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Efeitos da inibição de Aurora A sobre a proliferação e fenótipo de células derivadas de hepatocarcinoma humano. / A inhibition effects in proliferation and morphology in cells derivated of Hepatocellular Carcinoma.Almeida, Raquel Bernardeth de 10 September 2010 (has links)
Hepatocarcinoma (HCC) é o mais comum tumor maligno primário do fígado. Aurora A é importante durante o ciclo celular, atuando na maturação centrossômica e sua separação, entrada em mitose, montagem de fuso bipolar, alinhamento dos cromossomos na placa metafásica e citocinese. Expressão alterada de Aurora A tem sido associada com o desenvolvimento do tumor e sua superexpressão ocorre em 60% dos HCCs. Inibidores de Aurora quinases têm sido desenvolvidos como drogas antitumorais. 4(4`-Benzamidoanilina)-6,7dimetoxiquizanoline, BADIM, é um recém desenvolvido inibidor da Aurora. Nosso estudo investigou os efeitos de BADIM na linhagem celular HepG2, derivada de HCC, quando tratada com 300, 600 e 1200nm de BADIM por 24 e 48h. Observamos inibição de proliferação, aumento de células tetraplóides, binucleadas e gigantes, bloqueio em G2/M do ciclo celular, alterações nos microtúbulos, mitoses atípicas e apoptose. Por conseguinte, este inibidor é um agente promissor para estudos em HCC, pois atua em pontos críticos relacionados com o processo de tumorigênese. / Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of liver. Aurora A is important during cell cycle, including centrosome maturation and separation, mitotic entry, bipolar-spindle assembly, chromosome alignment on metaphase plate and cytokinesis. Altered expression of Aurora A has been associated with tumor development and its overexpression occurs in 60% of HCC. Aurora kinases inhibitors have been developed as antitumoral drugs. 4(4`-Benzamidoanilino)-6,7-dimethoxiquizanolina, BADIM, is a new Aurora inhibitor. Our study aimed investigates the BADIM effects on HepG2 cell line, derivates of HCC, when treated in 300, 600 and 1200nM for 24 and 48h. We observed inhibition of cell proliferation, increase of tetraploids, binucleated and giant cells, arrest in G2/M cell cycle, microtubules alterations, aberrant cell divisions and apoptosis. Therefore this inhibitor is a promising agent for studies in HCC, since it acts at critical points related to tumorigenesis.
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Ligand selective regulation of cell growth by the Ah receptor through activation of TGFβ signaling / Ligand selective regulation of cell growth by the Ah receptor through activation of TGF-beta signalingKoch, Daniel C. 28 March 2015 (has links)
The Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor and member of the basic helix-loop-helix Per/ARNT/Sim (bHLH/PAS) family of chemosensors and developmental regulators. As a member of the PAS domain family of transcription factors responsive to exogenous signals, the AhR exerts influence on many processes relating to cellular fate.
The activation of AhR is widely associated with toxic endpoints related to dioxin exposure. However, the AhR also activates endogenous gene programs related to development, cellular growth, and differentiation. The AhR is able to bind a variety of ligands, leading to a wide range of biological outcomes. Recent reports have shown that the AhR can mediate tumor suppressive effects. As a ligand-activated transcription factor, the AhR has the potential to actuate a variety of transcriptional programs that are dependent on the AhR ligand.
Our central hypothesis is that AhR ligands can be identified that are capable of initiating tumor suppressive functions of the AhR.
We utilized complementary cell-based and in silico virtual screening approaches to identify potential AhR ligands. We developed homology models of the AhR ligand-binding domain (LBD) for virtual ligand screening (VLS) of small molecule libraries. This led to the identification of new AhR ligands 5,7- dihydroxyflavanone!and 5-hydroxy-7-methoxyflavone. Additional small molecule libraries were screened in parallel that led to identification of flutamide as a putative AhR ligand. Flutamide is clinically approved for the treatment of prostate cancer due to its ability to antagonize androgen receptor mediated transcription. We investigated the biological effects of flutamide in AhR positive cancer cells that do not express the androgen receptor and found that flutamide inhibited the growth of HepG2 cells. Suppression of AhR expression reversed the anti-proliferative effects of flutamide.
We tested 15 structural analogs of flutamide, including the flutamide metabolite 2-hydroxyflutamide for activation of AhR transcriptional activity. Flutamide is unique in its ability to activate the AhR, and suppresses hepatoma cell growth. These data suggests that flutamide-induced AhR transcriptional activity is required to initiate the tumor suppressive effects. We examined changes in cell cycle checkpoint proteins after flutamide treatment and discovered increased expression of cell cycle inhibitory proteins p27[superscript Kip1] and p15[superscript INK]. We also found that transforming Growth Factor β1 (TGFβ1), which
regulates both p27[superscript Kip1] and p15[superscript INK], is upregulated by flutamide. We demonstrate
that TGFβ1 is upregulated by flutamide in an AhR-dependent manner and is
required for suppression of proliferation by flutamide. We identify specific and
unique transcriptional signatures of the AhR upon activation by flutamide, that
are distinct from the potent AhR agonist 2,3,7,8-Tetrachlorodibenzo-p-dioxin
(TCDD).
In summary, we characterize flutamide as an AhR ligand and demonstrate
its AhR-dependent tumor suppressive effects in hepatoma cells. We provide the
first direct evidence that AhR regulates TGFβ signaling in a ligand dependent
manner. We demonstrate that the AhR-induced downstream transcriptional
signature and subsequent biological effects are specific to the AhR ligand. Our
studies have broad impact for characterizing the AhR as a new therapeutic target
in hepatocellular carcinoma. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from March 28, 2013 - March 28, 2015
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Tyrosinemia type I as a model for studying epigenetic events in the aetiology of metabolic disease associated hepatocarcinoma / Gouws, C.Gouws, Chrisna January 2011 (has links)
Occupational risk management can be a catalyst in generating superior returns for all stakeholders on a sustainable basis. A number of companies in South Africa have implemented Cardinal Rules of Safety adopted from international companies to ensure the safety of their employees. The purpose of this study was to measure the impact of the cardinal rules on employee safety behaviour implemented at power stations in Mpumalanga.
The empirical study was done by using a questionnaire as measuring instrument. The questionnaire was developed from a literature review and contains questions and items relevant to the initial research problem. The questionnaire comprised of five–point Likert scale type questions.The convenience sampling method was applied identifying 90 participants at three different power stations in Mpumalanga taking part in the study.
Statistical analysis was performed by the Statistical Consulting Service of the North–West University using SPSS. Cronbach’s alpha co–efficients was used to determine the reliability of the factors. Descriptive statistics (Mean, standard, deviation, were used in the compiling of the profile of the results. While Spearman’s rho correlation coefficient was calculated to identify practically significant associations between variables and factors
The research findings suggest that there is practical significant correlation between the factors that were measured. The opinion given by respondents suggests that cardinal rules of safety were implemented, given all the necessary support by management and enforced throughout the organisation. / Thesis (Ph.D. (Biochemistry))--North-West University, Potchefstroom Campus, 2012.
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Tyrosinemia type I as a model for studying epigenetic events in the aetiology of metabolic disease associated hepatocarcinoma / Gouws, C.Gouws, Chrisna January 2011 (has links)
Occupational risk management can be a catalyst in generating superior returns for all stakeholders on a sustainable basis. A number of companies in South Africa have implemented Cardinal Rules of Safety adopted from international companies to ensure the safety of their employees. The purpose of this study was to measure the impact of the cardinal rules on employee safety behaviour implemented at power stations in Mpumalanga.
The empirical study was done by using a questionnaire as measuring instrument. The questionnaire was developed from a literature review and contains questions and items relevant to the initial research problem. The questionnaire comprised of five–point Likert scale type questions.The convenience sampling method was applied identifying 90 participants at three different power stations in Mpumalanga taking part in the study.
Statistical analysis was performed by the Statistical Consulting Service of the North–West University using SPSS. Cronbach’s alpha co–efficients was used to determine the reliability of the factors. Descriptive statistics (Mean, standard, deviation, were used in the compiling of the profile of the results. While Spearman’s rho correlation coefficient was calculated to identify practically significant associations between variables and factors
The research findings suggest that there is practical significant correlation between the factors that were measured. The opinion given by respondents suggests that cardinal rules of safety were implemented, given all the necessary support by management and enforced throughout the organisation. / Thesis (Ph.D. (Biochemistry))--North-West University, Potchefstroom Campus, 2012.
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Traitement du virus de l'hépatite C (VHC) par agents antiviraux directs : modélisation de l'optimisation des traitements et impact sur l'histoire naturelle et l'épidémiologie / Direct-acting antiviral treatments of hepatitis C virus (HCV) : treatment optimization and impact on natural history and epidemiologyVirlogeux, Victor 10 September 2018 (has links)
Le traitement du virus de l'hépatite C (VHC) a connu une révolution récente, rapide et exemplaire grâce à l'arrivée des agents antiviraux directs (AAD) en plusieurs vagues depuis 2011, détrônant ainsi la bithérapie interféron-pégylé/ribavirine. Ces nouveaux traitements ont été rapidement confrontés à des limites concernant leur efficacité et leur tolérance notamment à leurs débuts avec les inhibiteurs de la protéase NS3/4A de première génération. L'arrivée de nouveaux AAD sur le marché lors d'une 2ème vague en 2014 a permis toutefois de surpasser celles-ci et de devenir le traitement de référence du VHC.Leur efficacité remarquable a laissé naître l'idée d'une potentielle élimination du VHC grâce à l'utilisation universelle de ces traitements. Cependant, leur coût élevé et les comportements à risque observés dans des sous-groupes de population (utilisateurs de drogues intraveineuses et homosexuels) restent encore des problématiques cruciales à surmonter pour espérer atteindre les objectifs fixés par l'Organisation Mondiale de la Santé en 2030 concernant l'élimination du VHC. De plus ces traitements, permettant l'élimination virale quasi-systématique et donc consécutivement une diminution du risque de complications hépatiques, ont été récemment confrontés à une polémique concernant un potentiel risque de récidive précoce de carcinome hépatocellulaire (CHC) suite à une exposition à ces derniers.Le travail présenté dans cette thèse s'articule autour de trois problématiques ayant toutes pour objectif principal d'optimiser l'utilisation de ces traitements dans l'optique de contrôler l'histoire naturelle de la maladie à l'échelle individuelle et à l'échelle populationnelle par l'intermédiaire de diverses méthodes statistiques.Nos résultats ont permis de montrer au sein d’une première problématique ayant exploré l'efficacité et la tolérance de ces traitements antiviraux à l’échelle individuelle: (i) une efficacité antivirale moindre que celle annoncée dans les essais de phase III des inhibiteurs de protéase de première génération(télaprévir et bocéprévir), (ii) un effet indésirable significatif des inhibiteurs de protéase de première génération sur la fonction rénale, (iii) une tolérance moins bonne de ces premières molécules que lors du traitement par bithérapie avec une incidence accrue d'anémie probablement liée à un surdosage en ribavirine induit par les inhibiteurs de protéase et (iv) une efficacité antivirale remarquable des AAD arrivés depuis 2014 sans impact des caractéristiques du patient ni des dosages pharmacologiques sur la réponse virologique. Dans un second temps, la problématique d'un risque de récidive de CHC accru après un traitement par AAD a également été explorée par l'analyse d'une cohorte locale, celle-ci ayant conclu à l'absence de risque accru comparé à un groupe de patients non exposés. Enfin, nos travaux basés sur la modélisation de la transmission du VHC en France dans la population coinfectée VIH-VHCont montré qu'un taux annuel de traitement par AAD de 50% était nécessaire dans la population homosexuelle ayant des pratiques à haut-risque de transmission pour contrer l'épidémie actuellement observée.Nos travaux ont donc permis d'apporter des données pour optimiser l'utilisation des nouveaux traitements anti-VHC par l'intermédiaire de diverses approches statistiques et ont apporté des éléments de réponse aux grandes problématiques actuelles. L'efficacité exemplaire et la tolérance quasi-parfaite des dernières molécules antivirales permettent une utilisation universelle de ces traitements dans toutes les populations de patients. Des études complémentaires robustes sont cependant nécessaires pour apporter des arguments à la question de la récidive du CHC. Des efforts sont également attendus concernant l'accès au traitement, la diminution des coûts associés et un dépistage renforcé du VHC pour espérer pouvoir éradiquer un jour cette maladie. / The arrival of direct-acting antivirals agents (DAAs) has spurred a rapid revolution in the treatment of hepatitis C virus (HCV), supplanting the previous standard of care, i.e. pegylated interferon and ribavirin. These new treatments are associated with an increased rate of virological response however they rapidly faced some limits more particularly at the beginning with the first generation NS3/4A protease inhibitors. From 2014 on the second wave of DAA was available for treatment of chronic HCV infection and surpassed previous encountered limits. These treatments are nowadays the gold standard for HCV treatment in high-income countries.The idea of HCV eradication recently emerged since DAA treatment are highly effective. However, their associated high cost and recent high-risk behaviors associated with an increased risk of HCV transmission (among intravenous drug users and homosexuals) have been reported. These issues need therefore to be addressed in order to achieve the objectives of the World Health Organization for 2030 of an HCV eradication. Moreover, these treatments allow a sustained virological response in almost all patients and consequently reduce the risk of liver-related complications, but a recent controversy regarding a potential increased risk of hepatocellular carcinoma after DAA treatment has been raised.Three issues will be extensively discussed in this manuscript regarding how these treatments can be used to optimize their effect on HCV natural history at the individual and population level through different statistical approaches.As regards the first issue, this project allowed us to demonstrate regarding the tolerance and efficacy of DAA treatment: (i) a lower antiviral efficacy than previously reported in the phase III trials for first generationprotease inhibitor regimen (telaprevir and boceprevir), (ii) impairment of renal function during first generation protease inhibitor treatment, (iii) an increased rate of reported side effects during first-generation protease inhibitor treatment and more particularly anemia, potentially related to an increased ribavirin biodisponibility induced by protease inhibitor intake and (iv) a remarkable antiviral efficacy of second generation DAAs without impact of patients' characteristics norpharmacology on virological response rate. The recent issue regarding a higher risk of HCC recurrence after DAA treatment was also explored through a local cohort study and no impact of DAA treatment was observed when comparing DAA-exposed vs non DAA-exposed patients. Finally, we conducted amodelling study on HCV transmission in the coinfected HIV-HCV French population and our results suggested that an annual DAA treatment coverage rate of 50% was required in the homosexual population with high-risk behaviors to counter the recent observed epidemic in this population.Our different works provide new insights on how to optimize the use of DAA treatment through several statistical approaches and bring new elements for discussion on the recent controversy. The new DAA have an excellent efficacy and tolerance profile and should be universally used in all populations without restriction. However, further studies are required to explore on a deeper level the question regarding HCC recurrence after DAA treatment. Efforts are also still needed regarding DAA treatment access, associated costs and HCV screening to reach the objective of HCV eradication
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Cancer du foie au Cambodge : état des lieux épidémiologiques, description des médecines traditionnelles utilisées et évaluation d'espèces médicinales sélectionnées / Liver cancer in Cambodia : epidemiological survey, description of traditional medicine used and biological evaluation of some medicinal plant species selectedChassagne, François 17 October 2017 (has links)
Le cancer du foie est le 6ème cancer le plus fréquent et le 2ème plus meurtrier dans le monde. Au Cambodge, en raison du contexte historique et économique, les données précises concernant cette pathologie manquent. A l'aide d'outils épidémiologiques, nous avons décrit les caractéristiques de 553 patients atteints de cancer du foie à l'hôpital Calmette à Phnom Penh, et ainsi mis en évidence l'importance de l'infection par les virus des hépatites B et C chez les sujets étudiés. Puis, nous avons documenté les connaissances de 42 de ces patients vis-à-vis de leur maladie. Nous avons détaillé leurs itinéraires thérapeutiques, mis en évidences des pratiques à risques (forte utilisation d'injections thérapeutiques et de techniques de dermabrasion), et le recours fréquent à des médecines dites traditionnelles. Nous avons ensuite tenté de comprendre les stratégies de prise en charge des patients souffrant de maladies hépatiques par les médecins traditionnels, et mis en évidence la variété des remèdes utilisés et l'importance de la perception khmère des propriétés des plantes. Enfin, à l'aide d'un modèle in vitro de culture de cellules cancéreuses hépatiques couplé à des outils d'analyse métabolomique, nous avons évalué 10 espèces médicinales, sélectionnées sur des critères bibliographiques et de terrain, et tenté d'identifier les composés potentiellement responsables de l'activité antiproliférative observée. / Liver cancer is the 6th most common and 2nd most lethal cancer in the world. In Cambodia, due to the historical and economic context, there is a lack of accurate data on this pathology. Using epidemiological tools, we described the characteristics of 553 patients with liver cancer at the Calmette Hospital in Phnom Penh, and thus highlighted the importance of infection with hepatitis B and C viruses in the subjects studied. Then we documented the knowledge of 42 of these patients about their disease. We have detailed their therapeutic itineraries, highlighted risky practices (high use of therapeutic injections and dermabrasion techniques) and the use of traditional medicines. We then attempted to understand strategies for the management of patients with liver diseases by traditional healers, and highlighted the variety of remedies used and the importance of Khmer perception of plant properties. Finally, using an in vitro model of liver cancer cell culture coupled with metabolic analysis tools, we evaluated 10 medicinal species, selected on the basis of bibliographic and field criteria, and attempted to identify the compounds potentially responsible for the antiproliferative activity observed.
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Prevalência da mutação ser-249 no gene TP53 em pacientes com carcinoma hepatocelular e cirrose hepática sem carcinoma hepatocelular diagnosticados em Vitória, Espírito SantoCarvalho, Fernanda Magri de 19 March 2009 (has links)
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Previous issue date: 2009-03-19 / A incidência do carcinoma hepatocelular (CHC) apresenta grandes variações geográficas associadas a diferentes prevalências dos seus fatores etiológicos mais comuns. Embora não se conheça a sua real incidência no Espírito Santo, o CHC é freqüentemente diagnosticado no estado, associado à infecção com os vírus da hepatite B (VHB) e da hepatite C. No entanto, cerca de 40% dos casos não apresentam evidências destes fatores etiológicos. Por essa razão, buscou-se verificar se outro fator aflatoxinas poderia estar envolvido na etiologia do CHC no ES. Nas regiões tropicais, as aflatoxinas são consideradas um importante fator etiológico do CHC, especialmente quando associadas à infecção com o VHB. O objetivo da presente investigação foi estudar a prevalência da mutação específica ser-249 no gene TP53, cuja presença é um indicador indireto de contaminação alimentar com estas micotoxinas e sua relação com a infecção pelo VHB. Foram investigadas 41 amostras de CHC e 74 amostras de cirrose hepática sem CHC, utilizando-se a metodologia de PCR-RFLP e sequenciamento. O DNA do VHB foi pesquisado com iniciadores específicos para seis diferentes regiões do seu genoma. Os iniciadores utilizados foram escolhidos considerando as regiões mais conservadas do genoma viral e englobando os oito genótipos já identificados do VHB. A presença do DNA do VHB foi observada em 46% (19/41) dos casos de carcinoma hepatocelular estudados. A mutação ser-249 TP53 foi observada em 15% (6/41) e 1,5% (1/69) dos casos de CHC e de cirrose hepática sem CHC associado, respectivamente, não havendo correlação estatisticamente significativa com a presença do DNA do VHB. Foram encontradas outras quatro mutações no códon 250 do gene TP53. A prevalência total de 24% (10/41) de mutações ser-249 e mutações no códon 250 nos pacientes com carcinoma hepatocelular possivelmente também associadas à contaminação com aflatoxinas pode indicar a provável exposição alimentar às aflatoxinas no Espírito Santo / The hepatocellular carcinoma (HCC) incidence has large geographic variation, which is associated with the different prevalences of its most common etiological factors. Although its real incidence in the Espirito Santo State is not known, the HCC is frequently diagnosed in ES associated with hepatitis B (HBV) and C virus infections. However, approximately 40% of the cases do not present known etiological factors. Therefore, it was the purpose of this study to verify if another factor - aflatoxins - could be involved in the HCC etiology in ES. In tropical areas, the aflatoxins are considered an important etiological factor of CHC, especially when associated with HBV infection. The aim of this investigation was to study the prevalence of the specific ser-249 mutation in the TP53 gene was studied, that indicates indirect food contamination with aflatoxins and its association with HBV infection. Forty-one HCC samples and seventy-four hepatic cirrhosis samples were investigated, using PCRRFLP methodology and sequencing. The HBV DNA was amplified with specific primers targeting six different regions of its genome. Primers were chosen considering the most conserved regions of the viral genome and encompassing the eight known genotypes of HBV. Presence of HBV DNA was observed in 46% (19/41) of the hepatocellular carcinoma cases studied. The ser-249 TP53 mutation was observed in 15% (6/41) and 1,5% (1/69) of the HCC and cirrhosis cases respectively, not having statistical correlation with the presence of HBV DNA. Other four mutations in TP53 codon 250 were found, yielding a total mutation prevalence of 24% (10/41), considering both ser-249 and codon 250 mutations, possibly also associated with food contamination by aflatoxins, and suggesting an alimentary exposition to aflatoxins in Espirito Sant
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Particularités du carcinome hépatocellulaire au Pérou : étude clinique, génétique et de médecine intégrative / Peculiarities of hepatocellular carcinoma in Peru : clinical and genetic study and integrative medicineRojas Rojas, Teresa Milagros 24 November 2017 (has links)
Le cancer du foie est la deuxième cause de mortalité due au cancer dans le monde, avec près de 83% des cas et 84% des décès ayant lieu dans les pays en voie de développement. Le type histologique de cancer du foie le plus fréquemment répandu est le carcinome hépatocellulaire (HCC). Selon la littérature disponible, le HCC affecte électivement des sujets masculins de plus de 50 ans ayant développé préalablement une cirrhose hépatique. Nos objectifs étaient donc i) de confirmer au niveau moléculaire la singularité du HCC chez les patients péruviens, ii) d'évaluer les stratégies d'intervention chirurgicale dans le contexte clinique iii) d'étudier les pratiques de médecine traditionnelle, complémentaire et alternative (TCAM) chez les patients iv) d'étendre cette étude à d'autres pays en développement afin d'obtenir une vision plus globale de la problématique liée au cancer du foie. Nous avons montré que le HCC péruvien présentait un spectre de mutations unique. De plus, nous avons démontré que les arbres décisionnels thérapeutiques développés jusqu'alors ne sont pas adaptés au contexte clinique rencontré au Pérou, et qu'ils sont susceptibles d'être réévalués afin d'augmenter la proportion de patients pouvant être candidats à une intervention chirurgicale. Nous avons caractérisé le fait que la majorité des patients avec un HCC a recours à la phytothérapie de manière complémentaire et alternative. Enfin, nous avons réalisé une étude d'épidémiologie clinique préliminaire sur le cancer du foie au Cambodge. Nous avons décrit une situation clinique distincte de celle rencontrée au Pérou, mais qui nécessite également des recherches scientifiques et cliniques plus approfondies. / Liver cancer is the second leading cause of cancer related death in the world. About 83% of liver cancer cases occur in the developing world. The preeminent histotype of liver cancer is hepatocellular carcinoma (HCC). According to the relevant literature, HCC is defined by patient profile corresponding grossly to cirrhotic males over 50 years old. The aims of the present work were thus to i) confirm at the molecular level the pecularity of Peruvian HCC; ii) evaluate the surgical intervention strategies for HCC in the clinical context encountered in Peru; iii) study the practices of traditional, complementary and alternative medicine ( TCAM) among patients; iv) widen the study to other low- and middle income countries in order to provide deeper insights on liver cancer. We found that Peruvian HCC displayed a unique mutation spectrum. Furthermore, we demonstrated that current therapeutic algorithms for liver cancer are not suited to the clinical context found in Peru. These therapeutic algorithms should be reevaluated in order to increase the number of patients who could be eligible for surgical intervention. Moreover, we characterized the fact that the majority of Peruvian HCC patients rely on phytotherapy in a complementary and alternative way. Finally, we undertook a preliminary clinical, epidemiological study on liver cancer in Cambodia. We delineated a clinical context distinct from the one described in Peru that also requires further clinical and scientific investigation.
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Diagnostische Wertigkeit des Tumormarkers AFP beim hepatozellulären Karzinomrezidiv nach Lebertransplantation / Retrospektive Single-Center-Studie / Diagnostic Value of AFP as a marker of Hepatocellular Carcinoma Recurrence after Liver TransplantationNörthen, Aventinus 25 April 2017 (has links)
No description available.
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Evaluation préclinique de thérapies innovantes pour le carcinome hépatocellulaire et l'infection chronique par le virus de l'hépatite C / Preclinical evaluation of innovative therapies for hepatocellular carcinoma and chronic infection with hepatitis C virusWu, Tao 09 October 2014 (has links)
L’infection par le virus de l’hépatite C (VHC) représente un problème majeur de santé publique du fait de sa prévalence élevée et de la sévérité de ses complications, cirrhose et carcinome hépatocellulaire (CHC). Les objectifs du projet de thèse sont (i) de mettre en place et caractériser des modèles orthotopiques de CHC chez le petit animal (xénogreffe orthotopique de la lignée de CHC humaine Huh-7 exprimant le gène rapporteur de la luciférase chez la souris immunodéficiente) et chez le gros animal (transplantation autologue d’hépatocytes de cochon préalablement transformés ex vivo par transfert par voie lentivirale d’une combinaison de six oncogènes) et (ii) d’apporter la preuve de concept d’une approche innovante d’immunothérapie adoptive allogénique du CHC et de l’infection chronique par le VHC, par administration de lymphocytes génétiquement modifiés (LGM) allogéniques exprimant un gène de toxicité conditionnelle, ou gène suicide. Un tel gène suicide permet le contrôle des LGM, conduisant à leur élimination conditionnelle en cas d’effets secondaires indésirables. Ainsi, nous avons montré que, à dose élevée, ces LGM exercent in vitro une activité cytotoxique vis-à-vis de lignées de CHC humaines et in vivo une activité anti-tumorale vis-à-vis de tumeurs orthotopiques Huh-7. A faible dose, les LGM présentent une activité anti-virale vis-à-vis du VHC sans induire de toxicité. Ces résultats ouvrent la perspective à une approche originale d’immunothérapie du CHC, associée aux traitements actuels et de prévention de la réinfection du greffon hépatique par le VHC lors de la transplantation. / The hepatitis C virus (HCV) infection is a major problem of public health, due to its high prevalence and to the severity of its complications, cirrhosis and hepatocellular carcinoma (HCC). The aims of the thesis project are (i) to set up and characterize orthotopic HCC models in the small animal (orthotopic transplantation in immunodeficient mice of the human HCC cell line Huh-7, expressing the luciferase reporter gene) and in the large animal (autologous transplantation of porcine hepatocytes previously ex vivo-transformed by lentiviral-meidated transfer of a combination of six oncogenes) and (ii) to provide the proof-of-concept of an innovative adoptive allogeneic immunotherapy approach for the treatment of HCC and prevention of liver graft reinfection by HCV, through the administration of allogeneic suicide gene-modified lymphocytes (GML). Such a suicide gene allows for the control of GML, leading to their conditional elimination in case of undesirable side effects. Thus, we have demonstrated that, at high dose, these GML present an in vitro cytotoxic activity toward HCC cell lines and an in vivo antitumoral effect against orthotopic Huh-7 tumors. At low level, the GML have an antiviral activity against HCV, without toxicity against target cells. These results open the perspective for an original approach of immunotherapy for the treatment of HCC in association with current treatments and for the prevention of liver graft reinfection by HCV at time of liver transplantation.
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