Faculty of Health and Environmental Sciences ETDs
http://hdl.handle.net/11462/11
2024-03-28T14:43:59Z
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An Investigation Into The Phytochemistry And Biological Activity Of Pappea Capensis Used Against Cancer
http://hdl.handle.net/11462/2510
An Investigation Into The Phytochemistry And Biological Activity Of Pappea Capensis Used Against Cancer
Makhoahle, Pakiso, Moses
ascertain the medical benefits and safety of the woody part of this plant.
The sensitivity testing of the plants plays a critical role in ascertaining the safety use of the plant extracts. In this study, antimicrobial screening showed that different extraction methods isolated the active compound which the solvent type depended on. The ethanoic and methanolic extracts were showed to have active compounds against Gram positive and Gram-negative organisms. Both extracts (ethanoic and methanolic) indicated that potential antimicrobial compounds were in the high polarity fraction. Water was found to be the only solvent mostly used by Sangomas and traditional healers to make medicinal mixtures for their patients. Then antimicrobial activity was extended by including other organisms. The Staphylococcus aureus and Klebsiella pneumoniae were found to be susceptible to ethanoic and methanolic extracts. However, in chapter 5 methanolic extract showed broad antimicrobial activity against two organisms known as part of the normal flora (Staphylococcus epidermidis and Enterococcus faecalis) which are both Gram positives. The water extract showed antimicrobial activity against Klebsiella pneumoniae, although no antimicrobial activity was observed against all Gram-positive organism. The Pappea capensis plants extract were screened for cytotoxity against the three cell lines (vero cells, MCF7 and PC). Upon comparing the used control and the only extract showing slight toxicity, it’s conclusive to say the high dose of methanolic extract is physiologically inappropriate. All extracts that are not active (cytotoxic) enough to suggest Pappea capensis can be taken into further anticancer testing. The extracts were further screened for genotoxicity. Two extracts were considered none genotoxic and the ethanoic extract could be considered genotoxic. The micronucleated cells of 30% were determined at the high concentration (200ug/ml) of ethanoic extract. A further test should be done to predict what mechanism is affected by compounds in ethanoic extract. The results indicate the potential use of this plant against cancer, despite the moderate genotoxicity at 200ug/ml.
The in vitro screening results for anti- and pro-inflammatory assays are shown in fig 8.1 (A and B) for the analysis of NO production and the cell viability analysis on LPS-activated macrophages treated with the different extracts concentrations. There was an increased NO production which correlated with each extract cytotoxicity in LPS- activated macrophages (fig 8.1 B). Resveratrol, a known inhibitor of iNOS expression served as a positive control to the regime. In fig 8.2 there was macrophage activation observed which was extracts concentrations depended. This response to treatment with different concentrations of Pappea capensis extracts corresponded with NO production in fig 8.2 and a similar trend was observed with the analysis of cell viability (fig 8.2 A and B) which predicts the corresponding cytotoxicity of all extracts. However, there was a high NO production and observable macrophage activation in the presence of water extract no. 7 (fig 8.2). A confirmatory test was done to ascertain if this effect is owed to plant constituents or due to endotoxin contamination. Then, NO production was analysed in the presence and absence of polymyxin B (PMB) as shown in fig 8.3. It can be concluded that PMB counteracts the pro-inflammatory effect suggesting that this activity is possibly a result of endotoxins in this part of the plant. The determination of endotoxin as a cofactor perpetrating pro-inflammatory activity tested with polymyxin B was used and indicated the presence of a toxin in water extract. The low anti-inflammatory effect seen in the three extracts at 200ug/ml are not physiologically active.
The GC-MS revealed the presence of 41 compounds which included 4-ethylbenzaldehyde, 2, 4-di-ter-butyl phenol, acetic acid and butanoic acid have the role in antioxidant, antimicrobial, antitumor, antifungal effects. The identified alkanes and aldehydes are possible poisonous compounds identified in fig 8.2A. Then it can be concluded the pro-inflammatory activity was indeed caused by toxin or poisonous compounds from the plant itself. Furthermore, seven (7) unknown bioactive chemical compounds were revealed regardless of their amounts, their existence could be having a positive impact on therapeutic agents and a source of the biological activities claimed for between traditional healers. Furthermore, many diverse chemical compounds identified and some quantified make it a holistic plant for use in traditional medicine and for aesthetic value between the local communities in Limpopo. More scientific tests are needed to carry out bioassay guided fractionation of the three extracts to determine the purified compounds and identify the ones that are biologically active.
Medicinal plants, being the only sources that healers and Sangomas rely on for treatment of their patients have received tremendous attention in drug therapy, discovery and development. In conclusion, this study has shown that the Pappea capensis may serve as a new possible source of remedies due to the presence of these phytochemicals, bioactive compounds and antimicrobial activities.
Dissertation
2019-11-03T00:00:00Z
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The Prevalence Of Antibiotic-Resistant Bacteria In Street-Vended Foods
http://hdl.handle.net/11462/2508
The Prevalence Of Antibiotic-Resistant Bacteria In Street-Vended Foods
Moloi, Malerato
In recent years, the street-food vending industry has expanded globally, especially in developing countries and the expansion continues (Bereda et al., 2016). This industry has played a significant role in the socioeconomic development of these countries. In addition, it has a positive impact on urban dwellers as the majority of them depend on these foods for convenience (Bereda et al., 2016). Despite the economic benefits of street foods, there is a need to reflect on the hazards imposed by foods prepared within the food-vending industry. These foods may play a role in the transmission of disease-causineg microbes within a population (Ogidi et al., 2016) that may exhibit antibiotic resistant profiles.
Several studies have been carried out in South Africa to establish the relationship between food handling and the occurrence of food contaminants. However, few studies have been conducted in the Free State, therefore this area formed the basis of this study. This study had three aims, the first of which was to assess hygienic practices of the street food vendors and secondly, to evaluate factors that contributed to contamination and isolated microbes from surfaces and foods. This was followed by an assessment of the susceptibility of isolated microbes towards antibiotics. The study was carried out in Mangaung Metropolitan Municipality. In the current study, the data on the hygiene practices and potential risk factors was collected using questionnaires and an observation checklist. The results obtained indicated that even though the vendors had a positive attitude towards food safety, non-compliance with food safety regulations was observed. Some of the vendors did not wash their hands and did not wear aprons during the processing and serving of food. Moreover, the vendors reported that they had not received any training in food safety and hygiene. It was also observed that the material used for the construction of the stalls was not able to protect the food from dust, given that all the stalls were situated by the roadsides, which were dusty and prone to fumes from motor vehicles. Furthermore, a lack of sanitation facilities was also a major problem identified.
Total viable counts were recorded on food preparation surfaces at various vending stalls in Thaba Nchu, Bloemfontein and Botshabelo. Microbial counts obtained in Botshabelo (1.1x104 to 1.1 x106 CFU/m2) showed higher microbial counts as compared to those in Bloemfontein (1.1x104 to 1.1 x105 CFU/m2) and Thaba Nchu (1.1x104 to 1.1 x105 CFU/m2). These counts were found to be higher than the national standard (100 CFU/m2). Other than food preparation surfaces, microbial counts of meat samples obtained in Bloemfontein, Thaba Nchu and Botshabelo were also found to be lower than the national standard (100 CFU/g). Nevertheless, the results showed the presence of S. aureus and E. coli indicates poor hygiene. This indicates that improper food handling practices were somehow carried out by food handlers, thereby contributing to the presence of these foodborne pathogens. The predominant species identified were S. aureus and E. coli. The presence of these species is a major cause of concern because S. aureus and E. coli are the most common bacteria that play a significant role in human diseases (Setlhare, 2013).
In addition, when antimicrobial susceptibility testing was performed, S. aureus isolates showed resistance to gentamycin (100%), streptomycin (63%) and tetracycline (68%) which would make the treatment of infections with this species difficult. Moreover, 62% of Shigella spp. showed resistance to ampicillin, followed by Escherichia hermannii which showed 50% resistance to ampicillin. Lastly, E. coli showed 100% resistance to ampicillin. This indicates that ampicillin will no longer be useful for treatment of any infection caused by Shigella, E. hermannii and E. coli. As these bacteria have developed resistance against the tested antibiotics, food contamination with antibiotic-resistant bacteria can also be a major threat to public health, because antibiotic resistance determinants can be transferred to other pathogenic bacteria potentially compromising the treatment of several bacterial infections (Eromo et al., 2016) within a population. Results from this study also indicate that the general public can easily be exposed to antibiotic-resistant bacteria daily through conventional food intake because the street vendors are non-complaint with food safety hygiene practices. Exposure of consumers to antibiotic-resistant bacteria may make them vulnerable to various food diseases caused by antibiotic-resistant pathogens.
Dissertation
2019-01-01T00:00:00Z
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Vegetation Cover Dynamics And The Environmental Threats To Biodiversity Conservation In Free State National Botanical Garden, South Africa
http://hdl.handle.net/11462/2503
Vegetation Cover Dynamics And The Environmental Threats To Biodiversity Conservation In Free State National Botanical Garden, South Africa
Vukeya, Loyd Rodney
The conservation gardens under South African Biodiversity Institute (SANBI) preserve biodiversity areas with unique and threatened vegetation types including national priority Critical Biodiversity Areas (CBA’s). The mandate of SANBI is to champion the exploration, conservation, appreciation, and enjoyment of South Africa’s exceptionally rich biodiversity for all people. Since the SANBI mandate emphasises sustainable biodiversity conservation, however, there were no studies that have quantitatively appraised the biodiversity conservation value and natural phenomena dynamics over time for different SANBI conservation gardens. This study determined the dynamics of the vegetation cover over a 30-year period (1987-2017) and potential environmental drivers of change in Free State National Botanical Garden (FSNBG). The FSNBG is located in the broader southern African grassland biome that is under huge conservation threats in South Africa. The FSNBG preserved national priority for biodiversity conservation (CBA1) in South Africa: the “Bloemfontein Karroid Shrubland”. The study applied the remote sensing technology and Geographical Information System (GIS) imagery to analyse the spatial vegetation cover changes that occurred over 30-years using 10 year’s intervals.
Overall study results show that vegetation cover of the study area significantly increased (in term of woody biomass) over the 30 year period, partly attributed to the combination of factors, which include severe droughts and the rise of CO2 concentrations in the atmosphere. In addition, it was possible that absence of the biophysical disturbance such as fire and browsers in the natural vegetation to suppressed wood species has encourage encroachment of woody cover species. Using Normalized Difference Vegetation Index (NDVI) approach, the vegetation of FNSBG was divided into four categories, namely: Dense vegetation, Moderate vegetation, Sparse vegetation and open soil. Overall, the sparse vegetation cover significantly decreased over time (R2 = - 0.29). Similarly, the moderate vegetation cover increased by 25.1 ha while dense vegetation also increased by 8.6 ha. However, the bare soil cover was found to be relatively consistent over the 30-year period.
Since the use of the remote sensing and GIS imagery could not clearly validate the current ecological status of CBA1 vegetation type, the manual field sampling approach was used looking into documenting the typical plant species provided by Mucina and Rutherford (2006); and measuring the vegetation cover. Vegetation cover of CBA1 was relatively high (i.e., 79.6 ± 15.9%); and this was above the minimum threshold of 60% habitat intactness reported to represent the habitat functionality that is normal although overall integrity is reduced. The existence of CBA1 vegetation type was supported by a record of 27 plant species out of 77 species documented as typical in the key descriptions provided by Mucina and Rutherford (2006). Major conservation threats entailed of 27 invasive alien plant species, human settlement encroachment have reduced the ecological buffer zone of FSNBG by 18% (119.07 ha) in the past 18 year; and 10 pests and pathogens that were interspersed in different vegetation patches of the study site. The observed changes suggested a need for regular vegetation monitoring of CBA1 vegetation type to manage the prevailing conservation threats that could have impact to ecological integrity.
Animal-plant mutualisms are important for the maintenance of both animal and plant population since both participating partners’ benefit. The phenology of seed dispersal is critical to the successful recruitment of species since dispersed seeds require conducive conditions for germination. Having noted the increasing bush encroachment in FSNBG in the past 30 years, the study also investigated the seed dispersal phenology and the potential influencing factors for the encroaching tree/shrub species of FSNBG focusing on biotic interaction of flesh fruits resource foraged by birds as study model. During fieldwork sampling for the seed deposited by birds in the 17 roosting sites, I collected a total of 22 161 seeds belonging to 14 native and non-native tree/shrub species. It was found that black and red fruits were more preferred by birds since most of the dispersed tree/shrub species had those colours and attracted 22 resident and colonial migratory frugivorous birds. I found that 80% of the bird-ingested and dispersed seeds of many tree/shrub species were collected between March and July. Two species: Ehreta rigida and Searsia lancea, displayed relatively short fruiting peak times between August and December when other fruits were scarce. Whereas the observed two fruiting patterns could reduce the competition for seed dispersal services between two groups of tree/shrub species, the resident and wintering birds are also likely to benefit substance in food resources. In addition, it was found that frugivorous birds adapt to localised foraging patterns and to limited fruit diversity. It was concluded that the highly preferred tree/shrub species are likely drivers of the reported bush encroachment in FSNBG.
Frugivorous birds disperse seed away from parent plant to new microsites that have relatively lower competition for the resources, and ingested seeds get scarified during feeding on fruits and ingestion by birds. Therefore, the study also investigated whether bird-dispersed seeds benefit from improved germination after their passage through the bird’s gut and the potential impact of seed density on competition at the microsites. On the germination trail results of bird-ingested seeds versus manual depulped seeds, Ziziphus mucronata displayed the highest germination rate of all trees/shrubs yet frugivorous birds did not improve its seed germination. However, only S. lancea seeds had significantly high seed germination after passage through the avian digestive tract. The test experiments for seed competition during germination at the microsite showed that only Z. mucronata and Olea europaea subsp. africana displayed significant positive performance with increasing seed density. The study concluded that the tree/shrubs species with high germination could account for the observed bush encroachment in FSNBG. It was recommended that adaptive conservation management plan of FSNBG should include monitoring and prioritised bush encroachment control of those species.
Thesis
2021-01-01T00:00:00Z
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Radiation Dose And Image Quality From Pelvic Localisation Computed Tomography In Oncology
http://hdl.handle.net/11462/2388
Radiation Dose And Image Quality From Pelvic Localisation Computed Tomography In Oncology
Verreynne, V.C.
Introduction: Computed tomography (CT) in radiation therapy plays an important role in the accurate identification of the position of the tumour and organs at risk, through high geometric fidelity of the CT image. It has been determined that the radiation dose from CT is amongst the highest from all medical imaging. There is concern over the increased radiation dose from pelvic CT localisation scans, due to the increased scan length and the necessity for high image quality used in radiation therapy planning. The necessity for high image quality, while lowering the CT dose and honouring the ALARA principles, is essential.
Four article-style studies, which evaluate the CT dose and image quality produced for pelvic localisation scans and that are ultimately aimed at publication, are presented in this research paper.
Purpose: The purpose of this research was to determine the CT dose and image quality produced for pelvic localisation scans in a department of oncology, Free State. The aim was to measure the dose received by patients during pelvic CT localisation scans and to determine whether the dose is justified in terms of imaging requirements for radiation therapy planning. The objectives of the research were to (i) determine baseline dose level for pelvic CT scan utilising an anthropomorphic phantom, (ii) measure patients’ CT pelvic localisation dose by using size-specific dose estimates, (iii) to verify whether the field of view (FOV) modified image quality for patients of different sizes, utilising water phantoms and (iv) objectively examine image quality using the contrast-to-noise ratio (CNR) for patients’ CT localisation scans. The significance of this research is reflected in filling the gap in existing literature, as most published studies were conducted on diagnostic CT dose and image quality.
Methodology: The research was conducted as a prospective research study, performed between January and June 2019, after ethical approval was obtained. All CT scans were produced on a TSX-201A (Toshiba Aquilion © Large Bore) CT scanner. The CT baseline dose level was established utilising an anthropomorphic phantom. The patient dose for pelvic CT localisation was calculated by the size-specific dose estimate (SSDE) that determines the dose, based on individual patient dimensions. The participants were divided into three body mass index (BMI) categories; these were underweight, normal weight and overweight. The CT image quality was examined based on scans of different sized water phantoms utilising CT quality assurance tests. The patients’ CT image quality was derived from the contrast-to-noise ratio (CNR). Results: A total of 131 participants met the inclusion criteria of the research study and were grouped according to their BMI into categories, these being categorised as: overweight-, normal- and underweight BMI category. For the baseline dose level, the best kV and FOV combination was determined for the 120 kV setting with a large (L), large-large (LL) or extra-large (XL) FOV, which calculated at 14.0 cGy using SSDE. In terms of the BMI patient category the median dose was determined as: 12.3 cGy for an overweight BMI; 14.8 cGy for a normal BMI, which is in line with the baseline CT dose and 17.1 cGy for the underweight BMI category.
The image quality determined as per phantom indicated that the 135 kV demonstrated the highest quality as well as the highest dose. In terms of FOV the small and medium sized phantom could be scanned with any size FOV. However, the large phantom excelled with the L, LL and XL FOV. The results for the patients in terms of image quality, based on CNR illustrated that the normal BMI category patients had the highest quality. It was furthermore concluded that the overweight BMI patient category reflected the lowest image quality.
Conclusion: The research questions were addressed and the objectives of this research were indeed met. In addition, this research addressed the gap in relevant literature, by determining results based on oncological CT scans and protocols in terms of dose and image quality. The fact that only one anthropomorphic phantom was available for dose calculations and that no tissue types were present in the phantom to utilise for the image quality, limited the research. The researcher recommends that protocols for patients in different BMI categories be established for CT pelvic localisation scans whilst simultaneously adhering to the ALARA principles. Research demonstrates that there is an industrial drive to decrease dose while maintaining image quality. Numerous techniques have been introduced to assist with the reduction of dose. One of these techniques was illustrated by Irish researchers who established national diagnostic reference levels (DRL’s) for breast CT protocols in oncology. It is believed that by utilising knowledge from both diagnostic and oncology CT scan techniques, the reduction of CT dose - while maintaining image quality - is an achievable goal.
Dissertation
2020-01-01T00:00:00Z