959 resultados para Surgical flap grafts
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Objective:
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Left ventricular pressure overload in response to aortic banding is an invaluable model for studying progression of cardiac hypertrophy and transition to heart failure. Traditional aortic banding has recently been superceded by minimally invasive transverse aortic banding (MTAB) which does not require ventilation so is less technically challenging. Although the MTAB procedure is superior, few laboratories have documented success and minimal information on the model is available. The aim of this study was to optimise conditions for MTAB and to characterise the development and progression of cardiac hypertrophy. Isofluorane proved the most suitable anaesthetic for MTAB surgery in mice and one week after surgery MTAB animals showed significant increases in systolic blood pressure (110±6 v's 78±3(mmHg), MTAB v's sham, n=7,p
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The long-term success of arterial bypass grafting with autologous saphenous veins is limited by neointimal hyperplasia (NIH), which seemingly develops preferentially at sites where hydrodynamic wall shear is low. Placement of a loose-fitting, porous stent around end-to-end, or end-to-side, autologous saphenous vein grafts on the porcine common carotid artery has been found significantly to reduce NIH, but the mechanism is unclear. In a preliminary study, we implanted autologous saphenous vein grafts bilaterally on the common carotid arteries of pigs, placing a stent around one graft and leaving the contralateral graft unstented. At sacrifice 1 month post implantation, the grafts were pressure fixed in situ and resin casts were made. Unstented graft geometry was highly irregular, with non-uniform dilatation, substantial axial lengthening, curvature, kinking, and possible long-pitch helical distortion. In contrast, stented grafts showed no major dilatation, lengthening or curvature, but there was commonly fine corrugation, occasional slight kinking or narrowing of segments, and possible long-pitch helical distortion. Axial growth of grafts against effectively tethered anastomoses could account for these changes. CFD studies are planned, using 3D MR reconstructions, on the effects of graft geometry on the flow. Abnormality of the flow could favour the development of vascular pathology, including NIH.
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Rationale: Smooth muscle cells (SMCs) are a key component of tissue-engineered vessels. However, the sources by which they can be isolated are limited.
Objective: We hypothesized that a large number of SMCs could be obtained by direct reprogramming of fibroblasts, that is, direct differentiation of specific cell lineages before the cells reaching the pluripotent state.
Methods and Results: We designed a combined protocol of reprogramming and differentiation of human neonatal lung fibroblasts. Four reprogramming factors (OCT4, SOX2, KLF4, and cMYC) were overexpressed in fibroblasts under reprogramming conditions for 4 days with cells defined as partially-induced pluripotent stem (PiPS) cells. PiPS cells did not form tumors in vivo after subcutaneous transplantation in severe combined immunodeficiency mice and differentiated into SMCs when seeded on collagen IV and maintained in differentiation media. PiPS-SMCs expressed a panel of SMC markers at mRNA and protein levels. Furthermore, the gene dickkopf 3 was found to be involved in the mechanism of PiPS-SMC differentiation. It was revealed that dickkopf 3 transcriptionally regulated SM22 by potentiation of Wnt signaling and interaction with Kremen1. Finally, PiPS-SMCs repopulated decellularized vessel grafts and ultimately gave rise to functional tissue-engineered vessels when combined with previously established PiPS-endothelial cells, leading to increased survival of severe combined immunodeficiency mice after transplantation of the vessel as a vascular graft.
Conclusions: We developed a protocol to generate SMCs from PiPS cells through a dickkopf 3 signaling pathway, useful for generating tissue-engineered vessels. These findings provide a new insight into the mechanisms of SMC differentiation with vast therapeutic potential.
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Purpose: To describe a new surgical approach in the management of pseudophakic malignant glaucoma. Design: Noncomparative case series. Participants: Five consecutive patients with pseudophakic malignant glaucoma. Methods: All patients underwent zonulo-hyaloido-vitrectomy. The procedure involves the performance of zonulectomy, hyaloidectomy, and anterior vitrectomy (zonulo-hyaloido-vitrectomy) through a peripheral iridectomy or iridotomy via the anterior chamber. Main Outcome Measures: Medications, visual acuity, intraocular pressure, and anterior and posterior segment findings were recorded before and after surgery. Results: Resolution of the malignant glaucoma was achieved in all cases. No recurrences were observed after a median follow-up of 5.5 months (range, 1-9 months). In one patient with extensive anterior synechiae, bleb failure occurred after the resolution of the malignant glaucoma. This patient was treated successfully with a guarded filtration procedure supplemented with 5-fluorouracil. No other complications were observed. Conclusions: Zonulo-hyaloido-vitrectomy via the anterior segment appears to be an alternative option in the treatment of patients with pseudophakic malignant glaucoma. © 2001 by the American Academy of Ophthalmology.
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Purpose: To compare long-term cognitive outcomes of patients treated with surgical clipping or endovascular coiling after subarachnoid haemorrhage (SAH). Method: Retrospective matched cohort study assessed neuropsychological functioning at least 12 months after aneurysmal SAH treatment. Fourteen patients treated by endovascular coiling and nine patients treated by surgical clipping participated. After gaining written consent, a comprehensive neuropsychological battery was completed. Standardised tests were employed to assess pre-morbid and current intellectual functioning (IQ), attention, speed of information processing, memory and executive function as well as psychosocial functioning and affect. Results: Treatment groups were not significantly different in terms of age, pre-morbid IQ, time from injury to treatment or time since injury. A significant effect of treatment on full-scale IQ score (p = 0.025), performance IQ (p = 0.045) and verbal IQ score (p = 0.029), all favouring the coiled group was observed. A medium effect size between groups difference in immediate memory (p = 0.19, partial ?(2) = 0.08) was also observed. No significant between group differences on attention, executive functioning and speed of information processing measures or mood and psychosocial functioning were noted. Both groups reported increased anxiety and memory, attention and speed of information processing deficits relative to normative data. Conclusions: Study findings indicate fewer cognitive deficits following endovascular coiling. Cognitive deficits in the clipped group may be due in part to the invasive nature of neurosurgical clipping. Further prospective research with regard to long-term cognitive and emotional outcomes is warranted. [Box: see text].
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BACKGROUND: Open angle glaucoma (OAG) is a common cause of blindness.
OBJECTIVES: To assess the effects of medication compared with initial surgery in adults with OAG.
SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 7), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to August 2012), EMBASE (January 1980 to August 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to August 2012), Biosciences Information Service (BIOSIS) (January 1969 to August 2012), Cumulative Index to Nursing and Allied Health Literature (CINAHL) (January 1937 to August 2012), OpenGrey (System for Information on Grey Literature in Europe) (www.opengrey.eu/), Zetoc, the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 1 August 2012. The National Research Register (NRR) was last searched in 2007 after which the database was archived. We also checked the reference lists of articles and contacted researchers in the field.
SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing medications with surgery in adults with OAG.
DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted data. We contacted study authors for missing information.
MAIN RESULTS: Four trials involving 888 participants with previously untreated OAG were included. Surgery was Scheie's procedure in one trial and trabeculectomy in three trials. In three trials, primary medication was usually pilocarpine, in one trial it was a beta-blocker.The most recent trial included participants with on average mild OAG. At five years, the risk of progressive visual field loss, based on a three unit change of a composite visual field score, was not significantly different according to initial medication or initial trabeculectomy (odds ratio (OR) 0.74, 95% confidence interval (CI) 0.54 to 1.01). In an analysis based on mean difference (MD) as a single index of visual field loss, the between treatment group difference in MD was -0.20 decibel (dB) (95% CI -1.31 to 0.91). For a subgroup with more severe glaucoma (MD -10 dB), findings from an exploratory analysis suggest that initial trabeculectomy was associated with marginally less visual field loss at five years than initial medication, (mean difference 0.74 dB (95% CI -0.00 to 1.48). Initial trabeculectomy was associated with lower average intraocular pressure (IOP) (mean difference 2.20 mmHg (95% CI 1.63 to 2.77) but more eye symptoms than medication (P = 0.0053). Beyond five years, visual acuity did not differ according to initial treatment (OR 1.48, 95% CI 0.58 to 3.81).From three trials in more severe OAG, there is some evidence that medication was associated with more progressive visual field loss and 3 to 8 mmHg less IOP lowering than surgery. In the longer-term (two trials) the risk of failure of the randomised treatment was greater with medication than trabeculectomy (OR 3.90, 95% CI 1.60 to 9.53; hazard ratio (HR) 7.27, 95% CI 2.23 to 25.71). Medications and surgery have evolved since these trials were undertaken.In three trials the risk of developing cataract was higher with trabeculectomy (OR 2.69, 95% CI 1.64 to 4.42). Evidence from one trial suggests that, beyond five years, the risk of needing cataract surgery did not differ according to initial treatment policy (OR 0.63, 95% CI 0.15 to 2.62).Methodological weaknesses were identified in all the trials.
AUTHORS' CONCLUSIONS: Primary surgery lowers IOP more than primary medication but is associated with more eye discomfort. One trial suggests that visual field restriction at five years is not significantly different whether initial treatment is medication or trabeculectomy. There is some evidence from two small trials in more severe OAG, that initial medication (pilocarpine, now rarely used as first line medication) is associated with more glaucoma progression than surgery. Beyond five years, there is no evidence of a difference in the need for cataract surgery according to initial treatment.The clinical and cost-effectiveness of contemporary medication (prostaglandin analogues, alpha2-agonists and topical carbonic anhydrase inhibitors) compared with primary surgery is not known.Further RCTs of current medical treatments compared with surgery are required, particularly for people with severe glaucoma and in black ethnic groups. Outcomes should include those reported by patients. Economic evaluations are required to inform treatment policy.