"October 2001" Amendments (4 leaves) inserted inside back cover. Includes bibliographical references (leaves 215-266)

Background and objectives: The most widely accepted tooth movement model is defined by the pressure-tension hypothesis. An orthodontic force applied to a tooth generates areas of compression and tension in the periodontal ligament (PDL), which are transmitted to the alveolar bone. Areas of tissue exposed to tensile strain undergo bone deposition, whereas areas of tissue exposed to compressive strain undergo bone resorption. We propose that human PDL cells in monolayer culture exposed to tensile mechanical strain would express multiple genes involved in osteogenesis. Materials and Methods: Human PDL cells were isolated and cultured from premolar teeth that were extracted for orthodontic reasons. These cells were plated on control and experimental Uniflex[TM] plates. Using a Flexercell FX4000 strain unit, PDL cells on experimental plates were exposed to a 12% uni-axial cyclic strain for 6 seconds out of every 90 seconds over a 24 hour period. RNA was extracted from the PDL cells at 6 hours, 12 hours and 24 hours. The differential expression of 78 genes implicated in osteoblast differentiation and bone metabolism was analysed using real-time reverse transcriptase polymerase chain reaction (RT-PCR) array technology. Results: Of the 78 genes tested, sixteen genes showed statistically significant (p<0.05) changes in expression in response to the mechanical strain regime. Eight genes were up-regulated (ALPL, BMP2, BMP6, COL2A1, ICAM1, PHEX, SOX9, and VEGFA) and eight genes were down-regulated (ANXA5, BMP4, COL11A1, COL3A1, EGF, ITGB1, MSX and SMAD1). Conclusions: This study has demonstrated that cultured human PDL cells express multiple osteogenic genes under tensile strain, which suggests that PDL cells may have a potential role in osseous remodeling during tooth movement. Key Words: Tooth movement, human PDL cells, tensile mechanical strain, osteogenic genes, real-time RT-PCR array, and Flexercell FX4000.

Journal article co-authored by the author inserted at end (Plant pathology (1991) 40, 67-77) / Includes bibliographical references (leaves 124-167) / xxv, 167 leaves : ill., plates ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Describes the isolation of antibody and DNA probes which vary in their reaction to different anastomosis groups of Rhizoctonia solani. Evidence is presented to show that isolates from anastomosis group 8 are biochemically distinct from isolates in other anastomosis groups found in South Australia. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences, 1992

"March 2002" / Addendum inserted at back. / Includes bibliographical aspects (leaves 105-117) / xi, 117 leaves : ill. (some col.), plates (col.) ; 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 Molecular Biosciences, 2002

"May 2002" / Bibliography: leaves 160-171. / xi, 189 leaves : ill. (some col.), plates (some col.) ; 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 Applied and Molecular Ecology, 2002

Bibliography: leaves 96-104.

"February 1977." Includes bibliographical references (leaves [105]-[120]) The malignant transformation, and the relevance of developmental antigens to the cancer process, is broadly reviewed. The two developmental antigens - foetal and placental - are then examined in experimental mouse and rat tumour systems.

A unique tumor targeted method, which may be able to deliver a molecule to the surface of a tumor cell using the pH gradient between hypoxic tumor cells and normal tissue has recently been developed. Since solid tumors have been found to have a lower extra cellular pH compared to normal tissue (6.5 to 6.9 for tumors verses an average 7.4 for normal tissue), the pH gradient is used as a source of power to activate a strategically designed "molecular engine" capable of delivering a diagnostic or therapeutic agent to tumor cells. To test this hypothesis, a 22- sequence amino acid, which reorganizes to alpha helical form at pH 6.9 causing the molecule to become lipophilic and embed into the plasma membrane of nearby cells was synthesized. The molecule was then attached to 99mTc via a MAG-3 chelating molecule. In-vivo nuclear imaging was performed and showed apparent significant uptake in primary tumors as well as lung and liver in Lewis lung cell model C57blk-J6 mice with confirmed primary tumors at the base of the tail or lungs. This study shows significant promise for early diagnosis and treatment of cancer on a molecular level. / Graduation date: 2006

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

published_or_final_version / Anatomy / Master / Master of Philosophy