Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease and is characterized by progressive paralysis leading to death, typically, within 3-5 years of the onset of symptoms. The majority of ALS cases are sporadic with no known causative agent; however, 5-10% of ALS cases are genetically inherited and termed familial ALS (fALS). Approximately, 15-20% of these fALS cases have been linked to mutations in the gene encoding human Cu/Zn superoxide dismutase (hSOD). To date, over 140 hSOD mutations have been discovered. The mechanisms by which mutant hSOD confers toxicity in fALS patients are still unknown. However, there is growing evidence that ALS is a type of protein conformational disease whereby cell damage or death is caused by the accumulation of protein aggregates in the cell. It is hypothesized that mutations destabilise hSOD and increase its propensity to aggregate. There is some controversy as to which hSOD species contributes to aggregation. Many believe that only apo or mismetallated forms of hSOD are able to aggregate. Due to the abundance of fully metallated or holo hSOD in the cell, we hypothesize that holo hSOD can also lead to aggregation. Holo dimer interface mutants A4S, A4T and I113T as well as G41D were found to be destabilized compared to holo pseudo wildtype (pWT) while zinc binding mutant H80R was shown to form fragments via an unknown mechanism. Holo dimer interface mutants A4S and A4T were also shown to have an increased propensity to aggregate compared to pWT, which correlates to their decreased stability as well a short disease durations.

Aging is associated impaired endothelial function in the skeletal muscle vasculature which contributes to decreased ability to increase muscle blow during exercise. This endothelial dysfunction is mediated, primarily, by impairments in the nitric oxide (NO) pathway in the skeletal muscle vasculature. The major purpose of this dissertation is to determine the mechanisms that mediate age-related endothelial dysfunction in rat soleus feed artery (SFA) and determine whether exercise training ameliorates this impairment in endothelial function. Therefore in these series of studies we sought to test three major hypotheses: 1) That exercise training reverses age-related decrements in endothelium-dependent dilation in SFA and that this improved endothelium-dependent dilation is the result of increased NO bioavailability due to increased content and phosphorylation of eNOS and/or increased antioxidant enzyme content; 2) That age-related endothelial dysfunction in rat SFA is mediated in part, by NAD(P)H oxidase-derived reactive oxygen species (ROS); 3) and, that impaired endothelium-dependent dilation in senescent SFA is due to an impaired potential for p-eNOSser1177. To test these hypotheses, SFA from young (4 month) and old (24 month) Fischer 344 rats were isolated for either determination of endothelium-dependent and –independent dilations or biochemical analyses. Results from these investigations suggest that 1) exercise training reverses the detrimental effects of aging on endothelial function in skeletal muscle feed arteries by enhancing the capacity to scavenge superoxide, increasing the bioavailability of NO; 2) ROS contribute to impaired endothelium-dependent dilation in old SFA; whereas, ROS appear to play a role in ACh-mediated dilation in SFA from young rats; 3) and, that the PI3 kinase/protein kinase B (Akt)/eNOS pathway is preserved with age.

No description available.

Calcium (Ca$ sp{2+}$) and protein kinase C (PKC) are believed to act as intracellular signals triggering the activation of NADPH oxidase in neutrophils leading to superoxide generation. This was tested on bovine neutrophils by chelating extracellular and/or intracellular free Ca$ sp{2+}$ and by measuring PKC activity when the cells were stimulated by phorbol myristate acetate (PMA) or opsonized zymosan (OZ). Chelation of extracellular Ca$ sp{2+}$ with EGTA did not alter O$ sb2 sp{-}$ production from PMA stimulated cells. However, it did cause a 64% decrease in O$ sb2 sp{-}$ production in the neutrophils when stimulated with OZ. When intracellular Ca$ sp{2+}$ was chelated with BAPTA/AM, there was a significant decrease in O$ sb2 sp{-}$ generation following PMA activation. Yet, OZ activated cells, pre-treated with BAPTA/AM, showed an increase in the respiratory burst proportional to the chelator's concentration. Moreover, although OZ was previously shown to increase O$ sb2 sp{-}$ generation by neutrophils, no significant changes in PKC activity were observed. PMA stimulation led to an increase in PKC activity at the membrane level. Furthermore, treating the cells with calphostin C, a PKC activity inhibitor, caused a 69% decrease in O$ sb2 sp{-}$ production demonstrating the involvement of PKC in PMA-stimulated cells. However, no differences were observed between the OZ activated cells incubated with the inhibitor and the control cells. These data provide evidence that activation of NADPH oxidase can be achieved by either a PKC-dependent or a PKC-independent pathway depending on the stimulatory agent.

Thesis (M.D.)--University of Adelaide, Dept. of Medicine and Pathology, 1985. / Includes bibliographical references (leaves 161-204).

Diss. (sammanfattning) Umeå : Univ., 2004. / Härtill 4 uppsatser.

Thesis (Ph. D.)--Cornell University, August, 2008. / Vita. Includes bibliographical references (leaves 131-153).

Dissertation (Ph.D.).--University of Texas Graduate School of Biomedical Sciences at San Antonio, 2008. / Vita. Includes bibliographical references.

Thesis (Ph.D.). / Written for the Dept. of Neurological Sciences. Title from title page of PDF (viewed 2009/06/11). Includes bibliographical references.

Th.--Pharm.--Paris-Sud, 1985. / Bibliogr. p. 189-215.