Includes list of publications arising from this thesis / Erratum attached to inside back cover. / "25/03/2004." / Includes bibliographical references (leaves 185-257) / xii, 257 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Medicine and Royal Adelaide Hospital, Rheumatology Unit, 2004

Adverse effects of cyclooxygenase (COX) inhibitors on bone healing have previously been demonstrated in diaphyseal fracture models in animals. In spite of that, they are widely used as postoperative analgesics in orthopaedic surgery. After joint replacement, a bone repair process starts at the interface between bone and cement. If this process is disturbed, the prosthesis may never become rigidly fixed to the bone, leading to migration and with time loosening. This thesis investigates the effects of a selective COX-2 inhibitor (parecoxib or celecoxib) on bone healing in metaphyseal bone in a rat model and on knee prosthesis migration after total knee replacement, as measured with radiostereometric analysis. Blood loss, postoperative recovery, and the 2-year subjective outcome, were also measured. In addition, a hemoglobin dilution method for blood loss estimation, used in this thesis, was evaluated. In the first study, pull-out force of a screw inserted in metaphyseal bone of the tibia in rats was only marginally decreased by parecoxib after 7 days but not after 14 days. In the second and third study, celecoxib treatment resulted in less pain postoperatively in conjunction with total knee replacement (TKR), but no effects were seen on blood loss, range of motion, subjective outcome, or prosthesis migration after 2 years. Comparing the true blood loss of blood donors with the blood loss estimated by the hemoglobin dilution method, this method was found to underestimate the true blood loss. It is therefore not suitable for calculation of the absolute blood loss volume, but may be used for a rough estimate. In summary, celecoxib and presumably other cyclooxygenase inhibitors seems not likely to increase the risk of prosthesis loosening.

Stable single-unit recordings from the nervous system using microelectrode arrays can have significant implications for the treatment of a wide variety of sensory and movement disorders. However, the long-term performance of the implanted neural electrodes is compromised by the formation of glial scar around these devices, which is a typical consequence of the inflammatory tissue reaction to implantation-induced injury in the CNS. The glial scar is inhibitory to neurons and forms a barrier between the electrode and neurons in the surrounding brain tissue. Therefore, to maintain long-term recording stability, reactive gliosis and other inflammatory processes around the electrode need to be minimized. This work has succeeded in the development of neural electrode coatings that are capable of sustained release of anti-inflammatory agents while not adversely affecting the electrical performance of the electrodes. The effects of coating methods, initial drug loadings on release kinetics were investigated to optimize the coatings. The physical properties of the coatings and the bioactivity of released anti-inflammatory agents were characterized. The effect of the coatings on the electrical property of the electrodes was tested. Two candidate anti-inflammatory agents were screened by evaluating their anti-inflammatory potency in vitro. Finally, neural electrodes coated with the anti-inflammatory coatings were implanted into rat brains to assess the anti-inflammatory potential of the coatings in vivo. This work represents a promising approach to attenuate astroglial scar around the implanted silicon neural electrodes, and may provide a promising strategy to improve the long-term recording stability of silicon neural electrodes.

South Africa is home to a wide diversity of cultural groups, all of which utilize the flora for a variety of purposes. This is true with regard to traditional medicine systems which are similar to those of the rest of Africa south of the Sahara, with diviners (sangomas) and herbalists (inyangas) as the key health providers. In addition, the Country is rich in plant diversity with some 30 000 species of flowering plants - almost one tenth of the worlds recorded higher plants. This incorporates a large diversity of plants including trees, shrubs, herbs, bulbs and corms. The adverse effects of traditional medicinal plants and natural products are not well documented in the literature. Recently, many plants used as food or in traditional medicine have been shown to be potentially mutagenic using in vitro assays. Thus, the scientific evaluation of traditional medicine and medicinal plants is very important to validate claims made on safety and efficiency of such usages. After a survey of the available ethnobotanical literature, ten trees used in South African traditional medicine were selected. These species were: Acacia niolotica subspecies kraussiana, Acacia sieberiana, Albizia adianthifolia, Combretum kraussii, Faidherbia albida, Ficus sur, Prunus africana, Salix mucronata, Terminalia sericea and Trichilia dregeana. Plant parts including leaf, root and bark were collected from each of the selected trees (exceptions were Albizia adianthifolia, Faidherbia albida, Terminalia sericea and Prunus africana) and extracted using ethyl acetate, ethanol and water individually to ensure the extraction of compounds over a wide range of polarities. The extracts (in total, 78) were screened for antibacterial, anti-inflammatory (COX-1 and COX-2) and antiacetylcholinesterase activities and investigated for their potential mutagenic effects using the Ames test. Antibacterial activity was detected using the disc-diffusion and microdilution assays. The extracts were tested against Gram-positive bacteria: Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus and Gram-negative bacteria: Escherichia coli and Klebsiella pneumoniae. Of the 78 different plant extracts 111 tested (final amount of plant material was 1 mg per disc), 84% showed activity against Gram-positive bacteria. From this percentage, 20% also showed activity against Gram-negative bacteria. The best inhibition was observed with ethyl acetate and ethanol root extracts of Terminalia sericea against both Gram-positive and Gram-negative bacteria. In the micro-dilution assay, 55% of the plant extracts showed minimum inhibitory concentration (MIC) values ~ 1.56 mg/ml against Gram-positive and/or Gram-negative bacteria. The ethyl acetate bark extract of Acacia sieberiana and the root and bark ethyl acetate extracts of Acacia nilotica inhibited bacterial growth of both Gram-positive and Gram-negative bacteria at concentrations ~ 0.8 mg/ml. The aqueous leaf extracts of Acacia sieberiana had a low MIC value (0.3 mg/ml) against Gram-negative Kleibsiella pneumoniae and the ethyl acetate extracts of the root inhibited growth of Escherichia coli with an MIC value of 0.1 mg/ml. However, these two extracts showed no activity in the disc-diffusion assay. The MIC values of the neomycin (control) were 0.8 I-Ig/ml and 3.1 I-Ig/ml against Kleibsiella pneumoniae and Escherichia coli respectively. In the anti-inflammatory test, 70% of the plant extracts from different plant parts (leaf, root, bark) of the tree investigated showed strong inhibition in both the CQX-1 and CQX-2 bioassays. The CQX-2 inhibitory effects of aqueous extracts were generally lower when compared to the organic solvent extracts. However, water extracts of Acacia nilotica was an exception (~ 90%). In the acetylcholinesterase inhibitory test, 21% of the plant extracts were active at concentrations ~ 1 mg/ml using the micro-plate assay. The lowest IC50 value was 0.04 mg/ml obtained with an ethanol bark extract of Combretum kraussii. The IC50 value of the galanthamine (positive control) was 2 I-IM. None of the investigated plants showed any potential mutagenic effects with Salmonella typhymurium strain TA 98 using the Ames test. Using bioassay-guided fractionation, anolignan B was isolated from the ethyl acetate root extract of Terminalia sericea. Antibacterial activity of anolignan B was determined using the microdilution assay. The compound possessed activity against both Gram-positive and Gram-negative bacteria. The lowest MIC value (3.8 IJg/ml) was observed with Staphylococcus aureus. MIC value of the neomycin was 1.5 IJg/ml. Anti-inflammatory activity of anolignan B was detected using the CQX-1 and CQX-2 bioasays. The compound showed strong inhibitory activity against CQX-1 and weaker activity against CQX-2. The ICso values were 1.5 mM and 7.5 mM with CQX-1 and CQX-2 respectively. The ICso values of indomethacin were 0.003 mM and 0.186 mM against CQX-1 and CQX-2 respectively. There were no potential mutagenic effects showen by anolignan B against Salmonella typhimurium strain TA 98 in the Ames test. Isolation of anolignan B from Terminalia species and the antibacterial and anti-inflammatory activities observed in this work have not been reported previously and could therefore be recorded as novel biological activities for this compound. These results also support the idea that the use of ethnobotanical data can provide a valuable short cut by indicating plants with specific uses which might likely be sources of biologically active chemicals. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Petroleum ether, dichloromethane, and 80% ethanol extracts of 15 plant species collected in Nigeria were screened for in vitro antibacterial, anti-inflammatory and antimalarial activities. Antibacterial activity was tested using the agar diffusion method, while the minimum inhibitory concentrations (MIC) of the active extracts were determined using the microtitre serial dilution method. Most antibacterial activity detected was against Gram-positive bacteria with Staphylococcus aureus being the most susceptible. The highest activity was found in petroleum ether and dichloromethane leaf extracts of Mallotus oppositifolius; petroleum ether, dichloromethane and ethanolic root extracts of Newbouldia laevis; and ethanolic root extracts of Morinda lucida and Canthium subcordatum. Against the Gram-negative bacterium Escherichia coli, the highest activity was found in dichloromethane leaf extracts of Newbouldia laevis, ethanolic root extracts of Phyllanthus amarus, Mallotus oppositifolius, and Canthium subcordatum. A total of 60 plant extracts were screened for antiplasmodial activity. A chloroquine sensitive strain of Plasmodium falciparum (D10) was used. In the assay, the parasite lactate dehydrogenase (pLDH) activity was used to measure parasite viability. About 11 extracts showed promising activity with an IC₅₀ ranging from 2.5 to 13.4 µg/ml. The petroleum ether leaf extract of Hyptis suaveolens had the highest activity (IC₅₀ = 2.5 µg/ml). The cyclooxygenase (COX-1 and COX-2) assays were used to test for anti-inflammatory activity. All the plant species, with the exception of Hedranthera barteri and Picralima nitida showed anti-inflammatory activity. Apart for a few ethanolic extracts, all the activities were recorded with petroleum ether and dichloromethane extracts. Employing bioassay-guided activity fractionation, an antibacterial anthraquinone identified as emodin was isolated from ethanolic root extract of Senna occidentalis. Although this compound had been isolated from other sources, this was the first report of isolation from Senna occidentalis. Using a similar approach a novel antimalarial diterpenoid was isolated from the petroleum ether leaves extract of Hyptis suaveolens. It had IC₅₀ of 0.1 µg/ml. This new compound is worthy of further investigation and may act as an important lead compound for future antimalarial drugs. / Thesis (Ph.D.)-University of KwaZulu-Natal, 2005.

[Truncated abstract] In recent years a better understanding of the biology of PPAR , a nuclear transcription factor, has emerged, leading to a resurgence in targeting PPAR for chemotherapy. The family of synthetic PPAR agonists, the thiazolidinediones (TZDs), and non-steroidal anti-inflammatory drugs (NSAIDs) have been implicated in the inhibition of cell proliferation, apoptosis and cell cycle arrest of androgen-sensitive (LNCaP) and androgen-independent (PC-3 and DU145) prostate cancer cells generating much interest in their use for potential curative cancer therapies. In light of the potential use of TZDs and NSAIDs in prostate cancer prevention and their ability to induce inhibitory effects in vitro and in vivo, the first aim of this project was to undertake a comprehensive study of the effects of ciglitazone (TZD) and indomethacin (NSAID) on the androgen-independent prostate cancer cell line DU145, using standardised concentrations and time-points to compare the effects of TZDs and NSAIDs on cell proliferation, cell cycle and apoptosis. Treating the cells with either 10 µM ciglitazone or 10 µM indomethacin resulted in a time-dependent decrease in DU145 cell proliferation. The anti-proliferative effects were found to be in-part attributed to the slowing of cell progression through the G1/S-phase checkpoint of the cell cycle, and in the case of ciglitazone, apoptosis also played a role in its anti-proliferative effects in this cell line. Interestingly, although indomethacin failed to induce apoptosis, its antiproliferative effects were more potent than ciglitazone. The second aim of this project was to further investigate the underlying mechanisms responsible for the anti-proliferative effects of ciglitazone and indomethacin by evaluating their ability to modulate PPAR mRNA and protein expression, and to induce PPAR transcriptional activity. ... In addition, ligandinduced regulation of secreted frizzled related protein 4 (sFRP4) expression, a Wnt/ - catenin antagonists, was investigated. It was demonstrated that both ciglitazone and indomethacin attenuated Wnt/ -catenin signalling via the down-regulation of total - catenin levels within the cells, inhibition or slowing of the translocation of cytoplasmic -catenin into the nucleus and inhibition of cyclin–D1 expression An inverse relationship between PPAR and -catenin protein levels was also detected, suggesting that PPAR may directly bind to -catenin itself. sFRP4 expression was transiently upregulated by ciglitazone and indomethacin-treatment, suggesting that the antiproliferative effects of the ligands may be mediated in part through regulation of sFRP4 mRNA and protein levels. In summary, the anti-proliferative effects of ciglitazone and indomethacin on the androgen-independent prostate cancer cell line, DU145, described in this thesis are progressive steps in characterising the role of PPAR in prostate cancer cell proliferation. The identification of indomethacin as a more potent PPAR agonist than ciglitazone represents a novel target for the development of preventative strategies for advanced disease, and the relationship between PPAR and the Wnt/ -catenin signalling pathway provide an insight into the mechanisms involved in the anti-proliferative effects of ciglitazone and indomethacin. Further studies into this relationship would advance help identify novel preventative and curative therapeutic strategies for advanced prostate cancer.

Bibliography: leaves 211-260 / xvii, 260 leaves ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Pathology, 1986

Activation of spinal N-methyl-D-aspartate (NMDA) receptors stimulates cyclooxygenase and nitric oxide pathways. Compounds that block the activity of these NMDA receptor systems reduce pain hypersensitivity. However, their usefulness is limited by the side effects they produce. One way of reducing side effects is by combining drugs that produce the same overt effect by different mechanisms, which hopefully increase the net effect. In these series of studies, drugs that interact with NMDA receptor systems and their combinations were screened in vitro to identify spinal antinociceptive synergistic combinations that could be assessed in vivo. Based on developmental changes in thresholds, conduction velocities and blocking actions of the local anaesthetic lignocaine in neonatal rat L4/L5 dorsal root potentials, it was decided to use spinal cord in vitro preparation from 5- to 7-day-old rat pups. In single drug studies, the NMDA receptor channel blocker ketamine (1-50 µM) and the non-steroidal anti-inflammatory drug (NSAID) ketoprofen (200-600 µM), but not the NSAID salicylate (1000 µM) and the nitric oxide synthase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME; 1-100 µM), reduced spinal NMDA receptor-mediated transmission. Ketamine also depressed non-NMDA receptor-mediated transmission. Using isobolographic and composite additive line analyses, fixed-ratio combinations of ketamine and ketoprofen, ketamine and L-NAME, and ketopofen and L-NAME synergistically depressed NMDA receptor-mediated transmission. The two former combinations had a subadditive effect on non-NMDA receptor-mediated transmission, and the latter had no significant effect. These studies identified that all combinations synergistically reduced both nociceptive transmission and potential side effects. In free-moving sheep implanted with indwelling cervical intrathecal catheters, 100 µ1 subdural administration of ketamine (25-400 µM) and ketoprofen (200-3200 µM) alone and in a fixed-ratio combination (873.95-3350.78 µM, 0.045:0.955) did not raise nociceptive thresholds as assessed by mechanical stimulation of one foreleg. Subdural administration of NMDA (2 mM) decreased mechanical nociceptive thresholds, and this was prevented by the highest concentrations of ketamine and ketoprofen alone and in combination. These findings demonstrated that NMDA receptor channel blockers and NSAIDs alone or in combination had no direct hypoalgesic effects when given onto the spinal cord of sheep, but they prevented NMDA-induced pain hypersensitivity. Simultaneous blockade of NMDA receptor systems could have important clinical implications.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 191-209).

Tez (Tıpta Uzmanlık) - Süleyman Demirel Üniversitesi, Tıp Fakültesi, Biyokimya Anabilim Dalı, 2006. / Bibliyografya var.