bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of cholesterol synthesis in four colonic adenocarcinoma cell lines
Authors: Cerda Sonia R. , Wilkinson John , Broitman Selwyn A. 
Published: November 2006

AbstractColon tumor cells, unlike normal human fibroblasts, exhibited an uncoupling of low density lipoprotein (LDL)‐derived cholesterol from cellular growth, when endogenous cholesterol synthesis was inhibited by mevinolin, a hydroxymethylglutaryl‐CoA reductase (HMG‐CoAR) competitive inhibitor [Fabricant, M., and Broitman, S.A. (1990)Cancer Res. 50, 632–636]. Further evaluation of cholesterol metabolism was conducted in two undifferentiated (SW480, SW1417) and two differentiated (HT29, CACO2) colonic adenocarcinoma (adeno‐CA) cell lines and an untransformed human fibroblast, AG1519A. Cells grown in monolayer culture to near subconfluency were used to assess endogenous cholesterol synthesis by14C‐acetate incorporation, in response to the following treatments in lipoprotein‐deficient serum (LPDS)‐supplemented minimum essential medium (MEM): LPDS alone, LDL, mevinolin, mevinolin with LDL, and 25‐hydroxy‐cholesterol (25‐OH‐CH). Complete fetal bovine serum (FBS)‐supplemented MEM was used as control. All colon tumor lines exhibited similarly high endogenous cholesterol synthesis in both FBS and LPDS relative to the fibroblasts which demonstrated low basal levels in FBS and maximal synthesis in LPDS. LDL treatment did not inhibit cholesterol synthesis in colon tumor cells, but suppressed that in the fibroblast by 70%. Sterol repression of cholesterol synthesis mediated by 25‐OH‐CH occurred in all cells. Mevinolin caused a reduction in cholesterol synthesis in the colonic cancer cell lines, which was not further decreased by concurrent addition of LDL. In contrast, in mevinolin‐treated fibroblasts, LDL further inhibited cholesterol synthesis. When the effect of cell density on cholesterol synthesis regulation was evaluated under conditions of sparse density in SW480 and SW1417, results indicated that (i) basal rates of cholesterol synthesis were higher, (ii) LDL inhibited cholesterol synthesis more effectively, and (iii) mevinolin or 25‐OH‐CH had a more pronounced effect than in subconfluent cells. Evaluation of LDL receptor activity through125I‐LDL binding and internalization studies demonstrated LDL receptor expression was reduced by 37% in normal density cells relative to the low density cultures. In contrast to cholesterol synthesis, exogenous LDL could inhibit LDL receptor activity at both densities. Thus subconfluent growing colonic adenoCA cell lines retain the capacity for sterol repression, but, in contrast to normal fibroblasts, exhibit a high endogenous cholesterol synthesis which LDL cannot regulate.
Functional and ultrastructural effects of essential fatty acid deficiency in kidney epithelial cells
Authors: Stoll Lynn L. , Spector Arthur A. 
Published: November 2006

AbstractMadin‐Darby canine kidney (MDCK) epithelial cells were grown in culture medium supplemented with 1% fetal bovine serum (FBS) to provide a cell culture model of essential fatty acid deficiency (EFAD). 5,8,11‐Eicosatrienoic acid (20∶3n−9) accumulated in cellular phospholipids, and arachidonic acid (20∶4) decreased. A large increase in cellular cholesterol/phospholipid ratio was observed. Hemicyst formation was greatly reduced from normal levels in the EFAD‐MDCK cells. Scanning and transmission electron microscopy revealed that EFAD‐MDCK were much flatter than their normal counterparts. They had much less dense surface microvilli, mitochondria and other organelles were very sparse, except in the perinuclear area, and much of the peripheral cytoplasm was amorphous. The EFAD was rapidly reversed by the addition of as little as 10 μM linoleic or arachidonic acid to the medium. Cells supplemented with 10% FBS, the usual culture condition, displayed borderline EFAD, with intermediate levels of 20∶3n−9 and 20∶4 and hemicyst formation. These studies suggest that EFAD reduces water and electrolyte transport in renal tubular epithelium.
Effect of marine oils supplementation on coagulation and cellular activation in whole blood
Authors: Østerud Bjarne , Elvevoll Edel , Barstad Harald , Brox Jan , Halvorsen Hanne , Lia Karin , Olsen Jan Ole , Olsen Ragnar L. , Sissener Charlotte , Rekdal Øystein , Vognild Eva 
Published: November 2006

AbstractA study was performed to explore the effects of supplemental intake of various marine oils known to be part of the Eskimo diet. Healthy men and women (134) were randomly selected to consume 15 mL/d of oil from blubber of seal, cod liver, seal/cod liver, blubber of Minke whale, or no oil for ten weeks. Total cholesterol was unchanged in the oil groups, whereas high density lipoprotein cholesterol increased 7% in the seal/cod liver oil (CLO) group (P<0.05) and 11% in the whale oil group (P<0.005). Triacylglycerol was significantly reduced in the CLO group only. The concentration of prothrombin fragment 1+2 was reduced 25% (P<0.05) after whale oil supplementation. No change in fibrinogen or factor VIIc was detected. Tumor necrosis factor generation in lipopolysaccharide (LPS)‐stimulated blood was 30% reduced after whale oil (P<0.05), but was unaffected by intake of seal or CLO. The LPS‐induced tissue factor activity in monocytes was reduced to a significant degree only in the seal/CLO group (34%) and whale oil group (35%) (P<0.05). The most dramatic change in thromboxane B2 in LPS‐stimulated blood was seen after whale oil intake with 44% reduction (P<0.01). Supplementation of a regular diet with a combination of seal oil and CLO and especially with whale oil seems to have beneficial effects on several products thought to be associated with cardiovascular and thrombotic diseases.
Molecular architecture and biophysical properties of phospholipids during thermal adaptation in fish: An experimental and model study
Authors: Fodor Elfrieda , Jones Richard H. , Buda Csaba , Kitajka Klara , Dey Indranil , Farkas Tibor 
Published: November 2006

AbstractPhospholipids from livers of carps (Cyprinus carpio L.) adapted to winter (5°C) and summer (25°C) temperatures were isolated, and the fatty acid composition of total phospholipids, as well as molecular species composition of diacyl phosphatidylcholines and ethanolamines, were determined. Order parameter of 5‐doxyl stearic acid and steady‐state fluorescence anisotropy of different anthroyloxy fatty acids—[2‐, 12(N‐9‐anthroyloxy)stearic acid and 16(N‐9‐anthroyloxy)palmitic acid—embedded in native and synthetic (16∶0/16∶0, 16∶0/22∶6, 18∶0/22∶6, 18∶1/22∶6, 20∶4/20∶4, 22∶6/22∶6 phosphatidylcholines and 16∶0/18∶1, 18∶1/22∶6 phosphatidylethanolamines) phospholipid vesicles was also determined between −30 and 30°C and 5 and 30°C, respectively. There is an accumulation of 1‐monoenoic, 2‐polyenoic diacyl phosphatidylcholine and ethanolamine with a concomitant reduction of 1‐stearoyl,2‐docosahexaenoyl species in the cold‐adapted state. Despite a 30% accumulation of long‐chain polyunsaturated fatty acids in phospholipids in cold, there is only a 5°C downshift in the solid‐gel to liquid‐crystalline phase transition temperature (−8 vs. −13°C). Vesicles from total phospholipids of cold‐adapted fish proved to be more disordered in all segments than from the warmadapted ones when assayed using 2,12‐(N‐9‐anthroyloxy)stearic and 16‐(N‐9‐anthroyloxy)palmitic acid. Vesicles made from purified phosphatidylcholines showed the same pattern, but they were more disordered than the corresponding total phospholipids. This could be modelled using mixed phospholipid vesicles made of synthetic 16∶0/22∶6 phosphatidylcholine (75%) and either 18∶1/22∶6 phosphatidylethanolamine (25%) vs. 16∶0/18∶1 phosphatidylethanolamine (25%) and comparison of the anisotropy parameters of 100% 16∶0/22∶6 and 100% 18∶1/22∶6 phosphatidylcholine vesicles. Mixing either 16∶0/18∶1 (25%) or 18∶1/22∶6 (25%) phosphatidylethanolamines to 18∶0/22∶6 (75%) phosphatidylcholine shifted down or up, respectively, the transition temperature of vesicles compared to 100% 18∶0/22∶6 vesicles assayed by electron spin resonance spectroscopy using 5‐doxylstearic acid. It is concluded that it is not the gross amount of long‐chain polyunsaturated fatty acids in phospholipids, but rather their specific combination withcis Δ9 monounsaturated fatty acids in the positionsn‐1, especially in phosphatidylethanolamines, that is important in determining the physical properties of biomembranes in relation to adaptational temperature.
Composition of phospholipids of white muscle of six tuna species
Authors: Medina Isabel , Aubourg Santiago P. , Martín Ricardo Pérez 
Published: November 2006

AbstractA comparative study of the phospholipids of white muscle of six of the comercially utilized tuna species, including quantitative analyses of phospholipid classes and studies of the acyl composition of the major components. Plasmalogen compounds also were identified and quantified. Choline and ethanolamine glycerophospholipids were the most abundant classes in all the samples, as well as the only molecules containing plasmalogens (16∶0, 18∶0, and 18∶1 alkenyl ether chains). The patterns of fatty acid distribution within each of the phospholipid classes showed general similarities in the species analyzed. However, ratios between certain saturated and polyunsaturated fatty acids in different phospholipid classes showed remarkable diffences. The high content of n−3 polyunsaturated fatty acids in the principal phospholipids, such as the plasmalogens, and taking into account the fatty acids possible importance in human nutrition, indicates that the white muscle of tuna species may be a potentially important dietary item.
Palmolein and groundnut oil have comparable effects on blood lipids and platelet aggregation in healthy Indian subjects
Authors: Ghafoorunissa  , Reddy Vinodini , Sesikaran B. 
Published: November 2006

AbstractSubstitution of palmolein (POL) for groundnut oil (GNO) doubles saturated fatty acids and decreases by half the linoleic acid (18∶2n−6) content of Indian diets. The effects of this substitution on selected parameters of cardiovascular risk and membrane functions were studied in middle‐aged subjects. Both metabolic (short‐term) and “in‐home” (long‐term) studies were conducted, and the subjects were crossed over from GNO to POL or vice versa. During both studies and in both sexes, blood pressure, plasma levels of total cholesterol and triglycerides and their distributions in various lipoprotein fractions were not altered. The lower 18∶2n−6 and higher 16∶0 intakes were reflected in fatty acid compositions of cholesteryl esters and triglycerides. However, the plasma and platelet phospholipid fatty acid patterns did not shift toward saturation. The observation that the levels of long‐chain polyunsaturated fatty acids in phospholipids were similar at the end of GNO and POL regimens indicates that 18∶2n−6 furnished during POL regimen may be sufficient to maintain the levels of arachidonic acid in cell membranes. Platelet aggregation, erythrocyte membrane fluidity, and activity of Na+,K+ ATPase, a membrane‐bound enzyme, were essentially similar at the end of the two oil regimens. These results indicate that POL is comparable to GNO and may not induce hypercholesterolemia in Indian subjects consuming cereal‐based diets containing 30% total fat calories and low cholesterol.
Arachidonic acid and eicosapentaenoic acid stimulate type II pneumocyte surfactant secretion
Authors: Baybutt Richard Carleton , Smith John Edgar , Gillespie Mark N. , Newcomb Terry G. , Yeh Yu‐Yan 
Published: November 2006

AbstractArachidonic acid and its leukotriene metabolites have been shown to stimulate surfactant secretion by alveolar type II cells. The present study was undertaken to determine the effects of various unsaturated fatty acids, including eicosapentaenoic acid, on surfactant secretion. Surfactant secretion was expressed as the percent of [3H]choline‐derived phospholipids released into culture medium by type II pneumocytes of adult rats. Consistent with the earlier findings, arachidonic acid stimulated secretion in a concentration‐dependent fashion (3.5–21 μM), doubling baseline secretion at 21 μM. Eicosapentaenoic acid was found to be equally effective as arachidonic acid in stimulating secretion. A comparison with palmitic, oleic and linoleic acids revealed that highly unsaturated fatty acids stimulated secretion to the greatest extent. This was supported by a positive correlation between degree of unsaturation (i.e., 0, 1, 2, 4 and 5 double bonds) and stimulation of surfactant secretion. In the present study, exogenous leukotriene E4 (10−13–10−6) did not stimulate surfactant secretion. Neither nordihydroguaiaretic acid (0.1μM) nor indomethacin (0.1μM) affected arachidonic acid‐stimulated secretion. The stimulatory effects of arachidonic acid and eicosapentaenoic acid on surfactant secretion were related to the highly unsaturated nature of the fatty acids and were not mediated by increased levels of cyclic adenosine monophosphate or calcium.
The lipid composition of selected tissues from a Mediterranean monk seal,Monachus monachus
Authors: Henderson R. James , Kalogeropoulos Nick , Alexis Maria N. 
Published: November 2006

AbstractThe lipid composition of blubber, brain, muscle and heart from a Mediterranean monk sealMonachus monachus (an endangered species) were examined to allow comparisons with more common species of seals. Only neutral lipids (mainly triacylglycerols) were detectable in the blubber lipids, whereas polar lipids predominated in the heart and in the brain. Neutral and polar lipids comprised almost equal proportions in both liver and muscle. Choline glycerophospholipids (CGP) were the major polar lipids, followed by ethanolamine glycerophospholipids (EGP) in the liver, heart and muscle. Cerebrosides accounted for 28.8% of the brain lipids. All lipid classes of the liver contained high levels (31–47%) of polyunsaturated fatty acids (PUFA), with the exception of phosphatidylserine. The total proportion of n−6 PUFA exceeded that of n−3 PUFA in all lipid classes of the liver, due mainly to the high levels of 20∶4n−6. The highest level of 20∶4n−6 occurred in phosphatidylinositol, where it comprised 32.4% of the total fatty acids. The CGP and EGP of the brain contained lower levels of PUFA than those of the liver, muscle and heart. Alkenyl ethers accounted for 35.8% of the total long‐chain moieties in brain EGP. The fatty acid composition of blubber triacylglycerols differed from those of the lipid classes from other tissues in that it had a very low ratio of n−6 to n−3 PUFA (0.3) as a result of a lower content of 20∶4n−6.
Comparison of the metabolism of α‐linolenic acid and its Δ6 desaturation product, stearidonic acid, in cultured NIH‐3T3 cells
Authors: Cantrill Richard C. , Huang Yung‐Sheng , Ells Gregory W. , Horrobin David F. 
Published: November 2006

AbstractThe incorporation and metabolism of α‐linolenic acid (18∶3n−3) and its Δ6 desaturase product, stearidonic acid (18∶4n−3), were compared by NIH‐3T3 cells. In the presence of fetal calf serum, cells accumulated exogenously added 18∶3n−3 and 18∶4n−3 apparently at the expense of oleic acid (18∶1n−9). Both 18∶3n−3 and 18∶4n−3 were elongated and desaturated to eicosatetraenoic acid (20∶4n−3), eicosapentaenoic acid (20∶5n−3) and docosapentaenoic acid (22∶5n−3), but not to docosahexaenoic acid (22∶6n−3), and were incorporated into phospholipids and triacylglycerols. Over a 4−d period, the growth of NIH‐3T3 cells was slightly stimulated in the presence of 18∶3n−3 (20 μg/mL) but was strongly inhibited in the presence of 18∶4n−3 at the same concentration. This inhibition may be caused by enhanced lipid peroxidation as a result of the high levels of 18∶4n−3 present.
The effect of culture medium composition on ether lipid cytotoxic activity
Authors: Diomede Luisa , Piovani Bianca , Modest Edward J. , Salmona Mario 
Published: November 2006

AbstractThe effect of a serum‐free medium (TNB‐100), compared to RPMI 1640 containing 10% fetal bovine serum (FBS), on the lipid composition of HL60 and K562 leukemic cells was investigated. The 10% FBS RPMI medium contained approximately three times more phospholipids (PL), about three times more protein and eight times more cholesterol (CHOL) than did the TNB‐100 medium. Cells cultured in TNB‐100 medium, referred to as HL60‐TNB and K562‐TNB cells, were significantly lower in PL and CHOL than 10% FBS RPMI cells, with about a threefold higher PL‐to‐CHOL ratio; however, these cells were significantly higher in protein content. Cells grown in TNB‐100 were also significantly more fluid than 10% FBS RPMI cells and were more sensitive to the fluidizing action of the ether lipid 1‐O‐octadecyl‐2‐O‐methyl‐rac‐glycero‐3‐phosphocholine. The 50% inhibitory dose of the drug was about 50% lower in TNB‐grown cells than in 10% FBS RPMI cells.
Synthesis of methyl 11,14,17‐eicosatrienoate‐3,3,4,4,8,8,9,9‐d8
Authors: Rakoff Henry 
Published: November 2006

AbstractFor use in metabolic studies, methyl 11,14,17‐eicosatrienoate‐3,3,4,4,8,8,9,9‐d8 was prepared by Wittig coupling of 3,6‐nonadienyltriphenylphosphonium iodide with methyl 11‐oxoundecanoate‐3,3,4,4,8,8,9,9‐d8 in the presence of butyl lithium. Theall cis isomer was separated by high‐pressure liquid chromatography using a reverse‐phase column. An unexpected by‐product, methyl 10,13,16‐nonadecatrienoate‐2,2,3,3,7,7,8,8‐d8, was also isolated. The structures and the configurations of the compounds were confirmed by nuclear magnetic resonance spectroscopy and mass spectrometry.
Rapid purification of rabbit reticulocyte lipoxygenase for electron paramagnetic spectroscopy characterization of the non‐heme iron
Authors: Carroll Richard T. , Muller Jessica , Grimm Jennifer , Dunham William R. , Sands Richard H. , Funk Max O. 
Published: November 2006

AbstractAn efficient three‐step purification technique has been developed for the reticulocyte 15‐lipoxygenase from rabbit. Ammonium sulfate fractionated reticulocyte lysate was purified by size exclusion chromatography and preparative scale isoelectric focusing. The entire procedure was complete in less than eight hours and was carried out in batches which typically yielded 10 mg of purified enzyme. The identity and purity of the enzyme were evaluated byN‐terminal sequencing, sodium dodecylsulfate polyacrylamide gel electrophoresis and specific activity determinations. The enzyme contained approximately one g‐atom iron per mole of protein. The iron was present in an electron paramagnetic spectroscopy (EPR) silent, presumably high spin iron(II), form in the isolated enzyme. Treatment with one equivalent of 13‐hydroperoxy‐9(Z),11(E)‐octadecadienoic acid resulted in the appearance of an EPR signal around g6.
A thermospray mass spectrometric assay for Fe‐induced 4‐hydroxynonenal in tissues
Authors: Blanchflower W. John , Walsh Dominic M. , Kennedy Seamus , Kennedy D. Glenn 
Published: November 2006

AbstractA method is presented for the determination of 4‐hydroxy‐nonenal (HNE) in tissue homogenates followingin vitro lipid peroxidation induced by iron (Fe++). NHE is measured as the pentafluorobenzyl oxime derivative using liquid chromatography thermospray mass spectrometry.In vitro metabolism of HNEvia the glutathione/glutathione‐S‐transferase pathway was inhibited using iodoacetic and iodobenzoic acids. The assay has been used as an indicator of the peroxidizability of tissue samples from animals both adequate in and depleted of α‐tocopherol. The concentrations of HNE produced in tissues taken from animals depleted of α‐tocopherol were found to be up to 8 times higher than those taken from animals supplemented with α‐tocopherol.
The effects of clofibrate and bezafibrate on cholesterol metabolism in the liver of the male rat
Authors: Shand J. H. , West D. W. 
Published: November 2006

AbstractFibric acid derivatives are used to treat hyperlipidemia and have wide ranging effects on lipid metabolism. The action of these compounds on cholesterol esterification, catalyzed by acyl‐coenzyme A:cholesterol acyltransferase (ACAT), has been quite widely studied, but their effect on cholesteryl ester hydrolysis and the enzyme neutral cholesteryl ester hydrolase (nCEH) has been largely ignored. Male rats were therefore fed for 10 d on a standard chow diet supplemented with either clofibrate or bezafibrate, to study their effects on plasma lipid levels and hepatic cholesterol metabolism. Plasma triacyglycerols were not significantly altered by these diets, but bezafibrate significantly lowered plasma cholesterol levels (29.7%,P<0.01). When expressed per unit weight of DNA, both fibrates reduced the hepatic content of triacylglycerol, cholesterol and cholesteryl esters (40, 18.7, 16.5 and 66.7, 28.6, 34.2% for clofibrate and bezafibrate, respectively). ACAT activity was significantly reduced by both drugs, but clofibrate (65% inhibition) was more effective than bezafibrate (35% inhibition). The most dramatic effect of the diets was a marked increase in the activity of both the microsomal and the cytosolic nCEH. When expressed on a whole liver basis, the effect of bezafibrate on the cytosolic enzyme (13.6‐fold increase in activity) was much greater than that of clofibrate (4.8‐fold increase). Increases in the activity of a cytosolic protein that inhibits the activity of nCEH were also noted, but these changes were relatively small. The results suggest that the activation of nCEH, in combination with the inhibition in ACAT activity, contributes to a decrease in the cholesteryl ester content of the liver which may influence the secretion of very low density lipoprotein.
Absorption of isomeric, palmitic acid‐containing triacylglycerols resembling human milk fat in the adult rat
Authors: de Fouw Nanneke J. , Kivits Gerard A. A. , Quinlan Paul T. , van Nielen Wim G. L. 
Published: November 2006

AbstractThe effect of the positional distribution of palmitic acid (16∶0) in triacylglycerols (TAG) on 16∶0 apparent absorption in adult rats was investigated. The rats were fed two diets which contained 30 energy % as fat with identical total fatty acid compositions, both containing 30% 16∶0. The Betapol diet contained TAG with 73% of total 16∶0 in thesn‐2 position, the control diet contained TAG with 6% of total 16∶0 in thesn‐2 position. After six weeks on these diets, the rats were killed two or six hours after the last meal, and the small intestine was removed, cut into 10‐cm segments, and the fatty acid composition of the segment's contents was determined. At both time points the amount of 16∶0 in the intestinal segments starting at 40 cm from the stomach was much lower in the animals fed Betapol than in the animals fed the control diet. Overall absorption of 16∶0 and stearic acid was significantly greater in the Betapol group. Absorption of oleic and linoleic acid from the small intestine was similar in both groups, although the overall absorption was significantly greater in the animals fed Betapol. Total fat absorption was significantly higher in the Betapol‐fed rats than in the control‐fed rats. No effect on calcium and nitrogen absorption, on plasma total cholesterol and TAG levels, and on bodyweights (growth) was seen. The data demonstrate that the positional distribution of the fatty acids in the TAG molecule affects the site of absorption in the small intestine and particularly the net absorption of saturated fatty acids.