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  • 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.
1

Study of the molecular response of uropathogenic E. coli to ciprofloxacin in human bloodstream infection models to enhance the understanding of antibiotic therapy in urosepsis

Gandi, Senthil Kumar January 2014 (has links)
Urinary tract infection (UTI) is a major burden for healthcare due to high prevalence and increasing multi-drug resistance, and advance to urosepsis which accounts up to 20-30% of sepsis cases. Therapy failures due to inappropriate antibiotic treatment are a serious issue. We are studying the transcriptomic response of the uropathogenic strain E. coli CFT073 to antibiotic treatment during bloodstream infection (BSI) models in order to understand and avoid antibiotic therapy failures in bloodstream infection/urosepsis treatments which are caused by in vivo and in vitro differences of bacterial response to antibiotic challenge which cannot be explained by antibiotic resistance mechanisms. Bloodstream infection models and controls were established by growing E. coli CFT073 in Iso-Sensitest medium, pooled human serum, and pooled human whole blood with and without ciprofloxacin. The minimum inhibitory concentration (MIC) values for E. coli CFT073 in these models were identified and used to set the antibiotic challenge in the serum/blood cultures. The antibiotic challenge was introduced at mid logarithmic phase of growth of the organism to depict a clinical scenario. Global gene expression profiling of these conditions was examined using E. coli Genechip 2.0 from Affymetrix. Data analysis was performed using the Partek Genomics Suite. The difference in the growth medium was well reflected in the growth pattern. In contrast to the growth in IST, the growth in whole blood was double the duration and growth in human serum was 6 fold longer. This difference was also reflected in the transcriptomic study where metabolic genes were regulated differently in each medium as expected. When comparing the responses to antibiotic challenge, bacteria grown in the respective medium displayed specific responses to the antibiotic challenge which were not seen in the other media. The common functions of genes that responded to the ciprofloxacin challenge were SOS response, DNA repair, DNA replication, fimbrial genes and bacteriophage initiation. A subset of the bacteriophage genes showed similar responses between the three models. From genes that were differentially regulated, responses observed in the serum model appeared to have the highest fold changes; this could be an inverse proportion to the nutrient availability in the medium. In this study we have established new models to investigate bloodstream infections based on human serum and whole blood. They have been used to identify previously unknown differences in the molecular response to antibiotic treatment by the uropathogenic E. coli CFT073 depending on the media. In ongoing and future studies we will exploit these differences in gene expression as biomarkers of bacterial response to antibiotics for the development of diagnostic tools for antibiotic therapy monitoring and as well as tools for diagnostics and stratification in drug development.
2

Translational research in rheumatoid arthritis : exploiting melanocortin receptors

Ahmed, Tazeen Jahan January 2013 (has links)
Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting 1% of the population. The aetiology of rheumatoid arthritis is unknown, although there are multiple postulated theories. In 1950, Philip Hench won the Nobel prize for treating patients with rheumatoid arthritis with cortisone. He also treated 6 patients with adrenocorticotropic hormone (ACTH) with good results. ACTH is a melanocortin. The melanocortin system describes the five melanocortin receptors, their ligands, agonists and antagonists and the accessory proteins. The aim of this study was to explore the melanocortin receptors in rheumatoid arthritis synovium. Methods HA-tagged stable cell lines were created for MC1R, MC3R and MC5R. Multiple antibodies were tested for their utility using Western Blot, immunohistochemistry and flow cytometry. Samples of synovium from 28 patients with RA were tested using RTPCR for the presence of MC1R and MC3R. Gene expression was correlated with clinical characteristics, cytokine (RTPCR) expression and immunohistochemical score. Results The stable cell lines expressed MC1R, MC3R and MC5R respectively. Of the antibodies tested none were found to be of utility in detecting MC1R or MC3R .The MC1R RQ values in rheumatoid synovium appear to split into two groups, high and low. The medians of the two groups are significantly different (p=0.0005). There is almost a 5 cycle, or 64 fold, difference in gene expression between the medians of the two groups (1.59 v 6.23). Of note no MC3R positive samples were CD138 high (i.e. no MC3R positive samples had a significant plasma cell infiltrate) (p=0.006). Categorical analysis using Fishers Exact test revealed an association between MC1R high samples and CD68 lining high scores, (i.e. MC1R high samples also had a high macrophage score in the lining of the sample) (p=0.02). MC1R low samples were associated with not being on combination therapy, 15 this did not quite reach significance (p=0.07). Linear regression analysis confirmed these associations for MC1R. PCA analysis did not show any grouping of samples according to any of the variables tested, likely due to sample size. Conclusion MC1R and MC3R are found in human synovium. Current commercial antibodies are not of utility in detecting MC1R or MC3R. Synovial samples can be split into high and low MC1R gene expression groups. MC3R was either present or absent. High expression of MC1R was associated with a high macrophage score and MC3R expression was associated with a low plasma cell score. MC1R and MC3R expression in RA synovium could be used as biomarkers of disease state or severity as well as a target for therapy.
3

Caracterização molecular de tumores de mama triplo-negativos com diferença de expressão de SPARC / Gene expression profiling of triple negative breast tumors with different expression of SPARC identify potential new prognosis biomarkers

Alcantara Filho, Paulo Roberto de 04 September 2017 (has links)
O câncer de mama triplo negativo (TNBC) é um dos tumores mais agressivos, muitas vezes resistentes à terapia sistêmica e com evolução para doença metastática. O entendimento de sua biologia e a concepção de novos tratamentos são essenciais para melhorar o seu prognóstico. Atualmente, as opções de tratamento são reduzidas e a quimioterapia ainda é o tratamento padrão. A expressão de SPARC (secreted protein acidic and rich in cysteine) é supostamente alterada em várias doenças malignas. No entanto, pouco se sabe sobre o valor prognóstico do SPARC em pacientes com TNBC. Usando uma pequena coorte de descoberta de TNBC muito bem caracterizada em relação à expressão do SPARC e comportamento clínico, conseguimos identificar vários genes como diferencialmente expressos na comparação entre amostras de TNBC / SPARC negativo vs. TNBC / SPARC positivo. Cinco desses genes diferencialmente expressos, SOHLH2, DNAJC12, LIM-1, CEACAM-5 e CTAG1A foram escolhidos para serem validados por imuno-histoquímica (IHC) em tissue microarrays (TMAs) contendo uma coorte independente de TNBC. Para acessar o valor prognóstico desses potenciais novos biomarcadores, avaliamos a associação entre a expressão de IHC e os resultados das pacientes pela análise de Kaplan-Meier para a coorte de validação. Foi observado que a coloração negativa da expressão de SOHLH2 e coloração positiva de DNAJC12 e LIM1 mostrou uma tendência a ser correlacionada com um pior prognóstico tanto para a sobrevida livre de doença quanto para sobrevida global. Nossos resultados fornecem novas informações sobre alterações transcriptômicas associadas ao comportamento clínico de TNBC que podem servir como ferramenta potencial para a identificação e caracterização de novos biomarcadores candidatos como fatores prognósticos e preditivos para pacientes com TNBC no futuro / Triple-negative breast cancer (TNBC) is one of the most aggressive, therapy-resistant, and metastatic tumors. Understanding of its biology and designing new treatments are essential to improve its prognosis. Currently, treatment options are reduced, and chemotherapy is still the standard treatment. SPARC (secreted protein acidic and rich in cysteine) expression is reportedly altered in various malignancies. However, little is known regarding the prognostic value of SPARC in TNBC patients. Using a small discovered cohort of TNBC very well characterized regarding SPARC expression status and clinical behavior, we were able to identify several genes as differentially expressed in the comparison between TNBC/SPARC negative vs. TNBC/SPARC positive samples. Five of these differentially expressed genes, SOHLH2, DNAJC12, LIM, CEACAM-5 and CTAG1A were chosen to be validated by immunohistochemistry (IHC) on tissue microarrays (TMAs) containing an independent cohort of TNBC. To access the prognostic value of these potential new biomarkers, we evaluated the association between the IHC expression and patient\'s outcomes by Kaplan-Meier analysis for the validation cohort. We found that negative staining of SOHLH2 expression and positive staining of DNAJC12 and LIM1 showed a trend to be correlated with a poor prognosis for both disease-free survival and overall survival. Our findings provide new information on transcriptome changes associated the clinical behavior of TNBC that may serve as a potential tool for the identification and characterization of new candidate biomarkers as prognostic and predictive factors for patients with TNBC in the future
4

Caracterização molecular de tumores de mama triplo-negativos com diferença de expressão de SPARC / Gene expression profiling of triple negative breast tumors with different expression of SPARC identify potential new prognosis biomarkers

Paulo Roberto de Alcantara Filho 04 September 2017 (has links)
O câncer de mama triplo negativo (TNBC) é um dos tumores mais agressivos, muitas vezes resistentes à terapia sistêmica e com evolução para doença metastática. O entendimento de sua biologia e a concepção de novos tratamentos são essenciais para melhorar o seu prognóstico. Atualmente, as opções de tratamento são reduzidas e a quimioterapia ainda é o tratamento padrão. A expressão de SPARC (secreted protein acidic and rich in cysteine) é supostamente alterada em várias doenças malignas. No entanto, pouco se sabe sobre o valor prognóstico do SPARC em pacientes com TNBC. Usando uma pequena coorte de descoberta de TNBC muito bem caracterizada em relação à expressão do SPARC e comportamento clínico, conseguimos identificar vários genes como diferencialmente expressos na comparação entre amostras de TNBC / SPARC negativo vs. TNBC / SPARC positivo. Cinco desses genes diferencialmente expressos, SOHLH2, DNAJC12, LIM-1, CEACAM-5 e CTAG1A foram escolhidos para serem validados por imuno-histoquímica (IHC) em tissue microarrays (TMAs) contendo uma coorte independente de TNBC. Para acessar o valor prognóstico desses potenciais novos biomarcadores, avaliamos a associação entre a expressão de IHC e os resultados das pacientes pela análise de Kaplan-Meier para a coorte de validação. Foi observado que a coloração negativa da expressão de SOHLH2 e coloração positiva de DNAJC12 e LIM1 mostrou uma tendência a ser correlacionada com um pior prognóstico tanto para a sobrevida livre de doença quanto para sobrevida global. Nossos resultados fornecem novas informações sobre alterações transcriptômicas associadas ao comportamento clínico de TNBC que podem servir como ferramenta potencial para a identificação e caracterização de novos biomarcadores candidatos como fatores prognósticos e preditivos para pacientes com TNBC no futuro / Triple-negative breast cancer (TNBC) is one of the most aggressive, therapy-resistant, and metastatic tumors. Understanding of its biology and designing new treatments are essential to improve its prognosis. Currently, treatment options are reduced, and chemotherapy is still the standard treatment. SPARC (secreted protein acidic and rich in cysteine) expression is reportedly altered in various malignancies. However, little is known regarding the prognostic value of SPARC in TNBC patients. Using a small discovered cohort of TNBC very well characterized regarding SPARC expression status and clinical behavior, we were able to identify several genes as differentially expressed in the comparison between TNBC/SPARC negative vs. TNBC/SPARC positive samples. Five of these differentially expressed genes, SOHLH2, DNAJC12, LIM, CEACAM-5 and CTAG1A were chosen to be validated by immunohistochemistry (IHC) on tissue microarrays (TMAs) containing an independent cohort of TNBC. To access the prognostic value of these potential new biomarkers, we evaluated the association between the IHC expression and patient\'s outcomes by Kaplan-Meier analysis for the validation cohort. We found that negative staining of SOHLH2 expression and positive staining of DNAJC12 and LIM1 showed a trend to be correlated with a poor prognosis for both disease-free survival and overall survival. Our findings provide new information on transcriptome changes associated the clinical behavior of TNBC that may serve as a potential tool for the identification and characterization of new candidate biomarkers as prognostic and predictive factors for patients with TNBC in the future

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