Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Life Sciences
Biochemical Characterization Of The Axolemmal Mitogen For Cultured Schwann Cells, Mark A. Decoster
Biochemical Characterization Of The Axolemmal Mitogen For Cultured Schwann Cells, Mark A. Decoster
Theses and Dissertations
The molecule(s) involved at the axon plasma membrane (axolemma) which causes Schwann cells to proliferate has been investigated by three biochemical techniques: 1) Alkaline extraction of axolemma resulted in recovery of 95% of the mitogenic activity and 50% of the protein in the membrane-bound portion of the axolemma. 2) The axonal mitogen for Schwann cells may be associated with heparan sulfate proteoglycans at the axonal surface. Treatment of axolemma with heparitinase, which cleaves the glycosidic bonds of sulfated glycosaminoglycans, allowed mitogenic activity to be solubilized. 3) Treatment of axolemma with heparin, a highly sulfated glycosaminoglycan analogous to heparan sulfate, resulted …
Evaluation Of The Antagonism Of Nicotine By Mecamylamine And Pempidine In The Brain, Thomas Jeffrey Martin
Evaluation Of The Antagonism Of Nicotine By Mecamylamine And Pempidine In The Brain, Thomas Jeffrey Martin
Theses and Dissertations
Antagonists have been crucial in the characterization of nicotine's pharmacology. Initial evidence for the existence of central nicotinic receptors was based on the fact that nicotine produced a number of behavioral effects that were antagonized by ganglionic blockers that crossed the blood-brain barrier, such as mecamylamine and pempidine. Although the mechanism of action of these compounds has been studied extensively in the periphery, little is known about their mechanisms of action in the brain. These compounds are thought to be noncompetitive antagonists due to the fact that they do not compete for agonist binding to brain homogenate in vitro. However, …
Characterization Of Steroid-17,20-Desmolase And 20Α-Hydroxysteroid Dehydrogenase From Clostridium Scindens, Amy Elizabeth Krafft
Characterization Of Steroid-17,20-Desmolase And 20Α-Hydroxysteroid Dehydrogenase From Clostridium Scindens, Amy Elizabeth Krafft
Theses and Dissertations
Clostridium scindens is an obligate anaerobe isolated from the normal intestinal flora of man. It is the only bacterium known at present to synthesize both steroid-17,20-desmolase and 20α-hydroxysteroid dehydrogenase (ZOα-HSDH). This study was undertaken to characterize these neutral steroid transforming reactions in extracts of C. scindens; to purify and characterize the enzymes responsible for side-chain cleavage and 20α- hydroxysteroid oxidoreduction and to clone the genes encoding these enzymes with a view towards studying the mechanism of induction by steroids in a prokaryotic system. Both enzymes were found to be co-inducible in cells cultured in the presence of 17α-hydroxysteroids. In cell …