Thesis (Ph. D.)--Curtin University of Technology, 2004. / Includes bibliographical references (p. 278-298).

No description available.

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Chronic inflammation and immune activation are hallmarks of HIV infection, resulting in chronic oxidative stress with over-utilization of antioxidant defences, which may contribute to the loss of immune cells and faster disease progression. Low levels of antioxidants in HIV- infected individuals have been associated with frequent opportunistic infections and an increased risk of mortality. HIV infection is also associated with on-going and aberrant activation of both the innate and adaptive immune systems. An important aspect of innate immune stimulation is derived from the leakage of lipopolysaccharide (LPS) across the damaged mucosal lining of the gut in early HIV infection. The impact of this innate immune stimulation on the adaptive arm of the immune system, as represented in this study by levels of CD4+ T-cell activation and death, have not been explored previously in untreated HIV infection. Using an integrated approach of immune activation, inflammation, oxidative stress and ameliorating antioxidant intervention for the first time, this thesis reports the impact of inflammatory induced-oxidative stress on CD4+ T-cells in an in vitro HIV model. In a preliminary study, baseline levels of neutrophil respiratory burst as an in vitro indication of immune stimulation were investigated. The relationships between baseline total antioxidant status (TAS), Red blood cell (RBC) antioxidant enzyme activities (catalase, superoxide dismutase & glutathione peroxidase), lipid peroxidation and glutathione redox ratio and other markers of disease in asymptomatic, untreated HIV infection were also explored. The design and optimization of an assay that could determine the effects of LPS-induced oxidative stress on CD4+ T-cells, was a critical part of this study. The development of this assay enabled the measurement of the effects of selected antioxidant interventions N-acetyl cysteine (NAC) and vitamin C, on LPS-induced CD4+ T-cell activation and death. The results were also correlated with CD4 count, viral load and markers of inflammation (fibrinogen & D-dimers) in HIV-infected and uninfected groups. Neutrophils from HIV-infected persons at rest showed a ―primed‖ response to low stimulating agent, bacterial N-formyl peptides (fMLP), which was significantly (P = 0.04) higher than uninfected individuals. There was increased oxidative stress as evidenced by increased catalase activity, malondialdehyde (MDA) and conjugated dienes (CDs) with a corresponding decrease in antioxidant capacity in HIV-infected individuals with lower CD4 count. NAC in combination with vitamin C, significantly (P = 0.0018) reduced activation of CD4+ T-cells to a greater degree than with either antioxidant alone. NAC and vitamin C individually and in combination significantly (P = 0.05, P = 0.012 and P<0.0001) decreased the expression of the markers of apoptosis, Annexin V and 7-amino-actinomycin (7-AAD). Importantly, the antioxidant combination decreased MDA values and significantly (P = 0.01) increased the glutathione redox ratio in the HIV-infected group. Based on these results, the respiratory burst and LPS-induced activation may be important contributing factors in inflammatory-associated oxidative stress in HIV infection and contribute to the depletion of CD4+ T-cells in the asymptomatic stage of HIV infection. These results also indicate the potential inhibitory effects of NAC and vitamin C in combination as agents that may limit immune activation and inflammation-induced oxidative stress. Importantly, the study showed that at this asymptomatic stage, CD4+ T-cells of the HIV-infected group responded similarly to stimulation as the HIV negative group, indicating that antioxidant defences were still functional and that appropriate early intervention at this stage may be protective against oxidative damage to the immune cells. To the best of our knowledge, this study is the first to use an integrated approach involving not only plasma levels of antioxidant status, but also RBC antioxidant enzyme activities, oxidative damage (lipid peroxidation), inflammation, cellular levels of immune activation and potential ameliorating interventions in evaluating the problem of inflammation-induced oxidative stress in HIV infection. Based on the results of this study, it is envisaged that an insight into the immune activation, inflammatory and oxidative stress status of patients will enable long-term profiling of each patient with a view to individualized therapy. This approach may have a direct impact on patient care in resource-limited settings such as sub-Saharan Africa. / AFRIKAANSE OPSOMMING: Chroniese inflammasie en immuunaktivering is kenmerke van MIV-infeksie. Dié twee prosesse lei tot chroniese oksidatiewe stres en oorbenutting van antioksidant verdedigingstelsels, wat lei tot die verlies van die immuun selle en vinniger siektevordering. Lae vlakke van antioksidante in MIV-positiewe individue stem ooreen met gereelde opportunistiese infeksies en 'n verhoogde risiko van mortaliteit. MIV-infeksie word ook geassosieer met langdurige en abnormale aktivering van beide die ingebore en aanpasbare immuunstelsels. 'n Belangrike aspek van ingebore immuun stimulasie in die raamwerk van vroeë MIV-infeksie, is die lekkasie van LPS oor die beskadigde slymvlies voering van die dunderm. Die impak van die ingebore immuun stimulasie op die aanpasbare arm van die immuunstelsel, soos aangetoon in hierdie studie deur die vlakke van CD4 T-sel aktivering en apoptose, is nog nie voorheen ondersoek in onbehandelde MIV-infeksie nie. Met behulp van 'n oorspronklike, geïntegreerde benadering van immuun aktivering, inflammasie, oksidatiewe stres en 'n lae vlak van antioksidant intervensie, lewer hierdie tesis verslag oor 'n in vitro model van inflammasie-geïnduseerde oksidatiewe stres op CD4 T-selle. In 'n voorlopige studie, is basislyn vlakke van die neutrofiel respiratoriese uitbarsting as 'n in vitro aanduiding van immuunstimulasie ondersoek. Die verhoudinge tussen basislyn totale antioksidant status (TAS), rooi bloed sel (RBC) antioksidant ensiemaktiwiteit (katalase, superoksied dismutase, en glutatioon peroksidase), lipied peroksidasie en glutatioon redoks-verhouding, asook ander merkers van siektevordering in asimptomatiese, onbehandelde MIV-infeksie is ook ondersoek. Die ontwerp en optimisering van 'n toets wat die effek van LPS-geïnduseerde oksidatiewe stres op CD4 T-selle kan bepaal, was 'n kritieke deel van hierdie studie. Die ontwikkeling van hierdie toets het ook die meting van die effek van toevoeging van twee geselekteerde anti-oksidante, N-asetiel sisteïen (NAC) en vitamien C, op LPS-geïnduseerde CD4 T-sel aktivering en apoptose ondersoek. Die resultate is ook gekorreleer met CD4-telling, virale lading en merkers van inflammasie (fibrinogeen en D-dimere) in groepe met en sonder MIV-infeksie. Neutrofiele van asimptomatiese persone met MIV infeksie, het 'n 'voorbereide' reaksie gehad teen ‗n lae stimulerende agent, bakteriële N-formiel peptied (fMLP), wat beduidend (P = 0,04) hoër was as in individue sonder MIV infeksie. Daar was verhoogde oksidatiewe stres soos bewys deur verhoogde katalase aktiwiteit, malondialdehied (MDA) en gekonjugeerde diëne (CDs), saam met 'n ooreenstemmende afname in anti-oksidant kapasiteit in MIV-positiewe individue met laer CD4-tellings. NAC in kombinasie met vitamien C, het die aktivering van CD4 T-selle beduidend verminder (P = 0,0018), 'n effek wat groter was in vergelyking met elke antioksidant alleen. NAC en vitamien C alleen, en in kombinasie het beduidend die uitdrukking van die merkers van apoptose, Annexin V en 7-AAD verminder (P = 0,05, P = 0.012 en P<0,0001). Wat belangrik is, is dat die afname in MDA waardes as gevolg van antioksidante in kombinasie, 'n beduidende styging in die glutatioon redoks verhouding in die MIV-positiewe groep tot gevolg gehad het. Hierdie resultate het aangetoon dat die respiratoriese uitbarsting en LPS-geïnduseerde aktivering belangrike bydraende faktore mag wees in inflammasie-verwante oksidatiewe stres in MIV-infeksie, wat kan bydra tot die uitputting van CD4 T-selle in die asimptomatiese stadium van MIV-infeksie. Hierdie resultate dui ook aan dat die moontlike inhiberende effekte van NAC en vitamien C in kombinasie, immuun aktivering en geïnduseerde oksidatiewe stres kan beperk. Van belang is die feit dat hierdie studie bewys het dat in die asimptomatiese stadium van MIV-infeksie, CD4 T-selle weens stimulasie dieselfde gereageer het as dié van mense sonder MIV infeksie. Dit het aangedui dat antioksidant verdediging in hierdie stadium nog funksioneel was, en dat 'n toepaslike vroeë intervensie op hierdie stadium beskermend teen immuun-sel oksidatiewe skade kan wees. Tot die beste van ons kennis, is hierdie studie die eerste om 'n geïntegreerde benadering te gebruik, waar plasma vlakke van antioksidant status saam met RBC antioksidant ensiemaktiwiteit, oksidatiewe skade (lipied peroksiidasie), inflammasie, sellulêre vlakke van immuunaktivering, en potensiële beskermende ingrypings ondersoek is in die evaluering van die probleem van oksidatiewe stres in MIV-infeksie wat tot inflammasie lei. Gebaseer op dié resultate, word dit in die vooruitsig gestel dat 'n insig in die status van immuunaktivering, inflammasie, en oksidatiewe stress van pasiënte, dit moontlik sal maak vir langtermyn- beplanning om vir elke pasiënt individuele terapie voor te skryf. Hierdie benadering kan 'n direkte impak op die sorg van pasiënte in hulpbron-beperkte gebiede soos sub-Sahara Afrika hê.

<p>The district health report for Livingstone, Zambia, outlined an increasing prevalence of HIV/AIDS iun the district. In 1998 the prevalence wsas at 29%, in 2000 at 30%, in 2002 at 31.8% and in 2004 at 31%. This was above the national prevalence of 20% according to CBoH statistics of 2004. The district has been implementing the HIV/AIDS prevention in various organizations during the past 3 years. Most of the organizations implementing the HIV/AIDS preventive activities do not work collaboratively with other sectors and this has resulted in un-coordinated activities and wstage of the limited resources. This exploratory qualitative study aimed at undestanding participants' perceptions of factors influencing coordination between different organizations that are involved in the implementation of HIV/AIDS activities, and to note the impact that this had in the implementation of activities in a multisectoral approach to HIV/AIDS prevention.</p>

Purpose: To describe the clinical presentation, ocular complications and clinical implications of acute HZO in HIV positive patients. Method: Prospective descriptive clinical case series of 54 individuals aged 18 – 50 years with confirmed HIV infection and acute presentation of HZO. Results: A female preponderance (1.7:1) and mean age of 36.6 years (range 18 – 49 years) was recorded. The majority of patients were referred from CHC and only 28% of referred patients received appropriate antiviral treatment at the referral site. Mean duration of rash at presentation was 4.7 days (range 1 – 12 days) with 31% of patients presenting within 3 days of rash eruption. Patients attended a mean of 2.7 clinical visits. Equal proportions had known and unknown HIV serostatus at presentation. Mean CD4+ was 276 cells/mm3 (range 44 - 859 cells/mm3). 67% of patients had a CD4+ count < 350 cells/mm3. Periocular discomfort was the most common presenting symptom (70%); decreased VA (2%) was an uncommon presenting symptom. Multidermatomal involvement was uncommon (7%). At presentation normal VA was seen in 69% of patients and 94% had no global visual impairment. Corneal complications (89%) and intraocular inflammation (46%) were the most common ocular complications. Ocular complications at presentation and multiple complications were the rule (70% and 61%). Hutchinson sign was found to be of little clinical value. Visual outcome was fair, 22% of patients having residual visual impairment. Post-herpetic neuralgia was common (74%). Conclusion: HZO is a common HIV marker condition with ocular complications. It may have an application as an indication for the initiation of ARV treatment.

A Research Report Submitted to the School of Public Health, University of the Witwatersrand, Johannesburg, in Partial Fulfilment of the Requirements for the Degree of Master of Science in Medicine in the Field of Epidemiology and Biostatistics: March 25, 2013 / Background: More than 33 million people are estimated to be living with HIV worldwide. Sub-Saharan Africa bears a disproportionate share of the global HIV burden. An estimated 15 million people living with HIV in low and middle income countries were in need of (HAART) in December 2009. HAART services require advanced laboratory technologies to monitor disease progression and therapeutic response, which are scarce in developing countries. Several simple and widely available markers have been proposed for use in low income countries including total lymphocyte count (TLC), haemoglobin and body mass index. Methodology: This study is a secondary data analysis of prospectively collected cohort data from HIV positive adults. The study measured the effect of exposure variables of haemoglobin (Hb) and body mass index (BMI). All cause mortality was the outcome of interest. Crude estimates of mortality were made with Kaplan-Meier mortality curves. Cox proportional hazards models were used to estimate adjusted hazard ratios. Exposure status was considered at initiation period. Outcomes were measured from two weeks post initiation of treatment to a maximum of two years of follow-up period. A composite score was developed to estimate the overall risk of mortality. Results: A total of 11,884 patients who satisfied the inclusion criteria were included in the analysis. A total of 1,305 deaths were observed during the follow-up period, representing 10.2% of the cohort at baseline. Most of the deaths were observed during the first four months of follow-up period. Patients with moderated to severe anaemia experienced 2.6 (HR = 2.6, 95% CI 1.8 - 3.6) times greater hazard of mortality adjusted for possible confounders. Patients with very iv low BMI experienced twice (HR=2.0, 95% CI 1.6, -2.5) greater hazard of mortality adjusted for a list of predictors. Race, age at initiation, employment status, smoking, alcohol consumption, baseline TB and baseline WHO stage did not show significant effect in the multivariate cox regression model. A composite score was developed to estimate the overall risk of mortality in patients based on measurements of baseline BMI and haemoglobin. Cox regression model adjusted for CD4 cell count shows high risk patients experienced 4.7 (HR = 4.7, 95% CI 2.9 – 7.6) times greater hazard of mortality compared to patients in the low risk group. Patients in the medium risk group experienced 3.4 (HR = 2.6, 95% CI 2.6 – 4.4) times greater hazard of mortality as opposed to patients in the low risk group. Conclusion: Haemoglobin and body mass index provide excellent prognostic information independent of CD4 cell count in HIV positive patients newly initiated on HAART. They can be used to reliably predict mortality. Combining measurements of haemoglobin and BMI through composite scoring improves their predictive ability. They can have good clinical application in rural and remote facilities to screen patients for clinical and diagnostic services.

Both HIV and tuberculosis (TB) have been documented to have detrimental effects on the nutritional status of those infected and nutritional status is a strong predictor of disease progression and survival. Body composition measures can be used as a proxy for nutritional status and takes into account body fat, muscle and water. It constitutes Fat Mass(FM), Fat Free Mass (FFM), Total Body Water (TBW), Extracellular Water (ECW), Intracellular water (ICW), Daily Energy Expenditure (DEE), Basal Metabolic Rate (BMR), phase angle and BMI which can be analysed as separate outcomes. Its use in evaluation of nutritional status has been reported to give more accurate results than the use of weight alone. We compared body composition measures and changes over a 12 month period in patients with HIV alone to patients with HIV and TB.

HIV-associated sensory neuropathy (HIV-SN) is a common complication associated with human immunodeficiency virus (HIV)-infection. A common symptom of HIV-SN is pain. Variation at specific loci within certain candidate genes has been suggested to alter susceptibility to developing HIV-SN as well as the susceptibility to developing pain and the intensity of the pain experienced. Few studies, however, have been conducted in individuals of black African ancestry. The aim of the current research was to conduct an in-depth study, in a black Southern African population, of genes previously associated with susceptibility to developing HIV-SN (TNFA and surrounding genes and IL12B) and variations in pain susceptibility and intensity (GCH1, KCNS1, IL1B, IL6, CCL2 and CCR2) in other neuropathic pain states. Single nucleotide polymorphisms (SNPs) identified in the literature were supplemented with population appropriate tagSNPs to improve assessment of the genes in an African population. Genotyping of previously collected deoxyribonucleic acid (DNA) samples was carried out using a GoldenGate assay with VeraCode microbeads and data were read on an Illumina BeadXpress Reader. Data were statistically analysed to assess the association of the genetic variants with susceptibility to developing HIV-SN and pain and variability of pain intensity in those patients with painful HIV-SN. Although some SNPs and haplotypes in the genes investigated associated with HIV-SN susceptibility (TNFA region), pain susceptibility (TNFA region, IL12B, KCNS1, IL6 and CCR2) or pain intensity (TNFA region, KCNS1, IL1B and IL6), none of the results were consistent with that which has been found in previous studies in non-African populations. Reasons for this may be that associations are population-specific or model-specific. Limitations of the study included the use of a relatively small sample, the method of sampling (convenience sampling), genotyping failure and tagging inefficiency in some instances, and the fact that there is no Southern African population dataset to use for tagSNP selection. My findings emphasise the importance of conducting genetic association studies in separate ethnic groups.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science in the School of Molecular and Cell Biology. Johannesburg, 2016. / Telomeres play significant roles in maintaining genome stability, regulating cell proliferation and apoptosis. The role of telomere biology and telomerase reactivation has been studied extensively in cancers. Telomerase has been previously associated with driving chronic kidney disease (CKD) advancement and most frequently due to HIV infection. However, the mechanism by which telomerase activation contributes towards disease progression beyond its canonical function of telomere maintenance is poorly understood. Telomerase is a ribonucleoprotein whose main function is telomere maintenance. Telomerase activity is dependent on expression of the rate-limiting human telomerase reverse transcriptase (hTERT) component. In addition to telomere maintenance, hTERT is implicated in other non-telomere related functions that promote cellular proliferation. Expression of hTERT is predominantly regulated at the transcription level where variation in promoter and minisatellite (MNS16A) sequences alter its expression. This variation has been implicated to confer susceptibility to diseases such as cancer and ageing disorders in non-African populations. Data on variation and pathogenicity of telomere-associated genes in African populations is limited and warrants further research. Thus bioinformatics analysis was performed to elucidate variation within the human TERT gene and promoter in different populations. The promoter, MNS16A and relative telomere length (RTL) were also evaluated in 159 African study participants with and without CKD. TERT common variants are equally distributed across populations with limited data on connection to the effects of the variants in African populations. Further bioinformatics analyses revealed significant difference (p<0.0001) in distribution of promoter variant rs2853669 between African and non-African populations. No common promoter mutations were identified in our study population. Interestingly, the long MNS16A variant suggested to increase TERT expression was significantly overrepresented in individuals with CKD regardless of HIV status. For the first time, a strong association of the long MNS16A variant with CKD regardless of HIV status is reported, implicating MNS16A as a potential risk factor in CKD.

M.Sc.(Med.) (Population Based Field Epidemiology) / Background Assessing HIV incidence over time in a rural population, largely characterized by high levels of migration and poverty is important to understand the dynamics of the spread of HIV infection. Understanding patterns of HIV infection is a key to defining the appropriate strategies for prevention of the disease especially in areas where information on HIV incidence is scarce, such as in Africa and South Africa in particular. Objectives and methods The main objective of this study is to measure the association between migration history and newly acquired HIV infection by sex. The specific objectives are to: (i) quantify median distance of migration by members of the cohort during the period of observation; (ii) measure the association between migration status and acquisition of HIV infection among males and females study participants. The current analysis is based on secondary data collected at the Africa Centre Demographic Surveillance System (DSS) in South Africa. Women aged 15-49 years and men aged 15-54 years were enrolled in the study and tested for HIV between 2003/5 and 2008. A Weibull survival model was used to determine the probability of HIV infection, subject to migration and possible confounders. Results For external migration, the median of external in-migration distance was 53.9 km, with a lower quartile of 27 km and upper quartile of 204 km while the median of external out-migration distance was 104.7 km, with a lower quartile of 52 km and upper quartile of 204 km. The total migration rate among males is 8.8 and for females the rate is 8.2 per 100 person-years (PYO). The majority of external migrants moved to Durban, which appeared to be the most important origin and destination for most migrants. Of the 9300 individuals enrolled in this study, 699 sero-converted. The HIV incidence rate among non-migrants males was 2.0/100 PYO (95% CI, 1.7 – 2.3) and for non-migrants females was 4.1/100 PYO (95% CI, 3.8 – 4.5) while the HIV incidence rates among migrants were higher for females in all categories: 2.0/100 PYO (95% CI, 1.3- 3.1) among internal migrants, 3.8/100 PYO (95% CI, 1.7- 8.5) for external in-migrant and among external out-migrants the HIV incidence rate was 3.2/100 PYO (95% CI, 2.3 – 4.5). For both genders, except internal migration showed a significant risk of HIV acquisition, other types of migration showed no significant association with HIV acquisition. Among other predictors, males who were in the age group 25-29 had the highest hazard of 3.75 times increased risk of HIV acquisition compared to the age group 15-19 [HR = 3.75, 95% CI (2.30 – 6.32), P < 0.001]. Females aged 20-24 years had 43% increased risk of HIV acquisition compared to the those aged 15-19 years [HR = 1.43, 95% CI (1.13 – 1.79), P = 0.002]. For marital status, females who had never been married and not engaged had 71% increased risk of HIV acquisition compared to those who were married, [HR = 1.71, 95% CI (1.09 – 2.68), P = 0.019]. Females with conjugal partners who were always resident and females with conjugal partners who were partial resident had a reduced risk of HIV acquisition of 41% [HR = 0.59, 95% CI (0.36 – 0.95), P = 0.031] and 38% [HR = 0.62, 95% CI (0.40 – 0.96), P = 0.034] respectively. Conclusion Rates of migration vary by age and gender in this cohort of repeat-testers of HIV. Younger individuals migrated more often and the majority of migrants moved to urban centres close to the study area. In terms of HIV incidence, for all covariates, females had higher rates of HIV acquisition than males. External migration does not appear to increase HIV acquisition for this cohort of repeat-testers of HIV, and those who internally migrated had a reduced risk of HIV acquisition. Based on these findings, public health efforts aimed at controlling the spread of HIV infection in this cohort should target at socio-economic condition, sexual behaviour and empowering of women in particular.