Background: One-third of men may experience biochemical failure by 8 years following radical radiotherapy for prostate cancer. Focal salvage therapy (FST) may offer further curative treatment. Before FST, distant disease must be ruled-out and intra-prostatic disease must be accurately detected and characterised. Aim: The aim of this thesis was to evaluate novel diagnostic and staging techniques and outcomes of focal salvage treatments for radiorecurrent prostate cancer. Methods: Both retrospective and prospective data will be presented. A retrospective analysis was conducted to compare a) Bone scan with Choline PET/CT in the detection of distant metastases b) Accuracy of MRI-Targeted Biopsy (MRI-TB) with whole-gland template mapping biopsy (TPM) c) the outcomes of focal salvage HIFU (FS-HIFU). These retrospective analyses provided important inputs into the design and conduct of the prospective trial FORECAST - Focal RECurrent Assessment and Salvage Treatment. Key trial outcomes were a) detection rate of distant metastatic disease of Whole Body MRI compared to other staging scans b) detection rate of MRI for clinically significant prostate cancer and c) Short-term outcomes of focal salvage therapies. Outcomes: Within the retrospective analyses, there was poor concordance with bone scan and Choline PET/CT in the detection of metastatic disease (kappa value 0.024). MRI-TB had lower detection rates of clinically significant cancer compared with TPM biopsy; 77.9% vs. 85.7% (p=0.146). The b-DFS rate post FS-HIFU was 48% (95% CI 39–59) and composite end free survival was 40% (95% CI 31–50). In the prospective analyses, there was moderate agreement between WB-MRI and Choline PET/CT for bony metastatic disease (Kappa=0.411 (p < 0.0001)). MRI (PIRADS 4) had a high sensitivity, specificity, PPV and NPV for the detection of clinically significant cancer 90%, 81.3%, 85.7% and 86.7%. b-DFS rates post FS-HIFU and FS-cryotherapy was 73% (95% CI 51-100) and 67% (95% CI 30-100) at 12 months (p=0.95).

Tribocorrosion at the taper junctions of femoral components in total hip arthroplasty is a complex mechanism and a source of metal release in the body. Understanding the various modes and mechanisms of in-vivo corrosion and the pathogenesis of the body’s biological response that results in implant failure is of significant clinical importance. This thesis focused on the forensic analysis, using both metrology methods and synchrotron radiation, of a class of modular orthopaedic implants - dual-taper hip arthroplasty, retrieved from patients whose hip replacements were revised secondary to adverse reaction to metal debris (ARMD). Emphasis was placed on the forensic investigation of the neck/stem junction of contemporary designs and the recalled Rejuvenate modular femoral stem. All the retrieved implants in the CoCr/Ti combination group showed moderate to severe corrosive attack. The severity of taper degradation was found to increase with implant time in situ and to be associated with a greater Co to Cr ion ratio in the blood. Metal species identified in periprosthetic tissue from these corroded implants, were analysed for metal distribution and oxidation state by means of synchrotron radiation. For the first time, Ti was found in an amorphous dioxide form and Cr in Cr2O3. The metal species showed preferential affinity between each other and were often co-localized. This suggests that the complexity (in morphology and chemistry) of the debris may play an active role in eliciting a pathologic response in periprosthetic tissues. The findings from this body of research will inform future toxicological studies and may provide useful information helping to better design future pre-marketing tests of orthopaedic implants and more broadly the understanding of the metal/metal and metal/body interactions.

No description available.

The ability to isolate specific cells from a heterogeneous population using label-free methods, and subsequently extract these cells at high throughput, is a key step in the advancement of autologous cell-based therapies in the field of regenerative medicine. Surface acoustic wave-based dielectrophoresis (SAW-DEP) utilises a standing shear horizontal SAW to provide a non-uniform electric field in which cells can be separated by dielectrophoresis. Due to the absence of electrodes in contact with the solution, this method overcomes many disadvantages of current dielectrophoretic technologies, allowing cell separation at high continuous throughput (< 500 cells/second) and in high conductivity solutions (< 0.4 S/m). This thesis describes the design and application of several iterations of SAW-DEP devices. After demonstrating the alignment of latex beads (1 - 10 μm) by negative DEP, the force exerted on latex beads is studied by particle tracking, and is shown to closely match a theoretical model for dielectrophoretic trapping. Following this, the separation of viable from non-viable yeast cells and mammalian cells is demonstrated. To ascertain whether SAW-DEP has any adverse effect on cells, primary human mesenchymal stromal cells (dental pulp stromal cells) are tested for viability and differentiation capability following exposure to the SAW-DEP electric field, with the results showing that the electric field had no effect, compared to controls where the cells were not exposed to the electric field. Finally, the ability to tune the liquid conductivity is investigated as a means to separate live from dead mammalian cells to high fidelity (live and dead cells were enriched into lines of 97% and 99% purity, respectively), as well as separating live mammalian cells of different lineages.

Introduction: A complex two-way link between periodontitis and diabetes is widely accepted. Although the mechanisms underlying this link have not been fully elucidated, disruption of host immunity (neutrophil function, cytokine release), tissue biochemistry, accumulation of advanced glycation end products (AGEs), matrix metalloproteases (MMPs) levels and the oral microbiota have been implicated. Aims and objectives: This project aims to investigate potential mechanisms through analysis of the impact of AGEs (a consequence of hyperglycaemia), on biofilm composition and telomerase immortalised gingival keratinocytes (TIGK). In addition, presented here is a preliminary feasibility study for comparison of oral biofilm composition and functionality, neutrophil function, and saliva and gingival crevicular fluid (GCF) cytokine and MMP profiles from healthy and periodontitis individuals. Methods: The study characterised receptor for AGE (RAGE) expression in TIGK cells and the consequent immune response initiated by AGE/RAGE interactions in these cells. Model oral biofilms (comprising five periodontal species) grown in the presence and absence of AGE were characterised using culture dependent methods. Complex biofilms, derived from combined saliva/tongue/plaque inocula, grown with AGE concentrations representative of hyperglycaemia or health were analysed using next generation sequencing. In a preliminary study, biofilms were also co-cultured with TIGK cells in media supplemented with high AGE concentrations to determine changes in inflammatory responses. Individuals with periodontitis and healthy controls were recruited through DenTCRU for the preliminary clinical study. Neutrophil migration, phagocytosis and respiratory burst in these individuals were analysed. Plaque, GCF and saliva were collected for analysis of cytokine and MMP expression and oral microbiome profiles. Results: The expression of RAGE by TIGK cells, at either the mRNA or protein level, did not change with varying concentrations of AGE. The addition of AGE to model five species biofilms encouraged the growth of A. naeslundii while reducing the proportion of P. gingivalis in the biofilms. Analysis of complex biofilms indicated enrichment of genera including Prevotella, Streptococcus and Veillonella and decreases in Fusobacterium, Campylobacter and Bacteroides amongst others. The preliminary clinical study indicated feasibility of analysing neutrophil function and cytokine and MMP profiles from saliva and GCF. While impairment of neutrophil functions, increase in MMP8 and MMP9, changes in biofilm compositions and increases in cytokines in saliva (IL-8, IL-1β and MCP-1), plasma (IL-8 and IL-1β) and GCF (IL-8,IL-1β and MCP-1) were observed in periodontitis, further analysis using a larger cohort of individual’s ± periodontitis is required for these to reach significance. Conclusion: Together the results suggest AGEs can alter the composition of biofilms, appearing to encourage the growth of health associated genera. Preliminary co-culture experiments demonstrate co-culture of TIGK cells with complex biofilms decreases IL-8 and IL-6 release.

Porous strontium-doped apatite-wollastonite scaffolds were evaluated as potential substitutes for enhanced bone regeneration and the prevention of peri-prosthetic infections. Parent glasses of composition 35.5SiO2-7.1MgO-0.4CaF2-7.1P2O5-(49.9-x)CaO-xSrO mol%, where x = 0, 6.2, 12.5, 18.7, 24.9 or 37.4, were produced via the melt-quench route, ground and sieved < 45 μm. Porous scaffolds were obtained following the foam-replication method and heat-treated at 1050 °C for 2 h for controlled nucleation and growth of the crystal phases. All six glasses produced were amorphous. Differential scanning calorimetry showed that the formation of the calcium silicate phase strongly depended on the amount of strontium contained in the parent glass, linearly moving to higher temperatures with increasing strontium. Morphological evaluation (scanning electron microscopy and micro-computed tomography) proved that the obtained scaffold porosity, about 55 vol%, did not depend on the strontium content. X-ray diffraction showed that strontium preferentially substituted in apatite, while only higher strontium compositions formed a strontium magnesium calcium silicate phase. Compressive and biaxial flexural strength were both comparable to cancellous bone. Compositions containing 0 %, 6.2 % and 12.5 % strontium showed excellent apatite forming ability when submerged in simulated body fluid, which then decreased with increasing strontium for the three higher-strontium compositions. Microbiological tests carried out on strontium-containing salts showed no effective antibacterial properties for strontium as a free element. Amongst the six strontium-containing glasses, only the 37.4 % strontium oxide glass showed antimicrobial effects against Pseudomonas aeruginosa in broth dilution tests. Proliferation and osteogenic differentiation of porous scaffolds were tested on human bone cells. No conclusive results were obtained for the G292 cell line. When scaffolds were tested with human primary mesenchymal stromal cells, an increase in DNA content was observed with increasing strontium, while enhanced alkaline phosphatase activity and increased collagen production were found for low strontium compositions.

No description available.

No description available.

No description available.

Massive endoprostheses are used for the reconstruction of bone defects following removal of malignant bone tumours. Aseptic loosening is a major cause of failure of endoprostheses and accounts for 25% of revisions. The main hypothesis of this thesis was that a novel porous selective laser sintered (SLS) Ti6Al4V collar augmented with electrochemically deposited hydroxyapatite coatings will enhance osseointegration. A radiological study that evaluated the effect of chemotherapy on the osseointegration of massive endoprostheses in bone tumour patients showed significantly increased loosening at 3 years in patients who received chemotherapy and that osseointegration to the implant collar was protective against signs of radiographic loosening. This study highlighted the importance of increasing osseointegration of these implants. An experimental study investigated the osseointegration of SLS Ti6Al4V collars in an ovine midshaft implant over a 6 month period. SLS porous collars provided a greater area for bone contact (p < 0.001) and greater osseointegration (p < 0.001), with bone directly permeating into the porous structure. Electrochemically deposited hydroxyapatite (EHA), silicate-substituted hydroxyapatite (ESiHA) and strontium-substituted hydroxyapatite (ESrHA) were developed enabling the inner pores of SLS structure to be coated. ESiHA (1.63 Si wt%) and ESrHA (4.08 Sr wt%) coatings were optimised and both crystalline and amorphous phases were found with significant dissolution of Si from ESiHA (p=0.002). No significant differences were found when stem cell proliferation and osteogenic differentiation were compared between coatings. In an ovine defect model, investigation of these coatings on SLS implants of two different pose sizes (1125μm and 550μm) showed increased osseointegration with electrochemically coated implants (p < 0.001). Osseointegration was greatest with the EHA coating on the smaller pore size (p < 0.05). 2 In conclusion, the hypothesis can be accepted and novel electrochemically coated laser sintered porous collars may provide a viable alternative ingrowth region to enhance the osseointegration of massive bone tumour endoprostheses.