bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of 2‐(2,4‐dimethylphenyl)indan‐1,3‐dione on serum lipoprotein and lipid metabolism of rodents
Authors: Hall Iris H. , Murthy Akula R. K. , Day Patricia A. , Clavin John 
Published: November 2006

Abstract2‐(2,4‐Dimethylphenyl)indan‐1,3‐dione was shown to be a potent hypolipidemic agent in rodents, lowering significantly both serum cholesterol and triglyceride levels at 20 mg/kg/day. The agent in vivo inhibited the enzymatic activities of ATP‐dependent citrate lyase, acetyl‐CoA synthetase, cholesterol‐7α‐hydroxylase, acyl‐CoA cholesterol acyl transferase,sn‐glycerol‐3‐phosphate acyl transferase and phosphatidylate phosphohydrolase. Tissue lipid levels of liver and small intestine also were reduced by the agent. The rat serum lipoprotein lipid content was modulated by the drug, which should be favorable for the removable of cholesterol from peripheral tissue for conduction to the liver for clearance from the body. Low density lipoprotein (LDL) cholesterol levels were reduced after treatment, which suggests that the agent potentially reduces deposition of cholesterol in plaques. If chemotherapy for atherosclerosis is to be successful, then the high density lipoprotein (HDL) cholesterol level needs to be elevated more than 16% to 25%, the level produced by current hypolipidemic agents. 2‐(2,4‐Dimethylphenyl)‐indan‐1,3‐dione offers a 75% increase in HDL cholesterol levels and a 30% reduction of LDL cholesterol levels with a suppression of de novo synthesis of lipids and a reduction of tissue cholesterol deposition.
Reaction of cholesterol 5,6‐epoxides with simulated gastric juice
Authors: Maerker Gerhard , Nungesser Edwin H. , Bunick Frank J. 
Published: November 2006

AbstractCholesterol 5α,6α‐epoxide (α‐epoxide) and cholesterol 5β,6β‐epoxide (β‐epoxide) were individually suspended in simulated gastric juice (pH 1.2) at 37 C, and their reaction was followed by gradient high performance liquid chromatography (HPLC) with flame ionization (FID) detection. Both epoxides reacted rapidly in the aqueous acid medium. The α‐epoxide formed 6β‐chlorocholestane‐3β,5α‐diol (α‐chlorohydrin) and 5α‐cholestane‐3β,5,6β‐triol (triol), while the β‐epoxide formed 5α‐chlorocholestane‐3β,6β‐diol (β‐chlorohydrin) and triol. The isomeric chlorohydrins reacted further to form the triol. In mildly alkaline aqueous medium, each chlorohydrin reverted to the epoxide from which it was formed. The data suggest that both epoxides, which have been reported to have adverse health effects in animals, would be largely hydrolyzed in the stomach and to the triol, which also has been reported to have biological activity. The data furher suggest that residual chlorohydrins surviving stomach residence can be expected to revert to epoxide in the more alkaline intestinal environment.
Essential fatty acid pattern of glycerolipids in rat hepatocytes in primary culture and in coculture with rat liver epithelial cells
Authors: Pepin D. , Chambaz J. , Rissel M. Y. , Guillouzo A. , Bereziat G. 
Published: November 2006

AbstractThe linoleic acid content of phosphatidylethanolamine (PE), phosphatidylcholine (PC) and triglyceride (TG) rapidly fell in rat hepatocytes in primary culture up to four days and in coculture with liver epithelial cells up to eight days. At the same time, the level of polyunsaturated fatty acids (PUFA), especially arachidonic acid, remained constant in PE, slightly decreased in PC and dropped in TG. There was no variation of the nonessential PUFA, 20∶3n−9.Linoleic acid supplementation of cultures 24 hr before the harvest induced a rise in the linoleic acid level of the three lipid classes. Arachidonic acid remained constant in TG and only slightly decreased in PE and PC at day 4 of primary culture and day 8 of coculture. The level of 20∶3n−9 increased in PE and PC and much more in TG. This net increase in the arachidonic acid and 20∶3n−9 levels in TG could not be explained only by a transfer from the phospholipid pools of PUFA because the phospholipid content of hepatocytes and PUFA levels of phospholipids did not vary under linoleic supplementation. The low percentage of arachidonic acid in epithelial cells rules out any participation of these cells in the increase of arachidonic acid in supplemented cocultures.Triglycerides may act as a storage pool for plasma PUFA up to four days of primary culture and eight days of coculture. Besides, coculture seems more potent than primary culture to maintain the phospholipid level, to spare the essential PUFA in PE and to increase the TG synthesis in response to linoleic acid supplementation.
Absorption and transport of deuterium‐substituted 2R,4′R,8′R‐α‐tocopherol in human lipoproteins
Authors: Traber Maret G. , Ingold Keith U. , Burton Graham W. , Kayden Herbert J. 
Published: November 2006

AbstractOral administration of a single dose of tri‐ or hexadeuterium substituted 2R,4′R,8′R‐α‐tocopheryl acetate (d3‐ or d6‐α‐T‐Ac) to humans was used to follow the absorption and transport of vitamin E in plasma lipoproteins. Three hr after oral administration of d3‐α‐T‐Ac (15 mg) to 2 subjects, plasma levels of d3‐α‐T were detectable; these increased up to 10 hr, reached a plateau at 24 hr, then decreased. Following administration of d6‐α‐T‐Ac (15–16 mg) to 2 subjects, the percentage of deuterated tocopherol relative to the total tocopherol in chylomicrons increased more rapidly than the corresponding percentage in whole plasma. Chylomicrons and plasma lipoproteins were isolated from 2 additional subjects following administration of d3‐α‐T‐Ac (140 or 60 mg). The percentage of deuterated tocopherol relative to the total tocopherol increased most rapidly in chylomicrons, then in very low density lipoproteins (VLDL), followed by essentially identical increases in low and high density lipoproteins (LDL and HDL, respectively) and lastly, in the red blood cells. This pattern of appearance of deuterated tocopherol is consistent with the concept that newly absorbed vitamin E is secreted by the intestine into chylomicrons; subsequently, chylomicron remnants are taken up by the liver from which the vitamin E is secreted in VLDL. The metabolism of VLDL in the circulation results in the simultaneous delivery of vitamin E into LDL and HDL.
Effect of previous nutritional status on the formation of cholesterol gallstones in the prairie dog
Authors: Cohen Bertram I. , Mosbach Erwin H. , McSherry Charles K. 
Published: November 2006

AbstractIn the prairie dog model of cholesterol cholelithiasis, a high incidence of gallstones is achieved by feeding a semipurified lithogenic diet containing 0.4% cholesterol for 2 mo. On occasion, we noted a decrease in the percentage of animals with gallstones from 90–100% to 50–55%. To explain this phenomenon, we studied the effect of dietary history on gallstone formation. After weaning, animals were fed either rodent chow or alfalfa plus corn (mo 0–3) followed by a cross‐over experiment at mo 4–6. Gallstone formation then was studied by feeding the lithogenic diet from mo 7 to 8. At sacrifice, the incidences of gallstones, biliary lipids and tissue cholesterol levels were correlated with dietary history. The incidence of gallstones was 100% only in animals fed the alfalfa‐corn diet from weaning to 3 mo. In addition, the feeding of the alfalfa‐corn diet at mo 4–6 increased gallstone incidence from 65% to 86%. The lithogenic index of all groups was highest when the animals received only alfalfa‐corn prior to the lithogenic stimulus. The activity of hepatic HMG‐CoA reductase was elevated in animals fed alfalfa‐corn from weaning to 8 mo, suggesting that this diet stimulates hepatic cholesterol synthesis, leading to increased biliary cholesterol secretion. It is concluded that previous nutritional conditioning affects the incidence of gallstones. The prairie dog is a useful model of cholesterol cholelithiasis, but the dietary history of the animals plays an important role in lithogenesis.
Location of methyl branchings in fatty acids: Fatty acids in uropygial secretion of Shanghai Duck by GC‐MS of 4,4‐dimethyloxazoline derivatives
Authors: Yu Q. T. , Liu B. N. , Zhang J. Y. , Huang Z. H. 
Published: November 2006

Abstract2‐Substituted 4,4‐dimethyloxazolines (DMOX) have been found to be a useful alternative to the commonly used methyl esters for the localization of unsaturated bounds and other substituents in the fatty chain by mass spectrometry. The powerful directed fragmentation coupled with good gas chromatographic ability enables the structure elucidation of modified fatty acids in complex mixtures. Continuing our previous study, 76 out of a total of 86 fatty acids obtained from the preen gland wax of shanghai duck now have been identified by gas chromatography‐mass spectrometry (GC‐MS) of their oxazoline derivatives. The identification was based on the interpretation of the mass spectra and comparison with the spectra and equivalent chain lengths (ECL) of the corresponding methyl esters. Main components of this lipid mixture are straight chain fatty acids (8.22%), and 2‐, 4‐or 6‐monomethyl branched acids (53.69%), amounting to 61.91% of the total acid fraction. In addition, a large number of dimethyl‐substituted fatty acids (31.4%) also have been found. Typical mass spectra, which are easily recognizable and highly specific for fatty acids substituted at various positions, are presented and classified according to the structural feature of the chain.
Analysis of free malondialdehyde in photoirradiated corn oil and beef fat via a pyrazole derivative
Authors: Umano K. , Dennis K. J. , Shibamoto T. 
Published: November 2006

AbstractMalondialdehyde (MA) formed in linolenic acid, linoleic acid, corn oil and beef fat upon photoirradiation was determined by gas chromatography (GC). The MA produced was reacted with methylhydrazine to give 1‐methyl‐pyrazole and was subsequently analyzed on a GC equipped with a nitrogen‐phosphorus specific detector and a fused silica capillary column. MA values determined by this method correspond to free or unbound MA levels. Linolenic and linoleic acids produced 867 μg MA/g and 106 μg MA/g, respectively. Oleic and stearic acids did not produce detectable levels of MA upon photoirradiation. Amounts of MA produced after eight hour irradiations of corn oil and beef fat were 56.24 μg/g and 25.01 μg/g, respectively. Some photoreaction products in irradiated corn oil also were identified as methylhydrazine derivatives.
Formation of octadecadienoate dimers by soybean lipoxygenases
Authors: van der Heijdt Lambertus M. , van der Lecq Fridolin , Lachmansingh Anand , Versluis Kees , van der Kerk‐van Hoof Anca , Veldink Gerrit A. , Vliegenthart Johannes F. G. 
Published: November 2006

AbstractThe aim of this investigation was to determine whether the regioselectivity found for lipoxygenases in the formation of fatty acid hydroperoxides from linoleic acid is reflected in the formation of dimeric products in secondary reactions involving linoleic acid, product hydroperoxide and lipoxygenase. A method was therefore developed for the separation and identification of dimers formed by fusion of two linoleic acid radicals or a linoleic acid radical and linoleate. The method includes solid‐phase extraction, preparative separation of products by thin‐layer chromatography, derivatization to the corresponding fully hydrogenated methyl esters and capillary gas chromatography (GC) coupled with electron impact mass spectrometry. We present evidence that the formation of octadecadienoate dimers, during the secondary reaction of soybean lipoxygenase‐1 or lipoxygenase‐3, is a nonenzymic process that can be envisaged by nonspecific association of intermediate fatty acid radicals (L*) that have dissociated from the enzyme. We could show that the relative amounts of different octadecadienoate dimers formed remain unaltered, regard‐less of pH and type of soybean isoenzyme used. Quantitative analysis by GC showed that under the reaction conditions used, the formation of dimers branching at the 13‐position is preferred.
Age‐dependent accumulation of phosphatidylcholine hydroperoxide in the brain and liver of the rat
Authors: Miyazawa Teruo , Suzuki Toshihide , Fujimoto Kenshiro 
Published: November 2006

AbstractAge‐related changes in phosphatidylcholine hydroperoxide (PCOOH) content as an index for oxidative membrane lipid damage were determined by high‐performance liquid chromatography using chemiluminescence detection. Brain and liver PCOOH content increased significantly in male and female rats with age. The brain PCOOH content of male 18‐month‐old rats was 4.4 times that of 1‐month‐old rats, and that of female 18‐month‐old rats was 3.5 times that of 1‐month‐old females. The liver PCOOH content of the male 18‐month‐old rats was 9.3 times that of the 1‐month‐old; and of the famale 18‐month‐old rats was 4.7 times that of the 1‐month‐old. PCOOH levels in heart and lung did not show age dependency. In both brain and liver (but not in heart and lung), the phosphatidylcholine content significantly decreased upon aging. The results indicate that oxidative deterioration, such as phospholipid hydroperoxidation, is prevalent in the membrane lipids of brain and liver of the rat due to aging.
Modulation of phosphatidylcholine biosynthesis by peroxisome proliferating fatty acid analogues
Authors: Skorve Jon , Svardal Asbjørn M. , Mansoor Mohammed A. , Berge Rolf K. 
Published: November 2006

AbstractThe modulation of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) biosynthesis by sulfur‐substituted fatty acid analogues has been investigated in rats. We have compared the effects of two non‐β‐oxidizable fatty acid analogues, 3‐thiadicarboxylic acid and tetradecylthioacetic acid, which induce proliferation of peroxisomes, with those of the analogue tetradecylthiopropionic acid, which is a weak peroxisome proliferator. Repeated administration of 3‐thiadicarboxylic acid for seven days resulted in increased hepatic concentrations of both PC and PE, but the PC/PE ratio was decreased. PC synthesis was increased, as evidenced by increased incorporation of [3H]choline into PC and an increased activity of cytidinetriphosphate (CTP): phosphocholine cytidylyltransferase. This was accompanied by a reduction in the pool sizes of choline and phosphocholine. TheS‐adenosylmethione/S‐adenosylhomocysteine ratio (AdoMet/AdoHcy) was marginally affected, indicating no increase in the rate of methylation of PE to PC. Administration of tetradecylthioacetic acid also resulted in increased hepatic phospholipid levels, increased AdoMet/AdoHcy ratios and in slightly elevated activity of CTP:phosphocholine cytidylyltransferase. The most striking effect observed after tetradecylthiopropionic acid treatment was the development of fatty liver. The activity of CTP:phosphocholine cytidylyltransferase and the incorporation of [3H]choline into PC was reduced compared to 3‐thiadicarboxylic acid treatment. Although the rate of methylation of PE seemed to be increased at an elevated AdoMet/AdoHcy ratio, this resulted in only minor changes in the hepatic PC and PE levels, and the PC/PE ratio remained unchanged. Furthermore, the hepatic levels of choline and phosphocholine were reduced in these rats. The activities of the two enzymes competing for choline in the liver, choline kinase and choline dehydrogenase were changed in opposite directions, with the activity of choline kinase increasing approximately 1.5‐fold. In addition, it was found that the level of homocysteine was elevated in the liver of tetradecylthiopropionic acid‐treated rats. The possibility is discussed that this reflects a reduced flux of choline through the oxidative pathway in the liver. In tetradecylthiopropionic acid‐treated rats, there seemed to be a coordinated regulation of the two pathways for PC biosynthesis, with an increase in the methylation of PE to PC and a reduced synthesisvia the CDPcholine pathway. The increase in PC observed in rats treated with 3‐thiadicarboxylic acid and tetradecylthioacetic acid suggests that increased PC synthesis is linked to peroxisome proliferation.
Distribution of ubiquinone and ubiquinol homologues in rat tissues and subcellular fractions
Authors: Takahashi Takayuki , Okamoto Tadashi , Mori Koichi , Sayo Hiroteru , Kishi Takeo 
Published: November 2006

AbstractThe oxidized (UQox) and reduced (UQred) forms of ubiquinone (UQ) homologues in rat tissues and subcellular fractions were analyzed to elucidate their distribution and physiological role. UQ‐9 and UQ‐10 were detected in all tissues studied, and UQ‐9 was the predominant homologue. The total amount of UQox‐10 and UQred‐10 was 20–50% that of UQox‐9 and UQred‐9. The levels of these homologues were highest in heart with lesser amounts occurring in kidney, liver and other organs. In liver and blood plasma, the UQred homologue amounted to 70–80% of the total UQ (UQox+UQred=t‐UQ). UQred was less than 30% of t‐UQ in other tissues and blood cells. t‐UQ was much higher in leukocytes and platelets in blood than in erythrocytes. In erythrocytes, t‐UQ was exclusively located in the cell membranes. UQox and UQred were also found in all subcellular fractions isolated from liver and kidney in about the same ratio as UQred/t‐UQ was present in the whole organ. The levels of UQox and UQred per mg protein in subcellular fractions from liver were highest in mitochondria, with lesser amounts present in plasma membranes, lysosomes, Golgi complex, nuclei, microsomes and cytosol. In the mitochondria, the outer membranes were richer in t‐UQ than the inner membranes. In the Golgi complex, the light and intermediate fractions were rich in t‐UQ when compared to the heavy fraction. The possible physiological role of UQox and UQred in tissues and subcellular fractions is discussed.
Effect of dietary α‐linolenic acid and its ratio to linoleic acid on platelet and plasma fatty acids and thrombogenesis
Authors: Chan Joanna K. , McDonald Bruce E. , Gerrard Jon M. , Bruce Vivian M. , Weaver Bonnie J. , Holub Bruce J. 
Published: November 2006

AbstractThe effect of dietary α‐linolenic acid (18∶3n−3) and its ratio to linoleic acid (18∶2n−6) on platelet and plasma phospholipid (PL) fatty acid patterns and prostanoid production were studied in normolipidemic men. The study consisted of two 42‐d phases. Each was divided into a 6‐d pre‐experimental period, during which a mixed fat diet was fed, and two 18‐d experimental periods, during which a mixture of sunflower and olive oil [low 18∶3n−3 content, high 18∶2/18∶3 ratio (LO‐HI diet)], soybean oil (intermediate 18∶3n−3 content, intermediate 18∶2/18∶3 ratio), canola oil (intermediate 18∶3n−3 content, low 18∶2/18∶3 ratio) and a mixture of sunflower, olive and flax oil [high 18∶3n−3 content, low 18∶2/18∶3 ratio (HI‐LO diet)] provided 77% of the fat (26% of the energy) in the diet. The 18∶3n−3 content and the 18∶2/18∶3 ratio of the experimental diets were: 0.8%, 27.4; 6.5%, 6.9; 6.6%, 3.0; and 13.4%, 2.7, respectively. There were appreciable differences in the fatty acid composition of platelet and plasma PLs. Nevertheless, 18∶1n−9, 18∶2n−6 and 18∶3n−3 levels in PL reflected the fatty acid composition of the diets, although very little 18∶3n−3 was incorporated into PL. Both the level of 18∶3n−3 in the diet and the 18∶2/18∶3 ratio were important in influencing the levels of longer chain n−3 fatty acid, especially 20∶5n−3, in platelet and plasma PL. Production of 6‐keto‐PGF1α was significantly (P<0.05) higher following the HI‐LO diet than the LO‐HI diet although dietary fat source had no effect on bleeding time or thromboxane B2 production. The present study showed that both the level of 18∶3n−3 in the diet and its ratio to 18∶2n−6 were important in influencing long‐chain n−3 fatty acid levels in platelet and plasma PL and that prostanoid production coincided with the diet‐induced differences in PL fatty acid patterns.
Effect of diets rich in linoleic or α‐linolenic acid on phospholipid fatty acid composition and eicosanoid production in atlantic salmon (Salmo salar)
Authors: Gordon Bell J. , Dick James R. , Sargent John R. 
Published: November 2006

AbstractAtlantic salmon post‐smolts were fed diets rich in linoleic acid (sunflower oil, SO), α‐linolenic acid (linseed oil, LO) or long‐chain polyunsaturated fatty acids (fish oil, FO) for a period of 12 wk. In the liver phospholipids of fish fed SO, the levels of 18∶2n−6, 20∶2n−6, 20∶3n−6 and 20∶4n−6 were significantly elevated compared to both other treatment. In choline phospholipids (CPL), ethanolamine phospholipids (EPL) and phosphatidylserine (PS) the levels of 22∶4n−6 and 22∶5n−6 were significantly elevated in fish fed SO. In liver phospholipids from fish fed LO, 18∶2n−6, 20∶2n−6 and 20∶3n−6 were significantly elevated but 20∶4n−6, 22∶4n−6 and 22∶5n−6 were similar or significantly decreased compared to fish fed FO. Liver phospholipids from fish fed LO had increased 18∶3n−3 and 20∶4n−3 compared to both other treatments while EPL and phosphatidylinositol (PI) also had increased 20∶5n−3. In fish fed LO, 22∶6n−3 was significantly reduced in CPL, PS and PI compared to fish fed FO. Broadly similar changes occurred in gill phospholipids. Production of 12‐lipoxygenase metabolites in isolated gill cells stimulated with the Ca2+‐ionophore A23187 were significantly reduced in fish fed either SO or LO compared to those fed FO. However, the ratio 12‐hydroxy‐5,8,10,14‐eicosatetraenoic acid (12‐HETE)/12‐hydroxy‐5,8,10,14,17‐eicosapentaenoic acid (12‐HEPE) was significantly elevated in stimulated gill cells from SO‐fed fish. Although mean values of thromboxane B2 (TXB2) and prostaglandin E2 (PGE2) were increased in fish fed SO, they were not significantly different from those of the other two treatments.
Dietary fish oil inhibits human breast carcinoma growth: A function of increased lipid peroxidation
Authors: Gonzalez Michael J. , Schemmel Rachel A. , Dugan LeRoy , Gray J. Ian , Welsch Clifford W. 
Published: November 2006

AbstractFemale athymic nude mice were implanted subcutaneously with human breast carcinoma MDA‐MB231. Seven to ten days later, the mice were divided into groups and fed a purified diet containing the following types of fat (% of diet):(i) 20% corn oil (CO); (ii) 15% CO:5% fish (menhaden) oil (FO); (iii) 10% CO:10% FO; (iv) 5% CO:15% FO; (v) 1% CO:19% FO; and (vi) 1% CO:19% FO plus antioxidants (α‐tocopherol acetate, 2000 IU/kg diet and tertiary butyl‐hydroquinone, 2% of the total fat). The linoleic acid levels (% of diet) of the groups were 12.0, 9.1, 6.2, 3.3, 0.9 and 0.9%, respectively. After 6–8 wk, the carcinomas were assessed for tumor volume (cm3) and assayed for thiobarbituric acid reactive substances (TBARS). Human breast carcinoma growth was suppressed in mice consuming FO diets without antioxidants as compared to mice fed CO; the greater the amount of dietary FO fed, the greater the carcinoma growth suppression (P<0.05). The addition of antioxidants to the FO diet significantly (P<0.05) reversed the FO‐induced carcinoma growth suppression. Concentrations of TBARS in the human breast carcinomas were increased in all the FO (without antioxidants) fed mice, compared to mice fed CO; the level of increase in TBARS was directly related to the increase in the level of FO fed (P<0.05). The addition of antioxidants to the FO diet significantly (P<0.05) reduced the concentration of TBARS in the breast carcinomas. Thus, these results provide evidence that dietary FO can significantly suppress growth of human breast carcinoma MDA‐MB231, even in the presence of substantial amounts of linoleic acid (3.3–9.1%). The inhibitory effect of FO on growth of these carcinomas was associated with an increased concentration of TBARS in the tumor tissue. In conclusion, dietary FO induced suppression of human breast carcinoma growth is a function, at least in part, of an accumulation of lipid peroxidation products in the tumor tissues.