bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of a 13C tracer to investigate lutein as a ligand for plasma transthyretin in humans
Authors: Chen Liwei , Collins Xixuan Hu , Tabatabai Louisa B. , White Wendy S. 
Published: November 2006

AbstractThe selective accumulation of lutein in the macula of the human retina is likely to be mediated by specific transport and/or binding proteins. Our objective was to determine whether transthyretin (TTR) is a plasma transport protein for lutein. We used a biosynthetic 13C‐lutein tracer and GC‐combustion interfaced‐isotope ratio MS to gain the requisite sensitivity to detect the minute amounts of lutein expected as a physiological ligand for TTR. Subjects (n=4) each ingested 1 mg of 13C‐lutein daily for 3 d and donated blood 24 h after the final dose. For three subjects, the plasma TTR‐retinol‐binding protein (RBP) complex was partially purified by anion‐exchange (diethylaminoethyl, DEAE) chromatography and then dissociated by hydrophobic‐interaction chromatography to yield the TTR component. For subject 4, the initial DEAE purification step was omitted and total plsma TTR (RBP‐bound and free) was isolated by hydrophobic‐interaction chromatography. In each case, the crude TTR fractions were then purified to homogeneity by RBP‐sepharose affinity chromatography. Pure TTR was extracted with chloroform, and unlabeled lutein was added to the extract as a carrier. The mean 13C/12C ratio (expressed in delta notation, δ13C) of the lutein fraction isolated from the plasma TTR extracts of the four subjects was −30.53±3.29‰. The δ13C value of the unlabeled lutein carrier was −30.97±0.27‰. Thus, no 13C enrichment was detected in association with TTR. We conclude that lutein is not associated with TTR in human plasma after being ingested in physiological amounts.
1H and 13C NMR characterization and stereochemical assignments of bile acids in aqueous media
Authors: Ijare Omkar B. , Somashekar B. S. , Jadegoud Y. , Nagana Gowda G. A. 
Published: November 2006

AbstractThe unconjugated bile acids cholic acid, deoxycholic acid, and chenodeoxycholic acid; their glycine and taurine conjugated glycocholic acid, glycodeoxycholic acid, glycochenodeoxycholic acid, taurocholic acid, taurodeoxycholic acid, and taurochenodeoxycholic acid; and a taurine conjugated ursodeoxycholic acid, tauroursodeoxycholic acid, were characterized through 1H and 13C NMR in aqueous media under the physiological pH region (7.4±0.1). Assignments of 1H and 13C signals of all the bile acids were made using a combination of several one‐ and two‐dimensional, homonuclear (1H−1H) and heteronuclear (1H−13C) correlations as well as spectral editing NMR methods. Stereochemical assignment of the five‐membered ring of the bile acids is reported here for the first time. The complete characterization of various bile acids in aqueous media presented here may have implications in the study of the pathophysiology of biliary diseases through human biliary fluids using NMR spectroscopy.
Lipid malabsorption persists after weaning in rats whose dams were given GLP‐2 and dexamethasone
Authors: Iordache Claudiu , Drozdowski Laurie A. , Clandinin M. Tom , Wild Gary , Todd Zoe , Thomson Alan B. R. 
Published: November 2006

AbstractGlucagon‐like peptide‐2 (GLP‐2) enhances intestinal growth and absorption in mature animals, and glucocorticosteroids (GC) increase the sugar and lipid uptake in adult animals. However, the role of GC and GLP‐2 in the ontogeny of lipid absorption is unknown. We hypothesized that GLP‐2 and the GC dexamethasone (DEX), when administrated to rat dams during pregnancy and lactation, would enhance lipid uptake in the off‐spring. Rat dams were treated in the last 10 d of pregnancy and during lactation with GLP‐2 [0.1 μg/g/d subcutaneous (sc)], DEX (0.128 μg/g/d sc), GLP‐2+DEX, or a placebo. Sucklings were sacrificed at 19–21 d of age, and weanlings were sacrificed 4 wk later. Lipid uptake was assessed using an in vitro ring uptake method. Although DEX and GLP‐2+DEX increased the jejunal mass, the jejunal lipid uptake was unchanged. In contrast, GLP‐2, DEX, and GLP‐2+DEX reduced the ileal lipid uptake in suckling and weanling rats. This reduction was not due to alterations in intestinal morphology or to changes in fatty acid‐binding protein abundance, but it was partially explained by an increase in the effective resistance of the intestinal unstirred water layer. In sucklings, DEX dramatically reduced the jejunal lipid uptake to levels similar to those seen in weanlings, such that the normal ontogenic decline in lipid uptake was not observed. Giving dams GLP‐2 or DEX during pregnancy and lactation reduced lipid uptake in the offspring, and this persisted for at least 1 mon. The impact this may have on the nutritional well‐being of the animal in later life is unknown.
Effect of dietary n−6 and n−3 polyunsaturated fatty acids on peroxidizability of lipoproteins in steers
Authors: Scislowski Valérie , Bauchart Dominique , Gruffat Dominique , Laplaud Paul‐Michel , Durand Denys 
Published: November 2006

AbstractThe susceptibility of major plasma lipoproteins to lipoperoxidation was studied in relation to the FA composition of their neutral and polar lipids in steers given PUFA‐rich diets. Two trials used, respectively, 18 (“sunflower” experiment, S) or 24 (“linseed” experiment, L) crossbred Salers x Charolais steers. Each involved three dietary treatments over a 70‐d period: a control diet (CS or CL diets) consisting of hay and concentrate, or the same diet supplemented with oilseeds (4% diet dry matter) fed either as seeds (SS or LS diets) or continuously infused into the duodenum (ISO or ILO diets). Compared with control diets, ISO and ILO treatments tended to decrease the resistance time of LDL and HDL classes to peroxidation, mainly owing to the enrichment of their polar and neutral lipids with PUFA. With diets SS and LS, sensitivity of major lipoprotein classes (LDL, light and heavy HDL) was not affected because ruminal hydrogenation of dietary PUFA decreased their incorporation into lipoparticles. ISO and ILO treatments induced a more important production of conjugated dienes and hydroperoxides generated by peroxidation in the three lipoprotein classes due to the higher amounts of PUFA esterified in lipids of the core and the hydrophilic envelope of particles. The production of malondialdehyde (MDA) increased in steers fed linseed supplements, indicating that MDA production did not occur with linoleic acid provided by sunflower oil supplements. Thus, plasma peroxidation of PUFA generates toxic products in steers fed diets supplemented with PUFA and can be deleterious for the health of the animal during long‐term treatment.
Supplementation with a pine bark extract rich in polyphenols increases plasma antioxidant capacity and alters the plasma lipoprotein profile
Authors: Devaraj Sridevi , Vega‐López Sonia , Kaul Nalini , Schönlau Frank , Rohdewald Peter , Jialal Ishwarlal 
Published: November 2006

AbstractPycnogenol® (PYC), an extract of French maritime pine bark (Pinus pinaster), is a potent antioxidant with potential health benefits. Its bioavailabilty has previously been shown by urinary excretion studies of constituents and metabolites of PYC. The aim of this study was to test the effect of PYC supplementation on measures of oxidative stress and the lipid profile in humans. Twenty‐five healthy subjects received PYC (150 mg/d) for 6 wk. Fasting blood was collected at baseline, after 3 and 6 wk of supplementation, and again after a 4‐wk washout period. After 6 wk of supplementation with PYC, a significant increase in plasma polyphenol levels was detectable, which was reversed after the 4‐wk washout phase. The antioxidant effect of PYC was demonstrated by a significant increase in oxygen radical absorbance capacity (ORAC) in plasma throughout the supplementation period (P<0.05). The ORAC value returned to baseline after the 4‐wk washout period. Moreover, in addition to its antioxidant effects, PYC significantly reduced LDL‐cholesterol levels and increased HDL‐cholesterol levels in plasma of two‐thirds of the subjects. While the LDL changes reversed during washout, the HDL increase did not. There was no significant difference in LDL oxidizability or plasma lipid peroxides following PYC supplementation. Hence, following oral supplementation in humans, PYC significantly increases antioxidant capacity of plasma, as determined by ORAC, and exerts favorable effects on the lipid profile.
EPA, but not DHA, decreases mean platelet volume in normal subjects
Authors: Park Yongsoon , Harris William 
Published: November 2006

AbstractThe first indication of platelet activation is an increase in mean platelet volume (MPV). n−3 FA are known to inhibit platelet function and to reduce the risk for coronary heart disease. The purpose of this study was to determine the effects of FPA and DHA on MPV. Healthy subjects received olive oil placebo for 4 wk and then were randomly assigned to receive 4g of ethyl esters of either safflower oil (n=11), EPA (n=10), or DHA (n=12) for 4 wk. At the end of placebo run‐in and treatment periods, MPV (fL; mean±SEM) and platelet count (PLT‐CT; 103/μL blood) were measured in the basal state and after ex vivo stimulation with collagen (10 μg/mL), cold (4°C), and heat (37°C). Unlike DHA, EPA lowered MPV as compared with safflower oil (7.2±0.1 vs. 7.5±0.1 fL; P<0.05) and raised PLT‐CT (211±18 vs. 192±18 103/μL; P<0.05) in the fasting state. Collagen and cold significantly increased MPV whereas heat lowered MPV regardless of treatment. All stimuli decreased PLT‐CT. EPA significantly increased platelet EPA (0.2±0.1 vs. 3.3±0.4%) and docosapentaenoic acid (DPA; 2.2±0.3 vs. 2.9±0.3%) concentrations, but not DHA. DHA treatment significantly increased DHA (1.4±0.2 vs. 4.1±0.5%) and DPA (2.0±0.4 vs. 3.0±0.4%) concentrations, but not EPA. In conclusion, EPA, but not DHA, reduces platelet activation, an early step in platelet aggregation.
Alterations of the lipid profile after 7.5 years of low‐dose antioxidant supplementation in the SU.VI.MAX study
Authors: Hercberg Serge , Bertrais Sandrine , Czernichow Sébastien , Noisette Nathalie , Galan Pilar , Jaouen Adèle , Tichet Jean , Briancon Serge , Favier Alain , Mennen Louise , Roussel Anne‐Marie 
Published: November 2006

AbstractAntioxidant micronutrients have been reported to be associated with an improvement in the blood profile, but the results are not consistent. The aim of the present study was to assess the effects of antioxidant supplementation on changes in the serum lipid profile of adult participants in the SU.VI.MAX study. French adults (n=12,741∶7,713 females aged 35–60 yr, and 5,028 males aged 45–60 yr) received daily antioxidant supplementation (120 mg vitamin C, 30 mg vitamin E, 6 mg β‐carotene, 100 μg selenium, and 20 mg zinc) or a matching placebo. Median follow‐up time was 7.5 yr. After 7.5 yr, no effect of supplementation on total cholesterol was observed in men or women after adjusting for baseline total cholesterol levels and lipid‐lowering medications. The prevalence of hypercholesterolemia (≥6.5 mmol/L) showed a trend toward being higher in women who received supplements compared with those who received the placebo (P=0.06). In both sexes, the group receiving supplements exhibited higher mean serum TG concentrations than did the placebo group (P=0.06 in men; P=0.05 in women). The prevalence of hypertriglyceridemia (≥2.3 mmol/L) was also significantly higher in men who received supplements (P=0.03), but not in women. Our results suggest than long‐term daily supplementation with low doses of β‐carotene, vitamins C and E, selenium, and zinc does not result in an improved lipid profile and could even adversely affect some blood lipids, possibly with a higher risk of hyperlipidemia in women.
Metal‐lon stimulation and inhibition of lysophospholipase D which generates bioactive lysophosphatidic acid in rat plasma
Authors: Tokumura Akira , Miyake Maki , Yoshimoto Osamu , Shimizu Mayumi , Fukuzawa Kenji 
Published: November 2006

AbstractWe found that lysophospholipase D (LPLD) in rat plasma prefers unsaturated to saturated lysophosphatidylcholines as substrates, generating a biologically active lipid, lysophosphatidic acid, but it does not hydrolyze diacyl‐phospholipids. In this study, this LPLD required a metal ion for activity, Co2+ being the most effective, followed in order by Zn2+, Mn2+, and Ni2+. This metal‐ion‐stimulated LPLD with unique substrate specificity, which has not been described previously, was susceptible to thiol‐blocking reagents and serine esterase inhibitors, but not to a histidine‐modifying reagent. Consistent with results using thiol‐modifying agents, short‐chain fatty aldehydes, secondary products of lipid peroxidation, were found to inhibit LPLD. Addition of dibutylhydroxytoluene or butylhydroxyanisole to the plasma increased the activity of this enzyme, probably in a manner independent of its antioxidant activity, since another antioxidant, propyl gallate, was rather inhibitory. These results suggest that rat plasma contains an active LPLD that differs in some properties from other members of the known phospholipase D family detected in animal tissues and body fluids.
Lipid and fatty acid composition of different fractions from rat urinary transitional epithelium
Authors: Calderon Reyna O. , Glocker Monica , Eynard Aldo R. 
Published: November 2006

AbstractThe phospholipid composition of rat urinary transitional epithelium (TE) and the fatty acid composition of microsomal, mitochondrial, cytosolic, and plasma membrane (PM) subcellular fractions were investigated. PM marker enzymes and electron microscopy analysis were used to characterize the PM fraction, which showed a distinctive lipid composition compared to the general profile of PM from different sources. The levels of cholesterol and sphingomyelin were not enriched in the PM fraction; on the other hand, the increased amounts of glycosphingolipids and phosphatidylserine, and the decreased level of phosphatidylcholine followed the general features of a PM profile. This differential PM lipid composition may reflect the unique morphology of this mammal TE, consisting of concave plaques with an asymmetrical membrane unit. The distribution of the double bond across the PM indicated a higher unsaturation of the inner relative to the outer part of the PM hemileaflet. In addition, the presence of 20∶3n−9 nonessential fatty acid in a normal TE may represent a characteristic fatty acid metabolism of this epithelium.
Obesity as a risk factor for certain types of cancer
Authors: Carroll K. K. 
Published: November 2006

Summary and ConclusionsIn conclusion, obesity has been associated with increased risk for a number of different types of cancer. The evidence has been most consistent for endometrial cancer, breast cancer in postmenopausal women, and renal cell cancer. More variable results have been reported for colorectal, prostate and pancreatic cancer.Possible mechanisms by which obesity may influence cancer risk include alteration in hormonal patterns, including sex hormones and insulin, and factors such as the distribution of body fat and changes in adiposity at different ages. The increasing prevalence of obesity in many parts of the world emphasizes the importance of learning more about the relationship between obesity and cancer and the mechanisms involved in their interaction.
Surface pressure‐dependent cross‐modulation of sphingomyelinase and phospholipase A2 in monolayers
Authors: Fanani María Laura , Maggio Bruno 
Published: November 2006

AbstractWe investigated the ways in which phospholipase A2 and sphingomyelinase are mutually modulated at lipid interfaces. The activity of one enzyme is affected by its own reaction products and by substrates and products of the other enzyme; all this depends differently on the lateral surface pressure. Ceramide inhibits both the sphingomyelinase activity rate and the extent of degradation, and decreases the lag time at all surface pressures. Dilauroyl‐ and dipalmitoylphosphatidyl‐choline, the substrates of phospholipase A2 (PLA2), do not affect sphingomyelinase activity. The products of PLA2, palmitic acid and lysopalmitoylphosphatidylcholine, strongly enhance and shift to high surface pressures the activity optimum and the cut‐off point of sphingomyelinase. Palmitic acid also shifts to high surface pressures the cut‐off point of PLA2 activity. Sphingomyelin strongly inhibits PLA2 at surface pressures above 5 mN/m, while ceramide shifts the cut‐off point and the activity optimum to high surface pressures. The sphingolipids increase the lag time of PLA2 at low surface pressures. Both phosphohydrolytic pathways involve different levels of control on precatalytic steps and on the rate of activity that appear independent on specific alterations of molecular packing and surface potential. The mutual lipid‐mediated interfacial modulation between both phosphohydrolytic pathways indicates that phospholipid degradation may be self‐amplified or dampened depending on subtle changes of surface pressure and composition.
Low density lipoprotein of synovial fluid in inflammatory joint disease is mildly oxidized
Authors: James M. J. , van Reyk D. , Rye K. A. , Dean R. T. , Cleland L. G. , Barter P. J. , Jessup W. 
Published: November 2006

AbstractOxidatively modified low density lipoprotein (LDL) has many biological activities which could contribute to the pathology of the atherosclerotic lesion. Because atherosclerosis has an inflammatory component, there has been much interest in the extent to which LDL could be oxidatively modified in vivo by inflammation. The present study examined LDL present in an accessible inflammatory site, the inflamed synovial joint, for evidence of compositional change and oxidative modification. LDL was isolated from knee joint synovial fluid (SF) from subjects with inflammatory arthropathies and also from matched plasma samples. SF and plasma LDL had similar free cholesterol and α‐tocopherol content, but SF LDL had a lower content of esterified cholesterol. On electrophoresis, SF LDL was slightly more electronegative than LDL from matched plasma samples, but the changes were much less than those resulting from Cu2+‐treatment of LDL. Oxidized cholesterol was not detected in any samples, but cholesterol ester hydroperoxide levels were greater in SF than in plasma LDL. When samples from three subjects were incubated with macrophages, the SF LDL did not cause significant loading of the cells with cholesterol or cholesterol esters, in contrast to the situation with acetylated LDL. Overall, the SF LDL displayed evidence of slightly increased oxidation by comparison with matched plasma samples. Despite their isolation from an environment with active inflammation, changes were modest compared with those resulting from Cu2+ treatment. Thus, extensive LDL oxidation is not a necessary correlate of location in a chronic inflammatory site, even though it is characteristic of atherosclerotic lesions.
Lipid peroxidation of isolated chylomicrons and oxidative status in plasma after intake of highly purified eicosapentaenoic or docosahexaenoic acids
Authors: Hansen John‐Bjarne , Berge Rolf K. , Nordøy Arne , Bønaa Kaare H. 
Published: November 2006

AbstractFourteen healthy male volunteers were given two separate high‐saturated‐fat meals with and without the addition of 4 g highly purified ethyl esters of either eicosapentaenoic acid (EPA) (95% pure, n=7) or docosahexaenoic acid (DHA) (90% pure, n=7) supplied as 1‐g capsules each containing 3.4 mg vitamin F. The chylomicrons were isolated 6 h after the meals, at peak concentrations of n−3 fatty acids (FA). Addition of n−3 FA with the meal caused a 10.4‐fold increase in the concentration of n−3 FA in chylomicrons compared to the saturated fat meal without addition of n−3 FA. After the saturated‐fat meal, the concentration of thiobarbituric acid‐reactive substances (TBARS) was 327.6±34.6 nmol/mmol triacylglycerol (TAG), which increased to 1015.8±212.0 nmol/mmol TAG (P<0.0001, n=14) after EPA and DHA were added to the meal. There was no significant correlation between the concentrations of TBARS and vitamin E in the chylomicrons collected 6 h after the test meal. The present findings demonstrate an immediate increase in chylomicron peroxidation ex vivo provided by intake of highly purified n−3 FA. The capsular content of vitamin E was absorbed into chylomicrons, but the amount of vitamin E was apparently not sufficient to protect chylomicrons against lipid peroxidation ex vivo. Daily intake of 4 g n−3 FA either as EPA or DHA for 5 wk did not change the plasma concentration of TBARS. Although not significantly different between groups, DHA supplementation decreased total glutathione in plasma (P<0.05) and EPA supplementation increased plasma concentration of vitamin E (P<0.05). The other lipid‐soluble and polar antioxidants in plasma remained unchanged during 5 wk of intervention with highly purified n−3 FA.
Human SIRT1: A potential biomarker for tumorigenesis?
Authors: Lim Chang‐Su 
Published: November 2006

AbstractAccumulating body of evidence reveals that hSIRT1, an NAD+‐dependent protein deacetylase, is involved in regulating numerous biological processes. Therefore cellular functions of hSIRT1 are highly pleiotropic. The integrated hypothetical mechanisms of hSIRT1 action contributing to regulating cellular senescence and longevity have been proposed. Based on recent evidence, I propose that hSIRT1 is a potential biomarker for tumorigenesis.
Competing hydrogen-bonding patterns and phase transitions of 1,2-diaminoethane at varied temperature and pressure
Authors: Budzianowski Armand , Olejniczak Anna , Katrusiak Andrzej 
Published: November 2006

1,2-Diaminoethane has been in-situ pressure- and temperature-frozen; apart from two known low-temperature phases, Iα and II, three new phases, Iβ, Iγ and III, have been observed and their structures determined by X-ray diffraction. The measurements at 0.1 MPa were carried out at 274, 243 and 224 K, and 296 K measurements were made at 0.15 GPa (phase Iα), at 0.3 and 1.1 GPa (phase Iβ), at 1.5 GPa (phase Iγ), and at 0.2, 0.3 and 0.5 GPa (phase III). All these phases are monoclinic, space group P21/c, but the unit-cell dimension of phases Iα and III are very different at 296 K: a
Iα = 5.078 (5), b
Iα = 7.204 (8), c
Iα = 5.528 (20) Å, β
Iα = 115.2 (2)° at 0.15 GPa, and a
III = 5.10 (3), b
III = 5.212 (2), c
III = 7.262 (12) Å, β
III = 111.6 (4)° at 0.2 GPa, respectively; in both phases Z = 2. An ambient-pressure low-temperature phase II has been observed below 189 K. Discontinuities in the unit-cell dimensions and in the N...N distance mark the isostructural transition between phases Iα and Iβ at 0.2 GPa, which can be attributed to a damping process of the NH2 group rotations. In phase Iγ the unit-cell parameter a doubles and Z increases to 4. The molecule has inversion symmetry in all the structures determined. 1,2-Diaminoethane can be considered as a simple structural ice analogue, but with NH...N hydrogen bonds and with the H-atom donors (four in one molecule) in excess over H-atom acceptors (two per molecule). Thus, the transformations of 1,2-diaminoethane phases involving the conformational dynamics affect the hydrogen-bonding geometry and molecular association in the crystal. The 1,2-diaminoethane:1,2-dihydroxyethane mixture has been separated by pressure-freezing, and a solid 1,2-diaminoethane crystal in liquid 1,2-dihyroxyethane has been obtained.