The Experts below are selected from a list of 48105 Experts worldwide ranked by ideXlab platform
George H Rothblat - One of the best experts on this subject based on the ideXlab platform.
-
use of Cyclodextrins for manipulating cellular cholesterol content
Journal of Lipid Research, 1997Co-Authors: A E Christian, M P Haynes, Michael C Phillips, George H RothblatAbstract:Previous studies from this laboratory have demonstrated that exposure of tissue culture cells to Cyclodextrins results in rapid cholesterol depletion. In the present study, we have developed experimental systems for using solutions of Cyclodextrins, either 2-hydroxypropyl beta-Cyclodextrin or methylated beta-Cyclodextrin, complexed with varying amounts of free cholesterol to manipulate cell cholesterol content. Cholesterol delivered via the Cyclodextrin has been found to be metabolically active, as measured by the acyl-coenzyme A:cholesterol acyltransferase (ACAT)-mediated esterification of [3H]cholesterol in Fu5AH rat hepatoma cells and Chinese hamster ovary cells. The methylated beta-Cyclodextrin was found to be a more efficient donor in all cell types studied, with an average cholesterol uptake of at least 100 microg cholesterol/mg protein within 6 h. By modifying the Cyclodextrin:cholesterol molar ratio, it is possible to manipulate the cellular cholesterol content of cells, producing conditions ranging from net cholesterol enrichment to depletion. The use of Cyclodextrins provides a convenient, precise and reproducible method for modulating the cholesterol content of tissue culture cells.
-
cellular cholesterol efflux mediated by Cyclodextrins
Journal of Biological Chemistry, 1995Co-Authors: E P C Kilsdonk, Michael C Phillips, Patricia G Yancey, Genevieve W Stoudt, Faan Wen Bangerter, William J Johnson, George H RothblatAbstract:In this study, we compared cholesterol efflux mediated by either high density lipoproteins (HDL3) or beta-Cyclodextrins, cyclic oligosaccharides that are able to dissolve lipids in their hydrophobic core. beta-Cyclodextrin, 2-hydroxypropyl-beta-Cyclodextrin, and methyl-beta-Cyclodextrin at 10 mM induced the release of 50-90% of L-cell [3H]cholesterol after 8 h of incubation, with a major portion of this cholesterol being released in the first 1-2 h of incubation. The cholesterol efflux kinetics are different if cells are incubated with HDL3, which induces a relatively constant rate of release of cholesterol throughout an 8-h incubation. Cholesterol efflux to Cyclodextrins was much greater than phospholipid release. To test the hypothesis that maximal efflux rate constants for a particular cell are independent of the type of acceptor, we estimated the maximal rate constants for efflux (Vmax) of cellular cholesterol from L-cells, Fu5AH cells, and GM3468A fibroblasts. The rate constant for HDL3-mediated efflux varied among cell lines in the order Fu5AH > L-cells > fibroblasts. However, these differences were not evident when Cyclodextrins were used as cholesterol acceptors. The estimated Vmax values for Cyclodextrin-mediated efflux were 3.5-70-fold greater than for HDL3 for the three cell lines. The very high efficiency of Cyclodextrins in stimulating cell cholesterol efflux suggests that these compounds can be used in two general ways for studies of atherosclerosis: 1) as research tools to probe mechanisms of cholesterol transport and aspects of membrane structure or 2) as potential pharmacological agents that could modify in vivo cholesterol metabolism and influence the development of the atherosclerotic plaque.
-
cellular cholesterol efflux mediated by Cyclodextrins
Journal of Biological Chemistry, 1995Co-Authors: E P C Kilsdonk, Michael C Phillips, Patricia G Yancey, Genevieve W Stoudt, Faan Wen Bangerter, William J Johnson, George H RothblatAbstract:In this study, we compared cholesterol efflux mediated by either high density lipoproteins (HDL3) or β-Cyclodextrins, cyclic oligosaccharides that are able to dissolve lipids in their hydrophobic core. β-Cyclodextrin, 2-hydroxypropyl-β-Cyclodextrin, and methyl-β-Cyclodextrin at 10 mM induced the release of 50-90% of L-cell [3H]cholesterol after 8 h of incubation, with a major portion of this cholesterol being released in the first 1-2 h of incubation. The cholesterol efflux kinetics are different if cells are incubated with HDL3, which induces a relatively constant rate of release of cholesterol throughout an 8-h incubation. Cholesterol efflux to Cyclodextrins was much greater than phospholipid release. To test the hypothesis that maximal efflux rate constants for a particular cell are independent of the type of acceptor, we estimated the maximal rate constants for efflux (Vmax) of cellular cholesterol from L-cells, Fu5AH cells, and GM3468A fibroblasts. The rate constant for HDL3-mediated efflux varied among cell lines in the order Fu5AH > L-cells > fibroblasts. However, these differences were not evident when Cyclodextrins were used as cholesterol acceptors. The estimated Vmax values for Cyclodextrin-mediated efflux were 3.5-70-fold greater than for HDL3 for the three cell lines. The very high efficiency of Cyclodextrins in stimulating cell cholesterol efflux suggests that these compounds can be used in two general ways for studies of atherosclerosis: 1) as research tools to probe mechanisms of cholesterol transport and aspects of membrane structure or 2) as potential pharmacological agents that could modify in vivo cholesterol metabolism and influence the development of the atherosclerotic plaque.
Matthew E Mccarroll - One of the best experts on this subject based on the ideXlab platform.
-
chiral recognition of 1 1 binaphthyl 2 2 diyl hydrogenphosphate using fluorescence anisotropy
Journal of Photochemistry and Photobiology A-chemistry, 2007Co-Authors: Matthew E MccarrollAbstract:Abstract The photophysical properties of 1,1′-binaphthyl-2,2′-diyl hydrogenphosphate (BNP) have been examined with particular emphasis to the effects of the chiral recognition of BNP by α-, β-, and γ-Cyclodextrins (CDs). Fluorescence spectra and anisotropy values of the BNP enantiomers were measured in the presence and absence of the CDs under various conditions and the chiral recognition behavior are discussed based on the acquired fluorescence data. Small spectral shifts in the fluorescence emission allowed evaluation of the binding constant and enantioselectivity of the binding in β-, and γ-Cyclodextrin, but significant shifts were not observed in the case of α-Cyclodextrin. Fluorescence anisotropy proved to be an effective technique to study the enantioselective interactions, even in the case of α-Cyclodextrin where a smaller binding constant and enantiodiscrimination were confirmed. The differential thermodynamics of binding were examined by fluorescence anisotropy and are discussed with reference to the general structural characteristic of the Cyclodextrins examined. Interestingly, BNP was found to exhibit opposite thermodynamic trends for β-Cyclodextrin at low (1 mM) and high (11 mM) Cyclodextrin concentrations, indicating the possibility of complex of even different modes of enantiodiscrimination in this system.
Danuta Sybilska - One of the best experts on this subject based on the ideXlab platform.
-
comparative study on the enantiomer separation of 1 1 binaphthyl 2 2 diyl hydrogenphosphate and 1 1 bi 2 naphthol by liquid chromatography and capillary electrophoresis using single and combined chiral selector systems
Journal of Chromatography A, 2002Co-Authors: Anna Bielejewska, Kazimiera Duszczyk, Arkadiusz Kwaterczak, Danuta SybilskaAbstract:The chiral recognition ability of single and dual selectors, that were used as additives, have been investigated by HPLC and CE. Native beta- and gamma-Cyclodextrins, permethylated beta-Cyclodextrin, hydroxypropyl-beta-Cyclodextrin, cholic acid and taurodeoxycholic acid sodium salts were applied as chiral selectors, whereas the atropisomers of 1,1'-binaphthyl-2,2'-diyl hydrogenphosphate, and 1,1'-bi-2-naphthol served as model compounds. It was found that all investigated selectors, except for gamma-Cyclodextrin, display the same affinity pattern for binaphthyl enantiomers, i.e., binding the S more strongly than the R enantiomer. However, the differences in the phase distribution of chiral selectors led to the opposit elution order of enantiomers: with Cyclodextrins, the first eluted is S enantiomer, while R is the first eluted for bile salts. Under the conditions studied, Cyclodextrins (except gamma-Cyclodextrin), as well as cholic acid sodium salts acting singly, enable the separation of 1,1'-binaphthyl-2,2'-diyl hydrogenphosphate enantiomers both by HPLC and CE methods, while 1,1'-bi-2-naphthol enantiomers were resolved only under CE conditions with permethylated Cyclodextrin or bile salts. In both techniques the application of dual systems could improve resolution or make it worse (oreven cancel), depending on the sign of enantioselectivity of particular selectors, their concentrations and localization: mobile or stationary phase. It has been found that the mechanism of separation as well as interactions occurring between two selectors may be followed by using combined HPLC and CE methods. The obtained results proved that, as well as beta-CD, TM-beta-D and gamma-CD also form inclusion complexes with cholic acid sodium salts. The reversal of elution order may be realized by two procedures: changing a single selector, i.e., Cyclodextrin on cholic acid sodium salt or vice versa, and by changing the proportion of selectors in the combined bile salt-Cyclodextrin system.
E P C Kilsdonk - One of the best experts on this subject based on the ideXlab platform.
-
cellular cholesterol efflux mediated by Cyclodextrins
Journal of Biological Chemistry, 1995Co-Authors: E P C Kilsdonk, Michael C Phillips, Patricia G Yancey, Genevieve W Stoudt, Faan Wen Bangerter, William J Johnson, George H RothblatAbstract:In this study, we compared cholesterol efflux mediated by either high density lipoproteins (HDL3) or beta-Cyclodextrins, cyclic oligosaccharides that are able to dissolve lipids in their hydrophobic core. beta-Cyclodextrin, 2-hydroxypropyl-beta-Cyclodextrin, and methyl-beta-Cyclodextrin at 10 mM induced the release of 50-90% of L-cell [3H]cholesterol after 8 h of incubation, with a major portion of this cholesterol being released in the first 1-2 h of incubation. The cholesterol efflux kinetics are different if cells are incubated with HDL3, which induces a relatively constant rate of release of cholesterol throughout an 8-h incubation. Cholesterol efflux to Cyclodextrins was much greater than phospholipid release. To test the hypothesis that maximal efflux rate constants for a particular cell are independent of the type of acceptor, we estimated the maximal rate constants for efflux (Vmax) of cellular cholesterol from L-cells, Fu5AH cells, and GM3468A fibroblasts. The rate constant for HDL3-mediated efflux varied among cell lines in the order Fu5AH > L-cells > fibroblasts. However, these differences were not evident when Cyclodextrins were used as cholesterol acceptors. The estimated Vmax values for Cyclodextrin-mediated efflux were 3.5-70-fold greater than for HDL3 for the three cell lines. The very high efficiency of Cyclodextrins in stimulating cell cholesterol efflux suggests that these compounds can be used in two general ways for studies of atherosclerosis: 1) as research tools to probe mechanisms of cholesterol transport and aspects of membrane structure or 2) as potential pharmacological agents that could modify in vivo cholesterol metabolism and influence the development of the atherosclerotic plaque.
-
cellular cholesterol efflux mediated by Cyclodextrins
Journal of Biological Chemistry, 1995Co-Authors: E P C Kilsdonk, Michael C Phillips, Patricia G Yancey, Genevieve W Stoudt, Faan Wen Bangerter, William J Johnson, George H RothblatAbstract:In this study, we compared cholesterol efflux mediated by either high density lipoproteins (HDL3) or β-Cyclodextrins, cyclic oligosaccharides that are able to dissolve lipids in their hydrophobic core. β-Cyclodextrin, 2-hydroxypropyl-β-Cyclodextrin, and methyl-β-Cyclodextrin at 10 mM induced the release of 50-90% of L-cell [3H]cholesterol after 8 h of incubation, with a major portion of this cholesterol being released in the first 1-2 h of incubation. The cholesterol efflux kinetics are different if cells are incubated with HDL3, which induces a relatively constant rate of release of cholesterol throughout an 8-h incubation. Cholesterol efflux to Cyclodextrins was much greater than phospholipid release. To test the hypothesis that maximal efflux rate constants for a particular cell are independent of the type of acceptor, we estimated the maximal rate constants for efflux (Vmax) of cellular cholesterol from L-cells, Fu5AH cells, and GM3468A fibroblasts. The rate constant for HDL3-mediated efflux varied among cell lines in the order Fu5AH > L-cells > fibroblasts. However, these differences were not evident when Cyclodextrins were used as cholesterol acceptors. The estimated Vmax values for Cyclodextrin-mediated efflux were 3.5-70-fold greater than for HDL3 for the three cell lines. The very high efficiency of Cyclodextrins in stimulating cell cholesterol efflux suggests that these compounds can be used in two general ways for studies of atherosclerosis: 1) as research tools to probe mechanisms of cholesterol transport and aspects of membrane structure or 2) as potential pharmacological agents that could modify in vivo cholesterol metabolism and influence the development of the atherosclerotic plaque.
Michael C Phillips - One of the best experts on this subject based on the ideXlab platform.
-
use of Cyclodextrins for manipulating cellular cholesterol content
Journal of Lipid Research, 1997Co-Authors: A E Christian, M P Haynes, Michael C Phillips, George H RothblatAbstract:Previous studies from this laboratory have demonstrated that exposure of tissue culture cells to Cyclodextrins results in rapid cholesterol depletion. In the present study, we have developed experimental systems for using solutions of Cyclodextrins, either 2-hydroxypropyl beta-Cyclodextrin or methylated beta-Cyclodextrin, complexed with varying amounts of free cholesterol to manipulate cell cholesterol content. Cholesterol delivered via the Cyclodextrin has been found to be metabolically active, as measured by the acyl-coenzyme A:cholesterol acyltransferase (ACAT)-mediated esterification of [3H]cholesterol in Fu5AH rat hepatoma cells and Chinese hamster ovary cells. The methylated beta-Cyclodextrin was found to be a more efficient donor in all cell types studied, with an average cholesterol uptake of at least 100 microg cholesterol/mg protein within 6 h. By modifying the Cyclodextrin:cholesterol molar ratio, it is possible to manipulate the cellular cholesterol content of cells, producing conditions ranging from net cholesterol enrichment to depletion. The use of Cyclodextrins provides a convenient, precise and reproducible method for modulating the cholesterol content of tissue culture cells.
-
cellular cholesterol efflux mediated by Cyclodextrins
Journal of Biological Chemistry, 1995Co-Authors: E P C Kilsdonk, Michael C Phillips, Patricia G Yancey, Genevieve W Stoudt, Faan Wen Bangerter, William J Johnson, George H RothblatAbstract:In this study, we compared cholesterol efflux mediated by either high density lipoproteins (HDL3) or beta-Cyclodextrins, cyclic oligosaccharides that are able to dissolve lipids in their hydrophobic core. beta-Cyclodextrin, 2-hydroxypropyl-beta-Cyclodextrin, and methyl-beta-Cyclodextrin at 10 mM induced the release of 50-90% of L-cell [3H]cholesterol after 8 h of incubation, with a major portion of this cholesterol being released in the first 1-2 h of incubation. The cholesterol efflux kinetics are different if cells are incubated with HDL3, which induces a relatively constant rate of release of cholesterol throughout an 8-h incubation. Cholesterol efflux to Cyclodextrins was much greater than phospholipid release. To test the hypothesis that maximal efflux rate constants for a particular cell are independent of the type of acceptor, we estimated the maximal rate constants for efflux (Vmax) of cellular cholesterol from L-cells, Fu5AH cells, and GM3468A fibroblasts. The rate constant for HDL3-mediated efflux varied among cell lines in the order Fu5AH > L-cells > fibroblasts. However, these differences were not evident when Cyclodextrins were used as cholesterol acceptors. The estimated Vmax values for Cyclodextrin-mediated efflux were 3.5-70-fold greater than for HDL3 for the three cell lines. The very high efficiency of Cyclodextrins in stimulating cell cholesterol efflux suggests that these compounds can be used in two general ways for studies of atherosclerosis: 1) as research tools to probe mechanisms of cholesterol transport and aspects of membrane structure or 2) as potential pharmacological agents that could modify in vivo cholesterol metabolism and influence the development of the atherosclerotic plaque.
-
cellular cholesterol efflux mediated by Cyclodextrins
Journal of Biological Chemistry, 1995Co-Authors: E P C Kilsdonk, Michael C Phillips, Patricia G Yancey, Genevieve W Stoudt, Faan Wen Bangerter, William J Johnson, George H RothblatAbstract:In this study, we compared cholesterol efflux mediated by either high density lipoproteins (HDL3) or β-Cyclodextrins, cyclic oligosaccharides that are able to dissolve lipids in their hydrophobic core. β-Cyclodextrin, 2-hydroxypropyl-β-Cyclodextrin, and methyl-β-Cyclodextrin at 10 mM induced the release of 50-90% of L-cell [3H]cholesterol after 8 h of incubation, with a major portion of this cholesterol being released in the first 1-2 h of incubation. The cholesterol efflux kinetics are different if cells are incubated with HDL3, which induces a relatively constant rate of release of cholesterol throughout an 8-h incubation. Cholesterol efflux to Cyclodextrins was much greater than phospholipid release. To test the hypothesis that maximal efflux rate constants for a particular cell are independent of the type of acceptor, we estimated the maximal rate constants for efflux (Vmax) of cellular cholesterol from L-cells, Fu5AH cells, and GM3468A fibroblasts. The rate constant for HDL3-mediated efflux varied among cell lines in the order Fu5AH > L-cells > fibroblasts. However, these differences were not evident when Cyclodextrins were used as cholesterol acceptors. The estimated Vmax values for Cyclodextrin-mediated efflux were 3.5-70-fold greater than for HDL3 for the three cell lines. The very high efficiency of Cyclodextrins in stimulating cell cholesterol efflux suggests that these compounds can be used in two general ways for studies of atherosclerosis: 1) as research tools to probe mechanisms of cholesterol transport and aspects of membrane structure or 2) as potential pharmacological agents that could modify in vivo cholesterol metabolism and influence the development of the atherosclerotic plaque.
