<p>The Application of Magnetic Resonance (MRI) and Computed Tomography Imaging (CT) in the Diagnosis and Management of Maxillofacial Tumours. For decades maxillofacial surgeons over the world have been frustrated by the high and often fatal recurrence of certain advanced jaw tumours. This study conclusively proves that Computed Tomography and especially Magnetic Resonance Imaging significantly decreases recurrence of Odontogenic Keratocyst and Ameloblastoma and allows surgical planning to avoid these recurrences.</p>

Bibliography: leaves 126-147 / xiv, 147 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Summary: Aims to develop reliable procedures for determining the genetic status of embryos derived by IVF procedures prior to implantation. Prenatal diagnosis allows pregnancy to be established using only acceptable embryos / Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 1994

Changes in the metabolic state of the brain can occur, for example, as a result of neuronal activity or in pathologies such as cancer. In these cases, an altered energy demand can lead to changes in neurochemical concentrations detectable using proton magnetic resonance spectroscopy (¹H-MRS). This thesis explores in vivo ¹H-MRS methods for detection of such changes in the healthy and diseased brain. Specifically, this thesis aims to develop methods with semi-LASER localisation, thereby minimising the negative effects of chemical shift displacement and field inhomogeneity on spectral acquisition. Firstly, a Hadamard-encoded semi-LASER method for simultaneous measurement from two regions was developed at 7 T. Slice profiles, with low chemical shift displacement and small amounts of signal overlap, were revealed in phantom and in vivo. This was then implemented in a study of neurochemical change during positive and negative blood oxygen level-dependent (BOLD) responses. Negative BOLD responses are thought to reflect regions of neuronal suppression. A small decrease in ascorbate, as well as the T2*-induced linebroadening of several spectra, were observed in these regions. Furthermore, increases in glutamate and lactate were detected in positive BOLD regions. These findings suggested that negative BOLD may not be generated by an increase in local GABA concentration. Secondly, an optimised semi-LASER sequence (TE = 110 ms) at 3 T was shown to improve localisation of the oncometabolite 2-hydroxyglutarate (2-HG) - a product of IDH-mutation found in the majority of gliomas. This resulted in improved detection of 2-HG in patients compared to an existing technique. The method was also compared to 7 T, where benefits of an increased spectral resolution resulted in significantly better detection of 2-HG along with associated metabolites. This thesis highlights the importance of robust localisation for performing sensitive in vivo ¹H-MRS neurochemical measurement in the human brain.

Thesis (MTech (Biomedical Technology))--Cape Peninsula University of Technology, 2012. / Oxidative stress, in recent times appears to be a major underlying risk factor in the occurrence of various diseases such as cardiovascular disease (CVD) and ischemic heart disease (IHD). During oxidative stress, there is an imbalance between the production of reactive oxygen species (ROS) and antioxidant defence mechanisms in favour of ROS. This results in severe cellular damages in the heart, vascular membranes and other organs. Potential benefits of dietary supplements as one of the major quenching elements against oxidative stress have been highlighted. Thus, a growing interest has been stimulated in finding natural alternatives for the treatment and! or prevention of oxidative stress-mediated diseases. Red palm oil (RPO), refined from the tropical plant Elaeis guineensis was used in this study since it has captivated much attention in the health sector lately. The effects of RPO-supplementation on oxidative stress biomarkers as well as homocysteine, a cardiovascular disease risk factor in an oxidative stress-induced rat model were investigated in this in vivo study. All experiments were conducted for a period of six weeks. Male Wistar rats (120-150g) were randomly divided into six groups (n=5) where all the rats received a standard diet. Two groups (groups C, D) were supplemented with 0.175g RPO (7g RPO/kg chow) for four weeks whereas groups (groups E, F) were given 0.175g RPO (7g RPO/kg chow) supplementation for six weeks. Rats in control groups (groups A, B) were not given any RPO-supplementation. Groups B, 0, F were induced with oxidative stress by injection of 0.5ml (20IlM/100g of body weight) organic tertiary-butyl hydroperoxide. All parameters were determined using appropriate methods in plasma, serum and erythrocytes. Data were expressed as mean ± SEM. No significant differences were obtained between groups for total antioxidant capacity and glutathione peroxidase activity. Red palm oil supplementation significantly increased superoxide dismutase activity after 6 weeks consumption, total glutathione levels after 4 weeks consumption and homocysteine levels after four and six weeks consumption in rats not subjected to oxidative stress. Under oxidative stress conditions, malondialdehyde (MOA) level, a marker of oxidative stress related damage, significantly increased in rats receiving a standard diet. However, when RPO diet was supplemented for 4 and 6 weeks, MOA levels significantly decreased towards the value of normal controls. In conclusion, our findings suggest that RPO-supplementation could ameliorate antioxidant status in the body through its potential ability to increase some antioxidant enzymes activity. Similarly, it is suggested that RPO-supplementation could protect the rat against oxidative stress induced damage in diseased state.

Nanoparticles has drawn attention in the past few decades for their large surface area-to-volume ratio, unique optical property, fast mass transportation and etc. They are widely applied in biomedical field as they are excellent signal transducers. Among all detection approaches, fluorescence detection, especially fluorescence resonance energy transfer (FRET), is one of the most popular approaches for their great convenience. In the first detection scheme, a well-designed nanoprobe was utilized for direct trypsin quantification. Herein, a graphene quantum dot (GQD) applied as a donor while a coumarin derivative, CMR2, acted as an acceptor. Moreover, bovine serum albumin (BSA), as a protein model, was not only considered as a linker for the donor-acceptor pair, but also a fluorescence enhancer of the quantum dots and CMR2. In the presence of trypsin, BSA was digested, thus, the FRET system was destroyed. Consequently, the emission peak of the donor was regenerated while the emission of the acceptor was reduced. The trypsin was quantified by a ratiometric measurement for two emission peaks. The detection limit of trypsin was 0.7 g/mL, which is 0.008-fold of the average trypsin level in acute pancreatitis patient's urine. Moreover, the approach was proved to be highly selective, suggesting a high potential for fast and low cost clinical screening. On the other hand, the optical property of nanoparticle has captured a great attention as its light scattering is highly sensitive to local dielectric environment. Two light scattering based detection approaches were demonstrated, including simple counting method and plasmonic scattering enhancement method. For simple counting method, antibody modified nanoparticle was applied to target antigen, providing a sensitive but direct approach for cancer biomarkers quantification. As a proof of concept, prostate-specific antigen (PSA) was chosen as an example. Antibody-conjugated silver nanoparticles (AgNP-Ab) were served as the probe to capture PSA, forming AgNP-Ab-PSA complexes. Since the number of complexes was corresponding to the amount of PSA, the antigen was quantified by counting the number of silver nanoparticle under dark field microscopy (DFM) coupled with charge-coupled device (CCD) camera. The detection limit of 9 pM of this assay was well below the PSA threshold of prostate cancer patient, suggested the feasibility of our assay in diagnosis application. Besides counting of nanoparticle, the scattering intensity of nanoparticle is also informative. In the third assay, immobilized capture antibody-conjugated gold nanoparticles (AuNP-Abcapture) were firstly utilized in capturing the target analyte, followed by the introduction of strong scattering detection antibody-conjugated silver nanoparticles (AgNP-Abdetection). In the presence of the corresponding antigen, the two metallic probes sandwiched the antigen and stayed at close proximity, resulting a strong plasmonic coupling effect of those nanoparticles. Consequently, the scattering intensity of gold nanoprobe was greatly enhanced. The antigen was quantified by measuring the intensity change before and after the immunoreaction. To demonstrate the high flexibility of this assay, several antigens including carcinoembryonic antigen (CEA), PSA and alpha fetoprotein (AFP) were quantified with this method, giving detection limit at 1.7 pM, 3.3 pM and 5.9 pM respectively, which were much lower than their cut-off levels of corresponding diseases. Detections of CEA, PSA and AFP in real sample were demonstrated, suggesting a high potential in clinical application.

No description available.

Pancreatic ductal adenocarcinoma (PDAC) has the poorest five-year survival rate of any cancer. Currently, there are no effective diagnostics or chemotherapeutics. Surgical resection is the only curative therapy. However, most patients experience recurrence due largely to challenges in assessing tumor margin status in the operating room. Molecular probes that selectively highlight pancreatic cancer tissue, having the potential to improve PDAC margin assessment intraoperatively, are urgently needed. In this work, a series of red and near-infrared fluorescent probes is reported. Two were found to distribute to normal pancreas following systemic administration. One selectively accumulates in genetically modified mouse models of PDAC, providing cancer-specific fluorescence. In contrast to the small molecule probes reported previously, it possesses inherent affinity for PDAC cells and tissue, and thus does not require conjugation to targeting agents. Moreover, the probe exhibits intracellular accumulation and enables visualization of four levels of structure including the whole organ, tissue, individual cells and subcellular organelles. It can thus promote new strategies for precision image-guided surgery, pancreatic cancer detection, the monitoring of therapeutic outcomes and basic research.

Human cytomegalovirus (HCMV) infection is the major cause of illness and death in immunocompromised patients. HCMV is the most common cause of congenital viral infection in humans. A polymerase chain reaction (PCR) method was developed for the rapid detection of CMV in urine. Several parameters of the PCR procedure were optimized to reduce time and improve sensitivity. By eliminating the extraction of DNA from clinical specimens, reducing the number of amplification cycles, utilization of the "hot start" PCR procedure and direct detection of PCR product by ethidium bromide fluorescence staining, a procedure was developed which could be performed in less than 3 hours. Comparison studies using cell culture and direct detection of CMV by PCR on urine specimens were performed. Sensitivity was further examined to determine if inhibitors of the PCR reaction were present in urine.

The potential use of four radioiodinated fatty acids as myocardial imaging agents were evaluated. Preliminary distribution studies revealed that the terminal labeled fatty acids demonstrated higher myocardial uptake. Thus, 10-Iodocapric acid (10-iododecanoic) and 12-Iodolauric acid were subjected to further investigation. Comprehensive tissue distribution studies involving both radioiodinated fatty acids in mice indicated that the highest accumulation of the total injected activity occurred in the muscle and the blood. Other organs investigated included the heart, liver, lung, kidneys, spleen, stomach, intestines, bone and adrenals. The heart exhibited the highest concentration of the radioiodinated fatty acids for the relative accumulation of activity per unit weight. Erom the tissue distribution studies, the optimum scanning time was found to be immediately following injection of the radiopharmaceutical. Toxicity studies were performed in mice after intravenous administration of 10-Bromocapric acid and 12-Bromolauric acid. The LD₅₀ of Sodium Bromolaurate in 10% Human Serum Albumin was found to be 210 mg/kg (194 mg/kg - 228 mg/kg). The stability problem encountered with 10-Bromocapric acid necessitated the use of a different solvent system. The LD₅₀ obtained after intravenous injection was found to be 86.1 mg/kg (83.0 mg/kg - 89.3 mg/kg). However, this observed toxicity may not necessarily reflect the toxicity of the Bromocapric acid solely. Whole body excretion studies were performed in mice and revealed a triexponential excretion curve. For 10-Iodocapric acid, the effective half-lives were .90 hours (36.7%), 3.91 hours (61.6%) and 74.9 hours (14.5%). For 12-Iodolauric acid, the effective half-lives were 1.67 hours (46.6%), 7.68 hours (38.4%), and 71.6 hours (17.8%). For both 10-Iodocapric acid and 12-Iodolauric acid, the first as well as the second component of the excretion curve presumably represented a decrease in the whole body activity due mainly to urinary excretion. The third component appeared to represent activity which was tightly bound and slowly released. The third component presumably represented elimination by fecal excretion. The excretion of the injected activity was primarily in the urine, although some activity was recovered in the feces. For 10-Iodocapric acid, 82.4% of the injected activity had been recovered in the urine within the first 24 hours and 8.88% had been recovered in the feces. For 12-Iodolauric acid, 78.9% of the injected dose was recovered in the urine at 24 hours and 9.4% in the feces. From the urine results, the effective half-life of the radio-iodinated fatty acids in the kidneys was found to be 4.8 hours. Myocardial scans were done on rabbits using ¹³¹I-capric acid, ¹³¹I-lauric acid, NaI-131 (6% Human Serum Albumin), and Thallium-201 at specified time intervals after injection. Iodine-123, a radionuclide possessing more favorable imaging properties, was not readily available due to production problems at the time of scanning. The mean absorbed dose to the whole body, the liver, the kidneys, the muscle, and the heart were computed based on the results from the distribution and excretion studies. The dosimetry calculations were done using Iodine-123 as the radionuclide. For ¹³¹I-capric acid, the radiation doses were calculated as 34.76 mrads/2 mCi for the whole body, 136.3 mrads/2 mCi for the kidneys, 86.6 mrads/2 mCi for the liver, 38.5 mrads/2 mCi for the muscle, and 25.89 mrads/2 mCi for the heart. For ¹³¹I-lauric acid, the radiation doses were 41.73 mrads/2 mCi for the whole body, 199.8 mrads/2 mCi for the kidneys, 185.9 mrads/2 mCi for the liver, 52.07 mrads/2 mCi for the muscle, and 46.39 mrads/2 mCi for the heart. / Pharmaceutical Sciences, Faculty of / Unknown

This thesis presents a novel ZnO-hydrogel based fluorescent colloidal semiconductor nanomaterial system for potential bio-medical applications such as bio-imaging, cancer detection and therapy. The preparation of ZnO nanoparticles and their surface modification to make a biocompatible material with enhanced optical properties is discussed. High quality ZnO nanoparticles with UV band edge emission are prepared using gas evaporation method. Semiconductor materials including ZnO are insoluble in water. Since biological applications require water soluble nanomaterials, ZnO nanoparticles are first dispersed in water by ball milling method, and their aqueous stability and fluorescence properties are enhanced by incorporating them in bio-compatible poly N-isopropylacrylamide (PNIPAM) based hydrogel polymer matrix. The optical properties of ZnO-hydrogel colloidal dispersion versus ZnO-Water dispersion were analyzed. The optical characterization using photoluminescence spectroscopy indicates approximately 10 times enhancement of fluorescence in ZnO-hydrogel colloidal system compared to ZnO-water system. Ultrafast time resolved measurement demonstrates dominant exciton recombination process in ZnO-hydrogel system compared to ZnO-water system, confirming the surface modification of ZnO nanoparticles by hydrogel polymer matrix. The surface modification of ZnO nanoparticles by hydrogel induce more scattering centers per unit area of cross-section, and hence increase the luminescence from the ZnO-gel samples due to multiple path excitations. Furthermore, surface modification of ZnO by hydrogel increases the radiative efficiency of this hybrid colloidal material system thereby contributing to enhanced emission.