published_or_final_version / abstract / toc / Dentistry / Doctoral / Doctor of Philosophy

published_or_final_version / Zoology / Master / Master of Philosophy

published_or_final_version / Medicine / Master / Master of Philosophy

The metaphor of weaving and the methodology of phenomenology are used to expose eight ordinary people’s lived experience of receiving client-centred occupational therapy at home. This qualitative study reveals the themes of Thread, Weave and Texture interlocking to create the phenomenological structure of the lived experience. The two threads of being acknowledged and being respected are used with the five weaves of listening, taking time, demonstrating, having knowledge, and projecting a positive attitude, building four simple textures. The four textures -- having opportunity for choice, receiving support, getting information, and being cared about -- blended to form the participants’ lived experience. Their stories have inspired me to weave a tapestry of words, something that in its beauty celebrates the delivery of client-centred occupational therapy but also teaches these principles. / ix, 111 leaves ; 29 cm.

The emergence of multidrug resistant tumours during the course of chemotherapeutic treatment of cancer patients is a major obstacle in cancer chemotherapy. Although several mechanisms may contribute to the appearance of multidrug resistance phenotype (MDR) in tumour cells, reduced drug accumulation and the ability of cells to undergo apoptosis are thought to be very important in expression of MDR. The work in this thesis focuses on the mechanism responsible for the reduced drug accumulation in tumour cells, mainly the multidrug resistance protein (MRP1). / The molecular mechanism underlying the binding and efflux of drugs by the MRP1 is currently not well understood. Several studies have now demonstrated that the cysteinyl leukotriene C$ sb4$ (LTC$ sb4$) and other glutathione (GSH) S-conjugated anions are substrates for the MRP. To learn more about MRP-drug interactions, we characterized the binding of MRP to a non-glutathione photoactive quinoline compound (abbreviated, ASA-AQ) (Chapter II). Since MRP mediated multi-drug resistance can be modulated by the anionic quinoline LTD$ sb4$ cysteinyl leukotriene receptor antagonist (MK571), we speculated that other quinoline-based compounds are likely to interact with MRP. In Chapter III, we show that MDR cells that express MRP1 are more resistant to the antimalarial drug, chloroquine. We also show that. chloroquine is a substrate for MRP1 drug efflux. / Taken together, the results of this thesis describe the interactions of MRP1 with a quinoline-based photoactive drug and the antimalarial drug chloroquine.

Treatment delivery verification is an essential step of radiotherapy. The purpose of this thesis is to develop new methods to improve the verification of photon and electron beam radiotherapy treatments. This is achieved through developing and testing (1) a way to acquire portal images during electron beam treatments, (2) a method to reconstruct the dose delivered to patients during photon beam treatments and (3) a technique to improve image quality in kilovoltage (kV) cone beam computed tomography (CBCT) by correcting for scattered radiation. The portal images were acquired using the Varian CL21EX linac and the Varian aS500 electronic portal imaging device (EPID). The EGSnrc code was used to model fully the CL21EX, the aS500 and the kV CBCT system. / We demonstrate that portal images of electron beam treatments with adequate contrast and resolution can be produced using the bremsstrahlung photons portion of the electron beam. Monte Carlo (MC) calculations were used to characterize the bremsstrahlung photons and to obtain predicted images of various phantoms. The technique was applied on a head and neck patient. / An algorithm to reconstruct the dose given to patients during photon beam radiotherapy was developed and validated. The algorithm uses portal images and MC simulations. The primary fluence at the detector is back-projected through the patient. CT geometry to obtain a reconstructed phase space file. The reconstructed phase space file is used to calculate the reconstructed dose to the patient using MC simulations. The reconstruction method was validated in homogeneous and heterogeneous phantoms for conventional and IMRT fields. / The scattered radiation present in kV CBCT images was evaluated using MC simulations. Simulated predictions of the scatter distribution were subtracted from CBCT projection images prior to the reconstruction to improve the reconstructed image quality. Reducing the scattered radiation was found to improve contrast and reduce shading artifacts. / MC simulations, in combination with experimental techniques, have been shown to be valuable tools in the development of treatment verification methods. The three novel methods presented in this thesis contribute to the improvement of radiotherapy treatment verification. They can potentially improve treatment outcome by ensuring a better target coverage.

Wernicke's encephalopathy is a neuropsychiatric disorder resulting from thiamine deficiency (TD) and is characterized by neuronal loss, astrocytic proliferation and microglial activation. Cyclooxygenases (COX) are enzymes which catalyze the first step in the synthesis of prostanoids. COX-1 is expressed constitutively and COX-2 is the inducible isoform. Groups of TD rats and pair-fed controls were killed at presymptomatic and symptomatic stages of encephalopathy. Cresyl violet and NeuN staining showed decreased numbers of neuronal cells in vulnerable regions (medial thalamus and inferior colliculus) but not in a spared region (frontal cortex). Numbers of GFAP-positive and OX-42-positive cells were increased at symptomatic stage of encephalopathy. Expression of COX-2 mRNA and neuronal COX-2 immunoreactivity were selectively increased in vulnerable regions of TD rats at symptomatic stages of encephalopathy. Nimesulide, a highly selective COX-2 inhibitor, lowered PGE2 levels and precipitated the progression of encephalopathy suggesting that COX-2 in this model is conferring neuroprotection.

Patients with end-stage renal disease undergoing hemodialysis have a high incidence of oxidative stress-related diseases. This study evaluated oxidative stress and inflammatory markers in patients undergoing hemodialysis before and during vitamin E supplementation. Blood samples were obtained before and after dialysis during two separate dialysis sessions to establish baseline measurements. For the next two months, subjects consumed 400 IU RRR-α-tocopherol daily. At one month and two months of supplementation, blood samples were also obtained before and after dialysis. Circulating concentrations of α- and γ-tocopherols and their metabolites (carboxyethyl-hydroxychromans, α- and γ-CEHCs), vitamin C, and uric acid were determined by HPLC with electrochemical detection. C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were measured using standard clinical assays. F₂-isoprostanes were evaluated using an enzyme immunoassay. Dietary vitamins E and C were assessed using two 24-hour recalls. In response to vitamin E supplementation, plasma α-tocopherol concentrations increased from 18 ± 1.7 μM to 31 ± 5.4 μM (p<0.0001), while γ-tocopherol concentrations decreased from 2.8 ±1.0 μM to 1.7 ± 0.6 μM (p=0.001). Additionally, serum vitamin E metabolites increased, α-CEHCs from 68 ± 20 pmol/ml to 771 ± 161 (p<0.0001) and γ-CEHC from 837 ± 161.8 pmol/ml to 1136 ± 225.9 (p=0.0083). Both CEHCs are well above reported normal values (p<0.0001). Dietary antioxidants (vitamins E and C) were low in most subjects; thus, plasma ascorbic acid levels were low in most subjects, but high in a few, resulting a wide range of responses (88 ± 84 μM). Nonetheless, ascorbic acid concentrations decreased significantly after dialysis to 33 ± 34 μM (p=0.0124), but were unaffected by vitamin E supplementation. Indeed, many parameters decreased significantly by dialysis but were unchanged by vitamin E supplementation, including plasma concentrations of uric acid and TNF-α. Both IL-6 and F₂-isoprostane concentrations were elevated in the subjects but were unaffected by either vitamin E supplementation or dialysis. CRP increased significantly after dialysis (p=0.0161, ANOVA main effect), but in the vitamin E supplemented subjects CRP concentrations were slightly lower before dialysis , but increased following dialysis (p=0.0041, ANOVA interaction). Taken together, the data suggest that there is a complex relationship between chronic inflammation and oxidative stress. Longer supplementation with vitamin E might be necessary in order to observe beneficial effects. / Graduation date: 2003

Helicobacter pylori infects more than half of the global population and causes gastric disorders. The increasing development of antibiotic resistance by the bacterium continues to limit treatment options. The identification and characterisation of novel therapeutic targets are necessary for successful future treatment of the infection. One potential target for therapeutic intervention is the gpt gene encoded by hp0735 (jhp0672) in H. pylori strain 26695 (J99). This gene produces a putative xanthine-guanine phosphoribosyltransferase (XGPRTase), an enzyme of the purine salvage synthesis pathway. This project employed theoretical, molecular and biochemical approaches to investigate features of H. pylori gpt and XGPRTase that will serve to ascertain their therapeutic potential. The production of a functional XGPRTase by H. pylori was investigated in cell-free extracts, and the kinetic parameters of this activity were compared to those of purified rXGPRTase enzyme. The three 6-oxopurine substrates were recognised by rXGPRTase and allosteric kinetics were observed for some substrates of the enzyme in cell-free extracts and for purified enzyme. These observations indicate complex regulation and an influence of cellular interactions on activity. Bioinformatics were employed to analyse XGPRTase phylogeny, and threading techniques used to build a structural model of XGPRTase. The enzyme is significantly divergent from the equivalent mammalian enzyme, and modelling identified specific features of the enzyme. Molecular approaches were utilised to analyse the essential role of gpt in H. pylori survival. These included insertional inactivation of the gpt in wild-type H. pylori strains and in mutants possessing a complementing copy of the gene present at the rdxA locus. No mutants were recovered with inactivated gpt possibly as a result of pleiotropic effects. Plasmid-mediated complementation was attempted employing IPTG-inducible shuttle vectors and did not yield any mutants. Further characterisation of H. pylori XGPRTase was performed by determining the effects of nucleotide monophosphates and purine analogues on enzyme activity. Inhibition by GMP was observed in all cases, however differences in the inhibition by other nucleotide monophosphates were found between cell-free extracts and the recombinant enzyme. Inhibition of rXGPRTase activity was observed by the purine analogue 6-mercaptopurine ribose, a compound that previously has been shown to inhibit H. pylori growth in culture.

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The aim of the work described in this thesis was initially to screen the ethanol extracts of eleven Indonesian ginger species (Zingiberaceae family) for anticancer activity. MCF-7 breast and HT-29 colon cancer cells were used for the investigations. Extracts of Zingiber aromaticum and Boesenbergia pandurata were found to be the most active species, similar to that of Curcuma langa which has been shown to possess anticancer activity in vitro and in vivo (Aruna and Sivaramakrishnan, 1992; Azuine and Bhide, 1992). These two active species were then further investigated. Bioactive compounds from the species were isolated and identified using various chromatography procedures and nuclear magnetic resonance (NMR) and their anticancer activities were further tested on MCF-7 breast and HT-29 colon cancer cells including cell cycle analysis and measurements of apoptosis. The ethanol extracts of these two active species were also investigated using the AOM-induced colon cancer model in rats. The antiinflammatory activity of the ethanol extract of Z. aromaticum was also investigated using dextran sulfate sodium (DSS) induced ulcerative colitis (UC) in rats. The inhibitory activity of ethanol extracts of rhizomes of 11 ginger species was initially tested against MCF-7 breast and HT-29 colon cancer cells using colorimetric tetrazolium salt (MTT) assay. Ethanol extracts of eight species (Amommum cardamomum, C. longa, C. mangga, C. xanthorrhiza, Boesenbergia pandurata, Zingiber aromaticum, Z. officinale, Z. cassumunar) showed a strong inhibitory effect on the growth of the cancer cells with the IC50 concentrations between 100-100 g/ml. The ethanol extract of Curcuma aeruginosa was less active (IC5o between 100-120 g/ml) and extracts of Kaempferia galangal and K. rotunda had no effect on the growth of either cell lines at concentrations up to 250 g/ml. Ethanol extract of C. longa was used as a comparison since curcumin, an active compound isolated from this species, has had demonstrated its anticancer activity in vitro, in vivo and is currently undergoing clinical trial against colon cancer (Greenwald, et al., 2001; Sharma et al., 2001). Extracts of Z. aromaticum and B. pandurata had very strong inhibitory activity similar to the extract of C. longa. Curcumin was not detectable in either Z. aromaticum or B. pandurata. The ethanol extracts of the active species were not toxic on human skin fibroblast cells (SF 3169). The ethanol extracts of Z. aromaticum and B. pandurata were further fractionated using two different solvents by reversed phase preparative HPLC. Fraction A was eluted with a mobile phase containing 5% vlv aqueous methanol containing 0.025% v/v trifluoroacetic acid (TFA) and fraction B was eluted with 100% methanol. The inhibitory activity of fractions was then investigated against HT-29 colon cancer cells and assayed using the MTT assay. Zerumbone, a sesquiterpenoid compound was isolated from fraction B of the extract of Z. aromaticum and a chalcone derivative, panduratin A was isolated from fraction B of the extract of B. pandurata. Curcumin was in fraction A of extract of C. longa. The anticancer activity of zerumbone and panduratin A was investigated using MCF-7 breast. HT-29 and CaCo-2 colon cancer cells. The inhibitory activity of the active compounds was assessed using the MTT assay. The ICso of zerumbone in each of the cell lines was about 10 uM and of curcumin on HTU29 cells was 25 uM. The IC50 of panduratin A in HT-29 cells was 16 uM and in MCF-7 cells was 9 uM. Zerumbone and panduratin A showed antiproliferative effects by alteration of the DNA distribution in the cell cycle and induction of apoptosis. HT-29 cells treated with zerumbone at concentrations of 10 -25 uM or panduratin A at concentrations of 9 -65 uM for 24 h were stained with propidium iodide (PI) to determine cell cycle distribution and analysed using FACScan flow cytometry. The proportion of cells in the S phase was reduced from 18.7% in untreated cells to 10.2% in HT-29 cells after treatment with zerumbone at 10 uM to 3.1% at 25 uM. Cells in the G2 phase increased from 18.5% at 10 uM to 40% at a concentration of 25 uM. Panduratin A increased the proportion of cells in the GO/G1 phase from 33% of untreated cells to 71% after treatment with 65 uM for 24 h. Panduratin A slightly reduced the proportion of cells in S phase and cells in G2/M phase also decreased from 36,8% in untreated cells to 15.4% at 65 M. Apoptosis was determined using double labelled (Annexin-V-Fluos and PI) and then evaluated using FACScan Flow Cytometry. Morphological features of apoptosis were also examined using DiffQuick stain and fluorescent Hoechst 3355 and 4,6-diamino-2-phenylindole (DAPI). Zerumbone induced apoptosis in HT-29 cells in a dose dependent rnanner, At 48 h, 2% of cells treated with 10 M of zerumbone underwent apoptosis, which increased to 8% when treated with 50 M, Panduratin A at 28 M increased the number of cells undergoing apoptosis from 2,2% to 16.7% when treated with a concentration of 65 M. The ethanolic extracts of Z. aromaticum and B. pandurata were also investigated using the azoxymethane (AOM) induced aberrant crypt foci (ACF) model of colon cancer in rats in a short and long term study. Ethanolic extracts of C. tonga and curcumin were used as comparison. The basal diet used throughout all animal studies in this thesis was a semi-purified AIN-93 G diet (Reeves et aI., 1993). ACF were induced by two doses (15 mg/kg BW) subcutaneously of AOM one week apart and ACF were visualised in the formalin fixed colon using methylene blue stain. The ACF study was run over a short (5 weeks) and long (13 weeks) experiments. Diets containing ethanol extracts prepared from the equivalent of 2% (w/w) dried rhizome of Z. aromaticum, B. pandurate or C. tonga in a short term study did not affect the formation of ACF in rats compared to those in the control diet group. The ACF formation in a short term study was dominated by small numbers of aberrant crypts (1 or 2) per focus. It is suggested that large ACF (4 or more ACs/focus) are better predictors of colon cancer (Uchida et aI., 1997; Jenab et aI., 2001). Diets containing ethanol extracts of the equivalent of 4% by weight of dried rhizomes of Z. aromaticum, B. pandurata, C. longa were investigated over 13 week study, Total ACF were significantly reduced by Z. aromaticum extract (0.34%) in the diet (down 21%, p<0.05) relative to rats fed the control diet. A similar reduction was observed with C, longa extract (0.86%) in the diet (down 24%, p<0.01) and with 2000 ppm curcumin. There was no significant different in small ACFs (1-2 ACs/ focus) between dietary treatments. The number of foci containing 3-4 ACs/focus was significantly reduced (35%, p<0,001) in animals fed the Z. aromaticum extract and 34% (p<0.001) of animals fed the C. tonga extract. The total number of ACF containing 5 or more ACs per focus of animals fed 0.34% Z. aromaticum extract was 41 % lower than control (p<0.05) and for 0.86 % C. tonga extract was 22% (not significant). A diet containing extract (0.56%) of B. pandurata did not significantly affect the formation of ACF compared to the control AIN group. The concentration of zerumbone in the Z.aromaticum extract diet was assayed at 300 ppm, and of curcumin in the C. tonga extract diet was also 300 ppm. The concentration of panduratin A was not assayed in the diet due to late identification of the active compound. The antiinflammatory activity of ethanol extract of Z. aromaticum was investigated using dextran sulfate sodium (DSS) induced ulcerative colitis in rats. Sulfasalazine, a widely used compound to treat inflammatory bowel disease (IBD) in humans was used as the positive control. Diets containing ethanol extracts (0.34% and 0.68%) prepared from the equivalent of 4% and 8% by weight of dried rhizomes of Z. aromaticum were given to the animals throughout the experiment. On day three, rats were given 2% DSS in drinking water for 5 d and then just water for 3 d and then were killed. During the DSS treatment rats were maintained in metabolic cages, body weight, food and fluid intake and clinical symptoms such as consistency of stools and blood in faeces were recorded daily. There was slight but not significant reduction in the body weight of rats fed 0.68% extract of Z. aromaticum in the diet due to reduced food consumption. The extract of Z. aromaticum (0.34%) and sulfasalazine suppressed clinical signs of ulcerative colitis. Eleven percent of the controls were hemoccult positive on day 2 after DSS administration, which progressed further by day three with 67% being hemoccult positive and 100 % on day five. By comparison, blood appeared on day 3 of rats treated with diet containing 0.34% and 0.68% extract of Z. aromaticum and 0.05% sulfasalazine, and only 33%, 67% and 22%, of rats being hemoccult positive on day 5 respectively. The disease activity index (DAI) of rats fed diet containing 0.34% extract of Z. aromaticum was about 0.4 and similar to those which were fed with diet containing sulfasalazine. The DAI of untreated rats was 1.4. The crypt score of rats fed the extract of Z. aromaticum was slightly reduced but it was not significantly different from those of untreated rats. Other histological scores were not significantly different between dietary treatments. Extract of Z. aromaticum significantly decreased the content of PGE-2 in colon tissue compared to that of untreated animals. There was a reduction of TX8-2 content in colonic tissue of rats fed with extracts of Z. aromaticum but this was not significant. The activity of myeloperoxidase (MPO) activity in the colonic tissue of rats fed with sulfasalazine was significantly lower than that of the untreated controls and those which fed with extracts of Z. aromaticum. The results from the studies performed in this thesis showed that extract of Z. aromaticum which contains an active sesquiterpenoid zerumbone have anticancer and antiinflammatory activity suggesting that the extract may have benefits as a chernopreventative agent. However further studies are needed to elucidate their other pharmacological actions. Panduratin A showed potential anticancer activity in cell culture in vitro. However an extract of B. pandurata did not have effect on the AOM-induced colon cancer model. Different cancer models such as breast and prostate cancer could be used to further investigate the anticancer activity of extract of B. pandurata and panduratin A and to elucidate their mechanism. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1097849 / Thesis (Ph.D.) -- University of Adelaide, Dept of Medicine, 2003