Agents affecting lipid metabolism. XXXVII. Separation of rat serum lipoproteins with dextran sulfate

1969 ◽  
Vol 47 (11) ◽  
pp. 1043-1047 ◽  
Author(s):  
P. Hill ◽  
D. Dvornik
Keyword(s):  
Lipid Metabolism ◽  
Lipid Composition ◽  
Dextran Sulfate ◽  
Fundamental Difference ◽  
High Density ◽  
Low Density ◽  
Serum Lipoproteins ◽  
Rat Serum ◽  
Density Fractions ◽  
Estradiol 17Β

Dextran sulfate was used to separate rat serum lipoproteins into insoluble low-density and soluble high-density fractions. Lipid composition of the separated fractions was compared to that of lipoprotein fractions prepared by ultracentrifugation; data indicate that dextran sulfate precipitates lipoproteins with a density lower than 1.063.In rats treated with ethyl p-chlorophenoxyisobutyrate and estradiol-17β comparable, though not identical, changes in the composition of serum lipoproteins were observed with both methods of separation. The observed differences may reflect the fundamental difference in the basis of separation used by the methods. Data obtained with dextran sulfate may indicate changes in the protein moieties of lipoproteins.

scholarly journals The sites of degradation of rat high-density-lipoprotein apolipoprotein E specifically labelled with O-(4-diazo-3-[125I]iodobenzoyl)sucrose

1985 ◽  
Vol 226 (3) ◽  
pp. 715-721 ◽  
Author(s):  
F M Van't Hooft ◽  
A Van Tol
Keyword(s):  
Serum Proteins ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
High Density ◽  
High Density Lipoproteins ◽  
Low Density ◽  
Serum Lipoproteins ◽  
Rat Serum ◽  
Apo E ◽  
Fasted Rats

O-(4-Diazo-3-[125I]iodobenzoyl)sucrose ([125I]DIBS), a novel labelling compound specifically designed to study the catabolic sites of serum proteins [De Jong, Bouma, & Gruber (1981) Biochem. J. 198, 45-51], was applied to study the tissue sites of degradation of serum lipoproteins. [125I]DIBS-labelled apolipoproteins (apo) E and A-I, added in tracer amounts to rat serum, associate with high-density lipoproteins (HDL) just like conventionally iodinated apo E and A-I. No difference is observed between the serum decays of chromatographically isolated [125I]DIBS-labelled and conventionally iodinated HDL labelled specifically in either apo E or apo A-I. When these specifically labelled HDLs are injected into fasted rats, a substantial [125I]DIBS-dependent 125I accumulation occurs in the kidneys and in the liver. No [125I]DIBS-dependent accumulation is observed in the kidneys after injection of labelled asialofetuin or human low-density lipoprotein. It is concluded that the kidneys and the liver are important sites of catabolism of rat HDL apo E and A-I.

Effect of Estrogens on Rat Serum Lipoproteins

1972 ◽  
Vol 50 (5) ◽  
pp. 474-483 ◽  
Author(s):  
P. Hill ◽  
W. G. Martin
Keyword(s):  
High Density Lipoprotein ◽  
Analytical Ultracentrifugation ◽  
Low Density Lipoprotein ◽  
Subcutaneous Administration ◽  
Density Lipoprotein ◽  
High Density ◽  
Phospholipid Content ◽  
Low Density ◽  
Rat Serum ◽  
Estradiol 17Β

Estrogens, ingredients of contraceptive drugs, were found to affect serum lipids, lipoproteins, and liver lipids of rats selectively. Subcutaneous administration of ethynylestradiol reduced the phospholipid content of the dextran sulfate soluble fraction (HDS) of the serum and decreased the rate of disappearance of the phospholipid moiety, labelled with choline-Me3H in this fraction. Estradiol-17β increased the HDS phospholipid but not its rate of turnover. On analytical ultracentrifugation of the whole serum, no low density lipoprotein was detected and the high density lipoprotein was reduced in ethynylestradiol-treated rats. Ethynylestradiol decreased the phospholipid content and turnover of lecithin in the liver. Both ethynylestradiol and estradiol-17β quantitatively increased the very low density lipoprotein, increasing the phospholipid and triglyceride contents. Data suggested that ethynylestradiol and estradiol-17β affected phospholipid synthesis in the liver to different degrees and one result of this was a change in the proportion of phospholipid in the high density lipoprotein in the rat.

scholarly journals RhoA localization with caveolin-1 regulates vascular contractions to serotonin

2012 ◽  
Vol 303 (9) ◽  
pp. R959-R967 ◽  
Author(s):  
Daniel W. Nuno ◽  
Sarah K. England ◽  
Kathryn G. Lamping
Keyword(s):  
Lipid Rafts ◽  
Rho Kinase ◽  
Initial Response ◽  
Cell Types ◽  
Smooth Muscle Contraction ◽  
High Density ◽  
Low Density ◽  
Density Fractions ◽  
Caveolin 1 ◽  
Multiple Cell

Vascular smooth muscle contraction occurs following an initial response to an increase in intracellular calcium concentration and a sustained response following increases in the sensitivity of contractile proteins to calcium (calcium sensitization). This latter process is regulated by the rhoA/rho kinase pathway and activated by serotonin. In multiple cell types, signaling molecules compartmentalize within caveolae to regulate their activation. We hypothesized that serotonin differentially compartmentalizes rhoA within caveolar versus noncaveolar lipid rafts to regulate sustained vascular contractions. To test this hypothesis, we measured aortic contractions in response to serotonin in wild-type (WT) and cav-1-deficient mice (cav-1 KO). RhoA-dependent contractions in response to serotonin were markedly augmented in arteries from cav-1 KO mice despite a modest reduction in rhoA expression compared with WT. We found that under basal conditions, rhoA in WT arteries was primarily localized within high-density sucrose gradient fractions but temporally shifted to low-density fractions in response to serotonin. In contrast, rhoA in cav-1 KO arteries was primarily in low-density fractions and shifted to high-density fractions in a similar timeframe as that seen in WT mice. We conclude that localization of rhoA to caveolar versus noncaveolar lipid rafts differentially regulates its activation and contractions to rhoA-dependent agonists with greater activation associated with its localization to noncaveolar rafts. Disruption of rhoA localization within caveolae may contribute to increased activation and enhanced vascular contractions in cardiovascular disease.

Speciation in Size and Density Fractionated Fly Ash

1985 ◽  
Vol 65 ◽  
Author(s):  
Raymond T. Hemmings ◽  
Edwin E. Berry
Keyword(s):  
Fly Ash ◽  
Power Plant ◽  
Silicate Glass ◽  
Bituminous Coal ◽  
Particle Density ◽  
High Density ◽  
Low Density ◽  
Density Fractions ◽  
Alumino Silicate ◽  
Low Degrees

ABSTRACTMorphological, chemical and mineralogical speciation of fly ash from a power plant burning sub-bituminous coal has been investigated by examination of size and density fractions. It was found that whereas, fractionation by size revealed little information as to speciation among particle types, separation of the ash into six density fractions showed major differences in properties associated with true particle density. In particular it was found that at least two types of glass co-exist in the ash: “Glass I” – a predominantly silico-aluminous glass associated with particles of low density (cenospheres); “Glass II” – a calcium alumino-silicate glass associated with high-density particles. These glasses were found to differ greatly in composition and to be characterized by shifts in the position of the 2-theta of the XRD-halo. In addition, it was shown that cryptocrystalline mullite is associated only with the low-density particles. It is proposed that particles comprising low-density fractions can be considered as glassceramics with low degrees of crystallization. Particles of high-density are better described as the products of internal lime-sinter reactions.

Improved estimation of cholesteryl ester transfer/exchange activity in serum or plasma.

1986 ◽  
Vol 32 (2) ◽  
pp. 283-286 ◽  
Author(s):  
J E Groener ◽  
R W Pelton ◽  
G M Kostner
Keyword(s):  
Polyethylene Glycol ◽  
Cholesteryl Ester ◽  
Human Plasma ◽  
Dextran Sulfate ◽  
Low Density Lipoproteins ◽  
High Density ◽  
High Density Lipoproteins ◽  
Low Density ◽  
Routine Assay ◽  
Exchange Activity

Abstract This simple, routine assay for measuring cholesteryl ester transfer/exchange activity in human plasma is based on the removal of interfering lipoproteins--very-low-density (VLDL) and low-density lipoproteins (LDL)--by precipitation with polyethylene glycol. High-density lipoproteins (HDL) in the samples do not affect the results. The supernate after precipitation is mixed with [14C]cholesteryl ester-labeled LDL as donor and with HDL as the acceptor for the cholesteryl ester. After incubation for 16 h at 37 degrees C, LDL is separated from HDL by precipitation with dextran sulfate and the radioactivity measured in the supernate, which contains the HDL. The assay is applicable to samples containing as much as 10 mmol of triglycerides per liter. The within-assay CV was 2.7%, the day-to-day CV 6.8%. Results compared well with those by conventional procedures.

Use of Sodium Polyanetholesulfonate-CaCl 2 for Removal of Serum Nonspecific Inhibitors of Rubella Hemagglutination: Comparison with Other Polyanion-Divalent Cation Combinations

1977 ◽  
Vol 6 (4) ◽  
pp. 348-358
Author(s):  
Mary L. Ellins ◽  
James B. Campbell
Keyword(s):  
Molecular Weight ◽  
Divalent Cation ◽  
Dextran Sulfate ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Molecular Weight ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Serum Lipoproteins ◽  
Antibody Testing

By using trypsin-treated human type O cells as indicators, we compared the abilities of four polyanion-divalent cation combinations (heparin-MnCl 2 ; high-and low-molecular-weight dextran sulfate-CaCl 2 ; and sodium polyanetholesulfonate [SPS]-CaCl 2 ) for removal of serum non-immunoglobulin (lipoprotein) inhibitors of rubella hemagglutination. The combination of SPS-CaCl 2 was found to be the most effective, precipitating completely the pre-β and β-lipoproteins and reducing the α-lipoprotein levels by more than 50%. Hemagglutination patterns after this treatment were clear and stable, and, when normal sera were tested, hemagglutination-inhibition (HI) titers were comparable to those obtained after standard heparin-MnCl 2 treatment. High-molecular-weight dextran sulfate-CaCl 2 removed serum lipoproteins almost as effectively as SPS-CaCl 2 . However, problems of nonspecific agglutination and the heavy hemagglutination patterns resulting made this combination unacceptable for routine purposes. Neither low-molecular-weight dextran sulfate-CaCl 2 nor heparin-MnCl 2 removed the pre-β lipoproteins completely, and occasionally traces of β-lipoprotein also remained after treatment. The presence of pre-β lipoproteins in normal sera after treatment may be of no consequence in the HI test since we have found that the very-low-density lipoprotein fractions obtained by ultracentrifugal methods from normal sera (those corresponding to the pre-β fractions obtained by electrophoresis) had no HI activity. However, very-low-density lipoprotein fractions from all hyperlipemic sera tested had HI activity (titers ranging from 1:16 to 1:1,024) which, in the majority of cases, was not eliminated after heparin-MnCl 2 treatment. In every case, treatment with SPS-CaCl 2 removed this nonspecific activity completely. Since hyperlipemic sera may occasionally be encountered in routine rubella HI antibody testing, we recommend the use of SPS-CaCl 2 rather than heparin-MnCl 2 for pretreatment of sera.

Determination of high-density lipoproteins: screening methods compared.

1979 ◽  
Vol 25 (6) ◽  
pp. 939-942 ◽  
Author(s):  
G M Kostner ◽  
P Avogaro ◽  
G B Bon ◽  
G Cazzolato ◽  
G B Quinci
Keyword(s):  
Dextran Sulfate ◽  
Screening Program ◽  
Low Density Lipoproteins ◽  
High Density ◽  
High Density Lipoproteins ◽  
Total Serum ◽  
Screening Methods ◽  
Low Density ◽  
Apolipoprotein A ◽  
Immunochemical Quantitation

Abstract Factors reflecting the concentration of high-density lipoproteins in serum were assessed for 108 men and 106 women participating in a Venetian screening program for hyperlipoproteinemia. The methods applied, optimized in our laboratory, were: (a) cholesterol in high-density lipoproteins, determined in the supernate after sedimentation of the very-low-density lipoproteins + low-density lipoproteins with dextran sulfate or sodium phosphotungstate; and (b) immunochemical quantitation of apolipoprotein A-I and apolipoprotein A-II by Laurell's "rocket" technique. The latter determinations were performed with total serum before and after delipidation with diispropyl ether/n-butanol (6/4 by vol). The dextran sulfate method gave about 5% higher values than did the phosphotungstate method, but the correlation between the two was excellent (r = 0.95). Results of the immunochemical quantitation indicate that delipidation of lipoproteins before Laurell electrophoresis may not be necessary if only freshly drawn sera are used.

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