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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.
51

Conversational Engine for Transportation Systems

Sidås, Albin, Sandberg, Simon January 2021 (has links)
Today's communication between operators and professional drivers takes place through direct conversations between the parties. This thesis project explores the possibility to support the operators in classifying the topic of incoming communications and which entities are affected through the use of named entity recognition and topic classifications. By developing a synthetic training dataset, a NER model and a topic classification model was developed and evaluated to achieve F1-scores of 71.4 and 61.8 respectively. These results were explained by a low variance in the synthetic dataset in comparison to a transcribed dataset from the real world which included anomalies not represented in the synthetic dataset. The aforementioned models were integrated into the dialogue framework Emora to seamlessly handle the back and forth communication and generating responses.
52

Från projektorganisation till förvaltningsorganisation : en studie av överlämningsarenan

Hammar, Ann-Margreth January 2011 (has links)
IT-system är idag vanligt förekommande i de flesta typer av  organisationer och är ofta en förutsättning för anställda när de utför sina arbetsuppgifter. IT-systemen kan även vara en förutsättning för automatisering av en organisations verksam-hets- och produktionsprocesser. I takt med ökad IT-användning blir det allt vikti-gare för organisationer att få ut ett högre värde av sina IT-investeringar. IT-system bör därför kontinuerligt utvecklas för att skapa fortsatt god nytta för användare. Utveckling av IT-system kan bedrivas i projekt som arbetsform. När projektorgani-sationer ska avslutas överlämnas resultatet till en förvaltningsorganisation för för-valtning och fortsatt vidareutveckling. Denna avhandling är en studie avseende projekt- och förvaltningsuppdrag av IT-system. Dess övergripande syfte är att bidra till en fördjupad förståelse för hur överlämning från en projektorganisation till en förvaltningsorganisation kan genomföras. En central utgångspunkt har varit att frilägga överlämningen och därmed studera överlämningen i sig och inte som en specifik aktivitet i ett projekt. Två fallstudier har genomförts i två svenska organisationer, vid ett landsting och vid ett försäkringsbolag. För respektive organisation har jag studerat överläm-ningen från ett utvecklingsprojekt till en förvaltningsorganisation genom intervju-er och observationer samt studier av sekundära data. För organisering och presen-tation av de enskilda fallen, dvs. den friläggande tolkningen, har jag tillämpat nar-rativ analys. För den tilldelande tolkningen har jag tillämpat teorigenerering på empirisk grund. Studiens bidrag är begreppsbildande och jag definierar begreppet ”överläm-ningsarena”. För överlämningsarenan identifierar och beskriver jag involverade aktörer, aktiviteter som utförs samt vad som överlämnas. Ett centralt bidrag är även identifierandet och beskrivandet av den kontext som omfattar en överläm-ningsarena. Vidare är bidraget normativt, jag ger råd och riktlinjer för hur en över-lämning bör genomföras.
53

A STUDY ON THE IMPACTS OF RMB EXCHANGE RATE FLUCTUATIONS ON ENTERPRISES’ CROSS-BORDER M&AS

Huang, Yuhui, 0000-0002-1203-1512 January 2021 (has links)
Do renminbi (RMB) exchange rate fluctuations affect cross-border M&A activities of enterprises at the micro level? This paper centers on this major issue, and we study and analyze the impacts of RMB internationalization on the magnitude and success of cross-border M&As. We investigate the impacts of exchange rate changes on the magnitude and success of enterprise-level cross-border M&As by developing nominal exchange rate (NER) and real exchange rate (RER) volatility indicators using data from the Thomson Financial SDC Platinum Merger and Acquisitions database. By applying a variety of indicators and subsample estimates in the study, we find that exchange rate volatility (of either NER or RER) is significantly negatively correlated with enterprise-level cross-border M&As, suggesting that RMB exchange rate movements deter cross-border M&As to some extent; fluctuations in RMB exchange rate have a significant negative impact on the success of cross-border M&As, and the exchange rate risk induced by exchange rate changes increases the risk of cross-border M&As; meanwhile, exchange rate fluctuations have a significant inhibitory effect on conglomerate M&As in addition to horizontal cross-border M&As. In addition, exchange rate fluctuations have a significant inhibitory effect on the profit-oriented cross-border M&As of enterprises in non-state-owned-or-controlled industries. Therefore, we should take prudent actions to prevent the impacts of RMB exchange rate movements on cross-border M&As, actively tap the potential of bilateral investment treaties in securing cross-border M&As, promote coordination between RMB exchange rate regulation iimechanisms and the “go global” strategy, and improve the level of internationalization and competitiveness of Chinese enterprises. / Business Administration/Finance
54

Anemone: a Visual Semantic Graph

Ficapal Vila, Joan January 2019 (has links)
Semantic graphs have been used for optimizing various natural language processing tasks as well as augmenting search and information retrieval tasks. In most cases these semantic graphs have been constructed through supervised machine learning methodologies that depend on manually curated ontologies such as Wikipedia or similar. In this thesis, which consists of two parts, we explore in the first part the possibility to automatically populate a semantic graph from an ad hoc data set of 50 000 newspaper articles in a completely unsupervised manner. The utility of the visual representation of the resulting graph is tested on 14 human subjects performing basic information retrieval tasks on a subset of the articles. Our study shows that, for entity finding and document similarity our feature engineering is viable and the visual map produced by our artifact is visually useful. In the second part, we explore the possibility to identify entity relationships in an unsupervised fashion by employing abstractive deep learning methods for sentence reformulation. The reformulated sentence structures are qualitatively assessed with respect to grammatical correctness and meaningfulness as perceived by 14 test subjects. We negatively evaluate the outcomes of this second part as they have not been good enough to acquire any definitive conclusion but have instead opened new doors to explore. / Semantiska grafer har använts för att optimera olika processer för naturlig språkbehandling samt för att förbättra sökoch informationsinhämtningsuppgifter. I de flesta fall har sådana semantiska grafer konstruerats genom övervakade maskininlärningsmetoder som förutsätter manuellt kurerade ontologier såsom Wikipedia eller liknande. I denna uppsats, som består av två delar, undersöker vi i första delen möjligheten att automatiskt generera en semantisk graf från ett ad hoc dataset bestående av 50 000 tidningsartiklar på ett helt oövervakat sätt. Användbarheten hos den visuella representationen av den resulterande grafen testas på 14 försökspersoner som utför grundläggande informationshämtningsuppgifter på en delmängd av artiklarna. Vår studie visar att vår funktionalitet är lönsam för att hitta och dokumentera likhet med varandra, och den visuella kartan som produceras av vår artefakt är visuellt användbar. I den andra delen utforskar vi möjligheten att identifiera entitetsrelationer på ett oövervakat sätt genom att använda abstraktiva djupa inlärningsmetoder för meningsomformulering. De omformulerade meningarna utvärderas kvalitativt med avseende på grammatisk korrekthet och meningsfullhet såsom detta uppfattas av 14 testpersoner. Vi utvärderar negativt resultaten av denna andra del, eftersom de inte har varit tillräckligt bra för att få någon definitiv slutsats, men har istället öppnat nya dörrar för att utforska.
55

Etude du rôle de la réponse UV sur le contrôle de la réparation par excision de nucléotides (NER) des dommages à l’ADN : rôle des voies MAPK et de l’ADN polymérase eta

Rouget, Raphaël 05 1900 (has links)
La réponse cellulaire aux ultra-violets (UV), ou réponse UV, est une réponse complexe et spécialisée dans l’adaptation et la tolérance des dommages aux UV. Celle-ci est initiée par un grand nombre d’évènements moléculaires et de signalisation nucléaire mais aussi au niveau de la membrane plasmique ou du cytoplasme. L’importance et l’influence exactes de ces évènements sur la réparation par excision de nucléotides (NER) des dommages UV à l’ADN sont encore mal comprises et doivent encore être méthodiquement démontrées. Dans cette thèse, grâce à l’utilisation d’une méthode sensible d’analyse de la réparation NER basée sur la cytométrie en flux, il est montré, dans un premier temps, que l’activité des voies MAPK (Mitogen-Activated Protein Kinases), qui sont des voies de signalisation de stress UV d’origine cytoplsamique, ne participent pas à l’efficacité de réparation NER des dommages UV dans les cellules humaines. En effet, l’abrogation de la signalisation MAPK, par inhibition pharmacologique, par utilisation de mutants dominant-négatifs ou par inhibition de leur expression endogène, ne révèlent aucun changement de la cinétique de réparation des dommages UV par excision de nucléotides. Cependant, l’utilisation de cette même méthode de réparation, mais cette fois, appliquée pour l’étude de réparation NER en fonction du cycle cellulaire, a permis de mettre en évidence la nécessité fonctionnelle de l’ADN polymérase translésionnelle eta (Pol η) dans la réparation NER des dommages UV, uniquement en phase S. Cette observation fut initialement caractérisée dans les cellules de patients affectés du syndrome variant de xérodermie pigmentaire (XP-V) puis, confirmée ensuite par l’inhibition de l’expression de Pol η endogène ou par la complémentation avec des mutants non-fonctionnels dans les cellules XP-V. Ces résultats indiquent que, contrairement à la réponse UV MAPK cytoplasmique, les évènements nucléaires comme la synthèse translésionnelle, peuvent influencer l’efficacité de réparation NER en phase S. Plus particulièrement, ces données établissent un lien possible entre la réparation NER en phase S et les niveaux de stress réplicatifs, révélé ici par la déficience fonctionnelle Pol η ou ATR. Les observations, présentées dans cette thèse, renforcent un rôle du point de contrôle S aux UV sur l’efficacité de la réparation NER et suggèrent que l’inhibition NER, observée en phase S dans les cellules XP-V, est modulée par le stress réplicatif. Un tel moyen de contrôle pourrait avoir une action plutôt protectrice pendant cette phase critique du cycle cellulaire. Mots clés: UV, translésionnelle, eta, MAPK, NER, CPD, cytométrie, phase-S, tolérance. / The UV-response is a complex cellular response to UV irradiation, which allows cellular adaptation and protection against deleterious effects of UV. This specialized response involves numerous molecular and signaling events from plasma membrane and from the nucleus represented, among others, by Mitogen-Activated Protein Kinase (MAPK) pathway activation and translesion synthesis respectively. More particularly, the exact role of these events on the removal UV-induced DNA damage by nucleotide excision repair (NER) in human cells is poorly understood and documented. By using a sensitive flow cytometry based-NER assay, presented and validated in this thesis, to quantify the removal of UV-DNA damage, it was unexpectedly found that Mitogen-Activated Protein Kinase (MAPK) signalling, originating from the the plasma membrane, does not regulate the efficiency of UV-induced DNA damage repair in human cells. Indeed, MAPK inhibition with pharmacological inhibitors, expression of short-hairpin RNA or dominant negative mutant, all together, substantiate fully the lack of effect of this signalling pathway on UV-damage removal by NER in human primaries and tumorous cells. Surprisingly, the same NER assay, applied to quantify the removal of UV-induced DNA damages as a function of the cell cycle, has shown a requirement of functional translesion synthesis polymerase eta (Pol η) for efficient UV-DNA damage repair in human cells uniquely during S-phase, where its function is required for the bypass of UV DNA damage. This observation, originally made in fibroblasts from xeroderma pigmentosum variant syndrome (XP-V) afflicted patients, was further confirmed in normal human cells, by abrogation of endogenous Pol η expression or by complementation with Pol η in XP-V cells. All together, the data presented here, indicate that MAPK signaling play no role in NER-mediated UV-damage removal, but highlight a role for UV-DNA damage tolerance response, as translesion synthesis, in regulation of NER efficiency. More particularly, these observations establish a potential link between the S-Phase Repair (SPR) of UV-DNA damages and replicative stress, revealed by a deficiency of Pol η or ATR. This SPR defects seen under acute replicative stress conditions could impact tumorogenesis or chemotherapy outcomes. Moreover, SPR defects, seen in XP-V cells could be controlled by replicative stress, and also reflect a protective coordination to reduce high risks of genetic or chromosomal aberrations that may occur during DNA replication upon UV exposure. Key Words: Translesion, UV, TLS, eta, MAPK, NER, S-phase, flow-cytometry, CPD.
56

Avaliação do dano de DNA em pacientes pediátricos com leucemia linfoide aguda durante a terapia de indução

Santos, Rafael Pereira dos January 2016 (has links)
O câncer é a primeira causa de mortes por doença, após 1 ano de idade, até o final da adolescência, excetuando aquelas relacionadas aos acidentes e à violência. A Leucemia Linfoide Aguda (LLA) afeta células linfoides e agrava-se rapidamente. São os tumores mais frequentes na infância e representam um terço de todas as neoplasias malignas nesta faixa etária. Em média, a taxa de cura excede 70%, todavia, apesar dos avanços das últimas décadas, os índices de crianças que apresentam recidiva da doença continua significativo. Danos endógenos ao DNA ocorrem numa frequência altíssima, além dos danos causados por terapias antitumorais. Alteração no reparo ao dano do DNA pode induzir mecanismos de resistência ao tratamento quimioterápico, resultando em aumento do reparo de lesões do DNA. Reparo por Excisão de Nucleotídeos (NER) é a via de reparo de DNA mais versátil e flexível nas células. Seus componentes estão sendo estudados como biomarcadores de prognóstico e terapias-alvo. No entanto, alguns relatórios têm abordado danos de DNA em Leucemia Linfoide Aguda (LLA) pediátrica. Neste estudo, realizamos um estudo de acompanhamento observacional em pacientes pediátricos para avaliar os danos do DNA pelo Ensaio Cometa Alcalino e expressão gênica da via de NER durante a indução da quimioterapia. Amostras de medula óssea (MO) ao diagnóstico, dia 15 (D15) e 30 (D30) do tratamento foram coletadas de 28 pacientes com LLA. Não houve aumento no índice de dano. No entanto, houve uma redução de células com baixo danos na comparação do D35 com o diagnóstico. Este resultado se confirmou em pacientes que apresentaram doença residual mínima positiva. A via de NER permaneceu constante, no entanto, em um único paciente, foi observada uma diminuição significativa da expressão dos genes, talvez devido ao silenciamento ou a regulação negativa das vias de reparo. Níveis de danos e reparação do DNA podem influenciar o resultado clínico, estar envolvidos na resistência aos fármacos e potencializar o risco de recidiva. Este é o primeiro estudo que avalia o dano ao DNA em amostras de MO de pacientes pediátricos com LLA. Apesar do pequeno número de pacientes alocados para o estudo, a partir dos achados é possível concluir que complexos de reparo merecem ser investigados a curto e a longo prazo. Acompanhamento dos resultados do paciente vai ajudar a elucidar a implicação dos nossos achados em taxas de cura e de recidiva. / Cancer is the leading cause of death by disease after 1 year old until the end of adolescence, except those related to accidents and violence. Acute Lymphoid Leukemia (ALL) affects lymphoid cells and worsens quickly. They are the most frequent tumors in childhood and account for a third of all malignancies in this age group. On average, the cure rate exceeds 70%, however, despite the progress of recent decades, rates of children with disease recurrence remains significant. Endogenous DNA damage occurs at a very high frequency, in addition to the damage caused by anti-tumor therapies. Change in the repair of DNA damage can induce resistance mechanisms to chemotherapy, resulting in increased repair of DNA lesions. Nucleotide Excision Repair (NER) pathway is the more versatile and flexible DNA repair in cells. Its components are being studied as prognostic biomarkers and targeted therapies. However, there are some reports of DNA damage in pediatric Acute Lymphoid Leukemia (ALL). In this study, we conducted an observational follow-up study in pediatric patients to assess DNA damage by alkaline comet assay and gene expression of NER pathway during induction chemotherapy. Bone marrow (BM) samples at diagnosis, 15th (D15) and 30th (D30) of treatment were collected from 28 patients with ALL. There was no increase in damage index. However, there was a reduction of cells with low damage in comparison to the D35 diagnosis. This result was confirmed in patients with positive minimal residual disease. The NER pathway remained constant, however, in one patient, a significant decrease of gene expression was observed perhaps due to the silencing or down-regulation of repair pathways. Damage levels and DNA repair can influence the clinical result and may be involved in drug resistance and enhance the risk of recurrence. This is the first study to assess DNA damage in BM samples of pediatric patients with ALL. Despite the small number of patients allocated to the study, from the findings we conclude that repair complex deserves to be investigated in the short and long term. Monitoring patient’s outcomes will help to access the implication of our findings in cure and relapse rates.
57

LES PROTEINES KIN17, XPC, DNA-PKCS ET XRCC4 DANS LA REPONSE CELLULAIRE AUX DOMMAGES DE L'ADN. ETUDE DES RELATIONS ENTRE LA REPARATION PAR EXCISION DE NUCLEOTIDES ET LA RECOMBINAISON NON HOMOLOGUE DANS UN MODELE SYNGENIQUE HUMAIN

Despras, Emmanuelle 26 October 2006 (has links) (PDF)
La réponse au stress génotoxique met en jeu de nombreux facteurs cellulaires impliqués dans un réseau complexe de mécanismes visant à assurer le maintien de l'intégrité génétique de l'organisme. Ces mécanismes incluent la détection et la réparation des lésions de l'ADN, la régulation de la transcription et de la réplication et le déclenchement éventuel de la mort cellulaire. Parmi les protéines nucléaires participant à cette réponse, les protéines kin17 sont des protéines à doigt de zinc conservées au cours de l'évolution et activées par les ultraviolets (UV) et les radiations ionisantes (RI). Nous avons montré que la protéine kin17 humaine (HSAkin17) est présente dans la cellule sous une forme soluble et sous une forme ancrée aux structures nucléaires. Une fraction de la protéine HSAkin17 est directement associée à la chromatine. La protéine HSAkin17 est recrutée sur les structures nucléaires 24 heures après traitement par différents agents induisant des cassures double-brin de l'ADN (DSB) et/ou un blocage des fourches de réplication. Par ailleurs, la réduction du niveau total de protéine HSAkin17 sensibilise les cellules RKO aux RI. Nous présentons également des résultats impliquant la protéine HSAkin17 dans la réplication de l'ADN. Cette hypothèse a été confirmée par la démonstration biochimique de son appartenance au complexe de réplication. La protéine HSAkin17 pourrait donc assurer le lien entre réplication et réparation de l'ADN, un défaut de la voie HSAkin17 entraînant une augmentation de la radiosensibilité. Dans un deuxième temps, nous avons étudié les interactions entre deux mécanismes de réparation de l'ADN : la réparation par excision de nucléotides (NER) et la recombinaison non homologue (NHEJ). Le NER prend en charge une grande variété de lésions provoquant une distortion de la double hélice d'ADN dont les dimères de pyrimidines induits par les UV. Le NHEJ assure la réparation des DSB par jonction directe des extrémités d'ADN. Nous avons utilisé un modèle syngénique de défaut de la réparation basé sur l'interférence ARN développé au laboratoire. En effet, les vecteurs dérivés du virus d'Epstein-Barr (pEBV) permettent l'expression à long terme de siRNA et l'extinction spécifique du gène cible. La réduction de l'expression de gènes impliqués dans le NER (XPA et XPC) ou le NHEJ (DNA-PKcs et XRCC4) entraîne les phénotypes attendus. Nous avons montré que la réduction du niveau de protéine XPC sensibilise les cellules HeLa à l'étoposide, un inhibiteur de la topoisomérase II qui induit des DBS, et affecte leur activité NHEJ in vitro. Ces résultats suggèrent que la protéine XPC pourrait être requise pour la réparation de certains types de cassures ou participer à un système global de régulation de la réponse cellulaire aux lésions de l'ADN. Notre modèle ouvre donc des perspectives intéressantes pour l'étude des relations entre les différentes voies de réparation de l'ADN dans des cellules humaines.
58

Serviceorientiertes Text Mining am Beispiel von Entitätsextrahierenden Diensten

Pfeifer, Katja 08 September 2014 (has links) (PDF)
Der Großteil des geschäftsrelevanten Wissens liegt heute als unstrukturierte Information in Form von Textdaten auf Internetseiten, in Office-Dokumenten oder Foreneinträgen vor. Zur Extraktion und Verwertung dieser unstrukturierten Informationen wurde eine Vielzahl von Text-Mining-Lösungen entwickelt. Viele dieser Systeme wurden in der jüngeren Vergangenheit als Webdienste zugänglich gemacht, um die Verwertung und Integration zu vereinfachen. Die Kombination verschiedener solcher Text-Mining-Dienste zur Lösung konkreter Extraktionsaufgaben erscheint vielversprechend, da so bestehende Stärken ausgenutzt, Schwächen der Systeme minimiert werden können und die Nutzung von Text-Mining-Lösungen vereinfacht werden kann. Die vorliegende Arbeit adressiert die flexible Kombination von Text-Mining-Diensten in einem serviceorientierten System und erweitert den Stand der Technik um gezielte Methoden zur Auswahl der Text-Mining-Dienste, zur Aggregation der Ergebnisse und zur Abbildung der eingesetzten Klassifikationsschemata. Zunächst wird die derzeit existierende Dienstlandschaft analysiert und aufbauend darauf eine Ontologie zur funktionalen Beschreibung der Dienste bereitgestellt, so dass die funktionsgesteuerte Auswahl und Kombination der Text-Mining-Dienste ermöglicht wird. Des Weiteren werden am Beispiel entitätsextrahierender Dienste Algorithmen zur qualitätssteigernden Kombination von Extraktionsergebnissen erarbeitet und umfangreich evaluiert. Die Arbeit wird durch zusätzliche Abbildungs- und Integrationsprozesse ergänzt, die eine Anwendbarkeit auch in heterogenen Dienstlandschaften, bei denen unterschiedliche Klassifikationsschemata zum Einsatz kommen, gewährleisten. Zudem werden Möglichkeiten der Übertragbarkeit auf andere Text-Mining-Methoden erörtert.
59

Automatic Identification of Duplicates in Literature in Multiple Languages

Klasson Svensson, Emil January 2018 (has links)
As the the amount of books available online the sizes of each these collections are at the same pace growing larger and more commonly in multiple languages. Many of these cor- pora contain duplicates in form of various editions or translations of books. The task of finding these duplicates is usually done manually but with the growing sizes making it time consuming and demanding. The thesis set out to find a method in the field of Text Mining and Natural Language Processing that can automatize the process of manually identifying these duplicates in a corpora mainly consisting of fiction in multiple languages provided by Storytel. The problem was approached using three different methods to compute distance measures between books. The first approach was comparing titles of the books using the Levenstein- distance. The second approach used extracting entities from each book using Named En- tity Recognition and represented them using tf-idf and cosine dissimilarity to compute distances. The third approach was using a Polylingual Topic Model to estimate the books distribution of topics and compare them using Jensen Shannon Distance. In order to es- timate the parameters of the Polylingual Topic Model 8000 books were translated from Swedish to English using Apache Joshua a statistical machine translation system. For each method every book written by an author was pairwise tested using a hypothesis test where the null hypothesis was that the two books compared is not an edition or translation of the others. Since there is no known distribution to assume as the null distribution for each book a null distribution was estimated using distance measures of books not written by the author. The methods were evaluated on two different sets of manually labeled data made by the author of the thesis. One randomly sampled using one-stage cluster sampling and one consisting of books from authors that the corpus provider prior to the thesis be considered more difficult to label using automated techniques. Of the three methods the Title Matching was the method that performed best in terms of accuracy and precision based of the sampled data. The entity matching approach was the method with the lowest accuracy and precision but with a almost constant recall at around 50 %. It was concluded that there seems to be a set of duplicates that are clearly distin- guished from the estimated null-distributions, with a higher significance level a better pre- cision and accuracy could have been made with a similar recall for the specific method. For topic matching the result was worse than the title matching and when studied the es- timated model was not able to create quality topics the cause of multiple factors. It was concluded that further research is needed for the topic matching approach. None of the three methods were deemed be complete solutions to automatize detection of book duplicates.
60

Avaliação do dano de DNA em pacientes pediátricos com leucemia linfoide aguda durante a terapia de indução

Santos, Rafael Pereira dos January 2016 (has links)
O câncer é a primeira causa de mortes por doença, após 1 ano de idade, até o final da adolescência, excetuando aquelas relacionadas aos acidentes e à violência. A Leucemia Linfoide Aguda (LLA) afeta células linfoides e agrava-se rapidamente. São os tumores mais frequentes na infância e representam um terço de todas as neoplasias malignas nesta faixa etária. Em média, a taxa de cura excede 70%, todavia, apesar dos avanços das últimas décadas, os índices de crianças que apresentam recidiva da doença continua significativo. Danos endógenos ao DNA ocorrem numa frequência altíssima, além dos danos causados por terapias antitumorais. Alteração no reparo ao dano do DNA pode induzir mecanismos de resistência ao tratamento quimioterápico, resultando em aumento do reparo de lesões do DNA. Reparo por Excisão de Nucleotídeos (NER) é a via de reparo de DNA mais versátil e flexível nas células. Seus componentes estão sendo estudados como biomarcadores de prognóstico e terapias-alvo. No entanto, alguns relatórios têm abordado danos de DNA em Leucemia Linfoide Aguda (LLA) pediátrica. Neste estudo, realizamos um estudo de acompanhamento observacional em pacientes pediátricos para avaliar os danos do DNA pelo Ensaio Cometa Alcalino e expressão gênica da via de NER durante a indução da quimioterapia. Amostras de medula óssea (MO) ao diagnóstico, dia 15 (D15) e 30 (D30) do tratamento foram coletadas de 28 pacientes com LLA. Não houve aumento no índice de dano. No entanto, houve uma redução de células com baixo danos na comparação do D35 com o diagnóstico. Este resultado se confirmou em pacientes que apresentaram doença residual mínima positiva. A via de NER permaneceu constante, no entanto, em um único paciente, foi observada uma diminuição significativa da expressão dos genes, talvez devido ao silenciamento ou a regulação negativa das vias de reparo. Níveis de danos e reparação do DNA podem influenciar o resultado clínico, estar envolvidos na resistência aos fármacos e potencializar o risco de recidiva. Este é o primeiro estudo que avalia o dano ao DNA em amostras de MO de pacientes pediátricos com LLA. Apesar do pequeno número de pacientes alocados para o estudo, a partir dos achados é possível concluir que complexos de reparo merecem ser investigados a curto e a longo prazo. Acompanhamento dos resultados do paciente vai ajudar a elucidar a implicação dos nossos achados em taxas de cura e de recidiva. / Cancer is the leading cause of death by disease after 1 year old until the end of adolescence, except those related to accidents and violence. Acute Lymphoid Leukemia (ALL) affects lymphoid cells and worsens quickly. They are the most frequent tumors in childhood and account for a third of all malignancies in this age group. On average, the cure rate exceeds 70%, however, despite the progress of recent decades, rates of children with disease recurrence remains significant. Endogenous DNA damage occurs at a very high frequency, in addition to the damage caused by anti-tumor therapies. Change in the repair of DNA damage can induce resistance mechanisms to chemotherapy, resulting in increased repair of DNA lesions. Nucleotide Excision Repair (NER) pathway is the more versatile and flexible DNA repair in cells. Its components are being studied as prognostic biomarkers and targeted therapies. However, there are some reports of DNA damage in pediatric Acute Lymphoid Leukemia (ALL). In this study, we conducted an observational follow-up study in pediatric patients to assess DNA damage by alkaline comet assay and gene expression of NER pathway during induction chemotherapy. Bone marrow (BM) samples at diagnosis, 15th (D15) and 30th (D30) of treatment were collected from 28 patients with ALL. There was no increase in damage index. However, there was a reduction of cells with low damage in comparison to the D35 diagnosis. This result was confirmed in patients with positive minimal residual disease. The NER pathway remained constant, however, in one patient, a significant decrease of gene expression was observed perhaps due to the silencing or down-regulation of repair pathways. Damage levels and DNA repair can influence the clinical result and may be involved in drug resistance and enhance the risk of recurrence. This is the first study to assess DNA damage in BM samples of pediatric patients with ALL. Despite the small number of patients allocated to the study, from the findings we conclude that repair complex deserves to be investigated in the short and long term. Monitoring patient’s outcomes will help to access the implication of our findings in cure and relapse rates.

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