INTERACTION OF QUARTZ WITH BIOLOGICAL MEMBRANES (SILICOSIS, FIBROSIS, SILICA, PNEUMOCONIOSIS).
Item
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Title
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INTERACTION OF QUARTZ WITH BIOLOGICAL MEMBRANES (SILICOSIS, FIBROSIS, SILICA, PNEUMOCONIOSIS).
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Identifier
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AAI8629719
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identifier
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8629719
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Creator
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NOLAN, ROBERT PATRICK.
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Contributor
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Gerald Oster
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Date
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1986
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Physical
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Abstract
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The interaction of quartz with the macrophage membrane plays a central role in the pathogenesis of silicosis. The erythrocyte has been used as a model to study mineral/membrane interaction. Many pathogenic minerals, including quartz, have the ability to alter the permeability of the erythrocyte membrane. The hemoglobin released by this membranolytic action can be easily quantitated by optical spectroscopy. The variation in membranolytic activity of quartz was studied with respect to surface structure, particle size, and quartz variety. Quartz membranolytic activity can, depending on its surface structure, vary from a level indistinguishable from background lysis to one of potent hemolytic effect. The ratio of the change in hemolytic index closely follows the ratio of the change in surface area. The quartz variety was the least important of the three variables. For a quartz specimen which was shown to be membranolytically active, the contribution of the chemical functionalities on the surface were determined. The two major functional groups on the quartz surface are the silanol group which can undergo hydrogen bonding and the ionized silanol group which impart negative surface charge. The membranolytic activity of quartz has long been attributed to the surface silanol groups. The experimental evidence which supports this hypothesis is the inhibition of membranolytic activity by hydrogen bonding polymers. Blocking the quartz surface charge with metal cations also inhibits the membranolytic effects. To further understand the role of quartz surface charge, experiments were done to identify a receptor on the erythrocyte membrane. When the anion transport receptor, which binds the negative quartz surface charge, was blocked by inhibitors known to complex with it, hemolysis is antagonized. The principles which control quartz membranolytic activity were also found to be applicable to the titanium dioxide polymorphs, rutile and anatase.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Chemistry
