bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of the ratio of polyunsaturated and monounsaturated fatty acid to saturated fatty acid on rat plasma and liver lipid concentrations
Authors: Chang Nai Wen , Huang Po Chao 
Published: November 2006

AbstractThe effects of dietary monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid+MUFA/saturated fatty acid (PUFA+MUFA/SFA) ratio on plasma and liver lipid concentrations were studied. In experiment I, when rats were fed with 40% fat (energy%, PUFA/SFA ratio 1.0) and 1% (w/w) cholesterol (C) diets for 21 d, a large amount of MUFA (28.1 energy%, PUFA+MUFA/SFA=5.7) in the diet was found to increase the plasma total C, triacylglycerol (TAG), and phospholipid (PL) as compared with the low‐MUFA diet (7.0 energy%, PUFA+MUFA/SFA=1.4). The plasma very low density lipoprotein (VLDL)‐C, VLDL‐TAG, VLDL‐PL, and low density lipoprotein (LDL)‐C increased significantly in the high‐MUFA diet group, but high density lipoprotein (HDL)‐C did not change significantly. The high‐MUFA diet resulted in greater accumulation of liver C but lesser accumulation of TAG. In experiment II, when dietary SFA was fixed at a certain level (13.2 energy%; PUFA+MUFA/SFA=2.0), rats given a larger amount of MUFA (23.1 energy%; PUFA/MUFA=0.2; MUFA/SFA=1.8) showed higher plasma and liver C levels than did the low‐MUFA diet (7.7 energy%; PUFA/MUFA=2.5; MUFA/SFA=0.6). When PUFA was fixed at a certain level (24.4 energy%), there was not a significant difference in the plasma C level between the high‐and low‐MUFA dietary groups (PUFA+MUFA/SFA=4.8 and 8.4), but the higher PUFA+MUFA/SFA diet, which was high in MUFA/SFA ratio, significantly decreased the plasma HDL‐C and TAG levels. However, when MUFA content was fixed at a certain level (16.4 energy%), no significant difference was observed between the two groups with different PUFA/SFA ratios of 0.2 and 4.1, but liver C level was raised in the higher PUFA/SFA diet. It appears that the PUFA/SFA ratio alone is unsuitable to predict the change of plasma C level, because a large amount of dietary MUFA may lead to an increase of plasma and liver lipids in rats. It seems that the prerequisites for keeping low plasma and liver C are (i) low MUFA/SFA ratio, (ii) high PUFA/MUFA ratio, and (iii) PUFA+MUFA/SFA ratio not to exceed 2.
Lipid‐lowering effects of WAY‐121,898, an inhibitor of pancreatic cholesteryl ester hydrolase
Authors: Krause Brian R. , Sliskovic Drago R. , Anderson Maureen , Homan Reynold 
Published: November 2006

AbstractWAY‐121,898 is an inhibitor of pancreatic cholesteryl ester hydrolase (pCEH). After confirming its in vitro potency and relative lack of a major effect on acyl‐CoA:cholesterol acyltransferase (ACAT), it was found that this compound lowers plasma cholesterol in cholesterol‐fed, but not chow‐fed, rats. Measures of liver cholesteryl ester content and the direct determination of cholesterol absorption (lymph‐fistula model) show that inhibition of cholesterol absorption is at least one mechanism for the observed cholesterol lowering. However, WAY‐121,898 was also active when administered parenterally to cholesterol‐fed rats, and in cholesterol‐fed hamsters cholesterol‐lowering occurred with oral dosing despite no change in cholesterol absorption, suggesting other modes of action possibly relating to inhibition of liver CEH. Combination treatment in cholesterol‐fed rats with the ACAT inhibitor CI‐976 resulted in a greater‐than‐additive reduction in plasma cholesterol, imlying that both pCEH and ACAT may play a role in cholesterol absorption in this species. In rabbits, WAY‐121,898 prevented the rise in plasma cholesterol due to the feeding of cholesteryl ester but not in rabbits fed (free) cholesterol. In guinea pigs, the compound induced an increase in adrenal cholesteryl ester mass. Taken together, the overall profile in these animal models suggests that WAY‐121,898 inhibits more than just the intestinal (lumenal) pCEH, and that the role of this enzyme in cholesterol metabolism may be different within and across species, the former depending upon the dietary cholesterol load.
Effect of n−3 fatty acid supplementation on lipid peroxidation and protein aggregation in rat erythrocyte membranes
Authors: Ando Ken , Nagata Kunihide , Beppu Masatoshi , Kikugawa Kiyomi , Kawabata Terue , Hasegawa Kyoko , Suzuki Masao 
Published: November 2006

AbstractHuman erythrocytes in the circulation undergo dynamic oxidative damage involving membrane lipid peroxidation and protein aggregation during aging. The present study was undertaken to determine the effect of n−3 fatty acid supplementation on lipid peroxidation and protein aggregation in the circulation and also the in vitro susceptibility of rat erythrocyte membranes to oxidative damage. Wistar male rats were fed a diet containing n−6 fatty acid‐rich safflower oil or n−3 fatty acid‐rich fish oil with an equal amount of vitamin E for 6 wk. n−3 Fatty acid content in erythrocyte membranes of rats fed fish oil was significantly higher than that of rats fed safflower oil. The degree of membrane lipid peroxidation and protein aggregation of rats fed fish oil was not significantly higher than that of rats fed safflower oil when the amounts of phospholipid hydroper‐oxides, thiobarbituric acid‐reactive substances, and detergent‐insoluble protein aggregates were measured. When isolated erythrocytes were oxidized under aerobic conditions in the presence of Fe(III), the degree of membrane lipid peroxidation of erythrocytes from rats fed fish oil was increased to a greater extent than that of rats fed safflower oil, whereas the degree of membrane protein aggregation of both groups was increased in a similar extent. Hence, n−3 fatty acid supplementation did not affect lipid peroxidation and protein aggregation in membranes of circulating rat erythrocytes, and the supplementation increased the susceptibility of isolated erythrocytes to lipid peroxidation, but not to protein aggregation, under the aerobic conditions. If a sufficient amount of vitamin E is supplied, n−3 fatty acid supplementation may give no undesirable oxidative effects on rat erythrocytes in the circulation.
Modification of milk formula to enhance accretion of long‐chain n−6 and n−3 polyunsaturated fatty acids in artificially reared infant rats
Authors: Yeh Yu‐Yan , Yeh Shaw‐Mei , Lien Eric L. 
Published: November 2006

AbstractArtificially reared infant rats were used to determine the effects of long‐chain polyunsaturated fatty acid (LCP‐UFA) supplementation on blood and tissue concentrations of arachidonic acid (AA) and docosahexaenoic acid (DHA). Beginning at 7 d of age, infant rats were fed for 10 d with rat milk formulas supplemented with AA at 0,0.5 and 1.0%, or supplemented with DHA at 0,0.5 and 1.0% of total fatty acid. The supplementation of AA increased accretion of the fatty acid in tissue and blood phospholipids with a maximum increase of 9% in brain, 15% in liver, 25% in erythrocytes, and 43% in plasma above the values of unsupplemented infant rats. Rat milk formula containing 1.0% of AA had no added benefits over that containing 0.5% of AA. The supplementation of DHA increased phospholipid DHA by a maximum of 24% in brain, 87% in liver, 54% in erythrocytes, and 360% in plasma above the unsupplemented control. The increase in tissue and blood DHA was concentration‐dependent on formula fatty acid. Brain phosphatidylcholine and phosphatidylethanolamine were similarly enriched with AA and DHA by supplementation of the corresponding fatty acids. In general the observed increase of AA was accompanied by a decrease in 16:0, 18:1n−9, and/or 18:2n−6, whereas the increased DHA was associated with a reduction of 18:1n−9, 18:2n−6, and/or 20:4n−6. Clearly, infant rats were more responsive to DHA than AA supplementation, suggesting a great potential of dietary manipulation to alter tissue DHA concentrations. However, the supplementation of DHA significantly decreased tissue and blood AA/DHA ratios (wt%/wt%), whereas there was little or no change in the ratio by AA supplementation. Although the physiological implications of the levels of AA and DHA, and AA/DHA ratios achieved under the present experimental conditions are not readily known, the findings suggest that artificial rearing could provide a suitable model to investigate LCPUFA requirements using various sources of AA and DHA in rats.
Simultaneous quantitation of ceramides and 1,2‐diacylglycerol in tissues by latroscan thin‐layer chromatography‐flame‐ionization detection
Authors: Okumura Kenji , Hayashi Kazunori , Morishima Itsuro , Murase Kichiro , Matsui Hideo , Toki Yukio , Ito Takayuki 
Published: November 2006

AbstractCeramides and 1,2‐diacylglycerol have been demonstrated in intracellular signaling pathways. A method of simultaneous mass determination of ceramides and 1,2‐diacylglycerol in tissues was developed using the latroscan which combines thin layer chromatography and flame ionization detection (TLC/FID) techniques. Because of relatively low amounts of these components in tissues, the fraction of nonpolar lipids, which included ceramides and glycerides, was eluted with chloroform/acetone mixture (3∶1, vol/vol) through a silicic acid column to eliminate the polar phospholipids. Development of Chromarods was carried out using three solvent systems in a four‐step development technique. The relationship of the peak area ratio to weight ratio compared with cholesteryl acetate added as an internal standard was linear. The amount of ceramides increased with incubation of rat heart homogenate and human erythrocyte membranes in the presence of sphingomyelinase (E.C. 3.1.4.12). The latroscan TLC/FID system provided a quick and reliable assessment of ceramides and 1,2‐diacylglycerol.
A gas chromatographic‐mass spectrometric method using a PoralPLOT column for the detection of hydroperoxide lyase in Chlorella pyrenoidosa
Authors: Nuñez Alberto , Foglia Thomas A. , Piazza George J. 
Published: November 2006

AbstractA gas chromatographic‐mass spectrometric (GC‐MS) method using a PoraPLOT Q column was developed for the analysis and identification of the volatile products produced by the action of hydroperoxide lyase (HPLS) upon 13‐hydroperoxylinoleic or 13‐hydroperoxylinolenic acids. The developed procedure required no derivatization, was not affected by the presence of water, did not require cryogenic conditions to be maintained during injection, and allowed for the quantiation of most products. An acetone powder preparation of Chlorella pyrenoidosa cells was triturated with borate buffer pH=8.0, and the mixture centrifuged at 12,000×g. The supernatant and pellet were assayed for HPLS activity by GC‐MS analysis of the volatile products given by linoleic acid hydroperoxide. The data showed that the majority of HPLS activity resides in the pellet fraction, and that the primary volatile component was pentane, with smaller amounts of 2‐(Z)‐pentene and 1‐pentene being produced. The fact that HPLS activity resides in the water‐insoluble fraction of the acetone powder suggests that HPLS from Chlorella is a membrane‐associated enzyme. This investigation also determined that a spectrophotometric assay using alcohol dehydrogenase for measuring HPLS activity was not specific, but measured enzymatic activity other than HPLS.
Psyllium, not pectin or guar gum, alters lipoprotein and biliary bile acid composition and fecal sterol excretion in the hamster
Authors: Trautwein Elke A. , Rieckhoff Dörte , Kunath‐Rau Angelika , Erbersdobler Helmut F. 
Published: November 2006

AbstractDifferent soluble dietary fibers known to alter cholesterol metabolism were fed to golden Syrian hamsters, and their specific impact on lipoproteins, biliary bile acid profile, and fecal sterol excretion was evaluated. Semipurified diets containing 20% fat; 0.12% cholesterol; and 8% of psyllium (PSY); high (hePE) and low (lePE) esterified pectin; or high (hvGG) and low (lvGG) viscous guar gum were fed for 5 wk. Compared to control, PSY caused a significant reduction in plasma cholesterol (2.9±0.5 vs. 5.5±0.5 mmol/L), whereas hePE, lePE, hvGG, or lvGG had no apparent effect on plasma lipids. Hepatic total and esterified cholesterol were substantially decreased with PSY, pectin and guar gum, whereby PSY produced the most pronounced effect. Distinctive changes existed in the bile acid profile related to the different fibers. In contrast to pectin and guar gum, PSY caused a significant increase in the cholate:chenodeoxycholate and the glycine:taurine conjugation ratio. Pectin and guar gum did not alter daily fecal neutral sterol excretion while PSY caused a 90% increase due to a higher fecal output. Daily fecal bile acid excretion and total fecal bile acid concentration were significantly increased by PSY, whereas hePE, lePE, hvGG, and lvGG revealed no or only minor effects. Taken together, the disparate hypocholesterolemic effects of PSY, pectin, and guar gum on cholesterol and bile acid metabolism in the hamster are possibly related to different physicochemical properties, e.g., viscosity and susceptibility to fermentation, affecting the fiber‐mediated action in the intestine.
Mechanism of lower oxidizability of eicosapentaenoate than linoleate in aqueous micelles. II. Effect of antioxidants
Authors: Yazu Kazumasa , Yamamoto Yorihiro , Niki Etsuo , Miki Keiji , Ukegawa Koji 
Published: November 2006

AbstractWe have reported that the peroxyl radicals derived from methyl eicosapentaenoate (20:5n‐3) are more polar than those from methyl linoleate (18:2n‐6) since the former peroxyl radicals have at least two molecules of oxygen in a molecule while the latter peroxyl radical has one. This lowers the oxidizability for 20:5n‐3 in aqueous Triton X‐100 micelles by enhancing the termination reaction rate for peroxyl radicals and by reducing the rate of propagation since there may be more polar peroxyl radicals derived from 20:5n‐3 at the surface than within the micelle core. In this study, we measured the effect of three antioxidants, di‐tert‐butyl‐4‐methylphenol (BHT), 2,2,5,7,8‐pentamethyl‐6‐chromanol (PMC) and 2‐carboxy‐2,5,7,8‐tetramethyl‐6‐chromanol (Trolox), on the oxidation of lipids in aqueous micelle. Antioxidants give a clear induction period during oxidation of 18:2n‐6 initiated with a water‐soluble radical initiator, and its induction length decreases in the order of BHT>PMC>Trolox. This is consistent with the proposed location of three antioxidants: being in the core of micelle, at the surface, or in aqueous phase, respectively. However, BHT does not inhibit the oxidation of 20:5n‐3 efficiently, and its rate of oxidation is slower than that observed in the oxidation of 18:2n‐6, supporting the idea that polar peroxyl radicals derived from 20:5n‐3 are preferentially located at the surface of the micelle. Similar results were obtained when oxidation was initiated with a lipid‐soluble radical initiator except antioxidants had lesser effect on the oxidation rate of 20:5n‐3.
Partial purification and characterization of sphingosine N‐acyltransferase (ceramide synthase) from bovine liver mitochondrion‐rich fraction
Authors: Shimeno Hiroshi , Soeda Shinji , Sakamoto Masahiko , Kouchi Takeshi , Kowakame Takashi , Kihara Taro 
Published: November 2006

AbstractSphingosine N‐acyltransferase (ceramide synthase, E.C. 2.3.1.24) was solubilized from bovine liver mitochondrion‐rich fraction with n‐ocytl β‐d‐thioglucoside as the detergent and partially purified by sequential chromatography on columns of DE‐32, shingosine affinity, and Sepharose CL‐6B. The partially purified preparation migrated on SDS‐polyacrylamide gel electrophoresis as two major protein bands of 62 and 72 kDa. The molecular mass of the enzyme estimated by gel filtration was 240–260 kDa, suggesting that the partially purified enzyme is present in a subunit form or simply has an aggregative nature. The specific activity of the final preparation for the condensation of sphingosine with stearoyl‐CoA increased by 98.7‐fold compared with the starting material. The optimal pH value for the ceramide synthesis was 7.5. The partially purified enzyme had an apparent Km of 146 μM and a Vmax of 11.1 nmol/min/mg protein for stearoyl‐CoA. The Km and Vmax values toward sphingosine were 171 μM and 11.3 nmol/min/mg protein, respectively. Interestingly, sphinganine was also a good substrate for this enzyme, and the Km and Vmax values were 144 μM and 8.5 nmol/min/mg protein, respectively.
Fatty acid composition of bacteria associated with the toxic dinoflagellate Ostreopsis lenticularis and with caribbean Palythoa species
Authors: Carballeira Néstor M. , Emiliano Anastacio , Sostre Anthony , Restituyo José A. , González Ileana M. , Colon Gretchen M. , Tosteson Carmen G. , Tosteson Thomas R. 
Published: November 2006

AbstractThe fatty acid composition of a Pseudomonas sp. (Alteromonas) and its host, the dinoflagellate Ostreopsis lenticularis, vectors in ciguatera fish poisoning, has been studied. The major fatty acids in O. lenticularis were 16∶0, 20∶5n‐3, and 22∶6n‐3, but 18∶2n‐6, 18∶3n‐3, and 18∶n‐3 were also identified. In contrast to other dinoflagellates, 18∶5n‐3 was not detected in O. lenticularis. Even‐chain fatty acids such as 9–16∶1, 11–18∶1, and 13–20∶1 predominated in the Pseudomonas sp. from O. lenticularis, but 16–20% of (E)‐11‐methyl‐12‐octadecenoic acid was also identified. The chirality of the latter was confirmed by total synthesis (28% overall yield) starting from oxacyclotridecan‐2‐one. The fatty acid compositions of two other Pseudomonas species, from the palytoxin‐producing zoanthids Palythoa mamillosa and P. caribdea, were also studied and were similar to that of the Pseudomonas sp. from O. lenticularis. The possibility of using some of these fatty acids as chemotaxonomic lipids in identifying marine animals that consume toxic dinoflagellates or zoanthids is discussed.
Effect of the degree of hydrogenation of dietary fish oil on the trans fatty acid content and enzymatic activity of rat hepatic microsomes
Authors: Morgado Nora , Galleguillos Angélica , Sanhueza Julio , Garrido Argelia , Nieto Susana , Valenzuela Alfonso 
Published: November 2006

AbstractThe degree of fat hydrogenation and the trans fatty acid content of the diet affect the fatty acid composition of membranes, and the amount and the activity of some membrane enzymes. We describe the effects of four isocaloric diets containing either sunflower oil (SO, 0% trans), fish oil (FO, 0.5% trans), partially hydrogenated fish oil (PHFO, 30% trans), or highly hydrogenated fish oil (HHFO, 3.6% trans) as fat sources on the lipid composition and the trans fatty acid content of rat hepatic microsomes. We also describe the effect of these diets on the cytochrome P‐450 content and on the aminopyrine N‐demethylase, aniline hydroxylase, and UDP‐glucuronyl transferase microsomal activities. Cytochrome P‐450 content was dependent on the degree of unsaturation of the diet, being higher for the FO‐containing diet and lower for the HHFO diet. Aminopyrine N‐demethylase activity also correlated with the degree of unsaturation of the diet as did the cytochrome P‐450 content did (FO>SO>PHFO>HHFO). Aniline hydroxylase activity appeared to be independent of the degree of unsaturation of the dietary fat, but correlated with the trans fatty acid content of the diet, which was also reflected in the trans content of the microsomal membranes. UDP‐glucuronyl transferase activity was higher for the FO‐containing diet than for the SO diet, showing intermediate values after the PHFO and HHFO diets.
Cyclic fatty acid monomers from dietary heated fats affect rat liver enzyme activity
Authors: Lamboni Courdjo , Sébédio Jean‐Louis , Perkins Edward G. 
Published: November 2006

AbstractThis study was conducted to investigate the effects of dietary cyclic fatty acid monomers (CFAM), contained in heated fat from a commercial deep‐fat frying operation, on rat liver enzyme activity. A partially hydrogenated soybean oil (PHSBO) used 7 d (7‐DH) for frying foodstuffs, or 0.15% methylated CFAM diets was fed to male weanling rats in comparison to a control group fed a nonheated PHSBO (NH) diet in a 10‐wk experiment. All diets were isocaloric with 15% fat. Animals fed either CFAM or 7‐DH diets showed increased hepatic content of cytochrome (cyt.) b5 and P450 and increased activity of (E.C. 1.6.2.4) NADPH‐cyt. P450 reductase in comparison to the control rats. In addition, the activities of (E.C. 2.3.1.21) carnitine palmitoyltransferase‐l and (E.C. 1.1.1.42) isocitrate dehydrogenase were significantly decreased when compared to that of rats fed the NH diet. A significantly depressed activity of (E.C. 1.1.1.49) glucose 6‐phosphate dehydrogenase was also observed for these animals compared to the control rats fed NH diet. Moreover, liver and microsomal proteins were significantly increased when CFAM or 7‐DH diets were fed to animals in comparison to controls while liver glycogen was decreased significantly in experimental groups of rats. The results obtained in this study indicate that the CFAM in the diet from either synthetic sources or used fats increase the activity of liver enzyme systems that detoxify them.
Magnesium silicate treatment of dietary heated fats: Effects on rat liver enzyme activity
Authors: Perkins Edward G. , Lamboni Courdjo 
Published: November 2006

AbstractIn an effort to reduce the deleterious nutritional effects of oxidation products generated in heated fats, a partially hydrogenated soybean oil (PHSBO) used 7 d (7‐DH) for frying foodstuffs was obtained from a commercial deep‐fat frying operation. The used fat was treated with magnesium silicate (T‐7DH). Isocaloric diets containing 15% of either 7‐DH or T‐7‐DH fats were prepared and fed to male weanling rats for 10 wk in a pair‐feeding experiment and compared to control rats fed nonheated PHSBO (NH). Animals fed the 7‐DH diet showed higher liver enzyme cytochrome b5 and P450 activity than the T‐7DH diet compared to the NH group, suggesting a positive effect of the treatment. These results suggested the presence of lower amounts of harmful compounds in the diet containing the heated used oil which had been treated with the active adsorbent.
Distribution of α‐and γ‐tocopherols in Atlantic salmon (Salmo salar) tissues
Authors: Parazo Monina P. M. , Lall Santosh P. , Castell John D. , Ackman Robert G. 
Published: November 2006

AbstractGroups of Atlantic salmon parr (mean initial weight 9.5 g) were fed three diets, the first containing no tocopherol supplement, the others supplemented with either all‐rac‐α‐tocopherol (A‐T) or RRR‐γ‐tocopherol (G‐T). Tocopherol concentrations in the liver, serum, testes, kidney, brain, gill, muscle, and perivisceral fat were measured after 36 wk. Despite a higher dietary intake of G‐T, compared to A‐T, deposition of γ‐tocopherol (γT) was less efficient than of α‐tocopherol (αT) in most tissues except in the perivisceral fat, an adipose tissue. In fish fed the G‐T diet, the γT/αT ratio was highest in the perivisceral fat and lowest in the liver, indicating that the liver is the most discriminatory organ for retaining αT as compared to γT, and the perivisceral fat is more suitable for the storage of γT. A negative correlation (P<0.01) was observed between the γT/αT ratio and the corresponding tissue phospholipid content, suggesting that γT is less efficiently deposited compared to αT in the phospholipid‐rich membranes which are presumed to be the functional site for lipid antioxidants in vivo. During restricted intake of αT, the liver and muscle exhibited the greatest reduction of this tocopherol among the tissues analyzed. The presence of minimal αT in the muscle from fish fed the tocopherol‐unsupplemented diet led to greater susceptibility to lipid peroxidation after frozen storage than was the case for muscle containing higher concentrations of either αT or γT. However, both αT and γT were effective stabilizers of salmon muscle lipids during frozen storage.