Thesis (MPH) -- University of Limpopo, 2012. / No Summary

Thesis (MPH (Faculty of Medicine))--University of Pretoria, 2006. / Abstract in English. Includes bibliographical references .

Thesis (Ph.D.)--Drexel University, 2009. / Includes abstract and vita. Includes bibliographical references (leaves 79).

Thesis (MNutr)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Thesis (M.Public Health) -- University of the Western Cape, 2008. / Includes bibliographic references (leaves 47-67).

Thesis (M.PH (Faculty of Medicine))--University of Pretoria, 2005. / Abstract in English. Includes bibliographical references (leaves 39-40). Also available online.

Not available / text

Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: While antiretroviral therapy decreases HIV/AIDS morbidity and mortality, long-term treatment results in insulin resistance and cardiovascular diseases. A possible cause of such adverse effects may be an increase in oxidative stress resulting from protease inhibitor (PI)-induced mitochondrial dysfunction. We therefore hypothesized that PI treatment, specifically Lopinavir/Ritonavir, results in increases in myocardial reactive oxygen species (ROS), leading to downstream outcomes, i.e. elevated apoptosis. Moreover, we proposed that increased ROS levels in this instance might occur as a result of PI-mediated induction of the non-oxidative glucose pathways (NOGPs). In light of this, we also investigated the effect of PI treatment on the NOGPs by employing both in vitro and in vivo samples. For the in vitro work we employed a rat cardiomyoblast cell line, while tissues (heart, liver) were collected from two separate experimental models, i.e. a) Group A exposed to PIs via mini-osmotic pump for a period of eight weeks, and b) Group B administered PIs via a jelly-based method for 16 weeks. We found that PIs increased mitochondrial ROS levels in vitro but that this was not accompanied by a parallel rise in programmed cell death. Moreover, we found no induction of the NOGPs in response to PI exposure (for both in vitro and in vivo models here employed). However, we found that the AGE pathway was significantly down-regulated in the liver of Group A. Investigation into a proposed mechanism for this observation proved inconclusive and further studies are thus required to clarify the significance in terms of metabolic dysfunction found in the Group A model. Our study thus shows that PIs can increase ROS levels (in vitro) but that compensatory antioxidant mechanisms may prevent this in vivo. Subsequently, downstream effects were limited i.e. we did not observe NOGP induction and programmed cell death. An intriguing finding emerged, however, i.e. that PIs can elicit an impact on the AGE pathway. We propose future studies with modifications to the current rat and cell models in order to evaluate the downstream effects of PIs on the NOGPs and programmed cell death. / AFRIKAANSE OPSOMMING: Terwyl antiretrovirale terapie MIV/VIGS morbiditeit en mortaliteit verlaag, veroorsaak langtermyn behandeling insulienweerstandigheid en kardiovaskulêre siekte. 'n Moonltike oorsaak van sulke newe-effekte kan 'n toename in oksidatiewe stres veroorsaak deur die protease inhibeerder (PI)-geïnduseerde mitochondriale wanfunskionering. Ons hipotetiseer dat PI behandeling, spesifiek Lopinavir/Ritonavir, versoorsaak 'n toename in miokardiale reaktiewe suurstofspesies (ROS), wat aanleiding gee tot afstroom uitkomste, i.e. verhoogde apoptose. Verder, stel ons voor dat verhoogde ROS vlakke in hierdie geval onstaan as gevolg van PI-gemedieerde induksie van die nie-oksidatiewe glukose weë (NOGWe). In die lig hiervan het ons ook die effek van PI behandeling op die NOGWe ondersoek deur beide in vitro en in vivo monsters te gebruik. Vir die in vitro werk het ons van 'n rot kardio-mioblastsellyn gebruik gemaak, terwyl weefsels (hart, lewer) versamel is van twee afsonderlike eksperimentele modelle, i.e. a) Groep A blootgestel aan PIs via mini-osmotiese pomp vir 'n periode van agt weke, en b) Groep B PIs is toegedien via 'n jellie gebaseerde metode vir 16 weke. Ons het bevind dat die die PIs mitochondriale ROS vlakke in vitro verhoog maar dat dit nie vergesel is met 'n paralelle toename in apoptose. Verder is geen induksie van die NOGWe in reaksie op PI blootstelling waargeneem (vir beide in vitro en in vivo modelle). Hoewel ons het bevind dat die AGE weg in die lewer van Groep A beduidend afgereguleer is. Ondersoek na 'n moontlike megansime vir hierdie waarneming was onoortuigend en verdere ondersoek is nodig om die betekenis in terme van die metaboliese wanfunskionering in die Groep A model vas te stel. Ons studie toon dus aan dat PIs, ROS vlakke (in vitro) verhoog, maar dat kompensatoriese anti-oksidant meganismes in die hierdie in vivo model verhoed word. Gevolglik is die afstroom effekte beperk i.e. ons het geen NOGWe induksie en aptoptose waargeneem nie. 'n Interesante bevinding het wel uitgestaan, i.e. PIs kan 'n impak hê op die AGE weg. Ons stel dus voor dat toekomstige studies met modifikasies, tot die huidige rot- en sel-modelle gemaak word om die afstroomeffekte van PIs en apoptose te evalueer.

Successful antiretroviral (ARV) treatment is associated with suppression of HIV viral load and the reduction of clinical disease progression. Despite marked improvements in ARV medication, side effects from long-term treatment, such as loss of muscle mass do occur. The mechanism by which ARVs affect muscle mass is unclear, however, published in vitro data suggests a negative effect on myoblast fusion during differentiation. The objective of this study was therefore to determine the effect of ARVs on processes required for successful myogenesis; these included proliferation, migration during wound repair, and differentiation. C2C12 mouse skeletal myoblasts and human primary culture skeletal (HSk) myoblasts were incubated with Zidovudine (nucleoside reverse transcriptase inhibitor-NRTI), Tenofovir (nucleotide reverse transcriptase inhibitor-NtRTI) or Ritonavir (protease inhibitor-PI) at a concentration range of 0.01 μM to 10 μM. Proliferation was determined using crystal violet and migration was analyzed using a 2D wound healing assay. The commitment of myoblasts into the myogenic lineage was assessed via the expression of the transcription factor Pax7. Differentiation was measured by assessing the fusion index of multinucleated myotubes. C2C12 myoblast proliferation was observed to increase significantly in response to Tenofovir (1 μM and 10 μM). In HSk cells however, proliferation was observed to decrease significantly in response to Tenofovir (1 μM). Zidovudine had no consistent effect on C2C12 proliferation at any dose tested, but caused a decrease in HSk myoblast proliferation (0.01 μM and 0.1 μM); however this was statistically non-significant. A small dose-dependent increase in C2C12 and HSk cell number, although not significant, was seen in response to Ritonavir. Wound closure results revealed both dose-dependent and time-dependent effects of Tenofovir and Zidovudine on human myoblast migration, with significant decreases in the rate of wound closure (4-7 hours) noted at 0.1 μM and 0.01 μM doses respectively. Zidovudine had no significant effect on migration while Ritonavir (0.01 μM) was observed to significantly increase percentage wound closure of human myoblasts, suggesting an increased ability to migrate during wound repair. Differentiation results indicated a decrease in myoblast fusion in response to all three ARVs. However only Ritonavir was shown to negatively affect myosin heavy chain expression. Further research into the exact mechanism of decreased fusion is required. To our knowledge, this study is the first to suggest that selected ARVs may significantly influence myoblast regeneration capabilities by modulating myoblast proliferation, migration, differentiation and fusion, and thereby decrease their myogenic capability. Extended human myoblast studies on differentiation could confirm this hypothesis. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2013.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, in fulfillment of the requirements for the degree of Master of Science Johannesburg, August 2012 / It is known that infectious agents elicit different responses in different individuals which strengthens the view that susceptibility and resistance to infectious diseases has a genetic component. These differences in susceptibility to disease can be observed in populations. APOBEC3G is a member of the cytidine deaminase gene family located on chromosome 22. It is crucial in non-permissive cells as it functions as part of the innate immunity system and is an inhibitor of the HIV-1 accessory protein vif. The goal of the study was to develop genotyping assays and estimate allele frequencies. Thus, genetic variation within APOBEC3G was identified and characterized in black South Africans. Indirect genotyping assays were designed to amplify regions within the upstream non-coding region, and in exon 4 of the coding region of the gene. Selected polymorphisms were then genotyped using allele-specific PCR, RFLP-PCR and Pyrosequencing™ assays. Reanalysis of sequence data from 2003 showed numerous SNPs were well represented. Comparison of sequence data at various SNPs showed that allele frequencies were similar to frequencies in other African populations. The only sequenced SNP that deviated from the frequencies in Ensembl was -590. Thus the sequencing was a useful tool for detection of variation. ASA proved to be the least reliable genotyping technique as the minor allele frequency of -571 (0.59) deviated from the published frequency of 0.894 in Africans. RFLP analysis proved more reliable for genotyping -571 and H186R. The minor allele frequency was estimated to be 0.84 and 0.32 for -571 and H186R respectively. The frequency of H186R is similar to published data from An et al (2004) and Reddy et al (2010). If SNPs are in LD they occur together on the same haplotype more often than by chance. Usually SNPs that are in LD are in close proximity. However our data suggests -571 and H186R SNPs which are 5kb apart are not in LD. A LD map of chromosome 22 shows highly variable pattern of LD (Dawson et al, 2002). Widespread regions of nearly complete LD up to 804 kb in length are intermingled with regions of little or uundetectable LD. Haplotype analysis showed the most frequent haplotype was GA. This was the most frequent haplotype when the sample types were subdivided according to spoken language. in comparison to studies from An et al, (2004) D’ of the two SNPs was estimated at 0.967. The linkage disequilibrium (LD) revealed a non-independence of allele segregation because the loci analyzed were strongly linked in the Apobec 3 G gene. The data are consistent with greater genetic diversity of African populations and can form the basis for further evaluation of the role of variation in this gene in response to HIV.