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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Selenium Effects on the Trabecular Meshwork

Conley, Shannon Martha January 2005 (has links)
Epidemiological evidence indicates that selenium supplementation may increase risk for ocular hypertension and glaucoma. The purpose of this project was to determine the effects of selenium on the conventional "trabecular" aqueous outflow pathway, a likely site of pathology for glaucoma. Human trabecular meshwork (HTM) cells and human umbilical vein endothelial cells (HUVECs) were treated with selenium (MSeA) at or near physiologically relevant concentrations. Selenium uptake by cells was monitored using mass spectrometry. While detectible changes in intracellular selenium were observed after exposure to 1-10 uM MSeA for 24 hours, the majority remained in the conditioned medium. The high concentrations of extracellular selenium we observed raised the possibility that selenium has an extracellular target.To investigate the role of selenium in extracellular matrix turnover, I examined alterations in protein secretion and intracellular signaling. MSeA treatment (5-10 uM) led to a significant decrease in the secretion of matrix metalloproteinase -2 and its inhibitor after 6-24 hours and to a dose-dependent decrease in kinase signaling. Later, I investigated the possibility that integrins are an extracellular target of selenium by monitoring morphological changes in HTM cells and by treating them with divalent cations. MSeA stimulated morphological changes consistent with a decrease in integrin function. These occurred before (less than 3 hours) alterations in protein secretion and intracellular signaling (3-6 hours). Zinc treatment prevented MSeA-mediated alterations in protein secretion and changes in cell-matrix adhesion.Finally markers of HTM cell homeostasis were examined. MSeA treatment (5 uM) led to a 60% decrease in protein synthesis after 3 hours and a 60% reduction in protein secretion, without causing significant alterations in cell viability and total ATP. To assess the physiological relevance of my results, anterior segments were perfused with MSeA to determine its effects on aqueous outflow facility. Preliminary results suggest that MSeA leads to a decrease in outflow facility.The combination of MSeA-induced decreases in several indicators of HTM cell homeostasis (without adversely effects on cell viability at physiologically relevant doses) and decreases in outflow facility provide a possible mechanism for selenium-associated ocular hypertension.
272

High-speed optical packet switching over arbitrary physical topologies using the Manhattan Street Network

Komolafe, Olufemi O. January 2001 (has links)
No description available.
273

Residual stress measurement in engineering materials and structures using neutron diffraction

Dutta, Monojit January 1999 (has links)
No description available.
274

Matrix metalloproteinases in asthma : the role of mast cells and basophils

Rich, Kirsty January 1999 (has links)
No description available.
275

Quantification of the effects of reinforcement distribution and morphology on fatigue in Al-SiC←p composites

Boselli, Julien January 1999 (has links)
No description available.
276

Density of states in finite normal-superconducting structures

Maliehe, Nkhatamele B. January 1999 (has links)
No description available.
277

Invasive varactor tuning of a dielectric resonator

Fox, Andrew John January 1997 (has links)
No description available.
278

A modified sol-gel route to fibre reinforced alumina and mullite composites

Chen, Makan January 1989 (has links)
No description available.
279

Supercritical fluid extraction of organic species through polymeric systems

Ude, Mba January 1999 (has links)
No description available.
280

Microstructural development during heat treatment of PM 2124 Al alloy and 20 vol% SiC composite

Dyos, Kim January 1996 (has links)
No description available.

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