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1992

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Full-Text Articles in Laboratory and Basic Science Research

Evidence For The Alternative Pathway Of Complement Activation In The Nurse Shark, Lieneke Cecile Culbreath Nov 1992

Evidence For The Alternative Pathway Of Complement Activation In The Nurse Shark, Lieneke Cecile Culbreath

FIU Electronic Theses and Dissertations

Complement is activated via two pathways: classical (CCP) and alternative (ACP). The CCP has been demonstrated in the nurse shark. The ACP has not been demonstrated in any cartilagenous fish. Nurse shark serum was evaluated for complement activity by its ability to lyse heterologous erythrocytes. As CCP activity requires calcium and magnesium, activity of shark serum chelated with EGTA (a selective calcium chelator) or EDTA (a chelator of calcium and magnesium) was assessed. Activity remained in serum chelated with EGTA but not EDTA. Furthermore, activity of chelated serum was enhanced by added magnesium. Activation of shark complement by activators of …

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Development Of Periapical Lesions In Immunosuppressed Rats, Phillip A. Waterman Jr. Aug 1992

Development Of Periapical Lesions In Immunosuppressed Rats, Phillip A. Waterman Jr.

Loma Linda University Electronic Theses, Dissertations & Projects

The pathogenesis of periapical lesions is the interaction of the oral flora with the existing host defenses. The role of bacteria has been established in endodontic disease but the contribution of the host defenses in periapical lesion formation is less clear. The purpose of this study was to compare periapical lesion development in immunosuppressed rats with that in normal rats. Thirty-five, eight-week old Sprague-Dawley rats were equally divided into seven groups. Groups 1, 2, and 3 were given weekly injections of Cytoxan, an immunosuppressive agent. Groups 4, 5, and 6 received no immunosuppressive therapy. Group 7 served as a control, …

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An Evaluation Of Surface Enamel Damage Following The Debonding Of Ceramic Brackets : A Follow-Up Study, B. Scott Hood Jun 1992

An Evaluation Of Surface Enamel Damage Following The Debonding Of Ceramic Brackets : A Follow-Up Study, B. Scott Hood

Loma Linda University Electronic Theses, Dissertations & Projects

To evaluate surface enamel damage after debonding ceramic brackets using their manufacturer's recommended methods, sixty four bicuspid teeth were bonded with three different types of ceramic brackets and one type of metal bracket. All the brackets tested utilized mechanical retention only. The brackets were debonded in the mouth seven to ten days after bonding, extracted and evaluated with a scanning electron microscope. The study concluded that: 1) all brackets alter the surface enamel, 2) there is a significant difference in surface enamel damage between the metal bracket and the ceramic brackets utilizing a tensile debonding method, 3) there is no …

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A Comparison Of Benthic Invertebrate Distributions In Four Ohio River Basin Wetlands, Michael D. Hardin Apr 1992

A Comparison Of Benthic Invertebrate Distributions In Four Ohio River Basin Wetlands, Michael D. Hardin

Morehead State Theses and Dissertations

A thesis presented to the faculty of the Department of Biological and Environmental Sciences at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science in Biology by Michael D. Hardin on April 1, 1992.

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Extinction Of Fear-Potentiated Startle: Blockade By Infusion Of An Nmda Antagonist Into The Amygdala, Michael Davis, William A. Falls, Mindy Miserendino Mar 1992

Extinction Of Fear-Potentiated Startle: Blockade By Infusion Of An Nmda Antagonist Into The Amygdala, Michael Davis, William A. Falls, Mindy Miserendino

Psychology Faculty Publications

Data derived from in vitro preparations indicate that NMDA receptors play a critical role in synaptic plasticity in the CNS. More recently, in vivo pharmacological manipulations have suggested that an NMDA-dependent process may be involved in specific forms of behavioral plasticity. All of the work thus far has focused on the possible role of NMDA receptors in the acquisition of responses. However, there are many examples in the behavioral literature of learning-induced changes that involve the reduction or elimination of a previously acquired response. Experimental extinction is a primary example of the elimination of a learned response. Experimental extinction is …

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