Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / Rhinosinusitis is a common condition that is chronic in up to 18% of the general population. If intensive medical treatment fails, then surgery may be required. Currently the accepted form of surgery is endoscopic sinus surgery. This technique involves opening the natural ostia of the sinuses to restore aeration and mucociliary drainage. The most frequent complication of this surgery is the development of postoperative adhesions. Their formation represents a failure of the healing process. To prevent the formation of adhesions, nasal packing is often used. To date the effect of nasal packing on the healing process has not been studied with rigorous scientific control. The sheep has been chosen as the most suitable animal model to investigate the healing process. The sheep is suitable in terms of size, histology, physiology, and pathology. The sheep's nasal cavity is also suitable for nasal endoscopy and surgery. Research conducted previously in the sheep model has demonstrated that unpacked full-thickness wounds take longer than three months to heal. The research in this thesis sought to determine if the use of different packing materials influenced healing. This thesis has compared the healing process that follows the use of three different nasal packing materials. These are a polyvinyl acetate based pack, a hyaluronic acid-based pack, and the hyaluronic acid-based pack with Insulin-like growth factor-I incorporated into it. Assessment was made using light microscopy, immunofluorescence, and electron microscopy. The results demonstrate that the use of a polyvinyl acetate sponge a dissolvable hyaluronic acid based pack confers no significant benefit to the healing process when compared to controls. However, the incorporation of insulin-like growth factor-I into the hyaluronic acid based pack resulted in a statistically significant (p<O,05) improvement in re-epithelialisation at day 28 (89% for Insulin-like growth factor-I versus 44% for controls). Attempts to assess the effect of this pack on the rate of adhesion formation was unsuccessful due to the inability to produce a replicable animal model of adhesion formation. It is concluded that the use of Insulin-like growth factor-I in the hyaluronic acid based packs confers an important benefit to the healing process after full-thickness injury. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1218836 / Thesis (Ph.D.) -- University of Adelaide, Medical School, 2005

The monitoring of fetal lambs in-vivo, has been previously carried out by using hard-wires. This work presents an alternative method for monitoring, by use of radiofrequency biotelemetry, with which there are no hard wires. With biotelemetry, a more "natural" recording may take place from the fetus. Long term, natural monitoring of fetal development has not been possible in the past.The design and implementation of a system capable of providing continuous, isolated monitoring is presented. The problems associated with the development and subsequent use of this system will be presented, especially the problem of noise.Data acquisition and analysis methods are also introduced and developed to suit the large amounts of information produced by the biotelemetry system.Analysed data from two fetal animals are presented and the significance of the reduced information is discussed.

Doctor of Philosophy(PhD) / This study was conducted to provide accurate information about the impact of OJD on sheep mortality and financial status on infected farms in Australia. Industry considered this research to be important because little credible information was available regarding the magnitude of the OJD problem and the responses required to control and manage OJD in southern Australia. This 3-year study, conducted on 12 OJD-infected farms in southern NSW, commenced with a 12-month observational study in 2002. During this year OJD mortality estimates were derived from farm records (livestock inventories) and quarterly farm visits (necropsy inspections). Questionnaires, climatic records and pasture samples enabled a detailed description of each farm to be made and a single collection of blood and faecal samples provided OJD prevalence information for specific age cohorts of sheep in each flock. The financial impact of OJD was established using two approaches, a gross margin analysis and the provision of a financial value on the mortalities inspected during the necropsy inspection periods. For a further 2 years, inventory and management information was collected from each of the twelve farms to provide 2003 and 2004 estimates for OJD mortality and financial loss due to OJD based on gross margin analyses. A more detailed gross margin model was developed that has the capacity to compare three disease status scenarios (uninfected, infected and vaccinated) for a number of different sheep production enterprises. These enterprises include fine, medium and strong wool Merino ewes and wethers as well as 1st and 2nd cross lamb production. From the four 5-day necropsy inspections conducted in 2002, a most likely cause of death was determined for 362 necropsied sheep on the basis of findings related to the environment, clinical signs, gross pathology and histopathology. Of these, OJD was most likely to have contributed to the death of 250 sheep, OJD was unlikely to have contributed to the death of 1 sheep and OJD did not contribute to death of 111 sheep. During 2002, across the 12 farms, there were a total of 52,718 wethers and 47,374 ewes at-risk of becoming infected with OJD. The distribution of mortalities in each sex group translates to an OJD mortality rate of 4.3% among wethers and 4.9% among ewes. Distribution across inspection periods showed a trend among OJD-related necropsies and total necropsies with the majority occurring in winter (31%) and spring (35%) and fewer in autumn (18%) and summer (16%). Across the 12 farms, the annual OJD mortality rate ranged from 1.8% to 17.5% during the 3-year study with mean annual figures of 6.2% in 2002, 7.8% in 2003 and 6.4% in 2004. Of concern is the fact that these mean OJD mortality figures were all above the accepted annual mortality rate from all causes for adult sheep of 4-6% (McGregor et al., 2003) for Australian flocks. Gross margins were calculated for each of the 12 farms assuming each farm was free of OJD and then these were compared with the actual farm gross margin. The mean percentage decrease in gross margin due to a farm being infected with OJD was 6.4% in 2002, 8.5% in 2003 and 7.4% in 2004. This equates to a mean reduction in annual income of $15,000 per farm in 2002, $12,154 in 2003 and $13,991 in 2004. Using the necropsy inspection information the mean estimated cost of OJD losses on the 12 farms over 2002 was $60,500 (range $10,978 to $150,836). The estimated cost of OJD losses accounted on average for 69.4% (range 19.4% to 100%) of the estimated total loss related to sheep deaths over the 12-month period. The OJD prevalence in 2-year old sheep in 2002 based on pooled faecal culture (PFC) ranged from 0.7% to > 23% on the 12 farms and was found to be associated with OJD mortality rate (P = 0.02). In contrast, no significant relationship was found between faecal excretion rate of MAP in two-year old sheep based on PFC and OJD mortality rate, or between age-related OJD seroprevalence and OJD mortality rate. The association between various environment, management and disease factors and quarterly OJD mortality rate was analysed and several factors (including flock size, stocking rate, area of improved pasture and weaning age) were identified as being important for further investigation. Definite conclusions based on statistical analysis could not be made due to the small number of farms and use of whole flock data. However, the results provide strong support for an additional study, involving a large number of farms and focusing on a specific sheep cohort, to identify the major risk factors for OJD. The necropsy study in 2002 established 31% of deaths were due to causes other than OJD and could have been prevented in most cases. More than half (63%) of the non-OJD deaths were attributed to malnutrition, with 57% of these deaths occurring on one farm where pregnancy toxaemia resulted from sheep receiving inadequate nutrition in late pregnancy. Many of these deaths could have been prevented with earlier feeding. The occurrence of grain poisoning on some farms reinforces the need for improved strategies when supplementary feeding. Under more favourable seasonal conditions these nutritional syndromes are unlikely to occur. Sporadic drought conditions throughout the 3-year study period, for each of the four study regions, were likely to have a minimal effect on measuring the impact of OJD on the 12 farms. At the end of 2002, following the realisation the drought would likely persist into 2003, the 12 farms on average selectively reduced flock numbers by 25%. However, this reduction is unlikely to have had an adverse effect on establishing the proportion of OJD mortalities as stock reductions occurred mainly towards the end of 2002 and the sheep most likely to be sampled at each necropsy inspection period were unlikely to be sold, as they displayed low body condition score and showed signs of weakness. A gross margin model was developed to provide an estimate of the on-farm cost of OJD. Non-infected, infected (status quo) and infected (vaccination) disease scenario examples were run for 1000 head Merino ewe and wether enterprises as well as first and second cross prime lamb enterprises. The total cost of OJD (relative to an uninfected status) and an avoidable cost of OJD (using GudairTM vaccination) were reported at four investment horizons to illustrate the cost of an OJD infection on a flock as well as the potential cost saving if a control strategy involving vaccination is implemented. Although vaccination reduces OJD mortalities, there is still an unavoidable cost incurred by the producer when compared to an uninfected flock. Results are presented as cumulative gross margin per dry sheep equivalent expressed in net present value terms (GM (NPV)/DSE) at 5, 10, 15 and 20-year intervals to enable a comparison between enterprises. The model suggests a vaccination breakeven point is achieved in two to three years for breeding enterprises if the level of OJD is high. If the level of OJD is low a vaccination breakeven point is achieved in three years for either a 1st cross or 2nd cross enterprise and seven years for a Merino ewe enterprise. The Merino ewe enterprises take the longest time to reach a vaccination breakeven point as more young sheep are retained annually for breeding in addition to the cost involved with vaccinating lambs, which is borne by all three breeding enterprises. The returns to vaccination are greatest for the 1st and 2nd cross lamb enterprises due to the value and number of lambs sold annually. With Merino wethers a vaccination breakeven point is reached in year one for all disease categories due to vaccinated replacement hoggets being introduced to provide an immediate response in reducing OJD mortalities, however as no breeding occurs the ability to increase income is limited. In the absence of OJD mortalities with the at-risk disease category, a vaccination breakeven point is not reached within the model’s 20-year time frame for any of the enterprises. This study provided the first objective data on the true impact of OJD on 12 farms, and the findings are generally applicable to sheep flocks in southern Australia. Industry groups claiming that OJD does not present a threat on-farm can now be provided with accurate figures on direct losses attributable to OJD within the endemic area of NSW. There was a wide range of impacts, with some very high mortality rates. The data can be used to justify vaccination programs, other control options and the general concept of disease control and prevention. The challenge now for industry is the design and implementation of an education and extension package that can incorporate these findings and the gross margin model along with other recent research findings to address issues of misinformation about OJD and inform producer decisions regarding on-farm disease control.

Nitric oxide (NO) alters chondrocyte metabolism, and is thought to be a key catabolic mediator in osteoarthritis. NO is also an important modifier of bone metabolism, and may partially mediate the bone-sparing effects of oestrogen. Oestrogen has also been linked to the modulation of osteoarthritis, though its role is not clear. The aim of this study was to examine the structural and metabolic effects of ovariectomy and the NO donor glyceryl trinitrate (GTN) on (1) normal ovine femoro-tibial joint tissues, and (2) the progression of joint lesions in the established ovine meniscectomy model of osteoarthritis. Preliminary investigations tested a novel computer-assisted histomorphometric method of assessing osteochondral changes post-meniscectomy, in a trial of a putative disease-modifying osteoarthritis compound. Quantitative assessment revealed a subtle protective effect not evident by qualitative methods. These techniques were then used to test the experimental hypotheses in a combined trial involving 48 aged ewes, variously subjected to ovariectomy, bilateral lateral meniscectomy, and/or topical GTN therapy. At six months, joint tissues were analysed using histology, histomorphometry, dynamic biomechanical testing, serum markers, bone densitometry, and tissue culture of synovial fibroblasts and explants of cartilage and bone. Ovariectomy modified cartilage structure and chondrocyte metabolism, and induced subchondral bone remodelling. Prior ovariectomy altered the development of OA lesions post-meniscectomy, producing thicker but biomechanically inferior cartilage and elevated metabolic activity in subchondral bone. GTN treatment of normal sheep induced thinner, structurally-altered cartilage in normal sheep, and accentuated cartilage and subchondral bone lesions post-meniscectomy. These results support an important homeostatic role for oestrogen in joint tissues, and show that GTN, a commonly used angina therapy, can induce structural alterations in joint tissues and potentially accelerate the progression of concurrent OA. Results also advance understanding of the role of synovial and subchondral bone changes in the pathogenesis of this OA model.

Thesis (M.S.)--Oregon State University, 1988. / Typescript (photocopy). Includes bibliographical references (leaves 87-94). Also available on the World Wide Web.

Thesis (M.S.)--Montana State University--Bozeman, 2008. / Typescript. Chairperson, Graduate Committee: Brett E. Olson. Includes bibliographical references (leaves 36-40).

Thesis (Ph. D.)--University of Adelaide, Dept. of Animal Sciences, Waite Agricultural Research Institute, 1987. / Includes bibliographical references (leaves 198-223).

Thesis (Ph. D.)--University of Adelaide, Dept. of Animal Sciences, 1986. / Includes bibliographical references (leaves 194-219).

Thesis (Ph. D.)--University of Adelaide, 1984. / Some ill. mounted. Includes bibliographical references (leaves [473]-504).

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed Apr. 29, 2008). PDF text: viii, 155 p. : ill. (some col.) ; 823 K. UMI publication number: AAT 3283914. Includes bibliographical references. Also available in microfilm and microfiche formats.