• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 101
  • 93
  • 47
  • 15
  • 7
  • 7
  • 5
  • 5
  • 4
  • 1
  • Tagged with
  • 308
  • 308
  • 138
  • 122
  • 92
  • 81
  • 62
  • 59
  • 57
  • 56
  • 55
  • 39
  • 38
  • 32
  • 30
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Cell therapy for chronic liver disease

Thomas, James A. January 2015 (has links)
There is a growing literature of clinical studies of bone marrow (BM) cell therapy for liver cirrhosis. At present, the optimum choice of cell type(s) and the mechanism(s) of effect remain undefined. Cells of the monocyte-macrophage lineage have key roles in the development and resolution of liver fibrosis. Therefore, I tested the therapeutic effects of these cells in the context of experimental murine liver fibrosis. The effects of unmanipulated, syngeneic macrophages, their specific BM precursors and unfractionated (whole) BM cells were examined in the iterative carbon tetrachloride model of liver fibrosis. BM-derived macrophage (BMM) delivery resulted in early chemokine upregulation with the hepatic recruitment of endogenous macrophages and neutrophils. These cells delivered matrix metalloproteinases-13 and -9 respectively, into the hepatic scar. The effector cell infiltrate was accompanied by increased levels of the anti-inflammatory cytokine IL-10. A reduction in hepatic myofibroblasts was followed by reduced fibrosis detected 4 weeks after macrophage infusion. Serum albumin levels were elevated at this time. Upregulation of the liver progenitor cell mitogen TWEAK preceded expansion of the progenitor cell compartment. BMM delivery increased hepatic expression of cytokines with reparative effects (including colony stimulating factor-1, insulin-like growth factor-1 and vascular endothelial growth factor). In contrast to the effects of differentiated macrophages, liver fibrosis was not significantly improved by the application of macrophage precursors and was exacerbated by whole BM. BMMs did not affect liver fibrosis or regeneration in the 1% DDC model of biliary disease. These effects were only detected following the intraportal delivery of BM cells. The peripheral (tail) vein administration of BMMs, either singly or repeatedly did not recapitulate the therapeutic phenotype. This was investigated by in vivo tracking of BMMs constitutively expressing green fluorescent protein (GFP). The peripheral administration route resulted in the early (1 hour) accumulation of BMMs within the pulmonary system. This was followed by delayed hepatic engraftment, which was also numerically reduced (< 30%) compared with intraportal administration. Macrophage cell therapy improves clinically relevant parameters in experimental chronic liver injury. Paracrine signalling to endogenous cells amplifies the effect. The benefits from this single, defined cell type suggest clinical potential.
22

Submucosa intestinal suína acelular e semeada com células musculares homólogas na reparação tecidual da bexiga de cães

Rossetto, Victor José Vieira [UNESP] 14 May 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-05-14Bitstream added on 2014-06-13T19:09:55Z : No. of bitstreams: 1 rossetto_vjv_me_botfmvz_parcial.pdf: 44582 bytes, checksum: 3c3725afe05c19146568796a0ee21ac3 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / As indicações para a cirurgia reparadora da bexiga abrangem traumas graves com perda tecidual extensa, neoplasias, cistites intersticiais, disfunções neurológicas e anormalidades congênitas. Devido a inúmeras complicações associadas às técnicas de cistoplastia com o emprego de segmentos gastrointestinais, o presente estudo teve como objetivo analisar comparativamente a reparação anatômica da bexiga de cães utilizandose a submucosa intestinal suína (SIS) acelular e semeada com células musculares lisas homólogas (CMLH), bem como avaliar as possíveis complicações e efeitos colaterais inerentes a cada um dos tipos de enxerto empregados. Para tal foram utilizados 10 cães adultos, fêmeas, subdivididos em dois grupos, sendo: Grupo Controle (GC), constituído por cinco animais submetidos à cistoplastia com SIS; e Grupo Tratado (GT), constituído por cinco animais submetidos à cistoplastia com SIS semeada com CMLH. As células foram obtidas a partir de fragmentos de espessura completa, provenientes de bexigas de cães que vieram a óbito por motivos não infecciosos ou neoplásicos, cultivadas e expandidas in vitro. Em todos os grupos foi criado um defeito de 3 cm x 2 cm, preservando-se a região do trígono vesical, o qual foi reparado pelos respectivos implantes. Os cães de ambos os grupos foram submetidos à biópsia cirúrgica com 60 dias de pós-operatório, sendo essas obtidas da área central do tecido neoformado e da adjacência entre o mesmo e a bexiga original. Após a implantação dos enxertos, os animais foram avaliados por meio de exames clínico, ultrassonográfico abdominal e laboratoriais. Todas as amostras foram destinadas à avaliação histológica pelas colorações de H/E e Tricromio de Masson, analisadas com um fotomicroscópio Nikon conectado ao sistema de análise de imagem ImageJ. Não foram... / Not available
23

Submucosa intestinal suína acelular e semeada com células musculares homólogas na reparação tecidual da bexiga de cães /

Rossetto, Victor José Vieira. January 2012 (has links)
Orientador: Cláudia Valéria Seullner Brandão / Coorientador: Lígia Souza Lima Silveira da Mota / Banca: Juliany Gomes Quitzan / Banca: Bruno Watanabe Minto / Resumo: As indicações para a cirurgia reparadora da bexiga abrangem traumas graves com perda tecidual extensa, neoplasias, cistites intersticiais, disfunções neurológicas e anormalidades congênitas. Devido a inúmeras complicações associadas às técnicas de cistoplastia com o emprego de segmentos gastrointestinais, o presente estudo teve como objetivo analisar comparativamente a reparação anatômica da bexiga de cães utilizandose a submucosa intestinal suína (SIS) acelular e semeada com células musculares lisas homólogas (CMLH), bem como avaliar as possíveis complicações e efeitos colaterais inerentes a cada um dos tipos de enxerto empregados. Para tal foram utilizados 10 cães adultos, fêmeas, subdivididos em dois grupos, sendo: Grupo Controle (GC), constituído por cinco animais submetidos à cistoplastia com SIS; e Grupo Tratado (GT), constituído por cinco animais submetidos à cistoplastia com SIS semeada com CMLH. As células foram obtidas a partir de fragmentos de espessura completa, provenientes de bexigas de cães que vieram a óbito por motivos não infecciosos ou neoplásicos, cultivadas e expandidas in vitro. Em todos os grupos foi criado um defeito de 3 cm x 2 cm, preservando-se a região do trígono vesical, o qual foi reparado pelos respectivos implantes. Os cães de ambos os grupos foram submetidos à biópsia cirúrgica com 60 dias de pós-operatório, sendo essas obtidas da área central do tecido neoformado e da adjacência entre o mesmo e a bexiga original. Após a implantação dos enxertos, os animais foram avaliados por meio de exames clínico, ultrassonográfico abdominal e laboratoriais. Todas as amostras foram destinadas à avaliação histológica pelas colorações de H/E e Tricromio de Masson, analisadas com um fotomicroscópio Nikon conectado ao sistema de análise de imagem ImageJ. Não foram... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Not available / Mestre
24

Use of a Collagen I Matrix to Enhance the Potential of Circulating Angiogenic Cells (CACs) for Therapy

Ostojic, Aleksandra January 2015 (has links)
Acute myocardial infarction (MI) is the end result of many cardiovascular diseases and is one of the leading causes of death in the western world. Cell therapy, using circulating angiogenic cells (CACs) or CD34+ cells from peripheral blood, is one approach under investigation for restoring blood flow and function to the ischemic heart. However, the numbers of CACs and CD34+ circulating cells are inversely proportional to the severity of cardiovascular disease and age; therefore, there is a need to increase their numbers and/or function for therapy. One possibility is to enhance the therapeutic potential of the cells with the use of a biomaterial. In this study, we used a collagen matrix to culture human CD34+ circulating cells, and evaluated the effect of the matrix on CD34+ cell properties and function. The matrix was able to successfully increase proliferation, migration, CD34+ phenotype and branching in an angiogenesis assay. These functional benefits may be associated with the sonic hedgehog (Shh) pathway. The collagen matrix was previously shown to enhance the function of healthy CACs, but its ability to do the same for CACs from coronary artery disease patients is unknown. In this study, the matrix was shown to enhance the viability, proliferation and angiogenic potential of patient CACs. Furthermore, gene expression for integrins and Shh pathway components in the sub-population of CD34+ cells was similar between patient and healthy donors when isolated from CACs. This work provides insight into the mechanisms for the observed matrix-enhanced function of therapeutic CACs and CD34+ cells from both healthy and CAD patient donors.
25

High Frequency Production of T Cell-Derived iPSC Clones Capable of Generating Potent Cytotoxic T Cells / T細胞から作製したiPS細胞は高頻度で強力なキラーT細胞を再生する能力を有する

Nagano, Seiji 23 March 2020 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22347号 / 医博第4588号 / 新制||医||1042(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 生田 宏一, 教授 江藤 浩之, 教授 濵﨑 洋子 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
26

A nonhuman primate model of liver fibrosis towards cell therapy for liver cirrhosis / 肝硬変に対する細胞療法の確立のための非ヒト霊長類肝線維症モデルの開発

Yasuda, Katsutaro 23 September 2020 (has links)
京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13371号 / 論医博第2208号 / 新制||医||1047(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 川口 義弥, 教授 妹尾 浩, 教授 浅野 雅秀 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM
27

Oxidized fibrin alginate microbeads to treat vascular calcification

Macha, Brittany Nichole 09 December 2022 (has links) (PDF)
Calcification is linked to a high prevalence of cardiovascular events and mortality due to arterial stiffness. Stiffening of the arteries in the case of medial calcification is due to hydroxyapatite mineral deposited in the artery thus leading to the loss of elastin. A possibility of removing this rogue mineral along the vessel walls could be the use of osteoclasts. Osteoclasts, a type of osteocyte, have the unique ability to absorb bone in the bone turnover process. It is proposed that in the future, osteoclasts be delivered to the site of mineralization through oxidized alginate-fibrin microbeads. Alginate hydrogels have proven great in drug delivery and could be a revolutionary cell delivery device to provide care for multitudes of people suffering from adjacent cardiovascular health problems such as arterial stiffness.
28

Impact of Primary Myoblasts on Macrophage Polarization In-Vitro

Welch, Olivia 01 March 2022 (has links) (PDF)
Peripheral artery disease (PAD) is characterized by the development of atherosclerotic plaques on arterial walls, leading to the narrowing of blood vessels, resulting in ischemia in the downstream tissue. In the United States, 12% of the adult population is affected by PAD and its related symptoms. Current surgical revascularization techniques can be effective in part of the patient population, but there is a need for other options. Alternatively, collateral blood vessels, or natural bypass arteries, enlarge to increase blood flow to the ischemic tissue in a process called arteriogenesis, which has been studied as a therapeutic option. Cell-based therapies, such as BM-MNCs, have been investigated as means to enhance arteriogenesis, but have largely failed in clinical trials. An alternative cell-based therapy candidate are myoblasts, or muscle progenitor cells. Myoblasts increase arteriogenesis in murine models and are known to interact with macrophages, which are immune cells that are primary regulators of arteriogenesis. Macrophages can polarize to inflammatory (M1) and regenerative (M2) phenotypes, with the M2 phenotype promoting enhanced arteriogenesis. This interaction suggests that myoblasts may be signaling macrophage polarization to enhance arteriogenesis. The purpose of this study was to determine if myoblasts in vitro can affect macrophage polarization into inflammatory (M1) or regenerative (M2) phenotypes. Protocols for macrophage culture and polarization were implemented, and then macrophages were co-cultured with myoblasts for 24 hours to assess the effects in vitro. Concentrations of known inflammatory (TNF-a) and regenerative (IL-10) cytokines released by macrophages were measured after co-culture with myoblasts. Surprisingly, macrophages co-cultured with myoblasts showed a decrease in both TNF-a and IL-10 compared to macrophages cultured alone. Morphology changes of macrophages were also measured after co-culture, with, surprisingly, little difference in the groups co-cultured with myoblasts. Pilot experiments suggest there may be an initial lag time greater than 24 hours for myoblasts to affect macrophage phenotype. Future work ideally will include longer time points and optimizing viability and proliferation of myoblasts in co-culture settings.
29

Macrophage-mediated regulation of joint homeostasis

Menarim, Bruno C. 06 November 2019 (has links)
Osteoarthritis (OA) is the leading cause of musculoskeletal disability in people and horses, and is characterized by progressive joint degeneration. There is a critical need for a better understanding of disease processes leading to OA in order to develop more efficient therapies. A shared feature among different arthritic conditions is chronic synovitis. Macrophages are the main drivers of synovitis and can display pro-inflammatory (M1) or pro-resolving responses (M2). Macrophages promote joint health through phagocytic and secretory activities; however, when these functions are overwhelmed, macrophages upregulate inflammation, recruiting more cells to counteract damage. Once cell recruitment is efficiently accomplished, macrophages coordinate tissue repair and further resolution of inflammation. Bone marrow mononuclear cells (BMNC) are a source of macrophages used to treat inflammation and produce essential molecules for cartilage metabolism; however, little information exists regarding their use in joints. The studies presented in this dissertation focus on understanding the dual role of macrophages in driving and resolving synovitis and how to harness their therapeutic potential. In the first study, patterns of macrophage phenotypes (M1:M2) in healthy and osteoarthritic equine synovium were compared and correlated with gross pathology, histology, and synovial fluid cytokines. M1 and M2 markers were co-expressed in normal and osteoarthritic joints, varying in intensity of expression according to degree of inflammation. Concentrations of synovial fluid IL-10, a macrophage-produced cytokine that is vital for chondrocyte recovery from injury, was lower in OA joints. The combined findings of this study suggest homeostatic mechanisms from synovial macrophages in OA may be overwhelmed, preventing inflammation resolution. In the second study we investigated the response of BMNC to normal (SF) and inflamed synovial fluid (ISF). BMNC cultured in autologous SF or ISF developed into macrophage cultures that were more confluent in ISF (~100%) than SF (~25%), and exhibited phenotypes that were ultimately similar to cells native to normal joints. BMNC cultured in SF or ISF were neither M1 nor M2, but exhibited aspects of both phenotypes and a regulatory response, characterized by increasing counts of IL-10+ macrophages, decreasing concentrations of IL-1β, and progressively increasing concentrations of IL-10 and IGF-1, all more marked in ISF. These findings suggest that homeostatic mechanisms were preserved over time, and potentially favored by macrophage proliferation. Our data suggest that BMNC therapy could potentiate the macrophage- and IL-10-associated mechanisms of joint homeostasis lost in OA. Finally, using an equine model of synovitis, the last study investigated the response of normal and inflamed joints to autologous BMNC injection. Inflamed joints treated with BMNC showed gross and analytical improvements in synovial fluid and synovial membrane, with increasing numbers of regulatory macrophages and synovial fluid concentrations of IL-10, not observed in saline-treated controls. Autologous BMNC are readily available, downregulate synovitis through macrophage-associated effects, and can benefit thousands of patients with OA. Combined, the results of these studies support the role of macrophage-driven synovial homeostasis and identified a therapeutic way to recover homeostatic mechanisms of synovial macrophages lost during chronic inflammation. Our findings also uncover new research directions and methods for future studies targeting modulation of joint inflammation. / Doctor of Philosophy / Osteoarthritis (OA) is a common cause of joint deterioration in people and horses. Current treatments provide limited recovery of joint function, creating an urgent need for more efficient therapies; however, development of new treatments requires better understanding of the mechanism causing OA. A shared characteristic among many arthritic conditions is long-standing inflammation. Cells called macrophages are the main drivers of joint inflammation and can exert pro- and anti-inflammatory effects. Macrophages promote joint health by clearing aggressor agents and secreting molecules required for optimal joint function. However, when these housekeeping functions are overwhelmed by damage, macrophages drive inflammation recruiting more cells to cope with increased demands for repair. If this process is efficiently accomplished, macrophages then resolve inflammation, recovering joint health. Macrophages in the bone marrow (BMNC - bone marrow mononuclear cells) are used to treat inflammation in several tissues and are known to produce molecules essential for joint health. Although little information exists regarding their use in joints, studies treating different organs suggest it can provide high rewards. The studies presented in this dissertation focused on understanding the dual function of macrophages in driving and controlling joint inflammation, and harnessed their therapeutic potential. In the first study, macrophages were investigated in normal and OA-affected joints, and curiously exhibited a hybrid pro- and anti-inflammatory identity in both groups. The indicators of this mixed identity were more markedly expressed in arthritic joints showing gross inflammation. Low levels of a macrophage-derived anti-inflammatory protein called IL-10 were detected in OA joints. The results of this study suggest that anti-inflammatory mechanisms from macrophages may be overwhelmed in OA-affected joints, preventing inflammation to be resolved, and that recovering this anti-inflammatory function may aid in the treatment of OA. In the second study we investigated how the incubation of BMNC in fluid from normal and inflamed joints affects the response of macrophages. Similar to what we observed in the first study, BMNC incubated in both normal and inflamed joint fluid induced macrophages to develop a hybrid identity that was ultimately similar to native cells from normal joints. Macrophages proliferated more when incubated in fluid from inflamed joints. Macrophages in both groups produced anti-inflammatory effects with high levels of IL-10 that were highest in ISF cultures. These observations suggest that higher proliferation of macrophages in inflamed joint fluid helped preserve anti-inflammatory mechanisms. Therefore, our study suggests that joint injection with BMNC could maximize macrophage- and IL-10-associated mechanisms required to resolve joint inflammation. The third and final study investigated the response of normal and inflamed joints to BMNC injection using a model of joint inflammation in horses. Inflamed joints treated with BMNC showed visual and laboratorial markers of improvement, with increasing numbers of macrophages and concentrations of IL-10 in the joint fluid, which remained lower in joints treated with placebo. BMNC provide means to recover macrophage-associated effects required to control joint inflammation and can benefit thousands of patients with OA. Together, the results of these studies show that macrophages are biased promoters of joint health, leading to inflammation when their anti-inflammatory mechanisms are overwhelmed. Replenishing inflamed joints with healthy macrophages maximizes their anti-inflammatory effects, favoring the recovery of a healthy articular environment.
30

Enabling late-stage translation of regenerative medicine based products

Singh, Pawanbir January 2010 (has links)
The primary aim of the thesis is to contribute to demonstrating how established and emerging science in the regenerative medicine (RM) domain can be translated into profitable commercial practice, and generate clinically- and cost-effective therapies. It achieves this by exploring and assessing underlying economics, including investment readiness and economic assessment, exploring regulatory and reimbursement frameworks, developing stem cell culture systems and assessing fit with clinical practice. The thesis is the first public domain wide-ranging analysis of business trends in the production, manufacturing and supply segments of the RM industry. It analyses the clinical potential of the domain as well as the translational and commercial challenges facing the industry. The industry is at a turning point as big pharmaceutical companies engage with RM in order to explore technologies as potential therapeutics and discovery tools. This unlocks the industry by confirming an exit path for RM based small- and medium-sized enterprises. Translation has come to be recognised as a core issue in the overall space and translation of regenerative therapies into the clinic is presently challenging, high-risk and expensive. This research addresses the question what are the mechanisms required to enable translation of emerging scientific knowledge into commercially viable clinical RM products? These mechanisms are particularly important as their creation involves and requires major investment decisions, which can determine the success or failure of RM developments and indeed of the companies concerned. The lack of well-established business models and the complexity of the domain suggested a conceptual approach drawing upon relevant literature from product and process development, applied business and revenue models, technological evolution and capital market ingenuity. The research was carried out in two phases. The first phase was concerned with identification of key challenges and mapping the overall industry emergence including emergence of related regulations to provide a context and framework for understanding the domain. Based on the emergence mapping a timeline of key parallel factors was identified, and their inherent connections explored to identify transforming events affecting and influencing multiple factors on the journey to clinical success within a business environment. This creates the reference model. The second phase was concerned with manufacturing a stem cell based therapeutic and applying health economic principles to determine available headroom for investment, cost of goods and return on investment, taking hearing disorders as a case exemplar, and exploring the behaviour of the net present value curve to identify key parameters affecting the economic positioning of this novel regime. A key output of the research is the investment readiness reference model. It integrates key RM business issues against reducing uncertainty and increasing value. The model argues that the complex nature of RM products means that the issues affecting industry emergence and development go well beyond the primarily scientific and technological concerns on which much current research focuses. The performance of RM firms ultimately hinges upon the successful clinical application of their developed products, the key step for creating and realising value, and their ability to deal with the fundamental business issues specific to the area. The framework deals with these business issues, which are investment & technology readiness, business models, organisational challenges, public policy and industry emergence. This thesis explores ideas that may bridge the chasm between the promise and reality of RM i.e. mechanisms to enable late stage translation of RM products. It links technological capability and business models for firms in the domain. Furthermore, it offers a unique perspective on the nature and characteristics of investment readiness and financial assessment, specifically identifying key parameters affecting economic positioning. The key contributions are therefore: New insights into the key challenges involved in realising the commercial potential of cell based therapeutics. Technology road mapping to link fundamental enabling technological capability for developing RM products with robust business plans integrating strategy, technology development and the regulatory and reimbursement framework. A generic investment readiness reference model generated from the enabling technology, value and supply chain structures to identify key indicators and characteristics of industry readiness. A novel experimental programme demonstrating expansion, maintenance and differentiation of human embryonic stem cells by manual and automated methods. New insights into economic positioning by mapping net present value, and economic analysis by estimating available headroom, cost of goods and return on investment for a putative hearing therapeutic.

Page generated in 0.1467 seconds