1,721,018 research outputs found
An introduction to ophthalmic biomaterials and their role in tissue engineering and regenerative medicine
No full textThis chapter presents a brief history of the development of ophthalmic biomaterials. Particularities in the development of ophthalmic biomaterials are discussed and some of their historic priorities within the general field of biomaterials are revealed or emphasized. The chapter then discusses the role and integration of ophthalmic biomaterials in tissue engineering and regenerative medicine applications
Reconstruction of the ocular surface using biomaterial templates
No full textThis chapter discusses the effect on vision of a large group of pathological conditions, known as ocular surface disorders (OSDs), and presents the therapeutic strategies to reconstruct the abnormal ocular surface. If left untreated, most of the OSDs will lead to partial or total loss of eyesight, especially when limbal stem cell deficiency is involved. An overview of\ud
various treatment strategies is presented, with the emphasis on the development of the ex vivo expansion of corneal limbal epithelial cells (presumed to be progenitor or stem cells) and the creation of transplantable epithelial constructs. The use of naturally derived biomaterials (collagen, fibrin, amnion, etc.) or synthetic polymers (polylactides, thermoresponsive\ud
polymers, etc.) as substrata in these constructs is critically analyzed. Emphasis is placed on the templates from silk proteins, which are being developed by the authors
Biomaterial templates for the culture and transplantation of retinal pigment epithelial cells: A critical review
No full textThe idea of retinal cell transplantation as a potential treatment for age-related retinal degeneration, a leading cause of blindness in the Western world, has been around for a number of decades. To date, however, it has not been entirely successful; one of the main reasons for this is the lack of an ideal substratum for the retinal cells, specifically for the growth of retinal pigment epithelial cells prior to transplantation. This chapter reviews the reasoning behind this potential treatment, the development of animal transplantation models for human trials, the prerequisites of an ideal substratum, the past and current research on substratum materials, and the potential for future developments in this area
Inherent risks associated with manufacture of bioengineered ocular surface tissue
No full textOBJECTIVE: To review the potential health risks associated with bioengineered ocular surface tissue, which serves as a bellwether for other tissues. METHODS: All clinical trials using bioengineered ocular surface tissue published between July 1, 1996, and June 30, 2005, were reviewed with respect to materials used and statements of risk assessment, risk remediation, adverse events, manufacturing standards, and regulatory oversight. RESULTS: Ninety-five percent of investigational protocols used 1 or more animal-derived products and an overlapping 95% used 1 or more donor human tissues. Consideration of risks reveals a very low probability of potential harm but a significant risk of disability or death if such an event were to occur. Details of ethics approval, patient consent, and donor serologic test results were not consistently provided. No references were made to risk assessment or to codes of manufacturing and clinical practice. CONCLUSION: While a degree of risk is associated with bioengineered ocular surface tissue, investigational reports of this new technology have yet to address issues of risk management and regulatory oversight. CLINICAL RELEVANCE: Attention to risk and codes of manufacturing and clinical practice will be required for advancement of the technology. We suggest the adoption of international standards to address these issues
Redefining and leading the academic discipline in Australian universities
No full textDisciplines have emerged as an alternative administrative structure to departments or schools in Australian universities. We presently investigate the pattern of discipline use and by way of case study examine a role for distributed leadership in discipline management. Over forty per cent of Australian universities currently employ disciplines, especially within faculties of sciences, engineering and medicine. No trend is observed according to institutional age, state, or historical origins. Effective planning, retention of corporate knowledge and good communication are important during the transition period. Moreover, it is vital that professional staff continue to work closely alongside academics as extended members of the discipline. Distributed leadership encourages this interaction. The duties of a discipline leader can be similar to those faced by a head of department. Universities should therefore establish clear policies, position descriptions and appropriate remuneration packages in order to recruit, train and retain staff within this emerging academic management role
Recent advances in the design of artificial corneas
Full text linkPURPOSE OF REVIEW: Artificial corneas are being developed to meet a shortage of donor corneas and to address cases in which allografting is contraindicated. A range of artificial corneas has been developed. Here we review several newer designs and especially those inspired by naturally occurring biomaterials found with the human body and elsewhere. RECENT FINDINGS: Recent trends in the development of artificial corneas indicate a move towards the use of materials derived from native sources including decellularized corneal tissue and tissue substitutes synthesized by corneal cells in vitro when grown either on their own or in conjunction with novel protein-based scaffolds. Biologically inspired materials are also being considered for implantation on their own with the view to promoting endogenous corneal tissue. SUMMARY: More recent attempts at making artificial corneas have taken a more nature-based or nature-inspired approach. Several will in the near future be likely to be available clinically
A school by any other name...is still a rock band?
No full textHow is your academic institution structured? If you work within a university, then no doubt you are familiar with the use of faculties or perhaps colleges. What about departments or schools? Whatever names or structures are employed, how would you describe the working relationship between academics and professional staff members?\ud
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As a research scientist and academic over the last twenty years, my appointments have almost always been made through academic departments or schools. In each case, the academic unit has been led by a senior academic manager, such as a chair or head, supported by a dedicated team of professional staff. More recently, however, I have had the opportunity of leading an academic discipline and the experience has led me to reflect more broadly about leadership styles and academic structures within the Australian higher education sector. The written record of this reflection was published last year in the Australian Universities Review (Harkin and Healy, 2013), but I’m pleased to be able to provide a brief synopsis here for the readership of Insights
Biomaterials and Regenerative Medicine in Ophthalmology [2nd Edition]
No full text"Biomaterials and Regenerative Medicine in Ophthalmology, Second Edition, focuses on an aging population and the increasing instances of eye diseases. Biomaterials continue to be used for numerous medical devices for the restoration of eyesight, improving many patients’ quality of life. Consequently, biomaterials and regenerative medicine are becoming increasingly important to the advances of ophthalmology and optometry. This book provides readers with an updated and expanded look at the present status and future direction of biomaterials and regenerative medicine in this important field."--Publisher websit
Responses of keratinocytes to substrate-bound vitronectin: Growth factor complexes
No full textInsulin-like growth factor-1 (IGF-I) can associate with the extracellular matrix protein vitronectin (VN) via select IGF-binding proteins, and the resulting complex stimulates responses in a variety of cell types. As VN can also associate with epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF), we hypothesized that the multimeric nature of VN could be exploited to deliver multiple growth factors to the cell surface. We report here that VN enhances bFGF but not EGF stimulated [(3)H]-leucine incorporation in the HaCAT keratinocyte cell line, with VN synergistically enhancing cell migration in response to both EGF and bFGF when presented as a VN-bound complex. Furthermore, the addition of EGF and/or bFGF to IGF-I:IGFBP-5:VN complexes significantly enhances both [(3)H]-leucine incorporation and migration of HaCAT cells above that induced by IGF:IGFBP-5:VN complexes alone. Indeed, similar responses are observed in primary cultures of human skin keratinocytes, highlighting the potential use of these novel complexes for a wide range of tissue repair applications
Development of an ultra-thin fibroin membrane for RPE cell transplantation
No full text<b>Purpose</b>\ud
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- One of the challenges associated with cell-based therapies for repairing the retina is the development of suitable materials on which to grow and transplant retinal cells. Using the ARPE-19 cell line, we have previously demonstrated the feasibility of growing RPE-derived cells on membranes prepared from the silk protein fibroin. The present study was aimed at developing a porous, ultra-thin fibroin membrane that might better support development of apical-basal polarity in culture, and to extend this work to primary cultures of human RPE cells. \ud
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<b>Methods</b>\ud
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- Ultra-thin fibroin membranes were prepared using a highly polished casting table coated with Topas® (a cyclic olefin copolymer) and a 1:0.03 aqueous solution of fibroin and PEO (M<sub>v</sub> 900 000 g/mol). Following drying, the membranes were water annealed to make them water-stable, washed in water to remove PEO, sterilised by treatment with 95% ethanol, and washed extensively in saline. Primary cultures containing human RPE cells were established from donor posterior eye cups and maintained in DMEM/F12 medium supplemented with 10% fetal bovine serum and antibiotics. First passage cultures were seeded onto fibroin membranes pre-coated with vitronectin and grown for 6 weeks in medium supplemented with 1% serum. Comparative cultures were established on porous 1.0 µm pore PET membrane (Millipore) and using ARPE-19 cells. \ud
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<b>Results</b>\ud
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- The fibroin membranes displayed an average thickness of 3 µm and contained numerous dimples/pore-like structures of up to 3-5 µm in diameter. The primary cultures predominantly contained pigmented epithelial cells, but mesenchymal cells (presumed fibroblasts) were also often present. Passaged cultures appeared to attach equally well to either fibroin or PET membranes. Over time cells on either material adopted a more cobblestoned morphology.\ud
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<b>Conclusions:</b>\ud
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- Progress has been made towards developing a porous ultra-thin fibroin membrane that supports cultivation of RPE cells. Further studies are required to determine the degree of membrane permeability and RPE polarity
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