovenous fistula of penis and received interventional therapy. The nursing measures included preoperative psychological nursing,routine preoperative examinations, promotion of friendly relations between nurse and patient, preparation for the operation method, the preparation of skin, postoperative nursing of patient's position, observation of penis erection and vital signs, postoperative psychological nursing, and the health guidance at the time of discharge. Results: After the interventional therapy two patients were successfully cured at the time of discharge. No complications related to the operation occurred. Three months after the operation the erect function of the penis remained normal. Conclusion: The interventional therapy is a safe and reliable technique for priapism caused by arteriovenous fistula of penis. The proper and effective perioperative and postoperative nursing measures can surely improve the successful rate of interventional treatment as well as prevent the occurrence of complications. (authors)

Renal aneurysm and arteriovenous fistula

International Nuclear Information System (INIS)

Savastano, S.; Feltrin, G.P.; Miotto, D.; Chiesura-Corona, M.; Padua Univ.

1990-01-01

Embolization was performed in six patients with renal artery aneurysms (n=2) and arteriovenous fistulas (AVF) (n=5). The aneurysms were observed in one patient with fibromuscular dysplasia and in another with Ehlers-Danlos syndrome. All the AVFs were intraparenchymal and secondary to iatrogenic trauma. Elective embolization was performed in five patients with good clinical results at follow-up between 1 and 9 years. Because of rupture of the aneurysm emergency embolization was attempted without success in the patient with Ehlers-Danlos syndrome, and nephrectomy was carried out. A postembolization syndrome complicated three procedures in which Gelfoam and polyvinyl alcohol were used; in two of these cases unexpected reflux of the particulate material occurred, resulting in limited undesired ablation of the ipsilateral renal parenchyma. Embolization is the most reliable and effective treatment for intrarenal vascular abnormalities since it minimizes the parenchymal damage. (orig.)

Nogo-A Neutralization Improves Graft Function in a Rat Model of Parkinson’s Disease

Directory of Open Access Journals (Sweden)

Stefanie eSeiler

2016-04-01

Full Text Available Transplantation of fetal human ventral mesencephalic dopaminergic neurons into the striatum is a promising strategy to compensate for the characteristic dopamine deficit observed in Parkinson’s disease. This therapeutic approach, however, is currently limited by the high number of fetuses needed for transplantation and the poor survival and functional integration of grafted dopaminergic neurons into the host brain. Accumulating evidence indicates that contrasting inhibitory signals endowed in the central nervous system might support neuronal regeneration. Hence, in the present study we aimed at improving survival and integration of grafted cells in the host brain by neutralizing Nogo-A, one of the most potent neurite growth inhibitors in the central nervous system. For that purpose, ventral mesencephalic tissue cultures were transplanted into rats with a partial 6-hydroxydopamine lesion causing a hemi-Parkinson’s disease model and concomitantly treated for two weeks with intra-ventricular infusion of neutralizing anti-Nogo-A antibodies. Motor behavior using the cylinder test was assessed prior to and after transplantation as functional outcome. At the end of the experimental period the number of dopaminergic fibers growing into the host brain, the number of surviving dopaminergic neurons in the grafts as well as graft size was examined. We found that anti-Nogo-A antibody infusion significantly improved the asymmetrical forelimb use observed after lesions as compared to controls. Importantly, a significantly three-fold higher dopaminergic fiber outgrowth from the transplants was detected in the Nogo-A antibody treated group as compared to controls. Furthermore, Nogo-A neutralization showed a tendency for increased survival of dopaminergic neurons (by two fold in the grafts. No significant differences were observed for graft volume and the number of dopaminergic neurons co-expressing G-protein-coupled inward rectifier potassium channel subunit

Relevance of bone graft viability in a goat transverse process model

NARCIS (Netherlands)

Kruyt, Moyo C.; Delawi, Diyar; Habibovic, Pamela; Oner, F. Cumhur; van Blitterswijk, Clemens; Dhert, Wouter J.A.

2009-01-01

Little is known about the mechanism by which autologous bone grafts are so successful. The relevance of viable osteogenic cells, which is a prominent difference between autologous bone graft and conventional alternatives, is especially controversial. With the emergence of bone tissue engineering,

Selective digital venous hypertension: A rare complication of hemodialysis arteriovenous fistula

Energy Technology Data Exchange (ETDEWEB)

Swayne, L.C.; Manstein, C.; Somers, R.; Cope, C.

1983-04-01

We report and document angiographically a case of selective venous hypertension, masquerading as an infection, which involved the three middle digits of the right hand in a patient with an access arteriovenous (AV) fistula. This complication arose following hemodialysis and was resolved after resection of the right radial artery at the site of AV fistula and re-anastomosis.

Embolization of intracranial dural arteriovenous fistulas using PHIL liquid embolic agent in 26 patients

DEFF Research Database (Denmark)

Lamin, S.; Chew, H. S.; Chavda, S.

2017-01-01

BACKGROUND AND PURPOSE: The introduction of liquid embolic agents has revolutionized endovascular approach to cranial vascular malformations. The aim of the study was to retrospectively assess the efficacy and safety of Precipitating Hydrophobic Injectable Liquid (PHIL), a new nonadhesive liquid......: This was a retrospective multicenter study. Twenty-six consecutive patients with dural arteriovenous fistulas (de novo or previously treated) treated by injection of PHIL only or with PHIL in combination with other embolization products (such as Onyx or detachable coils) were included in the study. Recruitment started......, 3 were retreated with PHIL and 1 achieved angiographic cure. An adverse event was seen in 1 patient who developed worsening of preexisting ataxia due to acute thrombosis of the draining vein. CONCLUSIONS: PHIL appears to be safe and effective for endovascular treatment of cranial dural arteriovenous...

A sensitivity analysis of a personalized pulse wave propagation model for arteriovenous fistula surgery. Part A: Identification of most influential model parameters.

Science.gov (United States)

Huberts, W; de Jonge, C; van der Linden, W P M; Inda, M A; Tordoir, J H M; van de Vosse, F N; Bosboom, E M H

2013-06-01

Previously, a pulse wave propagation model was developed that has potential in supporting decision-making in arteriovenous fistula (AVF) surgery for hemodialysis. To adapt the wave propagation model to personalized conditions, patient-specific input parameters should be available. In clinics, the number of measurable input parameters is limited which results in sparse datasets. In addition, patient data are compromised with uncertainty. These uncertain and incomplete input datasets will result in model output uncertainties. By means of a sensitivity analysis the propagation of input uncertainties into output uncertainty can be studied which can give directions for input measurement improvement. In this study, a computational framework has been developed to perform such a sensitivity analysis with a variance-based method and Monte Carlo simulations. The framework was used to determine the influential parameters of our pulse wave propagation model applied to AVF surgery, with respect to parameter prioritization and parameter fixing. With this we were able to determine the model parameters that have the largest influence on the predicted mean brachial flow and systolic radial artery pressure after AVF surgery. Of all 73 parameters 51 could be fixed within their measurement uncertainty interval without significantly influencing the output, while 16 parameters importantly influence the output uncertainty. Measurement accuracy improvement should thus focus on these 16 influential parameters. The most rewarding are measurement improvements of the following parameters: the mean aortic flow, the aortic windkessel resistance, the parameters associated with the smallest arterial or venous diameters of the AVF in- and outflow tract and the radial artery windkessel compliance. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

Nanofat grafting under a split-thickness skin graft for problematic wound management.

Science.gov (United States)

Kemaloğlu, Cemal Alper

2016-01-01

Obesity and certain medical disorders make the reconstruction of skin defects challenging. Different kind of procedure can be used for these defect, besides, skin grafting is one of the most common and simplest procedure. Fat grafting and stem cells which are located in the adipose tissue have been commonly used in plastic surgery for regeneration and rejuvenation purposes. To decrease graft failure rate we performed nanofat grafting under an autologous split-thickness skin graft in our patient who had a problematic wound. The case of a 35-year-old female patient with a traumatic skin defect on her left anterior crural region is described herein. After subsequent flap reconstruction, the result was disappointing and the defect size was widened. The defect was treated with combined grafting (nanofat grafting under an autologous split-thickness skin graft). At the 6 months follow-up assessment after combined grafting, the integrity of the skin graft was good with excellent pliability. Combined grafting for problematic wounds seems to be a useful technique for cases requiring reconstruction. The potential existence of stem cells may be responsible for the successful result in our patient.

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

Susceptibility loci for sporadic brain arteriovenous malformation; a replication study and meta-analysis

NARCIS (Netherlands)

Kremer, P.H.; Koeleman, B.P.C.; Rinkel, G.J.; Diekstra, F.P.; Berg, L.H. van den; Veldink, J.H.; Klijn, C.J.M.

2016-01-01

BACKGROUND: Case-control studies have reported multiple genetic loci to be associated with sporadic brain arteriovenous malformations (AVMs) but most of these have not been replicated in independent populations. The aim of this study was to find additional evidence for these reported associations

Forcasting Acha production in Nigeria: A comparison of grafted ...

African Journals Online (AJOL)

A grafted model (Quadratic-Quadratic-Linear) was estimated to forecast Acha output for periods outside the sample. The estimated structural parameters gave an R squared values of 0.81 and 0.99 for the linear and grafted respectively. Forecast were generated to evaluate the predictive performance of the estimated models ...

Cerebral arterio-venous malformations at Edgardo Rebagliati Martins Nacional Hospital

OpenAIRE

Rabanal, Jorge

2014-01-01

A review of 50 cases with cerebral arterio.venous malformations (AVM) treated since Junly 1988 through December 1992 in the Neurosurgery Service from Edgardo Rebagliati Martins National Hospital was done. Clinical records, surgical techniques and pre- and post-operative studies were evaluted by retrospective analysis. The more important results were the frecuency of presentations in male patients from the coast, the clinical onset with intracraneal hemorrhage, the operative technique of drain...

Primary contraction of skin grafts: a porcine preliminary study

Directory of Open Access Journals (Sweden)

Alexander Bogdanov Berezovsky

2015-03-01

Full Text Available Aim: Skin grafting is a common clinical practice for plastic surgeons, yet primary contraction of these grafts is a neglected topic. This study was designed to investigate primary contraction and introduce the shape of skin graft as a possible factor that modifies primary contraction behavior, using porcine models. Methods: In the first series, full-thickness skin grafts (FTSGs and split-thickness skin grafts (STSGs were compared. In a second series, how the shape of the skin graft affected the degree of contraction was examined. Results: The mean percentage of FTSG shrinkage was 12.04%, and the median was 12.18%. The mean percentage of STSG shrinkage was 6.87%, and the median was 5%. Circle-shaped and square-shaped FTSGs showed mean/median graft shrinkage of 5.83%/6.93% and 4.15%/3.75%, respectively. In STSGs, the circle-shaped and square-shaped grafts had mean/median graft shrinkage of 1.07%/0% and 0.31%/0%, respectively. Conclusion: Our preliminary report revealed an expected greater shrinkage of FTSGs compared with STSGs. Furthermore, in a limited number of specimens, the shape of the skin graft seemed to affect the primary contraction of the STSGs.

Peripheral arteriovenous fistula as vascular access for long-term chemotherapy.

Science.gov (United States)

Kovalyov, Oleksiy O; Kostyuk, Oleksandr G; Tkachuk, Tetyana V

To provide long-term vascular access in clinical oncology peripheral forearm veins (up to 95% of patients in Ukraine), central venous access and "complete implanted vascular systems" are used most often. Many oncology patients have contraindications to catheterization of superior vena cava. Besides, exploitation of central veins is associated with potential technical and infectious complications. The aim - to study short-term and long-term results of arteriovenous fistula exploitation as vascular access for continuous anticancer therapy. Peripheral venous bed status in 41 oncology patients taking long-term chemotherapy treatment is analyzed in the article. Doppler sonography, morphologic and immune histochemical analyses were used in the study. Doppler sonography found qualitative and quantitative changes in forearm veins at different time periods after initiation of chemotherapy in the majority of patients. The major morphologic manifestations of venous wall damage were chemical phlebitis, local or extended hardening of venous wall, venous thrombosis and extravasations with necrosis and subsequent paravasal tissue sclerosis. Alternative vascular access created in 12 patients completely met the adequacy criteria (safety, multiple use, longevity, realization of the designed therapy program). The conclusion was made about inapplicability of forearm veins for long-term administration of cytostatic agents. If it is impossible to use central veins, arteriovenous fistula can become an alternative vascular access.

Similar degree of intimal hyperplasia in surgically detected stenotic and nonstenotic arteriovenous fistula segments: a preliminary report.

Science.gov (United States)

Duque, Juan C; Tabbara, Marwan; Martinez, Laisel; Paez, Angela; Selman, Guillermo; Salman, Loay H; Velazquez, Omaida C; Vazquez-Padron, Roberto I

2018-04-01

Intimal hyperplasia has been historically associated with improper venous remodeling and stenosis after creation of an arteriovenous fistula. Recently, however, we showed that intimal hyperplasia by itself does not explain the failure of maturation of 2-stage arteriovenous fistulas. We seek to evaluate whether intimal hyperplasia plays a role in the development of focal stenosis of an arteriovenous fistula. This study compares intimal hyperplasia lesions in stenotic and nearby nonstenotic segments collected from the same arteriovenous fistula. Focal areas of stenosis were detected in the operating room in patients (n= 14) undergoing the second-stage vein transposition procedure. The entire vein was inspected, and areas of stenosis were visually located with the aid of manual palpation and hemodynamic changes in the vein peripheral and central to the narrowing. Stenotic and nonstenotic segments were documented by photography before tissue collection (14 tissue pairs). Intimal area and thickness, intima-media thickness, and intima to media area ratio were measured in hematoxylin and eosin stained cross-sections followed by pairwise statistical comparisons. The intimal area in stenotic and nonstenotic segments ranged from 1.25 to 11.61 mm 2 and 1.29 to 5.81 mm 2 , respectively. There was no significant difference between these 2 groups (P=.26). Maximal intimal thickness (P=.22), maximal intima-media thickness (P=.13), and intima to media area ratio (P=.73) were also similar between both types of segments. This preliminary study indicates that postoperative intimal hyperplasia by itself is not associated with the development of focal venous stenosis in 2-stage fistulas. Copyright © 2017 Elsevier Inc. All rights reserved.

Pressure measurements in arterial feeders of brain arteriovenous malformations before and after endovascular embolization

International Nuclear Information System (INIS)

Henkes, H.; Gotwald, T.F.; Brew, S.; Kaemmerer, F.; Miloslavski, E.; Kuehne, D.

2004-01-01

Arteriovenous malformations (AVMs) are composed of abnormal arterial and venous vessels in the brain causing arteriovenous shunts of arterialized blood directly from pial arteries to draining veins. The hemodynamics of these lesions is not well-understood. Changes in blood flow and pressure are probably related to the natural history of AVMs and may also play a major role in AVM treatment. In this study intra-arterial pressure was measured in feeding arteries of AVMs using a microcatheter that had been placed for subsequent embolization treatment (201 measurements were performed in 95 patients before and after the embolization procedure). Results show a direct relationship between pressure changes and degree of embolization. Since pressure changes during the embolization procedure are relatively small, it seems unlikely that these changes are the direct cause of rupture and periprocedural bleedings. (orig.)

Four-dimensional computed tomography angiographic evaluation of cranial dural arteriovenous fistula before and after embolization.

Science.gov (United States)

Tian, Bing; Xu, Bing; Lu, Jianping; Liu, Qi; Wang, Li; Wang, Minjie

2015-06-01

This study aimed to evaluate the usefulness of four-dimensional CTA before and after embolization treatment with ONYX-18 in eleven patients with cranial dural arteriovenous fistulas, and to compare the results with those of the reference standard DSA. Eleven patients with cranial dural arteriovenous fistulas detected on DSA underwent transarterial embolization with ONYX-18. Four-dimensional CTA was performed an average of 2 days before and 4 days after DSA. Four-dimensional CTA and DSA images were reviewed by two neuroradiologists for identification of feeding arteries and drainage veins and for determining treatment effects. Interobserver and intermodality agreement between four-dimensional CTA and DSA were assessed. Forty-two feeding arteries were identified for 14 fistulas in the 11 patients. Of these, 36 (85.71%) were detected on four-dimensional CTA. After transarterial embolization, one patient got partly embolized, and the fistulas in the remaining 10 patients were completely occluded. The interobserver agreement for four-dimensional CTA and intermodality agreement between four-dimensional CTA and DSA were excellent (κ=1) for shunt location, identification of drainage veins, and fistula occlusion after treatment. Four-dimensional CTA images are highly accurate when compared with DSA images both before and after transarterial embolization treatment. Four-dimensional CTA can be used for diagnosis as well as follow-up of cranial dural arteriovenous fistulas in clinical settings. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

False traumatic aneurysms and arteriovenous fistulas: retrospective analysis.

Science.gov (United States)

Davidovic, Lazar B; Banzić, Igor; Rich, Norman; Dragaš, Marko; Cvetkovic, Slobodan D; Dimic, Andrija

2011-06-01

The purpose of this study was to analyze the incidence, clinical presentation, diagnosis, and treatment of false traumatic aneurysms and arteriovenous fistulas as well as the outcomes of the patients. A retrospective, 16-year survey has been conducted regarding the cases of patients who underwent surgery for false traumatic aneurysms (FTA) of arteries and traumatic arteriovenous fistulas (TAVF). Patients with iatrogenic AV fistulas and iatrogenic false aneurysms were excluded from the study. There were 36 patients with TAVF and 47 with FTA. In all, 73 (87.95%) were male, and 10 (12.05%) were female, with an average age of 36.93 years (13-82 years). In 25 (29.76%) cases TAVF and FTA appeared combat-related, and 59 (70.24%) were in noncombatants. The average of all intervals between the injury and surgery was 919. 8 days (1 day to 41 years) for FTA and 396.6 days (1 day to 9 years) for TAVF. Most of the patients in both groups were surgically treated during the first 30 days after injury. One patient died on the fourth postoperative day. There were two early complications. The early patency rate was 83.34%, and limb salvage was 100%. There were no recurrent AV fistulas that required additional operations. Because of their history of severe complications, FTA and TAV fistulas require prompt treatment. The treatment is simpler if there is only a short interval between the injury and the operation. Surgical endovascular repair is mostly indicated.

Bone Graft Alternatives

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... 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 ...

Arteriovenous extracorporeal lung assist allows for maximization of oscillatory frequencies: a large-animal model of respiratory distress

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Kranke Peter

2008-11-01

Full Text Available Abstract Background Although the minimization of the applied tidal volume (VT during high-frequency oscillatory ventilation (HFOV reduces the risk of alveolar shear stress, it can also result in insufficient CO2-elimination with severe respiratory acidosis. We hypothesized that in a model of acute respiratory distress (ARDS the application of high oscillatory frequencies requires the combination of HFOV with arteriovenous extracorporeal lung assist (av-ECLA in order to maintain or reestablish normocapnia. Methods After induction of ARDS in eight female pigs (56.5 ± 4.4 kg, a recruitment manoeuvre was performed and intratracheal mean airway pressure (mPaw was adjusted 3 cmH2O above the lower inflection point (Plow of the pressure-volume curve. All animals were ventilated with oscillatory frequencies ranging from 3–15 Hz. The pressure amplitude was fixed at 60 cmH2O. At each frequency gas exchange and hemodynamic measurements were obtained with a clamped and de-clamped av-ECLA. Whenever the av-ECLA was de-clamped, the oxygen sweep gas flow through the membrane lung was adjusted aiming at normocapnia. Results Lung recruitment and adjustment of the mPaw above Plow resulted in a significant improvement of oxygenation (p Conclusion In this animal model of ARDS, maximization of oscillatory frequencies with subsequent minimization of VT leads to hypercapnia that can only be reversed by adding av-ECLA. When combined with a recruitment strategy, these high frequencies do not impair oxygenation

LETTER TO THE EDITOR: Arterio-venous flow between monochorionic twins determined during intra-uterine transfusion. Nonlinear decay of adult red blood cells

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van Gemert, Martin J. C.; Pasman, Suzanne A.; van den Wijngaard, Jeroen P. H. M.; Lopriore, Enrico; Vandenbussche, Frank P. H. A.

2008-07-01

Recently, we derived equations relating the flow of adult red blood cells through a placental arterio-venous anastomosis with intra-uterine and post-natal measured adult hemoglobin concentrations. In this letter, we re-derived the equations, now including a more realistic nonlinear decay of adult red blood cells, and re-evaluated the measurement accuracy of the arterio-venous flow and the lifetime of the red blood cells.

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

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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

Effect of Grafting Method, Graft Cover and Foliar Spray of some Mineral Elements on Persian Walnut Graft-take and Winter Survival Rate

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Reza Rezaee

2017-09-01

Full Text Available Introduction: Persian walnut (Juglans regia L. is an important nut crop in Iran and many parts of the world. One of the major challenges of growing walnut is planting of non-grafted walnut trees in orchards, which leads to the reduction of yield, quality and productivity of walnut orchards. Compared to the other fruit trees, walnut grafting is difficult and even newly grafted walnut seedlings are vulnerable to fall or winter frost chilling, so that most of the seedlings are lost after subjecting to the cold winter. There are a few studies reporting successful grafting in outdoor conditions, however, final grafting take after winter has been usually ignored. Hence, increased walnut grafting success and improved tree growth after grafting through foliar nutrient application may lead to increased tolerance of chilling. Therefore, main goals of this research were to investigate the effect of some graft covers and role of foliar spray of calcium, boron and zinc on the reduction of frost damage in newly grafted seedlings under outdoor conditions. Materials and methods: This research was conducted at agricultural research station, Khoy city, west Azerbaijan province, during 2012-2014. In the first experiment, three methods of grafting including cleft, bark and V-shaped, and two kinds of graft covers including moist sawdust and superabsorbent plus cotton wool were investigated in terms of grafting success and quality of seedlings. In the second experiment, effect of the three above-mentioned grafting methods and two levels of foliar spray including sequential spray of Ca (4 ppm, B and Zn (2% (3 times during growth season and control (no spray were studied in terms of frost damage. The experiments conducted in factorial based on randomized complete block design with 10 trees in each plot. Data were collected 45 days after grafting take, final grafting take after one winter, subsequent scion growth length and diameter and concentration of Ca, B and Zn in

Traumatic subclavian arteriovenous fistula in a young adult

International Nuclear Information System (INIS)

Nazario Dolz, Ana Maria; Ibannez Casero, Marlene; Rodriguez Fernandez, Zenen; Pichin Quesada, Alexis; Lopez Martin, Jose Carlos

2011-01-01

The case report of a 23 year-old patient who was admitted to the General Surgery Service of 'Saturnino Lora Torres' Provincial Teaching Clinical Surgical Hospital in Santiago de Cuba with the diagnosis of traumatic pneumothorax is described, as consequence of stab wounds in the right anterior and superior region of the thorax; but then, after 48 hours, a right subclavian arteriovenous fistula, which was proven by means of x ray was diagnosed. The postoperative clinical course was favorable and the patient was discharged after 11 days, completely asymptomatic. His working activities began 2 months later.(author)

Suction blister grafting - Modifications for easy harvesting and grafting

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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.

Massive Left-sided Congestive Colitis Due to Idiopathic Inferior Mesenteric Arteriovenous Malformation

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Laura Martí Gelonch

2017-01-01

Full Text Available Arteriovenous malformations (AVM of the inferior mesenteric artery are rare. They may be primary (congenital or idiopathic or secondary (acquired after trauma or of iatrogenic origin. Of the abdominal AVM, the inferior mesenteric trunk is the least commonly involved. Most reported cases are of iatrogenic origin, resulting from colon surgery. Only 17 cases have been described and published in the literature. The objective of this work is to make known a case treated in our center. We present a case of 73-year old male, who came to the emergency service with symptoms of abdominal distension, pain lasting 48 hours along with months of diarrhoea. CT scan and an abdominal CT angiography showed a massive left-sided congestive colitis due to idiopathic inferior mesenteric arteriovenous malformation. In our case, the decision was to carry out the treatment in two stages. Embolisation was performed in the first stage in order to decrease the blood flow and the risk of intraoperative bleeding, followed by resective surgery of the affected colon.

Biofabrication and testing of a fully cellular nerve graft

International Nuclear Information System (INIS)

Owens, Christopher M; Marga, Francoise; Forgacs, Gabor; Heesch, Cheryl M

2013-01-01

Rupture of a nerve is a debilitating injury with devastating consequences for the individual's quality of life. The gold standard of repair is the use of an autologous graft to bridge the severed nerve ends. Such repair however involves risks due to secondary surgery at the donor site and may result in morbidity and infection. Thus the clinical approach to repair often involves non-cellular solutions, grafts composed of synthetic or natural materials. Here we report on a novel approach to biofabricate fully biological grafts composed exclusively of cells and cell secreted material. To reproducibly and reliably build such grafts of composite geometry we use bioprinting. We test our grafts in a rat sciatic nerve injury model for both motor and sensory function. In particular we compare the regenerative capacity of the biofabricated grafts with that of autologous grafts and grafts made of hollow collagen tubes by measuring the compound action potential (for motor function) and the change in mean arterial blood pressure as consequence of electrically eliciting the somatic pressor reflex. Our results provide evidence that bioprinting is a promising approach to nerve graft fabrication and as a consequence to nerve regeneration. (paper)

A Case Report of Onyx Pulmonary Arterial Embolism Contributing to Hypoxemia During Awake Craniotomy for Arteriovenous Malformation Resection.

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Tolly, Brian T; Kosky, Jenna L; Koht, Antoun; Hemmer, Laura B

2017-02-15

A healthy 26-year-old man with cerebral arteriovenous malformation underwent staged endovascular embolization with Onyx followed by awake craniotomy for resection. The perioperative course was complicated by tachycardia and severe intraoperative hypoxemia requiring significant oxygen supplementation. Postoperative chest computed tomography (CT) revealed hyperattenuating Onyx embolization material within the pulmonary vasculature, and an electrocardiogram indicated possible right heart strain, supporting clinically significant embolism. With awake arteriovenous malformation resection following adjunctive Onyx embolization becoming increasingly employed for lesions involving the eloquent cortex, anesthesiologists need to be aware of pulmonary migration of Onyx material as a potential contributor to significant perioperative hypoxemia.

Contemporary Management of Pulmonary Arteriovenous Malformations.

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Rauh, Nicholas; Gurley, John; Saha, Sibu

2017-12-01

Pulmonary arteriovenous malformations (PAVMs) are atypical vascular structures involving a direct connection between the pulmonary arterial and venous circulations. While PAVMs are a relatively uncommon disorder, unmanaged cases are at risk for the development of serious complications including embolization and infection. Since their first description in 1897, PAVMs have been identified and treated in a variety of ways. Advancements in diagnostic methods and operative techniques have allowed for more effective treatment of the disease. Most recently, the use of vascular plug transcatheter embolization has been described as an effective therapeutic procedure in the management of PAVMs. In this report, we present our experience with nine cases of PAVMs treated at the University of Kentucky, including special consideration of an exemplary case that illustrates the typical course of treatment for the disease.

Computational fluid dynamic evaluation of the side-to-side anastomosis for arteriovenous fistula.

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Hull, Jeffrey E; Balakin, Boris V; Kellerman, Brad M; Wrolstad, David K

2013-07-01

The goal of this research was to compare side-to-side (STS) and end-to-side (ETS) anastomoses in a computer model of the arteriovenous fistula with computational fluid dynamic analysis. A matrix of 17 computer arteriovenous fistula models (SolidWorks, Dassault Systèmes, France) of artery-vein pairs (3-mm-diameter artery + 3-mm-diameter vein and 4-mm-diameter artery +6-mm-diameter vein elliptical anastomoses) in STS, 45° ETS, and 90° ETS configurations with cross-sectional areas (CSAs) of 3.5 to 18.8 mm(2) were evaluated with computational fluid dynamic software (STAR-CCM+; CD-adapco, Melville, NY) in simulations at defined flow rates from 600 to 1200 mL/min and mean arterial pressures of 50 to 140 mm Hg. Models and configurations were evaluated for pressure drop across the anastomosis, arterial inflow, venous outflow, arterial outflow, velocity vector, and wall shear stress (WSS) profile. Pressure drop across the anastomosis was inversely proportional to anastomotic CSA and to venous outflow and was proportional to arterial inflow. Pressure drop was greater in 3 + 3 models than in 4 + 6 STS models; 90° ETS configurations had the lowest pressure drops and were nearly identical, whereas 45° ETS configurations had the highest pressure drops. Venous outflow in the 4 + 6 model in STS configurations, evaluated at 100 mm Hg arterial inflow pressure, was 390, 592, 610, and 886 mL/min in anastomotic CSAs of 3.5, 5.3, 7.1, and 18.8 mm(2), respectively, and was similar in 90° ETS (609 and 908 mL/min) and lower in 45° ETS (534 and 562 mL/min) configurations at CSAs of 5.3 and 18.8 mm(2). The mean increase in venous outflow was 69 mL/min (range, -59 to 134) between 3 + 3 and 4 + 6 models at 100 mm Hg arterial inflow. The most uniform WSS profile occurs in STS anastomoses followed by 45° ETS and then 90° ETS anastomoses. The STS and 90° ETS anastomoses have high venous outflow and a tendency toward reversed arterial outflow. The 45° ETS anastomosis has reduced venous

Delayed grafting for banked skin graft in lymph node flap transfer.

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Ciudad, Pedro; Date, Shivprasad; Orfaniotis, Georgios; Dower, Rory; Nicoli, Fabio; Maruccia, Michele; Lin, Shu-Ping; Chuang, Chu-Yi; Chuang, Tsan-Yu; Wang, Gou-Jen; Chen, Hung-Chi

2017-02-01

Over the last decade, lymph node flap (LNF) transfer has turned out to be an effective method in the management of lymphoedema of extremities. Most of the time, the pockets created for LNF cannot be closed primarily and need to be resurfaced with split thickness skin grafts. Partial graft loss was frequently noted in these cases. The need to prevent graft loss on these iatrogenic wounds made us explore the possibility of attempting delayed skin grafting. We have herein reported our experience with delayed grafting with autologous banked split skin grafts in cases of LNF transfer for lymphoedema of the extremities. Ten patients with International Society of Lymphology stage II-III lymphoedema of upper or lower extremity were included in this study over an 8-month period. All patients were thoroughly evaluated and subjected to lymph node flap transfer. The split skin graft was harvested and banked at the donor site, avoiding immediate resurfacing over the flap. The same was carried out in an aseptic manner as a bedside procedure after confirming flap viability and allowing flap swelling to subside. Patients were followed up to evaluate long-term outcomes. Flap survival was 100%. Successful delayed skin grafting was done between the 4th and 6th post-operative day as a bedside procedure under local anaesthesia. The split thickness skin grafts (STSG) takes more than 97%. One patient needed additional medications during the bedside procedure. All patients had minimal post-operative pain and skin graft requirement. The patients were also reported to be satisfied with the final aesthetic results. There were no complications related to either the skin grafts or donor sites during the entire period of follow-up. Delayed split skin grafting is a reliable method of resurfacing lymph node flaps and has been shown to reduce the possibility of flap complications as well as the operative time and costs. © 2016 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

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...

Intracranial dural arterio-venous fistula presenting with progressive myelopathy.

LENUS (Irish Health Repository)

Ogbonnaya, Ebere Sunny

2011-01-01

Spinal dural arterio-venous fistula (DAVF) is rare and usually involves the thoracic segments. The classical presentation is a slowly progressive ataxia. Clinical presentation of intracranial DAVF depends on the site of the DAVF, as well as the vessels involved. Patients may present with pulsatile tinnitus, occipital bruit, headache, dementia, visual impairment as well as neurological deterioration distant from the DAVF as a result of venous hypertension and cortical haemorrhage. The authors present a rare case of progressive myelopathy secondary to an intracranial DAVF.

Stereotactic radiosurgery for deep intracranial arteriovenous malformations, part 1: Brainstem arteriovenous malformations.

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Cohen-Inbar, Or; Ding, Dale; Chen, Ching-Jen; Sheehan, Jason P

2016-02-01

The management of brainstem arteriovenous malformations (AVM) are one of the greatest challenges encountered by neurosurgeons. Brainstem AVM have a higher risk of hemorrhage compared to AVM in other locations, and rupture of these lesions commonly results in devastating neurological morbidity and mortality. The potential morbidity associated with currently available treatment modalities further compounds the complexity of decision making for affected patients. Stereotactic radiosurgery (SRS) has an important role in the management of brainstem AVM. SRS offers acceptable obliteration rates with lower risks of hemorrhage occurring during the latency period. Complex nidal architecture requires a multi-disciplinary treatment approach. Nidi partly involving subpial/epipial regions of the dorsal midbrain or cerebellopontine angle should be considered for a combination of endovascular embolization, micro-surgical resection and SRS. Considering the fact that incompletely obliterated lesions (even when reduced in size) could still cause lethal hemorrhages, additional treatment, including repeat SRS and surgical resection should be considered when complete obliteration is not achieved by first SRS. Patients with brainstem AVM require continued clinical and radiological observation and follow-up after SRS, well after angiographic obliteration has been confirmed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Photoacoustic detection of neovascularities in skin graft

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Yamazaki, Mutsuo; Sato, Shunichi; Saitoh, Daizo; Ishihara, Miya; Okada, Yoshiaki; Ashida, Hiroshi; Obara, Minoru

2005-04-01

We previously proposed a new method for monitoring adhesion of skin graft by measuring photoacoustic (PA) signal originated from the neovascularities. In this study, immunohistochemical staining (IHC) with CD31 antibody was performed for grafted skin tissue to observe neovascularity, and the results were compared with PA signals. We also used a laser Doppler imaging (LDI) to observe blood flow in the grafted skin, and sensitivity of PA measurement and that of LDI were compared. In rat autograft models, PA signals were measured for the grafted skin at postgrafting times of 0-48 h. At 6 h postgrafting, PA signal was observed in the skin depth region of 500-600 mm, while the results of IHC showed that angiogenesis occurred at the depth of about 600 mm. Depths at which PA signal and angiogenesis were observed decreased with postgrafting time. These indicate that the PA signal observed at 6 h postgrafting originated from the neovascularities in the skin graft. Results of LDI showed no blood-originated signal before 48 h postgrafting. These findings suggest that PA measurement is effective in monitoring the adhesion of skin graft in early stage after transplantation.

Embolization of Uterine Arteriovenous Malformations Associated with Cyanotic Congenital Heart Disease

International Nuclear Information System (INIS)

Wijesekera, N. T.; Padley, S. P.; Kazmi, F.; Davies, C. L.; McCall, J. M.

2009-01-01

Uterine arteriovenous malformation (AVM) is a rare cause of vaginal bleeding and miscarriage. We report two cases of uterine AVMs in patients with a history of complex congenital heart disease, an association that has not been previously described. Both patients were treated by selective uterine artery embolization, a minimally invasive therapy that has revolutionized the management of uterine AVMs, thus offering an alternative to conventional hysterectomy.

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

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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.

Progressive subcortical calcifications secondary to venous hypertension in an intracranial dural arteriovenous fistula.

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Pascoe, Heather M; Lui, Elaine H; Mitchell, Peter; Gaillard, Frank

2017-05-01

Intracranial dural arteriovenous fistulas (dAVF) are acquired lesions, with the most commonly reported findings on CT haemorrhage or focal oedema. We describe a case of progressive subcortical calcification on CT secondary to venous hypertension from a high grade dAVF. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Establishment of a murine graft-versus-myeloma model using allogeneic stem cell transplantation.

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Marilène Binsfeld

Full Text Available Multiple myeloma (MM is a malignant plasma cell disorder with poor long-term survival and high recurrence rates. Despite evidence of graft-versus-myeloma (GvM effects, the use of allogeneic hematopoietic stem cell transplantation (allo-SCT remains controversial in MM. In the current study, we investigated the anti-myeloma effects of allo-SCT from B10.D2 mice into MHC-matched myeloma-bearing Balb/cJ mice, with concomitant development of chronic graft-versus-host disease (GvHD.Balb/cJ mice were injected intravenously with luciferase-transfected MOPC315.BM cells, and received an allogeneic (B10.D2 donor or autologous (Balb/cJ donor transplant 30 days later. We observed a GvM effect in 94% of the allogeneic transplanted mice, as the luciferase signal completely disappeared after transplantation, whereas all the autologous transplanted mice showed myeloma progression. Lower serum paraprotein levels and lower myeloma infiltration in bone marrow and spleen in the allogeneic setting confirmed the observed GvM effect. In addition, the treated mice also displayed chronic GvHD symptoms. In vivo and in vitro data suggested the involvement of effector memory CD4 and CD8 T cells associated with the GvM response. The essential role of CD8 T cells was demonstrated in vivo where CD8 T-cell depletion of the graft resulted in reduced GvM effects. Finally, TCR Vβ spectratyping analysis identified Vβ families within CD4 and CD8 T cells, which were associated with both GvM effects and GvHD, whereas other Vβ families within CD4 T cells were associated exclusively with either GvM or GvHD responses.We successfully established an immunocompetent murine model of graft-versus-myeloma. This is the first murine GvM model using immunocompetent mice that develop MM which closely resembles human MM disease and that are treated after disease establishment with an allo-SCT. Importantly, using TCR Vβ spectratyping, we also demonstrated the presence of GvM unique responses

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

The MDCT and MRI Findings of a Pancreatic Arteriovenous Malformation Combined with Isolated Dissection of the Superior Mesenteric Artery: A Case Report

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Kim, Yong Soo; Jeong, Woo Kyoung [Hanyang University Guri Hospital, Seoul (Korea, Republic of); Kim, Jin Oo [Naval Pohang Hospital, Pohang (Korea, Republic of); Oh, Ji Young; Song, Soon Young [Hanyang University Medical College, Seoul (Korea, Republic of)

2010-03-15

Pancreatic arteriovenous malformation and isolated spontaneous dissection of the superior mesenteric artery are both rare maladies, and now they can be easily diagnosed due to the development of such noninvasive modalities as multi-detector computed tomography and magnetic resonance imaging. We report here on the multi-detector computed tomography and magnetic resonance imaging findings of a rare case of pancreatic arteriovenous malformation combined with isolated dissection of the superior mesenteric artery.

The MDCT and MRI Findings of a Pancreatic Arteriovenous Malformation Combined with Isolated Dissection of the Superior Mesenteric Artery: A Case Report

International Nuclear Information System (INIS)

Kim, Yong Soo; Jeong, Woo Kyoung; Kim, Jin Oo; Oh, Ji Young; Song, Soon Young

2010-01-01

Pancreatic arteriovenous malformation and isolated spontaneous dissection of the superior mesenteric artery are both rare maladies, and now they can be easily diagnosed due to the development of such noninvasive modalities as multi-detector computed tomography and magnetic resonance imaging. We report here on the multi-detector computed tomography and magnetic resonance imaging findings of a rare case of pancreatic arteriovenous malformation combined with isolated dissection of the superior mesenteric artery

Comparison of Axillary Loop and Straight Grafts Patency and Their Complications for Hemodialylis Access

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J KHoshnevis

2011-08-01

Full Text Available Introduction & Objective: Dialysis vascular access complications are important causes of morbidity in chronic hemodialysis patients. The aim of the present study was a comparison of auxillary loop and atraight grafts patency and its complications for hemodialysis access. Materials & Methods: In this cohort study conducted at Shahid Beheshti Medical University, 58 patients who underwent placement of loop or straight access grafts were included in the study. Demographics, primary and secondary patency rates and complications like thrombosis, infection, bleeding, steal syndrome and other complications were compared in these two groups. The collected data was analyzed by the SPSS statistical software using the chi-square test, t-test, and logistic regression. Results: Thrombosis rates were 51.1% and 53.8% in straight and loop groups respectively (P=0.862, steal syndrome rates were 2.2% and 7.7% in straight and loop groups respectively (P=0.341, psudoanevrism were 11.1% and 23.1% in straight and loop groups respectively (P=0.270, bleeding rates were 4.4% and 0% in straight and loop groups respectively (P=0.439, infection rate were 8.9% and 7.7% in straight and loop groups respectively (P=0.892, and primary patency rate after 1 month were 88.9% and 92.3% respectively (P=0.721, and primary patency rate after 24 month were 31% and 55.5% respectively (P=0.058. Secondary patency rate after 3 month were 75.6% and 92.3% respectively (P=0.189, and secondary patency rate after 24 month were 37.9% and 66.7% respectively (P=0.044. Conclusion: PTFE vascular graft seems to be an appropriate vascular access and is a promising alternative when upper extremity arteriovenous fistulas cannot be constructed. Additionally, there was no significant different between two groups for complications and early patency, but late patency was better in loop group. More study is necessary for final judgment.

Application of grafted polynomial function in forecasting cotton ...

African Journals Online (AJOL)

A study was conducted to forecast cotton production trend with the application of a grafted polynomial function in Nigeria from 1985 through 2013. Grafted models are used in econometrics to embark on economic analysis involving time series. In economic time series, the paucity of data and their availability has always ...

Neuro-peptide treatment with Cerebrolysin improves the survival of neural stem cell grafts in an APP transgenic model of Alzheimer disease

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Edward Rockenstein

2015-07-01

Full Text Available Neural stem cells (NSCs have been considered as potential therapy in Alzheimer's disease (AD but their use is hampered by the poor survival of grafted cells. Supply of neurotrophic factors to the grafted cells has been proposed as a way to augment survival of the stem cells. In this context, we investigated the utility of Cerebrolysin (CBL, a peptidergic mixture with neurotrophic-like properties, as an adjunct to stem cell therapy in an APP transgenic (tg model of AD. We grafted murine NSCs into the hippocampus of non-tg and APP tg that were treated systemically with CBL and analyzed after 1, 3, 6 and 9 months post grafting. Compared to vehicle-treated non-tg mice, in the vehicle-treated APP tg mice there was considerable reduction in the survival of the grafted NSCs. Whereas, CBL treatment enhanced the survival of NSCs in both non-tg and APP tg with the majority of the surviving NSCs remaining as neuroblasts. The NSCs of the CBL treated mice displayed reduced numbers of caspase-3 and TUNEL positive cells and increased brain derived neurotrophic factor (BDNF and furin immunoreactivity. These results suggest that CBL might protect grafted NSCs and as such be a potential adjuvant therapy when combined with grafting.

The use of arteriovenous anastomosis for venous drainage during Tamai zone I fingertip replantation.

Science.gov (United States)

Wu, Fei; Shen, Xiaofang; Eberlin, Kyle R; Sun, Zhibo; Zhou, Xiao; Xue, Mingyu

2018-03-27

The purpose of this study was to evaluate outcomes for patients sustaining a distal fingertip amputation who underwent replantation witharteriovenous anastomosis for venous drainage over a one year period at our institution. This technique has been utilized when insufficient veins are identified in the amputated part for standard veno-venous anastomosis. A retrospective study was performed on patients presenting from 2013 to 2014. Guillotine, crush, and avulsion/degloving injuries were included if they underwent fingertip (Tamai Zone I) replantation with arterial anastomosis for vascular inflow and arteriovenous anastomosis for venous drainage. The cases were further classified as Ishikawa subzone I and subzone II. Arteriovenous anastomosis for venous drainage during replantation was used in 45 digits in 35 patients. 41 of the 45 digits underwent successful replantation using this technique (91%). The mean active ROM in the DIP joint of the fingers and in the IP joint of thumbs was 65° and 57°, respectively. Sensory evaluation demonstrated a mean of 6.9 mm s2PD in digits where the digital nerves could be repaired. 11 replanted digits without nerve repair regained some sensory recovery with a mean of 9.6 mm s2PD. 91% of patients were highly satisfied with the appearance of the replanted digits based on Tamai criteria. Arteriovenous anastomosis for venous outflow should be considered during zone I fingertip replantation if sufficient veins are not identified in the amputated part. This technique may allow for more routine and successful distal replantation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Treatment of arteriovenous malformations with stereotactic radiosurgery employing both magnetic resonance angiography and standard angiography as a database

International Nuclear Information System (INIS)

Petereit, D.; Mehta, M.; Turski, P.; Levin, A.; Strother, C.; Mistretta, C.; Mackie, R.; Gehring, M.; Kubsad, S.; Kinsella, T.

1993-01-01

Twenty-one arteriovenous malformations were prospectively evaluated using magnetic resonance angiography, compare it to stereotactic angiography, employ magnetic resonance angiography in follow-up, and semiquanitfy flow. A correlative evaluation between flow and response to stereotactic radiosurgery was carried out. Phase contrast angiograms were obtained at flow velocities of 400, 200, 100, 60 and 20 cm/sec. The fractionated velocities provided images that selectively demonstrated the arterial and venous components of the arteriovenous malformations. Qualitative assessment of the velocity within the arteriovenous malformations and the presence of fistulae were also determined by multiple velocity images. In addition, 3-dimensional time-of-flight magnetic resonance angiograms were obtained to define the exact size and shape of the nidus. This technique also permitted evaluation of the nidus and feeding arteries for the the presence of low flow aneurysms. Correlation between the two imaging modalities was carried out by subjective and semiquantitative estimation of flow velocity and estimation of nidus size. The following velocity parameters were employed: fast, intermediate, slow, and none. Early analysis suggests that slower flowing arteriovenous malformations may obliterate faster after stereotactic radiosurgery an flow parameters should be employed to predict response. In conclusion, magnetic resonance angiography permits semiquantitative flow velocity assessment and may therefore be superior to stereotactic angiography. An additional advantage of magnetic resonance angiography is the generation of serial transverse images which can replace the conventional CT scan employed for stereotactic radiosurgery treatment planning. A single diagnostic test may therefore be used for diagnosis, radiosurgical treatment planning, follow-up, and treatment selection by identifying patients likely to respond early to radiosurgical management

Protective effect of remote limb ischemic perconditioning on the liver grafts of rats with a novel model.

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Junjun Jia

Full Text Available Remote ischemic conditioning (RIC is a known manual conditioning to decrease ischemic reperfusion injury (IRI but not increase ischemic time. Here we tried to establish a rat RIC model of liver transplantation (LT, optimize the applicable protocols and investigate the protective mechanism.The RIC model was developed by a standard tourniquet. Sprague-Dawley rats were assigned randomly to the sham operated control (N, standard rat liver transplantation (OLT and RIC groups. According to the different protocols, RIC group was divided into 3 subgroups (10 min×3, n = 6; 5 min×3, n = 6; 1 min×3, n = 6 respectively. Serum transaminases (ALT, AST, creatine kinase (CK, histopathologic changes, malondialdehyde (MDA, myeloperoxidase (MPO and expressions of p-Akt were evaluated.Compared with the OLT group, the grafts subjected to RIC 5min*3 algorithm showed significant reduction of morphological damage and improved the graft function. Also, production of reactive oxygen species (MDA and neutrophil accumulation (MPO were markedly depressed and p-Akt was upregulated.In conclusion, we successfully established a novel model of RIC in rat LT, the optimal RIC 5min*3 algorithm seemed to be more efficient to alleviate IRI of the liver graft in both functional and morphological categories, which due to its antioxidative, anti-inflammation activities and activating PI3K Akt pathway.

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

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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.

Chloroanthraquinone as a grafted probe molecule to investigate grafting yield on carbon powder

International Nuclear Information System (INIS)

Le Comte, Annaïg; Brousse, Thierry; Bélanger, Daniel

2016-01-01

Spontaneous grafting of chloroanthraquinone (ClAQ) groups on Black Pearls carbon by reduction of the corresponding in-situ generated diazonium cations was successfully achieved. The presence of an halogen atom on the quinone molecule allowed the use of different spectroscopic characterization techniques to determine the accurate quinone content of the modified carbon. Electrochemical characterization highlighted that the presence of chlorine atom on the grafted molecule did not affect the electrochemical response or the grafting reaction efficiency. The amount of ClAQ molecules at the carbon surface after grafting was determined by cyclic voltammetry, together with thermogravimetric analysis coupled mass spectroscopy, X-ray photoelectron spectroscopy and elemental analysis. The ClAQ mass loadings estimated from the four techniques are in very good agreement and confirm that the grafted moieties are all electrochemically active and accessible. Finally, the grafting of quinone-type molecule using the reduction of diazonium cations does not affect the electroactivity of the grafted groups and cyclic voltammetry can be considered as a reliable technique to evaluate the mass loading of grafted quinone groups on porous carbon. Thus ClAQ can be used as a grafted probe molecule to investigate grafting yield on carbon powder, and this approach can be extended to functionalized electrodes used in an increasing number of electrochemical energy storage devices.

Synovial Mesenchymal Stem Cells Promote Meniscus Regeneration Augmented by an Autologous Achilles Tendon Graft in a Rat Partial Meniscus Defect Model

Science.gov (United States)

Ozeki, Nobutake; Muneta, Takeshi; Matsuta, Seiya; Koga, Hideyuki; Nakagawa, Yusuke; Mizuno, Mitsuru; Tsuji, Kunikazu; Mabuchi, Yo; Akazawa, Chihiro; Kobayashi, Eiji; Saito, Tomoyuki; Sekiya, Ichiro

2015-01-01

Although meniscus defects and degeneration are strongly correlated with the later development of osteoarthritis, the promise of regenerative medicine strategies is to prevent and/or delay the disease's progression. Meniscal reconstruction has been shown in animal models with tendon grafting and transplantation of mesenchymal stem cells (MSCs); however, these procedures have not shown the same efficacy in clinical studies. Here, our aim was to investigate the ability of tendon grafts pretreated with exogenous synovial-derived MSCs to prevent cartilage degeneration in a rat partial meniscus defect model. We removed the anterior half of the medial meniscus and grafted autologous Achilles tendons with or without a 10-minute pretreatment of the tendon with synovial MSCs. The meniscus and surrounding cartilage were evaluated at 2, 4, and 8 weeks (n = 5). Tendon grafts increased meniscus size irrespective of synovial MSCs. Histological scores for regenerated menisci were better in the tendon + MSC group than in the other two groups at 4 and 8 weeks. Both macroscopic and histological scores for articular cartilage were significantly better in the tendon + MSC group at 8 weeks. Implanted synovial MSCs survived around the grafted tendon and native meniscus integration site by cell tracking assays with luciferase+, LacZ+, DiI+, and/or GFP+ synovial MSCs and/or GFP+ tendons. Flow cytometric analysis showed that transplanted synovial MSCs retained their MSC properties at 7 days and host synovial tissue also contained cells with MSC characteristics. Synovial MSCs promoted meniscus regeneration augmented by autologous Achilles tendon grafts and prevented cartilage degeneration in rats. Stem Cells 2015;33:1927–1938 PMID:25993981

Cartilage grafting in facial reconstruction with special consideration of irradiated grafts

International Nuclear Information System (INIS)

Donald, P.J.

1986-01-01

The search for the perfect facial implant for reconstruction of the face continues. Cartilage, once thought to be an undesirable graft material because of its propensity for absorption, has regained popularity in the past decade. Various preparation techniques have been employed to ensure graft sterility and diminished absorption. An improved understanding of cartilage structure and physiology has shed considerable light on the host-graft relationship. Gamma irradiation is a time-honored method of preservation. An experiment was undertaken to investigate the physiology of irradiated cartilage grafts following prolonged implantation on the facial skeleton of sheep and dog. Merthiolate preserved grafts were used as controls. Direct observation, histochemical techniques, autoradiography, and transmission electron micrography were used to determine chondrocyte viability and matrix composition. It was surprising to note that following implantation of 16 to 72 months, complete resorption was seen in 87.7% of the irradiated grafts and in 43.8% of the Merthiolate stored controls. Many of the grafts acquired chondrocytes from the host and produced new proteoglycan matrix as well as undergoing some degree of ossification. A comparison to the clinical situation in humans is made. 98 references

Intracranial arteriovenous malformation. Contralateral steal phenomena

Energy Technology Data Exchange (ETDEWEB)

Batjer, H H; Devous, M D; Seibert, G B; Purdy, P D; Ajmani, A K; Delarosa, M; Bonte, F J [Texas Univ., Dallas, TX (USA). Southwestern Medical Center

1989-05-01

Sixty-two patients with radiographically proven intracranial arteriovenous malformations underwent preoperative regional cerebral blood flow measurement with {sup 133}Xe signal-photon emission computed tomography. Contralateral regions of hypoperfusion were deteceted in all cases. Steal severity was assessed according to the contralateral steal index (ISteal(c)). ISteal(c) was < 0.7 (severe) in 22 (35%), 0.7-0.8 (intermediate) in 18 (29%), and > 0.8 (mild) in 22 (35%). ISteal(c) was more frequently severe or mild in females and more often intermediate in males in males (p < 0.05). Hyperemic complications were encountered more frequently in patients with intermediate ISteal(c) (p = 0.086). An unfavorable outcome was associated with less severe contralateral steal (p = 0.12). A detailed clinical, radiographic, and hemodynamic profile may help to preperatively identify patients at high risk for a poor surgical outcome. (author).

A rare cause of progressive paraparesis and urinary retention: Spinal dural arteriovenous fistula- Case report

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Sırma Geyik

2016-12-01

Full Text Available Spinal arteriovenous fistulas (AVF, are rarely seen clinical pathology, have serious morbidity in cases without treatment although spinal AVF are the most common types of spinal arteriovenous malformation. Fifty years old male patient suffered from urine retention and paraparesis after lifted a heavy object. Spinal magnetic resonance images (MRI showed diffuse hyper intense lesion from midthoracic spinal cord segment to conus medullaris in T2A sequance. Spinal angiography revealed a long segmental dorsal AVF on the right side of T 7-8 level in spinal cord. Because of the low flow and a small AVF neurosurgical Department decided to perform an operation for spinal AVF. We should keep in mind spinal AVF, in which prognosis is well after prompt and appropriate theraphy, as a differential diagnosis in patients presented with progressive spinal symptoms.

Radiosurgery of arteriovenous malformations

International Nuclear Information System (INIS)

Kawamoto, Shunsuke

1994-01-01

Steiner has first published a report of a case of cerebral arteriovenous malformation (AVM) treated with gamma knife radiosurgery in 1972. Since the mid-1980s, radiosurgery has increasingly received much attention. There have already been more than 6,000 radiosurgically treated AVM cases. This article reviews radiosurgery in the context of the following: (1) radiosurgery according to gamma knife, linear accelerator, heavy-charged particle Bragg-peak radiation and neutron; (2) therapeutic outcome in view of angiographically proven complete obliteration (CO) of AVM, including the time required for CO and factors regulating CO (such as the volume of AVM, radiation doses, correlation between the volume of AVM and radiation doses, age, and site of AVM), histopathological findings, and clinical complaints (such as headache and epilepsy) after radiosurgery; (3) bleeding after radiosurgery; (4) complications (including angiography-related complications, those immediately after radiosurgery, delayed complications, factors influencing delayed complications, and endocrine or growth retardation); (5) other problems (such as radiation doses, follow-up strategy, approaches to giant AVMs, and repeat irradiation); (6) indication of radiosurgery for lesions other than brain stem, and lesions of the mid-brain, pons and bulb. (N.K.) 134 refs

Arteriovenous malformation of face

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Ashok Kumar

2017-01-01

Full Text Available Arteriovenous malformations (AVMs are rare congenital vascular malformations accounting only 1.5% of all vascular anomalies with 50% occurrence in the oral and maxillofacial region. It usually results from birth defects of the vasculature. A literature search revealed only few case reports of AVMs in the facial region. Lack of meticulous diagnosis, scarcity of knowledge, and paucity of literature can result in their exsanguinations leading to fatal hemorrhagic incidents after various dental procedures such as tooth extraction, surgical intervention, puncture wound, or blunt injury in involved area. The present case describes the accidental diagnosis of asymptomatic high-flow AVMs in the facial region of pediatric patient reported primarily for the treatment of periapical abscess. This case report is unique because although there was no history of bleeding episodes, thorough examination and investigations diagnosed it as high-flow vascular malformation. It is important for the dental practitioner to be aware of AVM which may be present in the head and neck region that can produce fatal bleeding episodes during various dental procedures. Proper diagnosis of AVMs through complete history, precise clinical examination, and advanced imaging modalities can help in preventing serious life-threatening complications.

Vascular access for hemodialysis. Patency rates and results of revision.

Science.gov (United States)

Palder, S B; Kirkman, R L; Whittemore, A D; Hakim, R M; Lazarus, J M; Tilney, N L

1985-08-01

Over a 4-year interval, 324 arteriovenous conduits were created in 256 patients with end-stage renal disease as access for chronic hemodialysis. These included 154 Cimino fistulae, 163 polytetrafluoroethylene (PTFE) grafts, and seven miscellaneous grafts. Satisfactory patency rates were demonstrated for as long as 4 years for both Cimino fistulae and PTFE grafts by life-table analysis. Failures of Cimino fistulae usually occurred early in the postoperative period, secondary to attempts to use inadequate veins. Thrombosis caused the majority of PTFE graft failures and was generally the result of venous stenosis. Correction of such venous stenosis is mandatory to restore graft patency and can result in prolonged graft survival.

Transvenous sclerotherapy of peripheral arteriovenous malformations and hemangiomas

International Nuclear Information System (INIS)

Hunter, D.W.; Moradian, G.P.; Castaneda-Zuniga, W.R.; Amplantz, K.

1989-01-01

After exsanguination of the lesion and control of arterial inflow and venous outflow, the authors used a transvenous or direct puncture technique for injection of a sclerosing solution (3% sotradecol and ionic contrast material) to treat 18 patients with peripheral arteriovenous malformations or hemangiomas. The results are discussed. Good results were achieved in 12 patients. The other six patients had residual symptoms. Multiple treatment sessions were usually necessary. Short-term management included the use of intravenous heparin, steroids, and antibiotics. No significant long-term complications occurred. Short-term complications, including swelling, local pain, blistering, and localized deep venous thrombosis, occurred in 70% of the patients

Association of vascular access flow with short-term and long-term mortality in chronic haemodialysis patients: a retrospective cohort study

OpenAIRE

Wu, Chung-Kuan; Wu, Chia-Lin; Lin, Chia-Hsun; Leu, Jyh-Gang; Kor, Chew-Teng; Tarng, Der-Cherng

2017-01-01

Objectives To investigate the impact of vascular access flow (Qa) on vascular and all-cause mortality in chronic haemodialysis (HD) patients. Design Observational cohort study. Setting Single centre. Participants Adult chronic HD patients at the HD unit of Shin Kong Wu Ho-Su Memorial Hospital between 1 January 2003 and 31 December 2003 were recruited. Patients were excluded if they had arteriovenous fistula or arteriovenous graft failure within 3 months before the date of Qa measurement, were...

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. �

Novel anterior cruciate ligament graft fixation device reduces slippage

Directory of Open Access Journals (Sweden)

Lopez MJ

2013-05-01

Full Text Available Mandi J Lopez,1 Allen Borne,2 W Todd Monroe,3 Prakash Bommala,1 Laura Kelly,1 Nan Zhang11Laboratory for Equine and Comparative Orthopedic Research, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, 2Louisiana State University, New Orleans Health Sciences Center, School of Medicine, New Orleans, 3Department of Biological and Agricultural Engineering, Agricultural Center, Louisiana State University, Baton Rouge, LA, USAAbstract: Clinically significant laxity occurs in 10%–30% of knees after anterior cruciate ligament reconstruction. Graft slippage and tension loss at the hamstring graft tibial fixation site during and after reconstruction surgery contribute to postoperative joint laxity and are detrimental to long-term knee stability and graft properties. Limiting graft slippage will reduce associated complications. We sought to compare the in vitro mechanical properties and in vivo joint stabilization, postoperative limb use, and graft incorporation of the novel GraftGrab™ (GG device designed to reduce hamstring graft tibial fixation slippage with the commercially available bioabsorbable Bio-Post™ and spiked washer (BP. Mechanical testing was performed on canine tibia-hamstring graft constructs to quantify initial fixation properties. In vivo joint stabilization, postoperative limb use and graft incorporation of hamstring graft reconstructions were determined in a canine model. Outcomes included tibial translation and ground reaction forces preoperatively and 4 and 8 weeks postoperatively, three-dimensional graft and bone tunnel dimensions at the latter two time points, and graft-bone microstructure, as well as mechanical properties 8 weeks after implantation. Immediately after fixation, all grafts slipped from the BP constructs versus about 30% of GG constructs. In vivo limb use remained low, and tibial translation increased with time in the BP cohort. These results together

Impact of top end anastomosis design on patency and flow stability in coronary artery bypass grafting.

Science.gov (United States)

Koyama, Sachi; Kitamura, Tadashi; Itatani, Keiichi; Yamamoto, Tadashi; Miyazaki, Shohei; Oka, Norihiko; Nakashima, Kouki; Horai, Tetsuya; Ono, Minoru; Miyaji, Kagami

2016-05-01

For coronary artery bypass grafting (CABG), free grafts such as a saphenous vein or radial artery are often used for grafts to the lateral and posterior walls. However, the relationship between top-end anastomosis design and long-term patency remains unknown. Because coronary artery blood flow is dominant during diastole, top-end anastomosis may work better if the graft is directed towards the apex, whereas the shortest graft pathway appears to be most efficient. Using computational fluid dynamic models, we evaluated the hemodynamic variables that were affected by the angle of the top-end anastomosis. We created three-dimensional geometries of the aortic root with coronary arteries that involved 75 % stenosis in the obtuse marginal and postero-lateral branches. Two bypass models under vasodilator administration were created: in a"Model A", the top-end anastomosis is parallel to the long axis of the ascending aorta and the graft passed over the conus directed towards the apex; in a "Model B", the top-end anastomosis is directed toward the shortest pathway, and form near the right angles to the long axis of the ascending aorta. Wall shear stress (WSS) and its fluctuation, an oscillatory shear index (OSI) were evaluated to predict fibrosis progression at the anastomosis site and graft flow. Graft flow was 197.3 ml/min and 207.3 ml/min in the "Model A" and "Model B", respectively. The minimal WSS value inside the graft with the "Model A" and "Model B" was 0.53 Pa and 4.09 Pa, respectively, and the OSI value was 0.46 and 0.04, respectively. The top-end anastomosis of a free graft should be directed vertically towards the aorta to achieve the shortest graft pathway to maintain a high graft flow rate and to avoid the risks of endothelial fibrosis and plaque progression over the long-term after CABG.

In vivo outcomes of tissue-engineered osteochondral grafts.

Science.gov (United States)

Bal, B Sonny; Rahaman, Mohamed N; Jayabalan, Prakash; Kuroki, Keiichi; Cockrell, Mary K; Yao, Jian Q; Cook, James L

2010-04-01

Tissue-engineered osteochondral grafts have been synthesized from a variety of materials, with some success at repairing chondral defects in animal models. We hypothesized that in tissue-engineered osteochondral grafts synthesized by bonding mesenchymal stem cell-loaded hydrogels to a porous material, the choice of the porous scaffold would affect graft healing to host bone, and the quality of cell restoration at the hyaline cartilage surface. Bone marrow-derived allogeneic mesenchymal stem cells were suspended in hydrogels that were attached to cylinders of porous tantalum metal, allograft bone, or a bioactive glass. The tissue-engineered osteochondral grafts, thus created were implanted into experimental defects in rabbit knees. Subchondral bone restoration, defect fill, bone ingrowth-implant integration, and articular tissue quality were compared between the three subchondral materials at 6 and 12 weeks. Bioactive glass and porous tantalum were superior to bone allograft in integrating to adjacent host bone, regenerating hyaline-like tissue at the graft surface, and expressing type II collagen in the articular cartilage.

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

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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.

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

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.

Medical chilling device designed for hypothermic hydration graft storage system: Design, thermohydrodynamic modeling, and preliminary testing

Energy Technology Data Exchange (ETDEWEB)

Seo, Jung Hwan [Hongik University, Seoul (Korea, Republic of)

2015-02-15

Hypothermic hydration graft storage is essential to reduce the metabolic demand of cells in vitro. The alleviated metabolic demands reduce the emergence rate of anaerobic metabolism generating adenosine triphosphate (ATP) energy that creates free radicals. The cessive free radicals can damage cells and tissues due to their highly oxidative power with molecules. Current cooling systems such as a conventional air cooling system and an ice pack system are inappropriate for chilling cell tissues in vitro because of inconvenience in use and inconsistent temperature sustainability caused by large size and progressive melting, respectively. Here, we develop a medical chilling device (MCD) for hypothermic hydration graft storage based on thermo-hydrodynamic modeling and thermal electric cooling technology. Our analysis of obtained hydrodynamic thermal behavior of the MCD revealed that the hypothermic condition of 4 .deg. C was continuously maintained, which increased the survival rates of cells in vitro test by reduced free radicals. The validated performance of the MCD promises future development of an optimal hypothermic hydration graft storage system designed for clinical use.

Dynamics of solvent-free grafted nanoparticles

KAUST Repository

Chremos, Alexandros

2012-01-01

The diffusivity and structural relaxation characteristics of oligomer-grafted nanoparticles have been investigated with simulations of a previously proposed coarse-grained model at atmospheric pressure. Solvent-free, polymer-grafted nanoparticles as well as grafted nanoparticles in a melt were compared to a reference system of bare (ungrafted) particles in a melt. Whereas longer chains lead to a larger hydrodynamic radius and lower relative diffusivity for grafted particles in a melt, bulk solvent-free nanoparticles with longer chains have higher relative diffusivities than their short chain counterparts. Solvent-free nanoparticles with short chains undergo a glass transition as indicated by a vanishing diffusivity, diverging structural relaxation time and the formation of body-centered-cubic-like order. Nanoparticles with longer chains exhibit a more gradual increase in the structural relaxation time with decreasing temperature and concomitantly increasing particle volume fraction. The diffusivity of the long chain nanoparticles exhibits a minimum at an intermediate temperature and volume fraction where the polymer brushes of neighboring particles overlap, but must stretch to fill the interparticle space. © 2012 American Institute of Physics.

Bragg peak proton beam treatment of arteriovenous malformations of the brain

International Nuclear Information System (INIS)

Kjellberg, R.N.; Poletti, C.E.; Roberson, G.H.; Adams, R.D.

1978-01-01

This report describes 27 patients treated for arteriovenous malformations of the brain by the Bragg Peak proton beam method during the past 12 years. The authors are led to a measure of confidence that Bragg Peak proton therapy can be provided without lethal risk attributed to the procedure. In 21 patients no neurological change has occurred, two patients experienced neurological improvement and four have developed new neurological abnormalities considered complications of the therapy. (Auth.)

Carpal tunnel syndrome: a complication of arteriovenous fistula in hemodialysis patients.

Science.gov (United States)

Kumar, S.; Trivedi, H. L.; Smith, E. K.

1975-01-01

Symptoms of compression of the median nerve in the carpal tunnel developed in two patients in whom an arteriovenous fistula was created to alleviate chronic renal failure through hemodialysis. Anatomic changes in the wrist area due to the fistula are probably important in the development of this syndrome, and pre-existing uremic peripheral polyneuropathy may also be important in the early development of local symptoms of nerve damage. Images FIG. 1 PMID:1201544

A COMPARATIVE STUDY OF TYMPANOPLASTY USING SLICED CARTILAGE GRAFT VS. TEMPORALIS FASCIA GRAFT

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Rahul Ashok Telang

2018-02-01

Full Text Available BACKGROUND The objective of the study was to compare the hearing improvement after using sliced cartilage graft with that of temporalis fascia and to compare the graft take-up between the two graft materials. MATERIALS AND METHODS A prospective clinical study including 60 patients with chronic mucosal otitis media, who were selected randomly from the outpatient department, after obtaining their consent were divided into 2 groups of 30 each, and evaluated according the study protocol. Their pre-operative audiometry was recorded and both groups of patients underwent surgery with one of the graft materials- temporalis fascia or sliced tragal cartilage with a thickness of 0.5 mm. All patients were regularly followed up and post-operative audiometry was done at 3 months. The hearing improvement in the form of closure of air-bone-gap and graft take-up was analysed statistically. RESULTS The temporalis fascia graft group had a pre-operative ABG of 22.33 ± 6.24 dB and post-operative ABG of 12.33 ± 4.72 dB with hearing improvement of 10.00 dB. The sliced cartilage graft group had a pre-operative ABG of 20.77 ± 5.75 dB and postoperative ABG of 10.50 ± 4.46 dB with hearing improvement of 10.27 dB. In the temporalis fascia group, 28 (93.3% patients had good graft take-up and in the sliced cartilage group 29 (96.7% had good graft take-up. There was statistically significant hearing improvement in both of our study groups but there was no statistically significant difference between the two groups. There was no statistically significant difference in graft take-up also. CONCLUSION Sliced cartilage graft is a good auto-graft material in tympanoplasty, which can give good hearing improvement and has good graft take-up, which is comparable with that of temporalis fascia.

Pathogenesis of arteriovenous malformations in the absence of endoglin.

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Mahmoud, Marwa; Allinson, Kathleen R; Zhai, Zhenhua; Oakenfull, Rachael; Ghandi, Pranita; Adams, Ralf H; Fruttiger, Marcus; Arthur, Helen M

2010-04-30

Arteriovenous malformations (AVMs) result in anomalous direct blood flow between arteries and veins, bypassing the normal capillary bed. Depending on size and location, AVMs may lead to severe clinical effects including systemic cyanosis (pulmonary AVMs), hemorrhagic stroke (cerebral AVMs) and high output cardiac failure (hepatic AVMs). The factors leading to AVM formation are poorly understood, but patients with the familial disease hereditary hemorrhagic telangiectasia (HHT) develop AVMs at high frequency. As most HHT patients have mutations in ENG (endoglin) or ACVRL1 (activin receptor-like kinase 1), a better understanding of the role of these genes in vascular development is likely to reveal the etiology of AVM formation. Using a mouse with a conditional mutation in the Eng gene, we investigated the sequence of abnormal cellular events occurring during development of an AVM. In the absence of endoglin, subcutaneous Matrigel implants in adult mice were populated by reduced numbers of new blood vessels compared with controls, and resulted in local venous enlargement (venomegaly). To investigate abnormal vascular responses in more detail, we turned to the more readily accessible vasculature of the neonatal retina. Endoglin-deficient retinas exhibited delayed remodeling of the capillary plexus, increased proliferation of endothelial cells and localized AVMs. Muscularization of the resulting arteriovenous shunts appeared to be a secondary response to increased blood flow. AVMs develop when an angiogenic stimulus is combined with endoglin depletion. Moreover, AVM formation appears to result from the combination of delayed vascular remodeling and an inappropriate endothelial cell proliferation response in the absence of endoglin.

Posttraumatic growth in post-surgical coronary artery bypass graft patients

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Catherine A Waight

2015-02-01

Full Text Available Recent research in posttraumatic growth has been applied to people with life-threatening illnesses to optimise recovery. There is a lack of research exploring posttraumatic growth in coronary artery bypass graft patients. This article describes the recovery experience of 14 coronary artery bypass graft patients (13 males and 1 female at their first outpatient review post-surgery. Grounded theory analysis was used to develop a model of distinct and shared pathways to growth depending on whether patients were symptomatic or asymptomatic pre-coronary artery bypass graft. Outcomes of posttraumatic growth in this sample included action-based healthy lifestyle growth and two forms of cognitive growth: appreciation of life and new possibilities. The model of posttraumatic growth developed in this study may be helpful in guiding future research into promoting posttraumatic growth and behaviour change in coronary artery bypass graft patients.

Computerized transverse tomography of vascular lesions of the brain. I. Arteriovenous malformations

International Nuclear Information System (INIS)

Pressman, B.D.; Kirkwood, J.R.; Davis, D.O.

1975-01-01

Computerized transverse tomography (CTT) of the brain is a recently developed method which allows non-invasive roentgenologic evaluation of intracranial disease. Since its inception, major attention has been given to the diagnosis and evaluation of tumors, clots, infarcts, venticular size, and orbital lesions. The purpose of this report is to discuss the application of CTT to the diagnosis and evaluation of intracerebral arteriovenous malformations. (U.S.)

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

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

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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.

Fístula arteriovenosa pós-nefrolitotripsia percutânea Arteriovenous fistula after percutaneous nephrolithotomy

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Luis Alberto Batista Peres

2009-09-01

Full Text Available Fístula arteriovenosa (FAV é uma rara complicação pós-nefrolitotripsia percutânea (NLP. Apresentamos o caso de um paciente de 70 anos, sexo masculino, que apresentou sangramento maciço após NLP, tratado por angioembolização renal superseletiva com implante de stent. Após a embolização, houve resolução do sangramento. FAV é uma complicação incomum da NLP, que pode ser tratada com sucesso com angioembolização.Arteriovenous fistula (AVF is a rare complication of percutaneous nephrolithotomy (PNL. We report the case of a 70-year-old man, who had massive bleeding after PNL and underwent treatment with superselective renal angiographic embolization and stent implantation. Bleeding resolved after embolization. Arteriovenous fistula is an uncommon complication of PNL, which may be successfully treated with angiographic embolization.

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

International Nuclear Information System (INIS)

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

1988-01-01

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

Treat high cervical spinal arteriovenous malformation with Cyberknife radiosurgery

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Yu-Fen Huang

2014-01-01

Full Text Available This paper describes the use of CyberKnife radiosurgery in the treatment of accidentally found cervical spinal arteriovenous malformation (AVM. We present the case of a patient with cervical spinal AVM, who developed progressive neck pain, gait disturbance, urine and stool incontinence 2 weeks after the fell down accident. The patient underwent CyberKnife radiosurgery. After CyberKnife radiosurgery for 2 years, the patient′s neck pain diminished and was able to keep the walk without any assistance. The management of cervical spinal AVM varies. This patient demonstrated a successful treatment of cervical spinal AVM with CyberKnife radiosurgery.

The self-care with arteriovenous Fistula conducted by chronic renal failure.patients in the southern region of Mato Grosso.

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Camila Aoki Reinas

2012-01-01

Full Text Available The objective of the study is know the care with the arteriovenous fistula carried by the patient with chronic renal and the role of a nurse care to such. Is a descriptive, exploratory study of qualitative approach, developed with 20 patients in a dialysis clinic in Rondonópolis (MT, through individual interviews using a semi structured questionnaire. The analysis of the data was content analysis as categorical recommended by Bardin, resulting in two categories: self care with arteriovenous fistula and nurses in health education. In the category of self-care with the arteriovenous fistula, 70% received guidance about the care of the fistula with the nurse, the care most often mentioned was "no catch weight." However, when asked about the reason for the realization of such care, a large part could not explain. In the category of the nurse in health education, the nurse was quoted once as exclusively responsible for the guidelines on caring for the FAV. Considering the results, there was lack of information of these patients, regarding the reasons for the need to care of it, which is more worrying.

Extensive white matter changes after stereotactic radiosurgery for brain arteriovenous malformations: a prognostic sign for obliteration?

NARCIS (Netherlands)

van den Berg, R.; Buis, D. R.; Lagerwaard, F. J.; Lycklama a Nijeholt, G. J.; Vandertop, W. P.

2008-01-01

OBJECTIVE: Perinidal high-signal-intensity changes on T2-weighted magnetic resonance imaging can be seen surrounding radiosurgically treated brain arteriovenous malformations (AVM). Occasionally, these signal intensity changes develop far beyond the irradiated volume. A retrospective analysis of

Extensive White Matter Changes After Stereotactic Radiosurgery for Brain Arteriovenous Malformations: A Prognostic Sign for Obliteration?

NARCIS (Netherlands)

van den Berg, R.; Buis, D.R.; Lagerwaard, F.J.; Nijeholt, G.J.L.A.; Vandertop, W.P.

2008-01-01

OBJECTIVE: Perinidal high-signal-intensity changes on T2-weighted magnetic resonance imaging can be seen surrounding radiosurgically treated brain arteriovenous malformations (AVM). Occasionally, these signal intensity changes develop far beyond the irradiated volume. A retrospective analysis of

Insolubilisation of biologically active materials with novel radiation graft copolymers

International Nuclear Information System (INIS)

Garnett, J.L.; Jankiewicz, S.V.; Levot, R.; Sangster, D.F.

1984-01-01

The use of radiation grafting to immobilise a typical enzyme, trypsin, is reported. The technique involves radiation grafting to a backbone polymer a monomer containing an appropriate functional group to which the enzyme is bonded. In the present work, p-nitrostyrene has been grafted to representative trunk polymers, polypropylene and PVC, the nitro group in the resulting copolymer converted to the isothiocyanato derivative to which trypsin is attached. Of importance to this insolubilisation process, especially for radiation sensitive backbone polymers, is the inclusion of additives which enhance grafting. A new class of additives which increase the grafting yields is reported using as representative backbone polymers, naturally occurring cellulose and synthetic low density polyethylene. The new additives are specific metal salts such as LiClO 4 . The reactivity of these salts in grafting enhancement has been compared with that of mineral acid which has previously been used as an additive to increase grafting yields in both preirradiation and simultaneous techniques. A new model for grafting enhancement in the presence of the metal salts as well as acids is proposed whereby increased grafting yields are attributed to increased partitioning of monomer into the graft region in the presence of ionic solutes. The value of these additives in preparing copolymers suitable for general reagent insolubilisation reactions is discussed

Compression and contact area of anterior strut grafts in spinal instrumentation: a biomechanical study.

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Pizanis, Antonius; Holstein, Jörg H; Vossen, Felix; Burkhardt, Markus; Pohlemann, Tim

2013-08-26

Anterior bone grafts are used as struts to reconstruct the anterior column of the spine in kyphosis or following injury. An incomplete fusion can lead to later correction losses and compromise further healing. Despite the different stabilizing techniques that have evolved, from posterior or anterior fixating implants to combined anterior/posterior instrumentation, graft pseudarthrosis rates remain an important concern. Furthermore, the need for additional anterior implant fixation is still controversial. In this bench-top study, we focused on the graft-bone interface under various conditions, using two simulated spinal injury models and common surgical fixation techniques to investigate the effect of implant-mediated compression and contact on the anterior graft. Calf spines were stabilised with posterior internal fixators. The wooden blocks as substitutes for strut grafts were impacted using a "pressfit" technique and pressure-sensitive films placed at the interface between the vertebral bone and the graft to record the compression force and the contact area with various stabilization techniques. Compression was achieved either with posterior internal fixator alone or with an additional anterior implant. The importance of concomitant ligament damage was also considered using two simulated injury models: pure compression Magerl/AO fracture type A or rotation/translation fracture type C models. In type A injury models, 1 mm-oversized grafts for impaction grafting provided good compression and fair contact areas that were both markedly increased by the use of additional compressing anterior rods or by shortening the posterior fixator construct. Anterior instrumentation by itself had similar effects. For type C injuries, dramatic differences were observed between the techniques, as there was a net decrease in compression and an inadequate contact on the graft occurred in this model. Under these circumstances, both compression and the contact area on graft could only

Modification of polyetherurethane for biomedical application by radiation-induced grafting. I. Grafting procedure, determination of mechanical properties, and chemical modification of grafted films

International Nuclear Information System (INIS)

Jansen, B.; Ellinghorst, G.

1985-01-01

Radiation grafting of monomers onto suitable trunk polymers is a useful tool for tailoring new polymers for special purposes. This technique has been used in the past for the development of biocompatible materials, e.g., by grafting hydrogels onto mechanically stable polymers. In this first part of our work, the radiation grafting of hydrophilic or reactive monomers onto a polyetherurethane film using the pre-swelling technique is described. Following this technique the trunk polymer was swollen in the monomer before irradiation. As monomers 2-hydroxyethyl methacrylate (HEMA), 2,3-epoxypropyl methacrylate (GMA), 2,3-dihydroxypropyl methacrylate (GOMA), and acrylamide (AAm) were used. The kinetics of the grafting reactions were examined, and the distribution of the graft component inside the trunk polymer was investigated by means of infrared (IR) spectroscopy. Surface-grafted as well as bulk- and surface-grafted products could be obtained. The mechanical behavior of the grafted films--especially in the water-swollen state--was examined and compared with that of the pure trunk polymer. In nearly all cases it was found that the tensile strength sigma B and the elongation at break epsilon R decreases as the grafting yield increases. Modification of GMA- and AAm-grafted films via chemical reactions was performed to create new functional groups of biomedical interest. In this manner a diol structure, a carboxylic acid structure, and a sulfonic acid group could be introduced in the grafted polymer. The water uptake of such modified films is increased markedly when compared with that of the unmodified samples

Dural arteriovenous fistula presenting with exophthalmos and seizures.

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Feyissa, Anteneh M; Ponce, Lucido L; Patterson, Joel T; Von Ritschl, Rudiger H; Smith, Robert G

2014-03-15

Concomitant seizures and exophthalmos in the context of a temporal dural arteriovenous fistula (dAVF) has not been described before. Here, we report a 55-year-old-male who presented with an 8-month history of progressive painless exophthalmos of his left eye, conjunctival chemosis, reduced vision and new onset complex partial seizures. Cerebral angiography demonstrated Cognard Type IIa left cerebral dAVF fed by branches from the left occipital artery and an accessory meningeal artery, with drainage to the superior ophthalmic vein. Following surgical obliteration of dAVF feeding vessels, our patient had dramatic improvement in visual acuity, proptosis and chemosis along with cessation of clinical seizures. Published by Elsevier B.V.

Evolution of shear stress, protein expression, and vessel area in an animal model of arterial dilatation in hemodialysis grafts

Science.gov (United States)

Misra, Sanjay; Fu, Alex A.; Misra, Khamal D.; Glockner, James F.; Mukhopadyay, Debabrata

2010-01-01

Purpose To evaluate the wall shear stress, protein expression of matrix metalloproteinases-2 (MMP-2), -9 (MMP-9), and the inhibitors (tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), and -2 (TIMP-2)), and vessel area over time in a porcine model for hemodialysis polytetrafluoroethylene (PTFE) grafts. Materials and methods In 21 pigs, subtotal renal infarction was performed and 28 days later, a PTFE graft was placed to connect the carotid artery to the ipsilateral jugular vein. Phase contrast MR was used to measure blood flow and vessel area at 1, 3, 7, and 14 days after graft placement. Wall shear stress was estimated from Poiseuille’s law. Animals were sacrificed at day 3 (N=7), day 7 (N=7), and day 14 (N=7) and expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 were determined at the grafted and control arteries. Results The mean wall shear stress of the grafted artery was higher than the control artery at all time points (P<0.05). It peaked by day 3 and decreased by days 7–14 as the vessel area nearly doubled. By days 7–14, there was a significant increase in active MMP-2 followed by a significant increase in pro and active MMP-9 by day 14 (P<0.05, grafted artery versus control). TIMP-1 expression peaked by day 7 and then decreased while TIMP-2 expression was decreased at days 7–14. Conclusions The wall shear stress of the grafted artery peaks by day 3 with increased MMP-2 activity by days 7–14 followed by pro and active MMP-9 by day 14 and the vessel area nearly doubled. PMID:20123196

Embryonic Cell Grafts in a Culture Model of Spinal Cord Lesion: Neuronal Relay Formation is Essential for Functional Regeneration

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Anne Tscherter

2016-09-01

Full Text Available Presently there exists no cure for spinal cord injury. However, transplantation of embryonic tissue into spinal cord lesions resulted in axon outgrowth across the lesion site and some functional recovery, fostering hope for future stem cell therapies. Although in vivo evidence for functional recovery is given, the exact cellular mechanism of the graft support remains elusive: either the grafted cells provide a permissive environment for the host tissue to regenerate itself or the grafts actually integrate functionally into the host neuronal network reconnecting the separated spinal cord circuits. We tested the two hypotheses in an in vitro spinal cord lesion model that is based on propagation of activity between two rat organotypic spinal cord slices in culture. Transplantation of dissociated cells from E14 rat spinal cord or forebrain re-established the relay of activity over the lesion site and, thus, provoked functional regeneration. Combining patch-clamp recordings from transplanted cells with network activity measurements from the host tissue on multi-electrode arrays we here show that neurons differentiate from the grafted cells and integrate into the host circuits. Optogenetic silencing of neurons developed from transplanted embryonic mouse forebrain cells provides clear evidence that they replace the lost neuronal connections to relay and synchronize activity between the separated spinal cord circuits. In contrast, transplantation of neurospheres induced neither the differentiation of mature neurons from the grafts nor an improvement of functional regeneration. Together these findings suggest, that the formation of neuronal relays from grafted embryonic cells is essential to re-connect segregated spinal cord circuits.

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

Posterior cranial fossa arteriovenous fistula with presenting as caroticocavernous fistula

Energy Technology Data Exchange (ETDEWEB)

Liu, H M; Shih, H C; Huang, Y C; Wang, Y H [Dept. of Medical Imaging, National Taiwan University Hospital, Taipei (Taiwan)

2001-05-01

We report cases of posterior cranial fossa arteriovenous fistula (AVF) with presenting with exophthalmos, chemosis and tinnitus in 26- and 66-year-old men. The final diagnoses was vertebral artery AVF and AVF of the marginal sinus, respectively. The dominant venous drainage was the cause of the unusual presentation: both drained from the jugular bulb or marginal sinus, via the inferior petrosal and cavernous sinuses and superior ophthalmic vein. We used endovascular techniques, with coils and liquid adhesives to occlude the fistulae, with resolution of the symptoms and signs. (orig.)

Posterior cranial fossa arteriovenous fistula with presenting as caroticocavernous fistula

International Nuclear Information System (INIS)

Liu, H.M.; Shih, H.C.; Huang, Y.C.; Wang, Y.H.

2001-01-01

We report cases of posterior cranial fossa arteriovenous fistula (AVF) with presenting with exophthalmos, chemosis and tinnitus in 26- and 66-year-old men. The final diagnoses was vertebral artery AVF and AVF of the marginal sinus, respectively. The dominant venous drainage was the cause of the unusual presentation: both drained from the jugular bulb or marginal sinus, via the inferior petrosal and cavernous sinuses and superior ophthalmic vein. We used endovascular techniques, with coils and liquid adhesives to occlude the fistulae, with resolution of the symptoms and signs. (orig.)

Ischemic stroke in combined cerebrovascular abnormalities - aneurysm of the right internal carotid artery and arteriovenous malformation temporo occipital in the right hemisphere

International Nuclear Information System (INIS)

Manolova, T.; Naydenov, K.; Manchev, I.; Manchev, L.

2016-01-01

A case of combined vascular abnormalities is presented- an aneurysm of the internal carotid artery and arterio-venous malformation temporooccipitally on the right, clinically presented by an ischemic brain stroke in the territory supplied by the right middle cerebral artery. Treatment included - hypo-tensive drugs, antiplatelet (antiaggregants) agents and vasodilators, which lead to significant improvement of the general and focal neurological symptoms. Neurosurgical intervention is been discussed, in order to remove the vascular malformation and to prevent future vascular events. Key words: Aneurysm. Arteriovenous Malformation. Ischemic Stroke

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.

Ruptured cervical arteriovenous fistulas presenting with subarachnoid hemorrhage and quadriplegia: an uncommon case.

Science.gov (United States)

Liu, Chien-Liang; Su, Yung-Cheng; Chen, Chien-Chih; Chong, Chee-Fah; Wang, Tzong-Luen

2008-02-01

Nontraumatic subarachnoid hemorrhage is a neurologic emergency, and prompt treatment is necessary to avoid catastrophic result. We present a patient with subarachnoid hemorrhage caused by ruptured cervical intradural extramedullary arteriovenous fistulas, which rapidly progressed to quadriplegia. Because of the timely management, the patient had a good recovery. This is a rare but important case that emergency physicians should be aware of.

Splenic arteriovenous malformation manifested by thrombocytopenia in hereditary hemorrhagic telangiectasia: a case report

Energy Technology Data Exchange (ETDEWEB)

Kwon, Hee Jin; Choi, Jong Cheol; Oh, Jong Yeong; Cho, Jin Han; Kang, Myong Jin; Lee, Jin Hwa; Yoon, Seong Kuk; Nam, Kyeong Jin [College of Medicine, Dong-A University, Busan (Korea, Republic of)

2008-09-15

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant inherited disease characterized by epistaxis, telangiectases and visceral arteriovenous malformations (AVMs). The involvement of the gastrointestinal tract, liver, lung and cerebrum for HHT has been described, whereas little is known about AVMs of the spleen. We report here the radiological findings of a case of a splenic AVM manifested by thrombocytopenia in HHT.

Splenic arteriovenous malformation manifested by thrombocytopenia in hereditary hemorrhagic telangiectasia: a case report

International Nuclear Information System (INIS)

Kwon, Hee Jin; Choi, Jong Cheol; Oh, Jong Yeong; Cho, Jin Han; Kang, Myong Jin; Lee, Jin Hwa; Yoon, Seong Kuk; Nam, Kyeong Jin

2008-01-01

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant inherited disease characterized by epistaxis, telangiectases and visceral arteriovenous malformations (AVMs). The involvement of the gastrointestinal tract, liver, lung and cerebrum for HHT has been described, whereas little is known about AVMs of the spleen. We report here the radiological findings of a case of a splenic AVM manifested by thrombocytopenia in HHT

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)

Bone grafts in dentistry

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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.

Penile Inversion Vaginoplasty with or without Additional Full-Thickness Skin Graft: To Graft or Not to Graft?

Science.gov (United States)

Buncamper, Marlon E; van der Sluis, Wouter B; de Vries, Max; Witte, Birgit I; Bouman, Mark-Bram; Mullender, Margriet G

2017-03-01

Penile inversion vaginoplasty is considered to be the gold standard for gender reassignment surgery in transgender women. The use of additional full-thickness skin graft as neovaginal lining is controversial. Some believe that having extra penile skin for the vulva gives better aesthetic results. Others believe that it gives inferior functional results because of insensitivity and skin graft contraction. Transgender women undergoing penile inversion vaginoplasty were studied prospectively. The option to add full-thickness skin graft is offered in patients where the penile skin length lies between 7 and 12 cm. Neovaginal depth was measured at surgery and during follow-up (3, 13, 26, and 52 weeks postoperatively). Satisfaction with the aesthetic result, neovaginal depth, and dilation regimen during follow-up were recorded. Satisfaction, sexual function, and genital self-image were assessed using questionnaires. A total of 100 patients were included (32 with and 68 without additional full-thickness skin graft). Patient-reported aesthetic outcome, overall satisfaction with the neovagina, sexual function, and genital self-image were not significantly associated with surgical technique. The mean intraoperative neovaginal depth was 13.8 ± 1.4 cm. After 1 year, this was 11.5 ± 2.5 cm. The largest decline (-15 percent) in depth is observed in the first 3 postoperative weeks (p skin graft use, in penile inversion vaginoplasty. The additional use of full-thickness skin graft does not influence neovaginal shrinkage, nor does it affect the patient- and physician-reported aesthetic or functional outcome. Therapeutic, IV.

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

Diversity of gut microflora is required for the generation of B cell with regulatory properties in a skin graft model.

Science.gov (United States)

Alhabbab, R; Blair, P; Elgueta, R; Stolarczyk, E; Marks, E; Becker, P D; Ratnasothy, K; Smyth, L; Safinia, N; Sharif-Paghaleh, E; O'Connell, S; Noelle, R J; Lord, G M; Howard, J K; Spencer, J; Lechler, R I; Lombardi, G

2015-06-25

B cells have been reported to promote graft rejection through alloantibody production. However, there is growing evidence that B cells can contribute to the maintenance of tolerance. Here, we used a mouse model of MHC-class I mismatched skin transplantation to investigate the contribution of B cells to graft survival. We demonstrate that adoptive transfer of B cells prolongs skin graft survival but only when the B cells were isolated from mice housed in low sterility "conventional" (CV) facilities and not from mice housed in pathogen free facilities (SPF). However, prolongation of skin graft survival was lost when B cells were isolated from IL-10 deficient mice housed in CV facilities. The suppressive function of B cells isolated from mice housed in CV facilities correlated with an anti-inflammatory environment and with the presence of a different gut microflora compared to mice maintained in SPF facilities. Treatment of mice in the CV facility with antibiotics abrogated the regulatory capacity of B cells. Finally, we identified transitional B cells isolated from CV facilities as possessing the regulatory function. These findings demonstrate that B cells, and in particular transitional B cells, can promote prolongation of graft survival, a function dependent on licensing by gut microflora.

Diversity of gut microflora is required for the generation of B cell with regulatory properties in a skin graft model

Science.gov (United States)

Alhabbab, R.; Blair, P.; Elgueta, R.; Stolarczyk, E.; Marks, E.; Becker, P. D.; Ratnasothy, K.; Smyth, L.; Safinia, N.; Sharif-Paghaleh, E.; O’Connell, S.; Noelle, R. J.; Lord, G. M.; Howard, J. K.; Spencer, J.; Lechler, R. I.; Lombardi, G.

2015-01-01

B cells have been reported to promote graft rejection through alloantibody production. However, there is growing evidence that B cells can contribute to the maintenance of tolerance. Here, we used a mouse model of MHC-class I mismatched skin transplantation to investigate the contribution of B cells to graft survival. We demonstrate that adoptive transfer of B cells prolongs skin graft survival but only when the B cells were isolated from mice housed in low sterility “conventional” (CV) facilities and not from mice housed in pathogen free facilities (SPF). However, prolongation of skin graft survival was lost when B cells were isolated from IL-10 deficient mice housed in CV facilities. The suppressive function of B cells isolated from mice housed in CV facilities correlated with an anti-inflammatory environment and with the presence of a different gut microflora compared to mice maintained in SPF facilities. Treatment of mice in the CV facility with antibiotics abrogated the regulatory capacity of B cells. Finally, we identified transitional B cells isolated from CV facilities as possessing the regulatory function. These findings demonstrate that B cells, and in particular transitional B cells, can promote prolongation of graft survival, a function dependent on licensing by gut microflora. PMID:26109230

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

Occupational therapy for patients with an arterio-venous fistula

Directory of Open Access Journals (Sweden)

Iustinian BENGULESCU

2017-03-01

Full Text Available End stage renal disease (ESRD represents a chronic medical condition that has become a public health problem and requires substantial funding. The number of patients with ESRD is rapidly increasing. From the moment that ESRD is diagnosed, the natural evolution of this pathology is towards mandatory dialysis, in absence of a renal transplant procedure. In order to perform hemodialysis, a vascular access site must be created and maintained functional. A proper vascular access site allows an adequate blood flow through the dialysis machine, in order to obtain the required results. The arterio-venous fistula represents the number one recommended vascular access site procedure. Establishing and maintaining a vascular access represents one of the biggest problems in hemodialysis. The arterio-venous fistula thus becomes the patient’s lifeline. Maintaining a good quality vascular access site is a demanding process and requires cooperation between both the patient and the health care providers. For ESRD patients there is a constant concern regarding the patency of their vascular access. The aim of this paper is to present the postoperative measures that ESRD patients should provide in order to preserve their vascular access. Also, we want to present the main signs of an early complication that patients should recognize and therefore immediately present themselves to the physician. By establishing this type of cooperation and trust between the patient and the medical staff we will be able to reduce the number of surgical procedures required for the creation and maintenance of the vascular access. Our final thought remains that a well-informed patient has better chances of prolonging his “lifeline”.

Complex arteriovenous malformation - a case report

International Nuclear Information System (INIS)

Sirakov, S.; Penkov, M.; Marinov, M.; Kamenov, B.

2014-01-01

AVMs are composed of a network of channels interposed between feeding arteries and draining veins, without any direct shunt. Two different anatomic types of nidus may be more or less differentiated: The most frequent clinical presentations of brain AVMs are hemorrhage, seizure, chronic headache, and focal deficits not related to hemorrhage. We show a case of 27 years old female came to the hospital in heavy condition with subarachnoid hemorrhage Fisher 4. She had a history of 4 surgical operation of brain AVM in the last 10 years, without significant reduction of the malformation. After discussion of multidisciplinary team, of neuroradiologist and neurosurgeon was decided to be perform endovascular embolization, because of the better outcome for the patient. We performed endovascular treatment of the AVM with achieving subtotal embolization of malformation (90%). The patient recovery completely after 22 days and went home. For the next 18 months follow up there is no data of accidents for the patient. Key words: Arteriovenous Malformation. Subarachnoid hemorrhage. Endovascular treatment. Embolization

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.

Additive effects in radiation grafting and curing

International Nuclear Information System (INIS)

Viengkhou, V.; Ng, L.

1996-01-01

Full text: Detailed studies on the accelerative effect of novel additives in radiation grafting and curing using acrylated monomer/oligomer systems have been performed in the presence of ionising radiation and UV as sources. Methyl methacrylate (MMA) is used as typical monomer for these grafting studies in the presence of the additives with model backbone polymers, cellulose and propropylene. Additives which have been found to accelerate these grafting processes are: mineral acid, occlusion compounds like urea, thermal initiators and photoinitiators as well as multifunctional monomers such as multifunctional acrylates. The results from irradiation with gamma rays have also been compared with irradiation from a 90W UV lamp. The role of the above additives in accelerating the analogous process of radiation curing has been investigated. Acrylated urethanes, epoxies and polyesters are used as oligomers together with acrylated monomers in this work with uv lamps of 300 watts/inch as radiation source. In the UV curing process bonding between film and substrate is usually due to physical forces. In the present work the presence of additives are shown to influence the occurrence of concurrent grafting during cure thus affecting the nature of the bonding of the cured film. The conditions under which concurrent grafting with UV can occur will be examined. A mechanism for accelerative effect of these additives in both grafting and curing processes has been proposed involving radiation effects and partitioning phenomena

Synthesis of Radiation Grafted Polymer Matrices for Separation and Industrial Applications

Energy Technology Data Exchange (ETDEWEB)

Bhardwaj, Y K; Virendra, K; Goel, N K; Sarma, K S.S.; Sabharwal, S [Radiation Technology Development Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India)

2012-09-15

Grafting of acrylonitrile onto non-woven porous polypropylene fibre sheet using electron beam was carried out by post-irradiation grafting. Grafting extent of {approx}125% was achieved. The grafted nitrile groups were amidoximated and studied for uranium uptake from sea water and heavy metal ions (Co{sup 2+}, Ni{sup 2+}, Mn{sup 2+}, and Cd{sup 2+}) from aqueous solutions. Adsorption and elution of adsorbed ions in suitable eluents was studied. The grafting process was upgraded to pilot scale to obtain 1x1 m{sup 2} sheets. Mutual radiation grafting technique was used for grafting of vinylbenzyltrimethyl ammonium chloride, [2- (methacryloyloxy)ethyl] trimethylammonium chloride and [2-(acryloyloxyethyl)]trimethylammonium chloride onto cotton cellulose substrate. The grafted matrices showed significantly higher water uptake and good water retention properties. The antibacterial efficacy of the grafted products was found to be a function of extent of grafting and the type of bacteria (Escherichia coli, Pseudomonas flourescens, Staphylococcus aureus and Bacillus cereus). PVBT-g-cotton was studied for its protein adsorption behaviour in continuous column process using Bovine serum albumin (BSA) as a model protein. Mutual radiation grafting technique was used to graft acrylic acid on micrometer thick micro-porous polypropylene membrane. Contact angle measurement studies showed that initial grafting as well as radiation treatment of poly(propylene) in aqueous medium and in presence of Mohr's salt enhances its affinity towards the grafting solution. The enhancement in the polar component of surface energy of treated polypropylene membrane is the primary cause of grafting enhancement. The membranes grafted to an extent of {approx}20% were found to perform comparably with the battery separator presently being used by battery industry. Acrylic acid was grafted to Teflon scrap by mutual radiation grafting technique. The grafting extent decreased with increasing dose rate and

Complications following linear accelerator based stereotactic radiation for cerebral arteriovenous malformations

DEFF Research Database (Denmark)

Skjøth-Rasmussen, Jane; Roed, Henrik; Ohlhues, Lars

2010-01-01

Primarily, gamma knife centers are predominant in publishing results on arteriovenous malformations (AVM) treatments including reports on risk profile. However, many patients are treated using a linear accelerator-most of these at smaller centers. Because this setting is different from a large...... gamma knife center, the risk profile at Linac departments could be different from the reported experience. Prescribed radiation doses are dependent on AVM volume. This study details results from a medium sized Linac department center focusing on risk profiles....

Stereotactic helium-ion radiosurgery for the treatment of intracranial arteriovenous malformations

International Nuclear Information System (INIS)

Fabrikant, J.I.; Levy, R.P.; Frankel, K.A.; Phillips, M.H.; Lyman, J.T.; Chuang, F.Y.S.; Steinberg, G.K.; Marks, M.P.

1989-12-01

One of the more challenging problems of vascular neurosurgery is the management of surgically-inaccessible arteriovenous malformations (AVMs) of the brain. At Lawrence Berkeley Laboratory, we have developed the method of stereotactic heavy-charged-particle (helium-ion) Bragg peak radiosurgery for treatment of inoperable intracranial AVMs in over 300 patients since 1980 [Fabrikant et al. 1989, Fabrikant et al. 1985, Levy et al. 1989]. This report describes patient selection, treatment method, clinical and neuroradiologic results and complications encountered. 4 refs

A grafting from approach to graft polystyrene chains at the surface of graphene nanolayers by RAFT polymerization: Various graft densities from hydroxyl groups

Energy Technology Data Exchange (ETDEWEB)

Roghani-Mamaqani, Hossein, E-mail: r.mamaghani@sut.ac.ir [Department of Polymer Engineering, Sahand University of Technology, PO Box 51335-1996, Tabriz (Iran, Islamic Republic of); Khezri, Khezrollah [School of Chemistry, University College of Science, University of Tehran, PO Box 14155-6455, Tehran (Iran, Islamic Republic of)

2016-01-01

Graphical abstract: (3-Aminopropyl) triethoxysilane was grafted at the surface of GO in low and high different graft densities to yield GOHAL and GOHAH, respectively. Subsequently, 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (RA) was attached at the surface of GOHAL and GOHAH by an amidation reaction to yield GOHRL and GOHRH, respectively. Then, GOHRL and GOHRH were used in grafting from RAFT polymerization of styrene. - Highlights: • A RAFT agent grafted GO was used in grafting from RAFT polymerization of styrene. • The efficiency of RAFT agent attachment at the surface of GO is 41.12% for high density sample. • Polystyrene molecular weight is decreased by the addition of graphene content and also graft density of RAFT agent. - Abstract: (3-Aminopropyl) triethoxysilane was grafted at the surface of GO in low and high different graft densities to yield GOHAL and GOHAH, respectively. Subsequently, 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (RA) was attached at the surface of GOHAL and GOHAH by an amidation reaction to yield GOHRL and GOHRH, respectively. Then, GOHRL and GOHRH were used in grafting from RAFT polymerization of styrene. Grafting of APTES and RA was approved by Fourier transform infrared spectroscopy, X-ray photo electron spectroscopy, and Raman spectroscopy. Expansion of graphene interlayer by oxidation and functionalization processes was evaluated by X-ray diffraction. Conversion values of styrene were calculated using gas chromatography. Molecular weight and PDI values of attached polystyrene (PS) chains were studied by size exclusion chromatography. Thermogravimetric analysis was also used to investigate the degradation temperatures, char contents, and graft contents of modifiers and PS chains. GOHRH and GOHRL reach to char content of 55.3 and 45.2% at 600 °C, which shows that weight ratio of modifier (APTES and RA moieties) is 15.3 and 5.2%, respectively. Scanning and transmission electron microscopies show that

Neuropeptide Treatment with Cerebrolysin Enhances the Survival of Grafted Neural Stem Cell in an α-Synuclein Transgenic Model of Parkinson's Disease

Directory of Open Access Journals (Sweden)

Edward Rockenstein

2015-01-01

Full Text Available Neuronal stem cell (NSC grafts have been investigated as a potential neuro-restorative therapy in Parkinson's disease (PD but their use is compromised by the death of grafted cells. We investigated the use of Cerebrolysin (CBL, a neurotrophic peptide mixture, as an adjunct to NSC therapy in the α-synuclein (α-syn transgenic (tg model of PD. In vehicle-treated α-syn tg mice, there was decreased survival of NSCs. In contrast, CBL treatment enhanced the survival of NSCs in α-syn tg groups and ameliorated behavioral deficits. The grafted NSCs showed lower levels of terminal deoxynucleotidyl transferase dUTP nick end labeling positive cells in the CBL-treated mice when compared with vehicle-treated α-syn tg mice. No evidence of tumor growth was detected. Levels of α-syn were similar in the vehicle in CBL-treated tg mice. In conclusion, CBL treatment might be a potential adjuvant for therapeutic NSC grafting in PD.

Spontaneous regression of brain arteriovenous malformations--a clinical study and a systematic review of the literature

NARCIS (Netherlands)

Buis, Dennis R.; van den Berg, René; Lycklama, Geert; van der Worp, H. Bart; Dirven, Clemens M. F.; Vandertop, W. Peter

2004-01-01

OBJECTIVE AND IMPORTANCE: Complete spontaneous obliteration of a brain arteriovenous malformation (AVM) is a rare event, with 67 angiographically proven cases in the world literature. We present a new case and a systematic literature review to determine possible mechanisms underlying this unusual

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.

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.

The causes and the nursing interventions of the complications due to repeated embolization therapy for huge cerebral arteriovenous malformations

International Nuclear Information System (INIS)

Sun Lingfang; Sun Ge

2010-01-01

Objective: To investigate the causes of the complications occurred after repeated embolization therapy for huge cerebral arteriovenous malformations and to discuss their nursing interventions. Methods: A total of 54 embolization procedures were performed in 17 patients with huge cerebral arteriovenous malformations. The clinical data were retrospectively analyzed. The causes of complications were carefully examined and the preventive measures were discussed. The prompt and necessary nursing interventions were formulated in order to prevent the complications or serious consequences. Results: Among the total 17 patients, one patient gave up the treatment because of the cerebral hemorrhage which occurred two months after receiving 3 times of embolization therapy. One patient experienced cerebral vascular spasm during the procedure, which was relieved after antispasmodic medication and no neurological deficit was left behind. Two patients developed transient dizziness and headache, which were alleviated spontaneously. One patient presented with nervousness, fear and irritability, which made him hard to cooperate with the operation and the basis intravenous anesthesia was employed. No complications occurred in the remaining cases. Conclusion: The predictive nursing interventions for the prevention of complications are very important for obtaining a successful repeated embolization therapy for huge cerebral arteriovenous malformations, which will ensure that the patients can get the best treatment and the complications can be avoided. (authors)

Recipient bone marrow-derived stromal cells prolong graft survival in a rat hind limb allotransplantation model.

Science.gov (United States)

Ikeguchi, Ryosuke; Kakinoki, Ryosuke; Ohta, Souichi; Oda, Hiroki; Yurie, Hirofumi; Kaizawa, Yukitoshi; Mitsui, Hiroto; Aoyama, Tomoki; Toguchida, Junya; Matsuda, Shuichi

2017-09-01

Recent studies have indicated that bone marrow-derived stromal cells (BMSCs) have immunomodulatory properties that suppress the T cell responses that cause graft rejection. The purpose of this study is to evaluate the effect of recipient BMSCs intravenous infusion for immunomodulation in a rat vascularized composite allotransplantation model. A total of nine Wistar (WIS) rats and thirty Lewis (LEW) rats were used. BMSCs were harvested from three LEW rats. Twenty-four LEW rats were used as recipients and divided randomly into four groups: BMSC group, FK group, UT group, and Iso group. In the BMSC group, orthotopic rat hind limb transplantation was performed between WIS donor and LEW recipient rats. Recipient rats were injected intravenously with 2 × 10 6 recipient BMSCs on day 6, and with 0.2 mg/kg/day tacrolimus administered over 7 days (n = 6). In the FK group, recipient rats were treated with tacrolimus alone (n = 6). Rats in the UT group received no immunosuppressive treatment (n = 6). In the Iso group, transplantation was performed from three LEW donor rats to six LEW recipient rats without any immunosuppressive treatment (n = 6). Graft survival was assessed by daily inspection and histology. The immunological reactions of recipients were also evaluated. The graft survival of recipient rats in the BMSC group (24.5 days) was significantly prolonged in comparison with that of the FK group (18 days) (P Recipient rats in the BMSC group had significantly reduced serum IFN-γ cytokine levels (1.571 ± 0.779 pg/ml) in comparison with that of the FK group (7.059 ± 1.522 pg/ml) (P = .001). In in vitro study, BMSCs induce T cell hyporesponsiveness in a mixed lymphocyte reaction. BMSCs induce T cell hyporesponsiveness and prolong graft survival in the rat vascularized composite allotransplantation model. BMSCs exhibit immunomodulatory properties against acute rejection that can be realized without the need for significant recipient

[A case of anterior tibial arteriovenous fistula after closed fracture of the leg].

Science.gov (United States)

Touzard, R C

1975-01-01

This case permits one to emphasize the great rareness of arteriovenous fistula after closed fractures of the shaft of the tibia. Fistulas in this anterior tibial position are remarkably latent, cause no symptoms below the fistula nor symptoms of heart failure. Treatment by several ligatures, permitted this patient to return to work 15 days after operation without any further treatment. The patient no longer has any symptoms.

Determination of the distribution of graft yields following a radiation-induced graft copolymerization

International Nuclear Information System (INIS)

Schipschack, K.; Wagner, H.; Sawtschenko, L.

1976-01-01

In the radiation-induced graft copolymerization on solid initial polymers a distribution of graft yields takes place along the cross-sections of samples. Methods for determining this distribution, which are described in the literature, are reviewed. In our own investigations boards made of ethylene-vinyl acetate copolymers and grafted with vinyl chloride were used. Distributions of the grafted component obtained by infrared analysis of microtome cuts parallel to the surface are partly rather inhomogeneous, and are interpreted as dependent on the experimental parameters. (author)

Study on grafting glycidyl methacrylate onto HDPE membranes by pre-irradiation graft copolymerization

International Nuclear Information System (INIS)

Tong Long; Zu Jianhua; Liu Xinwen; Sun Guisheng; Yu Chunhui

2006-01-01

Glycidyl methacrylate (GMA) was grafted onto HDPE membranes by pre-irradiation method with 1.8 MeV E-beam and a kind of membranes having reactive epoxy groups was successfully synthesized. Effects of monomer concentration, reaction temperature and time and irradiation dose on the grafting yield were studied. Composition, thermo-property and surface morphology of the grafted membranes were studied by FTIR, DSC and Tapping-mode AFM, respectively. The FTIR measurements proved the synthesized copolymer is HDPE-g-GMA. The DSC results indicated the grafted HDPE's melting temperature (T m ) and heat of fusion (ΔH f ( HDPE) ) which was reduced with increasing grafting yield. The AFM images indicated that surface of the HDPE-g-GMA membranes was rougher than the virgin HDPE. (authors)

EFFECT OF DEXTRAN-graft-POLYACRYLAMIDE INTERNAL STRUCTURE ON FLOCCULATION PROCESS PARAMETERS

International Nuclear Information System (INIS)

Bezugla, T.; Kutsevol, N.; Shyichuk, A.; Ziolkowska, D.

2008-01-01

Dextran-graft-Polyacrylamide copolymers (D-g-PAA) of brush-like architecture were tested as flocculation aids in the model kaolin suspensions. Due to expanded conformation the D-g-PAA copolymers are more effective flocculants than individual PAA with close molecular mass. The internal structure of D-g-PAA copolymers which is determined by number and length of grafted PAA chains, the distance between grafts, etc., has the significant influence on flocculation behavior of such polymers

Robot-Assisted Antegrade In-Situ Fenestrated Stent Grafting

International Nuclear Information System (INIS)

Riga, Celia V.; Bicknell, Colin D.; Wallace, Daniel; Hamady, Mohamad; Cheshire, Nicholas

2009-01-01

To determine the technical feasibility of a novel approach of in-situ fenestration of aortic stent grafts by using a remotely controlled robotic steerable catheter system in the porcine model. A 65-kg pig underwent robot-assisted bilateral antegrade in-situ renal fenestration of an abdominal aortic stent graft with subsequent successful deployment of a bare metal stent into the right renal artery. A 16-mm iliac extension covered stent served as the porcine aortic endograft. Under fluoroscopic guidance, the graft was punctured with a 20-G customized diathermy needle that was introduced and kept in place by the robotic arm. The needle was exchanged for a 4 x 20 mm cutting balloon before successful deployment of the renal stent. Robot-assisted antegrade in-situ fenestration is technically feasible in a large mammalian model. The robotic system enables precise manipulation, stable positioning, and minimum instrumentation of the aorta and its branches while minimizing radiation exposure.

Ischaemic strokes in patients with pulmonary arteriovenous malformations and hereditary hemorrhagic telangiectasia: associations with iron deficiency and platelets.

Directory of Open Access Journals (Sweden)

Claire L Shovlin

Full Text Available BACKGROUND: Pulmonary first pass filtration of particles marginally exceeding ∼7 µm (the size of a red blood cell is used routinely in diagnostics, and allows cellular aggregates forming or entering the circulation in the preceding cardiac cycle to lodge safely in pulmonary capillaries/arterioles. Pulmonary arteriovenous malformations compromise capillary bed filtration, and are commonly associated with ischaemic stroke. Cohorts with CT-scan evident malformations associated with the highest contrast echocardiographic shunt grades are known to be at higher stroke risk. Our goal was to identify within this broad grouping, which patients were at higher risk of stroke. METHODOLOGY: 497 consecutive patients with CT-proven pulmonary arteriovenous malformations due to hereditary haemorrhagic telangiectasia were studied. Relationships with radiologically-confirmed clinical ischaemic stroke were examined using logistic regression, receiver operating characteristic analyses, and platelet studies. PRINCIPAL FINDINGS: Sixty-one individuals (12.3% had acute, non-iatrogenic ischaemic clinical strokes at a median age of 52 (IQR 41-63 years. In crude and age-adjusted logistic regression, stroke risk was associated not with venous thromboemboli or conventional neurovascular risk factors, but with low serum iron (adjusted odds ratio 0.96 [95% confidence intervals 0.92, 1.00], and more weakly with low oxygen saturations reflecting a larger right-to-left shunt (adjusted OR 0.96 [0.92, 1.01]. For the same pulmonary arteriovenous malformations, the stroke risk would approximately double with serum iron 6 µmol/L compared to mid-normal range (7-27 µmol/L. Platelet studies confirmed overlooked data that iron deficiency is associated with exuberant platelet aggregation to serotonin (5HT, correcting following iron treatment. By MANOVA, adjusting for participant and 5HT, iron or ferritin explained 14% of the variance in log-transformed aggregation-rate (p = 0

Skin graft - slideshow

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... 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 ...

Tissue Responses to Stent Grafts with Endo-Exo-Skeleton for Saccular Abdominal Aortic Aneurysms in a Canine Model

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Kim, Il Young; Chung, Jin Wook; Kim, Hyo Cheol [Dept. of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Clinical Research Institute, Seoul (Korea, Republic of); Choi, Young Ho; So Young Ho [Dept. of Radiology, Seoul National University Boramae Hospital, Seoul (Korea, Republic of); Kim, Hyun Beom [Dept. of Radiology, National Cancer Center, Goyang (Korea, Republic of); Min, Seung Kee [Dept. of Surgery, Seoul National University College of Medicine, Seoul (Korea, Republic of); Park, Jae Hyung [Dept. of Radiology, Gachon University Gil Medical Center, Incheon (Korea, Republic of)

2014-10-15

We evaluated the effect of close contact between the stent and the graft on the induction of endothelial covering on the stent graft placed over an aneurysm. Saccular abdominal aortic aneurysms were made with Dacron patch in eight dogs. The stent graft consisted of an inner stent, a expanded polytetrafluoroethylene graft, and an outer stent. After sacrificing the animals, the aortas with an embedded stent graft were excised. The aortas were inspected grossly and evaluated microscopically. The animals were sacrificed at two (n = 3), six (n = 3), and eight months (n = 2) after endovascular repair. In two dogs, the aortic lumen was occluded at two months after the placement. On gross inspection of specimens from the other six dogs with a patent aortic lumen, stent grafts placed over the normal aortic wall were covered by glossy white neointima, whereas, stent grafts placed over the aneurysmal aortic wall were covered by brownish neointima. On microscopic inspection, stent grafts placed over the normal aortic wall were covered by thin neointima (0.27 ± 0.05 mm, mean ± standard deviation) with an endothelial layer, and stent grafts placed over the aneurysmal aortic wall were covered by thick neointima (0.62 ± 0.17 mm) without any endothelial lining. Transgraft cell migration at the normal aortic wall was more active than that at the aneurysmal aortic wall. Close contact between the stent and the graft, which was achieved with stent grafts with endo-exo-skeleton, could not enhance endothelial covering on the stent graft placed over the aneurysms.

Lycopene and flesh colour differences in grafted and non-grafted watermelon

OpenAIRE

Fekete D.; Stéger-Máté M.; Bőhm V.; Balázs G.; Kappel N.

2015-01-01

The experiment was carried out in three regions in Hungary (Jászszentandrás, Cece, Újkígyós) in 2013 to determine the fruit quality of grafted watermelon (Citrullus lanatus Thunb.). The “RX 467” seedless watermelon variety was grafted on two commercial rootstocks “FR STRONG” [Lagenaria siceraria (Mol.) Standl.] and “RS 841” (Cucurbita maxima Duchesne × Cucurbita moschata Duchesne). The lycopene and flesh colours are important quality characteristics even of the selfrooted and grafted watermel...

A new grafting technique for tympanoplasty: tympanoplasty with a boomerang-shaped chondroperichondrial graft (TwBSCPG).

Science.gov (United States)

Dündar, Rıza; Soy, Fatih Kemal; Kulduk, Erkan; Muluk, Nuray Bayar; Cingi, Cemal

2014-10-01

The aim of this study was to introduce a new grafting technique in tympanoplasty that involves use of a boomerang-shaped chondroperichondrial graft (BSCPG). The anatomical and functional results were evaluated. A new tympanoplasty with boomerang-shaped chondroperichondrial graft (TwBSCPG) technique was used in 99 chronic otitis media patients with central or marginal perforation of the tympanic membrane and a normal middle ear mucosa. All 99 patients received chondroperichondrial cartilage grafts with a boomerang-shaped cartilage island left at the anterior and inferior parts. Postoperative follow-ups were conducted at months 1, 6, and 12. Preoperative and postoperative audiological examinations were performed and air-bone gaps were calculated according to the pure-tone averages (PTAs) of the patients. In the preoperative period, most (83.8%) air-bone gaps were ≥ 16 dB; after operating using the TwBSCPG technique, the air-bone gaps decreased to 0-10 dB in most patients (77.8%). In the TwBSCPG patients, the mean preoperative air-bone gap was 22.02 ± 6.74 dB SPL. Postoperatively, the mean postoperative air-bone gap was 8.70 ± 5.74 dB SPL. The TwBSCPG technique therefore decreased the postoperative air-bone gap compared to that preoperatively (p = 0.000, z = -8.645). At the 1-month follow-up, there were six graft perforations and one graft retraction. At the 6-month follow-up, there were nine graft perforations and three graft retractions. At 12 months, there were seven graft perforations and four graft retractions. During the first year after the boomerang tympanoplasty surgery, graft lateralization was not detected in any patient. Retractions were grade 1 according to the Sade classification and were localized to the postero-superior quadrant of the tympanic membrane. The TwBSCPG technique has benefits with respect to postoperative anatomical and audiological results. It prevents perforation of the tympanic membrane at the anterior quadrant and avoids graft

Angiographic Evaluation of Carotid Artery Grafting with Prefabricated Small-Diameter, Small-Intestinal Submucosa Grafts in Sheep

International Nuclear Information System (INIS)

Pavcnik, Dusan; Obermiller, Josef; Uchida, Barry T.; Van Alstine, William; Edwards, James M.; Landry, Gregory J.; Kaufman, John A.; Keller, Frederick S.; Roesch, Josef

2009-01-01

The purpose of this study was to report the longitudinal angiographic evaluation of prefabricated lyophilized small-intestinal submucosa (SIS) grafts placed in ovine carotid arteries and to demonstrate a variety of complications that developed. A total of 24 grafts, 10 cm long and 6 mm in diameter, were placed surgically as interposition grafts. Graft patency at 1 week was evaluated by Doppler ultrasound, and angiography was used for follow-up at 1 month and at 3 to 4 months. A 90% patency rate was found at 1 week, 65% at 1 month, and 30% at 3 to 4 months. On the patent grafts, angiography demonstrated a variety of changes, such as anastomotic stenoses, graft diffuse dilations and dissections, and aneurysm formation. These findings have not been previously demonstrated angiographically by other investigators reporting results with small-diameter vessel grafts made from fresh small-intestinal submucosa (SIS). The complications found were partially related to the graft construction from four SIS layers. Detailed longitudinal angiographic study should become an essential part of any future evaluation of small-vessel SIS grafting.

Micro-Computed Tomography Evaluation of Human Fat Grafts in Nude Mice

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Chung, Michael T.; Hyun, Jeong S.; Lo, David D.; Montoro, Daniel T.; Hasegawa, Masakazu; Levi, Benjamin; Januszyk, Michael; Longaker, Michael T.

2013-01-01

Background Although autologous fat grafting has revolutionized the field of soft tissue reconstruction and augmentation, long-term maintenance of fat grafts is unpredictable. Recent studies have reported survival rates of fat grafts to vary anywhere between 10% and 80% over time. The present study evaluated the long-term viability of human fat grafts in a murine model using a novel imaging technique allowing for in vivo volumetric analysis. Methods Human fat grafts were prepared from lipoaspirate samples using the Coleman technique. Fat was injected subcutaneously into the scalp of 10 adult Crl:NU-Foxn1nu CD-1 male mice. Micro-computed tomography (CT) was performed immediately following injection and then weekly thereafter. Fat volume was rendered by reconstructing a three-dimensional (3D) surface through cubic-spline interpolation. Specimens were also harvested at various time points and sections were prepared and stained with hematoxylin and eosin (H&E), for macrophages using CD68 and for the cannabinoid receptor 1 (CB1). Finally, samples were explanted at 8- and 12-week time points to validate calculated micro-CT volumes. Results Weekly CT scanning demonstrated progressive volume loss over the time course. However, volumetric analysis at the 8- and 12-week time points stabilized, showing an average of 62.2% and 60.9% survival, respectively. Gross analysis showed the fat graft to be healthy and vascularized. H&E analysis and staining for CD68 showed minimal inflammatory reaction with viable adipocytes. Immunohistochemical staining with anti-human CB1 antibodies confirmed human origin of the adipocytes. Conclusions Studies assessing the fate of autologous fat grafts in animals have focused on nonimaging modalities, including histological and biochemical analyses, which require euthanasia of the animals. In this study, we have demonstrated the ability to employ micro-CT for 3D reconstruction and volumetric analysis of human fat grafts in a mouse model. Importantly

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

Management of intracranial arteriovenous malformations

International Nuclear Information System (INIS)

Miyamoto, Susumu; Takahashi, Jun C.

2008-01-01

Intracranial arteriovenous malformations (AVMs) are congenital lesions that can cause serious neurological deficits or even death. They can manifest as intracranial hemorrhage, epileptic seizure, or other symptoms such as headache or tinnitus. They are detected by computed tomography or magnetic resonance imaging. Recently there have been significant developments in the management of AVMs. In this paper, the authors represent an overview of the epidemiology of AVMs and the existing treatment strategies. AVMs are ideally excised by standard microsurgical techniques. The grading scale which was proposed by Spetzler and Martin is widely used to estimate the risk of direct surgery. Stereotactic radiosurgery such as that using a gamma knife is very useful for small lesions located in eloquent areas. Technological advances in endovascular surgery have provided new alternatives in the treatment of AVMs. Currently indications for embolization can be divided into presurgical embolization in large AVMs to occlude deep arterial feeding vessels and embolization before stereotactic radiosurgery to reduce the size of the nidus. Palliative embolization can be also applied for patients with large, inoperable AVMs who are suffering from progressive neurological deficits secondary to venous hypertension and/or arterial steal phenomenon. (author)

Management of intracranial arteriovenous malformations

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Miyamoto, Susumu; Takahashi, Jun C [National Cardiovascular Center, Suita, Osaka (Japan)

2008-10-15

Intracranial arteriovenous malformations (AVMs) are congenital lesions that can cause serious neurological deficits or even death. They can manifest as intracranial hemorrhage, epileptic seizure, or other symptoms such as headache or tinnitus. They are detected by computed tomography or magnetic resonance imaging. Recently there have been significant developments in the management of AVMs. In this paper, the authors represent an overview of the epidemiology of AVMs and the existing treatment strategies. AVMs are ideally excised by standard microsurgical techniques. The grading scale which was proposed by Spetzler and Martin is widely used to estimate the risk of direct surgery. Stereotactic radiosurgery such as that using a gamma knife is very useful for small lesions located in eloquent areas. Technological advances in endovascular surgery have provided new alternatives in the treatment of AVMs. Currently indications for embolization can be divided into presurgical embolization in large AVMs to occlude deep arterial feeding vessels and embolization before stereotactic radiosurgery to reduce the size of the nidus. Palliative embolization can be also applied for patients with large, inoperable AVMs who are suffering from progressive neurological deficits secondary to venous hypertension and/or arterial steal phenomenon. (author)

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

International Nuclear Information System (INIS)

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

2008-01-01

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

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

Directory of Open Access Journals (Sweden)

Ying Guan

2016-08-01

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

An Arteriovenous Fistula Between the Internal Mammary Artery and the Pulmonary Vein Following Blunt Chest Trauma

International Nuclear Information System (INIS)

Ito, T.; Sakamoto, Toshihisa; Norio, Hirofumi; Kaji, Tatsumi; Okada, Yoshiaki

2005-01-01

A 67-year-old man suffered a traffic accident and was transferred to an emergency hospital close to the scene. He was diagnosed to have bilateral pneumohemothorax with a lung contusion, an anterior fracture dislocation of the C6-vertebra and a cervical cord injury at the level of C7. On the 48th day, massive hemoptysis was suddenly recognized. He was transferred in a state of shock to our hospital to undergo hemostasis for the bleeding. On the day of admission, a selective arteriogram showed extravasation from the left bronchial artery, for which embolization was carried out using Gelfoam. In spite of this treatment, his hemoptysis continued. On the next day, a selective left internal mammary arteriogram showed an arteriovenous fistula between the left internal mammary artery and the left pulmonary vein without any apparent extravasation. The arteriovenous fistula was successfully embolized using platinum fiber coils. The patient no longer demonstrated any hemoptysis after embolization

Automatic definition of prescription isodose for stereotactic irradiations of arteriovenous malformations

International Nuclear Information System (INIS)

Dejean, C.; Lefkopoulos, D.; Foulquier, J.N.; Schlienger, M.; Touboul, E.

2001-01-01

To evaluate dosimetric consequences generated by the automatic definition based on lesion coverage of prescription isodose. A clinical series of 124 arteriovenous malformations was analysed. Plan quality was quantified by the standard deviation of the differential dose volume histogram calculated in the lesion. We define two quantitative protocols based on lesion coverage for the automatic definition of prescription isodose using a volumetric definition of coverage (90% of lesion volume), and an isodose-based definition proposed) by RTOG (prescription isodose equals minimum isodose in the lesion divided by 0.9). We have evaluated the plans obtained for these two protocols, calculating several dose-volume indices. These indices are presented as a function of dose-volume histogram standard deviation in order to quantify the consequences of their variations for this representative series of plans. The margin our team tolerates is such that the sum of under-dosed lesion and overdosed healthy tissues factors remains lower than one. Protocol based on volumetric coverage gives results situated within this margin. Protocol based on RTOG definition produces conformation indices that could be greater than 1. The absolute dose would be decided taking into account examined dose-volume indices and clinical data. A protocol for automatic definition of prescription isodose using volumetric lesion coverage seems to be more judiciously adapted to arteriovenous malformation conformal plans in stereotactic conditions because of variations observed in the overdosage of healthy tissues. (authors)

Depth of the graft bed influences split-skin graft contraction.

NARCIS (Netherlands)

Mensik, I.; Lamme, E.N.; Brychta, P.

2003-01-01

Contraction of a split-thickness skin graft used for coverage of large defects remains a great problem in plastic, burn and reconstructive surgery. In this study we evaluated healing of split-thickness skin grafts transplanted in wounds on the subcutaneous fat and muscle fascia in pigs. Four young

Secondary necrosis: the radiosurgery in the cerebral arteriovenous malformations. CT and MR aspects

International Nuclear Information System (INIS)

Pina, J.I.; Medrano, J.; Benito, J.L. de; Sierra, R. la; Feijoo, R.; Villavieja, J.L.

1995-01-01

The Ct and MR findings are presented for two patients previously diagnosed as having cerebral arteriovenous malformations (AVM), treated by means of stereotaxic radiosurgery. The study of their course following corticosteroid therapy is also reported. The diagnosis was based on changes in the MR signal and density on CT and on their late onset, and was confirmed by puncture. The good clinical and radiological course is discussed. (Author) 10 refs

Radiation-induced grafting of sweet sorghum stalk for copper(II) removal from aqueous solution

International Nuclear Information System (INIS)

Dong, Jing; Hu, Jun; Wang, Jianlong

2013-01-01

Highlights: • Radiation-induced grafting was used to modify the stalk. • Cellulose, hemicellulose and lignin participated in grafting reaction. • Both the structure and composition of stalk had influence on grafting. • The sorption capacity of the grafted stalk increased about five times. -- Abstract: The influence of main components (cellulose, hemicellulose and lignin) of the sweet sorghum stalk on radiation-induced grafting reaction and adsorption of copper from aqueous solution was investigated. Sweet sorghum stalk was grafted with acrylic acid induced by γ-irradiation. The results showed that the grafted stalk contained 1.6 mmol/g carboxyl groups, and its maximal adsorption capacity was 13.32 mg/g. The cellulose, hemicellulose and lignin of the raw materials were confirmed to involve in grafting reaction through comparing the grafting yield and the structure of the grafted materials. Both the structure and the composition of the sweet sorghum stalk had influence on the grafting reaction and adsorption capacity. The adsorption capacity of the grafted sweet sorghum stalk increased about five times, and the adsorption isotherm of the grafted materials conformed to the Langmuir model. The main mechanism for copper adsorption involved in ion exchange

Bone scintigraphy in evaluating the viability of composite bone grafts revascularized by microvascular anastomoses, conventional autogenous bone grafts, and free non-revascularized periosteal grafts

International Nuclear Information System (INIS)

Berggren, A.; Weiland, A.J.; Ostrup, L.T.

1982-01-01

Researchers studied the value of bone scintigraphy in the assessment of anastomotic patency and bone-cell viability in free bone grafts revascularized by microvascular anastomoses in twenty-seven dogs. The dogs were divided into three different groups, and scintigraphy was carried out using technetium-labeled methylene diphosphonate in composite bone grafts revascularized by microvascular anastomoses, conventional autogenous bone grafts, and periosteal grafts placed in different recipient beds. The viability of the grafts were evaluated by histological examination and fluorescence microscopy after triple labeling with oxytetracycline on the first postoperative day, alizarin complexone on the fourth postoperative day, and DCAF on the eleventh postoperative day. A positive scintiscan within the first week following surgery indicated patent microvascular anastomoses, and histological study and fluorescence microscopy confirmed that bone throughout the graft was viable. A positive scintiscan one week after surgery or later does not necessarily indicate microvascular patency or bone-cell survival, because new bone formed by creeping substitution on the surface of a dead bone graft can result in this finding

Acute Tetraparesis with Respiratory Failure after Steroid Administration in a Patient with a Dural Arteriovenous Fistula at the Craniocervical Junction

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Takahashi, Hisashi; Ueshima, Taiki; Goto, Daiki; Kimura, Tadashi; Yuki, Natsuko; Inoue, Yasuo; Yoshioka, Akira

2017-01-01

A 63-year-old man developed vomiting, paraparesis, dysuria, bulbar palsy, and orthostatic hypotension over a period of 5 months. Neuroradiological examinations showed a swollen lower brainstem with a dural arteriovenous fistula at the craniocervical junction (DAVF-CCJ). A steroid was administered intravenously in the hospital to relieve brainstem edema. A few hours later, however, the patient developed acute tetraparesis with respiratory failure. Recently, there have been several reports describing the acute worsening of paraparesis in patients with a spinal dural arteriovenous fistula after steroid treatment. In addition to these reports, the present case suggests the risk of administering steroids to patients with DAVF-CCJ, especially those with brainstem dysfunction. PMID:29225249

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

Similar Outcomes in Diabetes Patients After Coronary Artery Bypass Grafting With Single Internal Thoracic Artery Plus Radial Artery Grafting and Bilateral Internal Thoracic Artery Grafting.

Science.gov (United States)

Raza, Sajjad; Blackstone, Eugene H; Houghtaling, Penny L; Koprivanac, Marijan; Ravichandren, Kirthi; Javadikasgari, Hoda; Bakaeen, Faisal G; Svensson, Lars G; Sabik, Joseph F

2017-12-01

The purpose of this study was to determine in patients with diabetes mellitus whether single internal thoracic artery (SITA) plus radial artery (RA) grafting yields outcomes similar to those of bilateral internal thoracic artery (BITA) grafting. From January 1994 to January 2011, 1,325 diabetic patients underwent primary isolated coronary artery bypass graft surgery with either (1) SITA plus RA with or without saphenous vein (SV) grafts (n = 965) or (2) BITA with or without SV grafts (n = 360); an internal thoracic artery was used in all patients to graft the left anterior descending coronary artery. Endpoints were in-hospital outcomes and time-related mortality. Median follow-up was 7.4 years, with a total follow-up of 9,162 patient-years. Propensity score matching was performed to identify 282 well-matched pairs for adjusted comparisons. Unadjusted in-hospital mortality was 0.52% for SITA plus RA with or without SV grafts and 0.28% for BITA with or without SV grafts, and prevalence of deep sternal wound infection was 3.2% and 1.7%, respectively. Unadjusted survival at 1, 5, 10, and 14 years was 97%, 88%, 68%, and 51% for SITA plus RA with or without SV grafts, and 97%, 95%, 80%, and 66% for BITA with or without SV grafts, respectively. Among propensity-matched patients, in-hospital mortality (0.35% versus 0.35%) and prevalence of deep sternal wound infection (1.4% versus 1.4%) were similar (p > 0.9) in the two groups, as was 1-, 5-, 10-, and 14-year survival: 97%, 90%, 70%, and 58% for SITA plus RA with or without SV grafting versus 97%, 93%, 79%, and 64% for BITA with or without SV grafting, respectively (early p = 0.8, late p = 0.2). For diabetic patients, SITA plus RA with or without SV grafting and BITA with or without SV grafting yield similar in-hospital outcomes and long-term survival after coronary artery bypass graft surgery. Therefore, both SITA plus RA and BITA plus SV grafting should be considered for these patients. Copyright © 2017 The Society

Four-dimensional computed tomography angiographic evaluation of cranial dural arteriovenous fistula before and after embolization

International Nuclear Information System (INIS)

Tian, Bing; Xu, Bing; Lu, Jianping; Liu, Qi; Wang, Li; Wang, Minjie

2015-01-01

Highlights: • 4D CTA showed excellent agreement with DSA with regard to identification of feeding arteries and drainage veins. • The most important finding was 4D CTA in determining the impact of DAVF treatment with transarterial embolization. • 4D CTA provides images similar to those obtained with DSA both before and after treatment. - Abstract: Purpose: This study aimed to evaluate the usefulness of four-dimensional CTA before and after embolization treatment with ONYX-18 in eleven patients with cranial dural arteriovenous fistulas, and to compare the results with those of the reference standard DSA. Patients and Methods: Eleven patients with cranial dural arteriovenous fistulas detected on DSA underwent transarterial embolization with ONYX-18. Four-dimensional CTA was performed an average of 2 days before and 4 days after DSA. Four-dimensional CTA and DSA images were reviewed by two neuroradiologists for identification of feeding arteries and drainage veins and for determining treatment effects. Interobserver and intermodality agreement between four-dimensional CTA and DSA were assessed. Results: Forty-two feeding arteries were identified for 14 fistulas in the 11 patients. Of these, 36 (85.71%) were detected on four-dimensional CTA. After transarterial embolization, one patient got partly embolized, and the fistulas in the remaining 10 patients were completely occluded. The interobserver agreement for four-dimensional CTA and intermodality agreement between four-dimensional CTA and DSA were excellent (κ = 1) for shunt location, identification of drainage veins, and fistula occlusion after treatment. Conclusion: Four-dimensional CTA images are highly accurate when compared with DSA images both before and after transarterial embolization treatment. Four-dimensional CTA can be used for diagnosis as well as follow-up of cranial dural arteriovenous fistulas in clinical settings

A Rare Case of Jejunal Arterio-Venous Fistula: Treatment with Superselective Catheter Embolization with a Tracker-18 Catheter and Microcoils

International Nuclear Information System (INIS)

Sonnenschein, Martin J.; Anderson, Suzanne E.; Lourens, Steven; Triller, Juergen

2004-01-01

Arterio-venous fistulas may develop spontaneously, following trauma or infection, or be iatrogenic in nature. We present a rare case of a jejunal arterio- venous fistula in a 35-year-old man with a history of pancreatic head resection that had been performed two years previously because of chronic pancreatitis. The patient was admitted with acute upper abdominal pain, vomiting and an abdominal machinery-type bruit. The diagnosis of a jejunal arterio-venous fistula was established by MR imaging. Transfemoral angiography was performed to assess the possibility of catheter embolization. The angiographic study revealed a small aneurysm of the third jejunal artery, abnormal early filling of dilated jejunal veins and marked filling of the slightly dilated portal vein (13-14 mm). We considered the presence of segmental portal hypertension. The patient was treated with coil embolization in the same angiographic session. This case report demonstrates the importance of auscultation of the abdomen in the initial clinical examination. MR imaging and color Doppler ultrasound are excellent noninvasive tools in establishing the diagnosis. The role of interventional radiological techniques in the treatment of early portal hypertension secondary to jejunal arterio-venous fistula is discussed at a time when this condition is still asymptomatic. A review of the current literature is included

Beta irradiation inhibits neo-intimal formation in vein grafts

International Nuclear Information System (INIS)

Lang Xiaoou; Ji Shenquan; Zeng Ke; Li Jun; Liu Bingbing; Ma Wenfeng; Zhang Qiang

2002-01-01

Objective: The study was to evaluate the effect of beta irradiation on intimal proliferation response in vein grafts. Methods: An autogenous vein graft model was established in 40 rats by transplanting internal branch of jugular vein to carotid artery by end-to-end anastomosis. The vein was irradiated by 32 P before anastomosis. Four dose schedules were studied: (1) control graft (nonirradiated); (2) irradiated with 8 Gy; (3) 18 Gy; and (4) 36 Gy. The grafted veins were harvested at 2 weeks after the operation. IH (intimal hyperplasia) and SMC (smooth muscle cell) proliferation were histologically and immuno-histochemically observed and analyzed by a computer digitalising system. Results: In 18 Gy and 36 Gy-irradiated grafts compared with the control, there was a significant decrease in the average intimal thickness (P 0.05). Immunohistochemical analysis of PCNA indicated decrease of positive cells in both 18 Gy and 36 Gy groups compared with 8 Gy and the control group (P 0.05) groups, and there was also no significant difference between 8 Gy and the control group (P > 0.05). Conclusion: These preliminary results demonstrate that proper dose of beta irradiation in vein graft inhibits smooth muscle cells proliferation and neo-intimal hyperplasia in rat

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.

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

Fístula axilo-cava para hemodiálise: relato de caso Axillary arteriovenous fistula for hemodialysis: case report

Directory of Open Access Journals (Sweden)

Yosio Nagato

2009-12-01

Full Text Available Na confecção de fístula arteriovenosa (FAV para hemodiálise, condutos venosos autógenos demonstram performance superior quando comparados com material protético em relação à perviedade primária ou secundária. A prótese de politetrafluoroetileno (PTFE é reservada para casos de falência de material autógeno e é geralmente utilizada em fístulas em membros superiores. Descrevemos o caso de uma paciente de 52 anos que, após falência de acessos para hemodiálise e impossibilidade de realização de diálise peritoneal em razão de peritonite bacteriana, foi submetida à confecção de FAV entre a artéria axilar direita e a veia cava inferior com prótese de PTFE de 6 mm. O acesso foi utilizado para hemodiálise 1 mês após sua criação e permanece pérvio após 24 meses. Até o momento, não houve complicações infecciosas, sinais de insuficiência cardíaca ou síndrome de roubo em membro superior direito.With regards to the creation of an arteriovenous fistula (AV fistula for hemodialysis, autogenous venous grafts clearly show high performance when compared with prosthetic material in terms of primary or secondary patency. Polytetrafluoroethylene (PTFE grafts for the reconstruction of AV fistulae must be restricted to cases of failure of the autogenous material, which is generally used in upper limb fistulae. We describe a case of a 52-year-old patient, who, after access failure for hemodialysis and the impossibility of performing peritoneal dialysis due to bacterial peritonitis, underwent the reconstruction of an AV fistula between the right axillary artery and the cava vein using a 6-mm PTFE prosthesis. One month after surgery, this AV fistula started to be used for hemodialysis. The AV fistula remains patent 24 months after its creation. No infectious complications, cardiac insufficiency symptoms, or steal syndromes of right upper limb were detected.

Radiation chemical grafting of vinyl acetate and styrene on nitrocellulose

International Nuclear Information System (INIS)

Chapiro, A.; Foex, M.; Jendrychowska-Bonamour, A.M.

1977-01-01

Vinyl acetate and styrene were grafted onto nitrocellulose using the direct radiation grafting technique with 500 and 3000 Ci 60 Co γ sources. For vinyl acetate, the reaction proceeds homogeneously. The kinetics are dominated by degradative chain transfer to the nitrocellulose. The polymerization of vinyl acetate was examined in the presence of isoamyl nitrate, a model for nitrocellulose; the transfer constant was determined and the results are treated semi-quantitatively. For styrene, grafting occurs in a swollen film irradiated in the presence of excess monomer. The diffusion of styrene into nitrocellulose is extremely slow; methanol was added to the reaction mixture to favour diffusion which was found to obey Fick's law. The diffusion constant and activation energy of diffusion are evaluated. The grafting kinetics are controlled by monomer diffusion, accounting for the increase of dose-rate exponent with temperature. A spontaneous grafting process occurs in the absence of irradiation. It is initiated by macroradicals arising from thermal decomposition of nitrocellulose. (author)

Preparation of pre-confluent retinal cells increases graft viability in vitro and in vivo: a mouse model.

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Kevin P Kennelly

Full Text Available PURPOSE: Graft failure remains an obstacle to experimental subretinal cell transplantation. A key step is preparing a viable graft, as high levels of necrosis and apoptosis increase the risk of graft failure. Retinal grafts are commonly harvested from cell cultures. We termed the graft preparation procedure "transplant conditions" (TC. We hypothesized that culture conditions influenced graft viability, and investigated whether viability decreased following TC using a mouse retinal pigment epithelial (RPE cell line, DH01. METHODS: Cell viability was assessed by trypan blue exclusion. Levels of apoptosis and necrosis in vitro were determined by flow cytometry for annexin V and propidium iodide and Western blot analysis for the pro- and cleaved forms of caspases 3 and 7. Graft viability in vivo was established by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL and cleaved caspase 3 immunolabeling of subretinal allografts. RESULTS: Pre-confluent cultures had significantly less nonviable cells than post-confluent cultures (6.6%±0.8% vs. 13.1%±0.9%, p<0.01. Cell viability in either group was not altered significantly following TC. Caspases 3 and 7 were not altered by levels of confluence or following TC. Pre-confluent cultures had low levels of apoptosis/necrosis (5.6%±1.1% that did not increase following TC (4.8%±0.5%. However, culturing beyond confluence led to progressively increasing levels of apoptosis and necrosis (up to 16.5%±0.9%. Allografts prepared from post-confluent cultures had significantly more TUNEL-positive cells 3 hours post-operatively than grafts of pre-confluent cells (12.7%±3.1% vs. 4.5%±1.4%, p<0.001. Subretinal grafts of post-confluent cells also had significantly higher rates of cleaved caspase 3 than pre-confluent grafts (20.2%±4.3% vs. 7.8%±1.8%, p<0.001. CONCLUSION: Pre-confluent cells should be used to maximize graft cell viability.

Non- invasive in vivo analysis of a murine aortic graft using high resolution ultrasound microimaging

International Nuclear Information System (INIS)

Rowinska, Zuzanna; Zander, Simone; Zernecke, Alma; Jacobs, Michael; Langer, Stephan; Weber, Christian; Merx, Marc W.; Koeppel, Thomas A.

2012-01-01

Introduction: As yet, murine aortic grafts have merely been monitored histopathologically. The aim of our study was to examine how these grafts can be monitored in vivo and non-invasively by using high-resolution ultrasound microimaging to evaluate function and morphology. A further aim was to prove if this in vivo monitoring can be correlated to immunohistological data that indicates graft integrity. Methods: Murine infrarenal aortic isografts were orthotopically transplanted into 14 female mice (C57BL/6-Background) whereas a group of sham-operated animals (n = 10) served as controls. To assess the graft morphology and hemodynamics, we examined the mice over a post-operative period of 8 weeks with a sophisticated ultrasound system (Vevo 770, Visual Sonics). Results: The non-invasive graft monitoring was feasible in all transplanted mice. We could demonstrate a regular post-transplant graft function and morphology, such as anterior/posterior wall displacement and wall thickness. Mild alterations of anterior wall motion dynamics could only be observed at the site of distal graft anastomosis (8 weeks after grafting (transplant vs. sham mice: 0.02 mm ± 0.01 vs. 0.03 mm ± 0.01, p < 0.05). However, the integrity of the entire graft wall could be confirmed by histopathological evaluation of the grafts. Conclusions: With regard to graft patency, function and morphology, high resolution ultrasound microimaging has proven to be a valuable tool for longitudinal, non-invasive, in vivo graft monitoring in this murine aortic transplantation model. Consequently, this experimental animal model provides an excellent basis for molecular and pharmacological studies using genetically engineered mice.

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

Pulmonary arteriovenous malformation in cryptogenic liver

International Nuclear Information System (INIS)

Afzal, N.

2013-01-01

The cause in 10 - 20% cases of liver cirrhosis (LC) cannot be elucidated, and are thus termed cryptogenic. Pulmonary arteriovenous malformations (PAVMs) are relatively rare, but the most common anomaly involving the pulmonary tree. Although the rare correlation between LC and PAVM is well-known, there have been no reports of PAVMs occurring in cryptogenic LC. We report a case of PAVM that occurred in cryptogenic liver cirrhosis in a 3 years old male child. The child presented with complaints of malena, hematemesis and variceal bleed. The examination revealed a child with respiratory distress, irritability, tachycardia, clubbing and abdominal distention. He was worked up for recurrent variceal bleeding secondary to portal hypertension but the oxygen saturation during hospital stay kept deteriorating. The diagnosis of hepatopulmonary syndrome as the cause of persistent hypoxemia in the absence of other cardio-pulmonary causes was then made by enhanced echocardiogram using agitated saline. He improved significantly after liver transplantation performed abroad. At a 6 months follow-up, the child was stable with no evidence of intrapulmonary shunting on repeat echo. (author)

Endovascular treatment of intracranial arteriovenous malformations

International Nuclear Information System (INIS)

Seruga, T.

2002-01-01

Background. The aim of the study was the introduction of endovascular interventional treatment of cerebral arteriovenous malformations (AVM) with superselective embolization with cyanoacrylic polymerisation agent. Case reports. Endovascular embolization was performed in five patients with cerebral AVMs. Three of these patients were presented with intracerebral haemathomas whereas in other two patients, cerebral AVM was an incidental finding. Superselective catheterisation of AVMs was performed and acrylic glue was selectively injected into the nidus. Conclusions. Control cerebral angiography after embolization of AVM showed different results. In one patient, AVM was totally occluded after three sessions and in second case AVM was occluded in a single session. The rate of occlusion in other two cases was estimated between 70% in 80%. Both of these two patients underwent surgery. One patient is still in the process of treatment. Endovascular treatment of cerebral AVMs with superselective embolization with liquid cyanoacrilyc adhesive agent is a safe and effective alternative treatment paths next to microsurgery. Endovascular treatment in combination with radiosurgery could become the method of choice in the therapy of cerebral AVMs in the future. (author)

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.

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

Autologous nerve graft repair of different degrees of sciatic nerve defect：stress and displacement at the anastomosis in a three-dimensional finite element simulation model

Institute of Scientific and Technical Information of China (English)

Cheng-dong Piao; Kun Yang; Peng Li; Min Luo

2015-01-01

In the repair of peripheral nerve injury using autologous or synthetic nerve grafting, the mag-nitude of tensile forces at the anastomosis affects its response to physiological stress and the ultimate success of the treatment. One-dimensional stretching is commonly used to measure changes in tensile stress and strain; however, the accuracy of this simple method is limited. There-fore, in the present study, we established three-dimensional ifnite element models of sciatic nerve defects repaired by autologous nerve grafts. Using PRO E 5.0 ifnite element simulation software, we calculated the maximum stress and displacement of an anastomosis under a 5 N load in 10-, 20-, 30-, 40-mm long autologous nerve grafts. We found that maximum displacement increased with graft length, consistent with specimen force. These ifndings indicate that three-dimensional ifnite element simulation is a feasible method for analyzing stress and displacement at the anas-tomosis after autologous nerve grafting.

Autologous nerve graft repair of different degrees of sciatic nerve defect: stress and displacement at the anastomosis in a three-dimensional fnite element simulation model

Directory of Open Access Journals (Sweden)

Cheng-dong Piao

2015-01-01

Full Text Available In the repair of peripheral nerve injury using autologous or synthetic nerve grafting, the magnitude of tensile forces at the anastomosis affects its response to physiological stress and the ultimate success of the treatment. One-dimensional stretching is commonly used to measure changes in tensile stress and strain however, the accuracy of this simple method is limited. Therefore, in the present study, we established three-dimensional finite element models of sciatic nerve defects repaired by autologous nerve grafts. Using PRO E 5.0 finite element simulation software, we calculated the maximum stress and displacement of an anastomosis under a 5 N load in 10-, 20-, 30-, 40-mm long autologous nerve grafts. We found that maximum displacement increased with graft length, consistent with specimen force. These findings indicate that three-dimensional finite element simulation is a feasible method for analyzing stress and displacement at the anastomosis after autologous nerve grafting.

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.

Challenges in a larger bladder replacement with cell-seeded and unseeded small intestinal submucosa grafts in a subtotal cystectomy model.

Science.gov (United States)

Zhang, Yuanyuan; Frimberger, Dominic; Cheng, Earl Y; Lin, Hsueh-Kung; Kropp, Bradley P

2006-11-01

To evaluate small intestinal submucosa (SIS), unseeded or seeded, as a possible augmentation material in a canine model of subtotal cystectomy. In all, 22 male dogs had a 90% partial cystectomy and were then divided into three groups. At 1 month after the initial cystectomy, dogs in group 1 (unseeded, six) and group 2 (seeded, six) received a bladder augmentation with a corresponding SIS graft. The dogs in group 3 (ten) received no further surgery and were considered the surgical control group. All dogs were evaluated before and after surgery with blood chemistry, urine culture, intravenous urography, cystograms and cystometrograms. After surgery (at 1, 5 and 9 months), the bladders were examined using routine histology and immunohistochemistry. All 22 dogs survived the subtotal cystectomy, and 18 survived their intended survival period. One dog, in group 2 (seeded), was killed at 1 month after augmentation due to bladder perforation caused by a large piece of incompletely absorbed SIS. Three other dogs (group 1, two; and group 2, one) were killed within 2 months after augmentation due to bladder obstruction by stones. Group 1 and group 2 SIS grafts had moderate to heavy adhesion, graft shrinkage, and some had bone and calcification at the graft site. Histologically, there was limited bladder regeneration in both groups. Interestingly, dogs in group 3 at 1 month after cystectomy (when group 1 and 2 received their augmentations) had severely shrunken bladders and histologically had severe inflammation, fibroblast infiltration and muscle hypertrophy. These results verify the subtotal cystectomy model. The use of seeded or unseeded SIS in a subtotal cystectomy model does not induce the same quality and quantity of bladder regeneration that is seen in the 40% non-inflammatory cystectomy model. This study provides important insights into the process of regeneration in a severely damaged bladder. The results led us to re-evaluate the critical elements required for a

Dynamics in coarse-grained models for oligomer-grafted silica nanoparticles

KAUST Repository

Hong, Bingbing; Chremos, Alexandros; Panagiotopoulos, Athanassios Z.

2012-01-01

transferability with respect to chain lengths and temperature, but structure and dynamics of grafted nanoparticle systems exhibit a strong dependence on the core-core interactions. This leads to poor transferability of the core potential to conditions different

Prediction of coronary artery bypass graft flow

International Nuclear Information System (INIS)

Tamiya, Eiji; Hada, Yoshiyuki; Asano, Ken-ichi; Iio, Masahiro.

1991-01-01

To predict the coronary artery bypass graft (CABG) flow based on the time density curve (TDC) obtained from the digital subtraction aortograms (DSA), we developed a pulsatile CABG model (perfusion pressure 60,130 mmHg, pulse rate 53,126/min, cardiac output 3-7 l/min, diameter of the graft 2.1∼6.0 mm). After positioning the regions of interest (ROI), we injected contrast medium(5∼40 ml/sec, 5∼40 ml) into the outlet conduit. Concerning the TDCs, we calculated appearance time (Ta), peak densities (Dp), peak time (Tp), disappearance time (Td), integral of TDC, ΔTp (difference of Tp between two ROI) and ΔTa (difference of Ta between two ROI). Perfusion pressure, graft flow and output curve were similar to those of patients with CABG. Ta, Tp, Td, and ΔTp were affected by both the injection rate and the volume of the contrast medium; while Dp and the TDC integral were only affected by the latter parameter. Under the same conditions of contrast medium injection, the TDC depended strongly on graft flow, diameter of the graft, output and pulse rate. 21.6+0.92π·d 2 /4·Δ1/ΔTp·60 provided the most accurate estimation of CABG flow (r=0.865, p<0.01). We conclude that densitometric analysis of DSA may be useful in the prediction of CABG flow. (author)

Mild anastomotic stenosis in patient-specific CABG model may enhance graft patency: a new hypothesis.

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Yunlong Huo

Full Text Available It is well known that flow patterns at the anastomosis of coronary artery bypass graft (CABG are complex and may affect the long-term patency. Various attempts at optimal designs of anastomosis have not improved long-term patency. Here, we hypothesize that mild anastomotic stenosis (area stenosis of about 40-60% may be adaptive to enhance the hemodynamic conditions, which may contribute to slower progression of atherosclerosis. We further hypothesize that proximal/distal sites to the stenosis have converse changes that may be a risk factor for the diffuse expansion of atherosclerosis from the site of stenosis. Twelve (12 patient-specific models with various stenotic degrees were extracted from computed tomography images using a validated segmentation software package. A 3-D finite element model was used to compute flow patterns including wall shear stress (WSS and its spatial and temporal gradients (WSS gradient, WSSG, and oscillatory shear index, OSI. The flow simulations showed that mild anastomotic stenosis significantly increased WSS (>15 dynes · cm(-2 and decreased OSI (<0.02 to result in a more uniform distribution of hemodynamic parameters inside anastomosis albeit proximal/distal sites to the stenosis have a decrease of WSS (<4 dynes · cm(-2. These findings have significant implications for graft adaptation and long-term patency.

Mild anastomotic stenosis in patient-specific CABG model may enhance graft patency: a new hypothesis.

Science.gov (United States)

Huo, Yunlong; Luo, Tong; Guccione, Julius M; Teague, Shawn D; Tan, Wenchang; Navia, José A; Kassab, Ghassan S

2013-01-01

It is well known that flow patterns at the anastomosis of coronary artery bypass graft (CABG) are complex and may affect the long-term patency. Various attempts at optimal designs of anastomosis have not improved long-term patency. Here, we hypothesize that mild anastomotic stenosis (area stenosis of about 40-60%) may be adaptive to enhance the hemodynamic conditions, which may contribute to slower progression of atherosclerosis. We further hypothesize that proximal/distal sites to the stenosis have converse changes that may be a risk factor for the diffuse expansion of atherosclerosis from the site of stenosis. Twelve (12) patient-specific models with various stenotic degrees were extracted from computed tomography images using a validated segmentation software package. A 3-D finite element model was used to compute flow patterns including wall shear stress (WSS) and its spatial and temporal gradients (WSS gradient, WSSG, and oscillatory shear index, OSI). The flow simulations showed that mild anastomotic stenosis significantly increased WSS (>15 dynes · cm(-2)) and decreased OSI (<0.02) to result in a more uniform distribution of hemodynamic parameters inside anastomosis albeit proximal/distal sites to the stenosis have a decrease of WSS (<4 dynes · cm(-2)). These findings have significant implications for graft adaptation and long-term patency.

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)

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...

Differential kinetics of response and toxicity using stereotactic radiation and interventional radiological coiling for pulmonary arterio-venous shunting from metastatic leiomyosarcoma

International Nuclear Information System (INIS)

Wong, Annie Ngai Man; Siva, Shankar; Chin, Kwang; Manser, Renee; Antippa, Phillip; Dowling, Richard; Mileshkin, Linda Rose

2015-01-01

Case report demonstrating the differential kinetics of response and toxicity using stereotactic radiation and interventional radiological coiling for pulmonary arterio-venous shunting from leiomyosarcoma pulmonary metastases.

Immobilized enzymes in blood plasma exchangers via radiation grafting

Science.gov (United States)

Gombotz, Wayne; Hoffman, Allan; Schmer, Gottfried; Uenoyama, Satoshi

The enzyme asparaginase was immobilized onto a porous hollow polypropylene (PP) fiber blood plasma exchange device for the treatment of acute lymphocytic leukemia. The devices were first radiation grafted with polymethacrylic acid (poly(MAAc)). This introduces carboxyl groups onto the surface of the fibers. Several variables were studied in the grafting reaction including the effects of solvent type and monomer concentration. The carboxyl groups were activated with N-hydroxy succinimide (NHS) using carbodiimide chemistry. Asparaginase was then covalently immobilized on the activated surfaces. Quantitative relationships were found relating the percent graft to the amount of immobilized enzyme which was active. The enzyme reactor was tested both in vitro and in vivo using a sheep as an animal model.

Budget impact analysis of heparin-bonded polytetrafluoroethylene grafts (Propaten) against standard polytetrafluoroethylene grafts for below-the-knee bypass in patients with critical limb ischaemia in France

Science.gov (United States)

Vergnaud, Simon; Riche, Valéry-Pierre; Tessier, Philippe; Mauduit, Nicolas; Kaladji, Adrien; Gouëffic, Yann

2018-01-01

Objectives To evaluate the budget impact of progressive replacement of standard polytetrafluoroethylene (PTFE) grafts by heparin-bound PTFE (Propaten) for below-the-knee (BTK) bypass in patients with critical limb ischaemia (CLI). Design From a review of the scientific literature, we calculated a theoretical BTK primary patency for Propaten grafts. Using the French hospital expenditure database (PMSI), we retrospectively estimated a rehospitalisation rate for standard PTFE grafts. From these data, a model was created to assess the budget impact of a progressive replacement from standard PTFE grafts to Propaten grafts over a 5-year horizon. We performed an univariate sensitivity analysis to assess the robustness of our results. Setting French National Health Insurance (FNHI) perspective. Participant Patients with CLI. Main outcome measures Budget impact analysis. Results Data extraction from the PMSI revealed that 656 patients were treated with PTFE grafts in 2011 in French public hospitals for a BTK bypass. Assuming a 2-year survival rate of 76.8%, observed reinterventions rate for standard PTFE grafts at 24 months from the PMSI was 35.1%. The mean rehospitalisation cost was €10 689. The budget impact analysis based on these data found a net cumulative 5-year payer budget reduction of €112 420 in favour of Propaten, under the assumption of a 75.6% primary patency for Propaten grafts for a projected population of 3215 patients of which 801 received a Propaten graft. Conclusions Our budget impact analysis showed a positive impact on the national health insurance budget of the replacement of standard PTFE grafts by Propaten grafts for BTK bypass in patients with CLI in France. This supports the enactment of a reimbursement policy by the FNHI. PMID:29490953

Three-Dimensional Finite Element Analysis of Maxillary Sinus Floor Augmentation with Optimal Positioning of a Bone Graft Block

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Peter Schuller-Götzburg

2018-01-01

Full Text Available Purpose: the aim of the computational 3D-finite element study is to evaluate the influence of an augmented sinus lift with additional inserted bone grafting. The bone graft block stabilizes the implant in conjunction with conventional bone augmentation. Two finite element models were applied: the real geometry based bone models and the simplified geometry models. The bone graft block was placed in three different positions. The implants were loaded first with an axial force and then with forces simulating laterotrusion and protrusion. This study examines whether the calculated stress behavior is symmetrical for both models. Having established a symmetry between the primary axis, the laterotrusion and protrusion behavior reduces calculation efforts, by simplifying the model. Material and Methods: a simplified U-shaped 3D finite element model of the molar region of the upper jaw and a more complex anatomical model of the left maxilla with less cortical bone were created. The bone graft block was placed in the maxillary sinus. Then the von Mises stress distribution was calculated and analyzed at three block positions: at contact with the sinus floor, in the middle of the implant helix and in the upper third of the implant. The two finite element models were then compared to simplify the modelling. Results: the position of the bone graft block significantly influences the magnitude of stress distribution. A bone graft block positioned in the upper third or middle of the implant reduces the quantity of stress compared to the reference model without a bone graft block. The low bone graft block position is clearly associated with lower stress distribution in compact bone. We registered no significant differences in stress in compact bone with regard to laterotrusion or protrusion. Conclusions: maximum values of von Mises stresses in compact bone can be reduced significantly by using a bone graft block. The reduction of stress is nearly the same for

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.

Graft-copolymerization onto carbon black

International Nuclear Information System (INIS)

Nakase, Yoshiaki; Nishii, Masanobu; Kijima, Toshiyuki; Kato, Hiroshi.

1988-07-01

Radiation-induced graft copolymerization of vinyl monomer onto carbon black was performed. During the γ-ray- and electron beam-induced polymerization (In-source), or the electron beam post-polymerization, the graft-copolymerization behavior was affected by the kinds of both carbon blacks and monomers, i.e. the smaller the size of carbon black particles, the higher the apparent grafted fraction. Homopolymer in the grafted carbon black samples was washed out by the solvent of the polymer, and the extracted polymer seemed to be dimer or trimer of the used monomer. In the case of the post-polymerization with the pre-irradiation doses of 50 Mrad, homopolymer was hardly observed. The polymer sheets of plastics or rubbers with grafted carbon black had an electrical conductivity unalterable considerably by the heating cycles. The particles of grafted carbon black in the sheet might be kept much more at the surface layer within 100 nm depth than at the inner layer. (author)

Radiation-induced grafting of TMPM onto polypropylene

International Nuclear Information System (INIS)

Wang Huiliang; Li Hong; Chen Wenxiu

1995-01-01

The gamma radiation-induced graft copolymerization of 2,2,6,6-tetramethyl-4-piperidinyl-methacrylate (TMPM), a very effective hindered amine light stabilizer (HALS), onto polypropylene was investigated by simultaneous- irradiation technique. The various synthesis conditions on the graft content was studied. It was found that benzene, CCl 4 and petroleum ether are more effective than other solvents, the percent grafting reached 7.1% for benzene. The percent grafting is higher when graft copolymerization is carried out in argon atmosphere than those in air. For all the grafting copolymerization carried out in benzene and CCl 4 , percent grafting increase linearly from 1 to 5 Mrad and beyond 5 Mrad, a tendency to level off appeared. At a constant dose, the percent grafting was found to be higher at high dose rate until 228 rad/s. Percent grafting also increased continuously with increasing monomer concentration up to 2.85 mol/L, but significant increase in grafting was observed only up to 1.14 mol/L

Salt-Induced Control of the Grafting Density in Poly(ethylene glycol) Brush Layers by a Grafting-to Approach

DEFF Research Database (Denmark)

Ortiz, Roberto; Olsen, Stefan; Thormann, Esben

2018-01-01

In this work, a method to obtain control of the grafting density during the formation of polymer brush layers by the grafting-to method of thiolated poly(ethylene glycol) onto gold is presented. The grafting density of the polymer chains was adjusted by adding Na2SO4 in concentrations between 0.......2 and 0.9 M to the aqueous polymer solution during the grafting process. The obtained grafting densities ranged from 0.26 to 1.60 chains nm-2, as determined by surface plasmon resonance. The kinetics of the grafting process were studied in situ by a quartz crystal microbalance with dissipation......, and a mushroom to brush conformational transition was observed when the polymer was grafted in the presence of Na2SO4. The transition from mushroom to brush was only observed for long periods of grafting, highlighting the importance of time to obtain high grafting densities. Finally, the prepared brush layer...

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)

Rare malformation of glans penis: arteriovenous malformation.

Science.gov (United States)

Akin, Y; Sarac, M; Yucel, S

2013-01-01

Pediatric glans penis malformations, especially arteriovenous malformations (AVM), are very rare. Herein, we report two rare cases. A 14-year-old boy attended our outpatient clinic with chief complaints of purple swelling and rapidly growing lesion on the glans penis. The lesion was excised surgically after physical and radiological evaluations. Pathology reported AVM and the patient is being followed up. The second case is a 2-year-old boy who was admitted with a big lesion involving glans penis and genital area that has been present since birth. In physical and radiological evaluations, lesion on the glans penis was pulsatile. Parents of the patient did not want any surgery and patient has been in follow-up. Diagnosis of the vascular lesions on glans penis is very easy by physical and radiological examinations today. Long-term follow-up is very important for AVM. Clinicians must make a careful effort to document new glans lesions in the pediatric population and decrease anxiety in the parents of affected children.

Transcatheter coil embolisation of pulmonary arteriovenous malformations

International Nuclear Information System (INIS)

Wingen, M.; Guenther, R.W.

2001-01-01

Evaluation of technical success, complications and long-term results of transcatheter coil embolisation in pulmonary arteriovenous malformations (pAVMs). Material and Methods: Transcatheter embolisations of 46 pAVMs in 14 patients were analysed retrospectively, and, 5 years after treatment, the patients were interviewed by telefone concerning persistent symptoms and complications. Main symptoms before embolisation were dyspnoe (86%), hypoxaemia (100%), cerebral ischemia (21%), and hemoptysis (14%); 11 patients (79%) suffered from hereditary hemorrhagic telangiectasia. Results: Embolisation with an average of 3,9 coils (min. 1, max. 19 coils) per pAVM yielded technical success in all cases. Only two minor complications, transitory pleuritis and a small lung infarction were observed. On follow up examination after 5 years either no residual complaints or substantial improvement of dyspnoe were reported; no patient suffered from neurologic or hemorrhagic complications after the embolisation. Conclusion: Transcatheter embolisation is a safe and minimally invasive therapy for pAVMs and has rightfully replaced surgical resection as the therapy of choice. (orig.) [de

Modeling polymer-induced interactions between two grafted surfaces: comparison between interfacial statistical associating fluid theory and self-consistent field theory.

Science.gov (United States)

Jain, Shekhar; Ginzburg, Valeriy V; Jog, Prasanna; Weinhold, Jeffrey; Srivastava, Rakesh; Chapman, Walter G

2009-07-28

The interaction between two polymer grafted surfaces is important in many applications, such as nanocomposites, colloid stabilization, and polymer alloys. In our previous work [Jain et al., J. Chem. Phys. 128, 154910 (2008)], we showed that interfacial statistical associating fluid density theory (iSAFT) successfully calculates the structure of grafted polymer chains in the absence/presence of a free polymer. In the current work, we have applied this density functional theory to calculate the force of interaction between two such grafted monolayers in implicit good solvent conditions. In particular, we have considered the case where the segment sizes of the free (sigma(f)) and grafted (sigma(g)) polymers are different. The interactions between the two monolayers in the absence of the free polymer are always repulsive. However, in the presence of the free polymer, the force either can be purely repulsive or can have an attractive minimum depending upon the relative chain lengths of the free (N(f)) and grafted polymers (N(g)). The attractive minimum is observed only when the ratio alpha = N(f)/N(g) is greater than a critical value. We find that these critical values of alpha satisfy the following scaling relation: rho(g) square root(N(g)) beta(3) proportional to alpha(-lambda), where beta = sigma(f)/sigma(g) and lambda is the scaling exponent. For beta = 1 or the same segment sizes of the free and grafted polymers, this scaling relation is in agreement with those from previous theoretical studies using self-consistent field theory (SCFT). Detailed comparisons between iSAFT and SCFT are made for the structures of the monolayers and their forces of interaction. These comparisons lead to interesting implications for the modeling of nanocomposite thermodynamics.

Development of Highly Efficient Grafting Technique and Synthesis of Natural Polymer-Based Graft Adsorbent

Energy Technology Data Exchange (ETDEWEB)

Ueki, Y; Seko, N; Tamada, M [Japan Atomic Energy Agency, Quantum Beam Science Directorate, Takasaki (Japan)

2012-09-15

In the framework of the CRP, Japan has focused on the development of fibrous adsorbents for removal of toxic metal ions and recovery of significant metal ions from industrial wastewater and streaming water. Graft polymerization was carried out by using gamma irradiation facility and electron beam accelerator. Emulsion grafting is a novel topic for synthesis of metal ion adsorbents which are prepared from fibrous trunk polymers such as polyethylene fibre and biodegradable nonwoven fabrics. The emulsion grafting, where monomer micelles are dispersed in water in the presence of surfactant, is a highly efficient and economic grafting technique as compared to general organic solvent system. The resultant cotton-based adsorbent has high adsorption efficiency and high adsorption capacity for Hg, besides, it is biodegradable. Polylactic acid can also be used as a trunk material for the grafting. (author)

Vasoactive intestinal polypeptide (VIP) in cirrhosis: arteriovenous extraction in different vascular beds

DEFF Research Database (Denmark)

Henriksen, Jens Henrik Sahl; Staun-Olsen, P; Fahrenkrug, J

1980-01-01

The concentration of vasoactive intestinal polypeptide (VIP) was determined in peripheral venous plasma from 136 patients with liver cirrhosis without gastrointestinal bleeding or coma and from 112 controls. In eight patients (cirrhosis, six; fibrosis, one; steatosis, one) arteriovenous extraction...... is significantly elevated in peripheral plasma from patients with cirrhosis, probably due to porto-systemic shunting and/or compromised hepatic elimination. Hepatic elimination is still likely to account for the inactivation of most of the VIP escaping from the neurosynapses throughout the body in patients...

Pial Arteriovenous Fistula Caused by Trauma: A Case Report.

Science.gov (United States)

Nomura, Seiji; Ishikawa, Osamu; Tanaka, Kentaro; Otani, Ryohei; Miura, Keisuke; Maeda, Keiichiro

2015-01-01

We report an extremely rare case of pial arteriovenous fistula (AVF) caused by trauma. A 61-year-old man suffered from brain contusion by a traffic accident. He was neurologically normal on admission. However, his headache gradually worsened, and partial seizures occurred thereafter. He presented with general tonic seizure 7 days after the head injury. Magnetic resonance imaging demonstrated the exacerbation of brain edema and an abnormal vein near the contusion. Subsequent angiography showed a pial AVF, which was considered to be responsible for the brain edema. After treatment of the AVF by direct surgery, the brain edema was ameliorated. We should take into consideration the formation of vascular disease in cases with unexpected worsening of edema after brain injury.

Three-dimensional computer-aided human factors engineering analysis of a grafting robot.

Science.gov (United States)

Chiu, Y C; Chen, S; Wu, G J; Lin, Y H

2012-07-01

The objective of this research was to conduct a human factors engineering analysis of a grafting robot design using computer-aided 3D simulation technology. A prototype tubing-type grafting robot for fruits and vegetables was the subject of a series of case studies. To facilitate the incorporation of human models into the operating environment of the grafting robot, I-DEAS graphic software was applied to establish individual models of the grafting robot in line with Jack ergonomic analysis. Six human models (95th percentile, 50th percentile, and 5th percentile by height for both males and females) were employed to simulate the operating conditions and working postures in a real operating environment. The lower back and upper limb stresses of the operators were analyzed using the lower back analysis (LBA) and rapid upper limb assessment (RULA) functions in Jack. The experimental results showed that if a leg space is introduced under the robot, the operator can sit closer to the robot, which reduces the operator's level of lower back and upper limbs stress. The proper environmental layout for Taiwanese operators for minimum levels of lower back and upper limb stress are to set the grafting operation at 23.2 cm away from the operator at a height of 85 cm and with 45 cm between the rootstock and scion units.

Design of a Sapling Branch Grafting Robot