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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.
1

Evaluation of high-throughput methodology for multi-gene screening in patients with Non-Alcoholic Fatty Liver Disease (NAFLD)

Fisher, Leslie Reginald 12 1900 (has links)
Thesis (MScMedSc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Non-Alcoholic Fatty Liver Disease (NAFLD) is the most prevalent chronic liver disease in Western countries and is considered the hepatic manifestation of the Metabolic Syndrome (MetS). Its heterogeneous nature ranges from hepatic steatosis through steatohepatitis to advanced fibrosis and cirrhosis where the ingestion of significant amounts of alcohol has been excluded. The disease profile of NAFLD and its necro-inflammatory subset Nonalcoholic Steatohepatitis (NASH) were described in the parent study, which provided a clinically well-characterised patient cohort for the present investigation. South African patients with NASH had significantly higher mean serum cholesterol and triglyceride levels than those with fatty liver only. The objective of this study was to implement a high-throughput real-time polymerase chain reaction (PCR) method in our laboratory to enable the assessment of cardiovascular genetic risk factors in NAFLD patients. The specific aims were to determine the clinical utility and perform analytical validation of each mutation included in the multi-gene cardiovascular disease (CVD) screening assay. The Pathology Supported Genetic Testing (PSGT) concept developed at our department provides a practical approach to personalized medicine. The CVD multi-gene screen analyses key metabolic pathways relating to atherogenic dyslipidaemia, chronic inflammation, hypercoagulation and iron dysregulation implicated in insulin resistance, which is known to be a universal factor in the pathogenesis of NAFLD. Deleterious low-penetrance mutations in the APOE (APOE2 and E4 alleles), MTHFR (677C>T and 1298A>C), F2 (20210G>A), FV (1691G>A, Leiden) and HFE (C282Y and H63D) genes were included for analysis due to their important role as genetic contributors to these biological processes. A total of 178 patients diagnosed with NAFLD and 75 controls were studied using direct DNA sequencing and a RT-PCR system for mutation detection. In addition, two patients with high ferritin levels were included as case studies. A significant association was found between HFE mutations and elevated Alanine Transaminase (ALT) levels in the NAFLD population (p = 0.04). This discovery is interpreted as the identification of a subset of patients at greater risk of developing progressive liver damage who would benefit most from genetic testing to direct more aggressive therapy at an earlier stage. The necessity of an integrative, systems-based network approach was demonstrated to more accurately distinguish between Hereditary Haemochromatosis (HH) and Insulin Resistance-associated Hepatic Iron Overload (IR-HIO) syndrome in obese patients. The PSGT approach to personalized medicine facilitates diagnosis of CVD subtypes, prevention of cumulative risk and the formulation of gene-based intervention programs tailored to the needs of the patient. These findings support the clinical utility of the CVD multi-gene test to guide chronic disease risk management in patients with NAFLD. The HFE mutation detection component of this test is of particular relevance in directing an effective treatment strategy in patients with a medical history of CVD and/or high iron stores. / AFRIKAANSE OPSOMMING: Nie-Alkoholiese Vettige Lewer Siekte (NAFLD) is die mees algemene kroniese lewer siekte in Westerse lande en word bestempel as die hepatiese manifestasie van die Metaboliese Sindroom (MetS). Die heterogene natuur van NAFLD strek van hepatiese steatose deur steatohepatietis tot gevorderde fibrose en sirrose waar grootskaalse alkohol inname uitgesluit is. Die siekte-profiel van NAFLD en sy nekro-inflammatoriese subtipe Nie-Alkoholiese Steatohepatietis (NASH) is reeds beskryf in die ouer studie, wat ‗n klinies goed-gekarakteriseerde pasiënt groep vir die huidige ondersoek daar gestel het. Suid-Afrikaanse pasiënte met NASH het beduidend hoër gemiddelde serum cholesterol en trigliseried vlakke in vergelyking met slegs vettige lewer. Die doel van hierdie studie was om ‗n hoë deurvoer rieëltyd polimerase kettingreaksie (RT-PCR) metode in ons laboratorium te implimenteer om kardiovaskulêre genetiese risiko faktore in NAFLD pasiënte te ondersoek. Die spesifieke mikpunte was om die kliniese nut en analitiese geldigheid van elke mutasie wat ingesluit is in die multi-geen kardiovaskulêre siekte (KVS) siftings toets vas te stel. Die Patologie Ondersteunde Genetiese Toetsing (PSGT) konsep wat by ons departement ontwikkel is, verskaf ‗n praktiese benadering tot persoonlike medisyne. Die KVS multi-geen toets analiseer belangrike metaboliese weë verwant aan atherogene dyslipidemie, kroniese inflammasie, oormatige bloedstolling en yster disregulering wat betrokke is by insulien weerstand wat bekend is as ‗n universele factor in the patogenese van NAFLD. Nadelige lae-penetrasie mutasies in die APOE (APOE2 en E4 allele), MTHFR (677C>T en 1298A>C) F2 (20210G>A), FV (1691G>A, Leiden) en HFE (C282Y en H63D) gene was ingesluit vir analise as gevolg van hul belangrike rol as genetiese bydraers tot die bogenoemde biologiese prosesse. ‗n Totaal van 178 pasiënte gediagnoseer met NAFLD en 75 kontroles is bestudeer deur gebruik te maak van direkte DNA volgordebepaling en ‗n RT-PCR metode vir mutasie opsporing. Twee pasiënte met verhoogde ferritien vlakke is ook as gevalle studies ingesluit. ‗n Beduidende assosiasie is gevind tussen HFE mutasies en verhoogde Alanien Transaminase (ALT) vlakke in die NAFLD studiepopulasie (p = 0.04) wat aanduidend is van ‗n subgroup van pasiënte wat die meeste baat sal vind uit genetiese toetsing om meer aggressiewe behandeling te rig op' n vroeër stadium. Die noodsaaklikheid van 'n geïntegreerde, stelsels-gebaseerde netwerk benadering is gewys om meer akkuraat te onderskei tussen Oorerflike Hemochromatose (HH) en Insulien Weerstand-geassosieerde Hepatiese Yster Oorlading (IR-HIO) sindroom in vetsugtige pasiënte. Die PSGT benadering tot persoonlike medisyne formuleer geen-gebaseerde intervensie programme aangepas tot die behoeftes van die pasiënt ek maak diagnose van KVS-subtipes en voorkoming van kumulatiewe risiko moontlik. Hierdie bevindinge ondersteun die kliniese nut van die KVS multi-geen toets om riglyne vir die risikobestuur van kroniese siektes soos NAFLD daar te stel. Die HFE mutasie opsporings komponent van hierdie toets is van besondere belang om 'n effektiewe strategie vir die behandeling van pasiënte met 'n mediese geskiedenis van KVS en/of hoë yster vlakke daar te stel.
2

Discovery and evolutionary dynamics of RBPs and circular RNAs in mammalian transcriptomes

Badve, Abhijit 30 March 2015 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / RNA-binding proteins (RBPs) are vital post-transcriptional regulatory molecules in transcriptome of mammalian species. It necessitates studying their expression dynamics to extract how post-transcriptional networks work in various mammalian tissues. RNA binding proteins (RBPs) play important roles in controlling the post-transcriptional fate of RNA molecules, yet their evolutionary dynamics remains largely unknown. As expression profiles of genes encoding for RBPs can yield insights about their evolutionary trajectories on the post-transcriptional regulatory networks across species, we performed a comparative analyses of RBP expression profiles across 8 tissues (brain, cerebellum, heart, lung, liver, lung, skeletal muscle, testis) in 11 mammals (human, chimpanzee, gorilla, orangutan, macaque, rat, mouse, platypus, opossum, cow) and chicken & frog (evolutionary outgroups). Noticeably, orthologous gene expression profiles suggest a significantly higher expression level for RBPs than their non-RBP gene counterparts, which include other protein-coding and non-coding genes, across all the mammalian tissues studied here. This trend is significant irrespective of the tissue and species being compared, though RBP gene expression distribution patterns were found to be generally diverse in nature. Our analysis also shows that RBPs are expressed at a significantly lower level in human and mouse tissues compared to their expression levels in equivalent tissues in other mammals: chimpanzee, orangutan, rat, etc., which are all likely exposed to diverse natural habitats and ecological settings compared to more stable ecological environment humans and mice might have been exposed, thus reducing the need for complex and extensive post-transcriptional control. Further analysis of the similarity of orthologous RBP expression profiles between all pairs of tissue-mammal combinations clearly showed the grouping of RBP expression profiles across tissues in a given mammal, in contrast to the clustering of expression profiles for non-RBPs, which frequently grouped equivalent tissues across diverse mammalian species together, suggesting a significant evolution of RBPs expression after speciation events. Calculation of species specificity indices (SSIs) for RBPs across various tissues, to identify those that exhibited restricted expression to few mammals, revealed that about 30% of the RBPs are species-specific in at least one tissue studied here, with lung, liver, kidney & testis exhibiting a significantly higher proportion of species specifically expressed RBPs. We conducted a differential expression analysis of RBPs in human, mouse and chicken tissues to study the evolution of expression levels in recently evolved species (i.e., humans and mice) than evolutionarily-distant species (i.e., chickens). We identified more than 50% of the orthologous RBPs to be differentially expressed in at least one tissue, compared between human and mouse, but not so between human and an outgroup chicken, in which RBP expression levels are relatively conserved. Among the studied tissues (brain, liver and kidney) showed a higher fraction of differentially expressed RBPs, which may suggest hyper- regulatory activities by RBPs in these tissues with species evolution. Overall, this study forms a foundation for understanding the evolution of expression levels of RBPs in mammals, facilitating a snapshot of the wiring patterns of post-transcriptional regulatory networks in mammalian genomes. In our second study, we focused on elucidating novel features of post-transcriptional regulatory molecules called as circRNA from LongPolyA RNA-sequence data. The debate over presence of nonlinear exon splicing such as exon-shuffling or formation of circularized forms has finally come to an end as numerous repertoires have shown of their occurrence and presence through transcriptomic analyses. It is evident from previous studies that along with consensus-site splicing non-consensus site splicing is robustly occurring in the cell. Also, in spite of applying different high-throughput approaches (both computational and experimental) to determine their abundance, the signal is consistent and strongly conforming the plausible circularization mechanisms. Earlier studies hypothesized and hence focused on the ribo-minus non-polyA RNA-sequence data to identify circular RNA structures in cell and compared their abundance levels with their linear counterparts. Thus far, the studies show their conserved nature across tissues and species also that they are not translated and preferentially are without poly (A) tail, with one to five exons long. Much of this initial work has been performed using non-polyA sequencing thus probably underestimates the abundance of circular RNAs originating from long poly (A) RNA isoforms. Our hypothesis is if the circular RNA events are not the artifact of random events, but has a structured and defined mechanism for their formation, then there would not be biases on preferential selection / leaving of polyA tails, while forming the circularized isoforms. We have applied an existing computational pipeline from earlier studies by Memczack et. al., on ENCODE cell-lines long poly (A) RNA-sequence data. With the same pipeline, we achieve a significant number of circular RNA isoforms in the data, some of which are overlapping with known circular RNA isoforms from the literature. We identified an approach and worked upon to identify the precise structure of circular RNA, which is not plausible from the existing computational approaches. We aim to study their expression profiles in normal and cancer cell-lines, and see if there exists any pattern and functional significance based on their abundance levels in the cell.
3

Эволюция переводоведения в Китае : магистерская диссертация / The evolution of translation in China

Лю, С., Liu, S. January 2021 (has links)
Текущий уровень развития теории перевода на китайский язык не соответствует потребностям академических кругов. В настоящее время теория китайского перевода полностью не определена, и специфика условий ее развития имеет смысл. Цель данной статьи - изучить и проанализировать текущую ситуацию, систематизировать и обобщить накопленные данные по данной теме. Поскольку китайская переводческая индустрия находится на стадии становления, мы выдвинули наши собственные предложения и новые идеи по основному историческому направлению развития китайских теорий перевода на основе обширного анализа и на основе результатов существующих исследований. Теория китайского перевода нацелена на сохранение собственной идентичности и адаптацию успешного опыта Запада к его реальности. / The current level of development of the theory of translation into Chinese does not correspond to the needs of the academic community. At present, the theory of Chinese translation is not fully defined, and the specifics of the conditions for its development make sense. The purpose of this article is to study and analyze the current situation, systematize and summarize the accumulated data on this topic. As the Chinese translation industry is in its infancy, we have put forward our own proposals and new ideas for the main historical direction of the development of Chinese translation theories based on extensive analysis and based on the results of existing research. The theory of Chinese translation is aimed at preserving one's own identity and adapting the successful experience of the West to its reality.
4

Lexical cohesion register variation in transition : "The merchants of Venice" in afrikaans

Kruger, Alet 03 1900 (has links)
On the assumption that different registers of translated drama have different functions and that they therefore present information differently, the aim of the present study is to identify textual features that distinguish an Afrikaans stage translation from a page translation of Shakespeare's The Merchant of Venice. The first issue addressed concerns the nature and extent of lexical cohesion in these two registers. The second issue concerns my contention that the dialogue of a stage translation is more "involved". (Biber 1988) than that of a page translation. The research was conducted within the overall Descriptive Translation Studies (DTS) paradigm but the analytical frameworks by means of which these aims were accomplished were derived from text linguistics and register variation studies, making this an interdisciplinary study. Aspects of Hoey's ( 1991) bonding model, in particular, the classification of repetition links, were adapted so as to quantify lexical cohesion in the translations. Similarly, aspects of Biber's (1988) multi-dimensional approach to register variation were used to quantify linguistic features that signal involvement. The main finding of the study is that drama translation register (page or stage translation) does have a constraining effect on lexical cohesion and involved production. For Act IV of the play an overall higher density of lexical cohesion strategies was generated by the stage translation. In the case of the involved production features analysed, the overall finding was that the stage translation displayed more involvement than the page translation, to a statistically highly significant extent. The features analysed here cluster together sufficiently to reveal that in comparison with an Afrikaans page translation of a Shakespeare play, a recent stage translation displays a definite tendency towards a more oral, more involved and more situated style, reflecting no doubt a general modern trend towards creating more appropriate and accessible texts / Linguistics / D. Litt. et Phil. (Translation Studies)
5

Lexical cohesion register variation in transition : "The merchants of Venice" in afrikaans

Kruger, Alet 03 1900 (has links)
On the assumption that different registers of translated drama have different functions and that they therefore present information differently, the aim of the present study is to identify textual features that distinguish an Afrikaans stage translation from a page translation of Shakespeare's The Merchant of Venice. The first issue addressed concerns the nature and extent of lexical cohesion in these two registers. The second issue concerns my contention that the dialogue of a stage translation is more "involved". (Biber 1988) than that of a page translation. The research was conducted within the overall Descriptive Translation Studies (DTS) paradigm but the analytical frameworks by means of which these aims were accomplished were derived from text linguistics and register variation studies, making this an interdisciplinary study. Aspects of Hoey's ( 1991) bonding model, in particular, the classification of repetition links, were adapted so as to quantify lexical cohesion in the translations. Similarly, aspects of Biber's (1988) multi-dimensional approach to register variation were used to quantify linguistic features that signal involvement. The main finding of the study is that drama translation register (page or stage translation) does have a constraining effect on lexical cohesion and involved production. For Act IV of the play an overall higher density of lexical cohesion strategies was generated by the stage translation. In the case of the involved production features analysed, the overall finding was that the stage translation displayed more involvement than the page translation, to a statistically highly significant extent. The features analysed here cluster together sufficiently to reveal that in comparison with an Afrikaans page translation of a Shakespeare play, a recent stage translation displays a definite tendency towards a more oral, more involved and more situated style, reflecting no doubt a general modern trend towards creating more appropriate and accessible texts / Linguistics and Modern Languages / D. Litt. et Phil. (Translation Studies)
6

The role of the CTD phosphatase Rrt1 and post-translational modifications in regulation of RNA polymerase II

Cox, Mary L. 07 July 2014 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / RNA polymerase II (RNAPII) is regulated by multiple modifications to the C-terminal domain (CTD) of the largest subunit, Rpb1. This study has focused on the relationship between hyperphosphorylation of the CTD and RNAPII turnover and proteolytic degradation as well as post-translational modifications of the globular core of RNAPII. Following tandem affinity purification, western blot analysis showed that MG132 treated RTR1 ERG6 deletion yeast cells have accumulation of total RNAPII and in particular, the hyperphosphorylated form of the protein complex. In addition, proteomic studies using MuDPIT have revealed increased interaction between proteins of the ubiquitin-proteasome degradation system in the mutant MG132 treated yeast cells as well as potential ubiquitin and phosphorylation sites in RNAPII subunits, Rpb6 and Rpb1, respectively. A novel Rpb1 phosphorylation site, T1471-P, is located in the linker region between the CTD and globular domain of Rpb1 and will be the focus of future studies to determine biological significance of this post-translational modification.

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