Thesis (Ph. D.)--University of Hong Kong, 1998. / Includes bibliographical references (leaves 212-259).

Thesis (M.S.)--Rochester Institute of Technology, 1995. / Typescript. Bibliography: leaves 67-68.

Thesis (M.Med.Sc.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 65-72). Also available in print.

Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliographical references.

Exposure to organophosphorus pesticides (OPs), including malathion, is associated with the pathophysiology of neurological diseases, such as Autistic Spectrum Disorder (ASD). ASD is a neuropsychiatric disorder manifested by qualitative impairments in reciprocal social interaction, associated with motor disorders such as stereotypies and restricted interest. Due to the increased prevalence of ASD based on studies suggesting the contribution of OP to the pathophysiology of this disorder, it was aimed to evaluate the ontogenetic and behavioral effects of pre and postnatal exposure to malathion in Wistar rats. Pregnant females were divided into two groups: prenatal, received malathion (200mg / kg) per gavage on gestational days (DG) 06-14 and those receiving malathion during the lactation period (21 days). The control groups received vehicle in the period and volume equivalent. During the first 21 postnatal days, the offspring prenatally exposed to malathion were submitted to the analysis of ontogenetic and reflexological parameters. Sexing occurred shortly after the analysis of reflex ontogenesis. In postnatal day (PND) 30, 45 and 60, males exposed in both the pre- and postnatal periods were submitted to behavioral and cognitive parameters analyzes. The results showed that prenatal exposure to malathion caused significant behavioral changes characterized by hyperactivity, increased stereotyped movements and social impairment, as well as cognitive impairment related to animal memory. There were no changes in the physical development of the offspring exposed to malathion in relation to the control group, suggesting that the damage caused by the early exposure to malathion is exclusively neurological. The behavioral parameters affected by prenatal exposure to malathion also became impaired after postnatal exposure. The changes observed in this study are compatible with the symptomatology of patients with ASD. The understanding of these effects alerts to the use of this compound due to its neurotoxic potential and reinforces the environmental contribution of OP in the pathophysiology of neurological diseases, such as ASD. / Submitted by Fabiane dos Santos (fabiane.santos3@unisul.br) on 2017-10-09T18:56:04Z No. of bitstreams: 2 Dissertação Ciências da Saúde- Diego Anacleto Souza.pdf: 1598366 bytes, checksum: f866caa8076cdcd6a95b82520a97747f (MD5) Termo de Cessão de Direitos Autorais- Diego Anacleto de Souza.pdf: 774408 bytes, checksum: 96cda76f2bd01b9baeb1365f502815f7 (MD5) / Approved for entry into archive by Ana Barreiros (ana.barreiros@unisul.br) on 2017-10-09T18:58:10Z (GMT) No. of bitstreams: 2 Dissertação Ciências da Saúde- Diego Anacleto Souza.pdf: 1598366 bytes, checksum: f866caa8076cdcd6a95b82520a97747f (MD5) Termo de Cessão de Direitos Autorais- Diego Anacleto de Souza.pdf: 774408 bytes, checksum: 96cda76f2bd01b9baeb1365f502815f7 (MD5) / Made available in DSpace on 2017-10-09T18:58:10Z (GMT). No. of bitstreams: 2 Dissertação Ciências da Saúde- Diego Anacleto Souza.pdf: 1598366 bytes, checksum: f866caa8076cdcd6a95b82520a97747f (MD5) Termo de Cessão de Direitos Autorais- Diego Anacleto de Souza.pdf: 774408 bytes, checksum: 96cda76f2bd01b9baeb1365f502815f7 (MD5) Previous issue date: 2017 / A exposição aos agrotóxicos organofosforados (OFs), incluindo o malathion, vem sendo associado a gênese de doenças neurológicas, como o Transtorno do Espectro Autista (TEA). O TEA é um distúrbio neuropsiquiátrico manifestado por prejuízos qualitativos na interação social recíproca, associado a distúrbios motores como estereotipias e interesse restrito. Devido ao aumento da prevalência do TEA e baseado em estudos que sugerem a contribuição de OF na origem deste transtorno, objetivou-se avaliar os efeitos ontogenéticos e comportamentais da exposição pré e pós-natal ao malathion em ratos Wistar. Para tanto, fêmeas prenhes foram divididas em dois grupos: Pré-natal, receberam malathion (200mg/kg) por gavagem nos dias gestacionais (DG) 06-14 e as que receberam malathion ao longo do período de lactação (21 dias). Os grupos controle receberam veículo no período e volume equivalente. Ao longo dos primeiros 21 dias pós-natais, a prole exposta pre-natalmente a malathion foi submetida a análise de parâmetros ontogenéticos e reflexológicos. A sexagem ocorreu logo após término da análise da ontogênese de reflexo. No dia pós-natal (PDN) 30, 45 e 60, os machos expostos tanto no período pré quanto pós-natal foram submetidos a análises de parâmetros comportamentais e cognitivos. Os resultados mostraram que a exposição pré-natal ao malathion causou alterações comportamentais significativas caracterizadas pela hiperatividade, aumento de movimentos estereotipados e prejuízo social, bem como prejuízos cognitivos relacionados à memória dos animais. Não houve alterações no crescimento físico das proles expostas ao malathion em relação ao grupo controle, sugerindo que o dano provocado pela exposição precoce a malathion seja exclusivamente neurológico. Os parâmetros comportamentais afetados pela exposição pré-natal a malathion também se tornaram prejudicados após exposição pós-natal. As alterações observadas neste estudo são compatíveis com a sintomatologia de pacientes com TEA. A compreensão destes efeitos alerta para o uso deste composto devido ao seu potencial neurotóxico e reforça a contribuição ambiental de OF na fisiopatologia de doenças neurológicas, como o TEA.

Magister Scientiae Dentium - MSc(Dent) / Despite the phenomenal strides in research of dental resin composites regarding their physical and mechanical properties, discolouration, either intrinsic or extrinsic still remains a major drawback and is one of the main reasons for the replacement of these restorations. Toothbrushing and polishing procedures have been attempted to eliminate extrinsic staining without optimal results. Vital tooth bleaching has over 90% success rates in whitening discoloured teeth and this may be an alternative treatment modality for discoloured composite resins. Aim: The aim of this study was to determine whether tooth bleaching agents alter the colour of stained direct composite resins. Material and Method: 60 disc shaped specimens (9 x 2mm) of Filtek Supreme XT were prepared. They were randomly divided into 3 groups (n = 20) and exposed to either one of two experimental staining agents, tea or red wine, or artificial saliva (control) continuously over a 7-day period. They were all then bleached with Opalescence Xtra Boost, a chemically activated in-office whitening agent for 3, weekly sessions of a half hour each, broken into 2, fifteen minute cycles. Colour determinations were made using a reflectance spectrophotometer, from baseline, after each day of staining, after the bleaching treatments and after a 1 week rehydration period. The CIE Lab colour space was used and colour changes were monitored using ΔE, that was calculated during intervals between the experimental episodes using L, a and b values. A ΔE ≥ 3.3 represented colour changes that were deemed clinically noticeable. Data analysis was carried out using Microsoft excel and a non-parametric test (Wilcoxon Signed Sum Rank Test) with a significance level set at ≤ 0.05 for colour differences that are statistically significant. Results: Both staining solutions discoloured the composite resin samples, but red wine produced greater colour changes than tea. After bleaching, the specimens in the tea group reverted to baseline colour with a ΔE ≤ 3.3 but those in the red wine group did not revert to baseline values with a ΔE ≥ 3.3. Conclusion: Filtek Supreme XT, a nanocomposite, is susceptible to discolouration by chromogenic beverages. Red wine produced deeper staining than tea. Opalescence Xtra Boost was effective in removing tea stains but not red wine stains. / South Africa

Thesis (MSc) -- University of Stellenbosch, 2005. / ENGLISH ABSTRACT: The Rooibos tea plant (Aspalathus linearis) is indigenous to South Africa and occurs only in the Western Cape's Cedarberg region. Rooibos tea is produced from the leaves and fine stems of the plant. The tea is normally prepared by brewing the leaves and consuming the liquor. However, the Rooibos plant is not only used to prepare tea; the plant extracts are also used in various neutraceutical and pharmaceutical products, including health drinks, iced tea, soaps and moisturising creams. Although the tea plant contains native enzymes responsible for the colour and aroma development of Rooibos tea, the disruption and maceration of the plant material during processing is insufficient to allow these enzymes proper access to the substrates responsible for Rooibos tea's characteristics. The current processing of Rooibos tea is also time consuming and is done under uncontrolled conditions, leading to unnecessary loss in aroma and antioxidant content. The addition of enzymes could improve the maceration of the plant material, shorten the processing time and improve the extraction of aroma, colour and antioxidant components. During this study, 16 commercially available microbial enzymes were evaluated on three different Rooibos substrates for the improvement of aroma and colour development, as well as the extraction of soluble solids (SS) and total polyphenols (TP). Thirteen enzymes were evaluated on spent tea for the enhanced extraction of soluble solids and to determine the best candidates for further evaluation on fermented and green Rooibos tea. Seven of the enzymes improved the yield in SS from spent tea. Up to 232% improvement was obtained, depending on the type of enzyme and dosage applied. The best six enzyme preparations were further evaluated on fermented Rooibos tea. For Depol™ 670L at 20 ul/g tea, the laboratory treatment increased the yield in SS by 44%, while small-scale industrial simulations increased the SS by 26%. However, an increase in the yield in SS was usually accompanied by a decrease in the %TP/SS ratio, indicating that mainly inactive compounds were extracted. Based on the results with the commercial enzymes, twelve "synthetic" enzyme cocktails, consisting of different combinations of commercial enzymes were designed, of which three cocktails released increased amounts of SS without decreasing the %TP/SS ratio significantly. Thirteen enzymes were evaluated on dried and freshly cut green Rooibos tea, with three enzymes (Depol™ 670L, Pectinex Ultra SP-L and Depol™ 692L) increasing the yield in SS between 21% and 66%, and the TP content between 11% and 47%. Laccase was the best candidate in improving colour development from green tea, with the improvement being slightly better at 50°C than at 40°C. All the "synthetic" cocktails containing laccase improved the colour extract of all three substrates evaluated, but also significantly decreased the TP and antioxidant content. However, lower dosages of laccase resulted in colour development with little loss in the antioxidant content. Due to the promising results obtained with the treatments of Rooibos tea with laccases, it was decided to clone and express the laccase gene (lacA) of Pleurotus ostreatus into Aspergillus niger. The gene was successfully transformed into A. niger, but the expression of the recombinant gene was not effective. / AFRIKAANSE OPSOMMING: Die Rooibostee plant (Aspalathus linearisi is inheems tot Suid-Afrika en kom slegs in die Sederberg-omgewing in die Wes-Kaap voor. Rooibostee word van die blare en fyn stingels van die plant geproduseer. Die tee word normaalweg voorberei deur die blare in kookwater te laat trek en dan die aftreksel te drink. Die Rooibos plant word nie net gebruik om tee te maak nie; die tee ekstrak word ook gebruik vir verskeie neutraseutiese en farmaseutiese produkte, insluitende gesondheidsdrankies, ystee, seep en bevogtigingsrome. Ten spyte daarvan dat die teeplant sy eie ensieme vir die kleur en aroma ontwikkeling van Rooibostee bevat, is die verbreking en maserasie van die plantmateriaal tydens prosessering onvoldoende om die ensieme genoeg toe gang tot die substrate verantwoordelik vir die kenmerkende eienskappe van Rooibostee te gee. Die huidige prosessering van Rooibostee is ook tydrowend en geskied onder onbeheerde toestande, wat tot 'n onnodige verlies in aroma en antioksidante lei. Die toevoeging van ensieme kan die afbraak van die plantmateriaal verbeter, die behandelingsproses verkort en die aroma, kleur en antioksidant inhoud van ekstrakte verbeter. Tydens hierdie studie is 16 kommersieel-beskikbare mikrobiese ensieme op drie verskillende Rooibos substrate vir die verbetering van aroma, kleur en ekstraksie van oplosbare vastestowwe (SS) en totale polifenole (TP) getoets. Dertien ensieme is op oorskot tee vir die verbeterde ekstraksie van oplosbare vastestowwe geevalueer, waama die beste kandidate vir evaluering op gefermenteerde en ongefermenteeede Rooibostee gekies is. Sewe ensieme het die SS vanaf oorskot tee verhoog. Tot 232% verhoging is waargeneem, afhangende van die tipe ensiem en die dosis wat gebruik is. Die beste ensiern preparate IS verder op gefermenteerde Rooibostee geevalueer, Labarotoriurn behandelings met Depol™ 670L teen 20 ul/g tee het die SS inhoud met 44% verhoog, terwyl die kleinskaalse industriele simulasie die SS inhoud met 26% verhoog het. 'n Verhoging in SS het egter gewoonlik met 'n afname in die %TP/SS verhouding gepaard gegaan, wat aandui dat hoofsaaklik onaktiewe stowwe vrygestel IS. Na aanleiding van die resultate met die kommersiele ensieme, is twaalf "sintetiese" ensiemmengsels met verskillende ensiemkombinasies getoets, waarvan drie mengsels ook meer SS vrygestel het met byna geen verlaging in die %TP/SS verhouding nie. Dertien ensieme was op gedroogde en vars gekerfde groen Rooibostee getoets met drie ensieme (Depol™ 670L, Pectinex Ultra SP-L en Depol™ 692L) wat die SS met tussen 21% en 66%, en die TP inhoud met tussen 11% en 47% verhoog het. Lakkase was die beste kandidaat vir die verbetering van kleur ontwikkeling by groen Rooibostee met die verbetering effens beter by 50°C as by 40°C. Al die "sintetiese" ensiem mengsels wat lakkase bevat het, het die kleur by al die verskillende substrate verbeter, maar het ook die TP en antioksidant inhoud aansienlik verlaag. Laer lakkase dosisse het goeie kleurontwikkeling tot gevolg gehad met minimale verlies in die antioksidant inhoud. Vanwee die goeie resultate wat met die lakkase behandelings verkry is, is daar besluit om die lakkase geen (lacA) van Pleurotus ostreatus te kloneer en in Aspergillus niger uit te druk. Die geen is suksesvol in A. niger getransformeer, maar die uitdrukking daarvan was nie effektief nie.

Herbal medicines are an important part of the African culture and tradition and about 80% of Africa’s population relies on traditional remedies for their primary health care needs (WHO, 2008). Athrixia phylicoides is widely used as a traditional remedy, but despite its substantial use, literature on its chemical composition and biological activities is limited. In this study, the chemical composition of the essential oil was determined using gas chromatography combined with mass spectroscopy (GC/MS) and analysis resulted in the identification of 182 compounds. The major compounds identified in selected samples were α-pinene, β-pinene, caryophyllene oxide, β-caryophyllene, myrcene and spathulenol. Based on the traditional uses of A. phylicoides, various in vitro biological activities were investigated. The extensive use of A. phylicoides for the treatment of boils, sores, bad acne, infected wounds and cuts, prompted the antimicrobial (bacterial and fungal) study using the minimum inhibitory concentration (MIC) assay. The methanol extract and essential oil were more selective for the Grampositive bacteria than the Gram-negative bacteria. The extract exhibited stronger activity against all micro-organisms tested compared to the essential oil, with the highest activity against S. aureus, B. cereus and B. subtilis (MIC = 1 mg/ml). The bioactive compound, (4-hydroxyphenyl) propyl coumaroate was isolated from the extract and proved to be most active against S. aureus (MIC = 19.5 μg/ml). Using the DPPH• assay, a comparative antioxidant study was performed. The anti-oxidant activity of the aqueous extract of A. phylicoides (IC50 = 14.01 ± 2.68 μg/ml) was greater than rooibos and Ceylon (black) tea (IC50 > 25.00 μg/ml); comparable to green rooibos and honeybush tea (IC50 = 18.01 ± 4.06 μg/ml; 18.02 ± 4.27 μg/ml, respectively), but less active than green tea (IC50 = 9.64 ± 0.96 μg/ml). The antimalarial activity was determined using the [3H] hypoxanthine incorporation method. The essential oil exhibited greater antimalarial activity against the chloroquine-resistant Plasmodium falciparum (FCR-3) strain (IC50 = 1.006 ± 0.06 μg/ml) than the methanol extract. The 5-lipoxygenase assay was used to assess the anti-inflammatory activity of the methanol extract and essential oil. Only the essential oil displayed anti-inflammatory activity (IC50 = 25.68 μg/ml). Low safety indices were reported for both the methanol extract (SI = 2.28) and essential oil (SI = 1.77). The in vitro biological activities may validate the use of A. phylicoides in traditional medicine.

<p>&nbsp / </p> <p align="left"><font face="Times New Roman">Aspalathus linearis (A. linearis), </font><font face="Times New Roman">commonly known as Rooibos tea or Red bush tea and </font><i><font face="Times New Roman">amellia sinensis (C. sinensis) </font></i><font face="Times New Roman">or Black tea are beverages that are consumed throughout the</font><font face="Times New Roman">world. These teas possess antioxidant, immunomodulating and anti-cancer actions. The aim</font> <font face="Times New Roman">of this study was to use <i>in vitro </i>assays to screen Rooibos and Black tea for endocrine</font> <font face="Times New Roman">modulation. </font><font face="Times New Roman">The immune modulating effects of Rooibos and Black tea were investigated using an <i>in vitro</i></font> <font face="Times New Roman">whole blood culture (WBC) assay. Unstimulated WBCs treated with Rooibos tea secreted</font> <font face="Times New Roman">higher levels of IL-6, IL-10 and IFN<font lang="JA">&gamma / </font>than cultures treated with DMSO control. Rooibos treatment of stimulated WBCs resulted in higher IL-6, lower IL-10 and no effect on IFN&gamma / </font><font face="Times New Roman">secretion compared to DMSO treated stimulated WBC. Black tea treatment of stimulated</font> <font face="Times New Roman">WBC resulted in decreased IL-6, IL-10 and IFN<font lang="JA">&gamma / </font>secretion compared to the DMSO treated</font> <font face="Times New Roman">stimulated WBC. </font><font face="Times New Roman">Extracts of Rooibos and Black tea were assessed for phytoestrogens using quantitative </font><font face="Times New Roman">estrogen ELISAs. Both teas contain phytoestrogens. The quantitative ELISAs showed that </font><font face="Times New Roman">Rooibos tea contained significantly lower estrone (E1), estradiol (E2) and estriol (E3) levels </font><font face="Times New Roman">than Black tea. The effects of Rooibos and Black tea on proliferation of the estrogen</font> <font face="Times New Roman">dependant MCF-7 cell line was determined to further characterise the phytoestrogenic</font> <font face="Times New Roman">properties of the teas. Both Rooibos and Black tea extracts caused a significant inhibition of</font> <font face="Times New Roman">MCF-7 proliferation. </font><font face="Times New Roman">This study shows that Rooibos tea and Black tea are beverages that can either stimulate or </font><font face="Times New Roman">suppress the immune system. Also, both teas contain significant levels of phytoestrogens as </font><font face="Times New Roman">determined by quantitative ELISAs. The current study confirms previous reports showing </font><font face="Times New Roman">inhibition of growth in breast cancer cell lines by phytoestrogens. The findings extend </font><font face="Times New Roman">related observations on the anti-carcinogenic potential of the two teas.</font></p>

<p>&nbsp / </p> <p align="left"><font face="Times New Roman">Aspalathus linearis (A. linearis), </font><font face="Times New Roman">commonly known as Rooibos tea or Red bush tea and </font><i><font face="Times New Roman">amellia sinensis (C. sinensis) </font></i><font face="Times New Roman">or Black tea are beverages that are consumed throughout the</font><font face="Times New Roman">world. These teas possess antioxidant, immunomodulating and anti-cancer actions. The aim</font> <font face="Times New Roman">of this study was to use <i>in vitro </i>assays to screen Rooibos and Black tea for endocrine</font> <font face="Times New Roman">modulation. </font><font face="Times New Roman">The immune modulating effects of Rooibos and Black tea were investigated using an <i>in vitro</i></font> <font face="Times New Roman">whole blood culture (WBC) assay. Unstimulated WBCs treated with Rooibos tea secreted</font> <font face="Times New Roman">higher levels of IL-6, IL-10 and IFN<font lang="JA">&gamma / </font>than cultures treated with DMSO control. Rooibos treatment of stimulated WBCs resulted in higher IL-6, lower IL-10 and no effect on IFN&gamma / </font><font face="Times New Roman">secretion compared to DMSO treated stimulated WBC. Black tea treatment of stimulated</font> <font face="Times New Roman">WBC resulted in decreased IL-6, IL-10 and IFN<font lang="JA">&gamma / </font>secretion compared to the DMSO treated</font> <font face="Times New Roman">stimulated WBC. </font><font face="Times New Roman">Extracts of Rooibos and Black tea were assessed for phytoestrogens using quantitative </font><font face="Times New Roman">estrogen ELISAs. Both teas contain phytoestrogens. The quantitative ELISAs showed that </font><font face="Times New Roman">Rooibos tea contained significantly lower estrone (E1), estradiol (E2) and estriol (E3) levels </font><font face="Times New Roman">than Black tea. The effects of Rooibos and Black tea on proliferation of the estrogen</font> <font face="Times New Roman">dependant MCF-7 cell line was determined to further characterise the phytoestrogenic</font> <font face="Times New Roman">properties of the teas. Both Rooibos and Black tea extracts caused a significant inhibition of</font> <font face="Times New Roman">MCF-7 proliferation. </font><font face="Times New Roman">This study shows that Rooibos tea and Black tea are beverages that can either stimulate or </font><font face="Times New Roman">suppress the immune system. Also, both teas contain significant levels of phytoestrogens as </font><font face="Times New Roman">determined by quantitative ELISAs. The current study confirms previous reports showing </font><font face="Times New Roman">inhibition of growth in breast cancer cell lines by phytoestrogens. The findings extend </font><font face="Times New Roman">related observations on the anti-carcinogenic potential of the two teas.</font></p>