bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous mass spectrometric measurement of prostaglandins E1 (PGE1) and PGE2 with a deuterated internal standard
Authors: Ferretti Aldo , Flanagan Vincent P. 
Published: November 2006

AbstractThe use of (3,3,4,4‐2H4)PGE2 as internal standard for the quantitative measurement of PGE1 by gas chromatography‐mass spectrometry is reported. A method for the simultaneous analysis of PGE1 and PGE2 is also described. The prostaglandins were analyzed by selected ion monitoring as the methyl ester‐trimethylsilyl ether (ME‐TMS) derivatives of PGB1 and PGB2, respectively. In all cases, a linear response over the range 1 to 70 ng (2.8 to 198 pmoles) was demonstrated. The use of this procedure is exemplified by its application to the PG analysis of sheep seminal vesicles.
The composition and metabolism of high density lipoprotein subfractions
Authors: Schaefer Ernst J. , Foster David M. , Jenkins Leslie L. , Lindgren Frank T. , Berman Mones , Levy Robert I. , Brewer H. Bryan 
Published: November 2006

AbstractThe composition and metabolism of high density lipoprotein (HDL) subfractions were investigated in seven nomal individuals. Mean HDL2 (d, 1.063–1.125 g/ml) composition (by weight) was 43% protein, 28% phospholipid, 23% cholesterol, and 6% triglyceride, and mean HDL3 (d, 1.125–1.21 g/ml) composition was 58% protein, 22% phospholipid, 14% cholesterol, and 5% triglyceride. The mean apoA‐I; apoA‐II weight ratio was 4.75 for HDL2 and 3.65 for HDL3.HDL2 protein was proportionally slightly richer in C apolipoproteins and higher molecular weight constituents (including apoE) than HDL3. Kinetic studies utilizing radiolabeled HDLA (d, 1.09–1.21 g/ml), HDL2, and HDL3 demonstrated rapid exchange of apoA‐I and apoA‐II radioactivity among HDL subfractions, similar fractional rates of catabolism of apoA‐I and apoA‐II within HDL, and similar radioactivity decay within HDL subfractions. Mean plasma residence time was 5.74 days for radiolabeled HDL2 and 5.70 days for radiolabeled HDL3. Differences in HDL protein mass among individuals were largely due to alterations in catabolism, and in general both HDL2 and HDL3 were catabolized via a plasma and a nonplasma pathway. Data from simultaneous radiolabeled very low density lipoprotein and HDL studies in 2 individuals are consistent with the concept that apoC‐II and apoC‐III are catabolized at a different rate than are apoA‐I and apoA‐II within the HDL density range.
Cross‐linking of collagen in the presence of oxidizing lipid
Authors: Sundholm F. , Visapää A. , Björksten J. 
Published: November 2006

AbstractGelatin films containing unsaturated lipid have been exposed to ultraviolet and visible irradiation. No sign of paramagnetism could be detected in the films, although the gelatin was undergoing cross‐linking reactions. The addition of nitroxyl‐forming radical scavengers decreased the rate of cross‐linking, as did addition of ascorbic acid to the reacting mixture. Nitroxyls could not be detected in the gels, however. The conclusion is drawn that the main reaction in the cross‐linking reaction of collagen is a condensation of amino groups and extrinsic or intrinsic carbonyl groups. The extrinsic aldehydes are formed in the autoxidation of unsaturated lipid.
Arachidonic acid intestinal absorption: Mechanism of transport and influence of luminal factors on absorption in vitro
Authors: Chow San Laung , Hollander Daniel 
Published: November 2006

AbstractThe mechanism and characteristics of intestinal absorption of arachidonic acid were studied in vitro using everted intestinal sacs of the rat. Arachidonic acid absorption was studied at concentrations of 5 μM to 8.36 mM. The plot of absorption rate vs. concentration fitted best to a rectangular hyperbola at low μM concentrations and to a straight linear relationship in the mM range of concentrations. Metabolic inhibitors and uncouplers did not change absorption in either range of concentrations. The absorption of arachidonic acid increased with thinning of the unstirred water‐layer, decrease in the pH, or the substitution of sodium taurocholate by Pluronic F 68 or Tween 80. Absorption decreased following the equimolar additions of oleic, linoleic, and linolenic acids. Absorption rate did not change when the taurocholate concentration was varied from 5–15 mM or following the additions of butyric or glutamic acids, leucine, lysine, or dextrose. It was concluded that arachidonic acid is absorbed by a concentration‐dependent dual mechanism of transport which is not energy dependent. At the low μM range of concentrations, facilitated diffusion is predominant, while at mM concentrations, simple diffusion is the dominant mechanism of absorption. Changes in the intestinal fluid composition, flow rate, and pH can modify the rate of absorption of arachidonic acid.
The behavior of rat bile phospholipids in the intestine and in incubation media containing pancreatic juice
Authors: Boucrot P. , Reisser D. , Clement J. 
Published: November 2006

AbstractSamples of radioactive bile were collected from rats after intravenous injection of potassium soaps ([9–103H2] or [114C] oleate, [114C] linoleate or [9–103H2] palmitate). These radioactive acids were chosen because it is well established that, in natural phosphatidyl cholines, palmitic acid is located chiefly at the 1 position and linoleic and oleic acids at the 2 position. After incubation of bile with pancreatic juice, the labeling of unchanged biliary phospholipids was higher when native bile was labeled with oleic acid than with palmitic or linoleic acids. These data suggest that monounsaturated molecular species of biliary phospholipids are more resistant than the diunsaturated ones to in vitro hydrolysis by phospholipase A2. Ninety min after introduction of the radioactive bile into the upper part of the rat duodenum, high labeling of luminal phospholipids was observed regardless of the bile sample used, although labeling of free fatty acids was always low. The passage of intact biliary phospholipids through the intestinal epithelium is discussed.
15‐Methyl‐1,2‐hexadecanediol, a major constituent of hamster surface wax
Authors: Schmid Pathica C. , Wedmid Yuri , Schmid Harald H. O. 
Published: November 2006

AbstractLong chain 1,2‐alkanediol diesters comprise about 15–20% of the acetone soluble skin surface wax of golden Syrian hamsters. The constituent 1,2‐alkanediols, obtained through acidic methanolysis, were fractionated by preparative gas liquid chromatography of their isopropylidene derivatives. The major component (57%) was identified by nuclear magnetic resonance and mass spectrometry as 15‐methyl‐1,2‐hexadecanediol.
Fatty acid and molecular species composition of rat brain phosphatidylcholine and‐ethanolamine from birth to weaning
Authors: Crawford C. G. , Wells M. A. 
Published: November 2006

AbstractThe fatty acid composition of diacyl phosphatidylcholine and phosphatidylethanolamine from the brain of rats 3, 6, 9, 12, 15, 18, and 21 days old were determined. In phosphatidylcholine, the relative amounts of stearic and oleic acid increased from 25% to 33% while the relative amounts of myristic, palmitic, and palmitoleic decreased from 65% to 50% during this time period. The same pattern was seen in phosphatidylethanolamine with stearic and oleic increasing from 38% to 49% and the shorter chain acids decreasing from 17% to 13%. The polyunsaturated fatty content of phosphatidylcholine was approximately 10% and increased slightly during the first 3 weeks, while the polyunsaturated content of phosphatidylethanolamine decreased from 44% to 37%. The molecular species composition of phosphatidylcholine and phosphatidylethanolamine was determined in brains of rats 3, 6, and 9 days old. The relative amounts of the molecular species remained nearly constant during this time period with phosphatidylcholine containing 35% saturated, 40% monoenoic, 6% dienoic, 11% tetraenoic, 2% pentaenoic, and 5% hexaenoic. Phosphatidylethanolamine contained 1% saturated, 8% monoenoic, 3% dienoic, 40% tetraenoic, 9% pentaenoic, and 37% hexaenoic species. Analysis of the fatty acid composition of the molecular species reveals that in phosphatidylcholine the polyunsaturated fatty acids 20∶4 and 22∶6 are predominately paired with 16∶0, while in the phosphatidylethanolamine these two unsaturated fatty acids are paired with 18∶0. Furthermore, dipalmitoyl phosphatidylcholine accounts for approximately 25% of the total molecular species of that lipid.
Cardiopathogenicity of soybean oil and tower rapessed oil triglycerides when fed to male rats
Authors: Kramer J. K. G. , Hulan H. W. , Corner A. H. , Thompson B. K. , Holfeld N. , Mills J. H. L. 
Published: November 2006

AbstractThe triglycerides of soybean oil were purified by molecular distillation and those of Tower rapeseed oil by molecular distillation and adsorption chromatography. The original oils and the purified triglycerides were incorporated in semisynthetic diets at 20% by weight and fed for 16 weeks to weanling male Sprague‐Dawley rats to compare the nutritional and pathological effects of the oils and their triglyceride fractions on rats. The study was carried out at two independent laboratories. No significant differences were observed between the results of the two establishments. The incidence of myocardial lesions was significantly higher in rats fed Tower rapeseed oil than in those fed soybean oil. Purification of the triglycerides by molecular distillation and adsorption chromatography appeared to have no major effect on the incidence of myocardial lesions. This supports our previous findings that the cardiopathogenicity of the test oils to rats resides in the triglycerides of these oils.
The role of gastric lipolysis on fat absorption and bile acid metabolism in the rat
Authors: Roy C. C. , Roulet M. , Lefebvre D. , Chartrand L. , Lepage G. , Fournier L. A. 
Published: November 2006

AbstractIn vivo studies were carried out in young Sprague‐Dawley rats to examine the role of gastric lipolysis on fat absorption and bile acid metabolism. When fed by gastric perfusion 5 times (corn oil, 4 g/day) their usual dietary intake of fat, rats deprived of lingual lipase by the creation of an esophageal fistula had a significant degree of fat and bile acid malabsorption as well as a shortened bile acid halflife when compared to animals with a gastrostomy. The % fat absorption, bile acid loss and bile acid pool were normal in 2 groups of esophageal fistula rats fed the same quantity of corn oil or twice (8 g/day) that amount as a fine emulsion. In view of a negligible gastric lipase activity in animals with an esophageal fistula and of decreased hydrolysis of a triglyceride test meal, these data suggest that gastric lipolysis is of physiological importance in situations where lipolytic mechanisms are stressed by a large fat intake. Its principal role is to potentiate intestinal lipolysis by facilitating the emulsification of dietary lipids through its formed products and, therefore, the contact of pancreatic lipase with its substrates.
Synthesis of saturated, unsaturated, spin‐labeled, and fluorescent cholesteryl esters: Acylation of cholesterol using fatty acid anhydride and 4‐pyrrolidinopyridine
Authors: Patel K. M. , Sklar L. A. , Currie R. , Pownall H. J. , Morrisett J. D. , Sparrow J. T. 
Published: November 2006

AbstractA rapid, high yield method for the preparation of cholesteryl esters is described. The method is a modification of the catalytic procedure previously applied to the acylation of sn‐glycero‐3‐phosphoryl‐choline (Patel, K.M., J.D. Morrisett, and J.T. Sparrow, J. Lipid Res., 20:676 (1979). Cholesteryl esters are formed in excellent yield by acylating cholesterol with fatty acid anhydride or fatty acid and dicyclohexylcarbodiimide in methylene chloride containing 4‐pyrrolidinopyridine. The versatility of the method is demonstrated by the preparation of the cholesteryl esters of saturated, unsaturated, spinlabeled, and labile fluorescent fatty acids.
Incorporation of label from [9, 10‐methylene‐14C] sterculic acid in rainbow trout,Salmo gairdneri
Authors: Eisele T. A. , Parker R. S. , Yoss J. K. , Nixon J. E. , Pawlowski N. E. , Sinnhuber R. O. 
Published: November 2006

AbstractThe distribution of radioactivity from sterculic acid, labeled on the 9,10‐methylene carbon of the cyclopropene ring, was investigated in trout,Salmo gairdneri. Fifty percent of the administered dose was excreted in feces and urine by 168 hr, but less than 1% of the dose was expired as carbon dioxide during the same time period. Incorporation of radioactivity into most organs peaked at 119 hr, and the majority of the label in the liver was in the fatty acid portion of the lipid fraction. Total lipid radioactivity in liver was higher in trout conditioned to cyclopropene lipids, and a substantial amount of label was found in phosphatidylcholine and ethanolamine phospholipids as well as neutral lipid. The data demonstrate that rainbow trout readily absorb, transport and incorporate sterculic acid into tissue lipid, including membrane lipid, but cannot oxidize the methylene carbon of the cyclopropene ring to carbon dioxide.
Reproduction and survival of rainbow trout (Salmo gairdneri) fed linolenic acid as the only source of essential fatty acids
Authors: Yu T. C. , Sinnhuber R. O. , Hendricks J. D. 
Published: November 2006

AbstractA semipurified test diet containing 1% linolenate as the sole dietary essential fatty acid was fed to a group of rainbow trout (Salmo gairdneri) for 34 months. The fish matured and the eggs produced were hatched. The second generation fry were fed our laboratory diet for 3 months. The growth of these fry was normal. Histologic examinations revealed no abnormality in liver, heart and kidney tissues of the fry during the three month period.
Argentation chromatography on silver sulfamate‐impregnated silica gel layers
Authors: Ilinov Peter P. 
Published: November 2006

AbstractSilver sulfamate was used in place of silver nitrate as argentation and charring reagent in thin layer chromatography (TLC). This reagent permits thin layer chromatographic separations of fatty acid esters with differing degrees of unsaturation as well as ofcis/trans isomeric fatty acids, and allows for direct charring of fractions. Examples given for separations on silica gel plates impregnated with silver sulfamate include cholesterol esters and fatty acid methyl esters.
Desaturation of positional and geometric isomers of monoenoic fatty acids by microsomal preparations from rat liver
Authors: Pollard Michael R. , Gunstone Frank D. , James Anthony T. , Morris Lindsay J. 
Published: November 2006

AbstractA range ofcis‐ andtrans‐monoenoic fatty acids was tested as substrates for desaturation in microsomal preparations from rat liver.Trans‐monoenoic acids were generally desaturated in the Δ9 position to the same extent as stearic acid. Acids with Δ7‐trans‐ and Δ11‐trans‐olefinic unsaturation produced Δ7‐trans,9‐cis‐ and Δ9‐cis,11‐trans‐conjugated dienoic acids, respectively, but the Δ8‐trans‐ and Δ10‐trans‐monoenoic acids did not give Δ8,9‐ or Δ9,10‐allenes. Of thecis‐monoenoic acids examined, only those with double bonds at or beyond the Δ14 position gave any measurable Δ9 desaturation. When Δ9 desaturation of long chain saturated acids was inhibited by adding sterculic acid, these saturated acids were desaturated at the Δ5 and Δ6 positions. Many of the monoenoic acids tested were also desaturated at the Δ5 and/or Δ6 positions, although the percentage conversions were always low. Δ9‐cis,11‐trans‐, Δ9‐cis,12‐trans‐ and Δ9‐cis,13‐trans‐dienoic acids, produced in situ by Δ9 desaturation of the corresponding monoenoic acids, were extensively desaturated in the Δ6 position. These results are discussed in terms of: (a) the various models proposed to explain the substrate specificities of the desaturases, and (b) the metabolism of unnatural fatty acids ingested from dietary sources.
The fatty acid composition of three unicellular algal species used as food sources for larvae of the American oyster (Crassostrea virginica)
Authors: Chu Fu‐Lin E. , Dupuy John L. 
Published: November 2006

AbstractThe total lipid and fatty acid content of 3 algal species,Pyramimonas virginica, Pseudoisochrysis paradoxa andChlorella sp., which have been successful as food sources for rearing larvae of the American oyster,Crassostrea virginica, was determined. Of the fatty acids of ω6 and ω3 families which have been shown to be essential fatty acids for normal growth in many animals, only the ω6 fatty acids were found to be higher in these 3 species of algae than in the traditional oyster larvae diet which consists of the algaeMonochrysis lutheri andIsochrysis galbana. The major fatty acid constituents of the total lipids of the 3 species were the C12, C14, C16 and C18 saturated fatty acids and the C16 and C18 mono‐ and polyunsaturated acids. These components constituted 70–93% of the total lipid in cultures of all ages. There were modest amounts of C20 and C22 polyunsaturated acids; some of these existed only in trace amounts. InP. virginica andChlorella sp., hexadecanoic acid was dominant (23–39%). The presence of large quantities of tetradecanoic acid (22–26%) and oleic acid (17–21%) was characteristic ofP. paradoxa. Chlorella sp. had the highest proportion of octadecatrienoic acid (18∶3ω3) which accounted for up to 17% of the total lipids. γ‐Linolenic acid (18∶3ω6) was found only inChlorella sp., but in the 5th‐day culture only. The lowest proportion of total polyethylenic acid was inP. paradoxa; however, lipid analyses showed this alga had the most lipid/individual cell. Some variations were observed in the fatty acid composition with age of the culture.
Separation and purification of lecithins by high pressure liquid chromatography
Authors: Porter N. A. , Wolf R. A. , Nixon J. R. 
Published: November 2006

AbstractTen different synthetic lecithins have been analyzed by reverse‐phase high pressure liquid chromatography. An empirical lecithin “carbon number” that depends on the total number of carbons and double bonds in the fatty acyl chains in a useful index in predicting retention volumes of lecithins on a nonpolar octadecyl fatty acid column. Commercial egg lecithin is separated into its components by this technique.
1,25‐dihydroxyvitamin D3 increases the activity of the intestinal phosphatidylcholine deacylation‐reacylation cycle
Authors: O'Doherty P. J. A. 
Published: November 2006

AbstractThe activity of the intestinal phosphatidylcholine deacylation‐reacylation cycle has been found to be stimulated by 1,25‐dihydroxy‐vitamin D3. The stimulation of this cycle thus provides a possible mechanism for the reported retailoring of the fatty acid composition of phosphatidylcholine in intestinal cell membranes by 1,25‐dihydroxy‐vitamin D3 and its analogue, 1α‐hydroxyvitamin D3.
Determination of the absolute configuration at C‐20 and C‐24 of ergosterol in ascomycetes and basidiomycetes by proton magnetic resonance spectroscopy
Authors: Adler John H. , Young Michael , Nes William R. 
Published: November 2006

AbstractSamples of ergosterol isolated fromSaccharomyces cerevisiae, Neurospora crassa, andAgaricus sp., and commercial ergosterol all displayed identical proton magnetic resonance (PMR) spectra at 220 MHz. From the effects produced on the doublet for C‐21 by epimerization at C‐20 and C‐24 in sterols of known configuration, the absolute configurations at these positions in ergosterol were determined. The data demonstrate that ergosterol from both Ascomycetes and Basidiomycetes is the same and that at C‐20 and C‐24, the two H‐atoms are on the α‐side of the asymmetric carbon atoms and that C‐22 istrans‐oriented with respect to C‐13 about the 17(20)‐bond.
Influence of fasting‐refeeding and dietary linoleate on liver glucose‐6‐phosphate dehydrogenase and phospholipid fatty acid composition in rats adapted to a purified diet
Authors: Williams M. A. , Tinoco J. , Ojakian M. A. , Clark L. 
Published: November 2006

AbstractResponses to refeeding after fasting were studied in male rats fed a purified casein‐sucrose diet containing 5% safflower oil. After a 48 hr fast, the rats were fed either the same diet or the same diet minus oil (fat‐free diet). These experiments were designed to distinguish changes due to fasting and refeeding alone without a change of diet from those changes caused by refeeding a diet of different composition. In the first experiment, rats were refed for 3 or 7 days. In rats refed either diet, liver glucose‐6‐phosphate dehydrogenase (G6PD) activity was elevated above refasting levels, but after 7 days, activity in rats refed the 5% safflower oil diet was significantly lower than in those refed the fatfree diet. The amount of liver arachidonate in rats refed the safflower oil diet was the same during refeeding as before fasting. In the second experiment, rats were refed the fat‐free diet for 1, 2, 3, or 7 days. Liver G6PD and fatty acid synthetase were measured, as well as fatty acids in liver total lipids and phospholipids. G6PD activity increased above prefasting levels after one day refeeding and continued to increase, for 7 days. Fatty acid synthetase activity increased for the first 3 days of refeeding, with no additional increase after 7 days. In all rats refed the fat‐free diet, the proportions of arachidonate and linoleate in liver phospholipids diminished with time, and eicosatrienoate appeared. These results show that (a) maintenance of liver phospholipid arachidonate did not prevent increased G6PD activity in early refeeding, but the elevated G6PD activity later declined when phospholipid arachidonate was maintained by feeding a source of linoleate; (b) the metabolic state of fastedrefed rats had not returned to prefasting conditions even after 7 days of refeeding a linoleate‐rich diet to which the rats were adapted before fasting.
Pancreatic and microbial lipases: A comparison of the interaction of pancreatic colipase with lipases of various origins
Authors: Canioni P. , Julien R. , Rathelot J. , Sarda L. 
Published: November 2006

AbstractConjugated bile salts inhibit the hydrolysis of triglycerides (TG) by the lipases fromRhizopus arrhizus andGeotrichum candidum. This occurs for detergent concentrations similar to those which suppress the action of mammalian pancreatic lipases upon the same substrates. However, in opposition with what is observed with the latter enzymes, the activity is not restored by the addition of pancreatic colipase. Both pancreatic andR. arrhizus lipases are inactivated at tributyrin/water interface, but only the first enzyme is protected against this surface denaturation by the pancreatic cofactor. These observations suggest that colipases synthesized in mammalian pancreas display specific interaction towards the lipases made by the same organ.