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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.
151

Análise das dosagens do fator de crescimento endotelial vascular no plasma e fluidos peritoneais de pacientes com câncer epitelial de ovário / Analysis of measurements of vascular endothelial growth factor in plasma and peritoneal fluids of patients with epithelial ovarian cancer

Solange Maria Diniz Bizzo 29 January 2010 (has links)
A carcinogênese epitelial ovariana tem sido foco de estudos científicos em todo o mundo desenvolvido. A angiogênese tumoral ovariana é um processo multifatorial que resulta em vários produtos pró-angiogênicos. Entre eles, o fator de crescimento vascular endotelial (VEGF) é predominante. Os objetivos deste estudo foram relacionar as dosagens do VEGF dos fluidos peritoneais, do plasma periférico e do infundíbulo pélvico aos níveis de citorredução em pacientes operadas de adenocarcinoma epitelial de ovário (CEO); formular um modelo probabilístico de citorredução e utilizar estas dosagens para estimar a probabilidade do desfecho de citorredução. Além disto, foi criada uma nova variável chamada carga de VEGF. Pelo procedimento step-wise a citorredução foi melhor descrita pela carga de VEGF, mas faltou Normalidade aos resíduos, não sendo possível a adequação de um modelo matemático. Porém, a curva ROC, forneceu uma área sob a curva de 0,84, com sensibilidade de 71,4 % e especificidade variando de 69,5 a 73,9%. O ponto de corte ótimo foi 15,52 log de picograma de carga de VEGF. A odds-ratio (OR) calculada para citorredução ótima descrita pela carga de VEGF foi de 11 (IC= 2,59 ; 46,78). No grupo com estágio avançado (III e IV), a OR foi de 6 (IC= 1,15; 31,22). Apesar do pequeno número de casos, esta nova variável pode vir a ser um auxiliar na determinação de situações onde cirurgia citorredutora deixa de ser a pedra fundamental do tratamento primário do CEO e a indução quimioterápica passe a ter o principal papel na citorredução química antes da cirugia nestes casos. / Epithelial ovarian carcinogenesis has been the focus of scientific studies in developed world. The ovarian tumor angiogenesis is a multifactorial process that results in pro-angiogenic products. Among them, vascular endothelial growth factor (VEGF) is predominant. This study aimed to relate VEGF levels in peritoneal fluids, peripheric plasma and pelvic infundibular plasma to debulking levels in patients operated on for epithelial ovarian carcinoma (EOC), formulate a probabilistic model for debulking and use these measurements to estimate the probability of the outcome of debulking. Moreover, it was created a new variable called burden of VEGF. For step-wise procedure, cytoreduction was better described by of burden VEGF, but missed Normality of residuals, so the adequacy of a mathematical model was not possible. Nevertheless, the ROC curve provided an area under the curve of 0.84, with sensitivity of 71.4 % and especificity varying from 69.5 to 73,9%. The optimal cutoff point was 15.52 log of picograms of VEGF burden. An odds-ratio for optimal cytoreduction described by the VEGF burden was 11 (CI= 2.59; 46.78). In the group with advanced stages (III & IV), the OR was 6 (CI= 1.15; 31.22). Apart from the small number of cases, this new variable might help to determine situations where cytoreductive surgery leaves behind the cornerstone of primary treatment of CEO and the chemotherapic induction comes to have main role in chemical cytoreduction prior to surgery in these cases.
152

Produção de VEGF e HIF-1? em pacientes com carcinoma de mama localmente avançado submetidas à quimioterapia neoadjuvante. / Production of VEGF and HIF-1? in patients with locally advanced breast cancer primarily submitted to neoadjuvant chemotherapy.

Garieri, Alexandre Pavan 09 May 2008 (has links)
Determinar o valor prognóstico e preditivo do VEGF (vascular endothelial growth factor) e do HIF-1? (Hypoxia-inducible factor-1) em relação à sobrevida livre de doença (SLD) e sobrevida global (SG) em pacientes com carcinoma de mama localmente avançado (CMLA) tratadas primariamente pela quimioterapia neoadjuvante. MATERIAIS E METODOS: VEGF e HIF foram quantificados consecutivamente em plasma de 36 pacientes com CMLA pelo método de ELISA (enzyme labeling immunoassay absorbant) para o VEGF165 e o HIF-1?. O tratamento neoadjuvante foi realizado em todas as pacientes com docetaxel e epirrubicina. O tempo médio de seguimento foi de 56 meses. RESULTADOS: Uma análise univariada demonstrou que o HIF-1? está significantemente relacionado à SLD (P =.0238) e à SG (P = .0121) com as pacientes HER-2 positivas. Não houve diferença significante para a SLD ou SG no que diz respeito aos receptores de hormônio, comprometimento axilar ou grau tumoral. Os valores de VEGF foram maiores no grupo de pacientes RE+ do que no grupo RE negativo (P =.01). Inversamente os valores de HIF-1? foram menores no grupo RE+ comparados ao grupo RE - (P =.02). Pacientes com recorrência óssea apresentaram uma tendência a apresentarem valores de VEGF menores (media, 175.7 pg/ml) do que aquelas com recorrência visceral (441 pg/ml). Uma análise multivariada demonstrou o comprometimento axilar (P =.0004), receptores de estrógeno (ER) (P < .0001), e tamanho do tumor (P = .0085) como fatores independentes de SLD. O HIF-1? foi tido como um fator independente preditivo de SG (P =.0180). Não houve diferença estatisticamente significante entre os valores plasmáticos de HIF-1? ou VEGF nos períodos pré e pós quimioterapia. CONCLUSÕES: Os resultados sugerem que o nível plasmático do HIF-1? é preditivo de SLD e SG nas pacientes com CMLA apresentando uma sobreposição as pacientes HER-2 positivas. As dosagens de VEGF podem ser preditivas de resposta e prognóstico no tratamento neoadjuvante, mas são necessários novos estudos prospectivos comparados ao HIF-1? para conclusões mais consistentes. / To determine the predictive and prognostic value of vascular endothelial growth factor (VEGF) and Hypoxia-inducible factor-1 (HIF-1?) for relapse-free survival (RFS) and overall survival (OS) in locally advanced breast cancer (LABC) primarily submitted to neoadjuvant chemotherapy. MATERIALS AND METHODS: VEGF and HIF were quantitatively measured in plasma sample from 36 consecutive patients with LABC using an enzyme immunoassay for human VEGF165 and HIF-1?. Neoadjuvant treatment was given to all patients as docetaxel and epirrubicin. The follow-up median time was 56 months. RESULTS: Univariate analysis showed that HIF-1? is a significant predictor of RFS ( P = .0238) and OS (P = 0121) in HER-2 positive patients. No significant difference was seen in RFS or OS related to hormonal receptor, axillary status or tumoral grade. The VEGF level was higher in the group of patients who ER was positive than ER negative (P = .01). On the other hand, the HIF-1? level is higher in ER negative patients than ER positive ( P=.02). Patients with bone recurrences tended to have lower VEGF plasma level (median, 175.7 pg/ml) than patients with visceral metastasis (441 pg/ml). Multivariate analysis showed nodal status (P = .0004), estrogen receptor (ER) status (P < .0001), and tumor size (P = .0085) to be independent predictors of RFS. HIF-1? was found to be an independent predictor of OS (P = .0180). No statistically differences were observed related to pre and post chemotherapy period in HIF-1? or VEGF measurements. CONCLUSION: The results suggest that high level of plasma HIF-1? is associated to HER-2 over expression and they are major predictive factors of RFS and OS in LABC. VEGF content might also predict outcome after neoadjuvant treatment, however further studies in a prospective setting with HIF-1? homologous treatments are required.
153

Avaliação da transferência gênica por vetor viral na glândula lacrimal e resposta na neovascularização corneana / Evaluation of gene transfer by viral vector in the lacrimal gland and response to corneal neovascularization

Nominato, Luís Fernando Resende da Silva 27 October 2017 (has links)
Objetivos: Os objetivos deste estudo foram: 1) determinar a eficácia da transferência gênica do vetor de adenovírus sorotipo 5, carreando o gene do receptor do fator de crescimento endotelial vascular (VEGF) solúvel humano (sVEGFR1) para a glândula lacrimal (GL); 2) investigar se a expressão de sVEGFR1 interfere na neovascularização da córnea (NVC), induzida por queimadura alcalina; 3) avaliar a segurança do procedimento. Métodos: Trinta e dois ratos Wistar foram submetidos à queimadura central da córnea direita com solução de hidróxido de sódio (NaOH) 1 M. Os animais foram divididos em três grupos e injetados diretamente em sua GL direita 25 ?l de vetores virais AdVEGFR1 (1x1010 pfu) (12 animais), 25 ?l do vetor AdNull (1x1010pfu) (10 animais), ou 25 ?l de solução salina (Controle). Após sete dias, a NVC foi observada e fotografada na lâmpada de fenda. A secreção lacrimal foi medida com fenol. A presença do sVEGFR1 na GL foi testada por qPCR (quantitative polymerase chain reaction) e a coloração, por imunofluorescência. O qPCR foi também utilizado para comparar o RNA mensageiro (RNAm) de ilterleucina-1beta (IL-1?), ilterleucina-6 (IL-6) e fator de necrose tumoral alfa (TNF-?) na GL e no gânglio do trigêmeo (GT). Resultados: O vetor AdVEGFR1 transfectou 83% dos ratos. O sVEGFR1 estava presente nas células acinares da GL. A NVC foi prevenida em nove de doze animais do grupo AdVEGFR1, em comparação com o grupo Ad-Null (3:10) e o grupo Controle (1:10) (p=0,0317). A secreção lacrimal e o RNAm das citocinas na GL e no GT foram semelhantes nos três grupos (p>0,05). Conclusões: A transferência gênica do vetor adenoviral para a GL demonstrou expressão local do sVEGFR1 humano, e evitou a NVC na maioria dos olhos expostos a queimaduras alcalinas, se mostrando seguro para a estrutura e função da GL. / Purpose: The aims of this study were: 1) to determine the efficacy of adenovirus vector serotype 5 (Ad) encoding human soluble VEGF receptor 1 (sVEGFR1) gene transfer to the lacrimal gland (LG); 2) to investigate whether expression of sVEGFR1 acts in corneal neovascularization (CNV), induced by alkali burn and; 3) to evaluate the safety of the procedure. Methods: AdVEGFR1viral vectors (25 ?l, 1x1010pfu) were injected in the right LG of rats and compared with AdNull vector (25 ?l, 1x1010pfu) or 25?l saline (Control) before cornea alkali burn with 1 M NaOH. After seven days, CNV was observed and photographed in the slit lamp. Tear secretion was measured with phenol red thread. The animals were tested for human VEGFR1 mRNA and protein in the LG by qPCR and immunofluorescence staining, respectively. qPCR was also used to compare the mRNA of IL-1?, IL-6, and TNF-? in LG and ipsilateral trigeminal ganglion (TG). Results: Ad-VEGFR1 transfected 83% of the rats. VEGFR1 was present in LG acinar cells. CNV was prevented in 9 of 12 animals of Ad-VEGFR1 group, compared to Ad-Null (3:10) and Control (1:10) (p=0.0317). The tear secretion and the cytokines mRNA in LG and TG were similar all three groups (p>0.05). Conclusion: Adenoviral vector gene transfer to LG as the has shown local expression of human sVEGFR1, as It prevented CNV in most of the eyes exposed to alkali burn and was safe for LG structure and function.
154

Régulateurs traductionnels de l'expression génique de la différenciation et du stress cellulaire / Translational regulation during the differentiation and cellular stress

Hantelys, Fransky 20 February 2017 (has links)
La cellule est susceptible de modifier l'expression de ces gènes en fonction de son environnement. Dans les cellules eucaryotes, la régulation de l'expression de ces gènes se présente dans plusieurs étapes. Cette régulation peut intervenir dès la transcription de l'ADN jusqu'au devenir des transcrits. La régulation post-transcriptionnelle tient un rôle déterminant dans la synthèse protéique. Elle regroupe l'ensemble des contrôles qui s'exercent sur les transcrits. Cette régulation est induite en réponse à différents stimuli comme la différenciation ou lors de stress cellulaires. En situation de stress, la traduction canonique dépendante de la coiffe est bloquée, à l'exception de certains ARNm essentiels pour assurer la survie des cellules. De ce fait, les cellules mettent en place un mécanisme alternatif afin de continuer la traduction. Un des mécanismes de traduction, implique le site d'entrée interne du ribosome ou IRES (Internal Ribosome Entry Site). L'IRES est une séquence en structure secondaire dans la partie 5' non-traduite de certains ARNm. Il existe des facteurs responsables de leur activation appelés ITAF ou IRES-transacting factor, permettant le recrutement des ribosomes pour initier la traduction. Les protéines pouvant se lier aux ARN sont les acteurs majeurs de l'activation des IRES. Mon travail de thèse est d'étudier les régulateurs post-transcriptionnels en réponse à différents stimuli par le biais de la traduction IRES-dépendante. Dans la première partie de mon projet, nous avons montré la régulation de la traduction via l'activation de l'IRES du FGF1 et ce de manière promoteur-dépendante au cours de la différenciation des myoblastes. Grâce à la technique de résonance plasmonique de surface (SPR) nous avons découvert deux protéines p54nrb/NONO et hnRNPM en tant qu'ITAF capables de former un complexe pour activer l'IRES du FGF1 durant la différenciation des myoblastes. Dans la deuxième partie de ma thèse, nous avons démontré l'existence de l'IRES du VEGFD durant un choc thermique dans les cellules cancéreuses. Nous avons aussi découvert que cette activation est médiée par un ITAF qui est la nucléoline, jamais démontrée auparavant comme ITAF de l'IRES du VEGFD. D'après nos résultats, le stress thermique induit la délocalisation de la nucléoline du noyau vers le cytoplasme pour changer la conformation de l'IRES du VEGFD afin de continuer sa traduction. Dans la troisième partie de mon projet, j'ai étudié de manière générale la régulation des gènes angiogéniques et lymphangiogéniques. L'ensemble des données montre que ces gènes sont majoritairement régulés au niveau traductionnel dans les cardiomyocytes en condition hypoxique. En étudiant les IRES angiogéniques et lymphangiogéniques, nos résultats montrent l'activation de ces IRES à différents temps au cours de l'hypoxie précoce. Dans la même condition, nous avons découvert la protéine vasohibin-1 comme ITAF hypoxique et spécifique de l'IRES du FGF1 dans les cardiomyocytes. En conclusion, nous avons découvert différents ITAF spécifiques à un IRES et en fonction du stress. P54nrb/NONO, hnRNPM sont des ITAF de l'IRES du FGF1 durant la différenciation cellulaire et la vasohibine-1 en hypoxie dans les cardiomyocytes. La nucléoline permet d'activer un IRES du VEGFD en réponse au choc thermique. / In cell, gene expression can be modified depending on the cellular microenvironment. Regulation of gene expression occurs at different levels, ranging from the transcription of the DNA to the mRNA. Among the post- transcriptional regulation, the control of translation plays a crucial role. In particular, the translational regulation occurs in response to different stimuli such as cell differentiation or cell stress. In stress condition, the canonical cap-dependent translation is blocked, excepted some mRNAs that are translated by alternative mechanisms. One of these mechanisms involves the structural elements of the mRNAs, the IRES (Internal Ribosome Entry Sites). The IRES activation involves some factors called ITAFs (IRES trans-acting factors), which allow the internal recruitement of ribosomes to initiate translation. My thesis is to study the mechanisms of IRES-dependent translation regulation in response to different stimuli, and to identify ITAFs responsible for this regulation. In the first part of my project, we have shown that the translation controlled by the FGF1 mRNA IRES is activated. This activation depends on its own promoter during the early phase of murine myoblast differentiation. Through biomolecular interaction analysis technology by surface plasmon resonance coupled to mass spectrometry (BIA/MS), we identified two proteins, p54nrb/NONO and hnRNPM bound both to the IRES and the FGF1gene promoter. These two proteins are both ITAFs activators of IRES and activators of FGF1 promoter transcription, resulting in a coupling of transcription and translation responsible for the induction of the FGF1 expression during myoblast differentiation. In the second part of this thesis, we demonstrated the existence of an IRES within the VEGFD mRNA. This IRES is activated by heat shock in mammary murine carcinoma. BIA/MS technology has enabled us to identify nucleolin as ITAF responsible for this activation. SHAPE experiments revealed the presence of two alternative structures of VEGFD IRES. According to our results, the heat shock induced the relocation of nucleolin from the nucleus to the cytoplasm, suggesting its binding to the mRNA in the cytoplasm could stabilize the conformation of the mRNA VEGFD IRES and activate its translation. The third part of my thesis focused on translational regulation of lymphangiogenic and angiogenic genes into cardiomyocytes in hypoxic conditions. The data obtained by the semi-global approach Fluidigm indicate that only few genes are induced at the transcriptional level, while the majority of them, especially those which have the mRNA IRES, are activated at translational level in hypoxic cardiomyocytes. I have also shown that the mRNA IRES of factors (lymph)angiogenic VEGF and FGF are activated during early hypoxia. Through Technology BIA/MS, I identified a specific hypoxic ITAF of FGF1 IRES in cardiomyocytes: it is the vasohibin - 1 protein involved in angiogenesis and stress tolerance. So, my thesis has enabled to make progress in understanding the mechanisms of IRES-dependent translation regulation. In addition, I have demonstrated that in cardiomyocytes during hypoxia the gene expression is surprisingly regulated at translational level. My work led to the identification of several molecular actors responsible for the regulation of mRNA (lymph)angiogenic factors translation, which could play a key role in ischemic pathologies and in cancer, and provide new targets therapeutic.
155

Mécanismes de l'angiogenèse associée aux tumeurs endocrine digestives : rôle du VEGF / Mechanisms of angiogenesis associated with digestive endocrine tumors : role of VEGF

Villaume, Karine 28 October 2009 (has links)
Les tumeurs endocrines digestives sont des tumeurs hypervasculaires, ce qui suggère l'existence d'un processus d'angiogenèse tumorale actif. Les mécanismes de l'angiogenèse tumorale associée aux tumeurs endocrines digestives sont complexes. Deux processus semblent coexister : les tumeurs les mieux différenciées sont capables de récapituler les propriétés pro-angiogéniques des cellules endocrines normales alors que les tumeurs moins différenciées et plus agressives sont associées à un processus d angiogenèse non spécifique, développé en réponse à l'hypoxie. Dans ces deux processus, le VEGF joue vraisemblablement un rôle important, dans la mesure où il fait partie intégrante du programme de différenciation endocrine. L'objectif de notre travail a été de mieux comprendre les mécanismes de sa régulation dans les cellules endocrines digestives tumorales et d'analyser son rôle dans la croissance tumorale, à travers une double approche expérimentale, in vitro et in vivo ; Nos résultats nous ont permis de : (a) montrer la complexité de la régulation de la synthèse et de la sécrétion du VEGF par les cellules endocrines néoplasiques, qui implique plusieurs voies de signalisation (PI3K/Akt/mTOR et p38/MAPK), dont les rôles respectifs varient selon le type de cellule étudiée ; (b) confirmer expérimentalement la dissociation entre expression du VEGF et capacités angiogéniques d'une part, propriétés invasives et métastatiques d'autre part ; (c) montrer expérimentalement que l'inhibition de l'angiogenèse peut contribuer à l'effet antitumoral de substances d'intérêt thérapeutique dans les tumeurs endocrines digestives / Digestive endocrine tumors are hypervascular tumors, likely to be associated with an active angiogenic process. The mechanisms of tumor angiogenesis in digestive endocrine tumors are complex. Two processes seem to coexist: well differentiated tumors are able to recapitulate the pro-angiogenic capacities of normal endocrine cells whereas less differentiated and more aggressive tumors are associated with a non specific angiogenic process, in response to hypoxia. In both processes, VEGF is likely to play an important role, since it is constitutively expressed by normal peptide-secreting endocrine cells, as part of their specific differentiation program. Our aim was to evaluate the mechanisms of regulation of VEGF synthesis and secretion by neoplastic digestive endocrine tumors and to analyze its role in tumor progression, through an in vitro and in vivo experimental approach. We were able to demonstrate that: (a) the regulation of VEGF synthesis and secretion is complex and involves several pathways (PI3K/Akt/mTOR and p38/MAPK), with different roles according to the cell studied; (b) there is a dissociation between VEGF expression and angiogenic capacities, on one hand, and invasive and metastatic properties, on the other hand; (c) the inhibition of angiogenesis may contribute to the anti-tumoral effect of several drugs of therapeutic interest in digestive endocrine tumors
156

Small Interfering RNA Decreases VEGF mRNA Expression and Proliferation of Colorectal Cancer Cells

Ward, Stephen 15 November 2006 (has links)
Vascular endothelial growth factor (VEGF-A) was first described in 1989 for its angiogenic and mitogenic properties. Early studies indicated that VEGF-A acts primarily in a paracrine pathway which is limited to vascular endothelium. Further investigation showed that VEGF-A and VEGF receptor-2 (VEGFR-2) are expressed by many solid tumors and improve cell growth and survival. Therefore, VEGF-A may act via an autocrine pathway that effects tumor cellular proliferation by binding VEGFR-2 at the cell surface. This study utilizes small interfering RNA (siRNA) technology to investigate the presence of an autocrine loop in human RKO colorectal cancer cells. RT-PCR demonstrated the expression of VEGF-A, VEGF-B, VEGF-D, placental growth factor (PlGF), VEGFR-2, neuropilin-1 (NP-1) and neuropilin-2 (NP-2) in vitro by RKO cells. Transfection with siRNA against VEGF-A resulted in a 94% knockdown of VEGF-A expression by ELISA. Northern blot, quantitative real time PCR and semiquantitative RT-PCR confirmed the knockdown data. In addition, transfected RKO cells showed a 67% decrease in cellular proliferation by WST-1 assay. This data correlated to the ELISA results. In summary, the presence of VEGF-A and VEGFR-2 argues in favor of an autocrine loop in human colorectal cancer cells. siRNA targeting of VEGF-A remains a promising anti-tumor therapeutic strategy.
157

Erhebung über mögliche kardiovaskuläre Nebenwirkungen nach intravitrealer Injektion der VEGF-Inhibitoren Bevacizumab und Ranibizumab bei altersbedingter Makuladegeneration / Investigation about possible cardiovascular adverse events after intravitreal application of VEGF-inhibitors bevacizumab and ranibizumab in therapy of age-related maculopathy

Schäfer, Kristine 18 April 2012 (has links)
No description available.
158

Zytokinabhängige Expression von EGF und VEGF und ihrer Rezeptoren EGFR und VEGFR-1 im Tumormikromilieu des kolorektalen Karzinoms / Cytokine-dependent gene expression of EGF, VEGF and their receptors EGFR and VEGFR-1 in the microenvironment of colorectal carcinoma

Sattler, Florentine 08 July 2014 (has links)
No description available.
159

Le phénotype mésenchymateux et la réponse aux agents anti-VEGF dans le cancer colorectal / The mesenchymal phenotype and the response to VEGF-targeted agents in colorectal cancer

Bouygues, Anaïs 12 December 2017 (has links)
Le VEGF est une cible validée pour le traitement du cancer colorectal métastatique avec le bevacizumab (Avastin) et l’aflibercept (Zaltrap) qui sont approuvés en première ligne et seconde ligne de traitement. Malgré les efforts intenses, il n’existe pas de biomarqueurs prédictifs pour identifier les patients qui pourraient répondre ou non aux therapies anti-VEGF. Récemment, différents sous-groupes de cancers colorectaux ont été identifies se basant sur l’expression de genes, incluant le groupe CMS4, un sous-groupe de phénotype mésenchymateux, angiogénique et de mauvais prognostic. Nous voulons établir si le phenotype mésenchymateux est prédictif pour la réponse aux agents anti-VEGF. Les cellules de cancer colorectal ont été étudiées in vitro et in vivo pour l’expression des marqueurs épithéliaux (E-cadherine, gamma-catenine, cytokeratine 18) et mésenchymateux (vimentine, N-cadherine, fibronectine) par qRT-PCR and western-blot et leur distribution par E-cadherine et beta-catenine pour immunocytochimie. Cinq modèles de cancer colorectal ont été rangés selon un phénotype épithélial prononcé (HT-29 et DLD-1), intermédiaire (HCT-116) à mésenchymateux (HCT-116/5-FU, LS174T) et les capacités d’inhibition de la croissance par le bevacizumab et l’aflibercept ont été établi. La sécrétion de VEGF a été déterminé par ELISA et la densité microvasculaire a été caractérisé par immunohistochimie quantitative. Le phénotype mésenchymateux est associé à une grande densité vasculaire mais pas aux ligands VEGF. Deux modèles de xénogreffes (DLD-1, HCT-116/5-FU) sont sensibles au bevacizumab et à l’aflibercept, deux modèles sont plus sensibles à l’aflibercept qu’au bevacizumab et un modèle est résistant aux deux molécules. L’aflibercept est plus efficace que le bevacizumab sur l’ensemble des modèles. Le phénotype mésenchymateux n’est pas prédictif pour la réponse aux agents ciblant le VEGF, ni positivement, ni négativement. / VEGF is a validated target for treatment of metastatic colorectal cancer (mCRC) with bevacizumab (avastin) and aflibercept (zaltrap) being approved for first and second line treatment, respectively. Despite intense efforts, no predictive biomarkers are available to identify patients likely to respond, or not, to VEGF-targeted therapies. Recently, different subtypes of CRC have been identified based on gene expression analysis including CMS4, a molecular subgroup with a mesenchymal phenotype, prominent angiogenesis and poor prognosis. We here wish to establish if the mesenchymal phenotype is predictive for the response to VEGF-targeted agents. CRC cell lines were examined for expression of epithelial (E-cadherin, gamma-catenin, cytokeratin 18) and mesenchymal (vimentin, N-cadherin, fibronectin) markers in vitro and in vivo by qRT-PCR and Western blot analysis and for the cellular distribution of E-cadherin and beta-catenin by ICC. Five CRC models were selected ranging from pronounced epithelial (HT-29, DLD-1), intermediate (HCT-116) to mesenchymal (HCT-116/5-FU, LS174T) and the tumor growth inhibitory activity of bevacizumab and aflibercept was established. VEGF-secretion was determined by ELISA and the microvascular density was characterized by quantitative IHC analysis. The mesenchymal phenotype was associated with higher microvascular density, but not with the expression of VEGF ligands. Two CRC xenograft models (DLD-1, HCT-116/5-FU) were sensitive to both bevacizumab and aflibercept, two models were more sensitive to aflibercept, compared to bevacizumab (HT-29, HCT-116), and one model (LS174T) was resistant to both agents. Aflibercept was more potent than bevacizumab in all CRC models. The mesenchymal phenotype was not predictive for the response to VEGF-targeted agents, neither positively nor negatively.
160

Caracterização histopatológica e imunoistoquímica de bexigas de bovinos com hematúra enzoótica

Silva, Maria Aparecida da 27 February 2012 (has links)
Made available in DSpace on 2016-12-23T13:53:40Z (GMT). No. of bitstreams: 1 Maria Aparecida da Silva.pdf: 3366725 bytes, checksum: 59d418ef608b4e75da9a6ba6a1fdb233 (MD5) Previous issue date: 2012-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Bovine enzootic hematuria (BEH) is caused by chronic ingestion of Pteridium aquilinum and is characterized by the presence of blood in the urine and development of lesions in the urinary bladder and is responsible for economic losses. Poisoning by this plant can also occur in humans. The objective was to evaluate the lesions in bladders of animals with BEH in the south region of the Espírito Santo. For this, were evaluated 350 bladders of bovines in a slaughterhouse and, of these, selected 46 that had macroscopic lesions and/or hematuria. Samples of each bladder were fixed in formalin 10% submitted to histological processing and classified by histomorphology. The immunohistochemistry was performed with anti-vimentin, anti-cytokeratin, anti-CD31, anti-VEGF and anti-uroplakin only in the 26 bladders that presented neoplastic lesions. Non-neoplastic lesions were observed in 100% of samples and the neoplastic in 56.52%. The presence of tumors was significant (p<0.05) in the caudal portion of the bladder. Detected neoplastic types were urothelial carcinoma, in situ carcinoma, adenocarcinoma, hemangioma, myxoma and hemangiosarcoma. There was a higher frequency of dysplasia, clear cell metaplasia, inflammation and vascular thickening in bladders with neoplasm. The expression of cytokeratin was significant (p<0.05) in epithelial neoplasms and vimentin in mesenchymal neoplasms. Uroplakin III differed in varied types of neoplastic lesions and showed to be typical and atypical while that of CD31 was significantly (p <0.05) in vascular mesenchymal neoplasms. A significant difference (p <0.05) in the number of vessels extratumorais stained by VEGF between myxomas and adenocarcinomas, and in intratumoral vessels stained by CD31 and VEGF in the different tumor types. Positive correlation existed between the number of intra- and extratumoral vessels in hemangiomas, hemangiosarcomas, and myxomas stained by CD31; between hemangiomas, myxomas, and adenocarcinomas stained with VEGF; between the expression of vimentin and CD31 and between cytokeratin and uroplakin. It is concluded that bladders from bovines with BEH have non-neoplastic and neoplastic lesions, isolated or associated. Biomarkers aid in the differentiation of the histogenesis of epithelial and vascular mesenchymal neoplasms. Uroplakin demonstrated to be effective for the assessment of integrity urothelial, and vascular markers (CD31 and VEGF) for endothelial integrity and for prognosis / A hematúria enzoótica bovina (HEB) é causada pela ingestão crônica de Pteridium aquilinum e caracteriza-se pela presença de sangue na urina e desenvolvimento de lesões na bexiga, sendo responsável por grandes perdas econômicas. A intoxicação por esta planta também pode ocorrer em humanos. Objetivou-se avaliar lesões de bexigas de animais com HEB na região sul do Espírito Santo. Para isto, foram avaliadas 350 bexigas de bovinos em matadouro frigorífico e, destas, selecionadas 46 que apresentavam lesões macroscópicas e/ou hematúria. Amostras de cada bexiga foram fixadas em formol a 10% submetidas ao processamento histológico de rotina e classificadas histomorfologicamente. A imunoistoquímica foi realizada com anti-vimentina, anti-citoqueratina, anti-CD31, anti-VEGF e anti-uroplaquina apenas nas 26 bexigas que revelaram neoplasia. Lesões não neoplásicas foram observadas em 100% das amostras e neoplásicas em 56,52%. A presença de neoplasias foi significativa (p<0,05) na porção caudal da bexiga. As neoplasias encontradas foram carcinoma urotelial; carcinoma in situ, adenocarcinoma, hemangioma, mixoma e hemangiossarcoma. Houve maior frequência de displasia, metaplasia de células claras, inflamação e espessamento vascular em bexigas com neoplasia. A expressão de citoqueratina foi significativa (p<0,05) nas neoplasias epiteliais e vimentina nas mesenquimais. A marcação da uroplaquina III diferiu nos diversos tipos neoplásicos e revelou-se típica e atípica enquanto que a do CD31 foi significativa (p<0,05) nas neoplasias mesenquimais vasculares. Houve diferença significativa (p<0,05) na quantidade de vasos extratumorais marcados pelo VEGF entre os mixomas e adenocarcinomas e nos vasos intratumorais marcados por CD31 e VEGF nos diferentes tipos tumorais. Houve correlação positiva entre os vasos extra e intratumorais nos hemangiomas, hemangiossarcomas e mixomas marcados pelo CD31; nos hemangiomas, mixomas e adenocarcinomas marcados pelo VEGF; entre a expressão de vimentina e CD31 e entre citoqueratina e uroplaquina. Conclui-se que bexigas de bovinos com HEB apresentam lesões não neoplásicas e neoplásicas, isoladas ou associadas. Os biomarcadores auxiliam na diferenciação da histogênese das neoplasias epiteliais e mesenquimais vasculares. Uroplaquina demonstrou-se efetiva para a avaliação da integridade urotelial e os marcadores vasculares (CD31 e VEGF) para a integridade endotelial e para o prognóstico

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