A comparative fluorescence polarization study of cis-parinaroyl-phosphatidylcholine and diphenylhexatriene in membranes containing different amounts of cholesterol

Christiansson, A.; Kuypers, Frans A.; Roelofsen, B.; Wirtz, K.W.A.; Kamp, J.A.F. Op den

doi:10.1016/0009-3084(84)90050-1

Cited by 9 publications

(1 citation statement)

References 40 publications

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“…1 and 4); yet the increase in membrane viscosity due to even higher enrichment of di 16 : 0-PC is small (less than 10%, ref. [3]) compared to the 40% rise in membrane viscosity seen upon increasing membrane C/P ratio from 0.85 to 1.2 [5]. It is thus unlikely, that changes in membrane viscosity can offer an explanation for the effects of both the sterol and the phospholipid on the kinetics of Na-Li exchange.…”

Section: Resultsmentioning

confidence: 77%

Effect of cholesterol and dipalmitoyl phosphatidylcholine enrichment on the kinetics of Na−Li exchange of human erythrocytes

Engelmann

Duhm

1991

J. Membrain Biol.

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The effects of cholesterol loading and depletion and of a 10% replacement of native phosphatidylcholine by dipalmitoyl phosphatidylcholine (di 16:0-PC) on kinetic properties of human red cell Na-Li exchange have been studied. Compared to control erythrocytes (cholesterol/phospholipid ratio (C/P = 0.8-0.9], Vmax of phloretin-sensitive Li uptake and of Li efflux stimulated by extracellular Na (Nao) were reduced by 15-30% in cholesterol-loaded red cells (C/P = 1.05-1.33). The apparent Km values for external Li (Lio) and for internal Li (Lii) were decreased by about one-third in these cells. Cholesterol depletion (C/P = 0.7) exerted opposite effects on the kinetics of Nao-dependent Li efflux. On augmenting C/P from 0.66 to 1.0, Vmax of Nao-dependent Li efflux was reduced by about 30%; increasing C/P above 1.0 caused no further lowering of Vmax.Li leakage rates monotonically decreased over the whole range of C/P ratios examined (0.66-1.3). This indicates that Na-Li exchange and Li leak are differentially affected by cholesterol. Incorporation of di 16:0-PC (replacement of 3% of total red cell phospholipids) caused similar kinetic alterations of Na-Li exchange as a rise in membrane cholesterol by 20-50%. Notably, selective incorporation of di 16:0-PC into the outer monolayer increased both intra- and extracellular Li binding affinities of Na-Li exchange and lowered its maximum velocity. Thus, both di 16:0-PC enrichment and cholesterol loading exerted an uncompetitive type of transport inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Resultsmentioning

confidence: 77%

Effect of cholesterol and dipalmitoyl phosphatidylcholine enrichment on the kinetics of Na−Li exchange of human erythrocytes

Engelmann

Duhm

1991

J. Membrain Biol.

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Flow cytometric detection of micronuclei by combined staining of DNA and membranes

Wessels

Nüsse

1995

Cytometry

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A new staining method is presented for flow cytometric measurement of micronuclei (MN) in cell cultures and human lymphocytes using membranespecific fluorescent dyes in addition to DNA staining. Several Key terms: UV-B-induced micronuclei, automation of micronucleus scoring, flow cytometry, membrane-specific dyesThe measurement of the frequency of micronuclei (MN) induced in cells by ionizing radiation or by treatment with chemicals is widely used for analysis of cytogenetic damage. MN contain genetic material that is lost from the genome of cells during mitosis (10). Because microscopic scoring of MN in some hundreds or thousands of cells is a time-consuming procedure, several attempts have been made to automate MN scoring by image analysis (S,l5,20) or by flow cytometry (4,ll-14,22). Several years ago, we developed a flow cytometric technique using a suspension of nuclei and MN for flow cytometric measurement of DNA content, enabling us to measure frequency and DNA content of MN (12). Light scatter intensities (forward and side scatter) were also used for a better discrimination between debris and MN, because these signals give additional information on size and structure of these particles (4,13,14,22). For the analysis of MN in lymphocytes, a combination of two DNA dyes (HO and EB) was used (lS,19). A remaining problem is that there are regions of low signal intensities, where discrimination of debris and MN is not obvious. Especially in rat hepatocytes used for the testing of cytogenetic damage of chemicals by flow cytometric analysis of MN (4) and in human lymphocytes ( 2 1 ), the overlay of nonspecific debris and MN can still be a major problem for the analysis of MN.We have, therefore, developed a new staining technique for flow cytometric analysis of MN using membrane-specific dyes in addition to the DNA dyes, especially for those cell types where a large amount of nonspecific debris was found after the preparation of a suspension of nuclei and MN. For staining of membranes of nuclei, MN, as well as membrane particles in the nonspecific debris, the lipophilic dyes 2-hydroxyethyl-7,12,17-tris( methoxyethy1)porphycene (HEPn) and 1,6-diphenyl-l,3,5-hexatriene (DPH) were used. It has been shown that these fluorescent dyes are located within the regions of the hydrocarbon bondings of membranes of cells (1,23). Due to their lipophilic character, they have to be dissolved in organic solvents or in the lipid phase of Address reprint requests to J.M. Wessels, GSF-lnst. f i r Biophysikalische Strahlenforschung, Arbeitsgruppe DurcMulLbytometrie, Neuherberg,

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Fluorescence Depolarization Techniques in Materials Science

Birch

Karolin

Standardization and Quality Assurance in Fluorescence Measurements I

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A comparative fluorescence polarization study of cis-parinaroyl-phosphatidylcholine and diphenylhexatriene in membranes containing different amounts of cholesterol

Cited by 9 publications

References 40 publications

Effect of cholesterol and dipalmitoyl phosphatidylcholine enrichment on the kinetics of Na−Li exchange of human erythrocytes

Effect of cholesterol and dipalmitoyl phosphatidylcholine enrichment on the kinetics of Na−Li exchange of human erythrocytes

Flow cytometric detection of micronuclei by combined staining of DNA and membranes

Fluorescence Depolarization Techniques in Materials Science

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