bluuebunny/crossref_metadata_2025_split huggingface dataset:
Induction of geranyl pyrophosphate pyrophosphatase activity by cholesterol‐suppressive isoprenoids
Authors: Case Gary L. , He Lei , Mo Huanbiao , Elson Charles E. 
Published: November 2006

AbstractDiets supplemented (1 mmol/kg) with thymol, carvacrol, and β‐ionone significantly decreased the serum cholesterol levels of cockerels. These mevalonate‐derived end products of plant secondary metabolism (isoprenoids) had no impact on two cytosolic prenyl alcohol (and ethanol) dehydrogenase activities; each treatment increased microsomal geranyl pyrophosphate pyrophosphatase activity by greater than twofold. The structural diversity of the isoprenoids which suppress cholesterol synthesis may be reconciled by their ability to increase pyrophosphatase activity, thus leading to the production of the endogenous, post‐transcriptional regulator of 3‐hydroxy‐3‐methyglutaryl coenzyme A reductase activity.
Effects of pregnenolone‐16α‐carbonitrile on the metabolism of cholesterol in rat liver microsomes
Authors: Ståhlberg Dagny 
Published: November 2006

AbstractThe effects of pregnenolone‐16α‐carbonitrile (PCN) on hepatic metabolism of cholesterol were studied in rat liver microsomes in order to clarify the underlying mechanisms of the PCN‐induced biliary hypersecretion of cholesterol. Male Sprague‐Dawley rats were fed a diet supplemented with 0.05% of PCN for one week. The microsomal activity of 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase, regulating cholesterol biosynthesis, decreased from 577 ± 46 (SEM) to 367 ± 38 pmol/min/mg protein compared to the controls. Cholesterol 7 α‐hydroxylase activity, governing bile acid synthesis, was 9.0 ± 1.1 pmol/min/mg protein in the treated group and 34.8 ± 7.4 pmol/min/mg protein in the controls, a reduction of 74% (P<0.01). The acyl CoA:cholesterol acyltransferase (ACAT) activity, catalyzing the esterification of cholesterol, remained unchanged, as did the levels of total and free cholesterol in liver homogenates and microsomes. The results of this study provide evidence that the increase in biliary cholesterol secretion during PCN treatment is not caused by a change in ACAT activity, but can be explained by a decreased catabolism of cholesterol to bile acids.
Lipid biosynthesis in cultured arterial smooth muscle cells is related to their phenotype
Authors: Dusserre Eric , Bourdillon Marie‐Claude , Ciavatti Maryvonne , Covacho Chantal , Renaud Serge 
Published: November 2006

AbstractDuring the atherogenic processin vivo, arterial smooth muscle cells (SMC) undergo changes in their phenotype. In the present study, rat SMC from primary cultures and from subcultures before 10 and after 200 passages, showing contractile‐like, synthetic and transformed phenotypes, respectively, were compared in regard to their lipid content and biosynthesis. The rationale for comparing these phenotypes rests in the similar changes in phenotype of SMC that occur in the formation and progression of atherosclerotic lesions. Phenotype changes were shown to be associated with changes in the phospholipid content of SMC. Phospholipid levels increased, but not as significantly as did cholesterol levels when passing from contractile to synthetic and transformed cells (1.23±0.18, 2.28±0.26 and 3.25±0.23 μg/106 cells, respectively). Cholesterol normalized in respect to cell protein was increased to the same extent. Lipid synthesis as judged by [14C]acetate incorporation was increased 3‐ to 12‐fold in the synthetic and transformed cells, respectively, compared to contractile cells. After thin‐layer chromatography, radioactivity was shown to be markedly increased in most of the lipid fractions, but label in the cholesterol fraction of synthetic and transformed cells was increased by 7‐ and 21‐fold, respectively. Thus, SMCin vitro were shown to drastically increase cholesterol biosynthesis associated with phenotype changes. Such changes are known to occurin vivo and might represent a critical step in the deposition of excess cholesterol within foam cells.
The esterified plasma fatty acid profile is altered in early HIV‐1 infection
Authors: Peck Michael D. , Mantero‐Atienza Emilio , Miguez‐Burbano Maria Jose , Fletcher Mary Ann , Shor‐Posner Gail , Baum Marianna K. 
Published: November 2006

AbstractPrevious studies have shown that alterations in micronutrient utilization occur in patients with Acquired Immune Deficiency Syndrome. In this study, total plasma fatty acid composition was measured in 36 homosexual men infected with the Human Immunodeficiency Virus 1 (HIV‐1) and in 17 HIV‐1 seronegative homosexual men in order to evaluate differences associated with early HIV‐1 infection. Immunologic assessment included CD4 cell number count and lymphocyte blastogenesis in response to the mitogens phytohemagglutinin (PHA) and pokeweed (PWM). The mean total amount of ω6 polyunsaturated fatty acids (18∶2 and 20∶4) was significantly lower in the HIV‐1 seropositive subjects (38±8.1% SD) as compared to HIV‐1 seronegative subjects (43±4.2%;P=0.0027). This was also reflected in a higher level of total saturated fatty acids (16∶0 and 18∶0) in HIV‐1 seropositive subjects (30±2.2%vs. 26±2.8%;P=0.0001). The ratio of linoleic to arachidonic acid (18∶2 to 20∶4) was higher in the HIV‐1 seronegative group (6.76±4.88) compared to the HIV‐1 seronegative group (4.86±1.37;P=0.0213). The response to PHA in seropositive subjects correlated inversely with total plasma ω6 fatty acids (r=−0.36;P=0.027), and directly with the 18∶2 to 20∶4 ratio (r=0.33;P=0.046). CD4 cell counts and the response to PWM did not correlate with plasma fatty acid levels in HIV‐1 seropositive subjects. We conclude that early HIV‐1 infection is associated with lower plasma ω6 polyunsaturated fatty acids, notably arachidonic acid, than are controls, and that the changes in the plasma fatty acid profile correlate with some indices of immune function.
Adipose glycerolipid formation: Effect of nutritional and hormonal states
Authors: Jamdar Subhash C. , Cao Wang Fang 
Published: November 2006

AbstractThe potential of glycerolipid formation fromsn‐glycerol‐3‐phosphate (GP) and 2‐monoacylglycerol (MG) was studied in adipose microsomal fractions under various nutritional and hormonal states. Glycerolipid formation from GP was followed in the presence of [14C]glycerol‐3‐phosphate and palmitoyl‐CoA and was assayed by measuring the formation of butanol‐soluble product, consisting mainly of [14C]phosphatidate. Glycerolipid formation from MG was determined in the presence of 2‐monooleyl glycerol and [14C]palmitoyl‐CoA, and was estimated by the formation of both [14C]di‐ and triacylglycerol. Glycerolipid formation from GP was decreased significantly during food deprivation, in experimental diabetes, in the presence of lipolytic hormone, and during aging. Glycerolipid formation from MG did not change under these conditions and continued at the same rate as observed in control animals. The rate of glycerolipid formation from GP was 7–20 times greater than from MG in the various fat depots. Measurement of the adipose mono‐acylglycerol concentration did not show any correlation with the glycerolipid formation from MG. The studies suggest that glycerolipid formation from MG is active in various fat depots, and is substantial when glycerolipid formationvia GP is impaired.
Nervonic acid in red blood cell sphingomyelin in premature infants: An index of myelin maturation?
Authors: Babin F. , Sarda P. , Limasset B. , Descomps B. , Rieu D. , Mendy F. , Crastes de Paulet A. 
Published: November 2006

AbstractThe present study addresses the question whether nervonic acid (24∶1n−9) accumulation in sphingomyelin (SM) of red blood cells (RBC) could yield information on cerebrum maturation in premature infants. The study included 28 premature eutrophic infants of 31.5 wk gestational age. Eleven were fed with human milk, nine with a regulator formula and eight with an α‐linolenate‐enriched formula. The fatty acid composition of the SM fraction was determined by gas‐liquid chromatography on a 50‐m fused silica capillary column. At 32 wk gestational age, the main fatty acids in SM were 16∶0, 18∶0, 20∶0, 22∶0, 24∶0 and 24∶1n−9. After five weeks of feeding, at week 37 of postconceptional age, the most striking variation was a rise in 24∶1n−9, from 9.9±0.7 to 12.8±0.9 (P<0.02), regardless of regimen in all three feeding groups. The rise in 24∶1n−9 after birth in premature eutrophic infants is the beginning of a trend toward the higher levels in 24∶1n−9 observed in mature newborns and older infants. The 24∶1n−9 level in SM of RBC from premature infants may reflect 24∶1n−9 levels in SM of brain and could thus reflect brain maturity.
Phospholipid molecular species from human placenta lipids
Authors: Bayon Y. , Croset M. , Chirouze V. , Tayot J. L. , Lagarde M. 
Published: November 2006

AbstractThe phospholipid molecular species from a large‐scale preparation of human placenta lipids were analyzed. The major placental phospholipids were choline glycerophospholipids (CPL) (53.2 wt%), sphingomyelin (21.7 wt%) and ethanolamine glycerophospholipids (EPL) (14.6 wt%). 1,2‐Diacyl‐glycerophosphocholine was the most abundant subclass of CPL (91.7 mol%), while EPL contained 1,2‐diacyl (54.6 mol%) and 1‐alk‐1′‐enyl‐2‐acyl (43.8 mol%) subclasses. The level of polyunsaturated fatty acids (PUFA) in total phospholipids was remarkably constant (38.4–39.9 mol%) within all placental batches tested. The long‐chain PUFA, mainly 20∶4n−6 and 22∶6n−3 of the n−6 and n−3 series, respectively, were found in high proportion in all phospholipid classes, especially in EPL (46.7 mol%) and in inositol glycerophospholipids (IPL) (39.9 mol%). CPL and serine glycerophospholipids were much richer in 18∶1n−9 and 18∶2n−6. High levels of molecular species with arachidonic acid in thesn‐2 position were found particularly in 1‐alk‐1′‐enyl‐2‐acyl‐glycerophospho‐ethanolamine (with 24.0 mol% 16∶0 and 22.0 mol% 18∶0 insn‐1 position) and in 1,2‐diacyl glycerophosphoinositol with 42.6 mol% 18∶0 insn‐1 position. EPL subclasses were rich in 22∶6n−3, which occurs mainly as 16∶0/22∶6n−3 (11.7 mol%) in the polasmalogen form and as 18∶0/22∶6n−3, 16∶0/22∶6n−3 and 18∶1/22∶6n−3 in the diacyl forms. Based on their availability and composition, placental phospholipids could be of interest, for example, for supplementing artificial milk preparations with n−3 and n−6 long‐chain PUFA for newborn infants with insufficiently developed 18∶2n−6 and 18∶3n−3 desaturation/elongation.
Dietary fat effects on hepatic lipid peroxidation and enzymes of H2O2 metabolism and NADPH Generation
Authors: Chen Li‐Chuan , Boissonneault Gilbert , Hayek Michael G. , Chow Ching K. 
Published: November 2006

AbstractThe purpose of this study was to determine the effects of dietary fat quantity and fatty acid composition on hepatic H2O2‐metabolizing systems, activities of NADPH‐generating enzymes and lipid peroxidation. Onemonth‐old male C57BL/6J mice were fed one of six diets: (i) 5% fat, rich in 18∶2n−6 fatty acid (5% N−6); (ii) 20% fat, rich in 18∶3n−3 (N−3); (iii) 20% fat, rich in 18∶2n−6 (N−6); (iv) 20% fat, rich in 18∶1n−9 (N−9); (v) 20% fat, rich in saturated fatty acids (SAT); and (vi) 20% fat, deficient in essential fatty acids (EFAD); for 11 wk. Comparisons between animal groups receiving different fat quantities showed that activities of glucose‐6‐phosphate dehydrogenase (G6PDH, EC 1.1.1.49) and malic enzyme (ME, EC 1.1.1.40) and the levels of conjugated dienes were significantly lower in the N−6 than in 5% N−6 group. Conversely, activities of catalase (CAT, EC 1.11.1.6) and seleniumglutathione peroxidase (SeGSHPx, EC 1.11.1.9) were higher in the N−6 than in 5% N−6 group. Among the five dietary groups receiving 20% fat but differing in fatty acid composition, CAT activity was lower in the N−9 group, SeGSHPx activity was lower in the EFAD group, and glutathione reductase (GSSGR, EC 1.6.4.2) activity was higher in the N−6 than in the N−3, N−9, SAT and EFAD groups. The EFAD group had much higher levels of total lipids and conjugated dienes, as well as activities of NADPH‐generating enzymes, including G6PDH, ME and isocitrate dehydrogenase (EC 1.1.1.42), than the other four high‐fat groups. The hepatic levels of malondialdehyde were not different among the five groups fed 20% fat. In the EFAD group, higher hepatic lipid content can be attributed to higher activities of NADPH‐generating enzymes, and the elevation of conjugated diene levels may be related to increased oxygenation of 20∶−6 (Mead acid)via the lipoxygenase/cyclooxygenase pathway. In short, both dietary fat quantity and fatty acid composition selectively affected hepatic H2O2‐metabolizing systems, activities of NADPH‐generating enzymes and lipid peroxidation status.
Diabetes increases excretion of urinary malonaldehyde conjugates in rats
Authors: Gallaher Daniel D. , Csallany A. Saari , Shoeman Don W. , Olson Judith M. 
Published: November 2006

AbstractThe effect of streptozotocin‐induced diabetes on the urinary excretion of thiobarbituric acid test‐positive materials was examined. In diabetic rats, urinary excretion of thiobarbituric acid reactive substances was increased 5‐fold over that in nondiabetic animals. High‐performance liquid chromatography of urine samples revealed that five of the six fractions previously found to be increased in vitamin E deficiency [Lee, H.‐S., Shoeman, D.W., and Csallany, A.S. (1992)Lipids 27, 124–128] were also significantly increased in streptozotocin‐induced diabetes. The data suggest that a high level of oxidative stress is induced by uncontrolled diabetes in rats.
Fatty acid composition of brain phospholipids in aging and in Alzheimer’s disease
Authors: Söderberg M. , Edlund C. , Kristensson K. , Dallner G. 
Published: November 2006

AbstractThe two major phospholipid classes, namely, phosphatidylethanolamines (PE) and phosphatidylcholines (PC), were studied in four different regions of human brain,i.e., in frontal gray matter, frontal white matter, hippocampus and in pons. The fatty acid (FA) compositions of these phospholipids were found to be specific for the different regions. PC contains mostly saturated and 18∶1 FA, while PE is rich in polyunsaturated FA. Aging has no influence on the FA compositions, while in Alzheimer’s disease (AD) PE is modified in all four regions, particularly in frontal gray matter and in hippocampus. The abundance of the major monounsaturated FA of PE, 18∶1, is not significantly altered in Alzheimer’s disease, but there is a substantial increase in the relative amounts of the saturated components 14∶0, 16∶0 and 18∶0. This is paralleled by a decrease in the polyunsaturated FA 20∶4, 22∶4 and 22∶6. It is not clear whether the changes observed are specific for AD. Changes in saturated/polyunsaturated FA ratio are likely to influence cellular function, which in turn may cause certain neural deficiencies. The findings do not support the hypothesis that AD reflects an accelerated aging process.
Study on the lipid composition of aging fischer‐344 rat lymphoid cells: Effect of long‐term calorie restriction
Authors: Laganiere Serge , Fernandes Gabriel 
Published: November 2006

AbstractLong‐term calorie restriction (LCR) is widely known to increase the survival rate of laboratory rodents and appears to retard the aging and senescence process. The present study was undertaken in Fischer‐344 male rats maintained onad libitum (AL) or LCR (40% less food intake than AL starting at 6 weeks of age). Age‐associated changes in the proliferative response of lymphoid cells to mitogenic stimuli were studied in relation to alterations in the fatty acid composition of adherent and nonadherent‐enriched subpopulations of spleen cells. Increases in spleen cell long‐chain highly unsaturated fatty acids (20∶4, 22∶4 and 22∶5) were accompanied by decreases in linoleic acid (18∶2) in aging AL‐fed rats. However, LCR stabilized levels of 18∶2 and prevented the rise in highly unsaturated fatty acids. In addition, LCR markedly modulated the fatty acid profiles of thymocytes and bone marrow cells. A 70% decline in concanavalin A (Con A) stimulated [3H]thymidine uptake of spleen cells from AL animals was normalized by LCR. Splenic reduced glutathione (GSH), a potential modulator of the mitogenic response, was unaffected by age and nutritional regimen. Thus, normalization of lymphoid cell fatty acid composition by LCR parallels the preservation of mitogenic responsiveness to Con A.
Protein kinase C‐dependent stimulation of phospholipase D in phospholipase C‐treated fibroblasts
Authors: Kiss Zoltan , Garamszegi Nandor 
Published: November 2006

AbstractTreatment of [14C]choline‐ or [14C]ethanolamine‐labeled NIH 3T3 fibroblasts withBacillus cereus phosphatidylcholine‐specific phospholipase C (PLC) enhanced phospholipase D (PLD)‐mediated hydrolysis of the respective14C‐labeled phospholipids. PLD activity was stimulated by 1.5 U/mL of POLC and by 100 nM of the protein kinase C (PKC) activator phorbol 12‐myristate 13‐acetate (PMA) to similar extents. Treatment of14C]palmitic acid‐labeled fibroblasts with PLC in the presence of ethanol also enhanced PLD‐mediated formation of phosphatidylethanol; the effects of PLC and PMA were nonadditive. PLC had no effect on PLD activity in fibroblasts in which PKC was down‐regulated by prolonged (24 h) treatment with 300 nM PMA. These data indicate that treatment of fibroblasts with exogenous PLC results in PKC‐dependent activation of PLD.
Effect of clofibric acid on the turnover of the fatty acid‐binding protein identified in cultured endothelial cells from bovine aorta
Authors: Robers Markus , Loddenkötter Brigitte , Kresse Hans , Spener Friedrich 
Published: November 2006

AbstractSeveral types of fatty acid‐binding proteins are found in mammalian cells. Cultured endothelial cells from bovine aorta were shown to contain exclusively the cardiac‐type fatty acid‐binding protein (cFABP) with a mean concentration of 90 ng cFABP/mg extract protein. Only small variations were observed from passage to passage. In pulse‐chase labeling experiments with L‐[35S]methionine, a half‐life of 4.0 d was measured for cFABP which is about two times longer than the average half‐life of the extracted proteins. These data imply that in aortic endothelial cells cFABP is not subject to short‐term regulation. However, addition of clofibric acid to the culture medium led to a shortening of the half‐life of cFABP, which was compensated for by an increase in its biosynthesis. The turnover of the bulk of extract proteins remained unchanged when the cells were challenged with clofibric acid.
Structure‐function relationships of alkyl‐lysophospholipid analogs in selective antitumor activity
Authors: Vogler William R. , Olson Anita C. , Hajdu Joseph , Shoji Mamoru , Raynor Robert , Kuo J. F. 
Published: November 2006

AbstractThis investigation was initiated in order to delineate the structure‐function relationship of the anticancer alkyllysophospholipids and assess their degree of selective cytotoxicity toward neoplastic cells. A series of glycerol phosphocholine analogs with varying substitutions in thesn‐1 andsn‐2 position were tested for their inhibitory activity as measured by thymidine incorporation, clonogenic assays and effects on protein kinase C activity against a series of human leukemic cell lines and healthy bone marrow progenitor cells. The IC50 was determined for each of the compounds in each cell line and healthy bone marrow cells following a 4‐h incubation. The data indicated that a 16–18 carbon chain at thesn‐1 coupled with a short substitution atsn‐2 had the broadest antitumor activity and was the least toxic to normal bone marrow cells. The results provide a number of useful leads toward the design and development of potentially more active phospholipid compounds.
Interrelationship of stearic acid content and triacylglycerol composition of lard, beef tallow and cocoa butter in rats
Authors: Monsma Cathy C. , Ney Denise M. 
Published: November 2006

AbstractWe investigated modes whereby stearic acid (18∶0) exerts a neutral or cholesterol‐lowering effect using dietary fats which provided graded levels of 18∶0 and distinct triacylglycerol (TAG) profiles. Male Sprague‐Dawley rats (150–175 g) were fed diets containing 0.2% cholesterol and 16% fat from corn oil, or from 1% corn oil plus 15% lard (13.2% 18∶0), beef tallow (19.2% 18∶0) or cocoa butter (34.7% 18∶0) for 3 wk, and then killed in a fasted or fed state. Chylomicron (CM) fatty acid profiles suggested reduced absorption of 18∶0 with greater 18∶0 intake. CM TAG profiles indicated a reduction or loss of two TAG species compared to the TAG profiles of the stearate‐rich diets: 1‐palmitoyl‐2‐oleoyl‐3‐stearoyl glycerol (POS) and 1,3‐distearoyl‐2‐oleoyl glycerol (SOS). Hepatic total cholesterol concentrations were 54–77% lower (P<0.01) in the cocoa butter‐fed than the lard‐ and beef tallow‐fed groups. The cocoa butter group showed a significantly lower ratio of high‐density lipoprotein esterified/free cholesterol than all other groups. Hepatic stearoyl‐CoA and oleoyl‐CoA concentrations, the substrate and product for hepatic δ9 desaturase, were not significantly different for corn oil‐fed and cocoa butter‐fed groups in spite of a large difference in 18∶0 intake. These data suggest that the neutral or cholesterol‐lowering effect of 18∶0 is not due to hepatic conversion of stearic to oleic acid, and that POS and SOS are poorly absorbed from stearate‐rich dietary fats.
Radioprotection of mice by dietary squalene
Authors: Storm Heidi M. , Oh Suk Y. , Kimler Bruce F. , Norton Stata 
Published: November 2006

AbstractMale C3H mice were fed a diet containing 2% squalene for 14 d prior to and 30 d subsequent to exposure to 6, 7 or 8 Gy of whole body γ‐irradiation (Cesium‐137). After 14 d on squalene‐supplemented diet, plasma and jejunal tissue squalene levels were 2X and 15X that of controls. Seven days after irradiation, total white cell counts and total lymphocyte counts were substantially depressed in a radiation dose‐dependent manner. Although counts in the squalene group were consistently (18–119%) higher than those in the corresponding dietary control group, the differences between dietary groups at any single dose were not significant. Nuclear area of villus cells in the jejunum of both dietary groups was significantly reduced (20%) by day 11 post‐irradiation but the nuclear area in squalene‐fed mice was significantly greater (15%) than in controls, before and after irradiation. There were no differences in body weight as a function of either diet or radiation dose prior to the first observations of animal lethality. Animal survival was decreased from 100 to 0% at 30 d post‐irradiation by radiation doses of 6–8 Gy, with the greatest difference between dietary groups being observed at 7 Gy (median survival times of 12 and 16 d for control and squalene groups, respectively). Overall, survival of squalene‐fed mice was significantly prolonged compared with control‐fed mice (P=0.0054 by censored multiple regression analysis). It is concluded that squalene conferred some cellular and systemic radioprotection to mice receiving these lethal whole‐body radiation doses.