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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.
271

Environmental risk factors for multiple sclerosis / Miljöfaktorers betydelse för multipel skleros

Salzer, Jonatan January 2013 (has links)
Background Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. It usually strikes during young adulthood, and 2.5 million individuals are estimated to have the disease worldwide. The causes of MS are not known, but several factors have been shown to be associated with the risk of the disease, including certain genes, vitamin D, smoking and Epstein- Barr virus infection. Little is known about how/if these factors interact. Methods Study I: The risk of MS by month of birth was investigated using MS cases from the Swedish MS registry and using general population controls. Studies II–V: We identified MS cases who had donated blood prior to disease onset, and MS cases whose mothers had donated blood during pregnancy, by cross-linking a database of MS cases, and a database of mothers of MS cases, to two local biobank cohorts. One of them consisted of blood samples collected during early pregnancy, and one with samples collected during health controls. Levels of 25(OH)D (25-hydroxyvitamin D), RBP (retinol binding protein, a surrogate marker for vitamin A), CRP (C- reactive protein), cotinine (a nicotine metabolite) and anti Epstein-Barr virus nuclear antigen-1 (EBNA-1) antibodies were measured in cases and matched controls. The risk of MS by categories of these exposures was estimated in bi- and multivariable matched logistic regression models. Results Subjects born in spring had a higher risk of MS, but no influence of early gestational levels of the measured risk factors on the risk of MS in the offspring was observed. In prospective samples from MS cases and controls, 25(OH)D levels ≥75 nmol/l, intermediate RBP levels, and elevated CRP levels in young were associated with a decreased risk of MS. Elevated cotinine levels (suggestive of smoking) and high antibody reactivity against EBNA-1 were associated with an increased risk of MS. All factors but RBP were more clearly associated with MS in young subjects. Conclusion All factors analyzed in prospectively collected samples were associated with the risk of MS, and taken together, the data indicate that the key etiopathological events that lead to MS occur before the age of 20–30. Study II provides support for trials exploring the primary preventive potential of oral vitamin D supplementation.
272

Etude des fonctions des protéines virales de la famille EBNA3 dans l'immortalisation des lymphocytes B par le virus d'Epstein-Barr : rôle fonctionnel de l'interaction entre EBNA-3A et la protéine cellulaire Miz-1

Bazot, Quentin 30 November 2012 (has links) (PDF)
Le virus d'Epstein-Barr (EBV) est un gamma-Herpesvirus associé à de nombreux cancers chez l'homme. In vitro, l'infection de lymphocytes B primaires par EBV conduit à leur immortalisation (genèse de lignées lymphoblastoides (LCL)). Dans ces cellules, seules 9 protéines virales (protéines dites de latence) sont exprimées et coopèrent pour stimuler la prolifération des cellules. Afin de comprendre les mécanismes moléculaires par lesquels les 3 protéines de latence de la famille EBNA3 (-3A, -3B et -3C) participent à l'induction et au maintien de la prolifération cellulaire induite par EBV, nous avons réalisé un crible deux-hybrides dans la levure en utilisant EBNA-3A, -3B ou -3C comme appâts. Ce crible nous a permis d'identifier de nombreux nouveaux partenaires particulièrement pertinents au vu de ce que l'on connaît des rôles respectifs des protéines EBNA3. Parmi les nouveaux partenaires de la protéine EBNA-3A se trouve le facteur de transcription Miz-1 qui est connu pour jouer un rôle clef dans l'arrêt du cycle cellulaire en transactivant l'expression de gènes tels CDKN1A, CDKN1C et CDKN2B. Nous avons validé cette interaction par GST-pull down ainsi que par co-immunoprécipitation en cellules humaines. Nous avons ensuite étudié l'effet de la protéine virale EBNA-3A sur l'activation de la transcription induite par Miz-1. Pour cela, nous avons comparé le niveau des transcrits de certains gènes cibles de Miz-1 dans des LCL exprimant ou non EBNA-3A et avons trouvé que certains gènes codant des inhibiteurs du cycle cellulaire sont différemment exprimés en présence d'EBNA-3A. Enfin, nous avons pu montrer que la protéine virale EBNA-3A est capable de réprimer l'activation de la transcription de Miz-1 en inhibant le recrutement de l'une de ses protéines co-activatrices, la protéine NPM. Ces résultats permettent de mieux comprendre les mécanismes par lesquels les protéines EBNA3 et plus largement EBV, dérégulent le cycle cellulaire.
273

Modulation of cellular and viral functions in Epstein-Barr virus infected cells /

Imreh, Marta P., January 2002 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.
274

Epstein-Barr virus latency in transplant patients and health carriers /

Zou, JieZhi. January 2005 (has links)
Lic.-avh. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 3 uppsatser.
275

Stem form, height and volume models for teak in Tanzania

Van Zyl, Louis 03 1900 (has links)
Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2005. / The aim of this study was to develop a set of models that will allow the determination of volume for Tectona grandis trees and stands grown in plantation form in Tanzania. As a secondary objective, models describing tree and dominant stand height were developed. Total volume and volume ratio models were fitted that respectively predict total tree volume and merchantable volume. In order to allow the calculation of volume for different product classes and dimensions, taper models were fitted. All the data were collected by non-destructive sampling methods using a Barr and Stroud optical dendrometer. This proved to be an accurate and inexpensive method of collecting data for developing volume and taper models. Sampling stratification was based on age and site quality and as wide a range as possible was covered to ensure adequate representation of all growing sites and ages present in Tanzanian teak plantations. A total of 2617 individual observations were made from 222 trees at three teak plantations. Several models were selected from the literature to describe teak volume and shape. Results indicated that the Schumacher and Hall (1933) volume equation best describes total volume over and underbark to a fixed upper limit of 7.5 cm. Merchantable volume to upper stem diameter and height limits were best described by respectively the Burkhart (1977) volume ratio model and the Cao and Burkhart (1980) modification thereof. Many of the fitted taper models were unable to adequately describe stem shape over the whole stem, mainly due to the large range in tree sizes and ages used in model fitting. The variable form taper model by Perez, Burkhart and Stiff (1990) provided the best results according to various criteria and is recommended for predicting teak underbark diameters to various heights and, if only a single model is required, the merchantable volume. Top height growth of teak stands was adequately described by the generalized Schumacher (1939) model with the value of the exponent k estimated from the sample data. From this a series of anamorphic site index curves were developed. Suitable height-dbh curves were obtained by a simple linear model and predictions improved by including stand age and site index as predictor variables.
276

Carcinoma de células escamosas oral: relevância do Papiloma vírus humano (HPV) e do vírus Epstein-Barr (EBV) na expressão de proteinas p16INK4a, E-caderina, COX-2, MLH1, p53 e MYC. / Oral squamous cell carcinoma: Relevance of Human Papillomavirus (HPV) and Epstein-Barr virus (EBV) on the expression of the proteins p16INK4a, E-cadherin, COX-2, MLH1, p53 e MYC.

Lima, Marcos Antonio Pereira de January 2013 (has links)
LIMA, Marcos Antonio Pereira de. Carcinoma de células escamosas oral: relevância do Papiloma vírus humano (HPV) e do vírus Epstein-Barr (EBV) na expressão de proteinas p16INK4a, E-caderina, COX-2, MLH1, p53 e MYC. 2013. 180 f. : Tese (doudorado) - Universidade Federal do Ceará, Programa de Pós-Graduação em Biotecnologia, Rede Nordestes de Biotecnologia -Renorbio, Fortaleza-CE, 2013. / Submitted by demia Maia (demiamlm@gmail.com) on 2016-05-27T13:30:28Z No. of bitstreams: 1 2013_tese_maplima.pdf: 16584856 bytes, checksum: 9b25880d41a42f87ebcd6222528b072e (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-05-27T13:30:59Z (GMT) No. of bitstreams: 1 2013_tese_maplima.pdf: 16584856 bytes, checksum: 9b25880d41a42f87ebcd6222528b072e (MD5) / Made available in DSpace on 2016-05-27T13:30:59Z (GMT). No. of bitstreams: 1 2013_tese_maplima.pdf: 16584856 bytes, checksum: 9b25880d41a42f87ebcd6222528b072e (MD5) Previous issue date: 2013 / The oral cancer represents a serious world public health problem. The oral squamous cell carcinomas (OSCC) account for up to 94% of the tumors of this anatomic site. The molecular mechanisms involved in the genesis and progression are still not well elucidated. Some evidences have suggested the involvement of viruses in this process. Also, these tumors still lack of reliable markers to determine the aggressiveness profile. In this context, the aim of the present study was to evaluate the expression of the proteins p53, E-cadherin, COX-2, p16, MLH1 and MYC in a serie of OSCC, including the cytoplasmic staining eventually observed for the latter three proteins, confronting the results between them and with demographic and clinico-pathological features. Besides evaluating the prevalence of Human Papillomavirus (HPV) and Epstein-Barr virus (EBV) in the sample and compare them with the expression of the referred proteins. Materials and Methods – One hundred formalin-fixed paraffin-embedded OSCC specimens were submitted to immunohistochemistry for detection of the referred proteins, and to in situ hybridization for HPV and EBV detection. Results – OSCC was associated with a concomitant lack of expression of p16 and MLH1 (p=0.029) and coexpression of p53 and COX-2 (p=0.045). Additionally, COX-2 and nuclear MYC were found to be related to exclusively cytoplasmic staining of MLH1 (p=0.060 and p=0.018, respectively). The combination analyses of the markers revealed five main groups of altered protein expression, which were mostly of the more aggressive tumors, mainly the MLH1(-)/COX-2(+)/p16(-) group. The cases with cytoplasmic staining for p16, MLH1 and/or MYC were more frequent in advanced tumors (p=0.009) and in those with lymph node metastasis (p=0.001). Thirty-one cases showed staining for HPV in tumor tissue. The EBV was not detected in any case investigated, neither in the tumor tissue nor in the non-neoplastic epithelium. The HPV(+) group demonstrated high positivity for nuclear p16 (p=0,029) and cytoplasmic MYC (p=0,039), and an increase of the lack of MLH1 nuclear expression (p=0,031). There was also a trend related to the increase of the COX-2 positivity in the HPV(+) group (p=0,084). Conclusions – The significance between p16 and MLH1 suggests that the lack of this member of mismatch repair system also favors the occurrence of mutations in the p16 gene, culminating in inactivation of this tumor suppressor. The associations of COX-2 and MYC with cytoplasmic MLH1 suggest a blocking mechanism for the entry of MLH1 into the nucleus. The combined analyses of the proteins investigated, as well as the cytoplasmic staining of p16, MLH1 and MYC, may be useful in the evaluation of the aggressive profile and probably prognosis of OSCC. Regarding the viruses, our findings suggest that the HPV is involved in an important portion of OSCC cases and that may promote the expression of the nuclear p16, cytoplasmic MYC and COX-2, and suppress the nuclear expression of MLH1. About EBV, it was not detected the EBV-encoded small RNAs (EBERs) in the sample. / O câncer oral representa um sério problema de saúde pública mundial. Entre os tumores deste sítio anatômico, os carcinomas de células escamosas orais (CCEO) respondem por até 94% do total. Os mecanismos moleculares envolvidos na gênese e desenvolvimento tumoral ainda não estão completamente elucidados. Algumas evidências têm sugerido a participação viral neste processo. Além disso, estes tumores ainda carecem de marcadores confiáveis para determinar o perfil de agressividade. Neste contexto, o presente estudo teve como objetivo avaliar a expressão das proteínas p53, E-caderina, COX-2, p16, MLH1 e MYC numa série de CCEO, considerando também a marcação citoplasmática eventualmente observada para as últimas três proteínas, confrontando os resultados entre elas e com as características demográficas e clínico-patológicas. Além de avaliar a prevalência do Papilomavírus Humano (HPV) e do Vírus Epstein-Barr (EBV) na amostra e compará-las com a expressão das referidas proteínas. Materiais e Métodos – Cem espécimes de CCEO, fixados em formalina e incluídos em blocos de parafina, foram submetidos à imunohistoquímica para a detecção das referidas proteínas e à hibridação in situ para detecaçõ de HPV e EBV. Resultados – Foi observada associação referente à perda de expressão concomitante de p16 e MLH1 (p=0,029) e na coexpressão de p53 e COX-2 (p=0,045). Ademais, foi verificado que a COX-2 e o MYC nuclear estavam relacionados com a marcação citoplasmática de MLH1 (p=0,060 e p=0,018; respectivamente). A análise combinada dos marcadores revelou cinco grupos principais de expressão alterada que eram constituídos, em sua maioria, de tumores mais agressivos, principalmente o grupo MLH1(-)/COX-2(+)/p16(-). Os casos com marcação citoplasmática para p16, MLH1 e/ou MYC foram mais frequentes em tumores avançados (p=0,009) e naqueles com metástases em linfonodos (p=0,001). Trinta e um casos demonstraram marcação para HPV em tecido tumoral. O EBV não foi detectado em nenhum dos casos investigados, nem no tecido tumoral nem no epitélio não neoplásico. O grupo HPV(+) exibiu elevada positividade para o p16 nuclear (p=0,029) e MYC cytoplasmático (p=0,039), também uma maior perda de expressão nuclear de MLH1 (p=0,031). Houve ainda uma tendência referente ao aumento da positividade de COX-2 no grupo infectado (p=0,084). Conclusões – As significâncias verificadas entre p16 e MLH1 sugerem que a ausência do membro do sistema de reparo de encaixe (MMR) também favoreça a ocorrência de mutações no gene p16, culminando na inativação deste supressor tumoral. As associações de COX-2 e MYC com o MLH1 de expressão citoplasmática suscitam um mecanismo de bloqueio de entrada de MLH1 no núcleo. A análise combinada das proteínas, bem como, a marcação citoplasmática de p16, MLH1 e MYC, podem representar indicadores úteis na avaliação do perfil de agressividade e, provavelmente, de prognóstico em CCEO. Acerca dos vírus, nossos achados sugerem que o HPV esteja envolvido em uma importante parcela de casos de CCEO e que possa promover a expressão de p16 nuclear, MYC citoplasmático e COX-2, e suprimir a expressão nuclear de MLH1. Quanto ao EBV, não foram detectados EBERs (EBV-encoded small RNAs) na amostra.
277

Multiple sclerosis in Västerbotten county, northern Sweden

Sundström, Peter January 2003 (has links)
One out of several distinguishing features of multiple sclerosis (MS) is the epidemiological variation of geographic distribution. Population-based studies on the prevalence and incidence of MS in Sweden have previously been performed only in Göteborg. Another feature of MS is the clinical variation between individuals. To a large extent data on the clinical characteristics of MS come from studies on cases frequenting MS clinics and therefore, may be biased. Also rare are population-based studies of the consequences of MS-related incapacity on socio­economic factors. As for MS aetiology, both environment and genes are involved. Human herpesviruses are often the main suspected environmental aetiological agents. Our aim was to estimate the prevalence of MS in Västerbotten County for 1 January 1990, the incidence during a 10-year period 1988-97, and the prevalence 31 December 1997; and also to present detailed clinical data including onset symptoms and the disability distribution for the latter two MS populations. Furthermore, we wanted to estimate the prevalence of sick leave, professional assistance, and housing; and also, to study the risk factors for sick leave. In order to investigate the association between MS and human herpesviruses, samples were identified in two regional population-based serumbank registers. This linkage identified samples collected from before MS-onset in 73 MS cases and after MS onset in 161 cases The prevalence and incidence populations were identified through multiple sources. Diagnostic ascertainment, the reliability of clinical data, and additional information were assured from a questionnaire with follow-up interview and neurological examination. The onset adjusted crude prevalence of MS was 125/100,000 (95% CI: 112-140) in January 1990, and 154/100,000 (95% Cl: 139-170) in December 1997. The increase was mainly attributable to a higher incidence than mortality. The crude incidence rate 1988-97 was 5.2/100,000 (95% CI: 4.4-6.2). The disability distribution in the 1997 prevalence population in Västerbotten was compared to the disability distribution in a Canadian MS population, which has been used for publications on the natural history of MS. One difference from the Canadian studies appears to be the better recognition of cases with more benign disease. Nevertheless almost half of prevalent MS cases aged 18-64 years were fully sick-listed, and one-fourth of all prevalent cases received professional assistance. High disability level was the strongest predictor for sick leave. All MS cases showed signs of past Epstein-Barr virus (EBV) infection. High activity to EBV (EBNA-1 but not VCA) and human herpesvirus 6 (HHV-6) significantly (borderline significance for HHV-6) increased the risk to develop MS. These estimates show that Västerbotten County is a high risk area for MS. Both incidence and prevalence were significantly higher when compared to estimates from Göteborg. The comparison with the Canadian MS population shows that MS might be a slightly more benign disease than previously recognized. Still, the consequences of MS regarding socio-economic aspects are considerable. We suggest that EBV is a prerequisite for the development of MS. Individuals that will develop MS exhibit an altered immune response against the EBV virus characterised by high activities to EBNA-1 in the absence of high VCA activities, this being most pronounced in the five-year period preceding MS onset. A pathogenetic role is suggested for EBV and remains possible also for HHV-6. / digitalisering@umu
278

Genomic and Transcriptomic Investigation of Endemic Burkitt Lymphoma and Epstein Barr Virus

Kaymaz, Yasin 31 July 2017 (has links)
Endemic Burkitt lymphoma (eBL) is the most common pediatric cancer in malaria-endemic equatorial Africa and nearly always contains Epstein-Barr virus (EBV), unlike sporadic Burkitt Lymphoma (sBL) that occurs with a lower incidence in developed countries. Despite this increased burden the study of eBL has lagged. Additionally, while EBV was isolated from an African Burkitt lymphoma tumor 50 years ago, however, the impact of viral variation in oncogenesis is just beginning to be fully explored. In my thesis research, I focused on investigating molecular genetics of the endemic form of this lymphoma with a particular emphasis on the role of the virus and its variation in pathogenesis using novel sequencing and bioinformatic strategies. First, we sought to understand pathogenesis by investigating transcriptomes using RNA sequencing (RNAseq) from 30 primary eBL tumors and compared to sBL tumors. BL tumor samples were prospectively obtained from 2009 until 2012 in Kenya. Within eBL tumors, minimal expression differences were found based on anatomical presentation site, in-hospital survival rates, and EBV genome type; suggesting that eBL tumors are homogeneous without marked subtypes. The outstanding difference detected using surrogate variable analysis was the significantly decreased expression of key genes in the immunoproteasome complex in eBL tumors carrying type 2 EBV compared to type 1 EBV. Secondly, in comparison to previously published pediatric sBL specimens, the majority of the expression and pathway differences were related to the PTEN/PI3K/mTOR signaling pathway and was correlated most strongly with EBV status rather than the geographic designation. Moreover, the common mutations were observed significantly less frequently in eBL tumors harboring EBV type 1, with mutation frequencies similar between tumors with EBV type 2 and without EBV. In addition to the previously reported genes, we identified a set of new genes mutated in BL. Overall, these suggested that EBV, particularly EBV type 1, supports BL oncogenesis alleviating the need for particular driver mutations in the human genome. Second, we sought to comprehensively define sequence variations of EBV across the viral genome in eBL tumor cells and normal infections, and correlate variations with clinical phenotypes and disease risk. We investigated the whole genome sequence of EBV from primary tumors (N=41) and plasma from eBL patients (N=21) as well as EBV in the blood of healthy children (N=29) within the same malaria endemic region. We conducted a genome wide association analysis study with viral genomes of healthy kids and BL kids. Furthermore, we found that the frequencies of EBV types among healthy kids were at equal levels while they were skewed in favor of type 1 (70%) among eBL kids. To pinpoint the fundamental divergence between viral genome subtypes, type 1 and type 2, we constructed phylogenetic trees comparing to all public EBV genomes. The pattern of variation defined the substructures correlated with the subtypes. This investigation not only deciphers the puzzling pathogenic differences between subtypes but also helps to understand how these two EBV types persist in the population at the same time. Overall, this research provides insight into the molecular underpinning of eBL and the role of EBV. It further provides the groundwork and means to unravel the complexity of EBV population structure and provide insight into the viral variation that may influence oncogenesis and outcomes in eBL and other EBV-associated diseases. In addition, genomic and mutational analyses of Burkitt lymphoma tumors identify key differences based on viral content and clinical outcomes suggesting new avenues for the development of prognostic molecular biomarkers and therapeutic interventions.
279

Student experiences of a developmental shift in reflective judgment in one Intermediate Accounting I classroom: A qualitative study

Chase, Linda 13 December 2011 (has links)
No description available.
280

Brevard Childs : the logic of scripture's textual authority

Driver, Daniel R. January 2009 (has links)
Brevard Childs argues for the inner logic of scripture’s textual authority as an historical reality that gives rise to the material condition by which the church apprehends and experiences God in Christ. The church’s use of (or by) scripture thus has a larger interiority: the shaped canon of scripture, Old and New Testaments, is a rule of faith which accrues authority in the church, through the vehicle of the sensus literalis. Childs’ work has been misplaced, however. Part one locates it internationally, attending to the way it has been read in English and German and finding that it has enjoyed a more patient reception in Europe than in Britain or North America. To illustrate, Childs’ definition of biblical theology is contrasted with that of James Barr. Their differences over gesamtbiblische theology involve opposite turns toward and away from Barthian dogma in biblical inquiry. Part two examines Childs on biblical reference, introducing why intertextuality is not midrashic but deictic—pointing to the res. This coincides with an understanding of the formation of biblical literature. Childs’ argument for canonical shaping is juxtaposed with Hermann Gunkel on tradition history, showing “final form” to be a deliberate inversion of form critical principles. Childs’ interest in the Bible as religious literature is then set alongside his studious confrontation of Judaism, with implications for inter-religious dialogue. Barr and Childs are compared again in part three, which frames their respective senses of indirect and direct biblical reference in terms of allegory. Both see allegory at work in the modern world under certain rules (either biblical criticism or the regula fidei). Their rules affect their articulations of trinitarian dogma. Finally, Psalm102 highlights divergences between modern and pre-modern interpreters. If scripture comprehends the present immediately, some postures of the church toward the synagogue may be excluded.

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