Publications by authors named "Alexander Seifalian"

Tissue engineering has been conducted in the study of cardiovascular grafts for many years. Many obstacles have been overcome in this rapidly changing field, but one difficulty has remained until now: the large number of endothelial cells (ECs) needed for seeding the inner layer of bypass graft. Recent advances in endothelial progenitor cell (EPC) isolation and culture techniques have increased the interest in genetic studies.

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Lacrimal surgery in cases of severely obstructed or missing canalicular ducts is highly challenging. In these cases, the placement of a bypass tube is currently the only option to restore the drainage of tears into the nose and reduce the symptomatic watery eye. Different approaches to achieve functional drainage have been tried using blood vessels or artificial implants.

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Human peripheral blood (HPB) contains both circulating endothelial cells (CECs) and endothelial progenitor stem cells (EPCs), which may be suitable for use in regenerative medicine. There has been considerable interest in using these cells, but there is no "gold standard" technique for isolating these cells. The aim of this study was to characterize and compare a number of different extraction and culture techniques to develop a system to isolate and culture cells.

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Surface modification using plasma processing can significantly change the chemical and physical characteristics of biomaterial surfaces. When used in combination with additional modification techniques such as direct chemical or biochemical methods, it can produce novel biomaterial surfaces, which are anticoagulant, bioactive, and biomimetic in nature. This article reviews recent advances in improving hemocompatibility of biomaterials by plasma surface modification (PSM).

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Repairing nerve defects with large gaps remains one of the most operative challenges for surgeons. Incomplete recovery from peripheral nerve injuries can produce a diversity of negative outcomes, including numbness, impairment of sensory or motor function, possibility of developing chronic pain, and devastating permanent disability. In the last few years, numerous microsurgical techniques, such as coaptation, nerve autograft, and different biological or polymeric nerve conduits, have been developed to reconstruct a long segment of damaged peripheral nerve.

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Cancer is one of the main causes of death in the world, and according to the WHO it is projected to continue rising. Current diagnostic modalities for the detection of cancer include the use of x-rays, magnetic resonance imaging and positron emission tomography, among others. The treatment of cancer often involves the use (or combination) of chemotherapeutic drugs, radiotherapy and interventional surgery (for solid and operable tumors).

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Tacrolimus (FK506) is a widely used immunosuppressant in organ transplantation. However, it also has neurotrophic activity that occurs independently of its immunosuppressive effects. Other neurotrophic immunophilin ligands that do not exhibit immunosuppression have subsequently been developed and studied in various models of nerve injury.

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Interstitial lung disease (ILD) in systemic sclerosis (scleroderma) is a rare and potentially lethal and devastating autoimmune disease, and yet the cause of it remains poorly understood. It is associated with tissue fibrosis not only in the lungs, but also other organs like the heart and kidneys. Although ILD can manifest itself in various disease presentations, ILD in systemic sclerosis is particularly and especially worrying because it has the highest case-specific mortality among all autoimmune rheumatic conditions.

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Nanotechnology is a new and exciting branch of science which offers enormous potential for development of medicine and surgery. Gold nanoparticles (GNP) is just one of a variety of nano products which will be available for physician of the future. GNP will give us more effective treatments and diagnosis.

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There is a significant worldwide demand for a small calibre vascular graft for use as a bypass or replacement conduit. An important feature in determining the success of a graft is the wall structure, which includes porosity, pore size and pore interconnectivity, as these play a crucial role in determining the long-term patency of a bypass graft. In this study we fabricate a small diameter (<5mm) vascular graft from polyhedral oligomeric silsesquioxane-poly(carbonate urea)urethane (POSS-PCU) via an extrusion, phase inversion method using an automated, custom built machine.

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Artificial nerve conduits offer an attractive alternative to nerve autografts for the repair of peripheral nerve injuries and several commercially-available conduits are currently on the market. However, at present, utilization of these conduits is limited to the repair of nerve gaps less than 3 cm in length. Thus, current research is focused on how best to design artificial conduits with improved nerve regeneration potential over longer distances.

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Background: Surface properties of a biomaterial could be critical in determining biomaterial's biocompatibility due to the fact that the first interactions between the biological environment and artificial materials are most likely occurred at material's surface. In this study, the surface properties of a new nanocomposite (NC) polymeric material were modified by combining plasma treatment and collagen immobilization in order to enhance cell adhesion and growth.

Methods: NC films were plasma treated in reactive O2 plasma at 60 W for 120 s.

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In this study, central composite design (CCD) was used to develop predictive models to optimize operating conditions of plasma surface modification. It was concluded that out of the two process variables, power and duration of plasma exposure, the latter was significantly affecting the surface energy (γ(s) ), chemistry, and topography of polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane (POSS-PCU) films. On the basis of experimental data, CCD was used to model the γ(s) using a quadratic modeling of the process variables to achieve optimum surface energy to improve the interaction between endothelial cells (ECs).

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Ground-breaking advances in nanomedicine (defined as the application of nanotechnology in medicine) have proposed novel therapeutics and diagnostics, which can potentially revolutionize current medical practice. Polyhedral oligomeric silsesquioxane (POSS) with a distinctive nanocage structure consisting of an inner inorganic framework of silicon and oxygen atoms, and an outer shell of organic functional groups is one of the most promising nanomaterials for medical applications. Enhanced biocompatibility and physicochemical (material bulk and surface) properties have resulted in the development of a wide range of nanocomposite POSS copolymers for biomedical applications, such as the development of biomedical devices, tissue engineering scaffolds, drug delivery systems, dental applications, and biological sensors.

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Revolutionary advances in nanotechnology propose novel materials with superior properties for biomedical application. One of the most promising nanomaterials for biomedical application is polyhedral oligomeric silsesquioxane (POSS), an amazing nanocage consisting of an inner inorganic framework of silicon and oxygen atoms and an outer shell of organic groups. The unique properties of this nanoparticle has led to the development of a wide range of nanostructured copolymers with significantly enhanced properties including improved mechanical, chemical, and physical characteristics.

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Stent angioplasty is a successful treatment for arterial occlusion, particularly in coronary artery disease. The clinical communities were enthusiastic about the use of drug-eluting stents; however, these stents have a tendency to be a contributory factor towards late stage thrombosis, leading to mortality in a significant number of patients per year. This work presents an innovative approach in self-expanding coronary stents preparation.

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Hindlimb remote ischemic preconditioning (RIPC) reduces liver ischemia/reperfusion (IR) injury in wild-type mice. The underlying mechanisms of RIPC are currently unknown. In this study, we investigated the role of endothelial nitric oxide synthase (eNOS) in mediating the protective effects of RIPC.

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NO (nitric oxide) may protect the liver from IR (ischaemia/reperfusion) injury. RIPC (remote ischaemic preconditioning) also protects against liver IR injury; however, the molecular mediator(s) of RIPC are currently unknown. The aim of the present study was to assess the role of NO in hindlimb RIPC-induced protection against liver IR injury.

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Percutaneous transluminal coronary angioplasty revolutionized therapy for coronary artery disease. This early promise of a viable alternative to surgical treatment of coronary artery disease was thwarted by the high rates of angiographic restenosis. The advent of stenting reduced the rates of restenosis, although it was hindered by the new problem of in-stent restenosis.

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Conventionally used vascular grafts such as polyester (Dacron) or expanded polytetrafluoroethylene perform inadequately as small-diameter vascular bypass grafts (SDBGs). SDBGs, which can maintain long-term patency and those that could potentially evolve with the somatic growth, are highly desirable in vascular surgery and thus research into tissue-engineered blood vessels (TEBVs) is of keen interest. A TEBV was developed by seeding endothelial cells onto a collagen matrix that was cross-linked and contracted by smooth muscle cells (SMCs).

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Owing to their noninvasive nature, coronary artery stents have become popular demand for patients undergoing percutaneous coronary intervention. Late restenosis, in-stent restenosis, and late thrombosis, all mediated by the denuded endothelium, represent the most recurrent failures of vascular stent induction. Higher patency rates of stents can be achieved by restoring the native internal environment of the vessel-an endothelium monolayer.

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Background: The aim of this study was to manufacture a new aortic model with physiological properties, which could be used for long-term durability testing of endovascular stent-grafts, as per the recommendations of the Food and Drug Administration.

Methods: Porcine abdominal aortas were acquired to establish values for compliance. The aortic model was manufactured using a nanocomposite polymer.

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Colorectal cancer is the third most common cause of cancer-related deaths in the Western world. 5-Fluorouracil (5-FU) based chemotherapeutic regimes have been the mainstay of systemic treatment for disseminated colorectal cancer for many years. However, it only produces a 25% response rate due to the drug-resistance.

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