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1
Moreau, Jodie E. "Stimulation of bone marrow stromal cells in the development of tissue engineered ligaments /". Thesis, Connect to Dissertations & Theses @ Tufts University, 2005.
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Thesis (Ph.D.)--Tufts University, 2005.Adviser: Gregory H. Altman. Submitted to the Dept. of Biology--Biotechnology. Includes bibliographical references (leaves 183-192). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
2
Halse, Tore Egil, e Thomas Tøkje. "Tissue". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18790.
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In this thesis, the development of a web application for designing electronic circuits has been initiated and documented.The application will feature some unique features regarding the design process of electronic circuits.Among them are interface based routing, a plugin-friendly environment and a collaborative resource database.At the start of working on this thesis, there were no known web-based EDA software available.This provided an unique opportunity to fill this gap.The application has been implemented using HTML5 and JavaScript for the interactive front-end (The web browser),and Google Go and MongoDB for the backend (The Server).The basic building blocks of this application has been implemented, and together serves as an tech demo, available under a GPL licence.
3
Shazly, Tarek (Tarek Michael). "Tissue-material interactions : bioadhesion and tissue response". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54577.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 159-162).
Diverse interactions between soft tissues and implanted biomaterials directly influence the success or failure of therapeutic interventions. The nature and extent of these interactions strongly depend on both the tissue and material in question and can presumably be characterized for any given clinical application. Nevertheless, optimizing biomaterial performance remains a challenge in many implant scenarios due to complex relationships between intrinsic material properties and tissue response. Soft tissue sealants are clinically-relevant biomaterials which impart therapeutic benefit through adhesion to tissue, thus exhibiting a direct functional dependence on tissue-material reactivity. Because adhesion can be rigorously quantified and correlated to the local tissue response, sealants provide an informative platform for studying material properties, soft tissues, and their interplay. We developed a model hydrogel sealant composed of aminated polyethylene glycol and dextran aldehyde (PEG:dextran) that can possess a wide range of bulk and adhesive properties by virtue of constituent polymer modifications. Through comparison to traditional sealants, we established that highly viscoelastic adhesion promotes tissue-sealant interfacial failure resistance without compromising underlying tissue morphology.
(cont.) We analyzed multiple soft tissues to substantiate the notion that natural biochemical variability facilitates the design of tissue-specific sealants which have distinct advantages over more general alternatives. We confirmed that hydrogel-based materials are an attractive material class for ensuring sealant biocompatibility, but found that a marked reduction in adhesive strength following characteristic swell can potentially limit clinical efficacy. To mitigate the swell-induced loss of hydrogel-based sealant functionality, a biomimetic conjugation strategy derived from marine mussel adhesion was applied to PEG:dextran and shown to favorably modulate adhesion. In all phases of this research, we defined material design principles that extend beyond the immediate development of PEG:dextran with potential to enhance the clinical performance of a range of biomaterials.
by Tarek Shazly.
Ph.D.
4
Tam, Y. Y. A. "Connective tissue growth factor in tissue fibrosis". Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1448702/.
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Systemic Sclerosis (SSc) is a connective tissue disease characterised by inflammation and autoimmunity, vasculopathy, and interstitial remodelling and fibrosis. This thesis focuses on CTGF (CCN2), a member of the CCN family of matricellular proteins, as elevated CTGF expression is a hallmark of chronic fibrotic diseases such as SSc. In addition to the association of CTGF expression and fibrosis in human disease, experimentally, fibroblast-specific overexpression of CTGF has been shown to induce a fibrotic phenotype, as demonstrated in the Col1a2-CTGF transgenic mice. Prominent features of fibrosis included a thickened dermis, as well as excess collagen deposition in the skin and lung. This CTGF overexpression also provoked changes in the alveolar epithelium. In the lung of Col1a2-CTGF mice, immunostaining revealed a marked increase in the number of cells co-expressing the epithelial marker, TTF-1 and mesenchymal cell markers α-SMA and Snai1, indicative of epithelial-to-mesenchymal transition (EMT)-like changes. This suggested a role for the paracrine effects of CTGF in promoting the phenotypic switching of alveolar epithelial cells. EMT is likely to contribute, at least in part, to the accumulation of interstitial fibroblasts during fibrosis. Complementary in vitro studies in alveolar epithelial cells (AECs) showed that CTGF knockdown using siRNA suppressed TGF-β-induced mesenchymal cell proteins while inducing redistribution of the epithelial cell marker E-cadherin. Immunostaining and Western blotting showed that recombinant CTGF induced EMT-like morphological changes and expression of α-SMA in AECs. Finally, we were interested in whether the reduction or absence of CTGF could abrogate fibrosis. Knockdown of CTGF suppressed the induction of fibrotic proteins in TGF-β-treated control fibroblasts and SSc lung fibroblasts. Deletion of the CTGF gene showed reduced bleomycin-induced pulmonary fibrosis in mice. Overall, these results support that CTGF plays a pivotal role in fibrosis and blocking CTGF activity may be useful as a specific target of attenuating fibrosis in SSc.
5
Lipworth, Wendy. "Reconfiguring tissue banking consent through enrichment of a restricted debate". Connect to full text, 2005. http://hdl.handle.net/2123/683.
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Thesis (M. Sc.)--University of Sydney, 2005.Title from title screen (viewed 21 May 2008). Submitted in fulfilment of the requirements for the degree of Master of Science to the Unit for the History and Philosophy of Science and Centre for Values, Ethics and Law in Medicine. Includes bibliographical references. Also available in print form.
6
Deiuliis, Jeffrey Alan. "The metabolic and molecular regulation of adipose triglyceride lipase". Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1185546165.
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7
Le, Thua Trung Hau. "Multimodality Treatment of Soft Tissue and Bone Defect: from Tissue Transfer to Tissue Engineering". Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/220961.
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In the first part of these studies, we have performed standard microsurgical procedures provide a solution for long standing bone and soft tissue defects, even in cases of longstanding osteomyelitis of long bones. When long bony segments are missing, the microvascular bone transfer provides a reliable method. In smaller soft tissue and bone defects, the application of a descending genicular osteomyocutaneous flap provides an option with low donor site morbidity. In the second part, we have focussed on reducing the donor site morbidity and expanded on the application of tissue engineering methods. MSCs derived from bone marrow can be injected percutaneous or be combined with an autologous bony scaffold for treatment of delayed union and nonunion. The outcome of our studies, however, limited in number of patients, clearly showed the possibilities and advantages of this new approach. A multimodality approach is essential, but it can provide promising solutions. Well-established microvascular and modern biotechnology methods will improve patient satisfaction and functional recovery in severe limb trauma, often the result of high-energy motorcycle accidents.Doctorat en Sciences médicales (Médecine)
info:eu-repo/semantics/nonPublished
8
Cristea, Anca. "Ultrasound tissue characterization using speckle statistics". Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10329.
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L'objectif de la caractérisation des tissus par ultrasons ou ‘Quantitative Ultrasound (QUS)’ est de différencier les tissus pathologiques en associant les paramètres d’un modèle aux caractéristiques physiques du tissu. L'usage exclusif des ultrasons pour obtenir un diagnostic peut garantir que le patient ne subira pas une procédure invasive (e.g. une biopsie), utilisant des rayonnements ionisants (e.g. la tomographie) ou même inconfortable et coûteuse (e.g. IRM). Les méthodes de QUS extraient des informations sur la microstructure du tissu à partir du contenu spectral ou temporel des signaux ultrasonores. Le signal temporel radiofréquence (RF) et son enveloppe sont d'intérêt à cause du speckle crée par l’interférence des ondes, qui peut être modélisé par des distributions statistiques. Ce travail propose d'explorer la possibilité d'obtenir des estimations QUS fiables en utilisant des distributions statistiques comme modèles pour le speckle ultrasonore. Les estimations sont constituées des paramètres des distributions respectives et dépendent de la densité de diffuseurs dans le milieu. L’évaluation s’effectue sur des images simulées, des fantômes de particules et des biofantômes. Dans la première partie, la distribution Gaussienne Généralisée est utilisée pour modéliser le signal RF, et la distribution de Nakagami est utilisée pour modéliser son enveloppe. Les deux distributions sont limitées à discriminer les milieux avec une faible densité de diffuseurs, parce que les valeurs de leurs paramètres de forme saturent pour un speckle pleinement développé. Par conséquent, puisque la formation du speckle pleinement développé dépend de la résolution du système d'imagerie, la caractérisation peut se faire seulement à de très hautes résolutions, correspondant à des hautes fréquences qui ne sont pas communes en échographie clinique. Une application du modèle de Nakagami sur l’image crée par la seconde harmonique montre le potentiel du paramètre de forme de Nakagami en tant que mesure de la nonlinéarité du milieu. Dans la deuxième partie, l'enveloppe a été modélisée en utilisant la distribution K-Homodyne. Le paramètre de regroupement des diffuseurs α permet de discriminer entre les milieux denses jusqu’à une limite supérieure à celle du paramètre de Nakagami. Pourtant, cette limite est difficile à estimer avec précision, parce que les valeurs caractéristiques pour le speckle pleinement développé sont affectées par un biais et une variance élevés. Le biais et la variance peuvent être améliorés en augmentant la quantité de données utilisée pour l’estimation. Dans la dernière partie, une technique de déconvolution spécialement conçue pour la caractérisation des tissus a été évaluée. Des essais exhaustifs ont montré qu’elle n’est pas suffisamment robuste pour une application clinique, puisque les images déconvoluées ne sont pas fidèles à la réflectivité originale du milieuThe purpose of ultrasound tissue characterization or Quantitative Ultrasound (QUS) is to differentiate between tissue pathologies by associating model parameters to physical tissue features. The exclusive use of ultrasound for diagnosis would guarantee that the patient does not undergo a procedure that is invasive (e.g. a biopsy), using ionizing radiation (e.g. tomography) or simply uncomfortable and expensive (e.g. MRI). QUS methods extract information on the tissue microstructure from the temporal or spectral content of the acquired ultrasound signals. The temporal radiofrequency (RF) signal and its envelope are of interest because of the speckle patterns created by wave interference, which can be modeled by statistical distributions. The present work proposes to explore the possibility of obtaining reliable QUS estimates by using statistical distributions as models for ultrasound speckle. The estimates consist in the parameters of the respective distributions and are indicators of the scatterer density in the medium. The evaluation is conducted on simulated images, particle phantoms and biophantoms. In the first part, the Generalized Gaussian distribution is used to model the RF signal, and the Nakagami distribution is used to model its envelope. The two distributions show limitations in discriminating media with high scatterer densities, as the values of their shape parameters saturate in the fully developed speckle regime. Therefore, since the formation of fully developed speckle depends on the resolution of the imaging system, characterization can be done only at very high resolutions, corresponding to high frequencies that are not common in clinical ultrasound. An application of the Nakagami model on the second harmonic image shows the potential of the Nakagami shape parameter as a measure of the nonlinearity of the medium. In the second part, the echo envelope was modeled using the Homodyned-K distribution. The scatterer clustering parameter α allows the discrimination of dense media up to a concentration that is higher than the one that limits the Nakagami distribution. However, this limit is difficult to estimate precisely, because the values of α that are characteristic for fully developed speckle suffer from large estimation bias and variance. The bias and the variance can be improved by performing the estimation on a very large amount of data. In the final part, a deconvolution technique designed specifically for ultrasound tissue characterization has been analyzed. Extensive testing has shown it to not be sufficiently robust for clinical applications, since the deconvolved images are not reliable in terms of fidelity to the original reflectivity of the medium
9
Craddock, Russell. "Structural characterisation of aggrecan in cartilaginous tissues and tissue engineered constructs". Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/structural-characterisation-of-aggrecan-in-cartilaginous-tissues-and-tissue-engineered-constructs(d1e72d1e-b0ac-4485-9a05-030a5faf8351).html.
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Collagen II and the proteoglycan aggrecan are key extracellular matrix (ECM) proteins in cartilaginous tissues such as the intervertebral disc (IVD). Given the functional role that these structural and functional proteins have in the IVD, ECM in tissue engineered intervertebral disc (TE IVD) constructs needs to recapitulate native tissue. As such, there is a need to understand the structure and mechanical function of these molecules in native tissue to inform TE strategies. The aims here were to characterise aggrecan and collagen II using atomic force microscopy (AFM), size-exclusion chromatography multi angle light scattering (SEC-MALS), histology, quantitative PCR, nanomechanical and computational modelling in: (i) skeletally immature and mature bovine articular cartilage (AC) and nucleus pulposus (NP), (ii) TE IVD constructs cultured in hypoxia or treated with transforming growth factor beta [TGFÎ23] or growth differentiation factor [GDF6]), and (iii) porcine AC and NP tissue. No variation in collagen II structure was observed although the proportion of organised fibrillar collagen varied between tissues. Both intact (containing all three globular domains) and non-intact (fragmented) aggrecan monomers were isolated from both AC and IVD and TE IVD constructs. Mature intact native NP aggrecan was ~60 nm shorter (core protein length) compared to AC. In skeletally mature bovine NP and AC tissue, most aggrecan monomers were fragmented (99% and 95%, respectively) with fragments smaller and more structurally heterogeneous in NP. Similar fragmentation was observed in skeletally immature bovine AC (99.5%), indicating fragmentation occurs developmentally at an early age. Fragmentation was not a result of enhanced gelatinase activity. Aggrecan monomers isolated from notochordal cell rich porcine NP were also highly fragmented, similar to bovine NP. Application of a computational packing model suggested fragmentation may affect porosity and nutrient transfer. The reduced modulus was greater in AC than NP (497 kPa and 76.7 kPa, respectively) with the difference likely due to the organisation and abundance of ECM molecules, rather than individual structure. Growth factors (GDF6 and TGFÎ23), and not oxygen tension treated TE IVD constructs were structurally (with >95% fragmented monomers), histologically and mechanically (GDF6: 60.2 kPa; TGFÎ23; 69.9 kPa) similar to native NP tissue (76.7 kPa) and there was evidence of gelatinase activity. To conclude, these results show that the ultrastructure of intact aggrecan was tissue and cell dependent, and could be modified by manipulation of cell culture conditions, specifically GDF6 which may play a role in aggrecan glycosylation.
10
Dean, Drew W. Kane Robert R. "Meniscal tissue bonding and exploration of sonochemical tissue modification". Waco, Tex. : Baylor University, 2008. http://hdl.handle.net/2104/5291.
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Bouget, Gwenaëlle. "Implication de la petite GTPase Rab4b des lymphocytes T dans les complications métaboliques de l’obésité". Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4050/document.
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Lors de l’obésité, les défauts d’expansion du tissu adipeux blanc sont à l’origine des désordres métaboliques. Lorsque les adipocytes atteignent leurs capacités maximales de stockage de triglycérides, des dépôts ectopiques de lipides apparaissent dans le foie et le muscle conduisant à la résistance à l’insuline. De plus, les adipocytes dysfonctionnels sécrètent des facteurs d’alertes établissant une inflammation dans le tissu adipeux. Cette inflammation est médiée par les communications entre les adipocytes et les cellules immunitaires qui sont contrôlées par l’endocytose et le trafic intracellulaire. L’endocytose et les protéines Rab gouvernant ce processus pourraient être des éléments clés de l’expansion du tissu adipeux. L’équipe a démontré que l’expression de Rab4b était diminuée dans le tissu adipeux de patients obèses diabétiques et de souris obèses. Nos travaux montrent que l’expression de Rab4b est diminuée dans les lymphocytes T du tissu adipeux de souris et de patients obèses. L’invalidation de Rab4b dans les lymphocytes T in vivo induit une résistance à l’insuline et une accumulation d’acides gras dans le foie et dans le muscle sous régime normal. Ces défauts sont dus à une inhibition de l’adipogenèse par l’IL-6 et l’IL-17, limitant l’expansion du tissu adipeux. L’augmentation de ces cytokines pro-inflammatoires est une conséquence de l’augmentation du nombre de lymphocytes Th17 et une diminution des lymphocytes T régulateurs. Nous décrivons un nouveau mécanisme par lequel l’expression de Rab4b dans les lymphocytes T régule les complications métaboliques de l’obésité en changeant les sous-populations de cellules immunitaires dans le tissu adipeuxExpendability defect of adipose tissue during obesity is at the basis of obesity-related metabolic complications. Indeed, when adipocytes reach their maximal triglyceride storage capacity, ectopic lipid depots are appearing in liver and muscles, leading to insulin resistance. Moreover, dysfunctional adipocytes secrete alarming factors leading to adipose tissue inflammation. This inflammation is sustained by adipocytes and immune cells communications that are controlled by endocytosis and intracellular trafficking. Endocytosis and its governing proteins, the Rab GTPases, could be pivotal in the regulation of adipose tissue expandability. Our team has demonstrated that Rab4b expression is reduced in obese diabetic patients and mice adipose tissues. The present work demonstrates that Rab4b is decreased in adipose tissue T cells in both obese patient and mice. The depletion of Rab4b in T cells in vivo leads to insulin resistance and lipid accumulation in liver and muscles under normal diet. These defects are due to adipogenesis inhibition by IL-6 and IL-17, which limits adipose tissue expansion. These pro-inflammatory cytokines are increased in adipose tissue of the mice depleted for Rab4b in T cells because the number of Th17 is increased at the expense of the number of regulatory T cells. We describe here a new mechanism in which Rab4b expression in T cells control obesity-related metabolic complications by tuning T cells subpopulations in adipose tissue
12
Ghezzi, Chiara Elia. "Dense collagen-based tubular tissue constructs for airway tissue engineering". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114489.
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To date, only engineered tissues of planar geometry, such as epidermal and dermal layer substitutes, have successfully reached the market, mainly due to their relative low complexity and simple geometry. In contrast, the mechanical and functional requirements of tubular tissues are more stringent compared to planar tissues. Tubular tissues, which are the main components of several biological systems (e.g. circulatory, urinary or respiratory), not only present an increased complexity in geometry and tissue architecture, they are also populated by mixed cell types. In addition, these are continuously exposed to cyclic mechanical stimuli, which modulate cellular responses and ultimately the functionality of the tissues. Therefore, the understanding and the ability to reproduce physiologically equivalent environments are critical to generate mechanically and biologically functional neo-tissues or tissue models. The aim of this doctoral research was to produce and characterize 3D DC-based tubular constructs as tissue models for airway tissue engineering in physiologically relevant culture conditions. The first objective was to develop DC-based constructs and evaluate, in real-time, the responses of seeded fibroblasts to PC and to culturing with the DC environment; the fabrication and characterization of mesenchymal stem cell (MSC) seeded multilayered DC-SF-DC hybrids; and to evaluate the differentiation of MSCs cultured within multilayered DC-SF-DC hybrids.The second objective was to develop and characterize cell-seeded tubular dense collagen constructs (TDCCs) with bioinspired mechanical properties.The third objective was to implement tubular dense collagen-based constructs as an airway tissue model through the evaluation of airway smooth muscle cell (ASMC) responses within TDCC under physiological mechanical stimuli, and the development of a multilayered tubular dense collagen-silk fibroin construct (TDC-SFC) that mimicked airway tract architecture in order to study MSC responses under physiological mechanical stimulation.By providing ASMCs with a physiologically equivalent niche, and through pulsatile flow stimulation, in vitro, ASMCs exhibited their native orientation, maintained their contractile phenotype and enhanced the mechanical properties of the TDCC through matrix remodelling. The ability of TDC-SFC to transfer physiological pulsatile stimulation to resident MSCs resulted in native-like cell orientation (i.e. parallel to circumferential strain), and induced MSC contractile phenotype expression.In conclusion, the tubular dense collagen-based constructs developed and implemented, in this doctoral dissertation, effectively provided an in vitro airway tissue model for potential preclinical studies to mimic physiological and pathological conditions (e.g. inflammatory and degenerative diseases) in a relevant biomechanical environment, as alternatives to simple tissue culture techniques or complex animal models.À ce jour, seuls les tissus synthétisés de forme plane, comme les substituts dermiques et épidermiques, ont réussi à percer le marché, surtout en raison de leur complexité relativement faible et de leur géométrie simple. À l'opposé, les exigences mécaniques et fonctionnelles des tissus tubulaires imposent un plus grand nombre de contraintes que les tissus planaires. Principales composantes de plusieurs systèmes biologiques (circulatoire, urinaire ou respiratoire), les tissus tubulaires sont non seulement plus complexes sur le plan de la géométrie et de l'architecture tissulaire, mais ils sont aussi composés de cellules de différents types. De plus, ils sont continuellement exposés à des stimuli mécaniques cycliques. Voilà pourquoi il est essentiel de comprendre les milieux physiologiquement équivalents et de pouvoir les reproduire si on veut obtenir des néotissus ou des modèles tissulaires fonctionnels sur le plan mécanique et biologique.La présente recherche de doctorat visait donc à produire et à caractériser des constructions tubulaires 3D à base de CD, les tissus des voies respiratoires dans des conditions de culture physiologiquement pertinentes. Le premier objectif était de concevoir des constructions à base de CD et d'évaluer la réaction des fibroblastes ensemencés à la CP et à la culture dans un milieu à base de CD; de fabriquer et de caractériser des hybrides multicouches CD-fibroïne-CD ensemencés de cellules souches mésenchymateuses (CSM); et d'évaluer la différenciation.Le deuxième objectif de la présente recherche était de concevoir et de caractériser des constructions tubulaires faites de collagène dense (CTCD). Le troisième objectif était d'implanter des constructions tubulaires à base de CD comme modèle tissulaire des voies respiratoires par l'évaluation de la réponse des cellules musculaires lisses (CML) des voies respiratoires dans les CTCD en présence de stimuli mécaniques physiologiques.En leur fournissant une niche physiologiquement équivalente, et grâce à la stimulation de l'écoulement pulsatoire, in vitro, les CML des voies respiratoires ont pris leur orientation naturelle, maintenu leur phénotype contractile et amélioré les propriétés mécaniques de la CTCD grâce au remodelage matriciel. La capacité de la CTCD à transférer la stimulation physiologique pulsatile aux CSM résidentes a donné une orientation des cellules s'apparentant à leur orientation naturelle et induit l'expression phénotypique.En conclusion, les constructions tubulaires à base de collagène dense qui ont été développées et implantées sont parvenues à fournir in vitro un modèle tissulaire des voies respiratoires pour d'éventuelles études précliniques visant à reproduire les conditions physiologiques et pathologiques.
13
Chik, Tsz-kit, e 戚子傑. "Fabrication of multi-component tissue for intervertebral disc tissue engineering". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B47849447.
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Intervertebral disc tissue engineering is challenging because it involves the
integration of multiple tissues with distinct structures and compositions such as
lamellar annulus fibrosus, gel?like nucleus pulposus and cartilage endplate. Each
of them has different compositions and different structures. It is hypothesized
that integration of tissues can be enhanced with appropriate mechanical and
biological stimuli. Meanwhile, effect of torsional stimulus on cell re?orientation
in mesenchymal stem cell?collagen tubular constructs is investigated in this study.
Furthermore, it is proposed that these findings can be used to fabricate a multicomponent
unit for intervertebral disc tissue engineering. It has been
demonstrated that mechanical and biological stimuli can stabilize the interface
between osteogenic and chondrogenic differentiated constructs with enhanced
ultimate tensile stress while the phenotype of osteogenic and chondrogenic
differentiated constructs were maintained. Scanning electronic microscopic
images have shown aligned collagen fibrils and presence of calcium at the
interface, indicating the possibility of the formation of a calcified zone. In
addition, it is proven that torsional stimulus triggered re?orientation of
mesenchymal stem cells in collagen lamellae towards a preferred angle. Cell
alignments were confirmed by using a MatLab?based program to analyze the
actin filament and the cell alignment via Phalloidin and Hematoxylin staining,
respectively. Cells and actin filaments were inclined around 30o from the vertical
axis, while cells and filaments in the control group (static loading) aligned along
the vertical axis. Furthermore, a double?layers bioengineered unit was fabricated,
with intact osteogenic differentiated parts at both ends. Comparatively higher
cell density was observed at the interface between layers, demonstrating the
interactions between layers, while the phenotype of each part was maintained in
14 days culture. This study concludes that a multi?components bioengineered
unit with preferred cell alignments can be fabricated. This provides new insights
to future development of bioengineered spinal motion segment for treating late
stage disc degeneration.published_or_final_version
Mechanical Engineering
Doctoral
Doctor of Philosophy
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Banani, M. A., M. Rahmatullah, N. Farhan, Zoe Hancox, Safiyya Yousaf, Z. Arabpour, Moghaddam Z. Salehi, M. Mozafari e Farshid Sefat. "Adipose tissue-derived mesenchymal stem cells for breast tissue regeneration". Future Medicine, 2021. http://hdl.handle.net/10454/18391.
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YesWith an escalating incidence of breast cancer cases all over the world and the deleterious psychological impact that mastectomy has on patients along with several limitations of the currently applied modalities, it's plausible to seek unconventional approaches to encounter such a burgeoning issue. Breast tissue engineering may allow that chance via providing more personalized solutions which are able to regenerate, mimicking natural tissues also facing the witnessed limitations. This review is dedicated to explore the utilization of adipose tissue-derived mesenchymal stem cells for breast tissue regeneration among postmastectomy cases focusing on biomaterials and cellular aspects in terms of harvesting, isolation, differentiation and new tissue formation as well as scaffolds types, properties, material–host interaction and an in vitro breast tissue modeling.
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Kalcioglu, Zeynep Ilke. "Mechanical behavior of tissue simulants and soft tissues under extreme loading conditions". Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/79558.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 157-168).
Recent developments in computer-integrated surgery and in tissue-engineered constructs necessitate advances in experimental and analytical techniques in characterizing properties of mechanically compliant materials such as gels and soft tissues, particularly for small sample volumes. One goal of such developments is to quantitatively predict and mimic tissue deformation due to high rate impact events typical of industrial accidents and ballistic insults. This aim requires advances in mechanical characterization to establish tools and design principles for tissue simulant materials that can recapitulate the mechanical responses of hydrated soft tissues under dynamic contact-loading conditions. Given this motivation, this thesis studies the mechanical properties of compliant synthetic materials developed for tissue scaffold applications and of soft tissues, via modifying an established contact based technique for accurate, small scale characterization under fully hydrated conditions, and addresses some of the challenges in the implementation of this method. Two different engineered material systems composed of physically associating block copolymer gels, and chemically crosslinked networks including a solvent are presented as potential tissue simulants for ballistic applications, and compared directly to soft tissues from murine heart and liver. In addition to conventional quasistatic and dynamic bulk mechanical techniques that study macroscale elastic and viscoelastic properties, new methodologies are developed to study the small scale mechanical response of the aforementioned material systems to concentrated impact loading. The resistance to penetration and the energy dissipative constants are quantified in order to compare the deformation of soft tissues and mechanically optimized simulants, and to identify the underlying mechanisms by which the mechanical response of these tissue simulant candidates are modulated. Finally, given that soft tissues are biphasic in nature, atomic force microscopy enabled load relaxation experiments are utilized to develop approaches to distinguish between poroelastic and viscoelastic regimes, and to study how the anisotropy of the tissue structure affects elastic and transport properties, in order to inform the future design of tissue simulant gels that would mimic soft tissue response.
by Zeynep Ilke Kalcioglu.
Ph.D.
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Carlson, Grady E. "Dynamic Biochemical Tissue Analysis of L-selectin Ligands on Colon Cancer Tissues". Ohio University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1343932605.
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Ueda, Yuichiro. "Application of Tissue Engineering with Xenogenic Cells and Tissues for Regenerative Medicine". 京都大学 (Kyoto University), 2004. http://hdl.handle.net/2433/147657.
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Killich, Markus. "Tissue Doppler Imaging". Diss., lmu, 2007. http://nbn-resolving.de/urn:nbn:de:bvb:19-67089.
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Heidegger, Simon. "Tissue-specific migration". Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-131476.
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Dawson, Jennifer Elizabeth. "Cardiac Tissue Engineering". Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20071.
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The limited treatment options available for heart disease patients has lead to increased interest in the development of embryonic stem cell (ESC) therapies to replace heart muscle. The challenges of developing usable ESC therapeutic strategies are associated with the limited ability to obtain a pure, defined population of differentiated cardiomyocytes, and the design of in vivo cell delivery platforms to minimize cardiomyocyte loss. These challenges were addressed in Chapter 2 by designing a cardiomyocyte selectable progenitor cell line that permitted evaluation of a collagen-based scaffold for its ability to sustain stem cell-derived cardiomyocyte function (“A P19 Cardiac Cell Line as a Model for Evaluating Cardiac Tissue Engineering Biomaterials”). P19 cells enriched for cardiomyocytes were viable on a transglutaminase cross-linked collagen scaffold, and maintained their cardiomyocyte contractile phenotype in vitro while growing on the scaffold. The potential for a novel cell-surface marker to purify cardiomyocytes within ESC cultures was evaluated in Chapter 3, “Dihydropyridine Receptor (DHP-R) Surface Marker Enrichment of ES-derived Cardiomyocytes”. DHP-R is demonstrated to be upregulated at the protein and RNA transcript level during cardiomyogenesis. DHP-R positive mouse ES cells were fluorescent activated cell sorted, and the DHP-R positive cultured cells were enriched for cardiomyocytes compared to the DHP-R negative population. Finally, in Chapter 4, mouse ESCs were characterized while growing on a clinically approved collagen I/III-based scaffold modified with the RGD integrin-binding motif, (“Collagen (+RGD and –RGD) scaffolds support cardiomyogenesis after aggregation of mouse embryonic stem cells”). The collagen I/III RGD+ and RGD- scaffolds sustained ESC-derived cardiomyocyte growth and function. Notably, no significant differences in cell survival, cardiac phenotype, and cardiomyocyte function were detected with the addition of the RGD domain to the collagen scaffold. Thus, in summary, these three studies have resulted in the identification of a potential cell surface marker for ESC-derived cardiomyocyte purification, and prove that collagen-based scaffolds can sustain ES-cardiomyocyte growth and function. This has set the framework for further studies that will move the field closer to obtaining a safe and effective delivery strategy for transplanting ESCs onto human hearts.
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Somasundaram, Murali. "Intestinal tissue engineering". Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:54e0f17f-fe04-4012-b0d3-04f436e9af9a.
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Tissue engineering (TE) principles have been successfully clinically applied to treat disease affecting specific organs (e.g. trachea) but developments in some organs has lagged behind. The inability to repair or replace significantly damaged intestinal tissue remains a barrier to improving patient outcomes and the promise of Tissue Engineered Intestine (TEI) that was first made more than 20 years ago, is yet to be realised. This work explored the potential of TEI and literature review formed a basis for developing a clinically transferrable experimental model. It was hypothesised that, porcine large intestine could be retrieved from pigs and decellularized to create a biological scaffold that demonstrated favourable properties for TE, including potential for vascular perfusion and cell engraftment. Novel experiments were performed in intestinal retrieval and decellularization, resulting in scaffolds characterised by a number of methods (e.g. histology, immunohistochemistry). Assessment of the scaffold's ability to support cell engraftment required development of protocols for isolation and culture of appropriate progenitors, including adipose/bone marrow derived mesenchymal stromal cells and intestinal organoid units. Finally, in-vitro cultures combining scaffolds and cells were used to assess the ability of scaffolds to promote tissue regeneration. Perfusion decellularization methods proved effective in creating biological scaffolds that retained radiologically demonstrated vascular perfusion networks, permitting a future route for recellularization and/or transplantation. Scaffolds demonstrated retention of essential extracellular matrix components (e.g. glycosaminoglycans, collagen) and an absence of cell nuclei. Mesenchymal stem cells were isolated, cultured and combined in-vitro with scaffolds in an attempted scaled-down seeding model. Control of culture conditions was challenging and results inconclusive with respect to the scaffold's regenerative potential. The work demonstrates an exciting prospect for biological scaffold development for a clinically transferrable, semi-xenogeneic transplant or drug delivery model but further experiments in scaffold seeding are required to assess the full potential.
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Vanhook, Patricia M., Lynne M. Dunphy, M. Zycowizc e C. Luskin. "Soft Tissue Disorders". Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etsu-works/7410.
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Book Summary: Serves the needs of advanced practice nurses because it’s written by nurse practitioners for nurse practitioners, in collaboration with a physician. Organizes content around the Circle of Caring framework for nursing-based knowledge and holistic care. Explores complementary and alternative treatments for each disorder. Covers the broadest range of human disease and disorders using a systems-based approach, presenting both common complaints and common problems to help students narrow down the possible differentials to the most likely diagnosis. Considers interactions of pharmaceuticals with alternative medications and nutraceuticals. Features coverage of pathophysiology and diagnostic reasoning as well as up-to-date guidance on laboratory and diagnostic tests. Emphasizes evidence-based practice with information on evidence levels and more references to primary studies. Integrates discussions of health policy and primary care throughout the text.
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Miller, Jeri L. "Ultrasonic tissue characterization of the tongue : spectral features of tissue morphology". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0022/NQ50222.pdf.
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Liu, Xuerong. "Comparison of Methods For Estimating Tissue Components In Mixed Tissue Sample". University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1467971800.
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Golec, Karolina. "Hybrid 3D Mass Spring System for Soft Tissue Simulation". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1004/document.
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La nécessité de simulations de tissus mous, tels que les organes internes, se pose avec le progrès des domaines scientifiques et médicaux. Le but de ma thèse est de développer un nouveau modèle générique, topologique et physique, pour simuler les organes humains. Un tel modèle doit être facile à utiliser, doit pouvoir effectuer des simulations en temps réel avec un niveau de précision permettant l'utilisation à des fins médicales. Cette thèse explore de nouvelles méthodes de simulation et propose des améliorations pour la modélisation de corps déformables. Les méthodes proposées visent à pouvoir effectuer des simulations rapides, robustes et fournissant des résultats physiquement précis. L'intérêt principal de nos solutions réside dans la simulation de tissus mous élastiques a petites et grandes déformations à des fins médicales. Nous montrons que pour les méthodes existantes, la précision pour simuler librement des corps déformables ne va pas de pair avec la performance en temps de calcul. De plus, pour atteindre l'objectif de simulation rapide, de nombreuses approches déplacent certains calculs dans une étape de pré-traitement, ce qui entraîne l'impossibilité d'effectuer des opérations de modification topologiques au cours de la simulation comme la découpe ou le raffinement. Dans cette thèse, le cadre utilisé pour les simulations s'appelle TopoSim. Il est conçu pour simuler des matériaux à l'aide de systèmes masses-ressorts (MSS) avec des paramètres d'entrée spécifiques. En utilisant un MSS, qui est connu pour sa simplicité et sa capacité à effectuer des simulations temps réel, nous présentons plusieurs améliorations basé physiques pour contrôler les fonctionnalités globales du MSS qui jouent un rôle clé dans la simulation de tissus réels. La première partie de ce travail de thèse vise à reproduire une expérience réelle de simulation physique qui a étudié le comportement du tissu porcin à l'aide d'un rhéomètre rotatif. Son objectif était de modéliser un corps viscoélastique non linéaire. A partir de l'ensemble des données acquises, les auteurs de l'expérience ont dérivé une loi de comportement visco-élastique qui a ensuite été utilisée afin de la comparer avec nos résultats de simulation. Nous définissons une formulation des forces viscoélastiques non linéaires inspirée de la loi de comportement physique. La force elle-même introduit une non linéarité dans le système car elle dépend fortement de l'amplitude de l'allongement du ressort et de trois paramètres spécifiques à chaque type de tissu. La seconde partie de la thèse présente notre travail sur les forces de correction de volume permettant de modéliser correctement les changements volumétriques dans un MSS. Ces forces assurent un comportement isotrope des solides élastiques et un comportement correct du volume quel que soit la valeur du coefficient de Poisson utilisé. La méthode nécessite de résoudre deux problèmes: l'instabilité provoquant des plis et les contraintes de Cauchy. Nos solutions à ces limitations impliquent deux étapes. La première consiste à utiliser trois types de ressorts dans un maillage entièrement hexaédrique: les arêtes, les faces diagonales et les diagonales internes. Les raideurs des ressorts dans le système ont été formulées pour obéir aux lois mécaniques de base. La deuxième étape consiste à ajouter des forces de correction linéaires calculées en fonction du changement de volume et des paramètres mécaniques du tissu simulé, à savoir le coefficient de Poisson et le module de Young [etc…]The need for simulations of soft tissues, like internal organs, arises with the progress of the scientific and medical environments. The goal of my PhD is to develop a novel generic topological and physical model to simulate human organs. Such a model shall be easy to use, perform the simulations in the real time and which accuracy will allow usage for the medical purposes.This thesis explores novel simulation methods and improvement approaches for modeling deformable bodies. The methods aim at fast and robust simulations with physically accurate results. The main interest lies in simulating elastic soft tissues at small and large strains for medical purposes. We show however, that in the existing methods the accuracyto freely simulate deformable bodies and the real-time performance do not go hand in hand. Additionally, to reach the goal of simulating fast, many of the approaches move the necessary calculations to pre-computational part of the simulation, which results in inability to perform topological operations like cutting or refining.The framework used for simulations in this thesis is designed to simulate materials using Mass Spring Systems (MSS) with particular input parameters. Using Mass-Spring System, which is known for its simplicity and ability to perform fast simulations, we present several physically-based improvements to control global features of MSS which play the key role in simulation of real bodies
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Bogaert, Raymond. "Identification and characterization of type II collagen mutations". Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/6391.
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Hajeer, Mohammad Younis. "3D soft-tissue, 2D hard-tissue and psychosocial changes following orthognathic surgery". Thesis, University of Glasgow, 2003. http://theses.gla.ac.uk/3126/.
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A 3D imaging system (C3D®), based on the principles of stereophotogrammetry, has been developed for use in the assessment of facial changes following orthognathic surgery. Patients’ perception of their facial appearance before and after orthognathic surgery has been evaluated using standardised questionnaires, but few studies have tried to link this perception with the underlying two-dimensional cephalometric data. Comparisons between patients’ subjective opinions and 3D objective assessment of facial morphology have not been performed. Aims: (1) To test the reliability of the 3D imaging system; (2) to determine the effect of orthognathic surgery on the 3D soft-tissue morphology; (3) to assess skeletal changes following orthognathic surgery; (4) to evaluate soft-tissue to hard-tissue displacement ratios; (5) to ascertain the impact of orthognathic surgery on patients’ perception of their facial appearance and their psychosocial characteristics, (6) to explore the dentofacial deformity, sex and age on the psychosocial characteristics; (7) to evaluate the extent of compatibility between the cephalometric and the three-dimensional measurements and (8) to determine if the magnitude of facial soft-tissue changes affects the perception of facial changes at six months following surgery. Results and Conclusions: C3D imaging system was proved to be accurate with high reproducibility. The reproducibility of landmark identification on 3D models was high for 24 out of the 34 anthropometric landmarks (SD£0.5 mm). One volumetric algorithm in the Facial Analysis Tool had an acceptable accuracy for the assessment of volumetric changes following orthognathic surgery (mean error=0.314 cm3). The error of cephalometric method was low and the simulation of mandibular closure proved to be reproducible. 2D soft-tissue measurements were compatible with 3D measurements in terms of distances, but angular measurements showed significant differences (p<0.05).
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Brown, Andrew. "Development of an autonomous parallel action tissue grasper to minimise tissue trauma". Thesis, University of Dundee, 2014. https://discovery.dundee.ac.uk/en/studentTheses/8151b394-f604-4d5f-98c5-dc8516ac0c42.
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Trauma caused by grasping during laparoscopic surgery is something which will never be fully eradicated however efforts should be taken to reduce the potential to cause trauma by grasping. Tissue is often grasped with excessive forces for long periods of time during surgeries such as cholecystectomies and colectomies. This along with failed grasping actions and the occurrence of slip has been shown to damage the tissue. Design features often employed within graspers such as profiling and the occlusion mechanism of the instrument cause areas of high, uneven distribution of pressures on the tissue which can result in perforation or tissue tearing. By investigating these contributing factors, development of graspers with a low risk to cause damage this combined with actuating the grasping force should reduce the incidence of grasping trauma, currently at estimated at one incidence per procedure. These trauma events can lead to conversion to open surgery, peritonitis and even death. Development of an autonomous grasping instrument to detect and prevent slip by actuating the grasping force is reported. Piezoelectric sensors are used to detect incipient slip and slip events. A closed loop control system then reacts to these perceived slip events to prevent slip occurring by actuating the applied force by small increments to increase or decrease grasping force. This leads to a system in which only the required amount of force necessary to overcome pull force is applied to the tissue. Other areas of investigation to reduce tissue trauma are presented. In chapter 3 design features such as surface profiling and fenestrations are evaluated to determine the potential to cause damage. A variety of profiles and fenestrations are studied and each is reported by representing the applied force to retention force ratio which indicates how good the profile is at retaining tissue against a pull force. The aim of this study was to develop surface profiling which had a high retention force but a reduced number of high stress areas which can lead to tissue damage. Three new parallel action grasping designs are presented and evaluated using finite element analysis. Parallel action grasping is important in reducing tissue trauma as it distributes pressure evenly across the active grasping area as opposed to more conventional pivot style graspers which have high stress concentration areas in the proximal opening. Each area of study within the thesis addresses areas of concern which have been shown to cause tissue trauma and postulates viable solutions to reduce the incidences of tissue trauma during laparoscopic surgery with the ultimate aim of developing a deployable and autonomous grasping device which will detect and prevent slip.
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Hatayama, Takahide. "Regeneration of gingival tissue using in situ tissue engineering with collagen scaffold". Kyoto University, 2019. http://hdl.handle.net/2433/243271.
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Maksym, Geoffrey Nicholas. "Modelling lung tissue rheology". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ30329.pdf.
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Kilarski, Witold. "Mechanisms of Tissue Vascularization". Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4819.
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Rouwkema, Jeroen. "Prevascularized bone tissue engineering". Enschede : University of Twente [Host], 2007. http://doc.utwente.nl/57929.
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Maksym, Geoffrey N. "Modelling lung tissue theology". Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=42087.
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A model was developed to account for the static elastic behaviour of the lung tissue strip in terms of distributions of collagen and elastin fibers. Distributions of collagen fiber lengths and elastin fiber stiffnesses were determined by fitting the model to data from dog lung tissue strips. These distributions followed 1/f power-laws for more than 95% of the data. Computer simulations of two dimensional tissue strip models with 1/f distributions of collagen fiber lengths also predicted realistic stress-strain curves. The simulations illustrated the gradual development of geometric and stress heterogeneity throughout the tissue as the collagen fibers were recruited during stretch. This model suggests a mechanistic basis for the shape of the pressure-volume curve of whole lung. It also indicates how this curve may be affected by changes in tissue collagen and elastin similar to the changes occurring in the diseases of pulmonary emphysema and fibrosis. Nonparametric block-structured nonlinear models for describing both the static and dynamic stress-strain behaviour of the lung were applied to dog lung tissue strips and to whole rat lungs in vivo. Both the Wiener and Hammerstein models accounted for more than 99% of the tissue strip data, although the Hammerstein model was more consistently accurate across a range of perturbation amplitudes and operating stresses. Plastic dissipation of energy within the lung tissue strip was estimated at less than 20% of the total dissipation during slow sinusoidal cycling. The Hammerstein model was also the best of those investigated for describing the rat lung data in vivo, although there were dependencies of the model parameters on perturbation amplitude and operating point that indicate that a more complicated model is required for the whole lung. Finally, construction of a fiber recruitment model for the dynamic mechanical behaviour of lung tissue strips was attempted. However accurate reproduction of measured behaviour was no
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Dickson, Jeanette. "Predicting normal tissue radiosensitivity". Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366256.
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Mirsadraee, Saeed. "Tissue engineering of pericardium". Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426783.
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Getgood, Alan Martin John. "Articular cartilage tissue engineering". Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608764.
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Tseng, Yuan-Tsan. "Heart valve tissue engineering". Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:e67c780d-d60f-42e7-9311-dd523f9141b3.
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Since current prosthetic heart valve replacements are costly, cause medical complications, and lack the ability to regenerate, tissue-engineered heart valves are an attractive alternative. These could provide an unlimited supply of immunological-tolerated biological substitutes, which respond to patients' physiological condition and grow with them. Since collagen is a major extra cellular matrix component of the heart valve, it is ideal material for constructing scaffolds. Collagen sources have been shown to influence the manufacturing of collagen scaffolds, and two commercial sources of collagen were obtained from Sigma Aldrich and Devro PLC for comparison. Consistencies between the collagens were shown in the primary and secondary structures of the collagen, while inconsistencies were shown at the tertiary level, when a higher level of natural crosslinking in the Sigma collagen and longer polymer chains in the Devro collagen were observed. These variations were reduced and the consistency increased by introducing crosslinking via dehydrothermal treatment (DHT). Collagen scaffolds produced via freeze-drying (FD) and critical point-drying with cross-linking via DHT or 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide /N-hydroxysuccinimide (EDC/NHS) were investigated. All the scaffolds were compatible with mesenchymal stem cells (MSCs) according to the proliferation of the cells and their ability to produce ECM, without differentiating between osteogenic, chondrogenic or endothelial lineages. The FD EDC/NHS scaffold demonstrated the most suitable physical property of all. This result illustrates that FD EDC/NHS crosslinking is the most suitable scaffold investigated as a start for heart valve tissue engineering. To prepare a scaffold with a controlled local, spatial and temporal delivery of growth factor, a composite scaffold comprising poly (lactic-co-glycolic acid) (PLGA) microspheres was developed. This composite scaffold demonstrated the same compatibility to the MSCs as untreated scaffold. However, the PLGA microspheres showed an increase in the deterioration rate of Young's modulus because of the detachment of the microspheres from the scaffold via cellular degradation.
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Rosengren, Agneta. "Tissue reactions to biomaterials". Lund : Dept. of Physiology and Neuroscience, Section for Neuroendocrine Cell Biology, and the Dept. of Experimental Research, University Hospital MAS, Lund University, 1997. http://catalog.hathitrust.org/api/volumes/oclc/38986628.html.
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Bapat, S. "Tissue culture in cereals". Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1992. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/3020.
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Heus, Redha. "Approches virtuelles dédiées à la technologie des puces à tissus "Tissue MicroArrays" TMA : application à l'étude de la transformation tumorale du tissu colorectal". Phd thesis, Grenoble 1, 2009. http://www.theses.fr/2009GRE10136.
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La technique récente des puces à tissus « Tissue Micro Arrays » TMA apparaît comme un moyen indispensable d'investigation pour la validation des profils d'expression des marqueurs tumoraux en relation avec la dynamique de l'architecture tissulaire lors de la transformation tumorale. Brièvement, cette technologie consiste à regrouper, dans un seul bloc de paraffine, plusieurs centaines de petits échantillons tissulaires sous forme de carottes cylindriques prélevées à partir de différents blocs de biopsies classiques. Le sujet de thèse s'intéresse aux différents aspects de traitement d'images et de contrôle qualité liés à la technologie TMA. Les travaux de thèse sont réalisés selon deux grands axes qui retracent l'enchaînement chronologique des opérations : conception des blocs TMA, puis analyse automatique des coupes TMA. Dans un premier temps, le concept de TMA virtuel est introduit pour simuler les protocoles de prélèvement de carottes afin d'évaluer la technologie TMA. En deuxième temps, une modélisation originale de la couleur associée au diagramme de chromaticité xy, est proposée pour la détection automatique des marqueurs tumoraux au niveau des coupes TMA. Le concept de sociologie cellulaire, modélisé par le diagramme de Voronoï, est finalement adopté pour illustrer la dynamique de la distribution spatiale des cellules cancéreuses au cours de la transformation tumorale. Les méthodes développées sont appliquées à l'étude des marqueurs tumoraux du cancer colorectalThe recent technique of Tissue Micro Arrays “TMA” seams an essential way to investigate about the precise knowledge of tumour markers expression and their relation with the tissue architecture dynamic in the tumour development process. Briefly, this technology allows gathering, in a single block of paraffin, several hundreds of small cylindrical-shaped tissue-samples from different blocks of conventional tumour biopsies. This thesis focuses on different aspects of image processing and quality control related to TMA technology. The work is realized according to two main sections in agreement with chronological sequence of operations: design of TMA and automated analysis of TMA sections. As a first step, the concept of virtual TMA is introduced to simulate the protocols of core sampling to evaluate the TMA technology. In the second step, an original colour model associated with the chromaticity diagram xy is proposed for automatic detection of tumour markers in numerical TMA slides. The concept of sociology cell, modelled by Voronoï diagram, is finally adopted to illustrate the dynamics of the spatial distribution of cancer cells in the process of tumour development. The different methods developed in this work are applied to study the tumour markers of colorectal cancer
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Heus, Redha. "Approches virtuelles dédiées à la technologie des puces à tissus "Tissue MicroArrays " TMA : Application à l'étude de la transformation tumorale du tissu colorectal". Phd thesis, Université Joseph Fourier (Grenoble), 2009. http://tel.archives-ouvertes.fr/tel-00429056.
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La technique récente des puces à tissus " Tissue Micro Arrays " TMA apparaît comme un moyen indispensable d'investigation pour la validation des profils d'expression des marqueurs tumoraux en relation avec la dynamique de l'architecture tissulaire lors de la transformation tumorale. Brièvement, cette technologie consiste à regrouper, dans un seul bloc de paraffine, plusieurs centaines de petits échantillons tissulaires sous forme de carottes cylindriques prélevées à partir de différents blocs de biopsies classiques. Le sujet de thèse s'intéresse aux différents aspects de traitement d'images et de contrôle qualité liés à la technologie TMA. Les travaux de thèse sont réalisés selon deux grands axes qui retracent l'enchaînement chronologique des opérations : conception des blocs TMA, puis analyse automatique des coupes TMA. Dans un premier temps, le concept de TMA virtuel est introduit pour simuler les protocoles de prélèvement de carottes afin d'évaluer la technologie TMA. En deuxième temps, une modélisation originale de la couleur associée au diagramme de chromaticité xy, est proposée pour la détection automatique des marqueurs tumoraux au niveau des coupes TMA. Le concept de sociologie cellulaire, modélisé par le diagramme de Voronoï, est finalement adopté pour illustrer la dynamique de la distribution spatiale des cellules cancéreuses au cours de la transformation tumorale. Les méthodes développées sont appliquées à l'étude des marqueurs tumoraux du cancer colorectal.
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Yuan, Tai-Yi. "Innovative Methods to Determine Material Properties of Cartilaginous Tissues and Application for Tissue Engineering". Scholarly Repository, 2011. http://scholarlyrepository.miami.edu/oa_dissertations/607.
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Low back pain is one of the major health concerns in the US. It affects up to 80% of the population at some time during their lives. It not only causes discomfort to patients and affects their physical ability but also has a huge economic impact on society. Although the cause of low back pain is still poorly understood, it is implicated that degeneration of the intervertebral disc is the primary factor. Currently, researchers are trying to use tissue engineering approaches to develop new treatments capable of removing the degenerated disk and replacing it with a biological substitute. However, to create such a biological substitute, we need to first understand the structure-function relationship of the tissue. Only when we understand the function of the tissue, can we begin creating biological substitutes. While culturing a biological substitute, we also need methods to determine how the substitute responds to its environment. At present, there are many different types of bioreactors developed for cartilaginous tissues. However, there is a lack of a system that can detect the chemical, electrical and mechanical response noninvasively with control feedback in real-time. It is hard to provide the optimal culture environment to the substitute without knowing its response in real-time. The objective of this dissertation is to develop new methods to investigate the transport property, oxygen consumption rate and mechano-electrochemical and mechanical properties of the tissue. Because cells are responsible for the tissue health, it is necessary to understand how they can obtain nutrients under different environments, e.g. under different loading condition. In addition, with the use of a bioreactor with the capability of detecting the real-time response combined with a feedback control system, we can provide the most favorable conditions for tissue or biological substitutes to grow. The new measurement methods developed in this dissertation can contribute to further understanding the function of the tissue. The methods outlined in this dissertation can also provide new tools for future tissue engineering applications. Moreover, the findings in this dissertation can provide information for developing a more comprehensive theoretical model to elucidate the etiology of disc degeneration.
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Ralfs, Julie D. "The influence of freezing and tissue porosity on the material properties of vegetable tissues". Thesis, University of Reading, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251279.
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Swain, Robin. "Non-invasive biochemical analysis of cells, tissues and tissue constructs with Raman micro-spectroscopy". Thesis, Imperial College London, 2008. http://hdl.handle.net/10044/1/11327.
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Sandino, Velásquez Clara Inés. "Simulation of mechanoregulation and tissue differentiation in calcium phosphate scaffolds for tissue engineering". Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/6211.
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Los estímulos mecánicos son uno de los factores que afectan a la diferenciación celular en el proceso de regeneración del tejido óseo, por lo tanto, en el desarrollo de andamios para ingeniería de tejidos, se pueden aplicar las cargas mecánicas con el fin de inducir la actividad de las células. Cuando se aplican cargas mecánicas, los estímulos mecánicos específicos transmitidos a las células a nivel microscópico pueden estudiarse mediante técnicas numéricas. El objetivo de esta tesis fue estudiar la mecanoregulación de la diferenciación de tejido en andamios de fosfato de calcio utilizando modelos de elementos finitos basados en micro tomografía axial computarizada.Dos muestras de materiales porosos basados en fosfato de calcio fueron utilizadas. Se desarrollaron mallas de elementos finitos congruentes, discretizando la fase sólida y los macro poros interconectados, con el fin de tener en cuenta la morfología irregular de los andamios.
En primer lugar, se estudió la distribución de los estímulos mecánicos. La fase sólida y el fluido intersticial se simularon como material elástico lineal y como fluido Newtoniano, respectivamente. Se simuló una compresión del 0.5% en el sólido y un fluido con velocidades de entrada de 1, 10 y 100 µm/s en los poros. Se encontraron distribuciones de deformación similares en las paredes ambos materiales, con valores máximos de 1.6% en compresión y de 0.6% en tracción. En algunos poros, la velocidad del fluido aumentó a 100 y 1000 veces la velocidad de entrada. Este estudio mostró como estímulos mecánicos macroscópicos pueden causar distintos niveles de estímulos mecánicos microscópicos dentro los andamios, debido a la morfología.
A continuación se realizó un estudio en el tiempo de la diferenciación de tejido en un andamio sometido a condiciones in vitro. La compresión y la perfusión se modelaron como en el estudio anterior. Se simularon una compresión del 0.5% y una velocidad de entrada de fluido constante de 10 µm/s o una presión de entrada de fluido constante de 3 Pa. La deformación cortante octaédrica y el esfuerzo cortante del fluido se utilizaron como estímulos mecano-regulatorios basándose en la teoría de Prendergast et al. (1997). Al aplicar velocidad constante, se predijeron fluctuaciones entre los estímulos equivalentes a la formación de tejido y a la muerte celular, debido al aumento en el esfuerzo cortante del fluido cuando el tejido comienza a llenar los poros. Sin embargo, al aplicar presión constante, se predijo estímulo equivalente a la diferenciación de tejido óseo en la mitad del volumen de los poros. Estos resultados sugieren que para permitir la diferenciación de tejido, la velocidad del fluido debe disminuirse cuando el tejido empieza a mineralizarse.
Finalmente, se llevó acabo un estudio en el tiempo de la angiogénesis y de la diferenciación de tejido en un andamio bajo condiciones in vivo. La deformación cortante octaédrica y la velocidad relativa del fluido se utilizaron como estímulos mecano-regulatorios. Las fases sólida y porosa fueron tratadas como materiales poroelásticos. Se simuló la actividad individual de las células. Compresiones de 0.5 y 1% fueron simuladas. La mayoría de los vasos crecieron en los poros de la periferia del andamio y se bloquearon por las paredes. Se formaron redes capilares similares independientemente de la magnitud de deformación utilizada. Al aplicar 0.5% de compresión, estímulos correspondientes a la formación de hueso se predijeron en el 70% del volumen de los poros, sin embargo, sólo el 40% del volumen se llenó de osteoblastos debido a la falta de oxigeno. Este estudio mostró el efecto de la falta de vascularización en el centro del andamio en la diferenciación de tejido.
Ese tipo de estudios, combinados con estudios in vitro, deberían contribuir a la comprensión del proceso de diferenciación de los tejidos dentro de los andamios y por lo tanto a la mejora de los métodos de diseño de andamios.
Mechanical stimuli are one of the factors that affect cell differentiation in the process of bone tissue regeneration; therefore, in the development of scaffolds for tissue engineering, mechanical loads can be applied in order to induce cell activity. The specific mechanical stimuli transmitted to cells at a microscopic level when mechanical loads are applied can be studied using numerical techniques. The objective of this thesis was to study the mechanoregulation of tissue differentiation within calcium phosphate scaffolds using micro computed tomographed based finite element models.
Two samples of porous calcium phosphate based materials were used. Congruent finite element meshes, with the solid phase and the interconnected pores discretized, were developed in order to account for the scaffold irregular morphology.
First, a study of the distribution of mechanical stimuli was performed. The solid phase and the fluid flow within the pores were modeled as linear elastic solid material and Newtonian fluid respectively. Compressive strains of 0.5% of total deformation applied to the solid and interstitial fluid flows with inlet velocities of 1, 10 and 100 µm/s applied to the pores were simulated. Similar strain distributions for both materials were found, with compressive and tensile strain maximal values of 1.6% and 0.6% respectively. For the fluid flow models, the fluid velocity in some of the scaffold pores increased to 100 and 1000 times the inlet velocity. This study showed how mechanical loads and fluid flow applied to the scaffolds caused different levels of mechanical stimuli within the samples according to the morphology of the materials.
Next, a study of the mechanoregulation of tissue differentiation over time in a scaffold subjected to in vitro loads was performed. The solid phase and the fluid flow were modeled as in the study described above. Compressive strain of 0.5% and fluid flow with constant inlet velocity of 10 µm/s or constant inlet pressure of 3 Pa were applied. Octahedral shear strain and fluid shear stress were used as mechano-regulatory stimuli based on the theory of Prendergast et al. (1997). When a constant velocity was simulated, fluctuations between stimuli equivalent to tissue formation and cell death were predicted due to the increase in the fluid shear stress when tissue started to fill the pores. However, when constant pressure was applied, stimuli equivalent to bone formation were predicted in about half of the pore volume. These results suggest that in order to allow tissue differentiation within a scaffold, the fluid velocity should be decreased when tissue starts mineralizing.
Finally, a study of the angiogenesis and the mechanoregulation of tissue differentiation over time in a scaffold subjected to in vivo conditions was performed. Octahedral shear strain and relative fluid velocity were used as mechano-regulatory stimuli. The solid and pore phases were treated as poroelastic materials. Individual cell activity was simulated within the pore domain. Compressive strains of 0.5 and 1% of total deformation were simulated. Most vessels grew in the pores at the periphery of the scaffolds and were blocked by the scaffold walls. Similar capillary networks were formed independently of the magnitude of the mechanical strain applied. When 0.5% of strain was applied, 70% of the pore volume was affected by mechano-regulatory stimuli corresponding to bone formation; however, because of the lack of oxygen, only 40% of the volume was filled with osteoblasts. This study showed the effect of the lack of vascularization in the center of the scaffold on the tissue differentiation.
Such kind of studies, combined with in vitro studies, should contribute to the understanding of the process of tissue differentiation within the constructs and therefore to the improvement of scaffold design methods.
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Starly, Binil Sun Wei. "Biomimetic design and fabrication of tissue engineered scaffolds using computer aided tissue engineering /". Philadelphia, Pa. : Drexel University, 2006. http://hdl.handle.net/1860/1114.
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Walsh, Joseph Tonry. "Pulsed laser ablation of tissue : analysis of the removal process and tissue healing". Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14412.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Harvard-MIT Division of Health Sciences and Technology Program in Medical Engineering and Medical Physics, 1988.Includes bibliographical references.
by Joseph T. Walsh, Jr.
Ph.D.
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Rotenberg, Shaun. "Blood Flow, Tissue Thickness, and Molecular Changes during Connective Tissue Graft Early Healing". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1273335634.
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Ahn, Jinsoo. "Roles of Adipose Tissue-Derived Factors in Adipose Tissue Development and Lipid Metabolism". The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1430496153.
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Chhaya, Mohit Prashant. "Additive tissue manufacturing for breast reconstruction: Combining CAD/CAM with adipose tissue engineering". Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/84762/9/Mohit_Prashant_Chhaya_Thesis.pdf.
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The primary aim of this multidisciplinary project was to develop a new generation of breast implants. Disrupting the currently prevailing paradigm of silicone implants which permanently introduce a foreign body into mastectomy patients, highly porous implants developed as part of this PhD project are biodegradable by the body and augment the growth of natural tissue. Our technology platform leverages computer-assisted-design which allows us to manufacture fully patient-specific implants based on a personalised medicine approach. Multiple animal studies conducted in this project have shown that the polymeric implant slowly degrades within the body harmlessly while the body's own tissue forms concurrently.