Recent advances in immunological technology have made it feasible to investigate the diagnosis and treatment of cancer with radiolabelled anti-tumor antibodies. The red bone marrow and endosteal cells of bone are likely to be the dose limiting tissues for systemic applications. Therefore, it is of clinical importance to quantitate their dose. Due to the small size of the marrow cavities in trabecular bone, it is experimentally difficult to measure the electron dose distribution. A computer simulation of electron transport is used to determine the dose distribution inside the marrow cavity. Electrons are backscattered more from bone than soft tissue, thereby increasing the dose to the radiosensitive endosteum and red bone marrow. A point source of beta activity (204Tl and 147pm) sandwiched between planar slabs of bone and red bone marrow equivalent plastics and 7LiF thermoluminescent dosimeters (TLD's) were used to determine the dose increase at various distances from the interface. Experimental results were compared with calculations using the Monte Carlo codes EGS (Electron Gamma Shower, SLAC) and CYLTRAN (Oak Ridge National Laboratory). The planar geometry was used as a benchmark geometry to compare the computer codes with experiment. After checking the accuracy of the codes for low energy electron transport, ACCEPT, a version of CYLTRAN, was used to investigate the radiation dose increase due to a point source of beta activity inside a polystyrene sphere bounded by aluminum. Spheres with radii of 200 and 500 microns were used. / Thesis / Master of Science (MS)

This thesis deals with the fixation of lower jaw with bone tissue defect using commercially produced fixator. Large defects of bone tissue are mainly caused due to the removal of bone tissue affected by tumor. These topics have been researched on the basis of the literature. Subsequently, stress strain analysis of the lower jaw with the applied fixation plate was performed. This analysis was solved by using computational modeling with variational approach, ie the finite element method. The work also describes in detail the procedure of creating model of geometry, model of material, model of boundary conditions and loads with subsequent solution of several computational models. The stress strain analysis was done for lower jaw with varying size of the removed bone tissue with applied reconstruction plate made of CP-Ti Grade 4 and for the lower jaw with the plate, which is made of -Ti-Mo. Finally, the influence of the mechanical properties of the callus during formation of new bone tissue (callus healing) on the stress and deformation of the solved system was evaluated.

Background: Multipotent mesenchymal stromal cells (MSC) can be recovered from a variety of tissues in the body. Yet, their functional properties were shown to vary depending on tissue origin. While MSC have emerged as a favoured cell type for tendon regenerative therapies, very little is known about the influence of the MSC source on their properties relevant to tendon regeneration. The aim of this study was to assess and compare the expression of tendon extracellular matrix proteins and tendon differentiation markers in MSC derived from different sources as well as in native tendon tissue. MSC isolated from equine bone marrow, adipose tissue, umbilical cord tissue, umbilical cord blood and tendon tissue were characterized and then subjected to mRNA analysis by real-time polymerase chain reaction. Results: MSC derived from adipose tissue displayed the highest expression of collagen 1A2, collagen 3A1 and decorin compared to MSC from all other sources and native tendon tissue (p < 0.01). Tenascin-C and scleraxis expressions were highest in MSC derived from cord blood compared to MSC derived from other sources, though both tenascin-C and scleraxis were expressed at significantly lower levels in all MSC compared to native tendon tissue (p < 0.01). Conclusions: These findings demonstrate that the MSC source impacts the cell properties relevant to tendon regeneration. Adipose derived MSC might be superior regarding their potential to positively influence tendon matrix reorganization.