Thesis (M.Sc.)--York University, 2004. Graduate Programme in Biology. / Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url%5Fver=Z39.88-2004&res%5Fdat=xri:pqdiss &rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR11866

Thesis (Ph.D.)--York University, 2004. Graduate Programme in Biology. / Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ99209

Thesis (M.S.)--University of Missouri-Columbia, 2006. / "December 2006" The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Includes bibliographical references.

Thesis (Ph. D.)--Biomedical Engineering, Georgia Institute of Technology, 2007. / David Harrison, Committee Member ; Ravi Bellamkonda, Committee Member ; Larry McIntire, Committee Member ; Oskar Skrinjar, Committee Member ; W. Robert Taylor, Committee Chair ; Robert Guldberg, Committee Chair.

Thesis (M.S. in animal science)--Washington State University, May 2007. / Includes bibliographical references.

The composition and conformational state of biological molecules have a profound influence on cell behavior and large-scale processes including development and disease progression. Fibronectin fibers are a prevalent component of the extracellular matrix that are believed to adopt a wide array conformations with different functions. Two factors that are hypothesized to regulate fibronectin conformation, and hence fibronectin biological function, are allosteric regulators, such as heparan sulfates, and mechanical strain. However, the relative influence of allosteric regulators and mechanical forces on fibronectin conformation has not been determined. This conformational regulation is especially important in the context of the heparin 2 binding domain (modules III12 to III14), which is known to bind and present numerous growth factors, such as vascular endothelial growth factor, to cells. This thesis will highlight three contributions to this field. First, a new, and remarkably simple technique was developed that permits the detection of the non-equilibrium fibronectin conformations. This technique is founded on the identification of monoclonal antibodies that have altered affinities for fibronectin based on heparin treatment or mechanical strain dependence, or that bind fibronectin equally well in all conditions. Second, the impact of both heparin and mechanical strain on the binding of VEGF to the hep2 region of fibronectin was investigated. It was discovered that both strain and heparin co-regulate VEGF binding. Finally, studies of cell attachment and migration on single fibers of fibronectin with controlled strain states provided the first direct evidence that mechanical strain regulates cell attachment, spreading, and migration on a fibronectin matrix. This body of work demonstrating that the conformational changes in fibronectin lead to altered biological activity has broad impact in a number of fields due to the ubiquitous presence and requirement of fibronectin in cell and tissue function.

Made available in DSpace on 2014-06-11T19:25:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-30Bitstream added on 2014-06-13T19:32:30Z : No. of bitstreams: 1 guerra_dm_me_botib.pdf: 2345678 bytes, checksum: 3a29cbd28a1d454f240afad94975996e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A compreensão dos mecanismos moleculares controladores do desenvolvimento, função e regressão do CL bovino é necessária para o aprimoramento da manipulação hormonal ovariana. Fortes evidências sugerem o envolvimento de fatores de crescimento fibroblástico (FGFs) na regulação do crescimento e regressão do CL. “Splicing” alternativo de 4 genes formam sete subtipos de FGFRs com afinidade variável por diferentes FGFs. Os membros da subfamília do FGF8 (FGF8, 17 e 18) ativam eficientemente o FGFR3C e 4 e podem atuar em cooperação nos tecidos que expressão estes receptores. O objetivo deste trabalho foi determinar o padrão de expressão dos FGFRs e dos membros da subfamília do FGF8 no CL bovino (CL). Os CLs foram obtidos de ovários de abatedouro e classificados em 4 estádios de desenvolvimento (estádio/1= corpo hemorrágico, estádio/2= CL em desenvolvimento, estádio/3= CL maduro/início da luteólise funcional e estádio/4= luteólise estrutural). O RNAm foi mensurado por PCR semiquantitativo e a proteína localizada por imunohistoquímica. A expressão do RNAm codificante das isoformas ‘B’ e ‘C’ de FGFR1 e FGFR2 foi detectada no CL bovino por PCR associado à eletroforese e foi acompanhada pela localização da proteína nas pequenas e grandes células luteínicas. A expressão do RNAm do FGFR1C e 2C não variou durante o desenvolvimento luteínico, distintamente a expressão do FGFR1B aumentou no estádio 3. Embora os FGFRs 3B, 3C e 4 tenham sido detectados de forma inconsistente por PCR associado à eletroforese, o RNAm do FGFR3C e FGFR4 foram detectados por PCR em tempo real em todos os estádios do desenvolvimento luteínico. O RNAm do FGF18 foi detectado por PCR em tempo real em todos os estádios do desenvolvimento luteínico e sua abundancia do RNAm do FGF18 foi maior no estádio 3 comparado com os estádios 1, 2 e 4. Em contraste, os RNAm do FGF8 e 17... / The molecular mechanisms controlling the development, function and regression of the bovine corpus luteum are necessary for the improvement of reproductive biotechnologies. Strong evidence suggests the involvement of fibroblast growth factors (FGFs) in the regulation of growth, and regression of the corpus luteum (CL). Alternative splicing of 4 genes give rise to seven subtypes of FGFRs with varying affinity for different FGFs. FGF8 subfamily members (FGF8, 17 and 18) efficiently activate FGFR3C and FGFR4 and may act in cooperation in tissues expressing these receptors. The objective of the present study was to determine the pattern of expression of FGF8 subfamily members and FGFRs in the bovine CL. Bovine CLs were obtained from abattoir ovaries and classed into four stages of development (stage 1= corpus hemorragicum, stage 2= developing CL, stage 3= mature/early functional luteolysis CL, and stage 4= structural luteolysis). Expression of mRNA was measured by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) followed by gel analysis (FGFR1-4) and real time RT-PCR (FGF8 subfamily members, FGFR3C and FGFR4) and proteins were localized by immunohistochemistry. Expression of mRNA encoding ‘B’ and ‘C’ spliced forms of FGFR1 and FGFR2 was readily detected in the bovine CL and was accompanied by isoform non-specific protein localization. FGFR1C and FGFR2C mRNA expression did not vary throughout CL lifespan, whereas FGFR1B was upregulated in the mature CL (stage III). FGFR3B, FGFR3C and FGFR4 expression was inconsistent in the bovine CL as assessed by PCR associated with gel analysis. FGF18, FGFR3C and FGFR4 mRNA was detected by real time PCR in all four developmental stages, and FGF18 mRNA abundance was higher in stage 3 (2.89  0.05; mean ± SEM) compared with stages 1 (0.3  0.27), 2 (0.56  1.27) and 4 (0.99  0.32). The m RNA expression ... (Complete abstract click electronic access below)

CONTEXTO: A secreção de prolactina (PRL) e a expressão de seu gene são inibidas pela dopamina. Prolactinomas são os adenomas hipofisários funcionantes mais freqüentes, sendo que os agonistas dopaminérgicos são a primeira escolha para seu tratamento. No entanto, uma porcentagem dos pacientes é resistente aos agonistas dopaminérgicos. OBJETIVO: Como os mecanismos envolvidos na resistência aos agonistas dopaminérgicos não são totalmente compreendidos, o objetivo deste estudo foi obter mais informações no que diz respeito às alterações moleculares entre os prolactinomas sensíveis e resistentes aos agonistas dopaminérgicos. PACIENTES: O tecido tumoral de 22 pacientes com prolactinomas foram coletados e classificados como sensíveis ou resistentes (incluindo aqueles com crescimento tumoral) de acordo com sua resposta clínica e laboratorial aos agonistas dopaminérgicos. MÉTODOS: A expressão de 7 genes foi avaliada por Real Time polymerase chain reaction: gene do receptor de dopamina tipo 2 (DRD2), do fator de crescimento neural beta (NGF?) e de seu receptor (NGFR), dos receptores de estrógeno alfa (ESR1) e beta (ESR2), do pituitary tumor transforming gene (PTTG) e da metalotioneína 3 (MT3). RESULTADOS: A expressão mediana de DRD2 e de NGFR nos pacientes sensíveis foi significativamente maior quando comparada aos resistentes (p= 0.016 e p= 0.009, respectivamente). Além disso, ambas expressões estiveram significativamente correlacionadas positivamente com a redução da PRL durante o tratamento (r= ?0.66; p= 0.002 e r= 0.57; p= 0.017; respectivamente). Uma correlação positiva foi encontrada entre a mediana de expressão do NGF? e do DRD2 (r=0.53; p=0.023) e entre a mediana de expressão do PTTG e do ESR2 (r=0.66; p=0.008). também houve correlação entre a os valores de PRL sérica antes do tratamento e a mediana de expressão do gene do ESR2 (r=0.53, p=0.04). Não foi encontrada nenhuma correlação entre a expressão do gene da MT3 e a sensibilidade ou resistência aos agonistas dopaminérgicos. CONCLUSÕES: A expressão do gene do DRD2 e do NGFR estão relacionadas com a sensibilidade dos prolactinomas aos agonistas dopaminérgicos, enquanto a expressão do gene do PTTG e do ESR2 podem ter alguma relação com a agressividade tumoral. A resposta dos prolactinomas aos agonistas dopaminérgicos deve ser vista como um espectro variando do tumor mais sensível ao mais resistente com crescimento / CONTEXT: Prolactin (PRL) secretion and its gene expression are inhibited by dopamine. Prolactinomas are the most common secreting pituitary adenomas, with dopamine agonists being the first choice for their treatment. However, a subset of patients is resistant to dopamine agonists. OBJECTIVE: As the mechanisms involved in dopamine agonists resistance are not fully understood, the aim of this study was to get new insights regarding the molecular differences between prolactinomas responsive and resistant to dopamine agonists. PATIENTS: Tumor tissue of 22 patients harboring prolactinomas were collected and classified as responsive or resistant (including the ones with tumor growth) according to their clinical and laboratorial response to dopamine agonists. METHODS: The expression of 7 genes was evaluated by Real Time polymerase chain reaction: dopamine receptor type 2 (DRD2), nerve growth factor beta (NGF?) and its receptor (NGFR), estrogen receptor alpha (ESR1), beta (ESR2), pituitary tumor transforming gene (PTTG) and metallothionein 3 (MT3). RESULTS: Median DRD2 and NGFR expressions of responsive patients were significantly higher compared to the resistant ones (p= 0.016 and p= 0.009, respectively). Moreover, both expressions were positively correlated with PRL decrease during treatment (r= ?0.66; p= 0.002 and r= 0.57; p= 0.017; respectively). A positive correlation was found between NGFB and DRD2 (r= 0.53; p= 0.023) and PTTG and ESR2 expressions (r= 0.66; p= 0.008). There was also a correlation between serum PRL levels before treatment and ESR2 expression (r= 0.53, p= 0.04). It was not observed correlation between MT3 and responsiveness or resistance to dopamine agonists. CONCLUSIONS: DRD2 and NGFR expressions are related to prolactinoma responsiveness to dopamine agonists whereas PTTG and ESR2 may have a role in tumor aggressiveness. The response of prolactinomas to dopamine agonists should be view as a spectrum ranging from responsive to resistant with tumor growth

M.Sc. (Zoology) / There has been an increasing concern worldwide regarding the possible adverse effects of pharmaceutical supplements present in our aquatic ecosystems and whether or not they modify the physiological functioning in humans and wildlife. Trenbolone acetate (TBA) and zeranol (Z) for example, are two commonly used synthetic anabolic growth promoting hormones in cattle production. TBA is metabolized into trenbolone-β and excreted as both trenbolone-α and -β. In liquid manure trenbolone-β has a half-life of over 270 days and Z, 120 days. Therefore if released into the surrounding environment there is the possibility for long-term severe ecological impacts i.e. fish reproduction and general health. The aim of this study was to determine the physiological effects of several growth promoting hormones used as growth promoting hormones in cattle production on the Mozambique Tilapia – Oreochromis mossambicus. The growth promoting hormones assessed in this study were; Trenbolone acetate, Methyltestosterone, Diethylstilbestrol and Zeranol. The aim was accomplished by making use of histology (gills, liver and gonads) and three biomarker assays; Glutathione-S-transferase (GST), Uridine-Diphosphate Glucuronosyltransferase (UDPGT) and Cellular Energy Allocation (CEA). Stock solutions of Trenbolone acetate (14 μg/l and 15 μg/l), Methyltestosterone (7 μg/l and 7.5 μg/l), Zeranol (2.8 μg/l and 3 μg/l) and Diethylstilbestrol (0.28 μg/l and 0.29 μg/l) were prepared. Fish were exposed under controlled conditions for a period of 24-hours, 4-, 15- and 30-days respectively using a flow-through system. The aquarium water was changed (45 L removed and replaced with 45 L of prepared growth hormone containing bore-hole water) every 48 – 72 hours to remove all waste material thus ensuring the aquariums were clean. Upon performing the necropsies, gills, liver and gonads were removed and examined using standard histological techniques. Muscle tissue was used to determine the CEA, liver and kidney tissue was used for both GST and UDPGT assays. The results obtained from the histology revealed that the gills and liver were not severely affected by exposure to the growth promoting hormones although possible exposure related alterations were evident. The gonads results indicated that exposure to the growth promoting hormones severely affected the morphology and functioning of the organs to the point where reproduction is questionable. The results obtained from the hepatosomatic index (HSI) and gonadosomatic index (GSI) revealed no significant differences (p<0.05) although a trend of increasing HSI and decreasing GSI was evident in the male fish exposed to the androgens. With regards to the biomarker assays there were minor decreases in CEA in the exposed fish but no significant differences (p<0.05) could be established. The GST assay revealed that Zeranol prompted a significant increase (p<0.05) in GST activity in the kidney after 4- and 15-days of exposure while the liver displayed no change in GST activity. The UDPGT assay revealed minor fluctuation in UDPGT activity in both the kidney and liver throughout the study, however, no significant differences (p<0.05) could be established. To conclude, exposure to these growth promoting hormones at the selected concentrations and exposure periods severely compromised the fish’s reproductive capabilities thus challenging the fish’s fitness. Further studies examining the energy metabolism and xenobiotic detoxification pathways of the Mozambique tilapia and other indigenous fish species are recommended to better comprehend the effects that these growth promoting hormones may possess.

Gene therapy is a technique used to inactivate, replace or insert a corrective copy of a defective gene in order to help diseased tissues to function properly. Gene therapy is a promising treatment for many diseases cancer, cystic fibrosis, and Parkinson’s. There are different methods to introduce a gene to the cell; one of them is the use of viruses. Among viruses, lentiviruses have been popular vectors for gene delivery due to their efficient mode of gene delivery. However, the non-specific delivery of genes associated with viruses may result in undesirable side effects. Here, we propose a heterogeneous nanoparticle delivery system for targeted delivery of lentiviral particles containing a therapeutic gene. The heterogeneous nanoparticles (NPs) consist of the low density lipoprotein receptor 3 (LDLR3) and the keratinocyte growth factor (KGF), each fused to elastin-like-polypeptides (ELPs), LDLR3-ELP and KGF-ELP, respectively. Our results show that while homogeneous nanoparticles comprising of LDLR3-ELP alone blocked viral transduction, heterogeneous nanoparticles comprising of KGF-ELP and LDLR3-ELP enhanced viral transduction in cells expressing high levels of the KGF receptors (KGFR) compared to cells expressing low levels of KGF receptors. Overall, this novel design may help with the targeting of specific cells that overexpressed growth factor such as KGFR.