bluuebunny/crossref_metadata_2025_split huggingface dataset:
Incorporation of long‐chain n‐3 fatty acids in tissues and enhanced bone marrow cellularity with docosahexaenoic acid feeding in post‐weanling Fischer 344 rats
Authors: Atkinson Trevor G. , Barker Heather J. , Meckling‐Gill Kelly A. 
Published: November 2006

AbstractWe wanted to examine the effects of an oil rich in docosahexaenoic acid (DHA), without eicosapentaenoic acid, on the composition of membrane phospholipid in a variety of tissues. Our in vitro studies had previously shown that DHA could modify glucose and nucleoside transport in cells in culture and also increase selectivity of the nucleoside drug, arabinosylcytosine (araC) toward tumor cells. Here we wanted to examine what effect DHA supplementation would have in the whole animal in terms of the chemosensitivity of normal bone marrow, the dose‐limiting tissue during chemotherapy, to araC. The purpose was to determine whether fatty acid supplementation might be useful as an adjuvant to chemotherapy. We fed diets containing 5% (w/w) low fat‐corn oil (LF‐CO group), 10% moderate fat‐safflower oil (MF‐SO group), or 10% DHASCOTM (MF‐DHA group) to weanling Fischer 344 rats for 8–9 wk. Feed intake and growth were not different between the different diets. Similarly, treatment of animals with the chemotherapeutic drug araC did not differentially affect growth, feed intake, or tissue fatty acid composition for the different diet groups. Fatty acid compositions of bone marrow, liver, red blood cells, plasma phospholipid and triglyceride, as well as skeletal and cardiac muscle, were substantially different between the dietary groups. The DHASCOTM oil contained 46% DHA (22:6n‐3) and resulted in profound incorporation of DHA in all tissues examined. The most dramatic response was seen in skeletal muscle of MF‐DHA fed animals where DHA represented 46% of membrane phospholipid fatty acids. This is likely to have consequences to muscle function. Although DHASCOTM contains a similar level of saturated fatty acids (42%), few differences in saturates were noted between the various dietary groups for most of the tissues examined. Both LF‐CO and MF‐SO diets were hypercholesterolemic, and the LF‐CO was also hypertriglyceridemic compared to the chow‐fed animals. Animals fed the MF‐DHA diet had the lowest triglyceride levels of any of the treatment groups and cholesterol levels comparable to chow‐fed animals. MF‐DHA had substantially higher numbers of colony‐forming units‐granulocyte macrophage (CFU‐GM) as reflected in a twofold higher bone marrow cellularity than either chow or LF‐CO animals, suggesting expansion of the bone marrow compartment with DHA feeding. Although higher than LF‐SO, the number of CFU‐GM in MF‐SO animals was not significantly higher than animals fed chow. Bone marrow from LF‐CO animals appeared to be more resistant to araC treatment than either MF group. Thus, DHA, fed as DHASCOTM, has advantages over low or moderate n‐6 diets and chow as it is has both hypolipidemic‐ and bone marrow‐enhancing properties in weanling Fischer 344 rats. This suggests that DHA supplementation may be useful in adjuvant chemotherapy.
Non‐insulin dependent diabetes mellitus in Psammomys obesus is independent of changes in tissue fatty acid composition
Authors: Collier G. R. , Collier F. McL , Sanigorski A. , Walder K. , Cameron‐Smith D. , Sinclair A. J. 
Published: November 2006

AbstractRecently it has been postulated that membrane fatty acid composition may be involved in the pathogenesis of insulin resistance and non‐insulin dependent diabetes mellitus (NIDDM). The aim of this study was to determine whether alterations in tissue phospholipid (PL) fatty acids are present in hyperglycemic and hyperinsulinemic Psammomys obesus. On a native diet of salt bush, P. obesus (Israeli sand rat) remains lean and free of diabetes; however, when placed on a normal laboratory chow, a significant proportion of these animals develops a number of metabolic disorders associated with NIDDM, providing an ideal animal model of obesity and NIDDM. Four groups of mature P. obesus were studied: group A; normoglycemic and normoinsulinemic; group B: normoglycemic and hyperinsulinemic; group C: hyperglycemic and hyperinsulinemic; and group D: hyperglycemic hypoinsulinemic. In liver and red gastrocnemius muscle, there were no significant differences between groups, A, B, and in fatty acid composition of PL. Minor differences in individual fatty acids were demonstrated in group D animals (increased liver 20∶4n‐6 and increased muscle 22∶5n‐3); however, the unsaturation indices in liver and muscle were not significantly different between any of the groups. In considering that the minor changes in group D animals were not demonstrated in hyperinsulinemic group B animals or hyperglycemic, hyperinsulinemic group C animals, it is likely that the differences in group D animals were secondary to the more severe disturbances in glucose homeostasis and hypoinsulinemia present in these animals. The results of this study suggest that in this rodent diabetic model significant disturbances in glucose homeostasis and hyperinsulinemia may develop independently of changes in tissue fatty acid composition.
Phospholipid biosynthetic enzymes in human brain
Authors: Ross Brian M. , Moszczynska Anna , Blusztajn Jan K. , Sherwin Allan , Lozano Andres , Kish Stephen J. 
Published: November 2006

AbstractGrowing evidence suggests an involvement of brain membrane phospholipid metabolism in a variety of neurodegenerative and psychiatric conditions. This has prompted the use of drugs (e.g., CDPcholine) aimed at elevating the rate of neural membrane synthesis. However, no information is available regarding the human brain enzymes of phospholipid synthesis which these drugs affect. Thus, the objective of our study was to characterize the enzymes involved, in particular, whether differences existed in the relative affinity of substrates for the enzymes of phosphatidylethanolamine (PE) compared to those of phosphatidylcholine (PC) synthesis. The concentration of choline in rapidly frozen human brain biopsies ranged from 32–186 nmol/g tissue, a concentration similar to that determined previously for ethanolamine. Since human brain ethanolamine kinase possessed a much lower affinity for ethanolamine (Km=460 μM) than choline kinase did for choline (Km=17 μM), the activity of ethanolamine kinase in vivo may be more dependent on substrate availability than that of choline kinase. In addition, whereas ethanolamine kinase was inhibited by choline, and to a lesser extent by phosphocholine, choline kinase activity was unaffected by the presence of ethanolamine, or phosphoethanolamine, and only weakly inhibited by phosphocholine. Phosphoethanolamine cytidylyl‐transferase (PECT) and phosphocholine cytidylyltransferase (PCCT) also displayed dissimilar characteristics, with PECT and PCCT being located predominantly in the cytosolic and particulate fractions, respectively. Both PECT and PCCT exhibited a low affinity for CTP (Km approximately 1.2 mM), suggesting that the activities of these enzymes, and by implication, the rate of phospholipid synthesis, are highly dependent upon the cellular concentration of CTP. In conclusion, our data indicate different regulatory properties of PE and PC synthesis in human brain, and suggest that the rate of PE synthesis may be more dependent upon substrate (ethanolamine) availability than that of PC synthesis.
Isolation and characterization of inositol sphingophospholipids from Phytophthora parasitica Dastur
Authors: Bruneteau Maud , Fournol Florence , Gandon Corinne , Becchi Michel , Pivot Véronique 
Published: November 2006

AbstractSeveral inositol sphingophospholipids (ISPL) were isolated from mycelia of Phytophthora parasitica Dastur, a phytopathogenic fungus of carnation. The ISPL structures were determined by fast atom bombardment. All ISPL consisted of ceramides linked to inositol phosphate. We investigated the effect of growth conditions on the ISPL produced in four different media that are commonly used for fungal cultures. We showed that P. parasitica Dastur synthesized four major classes of compounds with molecular weights of Mr=751, 807, 835, and 849 containing the 16:1 base and the 16:0 or 20:0 or 22:0 or 22h:1 N‐acyl group. The relative abundance of the different ISPL is dependent on growth conditions.
Nuclear magnetic resonance characterization of 6α‐chloro‐5β‐cholestane‐3β,5‐diol formed from the reaction of hypochlorous acid with cholesterol
Authors: Carr Anitra C. , Winterbourn Christine C. , Blunt John W. , Phillips Andrew J. , Abell Andrew D. 
Published: November 2006

AbstractHyopochlorous acid generated by neutrophil myeloperoxidase has been shown to convert cholesterol into three different chlorohydrin isomers which previously had not been fully characterized. We have reacted hypochlorous acid with cholesterol/1,2‐dipalmitoyl phosphatidylcholine liposomes to give these three major products and established that they are 6β‐chloro‐5α‐cholestane‐3β,5‐diol (chlorohydrin 1), 5α‐chloro‐6β‐cholestane‐3β,6‐diol (chlorohydrin 2) and 6α‐chloro‐5β‐cholestane‐3β,5‐diol (chlorohydrin 3). These products were separated by thin‐layer chromatography and fully characterized by 1H, 13C, attached proton test, doublequantum correlation spectroscopy, total correlation spectroscopy, heteronuclear multiple bond correlation and heteronuclear multiple quantum coherence nuclear magnetic resonance spectroscopy.
Separation and quantitation of linoleic acid oxidation products in mammary gland tissue from mice fed low‐ and high‐fat diets
Authors: Johnson Jennifer A. , Blackburn Mary L. , Bull Arthur W. , Welsch Clifford W. , Throck Watson J. 
Published: November 2006

AbstractWe have developed an assay for the isolation and quantitation by gas chromatography‐mass spectrometry (GC‐MS) of free 9‐ and 13‐hydroxyoctadecadienoic acid (9‐HODE, 13‐HODE) in the mammary glands of female mice. Internal standards consisting of 18O2‐labeled analogs of 9‐ and 13‐HODE are added to pulverized frozen tissue prior to extraction with ethanol. Nonlipid materials are removed in a chloroform/methanol/water extraction step. The remaining lipid material is methylated with ethereal diazomethane, and much of the nonoxygenated fatty acid methyl esters are removed via silica solid‐phase extraction. Samples are either further derivatized with bis(trimethylsilyl)trifluoroacetamide to form the trimethylsilyl ethers for quantitative analysis by GC‐MS or are analyzed as the methyl esters by chiral high‐performance liquid chromatography to determine the enantiomeric distribution of the 9‐ and 13‐HODE. The extraction and quantitation protocol was applied to the analysis of mammary glands for free 9‐ and 13‐HODE from mice fed isocaloric diets containing 20% corn oil, 5% corn oil, or 20% beef tallow. Chiral analysis of the products showed higher production of 13(S)‐HODE relative to 13(R)‐HODE; the enantiomeric excess is most likely due to enzymatic production of 13‐HODE superimposed on a background of autoxidative production of 13(R)‐plus 9(S)‐ and 9(R)‐HODE. In addition, the effect of sample handling and storage conditions on the formation of 9‐ and 13‐HODE in the samples was assessed by exposing aliquots of a common pool of rat mammary gland tissue to specified conditions prior to analysis. This methodology will be important during investigations of the contribution of linoleate oxidation products to the enhancement of mammary tumorigenesis by dietary fat.
Effect of liposome‐encapsulated hemoglobin on triglyceride, total cholesterol, low‐density lipoprotein, and high‐density lipoprotein cholesterol measurements
Authors: Abdullah F. , Whiteford M. , Mathiak G. , Ovadia P. , Rudolph A. , Neville L. F. , Rabinovici R. 
Published: November 2006

AbstractThe present study investigated the effect of liposome‐encapsulated hemoglobin (LEH), an experimental oxygen‐carrying resuscitation fluid, on triglyceride, total cholesterol, and low density lipoprotein (LDL), and high density lipoprotein (HDL) cholesterol measurements. In vivo, the intravenous infusion of LEH (5.6 mL/kg, n=6) elevated serum triglycerides (+92% vs. baseline, P<.05), total cholesterol (+25% vs. baseline, P<.01), LDL cholesterol (+72% vs. baseline, P<.01) and had no effect on serum HDL cholesterol. In addition, LEH did not alter the elevation in serum triglycerides (+302% vs. baseline, P<.01) and LDL cholesterol (+86% vs. baseline, P<.01) induced by lipopolysaccharide (3.6 mg/kg, i.v., n=6). Ex vivo, measurements of triglycerides and total cholesterol as well as LDL and HDL cholesterol in whole blood from naive rats were not changed by the addition of LEH (0–50%, n=6). In vitro, the addition of a fixed concentration of LEH (50%, n=6) to varying concentrations of cholesterol solution (0–50%), or vice versa, had no effect on cholesterol determination. It is therefore concluded that LEH only minimally affects serum levels of triglycerides, total cholesterol, LDL cholesterol, and HDL cholesterol and does not interfere with their measurement.
The effect of dietary arachidonic acid on platelet function, platelet fatty acid composition, and blood coagulation in humans
Authors: Nelson G. J. , Schmidt P. C. , Bartolini G. , Kelley D. S. , Kyle David 
Published: November 2006

AbstractArachidonic acid (AA) is the precursor of thromboxane and prostacyclin, two of the most active compounds related to platelet function. The effect of dietary AA on platelet function in humans is not understood although a previous study suggested dietary AA might have adverse physiological consequences on platelet function. Here normal healthy male volunteers (n=10) were fed diets containing 1.7 g/d of AA for 50 d. The control diet contained 210 mg/d of AA. Platelet aggregation in the platelet‐rich plasma was determined using ADP, collagen, and AA. No statistical differences could be detected between the aggregation before and after consuming the high‐AA diet. The prothrombin time, partial thromboplastin time, and the antithrombin III levels in the subjects were determined also. There were no statistically significant differences in these three parameters when the values were compared before and after they consumed the high‐AA diet. The in vivo bleeding times also did not show a significant difference before and after the subjects consumed the high‐AA diet. Platelets exhibited only small changes in their AA content during the AA feeding period. The results from this study on blood clotting parameters and in vitro platelet aggregation suggest that adding 1.5 g/d of dietary AA for 50 d to a typical Western diet containing about 200 mg of AA produces no observable physiological changes in blood coagulation and thrombotic tendencies in healthy, adult males compared to the unsupplemented diet. Thus, moderate intakes of foods high in AA have few effects on blood coagulation, platelet function, or platelet fatty acid composition.
Increased dietary arachidonic acid enhances the synthesis of vasoactive eicosanoids in humans
Authors: Ferretti Aldo , Nelson Gary J. , Schmidt Perla C. , Kelley Darshan S. , Bartolini Giovanni , Flanagan Vincent P. 
Published: November 2006

AbstractData on the effect of dietary arachidonic acid (AA) (20∶4n‐6) on the synthesis of thromboxane and prostacyclin (PGI2) in humans are lacking. We measured the effect of 1.5 g/d (ca. 0.5 en%) of 20∶4n‐6 added isocalorically to a stabilization (low‐AA) diet on the excretion of 11‐dehydrothromboxane B2 (11‐DTXB2) and 2,3‐dinor‐6‐oxo‐PGF1α (PGI2‐M). In a crossover design, 10 healthy men, living in a metabolic unit, were fed a diet (low‐AA) containing 210 mg/d of 20∶4n‐6 for 65 d and an identical diet (high‐AA) that contained 1.5 g/d of additional 20∶4n‐6 for 50 d. Three‐day urine pools were collected at the end of each dietary period and analyzed for eicosanoids by gas chromatography‐electron capture negative ion‐tandem mass spectrometry. Mean excretion of 11‐dehydrothromboxane B2 was 515±76, 493±154, and 696±144 ng/d (SD; n=10) during the acclimation (15 d) low‐AA diet and high‐AA diet periods, respectively (41% increase from low‐AA to high‐AA diet, P=0.0037); mean excretion of PGI2‐M was 125±40, 151±36, and 192±55 ng/d (SD; n=10) during acclimation (15 d) low‐AA and high‐AA diets, respectively (27% increase from low‐AA to high‐AA diets; P=0.0143). Thus, both the metabolites of thromboxane and PGI2 increase on the high‐AA diet. Furthermore, both indicated changes in metabolite excretion may be associated with measurable effects on several physiologically significant cellular functions, such as platelet aggregation in vivo and inflammation in response to immune challenges.
Influence of dietary arachidonic acid on metabolism in vivo of 8 cis, 11 cis, 14‐eicosatrienoic acid in humans
Authors: Emken E. A. , Adlof R. O. , Duval S. M. , Nelson G. J. 
Published: November 2006

AbstractThis study investigated the influence of dietary arachidonic acid (20∶4n‐6) on Δ5 desaturation and incorporation of deuterium‐labeled 8cis, 11cis, 14‐eicosatrienoic acid (20∶3n‐6) into human plasma lipids. Adult male subjects (n=4) were fed diets containing either 1.7 g/d (H120∶4 diet) or 0.21 g/d (LO20∶4 diet) of arachidonic acid for 50 d and then dosed with a mixture containing ethyl esters of 20∶3n‐6[d4] and 18∶1n‐9[d2]. A series of blood samples was sequentially drawn over a 72‐h period, and methyl esters of plasma total lipid, triacylglycerol, phospholipids, and cholesteryl ester were analyzed by gas chromatography‐mass spectrometry. Based on the concentration of 20∶3n‐6[d4] in total plasma lipid, the estimated conversion of 20∶3n‐6[d4] to 20∶4n‐6[d4] was 17.7.±0.79% (HI20∶4 diet) and 2.13±1.44% (LO20∶4 diet). The concentrations of 20∶4n‐6[d4] in total plasma lipids from subjects fed the HI20∶4 and LO20∶4 diets were 2.10±0.6 and 0.29±0.2 μmole/mL plasma/mmole of 20∶3n‐6[d4] fed/kg of body weight. These data indicate that conversion of 20∶3n‐6[d4] to 20∶4n‐6[d4] was stimulated 7‐8‐fold by the HI20∶4 diet. Phospholipid acyltransferase was 2.5‐fold more selective for 20∶3n‐6[d4] than 18∶1n‐9[d2], and lecithin:cholesterol acyltransferase was 2‐fold more selective for 18∶1n‐9[d2] than 20∶3n‐6[d4]. These differences in selectivity were not significantly influenced by diet. Absorption of ethyl 20∶3n‐6[d4] was about 33% less than ethyl 18∶1n‐9[d2]. The sum of the n‐6 retroconversion products from 20∶3n‐6[d4] in total plasma lipids was about 2% of the total deuterated fatty acids. Neither absorption nor retroconversion appears to be influenced by diet.
Metal ion stimulation of phospholipase D‐like activity of isolated rat intestinal mitochondria
Authors: Madesh M. , Balasubramanian K. A. 
Published: November 2006

AbstractPresence of phospholipase D‐like (PLD) activity in the intestinal mitochondria was identified using endogenous phospholipids as substrate. The enzyme had a pH optimum of 6.5, did not show trans‐phosphatidylation activity in the presence of ethanol or butanol, and the product formed was phosphatidic acid (PA). This was confirmed by separation of reaction products by high‐performance liquid chromatography and analysis of composition of the PA formed which gave phosphate/fatty acid ratio of 1∶2. PLD‐like activity was further confirmed by the formation of ethanolamine and choline as products of enzyme action. This activity was stimulated by various metal ions; when stimulated by Mg2+ and Ba2+, it hydrolyzed both phosphatidylcholine and phosphatidylethanolamine, and when stimulated by Ca2+, it preferentially hydrolyzed phosphatidylethanolamine. There was no requirement for sodium oleate for the PLD‐like activity in mitochondria. These results suggest that intestinal mitochondria have an active PLD‐like enzyme which differs in certain properties from phospholipase D from other tissues.
Membrane lipid metabolism and phospholipase activity in insect Spodoptera frugiperda 9 ovarian cells
Authors: Yeh Li‐Hong P. , Bajpai Rakesh K. , Sun Grace Y. 
Published: November 2006

AbstractAlthough there is increasing use of insect ovarian Sf9 cells for the production of recombinant proteins, namely, via the baculovirus vector expression system, little is known about the lipids in the cell membrane and whether endogenous phospholipases are present for regulation of the cell membrane lipids. In this study, analysis of membrane lipids of Sf9 cells indicated the presence of phosphatidylethanolamine (PE) (diacyltype) and phosphatidylcholine as major phospholipids, followed by phosphatidylserine and phosphatidylinositol (PI), and only trace amounts of ethanolamine plasmalogen. These phospholipids contain high proportions of monoenoic fatty acids, e.g., 16∶1 and 18∶1, which comprise more than 70% of the total fatty acids although small amounts of polyunsaturated fatty acids such as 18∶2 and 20∶4 are also present. When Sf9 cells were incubated in a culture medium containing [14C]oleic acid and [14C]arachidonic acid, a large portion of the labels were incorporated into membrane phospholipids. Using [14C]arachidonoyl‐phospholipids as substrates for incubation with cell homogenate and subcellular fractions, results indicate the presence of a Ca2+‐independent phospholipase A (PLA2) in the Sf9 cell cytosol fraction. This PLA2 shows a high preference for hydrolysis of PE and is active at a pH range of 7–9. Unlike the brain cells which contain active phospholipase C (PLC) specific for phosphatidylinositol, only limited amount of diacylglycerol (DAG) was released from [14C]arachidonoyl‐PE in the Sf9 cells. Taken together, this study demonstrates active metabolism of membrane phospholipids in Sf9 cells, most likely mediated by acyltransferases and PLA2. Furthermore, despite the absence of PLC for PI, limited amount of DAG could be generated through hydrolysis of PE.
Effect of docosahexaenoic acid on mouse mitochondrial membrane properties
Authors: Stillwell William , Jenski Laura J. , Thomas Crump F. , Ehringer William 
Published: November 2006

AbstractLong‐chain polyunsaturated (n‐3) fatty acids have been proposed to be involved in a wide variety of biological activities. In this study, mitochondrial docosahexaenoic acid (DHA) levels were increased by either dietary manipulation or by fusing the mitochondria with phospholipid vesicles made from 1‐stearoyl‐2‐docosahexaenoyl‐sn‐glycero‐3‐phosphocholine (18:0/22:6 PC). The fused mitochondria exhibited a DHA‐induced decrease in respiratory control index (RCI) and membrane potential and an increase in proton movement. The modified mitochondria also demonstrated an increase in fluidity (as detected by 1,6‐diphenyl‐1,3,5‐hexatriene anisotropy) and changes in membrane structure detected by the fluorescence probes MC540 and pyrene decanoate. Proton movement in lipid vesicles made from mitochondrial lipid extracts was shown to be enhanced by incorporated 18:0/22:6 PC. Mitochondria were isolated from young (5‐mon) and old (24‐mon) mice which were maintained on either a diet rich in saturated fats (hydrogenated coconut oil) or rich in n−3 polyunsaturated fats (menhaden oil). Mitochondrial bioenergetic function was followed by RCI, state 3 respiration, ATP level, and phosphate uptake. In addition, lipid composition, phospholipid area/molecule, and extent of lipid peroxidation were also determined. Decreases in RCI for the menhaden oil diet‐modified mitochondria paralleled those in which DHA levels were enhanced by fusion with phospholipid vesicles. RCI reductions are attributed to DHA‐induced increases in H+ movement, producing diminished mitochondrial membrane potentials. One purpose of this project was to determine if the deleterious effects of aging on mitochondrial bioenergetic function could be reversed by addition of n−3 fatty acids. The experiments reported here indicate that incorporation of long‐chain polyunsaturated n−3 fatty acids into mitochondrial membranes does not appear likely to reverse the effects of age on mitochondrial function.