• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 266
  • 107
  • 49
  • 12
  • 8
  • 7
  • 5
  • 4
  • 4
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 549
  • 345
  • 324
  • 124
  • 86
  • 72
  • 70
  • 53
  • 53
  • 44
  • 43
  • 43
  • 41
  • 41
  • 39
  • 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.
321

Determinants of group splitting: an examination of environmental, demographic, genealogical and state-dependent factors of matrilineal fission in a threatened population of fish-eating killer whales (Orcinus orca)

Stredulinsky, Eva Helene 12 October 2016 (has links)
Group living is a social strategy adopted by many species, where individuals can exhibit long-term social affiliation with others, strengthened through cooperative behaviour and often kinship. For highly social mammals, changes in group membership may have significant consequences for the long-term viability and functioning of a population. Detecting significant social events is essential for monitoring the social dynamics of such populations and is crucial to determining the factors underlying these events. Detecting when changes in social organization occur, especially with incomplete data, poses significant analytical challenges. To resolve this issue, I developed and assessed a straightforward, multi-stage and generalizable method with broad utility for ecologists interested in detecting and subsequently investigating causes of changes in social organization. My approach illustrates the frequency and ecological relevance of group fission and fusion events in a population of fish-eating ‘Resident’ killer whales (Orcinus orca). Group fission is a process commonly found in social mammals, yet is poorly described in many taxa, and has never been formally described in killer whales. To address this gap, I provided the first description of matrilineal fission in killer whales, from a threatened but growing Northern Resident killer whale population in which matrilineal fission has been observed for the past three decades. I also undertook the first comprehensive assessment of how killer whale intragroup cohesion is influenced by group structure, demography and resource abundance. Fission in Northern Resident killer whales occurred both along and across maternal lines, where animals dispersed in parallel with their closest maternal kin. I show that fission in this population is driven primarily by population growth and the demographic conditions of groups, particularly those dictating the nutritional requirements of the group. I posit that intragroup food competition is the most likely explanation for group fission in this population, where prey abundance also has ancillary effects. As group fission can have a direct impact on the fitness of group members and the long-term viability of a population, my findings underscore the importance of incorporating studies of sociality into the management of threatened populations of social mammals. / Graduate / 0329 / 0472
322

Células natural killer em uma coorte de pacientes com artrite reumatóide tratados com rituximabe

Garcia, Mariana Pires January 2013 (has links)
OBJETIVOS: Avaliar o perfil e o número absoluto e percentual de células NK verdadeiras (CD56+CD16+CD3-) e de células NK e NKT (CD56+) no sangue periférico de uma coorte de pacientes com artrite reumatóide (AR) antes e durante o tratamento com rituximabe (RTX). MÉTODOS: Foram analisados dez pacientes do grupo controle (doadores de sangue) e dez pacientes com AR que receberam duas infusões de RTX 1g separadas por intervalo de 14 dias. As análises imunofenotípicas para avaliação do perfil e quantificação de células NK foram realizadas pré e após a infusão ou até a recaída clínica. Pacientes respondedores e não respondedores foram classificados de acordo com os critérios do Colégio Americano de Reumatologia (ACR) em 6 meses. RESULTADOS: A quantidade de células NK verdadeiras não demonstrou variação significativa pré e após o tratamento com RTX. Contudo, houve aumento percentual de células CD56+ entre o primeiro e o segundo mês após a infusão com RTX. Além disso, os pacientes respondedores apresentaram uma tendência de aumento do número absoluto de células NK verdadeiras após dois meses de tratamento. Já em relação ao grupo controle, observou-se um aumento significativo do número de células NK basais nos pacientes com AR (p<0,05). CONCLUSÕES: Foi identificada uma tendência de aumento nos valores absolutos de células NK verdadeiras entre os pacientes respondedores no segundo mês após a infusão com RTX. Não foi identificada uma variação significativa no perfil e quantidade de células NK nos pacientes com AR pré e após o tratamento com RTX. Contudo, foi observado que os pacientes com AR possuem uma quantidade maior de células NK do que os controles, sugerindo um possível envolvimento destas células na AR. / OBJECTIVES: To assess the profile as well as the absolute number and percentage of true NK cells (CD56+CD16+CD3-), and NK and NKT cells (CD56+) in the peripheral blood of a cohort of patients with rheumatoid arthritis (RA) before and during rituximab (RTX) therapy. METHODS: Ten control patients (blood donors) and ten patients with RA were assessed. The latter group received two intravenous infusions of 1g RTX, separated by a 14 day interval. Immunophenotypic analyses of NK cells were conducted before and after infusion, or until clinical relapse. After six months, respondents and nonrespondents were reassessed according to American Rheumatology Criteria (ARC). RESULTS: The number of true NK cells did not significantly change after treatment with RTX. However, an increase in the percentage of CD56+ cells was observed between the first and second month after RTX infusion. Respondents also displayed a tendency toward an increased number of true NK cells after two months of treatment. At baseline, the number of NK cells was also found to be significantly higher in patients with RA than in control individuals (p<0.05). CONCLUSIONS: Respondents displayed a tendency toward an increase in the absolute number of true NK cells in the second month after RTX infusion. No significant changes in the profile and frequency of NK cells were found between preand post-RTX treatment assessments of patients with RA. However, it was found that patients with RA have a higher number of NK cells than control partcipants, suggesting a possible role of these cells in RA.
323

Avaliação da interação entre células dendríticas e células "Natural Killer" (CD56+) na resposta ao Paracoccidioides brasiliensis / Evaluation of the crosstalk between dendritics cells and natural killer (CD56+) in response to Paracoccidioides brasiliensis

Longhi, Larissa Nara Alegrini, 1982- 26 August 2018 (has links)
Orientadores: Ronei Luciano Mamoni, Maria Heloisa Souza Lima Blotta / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T10:53:12Z (GMT). No. of bitstreams: 1 Longhi_LarissaNaraAlegrini_D.pdf: 4091504 bytes, checksum: 149e4a062c177377d07fb66598d14e85 (MD5) Previous issue date: 2014 / Resumo: Pesquisas recentes têm demonstrado a importância da resposta imune inata no controle da resposta adaptativa. Em estudo anterior pudemos demonstrar que as células Natural Killer (NK) participam da resposta imunológica ao Paracoccidioides brasiliensis, agente etiológico da Paracoccidioidomicose (PCM). Atualmente sabe-se que células dendríticas (DCs) são capazes de interagir com células NK, aumentando a sua atividade. O objetivo deste trabalho foi avaliar o mecanismo utilizado pelas células NK no reconhecimento de células leveduriformes de P. brasiliensis e, se DCs estimuladas pelo fungo são capazes de interagir com células NK e por conseguinte influenciar a diferenciação de linfócitos T. Foram utilizadas DCs derivadas de monócitos e células CD56+ (NK) isoladas do sangue periférico de indivíduos saudáveis. A análise do papel dos receptores do tipo toll (TLR-2 e TLR-4) e do receptor de complemento 3 (CR3 - CD11b) no reconhecimento do P. brasiliensis pelas células NK demonstrou que este último receptor é provavelmente mais importante, uma vez que o seu bloqueio diminuiu a ativação e a atividade citotóxica direta das células NK contra o fungo. Enquanto que o TLR2, em conjunto com o CR3 leva à produção de citocinas como IFN-gama e TNF-alfa. Além disso, nossos resultados demonstraram que DCs estimuladas com o fungo são ativadas e produzem citocinas importantes para a ativação de células NK (IL-12, IL-18, IL-23 e IL-15). Células NK estimuladas com essas citocinas ou cocultivadas com DCs (previamente estimuladas com leveduras do fungo) apresentam maior capacidade de proliferação, aumento na expressão de marcadores de ativação (CD25 e CD69), aumento na capacidade fungicida e aumento da produção de citocinas como IFN-gama e TNF-alfa. Esses efeitos foram parcialmente dependentes de contato, provavelmente envolvendo a participação de IL-15 associada à membrana das DCs, e também à produção de citocinas solúveis (IL-12, IL-23 e IL-18) pelas DCs. Por outro lado, a interação entre células NK e DCs leva estas últimas a aumentarem a expressão de moléculas coestimulatórias (CD80 e CD86) e de moléculas de MHC de classe II, importantes para a apresentação de antígenos aos linfócitos T. Também pudemos observar que a interação entre DCs estimuladas com células leveduriformes de P. brasiliensis e células NK levam a diferenciação de linfócitos T CD4+ e T CD8+ produtores de IFN-gama, ao mesmo tempo inibindo a diferenciação de linfócitos T produtores de IL-4. Em conjunto nossos resultados demonstraram que a interação entre DCs e células NK estimuladas com células leveduriformes de P. brasiliensis leva a um aumento tanto da ativação das DCs quanto das células NK, e que essa interação pode ser importante para modular a resposta imunológica adquirida subsequente / Abstract: Several studies have shown that the innate immune response presents a fundamental role in controlling the adaptive immune response. In a previous study we demonstrated that natural killer cells (NK) participate in the immune response to Paracoccidioides brasiliensis, the etiological agent of paracoccidioidomycosis (PCM). Currently it is known that dendritic cells (DCs) are able to interact with NK cells, increasing its activity. The objective of this study was to evaluate the mechanism used by NK cells in the recognition of P. brasiliensis yeast cells and, whether DCs stimulated by the fungus are able to interact with NK cells and therefore influence the differentiation of T lymphocytes. We used DCs derived from monocytes and CD56 + (NK) cells isolated from peripheral blood of healthy individuals. We analyzed the role of some toll-like receptors (TLR-2 and TLR-4) and the complement receptor 3 (CR3 - CD11b) in the recognition of P. brasiliensis NK cells. Our results showed that the CR3 is probably more important, since that its blockage decreased the activation and the direct cytotoxic activity of NK cells against the fungus. Furthermore, activation via TLR2, together with CR3, leads to the production of cytokines such as IFN-gamma and TNF-alpha. Moreover, our results demonstrated that DCs stimulated with the fungus are activated and produce cytokines important for the activation of NK cells (IL-12, IL-18, IL-23 and IL-15). NK cells stimulated with these cytokines or co-cultured with DCs (previously stimulated with yeast cells) presented greater capacity for proliferation, increased expression of activation markers (CD25 and CD69), increased fungicide capacity and increased production of cytokines such as IFN-gamma and TNF-alpha. These effects were partially dependent on contact, probably involving the participation of membrane associated IL-15, and also the production of soluble cytokines (IL-12, IL-23 and IL-18) by DCs. In addition, the interaction between NK cells and DCs leads to an increased expression of molecules important for the antigen presentation to T cells, such as costimulatory molecules (CD80 and CD86) and class II MHC on DCs. We also observed that the interaction between DCs (stimulated with the fungus) and NK cells increased the differentiation of T CD4+ and T CD8+ cells into IFN-gamma producing lymphocytes, while inhibited the differentiation of IL-4 producing T lymphocytes. Altogether our results demonstrate that the crosstalk between DCs and NK cells stimulated with P. brasiliensis yeast cells leads to an increased activation of both DCs and NK cells, and that this interaction can be important for modulating the subsequent acquired immune response against the fungus / Doutorado / Ciencias Biomedicas / Doutora em Ciências Médicas
324

iPSC-derived platelets depleted of HLA class-I are inert to anti-HLA class-I and NK cell immunity / HLAクラスIを欠失させたiPS細胞由来血小板は、抗HLAクラスI抗体とNK細胞による免疫機構を回避する

Suzuki, Daisuke 25 May 2020 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医科学) / 甲第22648号 / 医科博第111号 / 新制||医科||7(附属図書館) / 京都大学大学院医学研究科医科学専攻 / (主査)教授 生田 宏一, 教授 竹内 理, 教授 髙折 晃史 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
325

Gab3 is Required for IL 2 and IL 15 Induced NK Cell Proliferation and is a Key Determinate for Tumor Clearance and Controlling Trophoblast Invasion

Sliz, Anna January 2019 (has links)
No description available.
326

A natural killer cell-centric approach toward new therapeutics for autoimmune disease.

Reighard, Seth D. 10 October 2019 (has links)
No description available.
327

Role de l'autophagie dans la réponse immunitaire anti-tumorale des cellules NK / The Role of Autophagy on Anti-Tumor Immune Response Mediated by Natural Killer Cells

Mgrditchian, Takouhie 26 June 2017 (has links)
Les cellules Natural Killer (NK) sont des effecteurs de l’immunité innée qui jouent un rôle important dans la surveillance immunitaire anti-tumorale. Le concept d’immunothérapie basée sur l’activation des cellules NK a ainsi émergé comme une approche thérapeutique convaincante. Malgré les avancées spectaculaires réalisées ces dernières décennies, les connaissances concernant la biologie des cellules NK restent largement fragmentées. La mise en place de stratégies thérapeutiques anti-tumorales utilisant les cellules NK nécessite donc une compréhension approfondie des mécanismes de résistance développés au sein du microenvironnement tumoral. Les travaux menés au laboratoire ont révélé que certains mécanismes de résistance intrinsèque développés par les cellules tumorales dépendent de l’activation de l’autophagie en réponse à un stress hypoxique. Ces travaux ont démontré que l’activation de l’autophagie en condition de stress hypoxique, diminue la susceptibilité des cellules tumorales à la lyse par les cellules NK, qui peut être restaurée par l’inhibition de Beclin1. Ces mêmes travaux ont également démontré in vivo que l’inhibition de Beclin1 diminue la progression tumorale dans des modèles syngéniques murins de cancer de sein et de mélanome.Dans cette étude, nous avons montré dans un modèle murin de mélanome, que la régression des tumeurs déficientes en Beclin1 était corrélée à une augmentation significative d'infiltration des cellules NK. Nous avons établi que cette infiltration accrue est due à une augmentation d'expression et de sécrétion de la chémokine CCL5. De plus, dans les tumeurs déficientes en Beclin1, ayant une forte expression de CCL5, l’inhibition de CCL5 était suffisante pour diminuer l'infiltration des cellules NK et bloquer la régression tumorale.Ayant établi le rôle majeur de CCL5 dans l'infiltration des cellules NK dans les tumeurs de mélanome déficientes en Beclin1, nous avons étudié, dans la deuxième partie, le(s) mécanisme(s) moléculaire(s) impliqué(s) dans la régulation de CCL5. Nous avons démontré que l’inhibition génétique ou pharmacologique de l’autophagie induit la voie SAPK/JNK dans les cellules tumorales et active par conséquence le cofacteur de transcription c-Jun impliqué dans l'expression de CCL5. Plus précisément, nous avons établi que l'induction de SAPK/JNK est due à un défaut de l'activité phosphatase de la protéine phosphatase 2A (PP2A).Dans la dernière partie, nous avons étudié l'impact clinique de l’expression de CCL5 dans le cas du mélanome. L’analyse de différentes biopsies de mélanomes a montré une corrélation positive et significative de CCL5 avec l’expression du marqueur des cellules NK NKp46. Ce résultat a été validé sur une large collection de mélanomes, disponible dans la base de données TCGA (The Cancer Genome Atlas). La survie à long terme de patients atteints de mélanome ayant une expression élevée de CCL5 est significativement améliorée par rapport à ceux ayant une faible expression de cette chémokine.L'ensemble de nos résultats démontre pour la première fois que la diminution de la croissance tumorale suite l’inhibition de l'autophagie est étroitement liée à une amélioration de l'infiltration des cellules NK dans les tumeurs. Cette infiltration résulte d'une augmentation de l'expression la chémokine CCL5 par les cellules tumorales déficientes en Beclin1. Cette étude souligne l’intérêt de cibler l'autophagie afin d’établir un microenvironnement tumorale favorable à l'infiltration des cellules NK. Ainsi, l'inhibition sélective de l'autophagie dans les cellules tumorales pourrait améliorer les stratégies thérapeutiques anti-tumorales basées sur les cellules NK. / One of the major obstacles to define an efficient cancer immunotherapy protocol is the capacity of hypoxic tumor microenvironment to inhibit the host immune response. In line with this concept, we have shown that hypoxia impairs natural killer (NK) cell-mediated killing of cancer cells. This impairment was not related to a defect in NK cell function, but was strikingly dependent on the induction of the autophagic degradation process in hypoxic tumor cells. Genetic or pharmacological inhibition of autophagy restored NK-mediated killing of hypoxic tumor cells. . We have validated this concept in vivo by showing that targeting autophagy enhanced the NK-mediated regression of breast and melanoma tumors in mice. This regression was related to an increase in NK cells infiltrating autophagy defective tumor as demonstrated by immunohistochemistry staining of NK cells. The present project aims to investigate how autophagy inhibition increases tumor infiltration by NK cells leading to an improvement of NK-mediated anti-tumor immune response et to identify fectors which may be implicated in the infiltration of NK cells into the tumors.
328

Characterization of CD49A+ NK cells in SIV/SHIV-infected rhesus macaques

Arias, Christian Fernando 09 October 2019 (has links)
BACKGROUND: Natural killer (NK) cells are traditionally considered part of the innate immune system but have recently been shown to possess adaptive qualities similar to T cells in response to an infection with a pathogen. In addition to possessing adaptive features, NK cells have also been found to reside in different organs such as the liver, spleen, and lymph nodes and differ based on phenotypic markers and their responses to different cytokines. Utilizing these findings, several groups have isolated and identified CD49a as a marker for tissue-resident NK cells. In the liver, CD49a has also been shown to be a positive indicator for NK cell memory-like responses in murine models. Building off work that demonstrated antigen-specific responses in rhesus macaques, this project focuses on characterizing the phenotypic markers and functional profile of CD49a+ NK cells in non-human primates. To better understand the role of CD49a in memory-like NK cells outside of the liver, this project utilized spleen samples from rhesus macaques infected with SIV/SHIV. This work aims to help us better understand the dysfunction NK cells experience as a result of HIV-1 infection in humans and also to demonstrate the changes NK cells experience as the disease progresses. A thorough understanding of the adaptive capabilities of NK cells can pave the way for targeted therapies to increase NK cell antiviral activity in HIV and other infections. METHODS: To characterize the functional and phenotypic profiles of CD49a+ NK cells by multiparameter flow cytometry, thirteen samples of spleen from rhesus macaques were thawed and then stained with two different protocols. A phenotyping protocol involved staining with antibodies against surface markers as well as intracellular markers T-Bet and Eomes. For the functional characterization protocol, the same thirteen samples were stained intracellularly after being stimulated with a cocktail of PMA and ionomyocin. The antibodies used in this were for functional markers. Of the thirteen samples used, six were infected with SHIVSF162P3, two were infected with SIVmac239X, and the remaining five were uninfected. After staining, these samples were analyzed on an BD LSRII from BD Biosciences. The data obtained were then analyzed using FlowJo software to study NK cells, which were characterized as CD45+CD14-CD20-CD3-CD159+. RESULTS: The analysis compared NK cells with T cells, B cells, and NKB cells. Some increases were seen among CD49a+ NK cells in the frequency of CD336+ (NCR2/NKp44), CD337+ (NKp30), and CD366+ (Tim-3) after infection. Although there were some mild increases in CD107a and TNF- in infected samples compared to uninfected, a significant increase was observed in the frequency of IFN-ɣ among infected CD49a+ NK cells compared to uninfected. CONCLUSION: When comparing samples that were infected vs uninfected, it appears there were some mild decreases after infection in the ratio of NK cells to other lymphocytes. In addition, there did not appear to be a significant increase in the frequency of CD49a+ among these NK cells as a result of the infection. However, among the CD49a+ subpopulation, there were some observed non-significant decreases in CD56-CD16+ cells. Furthermore, there was found to be an almost significant increase in TNF- (p = 0.06) among CD49a+ cells after infection. These findings demonstrate an increase in cytotoxic activity in splenic NK cells associated with an adaptation to the virus. Although there does not appear to be significant changes in the ratio of NK cell populations in the spleen, the changes observed in phenotypic and functional markers associated with CD49a+ demonstrate an increase in the cytotoxic activity of NK cells as a result of infection with SIV/SHIV. However, it remains to be seen if CD49a is a direct indicator of this type of infection. Future work geared toward memory-like NK cells in non-human primate splenic tissue could look at the contrast in CD49a+ NK cells from different states of infection with HIV-1 and/or SIV (acute vs chronic) to better understand the integrin’s role in adaptation.
329

The role of metabolism in the anti-tumor cytotoxicity of natural killer cells

Lewis, Derrick Brian 10 October 2019 (has links)
Since their discovery, natural killer cells (NK) cells have been implicated as important players in cancer immunosurveillance. In recent years, researchers have taken advantage of this role by developing NK cell-based immunotherapies in the fight against cancer. While these treatments have been moderately successful against hematological malignancy, they are less effective against solid cancers. This lack of success partially results from the immunosuppressive effects of the tumor microenvironment (TME). While tumors use myriad processes to evade the immune system, the avid consumption of nutrients common to NK and cancer cell metabolism and the production of toxic waste products can have significant deleterious effects on NK cell anti-tumor function. However, it may be possible to avoid some of this tumor-induced inhibition of NK cell anti-tumor function by manipulating NK cell metabolism and/or environmental conditions. Recent studies have revealed that different activation regimens can affect the metabolic dependencies of different NK cell subsets. Furthermore, studies have identified potential targets in the TME that can make the environment less hostile for infiltrating NK cells. By considering the interrelationship of NK cell metabolism and function—especially in the TME—this thesis illuminates potential strategies to modulate immunometabolic suppression. Despite the promising work already done, many gaps in the knowledge of NK cell metabolism remain. Future work will need to investigate the specific molecular mechanisms linking metabolism and function, the role of tissue-resident NK cells in cancer immunosurveillance, and the influences of chronic disease and altered systemic metabolism on NK cell anti-tumor activity.
330

Problematika osobnosti pachatele v kriminologii. Pachatelé sériových vražd. / The Issue of an Offender's Personality in Criminology. Serial killers.

Adámková, Denisa January 2019 (has links)
The Issue of an Offender's Personality in Criminology Serial killers The cardinal topic of this diploma thesis is an analysis of an offender's personality and the major focus is given on serial killers. Although the serial killer's personality is the main topic of the thesis, a significant part deals with a criminological, forensic psychological and legal theory, involving the explanation of the relevant legal terms. This diploma thesis aims to provide the reader a comprehensive overview of serial killers. The main goal of the thesis is not only to offer probable profile of the serial killer, but to introduce Czech and foreign expert findings into the context with the Czech law and jurisprudence as well. Also, the thesis aims to help the reader to perceive differences among serial killers, mass killers and spree killers, as these multiple killers are often confused. I present some real cases for better illustration of the issue. From the huge amount of serial killers, I have chosen the most interesting or the most recent ones. In the first chapter I explain the term offender. I distinguish the legal and criminological point of view. The cardinal topic of the second chapter is the offender's personality. The first part of this chapter is focused psychologically, nevertheless in the introduction I...

Page generated in 0.0261 seconds