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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.
131

Comparação de resultados de uma coorte sob as abordagens prospectiva e histórica: amamentação no primeiro ano de vida / Comparison between results of a cohort under prospective and historical approaches: breastfeeding in the first year of age

Alencar, Gizelton Pereira 23 May 2003 (has links)
Objetivo. Uma coorte de crianças foi observada sob duas abordagens: coorte prospectiva e coorte retrospectiva (histórica) e o objetivo foi comparar as estimativas da função de riscos do modelo de Cox entre as duas abordagens e a mesma comparação com o modelo complemento log-log. Além disso, comparar as estimativas da função de riscos pelos modelos de Cox e complemento log-log para cada uma das abordagens, separadamente. Métodos. Quando se estuda o tempo de sobrevida da amamentação sem as covariáveis, foram obtidas as estimativas pela técnica atuarial e modelo complemento log-log da informação retrospectiva e a técnica de Kaplan-Meier para a informação prospectiva. Os modelos de Cox e complemento log-log foram utilizados para estimar a razão de riscos (HR) com covariáveis para as duas abordagens. Resultados. Sem as covariáveis, a comparação entre as duas abordagens mostrou que as estimativas de S(t) pela informação retrospectiva estão um pouco defasadas em relação à medida prospectiva. Com as covariáveis, os resultados dos modelos de Cox e complemento log-log são semelhantes tanto para os dados prospectivos quanto para os retrospectivos. Foram semelhantes, também, os resultados de um mesmo modelo para cada uma das fontes de informação. Conclusões. Em geral, as estimativas foram bastante próximas em quaisquer das comparações. Somente a variável hábito de fumar da mãe durante a gravidez permaneceu nos modelos finais para todas as técnicas utilizadas, com estimativas próximas, reforçando semelhança entre as várias abordagens. / Objective. A cohort of children was observed under two approaches: prospective cohort and retrospective (historical) cohort and the objective was to compare the estimates of the hazard ratio from Cox model between the two approaches and do the same comparison using the complementary log-log model. Moreover, to compare the estimates of the hazard ratio from the two models to each one of the approaches, separately. Methods. When the survival time for breastfeeding is studied without the covariates, the comparison between the results of actuarial technique and the complementary log-log model has been made for the recorded information. The Kaplan-Meier technique has been used with the daily notebook measures. The Cox and complementary log-log models can estimate the risk rate of covariates categories to both approaches. Results. Without the covariates, the comparison between the two information resources showed that retrospective measures give lower estimates than that from the prospective measures. With covariates, the estimates are not so different and led to the same results. Conclusions. The estimates of each one of the comparisons were too close. Just the variable mothers smoking during the pregnancy stayed in the final models for every techniques used, with close estimates, reinforcing likeness between the several approaches.
132

Análise de fatores inflamatórios na discinesia induzida por L-DOPA em modelo de camundongos: caracterização da enzima ciclooxigenase-2 / Analysis of inflammatory factors in L-DOPA-induced dyskinesia in a mouse model: characterization of the enzyme cyclooxygenase 2

Pereira, Maurício dos Santos 27 October 2017 (has links)
A doença de Parkinson (DP) é a segunda doença neurodegenerativa que mais atinge a população mundial. O desenvolvimento dos prejuízos motores decorrentes da doença está relacionado a sua fisiopatologia, que promove principalmente a neurodegeneração dos neurônios dopaminérgicos da substância negra pars compacta. Estudos sugerem o envolvimento de vias inflamatórias exacerbando a morte celular na fisiopatologia da DP. O fenômeno neuroinflamatório é caracterizado pela ativação de diversas células do sistema nervoso central, como neurônios, micróglia e astrócitos, além dos principais mediadores pró- inflamatórios, que são a enzima ciclooxigenase-2 (COX-2), o fator de necrose tumoral-alfa (TNF-?), a interleucina 1? (IL-1?) e a interleucina 6 (IL-6), entre outros. Estes fatores estão presentes em estruturas neuroanatômicas como o estriado e substância negra pars compacta de indivíduos com a DP. O tratamento crônico com L-DOPA, o precursor do neurotransmissor dopamina, inicialmente gera uma redução da manifestação dos sintomas motores na maioria dos pacientes. Porém, após certo tempo de tratamento, ocorre o surgimento de complicações motoras, como a discinesia induzida por L-DOPA (LID - LDOPA-induced dyskinesia). O desenvolvimento e a manifestação da LID também podem acompanhar uma resposta inflamatória anormal. Dados do grupo sugerem a enzima COX-2 e as células gliais como mediadores da LID. Estudos apontam que fármacos que reduzem a LID modulam a expressão de COX-2. Nosso objetivo, portanto, foi caracterizar a presença de fatores/mecanismos pró-inflamatórios no estriado lesionado de camundongos tratados com LDOPA. Nossos resultados serão apresentados em três capítulos. No primeiro capítulo, empregamos o modelo de camundongos hemiparkinsonianos (lesionados com 6- hidroxidopamina) e tratamos com L-DOPA por diferentes períodos de tempo (1, 7, 14 e 21 dias) para analisarmos o surgimento de fatores inflamatórios no estriado, como a enzima COX-2, o fator nuclear kappa-B (NF-?B) e a expressão e atividade dos astrócitos e micróglia. No segundo capítulo, demonstramos o potencial destas células gliais em produzir citocinas e/ou glutamato após estímulo com os principais neurotransmissores envolvidos com a LID, a DA (ou seu precursor L-DOPA) e glutamato. No terceiro capítulo, demonstramos o potencial terapêutico de drogas usadas na clínica - com propriedades anti-inflamatórias - de reduzirem a LID previamente estabelecida. Para tal, utilizamos o canabidiol (princípio ativo da Cannabis, usado no tratamento para epilepsia, entre outros) e o celecoxibe (inibidor específico da atividade enzimática da COX-2). Este estudo corrobora a existência de um processo inflamatório no estriado lesionado de camundongos parkinsonianos, exacerbado pelo tratamento com L-DOPA. A enzima COX-2 pode ter um papel fundamental no desenvolvimento da LID. Adicionalmente, este trabalho sugere que drogas utilizadas clinicamente com ação anti-inflamatória podem se tornar possíveis ferramentas terapêuticas para a redução desta desordem. Desta forma, relacionamos a produção de fatores inflamatórios e a ativação de células gliais à perpetuação de uma atividade pós-sináptica estriatal anormal que ocasionam a \"má plasticidade\" típica da LID. / Parkinson\'s disease (PD) is the second most common neurodegenerative disease in world population. The development of motor impairments related to this disease occurs due to its pathophysiology, which mainly promotes the neurodegeneration of the dopaminergic neurons in the substantia nigra pars compacta. Studies suggest the involvement of inflammatory pathways that exacerbate cell death in the pathophysiology of PD. The neuroinflammatory phenomenon is characterized by the activation of central nervous system cells, such as neurons, microglia and astrocytes, in addition to proinflammatory mediators that are elevated in patients with PD, such as the enzyme cyclooxygenase-2 (COX-2), tumor necrosis factoralpha (TNF-?), interleukin 1? (IL-1?) and interleukin-6 (IL-6), among others. These factors are present in neuroanatomic structures such as striatum and substantia nigra pars compacta. Chronic treatment with L-DOPA, the precursor of the neurotransmitter dopamine, initially generates a reduction in the manifestation of motor symptoms in the vast majority of patients, but after a certain time of treatment, motor complications begin to appear, such as L-DOPAinduced dyskinesia (LID). The development and manifestation of LID may also accompany an abnormal inflammatory response. Data from our group suggest the enzyme COX-2 as one of the mediators of LID. Studies also point out that drugs that reduce LID are able to modulate COX-2 expression. Our objective, therefore, was to characterize the presence of proinflammatory factors/mechanisms in the injured striatum of mice treated with L-DOPA. For this purpose, the present study will be divided into three chapters. In the first chapter, we used the hemiparkinsonian mice model (lesioned with 6-hydroxydopamine) treated with LDOPA for different time periods (1, 7, 14 and 21 days) to observe the appearance of inflammatory factors in the striatum, such as the COX-2 enzyme, nuclear factor kappa-B (NF- ?B) and the expression and activity of glial cells, represented by astrocytes and microglia. In the second chapter, we demonstrated the potential of glial cells to produce cytokines and/or glutamate after stimulation with the major neurotransmitters involved with LID, dopamine (or its precursor L-DOPA) and glutamate. Finally, in the third chapter, we demonstrate the therapeutic potential of drugs used in the clinic with anti-inflammatory properties to reduce previously established LID. For this, we used cannabidiol (the active constituent of Cannabis, used for the treatment of epilepsy, among others) and celecoxib (a specific COX-2 activity inhibitor). The present study corroborates the existence of an inflammatory process in the injured striatum of parkinsonian mice, exacerbated by treatment with L-DOPA. The COX-2 enzyme may play a key role in the development of LID. Additionally, this work suggests that drugs clinically used with anti-inflammatory action may become possible therapeutic tools for the reduction of this disorder. In this way, we relate the production of inflammatory factors and the activation of glial cells to the perpetuation of an abnormal striatal postsynaptic activity that causes the \"maladaptative plasticity\" typical of LID.
133

Prostaglandin E2 in Brain-mediated Illness Responses

Elander, Louise January 2010 (has links)
We are unceasingly exposed to potentially harmful microorganisms. The battle against threatening infectious agents includes activation of both the innate and of the adaptive immune systems. Illness responses are elicited and include inflammation, fever, decreased appetite, lethargy and increased sensitivity to painful stimuli in order to defeat invaders. While many of these signs of disease are controlled by the central nervous system, it has remained an enigma how signals from the peripheral immune system reach the brain through its blood-brain barrier, which precludes macromolecules, including cytokines, from diffusing into the brain parenchyma. Previous findings indicate the existence of a pathway across the blood-brain barrier, which includes binding of the cytokine interleukin-1 (IL-1) to its receptor in the brain vessels, thereby inducing the production of the prostaglandin E2 (PGE2) synthesizing enzymes cyclooxygenase-2 (Cox-2) and microsomal prostaglandin E synthase-1 (mPGES-1), which ultimately synthesize PGE2. PGE2 subsequently binds to any of the four prostaglandin E2 (EP) -receptors. Previous results from our laboratory have suggested that this pathway plays a critical role in the febrile response to infectious stimuli. The present thesis aims at further investigating the molecular events underlying immune-to-brain signalling, with special emphasis on fever, hypothalamic-pituitary-adrenal (HPA) -axis activation and anorexia and their connection to signalling molecules of the cytokine and prostaglandin families, respectively. In paper I, the molecular processes linking the proinflammatory cytokine interleukin-6 (IL-6) and PGE2 in the febrile response were investigated. Both IL-6 and PGE2 have been shown to be critical players in the febrile response, although the molecular connections are not known, i.e. if IL-6 exerts its effects up- or downstream of PGE2. Mice deficient in IL-6 were unable to respond to bacterial lipopolysaccharide (LPS) with a febrile response, but displayed similar induction of Cox-2 and mPGES-1, and similar concentrations of PGE2 in the cerebrospinal fluid as wild-type mice. Paradoxically, the IL-6 deficient mice responded with a dose-dependent elevation of body temperature in response to intracerebroventricularly injected PGE2. Furthermore, IL-6 per se was not pyrogenic when injected peripherally in mice, and did not cause increased levels of PGE2 in cerebrospinal fluid. IL-6 deficient mice were not refractory to the action of PGE2 because of excess production of some hypothermia-producing factor, since administration of a Cox-2 inhibitor in LPS-challenged IL-6 deficient mice did not unmask any hypothermic response, and neutralization of tumor necrosis factor α (TNFα), associated with hypothermia, did not produce fever in LPS-challenged IL-6 deficient mice. These data indicate that IL-6 rather than exerting its effects up- or down-stream of PGE2 affects some process in parallel to PGE2, perhaps by influencing the diffusion and binding of PGE2 onto its target neurons. In papers II and III, we injected the proinflammatory cytokine IL-1β in free-fed wild-type mice, in mice with a deletion of the gene encoding mPGES-1, or in mice deficient in the EP1, EP2 and EP3. Food intake was continuously measured during their active period, revealing that mPGES-1 deficient mice were almost completely resistant to anorexia induced by IL-1β. However, all of the investigated EP receptor deficient mice exhibited a normal profound anorexic response to IL-1β challenge, suggesting that the EP4 is the critical receptor that mediates IL-1β-induced anorexia. We also investigated the role of mPGES-1 in anorexia induced by lipopolysaccharide (LPS) in mPGES-1 deficient mice. The profound anorexic response after LPS-challenge was similar in mPGES-1 deficient and wild-type mice. To further investigate the anorectic behaviour after LPS injection, we pre-starved the animals for 22 hours before injecting them with LPS. In this paradigm, the anorexia was less profound in mPGES-1 knock-out mice. Our results suggest that while the inflammatory anorexia elicited by peripheral IL-1β seems largely to be dependent on mPGES-1-mediated PGE2 synthesis, similar to the febrile response, the LPS-induced anorexia is independent of this mechanism in free-fed mice but not in pre-starved animals. In papers IV and V, the role of prostanoids for the immune-induced HPA-axis response was investigated in mice after genetic deletion or pharmacological inhibition of prostanoid-synthesizing enzymes, including Cox-1, Cox-2, and mPGES-1. The immediate LPS-induced release of ACTH (adrenocorticotropic hormone and corticosteroids was critically dependent on Cox-1 derived prostanoids and occurred independently of Cox-2 and mPGES-1 derived PGE2. In contrast, the delayed HPA-axis response was critically dependent on immune-induced PGE2, synthesized by Cox-2 and mPGES-1, and occurred independently of Cox-1 derived enzymes. In addition, in the mPGES-1 deficient mice, the synthesis of CRH hnRNA and mRNA was decreased in the paraventricular nucleus of the hypothalamus after LPS-challenge, indicating that the delayed hormone secretion was mediated by PGE2-induced gene-transcription of CRH in the hypothalamus. The expression of the c-fos gene and Fos protein, an index of synaptic activation, was maintained in the paraventricular nucleus and its brainstem afferents both after unselective and Cox-2 selective inhibition as well as in Cox-1, Cox-2, and mPGES-1 knock-out mice. This suggests that the immune-induced neuronal activation of autonomic relay nuclei occurs independently of prostanoid synthesis and that it is insufficient for eliciting stress hormone release.
134

Untersuchung der Expression von Cyclooxygenase-2, VEGF und der Gefäßdichte im Nierenzellkarzinom / Analysis of the expression of Cyclooxygenase-2, VEGF and microvessel density in renal cell carcinomas

Galuschka, Libusa 11 August 2010 (has links)
No description available.
135

Assessing prediction error of genetic variants in Cox regression models

Balavarca Villanueva, Yesilda 20 April 2012 (has links)
No description available.
136

Validation des modèles statistiques tenant compte des variables dépendantes du temps en prévention primaire des maladies cérébrovasculaires

Kis, Loredana 07 1900 (has links)
L’intérêt principal de cette recherche porte sur la validation d’une méthode statistique en pharmaco-épidémiologie. Plus précisément, nous allons comparer les résultats d’une étude précédente réalisée avec un devis cas-témoins niché dans la cohorte utilisé pour tenir compte de l’exposition moyenne au traitement : – aux résultats obtenus dans un devis cohorte, en utilisant la variable exposition variant dans le temps, sans faire d’ajustement pour le temps passé depuis l’exposition ; – aux résultats obtenus en utilisant l’exposition cumulative pondérée par le passé récent ; – aux résultats obtenus selon la méthode bayésienne. Les covariables seront estimées par l’approche classique ainsi qu’en utilisant l’approche non paramétrique bayésienne. Pour la deuxième le moyennage bayésien des modèles sera utilisé pour modéliser l’incertitude face au choix des modèles. La technique utilisée dans l’approche bayésienne a été proposée en 1997 mais selon notre connaissance elle n’a pas été utilisée avec une variable dépendante du temps. Afin de modéliser l’effet cumulatif de l’exposition variant dans le temps, dans l’approche classique la fonction assignant les poids selon le passé récent sera estimée en utilisant des splines de régression. Afin de pouvoir comparer les résultats avec une étude précédemment réalisée, une cohorte de personnes ayant un diagnostique d’hypertension sera construite en utilisant les bases des données de la RAMQ et de Med-Echo. Le modèle de Cox incluant deux variables qui varient dans le temps sera utilisé. Les variables qui varient dans le temps considérées dans ce mémoire sont iv la variable dépendante (premier évènement cérébrovasculaire) et une des variables indépendantes, notamment l’exposition / The main interest of this research is the validation of a statistical method in pharmacoepidemiology. Specifically, we will compare the results of a previous study performed with a nested case-control which took into account the average exposure to treatment to : – results obtained in a cohort study, using the time-dependent exposure, with no adjustment for time since exposure ; – results obtained using the cumulative exposure weighted by the recent past ; – results obtained using the Bayesian model averaging. Covariates are estimated by the classical approach and by using a nonparametric Bayesian approach. In the later, the Bayesian model averaging will be used to model the uncertainty in the choice of models. To model the cumulative effect of exposure which varies over time, in the classical approach the function assigning weights according to recency will be estimated using regression splines. In order to compare the results with previous studies, a cohort of people diagnosed with hypertension will be constructed using the databases of the RAMQ and Med-Echo. The Cox model including two variables which vary in time will be used. The time-dependent variables considered in this paper are the dependent variable (first stroke event) and one of the independent variables, namely the exposure.
137

Överlevnadsanalys i tjänsteverksamhet : Tidspåverkan i överklagandeprocessen på Migrationsverket / Survival analysis in service : Time-effect in the process of appeal at the Swedish Migration Board

Minya, Kristoffer January 2014 (has links)
Migrationsverket är en myndighet som prövar ansökningar från personer som vill söka skydd, ha medborgarskap, studera eller vill jobba i Sverige. Då det på senare tid varit en stor ökning i dessa ansökningar har tiden för vilket ett beslut tar ökat. Varje typ av ansökning (exempelvis medborgarskap) är en process som består av flera steg. Hur beslutet går igenom dessa steg kallas för flöde. Migrationsverket vill därför öka sin flödeseffektivitet. När beslutet är klart och personen tagit del av det men inte är nöjd kan denne överklaga. Detta är en av de mest komplexa processerna på Migrationsverket. Syftet är analysera hur lång tid denna process tar och vilka steg i processen som påverkar tiden. Ett steg (som senare visar sig ha en stor effekt på tiden) är yttranden. Det är när domstolen begär information om vad personen som överklagar har att säga om varför denne överklagar. För att analysera detta var två metoder relevanta, accelerated failure time (AFT) och \multi-state models (MSM). Den ena kan predicera tid till händelse (AFT) medan den andra kan analysera effekten av tidspåverkan (MSM) i stegen. Yttranden tidigt i processen har stor betydelse för hur snabbt en överklagan får en dom samtidigt som att antal yttranden ökar tiden enormt. Det finns andra faktorer som påverkar tiden men inte i så stor grad som yttranden. Då yttranden tidigt i processen samtidigt som antal yttranden har betydelse kan flödeseffektiviteten ökas med att ta tid på sig att skriva ett informativt yttrande som gör att domstolen inte behöver begära flera yttranden. / The Swedish Migration Board is an agency that review applications from individuals who wish to seek shelter, have citizenship, study or want to work in Sweden. In recent time there has been a large increase in applications and the time for which a decision is made has increased. Each type of application (such as citizenship) is a process consisting of several stages. How the decision is going through these steps is called flow. The Swedish Migration Board would therefore like to increase their flow efficiency. When the decision is made and the person has take part of it but is not satisfied, he can appeal. This is one of the most complex processes at the Board. The aim is to analyze how long this process will take and what steps in the process affects the time. One step (which was later found to have a significant effect on time) is opinions. This is when the court requests information on what the person is appealing has to say about why he is appealing. To analyze this, two methods were relevant, accelerated failure time (AFT) and the multi-state models (MSM). One can predict time to event (AFT), the other to analyze the effect of time-manipulation (MSM) in the flow. Opinions early in the process is crucial to how quickly an appeal get judgment while the number of opinions increases the time enormously. There are other factors that affect the time but not so much as opinions. The flow efficiency can be increased by taking time to write an informative opinion which allows the court need not to ask for more opinions.
138

Développement de médicaments radiopharmaceutiques fluorés pour l'exploration en imagerie moléculaire TEP de la neuroinflammation / Fluorinated radiopharmaceuticals drug development for the exploration of neuroinflammation by PET molecular imaging

Elie, Jonathan 19 September 2016 (has links)
Les maladies du système nerveux central (SNC) comme la sclérose en plaques, les accidents vasculaires cérébraux et les maladies neurodégénératives (Alzheimer et Parkinson) entraînent une réponse inflammatoire au niveau cérébrale appelée neuroinflammation. Ce phénomène peut avoir pour conséquence la limitation de la propagation de la maladie mais aussi la réparation et la régénération des tissus touchés. La microglie, principale défense du SNC, passe à un stade activé lors de phénomènes neuroinflammatoires et va libérer de nombreux facteurs neuroprotecteurs mais aussi pro-inflammatoires. Cette dualité d’action va ainsi maintenir un cercle vicieux, pouvant conduire à la mort neuronale. Il serait donc intéressant de comprendre le mécanisme de la neuroinflammation pour diagnostiquer et traiter au mieux les pathologies du SNC. Il existe plusieurs cibles moléculaires, parmi elles se trouvent la CycloOXygénase 2 (COX-2), une enzyme qui permet la formation de prostaglandines à partir de l'acide arachidonique, qui apparaît précocement et est fortement surexprimée en cas de neuroinflammation. Cette enzyme serait donc une cible de choix pour le développement d’outils d’imagerie dans le but de diagnostiquer les pathologies dans lesquelles les processus inflammatoires centraux sont présents et ce afin d’améliorer la prise en charge du patient. La tomographie d’émission de positons (TEP) est une technique d’imagerie fonctionnelle très sensible qui permet de quantifier de manière fine les variations d’activités métaboliques ou moléculaires. Cette technique requiert l’utilisation de radiotraceurs marqués avec un émetteur béta+. / Central nervous system (CNS) disorders as multiple sclerosis, stroke and neurodegenerative diseases (Alzheimer’s and Parkinson’s) lead to inflammatory response in the brain called neuroinflammation. This phenomenon usually should result in limiting the spread of the disease but also repair and regeneration of the affected tissues. Microglia, the main defense of the SNC, which is activated during a neurodegenerative event leading to the production of many factors including neuroprotectors but also pro-inflammatories. This duality of actions will thereby maintain endless vicious circle leading to neuronal death. It would be interesting to understand the neuroinflammation mechanism to better diagnose and treat CNS diseases. There are several molecular targets, among them are the CycloOXygenase 2 (COX-2), an enzyme which allows the formation of prostaglandins from arachidonic acid, which appears early and it is significantly overexpressed in case of neuroinflammation. This enzyme is therefore a good biological target for the development of imaging tools in order to diagnose pathologies in which central inflammatory processes are present in order to improve patient care. Postiron emission tomography (PET) is a very sensitive functional imaging technique that quantifies minute variations in metabolic or molecular activities. This technique requires the use of radiotracers labeled with a beta + emitter.
139

Development and characterization of models of resistance to T-DM1 / Développement et caractérisation de modèles de résistance au T-DM1

Sauveur, Juliette 12 December 2016 (has links)
Le T-DM1 est un immunoconjugué composé de l'anticorps trastuzumab qui cible HER2 lié au DM1, un agent anti-tubuline dérivé de la maytansine. Malgré son efficacité, la résistance acquise au T-DM1 a été démontré lors des tests précliniques et chez certains patients. Nous avons développé des lignées résistantes à partir de la lignée de cancer du sein MDA-MB-361 et de la lignée de cancer de l'œsophage OE-19, que nous avons exposées au T-DM1 à doses croissantes pendant une longue durée en absence ou en présence de ciclosporine A (CsA). A partir de ces conditions nous avons obtenus les lignées “TR” qui ont été exposées uniquement au T-DM1 et “TCR” qui ont été exposées au T-DM1 et CsA. Nous avons observé une augmentation de la vitesse de migration et une diminution de la force d'adhésion chez OE-19 TCR associées à une sensibilité accrue à un inhibiteur de RHOA. Aussi, la voie des prostaglandines était dérégulée chez OE-19 TR et TCR, avec une forte augmentation de l'expression de COX-2 et de prostaglandine E2 dans la lignée OE-19 TR. La sensibilité à l'aspirine, un inhibiteur des cyclooxygenases 1-2, était accrue chez les deux lignées OE-19 résistantes par rapport à la lignée parentale. En conclusion nous avons démontré que différentes voies de signalisation peuvent être impliquées dans la résistance au T-DM1. Nos résultats restent à être validés chez les patients. Nous suggérons que cibler la voie de régulation de la composition du cytosquelette ou la voie des prostaglandines pourrait permettre d'obtenir un effet thérapeutique dans le cas de cancers résistants au T-DM1 / T-DM1 is an antibody-drug conjugate composed of the monoclonal antibody trastuzumab linked to DM1, a potent tubulin binding agent. Despite its efficacy in the treatment of HER2-positive breast cancer patients, acquired resistance to T-DM1 was observed during clinical trials. In order to study resistance mechanisms to T-DM1, we developed resistance models using OE-19 (esophageal) and MDA-MB-361 (breast) cancer cell lines in the absence or presence of ciclosporin A (CsA), an inhibitor of MDR1 mediated efflux. Resistant cells selected with T-DM1 alone are named “TR” and cells selected in the presence of T-DM1 and CsA are called “TCR”. OE-19 TCR cells showed modifications in adhesion gene expression, migration and adhesion strength, combined with an increased sensitivity to a RHOA inhibitor. Also, OE-19 TR cells presented an overexpression of COX-2 associated with an increased amount of PGE2 in the supernatant. A deregulation of the genes involved in the prostaglandin pathways was found in OE-19 TR and TCR cells, associated with increased sensitivity to aspirin. In conclusion, we found two signaling pathways deregulated in cell lines resistant to T-DM1. These results need to be validated using samples from patients resistant to T-DM1. Targeting the adhesion or the prostaglandin pathway could be of benefit for patients with T-DM1 resistant cancers
140

Estudo de fatores prognósticos em pacientes submetidos ao transplante de medula óssea para tratamento de leucemia mielóide crônica. / Study of prognostic factors in patients undergoing bone marrow transplantation for treatment of chronic myeloid leukemia.

Maria Rita Lustosa Byington 19 August 1999 (has links)
O presente estudo compreende 96 transplantes de medula óssea (TMO) de doadores HLA-idênticos em pacientes portadores de Leucemia Mielóide Crônica, no período de Junho de 1986 a Junho de 1998. A autora selecionou diversas covariáveis para serem estudadas como fatores prognósticos de cinco desfechos principais: ocorrência de doença enxerto contra hospedeiro (DECH) aguda e crônica, incidência de recaída, sobrevida livre de doença (SLD) e sobrevida global (SG). As covariáveis estudadas foram: idade, sexo, escolaridade, tempo entre o diagnóstico e o transplante, fase da doença ao transplante, regime de condicionamente, profilaxia de DECH, compatibilidade de sexo entre doador e receptor, sexo do doador, tamanho do baço e do fígado, percentagem de blastos e número de plaquetas no sangue periférico na primeira consulta ao CEMO, ocorrência e grau de DECH aguda, ocorrência de DECH crônica e tempo para recuperação de plaquetas após o TMO. Não foi encontrada associação estatisticamente significativa num nível de 95% de confiança entre qualquer das covariáveis e a ocorrência de DECH crônica ou de recaída. A ocorrência de DECH aguda mostrou-se associada apenas com a fase da doença ao transplante. As covariáveis que se mostraram associadas com a sobrevida global e a sobrevida livre de doença foram: a percentagem de blastos no sangue periférico e tamanho do baço na primeira consulta ao CEMO, a fase da doença ao transplante, o tipo de profilaxia de DECH, a ocorrência e o grau de DECH aguda e o tempo para recuperação de plaquetas num nível acima de 20 x 103/mm3. / This study comprises 96 bone marrow transplantations (BMT) from HLA-identical siblings in patients with Chronic Myeloid Leukaemia (CML), from June 1986 to June 1998. The author selected several covariates to be studied as prognostic factors for five main endpoints: acute and chronic graft versus host disease (GVHD) occurrence, relapse incidence (RI), disease free survival (DFS) and overall survival (OS). The covariates studied were: age, sex, years of schooling, time from diagnosis to transplantation, disease phase at BMT, conditioning regimen, GVHD prophylaxis, sexmatch between donor-receptor, donor sex, spleen and liver size, blasts percentage and platelet counts in peripheral blood at first consultation at CEMO, acute GVHD occurrence and grade, chronic GVHD occurrence and time to platelet recovery after BMT. No statistically significant association was found between the covariates studied and the occurrence of acute or chronic GVHD or of relapse. The covariates found to have an association with overall survival (OS) and disease free survival (DFS) were the percentage of blasts in peripheral blood and the spleen size at first consultation, the disease phase at transplant, type of GVHD prophylaxis, the occurrence and grade of acute GVHD and the time to platelet recovery above 20 x 103/mm3.

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