bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluating acid and base catalysts in the methylation of milk and rumen fatty acids with special emphasis on conjugated dienes and total trans fatty acids
Authors: Kramer John K. G. , Fellner Vivek , Dugan Michael E. R. , Sauer Frank D. , Mossoba Magdi M. , Yurawecz Martin P. 
Published: November 2006

AbstractMilk analysis is receiving increased attention. Milk contains conjugated octadecadienoic acids (18∶2) purported to be anticarcinogenic, low levels of essential fatty acids, and trans fatty acids that increase when essential fatty acids are increased in dairy rations. Milk and rumen fatty acid methyl esters (FAME) were prepared using several acid‐(HCl, BF3, acetyl chloride, H2SO4) or base‐catalysts (NaOCH3, tetramethylguanidine, diazomethane), or combinations thereof. All acid‐catalyzed procedures resulted in decreased cis/trans (Δ9c, 11t‐18∶2) and increased trans/trans (Δ9t, 11t‐18∶2) conjugated dienes and the production of allylic methoxy artifacts. The methoxy artifacts were identified by gas‐liquid chromatography (GLC)‐mass spectroscopy. The base‐catalyzed procedures gave no isomerization of conjugated dienes and no methoxy artifacts, but they did not transesterify N‐acyl lipids such as sphingomyelin, and NaOCH3 did not methylate free fatty acids. In addition, reaction with tetramethylguanidine coextracted material with hexane that interfered with the determination of the short‐chain FAME by GLC. Acid‐catalyzed methylation resulted in the loss of about 12% total conjugated dienes, 42% recovery of the Δ9c,11t‐18∶2 isomer, a fourfold increase in Δ9t,11t‐18∶2, and the formation of methoxy artifacts, compared with the base‐catalyzed reactions. Total milk FAME showed significant infrared (IR) absorption due to conjugated dienes at 985 and 948 cm−1. The IR determination of total trans content of milk FAME was not fully satisfactory because the 966 cm−1trans band overlapped with the conjugated diene bands. IR accuracy was limited by the fact that the absorptivity of methyl elaidate, used as calibration standard, was different from those of the other minor trans fatty acids (e.g., dienes) found in milk. In addition, acid‐catalyzed reactions produced interfering material that absorbed extensively in the trans IR region. No single method or combination of methods could adequately prepare FAME from all lipid classes in milk or rumen lipids, and not affect the conjugated dienes. The best compromise for milk fatty acids was obtained with NaOCH3 followed by HCl or BF3, or diazomethane followed by NaOCH3, being aware that sphingomyelins are ignored. For rumen samples, the best method was diazomethane followed by NaOCH3.
Hematological and lipid changes in newborn piglets fed milk‐replacer diets containing erucic acid
Authors: Kramer John K. G. , Sauer Frank D. , Farnworth Edward R. , Stevenson Dan , Rock Gail A. 
Published: November 2006

AbstractCanola oil is not presently permitted in infant formulations in the United States because of lack of information concenring the effects of feeding canola oil to the newborn. We have previously reported a transient decrease in platelet counts and an increase in platelet size in newborn piglets fed canola oil for 4 wk, and have confirmed this in the present study. In canola oil‐fed piglets, changes in platelet size and number were overcome by adding either long‐chain saturated fatty acids from cocoa butter (16:0 and 18:0), or shorter‐chain saturates from coconut oil (12:0 and 14:0). Feeding a high erucic acid rapeseed (HEAR) oil, with 20% 22:1n−9, led to an even greater platelet reduction and increased platelet size throughout the 4‐wk trial. Bleeding times were longer in piglets fed canola oil or HEAR oil compared to sow‐reared and soybean oil‐fed piglets. There were no other diet‐related changes. Diet‐induced platelet changes were not related to platelet lipid class composition, but there were fatty acid changes. The incorporation of 22:1n−9 into platelet phospholipids of piglets fed canola oil was low (0.2–1.2%), and even for the HEAR oil group ranged from only 0.2% in phosphatidylinositol to 2.4% in phosphatidylserine. A much greater change was observed in the concentration of 24:1n−9 and in the 24:1n−9/24:0 ratio in platelet sphingomyelin (SM). The 24:1n−9 increased to 49% in the HEAR oil group compared to about 12% in animals fed the control diets (sow‐reared piglets and soybean oil‐fed group), while the 24:1n−9/24:0 ratio increased from about 1 to 12. Even feeding canola oil, prepared to contain 2% 22:1n−9, led to a marked increase in 24:1n−9 to 29% and had a 24:1n−9/24:0 ratio of 5. The canola oil/cocoa butter group, which also contained 2% 22:1n−9, showed a lower level of 24:1n−9 (20%) and the 24:1n−9/24:0 ratio (3) compared to the canola oil group. The results suggest that the diet‐related platelet changes in newborn piglets may be related to an increase in 24:1n−9 in platelet SM, resulting from chain elongation of 22:1n−9. The inclusion of canola oil as the sole source of fat in the milk‐replacer diets of newborn piglets resulted in significant platelet and lipid changes.
Stereochemistry‐dependent inhibition of RAS farnesylation by farnesyl phosphonic acids
Authors: Hohl Raymond J. , Lewis Kriste A. , Cermak Diana M. , Wiemer David F. 
Published: November 2006

AbstractThis investigation compares the effects of three farnesyl pyrophosphate analogs on selected aspects of isoprenoid metabolism. E,E‐α‐Hydroxyfarnesylphosphonate was prepared by an improved variation on a literature synthesis, which also gave access to the new Z,E‐α‐hydroxyfarnesyl‐ and α‐hydroxygeranylphosphonates. A striking find is that only E,E‐α‐hydroxyfarnesylphosphonate induces alteration of RAS processing in intact human‐derived leukemia cells and inhibits farnesyl protein transferase in enzyme assays, while the Z,E‐α‐farnesyl‐ and geranylphosphonates are inactive. The inhibitory activity of E,E‐α‐hydroxyfarnesylphosphonate is greater in enzyme than intact cell assays. This active compound does not significantly inhibit geranylgeranyl protein transferase I or squalene synthase, nor does it diminish cholesterol synthesis. These results indicate that the length of the terpenoid chain and olefin stereochemistry allow selective inhibition of critical enzymes of terpenoid metabolism. Discrimination was observed between inhibition of farnesyl protein transferase and squalene synthase by E,E‐α‐hydroxyfarnesylphosphonate, even though both enzymes utilize farnesyl pyrophosphate as their natural substrate.
Biosynthesis of triacylglycerols containing ricinoleate in castor microsomes using 1‐acyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine as the substrate of oleoyl‐12‐hydroxylase
Authors: Lin Jiann‐Tsyh , Woodruff Carol L. , Lagouche Olivier J. , McKeon Thomas A. , Stafford Allan E. , Goodrich‐Tanrikulu Marta , Singleton John A. , Haney Carol A. 
Published: November 2006

AbstractWe have examined the biosynthetic pathway of triacylglycerols containing ricinoleate to determine the steps in the pathway that lead to the high levels of ricinoleate incorporation in castor oil. The biosynthetic pathway was studied by analysis of products resulting from castor microsomal incubation of 1‐palmitoyl‐2‐[14C]oleoyl‐sn‐glycero‐3‐phosphocholine, the substrate of oleoyl‐12‐hydroxylase, using high‐performance liquid chromatography, gas chromatography, mass spectrometry, and/or thin‐layer chromatography. In addition to formation of the immediate and major metabolite, 1‐palmitoyl‐2‐[14C]rici‐noleoyl‐sn‐glycero‐3‐phosphocholine, 14C‐labeled 2‐linoleoyl‐phosphatidylcholine (PC), and 14C‐labeled phosphatidylethanolamine were also identified as the metabolites. In addition, the four triacylglycerols that constitute castor oil, triricinolein, 1,2‐diricinoleoyl‐3‐oleoyl‐sn‐glycerol, 1,2‐diricinoleoyl‐3‐linoleoyl‐sn‐glycerol, 1,2‐diricinoleoyl‐3‐linolenoyl‐sn‐glycerol, were also identified as labeled metabolites in the incubation along with labeled fatty acids: ricinoleate, oleate, and linoleate. The conversion of PC to free fatty acids by phospholipase A2 strongly favored ricinoleate among the fatty acids on the sn‐2 position of PC. A major metabolite, 1‐palmitoyl‐2‐oleoyl‐sn‐glycerol, was identified as the phospholipase C hydrolyte of the substrate; however, its conversion to triacylglycerols was blocked. In the separate incubations of 2‐[14C]ricinoleoyl‐PC and [14C]ricinoleate plus CoA, the metabolites were free ricinoleate and the same triacylglycerols that result from incubation with 2‐oleoyl‐PC. Our results demonstrate the proposed pathway: 2‐oleoyl‐PC. Out results demonstrate the proposed pathway: 2‐oleoyl‐PC→2‐ricinoleoyl‐PC→ricinoleate →triacylglycerols. The first two steps as well as the step of diacylglycerol acyltransferase show preference for producing ricinoleate and incorporating it in triacylglycerols over oleate and linoleate. Thus, the productions of these triacylglycerols in this relatively short incubation (30 min), as well as the availability of 2‐oleoyl‐PC in vivo, reflect the in vivo drive to produce triricinolein in castor bean.
Studies of lipase‐catalyzed esterification reactions of some acetylenic fatty acids
Authors: Lie Ken Jie Marcel S. F. , Xun Fu 
Published: November 2006

AbstractEsterification of five positional isomers of acetylenic fatty acids [viz. 9:1(2a), 11:1(10a), 18:1(6a), 18:1(9a) and 22:1(13a)] of different chain lengths with n‐butanol in n‐hexane in the presence of eight different lipases [Lipozyme IM 20 (Rhizomucor miehei), Lipolase 100T (R. miehei), Novozyme 435 (Candida antarctica), PPL (porcine pancreatic lipase), CCL (C. cylindracea), PS‐D (Pseudomonas cepacia), Lipase A‐12 (Aspergillus niger) and Lipase AY‐30 (C. rugosa)] was studied. 2‐Nonynoic acid was not esterified except when catalyzed by the lipase from C. antarctica (Novozyme 435) to give 42% butyl ester after 48 h. The lipases from A. niger (Lipase A‐12) and C. rugosa (Lipase AY‐30) showed poor biocatalytic behavior in the esterification of the acetylenic fatty acids studied. 10‐Undecynoic acid gave the highest conversion rate of esterification with each kind of lipase used. 6‐Octadecynoic acid showed a marked degree of resistance to esterification carried out in the presence of C. cylindracea (CCL), P. cepacia (PS‐D), or porcine pancreatic (PPL) lipase but not significantly in the presence of the lipases of R. miehei (Lipozyme IM 20), R. miehei (Lipolase 100T), or Novozyme 435. 9‐Octadecynoic acid and 13‐docosynoic acid were not discriminated and were readily esterified by the remaining six lipases, but when compared to oleic acid the acetylenic fatty acids were comparatively much slower in conversion to the esters.
Bile acid metabolism in analbuminemic rats
Authors: Kambe Akira , Uchida Kiyohisa , Takase Haruto , Nomura Yasuharu , Adachi Yukihiko 
Published: November 2006

AbstractThe bile acid concentrations in the serum, liver, bile, intestines, and feces of 3‐ and 19‐mon‐old male and female Nagase analbuminemic (NA) rats were compared with those in Sprague‐Dawley (SD) rats. There was no significant difference in the bile acid levels between NA and SD rats. However, increased biosynthesis and pool size of cholic acid (CD) derivatives and decreased levels of chenodeoxycholic acid (CDCA) derivatives (increased CA/CDCA ratio) were detected in male NA rats as compared to SD rats. The CA/CDCA ratio in female NA rats was not different from that in their SD rats in the biliary bile flow, bile acid levels in the small and large intestines, fecal bile acid excretion, bile acid concentration in the portal and systemic circulation, and in the pool size of bile acids. The blood lipid concentrations were significantly higher in the NA rats than in the SD rats. The hepatic levels of lipids were not significantly different between the two rat strains. In conclusion, this study showed that metabolism of bile acids in NA rats is not significantly affected, and that the hypercholesterolemia observed in these strains is not related to abnormalities of bile acid metabolism.
Arachidonic acid supplementation enhances synthesis of eicosanoids without suppressing immune functions in young healthy men
Authors: Kelley Darshan S. , Taylor Peter C. , Nelson Gary J. , Mackey Bruce E. 
Published: November 2006

AbstractThis study was conducted to determine the effects of arachidonic acid (AA) supplementation on human immune response (IR) and on the secretion of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4). Ten healthy men (20–38 yr) participated in the study and lived at the Metabolic Suite of the Western Human Nutrition Research Center. They were fed a basal diet (57, 27, and 16 energy percentage from carbohydrate, fat, and protein, respectively, and AA 200 mg/d) for the first 15 d of the study. Additional AA (1.5 g/d) was added to the diet of six men from day 16 to 65, while the remaining four subjects remained on the basal diet. The diets of the two groups were crossed‐over from day 66 to 115. In vitro indices of IR were examined using blood drawn on days 15, 58, 65, 108, and 115. Influenza antibody titers were determined in the sera prepared from blood drawn on days 92 and 115 (23 d postimmunization). AA supplementation caused significant increases in the in vitro secretion of LTB4, and PGE2, but it did not alter the in vitro secretion of tumor necrosis factor α; interleukins 1β, 2, 6; and the receptor for interleukin 2. Nor did it change the number of circulting lymphocytes bearing markers for specific subsets (B, T, helper, suppressor, natural killer) and the serum antibody titers against influenza vaccine. The opposing effects of PGE2 and LTB4 may have led to the lack of change in immune functions tested.
Effects of highly purified eicosapentaenoic acid and docosahexaenoic acid on fatty acid absorption, incorporation into serum phospholipids and postprandial triglyceridemia
Authors: Hansen John‐Bjarne , Grimsgaard Sameline , Nilsen Hugo , Nordøy Arne , Bønaa Kaare H. 
Published: November 2006

AbstractFourteen healthy volunteers were randomly allocated to receive 4 g highly purified ethyl esters of eicosapentaenoic acid (EPA) (95% pure, n=7) or docosahexaenoic acid (DHA) (90% pure, n=7) daily for 5 wk in supplement to their ordinary diet. The n−3 fatty acids were given with a standard high‐fat meal at the beginning and the end of the supplementation period. EPA and DHA induced a similar incorporation into chylomicrons which peaked 6 h after the meal. The relative uptake of EPA and DHA from the meal was >90% compared with the uptake of oleic acid. During absorption, there was no significant elongation or retroconversion of EPA or DHA in total chylomicron fatty acids. The concentration of EPA decreased by 13% and DHA by 62% (P<0.001) between 6 and 8 h after the meal. During the 5‐wk supplementation period, EPA showed a more rapid and comprehensive increase in serum phospholipids than did DHA. DHA was retroconverted to EPA, whereas EPA was elongated to docosapentaenoic acid (DPA). The postprandial triglyceridemia was suppressed by 19 and 49% after prolonged intake of EPA and DHA, respectively, indicating that prolonged intake of DHA is equivalent to or even more efficient than that of EPA in lowering postprandial triglyceridemia. This study indicates that there are metabolic differences between EPA and DHA which may have implications for the use of n−3 fatty acids in preventive and clinical medicine.
Effect of apolipoprotein E polymorphism on serum lipoprotein response to saturated fatty acids
Authors: Tso Tim K. , Park Sunmin , Tsai Yu‐Hwai , Williams Glenn , Snook Jean T. 
Published: November 2006

AbstractThis report summarizes two studies which investigated the effects of apolipoprotein E (apoE) polymorphism on the serum total cholesterol (TC) and lipoprotein cholesterol responses to 8∶0+10∶0 and 12∶0 diets (Study I) and 14∶0, 16∶0, and 18∶0 diets (Study II). Eighteen healthy premenopausal women (3 apoE 3/2, 12 apoE 3/3, 3 apoE 4/3) in study I and another 18 healthy premenopausal women (4 apoE 3/2, 10 apoE 3/3, 3 apoE 4/3, 1 apoE 4/2) in study II consumed a baseline diet providing 40 en% total fat, 11 en % 18∶2, 15 en% 18∶1, 11.5 en% saturated fat for the first week of each 5‐wk period. The experimental diets for both studies provided 40 3n% total fat, 13–14 en% as one of five test saturated fatty acids (SFA), 14–16 en% 18∶1, and 3–4 en% 18∶2. Analysis by apoE phenotypes showed that both the 8∶0+10∶0 diet and the 12∶0 diet in Study Linduced significant increases in serum TC in subjects with different apoE phenotypes with the exception of apoE 3/2 in the medium‐chain triglyceride group. In contrast, in Study II, individuals with apoE 4/3 consuming the 14∶0 diet showed significant increases in serum TC, high density lipoprotein‐cholesterol (HDL‐C), and HDL2‐C, but the same subjects consuming the 16∶0 diet showed significant increases in serum TC and low density lipoprotein‐cholesterol. The findings from both studies indicated serum lipoprotein responses to SFA were different and the variation of responsiveness may be regulated, at least in part, by apoE polymorphism, especially when 14∶0, 16∶0, or 18∶0 was consumed.
Changes in cultured arterial smooth muscle cells isolated from chicks upon cholesterol feeding
Authors: Carazo Angel , Alejandre M. José , Diaz Ramón , Ríos Antonio , Castillo Mercedes , Linares Ana 
Published: November 2006

AbstractWe have developed cultures of smooth muscle cells (SMC) isolated from arterial hypercholesterolemic chicks (cholesterol‐SMC). These cultures are suitable for the study at the molecular level of the changes in arterial SMC induced by a cholesterol diet. By using a strong dose of cholesterol (5%) for 10 d, we obtained very proliferative SMC which became foam cells after 30 d in culture. On the other hand, SMC cultures isolated from control‐fed chicks has a lower growth rate than the SMC ones under the same culture conditions. DNA synthesis was fourfold greater in cholesterol‐SMC than in control‐SMC cultures. Intracellular cholesterol concentrations were the same in both cholesterol and control SMC during the first 14 d of culture but afterward increased in differing ways: after 20 d of culture the cholesterol‐SMC increased their cholesterol content to double the control. We give here the results obtained from transmission electron microscopy, lipid analysis, proliferation studies, DNA, RNA and protein synthesis, and then discuss their implications.
Silver‐ion high‐performance liquid chromatographic separation and identification of conjugated linoleic acid isomers
Authors: Sehat Najibullah , Yurawecz Martin P. , Roach John A. G. , Mossoba Magdi M. , Kramer John K. G. , Ku Youh 
Published: November 2006

AbstractThis is the first report of the application of silverion impregnated high‐performance liquid chromatography (Ag+‐HPLC) to the separation of complex mixtures of conjugated linolenic acid (CLA) isomers present in commercial CLA sources and foods and in biological specimens. This method showed a clear separation of CLA isomers into three groups related to their trans,trans, cis,trans or trans,cis, and cis,cis configuration of the conjugated double‐bound system. In addition, this method separated within each geometrical isomeric group. Following Ag+‐HPLC isolation, gas chromatography (GC)‐electron impact mass spectrometry, and GC‐direct deposition‐Fourier transformed infrared spectroscopy were used to confirm the identity of two major positional isomers in the cis/trans region, i.e., Δ8,10‐ and Δ11,13‐octadecadienoic acid, which had not been chromatographically resolved previously, Furthermore, the potential of this method was demonstrated by showing different Ag+‐HPLC profiles exhibiting patterns of isomeric distributions for biological specimens from animals fed a diet containing a commerical CLA preparation, as well as for a commerical cheese product.
Diabetes‐induced and age‐related changes in fatty acid proportions of plasma lipids in rats
Authors: Nishida Shigeru , Kanno Tatsuhiko , Nakagawa Shigeki 
Published: November 2006

AbstractDiabetes‐induced and age‐related proportional changes in plasma fatty acids of triglycerides (TG), phospholipids (PL), and cholesteryl esters (CE) were investigated using streptozotocin‐induced diabetic and control rats. Among n‐6 fatty acids from diabetic rat plasma, increased proportions of 18∶2n‐6 and 20∶3n‐6 in all three lipid classes and of 18∶3n‐6 in PL at 1–3 months old and in TG at 3–5 months old were observed. The proportions of 20∶4n‐6 decreased in both PL and CE, but were unchanged in diabetic TG. Among the n‐3 fatty acids, in the early stage, diabetes caused increases in the proportions of 18∶3n‐3 in PL and CE and of 20∶5n‐3 and 22∶6n‐3 in TG, while 22∶5n‐3 was decreased later in the disease course. These results suggest reduced Δ5‐desaturase activities on 20∶3n‐6 but not on 20∶4n‐3, while Δ6‐desaturase activity on 18∶2n‐6 was essentially unaffected. Furthermore, the reduction in Δ9‐desaturase activity in diabetic rats may well explain the decreases in the proportions of 16∶1n‐7 and 18∶1n‐7. However, the proportion of 18∶1n‐9, another product of Δ9‐desaturase, was significantly increased in CE and PL as compared to the controls. Thus, there was a discrepancy between our results and those of earlier studies with respect to the n‐9, n‐6, and n‐3 fatty acid proportions of plasma lipids in diabetic rats. We also investigated age‐related changes in the proportions of plasma fatty acids. Although rather small, age‐related changes were evident in both diabetic and control rats.
Effect of continuous enteral medium‐chain fatty acid infusion on lipid metabolism in rats
Authors: You Yi Qian , Ling Pei Ra , Qu Zhensheng , Bistrian Bruce R. 
Published: November 2006

AbstractThis study compared (i) the relative effects of long‐chain triglycerides (LCT) and medium‐chain triglycerides (MCT), (ii) the influence of amount of MCT, and (iii) the impact of medium‐chain fatty acid position, on plasma and lymphatic triglycerides and portal vein free fatty acids. The animals were fed approximately at 250 kcal/kg · day for 20h. The lymph from lymphatic duct and blood from portal vein and systemic circulation were collected. The results showed that feeding 100% MCT for 20h was sufficiently long to reduce significantly the level of linoleic acid in portal vein fatty acids and plasma and lymph triglycerides. However, this alteration induced by MCT feeding was partially prevented by adding LCT to the diet. The level of arachidonic acid was significantly reduced in plasma triglycerides by any of the diets containing medium‐chain fatty acids compared to 100% LCT. When feeding MCT only, palmitoleic acid, presumably reflecting de novo lipogenesis, was increased in lymphatic triglycerides and portal vein fatty acids. Total saturated fatty acids as a total percentage of total fatty acids were also significantly increased in plasma and lymphatic triglycerides and portal vein fatty acids. Thus, when linoleic acid is limiting, the conversion of MCT into long‐chain fatty acids by de novo lipogenesis is likely to be an important metabolic route. Providing LCT with MCT or 2‐monodecanoin appears to limit this pathway.