Disorders of cholesterol metabolism were studied in 88 patients with essential or renovascular hypertension, among whom the individual stages of the disease, classified by WHO criteria, were evenly represented. The results were compared with the findings in a group of 87 healthy controls. The following were determined in the plasma: ...

The effect of 5-day sleep deprivation (SD) on cholesterol metabolism, together with triglyceridaemia, was studied in seven healthy male volunteers. A 3-day control period was followed by 5 days (120 h) complete SD and 4 days recovery. Blood was collected at 9 a.m. and at 9 p.m. Vastus lateralis muscle ...

This study was carried out primarily to determine whether the feeding of lecithin (polyenylphosphatidylcholine) has systemic effects on metabolism of cholesterol and triglycerides in patients with endogenous hypertriglyceridemia (type 4 hyperlipoproteinemia). Ten patients were studied during control periods and lecithin feeding. In the former period, 7 g of safflower oil ...

A simple and reproducible radioassay of lecithin cholesterol acyltransferase (LCAT E.C. 2.3.1.43) activity is described. The method is based on cold labelling of the serum, plasma or other LCAT and lipoproteins containing fluids with a trace of 14C-cholesterol spread in ready made sorbent discs. Since the procedure minimizes the chemical, ...

A high cholesterol diet induced a fatty liver and an increase in cholesterol oleate in spontaneously hypertensive rats. The activity of microsomal glycerophosphate acyltransferase in liver increased 2-3-fold to meet the increased supply of oleate, the synthesis of which was stimulated by a 10-fold increase in microsomal delta 9-desaturase activity. ...

Modulation of acyl-CoA: cholesterol acyltransferase (ACAT; EC 2.3.1.26) activity by different diets or coincubation with serum lipoproteins was studied in rabbit liver and intestinal mucosa microsomal preparations. The total amount of cholesterol in the serum lipoproteins, hepatic cells and small intestine mucosa changes in response to changes in cholesterol dietary ...

A case of Tangier disease with results of histological and ultrastructural studies is reported. The clinical, biological and histological picture was typical, with enlarged liver and spleen, voluminous tonsils, low blood levels of alpha-lipoproteins and cholesterol and high blood levels of triglycerides. The histological study revealed widespread tissue storage of ...

The regulation of human plasma lecithin:cholesterol acyltransferase (LCAT) by changes in bilayer fluidity of substrate egg phosphatidylcholine (egg PC) unilamellar vesicles was investigated using pyrene excimer fluorescence to measure fluidity. Fluidity was decreased by adding up to 20% cholesterol or increased by adding up to 10% egg 2-lysophosphatidylcholine (lysoPC). The ...

A baseline model for consideration of the theoretical effects of amniotic fluid volume changes on surfactant concentration measurements has been constructed. The baseline data include: a polynomial equation that best fits experimental data comparing amniotic fluid lecithin concentration measurements to gestational age, inflow of 0.450 L of surfactant-poor fluid into ...

The regulation of lecithin:cholesterol acyltransferase by changes in phospholipid bilayer fluidity was investigated using pyrene excimer fluorescence to measure fluidity. Fluidity of dimyristoylphosphatidylcholine (DMPC) unilamellar vesicles was decreased by the addition of up to 20% (mol/mol) cholesterol and increased by the addition of up to 10% (mol/mol) lysoDMPC. When both ...

The conversion of pig high-density lipoproteins (HDL) (mainly HDL3) to fractions of lower densities was studied by incubating pig plasma for 24 h at 37 degrees C in the presence and absence of lipoprotein lipase from bovine milk, lecithin:cholesterol acyltransferase, cholesteryl ester transfer protein and triacylglycerol-rich particles (very-low-density lipoproteins (VLDL) ...

Studies have been performed to determine the proportion of the esterified cholesterol in high-density lipoproteins (HDL), low-density lipoproteins (LDL) and very-low-density lipoproteins (VLDL) that is attributable to a direct action of lecithin: cholesterol acyltransferase on each lipoprotein fraction. Esterification of [3H]cholesterol was examined in 37 degrees C incubations of either: ...

Incubation (24 h, 37 degrees C) of discoidal complexes of phosphatidylcholine and apolipoprotein A-I (molar ratio 95 +/- 10 egg yolk phosphatidylcholine-apolipoprotein A-I; 10.5 X 4.0 nm, long X short dimension; designated, class 3 complexes) with the ultracentrifugal d greater than 1.21 g/ml fraction transformed the discoidal complexes to a ...

The cholesteryl ester content of plasma low density lipoproteins (LDL) in monkeys has previously been shown to be related to the rate of hepatic cholesterol secretion and cholesteryl ester content of newly secreted lipoproteins in the isolated perfused liver. In the present studies, African green monkeys were fed diets containing ...

The effect of lipid transfer proteins on the exchange and transfer of cholesteryl esters from rat plasma HDL2 to human very low (VLDL) and low density (LDL) lipoprotein populations was studied. The use of a combination of radiochemical and chemical methods allowed separate assessment of [3H]cholesteryl ester exchange and of ...

Macrophages provide an important way for cholesteryl esters to accumulate in tissues in pathologic amounts. We studied cholesteryl ester metabolism in thioglycollate-induced peritoneal macrophages obtained from normocholesterolemic and hypercholesterolemic rabbits. The macrophage preparations from normocholesterolemic rabbit (MN cells) had 26 nmol esterified cholesterol/mg cellular protein, incorporated 1 nmol of labeled ...

Cholesterol net transport, esterification, and cholesteryl ester transfer have been determined in plasma during fasting, and postprandially, after a high fat-cholesterol meal. Significant rises in plasma triglyceride, phospholipid, and free cholesterol were associated with increases in cholesterol net transport, esterification, and transfer (all P less than 0.005), which were well ...

The aim of our study was to define the mechanism by which cholesterol uptake is inhibited by lecithin but not by lysolecithin. The work compared the cholesterol uptake by everted rat jejunal sacs from bile salt-lecithin-cholesterol or bile salt-lysolecithin-cholesterol micelles. The micellar size and the cholesterol saturation were measured. The ...

Opacification of the cornea from lipid accumulation is an early and characteristic feature of familial lecithin:cholesterol acyltransferase (LCAT) deficiency. Visual impairment in a female age 48 years led to keratoplasty and the first detailed analysis of cornea in this disorder. Multilaminar figures were present, and total lipid extracts were enriched ...

To determine how substrate fluidity and molecular structure independently regulate cholesteryl ester formation, the substrate specificity of lecithin:cholesterol acyltransferase with respect to a number of model reassembled high density lipoproteins (R-HDLs) is reported. The R-HDLs are composed of 1 mol % apolipoprotein A-I, 89 mol % of sphingomyelin or a ...

A simple method has been developed for labelling human plasma lipoproteins to high specific radioactivity with radioactive cholesteryl esters in vitro. After isolation by preparative ultracentrifugation, the selected lipoprotein was incubated for 30 min at 4 degrees C in human serum (d greater than 1.215) that had been prelabelled with ...

In non fatal and synchronous P. chabaudi rodent malaria, we observed at the stage of parasitaemia peak, an alteration (50 % decrease) in LCAT activity. This decrease could be related partly to hepatic dysfunction, and mainly to circulating inhibitors released into blood from parasitized red blood cells at each end ...

A simple sensitive method for the determination of the initial rate of the reaction of lecithin-cholesterol acyltransferase by equilibrating [3H]cholesterol with unesterified cholesterol of human serum is described. The resulting serum is incubated for various time periods at 37 degrees C and the increase of the label in the cholesterol ...

The ability of high-density lipoprotein (HDL) to reduce the cholesterol content was studied in cultured fibroblasts enriched with cholesterol esters. Incubation of cholesterol-enriched cells with HDL in a final concentration of 1 g protein/l for 24 h reduced the total and esterified cholesterol content by 23% as compared with control ...

The changes in some parameters of plasma lipoprotein metabolism in 25 hypertensive men, caused by a two months lasting oral treatment with 120 mg propranolol/day, were compared to the changes that occur during the same time in the subjects (n = 9) of an untreated control group. Propranolol led to ...

The effect of total parenteral nutrition (TPN) containing approximately 800 ml Nutralipid daily on plasma cholesterol and lecithin:cholesterol acyl transferase (LCAT) activity was studied in 11 adult hospital patients. LCAT was assayed using an endogenous (S/N) and an artificial (ASA) substrate to differentiate between altered plasma substrate composition (which would ...

The lipid composition of washed erythrocytes from Molossus molossus and Molossus ater were studied. In comparison with other mammalian species, bat erythrocytes were characterized by very high cholesterol/phospholipid molar ratios, as well as by low sphingomyelin content. The lipid composition of bat erythrocytes was similar to that of patients suffering ...

In various organs of the guinea pig, the total cholesterol content of an organ was significantly correlated with the percentage of esterified cholesterol present in this organ. Cholesterol esterifying capacity was shown in most organs, with highest activities in the adrenals, the spleen and the liver. The significant correlation found ...

Microsomal acyl coenzyme A:cholesterol acyltransferase activity of rat intestinal mucosa was measured as the incorporation of [1-14C]oleic acid into cholesterol esters. Exogenous cholesterol and sterol carrier protein singly and together extended the time over which the reaction rate was linear. Cholesterol esterification was suppressed by 2-monooleoyl glyceryl ether a 2-monoglyceride ...

The effects of the anabolic steroid stanozolol (17-methyl-2H-5 alpha-androst-2-eno-(3,2-c)pyrazol-17 beta-ol) on lecithin-cholesterol acyltransferase, apolipoproteins B and D and the Lp(a) lipoprotein were determined in a prospective study of ten normolipidemic women with postmenopausal osteoporosis. Lecithin-cholesterol acyltransferase was reduced approx. 30% by 6 weeks of treatment with stanozolol (off treatment 5.1 ...

The coordinated control of cholesterol biosynthesis and esterification by 25-hydroxycholesterol was studied in the macrophage-like cell line P388D1. Since 25-hydroxycholesterol rapidly stimulated incorporation of [3H]oleate into the cholesteryl ester fraction of these cells, we have tested the possibility that the well-known inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) by ...

These studies were undertaken to examine the effects of lipoprotein lipase (LPL) and cholesteryl ester transfer protein (CETP) on the transfer of cholesteryl esters from high density lipoproteins (HDL) to very low density lipoproteins (VLDL). Human or rat VLDL was incubated with human HDL in the presence of either partially ...

Weanling Wistar rats were pair-fed for 8 days control and magnesium-deficient diets. Acute magnesium deficiency increased plasma triglycerides and free cholesterol levels and decreased esterified cholesterol levels. The plasma activity of lecithin--cholesterol acyltransferase was markedly diminished in fasting magnesium-deficient rats (54% reduction) and plasma high density lipoprotein (HDL) free cholesterol ...

There was a 6-46-fold increase in intracellular cholesterol esterification in response to 25-hydroxycholesterol and low-density lipoproteins in normal and lecithin:cholesterol acyltransferase-deficient fibroblasts. Uptake and degradation of 125I-labelled low-density lipoproteins were similar in the two cell lines. Low-density lipoproteins caused a doubling of the mass of cholesteryl ester in the mutant ...

Previous studies have shown that high concentrations of very low density lipoproteins (VLDL) stimulate the formation of cholesteryl esters in human plasma, possibly by acting as recipients of cholesteryl esters transferred from high density lipoproteins (HDL). To gain further insight into this phenomenon, experiments were performed to determine whether the ...

To identify the temporal changes occurring during progression and regression of atherosclerosis in nonhuman primates, we have studied the physicochemical and histological characteristics of arterial wall lesions during a 30-mo progression period of diet-induced hypercholesterolemia and during a 12-mo period of regression. Three groups of cynomolgous monkeys (Macaca fascicularis) were ...

Cholesterol esterase of pancreatic juice origin and acyl coenzyme A:cholesterol acyltransferase, both associated with the intestinal mucosa, are implicated in the extensive esterification of exogenous cholesterol during absorption. To assess the role of each enzyme, [4-14C]cholesterol absorption into mesenteric lymph of rats with normal mucosal levels of both esterification enzymes ...

Isolated hepatocytes from rats that had been kept in a steady state of [3H]cholesterol were incubated in a salt medium with or without serum. The cells released esterified cholesterol into the incubation medium as lipoproteins. This secretion, 18.1 +/- 0.5 nmol/h per g of cells, was increased when the cells ...

Cholesterol metabolism has been investigated in a strain of BALB/C mice that carry an autosomal recessive mutation associated with decreased sphingomyelinase and glucocerebrosidase activity and storage of sphingomyelin and glucocerebroside as well as cholesterol in lysosomes (Pentchev, P. G., Gal, A. E., Boothe, A. D., Omodeo-Sale, F., Fouks, J., Neumeyer, ...

A lipoprotein fraction possessing many of the characteristics of plasma low density lipoproteins (P-LDL) was isolated from homogenates of lesioned human aortas by affinity chromatography. In contrast to P-LDL, this fraction, termed A-LP, was found to be more electronegative than P-LDL and to stimulate cholesterol esterification in mouse peritoneal macrophages ...

We studied the effect on the serum LCAT activity and apolipoproteins in ten subjects with primary hypercholesterolemia after treatment with beta-sitosterol. The 2-month administration of beta-sitosterol resulted in an increase of the fractional as well as of the molar esterification rate of the LCAT. These alterations were associated with a ...

Little or no information is available on biologically valid labeling of hypercholesterolemic plasma lipoproteins with cholesteryl ester. The esterification of labeled unesterified cholesterol in hypercholesterolemic rabbit plasma by the lecithin: cholesterol acyltransferase reaction is inefficient. The use of the d greater than 1.063 plasma fraction for this reaction greatly improves ...

We studied the effects of the lecithin:cholesterol acyltransferase reaction on the size and composition of the small spherical high density lipoproteins of patients afflicted with familial lecithin:cholesterol acyltransferase deficiency. We isolated these lipoproteins by preparative ultracentrifugation and rate zonal ultracentrifugation, determined their diameter by gradient gel electrophoresis, and then calculated ...

Absorption of cholesterol during inhibition of mucosal acyl CoA:cholesterol acyltransferase was studied in mesenteric lymph fistula rats with normal pancreatic function. The specific inhibitor used (Sandoz Compound 58-035; 3-(decyldimethylsilyl)-N-[2-(4-methylphenyl)-1-phenylethyl]prop anamide) greatly reduced cholesterol esterification in vitro and decreased lymphatic secretion of esterified cholesterol in vivo, but did not affect triglyceride ...

Cholesterol feeding induced a marked hypercholesterolemia with a significant change in the chemical composition of different lipid and lipoprotein fractions. The change of lipoprotein composition in the prairie dog resembles that of human hyper-beta-lipoproteinemia. It is assumed that the mechanism of gallstone formation in humans is not identical to that ...

Compound 58-035 (3-[decyldimethylsilyl]-N-[2-(4-methylphenyl)-1-phenylethyl]pro panamide) has been found to inhibit the accumulation of cholesteryl esters in both rat hepatoma (Fu5AH) cells and arterial smooth muscle cells in culture. To explore the specificity of 58-035, we have studied the esterification of cholesterol, retinol, and glycerides by the Fu5AH cell and by isolated ...

Twenty women, oophorectomized as part of treatment for cervical carcinoma of the cervix participated in the study. Ten of them were given desogestrel (DG) 150 micrograms/day for 3 weeks followed by DG + 30 micrograms ethinyl estradiol (EE) for 6 weeks, and finally EE alone for 3 weeks. The other ...

Intravenous injection of 100 IU heparin per kg body weight caused elevation of the lecithin:cholesterol acyl transfer rate in each one of 11 men, in whom before as well as 5 min and 30 min after heparin application the concentration of unesterified fatty acids in plasma did not reach 0.8 ...

The effects of starvation and of plasma exchange with a cholesterol-free substitute on efflux of tissue cholesterol and on lecithin: cholesterol acyltransferase (LCAT) activity in plasma and peripheral lymph were investigated in two pigs fed a cholesterol diet for 3-4 months. The pigs were labelled with i.v. [14C]cholesterol before plasma ...

Dietary manipulation produces marked alterations in desaturase activities of rat liver microsomes with no concomitant changes in acyltransferase activities. Desaturation of stearoyl-CoA (delta 9-desaturase), linoleoyl-CoA (delta 6-desaturase), eicosatrienoyl-CoA (delta 5-desaturase) and eicosatrienoyl-phosphatidylcholine (delta 5-desaturase) was elevated in animals fed a corn oil diet and lowered in those fed a coconut ...