The objective of this study was to assess levels of HAART adherence and factors affecting it. An observational, analytic, cross-sectional and quantitative study using IMB model was conducted on a randomly selected 349 HIV/AIDS patients on a HAART regimen. Data collection was done by interviewing respondents using a structured questionnaire. Both descriptive and inferential statistics used in the study. Only 80.2% of the total sample population reported a HAART adherence rate of more than or equal to 95% in this study. The findings highlight the need for on-going educational, informational and other interventions to address the knowledge, motivation and adherence behavioural skills of patients in order to improve the current levels of HAART adherence behaviour. The study also suggested the need for research into objective measures of adherence as well as longitudinal studies on adherence behaviour because strict adherence to treatment is a long-term process and not a one-time activity. / Health Studies / M.A. (Public health)

M.A. (Public Management and Governance) / This study starts with an introduction and background, and this is followed by a statement of the research problem, research rationale, research objectives, research design, research methodology and the data collection methods. A list of acronyms will be provided, as well as an overview of chapters, conclusions, and acknowledgements. “Around 5.7 million in 2009 had contracted HIV and AIDS and in the preceding year 250,000 South Africans died due to HIV/AIDS related diseases. All age categories and gender are prone to contracting the disease and the resultant loss of life has had a devastating effect on the workforce. Death due to this disease has caused loss of income and family disintegration” (Sottile 2013:2). In 2010, some 280,000 South Africans died of HIV/AIDS. In the decade up to 2010, between 42% and 47% of all deaths among South Africans were HIV/AIDS-related deaths (Sottile 2013:2). Mlambo et al (2011:1) further say that “The Human Sciences Research Council estimates that 10.9% of all South Africans have HIV/AIDS. Additionally, the Central Intelligence Agency estimates that 310,000 individuals died in South Africa from HIV/AIDS in the year 2009”. A study in 2003 made a comparison on two scenarios, an HIV/AIDS scenario and a no-HIV/AIDS scenario and this was based on the annual growth rates between 2002 and 2015. The finding was that “real growth in GDP would be 0.6% lower than if there were no HIV/AIDS, but per-capita growth in GDP would be 0.9% higher. Growth in population would have been 1.5% lower, and growth of the labour force would be 1.2% lower, but the unemployment rate would be 0.9% lower as well” (Avert.Org 2010:2). Different HIV/AIDS prevention strategies are being implemented in South Africa. The focus in this study is on male medical circumcision (hereafter MMC), which is the removal of all or part of the foreskin on the penis. It can either be performed surgically in hospitals or at initiation schools. Initiation schools perform the procedure as a traditional rite of passage from boyhood to manhood, and this is referred to as traditional male circumcision (TMC). This practice has up till now been performed purely for traditional or religious purposes, but it can no longer be viewed only as such. It should, instead, also be seen as a measure to curb the spread of the HIV/AIDS pandemic. A number of observational studies (which will be referenced later) found that circumcised men had smaller chances of contracting HIV infection compared with uncircumcised men...

The introduction of antiretroviral drugs (ARVs) in 1996 transformed the treatment of HIV and AIDS, improving the quality and greatly prolonging the lives of many infected people. HIV (Human Immunodeficiency Virus) is the virus that is believed to cause AIDS. AIDS (Acquired Immune Deficiency Syndrome) is the collection of illnesses or symptoms that ultimately results in death. Antiretroviral (ARVs) drugs or Highly Active Antiretroviral Therapy (HAART) is the treatment that has been applied to combat the HI virus in a bid to slow down the progression of AIDS and ultimately prolong the life of the infected individual. The study aimed to explore and describe the factors contributing to adherence and non-adherence to ARVs in individuals on treatment. A sample of 81 individuals who have been on ARV and HAART treatment for six months or more was used. The methodology used was exploratory-descriptive and the data obtained was quantitative in nature. A biographical questionnaire and questionnaire with questions aimed at ascertaining the possible factors that contribute to individuals either adhering to or defaulting on their treatment, such as side effects and cost of treatment, was administered. The data obtained was analysed by means of descriptive statistics and frequency counts. The results of the study showed that the sample had a fairly high level of adherence. The factors that could undermine adherence were identified as lack of support, as familial and health provider support acts as a motivator to adhere; substance abuse as it can lead to forgetting to take treatment; unemployment and poverty, as these can lead to an inability to return for follow up clinic visits or failure to have food to take with the pills; and the type of treatment regimen whereby the more complex the treatment is the more likely it is that adherence will be difficult to maintain. Suggestions were made as to future research involving antiretroviral therapy (ART). Finally the limitations as well as the value of the research were outlined.

This study has focused on the synthesis of truncated analogues of the hydroxyethylene dipeptide isosteres, such as Ritonavir®, currently in clinical use as HIV-1 protease inhibitors. The reactions of pyridine-2- and quinoline-2-carbaldehydes with methyl acrylate, in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) or 3- hydroxyquinuclidine (3-HQ) as nucleophilic catalysts, have afforded a series of Baylis- Hillman adducts, acetylation and cyclisation of which have provided access to a series of indolizine-2-carboxylate esters. The carboxylic acids, obtained by base-catalyzed hydrolysis of these esters, have been coupled with various protected (and unprotected) amino compounds using the peptide coupling agent, 1,1’-carbonyldiimidazole (CDI), to afford a series of indolizine-2-carboxamides as indolizine-based truncated Ritonavir® analogues in quantitative yield. Aza-Michael reactions of pyridine-3-carbaldehydederived Baylis-Hillman adducts with various amino compounds have provided access to a range of pyridine-based products as mixtures of diastereomeric aza-Michael products. The assignment of the relative stereochemistry of the aza-Michael products has been established using 1-D and 2-NOESY experiments and computer modelling techniques. Computer modelling studies have also been conducted on selected aza-Michael products using ACCELRYS Cerius2 software, followed by interactive docking into the HIV-1 protease receptor site, using AUTODOCK 4.0. The docking studies have revealed hydrogen-bonding interactions between the enzyme and the synthetic ligands. Saturation Transfer Difference (STD) NMR experiments have also indicated binding of some of the aza-Michael products to the HIV-1 protease subtype C enzyme, thus indicating their binding and possible inhibitory potential.

The project has focused on the preparation of several series of compounds designed as potential HIV-1 integrase inhibitors. Various 2-nitrobenzaldehydes have been reacted with two activated alkenes, methyl vinyl ketone (MVK) and methyl acrylate, under Baylis-Hillman conditions to afford α-methylene-β-hydroxylalkyl derivatives in moderate to excellent yields. The reactions were conducted using the tertiary amine catalysts, 1,4-diazabicyclo[2.2.2]octane(DABCO) or 3-hydroxyquinuclidine (3-HQ) with chloroform as solvent, and yields were optimised by varying the catalyst, reagent concentrations and the reaction time. Reductive cyclization of the Baylis-Hillman adducts via catalytic hydrogenation, using 10% palladiumon-carbon catalyst in ethanol, afforded quinoline and quinoline N-oxide derivatives. In some cases “acyclic” reduction products were also isolated. Reaction of the Baylis-Hillman MVK adducts with HCl, has resulted in effective nucleophilic (SN’) displacement of the hydroxyl group to afford allylic chloride derivatives. Direct substitution of these chloro derivatives by secondary or primary amines, followed by catalytic hydrogenation gave quinoline derivatives containing a 3-aminomethyl substituent. The Baylis-Hillman ester adducts obtained from reaction with methyl acrylate were treated directly with various amines to give diastereomeric conjugate addition products. Reactions with piperazine gave N,N’-disubstituted piperazine products. The piperidine derivatives have been dehydrated to give cinnamate esters in moderate yields. The products, which have all been satisfactorily characterised by elemental (HRMS) and spectroscopic (1- and 2-D NMR) analysis, constitute a “library” of compounds for in silico and in vitro studies as potential HIV integrase inhibitors.

This study has involved the design, synthesis and evaluation of novel HIV-1 enzyme inhibitors accessed by synthetic elaboration of Baylis-Hillman adducts. Several series of complex coumarin-AZT and cinnamate ester-AZT conjugates have been prepared, in high yields, by exploiting the click reaction between appropriate Baylis-Hillman derived precursors and azidothymidine (AZT), all of which have been fully characterised using spectroscopic techniques. These conjugates, designed as potential dual-action HIV-1 inhibitors, were tested against the appropriate HIV-1 enzymes, i.e. HIV-1 reverse transcriptase and protease or HIV-1 reverse transcriptase and integrase. A number of the ligands have exhibited % inhibition levels and IC50 values comparable to drugs in clinical use, permitting their identification as lead compounds for the development of novel dual-action inhibitors. In silico docking of selected ligands into the active sites of the respective enzymes has provided useful insight into binding conformations and potential hydrogen-bonding interactions with active-site amino acid residues. A series of furocoumarin carboxamide derivatives have been synthesised in four steps starting from resorcinol and these compounds have also been tested for HIV-1 integrase inhibition activity. The structures of unexpected products isolated from Aza-Baylis-Hillman reactions of N-tosylaldimines have been elucidated by spectroscopic analysis, and confirmed by single crystal X-ray analysis. A mechanism for what appears to be an unprecedented transformation has been proposed. Microwave-assisted SeO₂ oxidation of Baylis-Hillman-derived 3-methylcoumarins has provided convenient and efficient access to coumarin-3-carbaldehydes, and a pilot study has revealed the potential of these coumarin-3-carbaldehydes as scaffolds for the construction of tricyclic compounds. The HCl-catalysed reaction of tert-butyl acrylate derived Baylis-Hillman adducts has been shown to afford 3-(chloromethyl)coumarins and α-(chloromethyl)cinnamic acids, the Zstereochemistry of the latter being established by X-ray crystallography. ¹H NMR-based experimental kinetic and DFT-level theoretical studies have been undertaken to establish the reaction sequence and other mechanistic details. Base-catalysed cyclisation on the other hand, has been shown to afford 2H-chromene rather than coumarin derivatives.

AIDS Dementia Complex (ADC) is a neurodegenerative disorder implicated in HIV-1 infection that is associated with elevated levels of the neurotoxin, quinolinic acid (QA) which causes a cascade of events to occur, leading to the production of reactive oxygen species (ROS), these being ultimately responsible for oxidative neurotoxicity. In clinical studies, Non-nucleoside reverse transcriptase inhibitors (NNRTIs), efavirenz (EFV) and nevirapine (NVP) have been shown to potentially delay the progressive degeneration of neurons, thus reducing the frequency and neurological deficits associated with ADC. Despite these neuroprotective implications, there is still no biochemical data to demonstrate the mechanisms through which these agents offer neuroprotection. The present study aims to elucidate and further characterize the possible antioxidant and neuroprotective mechanisms of NVP and EFV in vitro and in vivo, using QA-induced neurotoxicity as a model. Research has demonstrated that antioxidants and metal chelators have the ability to offer neuroprotection against free radical induced injury and may be beneficial in the prevention or treatment of neurodegeneration. Hence the antioxidant and metal binding properties of these agents were investigated respectively. Inorganic studies, including the 1, 1-diphenyl-2 picrylhydrazyl (DPPH) assay, show that these agents readily scavenge free radicals in vitro, thus postulating the antioxidant property of these agents. The enhancement of superoxide radical generation and iron mediated Fenton reaction by QA is related to lipid peroxidation in biological systems, the extent of which was assayed using the nitroblue tetrazolium and thiobarbituric acid method respectively. Both agents significantly curtail QA-induced lipid peroxidation and potentially scavenge superoxide anions generated by cyanide in vitro. Furthermore, in vivo results demonstrate the ability of NVP and EFV to protect hippocampal neurons against lipid peroxidation induced by QA and superoxide radicals generated as a consequence thereof. The alleviation of QA-induced oxidative stress in vitro possibly occurs through the binding of iron (II) and / or iron (III), and this argument is further strengthened by the ability of EFV and not NVP to reduce iron (II)-induced lipid peroxidation in vitro directly. In addition the ferrozine and electrochemistry assay were used to measure the extent of iron (II) Fe[superscript 2+] and iron (III) Fe[superscript 3+] chelation activity. Both assays demonstrate that these agents bind iron (II) and iron (III), and prevent redox recycling of iron and subsequent complexation of Fe[superscript 2+] with QA which enhances neuronal damage. Both NNRTIs inhibit the endogenous biosynthesis of QA by inhibiting liver tryptophan 2, 3-dioxygenase activity in vivo and subsequently increasing hippocampal serotonin levels. Furthermore, these agents reduce the turnover of hippocampal serotonin to 5-hydroxyindole acetic acid. NVP and not EFV increase 5-hydroxyindole acetic acid and norepinephrine levels in the hippocampus. The results of the pineal indole metabolism study show that NVP increases the synthesis of melatonin, but decreases N-acetylserotonin, 5-hydroxyindole acetic acid and 5-hydroxytryptophol levels. Furthermore, it shows that EFV decreases 5-hydroxyindole acetic acid and melatonin synthesis. Behavioural studies using a Morris water maze show that the post-treatment of rats with NVP and EFV significantly improves QA-induced spatial memory deficits in the hippocampus. This study therefore provides novel information regarding the neuroprotective mechanisms of NVP and EFV. These findings strengthen the argument that these NNRTIs not only have antiviral effects but possess potential neuroprotective properties, which may contribute to the effectiveness of these drugs in the treatment of ADC.

Approximately 33.4 million people are living with HIV/AIDS. Of those, 97% live in low and middle income countries, with 22.4 million in sub-Saharan Africa. Only 42% of the people who require anti-retrovirals (ARVs) in low to middle income countries are receiving anti-retroviral therapy (ART). There is a need to develop novel and cost effective methods for producing antiretroviral drugs. Stavudine and azidothymidine (AZT) were identified as potential targets because they could both be produced through a common intermediate – 5 methyluridine (5-MU). It has been established that the biocatalytic production of 5-methyluridine is possible through a reaction known as transglycosylation, in a process which has not previously been demonstrated as commercially viable. A selection of biocatalysts were expressed either in recombinant E. coli strains or in the wild type organisms, purified and then screened for their ability to produce 5-MU. A combination of Bacillus halodurans purine nucleoside phosphorylase 1 (BHPNP1) and E. coli uridine phosphorylase (EcUP) gave the highest 5-MU yield (80%). This result represents the first combination of free enzymes from different organisms, giving high yields of 5-MU under high substrate conditions. Both enzymes were purified and successfully characterised. The established pH optimum was pH 7.0 for both enzymes. Temperature optima and stability data for BHPNP1 (70 C and t1/2 at 60 C of 20.8 h) indicated that the biocatalytic step was operating within the capabilities of this enzyme and would operate well at elevated temperatures (up to 60 C). Conversely, the temperature optimum and stability data for EcUP (optimum of 40 C and t1/2 at 60 C of 9.9 h) indicated that the enzyme remained active at 40 C for the duration of a 25 h biotransformation, but at 60 C would only be operating at 20% of its optimum activity and would lose activity rapidly. BHPNP1 and EcUP were used in a bench scale (650 ml) transglycosylation for the production of 5-MU. A 5-MU yield of 79.1% was obtained at this scale with a reactor productivity of 1.37 g.l-1.h-1. Iterative saturation mutagenesis was used to rapidly evolve EcUP for improved thermostability. A moderately high throughput colorimetric method was developed for screening the mutants based on the release of p-nitrophenol upon phosphorolysis of a pyrimidine nucleoside analogue. By screening under 20 000 clones the mutant UPL8 was isolated. The mutant enzyme showed an optimum temperature of 60 C and improved stability at 60 C (t1/2 = 17.3 h). The increase in stability of UPL8 is due to only 2 mutations (Lys235Arg, Gln236Ala). These mutations may have caused an increase in stability due to interactions with other structural units in the protein, stabilization of the entrance to the binding pocket, or by decreasing the flexibility of the α-helix at the N-terminus. Transglycosylation experiments showed that the mutant enzyme UPL8 is a superior catalyst for the production of 5-MU. A 300% increase in reactor productivity was noted when free enzyme preparations of UPL8 was combined with BHPNP1 at 1.5% m.m-1 substrate loading. The high yield of 5-MU (75-80% mol.mol-1) was maintained at 9% m.m-1 substrate loading. A commercially viable productivity of 31 g.l-1.h-1 was thus realised. Further optimisation of the process could produce still higher productivities. Future work in directed evolution of nucleoside phosphorylases is envisaged for improved stability and enhanced substrate range for application to other commercially relevant transglycosylation reactions.

Despite the current interventions to avert contagions and AIDS-related deaths, sub-Saharan Africa is still the region most severely affected by the HIV/AIDS pandemic, where clade C is the dominant circulating HIV-1 strain. The pol-encoded HIV-1 protease enzyme has been extensively exploited as a drug target. Protease inhibitors have been engineered within the framework of clade B, the commonest in America, Europe and Australia. Recent studies have attested the existence of sequence and catalytic disparities between clades B and C proteases that could upset drug susceptibilities. Emergence of drug-resistant associated mutations and combinatorial explosions due to recombination thwarts the attempt to stabilize the current highly active antiretroviral therapy (HAART) baseline. The project aimed at identifying the structural and molecular mechanisms hired by mutants to affect the efficacies of both FDA approved and Rhodes University (RU)-synthesized inhibitors, in order to define how current and or future drugs ought to be modified or synthesized with the intent of combating drug resistance. The rationale involved the generation of homology models of the HIV-1 sequences from the South African infants failing treatment with two protease inhibitors: lopinavir and ritonavir (as monitored by alterations in surrogate markers: CD4 cell count decline and viral load upsurge). Consistent with previous studies, we established nine polymorphisms: 12S, 15V, 19I, 36I, 41K, 63P, 69K, 89M, and 93L, linked to subtype C wild-type; some of which are associated with protease treatment in clade B. Even though we predicted two occurrence patterns of M46I, I54V and V82A mutations as V82A→I54V→M46I and I54V→V82A→M46V, other possibilities might exist. Mutations either caused a protracted or contracted active site cleft, which enforced differential drug responses. The in silico docking indicated susceptibility discordances between clades B and C in certain polymorphisms and non-polymorphisms. The RU-synthesized ligands displayed varied efficacies that were below those of the FDA approved protease inhibitors. The flaps underwent a wide range of structural motions to accommodate and stabilize the ligands. Computational analyses unravelled the need for these potential drugs to be restructured by (de novo) drug engineers to improve their binding fits, affinities, energies and interactions with multiple key protease residues in order to target resilient HIV-1 assemblages. Accumulating evidences on contrasting drug-choice interpretations from the Stanford HIVdb should act as an impetus for the customization of a HIVdb for the sub-Saharan subcontinent.

Thesis (Ph.D. (Physiology and Environmental Health)) -- University of Limpopo, 2021 / Background: Human immunodeficiency virus (HIV)-infection remains a major public health burden where approximately 38 million people are affected globally. Human immunodeficiency virus infection is associated with chronic inflammation which can lead to endothelial dysfunction and thrombosis, which are precursor events for cardiometabolic abnormalities such as dysglycaemia and dyslipidaemia. The degree of chronic inflammation, endothelial dysfunction, and hypercoagulation among HIVpositive adults on highly active antiretroviral therapy are not well understood in Sub- Saharan Africa. The objective of this study was to determine the effect of highly active antiretroviral therapy (HAART) on chronic inflammation, endothelial dysfunction, and hypercoagulation among HAART-exposed adult South African participants in a rural setting. Aim: The study aimed to determine the effects of HAART on early biomarkers of cardiovascular disease in the HIV-positive subjects. Methods: The study was cross-sectional, descriptive, and quantitative in design. The research population consisted of 158 participants of males and females within the age range of 18 – 81 years from Mankweng Hospital and surrounding clinics. The study population comprised of three groups, HIV-negative (control group), HIV-positive treatment naïve (HAART-naïve group), and HIV-positive participants on HAART (HAART-exposed group). Weight and height were measured using Omron BF 400 and a portable stadiometer respectively, to calculate the body mass index. Glucose and lipid levels were determined on Cobas® Integra 400 plus auto-analyser. The CD4+ T cell count was determined on the Cytomics FC500 Flow Cytometer Multi-Platform loader. The concentration of fibrinogen, c-reactive protein (CRP), L-selectin, D-dimers, P-selectin, von Willebrand factor (VWF), soluble intercellular adhesion molecule (sICAM-1), and soluble vascular cell adhesion molecule (sVCAM-1) in serum samples were determined on the Luminex 200TM. Data were analysed using SPSS version 25.0. Descriptive statistics were performed on all variables and analysis of covariance was used to determine differences across all groups. Correlation coefficients and multiple regression analyses were used to determine associations. Results: Body mass index (BMI) and glucose metabolism were not significantly affected by HAART exposure. However, the HAART-exposed group had significantly increased LDL-C (F (2, 154) = 7.501, p = 0.001) and TC (F (2, 154) = 9.174, 0.0002) levels. The prevalence of high LDL-C levels was significantly elevated in the HAART-exposed group (29.6%) (p = 0.041). The prevalence of pre-diabetes (11.3%) was the highest among the HAART-exposed group (non-significant), although, no significant difference was observed. While P-selectin was significantly reduced in the HAART-exposed group (F (2, 154 = 7.253, p = 0.001). On the other hand, the HAARTexposed group also significantly increased VWF (F (2, 154 = 4.556, p = 0.011). The HAART-exposed group showed no significant effect on L-selectin, sICAM-1, sVCAM- 1, CRP, fibrinogen and D-dimer levels. However, D-dimer was negatively associated with HAART (r = -0.249, p = 0.011). There were significant independent association between the combined HAART regimens and P-selectin (Std β = 0.219, p = 0.032), first-line regimen with both P-selectin (Std β = 0.434, p = 0.004) and sVCAM-1 Std β = 0.328, p = 0.031), second-line regimens with L-selectin (Std β = 1.032, p = 0.005) and, a positive independent association between first-line regimen and D-dimer (β = 0.741, p = 0.0001). Although BMI and glucose metabolism were not significantly affected in both the HAART-exposed and HAART-naïve groups, dyslipidaemia was present across the three groups (HAART-exposed, HAART-naïve and control). HAART-exposure showed a protective effect by reducing endothelial dysfunction (ED) and hypercoagulation. Yet, ED was still present among this rural South African HAART-exposed population. The HAART-exposed group may be at increased risk for CVD. Therefore, CVD should be regularly monitored in the HAART-exposed population. / National Research Fund, the Health and Welfare Sector Education and Training Authority, and the University of Limpopo (UL)