bluuebunny/crossref_metadata_2025_split huggingface dataset:
Membrane lipid alteration: Effect on cellular uptake of mitoxantrone
Authors: Burns C. Patrick , Haugstad Bradley N. , Mossman Craig J. , North James A. , Ingraham Leah M. 
Published: November 2006

AbstractWe have studied the effect of membrane structural alteration on the cellular association of the anticancer drug mitoxantrone whose uptake is not carrier‐mediated. Membrane fatty acids of L1210 cells were modified by incubating the cells with the highly unsaturated docosahexaenoic acid (22∶6), which results in isolated plasma membranes with 37% of the fatty acids as 22∶6, or with the monounsaturated oleic acid (18∶1), which results in 58% of the fatty acids as 18∶1. The rate of uptake by 22∶6‐enriched cells during the first min was 62% greater than by those enriched with 18∶1. The higher rate was recorded at 0.5–16 μM, pH 6.6–7.6 and temperatures 10–40 C. The difference in cell‐associated drug apparently was not due simply to a change in mitoxantrone solubility as measured by partitioning of the drug in lipophilic‐hydrophilic systems containing lipids from the fatty‐acid altered cells. We conclude that the type of fatty acids contained in L1210 cell membranes can affect the cell association of mitoxantrone. This effect could be on transmembrane flux or be due to differences in binding of the drug to intracellular structures.
Hydroxyacid derivatives in human epidermis
Authors: Wertz Philip W. , Downing Donald T. 
Published: November 2006

AbstractThe principal objective of this investigation was to examine the ω‐hydroxyacid derivatives in the cornified layer of human skin. Toward this end, sunburn peelings were collected, and the lipids were extracted with chlofoform/methanol. Comparison with authentic standards by thin layer chromatography (TLC) indicated the presence of both N‐(ω‐acyloxy)acylsphingosine (acylceramide) and ω‐acyloxy fatty acid (acyl acid), which accounted for 1.7% and 2.0% of the total lipid, respectively, as estimated by photodensitometry of the charred chromatograms. Each of these lipids was isolated by preparative TLC, hydrolyzed, and the resulting fragments were further analyzed by TLC and by gas liquid chromatography (GLC) of appropriate derivatives. In both of these lipids, the predominant ω‐hydroxyacid proved to be the 30‐carbon saturated species (56–59% of the total), while linoleate was the major ester‐linked fatty acid. Linoleate was more abundant in the acyl acid (38.0%) than in acylceramide (21.4%). These findings represent the first demonstration of acyl acid in human skin and support the proposition that acyl acid, like the other linoleate‐rich ω‐hydroxyacid derivatives, functions as a molecular rivet in maintaining epidermal structure and fucntion.
Trifluoperazine increases fatty acid turnover in phospholipids in cultured human fibroblasts
Authors: Mazière Cecile , Mazière Jean‐Claude , Mora Liliana , Auclair Martine , Polonovski Jacques 
Published: November 2006

AbstractA 24‐hr pretreatment of cultured human fibroblasts with trifluoperazine induced a marked increase in incorporation of saturated (stearic, palmitic) and unsaturated (oleic, arachidonic) fatty acids into phospholipids (1.5‐ to 2‐fold for 5.10−5 M trifluoperazine). Concomitantly, incorporation into cholesteryl esters was strongly inhibited (20% of control for 5.10−5 M trifluoperazine). The drug did not change the phospholipid composition of treated cells. The effect of trifluoperazine on oleic acid incorporation into phospholipids was time‐dependent and reached a maximum after a six‐hr preincubation with the drug. Trifluoperazine also induced an increase in the rate of chase of oleic acid from the different phospholipid classes. In vitro preincubation of cell‐free extracts with trifluoperazine resulted in activation of phospholipid acyltransferases, whereas cholesterol acyltransferase activity was decreased. The rapid effect of trifluoperazine together with its effect on a cell‐free system suggests a direct action of this amphiphilic drug on the acyltransferase activities, probably by modification of the structural organization of cellular membranes.
Disposition and metabolism of pristane in rat
Authors: Le Bon A. M. , Cravedi J. P. , Tulliez J. E. 
Published: November 2006

AbstractThe fate of pristane (2,6,10,14‐tetramethylpentadecane), a widespread isoprenoid hydrocarbon, has been studied in rats after a single per os administration of3H‐labeled pristane. The balance study showed an extensive fecal excretion (66%) mainly as unchanged hydrocarbon, whereas about 14% of ingested pristane was excreted in urine as pristane metabolites and tritiated water. After one wk, 8.3% of the ingested3H still was stored in the carcass, and radioactive distribution in tissues and organs showed a preferential incorporation into adipose tissue and liver. Over 75% of the radioactivity stored in the carcass was associated with pristane metabolites and tritiated water. Tissue metabolites were characterized by thin layer chromatography, gas chromatography and mass spectrometric analyses. Four metabolites were identified: pristan‐1‐ol, pristane‐2‐ol, pristanic acid and 4,8,12‐trimethyltridecanoic acid. These demonstrate that this isoprenoid hydrocarbon undergoes subterminal hydroxylation or terminal oxidation followed by the classical β‐oxidation process. Incorporation of metabolites in phospholipids and more particularly in the phosphatidylserine fraction has been observed and is discussed.
Oxidation of 1‐O‐(alk‐1‐enyl)‐2,3‐di‐O‐acylglycerols: Models for plasmalogen oxidation
Authors: Foglia Thomas A. , Nungesser Edwin , Marmer William N. 
Published: November 2006

AbstractAlk‐1‐enyl diacyl glycerides, model compounds for plasmalogen lipids, were synthesized for use as substrates in oxidation studies. The neutral plasmalogen glycerides prepared included 1‐O‐(hexadec‐1‐enyl)‐2,3‐di‐O‐stearoylglycerol (4a) and 1‐O‐(hexadec‐1‐enyl)‐2‐O‐linoleoyl‐3‐O‐stearoylglycerol (4b). Oxidative disappearance of these glycerides was followed directly by high performance liquid chromatography (HPLC). The extent of oxidation of the side chains of these glycerides, i.e. the alkenyl ether and fatty acyl functions, was monitored by conversion of the side chains to dimethylacetal and methyl ester by methanolysis, followed by subsequent gas chromatography (GC) of the methanolysis products. Both analytical approaches show that the alkenyl ether function of neat4a oxidizes more slowly than neat ethyl linoleate. However, the rate of alkenyl ether loss from4a is accelerated in the presence of added ethyl linoleate. Moreover, when the linoleoyl group is incorporated into the 2‐position of the alkenyl glyceride, as in4b, the rate of loss of the alkenyl group was shown to be similar to the rate of loss of the linoleoyl group. These results suggest that oxidation of plasmalogen glycerides should not be ignored as a factor that contributes to the oxidative instability of animal tissue.
Nanogram quantification of nonpolar lipid classes in environmental samples by high performance thin layer chromatography
Authors: Conte Maureen H. , Bishop James K. B. 
Published: November 2006

AbstractA sensitive, simple, and rapid high performance thin layer chromatography (HPTLC) method that quantifies nanogram amounts of complex nonpolar lipid classes in environmental samples with a minimum of sample preparation is presented. The derivatization method is lipid‐specific and insensitive to carbon number or the degree of unsaturation of the fatty acids composing the lipid class compounds. Nonpolar lipid classes ranging from 10 to over 500 ng easily may be quantified in the same sample run. The coefficient of variation for sample replicates on different plates ranged from 2.3% to 5.9%. Accuracy of the method is better than 15%. The nonpolar lipid class composition of <53 μm oceanic particles in a vertical depth profile of the upper 600 meters of the Slope Water was determined to illustrate the HPTLC method. The observed changes in particulate lipid class composition indicate that secondary production by deep‐living organisms significantly alters suspended particle composition with depth in the water column.
The existence of a soluble plasmalogenase in guinea pig tissues
Authors: McMaster Christopher R. , Lu Can‐Qun , Choy Patrick C. 
Published: November 2006

AbstractThe distribution of plasmalogenase for the hydrolysis of 1‐alkenyl‐2‐acyl‐sn‐glycero‐3‐phosphoethanolamine (plasmenylethanolamine) in the subcellular fractions of guinea pig tissues was examined. Plasmalogenase activity was found in high abundance in the cytosolic fractions of the brain and the heart. Assessment of microsomal marker enzyme activities in the cytosolic fraction revealed that plasmalogenase activity in the cytosol was not due to microsomal contaminations. The characteristics of the cytosolic plasmalogenase were very similar to the microsomal enzyme with respect to the pH profile of the reaction, the presence of divalent cations and Km values for plasmenylethanolamine. However, the cytosolic enzyme was slightly less stable at 55°C than the microsomal enzyme. Cytosolic enzyme activity was eluted as a broad peak in Sepharose 6B chromatography with an average molecular weight of 250,000. Our results demonstrate that most of brain plasmalogenase activity is soluble which makes the brain cytosol an excellent source to initiate the purification of this enzyme.
Kinetics of photoperoxidation of arachidonic acid: Molecular mechanisms and effects of antioxidants
Authors: Iliou Jean‐Pierre , Jourd'heuil David , Robin Frédéric , Serkiz Bernard , Guivarc'h Pascale , Volland Jean‐Paul , Vilaine Jean‐Paul 
Published: November 2006

AbstractThe kinetics of photoperoxidation of [1−14C]arachidonic acid (20∶4n−6) at 1.32 mM was studied either with the unsaturated fatty acid alone or in the presence of 10μM of antioxidants and/or inhibitors of eicosanoid metabolism. The photosensitizer used wasmeso‐tetraphenylporphine. The time‐course of the reactions was followed by ultraviolet spectral analysis, thiobarbituric acid reactivity and high‐performance liquid chromatographic analysis of aliquots sampled every 15 min during the 4 h of irradiation. The kinetics of photoperoxidation of 20∶4n−6 can be divided into three main successive steps: (i) monohydroperoxidation, characterized by the appearance of conjugated diene patterns and monohydroperoxidized 20∶4n−6; (ii) secondary oxidation characterized by polyoxygenated products such as dihydroperoxidized 20∶4n−6 possessing conjugated triene patterns; and (iii) the disappearance of conjugated patterns and the oxidative cleavage of the products of the two first steps into aldehydic molecules reacting with thiobarbituric acid. During the first 90 min of irradiation, the mechanism of monohydroperoxidation (step one) is purely or predominantly type II photoperoxidation involving only singlet oxygen. This step was inhibited by β‐carotene and by BW755C (3‐amino‐1‐[3‐trifluoromethylphenyl]2‐pyrazoline). In contrast, the reactions involved in the second and third steps were predominantly type I photoperoxidation involving radical mechanisms. These latter steps were inhibited by β‐carotene, BW755C, vitamin E and probucol. Indomethacin and 5,8,11,14‐eicosatetraynoic acid did not alter 20∶4n−6 photoperoxidation. Thisin vitro model of lipid photoperoxidation allows the screening of antioxidants in accordance with their singlet oxygen quenching and/or free radical scavenging properties.
Increased globotriaosylceramide in familial dysautonomia
Authors: Strasberg Paula , Yeger Herman , Warren Irene 
Published: November 2006

AbstractFamilial Dysautonomia (FD) is an autosomal recessive disease of unknown etiology, occurring primarily in Ashkenazi Jews. Patients are neurologically impaired, with deficits primarily in autonomic and sensory functions. The biochemical and genetic defects have remained elusive, precluding carrier detection and prenatal diagnosis. High‐performance liquid chromatography data indicated up to a threefold increase in the neutral glycosphingolipid globotriaosylceramide in Dysautonomic fibroblasts and lymphoblasts. Total ganglioside values, measured by colorimetric, fluorometric or specific sodium borohydride incorporation, were decreased. Affected fibroblasts exhibited a range of pleomorphic phenotypes, such that the usual swirl‐like confluent growth pattern of normal fibroblasts was distorted to varying degrees, suggesting abnormalities in the FD plasma membrane, possibly affecting cell‐cell contacts. The glycosphingolipid increase could not be accounted for on the basis of markedly decreased α‐galactosidase activity, as in Fabry's disease, where patients also display decreased autonomic function.
Prolonged retention of doubly labeled phosphatidylcholine in human plasma and erythrocytes after oral administration
Authors: Galli Claudio , Sirtori Cesare R. , Mosconi Cristina , Medini Lucia , Gianfranceschi Gemma , Vaccarino Viola , Scolastico Carlo 
Published: November 2006

AbstractThe plasma kinetics of a preparation of dilinoleoyl phosphatidylcholine (DLPC) specifically labeled with3H in the choline moiety and with14C in the 2‐fatty acid (FA) were evaluated in six healthy volunteers after oral administration. Retention of both isotopes in plasma exceeded expectations, with a half‐life in the elimination phase of 172.2 h for3H and 69.7 h for14C. Up to 60 d after administration, there were still significant levels of radioactivity present in plasma. The relative stability of the [14C]FA label was demonstrated by the retention for more than 12 h of an isotope ratio close to that of the compound administered. The14C label of DLPC remained in position‐2, as assessed by cleavage of plasma phospholipids with phospholipase A2. The [3H]choline label showed an early incorporation into high density lipoproteins and subsequently into low density lipoproteins (LDL); conversely, the14C radioactivity was rapidly incorporated into triacylglycerols that were mainly associated with very low density lipoproteins. Radioactivity measurements revealed that both isotopes remained the longest time in LDL. In red blood cell (RBC) lipids, [3H]choline radioactivity accumulated over time, with a plateau after 48 h, whereas FA radioactivity accumulated more rapidly and was followed by a progressive decay. Analysis of the isotope ratio in these cells suggested an early incorporation of lyso products followed by rapid transfer of FA from plasma. The RBC maintained considerable radioactivity for a prolonged time, thus acting as a possible reservoir for the DLPC administered. Our study showed that dilinoleoyl PC remained in plasma longer than predicted based on earlier studies, and that after absorption the FA label was found in position 2.
Nonessential fatty acids in formula fat blends influence essential fatty acid metabolism and composition in plasma and organ lipid classes in piglets
Authors: Wall Katharine M. , Diersen‐Schade Deborah , Innis Sheila M. 
Published: November 2006

AbstractThe n‐6 and n‐3 fatty acid status of developing organs is the cumulative result of the diet lipid composition and many complex events of lipid metabolism. Little information is available, however, on the potential effects of the saturated fatty acid chain length (8:0–16:0) or oleic acid (18:1) content of the diet on the subsequent metabolism of the essential fatty acids 18:2n‐6 and 18:3n‐3 and their elongated/desaturated products. The effects of feeding piglets formulas with fat blends containing either coconut oil (12:0±14:0) or medium chain triglycerides (MCT, 8:0±10:0) but similar levels of 18:1, 18:2n‐6 and 18:3n‐3, or MCT with high or low 18:1 but constant 18:2n‐6 and 18:3n‐3 on the fatty acid composition of plasma, liver and kidney triglycerides, phospholipids and cholesteryl esters, and of brain total lipid, were studied. Diet‐induced changes in the fatty acid composition of lipid classes were generally similar for plasma, liver and kidney. Dietary 18:1 content was reflected in tissue lipids and was inversely associated with levels of 18:2n‐6. Lower percentage of 18:2n‐6, however, was not associated with lower levels of its elongated/desaturated product 20:4n‐6 but was associated with higher levels of 22:6n‐3. Feeding coconut oilvs. MCT resulted in lower 18:1 levels in all lipids, and higher percentages of 20:4n‐6 in tissue phospholipid. Increasing the dietary n‐6/n‐3 ratio from 5 to 8 significantly increased tissue percentage of 18:2n‐6 and decreased phospholipid 22:6n‐3. In contrast to plasma, liver and kidney, brain lipid fatty acid composition was not influenced by the formula saturated fatty acid chain length, content of 18:1, or n‐6/n‐3 ratio. In summary, the studies show that the dietary requirement for n‐6 and n‐3 fatty acids may be influenced by the nonessential saturated and monounsaturated fatty acids fed concurrently.
Formation of a thiamine disulfide complex with fatty acid: Mechanism of formation of the complex
Authors: Komata Yasuko , Fujie Tadao , Kaneko Akiko , Ueda Fumio , Urano Shiro 
Published: November 2006

AbstractThe formation of complexes between thiamine disulfide (TDS) orO‐acetyl thiamine disulfide (O‐acetyl TDS) and fatty acid or fatty acid methyl ester in methanol has been studied by fluorescence quenching and13C NMR relaxation (T1) measurements. The association constants (K‐values) of TDS andO‐acetyl TDS with fatty acids (from 11∶0 to 18∶0, and 18∶1, 18∶2, 18∶3 and 20∶4) and fatty acid methyl esters have been determined. These values do not depend on either the number of carbon atoms or the degree of unsaturation of the fatty acid. The K‐values of TDS andO‐acetyl TDS with fatty acid were 7.8 M−1 and 5.1 M−1, respectively. The K‐values of TDS andO‐acetyl TDS with fatty acid methyl ester were very small. These results show that the‐OH moiety in TDS and the‐COOH moiety in the fatty acid are necessary for formation of the complex
Purification and characterization of fatty acid‐binding protein from human placenta
Authors: Das Tanya , Sa Gourisankar , Mukherjea Manju 
Published: November 2006

AbstractPurification of a cytosolic fatty acid‐binding protein (FABP) from developing human placenta has been achieved, and its role in modulating the inhibition of human placental glucose‐6‐phosphate dehydrogenase (G6PD) by palmitoyl‐CoA (PAL‐CoA) has been studied. FABP was resolved into three peaks, viz. DE‐I, DE‐II and DE‐III, by DEAE cellulose chromatography. DE‐I was almost lipid‐free. Presence of endogenous fatty acids in DE‐II and DE‐III was detected by thin layer chromatography (TLC). Fatty acids were the only detectable lipid component in these fractions. Gas liquid chromatography (GLC) analysis revealed that DE‐II binds long chain saturated and unsaturated fatty acids nonspecifically, whereas DE‐III is mainly an arachidonic acid carrier. Each of these fractions, viz. DE‐I, DE‐II and DE‐III, has a molecular weight of 14,200 Daltons. Ouchterlony double immunodiffusion studies have confirmed the immunochemical identity of these three fractions of placental FABP. Separation in ion exchanger may be due to their different isoelectric points and varied types of binding affinities. Human placental G6PD was inhibited 50% by 0.03 mM PAL‐CoA. The DE‐II fraction of FABP enhanced the activity of G6PD in the absence of added PAL‐CoA and protected against PAL‐CoA inhibition of the enzyme. Such a modulating effect of FABP in this inhibition is attributable to binding of long chain acyl‐CoA rather than to a direct effect of FABP on the enzyme itself.
Isolation and chemical composition of surface‐active material from human lung lavage
Authors: Sadana T. , Dhall K. , Sanyal S. N. , Wali A. , Minocha R. , Majumdar S. 
Published: November 2006

AbstractSurface‐active material (SF) was isolated from human lung lavage fluid collected at autopsy employing differential and sucrose density gradient centrifugation. The isolated material showed well‐defined electron microscopic structure, consisting of clearly preserved, closely packed vesicles with limiting membranes and inclusion bodies. It showed a very high degree of alkaline phosphatase specific activity and was devoid of other subcellular contaminants. The isolated material also showed a high phospholipid/protein ratio and increasing surface activity when monitored at different stages of purification. It contained 68.5% phosphatidylcholine, 11.5% phosphatidylglycerol and relatively smaller amounts of phosphatidylethanolamine and other individual phospholipid (PL) classes. In addition, cholesterol, unesterified fatty acids, triacylglycerols and other neutral lipids were found. Saturated fatty acids, particularly palmitic acid (16∶0), predominated in the major PL fractions. However, various fatty acids of which oleic acid (18∶1) constituted a large proportion also are present. Chemical analysis of the material showed that besides lipids and proteins, nucleic acids, sialic acid, hexose, amino sugars, nitrogen and phosphorus were present. The delipidated material showed the presence of three to four proteins as characterized by sodium dodecylsulfate (SDS)‐polyacrylamide gel electrophoresis, and gel permeation chromatography on Sephadex G‐200 resolved two well‐separated peaks. The first fraction contained serum‐associated 68 kDa protein, while the second fraction had two apoproteins with molecular weights of 34 kDa and 10 kDa. These two proteins were associated with the SF and they, as well as the whole surface‐active material, strongly reacted with the antibody directed against the whole SF in a double‐diffusion immunoprecipitation assay. The first Sephadex fraction containing a 68 kDa protein did not produce any precipitation line when reacted against antisera.
Promotion of iron‐induced rat liver microsomal lipid peroxidation by copper
Authors: Beckman Jeffrey K. , Borowitz Stephen M. , Greene Harry L. , Burr Ian M. 
Published: November 2006

AbstractAlthough copper has been demonstrated to promote lipid peroxidation in a number of systems, the mechanisms involved have not been fully defined. In this study, the role of copper in modifying lipid peroxidation has been explored in rat hepatic microsomes. In an in vitro system containing reduced glutathione (GSH, 200 μM) and Tris buffer, pH 7,4, cupric sulfate (1–50 μM) potentiated lipid peroxidation induced by ferrous sulfate (10 μM) but was unable to elicit peroxidation in the absence of iron. Higher levels of cupric sulfate (100 μM or greater) were inhibitory. The nature as well as the extent of the peroxidative response of microsomes to cupric sulfate were dependent on glutathione levels in addition to those of iron. Cupric sulfate (100 μM) strongly potentiated ferrous ion‐induced lipid peroxidation in the presence of 400–800 μM GSH, while it inhibited peroxidation at lower levels of GSH (0–200 μM) and did not affect ferrous ion‐induced peroxidation with glutathione levels of 3–10 mM.The potentiating effect of copper on ferrous ion‐induced lipid peroxidation was further explored by investigating: (1) potential GSH‐mediated reduction of cupric ions; (2) potential copper/GSH‐mediated reduction of ferric ions (formed by oxidation during incubation); and (3) possible promotion of propagation reactions by copper/GSH. Our results indicate that cupric ions are reduced by GSH and thus are converted from an inhibitor to an enhancer of iron‐induced lipid peroxidation. Cuprous ions appear to potentiate lipid peroxidation by reduction of ferric ions, rather than by promoting propagation reactions. Iron (in a specific Fe+2/Fe+3 ratio) is then an effective promoter of initiation reactions.