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Sample records for aaa graft replacement

  1. Midterm outcomes of the Zenith Renu AAA Ancillary Graft.

    PubMed

    Jim, Jeffrey; Rubin, Brian G; Geraghty, Patrick J; Money, Samuel R; Sanchez, Luis A

    2011-08-01

    The Zenith Renu abdominal aortic aneurysm (AAA) Ancillary Graft (Cook Medical Inc, Bloomington, Ind) provides active proximal fixation for treatment of pre-existing endografts with failed or failing proximal fixation or seal. The purpose of this study was to evaluate the midterm outcomes of treatment with this device. From September 2005 to November 2006, a prospective, nonrandomized, multicenter, postmarket registry was utilized to collect physician experiences from 151 cases (89 converters and 62 main body extensions) at 95 institutions. Preoperative indications and procedural and postimplantation outcomes were collected and analyzed. Technical success and clinical success were determined as defined by the Society of Vascular Surgery reporting standards. Patients were predominantly male (87%) with a mean age of 77 years. The interval between the original endograft implantation to Renu treatment was 43.4 ± 18.7 months. The indications for treatment were endoleak (n = 111), migration (n = 136), or both (n = 94). Technical success was 98.0% with two cases of intraoperative conversion and one case of persistent type IA endoleak. The median follow-up for the cohort was 45.0 months (range, 0-56 months; interquartile range, 25.0 months). Overall, 32 cases had treatment failures that included at least one of the following: death (n = 5), type I/III endoleak (n = 18), graft infection (n = 1), thrombosis (n = 1), aneurysm enlargement >5 mm (n = 9), rupture (n = 4), conversion (n = 9, with 7 after 30 days), and migration (n = 1). Overall, the clinical success for the entire cohort during the follow-up period was 78.8% (119/151). The postmarket registry data confirm that the Zenith Renu AAA Ancillary Graft can be used to treat endovascular repairs that failed due to proximal attachment failures. The salvage treatment with the Renu device had high technical success rate and resulted in clinical success in a majority of patients (78.8%). While failed endovascular repairs can

  2. Combination of endovascular graft exclusion and drug therapy in AAA with hypertension or hyperglycemia.

    PubMed

    Wang, Dile; Qu, Bihui; He, Tao

    2017-08-01

    The objective of the present study was to evaluate the efficacy of combination of endovascular graft exclusion and drugs for hypertension/hyperglycemia for the treatment of abdominal aortic aneurysm (AAA). We analyzed 156 patients with AAA. Eighty-four patients were hypertensive and 72 were hyperglycemic. After endovascular graft exclusion, hypertensive patients were divided into four groups and treated with cyclopenthiazide, reserpine, propranolol, and placebo respectively. Hyperglycemic patients were divided into three groups and treated with metformin, insulin, and placebo respectively. Body temperature and peripheral blood leukocytes were measured at day 1, 2, 7, and 14 after endovascular graft exclusion. Size of AAAs, blood pressure, and blood sugar were measured again after 1 year. In hypertensive patients, the size of AAAs reduced after endovascular graft exclusion, while the combined treatments with cyclopenthiazide, reserpine, or propranolol helped to reduce blood pressure (blood pressure decrease <10 mmHg (18/21), <10 mmHg (12/21), <10 mmHg (8/21), and <10 mmHg (10/21) in the control group, cyclopenthiazide group, reserpine group, and propranolol group, respectively. AAA size decreased in the control group (P<0.001) and in the other three groups (P<0.0001). Similar results were obtained in hyperglycemic patients. The size of AAAs reduced after endovascular graft exclusion. Combined treatment with Metformin and Insulin reduced blood sugar (control, blood sugar >7.8 mmol/L (22/24), AAA size (P<0.001); metformin, blood sugar >7.8 mmol/L (14/24), AAA size (P<0.0001); insulin, blood sugar >7.8 mmol/L (11/24), AAA size (P<0.0001). Combination of endovascular graft exclusion with medicine is more effective than the former treatment alone for AAA therapy.

  3. Costochondral grafts replacing the mandibular condyle.

    PubMed

    Ross, R B

    1999-07-01

    The purpose of this study was to determine the success rate of costochondral bone grafts used to replace absent or nonfunctioning temporomandibular joints and the subsequent growth of these grafts when placed in young children. This is a retrospective study of all cases with adequate follow-up records that were treated at the Craniofacial Centre at Toronto's The Hospital for Sick Children from 1974-1986. A total of 55 patients were evaluated, of whom 13 were growing children. The findings suggest that there was increased success when surgery was performed at an early age. Poorer results were achieved when previous surgery had been performed or when pathology was present. Growth of the graft did not always equal the growth of the "normal" side, but in most cases a satisfactory symmetry was achieved. Several cases exhibited excessive overgrowth. Surgery at 4 to 5 years of age will alleviate the impact of a severe facial deformity on the child during the early school years, when self-esteem is fragile and patterns of social interactions are developing. Development of the dentition is better if the jaw relationship is close to normal at an early age. It would appear that early temporomandibular joint (TMJ) construction by costochondral grafting is, at present, the method of choice for severe hemifacial microsomia.

  4. Aortic Replacement with Sutureless Intraluminal Grafts

    PubMed Central

    Lemole, Gerald M.

    1990-01-01

    To avoid the anastomotic complications and long cross-clamp times associated with standard suture repair of aortic lesions, we have implanted sutureless intraluminal grafts in 122 patients since 1976. Forty-nine patients had disorders of the ascending aorta, aortic arch, or both: their operative mortality was 14% (7 patients), and the group's 5-year actuarial survival rate has been 64%. There have been no instances of graft dislodgment, graft infection, aortic bleeding, or pseudoaneurysm formation. Forty-two patients had disorders of the descending aorta and thoracoabdominal aorta: their early mortality was 10% (4 patients), and the group's 5-year actuarial survival rate has been 56%. There was 1 early instance of graft dislodgment, but no pseudoaneurysm formation, graft erosion, aortic bleeding, intravascular hemolysis, or permanent deficits in neurologic, renal, or vascular function. Thirty-one patients had the sutureless intraluminal graft implanted in the abdominal aortic position: their early mortality was 6% (2 patients), and the 5-year actuarial survival rate for this group has been 79%. There were no instances of renal failure, ischemic complication, postoperative paraplegia, pseudoaneurysm, or anastomotic true aneurysm. Our recent efforts have been directed toward developing an adjustable spool that can adapt to the widest aorta or the narrowest aortic arch vessel; but in the meanwhile, the present sutureless graft yields shorter cross-clamp times, fewer intraoperative complications, and both early and late results as satisfactory as those afforded by traditional methods of aortic repair. (Texas Heart Institute Journal 1990; 17:302-9) Images PMID:15227522

  5. The INNOVATION Trial: four-year safety and effectiveness of the INCRAFT® AAA Stent-Graft System for endovascular repair.

    PubMed

    Pratesi, Giovanni; Pratesi, Carlo; Chiesa, Roberto; Coppi, Gioacchino; Scheinert, Dierk; Brunkwall, Jan S; van der Meulen, Stefaan; Torsello, Giovanni

    2017-10-01

    This paper reports the 4-year safety and effectiveness of the INCRAFT® AAA Stent-Graft System (Cordis Corp., Milpitas, CA, USA), an ultra-low-profile device for the treatment of abdominal aortic aneurysms. The INNOVATION Trial is the prospective, first-in-human, multicenter trial to evaluate the safety and effectiveness of the INCRAFT® System. Patients underwent annual clinical and computed tomography angiography examination as part of the study protocol. The INCRAFT® AAA Stent-Graft System is a customizable tri-modular design, with an ultra-low profile (14-Fr) delivery system. Patient were treated under approved protocol, the prescribed clinical and imaging follow-up at annually through 5 years. Results analyzed and adjudicated by a clinical events committee, independent core laboratory, and a data safety and monitoring board. This manuscript reports results through 4 years of follow-up. A total of 60 patients were enrolled in the trial, all of whom were successfully treated. Follow-up rates at 1 and 4 years were 93% (56/60) and 85% (51/60), respectively. All-cause mortality at 4 years was 17.6% and no death was AAA-, device-, or procedure-related. The secondary reintervention rate at 1 year was 4.6%, primarily the result of stent thrombosis. In total, 10 patients required 13 post-procedure interventions within 4-years of follow-up (2 to repair a type I endoleak, 4 to repair a type II endoleak, 1 for stent thrombosis, 1 for renal stenosis, 1 for aneurysm enlargement, 2 for limb migration and 2 for prosthesis stenosis or occlusion). There were 4 cases (10%) of aneurysm enlargement reported at the 4 year follow-up. At 4 years, 38 out of 39 patients were free from type I and III endoleaks. There were no proximal type I or type III endoleaks at 4-year follow-up. Core laboratory evaluation of the postoperative imaging studies indicated absence of endograft migration while a single fracture was demonstrated without any clinical sequelae. The INCRAFT® AAA Stent-Graft

  6. Outcome of total arch replacement with coronary artery bypass grafting.

    PubMed

    Takashima, Noriyuki; Suzuki, Tomoaki; Asai, Tohru; Nota, Hiromitsu; Ikegami, Hirohisa; Kinoshita, Takeshi; Fujino, Susumu; Hosoba, Soh

    2015-06-01

    There are few reports on the outcome of total arch replacement (TAR) with concomitant coronary artery bypass grafting (CABG); the present study was aimed at analysing outcomes after TAR with CABG at our institute. Between January 2002 and December 2012, 123 consecutive patients underwent elective TAR with or without CABG. The patients were divided into two groups: 46 who had concomitant CABG (Group T/C) and the rest, who had TAR only (Group T). TAR was performed under mild hypothermic circulatory arrest and selective antegrade cerebral perfusion (SACP) using a four-branched arch graft. The number with a low ejection fraction (<50%) was higher in Group T/C, in which the additive and the logistic EuroSCORE were also higher. The mean number of coronary anastomoses was 1.6 ± 0.8 in Group T/C. The mean durations of surgery (P < 0.01), cardiopulmonary bypass (P < 0.01), cardiac ischaemia (P < 0.01) and SACP (P < 0.01) were significantly longer in Group T/C. The early graft patency of bypass grafts was 96.7%. Between Group T and Group T/C, there were no significant differences in the incidence of stroke (3.9 and 10.9%, P = 0.13), perioperative myocardial infarction (0 and 2.2%, P = 0.37) and in-hospital mortality (2.6 and 8.7%, P = 0.14). There was one case of 30-day mortality in each group. Preoperative haemodialysis, NYHA III/IV and operation time were multivariate predictors (P < 0.05) of in-hospital mortality. Although concomitant CABG in TAR patients had higher operative risk, it can be safely performed with favourable outcomes. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  7. Complications at the Proximal Landing Zone of Endovascular Stent Grafts Deployed in Surgically Replaced Ascending Aorta.

    PubMed

    Kotha, Vamshi K; Herget, Eric J; Appoo, Jehangir J

    2016-11-01

    The ascending aorta, with its hostile angulations and forces, is the next frontier in the evolution of endovascular surgery. Type II hybrid arch repair, involving surgical replacement of the ascending aorta, arch debranching, and stent graft deployment in the ascending aortic graft, offers an opportunity to study the behavior of an endovascular prosthesis in the ascending aorta. We report complications seen at the proximal landing zone after type II hybrid arch repair. A dedicated imaging protocol was used to monitor 20 consecutive patients who underwent type II hybrid arch repair at a single center from June 2009 to July 2014. Mean age was 66 years (range, 47 to 82 years). Mean imaging follow-up was 34 months (range, 12 to 64 months). There was 1 operative death (5%). Bird beaking (>5 mm of nonapposition) of the stent graft at the proximal landing zone occurred in 12 patients, and >20 mm of bird beaking occurred in 7 patients. Proximal landing zone complications occurred in 4 patients (20%), comprising 2 type Ia endoleaks, 1 graft migration, and 1 graft infolding detected on postoperative days 4, 11, 5, and 755, respectively. Three patients underwent endovascular reintervention for proximal landing zone complications. There were no late deaths. Thoracic aortic stent grafts may be prone to proximal landing zone complications when deployed in the ascending aorta. Bird beaking is common when endografts are deployed in the Dacron (DuPont, Wilmington, DE) ascending aorta. Angulation issues will likely need to be overcome by stent graft refinement to enable future closed chest approaches to the ascending aorta. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  8. Aortic valve replacement and concomitant right coronary artery bypass grafting performed via a right minithoracotomy approach.

    PubMed

    Mihos, Christos G; Santana, Orlando; Pineda, Andres M; La Pietra, Angelo; Lamelas, Joseph

    2014-01-01

    We present our experience of concomitant right coronary artery bypass grafting (CABG) and aortic valve replacement performed via a right minithoracotomy in patients with coronary lesions not amenable to percutaneous intervention. A total of 17 patients underwent concomitant aortic valve replacement and right CABG between April 2008 and July 2013. A 5- to 6-cm minithoracotomy incision was made over the right second or third intercostal space, and the costochondral cartilage was transected. A saphenous vein bypass to the right coronary artery was then performed, initiating the anastomosis from the toe of the graft. Subsequently, the aortic valve was replaced using standard techniques. There were 6 men and 11 women. The median European System for Cardiac Operative Risk Evaluation II score mortality risk was 5% [interquartile range (IQR), 2%-8%]. The mean (SD) age was 77 (10) years, the left ventricular ejection fraction was 59% (8%), and the New York Heart Association functional class was 2.4 (0.8). One patient had a history of CABG. The mean (SD) cardiopulmonary bypass time was 168 (57) minutes, and the aortic cross-clamp time was 133 (36) minutes. Three patients underwent concomitant mitral valve surgery (replacement, 2; repair, 1). The median intensive care unit and hospital lengths of stay were 47 hours (IQR, 24-90) and 9 days (IQR, 5-13), respectively. There was one reoperation for bleeding, and there was one postoperative stroke. All patients were alive at a mean (SD) follow-up of 2 (1.1) years. Aortic valve replacement with concomitant CABG performed via a right minithoracotomy approach is feasible.

  9. A Retrospective Analysis of Dental Implants Replacing Failed Implants in Grafted Maxillary Sinus: A Case Series.

    PubMed

    Manor, Yifat; Chaushu, Gavriel; Lorean, Adi; Mijiritzky, Eithan

    2015-01-01

    To evaluate the survival rate of dental implants replacing failed implants in grafted maxillary sinuses using the lateral approach vs nongrafted posterior maxillae. A retrospective analysis was conducted to study the survival of secondary dental implants inserted in the posterior maxilla in previously failed implant sites between the years 2000 and 2010. The study group consisted of patients who had also undergone maxillary sinus augmentation, and the control group consisted of patients in whom implants in the posterior maxilla had failed. Clinical and demographic data were analyzed using a structured form. Seventy-five patients with a total of 75 replaced implants were included in the study. The study group comprised 40 patients and the control group, 35 patients. None of the replaced implants in the study group failed, resulting in an overall survival of 100%; three replaced implants in the control group failed (92% survival). The main reason for the primary implant removal was lack of osseointegration (35 [87.5%] of 40 study group implants and 23 [65.7%] of 35 control group implants [P = .027]). The difference between the groups with regard to the timing of primary implant failure was statistically significant. The study group had more early failures of the primary implant than did the control group (77% vs 62%; P = .038). Dental implants replaced in the posterior maxilla had a high survival rate. A higher rate of survival was found in augmented maxillary sinus sites. Within the limits of the present study, it can be concluded that previous implant failures in the grafted maxillary sinus should not discourage practitioners from a second attempt.

  10. Aortic valve replacement for stenosis with or without coronary artery bypass grafting after 2 previous isolated coronary artery bypass grafting operations

    PubMed Central

    Lee Henry, Christopher; Ko, Jong Mi; Henry, Albert Carl; Matter, Gregory John

    2011-01-01

    Aortic valve replacement following an earlier coronary artery bypass grafting (CABG) procedure is fairly common. When this situation occurs, the type of valve dysfunction is usually stenosis (with or without regurgitation), and whether it was missed at the time of the earlier CABG or developed subsequently is usually unclear. We attempted to determine the survival in patients who had had aortic valve replacement after 2 previous CABG procedures. We describe 12 patients who had aortic valve replacement for aortic stenosis; rather than one previous CABG operation, all had had 2 previous CABG procedures. Only one patient died in the early postoperative period after aortic valve replacement, and the remaining 11 were improved substantially: all have lived at least 11 months, and one is still alive at over 101 months after aortic valve replacement. Aortic valve replacement remains beneficial for most patients even after 2 previous CABG procedures. PMID:21307968

  11. Dacron graft as replacement to dissected aorta: A three-dimensional fluid-structure-interaction analysis.

    PubMed

    Jayendiran, R; Nour, B M; Ruimi, A

    2018-02-01

    Aortic dissection (AD) is a serious medical condition characterized by a tear in the intima, the inner layer of the aortic walls. In such occurrence, blood is being diverted to the media (middle) layer and may result in patient death if not quickly attended. In the case where the diseased portion of the aorta needs to be replaced, one common surgical technique is to use a graft made of Dacron, a synthetic fabric. We investigate the response of a composite human aortic segment-Dacron graft structure subjected to blood flow using the three-dimensional fluid-structure-interaction (FSI) capability in Abaqus. We obtain stress and strain profiles in each of the three layers of the aortic walls as well as in the Dacron graft. Results are compared when elastic and hyperelastic models are used and when isotropy vs. anisotropy is assumed. The more complex case (hyperelastic-anisotropy) is represented by the Holzapfel-Gasser-Ogden (HGO) model which also accounts for the orientation of the fibers present in the tissues. The fluid flow is taken as Newtonian, incompressible, pulsatile and turbulent. The simulation show that for all the cases, the von Mises stress distribution at aorta-Dacron interface is well below the ultimate strength of the aorta. No significant change in radial displacement at the interface of the two materials due to blood flow is observed. Computation cost is also addressed and results show that the hyperelastic-anisotropic model takes about three times longer to run than the elastic isotropic case. Trade-off between accuracy and computational cost has to be weighted. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Usage of Bone Replacement Grafts in Periodontics and Oral Implantology and Their Current Levels of Clinical Evidence - A Systematic Assessment.

    PubMed

    Salem, Daliah; Natto, Zuhair; Elangovan, Satheesh; Karimbux, Nadeem

    2016-08-01

    The aim of this review is to evaluate the levels of clinical evidence for bone replacement grafts available in the United States for periodontics and oral implantology purposes. A search was performed using PubMed, the Cochrane Library, and Google Scholar for articles relating to the use of bone replacement grafts in implant and/or periodontics by two independent reviewers. Articles unrelated to the topic, not involving patients, not including abstracts, or in languages other than English were excluded. Selected articles were graded according to "levels of evidence" based on guidelines originally introduced by Wright et al. (2003). There was limited published peer-reviewed clinical literature available regarding US commercially available bone replacement grafts in periodontics and oral implantology. Of 144 bone replacement grafts available in the United States according to Avila-Ortiz et al. (2013), only 52 met the inclusion criteria. The majority of materials used were allografts (26 of 93 available in the United States), followed by alloplasts (15 of 30) and xenografts (11 of 21). Dental providers should be aware of the limited evidence that qualified for a strong rating supporting the clinical efficacy of these materials for periodontics and oral implantology purposes using the inclusion criteria selected in this study.

  13. AAA Foundation for Traffic Safety

    MedlinePlus

    ... of Top Deadly Mistakes Made by Teen Drivers -- AAA AAA: Road debris causes avoidable crashes, deaths Save the ... and 500 deaths! Foundation News Stay Tuned New AAA Foundation for Traffic Safety website coming Fall 2017 ...

  14. Efficacy of immediate replacement of cranial bone graft following drainage of intracranial empyema.

    PubMed

    Lajthia, Orgest; Chao, Jerry W; Mandelbaum, Max; Myseros, John S; Oluigbo, Chima; Magge, Suresh N; Zarella, Christopher S; Oh, Albert K; Rogers, Gary F; Keating, Robert F

    2018-06-22

    OBJECTIVE Intracranial empyema is a life-threatening condition associated with a high mortality rate and residual deleterious neurological effects if not diagnosed and managed promptly. The authors present their institutional experience with immediate reimplantation of the craniotomy flap and clarify the success of this method in terms of cranial integrity, risk of recurrent infection, and need for secondary procedures. METHODS A retrospective analysis of patients admitted for management of intracranial empyema during a 19-year period (1997-2016) identified 33 patients who underwent emergency drainage and decompression with a follow-up duration longer than 6 months, 23 of whom received immediate bone replacement. Medical records were analyzed for demographic information, extent and location of the infection, bone flap size, fixation method, need for further operative intervention, and duration of intravenous antibiotics. RESULTS The mean patient age at surgery was 8.7 ± 5.7 years and the infections were largely secondary to sinusitis (52.8%), with the most common location being the frontal/temporal region (61.3%). Operative intervention involved removal of a total of 31 bone flaps with a mean surface area of 22.8 ± 26.9 cm 2 . Nearly all (96.8%) of the bone flaps replaced at the time of the initial surgery were viable over the long term. Eighteen patients (78.3%) required a single craniotomy in conjunction with antibiotic therapy to address the infection, whereas the remaining 21.7% required more than 1 surgery. Partial bone flap resorption was noted in only 1 (3.2%) of the 31 successfully replaced bone flaps. This patient eventually had his bone flap removed and received a split-calvaria bone graft. Twenty-one patients (91.3%) received postoperative CT scans to evaluate bone integrity. The mean follow-up duration of the cohort was 43.9 ± 54.0 months. CONCLUSIONS The results of our investigation suggest that immediate replacement and stabilization of the bone

  15. [Ankle arthrodesis with interposition graft as a salvage procedure after failed total ankle replacement].

    PubMed

    Schill, Stephan

    2007-12-01

    Restoration of painless function to the lower limb by ankle fusion after failure of total ankle arthroplasty. Loose total ankle replacement. Severe ankle destruction and axial deviation in rheumatoid patients. Severe osteoarthritis in the subtalar and ankle joints. Infected total ankle replacement. Severe arterial occlusive disease of the affected extremity. Transfibular approach to the subtalar and ankle joints. Osteotomy and resection of the distal fibula 7-8 cm proximal to the tip of the lateral malleolus. Removal of the prosthetic components, synovectomy, and revitalization of the remaining bone surface. Removal of any residual articular cartilage from the subtalar joint surfaces. Determination of the extent of bone loss and defect filling with horizontally or vertically placed tricortical and cancellous bone graft from the resected fibula and, if necessary, from the ipsilateral anterior iliac crest. Tibiotalocalcaneal arthrodesis by retrograde insertion of a retrograde locking nail. Wound closure in layers. Split below-knee cast. Mobilization with below-knee cast without weight bearing for 6 weeks. Dynamic locking of the intramedullary nail. Partial weight bearing with a walker up to 20 kg for an additional 6 weeks. Gradual increase in weight bearing in accordance with radiologic evidence of consolidation. Fitted orthopedic shoe with rocker-bottom sole, and made to measure insoles. From January 2003 to September 2006, 15 patients with infected ankle prosthesis loosening (six Thompson-Richards prostheses, eight S.T.A.R. prostheses, and one Salto prosthesis) were treated. All patients underwent tibiotalocalcaneal interposition arthrodesis with femoral nailing in retrograde technique. The average AOFAS (American Orthopaedic Foot and Ankle Society) Score was 57.9 points (35-81 points) postoperatively. One patient developed a nonunion and revision surgery will have to be performed. Another patient with delayed wound healing and skin necrosis needed plastic surgery.

  16. AAAS: Politics. . . and Science

    ERIC Educational Resources Information Center

    Science News, 1978

    1978-01-01

    Reviews topics discussed during the American Association for the Advancement of Science (AAAS) meeting held in Washington, D.C. Topics included: the equal rights amendment, laetrile, nuclear radiation hazards, sociobiology, and various science topics. (SL)

  17. Multifunctional Mitochondrial AAA Proteases

    PubMed Central

    Glynn, Steven E.

    2017-01-01

    Mitochondria perform numerous functions necessary for the survival of eukaryotic cells. These activities are coordinated by a diverse complement of proteins encoded in both the nuclear and mitochondrial genomes that must be properly organized and maintained. Misregulation of mitochondrial proteostasis impairs organellar function and can result in the development of severe human diseases. ATP-driven AAA+ proteins play crucial roles in preserving mitochondrial activity by removing and remodeling protein molecules in accordance with the needs of the cell. Two mitochondrial AAA proteases, i-AAA and m-AAA, are anchored to either face of the mitochondrial inner membrane, where they engage and process an array of substrates to impact protein biogenesis, quality control, and the regulation of key metabolic pathways. The functionality of these proteases is extended through multiple substrate-dependent modes of action, including complete degradation, partial processing, or dislocation from the membrane without proteolysis. This review discusses recent advances made toward elucidating the mechanisms of substrate recognition, handling, and degradation that allow these versatile proteases to control diverse activities in this multifunctional organelle. PMID:28589125

  18. Multifunctional Mitochondrial AAA Proteases.

    PubMed

    Glynn, Steven E

    2017-01-01

    Mitochondria perform numerous functions necessary for the survival of eukaryotic cells. These activities are coordinated by a diverse complement of proteins encoded in both the nuclear and mitochondrial genomes that must be properly organized and maintained. Misregulation of mitochondrial proteostasis impairs organellar function and can result in the development of severe human diseases. ATP-driven AAA+ proteins play crucial roles in preserving mitochondrial activity by removing and remodeling protein molecules in accordance with the needs of the cell. Two mitochondrial AAA proteases, i-AAA and m-AAA, are anchored to either face of the mitochondrial inner membrane, where they engage and process an array of substrates to impact protein biogenesis, quality control, and the regulation of key metabolic pathways. The functionality of these proteases is extended through multiple substrate-dependent modes of action, including complete degradation, partial processing, or dislocation from the membrane without proteolysis. This review discusses recent advances made toward elucidating the mechanisms of substrate recognition, handling, and degradation that allow these versatile proteases to control diverse activities in this multifunctional organelle.

  19. The effect of placing a bone replacement graft in the gap at immediately placed implants: a randomized clinical trial.

    PubMed

    Sanz, Mariano; Lindhe, Jan; Alcaraz, Jaime; Sanz-Sanchez, Ignacio; Cecchinato, Denis

    2017-08-01

    To assess the added value of using a bone replacement graft in combination with immediate implants in reducing the bone dimensional changes occurring in the residual ridge. Randomized parallel controlled clinical trial to study the efficacy of grafting with demineralized bovine bone mineral with 10% collagen (DBBM-C) in the gap between the implant surface and the inner bone walls when the implants were immediately placed in the anterior maxilla. The changes between implant placement and 16 weeks later in the horizontal and vertical crestal bone changes in relation to the implant were evaluated through direct bone measurements using a periodontal probe. Mean changes were compared between the experimental and control sites using parametric statistics. A total of 86 implant sites in 86 subjects were included in the analysis (43 in the test group and 43 in the control group). The horizontal crest dimension underwent marked changes during healing mainly at the buccal aspect of the alveolar crest where this reduction amounted to 1.1 (29%) in the test group and 1.6 mm (38%) in the control group, being these statistically significant (P = 0.02). This outcome was even more pronounced at sites in the anterior maxilla and with thinner buccal bone plates. In conclusion, the results from this clinical trial demonstrated that placing a DBBM-C bone replacement graft significantly reduced the horizontal bone resorptive changes occurring in the buccal bone after the immediate implantation in fresh extraction sockets. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Cadaveric aorta implantation for aortic graft infection.

    PubMed

    Ali, Asad; Bahia, Sandeep S S; Ali, Tahir

    2016-01-01

    This case report describes a 73-year-old gentleman who underwent explantation of an infected prosthetic aorto-iliac graft and replacement with a cryopreserved thoracic and aorto-iliac allograft. The patient has been followed up a for more than a year after surgery and remains well. After elective tube graft repair of his abdominal aortic aneurysm (AAA) in 2003, he presented to our unit in 2012 in cardiac arrest as a result of a rupture of the distal graft suture line due to infection. After resuscitation he underwent aorto-bifemoral grafting using a cuff of the original aortic graft proximally. Distally the new graft was anastomosed to his common femoral arteries, with gentamicin beads left in situ. Post discharge the patient was kept under close surveillance with serial investigations including nuclear scanning, however it became apparent that his new graft was infected and that he would require aortic graft replacement, an operation with a mortality of at least 50%. The patient underwent the operation and findings confirmed a synthetic graft infection. This tube graft was explanted and a cryopreserved aorta was used to the refashion the abdominal aorta and its bifurcation. The operation required a return to theatre day one post operatively for a bleeding side branch, which was repaired. The patient went on to make a full recovery stepping down from the intensive therapy unit day 6 post operatively and went on to be discharged 32 days after his cryopreserved aorta implantation. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  1. A methodology for developing anisotropic AAA phantoms via additive manufacturing.

    PubMed

    Ruiz de Galarreta, Sergio; Antón, Raúl; Cazón, Aitor; Finol, Ender A

    2017-05-24

    An Abdominal Aortic Aneurysm (AAA) is a permanent focal dilatation of the abdominal aorta at least 1.5 times its normal diameter. The criterion of maximum diameter is still used in clinical practice, although numerical studies have demonstrated the importance of biomechanical factors for rupture risk assessment. AAA phantoms could be used for experimental validation of the numerical studies and for pre-intervention testing of endovascular grafts. We have applied multi-material 3D printing technology to manufacture idealized AAA phantoms with anisotropic mechanical behavior. Different composites were fabricated and the phantom specimens were characterized by biaxial tensile tests while using a constitutive model to fit the experimental data. One composite was chosen to manufacture the phantom based on having the same mechanical properties as those reported in the literature for human AAA tissue; the strain energy and anisotropic index were compared to make this choice. The materials for the matrix and fibers of the selected composite are, respectively, the digital materials FLX9940 and FLX9960 developed by Stratasys. The fiber proportion for the composite is equal to 0.15. The differences between the composite behavior and the AAA tissue are small, with a small difference in the strain energy (0.4%) and a maximum difference of 12.4% in the peak Green strain ratio. This work represents a step forward in the application of 3D printing technology for the manufacturing of AAA phantoms with anisotropic mechanical behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Replacement of the aortic root with a composite valve-graft conduit: risk factor analysis in 246 consecutive patients.

    PubMed

    Woldendorp, Kei; Starra, Eric; Seco, Michael; Hendel, P Nicholas; Jeremy, Richmond W; Wilson, Michael K; Vallely, Michael P; Bannon, Paul G

    2014-12-01

    Composite valve-graft (CVG) replacement of the aortic root is a well-studied and recognised treatment for various aortic root conditions, including valvular disease with associated aortopathy. There have been few previous studies of the procedure in large numbers in an Australian setting. From January 2006 to June 2013, 246 successive patients underwent CVG root replacements at our institution. Mean age was 56.8 years, 85.4% were male, and 87 had evidence of bicuspid aortic valve. Indications for operation included ascending aortic aneurysm in 222 patients, annuloaortic ectasia in 67 patients, and aortic dissection in 38 patients. The overall unit 30-day mortality was 5.7%, including: elective 30-day mortality of 2.2%, and emergent 30-day mortality of 17.2%. Statistically significant multivariate predictors of 30-day mortality were: acute aortic dissection (OR=20.07), peripheral vascular disease (OR=11.17), new ventricular tachycardia (OR=30.17), re-operation for bleeding (OR=14.42), concomitant mitral stenosis (OR=68.30), and cerebrovascular accident (OR=144.85). Low postoperative mortality in our series matches closely with results from similar sized international studies, demonstrating that this procedure can be performed with low risk in centres with sufficient experience in the operative procedure. Copyright © 2014 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.

  3. Assessment of Hemodynamic Conditions in the Aorta Following Root Replacement with Composite Valve-Conduit Graft.

    PubMed

    Cheng, Zhuo; Kidher, Emaddin; Jarral, Omar A; O'Regan, Declan P; Wood, Nigel B; Athanasiou, Thanos; Xu, Xiao Yun

    2016-05-01

    This paper presents the analysis of detailed hemodynamics in the aortas of four patients following replacement with a composite bio-prosthetic valve-conduit. Magnetic resonance image-based computational models were set up for each patient with boundary conditions comprising subject-specific three-dimensional inflow velocity profiles at the aortic root and central pressure waveform at the model outlet. Two normal subjects were also included for comparison. The purpose of the study was to investigate the effects of the valve-conduit on flow in the proximal and distal aorta. The results suggested that following the composite valve-conduit implantation, the vortical flow structure and hemodynamic parameters in the aorta were altered, with slightly reduced helical flow index, elevated wall shear stress and higher non-uniformity in wall shear compared to normal aortas. Inter-individual analysis revealed different hemodynamic conditions among the patients depending on the conduit configuration in the ascending aorta, which is a key factor in determining post-operative aortic flow. Introducing a natural curvature in the conduit to create a smooth transition between the conduit and native aorta may help prevent the occurrence of retrograde and recirculating flow in the aortic arch, which is particularly important when a large portion or the entire ascending aorta needs to be replaced.

  4. Rationale for one stage exchange of infected hip replacement using uncemented implants and antibiotic impregnated bone graft.

    PubMed

    Winkler, Heinz

    2009-09-04

    Infection of a total hip replacement (THR) is considered a devastating complication, necessitating its complete removal and thorough debridement of the site. It is undoubted that one stage exchange, if successful, would provide the best benefit both for the patient and the society. Still the fear of re-infection dominates the surgeons decisions and in the majority of cases directs them to multiple stage protocols. However, there is no scientifically based argument for that practice. Successful eradication of infection with two stage procedures is reported to average 80% to 98%. On the other hand a literature review of Jackson and Schmalzried (CORR 2000) summarizing the results of 1,299 infected hip replacements treated with direct exchange (almost exclusively using antibiotic loaded cement), reports of 1,077 (83%) having been successful. The comparable results suggest, that the major factor for a successful outcome with traditional approaches may be found in the quality of surgical debridement and dead space management. Failures in all protocols seem to be caused by small fragments of bacterial colonies remaining after debridement, whereas neither systemic antibiotics nor antibiotic loaded bone cement (PMMA) have been able to improve the situation significantly. Reasons for failure may be found in the limited sensitivity of traditional bacterial culturing and reduced antibiotic susceptibility of involved pathogens, especially considering biofilm formation. Whenever a new prosthesis is implanted into a previously infected site the surgeon must be aware of increased risk of failure, both in single or two stage revisions. Eventual removal therefore should be easy with low risk of additional damage to the bony substance. On the other hand it should also have potential of a good long term result in case of success. Cemented revisions generally show inferior long term results compared to uncemented techniques; the addition of antibiotics to cement reduces its

  5. Osteochondral graft from the pre-achilles area for replacement of articular surface defects

    NASA Astrophysics Data System (ADS)

    Kuznetsov, V. V.; Pahomov, I. A.; Prohorenko, V. M.; Sadovoy, M. A.; Korel, A. V.; Zaydman, A. M.; Repin, A. V.; Gudi, S. M.; Korochkin, S. B.

    2017-09-01

    We substantiate a new technique for obtaining osteochondral autograft to replace osteochondral defects resulting from various lesions of the talar trochlea by means of morphological examination of the following microslides: talar cartilage (cadaver material), cartilage portion of the pre-achilles zone of the calcaneum, lateral femoral condyle, and necrotic area of the talus. Examination of the specimens of the pre-achilles cartilage of the calcaneus revealed a large number of poorly differentiated chondroblasts in the homogeneously stained extracellular matrix; the presence of all zones (superficial zone, zone of columnar structures, and "tidemark"). This is indicative of structural and functional preservation of this cartilage, which therefore can be considered as an autograft material.

  6. Efficacy of a novel strategy for poststernotomy deep sternal infection after thoracic aorta replacement using a prosthetic graft.

    PubMed

    Kuriyama, Motone; Yoshida, Yukitaka; Ninomiya, Hitoshi; Yamamoto, Shin; Sasaguri, Shiro; Akita, Shinsuke; Mitsukawa, Nobuyuki

    2018-05-01

    Poststernotomy deep sternal wound infections are persistent and occasionally fatal, especially in cases involving prosthetic grafts, because of their complicated structure and virtual impossibility of removal. We aimed to verify the influence of cooperation with plastic surgeons and our novel strategy for treating deep sternal wound infection after aortic replacement on cardiovascular surgery outcomes. Nine hundred eighty-three consecutive patients were divided into two groups: an early group (2012-2013) and a late group (2014-2015). The late group had received cooperatively improved perioperative wound management: our novel strategy of deep sternal infection based on radical debridement and immediate reconstruction decided by reference to severities of the patient's general condition and widespread infection by early intervention of plastic surgeons. The groups were analysed retrospectively. Binary variables were analysed statistically with the Fisher exact test and continuous variables with the Mann-Whitney U test. Inter-group differences were assessed with the chi-square test. Twenty of 390 cases in the early group and 13 of 593 cases in the late group were associated with deep sternal infection. Morbidity rates of deep sternal wound infection and associated mortality rates 1 year after reconstruction surgery were significantly less (p <0.05 for both) in the late group. Intervention by plastic surgeons improved perioperative wound management outcomes. Our treatment strategy for deep sternal wound infection also reduced associated mortality rates. Facilities should consider the early inclusion of plastic surgeons in the treatment of patients undergoing aortic replacement to facilitate better outcomes. Copyright © 2018 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  7. NASA Airborne Astronomy Ambassadors (AAA)

    NASA Astrophysics Data System (ADS)

    Backman, D. E.; Harman, P. K.; Clark, C.

    2016-12-01

    NASA's Airborne Astronomy Ambassadors (AAA) is a three-part professional development (PD) program for high school physics and astronomy teachers. The AAA experience consists of: (1) blended-learning professional development composed of webinars, asynchronous content learning, and a series of hands-on workshops (2) a STEM immersion experience at NASA Armstrong Flight Research Center's B703 science research aircraft facility in Palmdale, California, and (3) ongoing participation in the AAA community of practice (CoP) connecting participants with astrophysics and planetary science Subject Matter Experts (SMEs). The SETI Institute (SI) is partnering with school districts in Santa Clara and Los Angeles Counties during the AAA program's "incubation" period, calendar years 2016 through 2018. AAAs will be selected by the school districts based on criteria developed during spring 2016 focus group meetings led by the program's external evaluator, WestEd.. Teachers with 3+ years teaching experience who are assigned to teach at least 2 sections in any combination of the high school courses Physics (non-AP), Physics of the Universe (California integrated model), Astronomy, or Earth & Space Sciences are eligible. Partner districts will select at least 48 eligible applicants with SI oversight. WestEd will randomly assign selected AAAs to group A or group B. Group A will complete PD in January - June of 2017 and then participate in SOFIA science flights during fall 2017 (SOFIA Cycle 5). Group B will act as a control during the 2017-18 school year. Group B will then complete PD in January - June of 2018 and participate in SOFIA science flights in fall 2018 (Cycle 6). Under the current plan, opportunities for additional districts to seek AAA partnerships with SI will be offered in 2018 or 2019. A nominal two-week AAA curriculum component will be developed by SI for classroom delivery that will be aligned with selected California Draft Science Framework Disciplinary Core Ideas

  8. Identifying patients with AAA with the highest risk following endovascular repair.

    PubMed

    Cadili, Ali; Turnbull, Robert; Hervas-Malo, Marilou; Ghosh, Sunita; Chyczij, Harold

    2012-08-01

    It has been demonstrated that endovascular repair of arterial disease results in reduced perioperative morbidity and mortality compared to open surgical repair. The rates of complications and need for reinterventions, however, have been found to be higher than that in open repair. The purpose of this study was to identify the predictors of endograft complications and mortality in patients undergoing endovascular abdominal aortic aneurysm (AAA) repair; specifically, our aim was to identify a subset of patients with AAA whose risk of periprocedure mortality was so high that they should not be offered endovascular repair. We undertook a prospective review of patients with AAA receiving endovascular therapy at a single institution. Collected variables included age, gender, date of procedure, indication for procedure, size of aneurysm (where applicable), type of endograft used, presence of rupture, American Society of Anesthesiologists (ASA) class, major medical comorbidities, type of anesthesia (general, epidural, or local), length of intensive care unit (ICU) stay, and length of hospital stay. These factors were correlated with the study outcomes (overall mortality, graft complications, morbidity, and reintervention) using univariate and multivariate logistic regression. A total of 199 patients underwent endovascular AAA repair during the study period. The ICU stay, again, was significantly correlated with the primary outcomes (death and graft complications). In addition, length of hospital stay greater than 3 days, also emerged as a statistically significant predictor of graft complications in this subgroup (P = .024). Survival analysis for patients with AAA revealed that age over 85 years and ICU stay were predictive of decreased survival. Statistical analysis for other subgroups of patients (inflammatory AAA or dissection) was not performed due to the small numbers in these subgroups. Patients with AAA greater than 85 years of age are at a greater risk of mortality

  9. Assessment of the accuracy of AortaScan for detection of abdominal aortic aneurysm (AAA).

    PubMed

    Abbas, A; Smith, A; Cecelja, M; Waltham, M

    2012-02-01

    AortaScan AMI 9700 is a portable 3D ultrasound device that automatically measures the maximum diameter of the abdominal aorta without the need for a trained sonographer. It is designed to rapidly diagnose or exclude an AAA and may have particular use in screening programs. Our objective was to determine its accuracy to detect AAA. Subjects from our AAA screening and surveillance programs were examined. The aorta was scanned using the AortaScan and computed tomography (CT). Ninety-one subjects underwent imaging (44 AAA on conventional ultrasound surveillance and 47 controls). The largest measurement obtained by AortaScan was compared against the CT-aortic measurement. The mean aortic diameter was 2.8 cm. The CT scan confirmed the diagnosis of AAA in 43 subjects. There was one false positive measurement on conventional ultrasound. AortaScan missed the diagnosis of AAA in eight subjects. There were thirteen false positive measurements. The sensitivity, specificity, positive and negative predictive values were 81%, 72%, 72% and 81% respectively. A device to detect AAA without the need for a trained operator would have potential in a community-based screening programme. The AortaScan, however, lacks adequate sensitivity and significant technical improvement is necessary before it could be considered a replacement for trained screening personnel. Copyright © 2011 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  10. Catheter-based tricuspid valve replacement: first experimental data of a newly designed bileaflet stent graft prosthesis.

    PubMed

    Lausberg, Henning F; Gryszkiewicz, Rafal; Kuetting, Maximilian; Baumgaertner, Moritz; Centola, Marcos; Wendel, Hans-Peter; Nowak-Machen, Martina; Schibilsky, David; Kruger, Tobias; Schlensak, Christian

    2017-07-01

    Moderate or severe degree tricuspid valve regurgitation (TVR) is associated with high rates of morbidity and mortality. Surgical correction as the only therapeutic option offers unsatisfactory results. Recently, several interventional procedures have been introduced clinically in a limited cohort. We present our initial experiments with an innovative interventional valved stent graft for treatment of TVR. A newly designed porcine pericardium-covered nitinol stent graft with a lateral bicuspid valve was adapted to size in a cadaver study. After haemodynamic testing in an ex vivo perfusion setup, vascular access, valve delivery and function were investigated in an ovine animal model ( n  = 7). The device was implanted successfully in all animals. Vascular access was established surgically via the femoral vein without any vascular complications. Angiography demonstrated the correct position of the device with proper sealing of both venae cavae in 6 animals. In 1 extremely large animal, the position of the device was considered too cranial but still acceptable. Correct valve function was verified in all animals by both angiography and echocardiography. There were no persistent arrhythmias other than during valve implant. All animals survived the implant procedure and were sacrificed electively. This study demonstrated that this new valved stent graft could be delivered safely with correct positioning and valve function in this ovine model. Further long-term studies in animals implanted with the device after creation of tricuspid regurgitation are necessary to prove the haemodynamic benefit of this procedure. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  11. Prevalence of abdominal aortic aneurysm (AAA) in a population undergoing computed tomography colonography in Canterbury, New Zealand.

    PubMed

    Khashram, M; Jones, G T; Roake, J A

    2015-08-01

    There is compelling level 1 evidence in support of screening men for abdominal aortic aneurysm (AAA) to reduce AAA mortality. However, New Zealand (NZ) lacks data on AAA prevalence, and national screening has not been implemented. The aim of this study was to determine the prevalence of AAA in a population undergoing a computed tomography colonography (CTC) for gastrointestinal symptoms. This was an observational study; all consecutive CTCs performed in three regions of the South Island of NZ over a 4 year period were reviewed. Data on abdominal and thoracic aorta diameters ≥30 mm, and iliac and femoral aneurysms ≥20 mm were recorded. Previous aortic surgical grafts or endovascular stents were also documented. Demographics, survival, and AAA related outcomes were collected and used for analysis. Included were 4,893 scans on 4,644 patients (1,933 men [41.6%], 2,711 women [58.4%]) with a median age of 69.3 years (range 17.0-97.0 years). There were 309 scans on 289 patients (75.4% men) who had either an aneurysm or a previous aortic graft with a median age of 79.6 years (range 57.0-96.0 years). Of these, 223 had a native AAA ≥30 mm. The prevalence of AAA rose with age from 1.3% in men aged 55-64 years, to 9.1% in 65-74 year olds, 16.8% in 75-84 year olds, and 22.0% in ≥85 year olds. The corresponding figures in women were 0.4%, 2%, 3.9%, and 6.2%, respectively. In this observational study, the prevalence of AAA was high and warrants further evaluation. The results acquired help to define a population that may benefit from a national AAA screening programme. Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  12. AAA-ATPases in Protein Degradation

    PubMed Central

    Yedidi, Ravikiran S.; Wendler, Petra; Enenkel, Cordula

    2017-01-01

    Proteolytic machineries containing multisubunit protease complexes and AAA-ATPases play a key role in protein quality control and the regulation of protein homeostasis. In these protein degradation machineries, the proteolytically active sites are formed by either threonines or serines which are buried inside interior cavities of cylinder-shaped complexes. In eukaryotic cells, the proteasome is the most prominent protease complex harboring AAA-ATPases. To degrade protein substrates, the gates of the axial entry ports of the protease need to be open. Gate opening is accomplished by AAA-ATPases, which form a hexameric ring flanking the entry ports of the protease. Protein substrates with unstructured domains can loop into the entry ports without the assistance of AAA-ATPases. However, folded proteins require the action of AAA-ATPases to unveil an unstructured terminus or domain. Cycles of ATP binding/hydrolysis fuel the unfolding of protein substrates which are gripped by loops lining up the central pore of the AAA-ATPase ring. The AAA-ATPases pull on the unfolded polypeptide chain for translocation into the proteolytic cavity of the protease. Conformational changes within the AAA-ATPase ring and the adjacent protease chamber create a peristaltic movement for substrate degradation. The review focuses on new technologies toward the understanding of the function and structure of AAA-ATPases to achieve substrate recognition, unfolding and translocation into proteasomes in yeast and mammalian cells and into proteasome-equivalent proteases in bacteria and archaea. PMID:28676851

  13. AAA-ATPases in Protein Degradation.

    PubMed

    Yedidi, Ravikiran S; Wendler, Petra; Enenkel, Cordula

    2017-01-01

    Proteolytic machineries containing multisubunit protease complexes and AAA-ATPases play a key role in protein quality control and the regulation of protein homeostasis. In these protein degradation machineries, the proteolytically active sites are formed by either threonines or serines which are buried inside interior cavities of cylinder-shaped complexes. In eukaryotic cells, the proteasome is the most prominent protease complex harboring AAA-ATPases. To degrade protein substrates, the gates of the axial entry ports of the protease need to be open. Gate opening is accomplished by AAA-ATPases, which form a hexameric ring flanking the entry ports of the protease. Protein substrates with unstructured domains can loop into the entry ports without the assistance of AAA-ATPases. However, folded proteins require the action of AAA-ATPases to unveil an unstructured terminus or domain. Cycles of ATP binding/hydrolysis fuel the unfolding of protein substrates which are gripped by loops lining up the central pore of the AAA-ATPase ring. The AAA-ATPases pull on the unfolded polypeptide chain for translocation into the proteolytic cavity of the protease. Conformational changes within the AAA-ATPase ring and the adjacent protease chamber create a peristaltic movement for substrate degradation. The review focuses on new technologies toward the understanding of the function and structure of AAA-ATPases to achieve substrate recognition, unfolding and translocation into proteasomes in yeast and mammalian cells and into proteasome-equivalent proteases in bacteria and archaea.

  14. Molecular insights into the m-AAA protease-mediated dislocation of transmembrane helices in the mitochondrial inner membrane.

    PubMed

    Lee, Seoeun; Lee, Hunsang; Yoo, Suji; Kim, Hyun

    2017-12-08

    Protein complexes involved in respiration, ATP synthesis, and protein import reside in the mitochondrial inner membrane; thus, proper regulation of these proteins is essential for cell viability. The m -AAA protease, a conserved hetero-hexameric AAA (ATPase associated with diverse cellular activities) protease, composed of the Yta10 and Yta12 proteins, regulates mitochondrial proteostasis by mediating protein maturation and degradation. It also recognizes and mediates the dislocation of membrane-embedded substrates, including foreign transmembrane (TM) segments, but the molecular mechanism involved in these processes remains elusive. This study investigated the role of the TM domains in the m -AAA protease by systematic replacement of one TM domain at a time in yeast. Our data indicated that replacement of the Yta10 TM2 domain abolishes membrane dislocation for only a subset of substrates, whereas replacement of the Yta12 TM2 domain impairs membrane dislocation for all tested substrates, suggesting different roles of the TM domains in each m -AAA protease subunit. Furthermore, m -AAA protease-mediated membrane dislocation was impaired in the presence of a large downstream hydrophilic moiety in a membrane substrate. This finding suggested that the m -AAA protease cannot dislocate large hydrophilic domains across the membrane, indicating that the membrane dislocation probably occurs in a lipid environment. In summary, this study highlights previously underappreciated biological roles of TM domains of the m -AAA proteases in mediating the recognition and dislocation of membrane-embedded substrates. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Risk of abdominal aortic aneurysm (AAA) among male and female relatives of AAA patients.

    PubMed

    van de Luijtgaarden, Koen M; Rouwet, Ellen V; Hoeks, Sanne E; Stolker, Robert J; Verhagen, Hence Jm; Majoor-Krakauer, Danielle

    2017-04-01

    Sex affects the presentation, treatment, and outcomes of abdominal aortic aneurysm (AAA). Although AAAs are less prevalent in women, at least in the general population, women with an AAA have a poorer prognosis in comparison to men. Sex differences in the genetic predisposition for aneurysm disease remain to be established. In this study we investigated the familial risk of AAA for women compared to men. All living AAA patients included in a 2004-2012 prospective database were invited to the multidisciplinary vascular/genetics outpatient clinic between 2009 and 2012 for assessment of family history using detailed questionnaires. AAA risk for male and female relatives was calculated separately and stratified by sex of the AAA patients. Families of 568 AAA patients were investigated and 22.5% of the patients had at least one affected relative. Female relatives had a 2.8-fold and male relatives had a 1.7-fold higher risk than the estimated sex-specific population risk. Relatives of female AAA patients had a higher aneurysm risk than relatives of male patients (9.0 vs 5.9%, p = 0.022), corresponding to 5.5- and 2.0-fold increases in aneurysm risk in the female and male relatives, respectively. The risk for aortic aneurysm in relatives of AAA patients is higher than expected from population risk. The excess risk is highest for the female relatives of AAA patients and for the relatives of female AAA patients. These findings endorse targeted AAA family screening for female and male relatives of all AAA patients.

  16. Engineering Silicone Rubbers for In vitro Studies: Creating AAA Models and ILT Analogues with Physiological Properties

    PubMed Central

    Corbett, T.J.; Doyle, B.J.; Callanan, A.; Walsh, M.T.; McGloughlin, T.M

    2010-01-01

    in the sac of our models could have an effect on the compliance of the model neck. Conclusions Ideal AAA models with physiological properties were manufactured. The behaviour of these models due to pressurisation was predicted using FEA, validating this technique for the future design of realistic, physiological AAA models. Addition of ILT analogues in the aneurysm sac was shown to affect neck behaviour. This could have implications for endovascular AAA repair due to the importance of the neck for stent-graft fixation. PMID:20524746

  17. Electron cryomicroscopy structure of a membrane-anchored mitochondrial AAA protease.

    PubMed

    Lee, Sukyeong; Augustin, Steffen; Tatsuta, Takashi; Gerdes, Florian; Langer, Thomas; Tsai, Francis T F

    2011-02-11

    FtsH-related AAA proteases are conserved membrane-anchored, ATP-dependent molecular machines, which mediate the processing and turnover of soluble and membrane-embedded proteins in eubacteria, mitochondria, and chloroplasts. Homo- and hetero-oligomeric proteolytic complexes exist, which are composed of homologous subunits harboring an ATPase domain of the AAA family and an H41 metallopeptidase domain. Mutations in subunits of mitochondrial m-AAA proteases have been associated with different neurodegenerative disorders in human, raising questions on the functional differences between homo- and hetero-oligomeric AAA proteases. Here, we have analyzed the hetero-oligomeric yeast m-AAA protease composed of homologous Yta10 and Yta12 subunits. We combined genetic and structural approaches to define the molecular determinants for oligomer assembly and to assess functional similarities between Yta10 and Yta12. We demonstrate that replacement of only two amino acid residues within the metallopeptidase domain of Yta12 allows its assembly into homo-oligomeric complexes. To provide a molecular explanation, we determined the 12 Å resolution structure of the intact yeast m-AAA protease with its transmembrane domains by electron cryomicroscopy (cryo-EM) and atomic structure fitting. The full-length m-AAA protease has a bipartite structure and is a hexamer in solution. We found that residues in Yta12, which facilitate homo-oligomerization when mutated, are located at the interface between neighboring protomers in the hexamer ring. Notably, the transmembrane and intermembrane space domains are separated from the main body, creating a passage on the matrix side, which is wide enough to accommodate unfolded but not folded polypeptides. These results suggest a mechanism regarding how proteins are recognized and degraded by m-AAA proteases.

  18. Valve-Sparing Root Replacement Compared With Composite Valve Graft Procedures in Patients With Aortic Root Dilation.

    PubMed

    Ouzounian, Maral; Rao, Vivek; Manlhiot, Cedric; Abraham, Nachum; David, Carolyn; Feindel, Christopher M; David, Tirone E

    2016-10-25

    Although aortic valve-sparing (AVS) operations are established alternatives to composite valve graft (CVG) procedures for patients with aortic root aneurysms, comparative long-term outcomes are lacking. This study sought to compare the results of patients undergoing AVS procedures with those undergoing CVG operations. From 1990 to 2010, a total of 616 patients age <70 years and without aortic stenosis underwent elective aortic root surgery (AVS, n = 253; CVG with a bioprosthesis [bio-CVG], n = 180; CVG with a mechanical prosthesis [m-CVG], n = 183). A propensity score was used as a covariate to adjust for unbalanced variables in group comparisons. Mean age was 46 ± 14 years, 83.3% were male, and mean follow-up was 9.8 ± 5.3 years. Patients undergoing AVS had higher rates of Marfan syndrome and lower rates of bicuspid aortic valve than those undergoing bio-CVG or m-CVG procedures. In-hospital mortality (0.3%) and stroke rate (1.3%) were similar among groups. After adjusting for clinical covariates, both bio-CVG and m-CVG procedures were associated with increased long-term major adverse valve-related events compared with patients undergoing AVS (hazard ratio [HR]: 3.4, p = 0.005; and HR: 5.2, p < 0.001, respectively). They were also associated with increased cardiac mortality (HR: 7.0, p = 0.001; and HR: 6.4, p = 0.003). Furthermore, bio-CVG procedures were associated with increased risk of reoperations (HR: 6.9; p = 0.003), and m-CVG procedures were associated with increased risk of anticoagulant-related hemorrhage (HR: 5.6; p = 0.008) compared with AVS procedures. This comparative study showed that AVS procedures were associated with reduced cardiac mortality and valve-related complications when compared with bio-CVG and m-CVG. AVS is the treatment of choice for young patients with aortic root aneurysm and normal or near-normal aortic cusps. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  19. Approaches to Peripheral Nerve Repair: Generations of Biomaterial Conduits Yielding to Replacing Autologous Nerve Grafts in Craniomaxillofacial Surgery

    PubMed Central

    Knipfer, Christian; Hadlock, Tessa

    2016-01-01

    Peripheral nerve injury is a common clinical entity, which may arise due to traumatic, tumorous, or even iatrogenic injury in craniomaxillofacial surgery. Despite advances in biomaterials and techniques over the past several decades, reconstruction of nerve gaps remains a challenge. Autografts are the gold standard for nerve reconstruction. Using autografts, there is donor site morbidity, subsequent sensory deficit, and potential for neuroma development and infection. Moreover, the need for a second surgical site and limited availability of donor nerves remain a challenge. Thus, increasing efforts have been directed to develop artificial nerve guidance conduits (ANCs) as new methods to replace autografts in the future. Various synthetic conduit materials have been tested in vitro and in vivo, and several first- and second-generation conduits are FDA approved and available for purchase, while third-generation conduits still remain in experimental stages. This paper reviews the current treatment options, summarizes the published literature, and assesses future prospects for the repair of peripheral nerve injury in craniomaxillofacial surgery with a particular focus on facial nerve regeneration. PMID:27556032

  20. Vascular replacement using a layered elastin-collagen vascular graft in a porcine model: one week patency versus one month occlusion

    PubMed Central

    Koens, M J W; Krasznai, A G; Hanssen, A E J; Hendriks, T; Praster, R; Daamen, W F; van der Vliet, J A; van Kuppevelt, T H

    2015-01-01

    abstract A persistent clinical demand exists for a suitable arterial prosthesis. In this study, a vascular conduit mimicking the native 3-layered artery, and constructed from the extracellular matrix proteins type I collagen and elastin, was evaluated for its performance as a blood vessel equivalent. A tubular 3-layered graft (elastin-collagen-collagen) was prepared using highly purified type I collagen fibrils and elastin fibers, resembling the 3-layered native blood vessel architecture. The vascular graft was crosslinked and heparinised (37 ± 4 μg heparin/mg graft), and evaluated as a vascular graft using a porcine bilateral iliac artery model. An intra-animal comparison with clinically-used heparinised ePTFE (Propaten®) was made. Analyses included biochemical characterization, duplex scanning, (immuno)histochemistry and scanning electron microscopy. The tubular graft was easy to handle with adequate suturability. Implantation resulted in pulsating grafts without leakage. One week after implantation, both ePTFE and the natural acellular graft had 100% patencies on duplex scanning. Grafts were partially endothelialised (Von Willebrand-positive endothelium with a laminin-positive basal membrane layer). After one month, layered thrombi were found in the natural (4/4) and ePTFE graft (1/4), resulting in occlusion which in case of the natural graft is likely due to the porosity of the inner elastin layer. In vivo application of a molecularly-defined tubular graft, based on nature's matrix proteins, for vascular surgery is feasible. PMID:26060888

  1. Aortic valve replacement with or without coronary artery bypass graft surgery: the risk of surgery in patients > or =80 years old.

    PubMed

    Maslow, Andrew; Casey, Paula; Poppas, Athena; Schwartz, Carl; Singh, Arun

    2010-02-01

    The purpose of this study was to evaluate the outcomes for elderly (> or =80 years) patients undergoing aortic valve replacement (AVR) with or without coronary artery bypass graft surgery (AVR/CABG). The authors hypothesized that the mortalities of AVR and AVR/CABG are lower than that predicted by published risk scores. A retrospective analysis of data from a single-hospital database. Single tertiary care, private practice. Consecutive patients undergoing AVR or AVR/CABG. Two hundred sixty-one elderly (> or =80 years) patients undergoing isolated AVR (145) or AVR/CABG (116) were evaluated. The majority (94.6%) underwent AVR for aortic valve stenosis. Outcomes were recorded and compared between the 2 surgical procedures with predicted mortalities based on published risk assessment scoring systems. The overall short-term mortality for the elderly group was 6.1% (AVR 5.5% and AVR/CABG 6.9%). The median long-term survival was 6.8 years. There were no significant differences in either morbidity or mortality between the AVR and AVR/CABG groups. Although predicted mortalities were similar for each surgical procedure, they overestimated observed outcome by up to 4-fold. Short- and long-term mortality was low for this group of elderly patients undergoing AVR or AVR/CABG and not significantly different between the 2 surgical groups. Predicted outcomes were worse than that observed, consistent with the hypothesis, and supportive of a more aggressive surgical treatment for aortic valve disease in the elderly patient. Copyright 2010 Elsevier Inc. All rights reserved.

  2. Transcatheter Versus Surgical Aortic Valve Replacement in Patients With Prior Coronary Artery Bypass Grafting: Trends in Utilization and Propensity-Matched Analysis of In-Hospital Outcomes.

    PubMed

    Gupta, Tanush; Khera, Sahil; Kolte, Dhaval; Goel, Kashish; Kalra, Ankur; Villablanca, Pedro A; Aronow, Herbert D; Abbott, J Dawn; Fonarow, Gregg C; Taub, Cynthia C; Kleiman, Neal S; Weisz, Giora; Inglessis, Ignacio; Elmariah, Sammy; Rihal, Charanjit S; Garcia, Mario J; Bhatt, Deepak L

    2018-04-01

    A significant proportion of patients requiring aortic valve replacement (AVR) have undergone prior coronary artery bypass grafting (CABG). Reoperative heart surgery is associated with increased risk. Data on relative utilization and comparative outcomes of transcatheter (TAVR) versus surgical AVR (SAVR) in patients with prior CABG are limited. We queried the 2012 to 2014 National Inpatient Sample databases to identify isolated AVR hospitalizations in adults with prior CABG. In-hospital outcomes of TAVR versus SAVR were compared using propensity-matched analysis. Of 147 395 AVRs, 15 055 (10.2%) were in patients with prior CABG. The number of TAVRs in patients with prior CABG increased from 1615 in 2012 to 4400 in 2014, whereas the number of SAVRs decreased from 2285 to 1895 ( P trend <0.001). There were 3880 records in each group in the matched cohort. Compared with SAVR, TAVR was associated with similar in-hospital mortality (2.3% versus 2.4%; P =0.71) but lower incidence of myocardial infarction (1.5% versus 3.4%; P <0.001), stroke (1.4% versus 2.7%; P <0.001), bleeding complications (10.6% versus 24.6%; P <0.001), and acute kidney injury (16.2% versus 19.3%; P <0.001). Requirement for prior permanent pacemaker was higher in the TAVR cohort, whereas the incidence of vascular complications and acute kidney injury requiring dialysis was similar in the 2 groups. Average length of stay was shorter in patients undergoing TAVR. TAVR is being increasingly used as the preferred modality of AVR in patients with prior CABG. Compared with SAVR, TAVR is associated with similar in-hospital mortality but lower rates of in-hospital complications in this important subset of patients. © 2018 American Heart Association, Inc.

  3. A contemporary cost analysis of postoperative morbidity after coronary artery bypass grafting with and without concomitant aortic valve replacement to improve patient quality and cost-effective care.

    PubMed

    LaPar, Damien J; Crosby, Ivan K; Rich, Jeffrey B; Fonner, Edwin; Kron, Irving L; Ailawadi, Gorav; Speir, Alan M

    2013-11-01

    The financial burden of postoperative morbidity after cardiac operations remains ill defined. This study evaluated the costs associated with the performance of coronary artery bypass grafting (CABG) with and without aortic valve replacement (AVR) and determined the incremental costs associated with major postoperative complications. A total of 65,534 regional patients undergoing CABG (n = 55,167) ± AVR (n = 10,367) were evaluated from 2001 to 2011. Patient-related, hospital-related, and procedure-related cost data were analyzed by use of Medicare-based cost reports. Hierarchical multivariable regression modeling was used to estimate risk-adjusted incremental cost differences in postoperative complications. The mean age was 64 years, and women accounted for 31% of patients. CABG + AVR patients had higher rates of overall complication (40% vs 35%, p < 0.001) and operative mortality (5% vs 3%, p < 0.001) than did CABG patients. CABG + AVR patients also accrued increased median postoperative lengths of stay (7 vs 5 days, p < 0.001) and total costs ($26,527 vs $24,475, p < 0.001). After mortality risk adjustment, significant positive relationships existed between total costs and major postoperative complications. Interestingly, the highest incremental costs among CABG patients included newly instituted hemodialysis ($71,833), deep sternal wound infection ($56,003), and pneumonia ($50,025). Among CABG + AVR patients, these complications along with perioperative myocardial infarction ($68,917) dominated costs. Postoperative complications after CABG ± AVR are associated with significantly increased incremental costs. The most costly complications include newly instituted hemodialysis, infectious complications, and perioperative myocardial infarction. Identification of the most common and the most costly complications provides opportunities to target improvement in patient quality and the delivery of cost-effective care. Copyright © 2013 The Society of Thoracic Surgeons

  4. Concomitant coronary artery bypass graft and aortic and mitral valve replacement for rheumatic heart disease: short- and mid-term outcomes.

    PubMed

    Davarpasand, Tahereh; Hosseinsabet, Ali; Jalali, Arash

    2015-09-01

    It has been reported that the short-term mortality of concomitant aortic and mitral valve replacement (AVR and MVR) is considerable and concomitant coronary artery bypass graft (CABG) has adverse effects on the survival of patients with valve replacement surgery. We summarize the short- and mid-term outcome after concomitant CABG, AVR and MVR in our centre. Between 2003 and 2013, 103 patients (68 males, 35 females, age: 60.1 ± 10.1 years) underwent CABG, AVR and MVR for rheumatic heart disease (RHD) and coronary artery disease (CAD). The median follow-up was 47.6 months. Most of the patients were asymptomatic at rest. We analysed demographic, clinical and operative data of patients to define independent predictors of overall survival, cardiac event-free survival as well as cardiac death. The rate of 30-day survival was 93% (n = 96). The corresponding rates of overall survival and cardiac event-free survival and the cumulative incidence rate of cardiac death at 1 year were 80.2, 77.3 and 10.9%; the same at 4 years were 73.7, 64.6 and 15.8%. The corresponding freedom rates from anticoagulation-associated major haemorrhage; a composite of major bleeding events, thromboemboli and valvular thrombosis; cardiac rehospitalization; major adverse valve-associated events; and significant malfunction of the prosthetic valve were 96.2, 95.3, 94.7, 81.6 and 97.7% at 1 year. The corresponding freedom rates from anticoagulation-associated major haemorrhage; a composite of major bleeding events, thromboemboli and valvular thrombosis; cardiac rehospitalization; major adverse valve-associated events; and significant malfunction of the prosthetic valve were 93.5, 91.0, 91.4, 73.5 and 95.5% at 4 years. The independent predictors of overall survival were age, cigarette smoking, chronic kidney diseases and balloon pump insertion. The independent predictors of cardiac event-free survival were age and previous myocardial infarction, while age, cigarette smoking, history of cerebrovascular

  5. Genetic analysis of abdominal aortic aneurysms (AAA)

    SciTech Connect

    St. Jean, P.L.; Hart, B.K.; Zhang, X.C.

    1994-09-01

    The association between AAA and gender, smoking (SM), hypertension (HTN) and inguinal herniation (IH) was examined in 141 AAA probands and 139 of their 1st degree relatives with aortic exam (36 affected, 103 unaffected). There was no significant difference between age at diagnosis of affecteds and age at exam of unaffecteds. Of 181 males, 142 had AAA; of 99 females, 35 had AAA. Using log-linear modeling AAA was significantly associated at the 5% level with gender, SM and HTN but not IH. The association of AAA with SM and HTN held when males and females were analyzed separately. HTN wasmore » -1.5 times more common in both affected males and females, while SM was 1.5 and 2 times more common in affected males and females, respectively. Tests of association and linkage analyses were performed with relevant candidate genes: 3 COL3A1 polymorphisms (C/T, ALA/THR, AvaII), 2 ELN polymorphisms (SER/GLY, (CA)n), FBN1(TAAA)n, 2 APOB polymorphisms (Xbal,Ins/Del), CLB4B (CA)n, PI and markers D1S243 (CA)n, HPR (CA)n and MFD23(CA)n. The loci were genotyped in > 100 AAA probands and > 95 normal controls. No statistically significant evidence of association at the 5% level was obtained for any of the loci using chi-square test of association. 28 families with 2 or more affecteds were analyzed using the affected pedigree member method (APM) and lod-score analyses. There was no evidence for linkage with any loci using APM. Lod-score analysis under an autosomal recessive model resulted in excluding linkage (lod score < -2) of all loci to AAA at {theta}=0.0. Under an autosomal dominant model, linkage was excluded at {theta}=0.0 to ELN, APOB, CLG4B, D1S243, HPR and MFD23. The various genes previously proposed in AAA pathogenesis are neither associated nor casually related in our study population.« less

  6. Pathophysiology of AAA: heredity vs environment.

    PubMed

    Björck, Martin; Wanhainen, Anders

    2013-01-01

    Abdominal aortic aneurysm (AAA) has a complex pathophysiology, in which both environmental and genetic factors play important roles, the most important being smoking. The recently reported falling prevalence rates of AAA in northern Europe and Australia/New Zeeland are largely explained by healthier smoking habits. Dietary factors and obesity, in particular abdominal obesity, are also of importance. A family history of AAA among first-degree relatives is present in approximately 13% of incident cases. The probability that a monozygotic twin of a person with an AAA has the disease is 24%, 71 times higher than that for a monozygotic twin of a person without AAA. Approximately 1000 SNPs in 100 candidate genes have been studied, and three genome-wide association studies were published, identifying different diverse weak associations. An example of interaction between environmental and genetic factors is the effect of cholesterol, where genetic and dietary factors affect levels of both HDL and LDL. True epigenetic studies have not yet been published. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Updates on AAA screening and surveillance

    PubMed

    Theivendran, Mayo; Chuen, Jason

    2018-05-01

    Screening and diagnostic surveillance of latent conditions have a profound impact on public healthcare expenditure and clinical outcomes. Abdominal aortic aneurysm (AAA) remains one of the hallmark pathologies in vascular surgery and an area of intense research interest. This article is the second of two that will outline current areas of controversy and research in AAA disease in order to support a more detailed understanding of issues in managing patients with this condition, and inform the development of Australasian clinical guidelines and health policy. Screening and surveillance of AAA should be evidence-based and follow clinical guidelines; however, advances in treatment technology and epidemiological data have influenced results. Goals of care and cost‑effectiveness should play central parts in screening and surveillance strategies.

  8. LMIP/AAA: Local Authentication, Authorization and Accounting (AAA) Protocol for Mobile IP

    NASA Astrophysics Data System (ADS)

    Chenait, Manel

    Mobile IP represents a simple and scalable global mobility solution. However, it inhibits various vulnerabilities to malicious attacks and, therefore, requires the integration of appropriate security services. In this paper, we discuss two authentication schemes suggested for Mobile IP: standard authentication and Mobile IP/AAA authentication. In order to provide Mobile IP roaming services including identity verication, we propose an improvement to Mobile/AAA authentication scheme by applying a local politic key management in each domain, hence we reduce hando latency by avoiding the involvement of AAA infrastructure during mobile node roaming.

  9. Skin graft

    MedlinePlus

    ... that need skin grafts to heal Venous ulcers, pressure ulcers , or diabetic ulcers that do not heal Very ... graft; Full thickness skin graft Patient Instructions Preventing pressure ulcers Surgical wound care - open Images Skin graft Skin ...

  10. The Effects of Preoperative Volume Replacement in Diabetic Patients Undergoing Coronary Artery Bypass Grafting Surgery: Protocol for a Randomized Controlled Trial (VeRDiCT Trial)

    PubMed Central

    Clout, Madeleine; Harris, Tracy; Rogers, Chris; Culliford, Lucy; Taylor, Jodi; Angelini, Gianni; Narayan, Pradeep; Reeves, Barnaby; Hillier, James; Ashton, Kate; Sarkar, Kunal

    2017-01-01

    Background Diabetes mellitus is a major risk factor for prolonged hospital stays, renal failure, and mortality in patients having coronary artery bypass grafting (CABG). Complications pose a serious threat to patients and prolong intensive care and hospital stays. Low glomerular filtration rate (GFR) due to existing renal impairment or volume depletion may exacerbate acute renal impairment/failure in these patients. Preoperative volume replacement therapy (VRT) is reported to increase the GFR and we hypothesize that VRT will reduce renal impairment and related complications in diabetic patients. Objective The objective of this study is to establish the efficacy of preoperative VRT in reducing postoperative complications in diabetic patients undergoing CABG surgery. Time to “fit for discharge”, incidence of postoperative renal failure, cardiac injury, inflammation, and other health outcomes will be investigated. Methods In this open parallel group randomized controlled trial, 170 diabetic patients undergoing elective or urgent CABG surgery received 1 mL/kg/hour of Hartmann’s solution for 12 consecutive hours prior to surgery, versus routine care. The primary outcome was time until participants were “fit for discharge”, which is defined as presence of: normal temperature, pulse, and respiration; normal oxygen saturation on air; normal bowel function; and physical mobility. Secondary outcomes included: incidence of renal failure; markers of renal function, inflammation, and cardiac damage; operative morbidity; intensive care stay; patient-assessed outcome, including the Coronary Revascularization Outcome Questionnaire; and use of hospital resources. Results Recruitment started in July 2010. Enrolment for the study was completed in July 2014. Data analysis commenced in December 2016. Study results will be submitted for publication in the summer of 2017. Conclusions VRT is a relatively easy treatment to administer in patients undergoing surgical procedures who

  11. The Effects of Preoperative Volume Replacement in Diabetic Patients Undergoing Coronary Artery Bypass Grafting Surgery: Protocol for a Randomized Controlled Trial (VeRDiCT Trial).

    PubMed

    Clout, Madeleine; Harris, Tracy; Rogers, Chris; Culliford, Lucy; Taylor, Jodi; Angelini, Gianni; Narayan, Pradeep; Reeves, Barnaby; Hillier, James; Ashton, Kate; Sarkar, Kunal; Ascione, Raimondo

    2017-06-19

    Diabetes mellitus is a major risk factor for prolonged hospital stays, renal failure, and mortality in patients having coronary artery bypass grafting (CABG). Complications pose a serious threat to patients and prolong intensive care and hospital stays. Low glomerular filtration rate (GFR) due to existing renal impairment or volume depletion may exacerbate acute renal impairment/failure in these patients. Preoperative volume replacement therapy (VRT) is reported to increase the GFR and we hypothesize that VRT will reduce renal impairment and related complications in diabetic patients. The objective of this study is to establish the efficacy of preoperative VRT in reducing postoperative complications in diabetic patients undergoing CABG surgery. Time to "fit for discharge", incidence of postoperative renal failure, cardiac injury, inflammation, and other health outcomes will be investigated. In this open parallel group randomized controlled trial, 170 diabetic patients undergoing elective or urgent CABG surgery received 1 mL/kg/hour of Hartmann's solution for 12 consecutive hours prior to surgery, versus routine care. The primary outcome was time until participants were "fit for discharge", which is defined as presence of: normal temperature, pulse, and respiration; normal oxygen saturation on air; normal bowel function; and physical mobility. Secondary outcomes included: incidence of renal failure; markers of renal function, inflammation, and cardiac damage; operative morbidity; intensive care stay; patient-assessed outcome, including the Coronary Revascularization Outcome Questionnaire; and use of hospital resources. Recruitment started in July 2010. Enrolment for the study was completed in July 2014. Data analysis commenced in December 2016. Study results will be submitted for publication in the summer of 2017. VRT is a relatively easy treatment to administer in patients undergoing surgical procedures who are at risk of renal failure. This experimental protocol

  12. Integra as a Dermal Replacement in a Meshed Composite Skin Graft in a Rat Model: A One-Step Operative Procedure

    DTIC Science & Technology

    2002-01-01

    skin graft (MCSG) using Integra as a dermal template for a meshed split thickness autograft was developed in rats. The silicon layer of Integra was removed, the resulting dermal analogue was meshed (1:1.5), expanded, and placed on excised full thickness wound and covered with a meshed (1:1.5 or 1:6) split thickness autograft. Grafted wounds were dressed with BioBrane, Vaseline gauze, silver-impregnated nylon, or silver-nylon and direct current (SNDC). At scheduled intervals up to 3 months postgrafting, wounds were examined for epithelialization, collagen deposition and

  13. Structure of Lmaj006129AAA, a hypothetical protein from Leishmania major

    SciTech Connect

    Arakaki, Tracy; Le Trong, Isolde; Structural Genomics of Pathogenic Protozoa

    2006-03-01

    The crystal structure of a conserved hypothetical protein from L. major, Pfam sequence family PF04543, structural genomics target ID Lmaj006129AAA, has been determined at a resolution of 1.6 Å. The gene product of structural genomics target Lmaj006129 from Leishmania major codes for a 164-residue protein of unknown function. When SeMet expression of the full-length gene product failed, several truncation variants were created with the aid of Ginzu, a domain-prediction method. 11 truncations were selected for expression, purification and crystallization based upon secondary-structure elements and disorder. The structure of one of these variants, Lmaj006129AAH, was solved by multiple-wavelength anomalous diffraction (MAD)more » using ELVES, an automatic protein crystal structure-determination system. This model was then successfully used as a molecular-replacement probe for the parent full-length target, Lmaj006129AAA. The final structure of Lmaj006129AAA was refined to an R value of 0.185 (R{sub free} = 0.229) at 1.60 Å resolution. Structure and sequence comparisons based on Lmaj006129AAA suggest that proteins belonging to Pfam sequence families PF04543 and PF01878 may share a common ligand-binding motif.« less

  14. AAA-DDD triple hydrogen bond complexes.

    PubMed

    Blight, Barry A; Camara-Campos, Amaya; Djurdjevic, Smilja; Kaller, Martin; Leigh, David A; McMillan, Fiona M; McNab, Hamish; Slawin, Alexandra M Z

    2009-10-07

    Experiment and theory both suggest that the AAA-DDD pattern of hydrogen bond acceptors (A) and donors (D) is the arrangement of three contiguous hydrogen bonding centers that results in the strongest association between two species. Murray and Zimmerman prepared the first example of such a system (complex 3*2) and determined the lower limit of its association constant (K(a)) in CDCl(3) to be 10(5) M(-1) by (1)H NMR spectroscopy (Murray, T. J. and Zimmerman, S. C. J. Am. Chem. Soc. 1992, 114, 4010-4011). The first cationic AAA-DDD pair (3*4(+)) was described by Bell and Anslyn (Bell, D. A. and Anslyn, E. A. Tetrahedron 1995, 51, 7161-7172), with a K(a) > 5 x 10(5) M(-1) in CH(2)Cl(2) as determined by UV-vis spectroscopy. We were recently able to quantify the strength of a neutral AAA-DDD arrangement using a more chemically stable AAA-DDD system, 6*2, which has an association constant of 2 x 10(7) M(-1) in CH(2)Cl(2) (Djurdjevic, S., Leigh, D. A., McNab, H., Parsons, S., Teobaldi, G. and Zerbetto, F. J. Am. Chem. Soc. 2007, 129, 476-477). Here we report on further AA(A) and DDD partners, together with the first precise measurement of the association constant of a cationic AAA-DDD species. Complex 6*10(+)[B(3,5-(CF(3))(2)C(6)H(3))(4)(-)] has a K(a) = 3 x 10(10) M(-1) at RT in CH(2)Cl(2), by far the most strongly bound triple hydrogen bonded system measured to date. The X-ray crystal structure of 6*10(+) with a BPh(4)(-) counteranion shows a planar array of three short (NH...N distances 1.95-2.15 A), parallel (but staggered rather than strictly linear; N-H...N angles 165.4-168.8 degrees), primary hydrogen bonds. These are apparently reinforced, as theory predicts, by close electrostatic interactions (NH-*-N distances 2.78-3.29 A) between each proton and the acceptor atoms of the adjacent primary hydrogen bonds.

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

    PubMed

    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.

  16. The Weekend Effect in AAA Repair.

    PubMed

    O'Donnell, Thomas F X; Li, Chun; Swerdlow, Nicholas J; Liang, Patric; Pothof, Alexander B; Patel, Virendra I; Giles, Kristina A; Malas, Mahmoud B; Schermerhorn, Marc L

    2018-04-18

    Conflicting reports exist regarding whether patients undergoing surgery on the weekend or later in the week experience worse outcomes. We identified patients undergoing abdominal aortic aneurysm (AAA) repair in the Vascular Quality Initiative between 2009 and 2017 [n = 38,498; 30,537 endovascular aneurysm repair (EVAR) and 7961 open repair]. We utilized mixed effects logistic regression to compare adjusted rates of perioperative mortality based on the day of repair. Tuesday was the most common day for elective repair (22%), Friday for symptomatic repairs (20%), and ruptured aneurysms were evenly distributed. Patients with ruptured aneurysms experienced similar adjusted mortality whether they underwent repair during the week or on weekends. Transfers of ruptured AAA were more common over the weekend. However, patients transferred on the weekend experienced higher adjusted mortality than those transferred during the week (28% vs 21%, P = 0.02), despite the fact that during the week, transferred patients actually experienced lower adjusted mortality than patients treated at the index hospital (21% vs 31%, P < 0.01). Among symptomatic patients, adjusted mortality was higher for those undergoing repair over the weekend than those whose surgeries were delayed until a weekday (7.9% vs 3.1%, P = 0.02). Adjusted mortality in elective cases did not vary across the days of the week. Results were consistent between open and EVAR patients. We found no evidence of a weekend effect for ruptured or symptomatic AAA repair. However, patients with ruptured AAA transferred on the weekend experienced higher mortality than those transferred during the week, suggesting a need for improvement in weekend transfer processes.

  17. AAA+ Machines of Protein Destruction in Mycobacteria.

    PubMed

    Alhuwaider, Adnan Ali H; Dougan, David A

    2017-01-01

    The bacterial cytosol is a complex mixture of macromolecules (proteins, DNA, and RNA), which collectively are responsible for an enormous array of cellular tasks. Proteins are central to most, if not all, of these tasks and as such their maintenance (commonly referred to as protein homeostasis or proteostasis) is vital for cell survival during normal and stressful conditions. The two key aspects of protein homeostasis are, (i) the correct folding and assembly of proteins (coupled with their delivery to the correct cellular location) and (ii) the timely removal of unwanted or damaged proteins from the cell, which are performed by molecular chaperones and proteases, respectively. A major class of proteins that contribute to both of these tasks are the AAA+ (ATPases associated with a variety of cellular activities) protein superfamily. Although much is known about the structure of these machines and how they function in the model Gram-negative bacterium Escherichia coli , we are only just beginning to discover the molecular details of these machines and how they function in mycobacteria. Here we review the different AAA+ machines, that contribute to proteostasis in mycobacteria. Primarily we will focus on the recent advances in the structure and function of AAA+ proteases, the substrates they recognize and the cellular pathways they control. Finally, we will discuss the recent developments related to these machines as novel drug targets.

  18. Aortic stent grafting: a new approach to a deadly diagnosis: one hospital's findings in defining new care processes.

    PubMed

    Kalinowski, H

    2001-01-01

    Ruptured abdominal aortic aneurysm (AAA) is the 13th leading cause of death in the United States. Diagnosis is the key to prevention of death from AAA. Millions of Americans harbor this silent, potentially lethal aneurysm. For over 50 years, conventional open surgical repair has been performed for ruptured aortic abdominal aneurysm. It is a major operation with an extended hospital stay and recovery period. An alternative approach to AAA repair has evolved over the past 10 years that combines advances in catheter and stent technologies. With the AAA aortic stent graft, patients usually do not require intensive care and are discharged home within 48 hours of the procedure. This article describes the AAA aortic stent graft procedure, in the formation of a case management team to develop a clinical pathway and standing orders for these patients and defines the outcomes of care.

  19. Coronary artery bypass grafting in a patient with hemophilia B: continuous recombinant factor IX infusion as per the Japanese guidelines for replacement therapy.

    PubMed

    Suzuki, Tomoyuki; Kawamoto, Shunsuke; Kumagai, Kiichiro; Adachi, Osamu; Kanda, Keisuke; Ishikawa, Masaaki; Okitsu, Yoko; Harigae, Hideo; Kurosawa, Shin; Saiki, Yoshikatsu

    2016-08-01

    We herein report our experience of successfully managing the hemostatic system by controlling serum factor IX levels throughout the perioperative period in a patient with hemophilia B. Coronary artery bypass grafting with cardiopulmonary bypass was planned for a 52-year-old man with moderate severity of hemophilia B. During surgery, recombinant factor IX (rFIX; BeneFIX(®) Pfizer Japan inc., Tokyo, Japan) was administered by bolus infusion followed by continuous infusion as per the guidelines of the Japanese Society on Thrombosis and Hemostasis. The operative course was uneventful without any considerable bleeding or complications.

  20. Advanced, Analytic, Automated (AAA) Measurement of Engagement during Learning

    ERIC Educational Resources Information Center

    D'Mello, Sidney; Dieterle, Ed; Duckworth, Angela

    2017-01-01

    It is generally acknowledged that engagement plays a critical role in learning. Unfortunately, the study of engagement has been stymied by a lack of valid and efficient measures. We introduce the advanced, analytic, and automated (AAA) approach to measure engagement at fine-grained temporal resolutions. The AAA measurement approach is grounded in…

  1. NASA Airborne Astronomy Ambassadors (AAA) Professional Development and NASA Connections

    NASA Astrophysics Data System (ADS)

    Backman, D. E.; Clark, C.; Harman, P. K.

    2017-12-01

    NASA's Airborne Astronomy Ambassadors (AAA) program is a three-part professional development (PD) experience for high school physics, astronomy, and earth science teachers. AAA PD consists of: (1) blended learning via webinars, asynchronous content learning, and in-person workshops, (2) a STEM immersion experience at NASA Armstrong's B703 science research aircraft facility in Palmdale, California, and (3) ongoing opportunities for connection with NASA astrophysics and planetary science Subject Matter Experts (SMEs). AAA implementation in 2016-18 involves partnerships between the SETI Institute and seven school districts in northern and southern California. AAAs in the current cohort were selected by the school districts based on criteria developed by AAA program staff working with WestEd evaluation consultants. The selected teachers were then randomly assigned by WestEd to a Group A or B to support controlled testing of student learning. Group A completed their PD during January - August 2017, then participated in NASA SOFIA science flights during fall 2017. Group B will act as a control during the 2017-18 school year, then will complete their professional development and SOFIA flights during 2018. A two-week AAA electromagnetic spectrum and multi-wavelength astronomy curriculum aligned with the Science Framework for California Public Schools and Next Generation Science Standards was developed by program staff for classroom delivery. The curriculum (as well as the AAA's pre-flight PD) capitalizes on NASA content by using "science snapshot" case studies regarding astronomy research conducted by SOFIA. AAAs also interact with NASA SMEs during flight weeks and will translate that interaction into classroom content. The AAA program will make controlled measurements of student gains in standards-based learning plus changes in student attitudes towards STEM, and observe & record the AAAs' implementation of curricular changes. Funded by NASA: NNX16AC51

  2. AAAS Communicating Science Program: Reflections on Evaluation

    NASA Astrophysics Data System (ADS)

    Braha, J.

    2015-12-01

    The AAAS Center for Public Engagement (Center) with science builds capacity for scientists to engage public audiences by fostering collaboration among natural or physical scientists, communication researchers, and public engagement practitioners. The recently launched Leshner Leadership Institute empowers cohorts of mid-career scientists to lead public engagement by supporting their networks of scientists, researchers, and practitioners. The Center works closely with social scientists whose research addresses science communication and public engagement with science to ensure that the Communicating Science training program builds on empirical evidence to inform best practices. Researchers ( Besley, Dudo, & Storkdieck 2015) have helped Center staff and an external evaluator develop pan instrument that measures progress towards goals that are suggested by the researcher, including internal efficacy (increasing scientists' communication skills and confidence in their ability to engage with the public) and external efficacy (scientists' confidence in engagement methods). Evaluation results from one year of the Communicating Science program suggest that the model of training yields positive results that support scientists in the area that should lead to greater engagement. This talk will explore the model for training, which provides a context for strategic communication, as well as the practical factors, such as time, access to public engagement practitioners, and technical skill, that seems to contribute to increased willingness to engage with public audiences. The evaluation program results suggest willingness by training participants to engage directly or to take preliminary steps towards engagement. In the evaluation results, 38% of trained scientists reported time as a barrier to engagement; 35% reported concern that engagement would distract from their work as a barrier. AAAS works to improve practitioner-researcher-scientist networks to overcome such barriers.

  3. Protein quality control in organelles - AAA/FtsH story.

    PubMed

    Janska, Hanna; Kwasniak, Malgorzata; Szczepanowska, Joanna

    2013-02-01

    This review focuses on organellar AAA/FtsH proteases, whose proteolytic and chaperone-like activity is a crucial component of the protein quality control systems of mitochondrial and chloroplast membranes. We compare the AAA/FtsH proteases from yeast, mammals and plants. The nature of the complexes formed by AAA/FtsH proteases and the current view on their involvement in degradation of non-native organellar proteins or assembly of membrane complexes are discussed. Additional functions of AAA proteases not directly connected with protein quality control found in yeast and mammals but not yet in plants are also described shortly. Following an overview of the molecular functions of the AAA/FtsH proteases we discuss physiological consequences of their inactivation in yeast, mammals and plants. The molecular basis of phenotypes associated with inactivation of the AAA/FtsH proteases is not fully understood yet, with the notable exception of those observed in m-AAA protease-deficient yeast cells, which are caused by impaired maturation of mitochondrial ribosomal protein. Finally, examples of cytosolic events affecting protein quality control in mitochondria and chloroplasts are given. This article is part of a Special Issue entitled: Protein Import and Quality Control in Mitochondria and Plastids. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. 42 CFR 137.375 - Are Tribally-owned facilities constructed under section 509 of the Act [25 U.S.C. 458aaa-8...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... section 509 of the Act [25 U.S.C. 458aaa-8] eligible for replacement, maintenance, and improvement funds..., DEPARTMENT OF HEALTH AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Construction Other § 137.375 Are Tribally..., maintenance, and improvement funds on the same basis as if title to such property were vested in the United...

  5. 42 CFR 137.375 - Are Tribally-owned facilities constructed under section 509 of the Act [25 U.S.C. 458aaa-8...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... section 509 of the Act [25 U.S.C. 458aaa-8] eligible for replacement, maintenance, and improvement funds..., DEPARTMENT OF HEALTH AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Construction Other § 137.375 Are Tribally..., maintenance, and improvement funds on the same basis as if title to such property were vested in the United...

  6. 42 CFR 137.375 - Are Tribally-owned facilities constructed under section 509 of the Act [25 U.S.C. 458aaa-8...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... section 509 of the Act [25 U.S.C. 458aaa-8] eligible for replacement, maintenance, and improvement funds..., DEPARTMENT OF HEALTH AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Construction Other § 137.375 Are Tribally..., maintenance, and improvement funds on the same basis as if title to such property were vested in the United...

  7. 42 CFR 137.375 - Are Tribally-owned facilities constructed under section 509 of the Act [25 U.S.C. 458aaa-8...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... section 509 of the Act [25 U.S.C. 458aaa-8] eligible for replacement, maintenance, and improvement funds..., DEPARTMENT OF HEALTH AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Construction Other § 137.375 Are Tribally..., maintenance, and improvement funds on the same basis as if title to such property were vested in the United...

  8. 42 CFR 137.375 - Are Tribally-owned facilities constructed under section 509 of the Act [25 U.S.C. 458aaa-8...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... section 509 of the Act [25 U.S.C. 458aaa-8] eligible for replacement, maintenance, and improvement funds..., DEPARTMENT OF HEALTH AND HUMAN SERVICES TRIBAL SELF-GOVERNANCE Construction Other § 137.375 Are Tribally..., maintenance, and improvement funds on the same basis as if title to such property were vested in the United...

  9. Fundamental Characteristics of AAA+ Protein Family Structure and Function

    PubMed Central

    2016-01-01

    Many complex cellular events depend on multiprotein complexes known as molecular machines to efficiently couple the energy derived from adenosine triphosphate hydrolysis to the generation of mechanical force. Members of the AAA+ ATPase superfamily (ATPases Associated with various cellular Activities) are critical components of many molecular machines. AAA+ proteins are defined by conserved modules that precisely position the active site elements of two adjacent subunits to catalyze ATP hydrolysis. In many cases, AAA+ proteins form a ring structure that translocates a polymeric substrate through the central channel using specialized loops that project into the central channel. We discuss the major features of AAA+ protein structure and function with an emphasis on pivotal aspects elucidated with archaeal proteins. PMID:27703410

  10. Fundamental Characteristics of AAA+ Protein Family Structure and Function.

    PubMed

    Miller, Justin M; Enemark, Eric J

    2016-01-01

    Many complex cellular events depend on multiprotein complexes known as molecular machines to efficiently couple the energy derived from adenosine triphosphate hydrolysis to the generation of mechanical force. Members of the AAA+ ATPase superfamily (ATPases Associated with various cellular Activities) are critical components of many molecular machines. AAA+ proteins are defined by conserved modules that precisely position the active site elements of two adjacent subunits to catalyze ATP hydrolysis. In many cases, AAA+ proteins form a ring structure that translocates a polymeric substrate through the central channel using specialized loops that project into the central channel. We discuss the major features of AAA+ protein structure and function with an emphasis on pivotal aspects elucidated with archaeal proteins.

  11. Advanced, Analytic, Automated (AAA) Measurement of Engagement During Learning.

    PubMed

    D'Mello, Sidney; Dieterle, Ed; Duckworth, Angela

    2017-01-01

    It is generally acknowledged that engagement plays a critical role in learning. Unfortunately, the study of engagement has been stymied by a lack of valid and efficient measures. We introduce the advanced, analytic, and automated (AAA) approach to measure engagement at fine-grained temporal resolutions. The AAA measurement approach is grounded in embodied theories of cognition and affect, which advocate a close coupling between thought and action. It uses machine-learned computational models to automatically infer mental states associated with engagement (e.g., interest, flow) from machine-readable behavioral and physiological signals (e.g., facial expressions, eye tracking, click-stream data) and from aspects of the environmental context. We present15 case studies that illustrate the potential of the AAA approach for measuring engagement in digital learning environments. We discuss strengths and weaknesses of the AAA approach, concluding that it has significant promise to catalyze engagement research.

  12. Advanced, Analytic, Automated (AAA) Measurement of Engagement During Learning

    PubMed Central

    D’Mello, Sidney; Dieterle, Ed; Duckworth, Angela

    2017-01-01

    It is generally acknowledged that engagement plays a critical role in learning. Unfortunately, the study of engagement has been stymied by a lack of valid and efficient measures. We introduce the advanced, analytic, and automated (AAA) approach to measure engagement at fine-grained temporal resolutions. The AAA measurement approach is grounded in embodied theories of cognition and affect, which advocate a close coupling between thought and action. It uses machine-learned computational models to automatically infer mental states associated with engagement (e.g., interest, flow) from machine-readable behavioral and physiological signals (e.g., facial expressions, eye tracking, click-stream data) and from aspects of the environmental context. We present15 case studies that illustrate the potential of the AAA approach for measuring engagement in digital learning environments. We discuss strengths and weaknesses of the AAA approach, concluding that it has significant promise to catalyze engagement research. PMID:29038607

  13. Structural Elements Regulating AAA+ Protein Quality Control Machines.

    PubMed

    Chang, Chiung-Wen; Lee, Sukyeong; Tsai, Francis T F

    2017-01-01

    Members of the ATPases Associated with various cellular Activities (AAA+) superfamily participate in essential and diverse cellular pathways in all kingdoms of life by harnessing the energy of ATP binding and hydrolysis to drive their biological functions. Although most AAA+ proteins share a ring-shaped architecture, AAA+ proteins have evolved distinct structural elements that are fine-tuned to their specific functions. A central question in the field is how ATP binding and hydrolysis are coupled to substrate translocation through the central channel of ring-forming AAA+ proteins. In this mini-review, we will discuss structural elements present in AAA+ proteins involved in protein quality control, drawing similarities to their known role in substrate interaction by AAA+ proteins involved in DNA translocation. Elements to be discussed include the pore loop-1, the Inter-Subunit Signaling (ISS) motif, and the Pre-Sensor I insert (PS-I) motif. Lastly, we will summarize our current understanding on the inter-relationship of those structural elements and propose a model how ATP binding and hydrolysis might be coupled to polypeptide translocation in protein quality control machines.

  14. Bone grafts.

    PubMed

    Hubble, Matthew J W

    2002-09-01

    Bone grafts are used in musculoskeletal surgery to restore structural integrity and enhance osteogenic potential. The demand for bone graft for skeletal reconstruction in bone tumor, revision arthroplasty, and trauma surgery, couple with recent advances in understanding and application of the biology of bone transplantation, has resulted in an exponential increase in the number of bone-grafting procedures performed over the last decade. It is estimated that 1.5 million bone-grafting procedures are currently performed worldwide each year, compared to a fraction of that number 20 years ago. Major developments also have resulted in the harvesting, storage, and use of bone grafts and production of graft derivatives, substitutes, and bone-inducing agents.

  15. Investigating the effect of remote ischaemic preconditioning on biomarkers of stress and injury-related signalling in patients having isolated coronary artery bypass grafting or aortic valve replacement using cardiopulmonary bypass: study protocol for a randomized controlled trial.

    PubMed

    Fiorentino, Francesca; Angelini, Gianni D; Suleiman, M-Saadeh; Rahman, Alima; Anderson, Jon; Bryan, Alan J; Culliford, Lucy A; Moscarelli, Marco; Punjabi, Prakash P; Reeves, Barnaby C

    2015-04-23

    Ischaemia-reperfusion injury occurs during heart surgery that uses cardiopulmonary bypass (CPB) and cardioplegic arrest. It is hypothesised that remote ischaemic preconditioning (RIPC) protects the heart against such injury. Despite the numerous studies investigating the protective effects of RIPC, there is still uncertainty about the interpretation of the findings as well as conflicting results between studies. The objective of this trial is to investigate the cardioprotective effect of RIPC in patients having coronary artery bypass grafting (CABG) or aortic valve replacement surgery. This will be achieved by estimating the effect of the intervention in the two groups of pathologies and by investigating the signalling mechanisms that may underpin the cardioprotective effect. A two-centre randomised controlled trial will be used to investigate the effects of RIPC in two pathologies: patients having isolated CABG and those having aortic valve replacement surgery (AVR) with CPB. Participants will be randomised to RIPC or control (sham RIPC), stratified by surgical stratum. The intervention will be delivered by a research nurse. Data will be collected by a research nurse blinded to the intervention. The patient and the theatre staff are also blinded to the allocation. Markers of myocardial injury and inflammation will be measured in myocardial biopsies and in blood samples at different times. This trial is designed to investigate whether RIPC will reduce myocardial injury and inflammation following heart surgery and whether there is a difference in effect between participants having CABG or AVR. This trial is a unique opportunity to study the mechanisms associated with RIPC using human myocardial tissue and blood, and to relate these to the extent of myocardial injury/protection. Current Controlled Trials ISRCTN33084113 (25 March 2013).

  16. Reinterventions after open and endovascular AAA repair.

    PubMed

    Malina, M

    2015-04-01

    Reinterventions seem to occur more frequently after endovascular aneurysm repair than after open surgical repair and are encountered in about 20% versus 10% of the cases, respectively. However, reinterventions following endovascular repair are predominantly endoluminal and early reinterventions are more frequent after open repair. The indications for reintervention after EVAR have changed over time. The incidence and type of reintervention depends on the complexity of the primary procedure, irrespective of whether it was open or endovascular. The use of a device outside instructions for use is associated with a higher complication rate but it may nevertheless be fully justified. Advanced stent-grafts such as fenestrated and branched devices require secondary procedures more often than a standard stent-graft. Similarly, more complex open repair, e.g. a bifurcated bypass, reimplantation of visceral arteries or a redo procedure, is also associated with more reinterventions than a simple tube graft. This manuscript presents some of the most common complications of open and endovascular aortic aneurysm repair and the reinterventions they require. Many of the complications are similar with both open and endovascular techniques. Limb thrombosis, infections and endoleaks are the most frequent indications for reintervention.

  17. The Diverse AAA+ Machines that Repair Inhibited Rubisco Active Sites

    PubMed Central

    Mueller-Cajar, Oliver

    2017-01-01

    Gaseous carbon dioxide enters the biosphere almost exclusively via the active site of the enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). This highly conserved catalyst has an almost universal propensity to non-productively interact with its substrate ribulose 1,5-bisphosphate, leading to the formation of dead-end inhibited complexes. In diverse autotrophic organisms this tendency has been counteracted by the recruitment of dedicated AAA+ (ATPases associated with various cellular activities) proteins that all use the energy of ATP hydrolysis to remodel inhibited Rubisco active sites leading to release of the inhibitor. Three evolutionarily distinct classes of these Rubisco activases (Rcas) have been discovered so far. Green and red-type Rca are mostly found in photosynthetic eukaryotes of the green and red plastid lineage respectively, whereas CbbQO is associated with chemoautotrophic bacteria. Ongoing mechanistic studies are elucidating how the various motors are utilizing both similar and contrasting strategies to ultimately perform their common function of cracking the inhibited Rubisco active site. The best studied mechanism utilized by red-type Rca appears to involve transient threading of the Rubisco large subunit C-terminal peptide, reminiscent of the action performed by Clp proteases. As well as providing a fascinating example of convergent molecular evolution, Rca proteins can be considered promising crop-improvement targets. Approaches aiming to replace Rubisco in plants with improved enzymes will need to ensure the presence of a compatible Rca protein. The thermolability of the Rca protein found in crop plants provides an opportunity to fortify photosynthesis against high temperature stress. Photosynthesis also appears to be limited by Rca when light conditions are fluctuating. Synthetic biology strategies aiming to enhance the autotrophic CO2 fixation machinery will need to take into consideration the requirement for Rubisco activases

  18. Assessing heterogeneity in oligomeric AAA+ machines.

    PubMed

    Sysoeva, Tatyana A

    2017-03-01

    ATPases Associated with various cellular Activities (AAA+ ATPases) are molecular motors that use the energy of ATP binding and hydrolysis to remodel their target macromolecules. The majority of these ATPases form ring-shaped hexamers in which the active sites are located at the interfaces between neighboring subunits. Structural changes initiate in an active site and propagate to distant motor parts that interface and reshape the target macromolecules, thereby performing mechanical work. During the functioning cycle, the AAA+ motor transits through multiple distinct states. Ring architecture and placement of the catalytic sites at the intersubunit interfaces allow for a unique level of coordination among subunits of the motor. This in turn results in conformational differences among subunits and overall asymmetry of the motor ring as it functions. To date, a large amount of structural information has been gathered for different AAA+ motors, but even for the most characterized of them only a few structural states are known and the full mechanistic cycle cannot be yet reconstructed. Therefore, the first part of this work will provide a broad overview of what arrangements of AAA+ subunits have been structurally observed focusing on diversity of ATPase oligomeric ensembles and heterogeneity within the ensembles. The second part of this review will concentrate on methods that assess structural and functional heterogeneity among subunits of AAA+ motors, thus bringing us closer to understanding the mechanism of these fascinating molecular motors.

  19. AAA (2010) CAPD clinical practice guidelines: need for an update.

    PubMed

    DeBonis, David A

    2017-09-01

    Review and critique of the clinical value of the AAA CAPD guidance document in light of criteria for credible and useful guidance documents, as discussed by Field and Lohr. A qualitative review of the of the AAA CAPD guidelines using a framework by Field and Lohr to assess their relative value in supporting the assessment and management of CAPD referrals. Relevant literature available through electronic search tools and published texts were used along with the AAA CAPD guidance document and the chapter by Field and Lohr. The AAA document does not meet many of the key requirements discussed by Field and Lohr. It does not reflect the current literature, fails to help clinicians understand for whom auditory processing testing and intervention would be most useful, includes contradictory suggestions which reduce clarity and appears to avoid conclusions that might cast the CAPD construct in a negative light. It also does not include input from diverse affected groups. All of these reduce the document's credibility. The AAA CAPD guidance document will need to be updated and re-conceptualised in order to provide meaningful guidance for clinicians.

  20. Role of AAA(+)-proteins in peroxisome biogenesis and function.

    PubMed

    Grimm, Immanuel; Erdmann, Ralf; Girzalsky, Wolfgang

    2016-05-01

    Mutations in the PEX1 gene, which encodes a protein required for peroxisome biogenesis, are the most common cause of the Zellweger spectrum diseases. The recognition that Pex1p shares a conserved ATP-binding domain with p97 and NSF led to the discovery of the extended family of AAA+-type ATPases. So far, four AAA+-type ATPases are related to peroxisome function. Pex6p functions together with Pex1p in peroxisome biogenesis, ATAD1/Msp1p plays a role in membrane protein targeting and a member of the Lon-family of proteases is associated with peroxisomal quality control. This review summarizes the current knowledge on the AAA+-proteins involved in peroxisome biogenesis and function.

  1. m-AAA proteases, mitochondrial calcium homeostasis and neurodegeneration

    PubMed Central

    Patron, Maria; Sprenger, Hans-Georg; Langer, Thomas

    2018-01-01

    The function of mitochondria depends on ubiquitously expressed and evolutionary conserved m-AAA proteases in the inner membrane. These ATP-dependent peptidases form hexameric complexes built up of homologous subunits. AFG3L2 subunits assemble either into homo-oligomeric isoenzymes or with SPG7 (paraplegin) subunits into hetero-oligomeric proteolytic complexes. Mutations in AFG3L2 are associated with dominant spinocerebellar ataxia (SCA28) characterized by the loss of Purkinje cells, whereas mutations in SPG7 cause a recessive form of hereditary spastic paraplegia (HSP7) with motor neurons of the cortico-spinal tract being predominantly affected. Pleiotropic functions have been assigned to m-AAA proteases, which act as quality control and regulatory enzymes in mitochondria. Loss of m-AAA proteases affects mitochondrial protein synthesis and respiration and leads to mitochondrial fragmentation and deficiencies in the axonal transport of mitochondria. Moreover m-AAA proteases regulate the assembly of the mitochondrial calcium uniporter (MCU) complex. Impaired degradation of the MCU subunit EMRE in AFG3L2-deficient mitochondria results in the formation of deregulated MCU complexes, increased mitochondrial calcium uptake and increased vulnerability of neurons for calcium-induced cell death. A reduction of calcium influx into the cytosol of Purkinje cells rescues ataxia in an AFG3L2-deficient mouse model. In this review, we discuss the relationship between the m-AAA protease and mitochondrial calcium homeostasis and its relevance for neurodegeneration and describe a novel mouse model lacking MCU specifically in Purkinje cells. Our results pledge for a novel view on m-AAA proteases that integrates their pleiotropic functions in mitochondria to explain the pathogenesis of associated neurodegenerative disorders. PMID:29451229

  2. Meiotic Clade AAA ATPases: Protein Polymer Disassembly Machines.

    PubMed

    Monroe, Nicole; Hill, Christopher P

    2016-05-08

    Meiotic clade AAA ATPases (ATPases associated with diverse cellular activities), which were initially grouped on the basis of phylogenetic classification of their AAA ATPase cassette, include four relatively well characterized family members, Vps4, spastin, katanin and fidgetin. These enzymes all function to disassemble specific polymeric protein structures, with Vps4 disassembling the ESCRT-III polymers that are central to the many membrane-remodeling activities of the ESCRT (endosomal sorting complexes required for transport) pathway and spastin, katanin p60 and fidgetin affecting multiple aspects of cellular dynamics by severing microtubules. They share a common domain architecture that features an N-terminal MIT (microtubule interacting and trafficking) domain followed by a single AAA ATPase cassette. Meiotic clade AAA ATPases function as hexamers that can cycle between the active assembly and inactive monomers/dimers in a regulated process, and they appear to disassemble their polymeric substrates by translocating subunits through the central pore of their hexameric ring. Recent studies with Vps4 have shown that nucleotide-induced asymmetry is a requirement for substrate binding to the pore loops and that recruitment to the protein lattice via MIT domains also relieves autoinhibition and primes the AAA ATPase cassettes for substrate binding. The most striking, unifying feature of meiotic clade AAA ATPases may be their MIT domain, which is a module that is found in a wide variety of proteins that localize to ESCRT-III polymers. Spastin also displays an adjacent microtubule binding sequence, and the presence of both ESCRT-III and microtubule binding elements may underlie the recent findings that the ESCRT-III disassembly function of Vps4 and the microtubule-severing function of spastin, as well as potentially katanin and fidgetin, are highly coordinated. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. m-AAA proteases, mitochondrial calcium homeostasis and neurodegeneration.

    PubMed

    Patron, Maria; Sprenger, Hans-Georg; Langer, Thomas

    2018-03-01

    The function of mitochondria depends on ubiquitously expressed and evolutionary conserved m-AAA proteases in the inner membrane. These ATP-dependent peptidases form hexameric complexes built up of homologous subunits. AFG3L2 subunits assemble either into homo-oligomeric isoenzymes or with SPG7 (paraplegin) subunits into hetero-oligomeric proteolytic complexes. Mutations in AFG3L2 are associated with dominant spinocerebellar ataxia (SCA28) characterized by the loss of Purkinje cells, whereas mutations in SPG7 cause a recessive form of hereditary spastic paraplegia (HSP7) with motor neurons of the cortico-spinal tract being predominantly affected. Pleiotropic functions have been assigned to m-AAA proteases, which act as quality control and regulatory enzymes in mitochondria. Loss of m-AAA proteases affects mitochondrial protein synthesis and respiration and leads to mitochondrial fragmentation and deficiencies in the axonal transport of mitochondria. Moreover m-AAA proteases regulate the assembly of the mitochondrial calcium uniporter (MCU) complex. Impaired degradation of the MCU subunit EMRE in AFG3L2-deficient mitochondria results in the formation of deregulated MCU complexes, increased mitochondrial calcium uptake and increased vulnerability of neurons for calcium-induced cell death. A reduction of calcium influx into the cytosol of Purkinje cells rescues ataxia in an AFG3L2-deficient mouse model. In this review, we discuss the relationship between the m-AAA protease and mitochondrial calcium homeostasis and its relevance for neurodegeneration and describe a novel mouse model lacking MCU specifically in Purkinje cells. Our results pledge for a novel view on m-AAA proteases that integrates their pleiotropic functions in mitochondria to explain the pathogenesis of associated neurodegenerative disorders.

  4. Readily functionalized AAA-DDD triply hydrogen-bonded motifs.

    PubMed

    Tong, Feng; Linares-Mendez, Iamnica J; Han, Yi-Fei; Wisner, James A; Wang, Hong-Bo

    2018-04-25

    Herein we present a new, readily functionalized AAA-DDD hydrogen bond array. A novel AAA monomeric unit (3a-b) was obtained from a two-step synthetic procedure starting with 2-aminonicotinaldehyde via microwave radiation (overall yield of 52-66%). 1H NMR and fluorescence spectroscopy confirmed the complexation event with a calculated association constant of 1.57 × 107 M-1. Likewise, the usefulness of this triple hydrogen bond motif in supramolecular polymerization was demonstrated through viscosity measurements in a crosslinked supramolecular alternating copolymer.

  5. Functional Diversity of AAA+ Protease Complexes in Bacillus subtilis

    PubMed Central

    Elsholz, Alexander K. W.; Birk, Marlene S.; Charpentier, Emmanuelle; Turgay, Kürşad

    2017-01-01

    Here, we review the diverse roles and functions of AAA+ protease complexes in protein homeostasis, control of stress response and cellular development pathways by regulatory and general proteolysis in the Gram-positive model organism Bacillus subtilis. We discuss in detail the intricate involvement of AAA+ protein complexes in controlling sporulation, the heat shock response and the role of adaptor proteins in these processes. The investigation of these protein complexes and their adaptor proteins has revealed their relevance for Gram-positive pathogens and their potential as targets for new antibiotics. PMID:28748186

  6. The Airborne Astronomy Ambassadors (AAA) Program and NASA Astrophysics Connections

    NASA Astrophysics Data System (ADS)

    Backman, Dana Edward; Clark, Coral; Harman, Pamela

    2018-01-01

    The NASA Airborne Astronomy Ambassadors (AAA) program is a three-part professional development (PD) experience for high school physics, astronomy, and earth science teachers. AAA PD consists of: (1) blended learning via webinars, asynchronous content delivery, and in-person workshops, (2) a STEM immersion experience at NASA Armstrong’s B703 science research aircraft facility in Palmdale, California, including interactions with NASA astrophysics & planetary science Subject Matter Experts (SMEs) during science flights on SOFIA, and (3) continuing post-flight opportunities for teacher & student connections with SMEs.

  7. Functional Diversity of AAA+ Protease Complexes in Bacillus subtilis.

    PubMed

    Elsholz, Alexander K W; Birk, Marlene S; Charpentier, Emmanuelle; Turgay, Kürşad

    2017-01-01

    Here, we review the diverse roles and functions of AAA+ protease complexes in protein homeostasis, control of stress response and cellular development pathways by regulatory and general proteolysis in the Gram-positive model organism Bacillus subtilis . We discuss in detail the intricate involvement of AAA+ protein complexes in controlling sporulation, the heat shock response and the role of adaptor proteins in these processes. The investigation of these protein complexes and their adaptor proteins has revealed their relevance for Gram-positive pathogens and their potential as targets for new antibiotics.

  8. Bone graft

    MedlinePlus

    ... dry. Follow instructions about showering. DO NOT smoke. Smoking slows or prevents bone healing. If you smoke, the graft is more likely to fail. Be aware that nicotine patches slow healing just like smoking does.

  9. Molecularly Defined Nanostructures Based on a Novel AAA-DDD Triple Hydrogen-Bonding Motif.

    PubMed

    Papmeyer, Marcus; Vuilleumier, Clément A; Pavan, Giovanni M; Zhurov, Konstantin O; Severin, Kay

    2016-01-26

    A facile and flexible method for the synthesis of a new AAA-DDD triple hydrogen-bonding motif is described. Polytopic supramolecular building blocks with precisely oriented AAA and DDD groups are thus accessible in few steps. These building blocks were used for the assembly of large macrocycles featuring four AAA-DDD interactions and a macrobicyclic complex with a total of six AAA-DDD interactions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. The Adult Asperger Assessment (AAA): A Diagnostic Method

    ERIC Educational Resources Information Center

    Baron-Cohen, Simon; Wheelwright, Sally; Robinson, Janine; Woodbury-Smith, Marc

    2005-01-01

    At the present time there are a large number of adults who have "suspected" Asperger syndrome (AS). In this paper we describe a new instrument, the Adult Asperger Assessment (AAA), developed in our clinic for adults with AS. The need for a new instrument relevant to the diagnosis of AS in adulthood arises because existing instruments are designed…

  11. 26 CFR 1.1368-2 - Accumulated adjustments account (AAA).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... TAX (CONTINUED) INCOME TAXES (CONTINUED) Small Business Corporations and Their Shareholders § 1.1368-2... earnings and profits or previously taxed income pursuant to an election made under section 1368(e)(3) and... AAA for redemptions and distributions in the year of a redemption. (c) Distribution of money and loss...

  12. 26 CFR 1.1368-2 - Accumulated adjustments account (AAA).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... TAX (CONTINUED) INCOME TAXES (CONTINUED) Small Business Corporations and Their Shareholders § 1.1368-2... earnings and profits or previously taxed income pursuant to an election made under section 1368(e)(3) and... AAA for redemptions and distributions in the year of a redemption. (c) Distribution of money and loss...

  13. 26 CFR 1.1368-2 - Accumulated adjustments account (AAA).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... TAX (CONTINUED) INCOME TAXES (CONTINUED) Small Business Corporations and Their Shareholders § 1.1368-2... earnings and profits or previously taxed income pursuant to an election made under section 1368(e)(3) and... AAA for redemptions and distributions in the year of a redemption. (c) Distribution of money and loss...

  14. 26 CFR 1.1368-2 - Accumulated adjustments account (AAA).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... TAX (CONTINUED) INCOME TAXES Small Business Corporations and Their Shareholders § 1.1368-2 Accumulated... earnings and profits or previously taxed income pursuant to an election made under section 1368(e)(3) and... AAA for redemptions and distributions in the year of a redemption. (c) Distribution of money and loss...

  15. 26 CFR 1.1368-2 - Accumulated adjustments account (AAA).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... TAX (CONTINUED) INCOME TAXES (CONTINUED) Small Business Corporations and Their Shareholders § 1.1368-2... earnings and profits or previously taxed income pursuant to an election made under section 1368(e)(3) and... AAA for redemptions and distributions in the year of a redemption. (c) Distribution of money and loss...

  16. AAAS: Automated Affirmative Action System. General Description, Phase 1.

    ERIC Educational Resources Information Center

    Institute for Services to Education, Inc., Washington, DC. TACTICS Management Information Systems Directorate.

    This document describes phase 1 of the Automated Affirmative Action System (AAAS) of the Tuskegee Institute, which was designed to organize an inventory of any patterns of job classification and assignment identifiable by sex or minority group; any job classification or organizational unit where women and minorities are not employed or are…

  17. Inhibition of early AAA formation by aortic intraluminal pentagalloyl glucose (PGG) infusion in a novel porcine AAA model.

    PubMed

    Kloster, Brian O; Lund, Lars; Lindholt, Jes S

    2016-05-01

    The vast majority of abdominal aortic aneurysms found in screening programs are small, and as no effective treatment exits, many will expand until surgery is indicated. Therefore, it remains intriguing to develop a safe and low cost treatment of these small aneurysms, that is able to prevent or delay their expansion. In this study, we investigated whether intraluminal delivered pentagalloyl glucose (PGG) can impair the early AAA development in a porcine model. The infrarenal aorta was exposed in thirty pigs. Twenty underwent an elastase based AAA inducing procedure and ten of these received an additional intraluminal PGG infusion. The final 10 were sham operated and served as controls. All pigs who only had an elastase infusion developed macroscopically expanding AAAs. In pigs treated with an additional PGG infusion the growth rate of the AP-diameter rapidly returned to physiological values as seen in the control group. In the elastase group, histology revealed more or less complete resolution of the elastic lamellae in the media while they were more abundant, coherent and structurally organized in the PGG group. The control group displayed normal physiological growth and histology. In our model, intraluminal delivered PGG is able to penetrate the aortic wall from the inside and impair the early AAA development by stabilizing the elastic lamellae and preserving their integrity. The principle holds a high clinical potential if it can be translated to human conditions, since it, if so, potentially could represent a new drug for stabilizing small abdominal aneurysms.

  18. Prevention of Kinked Stent Graft Limb Due to Severe Angulated Proximal Neck during Endovascular Repair for Abdominal Aortic Aneurysm.

    PubMed

    Oh, Pyung Chun; Kim, Minsu; Shin, Eak Kyun; Kang, Woong Chol

    2018-04-20

    Although the technology of endovascular aortic repair (EVAR) for abdominal aortic aneurysm (AAA) is evolving that make it appealing for challenging anatomy, proximal aortic neck morphology, especially severe angulation, is still one of the most determinants for a successful procedure. We describe a patient of AAA with severely angulated proximal neck, in whom kinked stent graft limb occurred against severe angulation of proximal neck. Then, we suggested how to prevent this complication in the second patient. Our case demonstrated the stent graft limb could be kinked by severe aortic neck angulation, making it challenging. However, the kinked stent graft limb could be prevented by deploying stent graft limbs below the most severely angulated aortic neck intentionally.

  19. A structural analysis of the AAA+ domains in Saccharomyces cerevisiae cytoplasmic dynein

    PubMed Central

    Gleave, Emma S.; Schmidt, Helgo; Carter, Andrew P.

    2014-01-01

    Dyneins are large protein complexes that act as microtubule based molecular motors. The dynein heavy chain contains a motor domain which is a member of the AAA+ protein family (ATPases Associated with diverse cellular Activities). Proteins of the AAA+ family show a diverse range of functionalities, but share a related core AAA+ domain, which often assembles into hexameric rings. Dynein is unusual because it has all six AAA+ domains linked together, in one long polypeptide. The dynein motor domain generates movement by coupling ATP driven conformational changes in the AAA+ ring to the swing of a motile element called the linker. Dynein binds to its microtubule track via a long antiparallel coiled-coil stalk that emanates from the AAA+ ring. Recently the first high resolution structures of the dynein motor domain were published. Here we provide a detailed structural analysis of the six AAA+ domains using our Saccharomycescerevisiae crystal structure. We describe how structural similarities in the dynein AAA+ domains suggest they share a common evolutionary origin. We analyse how the different AAA+ domains have diverged from each other. We discuss how this is related to the function of dynein as a motor protein and how the AAA+ domains of dynein compare to those of other AAA+ proteins. PMID:24680784

  20. A structural analysis of the AAA+ domains in Saccharomyces cerevisiae cytoplasmic dynein.

    PubMed

    Gleave, Emma S; Schmidt, Helgo; Carter, Andrew P

    2014-06-01

    Dyneins are large protein complexes that act as microtubule based molecular motors. The dynein heavy chain contains a motor domain which is a member of the AAA+ protein family (ATPases Associated with diverse cellular Activities). Proteins of the AAA+ family show a diverse range of functionalities, but share a related core AAA+ domain, which often assembles into hexameric rings. Dynein is unusual because it has all six AAA+ domains linked together, in one long polypeptide. The dynein motor domain generates movement by coupling ATP driven conformational changes in the AAA+ ring to the swing of a motile element called the linker. Dynein binds to its microtubule track via a long antiparallel coiled-coil stalk that emanates from the AAA+ ring. Recently the first high resolution structures of the dynein motor domain were published. Here we provide a detailed structural analysis of the six AAA+ domains using our Saccharomycescerevisiae crystal structure. We describe how structural similarities in the dynein AAA+ domains suggest they share a common evolutionary origin. We analyse how the different AAA+ domains have diverged from each other. We discuss how this is related to the function of dynein as a motor protein and how the AAA+ domains of dynein compare to those of other AAA+ proteins. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Impact of graft composition on the systemic inflammatory response after an elective repair of an abdominal aortic aneurysm

    PubMed Central

    Baek, Jong Kwan; Kwon, Hyunwook; Ko, Gi-Young; Kim, Min Joo; Han, Youngjin; Chung, Young Soo; Park, Hojong; Kwon, Tae-Won

    2015-01-01

    Purpose The present study aimed to evaluate the risk factors and the role of graft material in the development of an acute phase systemic inflammatory response, and the clinical outcome in patients who undergo endovascular aneurysm repair (EVAR) or open surgical repair (OSR) of an abdominal aortic aneurysm (AAA). Methods We retrospectively evaluated the risk factors and the role of graft material in an increased risk of developing systemic inflammatory response syndrome (SIRS), and the clinical outcome in patients who underwent EVAR or OSR of an AAA. Results A total of 308 consecutive patients who underwent AAA repair were included; 178 received EVAR and 130 received OSR. There was no significant difference in the incidence of SIRS between EVAR patients and OSR patients. Regardless of treatment modality, SIRS was observed more frequently in patients treated with woven polyester grafts. Postoperative hospitalization was significantly prolonged in patients that experienced SIRS. In multivariate analyses, the initial white blood cell count (P = 0.001) and the use of woven polyester grafts (P = 0.005) were significantly associated with an increased risk of developing SIRS in patients who underwent EVAR. By contrast, the use of woven polyester grafts was the only factor associated with an increased risk of developing SIRS in patients who underwent OSR, although this was not statistically significant (P = 0.052). Conclusion The current study shows that the graft composition plays a primordial role in the development of SIRS, and it leads to prolonged hospitalization in both EVAR and OSR patients. PMID:25553321

  2. Morphological Differences in the Aorto-iliac Segment in AAA Patients of Caucasian and Asian Origin.

    PubMed

    Banzic, I; Lu, Q; Zhang, L; Stepak, H; Davidovic, L; Oszkinis, G; Mladenovic, A; Markovic, M; Rancic, Z; Jing, Z; Brankovic, M

    2016-06-01

    The objective was to quantify aorto-iliac morphology differences between AAA patients of Caucasian and Asian origin. Additionally, the impact of patient demographic characteristics was assessed, which could influence the morphological differences. This international multicentre study included two tertiary referral institutions from Europe and one from China. CT scans with 3D reconstruction of 296 patients with infrarenal AAA >5 cm were analysed. Eighteen measurements were recorded from each CT scan and compared between Caucasian and Asian patients. Caucasian patients had longer common iliac arteries (right: 65.0 vs. 33.1 mm, p < .001 left: 65.0 vs. 35.2 mm, p < .001), longer aneurysm neck (33.0 vs. 28.4 mm, p < .001), greater aneurysm to aortic axis angle (153.0° vs. 142.2°, p < .001), and longer combined aorto-iliac length (195.7 vs. 189.2 mm, p < .001). However, Asian patients had a longer infrarenal abdominal aorta (152.0 vs. 130.0 mm, p < .001), longer AAA (126.2 vs. 93.0 mm), and greater linear distance from renal artery to aorto-iliac bifurcation (143.6 vs. 116.0 mm, p < .001). Caucasian patients had a larger inner common iliac artery diameter (right: 16.0 vs. 14.9 mm, p < .001, left: 16.0 vs. 15.2 mm, p < .001), larger inner exernal iliac artery diameter (right: 9.0 vs. 7.5 mm, p < .001 left: 9.0 vs. 7.7 mm, p < .001), and larger inner common femoral artery diameter (right: 10.0 vs. 5.9 mm, p < .001 left: 10.0 vs. 6.1 mm, p < .001). No difference was observed in AAA transverse diameter (62.0 vs. 63.1 mm, p = .492). The results showed that aorto-iliac anatomy in Caucasians differs significantly from Asians, particularly in the length of the common iliac arteries and infrarenal abdominal aorta, and in the transverse diameter of the common, external iliac, and common femoral arteries. Therefore, the exact criteria for stent graft design are dependent on the racial origin of the patient. Copyright © 2015 European

  3. Rubisco Activases: AAA+ Chaperones Adapted to Enzyme Repair.

    PubMed

    Bhat, Javaid Y; Thieulin-Pardo, Gabriel; Hartl, F Ulrich; Hayer-Hartl, Manajit

    2017-01-01

    Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), the key enzyme of the Calvin-Benson-Bassham cycle of photosynthesis, requires conformational repair by Rubisco activase for efficient function. Rubisco mediates the fixation of atmospheric CO 2 by catalyzing the carboxylation of the five-carbon sugar ribulose-1,5-bisphosphate (RuBP). It is a remarkably inefficient enzyme, and efforts to increase crop yields by bioengineering Rubisco remain unsuccessful. This is due in part to the complex cellular machinery required for Rubisco biogenesis and metabolic maintenance. To function, Rubisco must undergo an activation process that involves carboxylation of an active site lysine by a non-substrate CO 2 molecule and binding of a Mg 2+ ion. Premature binding of the substrate RuBP results in an inactive enzyme. Moreover, Rubisco can also be inhibited by a range of sugar phosphates, some of which are "misfire" products of its multistep catalytic reaction. The release of the inhibitory sugar molecule is mediated by the AAA+ protein Rubisco activase (Rca), which couples hydrolysis of ATP to the structural remodeling of Rubisco. Rca enzymes are found in the vast majority of photosynthetic organisms, from bacteria to higher plants. They share a canonical AAA+ domain architecture and form six-membered ring complexes but are diverse in sequence and mechanism, suggesting their convergent evolution. In this review, we discuss recent advances in understanding the structure and function of this important group of client-specific AAA+ proteins.

  4. Rubisco Activases: AAA+ Chaperones Adapted to Enzyme Repair

    PubMed Central

    Bhat, Javaid Y.; Thieulin-Pardo, Gabriel; Hartl, F. Ulrich; Hayer-Hartl, Manajit

    2017-01-01

    Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), the key enzyme of the Calvin-Benson-Bassham cycle of photosynthesis, requires conformational repair by Rubisco activase for efficient function. Rubisco mediates the fixation of atmospheric CO2 by catalyzing the carboxylation of the five-carbon sugar ribulose-1,5-bisphosphate (RuBP). It is a remarkably inefficient enzyme, and efforts to increase crop yields by bioengineering Rubisco remain unsuccessful. This is due in part to the complex cellular machinery required for Rubisco biogenesis and metabolic maintenance. To function, Rubisco must undergo an activation process that involves carboxylation of an active site lysine by a non-substrate CO2 molecule and binding of a Mg2+ ion. Premature binding of the substrate RuBP results in an inactive enzyme. Moreover, Rubisco can also be inhibited by a range of sugar phosphates, some of which are “misfire” products of its multistep catalytic reaction. The release of the inhibitory sugar molecule is mediated by the AAA+ protein Rubisco activase (Rca), which couples hydrolysis of ATP to the structural remodeling of Rubisco. Rca enzymes are found in the vast majority of photosynthetic organisms, from bacteria to higher plants. They share a canonical AAA+ domain architecture and form six-membered ring complexes but are diverse in sequence and mechanism, suggesting their convergent evolution. In this review, we discuss recent advances in understanding the structure and function of this important group of client-specific AAA+ proteins. PMID:28443288

  5. Proximal Tibial Bone Graft

    MedlinePlus

    ... All Site Content AOFAS / FootCareMD / Treatments Proximal Tibial Bone Graft Page Content What is a bone graft? Bone grafts may be needed for various ... the proximal tibia. What is a proximal tibial bone graft? Proximal tibial bone graft (PTBG) is a ...

  6. Management of an infected aortic graft with endovascular stent grafting.

    PubMed

    Jamel, Sara; Attia, Rizwan; Young, Christopher

    2013-01-01

    Aortic graft infection, one of the most common fatal complications of aortovascular surgery, is managed mainly by the removal of infected graft material and re-establishment of vascular continuity using an extra-anatomical bypass or in situ graft replacement. Despite significant progress in perioperative, surgical, and medical treatments, the mortality and morbidity for this condition remain high. Here, we report the use of endograft implantation and prolonged intravenous antibiotics to successfully treat a life-threatening Dacron aortic tube graft infection and anastomotic leak. Although the gold standard is surgical removal of infected material and repair with a homograft, in certain extremely high-risk patients such as ours, an alternate strategy may be warranted when the risks associated with surgery are prohibitive. Endovascular repair of a surgical Dacron graft leak may provide a novel temporizing measure in the acute setting, allowing for delayed semi-urgent surgical intervention, or it may provide a definitive treatment, as in our case. At the four-year follow-up, our patient was well with a good quality of life and with no clinical, radiological, or biochemical evidence of infection.

  7. Multiple organ embolization with vegetation on an elephant trunk graft.

    PubMed

    Tashiro, Miwa; Yamamoto, Masaki; Nishimori, Hideaki; Fukutomi, Takashi; Handa, Takemi; Kondo, Nobuo; Orihashi, Kazumasa

    2017-01-01

    We encountered a rare case of infection in a vascular graft created using the elephant trunk technique. A 65-year-old woman who underwent total arch replacement with the elephant trunk technique was re-admitted with fever. She developed embolization of multiple organs from vegetation attached to the elephant trunk graft which was elucidated by transesophageal echocardiography. Surgery for ruptured jejunal artery aneurysm was performed, and the graft infection healed after long-term antibiotic therapy with the prosthesis left in situ. Graft infection may generate vegetations on an elephant trunk graft. Transesophageal echocardiography is a helpful tool for accurate diagnosis.

  8. Bone Graft Alternatives

    MedlinePlus

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

  9. Structure and evolution of N-domains in AAA metalloproteases.

    PubMed

    Scharfenberg, Franka; Serek-Heuberger, Justyna; Coles, Murray; Hartmann, Marcus D; Habeck, Michael; Martin, Jörg; Lupas, Andrei N; Alva, Vikram

    2015-02-27

    Metalloproteases of the AAA (ATPases associated with various cellular activities) family play a crucial role in protein quality control within the cytoplasmic membrane of bacteria and the inner membrane of eukaryotic organelles. These membrane-anchored hexameric enzymes are composed of an N-terminal domain with one or two transmembrane helices, a central AAA ATPase module, and a C-terminal Zn(2+)-dependent protease. While the latter two domains have been well studied, so far, little is known about the N-terminal regions. Here, in an extensive bioinformatic and structural analysis, we identified three major, non-homologous groups of N-domains in AAA metalloproteases. By far, the largest one is the FtsH-like group of bacteria and eukaryotic organelles. The other two groups are specific to Yme1: one found in plants, fungi, and basal metazoans and the other one found exclusively in animals. Using NMR and crystallography, we determined the subunit structure and hexameric assembly of Escherichia coli FtsH-N, exhibiting an unusual α+β fold, and the conserved part of fungal Yme1-N from Saccharomyces cerevisiae, revealing a tetratricopeptide repeat fold. Our bioinformatic analysis showed that, uniquely among these proteins, the N-domain of Yme1 from the cnidarian Hydra vulgaris contains both the tetratricopeptide repeat region seen in basal metazoans and a region of homology to the N-domains of animals. Thus, it is a modern-day representative of an intermediate in the evolution of animal Yme1 from basal eukaryotic precursors. Copyright © 2015. Published by Elsevier Ltd.

  10. Covered Stent Grafts for Acquired Arterial Venous Fistulas: A Case Series.

    PubMed

    Sarac, Timur P; Vargas, Lina; Kashyap, Vikram; Cardella, Jonathan; Chaar, Cassius Ochoa

    2018-01-01

    Stent grafts have become the preferred method for treating abdominal aortic aneurysms (AAAs) but also have utility in treating other vasculopathies. In 2005, peripheral stent grafts were approved for treating superficial femoral artery occlusive disease. This report describes our experience using covered stent grafts to treat acquired arterial venous fistulae (aAVF). We reviewed the records of patients treated for aAVF with covered stent grafts. Eleven patients had 12 limbs treated with a stent graft. The data collected included presenting symptoms, mechanism of injury, vessel location, stent graft used for therapy, and patency. Eleven patients underwent successful treatment of 12 aAVF with a peripheral stent grafts. The average age was 55.6 (18-87), and there were 4 women and 7 men. The mechanisms of injuries were heart catheterization in 5 patients, penetrating trauma in 3 patients, and orthopedic injury in 3 patients. Five of the patients had concurrent pseudoaneurysms. Self-expanding expanded polytetrafluoroethelene (ePTFE) stent grafts were used in 8 patients, and balloon-expandable ePTFE stent grafts were used in 3 patients. Primary patency at 2 years is 100%, with all patients having significant relief of symptoms. Peripheral stent grafts are a useful tool for treating aAVF, with excellent patency. They provide a valuable minimally invasive approach to this disease. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Characterization of the Modular Design of the Autolysin/Adhesin Aaa from Staphylococcus Aureus

    PubMed Central

    Hirschhausen, Nina; Schlesier, Tim; Peters, Georg; Heilmann, Christine

    2012-01-01

    Background Staphylococcus aureus is a frequent cause of serious and life-threatening infections, such as endocarditis, osteomyelitis, pneumonia, and sepsis. Its adherence to various host structures is crucial for the establishment of diseases. Adherence may be mediated by a variety of adhesins, among them the autolysin/adhesins Atl and Aaa. Aaa is composed of three N-terminal repeated sequences homologous to a lysin motif (LysM) that can confer cell wall attachment and a C-terminally located cysteine, histidine-dependent amidohydrolase/peptidase (CHAP) domain having bacteriolytic activity in many proteins. Methodology/Principal Findings Here, we show by surface plasmon resonance that the LysM domain binds to fibrinogen, fibronectin, and vitronectin respresenting a novel adhesive function for this domain. Moreover, we demonstrated that the CHAP domain not only mediates the bacteriolytic activity, but also adherence to fibrinogen, fibronectin, and vitronectin, thus demonstrating for the first time an adhesive function for this domain. Adherence of an S. aureus aaa mutant and the complemented aaa mutant is slightly decreased and increased, respectively, to vitronectin, but not to fibrinogen and fibronectin, which might at least in part result from an increased expression of atl in the aaa mutant. Furthermore, an S. aureus atl mutant that showed enhanced adherence to fibrinogen, fibronectin, and endothelial cells also demonstrated increased aaa expression and production of Aaa. Thus, the redundant functions of Aaa and Atl might at least in part be interchangeable. Lastly, RT-PCR and zymographic analysis revealed that aaa is negatively regulated by the global virulence gene regulators agr and SarA. Conclusions/Significance We identified novel functions for two widely distributed protein domains, LysM and CHAP, i.e. the adherence to the extracellular matrix proteins fibrinogen, fibronectin, and vitronectin. The adhesive properties of Aaa might promote S. aureus

  12. Prior Radiological Investigations in 65-Year-Old Men Screened for AAA.

    PubMed

    Meecham, Lewis; Summerour, Virginia; Hobbs, Simon; Newman, Jeremy; Wall, Michael L

    2018-05-01

    The National Health Service abdominal aortic aneurysm screening programme (NAAASP) is now fully operational. Those who have previously been formally investigated for abdominal aortic aneurysm (AAA) are excluded; however, many patients undergo radiological investigation of the abdomen for other reasons. Such practices may find incidental AAA which may be eroding the performance of the NAAASP. We investigated the rates of preinvestigation before invitation to screening in our local AAA screening programme. Electronic patient records were retrospectively reviewed for all patients called between March 2013 and February 2016 in 1 local AAA screening programme. Their records were interrogated to identify any abdominal imaging within 5 years of their invitation to screening. Two thousand six hundred thirty-eight men were invited for screening; of these, 563 (21.3%) had been "prescreened". Median time between prescreening and screening was 19 months (0-60 months). Ultrasound abdomen was the most prevalent at 248 (44.0%). Two thousand two hundred forty-three (85.0%) men attended screening, and 6 (0.27%) were excluded for known AAA. Prevalence of AAA was 1.8% (n = 41). Of these, 15 (36.6%) had prior investigation with 6 (40.0%) having AAA diagnosed. Therefore, 9 (22.0%) had potential missed AAA on "prescreening" (mean diameter 35 mm [30-45], mean time lapse between investigation and screening 21.1 months [1-49]). Incidence of missed aneurysm in the "prescreened" cohort was 1.6% (9/563). Large numbers of men invited for AAA screening have undergone preinvestigation of their abdominal aorta, with 60% of the present AAA being missed. Reliance on incidental detection of AAA would leave many patients undiagnosed in the community-at risk of future rupture. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. Characterization of the modular design of the autolysin/adhesin Aaa from Staphylococcus aureus.

    PubMed

    Hirschhausen, Nina; Schlesier, Tim; Peters, Georg; Heilmann, Christine

    2012-01-01

    Staphylococcus aureus is a frequent cause of serious and life-threatening infections, such as endocarditis, osteomyelitis, pneumonia, and sepsis. Its adherence to various host structures is crucial for the establishment of diseases. Adherence may be mediated by a variety of adhesins, among them the autolysin/adhesins Atl and Aaa. Aaa is composed of three N-terminal repeated sequences homologous to a lysin motif (LysM) that can confer cell wall attachment and a C-terminally located cysteine, histidine-dependent amidohydrolase/peptidase (CHAP) domain having bacteriolytic activity in many proteins. Here, we show by surface plasmon resonance that the LysM domain binds to fibrinogen, fibronectin, and vitronectin respresenting a novel adhesive function for this domain. Moreover, we demonstrated that the CHAP domain not only mediates the bacteriolytic activity, but also adherence to fibrinogen, fibronectin, and vitronectin, thus demonstrating for the first time an adhesive function for this domain. Adherence of an S. aureus aaa mutant and the complemented aaa mutant is slightly decreased and increased, respectively, to vitronectin, but not to fibrinogen and fibronectin, which might at least in part result from an increased expression of atl in the aaa mutant. Furthermore, an S. aureus atl mutant that showed enhanced adherence to fibrinogen, fibronectin, and endothelial cells also demonstrated increased aaa expression and production of Aaa. Thus, the redundant functions of Aaa and Atl might at least in part be interchangeable. Lastly, RT-PCR and zymographic analysis revealed that aaa is negatively regulated by the global virulence gene regulators agr and SarA. We identified novel functions for two widely distributed protein domains, LysM and CHAP, i.e. the adherence to the extracellular matrix proteins fibrinogen, fibronectin, and vitronectin. The adhesive properties of Aaa might promote S. aureus colonization of host extracellular matrix and tissue, suggesting a role for

  14. Elbow replacement

    MedlinePlus

    ... arthroplasty Patient Instructions Elbow replacement - discharge Surgical wound care - open Images Elbow prosthesis References Cohen MS, Chen NC. Total elbow arthroplasty. In: Wolfe SW, Hotchkiss RN, Pederson ...

  15. Mechanism of Enzyme Repair by the AAA+ Chaperone Rubisco Activase.

    PubMed

    Bhat, Javaid Y; Miličić, Goran; Thieulin-Pardo, Gabriel; Bracher, Andreas; Maxwell, Andrew; Ciniawsky, Susanne; Mueller-Cajar, Oliver; Engen, John R; Hartl, F Ulrich; Wendler, Petra; Hayer-Hartl, Manajit

    2017-09-07

    How AAA+ chaperones conformationally remodel specific target proteins in an ATP-dependent manner is not well understood. Here, we investigated the mechanism of the AAA+ protein Rubisco activase (Rca) in metabolic repair of the photosynthetic enzyme Rubisco, a complex of eight large (RbcL) and eight small (RbcS) subunits containing eight catalytic sites. Rubisco is prone to inhibition by tight-binding sugar phosphates, whose removal is catalyzed by Rca. We engineered a stable Rca hexamer ring and analyzed its functional interaction with Rubisco. Hydrogen/deuterium exchange and chemical crosslinking showed that Rca structurally destabilizes elements of the Rubisco active site with remarkable selectivity. Cryo-electron microscopy revealed that Rca docks onto Rubisco over one active site at a time, positioning the C-terminal strand of RbcL, which stabilizes the catalytic center, for access to the Rca hexamer pore. The pulling force of Rca is fine-tuned to avoid global destabilization and allow for precise enzyme repair. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Multibands tunneling in AAA-stacked trilayer graphene

    NASA Astrophysics Data System (ADS)

    Redouani, Ilham; Jellal, Ahmed; Bahaoui, Abdelhadi; Bahlouli, Hocine

    2018-04-01

    We study the electronic transport through np and npn junctions for AAA-stacked trilayer graphene. Two kinds of gates are considered where the first is a single gate and the second is a double gate. After obtaining the solutions for the energy spectrum, we use the transfer matrix method to determine the three transmission probabilities for each individual cone τ = 0 , ± 1 . We show that the quasiparticles in AAA-stacked trilayer graphene are not only chiral but also labeled by an additional cone index τ. The obtained bands are composed of three Dirac cones that depend on the chirality indexes. We show that there is perfect transmission for normal or near normal incidence, which is a manifestation of the Klein tunneling effect. We analyze also the corresponding total conductance, which is defined as the sum of the conductance channels in each individual cone. Our results are numerically discussed and compared with those obtained for ABA- and ABC-stacked trilayer graphene.

  17. Analysis of a Typical Chinese High School Biology Textbook Using the AAAS Textbook Standards

    ERIC Educational Resources Information Center

    Liang, Ye; Cobern, William W.

    2013-01-01

    The purpose of this study was to evaluate a typical Chinese high school biology textbook using the textbook standards of the American Association for the Advancement of Science (AAAS). The data were composed of three chapters selected from the textbook. Each chapter was analyzed and rated using the AAAS textbook standards. Pearson correlations…

  18. APC-PCI complex levels for screening of AAA in patients with peripheral atherosclerosis.

    PubMed

    Zarrouk, Moncef; Keshavarz, Kave; Lindblad, Bengt; Gottsäter, Anders

    2013-11-01

    To evaluate the use of activated protein C-protein C inhibitor (APC-PCI) complex levels for detection of abdominal aortic aneurysm (AAA) in patients with peripheral atherosclerotic disease (PAD). APC-PCI levels and aortic diameter evaluated in 511 PAD patients without previously known AAA followed-up concerning survival for 4.8(0.5) years. AAA was found in 13% of patients. Aortic diameter correlated (r = 0.138; p = 0.002) with APC-PCI levels which were higher (0.40[0.45] vs. 0.30[0.49] μg/l; p = 0.004) in patients with AAA. This difference persisted in multivariate analysis (p = 0.029). A threshold value of APC-PCI ≥0.15 μg/L showed a specificity of 11%, a sensitivity of 97% and a negative predictive value of 96% for an AAA diagnosis. APC-PCI levels were higher in patients with AAA, and showed high sensitivity but low specificity for the diagnosis and can therefore not be considered as a screening tool in PAD patients. An AAA prevalence of 13% in patients with PAD indicates a need for AAA screening within this population.

  19. Biomarkers for AAA: Encouraging steps but clinical relevance still to be delivered.

    PubMed

    Htun, Nay Min; Peter, Karlheinz

    2014-10-01

    Potential biomarkers have been investigated using proteomic studies in a variety of diseases. Some biomarkers have central roles in both diagnosis and monitoring of various disorders in clinical medicine, such as troponins, brain natriuretic peptide, and C-reactive protein. Although several biomarkers have been suggested in human abdominal aortic aneurysm (AAA), reliable markers have been lacking. In this issue, Moxon et al. [Proteomics Clin Appl. 2014, 8, 762-772] undertook a broad and systematic proteomic approach toward identification of biomarkers in a commonly used AAA mouse model (AAA created by angiotensin-II infusion). In this mouse model, apolipoprotein C1 and matrix metalloproteinase-9 were identified as novel biomarkers of stable AAA. This finding represents an important step forward, toward a clinically relevant role of biomarkers in AAA. This also encourages for further studies toward the identification of biomarkers (or their combinations) that can predict AAA progression and rupture, which would represent a major progress in AAA management and would establish an AAA biomarker as a much anticipated clinical tool. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. HTTP as a Data Access Protocol: Trials with XrootD in CMS’s AAA Project

    NASA Astrophysics Data System (ADS)

    Balcas, J.; Bockelman, B. P.; Kcira, D.; Newman, H.; Vlimant, J.; Hendricks, T. W.; CMS Collaboration

    2017-10-01

    The main goal of the project to demonstrate the ability of using HTTP data federations in a manner analogous to the existing AAA infrastructure of the CMS experiment. An initial testbed at Caltech has been built and changes in the CMS software (CMSSW) are being implemented in order to improve HTTP support. The testbed consists of a set of machines at the Caltech Tier2 that improve the support infrastructure for data federations at CMS. As a first step, we are building systems that produce and ingest network data transfers up to 80 Gbps. In collaboration with AAA, HTTP support is enabled at the US redirector and the Caltech testbed. A plugin for CMSSW is being developed for HTTP access based on the DaviX software. It will replace the present fork/exec or curl for HTTP access. In addition, extensions to the XRootD HTTP implementation are being developed to add functionality to it, such as client-based monitoring identifiers. In the future, patches will be developed to better integrate HTTP-over-XRootD with the Open Science Grid (OSG) distribution. First results of the transfer tests using HTTP are presented in this paper together with details about the initial setup.

  1. Excellent Aesthetic and Functional Outcome After Fractionated Carbon Dioxide Laser Skin Graft Revision Surgery: Case Report and Review of Laser Skin Graft Revision Techniques.

    PubMed

    Ho, Derek; Jagdeo, Jared

    2015-11-01

    Skin grafts are utilized in dermatology to reconstruct a defect secondary to surgery or trauma of the skin. Common indications for skin grafts include surgical removal of cutaneous malignancies, replacement of tissue after burns or lacerations, and hair transplantation in alopecia. Skin grafts may be cosmetically displeasing, functionally limiting, and significantly impact patient's quality-of-life. There is limited published data regarding skin graft revision to enhance aesthetics and function. Here, we present a case demonstrating excellent aesthetic and functional outcome after fractionated carbon dioxide (CO2) laser skin graft revision surgery and review of the medical literature on laser skin graft revision techniques.

  2. Loss of Drosophila i-AAA protease, dYME1L, causes abnormal mitochondria and apoptotic degeneration.

    PubMed

    Qi, Y; Liu, H; Daniels, M P; Zhang, G; Xu, H

    2016-02-01

    Mitochondrial AAA (ATPases Associated with diverse cellular Activities) proteases i-AAA (intermembrane space-AAA) and m-AAA (matrix-AAA) are closely related and have major roles in inner membrane protein homeostasis. Mutations of m-AAA proteases are associated with neuromuscular disorders in humans. However, the role of i-AAA in metazoans is poorly understood. We generated a deletion affecting Drosophila i-AAA, dYME1L (dYME1L(del)). Mutant flies exhibited premature aging, progressive locomotor deficiency and neurodegeneration that resemble some key features of m-AAA diseases. dYME1L(del) flies displayed elevated mitochondrial unfolded protein stress and irregular cristae. Aged dYME1L(del) flies had reduced complex I (NADH/ubiquinone oxidoreductase) activity, increased level of reactive oxygen species (ROS), severely disorganized mitochondrial membranes and increased apoptosis. Furthermore, inhibiting apoptosis by targeting dOmi (Drosophila Htra2/Omi) or DIAP1, or reducing ROS accumulation suppressed retinal degeneration. Our results suggest that i-AAA is essential for removing unfolded proteins and maintaining mitochondrial membrane architecture. Loss of i-AAA leads to the accumulation of oxidative damage and progressive deterioration of membrane integrity, which might contribute to apoptosis upon the release of proapoptotic molecules such as dOmi. Containing ROS level could be a potential strategy to manage mitochondrial AAA protease deficiency.

  3. Knee Replacement

    MedlinePlus

    ... a knee replacement is right for you, an orthopedic surgeon assesses your knee's range of motion, stability ... trademarks of Mayo Foundation for Medical Education and Research. © 1998-2018 Mayo Foundation for Medical Education and ...

  4. Shoulder replacement

    MedlinePlus

    ... the opening at the end of the shoulder blade, called the socket. This type of joint allows ... head. The socket part (glenoid) of your shoulder blade will be replaced with a smooth plastic shell ( ...

  5. Successful Antibiotic Treatment of Severe Staphylococcal Infection of a Long Stent Graft in the Superficial Femoral Artery with Graft Preservation in the Long Term

    SciTech Connect

    Treitl, Marcus, E-mail: Marcus.Treitl@med.uni-muenchen.de; Rademacher, Antje; Becker-Lienau, Johanna

    2011-06-15

    Introduction: Bacterial infection of endovascular stent grafts is a serious condition, regularly leading to graft replacement by open bypass surgery.Case ReportWe describe the case of a staphylococcal infection of a 150-mm covered stent graft (Gore Viabahn), placed in the superficial femoral artery. Stent graft infection was successfully treated by oral administration of penicillinase-resistant flucloxacillin and the lipopeptide daptomycin with complete graft preservation, not requiring surgical treatment. During 1-year follow-up, the graft infection did not reappear. However, the patient developed restenosis at the proximal margin of the stent with recurrence of mild claudication, so far treated conservatively. Conclusion: With the increasedmore » use of covered stent grafts in the peripheral vasculature, the frequency of graft infection will increase. We demonstrate that with newly developed antibiotics, it is possible to treat this severe complication conservatively, with complete graft preservation and without the need for bypass surgery in selected cases.« less

  6. Electrostrictive Graft Elastomers

    NASA Technical Reports Server (NTRS)

    Su, Ji (Inventor); Harrison, Joycelyn S. (Inventor); St.Clair, Terry L. (Inventor)

    2003-01-01

    An electrostrictive graft elastomer has a backbone molecule which is a non-crystallizable, flexible macromolecular chain and a grafted polymer forming polar graft moieties with backbone molecules. The polar graft moieties have been rotated by an applied electric field, e.g., into substantial polar alignment. The rotation is sustained until the electric field is removed. In another embodiment, a process for producing strain in an elastomer includes: (a) providing a graft elastomer having a backbone molecule which is a non-crystallizable, flexible macromolecular chain and a grafted polymer forming polar graft moieties with backbone molecules; and (b) applying an electric field to the graft elastomer to rotate the polar graft moieties, e.g., into substantial polar alignment.

  7. Mitochondrial AAA proteases--towards a molecular understanding of membrane-bound proteolytic machines.

    PubMed

    Gerdes, Florian; Tatsuta, Takashi; Langer, Thomas

    2012-01-01

    Mitochondrial AAA proteases play an important role in the maintenance of mitochondrial proteostasis. They regulate and promote biogenesis of mitochondrial proteins by acting as processing enzymes and ensuring the selective turnover of misfolded proteins. Impairment of AAA proteases causes pleiotropic defects in various organisms including neurodegeneration in humans. AAA proteases comprise ring-like hexameric complexes in the mitochondrial inner membrane and are functionally conserved from yeast to man, but variations are evident in the subunit composition of orthologous enzymes. Recent structural and biochemical studies revealed how AAA proteases degrade their substrates in an ATP dependent manner. Intersubunit coordination of the ATP hydrolysis leads to an ordered ATP hydrolysis within the AAA ring, which ensures efficient substrate dislocation from the membrane and translocation to the proteolytic chamber. In this review, we summarize recent findings on the molecular mechanisms underlying the versatile functions of mitochondrial AAA proteases and their relevance to those of the other AAA+ machines. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Implantation of Vascular Grafts Lined with Genetically Modified Endothelial Cells

    NASA Astrophysics Data System (ADS)

    Wilson, James M.; Birinyi, Louis K.; Salomon, Robert N.; Libby, Peter; Callow, Allan D.; Mulligan, Richard C.

    1989-06-01

    The possibility of using the vascular endothelial cell as a target for gene replacement therapy was explored. Recombinant retroviruses were used to transduce the lacZ gene into endothelial cells harvested from mongrel dogs. Prosthetic vascular grafts seeded with the genetically modified cells were implanted as carotid interposition grafts into the dogs from which the original cells were harvested. Analysis of the graft 5 weeks after implantation revealed genetically modified endothelial cells lining the luminal surface of the graft. This technology could be used in the treatment of atherosclerosis disease and the design of new drug delivery systems.

  9. Multi-Centre Study on Cardiovascular Risk Management on Patients Undergoing AAA Surveillance.

    PubMed

    Saratzis, A; Dattani, N; Brown, A; Shalhoub, J; Bosanquet, D; Sidloff, D; Stather, P

    2017-07-01

    The risk of cardiovascular events and death in patients with abdominal aortic aneurysms (AAA) is high. Screening has been introduced to reduce AAA related mortality; however, after AAA diagnosis, cardiovascular modification may be as important to patient outcomes as surveillance. The aim of this study was to assess cardiovascular risk reduction in patients with small AAA. Institutional approval was granted for The Vascular and Endovascular Research Network (VERN) to retrospectively collect data pertaining to cardiovascular risk reduction from four tertiary vascular units in England. Patients with small AAA (January 2013-December 2015) were included. Demographic details, postcode, current medications, and smoking status were recorded using a bespoke electronic database and analysed. In a secondary analysis VERN contacted all AAA screening units in England and Wales to assess their current protocols relating to CV protection. In total, 1053 patients were included (mean age 74 ± 9 years, all men). Of these, 745 patients (70.8%) had been prescribed an antiplatelet agent and 787 (74.7%) a statin. Overall, only 666 patients (63.2%) were prescribed both a statin and antiplatelet. Two hundred and sixty eight patients (32.1%) were current smokers and the proportion of patients who continued to smoke decreased with age. Overall, only 401 patients (48.1%) were prescribed a statin, antiplatelet, and had stopped smoking. In the secondary analysis 38 AAA screening units (84% national coverage) replied. Thirty-one units (82%) suggest changes to the patient's prescription; however, none monitor compliance with these recommendations or assess whether the general practitioner has been made aware of the AAA diagnosis or prescription advice. Many patients with small AAA are not prescribed an antiplatelet/statin, and still smoke cigarettes, and therefore remain at high risk of cardiovascular morbidity and mortality. National guidance to ensure this high risk group of patients is

  10. Esophageal replacement.

    PubMed

    Kunisaki, Shaun M; Coran, Arnold G

    2017-04-01

    This article focuses on esophageal replacement as a surgical option for pediatric patients with end-stage esophageal disease. While it is obvious that the patient׳s own esophagus is the best esophagus, persisting with attempts to retain a native esophagus with no function and at all costs are futile and usually detrimental to the overall well-being of the child. In such cases, the esophagus should be abandoned, and the appropriate esophageal replacement is chosen for definitive reconstruction. We review the various types of conduits used for esophageal replacement and discuss the unique advantages and disadvantages that are relevant for clinical decision-making. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Skin graft - slideshow

    MedlinePlus

    ... 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 ...

  12. Gum Graft Surgery

    MedlinePlus

    ... gum line and reduce sensitivity. What are the benefits of gum graft surgery? A gum graft can ... improve function or esthetics, patients often receive the benefits of both: a beautiful new smile and improved ...

  13. Modification of an endovascular stent graft for abdominal aortic aneurysm

    NASA Astrophysics Data System (ADS)

    Moloye, Olajompo Busola

    Endovascular surgery is currently used to treat abdominal aortic aneurysms (AAA). A stent graft is deployed to exclude blood flow from the aneurysm sac. It is an effective procedure used in preventing aneurysm rupture, with reduced patient morbidity and mortality compared to open surgical repair. Migration and leakage around the device ("endoleak") due to poor sealing of the stent graft to the aorta have raised concerns about the long-term durability of endovascular repair. A preliminary study of cell migration and proliferation is presented as a prelude to a more extensive in vivo testing. A method to enhance the biological seal between the stent graft and the aorta is proposed to eliminate this problem. This can be achieved by impregnating the stent graft with 50/50 poly (DL-lactide co glycolic acid) (PLGA) and growth factors such as basic fibroblast growth factor (bFGF) or connective tissue growth factor (CTGF), at the proximal and distal ends. It is hypothesized that as PLGA degrades it will release the growth factors that will promote proliferation and migration of aortic smooth muscle cells to the coated site, leading to a natural seal between the aorta and the stent graft. In addition, growth factor release should promote smooth muscle cell (SMC) contraction that will help keep the stent graft in place at the proximal and distal ends. It is shown that a statistically significant effect of increased cell proliferation and migration is observed for CTGF release. Less of an effect is noted for bFGF or just the PLGA. The effect is estimated to be large enough to be clinically significant in a future animal study. The long term goal of this study is to reduce migration encounter after graft deployment and to reduce secondary interventions of EVAR especially for older patients who are unfit for open surgical treatment.

  14. Dosimetric comparison of peripheral NSCLC SBRT using Acuros XB and AAA calculation algorithms.

    PubMed

    Ong, Chloe C H; Ang, Khong Wei; Soh, Roger C X; Tin, Kah Ming; Yap, Jerome H H; Lee, James C L; Bragg, Christopher M

    2017-01-01

    There is a concern for dose calculation in highly heterogenous environments such as the thorax region. This study compares the quality of treatment plans of peripheral non-small cell lung cancer (NSCLC) stereotactic body radiation therapy (SBRT) using 2 calculation algorithms, namely, Eclipse Anisotropic Analytical Algorithm (AAA) and Acuros External Beam (AXB), for 3-dimensional conformal radiation therapy (3DCRT) and volumetric-modulated arc therapy (VMAT). Four-dimensional computed tomography (4DCT) data from 20 anonymized patients were studied using Varian Eclipse planning system, AXB, and AAA version 10.0.28. A 3DCRT plan and a VMAT plan were generated using AAA and AXB with constant plan parameters for each patient. The prescription and dose constraints were benchmarked against Radiation Therapy Oncology Group (RTOG) 0915 protocol. Planning parameters of the plan were compared statistically using Mann-Whitney U tests. Results showed that 3DCRT and VMAT plans have a lower target coverage up to 8% when calculated using AXB as compared with AAA. The conformity index (CI) for AXB plans was 4.7% lower than AAA plans, but was closer to unity, which indicated better target conformity. AXB produced plans with global maximum doses which were, on average, 2% hotter than AAA plans. Both 3DCRT and VMAT plans were able to achieve D95%. VMAT plans were shown to be more conformal (CI = 1.01) and were at least 3.2% and 1.5% lower in terms of PTV maximum and mean dose, respectively. There was no statistically significant difference for doses received by organs at risk (OARs) regardless of calculation algorithms and treatment techniques. In general, the difference in tissue modeling for AXB and AAA algorithm is responsible for the dose distribution between the AXB and the AAA algorithms. The AXB VMAT plans could be used to benefit patients receiving peripheral NSCLC SBRT. Copyright © 2017 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights

  15. The peroxisomal AAA ATPase complex prevents pexophagy and development of peroxisome biogenesis disorders

    PubMed Central

    Law, Kelsey B.; Bronte-Tinkew, Dana; Di Pietro, Erminia; Snowden, Ann; Jones, Richard O.; Moser, Ann; Brumell, John H.; Braverman, Nancy

    2017-01-01

    ABSTRACT Peroxisome biogenesis disorders (PBDs) are metabolic disorders caused by the loss of peroxisomes. The majority of PBDs result from mutation in one of 3 genes that encode for the peroxisomal AAA ATPase complex (AAA-complex) required for cycling PEX5 for peroxisomal matrix protein import. Mutations in these genes are thought to result in a defect in peroxisome assembly by preventing the import of matrix proteins. However, we show here that loss of the AAA-complex does not prevent matrix protein import, but instead causes an upregulation of peroxisome degradation by macroautophagy, or pexophagy. The loss of AAA-complex function in cells results in the accumulation of ubiquitinated PEX5 on the peroxisomal membrane that signals pexophagy. Inhibiting autophagy by genetic or pharmacological approaches rescues peroxisome number, protein import and function. Our findings suggest that the peroxisomal AAA-complex is required for peroxisome quality control, whereas its absence results in the selective degradation of the peroxisome. Thus the loss of peroxisomes in PBD patients with mutations in their peroxisomal AAA-complex is a result of increased pexophagy. Our study also provides a framework for the development of novel therapeutic treatments for PBDs. PMID:28521612

  16. The peroxisomal AAA ATPase complex prevents pexophagy and development of peroxisome biogenesis disorders.

    PubMed

    Law, Kelsey B; Bronte-Tinkew, Dana; Di Pietro, Erminia; Snowden, Ann; Jones, Richard O; Moser, Ann; Brumell, John H; Braverman, Nancy; Kim, Peter K

    2017-05-04

    Peroxisome biogenesis disorders (PBDs) are metabolic disorders caused by the loss of peroxisomes. The majority of PBDs result from mutation in one of 3 genes that encode for the peroxisomal AAA ATPase complex (AAA-complex) required for cycling PEX5 for peroxisomal matrix protein import. Mutations in these genes are thought to result in a defect in peroxisome assembly by preventing the import of matrix proteins. However, we show here that loss of the AAA-complex does not prevent matrix protein import, but instead causes an upregulation of peroxisome degradation by macroautophagy, or pexophagy. The loss of AAA-complex function in cells results in the accumulation of ubiquitinated PEX5 on the peroxisomal membrane that signals pexophagy. Inhibiting autophagy by genetic or pharmacological approaches rescues peroxisome number, protein import and function. Our findings suggest that the peroxisomal AAA-complex is required for peroxisome quality control, whereas its absence results in the selective degradation of the peroxisome. Thus the loss of peroxisomes in PBD patients with mutations in their peroxisomal AAA-complex is a result of increased pexophagy. Our study also provides a framework for the development of novel therapeutic treatments for PBDs.

  17. Abdominal aorta aneurysm (AAA): Is there a role for prevention and therapy using antioxidants?

    PubMed

    Pincemail, Joël; Defraigne, Jean-Olivier; Courtois, Audrey; Albert, Adelin; Cheramy-Bien, Jean-Paul; Sakalihasan, Natzi

    2017-09-18

    Abdominal aortic aneurysm (AAA) is a degenerative disease that cause mortality in people aged > 65 years. Increased reactive oxygen species (ROS) and oxidative stress seems to play a pivotal role in AAA pathogenesis. Several sources of ROS have been identified in aortic tissues using experimental models: inflammation, increased activity of NAD(P)H or NOX, over-expression of inducible nitric oxide synthase (iNOS), uncoupled endothelial nitric oxide synthase (eNOS), platelets activation and iron release from hemoglobin. Reducing oxidative stress by antioxidants has been shown to be a potential strategy for limiting AAA development. Human studies confirmed that oxidative stress and endothelial dysfunction are well associated with AAA development. Unfortunately, there is currently no evidence showing that strategies using low molecular weight antioxidants (vitamins C and E, β-carotene) as target for ROS is effective to reduce human AAA progression. However, recent epidemiological data have highlighted the positive role of a diet enriched in fruits which contain high amounts of antioxidant polyphenols. By their ability to restore endothelial function but also their capacity to stimulate enzymatic antioxidants trough activation of the Keap1/Nrf2/ARE pathway, polyphenols can represent a promising treatment target for reducing human AAA progression. Clinical studies are therefore urgently necessary to confirm such a suggestion. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  18. The m-AAA Protease Associated with Neurodegeneration Limits MCU Activity in Mitochondria.

    PubMed

    König, Tim; Tröder, Simon E; Bakka, Kavya; Korwitz, Anne; Richter-Dennerlein, Ricarda; Lampe, Philipp A; Patron, Maria; Mühlmeister, Mareike; Guerrero-Castillo, Sergio; Brandt, Ulrich; Decker, Thorsten; Lauria, Ines; Paggio, Angela; Rizzuto, Rosario; Rugarli, Elena I; De Stefani, Diego; Langer, Thomas

    2016-10-06

    Mutations in subunits of mitochondrial m-AAA proteases in the inner membrane cause neurodegeneration in spinocerebellar ataxia (SCA28) and hereditary spastic paraplegia (HSP7). m-AAA proteases preserve mitochondrial proteostasis, mitochondrial morphology, and efficient OXPHOS activity, but the cause for neuronal loss in disease is unknown. We have determined the neuronal interactome of m-AAA proteases in mice and identified a complex with C2ORF47 (termed MAIP1), which counteracts cell death by regulating the assembly of the mitochondrial Ca 2+ uniporter MCU. While MAIP1 assists biogenesis of the MCU subunit EMRE, the m-AAA protease degrades non-assembled EMRE and ensures efficient assembly of gatekeeper subunits with MCU. Loss of the m-AAA protease results in accumulation of constitutively active MCU-EMRE channels lacking gatekeeper subunits in neuronal mitochondria and facilitates mitochondrial Ca 2+ overload, mitochondrial permeability transition pore opening, and neuronal death. Together, our results explain neuronal loss in m-AAA protease deficiency by deregulated mitochondrial Ca 2+ homeostasis. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Determining the influence of calcification on the failure properties of abdominal aortic aneurysm (AAA) tissue.

    PubMed

    O'Leary, Siobhan A; Mulvihill, John J; Barrett, Hilary E; Kavanagh, Eamon G; Walsh, Michael T; McGloughlin, Tim M; Doyle, Barry J

    2015-02-01

    Varying degrees of calcification are present in most abdominal aortic aneurysms (AAAs). However, their impact on AAA failure properties and AAA rupture risk is unclear. The aim of this work is evaluate and compare the failure properties of partially calcified and predominantly fibrous AAA tissue and investigate the potential reasons for failure. Uniaxial mechanical testing was performed on AAA samples harvested from 31 patients undergoing open surgical repair. Individual tensile samples were divided into two groups: fibrous (n=31) and partially calcified (n=38). The presence of calcification was confirmed by fourier transform infrared spectroscopy (FTIR). A total of 69 mechanical tests were performed and the failure stretch (λf), failure stress (σf) and failure tension (Tf) were recorded for each test. Following mechanical testing, the failure sites of a subset of both tissue types were examined using scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS) to investigate the potential reasons for failure. It has been shown that the failure properties of partially calcified tissue are significantly reduced compared to fibrous tissue and SEM and EDS results suggest that the junction between a calcification deposit and the fibrous matrix is highly susceptible to failure. This study implicates the presence of calcification as a key player in AAA rupture risk and provides further motivation for the development of non-invasive methods of measuring calcification. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. An AAA-DDD triply hydrogen-bonded complex easily accessible for supramolecular polymers.

    PubMed

    Han, Yi-Fei; Chen, Wen-Qiang; Wang, Hong-Bo; Yuan, Ying-Xue; Wu, Na-Na; Song, Xiang-Zhi; Yang, Lan

    2014-12-15

    For a complementary hydrogen-bonded complex, when every hydrogen-bond acceptor is on one side and every hydrogen-bond donor is on the other, all secondary interactions are attractive and the complex is highly stable. AAA-DDD (A=acceptor, D=donor) is considered to be the most stable among triply hydrogen-bonded sequences. The easily synthesized and further derivatized AAA-DDD system is very desirable for hydrogen-bonded functional materials. In this case, AAA and DDD, starting from 4-methoxybenzaldehyde, were synthesized with the Hantzsch pyridine synthesis and Friedländer annulation reaction. The association constant determined by fluorescence titration in chloroform at room temperature is 2.09×10(7)  M(-1) . The AAA and DDD components are not coplanar, but form a V shape in the solid state. Supramolecular polymers based on AAA-DDD triply hydrogen bonded have also been developed. This work may make AAA-DDD triply hydrogen-bonded sequences easily accessible for stimuli-responsive materials. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. The Mitochondrial m-AAA Protease Prevents Demyelination and Hair Greying.

    PubMed

    Wang, Shuaiyu; Jacquemyn, Julie; Murru, Sara; Martinelli, Paola; Barth, Esther; Langer, Thomas; Niessen, Carien M; Rugarli, Elena I

    2016-12-01

    The m-AAA protease preserves proteostasis of the inner mitochondrial membrane. It ensures a functional respiratory chain, by controlling the turnover of respiratory complex subunits and allowing mitochondrial translation, but other functions in mitochondria are conceivable. Mutations in genes encoding subunits of the m-AAA protease have been linked to various neurodegenerative diseases in humans, such as hereditary spastic paraplegia and spinocerebellar ataxia. While essential functions of the m-AAA protease for neuronal survival have been established, its role in adult glial cells remains enigmatic. Here, we show that deletion of the highly expressed subunit AFG3L2 in mature mouse oligodendrocytes provokes early-on mitochondrial fragmentation and swelling, as previously shown in neurons, but causes only late-onset motor defects and myelin abnormalities. In contrast, total ablation of the m-AAA protease, by deleting both Afg3l2 and its paralogue Afg3l1, triggers progressive motor dysfunction and demyelination, owing to rapid oligodendrocyte cell death. Surprisingly, the mice showed premature hair greying, caused by progressive loss of melanoblasts that share a common developmental origin with Schwann cells and are targeted in our experiments. Thus, while both neurons and glial cells are dependant on the m-AAA protease for survival in vivo, complete ablation of the complex is necessary to trigger death of oligodendrocytes, hinting to cell-autonomous thresholds of vulnerability to m-AAA protease deficiency.

  2. The AAA+ ATPase p97, a cellular multitool

    PubMed Central

    Stach, Lasse

    2017-01-01

    The AAA+ (ATPases associated with diverse cellular activities) ATPase p97 is essential to a wide range of cellular functions, including endoplasmic reticulum-associated degradation, membrane fusion, NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) activation and chromatin-associated processes, which are regulated by ubiquitination. p97 acts downstream from ubiquitin signaling events and utilizes the energy from ATP hydrolysis to extract its substrate proteins from cellular structures or multiprotein complexes. A multitude of p97 cofactors have evolved which are essential to p97 function. Ubiquitin-interacting domains and p97-binding domains combine to form bi-functional cofactors, whose complexes with p97 enable the enzyme to interact with a wide range of ubiquitinated substrates. A set of mutations in p97 have been shown to cause the multisystem proteinopathy inclusion body myopathy associated with Paget's disease of bone and frontotemporal dementia. In addition, p97 inhibition has been identified as a promising approach to provoke proteotoxic stress in tumors. In this review, we will describe the cellular processes governed by p97, how the cofactors interact with both p97 and its ubiquitinated substrates, p97 enzymology and the current status in developing p97 inhibitors for cancer therapy. PMID:28819009

  3. Stent grafts for the treatment of abdominal aortic aneurysms.

    PubMed

    Diethrich, Edward B

    2003-01-01

    Stent grafting for treatment of abdominal aortic aneurysms (AAAs) has been a major advance in endovascular surgery. Initial success with the original endoluminal stent graft encouraged worldwide study of the technology. In the United States, the Food and Drug Administration (FDA) insisted on considerable experience with the devices before approval because of early problems with device rupture, stent fracture, fabric perforation, graft migration, and modular separation. Complications associated with the endovascular graft technology led many to recommend its use only in patients who were considered at "high risk" for the standard, open procedure. Further study and device improvements have led to results that indicate the procedure has the potential to reduce operating time and blood loss and shorten intensive care unit and hospital stays compared with open surgical intervention. At present, there are three FDA-approved devices available for use, and a fourth is expected in 2003. The ultimate decision by the individual practitioner or the institutional team regarding which patients should be treated with endovascular technology is still not entirely straightforward. Patient selection should be based on vascular anatomy, the availability of a suitable device, the patient's desire for a minimally invasive procedure, and a commitment to what is likely to be a lifetime of device surveillance.

  4. Fourteen-year outcomes of abdominal aortic endovascular repair with the Zenith stent graft.

    PubMed

    Verzini, Fabio; Romano, Lydia; Parlani, Gianbattista; Isernia, Giacomo; Simonte, Gioele; Loschi, Diletta; Lenti, Massimo; Cao, Piergiorgio

    2017-02-01

    Long-term results of abdominal aortic aneurysm (AAA) endovascular repair are affected by graft design renewals that tend to improve the performance of older generation prostheses but usually reset the follow-up times to zero. The present study investigated the long-term outcomes of endovascular AAA repair (EVAR) using the Zenith graft, still in use without major modification, in a single center experience. Between 2000 and 2011, 610 patients underwent elective EVAR using the Zenith endograft (Cook Inc, Bloomington, Ind) and represent the study group. Primary outcomes were overall survival, freedom from AAA rupture, and freedom from AAA-related death. Secondary outcomes included freedom from late (>30 days) reintervention, freedom from late (>30 days) conversion to open repair, freedom from aneurysm sac enlargement >5.0 mm and freedom from EVAR failure, defined as a composite of AAA-related death, AAA rupture, AAA growth >5 mm, and any reintervention. Mean age was 73.2 years. Mean aneurysm diameter was 55.3 mm. There were five perioperative deaths (0.8%) and three intraoperative conversions. At a mean follow-up of 99.2 (range, 0-175) months, seven AAA ruptures occurred, all fatal except one. Overall survival was 92.8% ± 1.1% at 1 year, 70.1% ± 1.9% at 5 years, 37.8% ± 2.9% at 10 years, and 24 ± 4% at 14 years. Freedom from AAA-rupture was 99.8% ± 0.02 at 1 year (one case), 99.4% ± 0.04 at 5 years (three cases), and 98.1% ± 0.07 at 10 and 14 years. Freedom from late reintervention and conversion was 98% ± 0.6 at 1 year, 87.7% ± 1.5 at 5 years, 75.7% ± 3.2 at 10 years, and 69.9% ± 5.2 at 14 years. Freedom from aneurysm sac growth >5.0 mm was 99.8% at 1 year, 96.6% ± 0.7 at 5 years, 81.0% ± 3.4 at 10 years, and 74.1% ± 5.8% at 14 years. EVAR failure occurred in 132 (21.6%) patients at 14 years. At multivariate analysis, independent predictors of EVAR failure resulted type I and III endoleak (hazard ratio [HR], 6.7; 95

  5. m-AAA and i-AAA complexes coordinate to regulate OMA1, the stress-activated supervisor of mitochondrial dynamics.

    PubMed

    Consolato, Francesco; Maltecca, Francesca; Tulli, Susanna; Sambri, Irene; Casari, Giorgio

    2018-04-09

    The proteolytic processing of dynamin-like GTPase OPA1, mediated by the activity of both YME1L1 [intermembrane (i)-AAA protease complex] and OMA1, is a crucial step in the regulation of mitochondrial dynamics. OMA1 is a zinc metallopeptidase of the inner mitochondrial membrane that undergoes pre-activating proteolytic and auto-proteolytic cleavage after mitochondrial import. Here, we identify AFG3L2 [matrix (m) - AAA complex] as the major protease mediating this event, which acts by maturing the 60 kDa pre-pro-OMA1 to the 40 kDa pro-OMA1 form by severing the N-terminal portion without recognizing a specific consensus sequence. Therefore, m - AAA and i - AAA complexes coordinately regulate OMA1 processing and turnover, and consequently control which OPA1 isoforms are present, thus adding new information on the molecular mechanisms of mitochondrial dynamics and neurodegenerative diseases affected by these phenomena.This article has an associated First Person interview with the first author of the paper. © 2018. Published by The Company of Biologists Ltd.

  6. Regionalization of Emergent Vascular Surgery for Patients With Ruptured AAA Improves Outcomes.

    PubMed

    Warner, Courtney J; Roddy, Sean P; Chang, Benjamin B; Kreienberg, Paul B; Sternbach, Yaron; Taggert, John B; Ozsvath, Kathleen J; Stain, Steven C; Darling, R Clement

    2016-09-01

    Safe and efficient endovascular aneurysm repair (EVAR) for ruptured abdominal aortic aneurysm (r-AAA) requires advanced infrastructure and surgical expertise not available at all US hospitals. The objective was to assess the impact of regionalizing r-AAA care to centers equipped for both open surgical repair (r-OSR) and EVAR (r-EVAR) by vascular surgeons. A retrospective review of all patients with r-AAA undergoing open or endovascular repair in a 12-hospital region. Patient demographics, transfer status, type of repair, and intraoperative variables were recorded. Outcomes included perioperative morbidity and mortality. Four hundred fifty-one patients with r-AAA were treated from 2002 to 2015. Three hundred twenty-one patients (71%) presented initially to community hospitals (CHs) and 130 (29%) presented to the tertiary medical center (MC). Of the 321 patients presenting to CH, 133 (41%) were treated locally (131 OSR; 2 EVAR) and 188 (59%) were transferred to the MC. In total, 318 patients were treated at the MC (122 OSR; 196 EVAR). At the MC, r-EVAR was associated with a lower mortality rate than r-OSR (20% vs 37%, P = 0.001). Transfer did not influence r-EVAR mortality (20% in r-EVAR presenting to MC vs 20% in r-EVAR transferred, P > 0.2). Overall, r-AAA mortality at the MC was 20% lower than CH (27% vs 46%, P < 0.001). Regionalization of r-AAA repair to centers equipped for both r-EVAR and r-OSR decreased mortality by approximately 20%. Transfer did not impact the mortality of r-EVAR at the tertiary center. Care of r-AAA in the US should be centralized to centers equipped with available technology and vascular surgeons.

  7. On the Impact of Intraluminal Thrombus Mechanical Behavior in AAA Passive Mechanics.

    PubMed

    Riveros, Fabián; Martufi, Giampaolo; Gasser, T Christian; Rodriguez-Matas, Jose F

    2015-09-01

    Intraluminal thrombus (ILT) is a pseudo-tissue that develops from coagulated blood, and is found in most abdominal aortic aneurysms (AAAs) of clinically relevant size. A number of studies have suggested that ILT mechanical characteristics may be related to AAA risk of rupture, even though there is still great controversy in this regard. ILT is isotropic and inhomogeneous and may appear as a soft (single-layered) or stiff (multilayered fibrotic) tissue. This paper aims to investigate how ILT constitution and topology influence the magnitude and location of peak wall stress (PWS). In total 21 patient-specific AAAs (diameter 4.2-5.4 cm) were reconstructed from computer tomography images and biomechanically analyzed using state-of-the-art modeling assumptions. Results indicated that PWS correlated stronger with ILT volume (ρ = 0.44, p = 0.05) and minimum thickness of ILT layer (ρ = 0.73, p = 0.001) than with maximum AAA diameter (ρ = 0.05, p = 0.82). On average PWS was 20% (SD 12%) higher for FE models that used soft instead of stiff ILT models (p < 0.001). PWS location strongly correlated with sites of minimum ILT thickness in the section of maximum AAA diameter and was independent from ILT stiffness. In addition, ILT heterogeneity, i.e., the spatial composition of soft and stiff thrombus tissue, can considerably influence stress in the AAA wall. The present study is limited to identification of influential biomechanical factors, and how its findings translate to an AAA rupture risk assessment remains to be explored by clinical studies.

  8. Esophageal replacement in children: Challenges and long-term outcomes.

    PubMed

    Soccorso, Giampiero; Parikh, Dakshesh H

    2016-01-01

    Replacement of a nonexistent or damaged esophagus continues to pose a significant challenge to pediatric surgeons. Various esophageal replacement grafts and techniques have not produced consistently good outcomes to emulate normal esophagus. Therefore, many techniques are still being practiced and recommended with no clear consensus. We present a concise literature review of the currently used techniques and with discussions on the advantages and anticipated morbidity. There are no randomized controlled pediatric studies to compare different types of esophageal replacements. Management and graft choice are based on geographical and personal predilections rather than on any discernible objective data. The biggest series with long-term outcome are reported for gastric transposition and colonic replacement. Comparison of different studies shows no significant difference in early (graft necrosis and anastomotic leaks) or late complications (strictures, poor feeding, gastro-esophageal reflux, tortuosity of the graft, and Barrett's esophagus). The biggest series seem to have lower complications than small series reflecting the decennials experience in their respective centers. Long-term follow-up is recommended following esophageal replacement for the development of late strictures, excessive tortuosity, and Barrett's changes within the graft. Once child overcomes initial morbidity and establishes oral feeding, long-term consequences and complications of pediatric esophageal replacement should be monitored and managed in adult life.

  9. Esophageal replacement in children: Challenges and long-term outcomes

    PubMed Central

    Soccorso, Giampiero; Parikh, Dakshesh H.

    2016-01-01

    Replacement of a nonexistent or damaged esophagus continues to pose a significant challenge to pediatric surgeons. Various esophageal replacement grafts and techniques have not produced consistently good outcomes to emulate normal esophagus. Therefore, many techniques are still being practiced and recommended with no clear consensus. We present a concise literature review of the currently used techniques and with discussions on the advantages and anticipated morbidity. There are no randomized controlled pediatric studies to compare different types of esophageal replacements. Management and graft choice are based on geographical and personal predilections rather than on any discernible objective data. The biggest series with long-term outcome are reported for gastric transposition and colonic replacement. Comparison of different studies shows no significant difference in early (graft necrosis and anastomotic leaks) or late complications (strictures, poor feeding, gastro-esophageal reflux, tortuosity of the graft, and Barrett's esophagus). The biggest series seem to have lower complications than small series reflecting the decennials experience in their respective centers. Long-term follow-up is recommended following esophageal replacement for the development of late strictures, excessive tortuosity, and Barrett's changes within the graft. Once child overcomes initial morbidity and establishes oral feeding, long-term consequences and complications of pediatric esophageal replacement should be monitored and managed in adult life. PMID:27365900

  10. Structural basis for the ATP-independent proteolytic activity of LonB proteases and reclassification of their AAA+ modules.

    PubMed

    An, Young Jun; Na, Jung-Hyun; Kim, Myung-Il; Cha, Sun-Shin

    2015-10-01

    Lon proteases degrade defective or denature proteins as well as some folded proteins for the control of cellular protein quality. There are two types of Lon proteases, LonA and LonB. Each consists of two functional components: a protease component and an ATPase associated with various cellular activities (AAA+ module). Here, we report the 2.03 -resolution crystal structure of the isolated AAA+ module (iAAA+ module) of LonB from Thermococcus onnurineus NA1 (TonLonB). The iAAA+ module, having no bound nucleotide, adopts a conformation virtually identical to the ADP-bound conformation of AAA+ modules in the hexameric structure of TonLonB; this provides insights into the ATP-independent proteolytic activity observed in a LonB protease. Structural comparison of AAA+ modules between LonA and LonB revealed that the AAA+ modules of Lon proteases are separated into two distinct clades depending on their structural features. The AAA+ module of LonB belongs to the -H2 & Ins1 insert clade (HINS clade)- defined for the first time in this study, while the AAA+ module of LonA is a member of the HCLR clade.

  11. An improved methodology for investigating the parameters influencing migration resistance of abdominal aortic stent-grafts.

    PubMed

    Corbett, Timothy J; Callanan, Anthony; O'Donnell, Michael R; McGloughlin, Tim M

    2010-02-01

    To develop an improved methodology for investigating the parameters influencing stent-graft migration, with particular focus on the limitations of existing methods. A physiological silicone rubber abdominal aortic aneurysm (AAA) model for fixation studies was manufactured based on an idealized AAA geometry: the model had a 24-mm neck, a 50-mm aneurysm, 12-mm-diameter legs, a 60 degrees bifurcation angle, and 2-mm-thick walls. The models were authenticated in neck fixation experiments. The displacement force required to migrate stent-grafts in physiological pulsatile flow was tested dynamically in water at 37 degrees C. A commercially available longitudinally rigid stent-graft (AneuRx) and a homemade device with little longitudinal rigidity were studied in a number of different configurations to investigate the effect of neck fixation length and systolic pressure on displacement force. The AneuRx (6.95+/-0.49 to 8.52+/-0.5 N) performed significantly better than the homemade device (2.57+/-0.11 to 4.62+/-0.25 N) in pulsatile flow. The opposite was true in the neck fixation tests because the longitudinal stiffness of the AneuRx was not accounted for. Increasing pressure or decreasing fixation length compromised the fixation of the homemade device. This relationship was not as clear for the AneuRx because decreasing proximal fixation resulted in an increase in iliac fixation, which could assist fixation in this device. Assessing the migration resistance of stent-grafts based solely on proximal fixation discriminates against devices that are longitudinally stiff. Current in vivo models may give inaccurate displacement forces due to the high degree of oversizing in these studies. A novel in vitro approach, accounting for longitudinal rigidity and realistic graft oversizing, was developed to determine the resistance of aortic stent-grafts to migration in the period immediately after device implantation.

  12. Persistent type II endoleak after EVAR: the predictive value of the AAA thrombus volume.

    PubMed

    Gallitto, Enrico; Gargiulo, Mauro; Mascoli, Chiara; Freyrie, Antonio; DE Matteis, Massimo; Serra, Carla; Bianchini Massoni, Claudio; Faggioli, Gianluca; Stella, Andrea

    2018-02-01

    Persistent type II endoleaks (ELIIp, ≥6 months) after an endovascular aneurysm repair (EVAR) can be associated with adverse outcomes. The aims of this study are the evaluation of the incidence of ELIIp, their preoperative morphological predictive features (PMF) and the post-EVAR abdominal aortic aneurysm (AAA) evolution in the presence of ELIIp. Patients underwent EVAR between 2008 and 2010 were prospectively collected. Cases with ELIIp (group A: AG) were identified. A control group without ELIIp (group B: BG), homogeneous for clinical characteristics, follow-up timing and methods (CTA and/or CEUS at 6.12 months and yearly thereafter) was retrospectively selected. The PMF evaluated by computed-tomography-angiography (CTA) were: AAA-diameter, number and diameter of AAA efferent patent vessels (EPV), AAA-total volume (TV), AAA-thrombus volume (THV) and TV/THV rate (%VR). Volumes were calculated by the dedicated vessels analysis software. AG and BG were compared. The primary endpoint was to evaluate the incidence of ELIIp. Secondary endpoints were to analyze the relation between PMF and ELIIp and to assess the post-EVAR AAA-evolution in the presence of ELIIp. Between 2008 and 2010, 200 patients underwent EVAR to treat AAA electively. An ELIIp was detected in 35cases (17.5%) (AG). Twenty-seven patients (13.5%) were included in BG. An overall of 62 patients (GA+GB) were analyzed. The mean pre-operative AAA diameter and EPV were 58±11.6 mm and 5.5±1.8 mm, respectively. The mean TV and THV were 187±111.5 cc and 82±75 cc, respectively. The median %VR was 42.3%. ELIIp was correlated to EPV≥6 (χ2, p=.015) and %VR <40% (logistic regression, P=0.032). The mean follow-up was 22±9 months. Seven (20%) ELIIp spontaneously sealed and 6 (17%) required reinterventions (2 conversions to OR). There were not PMF associated to ELIIp evolution and AAA growth post-EVAR. ELIIp is a not rare complication and it could require re-interventions. Our data suggest that VEP≥6 or %VT<40

  13. Adipocytes and abdominal aortic aneurysm: Putative potential role of adipocytes in the process of AAA development.

    PubMed

    Kugo, Hirona; Moriyama, Tatsuya; Zaima, Nobuhiro

    2018-01-15

    Background Adipose tissue plays a role in the storage of excess energy as triglycerides (TGs). Excess fat accumulation causes various metabolic and cardiovascular diseases. It has been reported that ectopic fat deposition and excess TG accumulation in non-adipose tissue might be important predictors of cardiometabolic and vascular risk. For example, ectopic fat in perivascular tissue promotes atherosclerotic plaque formation in the arterial wall. Objective Recently, it has been reported that ectopic fat (adipocyte) in the vascular wall of an abdominal aortic aneurysm (AAA) is present in both human and experimental animal models. The pathological significance of adipocytes in the AAA wall has not been fully understood. In this review, we summarized the functions of adipocytes and discussed potential new drugs that target vascular adipocytes for AAA treatment. Result Previous studies suggest that adipocytes in vascular wall play an important role in the development of AAA. Conclusion Adipocytes in the vascular wall could be novel targets for the development of AAA therapeutic drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  14. Soft tissue graft interference fit fixation: observations on graft insertion site healing and tunnel remodeling 2 years after ACL reconstruction in sheep.

    PubMed

    Hunt, Patrick; Rehm, Oliver; Weiler, Andreas

    2006-12-01

    Using soft tissue grafts for anterior cruciate ligament (ACL) reconstruction, insertion site healing plays a crucial role in the long-term fate of the graft. It has been shown in an experimental animal study that using a soft tissue graft and anatomic graft fixation, a direct ligamentous insertion alike the native ACL developed 24 weeks postoperatively. Yet there are no reports on the long-term insertion site healing of anatomically fixed soft tissue grafts. The objective of this study was to evaluate graft insertion site healing, the intra-tunnel fate of the graft and its osseous replacement 2 years after ACL reconstruction in sheep. The left ACLs of six sheep were replaced by an autologous flexor tendon split graft and anatomically fixed with biodegradable poly-(D, L-lactide) interference screws. Animals received polychromic sequential labeling at different points in time to determine bone apposition per period. For evaluation of the insertion site healing and intra-tunnel changes, MRI scans were taken in vivo. Following sacrifice, radiographic imaging, conventional histology and fluorescence microscopy was undertaken. Most of the specimens showed a wide direct ligamentous insertion. It showed patterns alike the direct ligament insertion seen in intact ACLs. The intra-tunnel part of the graft had completely lost its tendon-like structure and in two cases, it was separated from the graft insertion by a thick bony layer. The biodegradable interference screw was fully degraded in all specimens. Ossification of the former drill tunnels was intense, showing only partial-length tunnel remnants in one femoral and three tibial specimens. As the graft heals to the joint surface and the aperture site is closed with soft tissue, mechanical stress of the intra-tunnel part of the graft is eliminated and the bone tunnel is protected from synovial fluid, resulting in osseous bridging of the tunnel aperture site, accelerated intra-tunnel graft resorption and its osseous

  15. Soft tissue grafting to improve implant esthetics

    PubMed Central

    Kassab, Moawia M

    2010-01-01

    Dental implants are becoming the treatment of choice to replace missing teeth, especially if the adjacent teeth are free of restorations. When minimal bone width is present, implant placement becomes a challenge and often resulting in recession and dehiscence around the implant that leads to subsequent gingival recession. To correct such defect, the author turned to soft tissue autografting and allografting to correct a buccal dehiscence around tooth #24 after a malpositioned implant placed by a different surgeon. A 25-year-old woman presented with the chief complaint of gingival recession and exposure of implant threads around tooth #24. The patient received three soft tissue grafting procedures to augment the gingival tissue. The first surgery included a connective tissue graft to increase the width of the keratinized gingival tissue. The second surgery included the use of autografting (connective tissue graft) to coronally position the soft tissue and achieve implant coverage. The third and final surgery included the use of allografting material Alloderm to increase and mask the implant from showing through the gingiva. Healing period was uneventful for the patient. After three surgical procedures, it appears that soft tissue grafting has increased the width and height of the gingiva surrounding the implant. The accomplished thickness of gingival tissue appeared to mask the showing of implant threads through the gingival tissue and allowed for achieving the desired esthetic that the patient desired. The aim of the study is to present a clinical case with soft tissue grafting procedures. PMID:23662087

  16. Roles of conserved arginines in ATP-binding domains of AAA+ chaperone ClpB from Thermus thermophilus.

    PubMed

    Yamasaki, Takashi; Nakazaki, Yosuke; Yoshida, Masasuke; Watanabe, Yo-hei

    2011-07-01

    ClpB, a member of the expanded superfamily of ATPases associated with diverse cellular activities (AAA+), forms a ring-shaped hexamer and cooperates with the DnaK chaperone system to reactivate aggregated proteins in an ATP-dependent manner. The ClpB protomer consists of an N-terminal domain, an AAA+ module (AAA-1), a middle domain, and a second AAA+ module (AAA-2). Each AAA+ module contains highly conserved WalkerA and WalkerB motifs, and two arginines (AAA-1) or one arginine (AAA-2). Here, we investigated the roles of these arginines (Arg322, Arg323, and Arg747) of ClpB from Thermus thermophilus in the ATPase cycle and chaperone function by alanine substitution. These mutations did not affect nucleotide binding, but did inhibit the hydrolysis of the bound ATP and slow the threading of the denatured protein through the central pore of the T. thermophilus ClpB ring, which severely impaired the chaperone functions. Previously, it was demonstrated that ATP binding to the AAA-1 module induced motion of the middle domain and stabilized the ClpB hexamer. However, the arginine mutations of the AAA-1 module destabilized the ClpB hexamer, even though ATP-induced motion of the middle domain was not affected. These results indicated that the three arginines are crucial for ATP hydrolysis and chaperone activity, but not for ATP binding. In addition, the two arginines in AAA-1 and the ATP-induced motion of the middle domain independently contribute to the stabilization of the hexamer. © 2011 The Authors Journal compilation © 2011 FEBS.

  17. Shoulder replacement - discharge

    MedlinePlus

    Total shoulder arthroplasty - discharge; Endoprosthetic shoulder replacement - discharge; Partial shoulder replacement - discharge; Partial shoulder arthroplasty - discharge; Replacement - shoulder - discharge; Arthroplasty - shoulder - ...

  18. Hepatorenal revascularization enables EVAR repair on a patient with AAA and an ectopic right renal artery.

    PubMed

    Lazaris, A M; Moulakakis, K; Mantas, G; Poulou, K; Alexiou, E; Vasdekis, S; Geroulakos, G

    2018-06-07

    The last thirty years the endovascular repair (EVAR) has become the standard method of treatment of abdominal aortic aneurysms (AAA). Nevertheless, the method has limitations based mainly on the anatomic characteristics of the specific aneurysm. In these cases a combination of endovascular and open techniques can be used. We describe a case of a patient with an infrarenal AAA and an ectopic right renal artery emerging from within the aneurysm sac. The patient was treated with a combination of endovascular and open techniques. In particular, he underwent a hepatorenal revascularization followed by a standard EVAR procedure, with a successful final outcome. For the treatment of AAA disease, the combination of open and endovascular procedures can overcome difficulties where a standard EVAR cannot be an option. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. The AAA protein spastin possesses two levels of basal ATPase activity.

    PubMed

    Fan, Xiangyu; Lin, Zhijie; Fan, Guanghui; Lu, Jing; Hou, Yongfei; Habai, Gulijiazi; Sun, Linyue; Yu, Pengpeng; Shen, Yuequan; Wen, Maorong; Wang, Chunguang

    2018-05-01

    The AAA ATPase spastin is a microtubule-severing enzyme that plays important roles in various cellular events including axon regeneration. Herein, we found that the basal ATPase activity of spastin is negatively regulated by spastin concentration. By determining a spastin crystal structure, we demonstrate the necessity of intersubunit interactions between spastin AAA domains. Neutralization of the positive charges in the microtubule-binding domain (MTBD) of spastin dramatically decreases the ATPase activity at low concentration, although the ATP-hydrolyzing potential is not affected. These results demonstrate that, in addition to the AAA domain, the MTBD region of spastin is also involved in regulating ATPase activity, making interactions between spastin protomers more complicated than expected. © 2018 Federation of European Biochemical Societies.

  20. Role of mitochondrial processing peptidase and AAA proteases in processing of the yeast acetohydroxyacid synthase precursor.

    PubMed

    Dasari, Suvarna; Kölling, Ralf

    2016-07-01

    We studied presequence processing of the mitochondrial-matrix targeted acetohydroxyacid synthase (Ilv2). C-terminal 3HA-tagging altered the cleavage pattern from a single step to sequential two-step cleavage, giving rise to two Ilv2-3HA forms (A and B). Both cleavage events were dependent on the mitochondrial processing peptidase (MPP). We present evidence for the involvement of three AAA ATPases, m- and i-AAA proteases, and Mcx1, in Ilv2-3HA processing. Both, precursor to A-form and A-form to B-form cleavage were strongly affected in a ∆yme1 mutant. These defects could be suppressed by overexpression of MPP, suggesting that MPP activity is limiting in the ∆yme1 mutant. Our data suggest that for some substrates AAA ATPases could play an active role in the translocation of matrix-targeted proteins.

  1. Calcar bone graft

    SciTech Connect

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

    1986-01-01

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

  2. Increased AAA-TOB3 correlates with lymph node metastasis and advanced stage of lung adenocarcinoma.

    PubMed

    Liu, Yanfeng; Bu, Lina; Li, Wei; Wu, Wei; Wang, Shengyu; Diao, Xin; Zhou, Jing; Chen, Guoan; Yang, Shuanying

    2017-07-24

    This study was to investigate the differential mitochondrial protein expressions in human lung adenocarcinoma and provide preliminary data for further exploration of the carcinogenic mechanism. Total proteins of A549 and 16HBE mitochondria were extracted through 2D polyacrylamide gel electrophoresis (2-DE). The differential mitochondria proteins were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and were further confirmed by Western blot, immunoelectron microscopy and immunohistochemistry (IHC) in A549 cells as well as lung adenocarcinoma tissues. A total of 41 differentially expressed protein spots were found in A549 mitochondria. Of them, 15 proteins were highly expressed and 26 proteins were lowly expressed in the mitochondria of A549 (by more than 1.5 times). Among the 15 more highly expressed proteins, AAA-TOB3 (by more than 3 times) was highly expressed in the mitochondria of A549 compared with the 16HBE, by LC-MS/MS identification. High electron density and clear circular colloidal gold-marked AAA-TOB3 particles were observed in the A549 cells via immunoelectron microscopy. Besides, AAA-TOB3 was confirmed to be elevated in lung adenocarcinoma by Western blot and IHC. Moreover, increased AAA-TOB3 correlated with lymph node metastasis and advanced stage of lung adenocarcinoma (p<0.05). AAA-TOB3 was highly expressed in lung adenocarcinoma, and the up-regulation of AAA-TOB3 correlated with lymph node metastasis and advanced stage of lung adenocarcinoma, which suggested that it could serve as a potential molecular marker for lung adenocarcinoma.

  3. Dosimetric comparison of Acuros XB, AAA, and XVMC in stereotactic body radiotherapy for lung cancer.

    PubMed

    Tsuruta, Yusuke; Nakata, Manabu; Nakamura, Mitsuhiro; Matsuo, Yukinori; Higashimura, Kyoji; Monzen, Hajime; Mizowaki, Takashi; Hiraoka, Masahiro

    2014-08-01

    To compare the dosimetric performance of Acuros XB (AXB), anisotropic analytical algorithm (AAA), and x-ray voxel Monte Carlo (XVMC) in heterogeneous phantoms and lung stereotactic body radiotherapy (SBRT) plans. Water- and lung-equivalent phantoms were combined to evaluate the percentage depth dose and dose profile. The radiation treatment machine Novalis (BrainLab AG, Feldkirchen, Germany) with an x-ray beam energy of 6 MV was used to calculate the doses in the composite phantom at a source-to-surface distance of 100 cm with a gantry angle of 0°. Subsequently, the clinical lung SBRT plans for the 26 consecutive patients were transferred from the iPlan (ver. 4.1; BrainLab AG) to the Eclipse treatment planning systems (ver. 11.0.3; Varian Medical Systems, Palo Alto, CA). The doses were then recalculated with AXB and AAA while maintaining the XVMC-calculated monitor units and beam arrangement. Then the dose-volumetric data obtained using the three different radiation dose calculation algorithms were compared. The results from AXB and XVMC agreed with measurements within ± 3.0% for the lung-equivalent phantom with a 6 × 6 cm(2) field size, whereas AAA values were higher than measurements in the heterogeneous zone and near the boundary, with the greatest difference being 4.1%. AXB and XVMC agreed well with measurements in terms of the profile shape at the boundary of the heterogeneous zone. For the lung SBRT plans, AXB yielded lower values than XVMC in terms of the maximum doses of ITV and PTV; however, the differences were within ± 3.0%. In addition to the dose-volumetric data, the dose distribution analysis showed that AXB yielded dose distribution calculations that were closer to those with XVMC than did AAA. Means ± standard deviation of the computation time was 221.6 ± 53.1 s (range, 124-358 s), 66.1 ± 16.0 s (range, 42-94 s), and 6.7 ± 1.1 s (range, 5-9 s) for XVMC, AXB, and AAA, respectively. In the phantom evaluations, AXB and XVMC agreed better with

  4. Statins: the holy grail of Abdominal Aortic Aneurysm (AAA) growth attenuation? A systematic review of the literature.

    PubMed

    Dunne, Jonathan A; Bailey, Marc A; Griffin, Kathryn J; Sohrabi, Soroush; Coughlin, Patrick A; Scott, D Julian A

    2014-01-01

    In the era of Abdominal Aortic Aneurysm (AAA) screening, pharmacotherapies to attenuate AAA growth are sought. HMG Co-A reductase inhibitors (statins) have pleiotropic actions independent of their lipid lowering effects and have been suggested as potential treatment for small AAAs. We systematically review the clinical evidence for this effect. Medline, EMBASE and the Cochrane Central Register of Controlled Trials (1950-2011) were searched for studies reporting data on the role of statin therapy on AAA growth rate. No language restrictions were placed on the search. References of retrieved articles and pertinent journals were hand searched. Included studies were reviewed by 2 independent observers. The search retrieved 164 papers, 100 were irrelevant based on their title, 47 were reviews and 1 was a letter. 8 studies were excluded based on review of their abstract leaving 8 for inclusion in the study. Eight observational clinical studies with a total of 4,466 patients were reviewed. Four studies demonstrated reduced AAA expansion in statin users while 4 studies failed to demonstrate this effect. The method of determining AAA growth rates varied significantly between the studies and the ability of many studies to control for misclassification bias was poor. The claim that statins attenuate AAA growth remains questionable. Further prospective studies with stringent identification and verification of statin usage and a standardised method of estimating AAA growth rates are required. Statin type and dose also merit consideration.

  5. Hip joint replacement

    MedlinePlus

    ... Total hip replacement; Hip hemiarthroplasty; Arthritis - hip replacement; Osteoarthritis - hip replacement ... total hip replacement surgery in patients with hip osteoarthritis: a long-term follow-up of a randomised ...

  6. Limb reconstruction with vascularized fibular grafts after bone tumor resection.

    PubMed

    Brown, K L

    1991-01-01

    Limb-salvage operations are being used with increasing frequency for patients with malignant bone tumors. For children, when a biologic reconstruction is desired, the choice is often between conventional and vascularized fibular grafts. An experimental study was performed in dogs to compare the two types of fibular grafts for bridging segmental defects in the radius and ulna. Twenty-six adult dogs were divided into two groups and studied at intervals of two, three, four, six, and 12 months after transplantation. The conventional grafts healed by creeping substitution i.e., they were first partially resorbed before new bone was laid down. In contrast, the vascularized fibulae maintained their normal structure and hypertrophied by subperiosteal new bone formation. The conventional fibulae eventually hypertrophied but much later than the vascularized grafts. The vascularized grafts were stronger at four and six months. Between six and 12 months, both grafts remodeled to resemble the size and shape of the forearm bones they were replacing. These experimental results have influenced the treatment of patients. Vascularized fibular grafts are ideal for diaphyseal defects greater than 10 cm long, especially in very young children, a poorly vascularized bed, or when bone healing is delayed by chemotherapeutic agents. To maximize hypertrophy, an external fixator is used to immobilize the graft rather than a plate, which acts as a stress shield.

  7. Selective Intra-procedural AAA sac Embolization During EVAR Reduces the Rate of Type II Endoleak.

    PubMed

    Mascoli, C; Freyrie, A; Gargiulo, M; Gallitto, E; Pini, R; Faggioli, G; Serra, C; De Molo, C; Stella, A

    2016-05-01

    The pre-treatment presence of at least six efferent patent vessels (EPV) from the AAA sac and/or AAA thrombus volume ratio (VR%) <40% are considered to be positive predictive factors for persistent type II endoleak (ELIIp). The aim of the present study was to evaluate the effectiveness of sac embolization during EVAR in patients with pre-operative morphological risk factors (p-MRF) for ELIIp. Patients undergoing EVAR and intra-procedural AAA sac embolization (Group A, 2012-2013) were retrospectively selected and compared with a control group of patients with the same p-MRF, who underwent EVAR without intra-procedural sac embolization (Group B, 2008-2010). The presence of ELIIp was evaluated by duplex ultrasound at 0 and 6 months, and by contrast enhanced ultrasound at 12 months. The association between AAA diameter, age, COPD, smoking, anticoagulant therapy, and AAA sac embolization with ELIIp was evaluated using multiple logistic regression. The primary endpoint was the effectiveness of the intra-procedural AAA sac embolization for ELIIp prevention. Secondary endpoints were AAA sac evolution and freedom from ELIIp and embolization related re-interventions at 6-12 months. Seventy patients were analyzed: 26 Group A and 44 Group B; the groups were homogeneous for clinical/morphological characteristics. In Group A the median number of coils positioned in AAA sac was 4.1 (IQR 1). There were no complications related to the embolization procedures. A significantly lower number of ELIIp was detected in Group A than in Group B (8/26 vs. 33/44, respectively, p < .001) at discharge, and this was confirmed at 6-12 months (7/26 vs. 30/44 respectively, p = .001, and 5/25 vs. 32/44, respectively, p < .001). On multivariate analysis, intra-procedural AAA sac embolization was the only factor independently associated with freedom from ELIIp at 6 (OR 0.196, 95% CI 0.06-0.63; p = .007) and 12 months (OR 0.098, 95% CI 0.02-0.35; p < .001). No differences in median AAA sac

  8. Grafting in Arabidopsis.

    PubMed

    Bainbridge, Katherine; Bennett, Tom; Crisp, Peter; Leyser, Ottoline; Turnbull, Colin

    2014-01-01

    Grafting provides a simple way to generate chimeric plants with regions of different genotypes and thus to assess the cell autonomy of gene action. The technique of grafting has been widely used in other species, but in Arabidopsis, its small size makes the process rather more demanding. However, there are now several well-established grafting procedures available, which we described here, and their use has already contributed greatly to understanding of such processes as shoot branching control, flowering, disease resistance, and systemic silencing.

  9. Primary nerve grafting: A study of revascularization.

    PubMed

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

    2003-01-01

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

  10. Stan Bull, Long-Time NREL Leader, Named AAAS Fellow | News | NREL

    Science.gov Websites

    , Named AAAS Fellow January 11, 2011 Stanley R. Bull, former associate director for Science and Technology emeritus researcher. He was cited for "distinguished leadership in creating new programs, development partner with existing energy companies, including the fossil-fuel industry, and to "provide our

  11. Structure and Function of p97 and Pex1/6 Type II AAA+ Complexes.

    PubMed

    Saffert, Paul; Enenkel, Cordula; Wendler, Petra

    2017-01-01

    Protein complexes of the Type II AAA+ (ATPases associated with diverse cellular activities) family are typically hexamers of 80-150 kDa protomers that harbor two AAA+ ATPase domains. They form double ring assemblies flanked by associated domains, which can be N-terminal, intercalated or C-terminal to the ATPase domains. Most prominent members of this family include NSF (N-ethyl-maleimide sensitive factor), p97/VCP (valosin-containing protein), the Pex1/Pex6 complex and Hsp104 in eukaryotes and ClpB in bacteria. Tremendous efforts have been undertaken to understand the conformational dynamics of protein remodeling type II AAA+ complexes. A uniform mode of action has not been derived from these works. This review focuses on p97/VCP and the Pex1/6 complex, which both structurally remodel ubiquitinated substrate proteins. P97/VCP plays a role in many processes, including ER- associated protein degradation, and the Pex1/Pex6 complex dislocates and recycles the transport receptor Pex5 from the peroxisomal membrane during peroxisomal protein import. We give an introduction into existing knowledge about the biochemical and cellular activities of the complexes before discussing structural information. We particularly emphasize recent electron microscopy structures of the two AAA+ complexes and summarize their structural differences.

  12. Effects of doping and bias voltage on the screening in AAA-stacked trilayer graphene

    NASA Astrophysics Data System (ADS)

    Mohammadi, Yawar; Moradian, Rostam; Shirzadi Tabar, Farzad

    2014-09-01

    We calculate the static polarization of AAA-stacked trilayer graphene (TLG) and study its screening properties within the random phase approximation (RPA) in all undoped, doped and biased regimes. We find that the static polarization of undoped AAA-stacked TLG is a combination of the doped and undoped single-layer graphene static polarization. This leads to an enhancement of the dielectric background constant along a Thomas-Fermi screening with the Thomas-Fermi wave vector which is independent of carrier concentrations and a 1/r3 power law decay for the long-distance behavior of the screened Coulomb potential. We show that effects of a bias voltage can be taken into account by a renormalization of the interlayer hopping energy to a new bias-voltage-dependent value, indicating screening properties of AAA-stacked TLG can be tuned electrically. We also find that screening properties of doped AAA-stacked TLG, when μ exceeds √{2}γ, are similar to that of doped SLG only depending on doping. While for μ<√{2}γ, its screening properties are combination of SLG and AA-stacked bilayer graphene screening properties and they are determined by doping and the interlayer hopping energy.

  13. Improved Resident Adherence to AAA Screening Guidelines via an Electronic Reminder.

    PubMed

    Sypert, David; Van Dyke, Kenneth; Dhillon, Namrata; Elliott, John O; Jordan, Kim

    The 2014 United States Preventive Services Task Force systematic review found abdominal aortic aneurysm (AAA) screening decreased related mortality by close to half. Despite the simplicity of screening, research suggests poor adherence to the recommended AAA screening guidelines. Using the quality improvement plan-study-do-act cycle, we retrospectively established poor adherence to AAA screening and poor documentation of smoking history in our resident clinic. An electronic reminder was prospectively implemented into our electronic medical record (EMR) with the goal of improving screening rates. After 1 year, a retrospective chart review was conducted. Comparisons of the pre- and post-electronic reminder intervention data were made using chi-square tests and odds ratios (OR). The purposeful AAA screening rate improved 27.8% during the intervention, 40.3% (95% confidence interval [CI]: 28.6-52.0%) versus 12.5% (95% CI: 3.1-21.9%), p = .002, suggesting patients were more likely to be screened as a result of the electronic reminder, OR = 4.73 (95% CI: 1.77-12.65). This improvement translates to a large effect size, Cohen's d = 0.86 (95% CI: 0.31-1.40). Electronic reminders are a simple EMR addition that can provide evidence-based education while improving adherence rates with preventive health screening measures.

  14. Fan filter cleaning on the CHeCS AAA in the US Lab

    NASA Image and Video Library

    2009-05-05

    ISS019-E-013710 (5 May 2009) --- Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata, Expedition 19/20 flight engineer, cleans a fan filter on the Crew Health Care System Avionics Air Assembly (CHeCS AAA) in the Destiny laboratory of the International Space Station.

  15. National dosimetric audit network finds discrepancies in AAA lung inhomogeneity corrections.

    PubMed

    Dunn, Leon; Lehmann, Joerg; Lye, Jessica; Kenny, John; Kron, Tomas; Alves, Andrew; Cole, Andrew; Zifodya, Jackson; Williams, Ivan

    2015-07-01

    This work presents the Australian Clinical Dosimetry Service's (ACDS) findings of an investigation of systematic discrepancies between treatment planning system (TPS) calculated and measured audit doses. Specifically, a comparison between the Anisotropic Analytic Algorithm (AAA) and other common dose-calculation algorithms in regions downstream (≥2cm) from low-density material in anthropomorphic and slab phantom geometries is presented. Two measurement setups involving rectilinear slab-phantoms (ACDS Level II audit) and anthropomorphic geometries (ACDS Level III audit) were used in conjunction with ion chamber (planar 2D array and Farmer-type) measurements. Measured doses were compared to calculated doses for a variety of cases, with and without the presence of inhomogeneities and beam-modifiers in 71 audits. Results demonstrate a systematic AAA underdose with an average discrepancy of 2.9 ± 1.2% when the AAA algorithm is implemented in regions distal from lung-tissue interfaces, when lateral beams are used with anthropomorphic phantoms. This systemic discrepancy was found for all Level III audits of facilities using the AAA algorithm. This discrepancy is not seen when identical measurements are compared for other common dose-calculation algorithms (average discrepancy -0.4 ± 1.7%), including the Acuros XB algorithm also available with the Eclipse TPS. For slab phantom geometries (Level II audits), with similar measurement points downstream from inhomogeneities this discrepancy is also not seen. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  16. SOFIA Technology: The NASA Airborne Astronomy Ambassador (AAA) Experience and Online Resources

    NASA Astrophysics Data System (ADS)

    Clark, C.; Harman, P. K.; Backman, D. E.

    2016-12-01

    SOFIA, an 80/20 partnership of NASA and the German Aerospace Center (DLR), consists of a modified Boeing 747SP carrying a reflecting telescope with an effective diameter of 2.5 meters. SOFIA is the largest airborne observatory in the world, capable of observations impossible for even the largest and highest ground-based telescopes. The SOFIA Program Office is at NASA ARC, Moffett Field, CA; the aircraft is based in Palmdale, CA. During its planned 20-year lifetime, SOFIA will foster development of new scientific instrumentation and inspire the education of young scientists and engineers. Astrophysicists are awarded time on SOFIA to study many kinds of astronomical objects and phenomena. Among the most interesting are: Star birth, evolution, and death Formation of new planetary systems Chemistry of complex molecules in space Planet and exoplanet atmospheres Galactic gas & dust "ecosystems" Environments around supermassive black holes SOFIA currently has eight instruments, five US-made and three German. The instruments — cameras, spectrometers, and a photometer,— operate at near-, mid- and far-infrared wavelengths, each spectral range being best suited to studying particular celestial phenomena. NASA's Airborne Astronomy Ambassadors' (AAAs) experience includes a STEM immersion component. AAAs are onboard during two overnight SOFIA flights that provide insight into the acquisition of scientific data as well as the interfaces between the telescope, instrument, & aircraft. AAAs monitor system performance and view observation targets from their dedicated workstation during flights. Future opportunities for school district partnerships leading to selection of future AAA cohorts will be offered in 2018-19. AAAs may access public archive data via the SOFIA Data Cycle System (DCS) https://dcs.sofia.usra.edu/. Additional SOFIA science and other resources are available at: www.sofia.usra.edu, including lessons that use photovoltaic circuits, and other technology for the

  17. Asymmetric processing of a substrate protein in sequential allosteric cycles of AAA+ nanomachines

    NASA Astrophysics Data System (ADS)

    Kravats, Andrea N.; Tonddast-Navaei, Sam; Bucher, Ryan J.; Stan, George

    2013-09-01

    Essential protein quality control includes mechanisms of substrate protein (SP) unfolding and translocation performed by powerful ring-shaped AAA+ (ATPases associated with various cellular activities) nanomachines. These SP remodeling actions are effected by mechanical forces imparted by AAA+ loops that protrude into the central channel. Sequential intra-ring allosteric motions, which underlie repetitive SP-loop interactions, have been proposed to comprise clockwise (CW), counterclockwise (CCW), or random (R) conformational transitions of individual AAA+ subunits. To probe the effect of these allosteric mechanisms on unfoldase and translocase functions, we perform Langevin dynamics simulations of a coarse-grained model of an all-alpha SP processed by the single-ring ClpY ATPase or by the double-ring p97 ATPase. We find that, in all three allosteric mechanisms, the SP undergoes conformational transitions along a common set of pathways, which reveals that the active work provided by the ClpY machine involves single loop-SP interactions. Nevertheless, the rates and yields of SP unfolding and translocation are controlled by mechanism-dependent loop-SP binding events, as illustrated by faster timescales of SP processing in CW allostery compared with CCW and R allostery. The distinct efficacy of allosteric mechanisms is due to the asymmetric collaboration of adjacent subunits, which involves CW-biased structural motions of AAA+ loops and results in CW-compatible torque applied onto the SP. Additional simulations of mutant ClpY rings, which render a subset of subunits catalytically-defective or reduce their SP binding affinity, reveal that subunit-based conformational transitions play the major role in SP remodeling. Based on these results we predict that the minimally functional AAA+ ring includes three active subunits, only two of which are adjacent.

  18. A conserved inter-domain communication mechanism regulates the ATPase activity of the AAA-protein Drg1.

    PubMed

    Prattes, Michael; Loibl, Mathias; Zisser, Gertrude; Luschnig, Daniel; Kappel, Lisa; Rössler, Ingrid; Grassegger, Manuela; Hromic, Altijana; Krieger, Elmar; Gruber, Karl; Pertschy, Brigitte; Bergler, Helmut

    2017-03-17

    AAA-ATPases fulfil essential roles in different cellular pathways and often act in form of hexameric complexes. Interaction with pathway-specific substrate and adaptor proteins recruits them to their targets and modulates their catalytic activity. This substrate dependent regulation of ATP hydrolysis in the AAA-domains is mediated by a non-catalytic N-terminal domain. The exact mechanisms that transmit the signal from the N-domain and coordinate the individual AAA-domains in the hexameric complex are still the topic of intensive research. Here, we present the characterization of a novel mutant variant of the eukaryotic AAA-ATPase Drg1 that shows dysregulation of ATPase activity and altered interaction with Rlp24, its substrate in ribosome biogenesis. This defective regulation is the consequence of amino acid exchanges at the interface between the regulatory N-domain and the adjacent D1 AAA-domain. The effects caused by these mutations strongly resemble those of pathological mutations of the AAA-ATPase p97 which cause the hereditary proteinopathy IBMPFD (inclusion body myopathy associated with Paget's disease of the bone and frontotemporal dementia). Our results therefore suggest well conserved mechanisms of regulation between structurally, but not functionally related members of the AAA-family.

  19. SU-F-T-413: Calculation Accuracy of AAA and Acuros Using Cerrobend Blocks for TBI at 400cm

    SciTech Connect

    Lamichhane, N; Studenski, M

    2016-06-15

    Purpose: It is essential to assess the lung dose during TBI to reduce toxicity. Here we characterize the accuracy of the AAA and Acuros algorithms when using cerrobend lung shielding blocks at an extended distance for TBI. Methods: We positioned a 30×30×30 cm3 solid water slab phantom at 400 cm SSD and measured PDDs (Exradin A12 and PTW parallel plate ion chambers). A 2 cm thick, 10×10 cm2 cerrobend block was hung 2 cm in front of the phantom. This geometry was reproduced in the planning system for both AAA and Acuros. In AAA, the mass density of the cerrobendmore » block was forced to 9.38 g/cm3 and in Acuros it was forced to 8.0 g/cm3 (limited to selecting stainless steel). Three different relative electron densities (RED) were tested for each algorithm; 4.97, 6.97, and 8.97. Results: PDDs from both Acuros and AAA underestimated the delivered dose. AAA calculated that depth dose was higher for RED of 4.97 as compared to 6.97 and 8.97 but still lower than measured. There was no change in the percent depth dose with changing relative electron densities for Acuros. Conclusion: Care should be taken before using AAA or Acuros with cerrobend blocks as the planning system underestimates dose. Acuros limits the ability to modify RED when compared to AAA.« less

  20. Cruciate ligament replacement using a meniscus. An experimental study.

    PubMed

    Mitsou, A; Vallianatos, P; Piskopakis, N; Nicolaou, P

    1988-11-01

    In 30 rabbits, the medial meniscus was used to replace the anterior or posterior cruciate ligament. The changes that took place were followed in histological sections, obtained both from the area of insertion into bone and from the intra-articular part of the graft. There was a gradual differentiation to chondroid tissue, with subsequent calcific deposition and no appearance of normal ligamentous tissue. The strength of the graft after 52 weeks was only one-quarter of that of the normal ligament. Our results do not justify the use of the meniscus to replace a torn cruciate ligament.

  1. Bone grafts utilized in dentistry: an analysis of patients' preferences.

    PubMed

    Fernández, Ramón Fuentes; Bucchi, Cristina; Navarro, Pablo; Beltrán, Víctor; Borie, Eduardo

    2015-10-20

    Many procedures currently require the use of bone grafts to replace or recover bone volume that has been resorbed. However, the patient's opinion and preferences must be taken into account before implementing any treatment. Researchers have focused primarily on assessing the effectiveness of bone grafts rather than on patients' perceptions. Thus, the aim of this study was to explore patients' opinions regarding the different types of bone grafts used in dental treatments. One hundred patients were randomly chosen participated in the study. A standardized survey of 10 questions was used to investigate their opinions regarding the different types of bone grafts used in dental treatments. Descriptive statistics were calculated for the different variables, and absolute frequencies and percentages were used as summary measures. A value of p <0.05 was selected as the threshold for statistical significance. The highest rate of refusal was observed for allografts and xenografts. The grafts with the lowest rates of refusal were autologous grafts (3 %) and alloplastics (2 %). No significant differences were found between the various types of bone grafts in the sociodemographic variables or the refusal/acceptance variable. Similarly, no significant relations were observed between a specific religious affiliation and the acceptance/refusal rates of the various types of graft. Allografts and xenografts elicited the highest refusal rates among the surveyed patients, and autologous bone and alloplastics were the most accepted bone grafts. Moreover, no differences were found in the sociodemographic variables or religious affiliations in terms of the acceptance/refusal rates of the different bone grafts.

  2. A 5-year evaluation using the talent endovascular graft for endovascular aneurysm repair in short aortic necks.

    PubMed

    Jim, Jeffrey; Sanchez, Luis A; Rubin, Brian G; Criado, Frank J; Fajardo, Andres; Geraghty, Patrick J; Sicard, Gregorio A

    2010-10-01

    Although endovascular aneurysm repair has been shown to be an effective way to treat abdominal aortic aneurysm (AAA), certain anatomic characteristics such as a short aortic neck, limit its applicability. Initially, commercially available devices were approved only for the treatment of AAA with an aortic neck length ≥ 15 mm. The purpose of this study was to evaluate the outcomes of the recently approved Talent endograft for AAAs with a short aortic neck length (10-15 mm). Data were obtained from the prospective, nonrandomized, multicenter Talent enhanced Low Profile Stent Graft System trial which enrolled patients between February 2002 and April 2003. A total of 154 patients with adequate preoperative imaging were identified for this study. Subgroup analyses were performed for AAA with 10-15 mm aortic neck and those with >15 mm neck. Safety and effectiveness endpoints were evaluated at 30 days, 1 year, and 5 years postprocedure. Patients treated with aortic neck lengths of 10-15 mm (n = 35) and those with >15 mm (n = 102) had similar age, gender, and risk factor profile. Both groups had similar preoperative aneurysm morphology in terms of maximum aneurysm size, degree of neck angulation, or proximal neck diameter. There were no statistically significant differences in freedom from major adverse events and mortality rates at 30 and 365 days. Similarly, there was no difference in the effectiveness endpoints at 12 months. At 5 years, there was no difference in migration rate, endoleaks, or change in aneurysm diameter from baseline. In addition, there is no difference in freedom from aneurysm-related mortality (94% vs. 99%). AAAs with short aortic necks (10-15 mm) and otherwise suitable anatomy for endovascular repair can be safely and effectively treated with the Talent endograft with excellent 1 and 5 year outcomes. Copyright © 2010. Published by Elsevier Inc.

  3. The versatile subepithelial connective tissue graft: a literature update.

    PubMed

    Karthikeyan, B V; Khanna, Divya; Chowdhary, Kamedh Yashawant; Prabhuji, M Lv

    2016-01-01

    Harmony between hard and soft tissue morphologies is essential for form, function, and a good esthetic outlook. Replacement grafts for correction of soft tissue defects around the teeth have become important to periodontal plastic and implant surgical procedures. Among a multitude of surgical techniques and graft materials reported in literature, the subepithelial connective tissue graft (SCTG) has gained wide popularity and acceptance. The purpose of this article is to acquaint clinicians with the current understanding of the versatile SCTG. Key factors associated with graft harvesting as well as applications, limitations, and complications of SCTGs are discussed. This connective tissue has shown excellent short- and long-term stability, is easily available, and is economical to use. The SCTG should be considered as an alternative in all periodontal reconstruction surgeries.

  4. Clinical implementation of AXB from AAA for breast: Plan quality and subvolume analysis.

    PubMed

    Guebert, Alexandra; Conroy, Leigh; Weppler, Sarah; Alghamdi, Majed; Conway, Jessica; Harper, Lindsay; Phan, Tien; Olivotto, Ivo A; Smith, Wendy L; Quirk, Sarah

    2018-05-01

    Two dose calculation algorithms are available in Varian Eclipse software: Anisotropic Analytical Algorithm (AAA) and Acuros External Beam (AXB). Many Varian Eclipse-based centers have access to AXB; however, a thorough understanding of how it will affect plan characteristics and, subsequently, clinical practice is necessary prior to implementation. We characterized the difference in breast plan quality between AXB and AAA for dissemination to clinicians during implementation. Locoregional irradiation plans were created with AAA for 30 breast cancer patients with a prescription dose of 50 Gy to the breast and 45 Gy to the regional node, in 25 fractions. The internal mammary chain (IMC CTV ) nodes were covered by 80% of the breast dose. AXB, both dose-to-water and dose-to-medium reporting, was used to recalculate plans while maintaining constant monitor units. Target coverage and organ-at-risk doses were compared between the two algorithms using dose-volume parameters. An analysis to assess location-specific changes was performed by dividing the breast into nine subvolumes in the superior-inferior and left-right directions. There were minimal differences found between the AXB and AAA calculated plans. The median difference between AXB and AAA for breast CTV V 95% , was <2.5%. For IMC CTV , the median differences V 95% , and V 80% were <5% and 0%, respectively; indicating IMC CTV coverage only decreased when marginally covered. Mean superficial dose increased by a median of 3.2 Gy. In the subvolume analysis, the medial subvolumes were "hotter" when recalculated with AXB and the lateral subvolumes "cooler" with AXB; however, all differences were within 2 Gy. We observed minimal difference in magnitude and spatial distribution of dose when comparing the two algorithms. The largest observable differences occurred in superficial dose regions. Therefore, clinical implementation of AXB from AAA for breast radiotherapy is not expected to result in changes in clinical

  5. Monobloc Reconstruction of Dome, Medial Crura, and Columella with Gamma-Shaped Costal Cartilage Graft

    PubMed Central

    Bilgili, Ahmet Mert; Güven, Erdem

    2017-01-01

    Summary: In severe nasal deformities, the original cartilages are removed, or they become unusable because of previous operations. Costal cartilage (CC) is one of the most important tools for the replacement of deficient nasal osteocartilaginous framework. In 4 secondary and 1 tertiary rhinoplasty cases with severe deformities of medial and lateral crura of the lower lateral cartilages, we have prepared a long strut graft from a CC and then split the graft tip 5–6 mm vertically into 2 equal halves to create a gamma (ϒ)-shaped strut graft. We have sutured the base of this graft to the nasal spine and/or the bases of the medial crural remnants. Then, we have prepared lateral crural grafts and secured the grafts over lateral crural remnants. Then we curved the split tip winglets of the ϒ-shaped strut graft to both sides and sutured them to lateral crural grafts in order to create a new dome. Splitting of the CC strut graft reduces the need for extensive suturing at the tip, obtains smoother contours and ensures graft economy, and provides an original and stable dome shape. The bending capacity of the CC is limited in middle-aged patients. Costal allografts from a young cadaver can be a good alternative. ϒ-shaped costal crural graft is useful for medial crural and domal monobloc reconstruction in secondary and tertiary cases. PMID:29632798

  6. Grafting Technique to Eliminate Rootstock Suckering of Grafted Tomatoes

    USDA-ARS?s Scientific Manuscript database

    Vegetable grafting has been proposed as a technique for avoiding disease problems in tomatoes in open field production. In this study we investigated the current use of grafting in an open field scenario and found a serious problem with the grafting techniques. In the Fall of 2007, commercially pr...

  7. Substituent effects in double-helical hydrogen-bonded AAA-DDD complexes.

    PubMed

    Wang, Hong-Bo; Mudraboyina, Bhanu P; Wisner, James A

    2012-01-27

    Two series of DDD and AAA hydrogen-bond arrays were synthesized that form triply-hydrogen-bonded double-helical complexes when combined in CDCl(3) solution. Derivatization of the DDD arrays with electron-withdrawing groups increases the complex association constants by up to a factor of 30 in those arrays examined. Derivatization of the AAA arrays with electron donating substituents reveals a similar magnitude effect on the complex stabilities. The effect of substitution on both types of arrays are modeled quite satisfactorily (R(2) > 0.96 in all cases) as free energy relationships with respect to the sums of their Hammett substituent constants. In all, the complex stabilities can be manipulated over more than three orders of magnitude (>20 kJ mol(-1)) using this type of modification. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. SFM-FDTD analysis of triangular-lattice AAA structure: Parametric study of the TEM mode

    NASA Astrophysics Data System (ADS)

    Hamidi, M.; Chemrouk, C.; Belkhir, A.; Kebci, Z.; Ndao, A.; Lamrous, O.; Baida, F. I.

    2014-05-01

    This theoretical work reports a parametric study of enhanced transmission through annular aperture array (AAA) structure arranged in a triangular lattice. The effect of the incidence angle in addition to the inner and outer radii values on the evolution of the transmission spectra is carried out. To this end, a 3D Finite-Difference Time-Domain code based on the Split Field Method (SFM) is used to calculate the spectral response of the structure for any angle of incidence. In order to work through an orthogonal unit cell which presents the advantage to reduce time and space of computation, special periodic boundary conditions are implemented. This study provides a new modeling of AAA structures useful for producing tunable ultra-compact devices.

  9. Structural Basis of ATP Hydrolysis and Intersubunit Signaling in the AAA+ ATPase p97.

    PubMed

    Hänzelmann, Petra; Schindelin, Hermann

    2016-01-05

    p97 belongs to the superfamily of AAA+ ATPases and is characterized by a tandem AAA module, an N-terminal domain involved in substrate and cofactor interactions, and a functionally important unstructured C-terminal tail. The ATPase activity is controlled by an intradomain communication within the same protomer and an interdomain communication between neighboring protomers. Here, we present for the first time crystal structures in which the physiologically relevant p97 hexamer constitutes the content of the asymmetric unit, namely in the apo state without nucleotide in either the D1 or D2 module and in the pre-activated state with ATPγS bound to both modules. The structures provide new mechanistic insights into the interdomain communication mediated by conformational changes of the C terminus as well as an intersubunit signaling network, which couples the nucleotide state to the conformation of the central putative substrate binding pore. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Coordinated gripping of substrate by subunits of a AAA+ proteolytic machine

    PubMed Central

    Iosefson, Ohad; Nager, Andrew R.; Baker, Tania A.; Sauer, Robert T.

    2014-01-01

    Hexameric AAA+ unfoldases of ATP-dependent proteases and protein-remodeling machines use conserved loops that line the axial pore to apply force to substrates during the mechanical processes of protein unfolding and translocation. Whether loops from multiple subunits act independently or coordinately in these processes is a critical aspect of mechanism but is currently unknown for any AAA+ machine. By studying covalently linked hexamers of the E. coli ClpX unfoldase bearing different numbers and configurations of wild-type and mutant pore loops, we show that loops function synergistically, with the number of wild-type loops required for efficient degradation depending upon the stability of the protein substrate. Our results support a mechanism in which a power stroke initiated in one subunit of the ClpX hexamer results in the concurrent movement of all six pore loops, which coordinately grip and apply force to the substrate. PMID:25599533

  11. Aortic operation after previous coronary artery bypass grafting: management of patent grafts for myocardial protection.

    PubMed

    Nakajima, Masato; Tsuchiya, Koji; Fukuda, Shoji; Morimoto, Hironobu; Mitsumori, Yoshitaka; Kato, Kaori

    2006-04-01

    Aortic surgery for progressive aortic valve disease or aortic aneurysm after previous coronary artery bypass grafting (CABG) is a challenging procedure. We report the outcome of aortic reoperation after previous CABG and evaluate our management of patent grafts and our methods for obtaining myocardial protection. From February 2001 to July 2003, 6 patients with progressive aortic valve disease and aneurysm of the thoracic aorta were operated on. The group comprised 3 men and 3 women with a mean age of 67.6 years. There were 4 patients with an aneurysm of the aortic arch, 1 with chronic ascending aortic dissection, and 1 with progressive aortic valve stenosis. The interval between previous CABG and aortic surgery was 74.0 +/- 44.2 months. All reoperations were performed via median resternotomy. Myocardial protection was obtained by hypothermic perfusion of patent in-situ arterial grafts following cold-blood cardioplegia administration via the aortic root under aortic cross clamping. The operative procedure was aortic arch replacement in 4 patients, ascending aortic replacement with double CABG in 1, and aortic valve replacement in 1. All patients survived the reoperation. Postoperative maximum creatine kinase-MB was 49.2 +/- 29.8 and no new Q-waves occurred in the electrocardiogram nor were any new wall motion abnormalities recognized on echocardiography. There were no late deaths during a follow-up of 30.7 months. Reoperative aortic procedures after CABG can be performed safely with myocardial protection via hypothermic perfusion of a patent in-situ arterial graft.

  12. Graft-versus-host disease

    MedlinePlus

    GVHD; Bone marrow transplant - graft-versus-host disease; Stem cell transplant - graft-versus-host disease; Allogeneic transplant - ... GVHD may occur after a bone marrow, or stem cell, transplant in which someone receives bone marrow ...

  13. SU-E-T-538: Evaluation of IMRT Dose Calculation Based on Pencil-Beam and AAA Algorithms.

    PubMed

    Yuan, Y; Duan, J; Popple, R; Brezovich, I

    2012-06-01

    To evaluate the accuracy of dose calculation for intensity modulated radiation therapy (IMRT) based on Pencil Beam (PB) and Analytical Anisotropic Algorithm (AAA) computation algorithms. IMRT plans of twelve patients with different treatment sites, including head/neck, lung and pelvis, were investigated. For each patient, dose calculation with PB and AAA algorithms using dose grid sizes of 0.5 mm, 0.25 mm, and 0.125 mm, were compared with composite-beam ion chamber and film measurements in patient specific QA. Discrepancies between the calculation and the measurement were evaluated by percentage error for ion chamber dose and γ〉l failure rate in gamma analysis (3%/3mm) for film dosimetry. For 9 patients, ion chamber dose calculated with AAA-algorithms is closer to ion chamber measurement than that calculated with PB algorithm with grid size of 2.5 mm, though all calculated ion chamber doses are within 3% of the measurements. For head/neck patients and other patients with large treatment volumes, γ〉l failure rate is significantly reduced (within 5%) with AAA-based treatment planning compared to generally more than 10% with PB-based treatment planning (grid size=2.5 mm). For lung and brain cancer patients with medium and small treatment volumes, γ〉l failure rates are typically within 5% for both AAA and PB-based treatment planning (grid size=2.5 mm). For both PB and AAA-based treatment planning, improvements of dose calculation accuracy with finer dose grids were observed in film dosimetry of 11 patients and in ion chamber measurements for 3 patients. AAA-based treatment planning provides more accurate dose calculation for head/neck patients and other patients with large treatment volumes. Compared with film dosimetry, a γ〉l failure rate within 5% can be achieved for AAA-based treatment planning. © 2012 American Association of Physicists in Medicine.

  14. The two faces of hydrogen-bond strength on triple AAA-DDD arrays.

    PubMed

    Lopez, Alfredo Henrique Duarte; Caramori, Giovanni Finoto; Coimbra, Daniel Fernando; Parreira, Renato Luis Tame; da Silva, Éder Henrique

    2013-12-02

    Systems that are connected through multiple hydrogen bonds are the cornerstone of molecular recognition processes in biology, and they are increasingly being employed in supramolecular chemistry, specifically in molecular self-assembly processes. For this reason, the effects of different substituents (NO2, CN, F, Cl, Br, OCH3 and NH2) on the electronic structure, and consequently on the magnitude of hydrogen bonds in triple AAA-DDD arrays (A=acceptor, D=donor) were evaluated in the light of topological [electron localization function (ELF) and quantum theory of atoms in molecules (QTAIM)], energetic [Su-Li energy-decomposition analysis (EDA) and natural bond orbital analysis (NBO)], and geometrical analysis. The results based on local H-bond descriptors (geometries, QTAIM, ELF, and NBO) indicate that substitutions with electron-withdrawing groups on the AAA module tend to strengthen, whereas electron-donating substituents tend to weaken the covalent character of the AAA-DDD intermolecular H-bonds, and also indicate that the magnitude of the effect is dependent on the position of substitution. In contrast, Su-Li EDA results show an opposite behavior when compared to local H-bond descriptors, indicating that electron-donating substituents tend to increase the magnitude of H-bonds in AAA-DDD arrays, and thus suggesting that the use of local H-bond descriptors describes the nature of H bonds only partially, not providing enough insight about the strength of such H bonds. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Computer-assisted revision total knee replacement.

    PubMed

    Sikorski, J M

    2004-05-01

    A technique for performing allograft-augmented revision total knee replacement (TKR) using computer assistance is described, on the basis of the results in 14 patients. Bone deficits were made up with impaction grafting. Femoral grafting was made possible by the construction of a retaining wall or dam which allowed pressurisation and retention of the graft. Tibial grafting used a mixture of corticocancellous and morsellised allograft. The position of the implants was monitored by the computer system and adjusted while the cement was setting. The outcome was determined using a six-parameter, quantitative technique (the Perth CT protocol) which measured the alignment of the prosthesis and provided an objective score. The final outcomes were not perfect with errors being made in femoral rotation and in producing a mismatch between the femoral and tibial components. In spite of the shortcomings the alignments were comparable in accuracy with those after primary TKR. Computer assistance shows considerable promise in producing accurate alignment in revision TKR with bone deficits.

  16. Antibacterial and cytotoxic activity of isoprenylated coumarin mammea A/AA isolated from Mammea africana.

    PubMed

    Canning, Corene; Sun, Shi; Ji, Xiangming; Gupta, Smiti; Zhou, Kequan

    2013-05-02

    The stem bark of Mammea africana is widely distributed in tropical Africa and commonly used in traditional medicine. This study aims to identify the active compound in Mammea africana and to evaluate its antimicrobial and antiproliferative activity. Methanol extract from the bark of the Mammea africana was separated by liquid-liquid extraction, followed by open column chromatography. A principal antimicrobial compound was purified by high performance liquid chromatography (HPLC) and its structure was elucidated by nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). The antibacterial activity of the purified compound was determined using the broth microdilution method against 7 common pathogenic bacteria. The compound was also evaluated for cytotoxicity by cell proliferation assay (MTS) using the mouse embryonic fibroblast cell line NIH 3T3 and the non-small cell lung cancer cell line A549. The purified active compound was determined to be mammea A/AA and was found to be highly active against Campylobacter jejuni (MIC=0.5 μg/ml), Streptococcus pneumoniae (MIC=0.25 μg/ml), and Clostridium difficile (MIC=0.25 μg/ml). The compound exhibited significant antiproliferative activities against both NIH 3T3 and A549 cell lines. Mammea A/AA isolated from Mammea africana exerts specific inhibitory activity against Campylobacter jejuni, Streptococcus pneumoniae, and Campylobacter difficile. Mammea A/AA was also found to exhibit significant cytotoxicity against both cancer and normal cell lines. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  17. Structural Insights into the Allosteric Operation of the Lon AAA+ Protease.

    PubMed

    Lin, Chien-Chu; Su, Shih-Chieh; Su, Ming-Yuan; Liang, Pi-Hui; Feng, Chia-Cheng; Wu, Shih-Hsiung; Chang, Chung-I

    2016-05-03

    The Lon AAA+ protease (LonA) is an evolutionarily conserved protease that couples the ATPase cycle into motion to drive substrate translocation and degradation. A hallmark feature shared by AAA+ proteases is the stimulation of ATPase activity by substrates. Here we report the structure of LonA bound to three ADPs, revealing the first AAA+ protease assembly where the six protomers are arranged alternately in nucleotide-free and bound states. Nucleotide binding induces large coordinated movements of conserved pore loops from two pairs of three non-adjacent protomers and shuttling of the proteolytic groove between the ATPase site and a previously unknown Arg paddle. Structural and biochemical evidence supports the roles of the substrate-bound proteolytic groove in allosteric stimulation of ATPase activity and the conserved Arg paddle in driving substrate degradation. Altogether, this work provides a molecular framework for understanding how ATP-dependent chemomechanical movements drive allosteric processes for substrate degradation in a major protein-destruction machine. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Identification of a Degradation Signal Sequence within Substrates of the Mitochondrial i-AAA Protease.

    PubMed

    Rampello, Anthony J; Glynn, Steven E

    2017-03-24

    The i-AAA protease is a component of the mitochondrial quality control machinery that regulates respiration, mitochondrial dynamics, and protein import. The protease is required to select specific substrates for degradation from among the diverse complement of proteins present in mitochondria, yet the rules that govern this selection are unclear. Here, we reconstruct the yeast i-AAA protease, Yme1p, to examine the in vitro degradation of two intermembrane space chaperone subunits, Tim9 and Tim10. Yme1p degrades Tim10 more rapidly than Tim9 despite high sequence and structural similarity, and loss of Tim10 is accelerated by the disruption of conserved disulfide bonds within the substrate. An unstructured N-terminal region of Tim10 is necessary and sufficient to target the substrate to the protease through recognition of a short phenylalanine-rich motif, and the presence of similar motifs in other small Tim proteins predicts robust degradation by the protease. Together, these results identify the first specific degron sequence within a native i-AAA protease substrate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The plant i-AAA protease controls the turnover of an essential mitochondrial protein import component.

    PubMed

    Opalińska, Magdalena; Parys, Katarzyna; Murcha, Monika W; Jańska, Hanna

    2018-01-29

    Mitochondria are multifunctional organelles that play a central role in energy metabolism. Owing to the life-essential functions of these organelles, mitochondrial content, quality and dynamics are tightly controlled. Across the species, highly conserved ATP-dependent proteases prevent malfunction of mitochondria through versatile activities. This study focuses on a molecular function of the plant mitochondrial inner membrane-embedded AAA protease (denoted i -AAA) FTSH4, providing its first bona fide substrate. Here, we report that the abundance of the Tim17-2 protein, an essential component of the TIM17:23 translocase (Tim17-2 together with Tim50 and Tim23), is directly controlled by the proteolytic activity of FTSH4. Plants that are lacking functional FTSH4 protease are characterized by significantly enhanced capacity of preprotein import through the TIM17:23-dependent pathway. Taken together, with the observation that FTSH4 prevents accumulation of Tim17-2, our data point towards the role of this i -AAA protease in the regulation of mitochondrial biogenesis in plants. © 2018. Published by The Company of Biologists Ltd.

  20. Inflammatory cell phenotypes in AAAs: their role and potential as targets for therapy.

    PubMed

    Dale, Matthew A; Ruhlman, Melissa K; Baxter, B Timothy

    2015-08-01

    Abdominal aortic aneurysms (AAAs) are characterized by chronic inflammatory cell infiltration. AAA is typically an asymptomatic disease and caused ≈15 000 deaths annually in the United States. Previous studies have examined both human and murine aortic tissue for the presence of various inflammatory cell types. Studies show that in both human and experimental AAAs, prominent inflammatory cell infiltration, such as CD4(+) T cells and macrophages, occurs in the damaged aortic wall. These cells have the ability to undergo phenotypic modulation based on microenvironmental cues, potentially influencing disease progression. Proinflammatory CD4(+) T cells and classically activated macrophages dominate the landscape of aortic infiltrates. The skew to proinflammatory phenotypes alters disease progression and plays a role in causing chronic inflammation. The local cytokine production and presence of inflammatory mediators, such as extracellular matrix breakdown products, influence the uneven balance of the inflammatory infiltrate phenotypes. Understanding and developing new strategies that target the proinflammatory phenotype could provide useful therapeutic targets for a disease with no current pharmacological intervention. © 2015 American Heart Association, Inc.

  1. Endothelial MMP-9 drives the inflammatory response in abdominal aortic aneurysm (AAA).

    PubMed

    Ramella, Martina; Boccafoschi, Francesca; Bellofatto, Kevin; Md, Antonia Follenzi; Fusaro, Luca; Boldorini, Renzo; Casella, Francesco; Porta, Carla; Settembrini, Piergiorgio; Cannas, Mario

    2017-01-01

    Progression of abdominal aortic aneurysm (AAA) is typified by chronic inflammation and extracellular matrix (ECM) degradation of the aortic wall. Vascular inflammation involves complex interactions among inflammatory cells, endothelial cells (ECs), vascular smooth muscle cells (vSMCs), and ECM. Although vascular endothelium and medial neoangiogenesis play a key role in AAA, the molecular mechanisms underlying their involvement are only partially understood. In AAA biopsies, we found increased MMP-9, IL-6, and monocyte chemoattractant protein-1 (MCP-1), which correlated with massive medial neo-angiogenesis (C4d positive staining). In this study, we developed an in vitro model in order to characterize the role of endothelial matrix metalloproteinase-9 (e-MMP-9) as a potential trigger of medial disruption and in the inflammatory response bridging between ECs and vSMC. Lentiviral-mediated silencing of e-MMP-9 through RNA interference inhibited TNF-alpha-mediated activation of NF-κB in EA.hy926 human endothelial cells. In addition, EA.hy926 cells void of MMP-9 failed to migrate in a 3D matrix. Moreover, silenced EA.hy926 affected vSMC behavior in terms of matrix remodeling. In fact, also MMP-9 in vSMC resulted inhibited when endothelial MMP-9 was suppressed.

  2. Assessment of resistomycin, as an anticancer compound isolated and characterized from Streptomyces aurantiacus AAA5.

    PubMed

    Vijayabharathi, Rajendran; Bruheim, Per; Andreassen, Trygve; Raja, Duraisamy Senthil; Devi, Palanisamy Bruntha; Sathyabama, Sathyaseelan; Priyadarisini, Venkatesan Brindha

    2011-12-01

    A new actinomycete strain, isolated from humus soils in the Western Ghats, was found to be an efficient pigment producer. The strain, designated AAA5, was identified as a putative Streptomyces aurantiacus strain based on cultural properties, morphology, carbon source utilization, and analysis of the 16S rRNA gene. The strain produced a reddish-brown pigmented compound during the secondary metabolites phase. A yellow compound was derived from the extracted pigment and was identified as the quinone-related antibiotic resistomycin based on ultraviolet-visible spectrophotometry, fourier transform infrared spectroscopy, liquid chromatography and mass spectroscopy, and nuclear magnetic resonance analyses. The AAA5 strain was found to produce large quantities of resistomycin (52.5 mg/L). It showed potent cytotoxic activity against cell lines viz. HepG2 (hepatic carcinoma) and HeLa (cervical carcinoma) in vitro, with growth inhibition (GI(50)) of 0.006 and 0.005 μg/ml, respectively. The strain also exhibited broad antimicrobial activities against both Gram-positive and Gram-negative bacteria. Therefore, AAA5 may have great potential as an industrial resistomycin-producing strain.

  3. A pull-back algorithm to determine the unloaded vascular geometry in anisotropic hyperelastic AAA passive mechanics.

    PubMed

    Riveros, Fabián; Chandra, Santanu; Finol, Ender A; Gasser, T Christian; Rodriguez, Jose F

    2013-04-01

    Biomechanical studies on abdominal aortic aneurysms (AAA) seek to provide for better decision criteria to undergo surgical intervention for AAA repair. More accurate results can be obtained by using appropriate material models for the tissues along with accurate geometric models and more realistic boundary conditions for the lesion. However, patient-specific AAA models are generated from gated medical images in which the artery is under pressure. Therefore, identification of the AAA zero pressure geometry would allow for a more realistic estimate of the aneurysmal wall mechanics. This study proposes a novel iterative algorithm to find the zero pressure geometry of patient-specific AAA models. The methodology allows considering the anisotropic hyperelastic behavior of the aortic wall, its thickness and accounts for the presence of the intraluminal thrombus. Results on 12 patient-specific AAA geometric models indicate that the procedure is computational tractable and efficient, and preserves the global volume of the model. In addition, a comparison of the peak wall stress computed with the zero pressure and CT-based geometries during systole indicates that computations using CT-based geometric models underestimate the peak wall stress by 59 ± 64 and 47 ± 64 kPa for the isotropic and anisotropic material models of the arterial wall, respectively.

  4. Structural Insights into the Unusually Strong ATPase Activity of the AAA Domain of the Caenorhabditis elegans Fidgetin-like 1 (FIGL-1) Protein*

    PubMed Central

    Peng, Wentao; Lin, Zhijie; Li, Weirong; Lu, Jing; Shen, Yuequan; Wang, Chunguang

    2013-01-01

    The FIGL-1 (fidgetin like-1) protein is a homolog of fidgetin, a protein whose mutation leads to multiple developmental defects. The FIGL-1 protein contains an AAA (ATPase associated with various activities) domain and belongs to the AAA superfamily. However, the biological functions and developmental implications of this protein remain unknown. Here, we show that the AAA domain of the Caenorhabditis elegans FIGL-1 protein (CeFIGL-1-AAA), in clear contrast to homologous AAA domains, has an unusually high ATPase activity and forms a hexamer in solution. By determining the crystal structure of CeFIGL-1-AAA, we found that the loop linking helices α9 and α10 folds into the short helix α9a, which has an acidic surface and interacts with a positively charged surface of the neighboring subunit. Disruption of this charge interaction by mutagenesis diminishes both the ATPase activity and oligomerization capacity of the protein. Interestingly, the acidic residues in helix α9a of CeFIGL-1-AAA are not conserved in other homologous AAA domains that have relatively low ATPase activities. These results demonstrate that the sequence of CeFIGL-1-AAA has adapted to establish an intersubunit charge interaction, which contributes to its strong oligomerization and ATPase activity. These unique properties of CeFIGL-1-AAA distinguish it from other homologous proteins, suggesting that CeFIGL-1 may have a distinct biological function. PMID:23979136

  5. Structural insights into the unusually strong ATPase activity of the AAA domain of the Caenorhabditis elegans fidgetin-like 1 (FIGL-1) protein.

    PubMed

    Peng, Wentao; Lin, Zhijie; Li, Weirong; Lu, Jing; Shen, Yuequan; Wang, Chunguang

    2013-10-11

    The FIGL-1 (fidgetin like-1) protein is a homolog of fidgetin, a protein whose mutation leads to multiple developmental defects. The FIGL-1 protein contains an AAA (ATPase associated with various activities) domain and belongs to the AAA superfamily. However, the biological functions and developmental implications of this protein remain unknown. Here, we show that the AAA domain of the Caenorhabditis elegans FIGL-1 protein (CeFIGL-1-AAA), in clear contrast to homologous AAA domains, has an unusually high ATPase activity and forms a hexamer in solution. By determining the crystal structure of CeFIGL-1-AAA, we found that the loop linking helices α9 and α10 folds into the short helix α9a, which has an acidic surface and interacts with a positively charged surface of the neighboring subunit. Disruption of this charge interaction by mutagenesis diminishes both the ATPase activity and oligomerization capacity of the protein. Interestingly, the acidic residues in helix α9a of CeFIGL-1-AAA are not conserved in other homologous AAA domains that have relatively low ATPase activities. These results demonstrate that the sequence of CeFIGL-1-AAA has adapted to establish an intersubunit charge interaction, which contributes to its strong oligomerization and ATPase activity. These unique properties of CeFIGL-1-AAA distinguish it from other homologous proteins, suggesting that CeFIGL-1 may have a distinct biological function.

  6. Prosthetic replacement of the infrahepatic inferior vena cava for leiomyosarcoma.

    PubMed

    Illuminati, Giulio; Calio', Francesco G; D'Urso, Antonio; Giacobbi, Daniela; Papaspyropoulos, Vassilios; Ceccanei, Gianluca

    2006-09-01

    Resection of the infrahepatic inferior vena cava associated with prosthetic graft replacement for caval leiomyosarcoma is an acceptable procedure to obtain prolonged and good-quality survival. A consecutive sample clinical study with a mean follow-up of 40 months. The surgical department of an academic tertiary center and an affiliated secondary care center. Eleven patients, with a mean age of 51 years, who have primary leiomyosarcoma of the infrahepatic inferior vena cava. All of the patients underwent radical resection of the tumor en bloc with the affected segment of the vena cava. Reconstruction consisted of 10 cavocaval polytetrafluoroethylene grafts and 1 cavobiliac graft. An associated right nephrectomy was performed in 2 cases. The left renal vein was reimplanted in the graft in 3 cases. Cumulative disease-specific survival, disease-free survival, and graft patency rates expressed by standard life-table analysis. No patients died in the postoperative period. The cumulative (SE) disease-specific survival rate was 53% (21%) at 5 years. The cumulative (SE) disease-free survival rate was 44% (19%) at 5 years. The cumulative (SE) graft patency rate was 67% (22%) at 5 years. Radical resection followed by prosthetic graft reconstruction is a valuable method for treating primary leiomyosarcoma of the infrahepatic inferior vena cava.

  7. New Polytetrahydrofuran Graft Copolymers.

    DTIC Science & Technology

    1979-03-15

    chioroprene) , chiorobutyl - ~~~~~ rubber , bromobutyl rubber , chlorinated EPDM , chlorinated poly(buta— diene) and chlorinated butadiene styrene copolymer...bromobutyl rubber , which after dehalogenation is unstable with respect to conjugated dienes, the yields of graft copolymer are low. With poly(chloroprerte

  8. Acrylonitrile grafted to PVDF

    DOEpatents

    Yang, Jin; Eitouni, Hany Basam

    2015-03-31

    PVDF-g-PAN has been synthesized by grafting polyacrylonitrile onto polyvinylidene fluoride using an ATRP/AGET method. The novel polymer is ionically conducive and has much more flexibility than PVDF alone, making it especially useful either as a binder in battery cell electrodes or as a polymer electrolyte in a battery cell.

  9. A comparative analysis of the outcomes of aortic cuffs and converters for endovascular graft migration.

    PubMed

    Thomas, Bradley G; Sanchez, Luis A; Geraghty, Patrick J; Rubin, Brian G; Money, Samuel R; Sicard, Gregorio A

    2010-06-01

    Proximal attachment failure, often leading to graft migration, is a severe complication of endovascular aneurysm repair (EVAR). Aortic cuffs have been used to treat proximal attachment failure with mixed results. The Zenith Renu AAA Ancillary Graft (Cook Inc, Bloomington, Ind) is available in two configurations: converter and main body extension. Both provide proximal extension with active fixation for the treatment of pre-existing endovascular grafts with failed or failing proximal fixation or seal in patients who are not surgical candidates. We prospectively compared the outcomes of patient treatment with these two device configurations. From September 2005 to May 2008, a prospective, nonrandomized, postmarket registry was conducted to collect data from 151 patients treated at 95 institutions for proximal aortic endovascular graft failure using the Renu graft. Treatment indications included inadequate proximal fixation or seal, for example, migration, and type I and III endoleak. A total of 136 patients (90%) had migration, 111 (74%) had endoleak, and 94 (62%) had endoleaks and graft migration. AneuRx grafts were present in 126 patients (83%), of which 89 (59%) were treated with a converter and 62 (41%) with a main body extension. Outcomes using converters vs main body extensions for endoleak rates, changes in aneurysm size, and ruptures were compared. Preprocedural demographics between the two groups did not differ significantly. Procedural success rates were 98% for the converter group and 100% for the main body extension group. At a mean follow-up of 12.8 +/- 7.5 months, no type III endoleaks (0%)were identified in the converter group, and five (8%) were identified in the main body extension group. There were no aneurysm ruptures in patients treated with converters (0%) and three ruptures (5%) in patients treated with main body extensions. Each patient with aneurysm rupture had been treated with a Renu main body extension, developed a type III endoleak, and

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

    PubMed Central

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

    2014-01-01

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

  11. Nonlinear and Anisotropic Tensile Properties of Graft Materials used in Soft Tissue Applications

    PubMed Central

    Yoder, Jonathon H; Elliott, Dawn M

    2010-01-01

    Background The mechanical properties of extracellular matrix grafts that are intended to augment or replace soft tissues should be comparable to the native tissue. Such grafts are often used in fiber-reinforced tissue applications that undergo multi-axial loading and therefore knowledge of the anisotropic and nonlinear properties are needed, including the moduli and Poisson's ratio in two orthogonal directions within the plane of the graft. The objective of this study was to measure the tensile mechanical properties of several marketed grafts: Alloderm, Restore, CuffPatch, and OrthADAPT. Methods The degree of anisotropy and nonlinearity within each graft was evaluated from uniaxial tensile tests and compared to their native tissue. Results The Alloderm graft was anisotropic in both the toe and linear-region of the stress-strain response, was highly nonlinear, and generally had low properties. The Restore and CuffPatch grafts had similar stress-strain responses, were largely isotropic, had a linear-region modulus of 18 MPa, and were nonlinear. OrthADAPT was anisotropic in the linear region (131 vs 47 MPa) and was highly nonlinear. The Poisson ratio for all grafts was between 0.4 and 0.7, except for the parallel orientation of Restore which was greater than 1.0. Interpretation Having an informed understanding of how the available grafts perform mechanically will allow for better assessment by the physician for which graft to apply depending upon its application. PMID:20129728

  12. SU-F-T-609: Impact of Dosimetric Variation for Prescription Dose Using Analytical Anisotropic Algorithm (AAA) in Lung SBRT

    SciTech Connect

    Kawai, D; Takahashi, R; Kamima, T

    Purpose: Actual irradiated prescription dose to patients cannot be verified. Thus, independent dose verification and second treatment planning system are used as the secondary check. AAA dose calculation engine has contributed to lung SBRT. We conducted a multi-institutional study to assess variation of prescription dose for lung SBRT when using AAA in reference to using Acuros XB and Clarkson algorithm. Methods: Six institutes in Japan participated in this study. All SBRT treatments were planed using AAA in Eclipse and Adaptive Convolve (AC) in Pinnacle3. All of the institutes used a same independent dose verification software program (Simple MU Analysis: SMU,more » Triangle Product, Ishikawa, Japan), which implemented a Clarkson-based dose calculation algorithm using CT image dataset. A retrospective analysis for lung SBRT plans (73 patients) was performed to compute the confidence limit (CL, Average±2SD) in dose between the AAA and the SMU. In one of the institutes, a additional analysis was conducted to evaluate the variations between the AAA and the Acuros XB (AXB). Results: The CL for SMU shows larger systematic and random errors of 8.7±9.9 % for AAA than the errors of 5.7±4.2 % for AC. The variations of AAA correlated with the mean CT values in the voxels of PTV (a correlation coefficient : −0.7) . The comparison of AXB vs. AAA shows smaller systematic and random errors of −0.7±1.7%. The correlation between dose variations for AXB and the mean CT values in PTV was weak (0.4). However, there were several plans with more than 2% deviation of AAPM TG114 (Maximum: −3.3 %). Conclusion: In comparison for AC, prescription dose calculated by AAA may be more variable in lung SBRT patient. Even AXB comparison shows unexpected variation. Care should be taken for the use of AAA in lung SBRT. This research is partially supported by Japan Agency for Medical Research and Development (AMED)« less

  13. Bladder Mucosal Graft Vaginoplasty: A Case Report.

    PubMed

    Chiaramonte, Cinzia; Vestri, Elettra; Tripi, Flavia; Giannone, Antonino Giulio; Cimador, Marcello; Cataliotti, Ferdinando

    2018-06-18

    Female vaginoplasty reconstruction, by choice, is usually performed with adjacent tissue. However in some clinical conditions such as high urogenital confluence sinus, cloacal malformation with extreme vaginal hypoplasia, local tissue may not be available. When vaginal replacement is performed in pediatric patients intestinal segments is preferred to non-operative procedures that require continuative dilations. However mucus production, malignant transformation risk and diversion colitis are important side effects. We present a nouvel technique for vaginoplasty in a female child presenting with an isolated urogenital sinus malformation without virilization. The patient at 20 months underwent vaginoplasty using tubularized bladder mucosal graft. Surgical procedure was devoid of complications. Pubertal development occurred at age of 15. She underwent regular follow up until 18 years of age. At this age we performed clinical evaluation: absence of vaginal introitus stenosis and good cosmetic results were observed. Then she underwent vaginoscopy with multiple biopsies. Pathology examination of the bladder mucosal graft evidenced a normal structure of the mucosa, with a stratified squamous epithelium. Different techniques are taken into account for vaginal reconstruction according to the severity and to the type of malformation. We describe the use of bladder mucosal graft with favorable results after long term follow-up. Copyright © 2018. Published by Elsevier Inc.

  14. Acellular vascular matrix grafts from human placenta chorion: Impact of ECM preservation on graft characteristics, protein composition and in vivo performance.

    PubMed

    Schneider, Karl H; Enayati, Marjan; Grasl, Christian; Walter, Ingrid; Budinsky, Lubos; Zebic, Gabriel; Kaun, Christoph; Wagner, Anja; Kratochwill, Klaus; Redl, Heinz; Teuschl, Andreas H; Podesser, Bruno K; Bergmeister, Helga

    2018-05-29

    Small diameter vascular grafts from human placenta, decellularized with either Triton X-100 (Triton) or SDS and crosslinked with heparin were constructed and characterized. Graft biochemical properties, residual DNA, and protein composition were evaluated to compare the effect of the two detergents on graft matrix composition and structural alterations. Biocompatibility was tested in vitro by culturing the grafts with primary human macrophages and in vivo by subcutaneous implantation of graft conduits (n = 7 per group) into the flanks of nude rats. Subsequently, graft performance was evaluated using an aortic implantation model in Sprague Dawley rats (one month, n = 14). In situ graft imaging was performed using MRI angiography. Retrieved specimens were analyzed by electromyography, scanning electron microscopy, histology and immunohistochemistry to evaluate cell migration and the degree of functional tissue remodeling. Both decellularization methods resulted in grafts of excellent biocompatibility in vitro and in vivo, with low immunogenic potential. Proteomic data revealed removal of cytoplasmic proteins with relative enrichment of ECM proteins in decelluarized specimens of both groups. Noteworthy, LC-Mass Spectrometry analysis revealed that 16 proteins were exclusively preserved in Triton decellularized specimens in comparison to SDS-treated specimens. Aortic grafts showed high patency rates, no signs of thrombus formation, aneurysms or rupture. Conduits of both groups revealed tissue-specific cell migration indicative of functional remodeling. This study strongly suggests that decellularized allogenic grafts from the human placenta have the potential to be used as vascular replacement materials. Both detergents produced grafts with low residual immunogenicity and appropriate mechanical properties. Observed differences in graft characteristics due to preservation method had no impact on successful in vivo performance in the rodent model. Copyright

  15. Characterization of the binding specificity of Anguilla anguilla agglutinin (AAA) in comparison to Ulex europaeus agglutinin I (UEA-I).

    PubMed

    Baldus, S E; Thiele, J; Park, Y O; Hanisch, F G; Bara, J; Fischer, R

    1996-08-01

    Using immunochemical and immunohistochemical methods, the binding site of Anguilla anguilla agglutinin (AAA) was characterized and compared with the related fucose-specific lectin from Ulex europaeus (UEA-I). In solid-phase enzyme-linked immunoassays, the two lectins recognized Fuc alpha 1-2Gal beta-HSA. AAA additionally cross-reacted with neoglycolipids bearing lacto-N-fucopentaose (LNFP) I [H type 1] and II [Le(a)] and lactodifucotetraose (LDFT) as glycan moieties. UEA-I, on the other hand, bound to a LDFT-derived neoglycolipid but not to the other neoglycolipids tested. Binding of AAA to gastric mucin was competitively neutralized by Le(a)-specific monoclonal antibodies. UEA-I binding, on the other hand, was reduced after co-incubation with H type 2- and Le(y)-specific monoclonal antibodies. According to our results, AAA reacts with fucosylated type 1 chain antigens, whereas UEA-I binds only to the alpha 1-2-fucosylated LDFT-derived neoglycolipid. In immunohistochemical studies, the reactivity of AAA and UEA-I in normal pyloric mucosa from individuals with known Lewis and secretor status was analysed. AAA showed a broad reaction in the superficial pyloric mucosa from secretors and non-secretors, but AAA reactivity was more pronounced in Le(a+b-) individuals. On the other hand, UEA-I stained the superficial pyloric mucosa only from secretor individuals. A staining of deep mucous glands by the lectins was found in all specimens. Both reacted with most human carcinomas of different origin. Slight differences in their binding pattern were observed and may be explained by the different fine-specificities of the lectins.

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

    PubMed

    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 (p<0.05) in burn injured wounds. Histological analysis supported objective clinical findings with marked scar-like collagen proliferation within the dermis, increased vascular density, and prolonged and increased cellular infiltration. Observed differences in contracture also correlated with earlier and more prominent myofibroblast differentiation as demonstrated by α-SMA staining. Antecedent thermal injury worsens split-thickness skin 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

  17. Hip Replacement Surgery

    MedlinePlus

    ... Download Download EPUB Download PDF What is it? Points To Remember About Hip Replacement Surgery Hip replacement ... This leaves your hands and arms free for balance or to use crutches. Use a long-handled " ...

  18. Partial knee replacement - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100225.htm Partial knee replacement - series—Normal anatomy To use the sharing ... A.M. Editorial team. Related MedlinePlus Health Topics Knee Replacement A.D.A.M., Inc. is accredited ...

  19. Prosthetic valve sparing aortic root replacement: an improved technique.

    PubMed

    Leacche, Marzia; Balaguer, Jorge M; Umakanthan, Ramanan; Byrne, John G

    2008-10-01

    We describe a modified surgical technique to treat patients with a previous history of isolated aortic valve replacement who now require aortic root replacement for an aneurysmal or dissected aorta. This technique consists of replacing the aortic root with a Dacron conduit, leaving intact the previously implanted prosthesis, and re-implanting the coronary arteries in the Dacron graft. Our technique differs from other techniques in that we do not leave behind any aortic tissue remnant and also in that we use a felt strip to obliterate any gap between the old sewing ring and the newly implanted graft. In our opinion, this promotes better hemostasis. We demonstrate that this technique is safe, feasible, and results in acceptable outcomes.

  20. Family Members of Patients with Abdominal Aortic Aneurysms are at Increased Risk for Aneurysms: Analysis of 618 Probands and their Families from the Liège AAA Family Study

    PubMed Central

    Sakalihasan, Natzi; Defraigne, Jean-Olivier; Kerstenne, Marie-Ange; Cheramy-Bien, Jean-Paul; Smelser, Diane T.; Tromp, Gerard; Kuivaniemi, Helena

    2014-01-01

    Background The objectives were to answer the following questions using a well-characterized population in Liège, Belgium: 1) what percentage of abdominal aortic aneurysm (AAA) patients have a positive family history for AAA, 2) what is the prevalence of AAAs among relatives of AAA patients; and 3) do familial and sporadic AAA cases differ in clinical characteristics. Methods and Results Unrelated AAA patients diagnosed at the Cardiovascular Surgery Department, University Hospital of Liège, Belgium, between 1999 and 2012 were invited to the study. A detailed family history was obtained in interviews and recorded using Progeny software. In the initial interview 62 (10%) of the 618 AAA patients reported a positive family history for AAA. We divided the 618 patients into two study groups: Group I: 296 AAA patients (268; 91% males) were followed up with computerized tomography combined with positron emission tomography, and Group II: 322 AAA patients (295; 92% males) whose families were invited to ultrasonography screening. Ultrasonography screening identified 24 new AAAs among 186 relatives (≥ 50 years) of 144 families yielding a prevalence of 13%. The highest prevalence (25%) was found among brothers. By combining the number of AAAs found by ultrasonography screening with those diagnosed previously the observed lifetime prevalence of AAA was estimated to be 32% in brothers. The familial AAA cases were more likely to have a ruptured AAA than the sporadic cases (8% vs. 2.4%; P<0.0001). Conclusions The findings confirm previously found high prevalence of AAA among brothers, support genetic contribution to AAA pathogenesis and provide rationale for targeted screening of relatives of AAA patients. PMID:24365082

  1. Family members of patients with abdominal aortic aneurysms are at increased risk for aneurysms: analysis of 618 probands and their families from the Liège AAA Family Study.

    PubMed

    Sakalihasan, Natzi; Defraigne, Jean-Olivier; Kerstenne, Marie-Ange; Cheramy-Bien, Jean-Paul; Smelser, Diane T; Tromp, Gerard; Kuivaniemi, Helena

    2014-05-01

    The objectives were to answer the following questions with the help of a well-characterized population in Liège, Belgium: 1) what percentage of patients with abdominal aortic aneurysm (AAA) have a positive family history for AAA? 2) what is the prevalence of AAAs among relatives of patients with AAA? and 3) do familial and sporadic AAA cases differ in clinical characteristics? Patients with unrelated AAA diagnosed at the Cardiovascular Surgery Department, University Hospital of Liège, Belgium, between 1999 and 2012 were invited to the study. A detailed family history was obtained in interviews and recorded using Progeny software. We divided the 618 patients into 2 study groups: group I, 296 patients with AAA (268; 91% men) were followed up with computerized tomography combined with positron emission tomography; and group II, 322 patients with AAA (295; 92% men) whose families were invited to ultrasonographic screening. In the initial interview, 62 (10%) of the 618 patients with AAA reported a positive family history for AAA. Ultrasonographic screening identified 24 new AAAs among 186 relatives (≥50 years) of 144 families yielding a prevalence of 13%. The highest prevalence (25%) was found among brothers. By combining the number of AAAs found by ultrasonographic screening with those diagnosed previously the observed lifetime prevalence of AAA was estimated to be 32% in brothers. The familial AAA cases were more likely to have a ruptured AAA than the sporadic cases (8% vs. 2.4%; P < 0.0001). The findings confirm previously found high prevalence of AAA among brothers, support genetic contribution to AAA pathogenesis, and provide rationale for targeted screening of relatives of patients with AAA. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Siloxane-grafted membranes

    DOEpatents

    Friesen, D.T.; Obligin, A.S.

    1989-10-31

    Composite cellulosic semipermeable membranes are disclosed which are the covalently bonded reaction product of an asymmetric cellulosic semipermeable membrane and a polysiloxane containing reactive functional group. The two reactants chemically bond by ether, ester, amide or acrylate linkages to form a siloxane-grafted cellulosic membrane having superior selectivity and flux stability. Selectivity may be enhanced by wetting the surface with a swelling agent such as water.

  3. Siloxane-grafted membranes

    DOEpatents

    Friesen, Dwayne T.; Obligin, Alan S.

    1989-01-01

    Composite cellulosic semipermeable membranes are disclosed which are the covalently bonded reaction product of an asymmetric cellulosic semipermeable membrane and a polysiloxane containing reactive functional groups. The two reactants chemically bond by ether, ester, amide or acrylate linkages to form a siloxane-grafted cellulosic membrane having superior selectivity and flux stability. Selectivity may be enhanced by wetting the surface with a swelling agent such as water.

  4. Implementing Replacement Cost Accounting

    DTIC Science & Technology

    1976-12-01

    cost accounting Clickener, John Ross Monterey, California. Naval Postgraduate School http://hdl.handle.net/10945/17810 Downloaded from NPS Archive...Calhoun IMPLEMENTING REPLACEMENT COST ACCOUNTING John Ross CHckener NAVAL POSTGRADUATE SCHOOL Monterey, California THESIS IMPLEMENTING REPLACEMENT COST ...Implementing Replacement Cost Accounting 7. AUTHORS John Ross Clickener READ INSTRUCTIONS BEFORE COMPLETING FORM 3. RECIPIENT’S CATALOG NUMBER 9. TYRE OF

  5. NASA Astrophysics E/PO Impact: NASA SOFIA AAA Program Evaluation Results

    NASA Astrophysics Data System (ADS)

    Harman, Pamela; Backman, Dana E.; Clark, Coral; Inverness Research Sofia Aaa Evaluation Team, Wested Sofia Aaa Evaluation Team

    2015-01-01

    SOFIA is an airborne observatory, studying the universe at infrared wavelengths, capable of making observations that are impossible for even the largest and highest ground-based telescopes. SOFIA also inspires the development of new scientific instrumentation and fosters the education of young scientists and engineers.SOFIA is an 80% - 20% partnership of NASA and the German Aerospace Center (DLR), consisting of an extensively modified Boeing 747SP aircraft carrying a reflecting telescope with an effective diameter of 2.5 meters (100 inches). The SOFIA aircraft is based at NASA Armstrong Flight Research Center, Building 703, in Palmdale, California. The Science Program and Outreach Offices are located at NASA Ames Research center. SOFIA is a program in NASA's Science Mission Directorate, Astrophysics Division.Data will be collected to study many different kinds of astronomical objects and phenomena, including star cycles, solar system formation, identification of complex molecules in space, our solar system, galactic dust, nebulae and ecosystems.Airborne Astronomy Ambassador (AAA) Program:The SOFIA Education and Communications program exploits the unique attributes of airborne astronomy to contribute to national goals for the reform of science, technology, engineering, and math (STEM) education, and to elevate public scientific and technical literacy.The AAA effort is a professional development program aspiring to improve teaching, inspire students, and inform the community. To date, 55 educators from 21 states; Cycles 0, 1 and 2; have completed their astronomy professional development and their SOFIA science flight experience. Evaluation has confirmed the program's positive impact on the teacher participants, on their students, and in their communities. The inspirational experience has positively impacted their practice and career trajectory. AAAs have incorporated content knowledge and specific components of their experience into their curricula, and have given

  6. Morphological State as a Predictor for Reintervention and Mortality After EVAR for AAA

    SciTech Connect

    Ohrlander, Tomas; Dencker, Magnus; Acosta, Stefan, E-mail: stefan.acosta@telia.com

    2012-10-15

    Purpose: This study was designed to assess aorto-iliac morphological characteristics in relation to reintervention and all-cause long-term mortality in patients undergoing standard EVAR for infrarenal AAA. Methods: Patients treated with EVAR (Zenith{sup Registered-Sign} Stentgrafts, Cook) between May 1998 and February 2006 were prospectively enrolled in a computerized database where comorbidities and preoperative aneurysm morphology were entered. Reinterventions and mortality were checked until December 1, 2010. Median follow-up time was 68 months. Results: A total of 304 patients were included, of which 86% were men. Median age was 74 years. The reintervention rate was 23.4% (71/304). A greater diameter of themore » common iliac artery (p = 0.037; hazard ratio (HR) 1.037 [1.002-1.073]) was an independent factor for an increased number of reinterventions. The 30-day mortality rate was 3.0% (9/304). Aneurysm-related deaths due to AAA occurred in 4.9% (15/304). Five patients died due to a concomitant ruptured thoracic aortic aneurysm. The mortality until end of follow-up was 54.3% (165/304). The proportion of deaths caused by vascular diseases was 61.6%. The severity of angulation of the iliac arteries (p = 0.014; HR 1.018 [95% confidence interval (CI) 1.004-1.033]) and anemia (p = 0.044; HR 2.79 [95% CI 1.029-7.556]) remained as independent factors associated with all-cause long-term mortality. The crude reintervention-free survival rate at 1, 3, and 5 years was 84.5%, 64.8%, and 51.6%, respectively. Conclusions: The initial aorto-iliac morphological state in patients scheduled for standard EVAR for AAA seems to be strongly related to the need for reinterventions and long-term mortality.« less

  7. COMBINED REPLACEMENT OF THE AORTIC VALVE AND ASCENDING AORTA IN JEHOVAH'S WITNESSES: REPORT OF TWO CASES

    PubMed Central

    Beddermann, Christoph; Norman, John C.; Cooley, Denton A.

    1979-01-01

    Two Jehovah's Witnesses with large ascending thoracic aortic aneurysms and aortic insufficiency secondary to annuloaortic ectasia underwent successful combined replacement of the aortic valve and the ascending aorta. One patient received a composite graft containing an aortic valve prosthesis, which necessitated supravalvular coronary ostia reimplantation; the other patient underwent separate aortic valve and left supracoronary ascending aneurysm replacement, with reimplantation of the right coronary ostium into the graft. No blood or blood derivatives were administered. Both patients had uneventful recoveries and continue to do well. To our knowledge, they represent the first reported cases of successful combined replacement of the aortic valve and ascending aorta in Jehovah's Witnesses. Images PMID:15216324

  8. Two-step grafting significantly enhances the survival of foetal dopaminergic transplants and induces graft-derived vascularisation in a 6-OHDA model of Parkinson's disease.

    PubMed

    Büchele, Fabian; Döbrössy, Máté; Hackl, Christina; Jiang, Wei; Papazoglou, Anna; Nikkhah, Guido

    2014-08-01

    GFP+ vessels - completely absent in control grafts - in regions where the two grafts overlap, indicating second-graft derived angiogenesis. In summary, the study shows that two-step grafting with a 2days time interval significantly increases DAergic cell survival compared to the standard protocol. Furthermore, our results demonstrate, for the first time, a donor-derived neoangiogenesis, leading to a new understanding of graft survival and development in the field of cell-replacement therapies for neurodegenerative diseases. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Advanced Stent Graft Treatment of Venous Stenosis Affecting Hemodialysis Vascular Access: Case Illustrations

    PubMed Central

    Patel, Darshan; Ray, Charles E.; Lokken, R. Peter; Bui, James T.; Lipnik, Andrew J.; Gaba, Ron C.

    2016-01-01

    Surgically placed dialysis access is an important component of dialysis replacement therapy. The vast majority of patients undergoing dialysis will have surgically placed accesses at some point in the course of their disease, and for many patients these accesses may represent their definitive renal replacement option. Most, if not all, arteriovenous fistulae and grafts will require interventions at some point in time. Percutaneous angioplasty is the typical first treatment performed for venous stenoses, with stents and stent grafts being reserved for patients in whom angioplasty and surgical options are exhausted. In some salvage situations, stent graft placement may be the only or best option for patients. This article describes, using case illustrations, placement of stent grafts in such patients; a focus will also be made on the techniques utilized in such salvage situations. PMID:27011426

  10. Peak AAA fatty acid homolog contaminants present in the dietary supplement l-Tryptophan associated with the onset of eosinophilia-myalgia syndrome.

    PubMed

    Klarskov, Klaus; Gagnon, Hugo; Racine, Mathieu; Boudreault, Pierre-Luc; Normandin, Chad; Marsault, Eric; Gleich, Gerald J; Naylor, Stephen

    2018-05-22

    The eosinophilia-myalgia syndrome (EMS) outbreak that occurred in the USA and elsewhere in 1989 was caused by the ingestion of Showa Denko K.K. (SD) L-tryptophan (L-Trp). "Six compounds" detected in the L-Trp were reported as case-associated contaminants. Recently the final and most statistically significant contaminant, "Peak AAA" was structurally characterized. The "compound" was actually shown to be two structural isomers resulting from condensation reactions of L-Trp with fatty acids derived from the bacterial cell membrane. They were identified as the indole C-2 anteiso (AAA 1 -343) and linear (AAA 2 -343) aliphatic chain isomers. Based on those findings, we utilized a combination of on-line HPLC-electrospray ionization mass spectrometry (LC-MS), as well as both precursor and product ion tandem mass spectrometry (MS/MS) to facilitate identification of a homologous family of condensation products related to AAA 1 -343 and AAA 2 -343. We structurally characterized eight new AAA 1 -XXX/AAA 2 -XXX contaminants, where XXX represents the integer molecular ions of all the related homologs, differing by aliphatic chain length and isomer configuration. The contaminants were derived from the following fatty acids of the bacterial cell membrane, 5-methylheptanoic acid (anteiso-C8:0) for AAA 1 -315; n-octanoic acid (n-C8:0) for AAA 2 -315; 6-methyloctanoic acid (anteiso-C9:0) for AAA 1 -329; n-nonanoic acid (n-C9:0) for AAA 2 -329; 10-methyldodecanoic acid (anteiso-C13:0) for AAA 1 -385; n-tridecanoic acid (n-C13:0) for AAA 2 -385; 11-methyltridecanoic acid (anteiso-C14:0) for AAA 1 -399; and n-tetradecanoic acid (n-C14:0) for AAA 2 -399. The concentration levels for these contaminants were estimated to be 0.1-7.9 μg / 500 mg of an individual SD L-Trp tablet or capsule The structural similarity of these homologs to case-related contaminants of Spanish Toxic Oil Syndrome (TOS) is discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Increased galectin-3 levels are associated with abdominal aortic aneurysm progression and inhibition of galectin-3 decreases elastase-induced AAA development.

    PubMed

    Fernandez-García, Carlos-Ernesto; Tarin, Carlos; Roldan-Montero, Raquel; Martinez-Lopez, Diego; Torres-Fonseca, Monica; Lindhot, Jes S; Vega de Ceniga, Melina; Egido, Jesus; Lopez-Andres, Natalia; Blanco-Colio, Luis-Miguel; Martín-Ventura, Jose-Luis

    2017-11-15

    Abdominal aortic aneurysm (AAA) evolution is unpredictable and no specific treatment exists for AAA, except surgery to prevent aortic rupture. Galectin-3 has been previously associated with CVD, but its potential role in AAA has not been addressed. Galectin-3 levels were increased in the plasma of AAA patients ( n =225) compared with the control group ( n =100). In addition, galectin-3 concentrations were associated with the need for surgical repair, independently of potential confounding factors. Galectin-3 mRNA and protein expression were increased in human AAA samples compared with healthy aortas. Experimental AAA in mice was induced via aortic elastase perfusion. Mice were treated intravenously with the galectin-3 inhibitor modified citrus pectin (MCP, 10 mg/kg, every other day) or saline. Similar to humans, galectin-3 serum and aortic mRNA levels were also increased in elastase-induced AAA mice compared with control mice. Mice treated with MCP showed decreased aortic dilation, as well as elastin degradation, vascular smooth muscle cell (VSMC) loss, and macrophage content at day 14 postelastase perfusion compared with control mice. The underlying mechanism(s) of the protective effect of MCP was associated with a decrease in galectin-3 and cytokine (mainly CCL5) mRNA and protein expression. Interestingly, galectin-3 induced CCL5 expression by a mechanism involving STAT3 activation in VSMC. Accordingly, MCP treatment decreased STAT3 phosphorylation in elastase-induced AAA. In conclusion, increased galectin-3 levels are associated with AAA progression, while galectin-3 inhibition decreased experimental AAA development. Our data suggest the potential role of galectin-3 as a therapeutic target in AAA. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  12. Moyamoya disease-associated protein mysterin/RNF213 is a novel AAA+ ATPase, which dynamically changes its oligomeric state

    NASA Astrophysics Data System (ADS)

    Morito, Daisuke; Nishikawa, Kouki; Hoseki, Jun; Kitamura, Akira; Kotani, Yuri; Kiso, Kazumi; Kinjo, Masataka; Fujiyoshi, Yoshinori; Nagata, Kazuhiro

    2014-03-01

    Moyamoya disease is an idiopathic human cerebrovascular disorder that is characterized by progressive stenosis and abnormal collateral vessels. We recently identified mysterin/RNF213 as its first susceptibility gene, which encodes a 591-kDa protein containing enzymatically active P-loop ATPase and ubiquitin ligase domains and is involved in proper vascular development in zebrafish. Here we demonstrate that mysterin further contains two tandem AAA+ ATPase modules and forms huge ring-shaped oligomeric complex. AAA+ ATPases are known to generally mediate various biophysical and mechanical processes with the characteristic ring-shaped structure. Fluorescence correlation spectroscopy and biochemical evaluation suggested that mysterin dynamically changes its oligomeric forms through ATP/ADP binding and hydrolysis cycles. Thus, the moyamoya disease-associated gene product is a unique protein that functions as ubiquitin ligase and AAA+ ATPase, which possibly contributes to vascular development through mechanical processes in the cell.

  13. Moyamoya disease-associated protein mysterin/RNF213 is a novel AAA+ ATPase, which dynamically changes its oligomeric state

    PubMed Central

    Morito, Daisuke; Nishikawa, Kouki; Hoseki, Jun; Kitamura, Akira; Kotani, Yuri; Kiso, Kazumi; Kinjo, Masataka; Fujiyoshi, Yoshinori; Nagata, Kazuhiro

    2014-01-01

    Moyamoya disease is an idiopathic human cerebrovascular disorder that is characterized by progressive stenosis and abnormal collateral vessels. We recently identified mysterin/RNF213 as its first susceptibility gene, which encodes a 591-kDa protein containing enzymatically active P-loop ATPase and ubiquitin ligase domains and is involved in proper vascular development in zebrafish. Here we demonstrate that mysterin further contains two tandem AAA+ ATPase modules and forms huge ring-shaped oligomeric complex. AAA+ ATPases are known to generally mediate various biophysical and mechanical processes with the characteristic ring-shaped structure. Fluorescence correlation spectroscopy and biochemical evaluation suggested that mysterin dynamically changes its oligomeric forms through ATP/ADP binding and hydrolysis cycles. Thus, the moyamoya disease-associated gene product is a unique protein that functions as ubiquitin ligase and AAA+ ATPase, which possibly contributes to vascular development through mechanical processes in the cell. PMID:24658080

  14. Ascending Aortic Stenting for Acute Supraaortic Stenosis From Graft Collapse.

    PubMed

    Lader, Joshua M; Smith, Deane E; Staniloae, Cezar; Fallahi, Arzhang; Iqbal, Sohah N; Galloway, Aubrey C; Williams, Mathew R

    2018-06-01

    A 78-year-old man with remote type-A dissection presented with acute-onset dyspnea. Twenty-two years prior, treatment for his aortic disease required replacement of ascending and arch aneurysms with a polyester graft (Dacron) using the graft inclusion technique. He presented currently in cardiogenic shock. Echocardiography demonstrated new severe hypokinesis of all apical segments. Left-heart catheterization revealed a 120 mm Hg intragraft gradient. Computed tomography arteriography was unrevealing, but intraaortic ultrasound demonstrated critical intragraft stenosis. A balloon expandable stent (Palmaz stent, Cordis, Milpitas, CA) was deployed in the stenotic region with gradient resolution. The patient later underwent aortic root replacement and ascending aneurysm repair (Bio-Bentall technique) and is doing well at 24 months. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  15. Liver graft vascular variant with 3 extra-hepatic arteries.

    PubMed

    Martins, Paulo N

    2010-06-01

    Vascular anatomy of the liver is varied, and the "standard" anatomy is seen in 55%-80% of cases. It is very important that extrahepatic arteries are identified precisely at the time of graft procurement to avoid injuries that might compromise the liver function. In the present case the liver donor had the vascular anatomy of Michels type VII, e.g. a hepatic artery originating from the celiac trunk and going to the left lobe, an accessory left hepatic artery coming from the left gastric artery, and a replaced right hepatic artery coming from the superior mesenteric artery. This pattern of vascular supply is uncommon, representing less than 5% of cases. The replaced hepatic artery was reconstructed in the back-table with polypropylene suture 7.0 by connecting it to the stump of the splenic artery, and the celiac trunk of the graft was anastomosed to the recipient common hepatic artery.

  16. Science | AAAS

    Science.gov Websites

    be caused by haywire immune system eating brain connections CRISPR Stopping CRISPR's genome-editing scissors from snipping out of control CRISPR patent hearing produces no clear winner, only 'soft signals ' Did a Swedish researcher eat the first CRISPR meal ever served? Top articles in Careers dollars in a

  17. 367-AAA

    NASA Image and Video Library

    1969-11-18

    Apollo 12 Public Affairs Officer (PAO) Mission Commentary, November 17-18, 1969. This is 3.25 hours of audio covering communications occurring between 82 hours, 41 minutes into the mission, through 86 hours, 38 minutes which was on November 17, 1969, 21:03 CST until November 18, 1969, 1:00 CST. Communication is quite sparse on the recording, with large sections of silence or miscellaneous noise. Transcript of audio is available at http://www.jsc.nasa.gov/history/mission_trans/AS12_PAO.PDF, on pages 239-259 of the 979-page document.

  18. Aortic Arch Aneurysms: Treatment with Extra anatomical Bypass and Endovascular Stent-Grafting

    SciTech Connect

    Kato, Noriyuki; Shimono, Takatsugu; Hirano, Tadanori

    2002-10-15

    Endovascular repair of thoracic aortic aneurysms is emerging as an attractive alternative to surgical graft replacement. However,patients with aortic arch aneurysms are often excluded from the target of endovascular repair because of lack of suitable landing zones, especially at the proximal ones. In this paper we describe our method for treating patients with aortic arch aneurysms using a combination of extra anatomical bypass surgery and endovascular stent-grafting.

  19. Extracellular matrix scaffold as a tubular graft for ascending aorta aneurysm repair.

    PubMed

    Abu Saleh, Walid K; Al Jabbari, Odeaa; Grande-Allen, Jane; Ramchandani, Mahesh

    2015-08-01

    Although extracellular xenograft repair has produced encouraging results when applied to cardiac, valvular, and specific aortic defects, its employment as a tube graft to replace the ascending aorta has not been reported. We describe a patient who underwent resection and replacement of an infected ascending aortic graft with an extracellular matrix conduit. The patient did well, but 14 months later developed a pseudoaneurysm from the staple line used to construct the extracellular matrix conduit. The patient underwent a repeat sternotomy and removal of the graft. Because of the increased risk of graft failure, a homograft was felt to be more appropriate in this setting. Ultimately, we were unable to implant the homograft because it was too small for the aortic root; therefore we decided to construct a tubular graft from Cormatrix extracellular matrix (CorMatrix, Roswell, GA, USA). Fourteen months later, he presented with shortness of breath. Computed tomography scan revealed a 3.5 cm pseudoaneurysm of the ascending aorta. It appeared as if there was a disruption of the staple line in the extra cellular matrix graft. The plan was to replace it with a Dacron graft. The Cormatrix graft material was removed and sent for culture and histological analysis. A 28-mm Gel weave graft (Terumo Cardiovascular Systems, Ann Arbor, MI, USA) was implanted. The patient tolerated the procedure well with good hemodynamics. Our experience suggests that the superior strength, handling characteristics, and resistance to infection make extra cellular matrix scaffold a possible alternative conduit to cryopreserved homografts. Applicability as an aortic conduit merits further investigation to better understand behavior of extra cellular matrix in this situation. © 2015 Wiley Periodicals, Inc.

  20. The Abdominal Aortic Aneurysm Statistically Corrected Operative Risk Evaluation (AAA SCORE) for predicting mortality after open and endovascular interventions.

    PubMed

    Ambler, Graeme K; Gohel, Manjit S; Mitchell, David C; Loftus, Ian M; Boyle, Jonathan R

    2015-01-01

    Accurate adjustment of surgical outcome data for risk is vital in an era of surgeon-level reporting. Current risk prediction models for abdominal aortic aneurysm (AAA) repair are suboptimal. We aimed to develop a reliable risk model for in-hospital mortality after intervention for AAA, using rigorous contemporary statistical techniques to handle missing data. Using data collected during a 15-month period in the United Kingdom National Vascular Database, we applied multiple imputation methodology together with stepwise model selection to generate preoperative and perioperative models of in-hospital mortality after AAA repair, using two thirds of the available data. Model performance was then assessed on the remaining third of the data by receiver operating characteristic curve analysis and compared with existing risk prediction models. Model calibration was assessed by Hosmer-Lemeshow analysis. A total of 8088 AAA repair operations were recorded in the National Vascular Database during the study period, of which 5870 (72.6%) were elective procedures. Both preoperative and perioperative models showed excellent discrimination, with areas under the receiver operating characteristic curve of .89 and .92, respectively. This was significantly better than any of the existing models (area under the receiver operating characteristic curve for best comparator model, .84 and .88; P < .001 and P = .001, respectively). Discrimination remained excellent when only elective procedures were considered. There was no evidence of miscalibration by Hosmer-Lemeshow analysis. We have developed accurate models to assess risk of in-hospital mortality after AAA repair. These models were carefully developed with rigorous statistical methodology and significantly outperform existing methods for both elective cases and overall AAA mortality. These models will be invaluable for both preoperative patient counseling and accurate risk adjustment of published outcome data. Copyright © 2015 Society

  1. Structure determination of disease associated peak AAA from l-Tryptophan implicated in the eosinophilia-myalgia syndrome.

    PubMed

    Klarskov, Klaus; Gagnon, Hugo; Boudreault, Pierre-Luc; Normandin, Chad; Plancq, Baptiste; Marsault, Eric; Gleich, Gerald J; Naylor, Stephen

    2018-01-05

    The eosinophilia-myalgia syndrome (EMS) outbreak of 1989 that occurred in the USA and elsewhere was caused by the ingestion of l-Tryptophan (L-Trp) solely manufactured by the Japanese company Showa Denko K.K. (SD). Six compounds present in the SD L-Trp were reported to be case-associated contaminants. However, "one" of these compounds, Peak AAA has remained structurally uncharacterized, despite the fact that it was described as "the only statistically significant (p=0.0014) contaminant". Here, we employ on-line microcapillary-high performance liquid chromatography-electrospray ionization mass spectrometry (LC-MS), and tandem mass spectrometry (MS/MS) to determine that Peak AAA is in fact two structurally related isomers. Peak AAA 1 and Peak AAA 2 differed in LC retention times, and were determined by accurate mass-LC-MS to both have a protonated molecular ion (MH +) of mass 343.239Da (Da), corresponding to a molecular formula of C 21 H 30 N 2 O 2, and possessing eight degrees of unsaturation (DoU) for the non-protonated molecule. By comparing the LC-MS and LC-MS-MS retention times and spectra with authentic synthetic standards, Peak AAA 1 was identified as the intermolecular condensation product of L-Trp with anteiso 7-methylnonanoic acid, to afford (S)-2-amino-3-(2-((S,E)-7-methylnon-1-en-1-yl)-1H-indol-3-yl)propanoic acid. Peak AAA 2 was determined to be a condensation product of L-Trp with decanoic acid, which produced (S)-2-amino-3-(2-((E)-dec-1-en-1-yl)-1H-indol-3-yl)propanoic acid. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Structural dynamics of the MecA-ClpC complex: a type II AAA+ protein unfolding machine.

    PubMed

    Liu, Jing; Mei, Ziqing; Li, Ningning; Qi, Yutao; Xu, Yanji; Shi, Yigong; Wang, Feng; Lei, Jianlin; Gao, Ning

    2013-06-14

    The MecA-ClpC complex is a bacterial type II AAA(+) molecular machine responsible for regulated unfolding of substrates, such as transcription factors ComK and ComS, and targeting them to ClpP for degradation. The six subunits of the MecA-ClpC complex form a closed barrel-like structure, featured with three stacked rings and a hollow passage, where substrates are threaded and translocated through successive pores. Although the general concepts of how polypeptides are unfolded and translocated by internal pore loops of AAA(+) proteins have long been conceived, the detailed mechanistic model remains elusive. With cryoelectron microscopy, we captured four different structures of the MecA-ClpC complexes. These complexes differ in the nucleotide binding states of the two AAA(+) rings and therefore might presumably reflect distinctive, representative snapshots from a dynamic unfolding cycle of this hexameric complex. Structural analysis reveals that nucleotide binding and hydrolysis modulate the hexameric complex in a number of ways, including the opening of the N-terminal ring, the axial and radial positions of pore loops, the compactness of the C-terminal ring, as well as the relative rotation between the two nucleotide-binding domain rings. More importantly, our structural and biochemical data indicate there is an active allosteric communication between the two AAA(+) rings and suggest that concerted actions of the two AAA(+) rings are required for the efficiency of the substrate unfolding and translocation. These findings provide important mechanistic insights into the dynamic cycle of the MecA-ClpC unfoldase and especially lay a foundation toward the complete understanding of the structural dynamics of the general type II AAA(+) hexamers.

  3. Evaluation of alginate dialdehyde cross-linked gelatin hydrogel as a biodegradable sealant for polyester vascular graft.

    PubMed

    Manju, Saraswathy; Muraleedharan, Chirathodi Vayalappil; Rajeev, Adathala; Jayakrishnan, Attipettah; Joseph, Roy

    2011-07-01

    Vascular grafts are devices intended to replace compromised arteries in the body and grafts made of polyethylene terephthalate (PET) fabric have been used mainly for synthetic grafting procedures involving medium to large diameter vascular grafts. Though porosity of the graft permits tissue in-growth, it would lead to bleeding through the graft walls immediately after implantation. So it is essential to seal the pores either by preclotting with patient's own blood or by other sealing materials prior to implantation in order to prevent blood leakage through the graft wall. Biodegradable hydrogel materials are ideal candidates for this purpose. Apart from sealing the pores, they offer biocompatible and low-thrombogenic surfaces when coated on vascular graft. In the present study, a biodegradable hydrogel, derived from oxidized alginate and gelatin, has been deposited on PET grafts by dip coating and were characterized for its efficacy on sealing the pores of the graft. Water permeability in the static and pulsatile conditions, burst strength, in vitro cell culture cytotoxicity, hemocompatibility, and endothelial cell adhesion and proliferation of the coated grafts were investigated. Results showed that the alginate dialdehyde cross-linked gelatin hydrogel was nontoxic, hemocompatible, and was efficient in sealing the pores of the graft. Blood perfusion study showed that when hydrogel-coated grafts were exposed to blood for 30 min, they showed little affinity toward platelets or leukocytes. Hemolytic potential of PET was significantly reduced when it was coated with hydrogel. Improved adhesion and proliferation of endothelial cells were observed when PET grafts were coated with hydrogel. Results also showed that coating with hydrogel did not affect the burst strength of the PET graft. Copyright © 2011 Wiley Periodicals, Inc.

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

    PubMed

    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.

  5. OGLE16aaa - a signature of a hungry supermassive black hole

    NASA Astrophysics Data System (ADS)

    Wyrzykowski, Łukasz; Zieliński, M.; Kostrzewa-Rutkowska, Z.; Hamanowicz, A.; Jonker, P. G.; Arcavi, I.; Guillochon, J.; Brown, P. J.; Kozłowski, S.; Udalski, A.; Szymański, M. K.; Soszyński, I.; Poleski, R.; Pietrukowicz, P.; Skowron, J.; Mróz, P.; Ulaczyk, K.; Pawlak, M.; Rybicki, K. A.; Greiner, J.; Krühler, T.; Bolmer, J.; Smartt, S. J.; Maguire, K.; Smith, K.

    2017-02-01

    We present the discovery and first three months of follow-up observations of a currently on-going unusual transient detected by the Optical Gravitational Lensing Experiment (OGLE-IV) survey, located in the centre of a galaxy at redshift z = 0.1655. The long rise to absolute magnitude of -20.5 mag, slow decline, very broad He and H spectral features make OGLE16aaa similar to other optical/UV tidal disruption events (TDEs). Weak narrow emission lines in the spectrum and archival photometric observations suggest the host galaxy is a weak-line active galactic nucleus, which has been accreting at higher rate in the past. OGLE16aaa, along with SDSS J0748, seems to form a sub-class of TDEs by weakly or recently active supermassive black holes (SMBHs). This class might bridge the TDEs by quiescent SMBHs and flares observed as `changing-look quasars', if we interpret the latter as TDEs. If this picture is true, the previously applied requirement for identifying a flare as a TDE that it had to come from an inactive nucleus, could be leading to observational bias in TDE selection, thus affecting TDE-rate estimations.

  6. Structural basis of protein translocation by the Vps4-Vta1 AAA ATPase

    PubMed Central

    Monroe, Nicole; Han, Han; Shen, Peter S; Sundquist, Wesley I; Hill, Christopher P

    2017-01-01

    Many important cellular membrane fission reactions are driven by ESCRT pathways, which culminate in disassembly of ESCRT-III polymers by the AAA ATPase Vps4. We report a 4.3 Å resolution cryo-EM structure of the active Vps4 hexamer with its cofactor Vta1, ADP·BeFx, and an ESCRT-III substrate peptide. Four Vps4 subunits form a helix whose interfaces are consistent with ATP binding, is stabilized by Vta1, and binds the substrate peptide. The fifth subunit approximately continues this helix but appears to be dissociating. The final Vps4 subunit completes a notched-washer configuration as if transitioning between the ends of the helix. We propose that ATP binding propagates growth at one end of the helix while hydrolysis promotes disassembly at the other end, so that Vps4 ‘walks’ along ESCRT-III until it encounters the ordered N-terminal domain to destabilize the ESCRT-III lattice. This model may be generally applicable to other protein-translocating AAA ATPases. DOI: http://dx.doi.org/10.7554/eLife.24487.001 PMID:28379137

  7. Mechanism of the AAA+ ATPases pontin and reptin in the biogenesis of H/ACA RNPs.

    PubMed

    Machado-Pinilla, Rosario; Liger, Dominique; Leulliot, Nicolas; Meier, U Thomas

    2012-10-01

    The AAA+ ATPases pontin and reptin function in a staggering array of cellular processes including chromatin remodeling, transcriptional regulation, DNA damage repair, and assembly of macromolecular complexes, such as RNA polymerase II and small nucleolar (sno) RNPs. However, the molecular mechanism for all of these AAA+ ATPase associated activities is unknown. Here we document that, during the biogenesis of H/ACA RNPs (including telomerase), the assembly factor SHQ1 holds the pseudouridine synthase NAP57/dyskerin in a viselike grip, and that pontin and reptin (as components of the R2TP complex) are required to pry NAP57 from SHQ1. Significantly, the NAP57 domain captured by SHQ1 harbors most mutations underlying X-linked dyskeratosis congenita (X-DC) implicating the interface between the two proteins as a target of this bone marrow failure syndrome. Homing in on the essential first steps of H/ACA RNP biogenesis, our findings provide the first insight into the mechanism of action of pontin and reptin in the assembly of macromolecular complexes.

  8. Mechanism of the AAA+ ATPases pontin and reptin in the biogenesis of H/ACA RNPs

    PubMed Central

    Machado-Pinilla, Rosario; Liger, Dominique; Leulliot, Nicolas; Meier, U. Thomas

    2012-01-01

    The AAA+ ATPases pontin and reptin function in a staggering array of cellular processes including chromatin remodeling, transcriptional regulation, DNA damage repair, and assembly of macromolecular complexes, such as RNA polymerase II and small nucleolar (sno) RNPs. However, the molecular mechanism for all of these AAA+ ATPase associated activities is unknown. Here we document that, during the biogenesis of H/ACA RNPs (including telomerase), the assembly factor SHQ1 holds the pseudouridine synthase NAP57/dyskerin in a viselike grip, and that pontin and reptin (as components of the R2TP complex) are required to pry NAP57 from SHQ1. Significantly, the NAP57 domain captured by SHQ1 harbors most mutations underlying X-linked dyskeratosis congenita (X-DC) implicating the interface between the two proteins as a target of this bone marrow failure syndrome. Homing in on the essential first steps of H/ACA RNP biogenesis, our findings provide the first insight into the mechanism of action of pontin and reptin in the assembly of macromolecular complexes. PMID:22923768

  9. Inflammatory cell phenotypes in AAAs; their role and potential as targets for therapy

    PubMed Central

    Dale, Matthew A; Ruhlman, Melissa K.; Baxter, B. Timothy

    2015-01-01

    Abdominal aortic aneurysms are characterized by chronic inflammatory cell infiltration. AAA is typically an asymptomatic disease and caused approximately 15,000 deaths annually in the U.S. Previous studies have examined both human and murine aortic tissue for the presence of various inflammatory cell types. Studies show that in both human and experimental AAAs, prominent inflammatory cell infiltration, such as CD4+ T cells and macrophages, occurs in the damaged aortic wall. These cells have the ability to undergo phenotypic modulation based on microenvironmental cues, potentially influencing disease progression. Pro-inflammatory CD4+ T cells and classically activated macrophages dominate the landscape of aortic infiltrates. The skew to pro-inflammatory phenotypes alters disease progression and plays a role in causing chronic inflammation. The local cytokine production and presence of inflammatory mediators, such as extracellular matrix breakdown products, influence the uneven balance of the inflammatory infiltrate phenotypes. Understanding and developing new strategies that target the pro-inflammatory phenotype could provide useful therapeutic targets for a disease with no current pharmacological intervention. PMID:26044582

  10. TRIP13 is a protein-remodeling AAA+ ATPase that catalyzes MAD2 conformation switching

    DOE PAGES

    Ye, Qiaozhen; Rosenberg, Scott C.; Moeller, Arne; ...

    2015-04-28

    The AAA+ family ATPase TRIP13 is a key regulator of meiotic recombination and the spindle assembly checkpoint, acting on signaling proteins of the conserved HORMA domain family. Here we present the structure of the Caenorhabditis elegans TRIP13 ortholog PCH-2, revealing a new family of AAA+ ATPase protein remodelers. PCH-2 possesses a substrate-recognition domain related to those of the protein remodelers NSF and p97, while its overall hexameric architecture and likely structural mechanism bear close similarities to the bacterial protein unfoldase ClpX. We find that TRIP13, aided by the adapter protein p31(comet), converts the HORMA-family spindle checkpoint protein MAD2 from amore » signaling-active ‘closed’ conformer to an inactive ‘open’ conformer. We propose that TRIP13 and p31(comet) collaborate to inactivate the spindle assembly checkpoint through MAD2 conformational conversion and disassembly of mitotic checkpoint complexes. A parallel HORMA protein disassembly activity likely underlies TRIP13's critical regulatory functions in meiotic chromosome structure and recombination.« less

  11. A Migrated Aortic Stent Graft Causing Erosive Spondylopathy

    SciTech Connect

    Gestrich, Christopher, E-mail: christopher.gestrich@ukb.uni-bonn.de; Probst, Chris, E-mail: chris.probst@ukb.uni-bonn.de; Wilhelm, Kai, E-mail: kai.wilhelm@ek-bonn.de

    We report about a patient presenting with back pain 4 months after an uneventful endovascular implantation of an aortic stent graft. Computed tomography scan revealed a migration of the stent with consecutive endoleakage, kink formation, and movement of the stent toward the spine, which caused destruction of the aortic wall as well as vertebral necrosis. Explantation of the stent and replacement of the native aorta relieved the patient of his symptoms.

  12. Aortic valve replacement in octogenarians.

    PubMed

    Bose, Amal K; Aitchison, James D; Dark, John H

    2007-07-13

    As our population ages and life expectancy increases the number of people aged over 80 and more referred for cardiac surgery is growing. This study sought to identify the outcome of aortic valve replacement (AVR) in octogenarians. 68 patients aged 80 years or more underwent AVR at the Freeman Hospital, between April 2001 and April 2004. A retrospective review of the notes and outcomes from the patients' GP and the NHS strategic tracking service was performed. 54% (37) underwent isolated AVR whilst 46% (31) underwent combined AVR and CABG. Follow up was 100% complete. The mean age was 83.1 +/- s.d. 2.9 years, a mean gradient of 83 +/- s.d. 31 mmHg and mean AVA of 0.56 cm2. The mean additive EuroSCORE was 8.6 +/- s.d. 1.2, the logistic EuroSCORE mean 12.0 +/- s.d. 5.9. In hospital 30 day mortality was 13 %. Survival was 80% at 1 year and 78% at 2 years. Median follow up was for 712 days. Stepwise logistic regression identified chronic obstructive airways disease as an independent predictor of mortality (p < 0.05). Survival was not adversely affected by the addition of coronary artery bypass grafts to aortic valve replacement, the presence of peripheral vascular disease, hypertension or diabetes. In this study duration of cross clamp or bypass time were not found to reach significance as independent predictors of mortality. Our study demonstrates that the operative mortality for AVR in the over eighties is good, whilst the mid to long term outcome is excellent There is a very low attrition rate with those undergoing the procedure living as long than their age matched population. This study confirms AVR is a safe, acceptable treatment for octogenarians with excellent mid term outcomes.

  13. Crystal Structure and Biochemical Characterization of a Mycobacterium smegmatis AAA-Type Nucleoside Triphosphatase Phosphohydrolase (Msm0858).

    PubMed

    Unciuleac, Mihaela-Carmen; Smith, Paul C; Shuman, Stewart

    2016-05-15

    AAA proteins (ATPases associated with various cellular activities) use the energy of ATP hydrolysis to drive conformational changes in diverse macromolecular targets. Here, we report the biochemical characterization and 2.5-Å crystal structure of a Mycobacterium smegmatis AAA protein Msm0858, the ortholog of Mycobacterium tuberculosis Rv0435c. Msm0858 is a magnesium-dependent ATPase and is active with all nucleoside triphosphates (NTPs) and deoxynucleoside triphosphates (dNTPs) as substrates. The Msm0858 structure comprises (i) an N-terminal domain (amino acids [aa] 17 to 201) composed of two β-barrel modules and (ii) two AAA domains, D1 (aa 212 to 473) and D2 (aa 476 to 744), each of which has ADP in the active site. Msm0858-ADP is a monomer in solution and in crystallized form. Msm0858 domains are structurally homologous to the corresponding modules of mammalian p97. However, the position of the N-domain modules relative to the AAA domains in the Msm0858-ADP tertiary structure is different and would impede the formation of a p97-like hexameric quaternary structure. Mutational analysis of the A-box and B-box motifs indicated that the D1 and D2 AAA domains are both capable of ATP hydrolysis. Simultaneous mutations of the D1 and D2 active-site motifs were required to abolish ATPase activity. ATPase activity was effaced by mutation of the putative D2 arginine finger, suggesting that Msm0858 might oligomerize during the ATPase reaction cycle. A truncated variant Msm0858 (aa 212 to 745) that lacks the N domain was characterized as a catalytically active homodimer. Recent studies have underscored the importance of AAA proteins (ATPases associated with various cellular activities) in the physiology of mycobacteria. This study reports the ATPase activity and crystal structure of a previously uncharacterized mycobacterial AAA protein, Msm0858. Msm0858 consists of an N-terminal β-barrel domain and two AAA domains, each with ADP bound in the active site. Msm0858 is a

  14. Introducing AAA-MS, a rapid and sensitive method for amino acid analysis using isotope dilution and high-resolution mass spectrometry.

    PubMed

    Louwagie, Mathilde; Kieffer-Jaquinod, Sylvie; Dupierris, Véronique; Couté, Yohann; Bruley, Christophe; Garin, Jérôme; Dupuis, Alain; Jaquinod, Michel; Brun, Virginie

    2012-07-06

    Accurate quantification of pure peptides and proteins is essential for biotechnology, clinical chemistry, proteomics, and systems biology. The reference method to quantify peptides and proteins is amino acid analysis (AAA). This consists of an acidic hydrolysis followed by chromatographic separation and spectrophotometric detection of amino acids. Although widely used, this method displays some limitations, in particular the need for large amounts of starting material. Driven by the need to quantify isotope-dilution standards used for absolute quantitative proteomics, particularly stable isotope-labeled (SIL) peptides and PSAQ proteins, we developed a new AAA assay (AAA-MS). This method requires neither derivatization nor chromatographic separation of amino acids. It is based on rapid microwave-assisted acidic hydrolysis followed by high-resolution mass spectrometry analysis of amino acids. Quantification is performed by comparing MS signals from labeled amino acids (SIL peptide- and PSAQ-derived) with those of unlabeled amino acids originating from co-hydrolyzed NIST standard reference materials. For both SIL peptides and PSAQ standards, AAA-MS quantification results were consistent with classical AAA measurements. Compared to AAA assay, AAA-MS was much faster and was 100-fold more sensitive for peptide and protein quantification. Finally, thanks to the development of a labeled protein standard, we also extended AAA-MS analysis to the quantification of unlabeled proteins.

  15. Radionuclide evaluation of free vascularized bone graft viability. [/sup 99m/Tc-methylene diphosphonate

    SciTech Connect

    Lisbona, R.; Rennie, W.R.J.; Daniel, R.K.

    1980-02-01

    Free vascularized bone grafting is a new technique applied to the reconstructive surgery of long bones affected by aggressive benign or malignant processes, as well as traumatic deficiencies. These bone lesions may be treated by en bloc excision and replacement with fibular segments or osteocutaneous flaps from the groin isolated on their vascular pedicle. Microvascular anastomosis of the pedicle at the recipient site is necessary. Radionuclide bone imaging is unique in the assessment of the free vascularized bone graft because postoperative graft uptake of radiopharmaceutical reflects patent anastomoses and segmental bone viability.

  16. Polyether/Polyester Graft Copolymers

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

  17. Skin grafts: a rural general surgical perspective.

    PubMed

    Henderson, Nigel J; Fancourt, Michael; Gilkison, William; Kyle, Stephen; Mosquera, Damien

    2009-05-01

    Skin grafts are a common method of closing skin defects. The literature comparing methods of graft application and subsequent outcomes is poor, but reports indicate a graft failure rate between 2 and 30%. The aim of this study was to audit our current skin graft practice. Data were collected prospectively on all skin grafts performed by the general surgical department between 1st December 2005 and 1st December 2006. A standardized proforma on each patient included data on age, gender, graft indication, application method, comorbidities, length of stay, and graft outcomes including graft take at 1, 2 and 6 weeks post-operatively. There were 85 grafts performed on 74 patients, median age 72 years (9-102 years), with 10 (12%) acute admissions. Prophylactic antibiotics were given to 50% (38 of 74) of patients. Successful grafts (>80% take) were performed in 68 (80%) patients. The overall graft complication rate was 24.7% (22 of 85 grafts). Infection occurred in 13 of 17 graft failures. No patients underwent re-operation for graft failure. Patients who received prophylactic antibiotics had a reduced risk of graft failure (Fisher's exact test, P = 0.016). Skin grafts were performed successfully in the majority of patients. Graft complication and failure rates compare well with the world literature. The use of prophylactic antibiotics was the only predictor of successful graft take.

  18. A Non-Competitive Inhibitor of VCP/p97 and VPS4 Reveals Conserved Allosteric Circuits in Type I and II AAA ATPases.

    PubMed

    Pöhler, Robert; Krahn, Jan H; van den Boom, Johannes; Dobrynin, Grzegorz; Kaschani, Farnusch; Eggenweiler, Hans-Michael; Zenke, Frank T; Kaiser, Markus; Meyer, Hemmo

    2018-02-05

    AAA ATPases have pivotal functions in diverse cellular processes essential for survival and proliferation. Revealing strategies for chemical inhibition of this class of enzymes is therefore of great interest for the development of novel chemotherapies or chemical tools. Here, we characterize the compound MSC1094308 as a reversible, allosteric inhibitor of the type II AAA ATPase human ubiquitin-directed unfoldase (VCP)/p97 and the type I AAA ATPase VPS4B. Subsequent proteomic, genetic and biochemical studies indicate that MSC1094308 binds to a previously characterized drugable hotspot of p97, thereby inhibiting the D2 ATPase activity. Our results furthermore indicate that a similar allosteric site exists in VPS4B, suggesting conserved allosteric circuits and drugable sites in both type I and II AAA ATPases. Our results may thus guide future chemical tool and drug discovery efforts for the biomedically relevant AAA ATPases. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Coralline hydroxyapatite bone graft substitutes.

    PubMed

    Elsinger, E C; Leal, L

    1996-01-01

    The authors present a review of the various bone grafts currently available with special attention to coral bone grafts. Several of the benefits of coralline hydroxyapatite bone graft substitutes, such as safety and biocompatibility, will be addressed in this article, part of an ongoing investigation of coral bone grafts used in triple arthrodesis procedures. To date, eight cases have been performed. In seven cases, granular chips were employed to pack the subtalar joint. The final case, presented in this article, represents a 26-year-old male who, 2 years previously, sustained a calcaneal fracture with resultant shortening along the lateral column. A coralline hydroxyapatite block was used at the calcaneocuboid joint to achieve distraction. Clinically, the patient is progressing well at 10 months postoperatively. Radiographically, one can still clearly appreciate the margins of the bone graft at 5 months.

  20. Grinding and polishing instead of sectioning for the tissue samples with a graft: Implications for light and electron microscopy.

    PubMed

    Mukhamadiyarov, Rinat A; Sevostyanova, Victoria V; Shishkova, Daria K; Nokhrin, Andrey V; Sidorova, Olga D; Kutikhin, Anton G

    2016-06-01

    A broad use of the graft replacement requires a detailed investigation of the host-graft interaction, including both histological examination and electron microscopy. A high quality sectioning of the host tissue with a graft seems to be complicated; in addition, it is difficult to examine the same tissue area by both of the mentioned microscopy techniques. To solve these problems, we developed a new technique of epoxy resin embedding with the further grinding, polishing, and staining. Graft-containing tissues prepared by grinding and polishing preserved their structure; however, sectioning frequently required the explantation of the graft and led to tissue disintegration. Moreover, stained samples prepared by grinding and polishing may then be assessed by both light microscopy and backscattered scanning electron microscopy. Therefore, grinding and polishing outperform sectioning when applied to the tissues with a graft. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Knee Replacement - Multiple Languages

    MedlinePlus

    ... in a new window. Arabic (العربية) Expand Section Total Knee Replacement - العربية (Arabic) Bilingual PDF Health Information Translations Chinese, Simplified (Mandarin dialect) (简体中文) Expand Section Total Knee Replacement - 简体中文 (Chinese, Simplified (Mandarin dialect)) Bilingual PDF Health ...

  2. MDCA Needle 1 Replacement

    NASA Image and Video Library

    2013-04-22

    ISS035-E-025557(22 April 2013) ---Multi-user Droplet Combustion Apparatus (MDCA) Hardware Replacement: Cassidy accessed the Combustion Integration Rack (CIR) Combustion Chamber and removed the MDCA Chamber Insert Assembly (CIA). He then replaced the MDCA Needle 1 due to a fuel line that was damaged during previous activities when the MDCA CIA was being removed from the Combustion Chamber.

  3. Detection of thoracic aortic prosthetic graft infection with 18F-fluorodeoxyglucose positron emission tomography/computed tomography.

    PubMed

    Tokuda, Yoshiyuki; Oshima, Hideki; Araki, Yoshimori; Narita, Yuji; Mutsuga, Masato; Kato, Katsuhiko; Usui, Akihiko

    2013-06-01

    To investigate the diagnostic value of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in detecting thoracic aortic prosthetic graft infection. Nine patients with clinically suspected thoracic aortic graft infection underwent FDG-PET/CT scanning. In these patients, the diagnoses could not be confirmed using conventional modalities. The patients' clinical courses were retrospectively reviewed. On the basis of surgical, microbiological and clinical follow-up findings, the aortic grafts were considered infected in 4 patients and not infected in 5. All 4 patients with graft infection (root: 2 cases, arch: 1 case and descending: 1 case) eventually underwent in situ re-replacement. Two of the 4 patients also had abdominal grafts; however, only the thoracic grafts were replaced because uptake was low around the abdominal grafts. The maximal standardized uptake value (SUVmax) in the perigraft area was higher in the infected group than in the non-infected group (11.4 ± 4.5 vs 6.9 ± 6.4), although the difference was not statistically significant. According to the receiver operating characteristic analysis, SUVmax >8 appeared to be the cut-off value in distinguishing the two groups (sensitivity: 1.0 and specificity: 0.8). FDG-PET/CT is useful for confirming the presence of graft infection by detecting high uptake around grafts and excluding other causes of inflammation. An SUVmax value greater than 8 around a graft suggests the presence of graft infection. In addition, FDG-PET/CT can be used to clarify the precise extent of infection. This is especially useful if multiple separated prosthetic grafts have been implanted.

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

    SciTech Connect

    Letocart, Vincent, E-mail: vincent.letocart@chu-nantes.fr; Fau, Georges, E-mail: georges.fau@chu-nantes.fr; Tirouvanziam, Ashok, E-mail: ashok.tirouvanziam@chu-nantes.fr

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

  5. Student-Athlete Perceptions of a Summer Pre-Enrollment Experience at an NCAA Division I-AAA Institution

    ERIC Educational Resources Information Center

    Dalgety, Michael Franklin

    2012-01-01

    The purpose of this exploratory qualitative study was to examine student-athlete perceptions of the role of summer pre-enrollment in their adjustment and transition to college. The study focused on student-athletes who received athletically-related financial aid at a National Collegiate Athletic Association (NCAA) Division I-AAA institution. The…

  6. Deviation of the typical AAA substrate-threading pore prevents fatal protein degradation in yeast Cdc48.

    PubMed

    Esaki, Masatoshi; Islam, Md Tanvir; Tani, Naoki; Ogura, Teru

    2017-07-14

    Yeast Cdc48 is a well-conserved, essential chaperone of ATPases associated with diverse cellular activity (AAA) proteins, which recognizes substrate proteins and modulates their conformations to carry out many cellular processes. However, the fundamental mechanisms underlying the diverse pivotal roles of Cdc48 remain unknown. Almost all AAA proteins form a ring-shaped structure with a conserved aromatic amino acid residue that is essential for proper function. The threading mechanism hypothesis suggests that this residue guides the intrusion of substrate proteins into a narrow pore of the AAA ring, thereby becoming unfolded. By contrast, the aromatic residue in one of the two AAA rings of Cdc48 has been eliminated through evolution. Here, we show that artificial retrieval of this aromatic residue in Cdc48 is lethal, and essential features to support the threading mechanism are required to exhibit the lethal phenotype. In particular, genetic and biochemical analyses of the Cdc48 lethal mutant strongly suggested that when in complex with the 20S proteasome, essential proteins are abnormally forced to thread through the Cdc48 pore to become degraded, which was not detected in wild-type Cdc48. Thus, the widely applicable threading model is less effective for wild-type Cdc48; rather, Cdc48 might function predominantly through an as-yet-undetermined mechanism.

  7. McArthur removes AAA clamps and ducts inside the CHeCS Rack during Expedition 12

    NASA Image and Video Library

    2005-12-09

    ISS012-E-10817 (9 December 2005) --- Astronaut William S. (Bill) McArthur Jr., Expedition 12 commander and NASA space station science officer, opens the back panel of the Crew Health Care System (CHeCS) rack and removes the Avionics Air Assembly (AAA) air ducts during in-flight maintenance (IFM) in the Destiny laboratory of the International Space Station.

  8. In response to an open invitation for comments on AAAS project 2061's Benchmark books on science. Part 1: documentation of serious errors in cell biology.

    PubMed

    Ling, Gilbert

    2006-01-01

    Project 2061 was founded by the American Association for the Advancement of Science (AAAS) to improve secondary school science education. An in-depth study of ten 9 to 12th grade biology textbooks led to the verdict that none conveyed "Big Ideas" that would give coherence and meaning to the profusion of lavishly illustrated isolated details. However, neither the Project report itself nor the Benchmark books put out earlier by the Project carries what deserves the designation of "Big Ideas." Worse, in the two earliest-published Benchmark books, the basic unit of all life forms--the living cell--is described as a soup enclosed by a cell membrane, that determines what can enter or leave the cell. This is astonishing since extensive experimental evidence has unequivocally disproved this idea 60 years ago. A "new" version of the membrane theory brought in to replace the discredited (sieve) version is the pump model--currently taught as established truth in all high-school and college biology textbooks--was also unequivocally disproved 40 years ago. This comment is written partly in response to Bechmark's gracious open invitation for ideas to improve the books and through them, to improve US secondary school science education.

  9. Re-do aortic root replacement after an allograft aortic root replacement.

    PubMed

    Vrtik, Marian; Tesar, Peter J

    2009-10-01

    Structural degeneration of allograft aortic root is a global process. In addition to valvular degeneration, the allograft wall calcification poses a risk of systemic calcific embolization and late phase anastomotic aneurysm formation and rupture (anecdotal). Furthermore, the valve annulus is often small, and the tissues are rigid making the implantation of an adequately sized prosthesis within the allograft wall difficult. To avoid these issues, we routinely perform re-do aortic root replacement with either a mechanical valve conduit or bio-root composite graft. The technique has been successfully used in 22 consecutive patients with no operative mortality and minimal morbidity.

  10. SMYD2 promoter DNA methylation is associated with abdominal aortic aneurysm (AAA) and SMYD2 expression in vascular smooth muscle cells.

    PubMed

    Toghill, Bradley J; Saratzis, Athanasios; Freeman, Peter J; Sylvius, Nicolas; Bown, Matthew J

    2018-01-01

    Abdominal aortic aneurysm (AAA) is a deadly cardiovascular disease characterised by the gradual, irreversible dilation of the abdominal aorta. AAA is a complex genetic disease but little is known about the role of epigenetics. Our objective was to determine if global DNA methylation and CpG-specific methylation at known AAA risk loci is associated with AAA, and the functional effects of methylation changes. We assessed global methylation in peripheral blood mononuclear cell DNA from 92 individuals with AAA and 93 controls using enzyme-linked immunosorbent assays, identifying hyper-methylation in those with large AAA and a positive linear association with AAA diameter ( P  < 0.0001, R 2  = 0.3175).We then determined CpG methylation status of regulatory regions in genes located at AAA risk loci identified in genome-wide association studies, using bisulphite next-generation sequencing (NGS) in vascular smooth muscle cells (VSMCs) taken from aortic tissues of 44 individuals (24 AAAs and 20 controls). In IL6R , 2 CpGs were hyper-methylated ( P  = 0.0145); in ERG , 13 CpGs were hyper-methylated ( P  = 0.0005); in SERPINB9 , 6 CpGs were hypo-methylated ( P  = 0.0037) and 1 CpG was hyper-methylated ( P  = 0.0098); and in SMYD2 , 4 CpGs were hypo-methylated ( P  = 0.0012).RT-qPCR was performed for each differentially methylated gene on mRNA from the same VSMCs and compared with methylation. This analysis revealed downregulation of SMYD2 and SERPINB9 in AAA, and a direct linear relationship between SMYD2 promoter methylation and SMYD2 expression ( P  = 0.038). Furthermore, downregulation of SMYD2 at the site of aneurysm in the aortic wall was further corroborated in 6 of the same samples used for methylation and gene expression analysis with immunohistochemistry. This study is the first to assess DNA methylation in VSMCs from individuals with AAA using NGS, and provides further evidence there is an epigenetic basis to AAA. Our study shows that

  11. [Incidence and risk factors of ischemic colitis after AAA repair in our cohort of patients from 2005 through 2009].

    PubMed

    Biros, E; Staffa, R

    2011-12-01

    Using retrospective analysis, we sought to investigate the incidence, risk factors and therapeutic outcomes of ischemic colitis in patients after surgical and endovascular repair of abdominal aortic aneurysms (AAA). The complete inpatient and outpatient medical records of all patients undergoing surgical or endovascular AAA repair in our Department from January 2005 to December 2009 were retrospectively reviewed. We selected all patients who had developed an acute or chronic form of postoperative large or small bowel ischemia. We carried out data analysis and focused on determining the incidence and risk factors of this complication and the outcomes of its treatment. Two hundred and seven AAA repairs were performed in the 2nd Department of Surgery of St. Anne's University Hospital in Brno and the Faculty of Medicine of Masaryk University in Brno during the studied period. This number includes endovascular AAA repairs (13 patients; 6.3%) as well as one robot-assisted operation, and also the whole clinical spectrum of AAA manifestations, from non-symptomatic forms to ruptured aneurysm forms. The rest of the patients underwent open operation. Bowel ischemia developed in a total of 11 patients (5.3 %), who all underwent open AAA repair. Six of these patients presented with non-ruptured AAA and the remaining 5 with ruptured AAA. In 3 patients, bowel ischemia was diagnosed with a delay of several months from the original revascularization operation in the clinical form of postischemic stricture of the large bowel (2 patients) or postischemic colitis (1 patient). 8 patients were diagnosed with acute ischemic colitis affecting an isolated segment of the small bowel in one patient, extended segments of the large bowel (descending colon + sigmoid colon + rectum) in 2 patients, and typically the descending and sigmoid colon in 5 patients. None of the three patients with late manifestation of ischemic colitis died. Of the 8 patients with acute presentation, resection of the

  12. Integrated regulation of PIKK-mediated stress responses by AAA+ proteins RUVBL1 and RUVBL2

    PubMed Central

    Izumi, Natsuko; Yamashita, Akio; Ohno, Shigeo

    2012-01-01

    Proteins of the phosphatidylinositol 3-kinase-related protein kinase (PIKK) family are activated by various cellular stresses, including DNA damage, premature termination codon and nutritional status, and induce appropriate cellular responses. The importance of PIKK functions in the maintenance of genome integrity, accurate gene expression and the proper control of cell growth/proliferation is established. Recently, ATPase associated diverse cellular activities (AAA+) proteins RUVBL1 and RUVBL2 (RUVBL1/2) have been shown to be common regulators of PIKKs. The RUVBL1/2 complex regulates PIKK-mediated stress responses through physical interactions with PIKKs and by controlling PIKK mRNA levels. In this review, the functions of PIKKs in stress responses are outlined and the physiological significance of the integrated regulation of PIKKs by the RUVBL1/2 complex is presented. We also discuss a putative “PIKK regulatory chaperone complex” including other PIKK regulators, Hsp90 and the Tel2 complex. PMID:22540023

  13. Characterisation of pectins extracted from banana peels (Musa AAA) under different conditions using an experimental design.

    PubMed

    Happi Emaga, Thomas; Ronkart, Sébastien N; Robert, Christelle; Wathelet, Bernard; Paquot, Michel

    2008-05-15

    An experimental design was used to study the influence of pH (1.5 and 2.0), temperature (80 and 90°C) and time (1 and 4h) on extraction of pectin from banana peels (Musa AAA). Yield of extracted pectins, their composition (neutral sugars, galacturonic acid, and degree of esterification) and some macromolecular characteristics (average molecular weight, intrinsic viscosity) were determined. It was found that extraction pH was the most important parameter influencing yield and pectin chemical composition. Lower pH values negatively affected the galacturonic acid content of pectin, but increased the pectin yield. The values of degree of methylation decreased significantly with increasing temperature and time of extraction. The average molecular weight ranged widely from 87 to 248kDa and was mainly influenced by pH and extraction time. Copyright © 2007 Elsevier Ltd. All rights reserved.

  14. Conformational changes in the AAA ATPase p97–p47 adaptor complex

    PubMed Central

    Beuron, Fabienne; Dreveny, Ingrid; Yuan, Xuemei; Pye, Valerie E; Mckeown, Ciaran; Briggs, Louise C; Cliff, Matthew J; Kaneko, Yayoi; Wallis, Russell; Isaacson, Rivka L; Ladbury, John E; Matthews, Steve J; Kondo, Hisao; Zhang, Xiaodong; Freemont, Paul S

    2006-01-01

    The AAA+ATPase p97/VCP, helped by adaptor proteins, exerts its essential role in cellular events such as endoplasmic reticulum-associated protein degradation or the reassembly of Golgi, ER and the nuclear envelope after mitosis. Here, we report the three-dimensional cryo-electron microscopy structures at ∼20 Å resolution in two nucleotide states of the endogenous hexameric p97 in complex with a recombinant p47 trimer, one of the major p97 adaptor proteins involved in membrane fusion. Depending on the nucleotide state, we observe the p47 trimer to be in two distinct arrangements on top of the p97 hexamer. By combining the EM data with NMR and other biophysical measurements, we propose a model of ATP-dependent p97(N) domain motions that lead to a rearrangement of p47 domains, which could result in the disassembly of target protein complexes. PMID:16601695

  15. Inter-ring rotations of AAA ATPase p97 revealed by electron cryomicroscopy

    PubMed Central

    Yeung, Heidi O.; Förster, Andreas; Bebeacua, Cecilia; Niwa, Hajime; Ewens, Caroline; McKeown, Ciarán; Zhang, Xiaodong; Freemont, Paul S.

    2014-01-01

    The type II AAA+ protein p97 is involved in numerous cellular activities, including endoplasmic reticulum-associated degradation, transcription activation, membrane fusion and cell-cycle control. These activities are at least in part regulated by the ubiquitin system, in which p97 is thought to target ubiquitylated protein substrates within macromolecular complexes and assist in their extraction or disassembly. Although ATPase activity is essential for p97 function, little is known about how ATP binding or hydrolysis is coupled with p97 conformational changes and substrate remodelling. Here, we have used single-particle electron cryomicroscopy (cryo-EM) to study the effect of nucleotides on p97 conformation. We have identified conformational heterogeneity within the cryo-EM datasets from which we have resolved two major p97 conformations. A comparison of conformations reveals inter-ring rotations upon nucleotide binding and hydrolysis that may be linked to the remodelling of target protein complexes. PMID:24598262

  16. Beneficial effect of statins on total mortality in abdominal aortic aneurysm (AAA) repair.

    PubMed

    Mathisen, Sven Ross; Abdelnoor, Michael

    2017-10-01

    In this single center, retrospective cohort study we wished to compare early and total mortality for all patients treated for abdominal aortic aneurysms (AAA) with open surgery who were taking statins compared to those who were not. A cohort of 640 patients with AAA was treated with open surgery between 1999 and 2012. Patients were consecutively recruited from a source population of 390,000; 21.3% were female, and the median age was 73 years. The median follow-up was 3.93 years, with an interquartile range of 1.79-6.58 years. The total follow-up was 2855 patient-years. An explanatory strategy was used. The propensity score (PS) was implemented to control for selection bias and confounders. The crude effect of statin use showed a 78% reduction of the 30-day mortality. A stratified analysis using the Mantel-Haenszel method on quintiles of the PS gave an adjusted effect of the odds ratio equal to 0.43 (95% CI: 0.18-0.96), indicating a 57% reduction of the 30-day mortality for statin users. The adjusted rate ratio was 0.62 (95% CI: 0.45-0.83), indicating a reduction of long-term mortality of 38% for statin users compared to non-users for a median follow-up of 3.93 years. This retrospective cohort study showed a significant beneficial effect of statin use on early and long-term survival for patients treated with open surgery. To be conclusive, our results need to be replicated by a randomized clinical trial.

  17. Cartilage grafting in nasal reconstruction.

    PubMed

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

    2011-02-01

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

  18. Inheritance of graft compatibility in Douglas fir.

    Treesearch

    D.L. Copes

    1973-01-01

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

  19. Graft union formation in Douglas-fir.

    Treesearch

    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...

  20. Hip joint replacement - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100006.htm Hip joint replacement - series—Normal anatomy To use the ... to slide 5 out of 5 Overview The hip joint is made up of two major parts: ...

  1. Carbohydrates as Fat Replacers.

    PubMed

    Peng, Xingyun; Yao, Yuan

    2017-02-28

    The overconsumption of dietary fat contributes to various chronic diseases, which encourages attempts to develop and consume low-fat foods. Simple fat reduction causes quality losses that impede the acceptance of foods. Fat replacers are utilized to minimize the quality deterioration after fat reduction or removal to achieve low-calorie, low-fat claims. In this review, the forms of fats and their functions in contributing to food textural and sensory qualities are discussed in various food systems. The connections between fat reduction and quality loss are described in order to clarify the rationales of fat replacement. Carbohydrate fat replacers usually have low calorie density and provide gelling, thickening, stabilizing, and other texture-modifying properties. In this review, carbohydrates, including starches, maltodextrins, polydextrose, gums, and fibers, are discussed with regard to their interactions with other components in foods as well as their performances as fat replacers in various systems.

  2. Slab replacement maturity guidelines.

    DOT National Transportation Integrated Search

    2014-04-01

    This study investigated the use of maturity method to determine early age strength of concrete in slab : replacement application. Specific objectives were (1) to evaluate effects of various factors on the compressive : maturity-strength relationship ...

  3. Valve Repair or Replacement

    MedlinePlus

    ... called anticoagulants) for the rest of their lives. Biological valves are made from animal tissue (called a ... for valve replacement (called an autograft). Patients with biological valves usually do not need to take blood- ...

  4. Patient-reported outcomes and health status associated with chronic graft-versus-host disease.

    PubMed

    Lee, Stephanie J; Onstad, Lynn; Chow, Eric J; Shaw, Bronwen E; Jim, Heather S L; Syrjala, Karen L; Baker, K Scott; Buckley, Sarah; Flowers, Mary E

    2018-06-01

    Chronic graft-versus-host disease occurs in 20-50% of allogeneic hematopoietic cell transplantation survivors. We surveyed patients about their quality of life, symptoms, health status, comorbid conditions and medication. Instruments included the Short-Form-36 (SF-36), the Patient-Reported Outcomes Measurement Information System (PROMIS) Global and PROMIS-29 scales and the Lee Chronic Graft-versus-Host Disease Symptom Scale. Functional status was measured by self-reported Karnofsky and work status. Of 3027 surveys sent to recipients surviving one or more years after transplantation, 1377 (45%) were returned. Among these, patients reported their chronic graft-versus-host disease was mild (n=257, 18.7%), moderate (n=110, 8.0%) or severe (n=25, 1.8%). Another 377 (27.4%) never had chronic graft-versus-host disease and 280 (20.3%) had chronic graft-versus-host disease but it resolved. We excluded 328 (23.8%) who did not answer the questions about chronic graft-versus-host disease. Patients who reported moderate or severe chronic graft-versus-host disease reported worse quality of life, lower performance status, a higher symptom burden and were more likely to be taking prescription medications for pain, anxiety and depression compared to those with resolved chronic graft-versus-host disease. Self-reported measures were similar between patients with resolved chronic graft-versus-host disease and those who never had it. Our data suggest that the PROMIS measures may be able to replace the SF-36 in chronic graft-versus-host disease assessment. Between 26.7-39.4% of people with active chronic graft-versus-host disease were unable to work due to health reasons, compared with 12.1% whose chronic graft-versus-host disease had resolved and 15.4% who never had chronic graft-versus-host disease. Mouth, eye and nutrition symptoms persisted after resolution of chronic graft-versus-host disease. These results show that better prevention of and treatment for chronic graft

  5. Androgen replacement for women.

    PubMed Central

    Basson, R.

    1999-01-01

    OBJECTIVES: To determine whether a postmenopausal syndrome comprising specific changes in sexual desire and response associated with low free testosterone exists. To determine whether this syndrome is ameliorated by testosterone replacement. QUALITY OF EVIDENCE: Literature documenting that replacement of physiological levels of testosterone is beneficial and safe is scant. Only one randomized prospective blinded study examines sexual outcome in detail. MAIN MESSAGE: Testosterone is an important metabolic and sex hormone produced by the ovary throughout life. The variable reduction in ovarian testosterone production coincident with menopause is sometimes associated with a syndrome of specific changes in sexual desire and sexual response. Estrogen deficiency also impairs sexual response, but its replacement will not improve and might exacerbate sexual symptoms from androgen loss. Diagnosis of androgen deficiency is clinical, based on accurate assessment of a woman's sexual status before and after menopause and only confirmed (rather than diagnosed) by a low level of free testosterone. Partial androgen replacement restores much of the sexual response and facilitates sexual desire that is triggered by external cues. Avoiding supraphysiological levels of testosterone lessens risk of masculinization. Avoiding alkylated testosterone lessens hepatic or lipid impairment. CONCLUSION: Further prospective randomized studies of replacement of physiological levels of testosterone in women with androgen deficiency syndrome are needed, using formulations of testosterone available in Canada. The consistency of sexual changes, the associated personal and relationship distress, together with our clinical experience of the gratifying response to physiological replacement, make further studies urgently needed. PMID:10509222

  6. Synthesis and characterization of polypyrrole grafted chitin

    NASA Astrophysics Data System (ADS)

    Ramaprasad, A. T.; Latha, D.; Rao, Vijayalakshmi

    2017-05-01

    Synthesis and characterization of chitin grafted with polypyrrole (PPy) is reported in this paper. Chitin is soaked in pyrrole solution of various concentrations for different time intervals and polymerized using ammonium peroxy disulphate (APS) as an initiator. Grafting percentage of polypyrrole onto chitin is calculated from weight of chitin before and after grafting. Grafting of polymer is further verified by dissolution studies. The grafted polymer samples are characterized by FTIR, UV-Vis absorption spectrum, XRD, DSC, TGA, AFM, SEM and conductivity studies.

  7. Air Pump-Assisted Graft Centration, Graft Edge Unfolding, and Graft Uncreasing in Young Donor Graft Pre-Descemet Endothelial Keratoplasty.

    PubMed

    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.

  8. FAS grafted superhydrophobic ceramic membrane

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    Dall'Olmo, Luigi; Zanusso, Ilenia; Di Liddo, Rosa; Chioato, Tatiana; Bertalot, Thomas; Conconi, Maria Teresa

    2014-01-01

    To overcome the issues connected to the use of autologous vascular grafts and artificial materials for reconstruction of small diameter (<6 mm) blood vessels, this study aimed to develop acellular matrix- (AM-) based vascular grafts. Rat iliac arteries were decellularized by a detergent-enzymatic treatment, whereas endothelial cells (ECs) were obtained through enzymatic digestion of rat skin followed by immunomagnetic separation of CD31-positive cells. Sixteen female Lewis rats (8 weeks old) received only AM or previously in vitro reendothelialized AM as abdominal aorta interposition grafts (about 1 cm). The detergent-enzymatic treatment completely removed the cellular part of vessels and both MHC class I and class II antigens. One month after surgery, the luminal surface of implanted AMs was partially covered by ECs and several platelets adhered in the areas lacking cell coverage. Intimal hyperplasia, already detected after 1 month, increased at 3 months. On the contrary, all grafts composed by AM and ECs were completely covered at 1 month and their structure was similar to that of native vessels at 3 months. Taken together, our findings show that prostheses composed of AM preseeded with ECs could be a promising approach for the replacement of blood vessels. PMID:25136610

  10. Autologous buccal mucosa graft augmentation for foreshortened vagina.

    PubMed

    Grimsby, Gwen M; Bradshaw, Karen; Baker, Linda A

    2014-05-01

    Vaginal foreshortening after pelvic surgery or radiotherapy may lead to dyspareunia and decreased quality of life. Unfortunately, little literature exists regarding treatment options for this debilitating problem. Autologous buccal mucosal grafting has been previously reported for creation of a total neovagina and the repair of postvaginoplasty vaginal stenosis. Autologous buccal mucosa offers several advantages as a replacement material for vaginal reconstruction. Vaginal and oral buccal mucosa are both hairless, moist, nonkeratinized stratified squamous epithelia. Buccal mucosa has a dense layer of elastic fibers, imparting both elasticity and strength, and acquires a robust neovascularity with excellent graft take. The graft material is readily available and donor site scars are hidden in the mouth. A 60-year-old woman had vaginal foreshortening to 4.5 cm 15 years after radical hysterectomy and brachytherapy for endometrial cancer. She was unable to have intercourse despite attempted vaginal dilation. Her foreshortened vagina was successfully augmented with autologous buccal mucosa grafting at the apex, increasing her vaginal length to 8 cm and permitting pain-free intercourse. Even in the face of an altered surgical field after radical hysterectomy and radiation, autologous buccal mucosa is an option for vaginal reconstruction for vaginal foreshortening.

  11. Application of stem cells for cardiovascular grafts tissue engineering.

    PubMed

    Wu, Kaihong; Liu, Ying Long; Cui, Bin; Han, Zhongchao

    2006-06-01

    Congenital and acquired heart diseases are leading causes of morbidity and mortality world-wide. Currently, the synthetic materials or bioprosthetic replacement devices for cardiovascular surgery are imperfect and subject patients to one or more ongoing risks including thrombosis, limited durability and need for reoperations due to lack of growth in children and young adults. Suitable replacement grafts should have appropriate characteristics, including resistance to infection, low immunogenicity, good biocompatability and thromboresistance, with appropriate mechanical and physiological properties. Tissue engineering is a new scientific field aiming at fabrication of living, autologous grafts having structure or function properties that can be used to restore, maintain or improve tissue function. The use of autologous stem cells in cardiovascular tissue engineering is quite promising due to their capacity of self-renewal, high proliferation, and differentiation into specialized progeny. Progress has been made in engineering the various components of the cardiovascular system, including myocardial constructs, heart valves, and vascular patches or conduits with autologous stem cells. This paper will review the current achievements in stem cell-based cardiovascular grafts tissue engineering, with an emphasis on its clinical or possible clinical use in cardiovascular surgery.

  12. Tracheal reconstruction with a composite graft: fascial flap-wrapped allogenic aorta with external cartilage-ring support

    PubMed Central

    Wurtz, Alain; Hysi, Ilir; Kipnis, Eric; Zawadzki, Christophe; Hubert, Thomas; Jashari, Ramadan; Copin, Marie-Christine; Jude, Brigitte

    2013-01-01

    OBJECTIVES Animal and clinical studies have demonstrated the feasibility of tracheal replacement by silicone-stented allogenic aortas. In clinical trials, however, this graft did not show mature cartilage regeneration into the grafts as was observed in animal models. To solve this issue, we investigated tracheal replacement with a composite graft based on a fascial flap-wrapped allogenic aorta with external cartilage-ring support in a rabbit model. METHODS Seven male 'Géant des Flandres' and 'New Zealand' rabbits served as donors of aortas and cartilage rings, respectively. Nineteen female 'New Zealand' rabbits were used as recipients. First, in nine animals, neoangiogenesis of the composite graft following a wrap using a pedicled lateral thoracic fascial flap and implantation under the skin of the chest wall was investigated. Animal sacrifice was scheduled at regular intervals up to 38 days. Second, 10 animals underwent tracheal replacement with the composite graft after a 7-to-9 day revascularization period, and were followed-up to death. Macroscopic and microscopic examinations were used to study the morphology, stiffness and viability of the construct. RESULTS There was one operative death after tracheal replacement. The first group of animals was found to have a satisfactory tubular morphology and stiffness of their construct associated with preserved histological structure of cartilages and moderate to severe aortic ischaemic lesions. In the group of rabbits having undergone tracheal replacement, the anatomical results were characterized by a discrepancy between the severity of ischaemic lesions involving both allogenic aorta and cartilage rings and the satisfactory biomechanical characteristics of the graft in 7 of 10 animals, probably due to cartilage calcification deposits associated with inflammatory scar tissue ensuring the stiffness of the construct. CONCLUSIONS Our investigations demonstrate the feasibility of the replacement of circumferential

  13. Mechanical and biocompatible characterizations of a readily available multilayer vascular graft

    PubMed Central

    Madhavan, Krishna; Elliott, Winston H; Bonani, Walter; Monnet, Eric; Tan, Wei

    2013-01-01

    There is always a considerable clinical need for vascular grafts. Considering the availability, physical and mechanical properties, and regenerative potential, we have developed and characterized readily available, strong, and compliant multilayer grafts that support cell culture and ingrowth. The grafts were made from heterogeneous materials and structures, including a thin, dense, nanofibrous core composed of poly-ε-caprolactone (PCL), and a thick, porous, hydrogel sleeve composed of genipin-crosslinked collagen–chitosan (GCC). Because the difference in physicochemical properties between PCL and GCC caused layer separation, the layer adhesion was identified as a determinant to graft property and integrity under physiological conditions. Thus, strategies to modify the layer interface, including increasing porosity of the PCL surface, decreasing hydrophobicity, and increasing interlayer crosslinking, were developed. Results from microscopic images showed that increasing PCL porosity was characterized by improved layer adhesion. The resultant graft was characterized by high compliance (4.5%), and desired permeability (528 mL/cm2/min), burst strength (695 mmHg), and suture strength (2.38 N) for readily grafting. Results also showed that PCL mainly contributed to the graft mechanical properties, whereas GCC reduced the water permeability. In addition to their complementary contributions to physical and mechanical properties, the distinct graft layers also provided layer-specific structures for seeding and culture of vascular endothelial and smooth muscle cells in vitro. Acellular graft constructs were readily used to replace abdominal aorta of rabbits, resulting in rapid cell ingrowth and flow reperfusion. The multilayer constructs capable of sustaining physiological conditions and promoting cellular activities could serve as a platform for future development of regenerative vascular grafts. PMID:23165922

  14. Nonlinear and anisotropic tensile properties of graft materials used in soft tissue applications.

    PubMed

    Yoder, Jonathon H; Elliott, Dawn M

    2010-05-01

    The mechanical properties of extracellular matrix grafts that are intended to augment or replace soft tissues should be comparable to the native tissue. Such grafts are often used in fiber-reinforced tissue applications that undergo multi-axial loading and therefore knowledge of the anisotropic and nonlinear properties are needed, including the moduli and Poisson's ratio in two orthogonal directions within the plane of the graft. The objective of this study was to measure the tensile mechanical properties of several marketed grafts: Alloderm, Restore, CuffPatch, and OrthADAPT. The degree of anisotropy and non-linearity within each graft was evaluated from uniaxial tensile tests and compared to their native tissue. The Alloderm graft was anisotropic in both the toe- and linear-region of the stress-strain response, was highly nonlinear, and generally had low properties. The Restore and CuffPatch grafts had similar stress-strain responses, were largely isotropic, had a linear-region modulus of 18MPa, and were nonlinear. OrthADAPT was anisotropic in the linear-region (131 MPA vs 47MPa in the toe-region) and was highly nonlinear. The Poisson ratio for all grafts was between 0.4 and 0.7, except for the parallel orientation of Restore which was greater than 1.0. Having an informed understanding of how the available grafts perform mechanically will allow for better assessment by the physician for which graft to apply depending upon its application. Copyright 2010 Elsevier Ltd. All rights reserved.

  15. Automatic segmentation of the wire frame of stent grafts from CT data.

    PubMed

    Klein, Almar; van der Vliet, J Adam; Oostveen, Luuk J; Hoogeveen, Yvonne; Kool, Leo J Schultze; Renema, W Klaas Jan; Slump, Cornelis H

    2012-01-01

    Endovascular aortic replacement (EVAR) is an established technique, which uses stent grafts to treat aortic aneurysms in patients at risk of aneurysm rupture. Late stent graft failure is a serious complication in endovascular repair of aortic aneurysms. Better understanding of the motion characteristics of stent grafts will be beneficial for designing future devices. In addition, analysis of stent graft movement in individual patients in vivo can be valuable for predicting stent graft failure in these patients. To be able to gather information on stent graft motion in a quick and robust fashion, we propose an automatic method to segment stent grafts from CT data, consisting of three steps: the detection of seed points, finding the connections between these points to produce a graph, and graph processing to obtain the final geometric model in the form of an undirected graph. Using annotated reference data, the method was optimized and its accuracy was evaluated. The experiments were performed using data containing the AneuRx and Zenith stent grafts. The algorithm is robust for noise and small variations in the used parameter values, does not require much memory according to modern standards, and is fast enough to be used in a clinical setting (65 and 30s for the two stent types, respectively). Further, it is shown that the resulting graphs have a 95% (AneuRx) and 92% (Zenith) correspondence with the annotated data. The geometric model produced by the algorithm allows incorporation of high level information and material properties. This enables us to study the in vivo motions and forces that act on the frame of the stent. We believe that such studies will provide new insights into the behavior of the stent graft in vivo, enables the detection and prediction of stent failure in individual patients, and can help in designing better stent grafts in the future. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Clinical implications in the use of the PBC algorithm versus the AAA by comparison of different NTCP models/parameters

    PubMed Central

    2013-01-01

    Purpose Retrospective analysis of 3D clinical treatment plans to investigate qualitative, possible, clinical consequences of the use of PBC versus AAA. Methods The 3D dose distributions of 80 treatment plans at four different tumour sites, produced using PBC algorithm, were recalculated using AAA and the same number of monitor units provided by PBC and clinically delivered to each patient; the consequences of the difference on the dose-effect relations for normal tissue injury were studied by comparing different NTCP model/parameters extracted from a review of published studies. In this study the AAA dose calculation is considered as benchmark data. The paired Student t-test was used for statistical comparison of all results obtained from the use of the two algorithms. Results In the prostate plans, the AAA predicted lower NTCP value (NTCPAAA) for the risk of late rectal bleeding for each of the seven combinations of NTCP parameters, the maximum mean decrease was 2.2%. In the head-and-neck treatments, each combination of parameters used for the risk of xerostemia from irradiation of the parotid glands involved lower NTCPAAA, that varied from 12.8% (sd=3.0%) to 57.5% (sd=4.0%), while when the PBC algorithm was used the NTCPPBC’s ranging was from 15.2% (sd=2.7%) to 63.8% (sd=3.8%), according the combination of parameters used; the differences were statistically significant. Also NTCPAAA regarding the risk of radiation pneumonitis in the lung treatments was found to be lower than NTCPPBC for each of the eight sets of NTCP parameters; the maximum mean decrease was 4.5%. A mean increase of 4.3% was found when the NTCPAAA was calculated by the parameters evaluated from dose distribution calculated by a convolution-superposition (CS) algorithm. A markedly different pattern was observed for the risk relating to the development of pneumonitis following breast treatments: the AAA predicted higher NTCP value. The mean NTCPAAA varied from 0.2% (sd = 0.1%) to 2.1% (sd = 0

  17. Clinical implications in the use of the PBC algorithm versus the AAA by comparison of different NTCP models/parameters.

    PubMed

    Bufacchi, Antonella; Nardiello, Barbara; Capparella, Roberto; Begnozzi, Luisa

    2013-07-04

    Retrospective analysis of 3D clinical treatment plans to investigate qualitative, possible, clinical consequences of the use of PBC versus AAA. The 3D dose distributions of 80 treatment plans at four different tumour sites, produced using PBC algorithm, were recalculated using AAA and the same number of monitor units provided by PBC and clinically delivered to each patient; the consequences of the difference on the dose-effect relations for normal tissue injury were studied by comparing different NTCP model/parameters extracted from a review of published studies. In this study the AAA dose calculation is considered as benchmark data. The paired Student t-test was used for statistical comparison of all results obtained from the use of the two algorithms. In the prostate plans, the AAA predicted lower NTCP value (NTCPAAA) for the risk of late rectal bleeding for each of the seven combinations of NTCP parameters, the maximum mean decrease was 2.2%. In the head-and-neck treatments, each combination of parameters used for the risk of xerostemia from irradiation of the parotid glands involved lower NTCPAAA, that varied from 12.8% (sd=3.0%) to 57.5% (sd=4.0%), while when the PBC algorithm was used the NTCPPBC's ranging was from 15.2% (sd=2.7%) to 63.8% (sd=3.8%), according the combination of parameters used; the differences were statistically significant. Also NTCPAAA regarding the risk of radiation pneumonitis in the lung treatments was found to be lower than NTCPPBC for each of the eight sets of NTCP parameters; the maximum mean decrease was 4.5%. A mean increase of 4.3% was found when the NTCPAAA was calculated by the parameters evaluated from dose distribution calculated by a convolution-superposition (CS) algorithm. A markedly different pattern was observed for the risk relating to the development of pneumonitis following breast treatments: the AAA predicted higher NTCP value. The mean NTCPAAA varied from 0.2% (sd = 0.1%) to 2.1% (sd = 0.3%), while the mean NTCPPBC

  18. Editor's Choice - Prolonged ICU Length of Stay after AAA Repair: Analysis of Time Trends and Long-term Outcome.

    PubMed

    Gavali, H; Mani, K; Tegler, G; Kawati, R; Covaciu, L; Wanhainen, A

    2017-08-01

    The aim of the study was to investigate the frequency and outcome of prolonged intensive care unit (ICU) length of stay (LOS) after abdominal aortic aneurysm (AAA) repair in the endovascular era. All patients operated on for AAA between 1999 and 2013 at Uppsala University hospital were identified. Data were retrieved from the Swedish Vascular registry, the Swedish Intensive Care registry, the National Population registry, and case records. Prolonged ICU LOS was defined as ≥ 48 h during the primary hospital stay. Patients surviving ≥ 48 h after AAA surgery were included in the analysis. A total of 725 patients were identified, of whom 707 (97.5%) survived ≥ 48 h; 563 (79.6%) underwent intact AAA repair and 144 (20.4%) ruptured AAA repair. A total of 548 patients (77.5%) required < 48 h of intensive care, 115 (16.3%) 2-6 days and 44 (6.2%) ≥ 7 days. The rate of prolonged ICU LOS declined considerably over time, from 41.4% of all AAA repairs in 1999 to 7.3% in 2013 (p < .001) whereas the use of endovascular aortic repair (EVAR) increased from 6.9% in 1999 to 78.0% in 2013 (p < .001). The 30 day survival rate was 98.2% for those with < 48 h ICU stay versus 93.0% for 2-6 days versus 81.8% for ≥ 7 days (p < .001); the corresponding 90 day survival was 97.1% versus 86.1% versus 63.6% (p < .001) respectively. For patients surviving 90 days after repair, there was no difference in long-term survival between the groups. During the period of progressively increasing use of EVAR, a simultaneous significant reduction in frequency of prolonged ICU LOS occurred. Although prolonged ICU LOS was associated with a high short-term mortality, long-term outcome among those surviving the initial 90 days was less affected. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  19. SU-E-T-122: Anisotropic Analytical Algorithm (AAA) Vs. Acuros XB (AXB) in Stereotactic Treatment Planning

    SciTech Connect

    Mynampati, D; Scripes, P Godoy; Kuo, H

    2015-06-15

    Purpose: To evaluate dosimetric differences between superposition beam model (AAA) and determinant photon transport solver (AXB) in lung SBRT and Cranial SRS dose computations. Methods: Ten Cranial SRS and ten Lung SBRT plans using Varian, AAA -11.0 were re-planned using Acuros -XB-11.0 with fixed MU. 6MV photon Beam model with HD120-MLC used for dose calculations. Four non-coplanar conformal arcs used to deliver 21Gy or 18Gy to SRS targets (0.4 to 6.2cc). 54Gy (3Fractions) or 50Gy (5Fractions) was planned for SBRT targets (7.3 to 13.9cc) using two VAMT non-coplanar arcs. Plan comparison parameters were dose to 1% PTV volume (D1), dosemore » to 99% PTV volume( D99), Target mean (Dmean), Conformity index (ratio of prescription isodose volume to PTV), Homogeneity Index [ (D2%-D98%)/Dmean] and R50 (ratio of 50% of prescription isodose volume to PTV). OAR parameters were Brain volume receiving 12Gy dose (V12Gy) and maximum dose (D0.03) to Brainstem for SRS. For lung SBRT, maximum dose to Heart and Cord, Mean lung dose (MLD) and volume of lung receiving 20Gy (V20Gy) were computed. PTV parameters compared by percentage difference between AXB and AAA parameters. OAR parameters and HI compared by absolute difference between two calculations. For analysis, paired t-test performed over the parameters. Results: Compared to AAA, AXB SRS plans have on average 3.2% lower D99, 6.5% lower CI and 3cc less Brain-V12. However, AXB SBRT plans have higher D1, R50 and Dmean by 3.15%, 1.63% and 2.5%. For SRS and SBRT, AXB plans have average HI 2 % and 4.4% higher than AAA plans. In both techniques, all other parameters vary within 1% or 1Gy. In both sets only two parameters have P>0.05. Conclusion: Even though t-test results signify difference between AXB and AAA plans, dose differences in dose estimations by both algorithms are clinically insignificant.« less

  20. Toward beta cell replacement for diabetes

    PubMed Central

    Johannesson, Bjarki; Sui, Lina; Freytes, Donald O; Creusot, Remi J; Egli, Dieter

    2015-01-01

    The discovery of insulin more than 90 years ago introduced a life-saving treatment for patients with type 1 diabetes, and since then, significant progress has been made in clinical care for all forms of diabetes. However, no method of insulin delivery matches the ability of the human pancreas to reliably and automatically maintain glucose levels within a tight range. Transplantation of human islets or of an intact pancreas can in principle cure diabetes, but this approach is generally reserved for cases with simultaneous transplantation of a kidney, where immunosuppression is already a requirement. Recent advances in cell reprogramming and beta cell differentiation now allow the generation of personalized stem cells, providing an unlimited source of beta cells for research and for developing autologous cell therapies. In this review, we will discuss the utility of stem cell-derived beta cells to investigate the mechanisms of beta cell failure in diabetes, and the challenges to develop beta cell replacement therapies. These challenges include appropriate quality controls of the cells being used, the ability to generate beta cell grafts of stable cellular composition, and in the case of type 1 diabetes, protecting implanted cells from autoimmune destruction without compromising other aspects of the immune system or the functionality of the graft. Such novel treatments will need to match or exceed the relative safety and efficacy of available care for diabetes. PMID:25733347

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

    PubMed Central

    Boronat-García, Alejandra; Palomero-Rivero, Marcela; Guerra-Crespo, Magdalena; Millán-Aldaco, Diana; Drucker-Colín, René

    2016-01-01

    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. PMID:27525967

  2. Biological tooth replacement

    PubMed Central

    Sartaj, Rachel; Sharpe, Paul

    2006-01-01

    Teeth develop from a series of reciprocal interactions that take place between epithelium and mesenchyme during development of the mouth that begin early in mammalian embryogenesis. The molecular control of key processes in tooth development such as initiation, morphogenesis and cytodifferentiation are being increasingly better understood, to the point where this information can be used as the basis for approaches to produce biological replacement teeth (BioTeeth). This review outlines the current approaches, ideas and progress towards the production of BioTeeth that could form an alternative method for replacing lost or damaged teeth. PMID:17005022

  3. Materials Related Forensic Analysis and Special Testing : Drying Shrinkage Evaluation of Bridge Decks with Class AAA and Class W/WD Type K Cement

    DOT National Transportation Integrated Search

    2001-07-01

    This work pertains to preparation of concrete drying shrinkage data for proposed concrete mixtures during normal concrete : trial batch verification. Selected concrete mixtures will include PennDOT Classes AAA and AA and will also include the use of ...

  4. Dermis-Fat Graft in Children as Primary and Secondary Orbital Implant.

    PubMed

    Quaranta-Leoni, Francesco M; Sposato, Sabrina; Raglione, Pietro; Mastromarino, Angelo

    2016-01-01

    To report the experience with the use of dermis-fat graft in the pediatric population and to evaluate the outcome of this procedure as a primary or secondary orbital implant. Case series. Analysis of the clinical charts of 22 patients. Age at the time of surgery ranged from 2.1 to 13 years. Three patients affected were submitted to evisceration with primary dermis-fat graft. Six patients had explantation of exposed implants and a replacement with a dermis-fat graft. Three patients had a dermis-fat graft to repair contracted sockets. Ten patients were affected by congenital anophthalmia: 4 patients had a primary dermis-fat graft, 6 patients had a removal of a socket expander, or an orbital spherical expander, or pellet expanders and a replacement with a dermis-fat graft. This study adheres to the principles outlined in the Declaration of Helsinki. The patients' follow up ranged between 2.5 and 8 years. Only 1 child who had a primary dermis-fat graft experienced excessive growth of the implant, managed by surgical debulking. In the end, all the patients showed satisfactory orbital volume along with adequate fornices. The dermis-fat graft as a primary implant may be useful in children with severe scleromalacia or following ocular trauma. It is a suitable option in children affected by congenital anophthalmia as it helps continued socket expansion. It can also be considered in the pediatric population to address the volume deficit following explantation of exposed implants and in contracted sockets.

  5. AAAS Mass Media Science and Engineering Fellowship Program: Building Communication Skills in Young Scientists

    NASA Astrophysics Data System (ADS)

    Pasco, S.

    2006-12-01

    The AAAS Mass Media Science &Engineering Fellowship program has succeeded in training scientists to become more effective communicators for more than 30 years. The program places advanced science, engineering and mathematics students at media sites to work as science reporters for ten weeks each summer. AAAS places between 15 to 20 students a year at newspapers, magazines and radio stations. Our goal is to create better science communicators who understand their role in fostering the public's understanding of science. Fellows leave the program with a greater awareness of how to communicate complex issues by making the connection as to why people should be interested in certain developments, and more specifically, how they will impact their communities. 2004 AGU Fellow Rei Ueyama put her lessons learned to good use during her Fellowship at the Sacramento Bee. "In a regional paper like The Bee, a (story) also had to have a local touch. I needed to show why people in Sacramento (or California) should bother to read the story. One example is the story I wrote about seeding the ocean with iron particles to fight global warming. Since ocean fertilization is a global issue, I had to clearly specify the reason why The Bee and not The New York Times was running the story. The local angle I chose was to point out that the core group of scientists involved in this study was from Monterey Bay, Calif." Many alumni tell us the program has been an integral force in shaping the course of their career. Similarly, sites often report that having a scientist on staff is an invaluable resource that allows them to cover additional science stories as well as report some technical stories in more depth. The American Geophysical Union has sponsored a Mass Media Fellow since 1997. Sponsorship allows affiliate program partners to establish connections with young professionals in their field. They are then also able to take advantage of the communication skills resident in their alumni base

  6. Reoperation for composite valve graft failure: Operative results and midterm survival.

    PubMed

    Maroto, Luis C; Carnero, Manuel; Cobiella, Javier; García, Mónica; Vilacosta, Isidre; Reguillo, Fernando; Villagrán, Enrique; Olmos, Carmen

    2018-06-01

    The replacement of a failed composite valve graft is technically more demanding and is associated with increased morbidity and mortality. We present our technique and outcomes for reoperations for composite graft failures. Between September 2011 and June 2017, 14 patients underwent a redo composite graft replacement. Twelve patients (85.7%) were male, and mean age was 58.4 years ± 12 standard deviation (SD). One patient had two previous root replacements. Indications for reoperation were endocarditis (8), aortic pseudoaneurysm (3), and aortic prosthesis thrombosis (3). Mean logistic EuroSCORE and EuroSCORE II were 30.8% and 14.7%, respectively. A mechanical composite graft was used in 12 patients and biological composite grafts were used in two patients. Hospital mortality was 14.3% (n = 2). One patient (7.1%) required reoperation for bleeding, One patient (7.1%) had mechanical ventilation >24 h, and four patients (28.6%) required implantation of a permanent pacemaker. Median intensive care unit and hospital stays were 3 days (interquartile range [IQR] 1-5) and 10 days (IQR 6.5-38.5). One patient experienced recurrent prosthetic valve endocarditis 14 months after operation. On follow-up, 11 of 12 survivors were in New York Heart Association class I or II. Survival at 3 years was 85.7% ± 9.4% SD. Composite valve graft replacement can be performed with acceptable morbidity and mortality with good mid-term survival. © 2018 Wiley Periodicals, Inc.

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

    PubMed

    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.

  8. Studies in fat grafting: Part III. Fat grafting irradiated tissue--improved skin quality and decreased fat graft retention.

    PubMed

    Garza, Rebecca M; Paik, Kevin J; Chung, Michael T; Duscher, Dominik; Gurtner, Geoffrey C; Longaker, Michael T; Wan, Derrick C

    2014-08-01

    Following radiation therapy, skin becomes fibrotic and can present a difficult problem for reconstructive surgeons. There is an increasing belief that fat grafting under irradiated skin can reverse the damage caused by radiation. The present study evaluated the effect of fat grafting on irradiated skin, along with fat graft quality and retention rates in irradiated tissue. Nine adult Crl:NU-Foxn1 CD-1 mice underwent 30-Gy external beam irradiation of the scalp. Four weeks after irradiation, scalp skin from irradiated and nonirradiated mice was harvested and compared histologically for dermal thickness, collagen content, and vascular density. Human fat grafts were then injected in the subcutaneous plane of the scalp. Skin assessment was performed in the irradiated group at 2 and 8 weeks after grafting, and fat graft retention was measured at baseline and every 2 weeks up to 8 weeks after grafting using micro-computed tomography. Finally, fat graft samples were explanted at 8 weeks, and quality scoring was performed. Fat grafting resulted in decreased dermal thickness, decreased collagen content, and increased vascular density in irradiated skin. Computed tomographic analysis revealed significantly decreased fat graft survival in the irradiated group compared with the nonirradiated group. Histologic scoring of explanted fat grafts demonstrated no difference in quality between the irradiated and nonirradiated groups. Fat grafting attenuates dermal collagen deposition and vessel depletion characteristic of radiation fibrosis. Although fat graft retention rates are significantly lower in irradiated than in nonirradiated tissue, the quality of retained fat between the groups is similar.

  9. Obesity is not an independent risk factor for adverse perioperative and long-term clinical outcomes following open AAA repair or EVAR.

    PubMed

    Park, Brian; Dargon, Phong; Binette, Christopher; Babic, Bruna; Thomas, Tina; Divinagracia, Thomas; Dahn, Michael S; Menzoian, James O

    2011-10-01

    Moderate (body mass index [BMI] ≥30) and morbid obesity (BMI ≥35) is increasing at an alarming rate in vascular surgery patients. The objective of this study was to determine the impact of obesity on perioperative and long-term clinical outcomes following open abdominal aortic aneurysm (AAA) repair or endovascular aneurysm repair (EVAR). This review includes patients that underwent open AAA repair (n = 403) or EVAR (n = 223) from 1999 to 2009. Specific patient characteristics such as comorbid diseases, medications, and body mass index (BMI) were assessed. Specific perioperative outcomes such as length of stay, myocardial infarctions, and mortality were reviewed. In addition, long-term outcomes such as rates of reintervention, permanent renal dysfunction, and mortality beyond 30 days were also assessed. The incidence of obesity in open AAA patients was 25.3% (documented incidence 1.5%) and for EVAR was 24.6% (documented incidence 4%). Moderate and morbid obesity was associated with longer intensive care unit (ICU) admissions for both open AAA or EVAR patients (P < .05). However, no significant differences in perioperative outcomes in terms of overall length of stay, myocardial infarction, acute renal failure, wound infections, or mortality were noted between obese and nonobese patients underoing open AAA repair or EVAR (P > .05). Similarly, moderate and morbid obesity was not associated with significant differences in rates of reintervention, permanent renal dysfunction, and mortality beyond 30 days for patients undergoing open AAA repair or EVAR (P > .05). The results of this study indicate that moderate and morbid obesity are not independently associated with adverse perioperative and long-term clinical outcomes for patients undergoing open AAA repair or EVAR. Therefore, either open AAA repair or EVAR can be accomplished safely in moderately obese and morbidly obese patients.

  10. Analysis of the cooperative ATPase cycle of the AAA+ chaperone ClpB from Thermus thermophilus by using ordered heterohexamers with an alternating subunit arrangement.

    PubMed

    Yamasaki, Takashi; Oohata, Yukiko; Nakamura, Toshiki; Watanabe, Yo-hei

    2015-04-10

    The ClpB/Hsp104 chaperone solubilizes and reactivates protein aggregates in cooperation with DnaK/Hsp70 and its cofactors. The ClpB/Hsp104 protomer has two AAA+ modules, AAA-1 and AAA-2, and forms a homohexamer. In the hexamer, these modules form a two-tiered ring in which each tier consists of homotypic AAA+ modules. By ATP binding and its hydrolysis at these AAA+ modules, ClpB/Hsp104 exerts the mechanical power required for protein disaggregation. Although ATPase cycle of this chaperone has been studied by several groups, an integrated understanding of this cycle has not been obtained because of the complexity of the mechanism and differences between species. To improve our understanding of the ATPase cycle, we prepared many ordered heterohexamers of ClpB from Thermus thermophilus, in which two subunits having different mutations were cross-linked to each other and arranged alternately and measured their nucleotide binding, ATP hydrolysis, and disaggregation abilities. The results indicated that the ATPase cycle of ClpB proceeded as follows: (i) the 12 AAA+ modules randomly bound ATP, (ii) the binding of four or more ATP to one AAA+ ring was sensed by a conserved Arg residue and converted another AAA+ ring into the ATPase-active form, and (iii) ATP hydrolysis occurred cooperatively in each ring. We also found that cooperative ATP hydrolysis in at least one ring was needed for the disaggregation activity of ClpB. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Effect of microgravity simulation using 3D clinostat on cavendish banana (Musa acuminata AAA Group) ripening process

    NASA Astrophysics Data System (ADS)

    Dwivany, Fenny Martha; Esyanti, Rizkita R.; Prapaisie, Adeline; Puspa Kirana, Listya; Latief, Chunaeni; Ginaldi, Ari

    2016-11-01

    The objective of the research was to determine the effect of microgravity simulation by 3D clinostat on Cavendish banana (Musa acuminata AAA group) ripening process. In this study, physical, physiological changes as well as genes expression were analysed. The result showed that in microgravity simulation condition ripening process in banana was delayed and the MaACOl, MaACSl and MaACS5 gene expression were affected.

  12. Knee joint replacement

    MedlinePlus

    ... Knee joint replacement - series References American Academy of Orthopedic Surgeons (AAOS) website. Treatment of osteoarthritis of the knee: evidence-based guideline 2nd edition (summary) . www.aaos.org/research/guidelines/TreatmentofOsteoarthritisoftheKneeGuideline.pdf . Updated May 18, 2013. Accessed ...

  13. Replacing America's Job Bank

    ERIC Educational Resources Information Center

    Vollman, Jim

    2009-01-01

    The Job Central National Labor Exchange (www.jobcentral.com) has become the effective replacement for America's Job Bank with state workforce agencies and, increasingly, with community colleges throughout the country. The American Association of Community Colleges (AACC) has formed a partnership with Job Central to promote its use throughout the…

  14. Hip Replacement - Multiple Languages

    MedlinePlus

    ... Hip Replacement - العربية (Arabic) Bilingual PDF Health Information Translations Chinese, Simplified (Mandarin dialect) (简体中文) Expand Section Total ... Chinese, Simplified (Mandarin dialect)) Bilingual PDF Health Information Translations Chinese, Traditional (Cantonese dialect) (繁體中文) Expand Section Total ...

  15. Prioritizing equipment for replacement.

    PubMed

    Capuano, Mike

    2010-01-01

    It is suggested that clinical engineers take the lead in formulating evaluation processes to recommend equipment replacement. Their skill, knowledge, and experience, combined with access to equipment databases, make them a logical choice. Based on ideas from Fennigkoh's scheme, elements such as age, vendor support, accumulated maintenance cost, and function/risk were used.6 Other more subjective criteria such as cost benefits and efficacy of newer technology were not used. The element of downtime was also omitted due to the data element not being available. The resulting Periop Master Equipment List and its rationale was presented to the Perioperative Services Program Council. They deemed the criteria to be robust and provided overwhelming acceptance of the list. It was quickly put to use to estimate required capital funding, justify items already thought to need replacement, and identify high-priority ranked items for replacement. Incorporating prioritization criteria into an existing equipment database would be ideal. Some commercially available systems do have the basic elements of this. Maintaining replacement data can be labor-intensive regardless of the method used. There is usually little time to perform the tasks necessary for prioritizing equipment. However, where appropriate, a clinical engineering department might be able to conduct such an exercise as shown in the following case study.

  16. AAA and AXB algorithms for the treatment of nasopharyngeal carcinoma using IMRT and RapidArc techniques.

    PubMed

    Kamaleldin, Maha; Elsherbini, Nader A; Elshemey, Wael M

    2017-09-27

    The aim of this study is to evaluate the impact of anisotropic analytical algorithm (AAA) and 2 reporting systems (AXB-D m and AXB-D w ) of Acuros XB algorithm (AXB) on clinical plans of nasopharyngeal patients using intensity-modulated radiotherapy (IMRT) and RapidArc (RA) techniques. Six plans of different algorithm-technique combinations are performed for 10 patients to calculate dose-volume histogram (DVH) physical parameters for planning target volumes (PTVs) and organs at risk (OARs). The number of monitor units (MUs) and calculation time are also determined. Good coverage is reported for all algorithm-technique combination plans without exceeding the tolerance for OARs. Regardless of the algorithm, RA plans persistently reported higher D 2% values for PTV-70. All IMRT plans reported higher number of MUs (especially with AXB) than did RA plans. AAA-IMRT produced the minimum calculation time of all plans. Major differences between the investigated algorithm-technique combinations are reported only for the number of MUs and calculation time parameters. In terms of these 2 parameters, it is recommended to employ AXB in calculating RA plans and AAA in calculating IMRT plans to achieve minimum calculation times at reduced number of MUs. Copyright © 2017 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  17. Regulatory coiled-coil domains promote head-to-head assemblies of AAA+ chaperones essential for tunable activity control.

    PubMed

    Carroni, Marta; Franke, Kamila B; Maurer, Michael; Jäger, Jasmin; Hantke, Ingo; Gloge, Felix; Linder, Daniela; Gremer, Sebastian; Turgay, Kürşad; Bukau, Bernd; Mogk, Axel

    2017-11-22

    Ring-forming AAA+ chaperones exert ATP-fueled substrate unfolding by threading through a central pore. This activity is potentially harmful requiring mechanisms for tight repression and substrate-specific activation. The AAA+ chaperone ClpC with the peptidase ClpP forms a bacterial protease essential to virulence and stress resistance. The adaptor MecA activates ClpC by targeting substrates and stimulating ClpC ATPase activity. We show how ClpC is repressed in its ground state by determining ClpC cryo-EM structures with and without MecA. ClpC forms large two-helical assemblies that associate via head-to-head contacts between coiled-coil middle domains (MDs). MecA converts this resting state to an active planar ring structure by binding to MD interaction sites. Loss of ClpC repression in MD mutants causes constitutive activation and severe cellular toxicity. These findings unravel an unexpected regulatory concept executed by coiled-coil MDs to tightly control AAA+ chaperone activity.

  18. Plant grafting: new mechanisms, evolutionary implications.

    PubMed

    Goldschmidt, Eliezer E

    2014-01-01

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

  19. Plant grafting: new mechanisms, evolutionary implications

    PubMed Central

    Goldschmidt, Eliezer E.

    2014-01-01

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

  20. Causes of corneal graft failure in India.

    PubMed

    Dandona, L; Naduvilath, T J; Janarthanan, M; Rao, G N

    1998-09-01

    The success of corneal grafting in visual rehabilitation of the corneal blind in India depends on survival of the grafts. Understanding the causes of graft failure may help reduce the risk of failure. We studied these causes in a series of 638 graft failures at our institution. Multivariate logistic regression analysis was used to evaluate the association of particular causes of graft failure with indications for grafting, socioeconomic status, age, sex, host corneal vascularization, donor corneal quality, and experience of surgeon. The major causes of graft failure were allograft rejection (29.2%), increased intraocular pressure (16.9%), infection excluding endophthalmitis (15.4%), and surface problems (12.7%). The odds of infection causing graft failure were significantly higher in patients of lower socioeconomic status (odds ratio 2.45, 95% CI 1.45-4.15). Surface problems as a cause of graft failure was significantly associated with grafts done for corneal scarring or for regrafts (odds ratio 3.36, 95% CI 1.80-6.30). Increased intraocular pressure as a cause of graft failure had significant association with grafts done for aphakic or pseudophakic bullous keratopathy, congenital conditions or glaucoma, or regrafts (odds ratio 2.19, 95% CI 1.25-3.84). Corneal dystrophy was the indication for grafting in 12 of the 13 cases of graft failure due to recurrence of host disease. Surface problems, increased intraocular pressure, and infection are modifiable risk factors that are more likely to cause graft failure in certain categories of patients in India. Knowledge about these associations can be helpful in looking for and aggressively treating these modifiable risk factors in the at-risk categories of corneal graft patients. This can possibly reduce the chance of graft failure.

  1. Upper limb grafts for hemodialysis access.

    PubMed

    Shemesh, David; Goldin, Ilya; Verstandig, Anthony; Berelowitz, Daniel; Zaghal, Ibrahim; Olsha, Oded

    2015-01-01

    Arteriovenous (AV) grafts are required for hemodialysis access when options for native fistulas have been fully exhausted, where they continue to play an important role in hemodialysis patients, offering a better alternative to central vein catheters. When planning autogenous accesses using Doppler ultrasound, adequate arterial inflow and venous outflow must be consciously preserved for future access creation with grafts. Efforts to improve graft patency include changing graft configuration, graft biology and hemodynamics. Industry offers early cannulation grafts to reduce central catheter use and a bioengineered graft is undergoing clinical studies. Although the outcome of AV grafts is inferior to fistulas, grafts can provide long-term hemodialysis access that is a better alternative to central venous catheters. AV grafts have significant drawbacks, mainly poor patency, infection and cost but also have some advantages: early maturation, ease of creation and needling and widespread availability. The outcome of AV graft surgery is variable from center to center. The primary patency rate for AV grafts is 58% at 6 months and the secondary patency rate is 76% at 6 months and 55% at 18 months. There are centers of excellence that report a 1 year secondary patency rate of up to 91%. In this review of the use of AV grafts for hemodialysis access in the upper extremities, technical issues involved in planning the access and performing the surgery in its different configurations are discussed and the role of surveillance and maintenance with their attendant surgical and radiological interventions is described.

  2. Agreement between activity-monitoring devices during home rehabilitation: a substudy of the AAA STOP trial.

    PubMed

    Myers, Jonathan; Dupain, Mandi; Vu, Andrew; Jaffe, Alyssa; Smith, Kimberly; Fonda, Holly; Dalman, Ronald

    2014-01-01

    As part of a home-based rehabilitation program, 24 older adult patients (71 ± 3 years) with abdominal aortic aneurysm (AAA) disease underwent 3 days (12 awake hr/day) of activity monitoring using an accelerometer (ACC), a pedometer, and a heart rate (HR) monitor, and recorded hourly activity logs. Subjects then underwent an interview to complete a 3-day activity recall questionnaire (3-DR). Mean energy expenditure (EE) in kcals/ day for HR, ACC, and 3-DR were 1,687 ± 458, 2,068 ± 529, and 1,974 ± 491, respectively. Differences in EE were not significant between 3-DR and ACC, but HR differed from both ACC (p < .001) and 3-DR (p < .01). ACC and 3-DR had the highest agreement, with a coefficient of variation of 7.9% and r = .86. Thus, ACC provided a reasonably accurate reflection of EE based the criterion measure, an activity recall questionnaire. ACC can be effectively used to monitor EE to achieve an appropriate training stimulus during home-based cardiac rehabilitation.

  3. Structure of a AAA+ unfoldase in the process of unfolding substrate

    PubMed Central

    Ripstein, Zev A; Huang, Rui; Augustyniak, Rafal; Kay, Lewis E; Rubinstein, John L

    2017-01-01

    AAA+ unfoldases are thought to unfold substrate through the central pore of their hexameric structures, but how this process occurs is not known. VAT, the Thermoplasma acidophilum homologue of eukaryotic CDC48/p97, works in conjunction with the proteasome to degrade misfolded or damaged proteins. We show that in the presence of ATP, VAT with its regulatory N-terminal domains removed unfolds other VAT complexes as substrate. We captured images of this transient process by electron cryomicroscopy (cryo-EM) to reveal the structure of the substrate-bound intermediate. Substrate binding breaks the six-fold symmetry of the complex, allowing five of the six VAT subunits to constrict into a tight helix that grips an ~80 Å stretch of unfolded protein. The structure suggests a processive hand-over-hand unfolding mechanism, where each VAT subunit releases the substrate in turn before re-engaging further along the target protein, thereby unfolding it. DOI: http://dx.doi.org/10.7554/eLife.25754.001 PMID:28390173

  4. The Rice AAA-ATPase OsFIGNL1 Is Essential for Male Meiosis

    PubMed Central

    Zhang, Peipei; Zhang, Yingxin; Sun, Lianping; Sinumporn, Sittipun; Yang, Zhengfu; Sun, Bin; Xuan, Dandan; Li, Zihe; Yu, Ping; Wu, Weixun; Wang, Kejian; Cao, Liyong; Cheng, Shihua

    2017-01-01

    Meiosis is crucial in reproduction of plants and ensuring genetic diversity. Although several genes involved in homologous recombination and DNA repair have been reported, their functions in rice (Oryza sativa) male meiosis remain poorly understood. Here, we isolated and characterized the rice OsFIGNL1 (OsFidgetin-like 1) gene, encoding a conserved AAA-ATPase, and explored its function and importance in male meiosis and pollen formation. The rice Osfignl1 mutant exhibited normal vegetative growth, but failed to produce seeds and displayed pollen abortion phenotype. Phenotypic comparisons between the wild-type and Osfignl1 mutant demonstrated that OsFIGNL1 is required for anther development, and that the recessive mutation of this gene causes male sterility in rice. Complementation and CRISPR/Cas9 experiments demonstrated that wild-type OsFIGNL1 is responsible for the male sterility phenotype. Subcellular localization showed that OsFIGNL1-green fluorescent protein was exclusively localized in the nucleus of rice protoplasts. Male meiosis in the Osfignl1 mutant exhibited abnormal chromosome behavior, including chromosome bridges and multivalent chromosomes at diakinesis, lagging chromosomes, and chromosome fragments during meiosis. Yeast two-hybrid assays demonstrated OsFIGNL1 could interact with RAD51A1, RAD51A2, DMC1A, DMC1B, and these physical interactions were further confirmed by BiFC assay. Taken together, our results suggest that OsFIGNL1 plays an important role in regulation of male meiosis and anther development. PMID:29021797

  5. The AAA+ ATPase TRIP13 remodels HORMA domains through N-terminal engagement and unfolding

    SciTech Connect

    Ye, Qiaozhen; Kim, Dong Hyun; Dereli, Ihsan

    Proteins of the conserved HORMA domain family, including the spindle assembly checkpoint protein MAD2 and the meiotic HORMADs, assemble into signaling complexes by binding short peptides termed “closure motifs”. The AAA+ ATPase TRIP13 regulates both MAD2 and meiotic HORMADs by disassembling these HORMA domain–closure motif complexes, but its mechanisms of substrate recognition and remodeling are unknown. Here, we combine X-ray crystallography and crosslinking mass spectrometry to outline how TRIP13 recognizes MAD2 with the help of the adapter protein p31comet. We show that p31comet binding to the TRIP13 N-terminal domain positions the disordered MAD2 N-terminus for engagement by the TRIP13 “poremore » loops”, which then unfold MAD2 in the presence of ATP. N-terminal truncation of MAD2 renders it refractory to TRIP13 action in vitro, and in cells causes spindle assembly checkpoint defects consistent with loss of TRIP13 function. Similar truncation of HORMAD1 in mouse spermatocytes compromises its TRIP13-mediated removal from meiotic chromosomes, highlighting a conserved mechanism for recognition and disassembly of HORMA domain–closure motif complexes by TRIP13.« less

  6. 3D Printed Abdominal Aortic Aneurysm Phantom for Image Guided Surgical Planning with a Patient Specific Fenestrated Endovascular Graft System.

    PubMed

    Meess, Karen M; Izzo, Richard L; Dryjski, Maciej L; Curl, Richard E; Harris, Linda M; Springer, Michael; Siddiqui, Adnan H; Rudin, Stephen; Ionita, Ciprian N

    2017-02-11

    Following new trends in precision medicine, Juxatarenal Abdominal Aortic Aneurysm (JAAA) treatment has been enabled by using patient-specific fenestrated endovascular grafts. The X-ray guided procedure requires precise orientation of multiple modular endografts within the arteries confirmed via radiopaque markers. Patient-specific 3D printed phantoms could familiarize physicians with complex procedures and new devices in a risk-free simulation environment to avoid periprocedural complications and improve training. Using the Vascular Modeling Toolkit (VMTK), 3D Data from a CTA imaging of a patient scheduled for Fenestrated EndoVascular Aortic Repair (FEVAR) was segmented to isolate the aortic lumen, thrombus, and calcifications. A stereolithographic mesh (STL) was generated and then modified in Autodesk MeshMixer for fabrication via a Stratasys Eden 260 printer in a flexible photopolymer to simulate arterial compliance. Fluoroscopic guided simulation of the patient-specific FEVAR procedure was performed by interventionists using all demonstration endografts and accessory devices. Analysis compared treatment strategy between the planned procedure, the simulation procedure, and the patient procedure using a derived scoring scheme. With training on the patient-specific 3D printed AAA phantom, the clinical team optimized their procedural strategy. Anatomical landmarks and all devices were visible under x-ray during the simulation mimicking the clinical environment. The actual patient procedure went without complications. With advances in 3D printing, fabrication of patient specific AAA phantoms is possible. Simulation with 3D printed phantoms shows potential to inform clinical interventional procedures in addition to CTA diagnostic imaging.

  7. Patient and Aneurysm Characteristics Predicting Prolonged Length of Stay After Elective Open AAA Repair in the Endovascular Era.

    PubMed

    Casillas-Berumen, Sergio; Rojas-Miguez, Florencia A; Farber, Alik; Komshian, Sevan; Kalish, Jeffrey A; Rybin, Denis; Doros, Gheorghe; Siracuse, Jeffrey J

    2018-01-01

    Open aortic aneurysm repair (AAA) repair can be resource intensive and associated with a prolonged length of stay (LOS). We sought to examine patient and aneurysm predictors of prolonged LOS to better identify those at risk in the preoperative setting. Patient data were obtained from the targeted AAA American College of Surgery National Surgical Quality Improvement Program database from 2012 to 2014 of patients undergoing open AAA repair. Multivariable logistic regression was used to determine predictors of prolonged postoperative LOS defined as greater than 10 days (75th percentile). There were 1172 open AAA repairs identified. The majority (54%) of patients were older than 70 years and male (74%). Surgical approach was transperitoneal (70.9%) and retroperitoneal (29.1%). Aneurysms were 51.4% infrarenal, 33% juxtarenal, 5.7% pararenal, 7.4% suprarenal, and 2.5% type IV thoracoabdominal. Mean and median LOS were 9.1 ± 7.4 and 7 (0-72) days, respectively. Independently associated with extended LOS factors were visceral revascularization (odds ratio [OR]: 5.32, 95% confidence interval [CI]: 2.77-10.22, P < .001), type IV thoracoabdominal extent (OR: 3.09, 95% CI: 1.01-9.46, P = .048), suprarenal extent (OR: 1.89, 95% CI: 1.07-3.34, P = .029) and juxtarenal (OR: 1.43, 95% CI: 1.01-2.02, P = .004), non-Caucasian race (OR: 2.80, 95% CI: 1.77-4.41, P < .001), chronic obstructive pulmonary disease (OR: 1.76, 95% CI: 1.20-2.59, P = .004), not-from-home admission (OR: 1.91, 95% CI: 1.13-3.24), and age greater than 70 (OR: 1.49, 95% CI: 1.08-2.05, P = .014). We identified patient and aneurysm characteristics independently associated with protracted LOS following open AAA repair. Prospective identification of high-risk patients may allow physicians and hospitals to engage in multidisciplinary collaborations preoperatively to try to improve LOS in this resource-intensive population.

  8. ARRANGEMENT FOR REPLACING FILTERS

    DOEpatents

    Blomgren, R.A.; Bohlin, N.J.C.

    1957-08-27

    An improved filtered air exhaust system which may be continually operated during the replacement of the filters without the escape of unfiltered air is described. This is accomplished by hermetically sealing the box like filter containers in a rectangular tunnel with neoprene covered sponge rubber sealing rings coated with a silicone impregnated pneumatic grease. The tunnel through which the filters are pushed is normal to the exhaust air duct. A number of unused filters are in line behind the filters in use, and are moved by a hydraulic ram so that a fresh filter is positioned in the air duct. The used filter is pushed into a waiting receptacle and is suitably disposed. This device permits a rapid and safe replacement of a radiation contaminated filter without interruption to the normal flow of exhaust air.

  9. Prevalence of previously undiagnosed abdominal aortic aneurysms in the area of Como: the ComoCuore "looking for AAA" ultrasonography screening.

    PubMed

    Corrado, Giovanni; Durante, Alessandro; Genchi, Vincenzo; Trabattoni, Loris; Beretta, Sandro; Rovelli, Enza; Foglia-Manzillo, Giovanni; Ferrari, Giovanni

    2016-08-01

    The prognosis for abdominal aortic aneurysm (AAA) rupture is poor. Long-term follow-up of population-based randomized trials has demonstrated that ultrasound (US) screening for abdominal aortic aneurysms (AAAs) measuring 3 cm or greater decreases AAA-related mortality rates and is cost-effective. We though to prospectively perform during a 26-month period a limited US examination of the infrarenal aorta in volunteers of both gender aged 60-85 years without history of AAA living in the area of Como, Italy. From September 2010 to November 2013 ComoCuore, a no-profit nongovernmental association, enrolled 1555 people (aged 68.8 ± 6.8 years; 48.6 % males). Clinical data and a US imaging of the aorta were collected for each participant. AAA was found in 22 volunteers (1.4 %) mainly males (2.5 % in males vs. 0.4 % in females p = 0.005). Overall, the prevalence of cardiovascular risk factors was higher in patients with vs. without AAA (mean 2.9 ± 3.0 vs. 1.4 ± 1.0 respectively, p < 0.0001). Independent predictors of AAA on multivariate analysis were age (OR 1.14, 1.06-1.22; p < 0.0001), male gender (OR 8.23, 1.79-37.91; p = 0.007), and both current (OR 4.98, 1.57-15.79; p = 0.007) and previous smoking (OR 2.76, 1.12-8.94; p = 0.03). Our study confirms the feasibility of one time US screening for AAA in a large cohort of asymptomatic people. Independent predictors of AAA were male sex, older age and a history of smoking. Accordingly to recent data the prevalence of AAA seems to be declining, maybe due to a reduction of smoking in Italy.

  10. Glaucoma after corneal replacement.

    PubMed

    Baltaziak, Monika; Chew, Hall F; Podbielski, Dominik W; Ahmed, Iqbal Ike K

    Glaucoma is a well-known complication after corneal transplantation surgery. Traditional corneal transplantation surgery, specifically penetrating keratoplasty, has been slowly replaced by the advent of new corneal transplantation procedures: primarily lamellar keratoplasties. There has also been an emergence of keratoprosthesis implants for eyes that are high risk of failure with penetrating keratoplasty. Consequently, there are different rates of glaucoma, pathogenesis, and potential treatment in the form of medical, laser, or surgical therapy. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Organosiloxane-grafted natural polymer coatings

    DOEpatents

    Sugama, Toshifumi

    1998-01-01

    A new family of polysaccharide graft polymers are provided as corrosion resistant coatings having antimicrobial properties which are useful on light metals such as aluminum, magnesium, zinc, steel and their alloys. Methods of making the polysaccharide graft polymers are also included. The methods of making the polysaccharide graft polymers involve reacting a polysaccharide source with an antimicrobial agent under conditions of hydrolysis-condensation.

  12. Cell culture-based tissue engineering as an alternative to bone grafts in implant dentistry: a literature review.

    PubMed

    Boeckel, Daniel Gonçalves; Shinkai, Rosemary Sadami Arai; Grossi, Márcio Lima; Teixeira, Eduardo Rolim

    2012-09-01

    Several biomaterials and techniques for bone grafting have been described in the literature for atresic bone tissue replacement caused by edentulism, surgical resectioning, and traumas. A new technique involves tissue engineering, a promising option to replace bone tissue and solve problems associated with morbidity of autogenous grafting. This literature review aims to describe tissue-engineering techniques using ex vivo cell culture as an alternative to repair bone maxillary atresias and discuss the concepts and potentials of bone regeneration through cell culture techniques as an option for restorative maxillofacial surgery.

  13. Polyether-polyester graft copolymer

    NASA Technical Reports Server (NTRS)

    Bell, Vernon L. (Inventor)

    1987-01-01

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

  14. A Comparative Study of the efficacy by using different stent-grafts in bell-bottom technique for the treatment of abdominal aortic aneurysm concomitant with iliac artery aneurysm.

    PubMed

    Wang, Lixin; Liang, Shuangchao; Xu, Xin; Chen, Bin; Jiang, Junhao; Shi, Zhenyu; Tang, Xiao; Zhou, Xiushi; Zhou, Min; Guo, Daqiao; Fu, Weiguo

    2018-06-06

    Bell-bottom technique (BBT) is one method to preserve the internal iliac artery during EVAR for abdominal aortic aneurysm(AAA) that extend to iliac artery. The data on the efficacy of this technique is still limited. We sought to evaluate the mid-term efficacy of BBT by using different stent-grafts in the treatment of AAA combined with iliac artery aneurysm (IAA). From January 2011 to December 2016, AAA patients with IAA using BBT to preserve the internal iliac artery were retrospectively analyzed in our institution. Patients were followed up at 3, 6 and then every 12 months after surgery. The outcomes among three types of stent-grafts (Zenith, Excluder and Endurant) were compared. BBT related endpoints including type Ib endoleak, IAA sac expansion, distal neck expansion and rupture during follow-up were compared. Other events including perioperative death, any other types of endoleak and corresponding management were also documented. A total of 125 patients with 141 IAAs were identified. Ninety-eight patients (78.4%) with 113 lesions (80.4%) received a median follow-up time of 38 months. The incidence of type Ib endoleak was 22.9%, 8.3%, 11.9% and 14.2% (P=0.19) in Zenith, Excluder, Endurant group and total patients respectively. The incidence of IAA sac enlargement was 17.1%, 5.6%, 7.1% and 9.7% (P=0.20). The incidence of IAA rupture was 8.6%, 0.0%, 0.0% and 2.7%(P=0.03). The incidence of IAA neck enlargement was 34.3%, 13.9%, 16.7% and 21.2%(P=0.07). Totally 14 cases (10.7%) received further treatment for BBT related issues. Although BBT remains a safe and effective treatment option to preserve internal iliac artery during standard EVAR with acceptable complication rates in Asians, different IAA rupture rates were found among three different stent-grafts. Our data first time revealed that the types of stent-grafts have influence on the final clinical outcome. Based on that, iliac extension should be selected appropriately while treating AAA-IAA. Copyright

  15. Impact of graft implantation order on graft survival in simultaneous pancreas-kidney transplantation.

    PubMed

    Niclauss, Nadja; Bédat, Benoît; Morel, Philippe; Andres, Axel; Toso, Christian; Berney, Thierry

    2016-05-01

    The optimal order of revascularization for pancreas and kidney grafts in simultaneous pancreas-kidney transplantation has not been established. In this study, we investigate the influence of graft implantation order on graft survival in SPK. 12 700 transplantations from the Scientific Registry of Transplant Recipients were analyzed retrospectively. Graft implantation order was determined based on the reported ischemia times of pancreas and kidney grafts. Pancreas and kidney graft survivals were analyzed depending on graft implantation order at 3 months and 5 years using Kaplan-Meier plots. Significance was tested with log-rank test and Cox regression model. In 8454 transplantations, the pancreas was implanted first (PBK), and in 4246 transplantations, the kidney was implanted first (KBP). The proportion of lost pancreas grafts at 3 months was significantly lower in PBK (9.4% vs. 10.8%, P = 0.011). Increasing time lag (>2 h) between kidney and pancreas graft implantation in KBP accentuated the detrimental impact on pancreas graft survival (12.5% graft loss at 3 months, P = 0.001). Technical failure rates were reduced in PBK (5.6 vs. 6.9%, P = 0.005). Graft implantation order had no impact on kidney graft survival. In summary, although observed differences are small, pancreas graft implantation first increases short-term pancreas graft survival and reduces rates of technical failure. © 2016 Steunstichting ESOT.

  16. Design of experiments in medical physics: Application to the AAA beam model validation.

    PubMed

    Dufreneix, S; Legrand, C; Di Bartolo, C; Bremaud, M; Mesgouez, J; Tiplica, T; Autret, D

    2017-09-01

    The purpose of this study is to evaluate the usefulness of the design of experiments in the analysis of multiparametric problems related to the quality assurance in radiotherapy. The main motivation is to use this statistical method to optimize the quality assurance processes in the validation of beam models. Considering the Varian Eclipse system, eight parameters with several levels were selected: energy, MLC, depth, X, Y 1 and Y 2 jaw dimensions, wedge and wedge jaw. A Taguchi table was used to define 72 validation tests. Measurements were conducted in water using a CC04 on a TrueBeam STx, a TrueBeam Tx, a Trilogy and a 2300IX accelerator matched by the vendor. Dose was computed using the AAA algorithm. The same raw data was used for all accelerators during the beam modelling. The mean difference between computed and measured doses was 0.1±0.5% for all beams and all accelerators with a maximum difference of 2.4% (under the 3% tolerance level). For all beams, the measured doses were within 0.6% for all accelerators. The energy was found to be an influencing parameter but the deviations observed were smaller than 1% and not considered clinically significant. Designs of experiment can help define the optimal measurement set to validate a beam model. The proposed method can be used to identify the prognostic factors of dose accuracy. The beam models were validated for the 4 accelerators which were found dosimetrically equivalent even though the accelerator characteristics differ. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  17. Phenotype–genotype spectrum of AAA syndrome from Western India and systematic review of literature

    PubMed Central

    Patt, Hiren; Koehler, Katrin; Lodha, Sailesh; Yerawar, Chaitanya; Huebner, Angela; Thakkar, Kunal; Arya, Sneha; Nair, Sandhya; Goroshi, Manjunath; Ganesh, Hosahithlu; Sarathi, Vijaya; Lila, Anurag; Bandgar, Tushar; Shah, Nalini

    2017-01-01

    Objective To study genotype–phenotype spectrum of triple A syndrome (TAS). Methods Retrospective chart analysis of Indian TAS patients (cohort 1, n = 8) and review of genotyped TAS cases reported in world literature (cohort 2, n = 133, 68 publications). Results Median age at presentation was 4.75 years (range: 4–10) and 5 years (range: 1–42) for cohorts 1 and 2, respectively. Alacrima, adrenal insufficiency (AI), achalasia and neurological dysfunction (ND) were seen in 8/8, 8/8, 7/8 and 4/8 patients in cohort 1, and in 99, 91, 93 and 79% patients in cohort 2, respectively. In both cohorts, alacrima was present since birth while AI and achalasia manifested before ND. Mineralocorticoid deficiency (MC) was uncommon (absent in cohort 1, 12.5% in cohort 2). In cohort 1, splice-site mutation in exon 1 (p.G14Vfs*45) was commonest, followed by a deletion in exon 8 (p.S255Vfs*36). Out of 65 mutations in cohort 2, 14 were recurrent and five exhibited regional clustering. AI was more prevalent, more often a presenting feature, and was diagnosed at younger age in T group (those with truncating mutations) as compared to NT (non-truncating mutations) group. ND was more prevalent, more common a presenting feature, with later age at onset in NT as compared to T group. Conclusion Clinical profile of our patients is similar to that of patients worldwide. Alacrima is the earliest and most consistent finding. MC deficiency is uncommon. Some recurrent mutations show regional clustering. p.G14Vfs*45 and p.S255Vfs*36 account for majority of AAAS mutations in our cohort. Phenotype of T group differs from that of NT group and merits future research. PMID:29180348

  18. Differential proteome analysis during early somatic embryogenesis in Musa spp. AAA cv. Grand Naine.

    PubMed

    Kumaravel, Marimuthu; Uma, Subbaraya; Backiyarani, Suthanthiram; Saraswathi, Marimuthu Somasundaram; Vaganan, Muthu Mayil; Muthusamy, Muthusamy; Sajith, Kallu Purayil

    2017-01-01

    Endogenous hormone secretion proteins along with stress and defense proteins play predominant role in banana embryogenesis. This study reveals the underlying molecular mechanism during transition from vegetative to embryogenic state. Banana (Musa spp.) is well known globally as a food fruit crop for millions. The requirement of quality planting material of banana is enormous. Although mass multiplication through tissue culture is in vogue, high-throughput techniques like somatic embryogenesis (SE) as a mass multiplication tool needs to be improved. Apart from clonal propagation, SE has extensive applications in genetic improvement and mutation. SE in banana is completely genome-dependent and most of the commercial cultivars exhibit recalcitrance. Thus, understanding the molecular basis of embryogenesis in Musa will help to develop strategies for mass production of quality planting material. In this study, differentially expressed proteins between embryogenic calli (EC) and non-embryogenic calli (NEC) with respect to the explant, immature male flower buds (IMFB), of cv. Grand Naine (AAA) were determined using two-dimensional gel electrophoresis (2DE). The 2DE results were validated through qRT-PCR. In total, 65 proteins were identified: 42 were highly expressed and 23 were less expressed in EC compared to NEC and IMFB. qRT-PCR analysis of five candidate proteins, upregulated in EC, were well correlated with expression at transcript level. Further analysis of proteins showed that embryogenesis in banana is associated with the control of oxidative stress. The regulation of ROS scavenging system and protection of protein structure occurred in the presence of heat shock proteins. Alongside, high accumulation of stress-related cationic peroxidase and plant growth hormone-related proteins like indole-3-pyruvate monooxygenase and adenylate isopentenyltransferase in EC revealed the association with the induction of SE.

  19. Replacement of the Thoracoabdominal Aorta after Endovascular Abdominal Aneurysm Repair for Ruptured Infected Aneurysm: A Case Report

    PubMed Central

    Kondo, Nobuo; Tamura, Kentaro; Sakaguchi, Taichi; Chikazawa, Genta; Yoshitaka, Hidenori

    2017-01-01

    A 73-year-old man underwent emergency endovascular abdominal aneurysm repair (EVAR) for a ruptured infected abdominal aortic aneurysm. Two years after EVAR, he was admitted with a spiking fever and left lower back pain. Computed tomography scan revealed not only recurrent graft infection with psoas abscess but also infection around the orifice of the superior mesenteric artery. Because conservative medical therapy with antibiotics could not control the infection, we performed complete removal of the infected stent graft, debridement of psoas abscess, and in situ replacement of the thoracoabdominal aorta using rifampicin-soaked prosthetic grafts, followed by the omental flap. He was discharged with no complications. PMID:29034025

  20. Posterior repair with perforated porcine dermal graft.

    PubMed

    Taylor, G Bernard; Moore, Robert D; Miklos, John R; Mattox, T Fleming

    2008-01-01

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

  1. Tubularized urethral replacement with unseeded matrices: what is the maximum distance for normal tissue regeneration?

    PubMed

    Dorin, Ryan P; Pohl, Hans G; De Filippo, Roger E; Yoo, James J; Atala, Anthony

    2008-08-01

    Complete urethral replacement using unseeded matrices has been proposed as a possible therapy in cases of congenital or acquired anomalies producing significant defects. Tissue regeneration involves fibrin deposition, re-epithelialization, and remodeling that are limited by the size of the defect. Scar formation occurs because of an inability of native cells to regenerate over the defect before fibrosis takes place. We investigated the maximum potential distance of normal native tissue regeneration over a range of distances using acellular matrices for tubular grafts as an experimental model. Tubularized urethroplasties were performed in 12 male rabbits using acellular matrices of bladder submucosa at varying lengths (0.5, 1, 2, and 3 cm). Serial urethrography was performed at 1, 3, and 4 weeks. Animals were sacrificed at 1, 3, and 4 weeks and the grafts harvested. Urothelial and smooth muscle cell regeneration was documented histologically with H&E and Masson's trichrome stains. Urethrograms demonstrated normal urethral calibers in the 0.5 cm group at all time points. The evolution of a stricture was demonstrated in the 1, 2, and 3 cm grafts by 4 weeks. Histologically all grafts demonstrated ingrowth of urothelial cells from the anastomotic sites at 1 week. By 4 weeks, the 0.5 cm grafts had a normal transitional layer of epithelium surrounded by a layer of muscle within the wall of the urethral lumen. The 1, 2, and 3 cm grafts showed ingrowth and normal cellular regeneration only at the anastomotic edges with increased collagen deposition and fibrosis toward the center by 2 weeks, and dense fibrin deposition throughout the grafts by 4 weeks. The maximum defect distance suitable for normal tissue formation using acellular grafts that rely on the native cells for tissue regeneration appears to be 0.5 cm. The indications for the use of acellular matrices in tubularized grafts may therefore be limited by the size of the defect to be repaired.

  2. Microporous pure beta-tricalcium phosphate implants for press-fit fixation of anterior cruciate ligament grafts: strength and healing in a sheep model.

    PubMed

    Mayr, Hermann O; Dietrich, Markwart; Fraedrich, Franz; Hube, Robert; Nerlich, Andreas; von Eisenhart-Rothe, Rüdiger; Hein, Werner; Bernstein, Anke

    2009-09-01

    A sheep study was conducted to test a press-fit technique using microporous pure beta-tricalcium phosphate (beta-TCP) dowels for fixation of the anterior cruciate ligament (ACL) graft. Microporous (5 mum) cylindrical plugs of beta-TCP (diameter, 7 mm; length, 25 mm) with interconnecting pores were used. The material featured a novel configuration of structure and surface geometry. Implants were tested by use of press-fit fixation of ACL grafts with and without bone blocks in 42 sheep over a period of 24 weeks. Biomechanical, radiologic, histologic, and immunohistochemical evaluations were performed. In load-to-failure tests at 6, 12, and 24 weeks after surgery, the intra-articular graft always failed, not the fixation. Grafts showed bony fixation in the tunnel at 6 weeks and primary healing at the junction of the tunnel and joint after 24 weeks. Tricalcium phosphate was resorbed and simultaneously replaced by bone. Remodeling was still incomplete at 24 weeks. In the sheep model microporous beta-TCP implants used with press-fit fixation of ACL grafts permit early functional rehabilitation. After 6 weeks, the graft is fixed by woven bone or bony integration. Implanted microporous tricalcium phosphate is resorbed and replaced by bone. In a sheep model we showed that primary healing of ACL grafts with resorption and bony replacement of the fixating implant can be achieved by means of press-fit fixation with pure beta-TCP.

  3. Power Plant Replacement Study

    SciTech Connect

    Reed, Gary

    2010-09-30

    This report represents the final report for the Eastern Illinois University power plant replacement study. It contains all related documentation from consideration of possible solutions to the final recommended option. Included are the economic justifications associated with the chosen solution along with application for environmental permitting for the selected project for construction. This final report will summarize the results of execution of an EPC (energy performance contract) investment grade audit (IGA) which lead to an energy services agreement (ESA). The project includes scope of work to design and install energy conservation measures which are guaranteed by the contractor to bemore » self-funding over its twenty year contract duration. The cost recovery is derived from systems performance improvements leading to energy savings. The prime focus of this EPC effort is to provide a replacement solution for Eastern Illinois University’s aging and failing circa 1925 central steam production plant. Twenty-three ECMs were considered viable whose net impact will provide sufficient savings to successfully support the overall project objectives.« less

  4. Total Knee Replacement

    PubMed Central

    2005-01-01

    Executive Summary Objective The aim of this review was to assess the effectiveness, in terms of pain reduction and functional improvement, and costing of total knee replacement (TKR) for people with osteoarthritis for whom less invasive treatments (such as physiotherapy, analgesics, anti-inflammatory drugs, intra-articular steroids, hyaluronic acids, and arthroscopic surgery) have failed. Clinical Need Osteoarthritis affects an estimated 10% to 12% of Canadian adults. The therapeutic goals of osteoarthritis treatment are to improve joint mobility and reduce pain. Stepwise treatment options include exercise, weight loss, physiotherapy, analgesics, anti-inflammatory drugs, intra-articular steroids and hyaluronic acids, arthroscopic surgery, and, in severe cases, total joint replacement with follow-up rehabilitation. These treatments are delivered by a range of health care professionals, including physiotherapists, occupational therapists, family physicians, internists, rheumatologists, and orthopedic surgeons. TKR is an end-of-line treatment for patients with severe pain and functional limitations. More women than men undergo knee replacement, and most patients are between 55 and 84 years old. The Technology TKR is a surgical procedure in which an artificial joint or prosthesis replaces a damaged knee joint. The primary indication for TKR is pain, followed by functional limitation. Usually, a person’s daily activities must be substantially affected by pain and functional limitations for him or her to be considered a candidate for TKR. There are 3 different types of knee replacement prostheses. Non-constrained prostheses use the patient’s ligaments and muscles to provide the stability for the prosthesis. Semi-constrained prostheses provide some stability for the knee and do not rely entirely on the patient’s ligaments and muscles to provide the stability. Constrained prostheses are for patients whose ligaments and muscles are not able to provide stability for

  5. Cadmium plating replacements

    NASA Technical Reports Server (NTRS)

    Nelson, Mary J.; Groshart, Earl C.

    1995-01-01

    The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating.

  6. Evaluation of the dose calculation accuracy for small fields defined by jaw or MLC for AAA and Acuros XB algorithms.

    PubMed

    Fogliata, Antonella; Lobefalo, Francesca; Reggiori, Giacomo; Stravato, Antonella; Tomatis, Stefano; Scorsetti, Marta; Cozzi, Luca

    2016-10-01

    Small field measurements are challenging, due to the physical characteristics coming from the lack of charged particle equilibrium, the partial occlusion of the finite radiation source, and to the detector response. These characteristics can be modeled in the dose calculations in the treatment planning systems. Aim of the present work is to evaluate the MU calculation accuracy for small fields, defined by jaw or MLC, for anisotropic analytical algorithm (AAA) and Acuros XB algorithms, relative to output measurements on the beam central axis. Single point output factor measurement was acquired with a PTW microDiamond detector for 6 MV, 6 and 10 MV unflattened beams generated by a Varian TrueBeam STx equipped with high definition-MLC. Fields defined by jaw or MLC apertures were set; jaw-defined: 0.6 × 0.6, 0.8 × 0.8, 1 × 1, 2 × 2, 3 × 3, 4 × 4, 5 × 5, and 10 × 10 cm 2 ; MLC-defined: 0.5 × 0.5 cm 2 to the maximum field defined by the jaw, with 0.5 cm stepping, and jaws set to: 2 × 2, 3 × 3, 4 × 4, 5 × 5, and 10 × 10 cm 2 . MU calculation was obtained with 1 mm grid in a virtual water phantom for the same fields, for AAA and Acuros algorithms implemented in the Varian eclipse treatment planning system (version 13.6). Configuration parameters as the effective spot size (ESS) and the dosimetric leaf gap (DLG) were varied to find the best parameter setting. Differences between calculated and measured doses were analyzed. Agreement better than 0.5% was found for field sizes equal to or larger than 2 × 2 cm 2 for both algorithms. A dose overestimation was present for smaller jaw-defined fields, with the best agreement, averaged over all the energies, of 1.6% and 4.6% for a 1 × 1 cm 2 field calculated by AAA and Acuros, respectively, for a configuration with ESS = 1 mm for both X and Y directions for AAA, and ESS = 1.5 and 0 mm for X and Y directions for Acuros. Conversely, a calculated dose underestimation was found for small MLC-defined fields, with the

  7. Surgical Outcomes of Porcine Acellular Dermis Graft in Anophthalmic Socket: Comparison with Oral Mucosa Graft.

    PubMed

    Teo, Livia; Woo, Young Jun; Kim, Dong Kyu; Kim, Chang Yeom; Yoon, Jin Sook

    2017-02-01

    We describe our experience with the Permacol graft in anophthalmic socket reconstruction, and compare it to the autologous buccal mucosal graft, emphasizing the postoperative vascularization and contraction of each graft. This was a retrospective comparative study. We measured the time necessary for the graft surface to be completely vascularized, as well as the fornix depth of the conjunctival sac in anophthalmic patients. Ten patients underwent Permacol graft reconstruction, with 44 undergoing buccal mucosal graft reconstruction. Seven eyelids (70%) in the Permacol group had a good outcome, with improvement in lower eyelid position and prosthesis retention. Nine out of 10 eyelids (90%) in this group showed complete vascularization of the graft at 2.6 ± 1.9 months postoperatively, while the grafted buccal mucosa was fully vascularized at 1.1 ± 0.3 months postoperatively ( p < 0.01). Postoperative fornix depth in the Permacol group was 9.1 ± 2.2 mm, compared to 14.9 ± 4.5 mm in the buccal mucosal graft group ( p < 0.01). Mean increases in fornix depth were 33.1% and 67.9% of the mean vertical length of the implanted graft. The Permacol graft can be useful as spacer graft material in anophthalmic socket patients. It takes longer to vascularize, and undergoes greater graft shrinkage with time, compared to the buccal mucosal graft.

  8. m-AAA Complexes Are Not Crucial for the Survival of Arabidopsis Under Optimal Growth Conditions Despite Their Importance for Mitochondrial Translation.

    PubMed

    Kolodziejczak, Marta; Skibior-Blaszczyk, Renata; Janska, Hanna

    2018-05-01

    For optimal mitochondrial activity, the mitochondrial proteome must be properly maintained or altered in response to developmental and environmental stimuli. Based on studies of yeast and humans, one of the key players in this control are m-AAA proteases, mitochondrial inner membrane-bound ATP-dependent metalloenzymes. This study focuses on the importance of m-AAA proteases in plant mitochondria, providing their first experimentally proven physiological substrate. We found that the Arabidopsis m- AAA complexes composed of AtFTSH3 and/or AtFTSH10 are involved in the proteolytic maturation of ribosomal subunit L32. Consequently, in the double Arabidopsis ftsh3/10 mutant, mitoribosome biogenesis, mitochondrial translation and functionality of OXPHOS (oxidative phosphorylation) complexes are impaired. However, in contrast to their mammalian or yeast counterparts, plant m-AAA complexes are not critical for the survival of Arabidopsis under optimal conditions; ftsh3/10 plants are only slightly smaller in size at the early developmental stage compared with plants containing m-AAA complexes. Our data suggest that a lack of significant visible morphological alterations under optimal growth conditions involves mechanisms which rely on existing functional redundancy and induced functional compensation in Arabidopsis mitochondria.

  9. A dosimetric evaluation of the Eclipse AAA algorithm and Millennium 120 MLC for cranial intensity-modulated radiosurgery

    SciTech Connect

    Calvo Ortega, Juan Francisco, E-mail: jfcdrr@yahoo.es; Moragues, Sandra; Pozo, Miquel

    2014-07-01

    The aim of this study is to assess the accuracy of a convolution-based algorithm (anisotropic analytical algorithm [AAA]) implemented in the Eclipse planning system for intensity-modulated radiosurgery (IMRS) planning of small cranial targets by using a 5-mm leaf-width multileaf collimator (MLC). Overall, 24 patient-based IMRS plans for cranial lesions of variable size (0.3 to 15.1 cc) were planned (Eclipse, AAA, version 10.0.28) using fixed field-based IMRS produced by a Varian linear accelerator equipped with a 120 MLC (5-mm width on central leaves). Plan accuracy was evaluated according to phantom-based measurements performed with radiochromic film (EBT2, ISP, Wayne, NJ). Film 2Dmore » dose distributions were performed with the FilmQA Pro software (version 2011, Ashland, OH) by using the triple-channel dosimetry method. Comparison between computed and measured 2D dose distributions was performed using the gamma method (3%/1 mm). Performance of the MLC was checked by inspection of the DynaLog files created by the linear accelerator during the delivery of each dynamic field. The absolute difference between the calculated and measured isocenter doses for all the IMRS plans was 2.5% ± 2.1%. The gamma evaluation method resulted in high average passing rates of 98.9% ± 1.4% (red channel) and 98.9% ± 1.5% (blue and green channels). DynaLog file analysis revealed a maximum root mean square error of 0.46 mm. According to our results, we conclude that the Eclipse/AAA algorithm provides accurate cranial IMRS dose distributions that may be accurately delivered by a Varian linac equipped with a Millennium 120 MLC.« less

  10. Nanomechanical and thermophoretic analyses of the nucleotide-dependent interactions between the AAA + subunits of magnesium chelatase

    DOE PAGES

    Adams, Nathan B. P.; Vasilev, Cvetelin; Brindley, Amanda A.; ...

    2016-04-30

    In chlorophyll biosynthesis, the magnesium chelatase enzyme complex catalyzes the insertion of a Mg 2+ ion into protoporphyrin IX. Prior to this event, two of the three subunits, the AAA + proteins ChlI and ChlD, form a ChlID–MgATP complex. We used microscale thermophoresis to directly determine dissociation constants for the I-D subunits from Synechocystis, and to show that the formation of a ChlID–MgADP complex, mediated by the arginine finger and the sensor II domain on ChlD, is necessary for the assembly of the catalytically active ChlHID–MgATP complex. The N-terminal AAA + domain of ChlD is essential for complex formation, butmore » some stability is preserved in the absence of the C-terminal integrin domain of ChlD, particularly if the intervening polyproline linker region is retained. Single molecule force spectroscopy (SMFS) was used to determine the factors that stabilize formation of the ChlID–MgADP complex at the single molecule level; ChlD was attached to an atomic force microscope (AFM) probe in two different orientations, and the ChlI subunits were tethered to a silica surface; the probability of subunits interacting more than doubled in the presence of MgADP, and we show that the N-terminal AAA + domain of ChlD mediates this process, in agreement with the microscale thermophoresis data. Analysis of the unbinding data revealed a most probable interaction force of around 109 pN for formation of single ChlID–MgADP complexes. Finally, these experiments provide a quantitative basis for understanding the assembly and function of the Mg chelatase complex.« less

  11. Morphology-related limitations of EVAR applicability in the treatment of AAA in West-Central Poland.

    PubMed

    Dzieciuchowicz, Łukasz; Tomczak, Jolanta; Strauss, Ewa; Oszkinis, Grzegorz

    2018-05-14

    To analyze the current applicability of endovascular aneurysm repair (EVAR) in patients with an infrarenal abdominal aortic aneurysm (AAAs) with indication for elective treatment in West-Central Poland. Computed tomography angiograms of 100 consecutive patients with infrarenal AAA deemed to require treatment were analyzed with an OsiriX DICOM viewer in 3D-MPR mode. Proximal neck diameter, length, angulation, shape, the presence of thrombus and calcification, distal neck diameter, and morphology of the iliac arteries were determined. Three sets of morphological criteria were established. The optimal criteria consisted of a non-conical proximal neck without moderate or severe calcification or thrombus, with a diameter of 18-28 mm, length of ≥15 mm, and β angulation of <60%; a distal neck with a diameter of ≥20 mm; a landing zone in the common iliac arteries with a length of ≥ 10 mm and diameter of ≤ 20 mm; and external iliac arteries with diameters of ≥7 mm. The suboptimal criteria included proximal neck diameters of 18-32 mm, neck lengths ≥10 mm, infrarenal neck angulations of up to 75˚, and common iliac artery diameters of up to 25 mm. Finally, the extended suboptimal criteria included proximal neck diameters of 16-34 mm and infrarenal neck angulations ≤90˚, without limits in the maximal diameter of the common iliac arteries. The median maximum aneurysm diameter was 61 mm. The optimal, suboptimal, and extended suboptimal criteria were met by 23%, 32%, and 53% of patients, respectively. The most common deviations were wide, conical, and angulated proximal necks and aneurysmal iliac arteries. The majority of patients with AAA deemed to be candidates for elective repair do not meet the most favorable criteria for EVAR. Availability of better endovascular solutions for conical, angulated, and wide necks and aneurysmal iliac arteries would likely expand EVAR applicability. Open repair remains a valid option. Copyright © 2018 Elsevier Inc. All rights

  12. Antenna grout replacement system

    NASA Technical Reports Server (NTRS)

    Mcclung, C. E. (Inventor)

    1983-01-01

    An epoxy grout suitable for use in mounting and positioning bearing runner plates used in hydrostatic bearing assemblies for rotatably mounting large radio telescope structures to stationary support pedestals is described. The epoxy grout may be used in original mountings or may be used as part of a replacement system for repairing cavities in existing grout resulting from grout deterioration. The epoxy grout has a relatively short work life and cure time even in the presence of hydraulic oil. The epoxy grout cures without shrinking or sagging to form a grout which is sufficiently strong and durable to provide a grout especially well suited for use under the high pressure loading and close tolerance requirements of large hydrostatic bearing assemblies.

  13. Aerocoat 7 Replacement Coatings

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Kennedy Space Center has used Aerocoat 7 (AR-7) to protect stainless-steel flex hoses at Launch Complex (LC-39) and hydraulic lines of the Mobile Launcher Platform (MLP) because it provides excellent corrosion protection in low-temperature applications. The Sovereign Company produced AR-7 exclusively for NASA but discontinued production because the coating released high levels of volatile organic compounds (VOCs) and had a significant environmental impact. The purpose of this project was to select and evaluate potential replacement coatings for AR-7 that would be more environmentally sound. The physical and mechanical properties of commercially available coatings were investigated through the Internet. The ideal coating would be fluid enough to penetrate the outer mesh of a stainless-steel flex hose and coat the inner hose, and flexible enough to withstand the movement of the hose, as well as the expansion and contraction of its metal caused by changes in temperature.

  14. Replace with abstract title

    NASA Astrophysics Data System (ADS)

    Coho, Aleksander; Kioussis, Nicholas

    2003-03-01

    We use the semidiscrete variational generelized Peierls-Nabarro model to study the effect of Cu alloying on the dislocation properties of Al. First-principles density functional theory (DFT) is used to calculate the generalized-stacking-fault (GSF) energy surface when a <111> plane, on which one in four Al atoms has been replaced with a Cu atom, slips over a pure Al <111> plane. Various dislocation core properties (core width, energy, Peierls stress, dissociation tendency) are investigated and compared with the pure Al case. Cu alloying lowers the intrinsic stacking fault (ISF) energy, which makes dislocations more likely to dissociate into partials. We also try to understand the lowering of ISF energy in terms of Al-Cu and Al-Al bond formation and braking during shearing along the <112> direction. From the above we draw conclusions about the effects of Cu alloying on the mechanical properties of Al.

  15. [Autologous fat grafting in children].

    PubMed

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

    2016-10-01

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

  16. Developmental Localization and Methylesterification of Pectin Epitopes during Somatic Embryogenesis of Banana (Musa spp. AAA)

    PubMed Central

    Xu, Chunxiang; Zhao, Lu; Pan, Xiao; Šamaj, Jozef

    2011-01-01

    Background The plant cell walls play an important role in somatic embryogenesis and plant development. Pectins are major chemical components of primary cell walls while homogalacturonan (HG) is the most abundant pectin polysaccharide. Developmental regulation of HG methyl-esterification degree is important for cell adhesion, division and expansion, and in general for proper organ and plant development. Methodology/Principal Findings Developmental localization of pectic homogalacturonan (HG) epitopes and the (1→4)-β-D-galactan epitope of rhamnogalacturonan I (RG-I) and degree of pectin methyl-esterification (DM) were studied during somatic embryogenesis of banana (Musa spp. AAA). Histological analysis documented all major developmental stages including embryogenic cells (ECs), pre-globular, globular, pear-shaped and cotyledonary somatic embryos. Histochemical staining of extracellularly secreted pectins with ruthenium red showed the most intense staining at the surface of pre-globular, globular and pear-shaped somatic embryos. Biochemical analysis revealed developmental regulation of galacturonic acid content and DM in diverse embryogenic stages. Immunodots and immunolabeling on tissue sections revealed developmental regulation of highly methyl-esterified HG epitopes recognized by JIM7 and LM20 antibodies during somatic embryogenesis. Cell walls of pre-globular/globular and late-stage embryos contained both low methyl-esterified HG epitopes as well as partially and highly methyl-esterified ones. Extracellular matrix which covered surface of early developing embryos contained pectin epitopes recognized by 2F4, LM18, JIM5, JIM7 and LM5 antibodies. De-esterification of cell wall pectins by NaOH caused a decrease or an elimination of immunolabeling in the case of highly methyl-esterified HG epitopes. However, immunolabeling of some low methyl-esterified epitopes appeared stronger after this base treatment. Conclusions/Significance These data suggest that both low

  17. [Re-operation for Saccular Aneurysm after Ascending Aortic Replacement with Homograft;Report of a Case].

    PubMed

    Ikeda, Masahiro; Asakura, Toshihisa; Uwabe, Kazuhiko; Morita, Kozo; Iguchi, Atsushi; Niinami, Hiroshi

    2017-09-01

    A 62-years-old female had undergone ascending aortic replacement with homograft for graft infection and mediastinitis after initial replacement of ascending aorta due to acute type A dissection. Ten years after homograft replacement, follow up computed tomography showed acute growing saccular aneurysm of the homograft without infectious symptoms. We urgently performed Bentall procedure and hemiarch replacement successfully. Pathological diagnosis was true aneurysm of the homograft. She was discharged from hospital without any complication and has been quite uneventful 7 years after surgery. True aneurysm of the homograft is very rare and our case is the 1st report of successful reoperation.

  18. Preferences of AAA/AAG codon recognition by modified nucleosides, τm5s2U34 and t6A37 present in tRNALys.

    PubMed

    Sonawane, Kailas D; Kamble, Asmita S; Fandilolu, Prayagraj M

    2017-12-27

    Deficiency of 5-taurinomethyl-2-thiouridine, τm 5 s 2 U at the 34th 'wobble' position in tRNA Lys causes MERRF (Myoclonic Epilepsy with Ragged Red Fibers), a neuromuscular disease. This modified nucleoside of mt tRNA Lys , recognizes AAA/AAG codons during protein biosynthesis process. Its preference to identify cognate codons has not been studied at the atomic level. Hence, multiple MD simulations of various molecular models of anticodon stem loop (ASL) of mt tRNA Lys in presence and absence of τm 5 s 2 U 34 and N 6 -threonylcarbamoyl adenosine (t 6 A 37 ) along with AAA and AAG codons have been accomplished. Additional four MD simulations of multiple ASL mt tRNA Lys models in the context of ribosomal A-site residues have also been performed to investigate the role of A-site in recognition of AAA/AAG codons. MD simulation results show that, ASL models in presence of τm 5 s 2 U 34 and t 6 A 37 with codons AAA/AAG are more stable than the ASL lacking these modified bases. MD trajectories suggest that τm 5 s 2 U recognizes the codons initially by 'wobble' hydrogen bonding interactions, and then tRNA Lys might leave the explicit codon by a novel 'single' hydrogen bonding interaction in order to run the protein biosynthesis process smoothly. We propose this model as the 'Foot-Step Model' for codon recognition, in which the single hydrogen bond plays a crucial role. MD simulation results suggest that, tRNA Lys with τm 5 s 2 U and t 6 A recognizes AAA codon more preferably than AAG. Thus, these results reveal the consequences of τm 5 s 2 U and t 6 A in recognition of AAA/AAG codons in mitochondrial disease, MERRF.

  19. Bypass grafting to the anterior tibial artery.

    PubMed

    Armour, R H

    1976-01-01

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

  20. Vascularized bone graft for scaphoid nonunions.

    PubMed

    Mih, Alexander D

    2004-09-01

    Scaphoid fracture nonunion remains a challenging problem that may persist despite traditional methods of bone grafting and internal fixation. The alteration of wrist mechanics created by nonunion as well as the development of avascular necrosis leads to degenerative change of the radiocarpal joint accompanied by loss of motion and pain. The use of a vascularized bone graft has the theoretical benefit of increased blood flow that exceeds that of nonvascularized grafts. Numerous sources of vascularized bone graft have been described, including those from remote sites as well as from the carpus and distal radius. Knowledge of the blood supply to the distal radius has allowed for development of several vascularized bone graft harvest sites. The results of vascularized bone grafting from the distal radius have been encouraging, with numerous authors reporting the successful treatment of scaphoid nonunions.

  1. The role of plant hormones during grafting.

    PubMed

    Nanda, Amrit K; Melnyk, Charles W

    2018-01-01

    For millennia, people have cut and joined different plant tissues together through a process known as grafting. By creating a chimeric organism, desirable properties from two plants combine to enhance disease resistance, abiotic stress tolerance, vigour or facilitate the asexual propagation of plants. In addition, grafting has been extremely informative in science for studying and identifying the long-distance movement of molecules. Despite its increasing use in horticulture and science, how plants undertake the process of grafting remains elusive. Here, we discuss specifically the role of eight major plant hormones during the wound healing and vascular formation process, two phenomena involved in grafting. We furthermore present the roles of these hormones during graft formation and highlight knowledge gaps and future areas of interest for the field of grafting biology.

  2. The I domain of the AAA+ HslUV protease coordinates substrate binding, ATP hydrolysis, and protein degradation

    PubMed Central

    Sundar, Shankar; Baker, Tania A; Sauer, Robert T

    2012-01-01

    In the AAA+ HslUV protease, substrates are bound and unfolded by a ring hexamer of HslU, before translocation through an axial pore and into the HslV degradation chamber. Here, we show that the N-terminal residues of an Arc substrate initially bind in the HslU axial pore, with key contacts mediated by a pore loop that is highly conserved in all AAA+ unfoldases. Disordered loops from the six intermediate domains of the HslU hexamer project into a funnel-shaped cavity above the pore and are positioned to contact protein substrates. Mutations in these I-domain loops increase KM and decrease Vmax for degradation, increase the mobility of bound substrates, and prevent substrate stimulation of ATP hydrolysis. HslU-ΔI has negligible ATPase activity. Thus, the I domain plays an active role in coordinating substrate binding, ATP hydrolysis, and protein degradation by the HslUV proteolytic machine. PMID:22102327

  3. Unfolding the mechanism of the AAA+ unfoldase VAT by a combined cryo-EM, solution NMR study

    PubMed Central

    Huang, Rui; Ripstein, Zev A.; Augustyniak, Rafal; Lazniewski, Michal; Ginalski, Krzysztof; Kay, Lewis E.; Rubinstein, John L.

    2016-01-01

    The AAA+ (ATPases associated with a variety of cellular activities) enzymes play critical roles in a variety of homeostatic processes in all kingdoms of life. Valosin-containing protein-like ATPase of Thermoplasma acidophilum (VAT), the archaeal homolog of the ubiquitous AAA+ protein Cdc48/p97, functions in concert with the 20S proteasome by unfolding substrates and passing them on for degradation. Here, we present electron cryomicroscopy (cryo-EM) maps showing that VAT undergoes large conformational rearrangements during its ATP hydrolysis cycle that differ dramatically from the conformational states observed for Cdc48/p97. We validate key features of the model with biochemical and solution methyl-transverse relaxation optimized spectroscopY (TROSY) NMR experiments and suggest a mechanism for coupling the energy of nucleotide hydrolysis to substrate unfolding. These findings illustrate the unique complementarity between cryo-EM and solution NMR for studies of molecular machines, showing that the structural properties of VAT, as well as the population distributions of conformers, are similar in the frozen specimens used for cryo-EM and in the solution phase where NMR spectra are recorded. PMID:27402735

  4. Unfolding the mechanism of the AAA+ unfoldase VAT by a combined cryo-EM, solution NMR study.

    PubMed

    Huang, Rui; Ripstein, Zev A; Augustyniak, Rafal; Lazniewski, Michal; Ginalski, Krzysztof; Kay, Lewis E; Rubinstein, John L

    2016-07-19

    The AAA+ (ATPases associated with a variety of cellular activities) enzymes play critical roles in a variety of homeostatic processes in all kingdoms of life. Valosin-containing protein-like ATPase of Thermoplasma acidophilum (VAT), the archaeal homolog of the ubiquitous AAA+ protein Cdc48/p97, functions in concert with the 20S proteasome by unfolding substrates and passing them on for degradation. Here, we present electron cryomicroscopy (cryo-EM) maps showing that VAT undergoes large conformational rearrangements during its ATP hydrolysis cycle that differ dramatically from the conformational states observed for Cdc48/p97. We validate key features of the model with biochemical and solution methyl-transverse relaxation optimized spectroscopY (TROSY) NMR experiments and suggest a mechanism for coupling the energy of nucleotide hydrolysis to substrate unfolding. These findings illustrate the unique complementarity between cryo-EM and solution NMR for studies of molecular machines, showing that the structural properties of VAT, as well as the population distributions of conformers, are similar in the frozen specimens used for cryo-EM and in the solution phase where NMR spectra are recorded.

  5. An AAA Motor-Driven Mechanical Switch in Rpn11 Controls Deubiquitination at the 26S Proteasome.

    PubMed

    Worden, Evan J; Dong, Ken C; Martin, Andreas

    2017-09-07

    Poly-ubiquitin chains direct protein substrates to the 26S proteasome, where they are removed by the deubiquitinase Rpn11 during ATP-dependent substrate degradation. Rapid deubiquitination is required for efficient degradation but must be restricted to committed substrates that are engaged with the ATPase motor to prevent premature ubiquitin chain removal and substrate escape. Here we reveal the ubiquitin-bound structure of Rpn11 from S. cerevisiae and the mechanisms for mechanochemical coupling of substrate degradation and deubiquitination. Ubiquitin binding induces a conformational switch of Rpn11's Insert-1 loop from an inactive closed state to an active β hairpin. This switch is rate-limiting for deubiquitination and strongly accelerated by mechanical substrate translocation into the AAA+ motor. Deubiquitination by Rpn11 and ubiquitin unfolding by the ATPases are in direct competition. The AAA+ motor-driven acceleration of Rpn11 is therefore important to ensure that poly-ubiquitin chains are removed only from committed substrates and fast enough to prevent their co-degradation. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. The AAA+ proteins Pontin and Reptin enter adult age: from understanding their basic biology to the identification of selective inhibitors

    PubMed Central

    Matias, Pedro M.; Baek, Sung Hee; Bandeiras, Tiago M.; Dutta, Anindya; Houry, Walid A.; Llorca, Oscar; Rosenbaum, Jean

    2015-01-01

    Pontin and Reptin are related partner proteins belonging to the AAA+ (ATPases Associated with various cellular Activities) family. They are implicated in multiple and seemingly unrelated processes encompassing the regulation of gene transcription, the remodeling of chromatin, DNA damage sensing and repair, and the assembly of protein and ribonucleoprotein complexes, among others. The 2nd International Workshop on Pontin and Reptin took place at the Instituto de Tecnologia Química e Biológica António Xavier in Oeiras, Portugal on October 10–12, 2014, and reported significant new advances on the mechanisms of action of these two AAA+ ATPases. The major points under discussion were related to the mechanisms through which these proteins regulate gene transcription, their roles as co-chaperones, and their involvement in pathophysiology, especially in cancer and ciliary biology and disease. Finally, they may become anticancer drug targets since small chemical inhibitors were shown to produce anti-tumor effects in animal models. PMID:25988184

  7. The AAA+ proteins Pontin and Reptin enter adult age: from understanding their basic biology to the identification of selective inhibitors.

    PubMed

    Matias, Pedro M; Baek, Sung Hee; Bandeiras, Tiago M; Dutta, Anindya; Houry, Walid A; Llorca, Oscar; Rosenbaum, Jean

    2015-01-01

    Pontin and Reptin are related partner proteins belonging to the AAA+ (ATPases Associated with various cellular Activities) family. They are implicated in multiple and seemingly unrelated processes encompassing the regulation of gene transcription, the remodeling of chromatin, DNA damage sensing and repair, and the assembly of protein and ribonucleoprotein complexes, among others. The 2nd International Workshop on Pontin and Reptin took place at the Instituto de Tecnologia Química e Biológica António Xavier in Oeiras, Portugal on October 10-12, 2014, and reported significant new advances on the mechanisms of action of these two AAA+ ATPases. The major points under discussion were related to the mechanisms through which these proteins regulate gene transcription, their roles as co-chaperones, and their involvement in pathophysiology, especially in cancer and ciliary biology and disease. Finally, they may become anticancer drug targets since small chemical inhibitors were shown to produce anti-tumor effects in animal models.

  8. Cotranslocational processing of the protein substrate calmodulin by an AAA+ unfoldase occurs via unfolding and refolding intermediates.

    PubMed

    Augustyniak, Rafal; Kay, Lewis E

    2018-05-22

    Protein remodeling by AAA+ enzymes is central for maintaining proteostasis in a living cell. However, a detailed structural description of how this is accomplished at the level of the substrate molecules that are acted upon is lacking. Here, we combine chemical cross-linking and methyl transverse relaxation-optimized NMR spectroscopy to study, at atomic resolution, the stepwise unfolding and subsequent refolding of the two-domain substrate calmodulin by the VAT AAA+ unfoldase from Thermoplasma acidophilum By engineering intermolecular disulphide bridges between the substrate and VAT we trap the substrate at different stages of translocation, allowing structural studies throughout the translocation process. Our results show that VAT initiates substrate translocation by pulling on intrinsically unstructured N or C termini of substrate molecules without showing specificity for a particular amino acid sequence. Although the B1 domain of protein G is shown to unfold cooperatively, translocation of calmodulin leads to the formation of intermediates, and these differ on an individual domain level in a manner that depends on whether pulling is from the N or C terminus. The approach presented generates an atomic resolution picture of substrate unfolding and subsequent refolding by unfoldases that can be quite different from results obtained via in vitro denaturation experiments.

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

    PubMed

    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.

  10. Model for Estimating the Threshold Mechanical Stability of Structural Cartilage Grafts Used in Rhinoplasty

    PubMed Central

    Zemek, Allison; Garg, Rohit; Wong, Brian J. F.

    2014-01-01

    Objectives/Hypothesis Characterizing the mechanical properties of structural cartilage grafts used in rhinoplasty is valuable because softer engineered tissues are more time- and cost-efficient to manufacture. The aim of this study is to quantitatively identify the threshold mechanical stability (e.g., Young’s modulus) of columellar, L-strut, and alar cartilage replacement grafts. Study Design Descriptive, focus group survey. Methods Ten mechanical phantoms of identical size (5 × 20 × 2.3 mm) and varying stiffness (0.360 to 0.85 MPa in 0.05 MPa increments) were made from urethane. A focus group of experienced rhinoplasty surgeons (n = 25, 5 to 30 years in practice) were asked to arrange the phantoms in order of increasing stiffness. Then, they were asked to identify the minimum acceptable stiffness that would still result in favorable surgical outcomes for three clinical applications: columellar, L-strut, and lateral crural replacement grafts. Available surgeons were tested again after 1 week to evaluate intra-rater consistency. Results For each surgeon, the threshold stiffness for each clinical application differed from the threshold values derived by logistic regression by no more than 0.05 MPa (accuracy to within 10%). Specific thresholds were 0.56, 0.59, and 0.49 MPa for columellar, L-strut, and alar grafts, respectively. For comparison, human nasal septal cartilage is approximately 0.8 MPa. Conclusions There was little inter- and intra-rater variation of the identified threshold values for adequate graft stiffness. The identified threshold values will be useful for the design of tissue-engineered or semisynthetic cartilage grafts for use in structural nasal surgery. PMID:20513022

  11. Development of injectable hydrogels for nucleus pulposus replacement

    NASA Astrophysics Data System (ADS)

    Thomas, Jonathan D.

    Intervertebral disc degeneration has been reported as the underlying cause for 75% of cases of lower back pain and is marked by dehydration of the nucleus pulposus within the intervertebral disc. There have been many implant designs to replace the nucleus pulposus. Some researchers have proposed the replacement of the nucleus pulposus with hydrogel materials. The insertion of devices made from these materials further compromises the annulus of the disc. An ideal nucleus replacement could be injected into the disc space and form a solid in vivo. However, injectable replacements using curing elastomers and thermoplastic materials are not ideal because of the potentially harmful exothermic heat evolved from their reactions and the toxicity of the reactants used. We propose a hydrogel system that can be injected as a liquid at 25°C and solidified to yield a hydrogel within the intervertebral disc at 37°C. In aqueous solutions, these polymers have Lower Critical Solution Temperatures (LCST) between 25-37°C, making them unique candidate materials for this application. Poly(N-isopropylacrylamide) (PNIPAAm) is the most widely studied LCST polymer due to its drastic transition near body temperature. However, by itself, pure PNIPAAm forms a hydrogel that has low water content and can readily undergo plastic deformation. To increase the water content and impart elasticity to PNIPAAm hydrogels, grafted and branched hydrogel systems were created that incorporated the thermogelling PNIPAAm and hydrophilic poly(ethylene glycol) (PEG). In this research, the effects of polymer composition and monomer to initiator ratio, which controls polymer MW, on the in vitro swelling properties (mass, chemical, and compressive mechanical stability) of hydrogels formed from aqueous solutions of these polymers were evaluated. Immersion studies were also conducted in solutions to simulate the osmotic environment of the nucleus pulposus. The effects of repeated compression and unloading cycles

  12. Organosiloxane-grafted natural polymer coatings

    DOEpatents

    Sugama, Toshifumi

    1998-12-01

    A new family of polysaccharide graft polymers are provided as corrosion resistant coatings having antimicrobial properties which are useful on light metals such as aluminum, magnesium, zinc, steel and their alloys. Methods of making the polysaccharide graft polymers are also included. The methods of making the polysaccharide graft polymers involve reacting a polysaccharide source with an antimicrobial agent under conditions of hydrolysis-condensation. 17 figs.

  13. Vascularized nerve graft: a clinical contribution.

    PubMed

    Luchetti, R; De Santis, G; Soragni, O; Deluca, S; Pederzini, L; Alfarano, M; Landi, A

    1990-01-01

    The authors present 4 cases of vascularized nerve graft. The results were better than those obtained with traditional grafting. The indication is a rare one, and the experimental results are contradictory. Indications are limited to Volkmann ischemic syndromes, post-actinic lesions of the brachial plexus, infections and finally, post-burning scarring. Nevertheless, traditional nerve grafts remain the treatment of choice for peripheral nerve lesions which cannot undergo direct suturing.

  14. Novel expansion techniques for skin grafts

    PubMed Central

    Kadam, Dinesh

    2016-01-01

    The quest for skin expansion is not restricted to cover a large area alone, but to produce acceptable uniform surfaces, robust engraftment to withstand mechanical shear and infection, with a minimal donor morbidity. Ease of the technique, shorter healing period and reproducible results are essential parameters to adopt novel techniques. Significant advances seen in four fronts of autologous grafting are: (1) Dermal–epidermal graft expansion techniques, (2) epidermal graft harvests technique, (3) melanocyte-rich basal cell therapy for vitiligo and (4) robust and faster autologous cell cultures. Meek's original concept that the sum of perimeter of smaller grafts is larger than the harvested graft, and smaller the graft size, the greater is the potential for regeneration is witnessed in newer modification. Further, as graft size becomes smaller or minced, these micrografts can survive on the wound bed exudate irrespective of their dermal orientation. Expansion produced by 4 mm × 4 mm sized Meek micrografts is 10-folds, similarly 0.8 mm × 0.8 mm size micrografts produce 100-fold expansion, which becomes 700-fold with pixel grafts of 0.3 mm × 0.3 mm size. Fractional skin harvest is another new technique with 700 μ size full thickness graft. These provide instant autologous non-cultured graft to cover extensive areas with similar quality of engraftment surface as split skin grafts. Newer tools for epidermal blister graft harvest quickly, with uniform size to produce 7-fold expansions with reproducible results. In addition, donor area heals faster with minimal scar. Melanocyte-rich cell suspension is utilised in vitiligo surgery tapping the potential of hair root melanocytes. Further advances in the cell culture to reduce the cultivation time and provide stronger epidermal sheets with dermal carrier are seen in trials. PMID:27274117

  15. From AAA to Acuros XB-clinical implications of selecting either Acuros XB dose-to-water or dose-to-medium.

    PubMed

    Zifodya, Jackson M; Challens, Cameron H C; Hsieh, Wen-Long

    2016-06-01

    When implementing Acuros XB (AXB) as a substitute for anisotropic analytic algorithm (AAA) in the Eclipse Treatment Planning System, one is faced with a dilemma of reporting either dose to medium, AXB-Dm or dose to water, AXB-Dw. To assist with decision making on selecting either AXB-Dm or AXB-Dw for dose reporting, a retrospective study of treated patients for head & neck (H&N), prostate, breast and lung is presented. Ten patients, previously treated using AAA plans, were selected for each site and re-planned with AXB-Dm and AXB-Dw. Re-planning was done with fixed monitor units (MU) as well as non-fixed MUs. Dose volume histograms (DVH) of targets and organs at risk (OAR), were analyzed in conjunction with ICRU-83 recommended dose reporting metrics. Additionally, comparisons of plan homogeneity indices (HI) and MUs were done to further highlight the differences between the algorithms. Results showed that, on average AAA overestimated dose to the target volume and OARs by less than 2.0 %. Comparisons between AXB-Dw and AXB-Dm, for all sites, also showed overall dose differences to be small (<1.5 %). However, in non-water biological media, dose differences between AXB-Dw and AXB-Dm, as large as 4.6 % were observed. AXB-Dw also tended to have unexpectedly high 3D maximum dose values (>135 % of prescription dose) for target volumes with high density materials. Homogeneity indices showed that AAA planning and optimization templates would need to be adjusted only for the H&N and Lung sites. MU comparison showed insignificant differences between AXB-Dw relative to AAA and between AXB-Dw relative to AXB-Dm. However AXB-Dm MUs relative to AAA, showed an average difference of about 1.3 % signifying an underdosage by AAA. In conclusion, when dose is reported as AXB-Dw, the effect that high density structures in the PTV has on the dose distribution should be carefully considered. As the results show overall small dose differences between the algorithms, when

  16. SU-E-T-516: Dosimetric Validation of AcurosXB Algorithm in Comparison with AAA & CCC Algorithms for VMAT Technique.

    PubMed

    Kathirvel, M; Subramanian, V Sai; Arun, G; Thirumalaiswamy, S; Ramalingam, K; Kumar, S Ashok; Jagadeesh, K

    2012-06-01

    To dosimetrically validate AcurosXB algorithm for Volumetric Modulated Arc Therapy (VMAT) in comparison with standard clinical Anisotropic Analytic Algorithm(AAA) and Collapsed Cone Convolution(CCC) dose calculation algorithms. AcurosXB dose calculation algorithm is available with Varian Eclipse treatment planning system (V10). It uses grid-based Boltzmann equation solver to predict dose precisely in lesser time. This study was made to realize algorithms ability to predict dose accurately as its delivery for which five clinical cases each of Brain, Head&Neck, Thoracic, Pelvic and SBRT were taken. Verification plans were created on multicube phantom with iMatrixx-2D detector array and then dose prediction was done with AcurosXB, AAA & CCC (COMPASS System) algorithm and the same were delivered onto CLINAC-iX treatment machine. Delivered dose was captured in iMatrixx plane for all 25 plans. Measured dose was taken as reference to quantify the agreement between AcurosXB calculation algorithm against previously validated AAA and CCC algorithm. Gamma evaluation was performed with clinical criteria distance-to-agreement 3&2mm and dose difference 3&2% in omnipro-I'MRT software. Plans were evaluated in terms of correlation coefficient, quantitative area gamma and average gamma. Study shows good agreement between mean correlation 0.9979±0.0012, 0.9984±0.0009 & 0.9979±0.0011 for AAA, CCC & Acuros respectively. Mean area gamma for criteria 3mm/3% was found to be 98.80±1.04, 98.14±2.31, 98.08±2.01 and 2mm/2% was found to be 93.94±3.83, 87.17±10.54 & 92.36±5.46 for AAA, CCC & Acuros respectively. Mean average gamma for 3mm/3% was 0.26±0.07, 0.42±0.08, 0.28±0.09 and 2mm/2% was found to be 0.39±0.10, 0.64±0.11, 0.42±0.13 for AAA, CCC & Acuros respectively. This study demonstrated that the AcurosXB algorithm had a good agreement with the AAA & CCC in terms of dose prediction. In conclusion AcurosXB algorithm provides a valid, accurate and speedy alternative to AAA

  17. Plant grafting: insights into tissue regeneration.

    PubMed

    Melnyk, Charles W

    2017-02-01

    For millennia, people have cut and joined different plants together through a process known as grafting. The severed tissues adhere, the cells divide and the vasculature differentiates through a remarkable process of regeneration between two genetically distinct organisms as they become one. Grafting is becoming increasingly important in horticulture where it provides an efficient means for asexual propagation. Grafting also combines desirable roots and shoots to generate chimeras that are more vigorous, more pathogen resistant and more abiotic stress resistant. Thus, it presents an elegant and efficient way to improve plant productivity in vegetables and trees using traditional techniques. Despite this horticultural importance, we are only beginning to understand how plants regenerate tissues at the graft junction. By understanding grafting better, we can shed light on fundamental regeneration pathways and the basis for self/non-self recognition. We can also better understand why many plants efficiently graft whereas others cannot, with the goal of improving grafting so as to broaden the range of grafted plants to create even more desirable chimeras. Here, I review the latest findings describing how plants graft and provide insight into future directions in this emerging field.

  18. Towards Optogenetic Sensory Replacement

    PubMed Central

    Doroudchi, M. Mehdi; Greenberg, Kenneth P.; Zorzos, Anthony N.; Hauswirth, William W.; Fonstad, Clifton G.; Horsager, Alan; Boyden, Edward S.

    2013-01-01

    Over the last several years we have developed a rapidly-expanding suite of genetically-encoded reagents (e.g., ChR2, Halo, Arch, Mac, and others) that, when expressed in specific neuron types in the nervous system, enable their activities to be powerfully and precisely activated and silenced in response to light. If the genes that encode for these reagents can be delivered to cells in the body using gene therapy methods, and if the resultant protein payloads operate safely and effectively over therapeutically important periods of time, these molecules could subserve a set of precise prosthetics that use light as the trigger of information entry into the nervous system, e.g. for sensory replacement. Here we discuss the use of ChR2 to make the photoreceptor-deprived retina, as found in diseases such as retinitis pigmentosa, sensitive to light, enabling restoration of functional vision in a mouse model of blindness. We also discuss arrays of light sources that could be useful for delivering patterned sensory information into the nervous system. PMID:22255005

  19. [Transcatheter aortic valve replacement].

    PubMed

    Sawa, Yoshiki

    2014-07-01

    While transcatheter aortic valve replacement( TAVR) has spread rapidly all over the world for highrisk patients with severe aortic stenosis (AS), SAPIEN XT was approved in Japan in October 2013. Since that, approximately 400 TAVR cases were performed in Japan. In our institute, we have performed 164 cases since first case in Japan in 2009 and have achieved satisfactory early results(30-day mortality:1.2%). At the same time, however, simultaneously various TAVR-related complications including a paravalvular leak, stroke, vascular complications, and coronary obstruction were observed. A reduction in the incidence and severity of these complications had led technical improvements in various new devices(2nd generation TAVR device such as the SAPIEN 3, ACURATE, and JenaValve) and in implantation techniques including repositioning/recapturing features, paravalvular sealing technologies, and prevention of coronary obstruction. Furthermore, there is also increasing experience with special indications for TAVR such as pure aortic valve insufficiency or valve-in-valve techniques. Currently, an increasing number of publications of midterm results demonstrate good prosthetic valve function and durability, with good quality of life and low morbidity after TAVR. There are also some randomized trials such as PARTNER 2 or SURTAVI to investigate potential benefits of TAVR for intermediate-risk patients. These improvements in the TAVR devices promises the expansion of TAVR towards the treatment of lower-risk patients in the near future.

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

    PubMed

    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.

  1. Compliant electrospun silk fibroin tubes for small vessel bypass grafting.

    PubMed

    Marelli, Benedetto; Alessandrino, Antonio; Farè, Silvia; Freddi, Giuliano; Mantovani, Diego; Tanzi, Maria Cristina

    2010-10-01

    Processing silk fibroin (SF) by electrospinning offers a very attractive opportunity for producing three-dimensional nanofibrillar matrices in tubular form, which may be useful for a biomimetic approach to small calibre vessel regeneration. Bypass grafting of small calibre vessels, with a diameter less than 6mm, is performed mainly using autografts, like the saphenous vein or internal mammary artery. At present no polymeric grafts made of SF are commercially available, mainly due to inadequate properties (low compliance and lack of endothelium cells). The aim of this work was to electrospin SF into tubular structures (Ø=6mm) for small calibre vessel grafting, characterize the morphological, chemico-physical and mechanical properties of the electrospun SF structures and to validate their potential to interact with cells. The morphological properties of electrospun SF nanofibres were investigated by scanning electron microscopy. Chemico-physical analyses revealed an increase in the crystallinity of the structure of SF nanofibres on methanol treatment. Mechanical tests, i.e. compliance and burst pressure measurements, of the electrospun SF tubes showed that the inner pressure to radial deformation ratio was linear for elongation up to 15% and pressure up to 400 mm Hg. The mean compliance value between 80 and 120 mm Hg was higher than the values reported for both Goretex(R) and Dacron(R) grafts and for bovine heterografts, but still slightly lower than those of saphenous and umbilical vein, which nowadays represent the gold standard for the replacement of small calibre arteries. The electrospun tubes resisted up to 575+/-17 mmHg, which is more than four times the upper physiological pressure of 120 mmHg and more than twice the pathological upper pressures (range 180-220 mmHg). The in vitro tests showed a good cytocompatibility of the electrospun SF tubes. Therefore, the electrospun SF tubes developed within this work represent a suitable candidate for small calibre

  2. Grafted methylenediphosphonate ion exchange resins

    DOEpatents

    Trochimcznk, Andrzej W.; Gatrone, Ralph C.; Alexandratos, Spiro; Horwitz, E. Philip

    1998-01-27

    An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorous. The pendent groups have the formula ##STR1## wherein R is hydrogen, a cation or mixtures thereof; and R.sup.1 is hydrogen or an C.sub.1 -C.sub.2 alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange-resin are also disclosed.

  3. Grafted methylenediphosphonate ion exchange resins

    DOEpatents

    Trochimcznk, A.W.; Gatrone, R.C.; Alexandratos, S.; Horwitz, E.P.

    1997-04-08

    An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorus. The pendent groups have the formula as shown in the patent wherein R is hydrogen, a cation or mixtures thereof; and R{sup 1} is hydrogen or an C{sub 1}-C{sub 2} alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange resin are also disclosed.

  4. Grafted methylenediphosphonate ion exchange resins

    DOEpatents

    Trochimcznk, Andrzej W.; Gatrone, Ralph C.; Alexandratos, Spiro; Horwitz, E. Philip

    1997-01-01

    An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorous. The pendent groups have the formula ##STR1## wherein R is hydrogen, a cation or mixtures thereof; and R.sup.1 is hydrogen or an C.sub.1 -C.sub.2 alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange resin are also disclosed.

  5. Antenna Controller Replacement Software

    NASA Technical Reports Server (NTRS)

    Chao, Roger Y.; Morgan, Scott C.; Strain, Martha M.; Rockwell, Stephen T.; Shimizu, Kenneth J.; Tehrani, Barzia J.; Kwok, Jaclyn H.; Tuazon-Wong, Michelle; Valtier, Henry; Nalbandi, Reza; hide

    2010-01-01

    The Antenna Controller Replacement (ACR) software accurately points and monitors the Deep Space Network (DSN) 70-m and 34-m high-efficiency (HEF) ground-based antennas that are used to track primarily spacecraft and, periodically, celestial targets. To track a spacecraft, or other targets, the antenna must be accurately pointed at the spacecraft, which can be very far away with very weak signals. ACR s conical scanning capability collects the signal in a circular pattern around the target, calculates the location of the strongest signal, and adjusts the antenna pointing to point directly at the spacecraft. A real-time, closed-loop servo control algorithm performed every 0.02 second allows accurate positioning of the antenna in order to track these distant spacecraft. Additionally, this advanced servo control algorithm provides better antenna pointing performance in windy conditions. The ACR software provides high-level commands that provide a very easy user interface for the DSN operator. The operator only needs to enter two commands to start the antenna and subreflector, and Master Equatorial tracking. The most accurate antenna pointing is accomplished by aligning the antenna to the Master Equatorial, which because of its small size and sheltered location, has the most stable pointing. The antenna has hundreds of digital and analog monitor points. The ACR software provides compact displays to summarize the status of the antenna, subreflector, and the Master Equatorial. The ACR software has two major functions. First, it performs all of the steps required to accurately point the antenna (and subreflector and Master Equatorial) at the spacecraft (or celestial target). This involves controlling the antenna/ subreflector/Master-Equatorial hardware, initiating and monitoring the correct sequence of operations, calculating the position of the spacecraft relative to the antenna, executing the real-time servo control algorithm to maintain the correct position, and

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

    PubMed

    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

  7. Design and development of multilayer vascular graft

    NASA Astrophysics Data System (ADS)

    Madhavan, Krishna

    2011-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2007-06-01

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

  9. Postural stabilizing effect of alfacalcidol and active absorbable algal calcium (AAA Ca) compared with calcium carbonate assessed by computerized posturography.

    PubMed

    Fujita, Takuo; Nakamura, Shoji; Ohue, Mutsumi; Fujii, Yoshio; Miyauchi, Akimitsu; Takagi, Yasuyuki; Tsugeno, Hirofumi

    2007-01-01

    Sway and postural instability have drawn attention as a risk factor for osteoporotic fracture, in addition to low bone mineral density (BMD) and poor bone quality. In view of the fracture-reducing effect of alfacalcidol and active absorbable algal calcium (AAA Ca) not readily explained by rather mild increases of BMD, attempts were made to evaluate postural stabilizing effect of alfacalcidol, AAA Ca, and calcium carbonate (CaCO(3)) by computerized posturography. Track of the gravity center was analyzed to calculate parameters related to tract length, track range, and track density to express the degree of sway before and after supplementation in 126 subjects ranging in age between 20 and 81 years randomly divided into four groups. Supplementation with AAA Ca containing 900 mg elemental Ca (group A), no calcium (group B), CaCO(3) also containing 900 mg elemental Ca (group C), or alfacalcidol (group D) continued daily for 12 months. For each parameter, the ratio closed eye value/open eye value (Romberg ratio) was calculated to detect aggravation of sway by eye closure. Age, parameters of Ca and P, and proportions of subjects with fracture and those with low BMD showed no marked deviation among the groups. With eyes open, significant decreases of a track range parameter (REC) from group B was noted in groups A (P = 0.0397) and D (P = 0.0296), but not in group C according to multiple comparison by Scheffe, indicating superior postural stabilizing effect of A and D over C. In the first 2 months, a significant fall was already evident in REC from group B in group D (P = 0.0120) with eyes open. Paired comparison of sway parameters before and after supplementation revealed a significant increase of track density parameter (LNGA), indicating sway control efficiency and a significant decrease of REC in groups A and D compared to group B with eyes open. With eyes closed, only group A showed a significant improvement from group B (P = 0.0456; Fig. 1), with a significant

  10. Electrostrictive Graft Elastomers and Applications

    NASA Technical Reports Server (NTRS)

    Su, J.; Harrison, J. S.; St.Clair, T. L.; Bar-Cohen, Y.; Leary, S.

    1999-01-01

    Efficient actuators that are lightweight, high performance and compact are needed to support telerobotic requirements for future NASA missions. In this work, we present a new class of electromechanically active polymers that can potentially be used as actuators to meet many NASA needs. The materials are graft elastomers that offer high strain under an applied electric field. Due to its higher mechanical modulus, this elastomer also has a higher strain energy density as compared to previously reported electrostrictive polyurethane elastomers. The dielectric, mechanical and electromechanical properties of this new electrostrictive elastomer have been studied as a function of temperature and frequency. Combined with structural analysis using x-ray diffraction and differential scanning calorimetry on the new elastomer, structure-property interrelationship and mechanisms of the electric field induced strain in the graft elastomer have also been investigated. This electroactive polymer (EAP) has demonstrated high actuation strain and high mechanical energy density. The combination of these properties with its tailorable molecular composition and excellent processability makes it attractive for a variety of actuation tasks. The experimental results and applications will be presented.

  11. Educating My Replacement

    NASA Astrophysics Data System (ADS)

    Tarter, Jill

    , in partnership with the dedicated teachers out there, I think I can help promote the critical thinking skills and scientific literacy of the next generation of voters. Hopefully, I can also help train my replacement to be a better scientist, capable of seizing all the opportunities generated by advances in technology and our improved understanding of the universe to craft search strategies with greater probability of success than those I have initiated.

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

    PubMed

    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.

  13. Xenon treatment protects against cold ischemia associated delayed graft function and prolongs graft survival in rats.

    PubMed

    Zhao, H; Watts, H R; Chong, M; Huang, H; Tralau-Stewart, C; Maxwell, P H; Maze, M; George, A J T; Ma, D

    2013-08-01

    Prolonged hypothermic storage causes ischemia-reperfusion injury (IRI) in the renal graft, which is considered to contribute to the occurrence of the delayed graft function (DGF) and chronic graft failure. Strategies are required to protect the graft and to prolong renal graft survival. We demonstrated that xenon exposure to human proximal tubular cells (HK-2) led to activation of range of protective proteins. Xenon treatment prior to or after hypothermia-hypoxia challenge stabilized the HK-2 cellular structure, diminished cytoplasmic translocation of high-mobility group box (HMGB) 1 and suppressed NF-κB activation. In the syngeneic Lewis-to-Lewis rat model of kidney transplantation, xenon exposure to donors before graft retrieval or to recipients after engraftment decreased caspase-3 expression, localized HMGB-1 within nuclei and prevented TLR-4/NF-κB activation in tubular cells; serum pro-inflammatory cytokines IL-1β, IL-6 and TNF-α were reduced and renal function was preserved. Xenon treatment of graft donors or of recipients prolonged renal graft survival following IRI in both Lewis-to-Lewis isografts and Fischer-to-Lewis allografts. Xenon induced cell survival or graft functional recovery was abolished by HIF-1α siRNA. Our data suggest that xenon treatment attenuates DGF and enhances graft survival. This approach could be translated into clinical practice leading to a considerable improvement in long-term graft survival. © Copyright 2013 The American Society of Transplantation and the American Society of Transplant Surgeons.

  14. Xenon Treatment Protects Against Cold Ischemia Associated Delayed Graft Function and Prolongs Graft Survival in Rats

    PubMed Central

    Zhao, H; Watts, H R; Chong, M; Huang, H; Tralau-Stewart, C; Maxwell, P H; Maze, M; George, A J T; Ma, D

    2013-01-01

    Prolonged hypothermic storage causes ischemia-reperfusion injury (IRI) in the renal graft, which is considered to contribute to the occurrence of the delayed graft function (DGF) and chronic graft failure. Strategies are required to protect the graft and to prolong renal graft survival. We demonstrated that xenon exposure to human proximal tubular cells (HK-2) led to activation of range of protective proteins. Xenon treatment prior to or after hypothermia–hypoxia challenge stabilized the HK-2 cellular structure, diminished cytoplasmic translocation of high-mobility group box (HMGB) 1 and suppressed NF-κB activation. In the syngeneic Lewis-to-Lewis rat model of kidney transplantation, xenon exposure to donors before graft retrieval or to recipients after engraftment decreased caspase-3 expression, localized HMGB-1 within nuclei and prevented TLR-4/NF-κB activation in tubular cells; serum pro-inflammatory cytokines IL-1β, IL-6 and TNF-α were reduced and renal function was preserved. Xenon treatment of graft donors or of recipients prolonged renal graft survival following IRI in both Lewis-to-Lewis isografts and Fischer-to-Lewis allografts. Xenon induced cell survival or graft functional recovery was abolished by HIF-1α siRNA. Our data suggest that xenon treatment attenuates DGF and enhances graft survival. This approach could be translated into clinical practice leading to a considerable improvement in long-term graft survival. PMID:23710625

  15. Ethylene vinyl acetate based radiation grafted hydrophilic matrices: Process parameter standardization, grafting kinetics and characterization

    NASA Astrophysics Data System (ADS)

    Chaudhari, C. V.; Mondal, R. K.; Dubey, K. A.; Grover, V.; Panicker, L.; Bhardwaj, Y. K.; Varshney, L.

    2016-08-01

    A transparent, elastomeric, grafted matrix for several potential applications was synthesized by single-step simultaneous radiation grafting of methacrylic acid onto ethylene vinyl acetate (EVA). CuSO4 was found to be the most suitable homo-polymerization inhibitor among different inhibitors tried. The grafting kinetics was found to be a strong function of dose rate (D) and monomer content (M) and an equation relating grafting rate Rg=Kg [M]1.13D0.23 was deduced. Crystallinity of the grafted matrices as assessed from XRD and DSC measurements indicated decrease in crystalline content with increase in grafting yield, suggesting crystalline domain of EVA get disrupted on grafting. Elastic modulus increased linearly with the increase in grafting yield, though elongation at break decreased precipitously from 900% to 30% at even 9% grafting. Thermo-gravimetric analysis showed three step weight loss of the grafted EVA matrix. The grafting of MAA resulted in increase in surface energy mainly due to enhanced polar component.

  16. Radiation graft modification of EPDM rubber

    NASA Astrophysics Data System (ADS)

    Katbab, A. A.; Burford, R. P.; Garnett, J. L.

    N-Vinyl pyrrolidone (NVP), 2-hydroxyethylmethacrylate (HEMA) and acrylamide (AAm) have been grafted to the surface of rubber vulcanizates based on ethylene-propylene-terpolymer (EPDM) using the simultaneous radiation method to alter surface properties such as wettability and therefore biocompatibility. The effect of monomer concentration, solvent and EPDM structural factors on the grafting behavior have been investigated. The inhibitory effect upon homopolymerization of various salts has also been evaluated for the three monomers. NVP and HEMA could be grafted onto EPDM rubber in the presence of aqueous solutions of cupric nitrate at 0.005 M and 1.0 M concentrations respectively. Aqueous solutions of Mohr's salt (ammonium ferrous sulphate) at 0.05 M not only suppressed the homopolymerization of AAm but also increased grafting yield. The percentage grafting also increased with increasing AAm concentration. A mechanism has been proposed to explain the behaviour of these monomers. The inclusion of multifunctional acrylates in additive amounts (1.0 vol%) enhanced the graft degree. Modified samples were able to be efficiently stained, allowing the depth of the graft copolymerization to be determined by light microscopy. Water was found to have an accelerating effect on the polymerization of these monomers, but methanol prevented their polymerization completely. The effect of EPDM structural factors upon degree of grafting was found to vary, depending upon the monomer type.

  17. Emerging concepts in liver graft preservation

    PubMed Central

    Bejaoui, Mohamed; Pantazi, Eirini; Folch-Puy, Emma; Baptista, Pedro M; García-Gil, Agustín; Adam, René; Roselló-Catafau, Joan

    2015-01-01

    The urgent need to expand the donor pool in order to attend to the growing demand for liver transplantation has obliged physicians to consider the use of suboptimal liver grafts and also to redefine the preservation strategies. This review examines the different methods of liver graft preservation, focusing on the latest advances in both static cold storage and machine perfusion (MP). The new strategies for static cold storage are mainly designed to increase the fatty liver graft preservation via the supplementation of commercial organ preservation solutions with additives. In this paper we stress the importance of carrying out effective graft washout after static cold preservation, and present a detailed discussion of the future perspectives for dynamic graft preservation using MP at different temperatures (hypothermia at 4 °C, normothermia at 37 °C and subnormothermia at 20 °C-25 °C). Finally, we highlight some emerging applications of regenerative medicine in liver graft preservation. In conclusion, this review discusses the “state of the art” and future perspectives in static and dynamic liver graft preservation in order to improve graft viability. PMID:25593455

  18. Physicochemical characterization of porcine bone-derived grafting material and comparison with bovine xenografts for dental applications.

    PubMed

    Lee, Jung Heon; Yi, Gyu Sung; Lee, Jin Woong; Kim, Deug Joong

    2017-12-01

    The physicochemical properties of a xenograft are very important because they strongly influence the bone regeneration capabilities of the graft material. Even though porcine xenografts have many advantages, only a few porcine xenografts are commercially available, and most of their physicochemical characteristics have yet to be reported. Thus, in this work we aimed to investigate the physicochemical characteristics of a porcine bone grafting material and compare them with those of 2 commercially available bovine xenografts to assess the potential of xenogenic porcine bone graft materials for dental applications. We used various characterization techniques, such as scanning electron microscopy, the Brunauer-Emmett-Teller adsorption method, atomic force microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and others, to compare the physicochemical properties of xenografts of different origins. The porcine bone grafting material had relatively high porosity (78.4%) and a large average specific surface area (SSA; 69.9 m 2 /g), with high surface roughness (10-point average roughness, 4.47 µm) and sub-100-nm hydroxyapatite crystals on the surface. Moreover, this material presented a significant fraction of sub-100-nm pores, with negligible amounts of residual organic substances. Apart from some minor differences, the overall characteristics of the porcine bone grafting material were very similar to those of one of the bovine bone grafting material. However, many of these morphostructural properties were significantly different from the other bovine bone grafting material, which exhibited relatively smooth surface morphology with a porosity of 62.0% and an average SSA of 0.5 m 2 /g. Considering that both bovine bone grafting materials have been successfully used in oral surgery applications in the last few decades, this work shows that the porcine-derived grafting material possesses most of the key physiochemical characteristics required for its

  19. Polyethylene oxide hydration in grafted layers

    NASA Astrophysics Data System (ADS)

    Dormidontova, Elena; Wang, Zilu

    Hydration of water soluble polymers is one of the key-factors defining their conformation and properties, similar to biopolymers. Polyethylene oxide (PEO) is one of the most important biomedical-applications polymers and is known for its reverse temperature solubility due to hydrogen bonding with water. As in many practical applications PEO chains are grafted to surfaces, e.g. of nanoparticles or planar surfaces, it is important to understand PEO hydration in such grafted layers. Using atomistic molecular dynamic simulations we investigate the details of molecular conformation and hydration of PEO end-grafted to gold surfaces. We analyze polymer and water density distribution as a function of distance from the surface for different grafting densities. Based on a detailed analysis of hydrogen bonding between polymer and water in grafted PEO layers, we will discuss the extent of PEO hydration and its implication for polymer conformation, mobility and layer properties. This research is supported by NSF (DMR-1410928).

  20. Cranial Bone Graft Donor Site Reconstruction.

    PubMed

    Çelik, Muzaffer

    2017-01-01

    My most important concern, in my entire experience with cranial bone grafting procedures, is managing the bone graft donor site such as donor site cavity from harvesting and weakness of the cranium. The most common patient complaint, following cranial bone grafting for aesthetic indications, is the presence of a cavity at the donor site. The authors have managed more than 200 patients since 2001, wherein the cranial bone graft-donor sites were reconstructed with tiny bone chip lamellae harvested from the area adjacent to the donor site. This procedure was associated with a low incidence of patient complaints, thereby suggesting higher patient satisfaction. This approach for cranial bone grafting appears to have a high patient acceptance.

  1. Comparison of Acuros (AXB) and Anisotropic Analytical Algorithm (AAA) for dose calculation in treatment of oesophageal cancer: effects on modelling tumour control probability.

    PubMed

    Padmanaban, Sriram; Warren, Samantha; Walsh, Anthony; Partridge, Mike; Hawkins, Maria A

    2014-12-23

    To investigate systematic changes in dose arising when treatment plans optimised using the Anisotropic Analytical Algorithm (AAA) are recalculated using Acuros XB (AXB) in patients treated with definitive chemoradiotherapy (dCRT) for locally advanced oesophageal cancers. We have compared treatment plans created using AAA with those recalculated using AXB. Although the Anisotropic Analytical Algorithm (AAA) is currently more widely used in clinical routine, Acuros XB (AXB) has been shown to more accurately calculate the dose distribution, particularly in heterogeneous regions. Studies to predict clinical outcome should be based on modelling the dose delivered to the patient as accurately as possible. CT datasets from ten patients were selected for this retrospective study. VMAT (Volumetric modulated arc therapy) plans with 2 arcs, collimator rotation ± 5-10° and dose prescription 50 Gy / 25 fractions were created using Varian Eclipse (v10.0). The initial dose calculation was performed with AAA, and AXB plans were created by re-calculating the dose distribution using the same number of monitor units (MU) and multileaf collimator (MLC) files as the original plan. The difference in calculated dose to organs at risk (OAR) was compared using dose-volume histogram (DVH) statistics and p values were calculated using the Wilcoxon signed rank test. The potential clinical effect of dosimetric differences in the gross tumour volume (GTV) was evaluated using three different TCP models from the literature. PTV Median dose was apparently 0.9 Gy lower (range: 0.5 Gy - 1.3 Gy; p < 0.05) for VMAT AAA plans re-calculated with AXB and GTV mean dose was reduced by on average 1.0 Gy (0.3 Gy -1.5 Gy; p < 0.05). An apparent difference in TCP of between 1.2% and 3.1% was found depending on the choice of TCP model. OAR mean dose was lower in the AXB recalculated plan than the AAA plan (on average, dose reduction: lung 1.7%, heart 2.4%). Similar trends were seen for CRT plans

  2. Prime Contract Awards Over $25,000 by Major System, Contractor and State Part 1 (AAA-NAVY-AVG NAVY)

    DTIC Science & Technology

    1990-01-01

    Q-COC’) -4 M’i (a -4 c"a(aeo - ( D 0 AC 1 -ao f-.r qva 0(%Ioa.4 ()t a. c~cv(vc4 z *Za in -0f (4Jl w -44- m - .41 C,4 Ui 0 C4 IC4 P- -a l~~II I II cLE E...AO-A236 155iiiilulll l I l 1990 ANNUAL Prime Contract Awards Over $25,000 by Major System, Contractor and State Part 1 (AAA-NAVY-AVG NAVY) WHS...Special . 1 -9 __28284 pages I1 ~ . - e21 M(%I% cm -40W -4 I4 m V .. 4 mt WC)a r a- 4-r w~l w zl- qt qt V .4- 01-4 41-4 . 40 o r Lu V) c I OL 9 C U c

  3. Interaction studies of resistomycin from Streptomyces aurantiacus AAA5 with calf thymus DNA and bovine serum albumin

    NASA Astrophysics Data System (ADS)

    Vijayabharathi, R.; Sathyadevi, P.; Krishnamoorthy, P.; Senthilraja, D.; Brunthadevi, P.; Sathyabama, S.; Priyadarisini, V. Brindha

    2012-04-01

    Resistomycin, a secondary metabolite produced by Streptomyces aurantiacus AAA5. The binding interaction of resistomycin with calf thymus DNA (CT DNA) and bovine serum albumin (BSA) was investigated by spectrophotometry, spectrofluorimetry, circular dichroism (CD) and synchronous fluorescence techniques under physiological conditions in vitro. Absorption spectral studies along with the fluorescence competition with ethidium bromide measurements and circular dichroism clearly suggest that the resistomycin bind with CT DNA relatively strong via groove binding. BSA interaction results revealed that the drug was found to quench the fluorescence intensity of the protein through a static quenching mechanism. The number of binding sites 'n' and apparent binding constant 'K' calculated according to the Scatchard equation exhibit a good binding property to bovine serum albumin protein. In addition, the results observed from synchronous fluorescence measurements clearly demonstrate the occurrence of conformational changes of BSA upon addition of the test compound.

  4. High-intensity interval exercise training before abdominal aortic aneurysm repair (HIT-AAA): protocol for a randomised controlled feasibility trial.

    PubMed

    Tew, Garry A; Weston, Matthew; Kothmann, Elke; Batterham, Alan M; Gray, Joanne; Kerr, Karen; Martin, Denis; Nawaz, Shah; Yates, David; Danjoux, Gerard

    2014-01-10

    In patients with large abdominal aortic aneurysm (AAA), open surgical or endovascular aneurysm repair procedures are often used to minimise the risk of aneurysm-related rupture and death; however, aneurysm repair itself carries a high risk. Low cardiopulmonary fitness is associated with an increased risk of early post-operative complications and death following elective AAA repair. Therefore, fitness should be enhanced before aneurysm repair. High-intensity interval exercise training (HIT) is a potent, time-efficient strategy for enhancing cardiopulmonary fitness. Here, we describe a feasibility study for a definitive trial of a pre-operative HIT intervention to improve post-operative outcomes in patients undergoing elective AAA repair. A minimum of 50 patients awaiting elective repair of a 5.5-7.0 cm infrarenal AAA will be allocated by minimisation to HIT or usual care control in a 1:1 ratio. The patients allocated to HIT will complete three hospital-based exercise sessions per week, for 4 weeks. Each session will include 2 or 4 min of high-intensity stationary cycling followed by the same duration of easy cycling or passive recovery, repeated until a total of 16 min of high-intensity exercise is accumulated. Outcomes to be assessed before randomisation and 24-48 h before aneurysm repair include cardiopulmonary fitness, maximum AAA diameter and health-related quality of life. In the post-operative period, we will record destination (ward or critical care unit), organ-specific morbidity, mortality and the durations of critical care and hospital stay. Twelve weeks after the discharge, participants will be interviewed to reassess quality of life and determine post-discharge healthcare utilisation. The costs associated with the exercise intervention and healthcare utilisation will be calculated. Ethics approval was secured through Sunderland Research Ethics Committee. The findings of the trial will be disseminated through peer-reviewed journals, and national and

  5. In vitro propagation and assessment of the genetic fidelity of Musa acuminata (AAA) cv. Vaibalhla derived from immature male flowers.

    PubMed

    Hrahsel, Lalremsiami; Basu, Adreeja; Sahoo, Lingaraj; Thangjam, Robert

    2014-02-01

    An efficient in vitro propagation method has been developed for the first time for Musa acuminata (AAA) cv. Vaibalhla, an economically important banana cultivar of Mizoram, India. Immature male flowers were used as explants. Murashige and Skoog's (MS) medium supplemented with plant growth regulators (PGRs) were used for the regeneration process. Out of different PGR combinations, MS medium supplemented with 2 mg L(-1) 6-benzylaminopurine (BAP) + 0.5 mg L(-1) α-naphthalene acetic acid (NAA) was optimal for production of white bud-like structures (WBLS). On this medium, explants produced the highest number of buds per explant (4.30). The highest percentage (77.77) and number (3.51) of shoot formation from each explants was observed in MS medium supplemented with 2 mg L(-1) kinetin + 0.5 mg L(-1) NAA. While MS medium supplemented with a combination of 2 mg L(-1) BAP + 0.5 mg L(-1) NAA showed the maximum shoot length (14.44 cm). Rooting efficiency of the shoots was highest in the MS basal medium without any PGRs. The plantlets were hardened successfully in the greenhouse with 96% survival rate. Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers were employed to assess the genetic stability of in vitro regenerated plantlets of M. acuminata (AAA) cv. Vaibalhla. Eight RAPD and 8 ISSR primers were successfully used for the analysis from the 40 RAPD and 30 ISSR primers screened initially. The amplified products were monomorphic across all the regenerated plants and were similar to the mother plant. The present standardised protocol will find application in mass production, conservation and genetic transformation studies of this commercially important banana.

  6. Structural Characterization of a Newly Identified Component of α-Carboxysomes: The AAA+ Domain Protein CsoCbbQ

    DOE PAGES

    Sutter, Markus; Roberts, Evan W.; Gonzalez, Raul C.; ...

    2015-11-05

    Carboxysomes are bacterial microcompartments that enhance carbon fixation by concentrating ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and its substrate CO 2 within a proteinaceous shell. They are found in all cyanobacteria, some purple photoautotrophs and many chemoautotrophic bacteria. Carboxysomes consist of a protein shell that encapsulates several hundred molecules of RuBisCO, and contain carbonic anhydrase and other accessory proteins. Genes coding for carboxysome shell components and the encapsulated proteins are typically found together in an operon. The α-carboxysome operon is embedded in a cluster of additional, conserved genes that are presumably related to its function. In many chemoautotrophs, products of the expanded carboxysomemore » locus include CbbO and CbbQ, a member of the AAA+ domain superfamily. We bioinformatically identified subtypes of CbbQ proteins and show that their genes frequently co-occur with both Form IA and Form II RuBisCO. The α-carboxysome-associated ortholog, CsoCbbQ, from Halothiobacillus neapolitanus forms a hexamer in solution and hydrolyzes ATP. The crystal structure shows that CsoCbbQ is a hexamer of the typical AAA+ domain; the additional C-terminal domain, diagnostic of the CbbQ subfamily, structurally fills the inter-monomer gaps, resulting in a distinctly hexagonal shape. Finally, we show that CsoCbbQ interacts with CsoCbbO and is a component of the carboxysome shell, the first example of ATPase activity associated with a bacterial microcompartment.« less

  7. Electrospun Scaffolds for Tissue Engineering of Vascular Grafts

    PubMed Central

    Hasan, Anwarul; Memic, Adnan; Annabi, Nasim; Hossain, Monowar; Paul, Arghya; Dokmeci, Mehmet R.; Dehghani, Fariba; Khademhosseini, Ali

    2013-01-01

    There is a growing demand for off-the-shelf tissue engineered vascular grafts (TEVGs) for replacement or bypass of damaged arteries in various cardiovascular diseases. Scaffolds from the decellularized tissue skeletons to biopolymers and biodegradable synthetic polymers have been used for fabricating TEVGs. However, several issues have not yet been resolved, which include the inability to mimic the mechanical properties of native tissues, and the ability for long term patency and growth required for in vivo function. Electrospinning is a popular technique for the production of scaffolds that has the potential to address these issues. However, its application to human TEVGs has not yet been achieved. This review provides an overview of tubular scaffolds that have been prepared by electrospinning with potential for TEVG applications. PMID:23973391

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

    PubMed

    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.

  9. Early matrix change of a nanostructured bone grafting substitute in the rat.

    PubMed

    Xu, Weiguo; Holzhüter, Gerd; Sorg, Heiko; Wolter, Daniel; Lenz, Solvig; Gerber, Thomas; Vollmar, Brigitte

    2009-11-01

    A nanocrystalline bone substitute embedded in a highly porous silica gel matrix (NanoBone) has previously been shown to bridge bone defects by an organic matrix. As the initial host response on the bone graft substitute might be a determinant for subsequent bone formation, our present purpose was to characterize the early tissue reaction on this biomaterial. After implantation of 80 mg of NanoBone into the adipose neck tissue of a total of 35 rats, grafts were harvested for subsequent analysis at days 3, 6, 9, 12, and 21. The biomaterial was found encapsulated by granulation tissue which partly penetrated the implant at day 3 and completely pervaded the graft at day 12 on implantation. Histology revealed tartrate-resistant acid phosphatase (TRAP)-positive giant cells covering the biomaterial. ED1 (CD68) immunopositivity of these cells further indicated their osteoclast-like phenotype. Scanning electron microscopy revealed organic tissue components within the periphery of the graft already at day 9, whereas the central hematoma region still presented the silica-surface of the biomaterial. Energy dispersive X-ray spectroscopy further demonstrated that the silica gel was degraded faster in the peripheral granulation tissue than in the central hematoma and was replaced by organic host components by day 12. In conclusion, the silica gel matrix is rapidly replaced by carbohydrate macromolecules. This might represent a key step in the process of graft degradation on its way toward induction of bone formation. The unique composition and structure of this nanoscaled biomaterial seem to support its degradation by host osteoclast-like giant cells.

  10. Percutaneous coronary intervention strategies and prognosis for graft lesions following coronary artery bypass grafting

    PubMed Central

    LIU, YIN; ZHOU, XIUJUN; JIANG, HUA; GAO, MINGDONG; WANG, LIN; SHI, YUTIAN; GAO, JING

    2015-01-01

    The purpose of this study was to compare the prognosis of graft-percutaneous coronary intervention (PCI) and native vessel (NV)-PCI, drug-eluting stents (DESs) and bare-metal stents (BMSs) for the treatment of graft lesions following coronary artery bypass grafting (CABG), and to determine the risk factors for major adverse cardiac events (MACEs). A total of 289 patients who underwent PCI following CABG between August 2005 and March 2010 were retrospectively analyzed. The effects on survival were compared among patients who underwent NV- and graft-PCI, and DES and BMS implantation. Additionally, the risk factors for MACEs following PCI for graft lesions were analyzed. The findings showed that MACE-free and revascularization-free survival rates were significantly higher in the NV-PCI group compared with those in the graft-PCI group. There were 63 cases (29.0%) of MACEs in the DES group and 25 cases (52.1%) in the BMS group. In patients undergoing NV-PCI, the DES group had significantly fewer MACEs and less target vessel revascularization (TVR) than the BMS group. In patients undergoing graft-PCI, the DES group showed a tendency for fewer MACEs and a lower incidence of cardiac mortality, myocardial infarction and TVR compared with the BMS group. Diabetes, an age of >70 years and graft-PCI were independent risk factors for MACEs in patients post-PCI. It is concluded that NV-PCI has superior long-term outcomes compared with graft-PCI, and should therefore be considered as the first-line treatment for graft disease following CABG. Despite this, graft-PCI remains a viable option. DESs are the first choice for graft-PCI due to their safety and efficacy and their association with reduced mortality and MACE rate. Diabetes, older age and graft-PCI are independent risk factors for MACEs in patients post-CABG who are undergoing revascularization. PMID:26136874

  11. Autologous patch graft in tube shunt surgery.

    PubMed

    Aslanides, I M; Spaeth, G L; Schmidt, C M; Lanzl, I M; Gandham, S B

    1999-10-01

    To evaluate an alternate method of covering the subconjunctival portion of the tube in aqueous shunt surgery. Evidence of tube erosion, graft-related infection, graft melting, or other associated intraocular complications were evaluated. A retrospective study of 16 patients (17 eyes) who underwent tube shunt surgery at Wills Eye Hospital between July 1991 and October 1996 was conducted. An autologous either "free" or "rotating" scleral lamellar graft was created to cover the subconjunctival portion of the tube shunt. All patients were evaluated for at least 6 months, with a mean follow-up of 14.8 months (range 6-62 months). All eyes tolerated the autologous graft well, with no clinical evidence of tube erosion, or graft-related or intraocular complications. Autologous patch graft in tube shunt surgery appears--in selected cases--to be an effective, safe and inexpensive surgical alternative to allogenic graft materials. It also offers ease of availability, and eliminates the risk of transmitting infectious disease.

  12. 3D Printed Abdominal Aortic Aneurysm Phantom for Image Guided Surgical Planning with a Patient Specific Fenestrated Endovascular Graft System

    PubMed Central

    Meess, Karen M.; Izzo, Richard L.; Dryjski, Maciej L.; Curl, Richard E.; Harris, Linda M.; Springer, Michael; Siddiqui, Adnan H.; Rudin, Stephen; Ionita, Ciprian N.

    2017-01-01

    Following new trends in precision medicine, Juxatarenal Abdominal Aortic Aneurysm (JAAA) treatment has been enabled by using patient-specific fenestrated endovascular grafts. The X-ray guided procedure requires precise orientation of multiple modular endografts within the arteries confirmed via radiopaque markers. Patient-specific 3D printed phantoms could familiarize physicians with complex procedures and new devices in a risk-free simulation environment to avoid periprocedural complications and improve training. Using the Vascular Modeling Toolkit (VMTK), 3D Data from a CTA imaging of a patient scheduled for Fenestrated EndoVascular Aortic Repair (FEVAR) was segmented to isolate the aortic lumen, thrombus, and calcifications. A stereolithographic mesh (STL) was generated and then modified in Autodesk MeshMixer for fabrication via a Stratasys Eden 260 printer in a flexible photopolymer to simulate arterial compliance. Fluoroscopic guided simulation of the patient-specific FEVAR procedure was performed by interventionists using all demonstration endografts and accessory devices. Analysis compared treatment strategy between the planned procedure, the simulation procedure, and the patient procedure using a derived scoring scheme. Results With training on the patient-specific 3D printed AAA phantom, the clinical team optimized their procedural strategy. Anatomical landmarks and all devices were visible under x-ray during the simulation mimicking the clinical environment. The actual patient procedure went without complications. Conclusions With advances in 3D printing, fabrication of patient specific AAA phantoms is possible. Simulation with 3D printed phantoms shows potential to inform clinical interventional procedures in addition to CTA diagnostic imaging. PMID:28638171

  13. 3D printed abdominal aortic aneurysm phantom for image guided surgical planning with a patient specific fenestrated endovascular graft system

    NASA Astrophysics Data System (ADS)

    Meess, Karen M.; Izzo, Richard L.; Dryjski, Maciej L.; Curl, Richard E.; Harris, Linda M.; Springer, Michael; Siddiqui, Adnan H.; Rudin, Stephen; Ionita, Ciprian N.

    2017-03-01

    Following new trends in precision medicine, Juxatarenal Abdominal Aortic Aneurysm (JAAA) treatment has been enabled by using patient-specific fenestrated endovascular grafts. The X-ray guided procedure requires precise orientation of multiple modular endografts within the arteries confirmed via radiopaque markers. Patient-specific 3D printed phantoms could familiarize physicians with complex procedures and new devices in a risk-free simulation environment to avoid periprocedural complications and improve training. Using the Vascular Modeling Toolkit (VMTK), 3D Data from a CTA imaging of a patient scheduled for Fenestrated EndoVascular Aortic Repair (FEVAR) was segmented to isolate the aortic lumen, thrombus, and calcifications. A stereolithographic mesh (STL) was generated and then modified in Autodesk MeshMixer for fabrication via a Stratasys Eden 260 printer in a flexible photopolymer to simulate arterial compliance. Fluoroscopic guided simulation of the patient-specific FEVAR procedure was performed by interventionists using all demonstration endografts and accessory devices. Analysis compared treatment strategy between the planned procedure, the simulation procedure, and the patient procedure using a derived scoring scheme. Results: With training on the patient-specific 3D printed AAA phantom, the clinical team optimized their procedural strategy. Anatomical landmarks and all devices were visible under x-ray during the simulation mimicking the clinical environment. The actual patient procedure went without complications. Conclusions: With advances in 3D printing, fabrication of patient specific AAA phantoms is possible. Simulation with 3D printed phantoms shows potential to inform clinical interventional procedures in addition to CTA diagnostic imaging.

  14. Single Project Replaces District's Windows.

    ERIC Educational Resources Information Center

    American School and University, 1981

    1981-01-01

    The towns of Maplewood and South Orange (New Jersey) earmarked over $1 million, raised from a bond issue, to replace with thermal aluminum-framed units the 2400 worn out windows in eight 50-year-old schools. (Author)

  15. Slab replacement maturity guidelines : [summary].

    DOT National Transportation Integrated Search

    2014-04-01

    Concrete sets in hours at moderate temperatures, : but the bonds that make concrete strong continue : to mature over days to years. However, for : replacement concrete slabs on highways, it is : crucial that concrete develop enough strength : within ...

  16. Options for Heart Valve Replacement

    MedlinePlus

    ... which may include human or animal donor tissue) Ross Procedure — “Borrowing” your healthy valve and moving it ... Considerations for Surgery Medications Valve Repair Valve Replacement - Ross Procedure - Newer Surgery Options - What is TAVR? - Types ...

  17. THE VASCULAR PATHOPHYSIOLOGY OF AN IRRADIATED GRAFT

    SciTech Connect

    Rubin, P.; Casarett, G.; Grise, J.W.

    1960-06-01

    The difference in the vascularization of grafted and normal skin forms a reasonable basis for explaining the differences in the radiation reactions of these structures. The radioisotope half time of disappearance following subcutaneous injection is an index of vascular integrity of the graft and serves as a parameter to predict its radioresponsiveness. In developing a concept of the spectrum of reactions of grafted skin to ionizing irradiation, knowledge of the radiopathologic changes in capillaries must be utilized with knowledge of the histophysiology of the vascularity of an autograft. (auth)

  18. Foam-rubber stents for skin grafts.

    PubMed

    Larson, P O

    1990-09-01

    A variety of stents are used to immobilize skin grafts and to hold them firmly to the recipient site. Tie-down stents, the most common type, are constructed from bulky, sterile dressing and are overtied with suture material. These stents are often cumbersome to apply. As an alternative, stents made from foam-rubber pads (Reston, 3M Company, St. Paul, MN) were stapled over skin grafts. These stents could be applied quickly, and they maintain continuous, uniform pressure on the immobilized grafts.

  19. Flow characteristics in narrowed coronary bypass graft

    SciTech Connect

    Bernad, S. I.; Bosioc, A.; Totorean, A. F.

    2016-06-08

    Tortuous saphenous vein graft (SVG) hemodynamics was investigated using computational fluid dynamics (CFD) techniques. Computed tomography (CT) technology is used for non-invasive bypass graft assessment 7 days after surgery. CT investigation shown two regions with severe shape remodelling first is an elbow type contortion and second is a severe curvature with tortuous area reduction. In conclusion, the helical flow induced by vessel torsion may stabilize the blood flow in the distal part of the SVG, reducing the flow disturbance and suppressing the flow separation, but in the distal end of the graft, promote the inflammatory processes in the vessels.

  20. Prioritization Methodology for Chemical Replacement

    NASA Technical Reports Server (NTRS)

    Cruit, W.; Schutzenhofer, S.; Goldberg, B.; Everhart, K.

    1993-01-01

    This project serves to define an appropriate methodology for effective prioritization of efforts required to develop replacement technologies mandated by imposed and forecast legislation. The methodology used is a semiquantitative approach derived from quality function deployment techniques (QFD Matrix). This methodology aims to weigh the full environmental, cost, safety, reliability, and programmatic implications of replacement technology development to allow appropriate identification of viable candidates and programmatic alternatives. The results are being implemented as a guideline for consideration for current NASA propulsion systems.

  1. Hot callusing for propagation of American beech by grafting

    Treesearch

    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...

  2. Impaction grafted bone chip size effect on initial stability in an acetabular model: Mechanical evaluation.

    PubMed

    Holton, Colin; Bobak, Peter; Wilcox, Ruth; Jin, Zhongmin

    2013-01-01

    Acetabular bone defect reconstruction is an increasing problem for surgeons with patients undergoing complex primary or revision total hip replacement surgery. Impaction bone grafting is one technique that has favourable long-term clinical outcome results for patients who undergo this reconstruction method for acetabular bone defects. Creating initial mechanical stability of the impaction bone graft in this technique is known to be the key factor in achieving a favourable implant survival rate. Different sizes of bone chips were used in this technique to investigate if the size of bone chips used affected initial mechanical stability of a reconstructed acetabulum. Twenty acetabular models were created in total. Five control models were created with a cemented cup in a normal acetabulum. Then five models in three different groups of bone chip size were constructed. The three groups had an acetabular protrusion defect reconstructed using either; 2-4 mm(3), 10 mm(3) or 20 mm(3) bone chip size for impaction grafting reconstruction. The models underwent compression loading up to 9500 N and displacement within the acetabular model was measured indicating the initial mechanical stability. This study reveals that, although not statistically significant, the largest (20 mm(3)) bone chip size grafted models have an inferior maximum stiffness compared to the medium (10 mm(3)) bone chip size. Our study suggests that 10 mm(3) size of bone chips provide better initial mechanical stability compared to smaller or larger bone chips. We dismissed the previously held opinion that the biggest practically possible graft is best for acetabular bone graft impaction.

  3. Comparison of the endurant bifurcated endograft vs. aortouni-iliac stent-grafting in patients with abdominal aortic aneurysms: experience from the ENGAGE registry.

    PubMed

    Tang, Tjun; Sadat, Umar; Walsh, Stewart; Hayes, Paul D

    2013-04-01

    To compare the 1-year outcomes after repair of abdominal aortic aneurysms (AAA) with the bifurcated vs. aortouni-iliac (AUI) configuration of the Endurant stent-graft. The study population comprised 1172 patients (1053 men; mean age 73.1±8.1 years, range 43-93) with unruptured infrarenal AAAs treated as part of the Endurant Stent Graft Natural Selection Global Post-market Registry (ENGAGE; ClinicalTrials.gov identifier NCT00870051). The primary outcome measure was treatment success at 12 months, defined by the composite of successful endograft deployment and the absence of type I/III endoleak, migration, rupture, or conversion to open surgery. Secondary outcome measures included endoleak, graft patency, migration, secondary procedures, and all-cause mortality. Among 1172 patients in ENGAGE, 1089 (92.9%) were treated with a bifurcated device and 83 (7.1%) received an AUI with femorofemoral bypass. Both groups were comparable with regard to demographics and baseline comorbidities, with the exception of a higher rate of cardiopulmonary disease in the AUI group. Successful deployment was achieved in all patients in the both groups. Postoperative complications occurred more frequently in the AUI patients, and the AUI group had an increased length of hospital stay (p=0.01). Endoleaks were more frequent in the AUI group at the conclusion of the procedure, a difference that vanished by 30 days. At 1 year, there were no incidences of graft kinking or stent fracture in either group. The rate of secondary procedures (5.3% in AUI patients and 4.9% for bifurcated cases) and all-cause mortality (10.5% and 8.6%, respectively) were similar in the two groups at 30 days and 1 year. The results of endovascular aneurysm repair with an Endurant AUI device appear similar to that after a bifurcated endovascular repair, with the exception of an increased length of hospital stay in the AUI group. An AUI device should be considered as an option in patients with anatomy unsuitable for a

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

    PubMed

    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.

  5. [Preparation of anti-hCG single domain antibody by antibody grafting technique using an antigen-binding peptide].

    PubMed

    Peng, Jing; Wang, Qiong; Cheng, Xiaoling; Liu, Mengwen; Wang, Mei; Xin, Huawei

    2018-04-25

    We used the antibody grafting technology to prepare anti-hCG single-domain antibodies on the basis of antigen-binding peptide to simplify the single-domain antibody preparation process and improving the biochemical stability of peptide. By using a universal single-domain antibody backbone (cAbBCII10), CDR1 or CDR3 was replaced by the hCG-binding peptide, and the grafted antibody gene sequences were synthesized and cloned into the prokaryotic expression vector pET30a(+) in fusion with a C-terminal sfGFP gene, i.e. pET30a-(His6)-cAbBCII10-CDR1/hCGBP1-sfGFP and pET30a-(His6)-cAbBCII10-CDR3/hCGBP3-sfGFP. The recombinant plasmids were transformed into E. coli BL21(DE3), and the fusion proteins were induced by IPTG. Highly soluble recombinant fusion proteins were obtained and purified by Ni-NTA affinity column. SDS-PAGE confirmed the purified protein as the target protein. The antigen-antibody binding assay showed that both the CDR1 and CDR3 grafted antibodies have hCG-binding activities. While the titers of the two grafted antibodies were similar, the binding affinity of CDR3 grafted antibody was higher than that of CDR1 grafted protein (about 2-3 times). The grafted antibodies retained the relatively high biochemical stability of the single-domain antibody backbone and were relatively thermostable and alkaline tolerant. The obtained antibodies also had a relatively high antigen-binding specificity to hCG. This study provided a reliable experimental basis for further optimization of anti-hCG single domain antibody by antibody grafting technology using antigen-binding peptide.

  6. Circulating Vascular Basement Membrane Fragments are Associated with the Diameter of the Abdominal Aorta and Their Expression Pattern is Altered in AAA Tissue.

    PubMed

    Holsti, Mari; Wanhainen, Anders; Lundin, Christina; Björck, Martin; Tegler, Gustaf; Svensson, Johan; Sund, Malin

    2018-04-12

    Abdominal aortic aneurysm (AAA) is characterised by enhanced proteolytic activity, and extracellular matrix (ECM) remodelling in the vascular wall. Type IV and XVIII collagen/endostatin are structural proteins in vascular basement membrane (VBM), a specialised ECM structure. Here the association between plasma levels of these collagens with the aortic diameter and expansion rate is studied, and their expression in aortic tissue characterised. This was a retrospective population based cohort study. Type IV and XVIII collagen/endostatin were analysed in plasma by ELISA assay in 615 men, divided into three groups based on the aortic diameter: 1) normal aorta ≤ 25 mm, 2) sub-aneurysmal aorta (SAA) 26-29 mm, and 3) AAA ≥ 30 mm. Follow up data were available for 159 men. The association between collagen levels and aortic diameter at baseline, and with the expansion rate at follow up were analysed in ordinal logistic regression and linear regression models, controlling for common confounding factors. Tissue expression of the collagens was analysed in normal aorta (n = 6) and AAA (n = 6) by immunofluorescence. Plasma levels of type XVIII collagen/endostatin (136 ng/mL [SD 29] in individuals with a normal aorta diameter, 154 ng/ml [SD 45] in SAA, and 162 ng/ml [SD 46] in AAA; p = .001) and type IV collagen (105 ng/mL [SD 42] normal aorta, 124 ng/ml [SD 46] SAA, and 127 ng/ml [SD 47] AAA; p = .037) were associated with a larger aortic diameter. A significant association was found between the baseline levels of type XVIII/endostatin and the aortic expansion rate (p = .035), but in the multivariable model, only the initial aortic diameter remained significantly associated with expansion (p = .005). Altered expression patterns of both collagens were observed in AAA tissue. Plasma levels of circulating type IV and XVIII collagen/endostatin increase with AAA diameter. The expression pattern of VBM proteins is altered in the aneurysm wall. Copyright

  7. SU-F-T-600: Influence of Acuros XB and AAA Dose Calculation Algorithms On Plan Quality Metrics and Normal Lung Doses in Lung SBRT

    SciTech Connect

    Yaparpalvi, R; Mynampati, D; Kuo, H

    Purpose: To study the influence of superposition-beam model (AAA) and determinant-photon transport-solver (Acuros XB) dose calculation algorithms on the treatment plan quality metrics and on normal lung dose in Lung SBRT. Methods: Treatment plans of 10 Lung SBRT patients were randomly selected. Patients were prescribed to a total dose of 50-54Gy in 3–5 fractions (10?5 or 18?3). Doses were optimized accomplished with 6-MV using 2-arcs (VMAT). Doses were calculated using AAA algorithm with heterogeneity correction. For each plan, plan quality metrics in the categories- coverage, homogeneity, conformity and gradient were quantified. Repeat dosimetry for these AAA treatment plans was performedmore » using AXB algorithm with heterogeneity correction for same beam and MU parameters. Plan quality metrics were again evaluated and compared with AAA plan metrics. For normal lung dose, V{sub 20} and V{sub 5} to (Total lung- GTV) were evaluated. Results: The results are summarized in Supplemental Table 1. PTV volume was mean 11.4 (±3.3) cm{sup 3}. Comparing RTOG 0813 protocol criteria for conformality, AXB plans yielded on average, similar PITV ratio (individual PITV ratio differences varied from −9 to +15%), reduced target coverage (−1.6%) and increased R50% (+2.6%). Comparing normal lung doses, the lung V{sub 20} (+3.1%) and V{sub 5} (+1.5%) were slightly higher for AXB plans compared to AAA plans. High-dose spillage ((V105%PD - PTV)/ PTV) was slightly lower for AXB plans but the % low dose spillage (D2cm) was similar between the two calculation algorithms. Conclusion: AAA algorithm overestimates lung target dose. Routinely adapting to AXB for dose calculations in Lung SBRT planning may improve dose calculation accuracy, as AXB based calculations have been shown to be closer to Monte Carlo based dose predictions in accuracy and with relatively faster computational time. For clinical practice, revisiting dose-fractionation in Lung SBRT to correct for dose

  8. Predictors of early graft failure after coronary artery bypass grafting for chronic total occlusion.

    PubMed

    Oshima, Hideki; Tokuda, Yoshiyuki; Araki, Yoshimori; Ishii, Hideki; Murohara, Toyoaki; Ozaki, Yukio; Usui, Akihiko

    2016-07-01

    Little is known regarding the transit-time flow measurement (TTFM) variables in grafts anastomosed to chronically totally occluded vessels (CTOs). We aimed to establish the TTFM cut-off values for detecting graft failure in bypass grafts anastomosed to chronically totally occluded arteries and clarify the relationship between early graft failure and the grade of collateral circulation/regional wall motion of the CTO territory. Among 491 patients who underwent isolated coronary artery bypass grafting (CABG) from 2009 to 2015, 196 cases with CTOs underwent postoperative coronary angiography within 1 month after CABG. Two hundred and forty-one CTOs in all patients were examined. Thirty-two CTOs (13%) were not bypassed and 214 conduits were anastomosed to CTOs and underwent intraoperative TTFM. Arterial conduits and saphenous vein grafts (SVGs) were used in 102 and 112 cases, respectively. Among the arterial conduit procedures that were performed, 78 involved the left internal thoracic artery (LITA), 10 involved the right internal thoracic artery (RITA) and 14 involved the right gastroepiploic artery (rGEA). Any graft showing Fitzgibbon type B or O lesions on angiography was considered to be a failing graft. The insufficiency rates for LITA, RITA, rGEA and SVG procedures were 5.1, 10, 14.3 and 7.1%, respectively. The TTFM variables recorded in failing grafts had a significantly lower mean flow (Qmean) and higher pulsatility index (PI) compared with patent grafts. Furthermore, akinetic or dyskinetic wall motion in the territory of bypassed CTOs was observed at a significantly higher rate in failing grafts. A multivariable regression analysis and receiver operating characteristic analysis revealed good predictors of early graft failure as follows: a Qmean value of < 11.5 ml/min for arterial conduits, a PI value of >5.85 and akinetic/dyskinetic wall motion in the CTO territory for SVGs. The Rentrop collateral grade was not associated with early graft failure. The Qmean

  9. Donor Indocyanine Green Clearance Test Predicts Graft Quality and Early Graft Prognosis After Liver Transplantation.

    PubMed

    Tang, Yunhua; Han, Ming; Chen, Maogen; Wang, Xiaoping; Ji, Fei; Zhao, Qiang; Zhang, Zhiheng; Ju, Weiqiang; Wang, Dongping; Guo, Zhiyong; He, Xiaoshun

    2017-11-01

    Transplantation centers have given much attention to donor availability. However, no reliable quantitative methods have been employed to accurately assess graft quality before transplantation. Here, we report that the indocyanine green (ICG) clearance test is a valuable index for liver grafts. We performed the ICG clearance test on 90 brain-dead donors within 6 h before organ procurement between March 2015 and November 2016. We also analyzed the relationship between graft liver function and early graft survival after liver transplantation (LT). Our results suggest that the ICG retention rate at 15 min (ICGR15) of donors before procurement was independently associated with 3-month graft survival after LT. The best donor ICGR15 cutoff value was 11.0%/min, and we observed a significant increase in 3-month graft failure among patients with a donor ICGR15 above this value. On the other hand, a donor ICGR15 value of ≤ 11.0%/min could be used as an early assessment index of graft quality because it provides additional information to the transplant surgeon or organ procurement organization members who must maintain or improve organ function to adapt the LT. An ICG clearance test before liver procurement might be an effective quantitative method to predict graft availability and improve early graft prognosis after LT.

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

    PubMed Central

    Guan, Ying; Wang, Lu; Lin, Jing; King, Martin W.

    2016-01-01

    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. PMID:28773781

  11. DNA nanosensor surface grafting and salt dependence

    NASA Astrophysics Data System (ADS)

    Carvalho, B. G.; Fagundes, J.; Martin, A. A.; Raniero, L.; Favero, P. P.

    2013-02-01

    In this paper we investigated the Paracoccidoides brasiliensis fungus nanosensor by simulations of simple strand DNA grafting on gold nanoparticle. In order to improve the knowledge of nanoparticle environment, the addiction of salt solution was studied at the models proposed by us. Nanoparticle and DNA are represented by economic models validated by us in this paper. In addition, the DNA grafting and salt influences are evaluated by adsorption and bond energies calculations. This theoretical evaluation gives support to experimental diagnostics techniques of diseases.

  12. A test of grafting ponderosa pine.

    Treesearch

    Edwin L. Mowat; Roy R. Silen

    1957-01-01

    Cleft grafting ponderosa pine proved best of five methods of vegetative propagation tested for field use in the dry hot climate of eastern Oregon. Ponderosa pine has been successfully grafted under many conditions elsewhere, but first trials in this area during 1955 were a failure. This study was made in 1956 at the U.S. Forest Service nursery at Bend, Oreg., to find a...

  13. Graft union formation in tomato plants: peroxidase and catalase involvement.

    PubMed

    Fernandez-Garcia, Nieves; Carvajal, Micaela; Olmos, Enrique

    2004-01-01

    The use of grafted plants in vegetable crop production is now being expanded greatly. However, few data are available on the formation of graft unions in vegetables. In this work, the structural development of the graft union formation in tomato plants is studied, together with the possible relationship with activities of peroxidases and catalases. Tomato (Lycopersicon esculentum Mill.) seedlings of cultivar Fanny were grafted on the rootstock of cultivar AR-9704 using the 'tongue approach grafting' method, and were grown in a crop chamber. A study of the structural development of the graft union and the involvement of peroxidases and catalases in the process of graft formation was carried out during the first stages of the graft union (4, 8 and 15 d after grafting). Observation of the structure of the graft union showed formation of xylem and phloem vessels through the graft union 8 d after grafting. In addition, root hydraulic conductance, L0, indicate that the graft union is fully functional 8 d after grafting, which coincided with an increase of peroxidase and catalase activities. These results suggest that increased peroxidase and catalase activities might be implicated in graft development in tomato plants.

  14. Photoacoustic detection of neovascularities in skin graft

    NASA Astrophysics Data System (ADS)

    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.

  15. Polypeptide Grafted Hyaluronan: Synthesis and Characterization

    SciTech Connect

    Wang, Xiaojun; Messman, Jamie M; Mays, Jimmy

    2010-01-01

    Poly(L-leucine) grafted hyaluronan (HA-g-PLeu) has been synthesized via a Michael addition reaction between primary amine terminated poly(L-leucine) and acrylate-functionalized HA (TBAHA-acrylate). The precursor hyaluronan was first functionalized with acrylate groups by reaction with acryloyl chloride in the presence of triethylamine in N,N-dimethylformamide. 1H NMR analysis of the resulting product indicated that an increase in the concentration of acryloylchoride with respect to hydroxyl groups on HA has only a moderate effect on functionalization efficiency, f. A precise control of stoichiometry was not achieved, which could be attributed to partial solubility of intermolecular aggregates and the hygroscopic nature of HA. Michael additionmore » at high [PLeu- NH2]/[acrylate]TBAHA ratios gave a molar grafting ratio of only 0.20 with respect to the repeat unit of HA, indicating grafting limitation due to insolubility of the grafted HA-g-PLeu. Soluble HA-g-PLeu graft copolymers were obtained for low grafting ratios (<0.039) with <8.6% by mass of PLeu and were characterized thoroughly using light scattering, 1H NMR, FT-IR, and AFM techniques. Light scattering experiments showed a strong hydrophobic interaction between PLeu chains, resulting in aggregates with segregated nongrafted HA segments. This yields local networks of aggregates, as demonstrated by atomic force microscopy. Circular dichroism spectroscopy showed a -sheet conformation for aggregates of poly(L-leucine).« less

  16. Tissue-engineered tracheal reconstruction using three-dimensionally printed artificial tracheal graft: preliminary report.

    PubMed

    Chang, Jae Won; Park, Su A; Park, Ju-Kyeong; Choi, Jae Won; Kim, Yoo-Suk; Shin, Yoo Seob; Kim, Chul-Ho

    2014-06-01

    Three-dimensional printing has come into the spotlight in the realm of tissue engineering. We intended to evaluate the plausibility of 3D-printed (3DP) scaffold coated with mesenchymal stem cells (MSCs) seeded in fibrin for the repair of partial tracheal defects. MSCs from rabbit bone marrow were expanded and cultured. A half-pipe-shaped 3DP polycaprolactone scaffold was coated with the MSCs seeded in fibrin. The half-pipe tracheal graft was implanted on a 10 × 10-mm artificial tracheal defect in four rabbits. Four and eight weeks after the operation, the reconstructed sites were evaluated bronchoscopically, radiologically, histologically, and functionally. None of the four rabbits showed any sign of respiratory distress. Endoscopic examination and computed tomography showed successful reconstruction of trachea without any collapse or blockage. The replaced tracheas were completely covered with regenerated respiratory mucosa. Histologic analysis showed that the implanted 3DP tracheal grafts were successfully integrated with the adjacent trachea without disruption or granulation tissue formation. Neo-cartilage formation inside the implanted graft was sufficient to maintain the patency of the reconstructed trachea. Scanning electron microscope examination confirmed the regeneration of the cilia, and beating frequency of regenerated cilia was not different from those of the normal adjacent mucosa. The shape and function of reconstructed trachea using 3DP scaffold coated with MSCs seeded in fibrin were restored successfully without any graft rejection. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  17. Aortic Root Reconstruction with a New Dacron Graft Featuring Prefabricated Coronary Side Branches

    PubMed Central

    Calcaterra, Domenico; Jazayeri, Mohammad-Ali; Turek, Joseph W.; Parekh, Kalpaj R.; Bashir, Mohammad; Karam, Karam; Farivar, Robert S.

    2017-01-01

    Background Coronary button reimplantation can represent a technical challenge of aortic root reconstruction that can be associated with significant morbidity and mortality. With the goal of simplifying coronary reimplantation and reducing the incidence of related complications, we designed a new Dacron graft with prefabricated coronary branches to minimize coronary artery mobilization and prevent the potential mechanical complications of reattachment to the body of the graft. Methods Between June 2010 and May 2012, we implanted the graft in eight patients (six males, two females) ranging in age from 42-68 years (mean, 54 years). Six procedures were modified Bentall reconstructions, and two procedures were valve-sparing root replacements using the reimplantation technique. Results There were no complications and no morbidity or mortality related to coronary reattachment. All patients were alive and doing well at a mean follow-up of 26 months (range, 17-38 months). At an extended mean follow-up of 42 months (range, 25-56 months), one patient died of stroke-related complications. No radiologic or clinical evidence of impairment of coronary perfusion was identified in any patient. Conclusions The use of this new graft model may simplify the technique of root reconstruction and potentially lower the incidence of mechanical complications related to coronary button reimplantation. PMID:28868309

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

    PubMed

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

    1985-09-01

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

  19. Osteochondral Tissue Cell Viability Is Affected by Total Impulse during Impaction Grafting

    PubMed Central

    Balash, Paul; Kang, Richard W.; Schwenke, Thorsten; Cole, Brian J.; Wimmer, Markus A.

    2010-01-01

    Objective: Osteochondral graft transplantation has garnered significant attention because of its ability to replace the lesion with true hyaline cartilage. However, surgical impaction of the graft to anchor it into the defect site can be traumatic and lead to cell death and cartilage degeneration. This study aimed to test the hypothesis that increasing impulse magnitude during impaction of osteochondral plugs has a direct effect on loss of cell viability. Design: In this controlled laboratory study, the impaction force was kept constant while the impulse was varied. Ninety-six osteochondral plugs were extracted from the trochlea of bovine stifle joints and were randomly assigned into 3 experimental and 1 (nonimpacted) control group. The transferred impulse of the experimental groups reflected the median and the lower and upper quartiles of preceding clinical measurements. Data were obtained at day 0, day 4, and day 8; at each point, cell viability was assessed using the Live/Dead staining kit and histological assessments were performed to visualize matrix structural changes. Results: After impaction, cartilage samples stayed intact and did not show any histological signs of matrix disruption. As expected, higher impulse magnitudes introduced more cell death; however, this relationship was lost at day 8 after impaction. Conclusion: Impulse magnitude has a direct effect on cell viability of the graft. Because impulse magnitude is mostly governed by the press-fit characteristics of the recipient site, this study aids in the definition of optimal insertion conditions for osteochondral grafts. PMID:26069558

  20. Prioritization methodology for chemical replacement

    NASA Technical Reports Server (NTRS)

    Cruit, Wendy; Goldberg, Ben; Schutzenhofer, Scott

    1995-01-01

    Since United States of America federal legislation has required ozone depleting chemicals (class 1 & 2) to be banned from production, The National Aeronautics and Space Administration (NASA) and industry have been required to find other chemicals and methods to replace these target chemicals. This project was initiated as a development of a prioritization methodology suitable for assessing and ranking existing processes for replacement 'urgency.' The methodology was produced in the form of a workbook (NASA Technical Paper 3421). The final workbook contains two tools, one for evaluation and one for prioritization. The two tools are interconnected in that they were developed from one central theme - chemical replacement due to imposed laws and regulations. This workbook provides matrices, detailed explanations of how to use them, and a detailed methodology for prioritization of replacement technology. The main objective is to provide a GUIDELINE to help direct the research for replacement technology. The approach for prioritization called for a system which would result in a numerical rating for the chemicals and processes being assessed. A Quality Function Deployment (QFD) technique was used in order to determine numerical values which would correspond to the concerns raised and their respective importance to the process. This workbook defines the approach and the application of the QFD matrix. This technique: (1) provides a standard database for technology that can be easily reviewed, and (2) provides a standard format for information when requesting resources for further research for chemical replacement technology. Originally, this workbook was to be used for Class 1 and Class 2 chemicals, but it was specifically designed to be flexible enough to be used for any chemical used in a process (if the chemical and/or process needs to be replaced). The methodology consists of comparison matrices (and the smaller comparison components) which allow replacement technology

  1. Estrogen and Progestin (Hormone Replacement Therapy)

    MedlinePlus

    ... progestin are two female sex hormones. Hormone replacement therapy works by replacing estrogen hormone that is no ... Progestin is added to estrogen in hormone replacement therapy to reduce the risk of uterine cancer in ...

  2. Long-term survival, valve durability, and reoperation for 4 aortic root procedures combined with ascending aorta replacement.

    PubMed

    Svensson, Lars G; Pillai, Saila T; Rajeswaran, Jeevanantham; Desai, Milind Y; Griffin, Brian; Grimm, Richard; Hammer, Donald F; Thamilarasan, Maran; Roselli, Eric E; Pettersson, Gösta B; Gillinov, A Marc; Navia, Jose L; Smedira, Nicholas G; Sabik, Joseph F; Lytle, Bruce W; Blackstone, Eugene H

    2016-03-01

    To evaluate long-term results of aortic root procedures combined with ascending aorta replacement for aneurysms, using 4 surgical strategies. From January 1995 to January 2011, 957 patients underwent 1 of 4 aortic root procedures: valve preservation (remodeling or modified reimplantation, n = 261); composite biologic graft (n = 297); composite mechanical graft (n = 156); or allograft root (n = 243). Seven deaths occurred (0.73%), none after valve-preserving procedures, and 13 strokes (1.4%). Composite grafts exhibited higher gradients than allografts or valve preservation, but the latter 2 exhibited more aortic regurgitation (2.7% biologic and 0% mechanical composite grafts vs 24% valve-preserving and 19% allografts at 10 years). Within 2 to 5 years, valve preservation exhibited the least left ventricular hypertrophy, allograft replacement the greatest; however, valve preservation had the highest early risk of reoperation, allograft replacement the lowest. Patients receiving allografts had the highest risk of late reoperation (P < .05), and those receiving composite mechanical grafts and valve preservation had the lowest. Composite bioprosthesis patients had the highest risk of late death (57% at 15 years vs 14%-26% for the remaining procedures, P < .0001), because they were substantially older and had more comorbidities (P < .0001). These 4 aortic root procedures, combined with ascending aorta replacement, provide excellent survival and good durability. Valve-preserving and allograft procedures have the lowest gradients and best ventricular remodeling, but they have more late regurgitation, and likely, less risk of valve-related complications, such as bleeding, hemorrhage, and endocarditis. Despite the early risk of reoperation, we recommend valve-preserving procedures for young patients when possible. Composite bioprostheses are preferable for the elderly. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights

  3. Effects of combination therapy using basic fibroblast growth factor and mature adipocyte-derived dedifferentiated fat (DFAT) cells on skin graft revascularisation.

    PubMed

    Asami, Takashi; Soejima, Kazutaka; Kashimura, Tsutomu; Kazama, Tomohiko; Matsumoto, Taro; Morioka, Kosuke; Nakazawa, Hiroaki

    2015-01-01

    Although the benefits of basic fibroblast growth factor (bFGF) for wound healing and angiogenesis are well known, its effects on the process of skin graft revascularisation have not been clarified. It was hypothesised that bFGF would be beneficial to promote taking of skin grafts, but that the effect might be limited in the case of bFGF monotherapy. Therefore, this study investigated the efficacy of combination therapy using bFGF and dedifferentiated fat (DFAT) cells. DFAT cells have multilineage differentiation potential, including into endothelial cells, similar to the case of mesenchymal stem cells (MSC). Commercially available human recombinant bFGF was used. DFAT cells were prepared from SD strain rats as an adipocyte progenitor cell line from mature adipocytes. Full-thickness skin was lifted from the back of SD strain rats and then grafted back to the original wound site. Four groups were established prior to skin grafting: control group (skin graft alone), bFGF group (treated with bFGF), DFAT group (treated with DFAT cells), and combination group (treated with both bFGF and DFAT cells). Tissue specimens for histological examination were harvested 48 hours after grafting. The histological findings for the bFGF group showed vascular augmentation in the grafted dermis compared with the control group. However, the difference in the number of revascularised vessels per unit area did not reach statistical significance against the control group. In contrast, in the combination group, skin graft revascularisation was significantly promoted, especially in the upper dermis. The results suggest that replacement of the existing graft vessels was markedly promoted by the combination therapy using bFGF and DFAT cells, which may facilitate skin graft taking.

  4. Cobra Probes Containing Replaceable Thermocouples

    NASA Technical Reports Server (NTRS)

    Jones, John; Redding, Adam

    2007-01-01

    A modification of the basic design of cobra probes provides for relatively easy replacement of broken thermocouples. Cobra probes are standard tube-type pressure probes that may also contain thermocouples and that are routinely used in wind tunnels and aeronautical hardware. They are so named because in side views, they resemble a cobra poised to attack. Heretofore, there has been no easy way to replace a broken thermocouple in a cobra probe: instead, it has been necessary to break the probe apart and then rebuild it, typically at a cost between $2,000 and $4,000 (2004 prices). The modified design makes it possible to replace the thermocouple, in minimal time and at relatively low cost, by inserting new thermocouple wire in a tube.

  5. Bridging Graft in Irreparable Massive Rotator Cuff Tears: Autogenic Biceps Graft versus Allogenic Dermal Patch Graft

    PubMed Central

    Rhee, Sung Min

    2017-01-01

    Background Few comparative studies have reported on the use of biologic grafts for irreparable massive rotator cuff tears. The purpose of this study was to assess the results of arthroscopic bridging graft in irreparable massive rotator cuff tears using an autogenic long head of biceps tendon (LHBT) or an allogenic dermal patch (ADP). Methods We retrospectively reviewed 24 patients treated using the LHBT (group I) and eight patients with complete rupture of the LHBT treated using an ADP (group II) since 2011. Preoperative Goutallier's fatty degeneration, range of motion (ROM), visual analogue scale (VAS) for pain, American Shoulder and Elbow Surgeons (ASES) score, and Quick Disabilities of the Arm, Shoulder, and Hand (DASH) score were assessed and healing failure was evaluated at 1 year after surgery by ultrasonography or magnetic resonance imaging. Results The mean fatty degeneration in groups I and II was 3.9 and 3.6 for the supraspinatus (p = 0.288), 2.7 and 2.9 for the infraspinatus (p = 0.685), 0.9 and 1.3 for the subscapularis (p = 0.314), and 1.3 and 3.0 for the teres minor (p = 0.005), respectively. Subscapularis tears were found in 8 patients (33.3%) in group I and in 7 patients (87.5%) in group II (p = 0.023). Mean ROMs and functional scores improved significantly in group I (forward flexion: 121.7° to 153.3°, p = 0.010; external rotation: 32.7° to 52.7°, p = 0.001; external rotation at 90°: 63.3° to 74.5°, p = 0.031; internal rotation: T10.5 to T9.3, p = 0.045; VAS: 7.0 to 1.1, p < 0.001; ASES score: 45.4 to 81.6, p = 0.028; and Quick DASH score: 50.0 to 14.2, p = 0.017), whereas only VAS showed significant improvement in group II (from 5.9 to 2.0, p = 0.025) and ROMs and other functional scores increased without statistical significance in the group. Healing failure was found in 13 patients (54.2%) in group I and in 6 patients (75.0%) in group II (p = 0.404). Conclusions The surgeon should prudently choose surgical options for irreparable massive

  6. Bridging Graft in Irreparable Massive Rotator Cuff Tears: Autogenic Biceps Graft versus Allogenic Dermal Patch Graft.

    PubMed

    Rhee, Sung Min; Oh, Joo Han

    2017-12-01

    Few comparative studies have reported on the use of biologic grafts for irreparable massive rotator cuff tears. The purpose of this study was to assess the results of arthroscopic bridging graft in irreparable massive rotator cuff tears using an autogenic long head of biceps tendon (LHBT) or an allogenic dermal patch (ADP). We retrospectively reviewed 24 patients treated using the LHBT (group I) and eight patients with complete rupture of the LHBT treated using an ADP (group II) since 2011. Preoperative Goutallier's fatty degeneration, range of motion (ROM), visual analogue scale (VAS) for pain, American Shoulder and Elbow Surgeons (ASES) score, and Quick Disabilities of the Arm, Shoulder, and Hand (DASH) score were assessed and healing failure was evaluated at 1 year after surgery by ultrasonography or magnetic resonance imaging. The mean fatty degeneration in groups I and II was 3.9 and 3.6 for the supraspinatus ( p = 0.288), 2.7 and 2.9 for the infraspinatus ( p = 0.685), 0.9 and 1.3 for the subscapularis ( p = 0.314), and 1.3 and 3.0 for the teres minor ( p = 0.005), respectively. Subscapularis tears were found in 8 patients (33.3%) in group I and in 7 patients (87.5%) in group II ( p = 0.023). Mean ROMs and functional scores improved significantly in group I (forward flexion: 121.7° to 153.3°, p = 0.010; external rotation: 32.7° to 52.7°, p = 0.001; external rotation at 90°: 63.3° to 74.5°, p = 0.031; internal rotation: T10.5 to T9.3, p = 0.045; VAS: 7.0 to 1.1, p < 0.001; ASES score: 45.4 to 81.6, p = 0.028; and Quick DASH score: 50.0 to 14.2, p = 0.017), whereas only VAS showed significant improvement in group II (from 5.9 to 2.0, p = 0.025) and ROMs and other functional scores increased without statistical significance in the group. Healing failure was found in 13 patients (54.2%) in group I and in 6 patients (75.0%) in group II ( p = 0.404). The surgeon should prudently choose surgical options for irreparable massive rotator cuff tears, especially

  7. Molecular replacement: tricks and treats

    SciTech Connect

    Abergel, Chantal, E-mail: chantal.abergel@igs.cnrs-mrs.fr

    2013-11-01

    To be successful, molecular replacement relies on the quality of the model and of the crystallographic data. Some tricks that could be applied to the models or to the crystal to increase the success rate of MR are discussed here. Molecular replacement is the method of choice for X-ray crystallographic structure determination provided that suitable structural homologues are available in the PDB. Presently, there are ∼80 000 structures in the PDB (8074 were deposited in the year 2012 alone), of which ∼70% have been solved by molecular replacement. For successful molecular replacement the model must cover at least 50% ofmore » the total structure and the C{sub α} r.m.s.d. between the core model and the structure to be solved must be less than 2 Å. Here, an approach originally implemented in the CaspR server (http://www.igs.cnrs-mrs.fr/Caspr2/index.cgi) based on homology modelling to search for a molecular-replacement solution is discussed. How the use of as much information as possible from different sources can improve the model(s) is briefly described. The combination of structural information with distantly related sequences is crucial to optimize the multiple alignment that will define the boundaries of the core domains. PDB clusters (sequences with ≥30% identical residues) can also provide information on the eventual changes in conformation and will help to explore the relative orientations assumed by protein subdomains. Normal-mode analysis can also help in generating series of conformational models in the search for a molecular-replacement solution. Of course, finding a correct solution is only the first step and the accuracy of the identified solution is as important as the data quality to proceed through refinement. Here, some possible reasons for failure are discussed and solutions are proposed using a set of successful examples.« less

  8. Circumferential Esophageal Replacement by a Tissue-engineered Substitute Using Mesenchymal Stem Cells

    PubMed Central

    Catry, Jonathan; Luong-Nguyen, Minh; Arakelian, Lousineh; Poghosyan, Tigran; Bruneval, Patrick; Domet, Thomas; Michaud, Laurent; Sfeir, Rony; Gottrand, Frederic; Larghero, Jerome; Vanneaux, Valerie

    2018-01-01

    Tissue engineering appears promising as an alternative technique for esophageal replacement. Mesenchymal stem cells (MSCs) could be of interest for esophageal regeneration. Evaluation of the ability of an acellular matrix seeded with autologous MSCs to promote tissue remodeling toward an esophageal phenotype after circumferential replacement of the esophagus in a mini pig model. A 3 cm long circumferential replacement of the abdominal esophagus was performed with an MSC-seeded matrix (MSC group, n = 10) versus a matrix alone (control group, n = 10), which has previously been matured into the great omentum. The graft area was covered with an esophageal removable stent. A comparative histological analysis of the graft area after animals were euthanized sequentially is the primary outcome of the study. Histological findings after maturation, overall animal survival, and postoperative morbidity were also compared between groups. At postoperative day 45 (POD 45), a mature squamous epithelium covering the entire surface of the graft area was observed in all the MSC group specimens but in none of the control group before POD 95. Starting at POD 45, desmin positive cells were seen in the graft area in the MSC group but never in the control group. There were no differences between groups in the incidence of surgical complications and postoperative death. In this model, MSCs accelerate the mature re-epitheliazation and early initiation of muscle cell colonization. Further studies will focus on the use of cell tracking tools in order to analyze the becoming of these cells and the mechanisms involved in this tissue regeneration. PMID:29390879

  9. Prioritization methodology for chemical replacement

    NASA Technical Reports Server (NTRS)

    Goldberg, Ben; Cruit, Wendy; Schutzenhofer, Scott

    1995-01-01

    This methodology serves to define a system for effective prioritization of efforts required to develop replacement technologies mandated by imposed and forecast legislation. The methodology used is a semi quantitative approach derived from quality function deployment techniques (QFD Matrix). QFD is a conceptual map that provides a method of transforming customer wants and needs into quantitative engineering terms. This methodology aims to weight the full environmental, cost, safety, reliability, and programmatic implications of replacement technology development to allow appropriate identification of viable candidates and programmatic alternatives.

  10. HST Replacement Battery Initial Performance

    NASA Technical Reports Server (NTRS)

    Krol, Stan; Waldo, Greg; Hollandsworth, Roger

    2009-01-01

    The Hubble Space Telescope (HST) original Nickel-Hydrogen (NiH2) batteries were replaced during the Servicing Mission 4 (SM4) after 19 years and one month on orbit.The purpose of this presentation is to highlight the findings from the assessment of the initial sm4 replacement battery performance. The batteries are described, the 0 C capacity is reviewed, descriptions, charts and tables reviewing the State Of Charge (SOC) Performance, the Battery Voltage Performance, the battery impedance, the minimum voltage performance, the thermal performance, the battery current, and the battery system recharge ratio,

  11. Treatment of Venous Aortorenal Bypass Graft Aneurysm Using a Stent-Graft

    SciTech Connect

    Novotny, Jiri, E-mail: jino@medicon.cz; Peregrin, Jan H.; Stribrna, Jarmila

    2010-02-15

    We present the case of a 77-year-old male patient who had undergone a bilateral venous aortorenal bypass graft 30 years previously. Thirteen years previously, the patient was shown to have a decrease in renal function, with mild shrinking of both kidneys; additionally, a stenosis was found in the left proximal anastomosis. At the most recent follow-up visit (1 year previously), ultrasound revealed an aneurysm (42 mm in diameter) of the left renal bypass graft; the finding was confirmed by CT angiography. A significant ostial stenosis of the left renal bypass graft was also confirmed. It was decided to place amore » self-expandable stent-graft into the aneurysm while also attempting to dilate the stenosis. Proximal endoleak after stent-graft placement necessitated the implantation of another, balloon-expandable stent-graft into the bypass graft ostium. Postprocedural angiography and follow-up by CT angiography at 3 months confirmed good patency of the stent-grafts and complete thrombosis of the aneurysmal sac, with preserved kidney perfusion. Renal function remained unaltered, while the hypertension is better controlled.« less

  12. Physical properties of agave cellulose graft polymethyl methacrylate

    SciTech Connect

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim

    2013-11-27

    The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm{sup −1} which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity indexmore » upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one.« less

  13. Substrate delivery by the AAA+ ClpX and ClpC1 unfoldases activates the mycobacterial ClpP1P2 peptidase

    PubMed Central

    Schmitz, Karl R.; Sauer, Robert T.

    2014-01-01

    Summary Mycobacterial Clp-family proteases function via collaboration of the heteromeric ClpP1P2 peptidase with a AAA+ partner, ClpX or ClpC1. These enzymes are essential for M. tuberculosis viability and are validated antibacterial drug targets, but the requirements for assembly and regulation of functional proteolytic complexes are poorly understood. Here, we report the reconstitution of protein degradation by mycobacterial Clp proteases in vitro and describe novel features of these enzymes that distinguish them from orthologs in other bacteria. Both ClpX and ClpC1 catalyze ATP-dependent unfolding and degradation of native protein substrates in conjunction with ClpP1P2, but neither mediates protein degradation with just ClpP1 or ClpP2. ClpP1P2 alone has negligible peptidase activity, but is strongly stimulated by translocation of protein substrates into ClpP1P2 by either AAA+ partner. Interestingly, our results support a model in which both binding of a AAA+ partner and protein-substrate delivery are required to stabilize active ClpP1P2. Our model has implications for therapeutically targeting ClpP1P2 in dormant M. tuberculosis, and our reconstituted systems should facilitate identification of novel Clp protease inhibitors and activators. PMID:24976069

  14. Point Mutations in the Stem Region and the Fourth AAA Domain of Cytoplasmic Dynein Heavy Chain Partially Suppress the Phenotype of NUDF/LIS1 Loss in Aspergillus nidulans

    PubMed Central

    Zhuang, Lei; Zhang, Jun; Xiang, Xin

    2007-01-01

    Cytoplasmic dynein performs multiple cellular tasks but its regulation remains unclear. The dynein heavy chain has a N-terminal stem that binds to other subunits and a C-terminal motor unit that contains six AAA (ATPase associated with cellular activities) domains and a microtubule-binding site located between AAA4 and AAA5. In Aspergillus nidulans, NUDF (a LIS1 homolog) functions in the dynein pathway, and two nudF6 partial suppressors were mapped to the nudA dynein heavy chain locus. Here we identified these two mutations. The nudAL1098F mutation resides in the stem region, and nudAR3086C is in the end of AAA4. These mutations partially suppress the phenotype of nudF deletion but do not suppress the phenotype exhibited by mutants of dynein intermediate chain and Arp1. Surprisingly, the stronger ΔnudF suppressor, nudAR3086C, causes an obvious decrease in the basal level of dynein's ATPase activity and an increase in dynein's distribution along microtubules. Thus, suppression of the ΔnudF phenotype may result from mechanisms other than simply the enhancement of dynein's ATPase activity. The fact that a mutation in the end of AAA4 negatively regulates dynein's ATPase activity but partially compensates for NUDF loss indicates the importance of the AAA4 domain in dynein regulation in vivo. PMID:17237507

  15. Hemolytic anemia caused by aortic flap and inversion of felt strip after ascending aorta replacement.

    PubMed

    Sakaguchi, Masayuki; Takano, Tamaki

    2016-08-02

    Hemolysis related to a kinked prosthetic graft or inner felt strip is a very rare complication after aortic surgery. We describe herein a case of hemolytic anemia that developed due to aortic flap of the dissection and inversion of an inner felt strip that was applied at the proximal anastomosis of a replaced ascending aorta 10 years previously. A 74-year-old woman presented with consistent hemolytic anemia 10 years after replacement of the ascending aorta to treat Stanford type A acute aortic dissection. The cause of hemolysis was attributed to mechanical injury of red blood cells at a site of stenosis caused by aortic flap of the dissection and inversion of the felt strip used for the proximal anastomosis. Repeated resection of the strip and graft replacement of the ascending aorta resolved this problem. We considered that blood flow disrupted by a jet of blood at the site of the proximal inner felt strip was the cause of severe hemolysis, we describe rare hemolytic anemia at the site of aortic flap and inverted felt strip after replacement of the ascending aorta.

  16. Micropatterned nanostructures: a bioengineered approach to mass-produce functional myocardial grafts.

    PubMed

    Serpooshan, Vahid; Mahmoudi, Morteza

    2015-02-13

    Cell-based therapies are a recently established path for treating a wide range of human disease. Tissue engineering of contractile heart muscle for replacement therapy is among the most exciting and important of these efforts. However, current in vitro techniques of cultivating functional mature cardiac grafts have only been moderately successful due to the poor capability of traditional two-dimensional cell culture systems to recapitulate necessary in vivo conditions. In this issue, Kiefer et al introduce a laser-patterned nanostructured substrate (Al/Al2O3 nanowires) for efficient maintenance of oriented human cardiomyocytes, with great potential to open new roads to mass-production of contractile myocardial grafts for cardiovascular tissue engineering.

  17. Micropatterned nanostructures: a bioengineered approach to mass-produce functional myocardial grafts

    NASA Astrophysics Data System (ADS)

    Serpooshan, Vahid; Mahmoudi, Morteza

    2015-02-01

    Cell-based therapies are a recently established path for treating a wide range of human disease. Tissue engineering of contractile heart muscle for replacement therapy is among the most exciting and important of these efforts. However, current in vitro techniques of cultivating functional mature cardiac grafts have only been moderately successful due to the poor capability of traditional two-dimensional cell culture systems to recapitulate necessary in vivo conditions. In this issue, Kiefer et al [1] introduce a laser-patterned nanostructured substrate (Al/Al2O3 nanowires) for efficient maintenance of oriented human cardiomyocytes, with great potential to open new roads to mass-production of contractile myocardial grafts for cardiovascular tissue engineering.

  18. Reconstructive surgery with chin block graft and esthetic rehabilitation of missing anterior tooth.

    PubMed

    Bansal, Preetika; Bansal, Pardeep

    2014-03-01

    The complete and predictable restoration of the periodontium following infection or trauma remains a critical objective in regenerative therapy. Bone grafts remain among the most widely used therapeutic strategies for the correction of periodontal osseous defects. For periodontally compromised anterior teeth, reconstruction of the ridge along with natural tooth pontic serves both the purpose of regeneration and esthetics. The right lower central incisor of a 28-year-old male that was periodontally compromised was extracted. Autogenous chin grafting followed by retrograde surgery of the extracted tooth and replacement by natural tooth pontic was done. After 6 months, there was significant improvement in clinical picture and bone fill. This procedure provided excellent regenerative and esthetic results for the periodontally compromised lost anterior tooth.

  19. The AAA protein Msp1 mediates clearance of excess tail-anchored proteins from the peroxisomal membrane

    PubMed Central

    Weir, Nicholas R; Kamber, Roarke A; Martenson, James S

    2017-01-01

    Msp1 is a conserved AAA ATPase in budding yeast localized to mitochondria where it prevents accumulation of mistargeted tail-anchored (TA) proteins, including the peroxisomal TA protein Pex15. Msp1 also resides on peroxisomes but it remains unknown how native TA proteins on mitochondria and peroxisomes evade Msp1 surveillance. We used live-cell quantitative cell microscopy tools and drug-inducible gene expression to dissect Msp1 function. We found that a small fraction of peroxisomal Pex15, exaggerated by overexpression, is turned over by Msp1. Kinetic measurements guided by theoretical modeling revealed that Pex15 molecules at mitochondria display age-independent Msp1 sensitivity. By contrast, Pex15 molecules at peroxisomes are rapidly converted from an initial Msp1-sensitive to an Msp1-resistant state. Lastly, we show that Pex15 interacts with the peroxisomal membrane protein Pex3, which shields Pex15 from Msp1-dependent turnover. In sum, our work argues that Msp1 selects its substrates on the basis of their solitary membrane existence. PMID:28906250

  20. Random amplified polymorphic DNA (RAPD) detection of dwarf off-types in micropropagated Cavendish (Musa spp. AAA) bananas.

    PubMed

    Damasco, O P; Graham, G C; Henry, R J; Adkins, S W; Smiths, M K; Godwin, I D

    1996-11-01

    A RAPD marker specific to the dwarf off-type (hereafter known as dwarf) from micropropagation of Cavendish banana (Musa spp. AAA) cultivars New Guinea Cavendish and Williams was identified following an analysis of 57 normal (true-to-type) and 59 dwarf plants generated from several different micropropagation events. Sixty-six random decamer primers were used in the initial screen, of which 19 (28.8%) revealed polymorphisms between normal and dwarf plants. Primer OPJ-04 (5'-CCGAACACGG-3') was found to amplify an approx. 1.5 kb band which was consistently present in all normal but absent in all dwarf plants of both cultivars. Reliable detection of dwarf plants was achieved using this marker, providing the only available means ofin vitro detection of dwarfs. The use of this marker could facilitate early detection and elimination of dwarfs from batches of micropropagated bananas, and may be a useful tool in determining what factors in the tissue culture process lead to this off type production.Other micropropagation-induced RAPD polymorphisms were observed but were not associated with the dwarf trait.

  1. Ultrastructural changes and the distribution of arabinogalactan proteins during somatic embryogenesis of banana (Musa spp. AAA cv. 'Yueyoukang 1').

    PubMed

    Pan, Xiao; Yang, Xiao; Lin, Guimei; Zou, Ru; Chen, Houbin; Samaj, Jozef; Xu, Chunxiang

    2011-08-01

    A better understanding of somatic embryogenesis in banana (Musa spp.) may provide a practical way to improve regeneration of banana plants. In this study, we applied scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to visualize the ultrastructural changes during somatic embryogenesis of banana (Musa AAA cv. 'Yueyoukang 1'). We also used histological and immunohistochemical techniques with 16 monoclonal antibodies to study the spatial distribution and cellular/subcellular localization of different arabinogalactan protein (AGP) components of the cell wall during somatic embryogenesis. Histological study with periodic acid-Schiff staining documented diverse embryogenic stages from embryogenic cells (ECs) to the late embryos. SEM revealed a mesh-like structure on the surface of proembryos which represented an early structural marker of somatic embryogenesis. TEM showed that ECs were rich in juvenile mitochondria, endoplasmic reticulum and Golgi stacks. Cells in proembryos and early globular embryos resembled ECs, but they were more vacuolated, showed more regular nuclei and slightly more developed organelles. Immunocytochemical study revealed that the signal of most AGP epitopes was stronger in starch-rich cells when compared with typical ECs. The main AGP component in the extracellular matrix surface network of banana proembryos was the MAC204 epitope. Later, AGP immunolabelling patterns varied with the developmental stages of the embryos. These results about developmental regulation of AGP epitopes along with developmental changes in the ultrastructure of cells are providing new insights into the somatic embryogenesis of banana. Copyright © Physiologia Plantarum 2011.

  2. In-situ monitoring of blood glucose level for dialysis machine by AAA-battery-size ATR Fourier spectroscopy

    NASA Astrophysics Data System (ADS)

    Hosono, Satsuki; Sato, Shun; Ishida, Akane; Suzuki, Yo; Inohara, Daichi; Nogo, Kosuke; Abeygunawardhana, Pradeep K.; Suzuki, Satoru; Nishiyama, Akira; Wada, Kenji; Ishimaru, Ichiro

    2015-07-01

    For blood glucose level measurement of dialysis machines, we proposed AAA-battery-size ATR (Attenuated total reflection) Fourier spectroscopy in middle infrared light region. The proposed one-shot Fourier spectroscopic imaging is a near-common path and spatial phase-shift interferometer with high time resolution. Because numerous number of spectral data that is 60 (= camera frame rare e.g. 60[Hz]) multiplied by pixel number could be obtained in 1[sec.], statistical-averaging improvement realize high-accurate spectral measurement. We evaluated the quantitative accuracy of our proposed method for measuring glucose concentration in near-infrared light region with liquid cells. We confirmed that absorbance at 1600[nm] had high correlations with glucose concentrations (correlation coefficient: 0.92). But to measure whole-blood, complex light phenomenon caused from red blood cells, that is scattering and multiple reflection or so, deteriorate spectral data. Thus, we also proposed the ultrasound-assisted spectroscopic imaging that traps particles at standing-wave node. Thus, if ATR prism is oscillated mechanically, anti-node area is generated around evanescent light field on prism surface. By elimination complex light phenomenon of red blood cells, glucose concentration in whole-blood will be quantify with high accuracy. In this report, we successfully trapped red blood cells in normal saline solution with ultrasonic standing wave (frequency: 2[MHz]).

  3. Structural insights into the Escherichia coli lysine decarboxylases and molecular determinants of interaction with the AAA+ ATPase RavA

    PubMed Central

    Kandiah, Eaazhisai; Carriel, Diego; Perard, Julien; Malet, Hélène; Bacia, Maria; Liu, Kaiyin; Chan, Sze W. S.; Houry, Walid A.; Ollagnier de Choudens, Sandrine; Elsen, Sylvie; Gutsche, Irina

    2016-01-01

    The inducible lysine decarboxylase LdcI is an important enterobacterial acid stress response enzyme whereas LdcC is its close paralogue thought to play mainly a metabolic role. A unique macromolecular cage formed by two decamers of the Escherichia coli LdcI and five hexamers of the AAA+ ATPase RavA was shown to counteract acid stress under starvation. Previously, we proposed a pseudoatomic model of the LdcI-RavA cage based on its cryo-electron microscopy map and crystal structures of an inactive LdcI decamer and a RavA monomer. We now present cryo-electron microscopy 3D reconstructions of the E. coli LdcI and LdcC, and an improved map of the LdcI bound to the LARA domain of RavA, at pH optimal for their enzymatic activity. Comparison with each other and with available structures uncovers differences between LdcI and LdcC explaining why only the acid stress response enzyme is capable of binding RavA. We identify interdomain movements associated with the pH-dependent enzyme activation and with the RavA binding. Multiple sequence alignment coupled to a phylogenetic analysis reveals that certain enterobacteria exert evolutionary pressure on the lysine decarboxylase towards the cage-like assembly with RavA, implying that this complex may have an important function under particular stress conditions. PMID:27080013

  4. The Pch2 AAA+ ATPase promotes phosphorylation of the Hop1 meiotic checkpoint adaptor in response to synaptonemal complex defects

    PubMed Central

    Herruzo, Esther; Ontoso, David; González-Arranz, Sara; Cavero, Santiago; Lechuga, Ana; San-Segundo, Pedro A.

    2016-01-01

    Meiotic cells possess surveillance mechanisms that monitor critical events such as recombination and chromosome synapsis. Meiotic defects resulting from the absence of the synaptonemal complex component Zip1 activate a meiosis-specific checkpoint network resulting in delayed or arrested meiotic progression. Pch2 is an evolutionarily conserved AAA+ ATPase required for the checkpoint-induced meiotic block in the zip1 mutant, where Pch2 is only detectable at the ribosomal DNA array (nucleolus). We describe here that high levels of the Hop1 protein, a checkpoint adaptor that localizes to chromosome axes, suppress the checkpoint defect of a zip1 pch2 mutant restoring Mek1 activity and meiotic cell cycle delay. We demonstrate that the critical role of Pch2 in this synapsis checkpoint is to sustain Mec1-dependent phosphorylation of Hop1 at threonine 318. We also show that the ATPase activity of Pch2 is essential for its checkpoint function and that ATP binding to Pch2 is required for its localization. Previous work has shown that Pch2 negatively regulates Hop1 chromosome abundance during unchallenged meiosis. Based on our results, we propose that, under checkpoint-inducing conditions, Pch2 also possesses a positive action on Hop1 promoting its phosphorylation and its proper distribution on unsynapsed chromosome axes. PMID:27257060

  5. The Pch2 AAA+ ATPase promotes phosphorylation of the Hop1 meiotic checkpoint adaptor in response to synaptonemal complex defects.

    PubMed

    Herruzo, Esther; Ontoso, David; González-Arranz, Sara; Cavero, Santiago; Lechuga, Ana; San-Segundo, Pedro A

    2016-09-19

    Meiotic cells possess surveillance mechanisms that monitor critical events such as recombination and chromosome synapsis. Meiotic defects resulting from the absence of the synaptonemal complex component Zip1 activate a meiosis-specific checkpoint network resulting in delayed or arrested meiotic progression. Pch2 is an evolutionarily conserved AAA+ ATPase required for the checkpoint-induced meiotic block in the zip1 mutant, where Pch2 is only detectable at the ribosomal DNA array (nucleolus). We describe here that high levels of the Hop1 protein, a checkpoint adaptor that localizes to chromosome axes, suppress the checkpoint defect of a zip1 pch2 mutant restoring Mek1 activity and meiotic cell cycle delay. We demonstrate that the critical role of Pch2 in this synapsis checkpoint is to sustain Mec1-dependent phosphorylation of Hop1 at threonine 318. We also show that the ATPase activity of Pch2 is essential for its checkpoint function and that ATP binding to Pch2 is required for its localization. Previous work has shown that Pch2 negatively regulates Hop1 chromosome abundance during unchallenged meiosis. Based on our results, we propose that, under checkpoint-inducing conditions, Pch2 also possesses a positive action on Hop1 promoting its phosphorylation and its proper distribution on unsynapsed chromosome axes. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  6. Developments in parallel grafts for aortic arch lesions.

    PubMed

    Kolvenbach, Ralf R; Rabin, Asaf; Karmeli, Ron; Alpaslan, Alper; Schwierz, Elizabeth

    2016-06-01

    Due to the shortage of commercially available off the shelf aortic arch grafts since the last years parallel grafts or chimney grafts have played an increasing role in the treatment of patients with aortic arch lesions. Although there are still issues with type endoleaks and gutters between the chimney graft and the aortic stent-graft remaining. We report our results with the Medtronic thoracic graft in combination with long self-expanding parallel grafts, to ensure an overlapping zone of more than 7 cm between the different grafts. Alternatively, sandwich configurations are used where a direct contact between the parallel graft and the aortic wall is avoided. We have placed a total of 65 parallel grafts into supra-aortic branches. In 21 cases chimney grafts were placed into the carotid artery, in most cases into the left common carotid artery. In 36 cases chimney grafts were placed into left subclavian artery. A maximum number of 4 parallel grafts were placed for total endovascular debranching. In addition, in 8 patients a parallel graft had to be placed into the innominate artery. There was a patency of 69% for all subclavian artery chimney grafts versus 73% for carotid artery parallel grafts. Of note is a stroke rate of 5.2% in all these cases. Only 2 of the patients with an occluded left subclavian artery chimney graft required a bypass procedure for arm claudication or ischemia. We had a primary type I endoleak rate of 28%. In almost 25% secondary interventions were required mainly to treat type I leaks, in those cases where the leak did not resolve spontaneously. The overall mortality rate was 3.5%. The results of parallel graft in the aortic arch are promising, but of major concern is still the high rate of type I endoleaks as well as the neurological complication rate, most probably due to catheter manipulation in patients with severe atherosclerotic arch lesions.

  7. The use of biological grafts for reconstruction of the inferior vena cava is a safe and valid alternative: results in 32 patients in a single institution

    PubMed Central

    Pulitanó, Carlo; Crawford, Michael; Ho, Phong; Gallagher, James; Joseph, David; Stephen, Michael; Sandroussi, Charbel

    2013-01-01

    Background Resection and reconstruction of the inferior vena cava (IVC) is occasionally required in the surgical treatment of intra-abdominal tumours. IVC reconstruction can be performed with biological or synthetic graft material, with most centres preferring synthetic grafts. In spite of the potential advantages of biological grafts in terms of handling characteristics, and safety, very limited data are available about their use in patients requiring an IVC resection. Methods Medical records of 32 patients who underwent an IVC resection and reconstruction from 1990 and 2011 with autogenous peritoneo-fascial (N = 22) and bovine pericardial (N = 10) grafts were reviewed. Results A tangential resection with patch repair was performed in 10 patients, whereas in the remaining 22 it was necessary to resect and replace a segment or all of the retrohepatic IVC. A concomitant liver resection was performed in 14 patients, nephrectomy in 10 and pancreaticoduodenectomy in 2 patients. There were no acute or late complications related to graft thrombosis or infection. Three patients died as a consequence of multi-organ failure. Overall survival at 1 and 5 years was 78% and 48%, respectively. Conclusions The preferential use of synthetic grafts in IVC replacement is not evidence based. Selection of an appropriate prosthetic graft for IVC reconstruction should be based on the safety and its handling features. The use of biological grafts for IVC repair is a valid alternative to current synthetic materials and may in fact be superior in terms of biocompatability, ease of handling, reduced rate of infection and improved long-term patency without permanent anticoagulation. PMID:23458108

  8. The use of biological grafts for reconstruction of the inferior vena cava is a safe and valid alternative: results in 32 patients in a single institution.

    PubMed

    Pulitanó, Carlo; Crawford, Michael; Ho, Phong; Gallagher, James; Joseph, David; Stephen, Michael; Sandroussi, Charbel

    2013-08-01

    Resection and reconstruction of the inferior vena cava (IVC) is occasionally required in the surgical treatment of intra-abdominal tumours. IVC reconstruction can be performed with biological or synthetic graft material, with most centres preferring synthetic grafts. In spite of the potential advantages of biological grafts in terms of handling characteristics, and safety, very limited data are available about their use in patients requiring an IVC resection. Medical records of 32 patients who underwent an IVC resection and reconstruction from 1990 and 2011 with autogenous peritoneo-fascial (N = 22) and bovine pericardial (N = 10) grafts were reviewed. A tangential resection with patch repair was performed in 10 patients, whereas in the remaining 22 it was necessary to resect and replace a segment or all of the retrohepatic IVC. A concomitant liver resection was performed in 14 patients, nephrectomy in 10 and pancreaticoduodenectomy in 2 patients. There were no acute or late complications related to graft thrombosis or infection. Three patients died as a consequence of multi-organ failure. Overall survival at 1 and 5 years was 78% and 48%, respectively. The preferential use of synthetic grafts in IVC replacement is not evidence based. Selection of an appropriate prosthetic graft for IVC reconstruction should be based on the safety and its handling features. The use of biological grafts for IVC repair is a valid alternative to current synthetic materials and may in fact be superior in terms of biocompatability, ease of handling, reduced rate of infection and improved long-term patency without permanent anticoagulation. © 2013 International Hepato-Pancreato-Biliary Association.

  9. Testing of Replacement Bag Material

    SciTech Connect

    Laurinat, J.E.

    1998-11-03

    Recently, the FB-Line bagout material was changed to simplify the processing of sand, slag, and crucible.The results of the strength tests and the outgassing measurements and calculations demonstrate that the proposed replacement nylon bag materials (HRMP and orange anti-static material) are acceptable substitutes for LDPE and the original nylon with respect to mechanical properties.

  10. MELFI-3 Electronic Unit Replacement

    NASA Image and Video Library

    2011-07-01

    ISS028-E-013797 (1 July 2011) --- NASA astronaut Mike Fossum, Expedition 28 flight engineer, replaces a failed electronic unit for the Minus Eighty Laboratory Freezer for ISS 3 (MELFI-3) with a spare unit in the Kibo laboratory of the International Space Station.

  11. MELFI-3 Electronic Unit Replacement

    NASA Image and Video Library

    2011-07-01

    ISS028-E-013799 (1 July 2011) --- NASA astronaut Mike Fossum, Expedition 28 flight engineer, replaces a failed electronic unit for the Minus Eighty Laboratory Freezer for ISS 3 (MELFI-3) with a spare unit in the Kibo laboratory of the International Space Station.

  12. A numerical study of the effect of catheter angle on the blood flow characteristics in a graft during hemodialysis

    NASA Astrophysics Data System (ADS)

    Ryou, Hong Sun; Kim, Soyoon; Ro, Kyoungchul

    2013-02-01

    For patients with renal failure, renal replacement therapies are needed. Hemodialysis is a widely used renal replacement method to remove waste products. It is important to improve the patency rate of the vascular access for efficient dialysis. Since some complications such as an intimal hyperplasia are associated with the flow pattern, the hemodynamics in the vascular access must be considered to achieve a high patency rate. In addition, the blood flow from an artificial kidney affects the flow in the vascular access. Generally, the clinical techniques of hemodialysis such as the catheter angle or dialysis dose have been set up empirically. In this study, a numerical analysis is performed on the effect of the catheter angle on the flow in the graft. Blood is assumed to be a non-Newtonian fluid. According to the high average wall shear stress value, the leucocytes and platelets can be activated not only at the arterial anastomosis, but also at the bottom of the venous graft, when the catheter angle is not zero. For a catheter angle less than five degrees, there is a low shear and high oscillatory shear index region that appears at the venous graft and the venous anastomosis. Thus, a catheter angle less than five degrees should be avoided to prevent graft failure.

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

    SciTech Connect

    Lenton, James, E-mail: jlenton@doctors.org.u; Davies, John; Homer-Vanniasinkam, S.

    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 withmore » stent-grafts has not been previously reported in the adolescent population.« less

  14. Corneal graft reversal: Histopathologic report of two cases

    PubMed Central

    Qahtani, Abdullah A.; Alkatan, Hind M.

    2014-01-01

    Graft reversal is a rare cause for failed PKP. In this case report we are presenting 2 graft failure cases in which the corneal grafts were reversed unintentionally. The onset of signs of graft failure, however was variable. We have included their clinical course and the histopathologic findings of the removed corneal grafts. A total of 6 cases including ours have been reported so far. The aim of this report is to attract the attention of corneal surgeons to an additional rare cause for failed penetrating keratoplasty (PKP) which is donor graft reversal. PMID:25473355

  15. Corneal graft reversal: Histopathologic report of two cases.

    PubMed

    Qahtani, Abdullah A; Alkatan, Hind M

    2014-10-01

    Graft reversal is a rare cause for failed PKP. In this case report we are presenting 2 graft failure cases in which the corneal grafts were reversed unintentionally. The onset of signs of graft failure, however was variable. We have included their clinical course and the histopathologic findings of the removed corneal grafts. A total of 6 cases including ours have been reported so far. The aim of this report is to attract the attention of corneal surgeons to an additional rare cause for failed penetrating keratoplasty (PKP) which is donor graft reversal.

  16. Homologous gene replacement in Physarum

    SciTech Connect

    Burland, T.G.; Pallotta, D.

    1995-01-01

    The protist Physarum polycephalum is useful for analysis of several aspects of cellular and developmental biology. To expand the opportunities for experimental analysis of this organism, we have developed a method for gene replacement. We transformed Physarum amoebae with plasmid DNA carrying a mutant allele, ardD{Delta}1, of the ardD actin gene; ardD{Delta}1 mutates the critical carboxy-terminal region of the gene product. Because ardD is not expressed in the amoeba, replacement of ardD{sup +} with ardD{Delta}1 should not be lethal for this cell type. Transformants were obtained only when linear plasmid DNA was used. Most transformants carried one copy of ardD{Delta}1more » in addition to ardD{sup +}, but in two (5%), ardD{sup +} was replaced by a single copy of ardD{Delta}1. This is the first example of homologous gene replacement in Physarum. ardD{Delta}1 was stably maintained in the genome through growth, development and meiosis. We found no effect of ardD{Delta}l on viability, growth, or development of any of the various cell types of Physarum. Thus, the carboxy-terminal region of the ardD product appears not to perform a unique essential role in growth or development. Nevertheless, this method for homologous gene replacement can be applied to analyze the function of any cloned gene. 38 refs., 6 figs., 1 tab.« less

  17. Use of bovine pericardial tissue for aortic valve and aortic root replacement: long-term results.

    PubMed

    Vrandecic, M; Gontijo Filho, B; Fantini, F; Barbosa, J; Martins, I; de Oliveira, O C; Martins, C; Max, R; Drumond, L; Oliveira, C; Ferrufino, A; Alcocer, E; Silva, J A; Vrandecic, E

    1998-03-01

    The study aimed to determine the clinical performance of bovine pericardial aldehyde-treated products alone or in combination with aortic leaflets of porcine origin. These included a composite porcine stentless aortic valve attached to a scalloped pericardial tube (BSAV), and valved and non-valved bovine pericardial conduits for use in left-sided heart lesions (BPG). For BSAV grafts, between January 1990 and August 1996, 163 patients (119 males) had their aortic valves replaced by SJM Biocor BASV. Mean age was 37.9 +/- 17.6 years (range: 1 to 76 years). Rheumatic heart disease sequelae (n = 72) and replacement of a prosthetic heart valve (n = 46) were predominant. Preoperative NYHA functional class showed 90 patients (55.2%) in class III and 50 (30.7%) in class IV. BPVC and NVPC grafts were used in 166 patients: acute aortic dissection was the main indication in 52 (31.3%) and chronic in 36 (21/7%). The ascending aorta was involved in 141 patients (84.9%); grafts were seldom used at other sites. In most patients the graft implanted was either a non-valved (n = 79) or a valved (n = 75) pericardial conduit. Twelve patients had a localized lesion and required a patch repair. For BASV grafts, the non-valve-related hospital mortality rate was 4.9%. There were 14.7% non-fatal complications with full recovery of all patients. Mean follow up in 141 patients was 3.0 +/- 1.4 years (range: 1 month to 7.2 years); 14 patients were lost to follow up. Late, non-conduit-related, mortality occurred in seven patients (4.9%). Eight patients underwent reoperation. The current clinical follow up of 127 patients has shown 118 (92.9%) with competent valves and nine (7.0%) with mild stable aortic insufficiency. For BPVC and NVPC grafts, hospital mortality rate was 16.9%, death being related to poor preoperative clinical condition. Postoperative follow up was accomplished in 125 patients; reoperation was necessary in seven patients. Histology showed good tissue preservation up to five

  18. Resection of recurrent neck cancer with carotid artery replacement.

    PubMed

    Illuminati, Giulio; Schneider, Fabrice; Minni, Antonio; Calio, Francesco G; Pizzardi, Giulia; Ricco, Jean-Baptiste

    2016-05-01

    tumors (n = 14; QALYs, 1.29; P = .032). Aggressive en bloc resection of recurrent neck cancer with PTFE grafting can be curative in patients without metastases at the time of redo surgery. In this subset of patients, extensive neck surgery with carotid artery replacement can lead to excellent local control of the disease with improved quality of survival. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

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

    PubMed

    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 < 0.01). The authors can confirm neither of the suggested arguments, for or against full-thickness 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.

  20. Cell therapy of hip osteonecrosis with autologous bone marrow grafting.

    PubMed

    Hernigou, Philippe; Poignard, Alexandre; Zilber, Sebastien; Rouard, Hélène

    2009-01-01

    One of the reasons for bone remodeling leading to an insufficient creeping substitution after osteonecrosis in the femoral head may be the small number of progenitor cells in the proximal femur and the trochanteric region. Because of this lack of progenitor cells, treatment modalities should stimulate and guide bone remodeling to sufficient creeping substitution to preserve the integrity of the femoral head. Core decompression with bone graft is used frequently in the treatment of osteonecrosis of the femoral head. In the current series, grafting was done with autologous bone marrow obtained from the iliac crest of patients operated on for early stages of osteonecrosis of the hip before collapse with the hypothesis that before stage of subchondral collapse, increasing the number of progenitor cells in the proximal femur will stimulate bone remodeling and creeping substitution and thereby improve functional outcome. Between 1990 and 2000, 342 patients (534 hips) with avascular osteonecrosis at early stages (Stages I and II) were treated with core decompression and autologous bone marrow grafting obtained from the iliac crest of patients operated on for osteonecrosis of the hip. The percentage of hips affected by osteonecrosis in this series of 534 hips was 19% in patients taking corticosteroids, 28% in patients with excessive alcohol intake, and 31% in patients with sickle cell disease. The mean age of the patients at the time of decompression and autologous bone marrow grafting was 39 years (range: 16-61 years). The aspirated marrow was reduced in volume by concentration and injected into the femoral head after core decompression with a small trocar. To measure the number of progenitor cells transplanted, the fibroblast colony forming unit was used as an indicator of the stroma cell activity. Patients were followed up from 8 to 18 years. The outcome was determined by the changes in the Harris hip score, progression in radiographic stages, change in volume

  1. Texture analysis of computed tomographic images in osteoporotic patients with sinus lift bone graft reconstruction.

    PubMed

    Marchand-Libouban, Hélène; Guillaume, Bernard; Bellaiche, Norbert; Chappard, Daniel

    2013-05-01

    Bone implants are now widely used to replace missing teeth. Bone grafting (sinus lift) is a very useful way to increase the bone volume of the maxilla in patients with bone atrophy. There is a 6- to 9-month delay for the receiver grafted site to heal before the implants can be placed. Computed tomography is a useful method to measure the amount of remaining bone before implantation and to evaluate the quality of the receiver bone at the end of the healing period. Texture analysis is a non-invasive method useful to characterize bone microarchitecture on X-ray images. Ten patients in which a sinus lift surgery was necessary before implantation were analyzed in the present study. All had a bone reconstruction with a combination of a biomaterial (beta tricalcium phosphate) and autograft bone harvested at the chin. Computed tomographic images were obtained before grafting (t0), at mid-interval (t1, 4.2 ± 0.7 months) and before implant placement (t2, 9.2 ± 0.6 months). Texture analysis was done with the run-length method. A significant increase of texture parameters at t1 reflected a gain of homogeneity due to the graft and the beginning of bone remodeling. At t2, some parameters remained high and corresponded to the persistence of bone trabeculae while the resorption of biomaterials was identified by other parameters which tended to return to pregraft values. Texture analysis identified changes during the healing of the receiver site. The method is known to correlate with microarchitectural changes in bone and could be a useful approach to characterized osseointegrated grafts.

  2. Computer-based planning of optimal donor sites for autologous osseous grafts

    NASA Astrophysics Data System (ADS)

    Krol, Zdzislaw; Chlebiej, Michal; Zerfass, Peter; Zeilhofer, Hans-Florian U.; Sader, Robert; Mikolajczak, Pawel; Keeve, Erwin

    2002-05-01

    Bone graft surgery is often necessary for reconstruction of craniofacial defects after trauma, tumor, infection or congenital malformation. In this operative technique the removed or missing bone segment is filled with a bone graft. The mainstay of the craniofacial reconstruction rests with the replacement of the defected bone by autogeneous bone grafts. To achieve sufficient incorporation of the autograft into the host bone, precise planning and simulation of the surgical intervention is required. The major problem is to determine as accurately as possible the donor site where the graft should be dissected from and to define the shape of the desired transplant. A computer-aided method for semi-automatic selection of optimal donor sites for autografts in craniofacial reconstructive surgery has been developed. The non-automatic step of graft design and constraint setting is followed by a fully automatic procedure to find the best fitting position. In extension to preceding work, a new optimization approach based on the Levenberg-Marquardt method has been implemented and embedded into our computer-based surgical planning system. This new technique enables, once the pre-processing step has been performed, selection of the optimal donor site in time less than one minute. The method has been applied during surgery planning step in more than 20 cases. The postoperative observations have shown that functional results, such as speech and chewing ability as well as restoration of bony continuity were clearly better compared to conventionally planned operations. Moreover, in most cases the duration of the surgical interventions has been distinctly reduced.

  3. Experimental verification of the Acuros XB and AAA dose calculation adjacent to heterogeneous media for IMRT and RapidArc of nasopharygeal carcinoma.

    PubMed

    Kan, Monica W K; Leung, Lucullus H T; So, Ronald W K; Yu, Peter K N

    2013-03-01

    To compare the doses calculated by the Acuros XB (AXB) algorithm and analytical anisotropic algorithm (AAA) with experimentally measured data adjacent to and within heterogeneous medium using intensity modulated radiation therapy (IMRT) and RapidArc(®) (RA) volumetric arc therapy plans for nasopharygeal carcinoma (NPC). Two-dimensional dose distribution immediately adjacent to both air and bone inserts of a rectangular tissue equivalent phantom irradiated using IMRT and RA plans for NPC cases were measured with GafChromic(®) EBT3 films. Doses near and within the nasopharygeal (NP) region of an anthropomorphic phantom containing heterogeneous medium were also measured with thermoluminescent dosimeters (TLD) and EBT3 films. The measured data were then compared with the data calculated by AAA and AXB. For AXB, dose calculations were performed using both dose-to-medium (AXB_Dm) and dose-to-water (AXB_Dw) options. Furthermore, target dose differences between AAA and AXB were analyzed for the corresponding real patients. The comparison of real patient plans was performed by stratifying the targets into components of different densities, including tissue, bone, and air. For the verification of planar dose distribution adjacent to air and bone using the rectangular phantom, the percentages of pixels that passed the gamma analysis with the ± 3%/3mm criteria were 98.7%, 99.5%, and 97.7% on the axial plane for AAA, AXB_Dm, and AXB_Dw, respectively, averaged over all IMRT and RA plans, while they were 97.6%, 98.2%, and 97.7%, respectively, on the coronal plane. For the verification of planar dose distribution within the NP region of the anthropomorphic phantom, the percentages of pixels that passed the gamma analysis with the ± 3%/3mm criteria were 95.1%, 91.3%, and 99.0% for AAA, AXB_Dm, and AXB_Dw, respectively, averaged over all IMRT and RA plans. Within the NP region where air and bone were present, the film measurements represented the dose close to unit density water

  4. Bovine and PTFE vascular graft results in hemodialysis patients.

    PubMed

    Sert, S; Demirogullari, B; Ziya Anadol, A; Guvence, N; Dalgic, A

    2000-01-01

    Purpose. There are many reports of patency periods, failure rates, thrombosis and infection attacks connected with vascular grafts. In this article, the results of polytetrafluoroethylene (PTFE) and Bovine grafts were compared in a forty-four month period. Methods. 61 vascular grafts (29 PTFE, 32 bovine) were placed in 49 patients. The grafts were compared in different ways, such as survival, complication rates and placement area using life survey analysis. Results. Mean survival time was 17 mo (SE +/- 2.8) for PTFE grafts and 11 mo (SE +/- 1.1) for bovine grafts. A failure rate of 34% due only to graft complications were found in PTFE and 25% in bovine grafts. All graft complications were seen in the first year. Comparison of the cumulative survival rates of the groups were found to be insignificant during the study period and the first year ( p>0.05). Regardless of the type, there was no signif-icant difference between the grafts placed in the forearm and the grafts in the thigh (p>0.05). Conclusions. There is no survival difference between PTFE and bovine grafts. First year of the grafts is important for developing complications.

  5. <