3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item Skin, trace and material process in selected works by Leora Farber(2011-08-23) Burton, Maria Teresa MacedoItem Molecular characterisation of the extracellular matrix protein 1 gene in lipoid proteinosis in South Africa(2006-11-20T10:15:41Z) van Hougenhouck-Tulleken, George; WesleyLipoid proteinosis (LP) (OMIM 247100) is a rare autosomal recessive disorder that is caused by mutations within the extracellular matrix protein 1 gene (ECM1). The ECM1 gene has been shown to play a role in angiogenesis and connective tissue matrix generation, especially in skin and bone. The role of ECM1 in normal skin development and maintenance is further highlighted by its role in LP and in lichen sclerosis where autoantibodies are raised against ECM1. LP usually presents in the first year of life with a faint or hoarse cry and is due to a hyaline-like material deposited in the mucous membranes of the vocal cords. Gradually (over years) there is diffuse skin infiltration and general skin thickening with a yellow, waxy appearance. There is excessive scarring with scars often appearing at sites of minor injury or stress. In many cases, the eyelids show typical beaded papules. In some cases, calcification of certain aspects of the temporal lobes have been observed, and may or may not be associated with variable neurological, psychiatric and neuropsychological sequelae. Although the prevalence of LP in South Africa is unknown, the disproportionately high number of case reports originating from South Africa indicates that LP is unusually common in certain South African populations, most notably the Coloured population of Namaqualand and the Afrikaans-speaking White population. This may be due to a possible LP founder effect that occurred early during the European colonisation of South Africa. The founder effect was investigated in the South African LP patients by conducting ECM1 mutation and linked marker analysis. The data supported a LP founder effect as the Q276X mutation in exon seven of ECM1 was present in the homozygous state in all LP patients investigated. In addition, the Q276X mutation was associated with a single founder haplotype of 19-12-23-22 (ND1-D1S2343-D1S305-D1S2624). These markers were in significant linkage disequilibrium with each other and with the Q276X mutation. VI As variation within ECM1 may alter properties of skin such as healing and scar formation, ECM1 exons two through five and the first part of exon six were investigated for nucleotide variation using denaturing high performance liquid chromatography (dHPLC) and direct DNA sequencing in three different South African populations. Eight nucleotide variants were identified, of which six were cytosine to thymine transitions. Seven of the eight variants identified were either intronic or synonymous, with one variant being a missense variant, changing a methionine residue to a threonine residue (T130M).Item In vitro 5-lipoxygenase and anti-oxidant activities of South African medicinal plants commonly used topically for skin diseases(2006-11-14T10:27:22Z) Frum, YakovABSTRACT Thirty plant species traditionally used to treat skin pathologies were chosen from the readily available ethnobotanical literature. Four plants (aqueous or methanol extracts) displayed promising 5-lipoxygenase inhibitory activity with IC50 values below 61 ppm. These included Aloe greatheadii, Melianthus comosus, Pentanisia prunelloides and Warburgia solutaris. Essential oils generally displayed superior 5- lipoxygenase inhibitory activity with IC50 values between 22 and 75 ppm. These included the essential oils of Ballota africana, Helichrysum odoratissimum, Heteropyxis natalensis and Lippia javanica. A large proportion of the plants exhibited dose-dependent DPPH anti-oxidant activity with IC50 values between 5 and 94 ppm for the most active. These included Halleria lucida, Croton sylvaticus, Melianthus comosus, Lippia javanica and Pentanisia prunelloides. Aqueous extracts of Melianthus comosus exhibited the most potent anti-inflammatory and anti-oxidant activity. The methanol extract of the leaves of Halleria lucida was subjected to activity guided fractionation and two anti-oxidant molecules were isolated, namely luteolin-5-Oglucoside and verbascoside (acteoside). Isobologram construction resulted in a concentration-dependent additive and antagonistic interaction being recognised between the two isolated compounds. Warburgia salutaris displayed promising 5-lipoxygenase inhibitory activity. Two isolated compounds, mukadiaal and warburganal were found to partially contribute to the anti-inflammatory activity of the plant. The essential oils of Helichrysum odoratissimum, Heteropyxis natalensis and Lippia javanica were subjected to gas chromatography and major compounds contributing to possible anti-inflammatory effects identified. These included β-caryophyllene, 1,8-cineole, limonene and α- humulene. Enantiomers and racemic mixtures of limonene displayed significantly different 5-lipoxygenase inhibitory activity suggesting stereoselectivity of the enzyme-catalysed reaction. The monoterpene 1,8-cineole appeared to cause partial potentiation of the anti-inflammatory activity displayed by limonene. These results provide some in vitro scientific rationale for their traditional use as dermatological agents.