Electronic Theses and Dissertations (Masters)
Permanent URI for this collectionhttps://hdl.handle.net/10539/37984
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Item Design and engineering of a bio-responsive, nano-enabled vitreous substitute for the treatment of retinal diseases(University of the Witwatersrand, Johannesburg, 2023-07) Naik, Kruti; Du Toit, Lisa C.; Choonara, Yahya E.The vitreous humour is a soft gel between the lens and the retina in the eye. It protects the surrounding ocular tissues functioning as a shock absorber and a vessel for oxygen and metabolite transport. Vitreous liquefaction leads to vitreous detachment resulting in ocular tissue damage such as retinal detachment and vitreous haemorrhage. Current treatment includes total vitreous replacement via pars plana vitrectomy utilising silicone oil. Cataracts, inflammation, and retinal toxicity as a result of silicone oil treatment have led to the need for a more effective long-term vitreous substitute. It is essential to treat vitreoretinal diseases concurrently with vitreous substitution. This study aimed to investigate and design the proposed concept of a thermoresponsive, nano-enabled vitreous substitute for the treatment of retinal diseases. An initial study in the selection of polymers for the hydrogel identified a blend of natural and synthetic polymers. Hyaluronic acid with a blend of two poloxamers of differing molecular weights were identified and optimisation allowed for their selection prior to nanoparticle loading and characterisation. Poly(ᴅ,ւ-lactide-co-lycolide) acid nanoparticles encapsulating triamcinolone acetonide were synthesised with a spherical morphology and mean diameter of 153 nm allowing nanoparticle penetration into the retinal layers from the vitreous. Hydrogel fabrication and nanoparticle loading within the hydrogel was confirmed via physicochemical analysis. Gelation studies indicated that hydrogels formed in nine minutes and 10 minutes for the unloaded and nanoparticle-loaded hydrogels respectively. The hydrogels displayed in situ formation properties and rheometric viscoelastic studies indicated the unloaded and loaded hydrogels to have modulus values similar to those of the natural vitreous at 37 °C. Administration of the hydrogels was possible via 26G needles allowing for clinical application and drug release of triamcinolone acetonide from the nanoparticle-loaded hydrogel indicated that a sustained drug release was visible over nine weeks. The hydrogels displayed minimal swelling, reaching equilibrium swelling within 12 hours for the unloaded hydrogel and eight hours for the nanoparticle-loaded hydrogel. Biodegradation in simulated vitreous humour with lysozyme showed < 20% degradation within nine weeks. Biocompatibility of both hydrogels was shown with mouse fibroblast and human retinal pigment epithelium cell lines. Lastly, a pilot in vivo study with a New Zealand White rabbit model displayed minimal toxicity with localised drug release behaviour. In conclusion, the unloaded and nanoparticle-loaded hydrogels developed in this research demonstrate their potential as vitreous substitutes that function as drug delivery systems following vitrectomy surgery.Item Incidences associated with enalapril-induced angioedem in a public regional hospital, Limpopo Province (South Africa)(University of the Witwatersrand, Johannesburg, 2023-10) Muremela, Blessing; Bangalee, Varsha; Padayachee, NeelaveniBackground: The study explored enalapril-induced angioedema reactions at Tshilidzini Regional Hospital (South Africa), from January 2017 to December 2019. The aim was to identify and describe incidences of enalapril- induced angioedema in a public regional hospital, over a three-year period. Materials and Methods A retrospective record review was undertaken at Tshilidzini Hospital. Data were collected from medical files of patients who had experienced enalapril-induced angioedema, between January 2017 to December 2019. Cases were retrieved using the pharmacovigilance ADR database records. Demographic information, medical history, clinical presentations, therapeutic management and outcomes were collected and consolidated on a data collection tool. A Microsoft Excel spreadsheet was used to record the information which was then interpreted utilizing the Statistical Package for Social Sciences (SPSS) version 29. Ethical clearance was acquired from the University of the Witwatersrand Human Research Ethics Committee (Medical). Results: Forty cases (37.3%) of enalapril-induced angioedema were included out of a total of hundred and seven cases reviewed from the Pharmacovigilance ADR database records. The results indicated that demographic details - gender, age and race - affected the incidence of enalapril-induced angioedema. Out of the forty cases, most were female (95%) and between the ages of 50-59 (25%) and 70-79 (25%). Majority of the participants presented with swollen lips (34%) and tongue (24%) as clinical presentations of enalapril- induced angioedema. All participants were counselled and they discontinued enalapril after the incident. Hospitalization occurred in 15% of the participants and death occurred in 5% of the participants. Conclusion: Amongst the cases reviewed, swelling of the lips and tongue was reported to be the most common clinical presentation of enalapril-induced angioedema. The study findings suggest a need for awareness among all healthcare professionals, so that they could identify and treat enalapril-induced angioedema as well as report all incidences. ACE-induced angioedema may be occurring more regularly but may not be known due to misdiagnosis and underreporting by healthcare professionals. This shows that healthcare professionals must constantly be conscious about the significance of reporting enalapril-induced angioedema to improve patients’ safety and treatment outcomes. More reporting of incidences and further research is required for healthcare professionals to become knowledgeable about this life-threatening condition.Item Experience of bowel, bladder and sexual problems and the effectiveness of a health program on quality of life and mental health in people with spinal cord injury in Manguzi(University of the Witwatersrand, Johannesburg, 2023) Tomes, Lauren Meagan; Sonti PilusaBackground: The quality of life of people with spinal cord injury is significantly affected by secondary health conditions such as bowel, bladder, and sexual problems. Literature on the experiences of bowel, bladder, and sexual problems is limited and studies on health interventions in people with SCI are also scarce in South Africa. Aim: To explore the experience of bowel, bladder and sexual problems and the effectiveness of a health program on the quality of life and mental health, as well as to determine the effectiveness of a health program on the quality of life (QoL) and mental health of people with SCI in Manguzi, KwaZulu Natal. Method: This study was a mixed study. An explorative qualitative study design using semi structured interviews was employed. The interviews were transcribed verbatim, and content analysis was conducted to identify the themes and categories. A Quasi-Experimental quantitative design was used. A face-to-face health program on the prevention and management of bowel, bladder, and sexual problems in SCI was conducted for the participants with SCI. WHOQoL Bref and SF-12 questionnaires were administered before and six weeks post-intervention respectively. Paired t-test was used to identify changes in QOL and mental health pre and post intervention. Significance was set at p-value ≤ 0.05. Results: The themes that emerged from the experience of bladder and bowel problems were “no control” and “frustration”. The categories related to the experiences were: types of bladder and bowel problems, managing bladder and bowel problems and the effects on well-being: The main theme for the experience of sexual health problems was “Dissatisfaction”. The categories were: types of sexual health problems, factors influencing sexual activity, the impact of sexual problems, and the management of sexual health problems. The long-term care needs for bowel and bladder problems included access to proper toilets, nappies, medication (Dulcolax), ease of bowel movement, and health information on diet and how to manage their bowel and bladder problems better. The long-term care needs for sexual health problems included the need for medication (sexual enhancement pills) and information on how to manage sexual health problems. There were no statistically significant changes in the pre-test and post-test scores of both the quality of life and mental health.Item An evaluation of the effects of metal complexes on lung cancer cell lines(University of the Witwatersrand, Johannesburg, 2024) Mangena, Zanele; Harmse, LeonieLung cancer remains a predominant global health concern, accounting for approximately 18% of cancer-related deaths. In South Africa, it imposes a significant burden due to high rates of late-stage diagnoses, resulting in compromised survival outcomes. Despite available targeted therapies, treatment efficacy is hindered by drug resistance and severe side effects, highlighting the need for alternative agents. This study aimed to investigate a series of complexes in an in vitro setting to assess their potential as alternative agents for lung cancer therapy. This study evaluated 20 compounds, encompassing novel epidermal growth factor receptor kinase inhibitors, AD and OM copper complexes, and copper imidazo[1,2-a]pyridines in vitro. Their cytotoxicity against A549 lung cancer cells was determined by the MTT assay, and the most potent compounds were chosen for further investigation. The mode of cell death for these compounds was assessed through cell morphology, Annexin-V, caspase-3/7, mitochondrial membrane potential, and caspase-8 assays. The capacity of the active compounds to induce reactive oxygen species was measured through the CellROX™ Deep Red assay kit. Immunohistochemistry techniques were employed to analyze the expression and distribution of p21 and p53. Furthermore, changes in the expression levels of apoptosis-related proteins post-treatment with the most effective compound were assessed using the Proteome Profiler Human Apoptosis Array kit. Four copper-imidazo[1,2-a]pyridines, namely JD35, JD46, JD47, and JD88, were the most active, with IC50 values in A549 cells between 1.67 μM and 3.37 μM. These compounds induced apoptotic cell death, characterized by chromatin condensation, fragmented nuclei, Annexin-V binding, and activation of caspase-3/7. They also caused a decline in mitochondrial membrane potential, indicating activation of the intrinsic apoptotic pathway, while also inducing late caspase-8 activation. Furthermore, these compounds enhanced reactive oxygen species and upregulated nuclear p21 and p53 expression, suggesting DNA damage leading to apoptosis initiation. Analysis of apoptotic proteome array data showed that JD88 treatment significantly upregulated the wild-type tumour suppressor protein, p53 in A549 cells while significantly downregulating anti-apoptotic proteins such as Bcl-2, Bcl-xL, XIAP, cIAP-2, survivin, and heat shock proteins (HSP27, HSP60, and HSP70). These findings suggest a reduced threshold for apoptosis and a potential promotion of apoptosis, possibly through p53 activation. Copper-imidazo[1,2-a]pyridines have demonstrated effectiveness in inducing apoptotic cell death in A549 cells, impacting both intrinsic and extrinsic apoptotic pathways and influencing critical proteins for cellular survival and apoptosis. This study contributes to a better comprehension of apoptotic mechanisms in A549 cells, stimulating inquiries into the activation of extrinsic apoptotic pathways especially by copper complexes. These findings support further pre-clinical evaluations of copper-imidazo[1,2-a]pyridines, including efficacy assessments in lung cancer animal models, toxicity studies, and determination of pharmacokinetic propertiesItem The wound healing effect of exosomes derived from Lobostemon fruticosus(University of the Witwatersrand, Johannesburg, 2024) Rajcoomar, Yashmika; Somandi, KhonzisizweExosomes are increasingly being researched and recognized as a novel mode of intercellular communication which can potentially play a significant role in many cellular processes, including immune responses, signal transductions and antigen presentation. Exosomes are membrane bound nanovesicles produced by both mammalian and plant cells. Developing research is mainly focused on their ability to act as a drug delivery vehicle. Other research interests around exosomes are their therapeutic effects for many common diseases including cancer and chronic inflammation. Plant-derived exosomes have emerged as potential candidates for many clinical and therapeutic applications. The aim of this project was to isolate exosomes derived from Lobostemon fruticosus leaves and to investigate the wound healing potential from this plant species. The plant-derived exosomes were isolated by ultracentrifugation and were characterised by means of scanning electron microscopy (SEM), ZetaSizer, Energy-dispersive Xray spectroscopy and the Pierce™ BCA Protein Assay Kit. The wound healing potential was assessed by In vitro scratch assay using human keratinocytes (HaCaT). The exosomes displayed a round, spherical shape and had diameters ranging from 41 to 67 nm – falling within range of nano-sized exosomes. The exosomes had a mean particle size of 166.2 d.nm. Chemical analysis of the samples using energy dispersive spectroscopy revealed the presence of carbon, oxygen, potassium, chloride, gold, palladium and sodium. The protein quantification results revealed the exosomes were rich in proteins. The cell viability results, using various concentrations of Lobostemon fruticosus exosomes, revealed non-cytotoxicity on HaCaT cells. The In vitro scratch assay demonstrated that the exosomes enhanced the migration ability of HaCaT cells in a time dependent manner. The findings suggest and reveal that exosomes derived from Lobostemon fruticosus could accelerate the healing process and can be employed as a future drug delivery platform. Further research is required to establish the exact mechanism of action of the healing potential of this plant specie's constituents. Overall results suggest that exosomes derived from Lobostemon fruticosus are promising as a potential agent for skin regenerationItem A Survey of the Delivery of Clinical Services in Independent Community Pharmacies in South Africa(University of the Witwatersrand, Johannesburg, 2024) Ismail, Tahir; Khan, RazeeyaIntroduction The community pharmacists' role has evolved from traditional medicine dispensing to patient- centred service provision. Community pharmacy clinical service provision is an integral component of public health intervention and contributes to universal health coverage. The extent of clinical services offered in community pharmacies in South Africa has yet to be studied. Assessing the extent of clinical service provision in community pharmacies provides insight into the willingness of South African pharmacists to deliver these services. Aim This study aimed to identify the clinical services offered in independent community pharmacies in South Africa and the extent to which these services are available. In addition, the willingness to provide clinical services and the barriers to service provision were also assessed. Methodology A quantitative, cross-sectional exploratory research design was used. Responsible pharmacists of the Independent Community Pharmacy Association member pharmacies were invited to participate in an anonymous electronic REDCap© survey from September 2022 to March 2023. Data was exported to Microsoft Excel® and analysed using descriptive statistics. Results Of the 156 responses received, most were located in urban areas (70%) and based in Gauteng (34.8%). The most frequently delivered clinical services were diabetes screening (88.9%), blood pressure measurement (80.8%) and Influenza vaccination (78.9%). Clinical services were primarily delivered by a pharmacist (39.5%), with most pharmacists (94.7%) willing to implement additional clinical services. However, lack of time and remunerations for services (57.1%) were identified as barriers to implementation. Most pharmacists also expressed an interest in additional training to improve clinical skills. Conclusion This study revealed the extent of clinical service delivery in independent community pharmacies in South Africa. Although community pharmacists are willing to provide clinical services, significant barriers limit these interventions. This study also informs service providers of training programmes that need to be developed to meet the specific needs of independent community pharmacists. Further research must address how the barriers identified may be mitigated to facilitate clinical service implementation in community pharmaciesItem Brain concentrations and the neurochemical effects of passively administered fluoxetine in Flinders sensitive line rat offspring(University of the Witwatersrand, Johannesburg, 2023) Steyn, Stephanus FrederikBackground: Globally, 36 % of women who have recently given birth, experience symptoms of depression and anxiety. Effective antidepressant treatments are limited, with fluoxetine being a popular treatment option. Fluoxetine is expressed in the breast milk, yet it is unclear to what extent fluoxetine, or its active metabolite, norfluoxetine, reaches the brain of the developing child and what the effects of such exposure on the related neurobiological processes would be. Due to ethical considerations and practical restrictions, clinical investigations into the neurodevelopmental effects of passively administered antidepressants (via the breast milk) are problematic. Therefore, pre-clinical investigations into this topic are not only important but clinically relevant. Aims & objectives: We aimed to quantify the concentration of passively administered, i.e., via the breast milk during nursing, fluoxetine, and its active metabolite, norfluoxetine in the whole brains of exposed Flinders sensitive line (FSL) rats (an established rodent model of depression). We further aimed to establish if said exposure would associate with changes in whole-brain serotonergic function and redox status. Methods: Adult FSL dams received fluoxetine (10 mg/kg/day), or placebo for fourteen days, beginning on postpartum day 04. Offspring (n = 16 per exposure group; 1:1 male: female) were passively exposed to fluoxetine until postnatal day 18 and euthanized on postnatal day 22. Whole brain fluoxetine, norfluoxetine, serotonin, 5-hydroxyindoleacetic acid (5-HIAA), and reduced and oxidized glutathione (GSH and GSSG) concentrations were measured via liquid chromatography/mass spectrometry (LC-MS). Results: Fluoxetine, was undetectable in the brain of FSL offspring, while norfluoxetine concentrations, averaged 41.28 ± 6.47 ng/g. Neither serotonin, nor its metabolite (5-HIAA), was affected by passively administered fluoxetine in the juvenile brain. In terms of redox status, pups exposed to fluoxetine presented with a compromised antioxidant defence, as evinced by a lower GSH/GSSG ratio. Discussion and conclusion: Although fluoxetine and norfluoxetine concentrations have been measured in breast milk and infant plasma, to the best of our knowledge, it has not been quantified in the juvenile brain until now. Our results are in line with clinical findings, suggesting the infant norfluoxetine/fluoxetine ratio to be elevated, probably because of the prolonged half-life of norfluoxetine. Although only norfluoxetine was detected, this did not influence the central serotonin concentrations of offspring. However, it associated with increased oxidative stress, of which the pathophysiological significance remains to be established. Taken together, our findings confirm that passively administered fluoxetine does reach the infant brain in the form of norfluoxetine and may manipulate processes of oxidative stress regulation. Further studies into the long-term bio-behavioural effects are however needed to effectively inform breast feeding mothers on the safety of antidepressant-use during the postpartum periodItem Essential oil compounds in combination with conventional antibiotics for dermatology(University of the Witwatersrand, Johannesburg, 2024) Simbu, Shivar Bram; Van Vuuren, SandySkin and soft tissue infections represent a heterogeneous array of clinical entities with varying severity, causative pathogens, and rates of progression. The slow development and overuse of antimicrobial agents have perpetuated the spread and severity of antimicrobial resistance. Natural products such as essential oils and their compounds are often investigated for their pharmacological properties, with particular interest in their antimicrobial properties. This study aimed to investigate the effects of combining six essential oil compounds (α-pinene, γ-terpinene, ±linalool, eugenol, carvacrol, and cinnamaldehyde) with eight conventional antimicrobials (amoxicillin, ciprofloxacin, erythromycin, gentamicin, meropenem, tetracycline, miconazole, and nystatin) against six commonly encountered skin pathogens (Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228, Pseudomonas aeruginosa ATCC 27853, Acinetobacter baumannii ATCC 19606, Cutibacterium acnes ATCC 11827, and Candida albicans ATCC 10231) to elucidate the interactive profiles, toxicity, and anti-inflammatory properties. The antimicrobial analysis involved determining the minimum inhibitory concentrations (MIC) of the conventional antimicrobials and essential oil compounds, singularly and in combination, using the broth microdilution assay. The sum of the fractional inhibitory concentrations (ΣFICs) was calculated to investigate the interactive profile of the combinations. Synergistic interactions were further analysed at varying ratios and depicted on isobolograms. Eight synergistic interactions were identified, with seven against Gram-positive bacteria (ΣFIC 0.07– 0.42) and one against P. aeruginosa (ΣFIC 0.32). In addition, it was demonstrated that when in combination, the selected combinations resulted in reduced toxicity (Brine-shrimp lethality assay). The combination of amoxicillin and eugenol demonstrated the lowest toxicity (LC50 = 1081 μg/mL) and the highest selectivity index (14.41) when in a (70:30) ratio with the antibiotic in the higher ratio. Based on the synergistic results from the antimicrobial analysis, a selection of essential oil compounds with conventional antimicrobials were assessed for cytotoxicity and anti- inflammatory properties. The cytotoxicity properties were determined using the MTT assay on HaCAT keratinocytes. The anti-inflammatory properties were determined using lipopolysaccharide (LPS) activated RAW 264.7 macrophages, and the reduction in nitrate (NO) production was measured. Cinnamaldehyde demonstrated the highest cytotoxicity (IC50 = 28.63 μg/mL, p < 0.05) and the greatest reduction (77.44%) in nitrite production, which was also concentration dependent. The combination of ciprofloxacin and cinnamaldehyde demonstrated the lowest cytotoxicity (88.42% ± 3.72 cell viability; combination index of 0.12) and the highest reduction in nitrite production (77.42%; ΣFa = 0.44). Further investigations on the interactive properties of ibuprofen were undertaken. The antimicrobial, cytotoxicity, and anti-inflammatory properties of ibuprofen were analysed singularly and in combination with all essential oil compounds and conventional antimicrobials against reference and clinical skin pathogens. For the MIC results, four synergistic interactions were identified between ibuprofen and conventional antimicrobials (ΣFIC 0.33 - 0.50). For the cytotoxicity (MTT assay), none of the combinations demonstrated a cytotoxic effect (cell viability of 93.6-100%) and significant reduction on nitric oxide production. Additionally, higher order combinations involving the synergistic combinations were investigated with the inclusion of the essential oil compounds. Three synergistic interactions were identified (One against C. acnes and two against A. baumannii). The triple combinations were slightly cytotoxic (cell viability of 77.59 - 90.44%; combination index of 0.95 -1.10) on the HaCAT cell line and did not reduce nitric oxide production. Based on the overall results from this study, combinations of essential oil compounds and some conventional antimicrobials demonstrate promising therapeutic approaches to attenuate antimicrobial resistance. These results demonstrated that combinations that comprise cinnamaldehyde have noteworthy antimicrobial and anti-inflammatory properties which may warrant further investigation. Combining ibuprofen with conventional antimicrobials and essential oil compounds may also offer potential advantages in managing resistant infections through direct and indirect antimicrobial mechanisms.Item A retrospective review on the utilisation of meropenem in a tertiary hospital setting(University of the Witwatersrand, Johannesburg, 2024) Mohun, ShameedaIntroduction: The discovery of antibiotics is widely regarded as a groundbreaking accomplishment in the medical industry, as it has facilitated the elimination of countless diseases. Nonetheless, the overuse and reckless consumption of these medicines have led to a global upsurge in antibiotic resistance, particularly in broad-spectrum antibiotics such as meropenem, which are often prescribed for severe infections. Aim: The aim was, therefore, to assess the utilisation trends of meropenem in treating patients at a tertiary hospital located in the North-West Province of South Africa. Methodology: This study involved a retrospective review of hospital records at a 396-bed tertiary hospital in the public sector of South Africa, for patients who were prescribed meropenem between January and December 2021. A total of 218 patient files were included in the analysis after removing the duplicates and incomplete files. Variables investigated were patient demographics, prescribing criteria, diagnosis, treatment indication, microorganisms, and sensitivity cultures, as well as the appropriateness of prescribing. Descriptive statistics were employed to analyse the data. Results: Meropenem was primarily used empirically in adult patients (65.1%), while clinicians treating paediatric patients generally reserved its use for definitive cases (55.1%). Recording of the source of infection was poor with 72.1% of adults and 96.6% of paediatrics lacking such documentation. Although all prescriptions analysed were deemed valid, only a small percentage of treatments were considered appropriate (3.1% in adults). The study also revealed that clinicians frequently ordered microbiological cultures and blood sensitivity tests prior to administering antibiotics, at rates of 50.4% in adults and 71.9% in paediatrics. Notably, the most cultured bacteria were Klebsiella pneumoniae (25.2%) in paediatric patients and Acinetobacter species (25.0%) in adults. Conclusion: The study's results reveal a clear contrast between suggested protocols and clinical practices in the real world, stressing the pressing need for effective antimicrobial strategies to counter the growing threat of meropenem resistance. Several areas of concern were identified, including non-adherence to guidelines, insufficient step-down therapy, and incomplete documentation. Despite being a broad-spectrum antibiotic intended for definitive diagnoses, meropenem is often prescribed empirically, further highlighting the need for continuous medical education, practical therapeutic committees, and frequent drug utilisation evaluations to tackle this issueItem The development of a questionnaire to assess training and match demand in adolescent cricketers(University of the Witwatersrand, Johannesburg, 2024) Grobler, Nico; Olivier, BenitaBackground: Recording training and match demand in adolescent sports is essential in preventing overtraining and injuries while ensuring optimal performance and well-being. The study aimed to develop a valid and reliable questionnaire that would measure the training and match the demands of adolescent cricketers. Methods: In Study 1, the content validity of the training and match demand questionnaire was measured using the content validity index, while the reliability was measured using Kendall’s coefficient of concordance (Kendall’ W). In Study 2, a pilot study was performed using the questionnaire developed in Study 1. Daily training and match demand for all activities done in cricket (i.e., bowling, batting, fielding, strength and conditioning) and any other sport or activities were recorded in 17 adolescent cricketers. Acute:Chronic workload ratios (ACWR) were determined for all activities. Results: The developed questionnaire was deemed valid (I-CVI score of 0.83) and reliable (Kendall’s W score of 0.63). Over the 7-week period, some spikes in the acute training and match demand were observed. However, the overall ACWR was within the norms (0.8-1.3). Bowling reported an average ACWR of 0.91; other sports reported the highest average of 1.08, while the average for all activities combined was 0.92. Conclusion: The questionnaire measured the training and match demand of the cricketer over time and can be used as a valuable tool in future research and practice in adolescent cricket