Leung Kin Mei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 106-125). / Abstracts in English and Chinese. / Chapter CHAPTER 1 --- GENERAL INTRODUCTION --- p.1-11 / Chapter CHAPTER 2 --- ENZYMATIC REMOVAL OF CHONDROITIN SULFATES ABOLISHES THE AGE-RELATED ORDER IN THE OPTIC TRACT OF MOUSE EMBRYOS / INTRODUCTION --- p.12-13 / MATERIALS AND METHODS --- p.13-18 / RESULTS --- p.18-24 / DISCUSSION --- p.24-29 / FIGURES --- p.30-39 / Chapter CHAPTER 3 --- EXPRESSION OF PHOSPHACAN AND NEUROCAN IN THE DEVELOPING MOUSE RETINOFUGAL PATHWAY / INTRODUCTION --- p.40-42 / MATERIALS AND METHODS --- p.42-43 / RESULTS --- p.44-49 / DISCUSSION --- p.49-55 / FIGURES --- p.56-61 / Chapter CHAPTER 4 --- HEPARAN SULFATE PROTEOGLYCAN EXPRESSION IN THE OPTIC CHIASM OF MOUSE EMBRYOS / INTRODUCTION --- p.62-63 / MATERIALS AND METHODS --- p.63-65 / RESULTS --- p.66-70 / DISCUSSION --- p.70-76 / FIGURES --- p.77-82 / Chapter CHAPTER 5 --- EXPRESSION OF NEURAL CELL ADHESION MOLECULES IN THE CHIASM OF MOUSE EMBRYOS / INTRODUCTION --- p.83-85 / MATERIALS AND METHODS --- p.85-88 / RESULTS --- p.88-92 / DISCUSSION --- p.92.95 / FIGURES --- p.96-102 / Chapter CHAPTER 6 --- GERNEAL CONCLUSION --- p.103-105 / REFERENCES --- p.106-125

Thesis (Ph. D.)--Case Western Reserve University, 2004. / [School of Medicine] Department of Neurosciences. Includes bibliographical references. Available online via OhioLINK's ETD Center.

Though symptoms such as loss of vision, decline in cognition and memory are evident during aging, the underlying processes that affect neuronal function during aging are not well understood. Unlike changes in other tissues and organs, age-related changes in the nervous system affect the overall physical, mental as well as social state of human beings. To start elucidating the molecular mechanisms underlying normal age-dependent brain decline, we have characterized structural neuronal changes occurring during Caenorhabditis elegans aging. Our analysis reveals distinct neuronal alterations that arise with age and that the types of changes and their age of onset are neuronal-type specific, highlighting the differential susceptibility of neurons to the stresses of life. We also find that these age-dependent neuronal changes are largely uncoupled from lifespan. As a first step towards understanding the neuropathological conditions manifested during senescence, we have characterized the role of the neuronal maintenance gene sax-7/L1CAM in normal C. elegans aging. Our comparison of age-related structural changes in the wild-type nervous system with that of sax-7 mutants, indicates that loss of function of sax-7 results in accelerated neuronal deterioration that mimics alterations occurring during normal aging. Conversely, overexpressing wild-type copies of SAX-7 delays some of the neuronal changes that accompany normal aging, indicating that SAX-7 plays a neuroprotective role. Additionally we find that x mechanical stress from body movements impacts the neuronal changes during adulthood. Taken together, our results give an entry point into the mechanisms of age-related neuroanatomical changes and neuronal protection.