141 resultados para Smart biomaterials, Clinical translation, Medical devices and implants, Tissue engineering, Orthopedic surgery, Plastic surgery-extracellular matrix


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Advances in medical science have presented both law and bioethics with some of the most fascinating questions of our time. As science continues to forge ahead into new frontiers, in fields such as reproductive technology, human genetics, cloning technologies, and stem cell research, questions have arisen over the role for law in regulating this new terrain. The speed with which medical science has advanced, and continues to advance, can make it difficult to formulate appropriate regulatory responses. The rapid pace of scientific change and the increasing complexity of the science can present hurdles and barriers to the engagement of the public with science and the legal and ethical issues raised by it.

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The articles collected here in this special edition Epithelial-Mesenchymal (EMT) and Mesenchymal-Epithelial Transitions (MET) in Cancer provide a snapshot of the very rapidly progressing cinemascope of the involvement of these transitions in carcinoma progression. Pubmed analysis of EMT and cancer shows an exponential increase in the last few years in the number of papers and reviews published under these terms (Fig. 1). The last few years have seen these articles appearing in high calibre journals including Nature, Nature Cell Biology, Cancer Cell, PNAS, JNCI, JCI, and Cell, signaling the acceptance and quality of work in this field.

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We initially described a rat chamber model with an inserted arteriovenous pedicle which spontaneously generates 3-dimensional vascularized connective tissue (Tanaka Y et al., Br J Plast Surg 2000; 53: 51-7). More recently we have developed a murine chamber model containing reconstituted basement membrane (Matrigel®) and FGF-2 that generates vascularized adipose tissue in vivo (Cronin K et al., Plast Reconstr Surg 2004; in press). We have extended this work to assess the cellular and matrix requirements for the Matrigel®- induced neo-adipogenesis. We found that chambers sealed to host fat were unable to grow new adipose tissue. In these chambers the Matrigel® became vascularized with maximal outgrowth of vessels extending to the periphery at 6 weeks. A small amount of adipose tissue was found adjacent to the vessels, most likely arising from periadventitial adipose tissue. In contrast, chambers open to interaction with endogenous adipose tissue showed abundant new fat, and partial exposure to adjacent adipose tissue clearly showed neo-adipogenesis only in this area. Addition of small amounts of free fat to the closed chamber containing Matrigel® was able to induce neo-adipogenesis. Addition of small pieces of human fat also caused neo-adipogenesis in immunocompromised (SCID) mice. Also, we found Matrigel® to induce adipogenesis of Lac-Z-tagged (Rosa-26) murine bone marrow-derived mesenchymal stem cells, and cells similar to these have been isolated from human adipose tissue. Given that Matrigel® is a mouse product and cannot be used in humans, we have started investigating alternative matrix scaffolds for adipogenesis such as the PDA-approved PLGA, collagen and purified components derived from Matrigel®, such as laminin-1. The optimal conditions for adipogenesis with these matrices are still being elucidated. In conclusion, we have demonstrated that a precursor cell source inside the chamber is essential for the generation of vascularized adipose tissue in vivo. This technique offers unique potential for the reconstruction of soft tissue defects and may enable the generation of site-specific tissue using the correct microenvironment.

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This article describes the first steps toward comprehensive characterization of molecular transport within scaffolds for tissue engineering. The scaffolds were fabricated using a novel melt electrospinning technique capable of constructing 3D lattices of layered polymer fibers with well - defined internal microarchitectures. The general morphology and structure order was then determined using T 2 - weighted magnetic resonance imaging and X - ray microcomputed tomography. Diffusion tensor microimaging was used to measure the time - dependent diffusivity and diffusion anisotropy within the scaffolds. The measured diffusion tensors were anisotropic and consistent with the cross - hatched geometry of the scaffolds: diffusion was least restricted in the direction perpendicular to the fiber layers. The results demonstrate that the cross - hatched scaffold structure preferentially promotes molecular transport vertically through the layers ( z - axis), with more restricted diffusion in the directions of the fiber layers ( x – y plane). Diffusivity in the x – y plane was observed to be invariant to the fiber thickness. The characteristic pore size of the fiber scaffolds can be probed by sampling the diffusion tensor at multiple diffusion times. Prospective application of diffusion tensor imaging for the real - time monitoring of tissue maturation and nutrient transport pathways within tissue engineering scaffolds is discussed.

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Background: Cancer metastasis is the main contributor to breast cancer fatalities as women with the metastatic disease have poorer survival outcomes than women with localised breast cancers. There is an urgent need to develop appropriate prognostic methods to stratify patients based on the propensities of their cancers to metastasise. The insulin-like growth factor (IGF)-I:IGF binding protein (IGFBP):vitronectin complexes have been shown to stimulate changes in gene expression favouring increased breast cancer cell survival and a migratory phenotype. We therefore investigated the prognostic potential of these IGF- and extracellular matrix (ECM) interaction-induced proteins in the early identification of breast cancers with a propensity to metastasise using patient-derived tissue microarrays. Methods: Semiquantitative immunohistochemistry analyses were performed to compare the extracellular and subcellular distribution of IGF- and ECM-induced signalling proteins among matched normal, primary cancer and metastatic cancer formalin-fixed paraffin-embedded breast tissue samples. Results: The IGF- and ECM-induced signalling proteins were differentially expressed between subcellular and extracellular localisations. Vitronectin and IGFBP-5 immunoreactivity was lower while β1 integrin immunoreactivity was higher in the stroma surrounding metastatic cancer tissues, as compared to normal breast and primary cancer stromal tissues. Similarly, immunoreactive stratifin was found to be increased in the stroma of primary as well as metastatic breast tissues. Immunoreactive fibronectin and β1 integrin was found to be highly expressed at the leading edge of tumours. Based on the immunoreactivity it was apparent that the cell signalling proteins AKT1 and ERK1/2 shuffled from the nucleus to the cytoplasm with tumour progression. Conclusion: This is the first in-depth, compartmentalised analysis of the distribution of IGF- and ECM-induced signalling proteins in metastatic breast cancers. This study has provided insights into the changing pattern of cellular localisation and expression of IGF- and ECM-induced signalling proteins in different stages of breast cancer. The differential distribution of these biomarkers could provide important prognostic and predictive indicators that may assist the clinical management of breast disease, namely in the early identification of cancers with a propensity to metastasise, and/or recur following adjuvant therapy.

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Female genital cutting (also often called female genital mutilation, or female circumcision) is a cultural practice that originated thousands of years ago. Female genital cutting has various forms, some of which are more invasive than others, but all of which produce health, legal and social consequences for those involved. Due to patterns of immigration in Australia, especially since the 1990s, there are women in Australia who have experienced female genital cutting. There may be some families, or some parents, who still hold a cultural commitment to female genital cutting. As a result, female genital cutting presents complex legal, ethical, medical and social challenges in contemporary Australian society. Medical practitioners and other health and welfare workers may encounter women who have experienced genital cutting and who require treatment for its sequelae. Currently, legislative frameworks for female genital cutting vary across states and territories, including the penalties for conducting it, and for removing a child for the purpose of conducting it outside Australia. This presentation provides an overview of the history, nature and consequences of the various forms of female genital cutting, and of the major Australian legal principles, ethical controversies, and medical, legal and social challenges in this field.

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Infective endocarditis (IE) is a life-threatening infection of the heart endothelium and valves. Staphylococcus aureus is a predominant cause of severe IE and is frequently associated with infections in health care settings and device-related infections. Multilocus sequence typing (MLST), spa typing, and virulence gene microarrays are frequently used to classify S. aureus clinical isolates. This study examined the utility of these typing tools to investigate S. aureus epidemiology associated with IE. Ninety-seven S. aureus isolates were collected from patients diagnosed with (i) IE, (ii) bloodstream infection related to medical devices, (iii) bloodstream infection not related to medical devices, and (iv) skin or soft-tissue infections. The MLST clonal complex (CC) for each isolate was determined and compared to the CCs of members of the S. aureus population by eBURST analysis. The spa type of all isolates was also determined. A null model was used to determine correlations of IE with CC and spa type. DNA microarray analysis was performed, and a permutational analysis of multivariate variance (PERMANOVA) and principal coordinates analysis were conducted to identify genotypic differences between IE and non-IE strains. CC12, CC20, and spa type t160 were significantly associated with IE S. aureus. A subset of virulence-associated genes and alleles, including genes encoding staphylococcal superantigen-like proteins, fibrinogen-binding protein, and a leukocidin subunit, also significantly correlated with IE isolates. MLST, spa typing, and microarray analysis are promising tools for monitoring S. aureus epidemiology associated with IE. Further research to determine a role for the S. aureus IE-associated virulence genes identified in this study is warranted.

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It is argued that the smart cities model promise solutions to fuel sustainable development and a high quality of life with a wise management of natural resources, through participatory action and engagement. The paper provides a critical review of this model and application attempts of smart urban technologies in contemporary cities by particularly looking into emerging practices of ubiquitous eco-cities as exemplar smart cities initiatives. Through a thorough review of literature and best practices on the smart cities model, this paper attempts to address the research question of whether smart cities model is just another fashionable city brand or an effective urban development and management model to solve the problems of our cities. The findings shed light on urban planning and development considerations for the integration of smart urban technologies and their possible implications in shaping up of the built environment to produce prosperous and sustainable urban futures.

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Predictors of people’s intention to register with a body bequest program for donating their deceased body to medical science and research were examined using standard theory of planned behavior (TPB) predictors (attitude, subjective norm, perceived behavioral control) and adding moral norm, altruism, and knowledge. Australian students (N = 221) at a university with a recently established body bequest program completed measures of the TPB’s underlying beliefs (behavioral, normative, and control beliefs) and standard and extended TPB predictors, with a sub-sample reporting their registration-related behavior 2 months later. The standard TPB accounted for 43.6%, and the extended predictors an additional 15.1% of variance in intention. The significant predictors were attitude, subjective norm, and moral norm, partially supporting an extended TPB in understanding people’s body donation intentions. Further, important underlying beliefs can inform strategies to target prospective donors.

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In various embodiments, optoelectronic devices are described herein. The optoelectronic device may include an optoelectronic cell arranged so as to wrap around a central axis wherein the cell includes a first conductive layer, a semi-conductive layer disposed over and in electrical communication with the first conductive layer, and a second conductive layer disposed over and in electrical communication with the semi-conductive layer. In various embodiments, methods for making optoelectronic devices are described herein. The methods may include forming an optoelectronic cell while flat and wrapping the optoelectronic cell around a central axis. The optoelectronic devices may be photovoltaic devices. Alternatively, the optoelectronic devices may be organic light emitting diodes.

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Christmas is usually a time for celebration, being with family and friends, opening presents, stuffing yourself silly with food at Christmas lunch – then doing it all over again at dinner. However, this may not be the case for some people. Relationships with family may be strained, or there may have been the loss of a loved one or significant other...

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Inflammatory bowel disease (IBD) describes a group of chronic relapsing inflammatory conditions of the gastrointestinal tract (GIT), with Crohn’s disease and ulcerative colitis being the two most common. Ulcerative colitis affects the colon, with the inflammation limited to the colonic mucosal layers. In contrast, the full thickness of the gut wall can be inflamed in Crohn’s disease, and any part of the GIT can be affected – from the mouth to the anus, though the small and large intestine are most commonly involved...

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The effects of different exercise intensities on health have been investigated in several studies in recent years, in which some authors showed greater benefits for vigorous exercise (6) while others did not find any differences (8). An important issue regarding these conflicting results could be the fact that only a few of the studies controlled the effects of different exercise intensities for the overall volume of physical activity, making the evaluation of the available data difficult.

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This 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.

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Despite positive testing in animal studies, more than 80% of novel drug candidates fail to proof their efficacy when tested in humans. This is primarily due to the use of preclinical models that are not able to recapitulate the physiological or pathological processes in humans. Hence, one of the key challenges in the field of translational medicine is to “make the model organism mouse more human.” To get answers to questions that would be prognostic of outcomes in human medicine, the mouse's genome can be altered in order to create a more permissive host that allows the engraftment of human cell systems. It has been shown in the past that these strategies can improve our understanding of tumor immunology. However, the translational benefits of these platforms have still to be proven. In the 21st century, several research groups and consortia around the world take up the challenge to improve our understanding of how to humanize the animal's genetic code, its cells and, based on tissue engineering principles, its extracellular microenvironment, its tissues, or entire organs with the ultimate goal to foster the translation of new therapeutic strategies from bench to bedside. This article provides an overview of the state of the art of humanized models of tumor immunology and highlights future developments in the field such as the application of tissue engineering and regenerative medicine strategies to further enhance humanized murine model systems.