bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of a single ingestion of sodium taurocholate on esterified cholesterol concentration in liver and cholesterol turnover in the rat
Authors: Mathé D. , Chevallier F. 
Published: November 2006

AbstractThe overall response of the rat's cholesterol metabolism to a single ingestion of taurocholate (80 mg) was studied with the isotopic equilibrium method. The bile acid production, measured by the daily14CO2 output of rats in isotopic equilibrium of [26‐14C]‐cholesterol, initially decreased and then increased. Conversely, the hepatic concentration of esterified cholesterol first increased and then decreased. Moreover, the ingestion of taurocholate increasing the intestinal absorption coefficient of dietary cholesterol increased the abosprtion and decreased the fecal excretion and the intestinal biosynthesis of cholesterol. The balance of these last effects is an excess cholesterol inflow. The classical hypothesis of negative feedback regulation of bile acid production fails to explain the observed biphasic effect of taurocholate. This compound, when its origin is exogenous, appears to stimulate the storage of esterified cholesterol in the liver, at the expense of bile acid synthesis. This accumulation rate takes into account not only the decrease in cholesterol transformation into bile acids but also the excess inflow of cholesterol. As the exogenous taurocholate was eliminated from the body, cholesteryl ester hydrolysis occurred and provided a supplementary source of free cholesterol for bile acid synthesis.
Effect of tibric acid on hepatic cholesterol synthesis in rats
Authors: Cayen M. N. , Dubuc J. , Dvornik D. 
Published: November 2006

AbstractMale albino rats were administered various oral doses of tibric acid daily for 1 week. Serum cholesterol and triglyceride levels were reduced, but total liver content of cholesterol, phospholipids, and triglycerides was increased. Tibric acid treatment suppressed the incorporation of both [14C] acetate and [3H] mevalonate into cholesterol by liver homogenates.
Fatty acids in femaleMacracanthorhynchus hirudinaceus (Acanthocephala)
Authors: Smith Wayne , Dunagan T. T. , Miller Donald M. 
Published: November 2006

AbstractNeutral lipids and phospholipids in the body wall, lemnisci and pseudocoel and neutral lipids of fluid found in the “tube” system of the lemnisci and the lacunar system of the body wall ofMacracanthorhynchus hirudinaceus (Acanthocephala) were determined by the technique of thin layer chromtography and gas chromatography (GC). Sixteen different fatty acids from nonpolar lipids were identified as follows: 8∶0, 10∶0, 11∶0, 12∶0, 13∶0, 14∶0, 14∶1, 16∶0, 18∶0, 18∶1, 18∶2 and/or 20∶0, 18∶3 and/or 20∶1, 20∶3, 22∶1, 24∶1 and 22∶6. In addition, there were three unidentified GC peaks corresponding to chain lengths greater than 20 carbons. Sixteen different fatty acids from phospholipids were identified in each of the three fractions analyzed. They were as follows: 10∶0, 11∶0, 12∶0, 13∶0, 14∶0, 14∶1, 16∶0, 16∶1, 18∶0, 18∶1, 18∶2 and/or 20∶0, 20∶2, 20∶3, 22∶1, 24∶1, and 22∶6. Four unidentified peaks were also observed. There was a significant difference in the percentage of lipid as well as the concentration of particular fatty acids when each fraction was compared. There was also an abundant supply of sterols and glycerides in each fraction.
In vitro conversion of erucic acid by microsomes and mitochondria from liver, kidneys and heart of rats
Authors: Clouet Pierre , Bezard Jean 
Published: November 2006

AbstractMicrosomes and mitochondria of liver, kidneys, and heart were incubated with [14‐14C]erucic acid in three assay media: one favorable for chain elongation (NADPH+KCN), another favorable for β‐oxidation and the last one for shortening (NADP+KCN). Elongating reactions occurred mainly in microsomes, those of kidneys being very active; the mitochondria also showed some activity, heart mitochondria being, however, more active than the microsomes, when considering the amount of erucic acid activated. In the medium for β‐oxidation, practically no shortened fatty acids were found. On the contrary, when β‐oxidation was inhibited, and in the presence of NADP, the formation of shorter monoenes, probably in the outer membrane of the mitochondria, was observed, namely eicosenoic acid in high amount, oleic acid and hexadecenoic acid. Mitochondria from liver were very active as were those of heart, when compared with the quantity of activated erucic acid. In heart, the mitochondria shortened erucic acid into oleic acid and hexadecenoic acid, which were then probably used as energy substrates. With carnitine and without NADP, shortened fatty acids were formed in the mitochondria of liver, probably by the first reactions of β‐oxidation. In this case, the proportions of oleic acid and hexadecenoic acid were higher than with NADP alone. In the presence of carnitine and NADP, the level of the chain‐shortening reaction did not differ from that observed with NADP alone. It appears, therefore, that the activated erucic acid is mainly directed towards shortening reactions and not towards transfer reactions across the mitochondrial membranes.
The effects of phenobarbital on biliary lipid metabolism in cholesterol gallstone subjects
Authors: Redinger R. N. 
Published: November 2006

AbstractThe effect of 1.7–2.2 mg/day oral phenobarbital over short (1 MO) and long term (6–24 MO) treatment on primary bile acid (BA) secretion, composition, synthesis, pool size, and enterohepatic cycling rates as well as phospholipid (PL) and cholesterol (C) secretion rates and biliary composition was determined in 12 asymptomatic cholesterol gallstone subjects while 5 normals had only short term studies. Phenobarbital enhanced BA and C secretion (BA‐636±166 to 2110±382 mg/hr, p<0.001 and C‐42±5 to 224±48 mg/hr, p<0.001) and BA cycling rate in all subjects studied during stimulated enterohepatic circulation but, during fasting, it only enhanced BA secretion (451±129 vs. 759±159 mg/hr, p<0.05) in gallstone subjects. Cholic acid (CA) production rate (171±28 to 395±9 mg/hr, p<0.05) and pool size (727±80 to 1209±132 mg/hr, p<0.05) were increased during long term treatment of gallstone subjects, while the proportion of CA in bile and deoxycholic acid (DCA) in feces increased. Treatment decreased biliary cholesterol from supersaturated to saturated levels (9.5±0.6 vs. 6.1±0.9 moles%, p<0.02) in all fasting gallstone subjects and decreased cholesterol crystal loads during long term treatment; but, while prohibiting gallstone growth, it did not affect stone dissolution over 24 month's treatment. Phenobarbital also failed to affect biliary lipid composition or bile acid pool size in short term treatment of normals. Thus, phenobarbital affected hepatic metabolism of CA by enhancing production rate, secretion, and pool size; and in testinal metabolism of both CA and chenodeoxycholic (CDC) acids by increasing their cycling rates. Phenobarbital may have failed to produce stone dissolution by enhancing CA production and pool size more than that of CDC.
The content and composition of sterols and sterol esters in sunflower and poppy seed oils
Authors: Johansson Anna 
Published: November 2006

AbstractThe composition and proportion of free sterols and sterol esters in crude sunflower and poppy seed oils were determined, using preparative thin layer chromatography followed by gas chromatography with cholesterol as an internal standard. Free sterols and sterol esters were also isolated in a liquid fraction obtained by low temperature crystallization (−80 C) of the oils and enriched with minor lipid classes. This enrichment procedure provided a liquid fraction suitable for studies of minor components in the oils. However, selectivity towards sterol esters was observed since sterols esterified to very long chain fatty acids (C20–C24) were preferentially retained in the precipitate. The proportions of free and esterified sterols were found to be 0.34 and 0.28%, respectively, in the sunflower oil, whereas the corresponding figures for poppy seed oil were 0.33% and 0.05%. Sunflower oil was characterized by a relatively high percentage of Δ7‐sterols, preferentially obtained in the esterified fraction, and by very long chain saturated fatty acids of sterol esters. The sterols in poppy seed oil were composed almost entirely of campesterol, stigmasterol, sitosterol and Δ5‐avenasterol, although their percentage distributions were remarkably different in the free and esterified fraction.
Distribution of hexadecenoic, octadecenoic and octadecadienoic acid isomers in human tissue lipids
Authors: Adlof R. O. , Emken E. A. 
Published: November 2006

AbstractThetrans 16∶1, 18∶1 and 18∶2 fatty acid composition of various human organ lipids was studied to determine if isomers accumulated in specific tissues. “Trans” isomers are defined as those fatty acids containing one or moretrans double bonds. Adipose, kidney, brain, heart and liver tissue lipids were analyzed. Gas chromatography with a 100‐SP2560 capillary column was used to characterize the various positional and/or geometrical isomers. The distribution ofrans 16∶1 and 18∶1 isomers ranged from 0.3% in the brain to 4.0% in adipose tissue, whiletrans 18∶2 isomers ranged from 0.0% in the brain to 0.4% in adipose tissue. Notrans 18∶3 isomers were detected. Positional isomer ratios forcis 16∶1 (Δ9 vs Δ7) andcis 18∶1 (Δ11 vs Δ9) were also determined. Since these ratios are reproducible from one individual to the next, they might be useful for diagnosis of human metabolic disorders.
Prostaglandin‐like substances formed during autoxidation of methyl linolenate
Authors: Nakamura Takashi 
Published: November 2006

AbstractProstaglandin‐like substances other than 3‐(2‐ethyl‐5‐hydroxy‐3‐oxo)‐cyclopentanyl‐2‐propenal (compound I), which upon reacting with amino acids form reddish pigments, were purified, and their chemical structures were determined. Three red pigment‐forming substances (RPS) in autoxidized methyl linolenate were purified successively by gel chromatography on Sephadex LH‐20, column chromatography and thin layer chromatography on Silica Gel 60, and by high performance liquid chromatography on μ‐Porasil. IR spectra of the RPS showed the absorption of an ester group (νC=O 1730 cm−1 in CHCl3) and of a longer branched chain (νC‐H 2800–3100 cm−1), in addition to the absorption bands observed in compound I. Electron impact mass spectra of the trimethylsilyl ethers obtained after reduction with NaBH4 and NaBD4 were analyzed in detail and compared with those of compound I. The structures of the RPS were identified as stereoisomeric methyl 8‐[2‐(2‐formylvinyl)‐3‐hydroxy‐5‐oxo‐cyclopentanyl]‐octanoates derived from methyl 12‐hydroperoxy‐linolenate.
Rat hepatocyte plasma membrane acyl:CoA synthetase activity
Authors: Davidson B. C. , Cantrill R. C. 
Published: November 2006

AbstractThe presence of long chain acyl:CoA synthetases in mammalian microsomes and mitochondria has been established previously by Aas (Biochim. Biophys. Acta 231, 32–47 [1971]). The presence of a plasma membrane‐associated enzyme was investigated in rat hepatocyte plasma membranes, where an enzyme exhibiting high activity and with a preferred substrate of 18‐carbon chain length was discovered. The results are consistent with the presence of a single enzyme. The effect of the degree of unsaturation of the fatty acid substrates was not as pronounced as that arising from the length of the carbon chain. The pattern of substrate preference of the enzyme was ω3 polyenoic fatty acids >ω6 polyenoic acids >ω9 monoenoic acids > saturated acids. This may relate to the similar substrate preference pattern exhibited by the fatty acyl desaturase enzymes. The role played by long chain acyl:CoA synthetase in hepatocyte metabolism is uncertain, but it may relate to the incorporation of polyenoic fatty acids from the circulation into cell membranes and the trapping of other fatty acids within the cell for further metabolism.
A hydrophilic bile acid effects partial dissolution of cholesterol gallstones in the prairie dog
Authors: Cohen Bertram I. , Mosbach Erwin H. , McSherry Charles K. , Rzigalinski Beverly , Kuroki Syoji 
Published: November 2006

AbstractGallstone formation and dissolution were studied in a prairie dog model of cholesterol (CH) cholelithiasis. Gallstones were induced in 49 prairie dogs by feeding 1.2% CH in a nutritionally adequate semisynthetic diet for 6 wk (period 1). At 6 wk, gallstones had developed in all animals examined. The diets were modified by reducing the amounts of CH to 0.4, 0.2, 0.1 and 0.0% (diets 1–4); hyodeoxycholic acid (HDA; 30 mg/kg/day) was added to these diets (diets 5–8). All animals were fed the modified experimental diets for an additional 8 wk (period 2). At week 14, spontaneous gallstone dissolution had not occurred, even in the groups given no added dietary CH during period 2 (group 4). Addition of HDA to the diet tended to reduce the incidence of biliary CH crystals and the size and number of CH gallstones. Biliary CH remained elevated and the lithogenic indices in all groups were found to be greater than 1.0 at the end of the experiment. Liver and plasma CH levels tended to be lower in the groups fed HDA. In these groups, HDA and 6βHDA became the major biliary bile acids. This study demonstrates that HDA achieved partial dissolution of gallstones in bile supersaturated with CH.
Inhibition of the antidiuretic hormone hydroosmotic response by phospholipids and phospholipid metabolites
Authors: Tarapoom Nimman , Royce Ron , Yorio Thomas 
Published: November 2006

AbstractPhospholipid metabolities and phospholipids containing arachidonic acid (AA) inhibited the antidiuretic hormone (ADH)‐induced increase in transepithelial water flow in the toad urinary bladder, but had no effect on basal water flow when added to the serosal bathing solution. Other fatty acid‐substituted phospholipid metabolites had no effect on osmotic water movement in the presence or absence of ADH. Indomethacin attenuated the inhibitory effects of the AA containing phospholipid metabolities (PMAA), suggesting that the PMAA response required AA release and prostaglandin (PG) formation. PMAA increased PGE formation as measured by radioimmunoassay. PG have been reported to inhibit ADH‐stimulated water flow by inhibiting adenylcyclase. PGE2 (10−8 M) had no effect on cyclic AMP‐stimulated water flow, whereas exogenous AA and PMAA attenuated the hydroosmotic response to added cyclic AMP. Indomethacin only partially reversed the inhibition by AA of the cyclic AMP‐associated water movement, suggesting that the inhibition by AA and PMAA may involve other metabolites of AA than PG.PG and the AA cascade have been implicated as cellular modulators of the ADH hydroosmotic response. The present results offer additional support to the theory that this system may regulate the intracellular events that are transduced following receptor activation by ADH.
Lack of regioselectivity in formation of oxohydroxyoctadecenoic acids from the 9‐ or 13‐hydroperoxide of linoleic acid
Authors: Gardner H. W. , Kleiman R. 
Published: November 2006

AbstractEither 9‐hydroperoxy‐trans‐10,cis‐12‐octadecadienoic acid or 13‐hydroperoxy‐cis‐9,trans‐11‐octadecadienoic acid was treated with the catalyst, cysteine‐FeCl3, in the presence of oxygen. Oxohydroxyoctadecenoic acids were among the many products formed as a result of hydroperoxide decomposition. A mixture of 9(13)‐oxo‐13(9)‐hydroxy‐trans‐11(10)‐octadecenoic acids (δ‐ketols) was produced from either isomeric hydroperoxide. The formation of isomeric δ‐ketols from 9‐hydroxy‐trans‐12,13‐epoxy‐trans‐10‐octadecenoic acid (epoxyol), a known product of 13‐hydroperoxy‐cis‐9,trans‐11‐octadecadienoic acid decomposition, implies that the epoxyol is an intermediate. The mechanism was elucidated by the facile conversion of the epoxyol (methyl ester_ to methyl 9(13)‐oxo‐13(9)‐hydroxy‐trans‐11(10)‐octadecenoates with a Lewis acid, BF3‐etherate.
A simplified procedure for the determination of betaine in liver
Authors: Barak A. J. , Tuma D. J. 
Published: November 2006

AbstractA convenient procedure for the determination of hepatic betaine levels is described. The method takes advantage of ethanol precipitation to rid acidified tissue extracts of interfering substances. Betaine is reacted with potassium triiodide to form betaine periodide, which is selectively precipitated via pH adjustment. The precipitate of betaine periodide is dissolved in ethylene dichloride and measured spectrophotometrically. The method is specific, accurate, and simple and showed recoveries of from 97 to 103% at two different levels of added betaine. The applicability of the method was shown when it was demonstrated that diets containing different amounts of choline influenced levels of hepatic betaine.
pH gradient electrophoresis and isoelectric focusing of lipoproteins on agarose bead thin layers
Authors: Vost A. , Pocock D. M. ‐E. , Pleet S. 
Published: November 2006

AbstractA new method of isoelectric focusing (IEF) and pH gradient electrophoresis, using thin layers of agarose gel beads, was devised to investigate chylomicrons and very low density lipoproteins (VLDL). pH gradient stability and cathodal gradient drift were similar to those of polyacrylamide gel IEF, and linearity of gradients was maintained for 23 hr. Chylomicrons and VLDL were detectable without staining. Chylomicrons from human serum and from rat lymph migrated in this system. Rat lymph chylomicrons, obtained by ultracentrifugation, migrated in several discrete bands, and this heterogeneity of rat chylomicrons was confirmed by electron microscopic demonstration of chylomicrons in each band. This new technique has permitted the first measurement of isoelectric points of some lipoproteins in the ultracentrifuged fraction of human serum chylomicrons and the first separation of multiple discrete fractions of ultracentrifuged lymph chylomicrons.
Identification of ergosta‐8,24(28)‐dien‐3β,6α‐diol in A Δ8 → Δ7 sterol isomerase‐blocked yeast mutantsterol isomerase‐blocked yeast mutant
Authors: Pierce A. M. , Pierce H. D. , Unrau A. M. , Oehlschlager A. C. , Woods R. A. 
Published: November 2006

AbstractIn addition to the monohydroxysterols found in the Δ8 → Δ7 isomerase‐blockedSaccharomyces cerevisiae mutanterg 2, a novel dihydroxysterol, ergosta‐8,24(28)‐dien‐3β,6α‐diol, was isolated. This sterol accumulated to the extent of 2.1% of the total sterol fraction when this mutant was treated with 23‐azacholesterol, a known inhibitor of the 24‐methylene‐sterol‐24(28)‐reductase.
Inhibition of hepatic lipogenesis by 2‐tetradecylglycidic acid
Authors: McCune Sylvia A. , Nomura Takahide , Harris Robert A. 
Published: November 2006

Abstract2‐Tetradecylglycidic acid (TDGA), a hypoglycemic agent, has been found to be a very effective inhibitor of de novo fatty acid synthesis by isolated hepatocytes. A comparison was made between the effectiveness of TDGA and 5‐(tetradecyloxy)‐2‐furoic acid (TOFA), a hypolipidemic agent, on the metabolic processes of isolated hepatocytes. These compounds are structurally related and both inhibit fatty acid synthesis; however, they have opposite effects from each other on the oxidation and esterification of fatty acids. TDGA inhibits whereas TOFA stimulates fatty acid oxidation. TDGA stimulates whereas TOFA inhibits fatty acid esterification.
Composition and biosynthesis of fatty acids inPyramimonas grossii
Authors: Pollero Ricardo J. , Brenner Rodolfo R. , Gayoso Ana María 
Published: November 2006

AbstractThe green algaPyramimonas grossii orginating in the coastal waters of the Atlantic Ocean Argentina was subcultured until a monoalgal culture was obtained. The fatty acid composition of the alga grown in a mineral medium at 12 C was determined by gas liquid chromatography (GLC) on 2 columns. The major fatty acids were oleic, linoleic, palmitic and α‐linolenic acids, but the 20‐carbon polyunsaturated acids, 20∶4ω6 and 20∶5ω3, respectively, belonging to the linoleic and α‐linolenic series, were also found. Incubation with [14C] oleate, [14C] acetate, [14C] linoleate and [14C] α‐linolenate suggests that linoleate is not directly converted to α‐linolenate. [14C] Acetate was easily converted to palmitic, palmitoleic and oleic acids. However, after 48 hr of incubation, only traces of radioactivity were detected in linoleic acid and no label was found in α‐linolenic acid.
The removal of peroxides from phosphatidylcholine preparations
Authors: Poghossian G. G. , Nalbandyan R. M. 
Published: November 2006

AbstractA major portion of the peroxides from egg yolk phosphatidylcholine preparations can be removed by filtration through Sephadex LH‐20, by repetitive suspending of phosphatidylcholine preparations in water, precipitation by acetone and brief incubation of the lipid with superoxide dismutase.
A convenient spectrophotometric assay for phospholipase D usingp‐nitrophenyl‐phosphocholine as substrate
Authors: Gupta Munishwar N. , Wold Finn 
Published: November 2006

AbstractA simple assay for plant phospholipase D is described. The enzyme hydrolyzesp‐nitrophenyl‐phosphocholine top‐nitrophenyl phosphate, which in the presence of an acid phosphatase generatesp‐nitrophenol (a chromogenic compound). Thus,p‐nitrophenylphosphocholine can be used for assay of phospholipase D in sources that do not also contain high levels of phospholipase C.
Major unsaturated cuticular hydrocarbons of the field crickets,Gryllus pennsylvanicus andNemobius fasciatus
Authors: Warthen J. D. , Uebel E. C. 
Published: November 2006

AbstractAdult male field crickets,Gryllus pennsylvanicus Burmeister, have more unsaturated cuticular hydrocarbons than adult females, and each has more unsaturates than last‐instar male and female nymphs. The 2 most abundant unsaturated hydrocarbons from each adult were (Z)‐7‐nonacosene and (Z,Z)‐6,22‐nonacosadiene. Last‐instar male nymphal field crickets,Nemobius fasciatus (De Geer), were almost devoid of cuticular alkenes compared to last instar female nymphs and adult males and females. The major unsaturated hydrocarbon from each was (Z,Z)‐6,9‐pentacosadiene.
Effect of dietary fat on the fluidity of platelet membranes
Authors: Berlin Elliott , Matusik Edward J. , Young Calvert 
Published: November 2006

AbstractDietary fat type was reflected in the phospholipid fatty acid composition of the plasma membrane of rabbit platelets and apparently controlled the fluidity of these membranes. Rabbits were maintained for 6 months on diets that varied in stearic and polyunsaturated fatty acids and thus had different potentials for thrombosis. Microviscosities at 37 C, calculated from the anisotropy of fluorescence from the probe 1,6‐diphenyl‐1,3,5‐hexatriene, were 3.5, 3.4, 2.8 and 2.2. poise for platelet membranes isolated from rabbits whose only source of dietary fat was cocoa butter, milkfat, coconut oil, or corn oil, respectively. The relative fluidities of the membrane isolates were correlated with the polyunsaturated fatty acid contents of the membrane phospholipids.
Fatty acid synthesis in the oil palm (Elaeis guineensis): Incorporation of acetate by tissue slices of the developing fruit
Authors: Oo Khaik‐Cheang , Teh Sau‐Keen , Khor Hun‐Teik , Ong Augustine S. H. 
Published: November 2006

AbstractOil palm (E. guineensis) fruits at three stages of development were studied. At week 12–13 after anthesis, the endosperm had started accumulating oil and tissue slices incorporated [1‐14C] acetate into fatty acids which resembled those found in the mature endosperm. The mesocarp contained very little oil and incorporated acetate into polar lipids. At week 16–17, the mesocarp started to accumulate oil; this was reflected in the [14C] lipid products from acetate incubation. At or just prior to this stage, an increase in the endogenous linoleic and linolenic acid content and the increase in fruit size indicated cellular growth in the mesocarp tissue. At week 20–21 the fruit was ripe, and both endosperm and mesocarp tissues were filled with storage oil. [14C] Fatty acids synthesized from acetate by mesocarp slices at this stage were the same as the endogenous storage fatty acids in bothE. guineensis andE. oleifera. A very weak fatty acid synthesizing activity was seen in the mature endosperm, but the products had no relationship to the storage lipid.