Trace elements are involved in many biological processes and serve important functions to maintain the normal development of the central nervous system (CNS). In the CNS, iron (Fe), copper (Cu), and zinc (Zn) are some of the most important elements that play critical roles as catalysts, cofactors, and structural components for many cellular enzymes and proteins. The deficiency or excess of these metals may lead to various neurological disorders. Demyelination is a condition of loss of myelin and leads to neurological diseases like Multiple Sclerosis. Myelin consists of transition metals and hence it would be interesting to study concentrations of these elements in normal and demyelinated models. X-Ray Fluorescence (XRF) is a popular non-destructive technique applied in trace element studies. The principle involves exciting a sample and detecting characteristic X-rays, which provide information on elemental concentrations in the sample. In the present studies the feasibility of XRF for trace element studies was explored. A total of 120 samples of brain and spinal cord tissues were collected from Long Evans (control) and Long Evans Shaker (dysmyelinated)–an incomplete formation of myelin sheaths–rats at ages of 3 weeks and 16 weeks. The samples were excited using x-rays from an Energy Dispersive X-Ray Diffraction (EDXRF) set-up. The spectral data was collected using an Silicon Drift Detector (SDD) and the resultant data were analysed to see if statistically significant changes in concentrations were present in the samples. The results were discussed and suggestions for future work were made. / Thesis / Master of Science (MSc)

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<p dir="ltr">Papilledema is the swelling of the optic disc resulting from increased cranial pressure. The diagnosis of papilledema is important not only to treat pathologies of the eye, but it also can be an important indicator for underlying brain pathology since the subarachnoid space surrounding the optic nerve is contiguous with the brain. Therefore increased pressure from the brain from pathologies such as hydrocephalus can be transmitted to the posterior eye. To study papilledema, a reproducible post hemorrhagic hydrocephalic rat model was used to study the changes of the retina, optic disc and optic nerve when exposed to high intracranial pressure. Multiple changes were noted in the post hemorrhagic hydrocephalic model including decreased thickness of the ganglion cell complex, decreased retinal thickness in the periphery in females, increased retinal thickness close to the optic nerve in males, increased optic disc width and diameter along with a decrease number of retinal ganglion cells. These findings were similar to findings in human patients with papilledema. Therefore, future studies are indicated using the post hemorrhagic hydrocephalic rat model to further understand the mechanism of papilledema progression and the use of possible therapeutics.</p>

The World Health Organization (WHO) estimates that one billion people worldwide suffer from central nervous system (CNS) disorders [1]. One major issue in treating these disorders is inadequate drug penetration which can be attributed to an effective blood-brain-barrier that limits passage across blood vessels. Low diffusivity of large classes of drug compounds restricts transport across blood vessel walls and subsequent passage through surrounding brain tissues. Tissue transport is emerging as an increasingly important area of research in drug delivery since the vast majority of therapeutic agents must traverse this space before reaching their targets.