bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of α‐tocopherol and ascorbyl palmitate on the isomerization and decomposition of methyl linoleate hydroperoxides
Authors: Mäkinen E. Marjukka , Hopia Anu I. 
Published: November 2006

AbstractIn order to study antioxidant action on lipid hydroperoxide decomposition, the effects of α‐tocopherol (TOH) and ascorbyl palmitate on the decomposition rate and reaction sequences of 9‐ and 13‐cis,trans methyl linoleate hydroperoxide (cis,trans ML‐OOH) decomposition in hexadecane were studied at 40°C. Decomposition of cis,trans ML‐OOH as well as the formation and isomeric configuration of methyl linoleate hydroxy and ketodiene compounds were followed by high‐performance liquid chromatographic analysis. TOH effectively inhibited the decomposition of ML‐OOH. The decomposition rate was two times slower at 0.2 mM and more than 10 times slower at 2 and 20 mM of TOH. Ascorbyl palmitale (0.2, 2, and 20 mM) slightly accelerated the decomposition of ML‐OOH. Both compounds had an effect on the reaction sequences of ML‐OOH decomposition. At high levels TOH inhibited the isomerization of cis,trans ML‐OOH to trans,trans ML‐OOH through peroxyl radicals and increased the formation of hydroxy compounds. Further, the majority of the hydroxy and ketodiene compounds formed had a cis,trans configuration, indicating that cis,trans ML‐OOH decomposed through alkoxyl radicals without isomerization. These results suggest that when inhibiting the decomposition of hydroperoxides, TOH can act as a hydrogen atom donor to both peroxyl and alkoxyl radicals. In the presence of ascorbyl palmitate, cis,trans ML‐OOH decomposed rapidly but without isomerization. In contrast to TOH, the majority of hydroxy compounds were cis,trans, but the ketodiene compounds were trans,trans isomers. This indicates that ascorbyl palmitate reduced cis,trans ML‐OOH to the corresponding hydroxy compounds. However, the simultaneous formation of trans,trans ketodiene compounds suggests that ML‐OOH decomposition, similar to the control sample, also occurred in these samples. Thus, under these experimental conditions, the reduction of ML‐OOH to more stable hydroxy compounds did not occur to an extent significant enough to inhibit the radical chain reactions of ML‐OOH decomposition.
Vitamin E and probucol reduce urinary lipophilic aldehydes and renal enlargement in streptozotocin‐induced diabetic rats
Authors: Kim Song‐Suk , Gallaher D. D. , Csallany A. Saari 
Published: November 2006

AbstractDiabetes mellitus is characterized by complications affecting several organs, including the kidney. Lipid peroxidation increases in diabetes and has been implicated in the pathogenesis of diabetic complications. In this study, we examined the ability of two antioxidants, vitamin E and probucol, to reduce lipid peroxidation in vivo and renal hypertrophy, an early stage of diabetic nephropathy, in rats. Animals were divided into four groups: non‐diabetic, diabetic, diabetic treated with vitamin E, and diabetic treated with probucol. Animals were given antioxidants by intraperitoneal injection after induction of diabetes by streptozotocin injection. After 7 wk, lipid peroxidation in vivo was measured by analyzing urinary excretion of lipophilic aldehydes and related carbonyl compounds (LACC) as 2,4‐dinitrophenylhydrazones by high‐performance liquid chromatography. A number of urinary lipophilic nonpolar and polar aldehydes and related carbonyl compounds were identified, almost all of which increased in diabetes. Antioxidant treatment resulted in significantly decreased excretion of urinary LACC excretion. Antioxidant treatment of diabetic rats reduced renal hypertrophy. There was a high correlation between kidney weight and urinary LACC. Since LACC are accepted markers of lipid peroxidation, these results indicate that antioxidants can reduce the elevated lipid peroxidation of diabetes and may slow the onset of diabetic nephropathy.
The effect of γ‐interferon to inhibit macrophage‐high density lipoprotein interactions is reversed by Δ12,14‐prostaglandin J2J2
Authors: Zuckerman Steven H. , Panousis Constantinos , Mizrahi Jacques , Evans Glenn 
Published: November 2006

AbstractMacrophage activation has been recognized as playing a central role in chronic inflammatory diseases in general and more specifically, in the vascular wall during the progression of atherosclerotic lesions. Macrophage‐activating factors present within the atherosclerotic lesion include the colony‐stimulating factors and gamma interferon (IFNγ). In the present study, the effects of IFNγ on macrophage binding and uptake of fluorochrome‐labeled high density lipoprotein (HDL) were investigated by flow cytometry and by measuring the amount of the type B scavenger receptors CD36 and scavenger receptor type B (SR‐BI) by Northern blot analysis. IFNγ‐, but not granulocyte macrophage colony‐stimulating factor (GM‐CSF)‐treated murine peritoneal macrophages displayed a two‐ to threefold decrease in Dil‐labeled HDI uptake. This effect was observed in the absence of a comparable decrease in SR‐BI meassage and protein or CD36 message. This decrease in both HDL binding and uptake was reversed by the peroxisome proliferator‐activated receptor gamma (PPARγ) agonist, Δ12,14‐prostaglandin J2 (15d‐PGJ2), which also inhibited the IFNγ inductin of the β2 integrin CD1 1a. Furthermore, 15d‐PGJ2 increased the expression of SR‐BI and CD36 message and SR‐BI protein which was reflected in an increase in HDL binding and uptake. These results suggest a role for PPARγ agonists in modulating the IFNγ‐mediated macrophage effector functions relevant to atherosclerotic disease progression.
Fatty acid analysis of blood plasma of patients with alzheimer's disease, other types of dementia, and cognitive impairment
Authors: Conquer Julie A. , Tierney Mary C. , Zecevic Julie , Bettger William J. , Fisher Rory H. 
Published: November 2006

AbstractFatty acid differences, including docosahexaenoic acid (DHA; 22:6n‐3) have been shown in the brains of Alzheimer's patients (AD) as compared with normal age‐matched individuals. Furthermore, low serum DHA is a significant risk factor for the development of AD. The relative concentration of DHA and other fatty acids, however, in the plasma of AD patients compared with patients with other kinds of dementias (other dementias; OD), patients who are cognitively impaired but nondemented (CIND), or normal patients is not known. In this study we analyzed the total phospholipid, phosphatidylcholine (PC), phosphatidylethanolamine (PE), and lysophosphatidylcholine (lysoPC) fractions of plasma from patients diagnosed with AD, OD, or CIND and compared them with a group of elderly control subjects with normal cognitive functioning. Plasma phospholipid and PC levels of 20:5n‐3, DHA, total n‐3 fatty acids, and the n‐3/n‐6 ratio were lower in the AD, OD, and CIND groups. Plasma phospholipid 24:0 was lower in the AD, OD, and CIND groups as compared with the group of control patients, and total n‐6 fatty acid levels were higher in the AD and CIND groups only. In the plasma PE fraction, levels of 20:5n‐3, DHA, and the total n‐3 fatty acid levels were significantly lower in the AD, OD, and CIND groups. DHA levels were lower in the lysoPC fraction of CIND individuals only. There were no other differences in the fatty acid compositions of the different phospholipid fractions. Therefore, in AD, OD, and CIND individuals, low levels of n‐3 fatty acids in the plasma may be a risk factor for cognitive impairment and/or dementia. Interestingly, a decreased level of plasma DHA was not limited to the AD patients but appears to be common in cognitive impairment with aging.
In vivo evaluation of the effects of continuous exercise on skeletal muscle triglycerides in trained humans
Authors: Rico‐Sanz Jesus , Moosavi Marjan , Louise Thomas E. , McCarthy John , Coutts Glyn A. , Saeed Nadeem , Bell Jimmy D. 
Published: November 2006

AbstractMagnetic resonance spectroscopy (1H MRS) and imaging (MRI) were used to investigate the effects of a bout of moderate prolonged exercise on intra (IMCL)‐ and extramyocellular lipid (EMCL) utilization in the soleus, tibialis anterior, and gastrocnemius muscles of five trained human subjects. MRI and 1H MRS measurements were obtained before and after a 90 min run on a calibrated treadmill at a velocity corresponding to 64±1.5% of each subjects' maximal rate of oxygen consumption. There were significant decreases in IMCL following exercise in the tibialis (pre: 22.37±4.33 vs. post: 15.16±3.25 mmol/kg dry wt; P<0.01) and soleus (pre: 36.93±1.45 vs. post: 29.85 ±2.44 mmol/kg dry wt; P<0.01) muscles. There was also a decrease in the gastrocnemius muscle, although this did not reach the level of significance (pre: 33.78±5.35 vs. post: 28.48±5.44 mmol/kg dry weight; P<0.10). No significant changes were observed in EMCL or subcutaneous fat. In conclusion, this study showed that IMCL were significantly utilized in the tibialis and soleus muscles of aerobically endurance‐trained humans. The absence of significant utilization of IMCL in the gastrocnemius may reflect differences in fiber type and/or intensity of contraction for each muscle group.
Hepatic microsomal and peroxisomal docosahexaenoate biosynthesis during piglet development
Authors: Li Zhiying , Kaplan Murray L. , Hachey David L. 
Published: November 2006

AbstractThe roles of peroxisomes and microsomes on the biosynthetic pathway for docosahexaenoic acid (DHA) from α‐linolenic acid (ALA) were investigated. Microsomes and peroxisomes were prepared from livers of fetal and neonatal piglets by a combination of differential and gradient layer centrifugation. Microsomes, peroxisomes, and combined cell fractions were incubated with [13C‐U]18∶3n−3. The [M] and [M+18] isotopomers of the fatty acids in the long‐chain polyunsaturated fatty acid (LCPUFA) n−3 pathway were detected by gas chromatography‐mass spectrometry. The quantity of each fatty acid was determined by gas chromatography, and synthesis of each fatty acid was calculated for a 30‐min period. Synthesis of DHA was not detected in combined fetal liver fractions. The data suggest that DHA in the fetus is probably supplied from maternal sources through the placenta. In either singly incubated microsomal or peroxisomal preparations from neonatal livers, no DHA synthesis was detected. After combination of the microsomal and peroxisomal fractions, DHA synthesis was evident and increased rapidly between birth and 2 wk of age. This is the first demonstration of the entire biosynthetic LCPUFA n−3 pathway in subcellular organelles starting from isotopically labeled ALA to the final product, DHA, with all the intermediates present and isotopically labeled. The primary importance of the data is that it unequivocally demonstrates that peroxisomes are required for biosynthesis of DHA from ALA.
Dietary cholesterol induces changes in molecular species of hepatic microsomal phosphatidylcholine
Authors: Bernasconi Ana M. , Garda Horacio A. , Brenner Rodolfo R. 
Published: November 2006

AbstractAfter 21 days on a diet containing 1g% cholesterol and 0.5g% cholic acid, rats had an increased content of cholesterol in liver microsomal lipids. In liver, both cholesterol content and δ9 desaturase activity increased, whereas δ6 and δ5 desaturase activities decreased. These changes correlated with increases in oleic, palmitoleic, and linoleic acids and decreases in arachidonic and docosahexenoic acids in total microsomal lipids. Similar fatty acid changes were found in phosphatidylcholine (PC), the principal lipid of the microsomal membrane. In PC the predominant molecular fatty acid species (67% of the total) in the control rats were 18:0/20:4, 16:0/20:4, and 16:0/18:2; and they mainly determined the contribution of PC to the biophysical and biochemical properties of the phospholipid bilayer. The cholesterol diet decreased specifically the 18:0/20:4 species, and to a lesser extent, 16:0/20:4 and 18:0/22:6. The 18:1‐containing species, especially 18:1/18:2 and less so 16:0/18:1 and 18:1/20:4, were increased. A new 18:1/18:1 species appeared. The independent effects of the presence of cholesterol and change of the fatty acid composition of the phospholipid bilayer of liver microsomes on the packing were studied by fluorescence methods using 6‐lauroyl‐2,4‐dimethylaminonaphthalene, 1,6‐diphenyl‐1,3,5‐hexatriene and 1‐(4‐trimethylammonium phenyl)‐6‐phenyl‐1,3,5‐hexatriene, which test different parameters and depths of the bilayer. Data showed that the increase of cholesterol in the membrane, and not the change of the fatty acid composition of phospholipids, was the main determinant of the increased bulk packing of the bilayer. The increase of fluid oleic‐ and linoleic‐containing species almost compensated for the drop in 20:4‐ and 22:6‐containing molecules. But the most important effect was that the general drop in essential n‐6 and n‐3 polyunsaturated fatty acids meant that this endogenous source for the needs of the animal decreased.
Effect of medium‐chain fatty acid positional distribution in dietary triacylglycerol on lymphatic lipid transport and chylomicron composition in rats
Authors: Carvajal Octavio , Nakayama Masahiro , Kishi Taiji , Sato Masao , Ikeda Ikuo , Sugano Michihiro , Imaizumi Katsumi 
Published: November 2006

AbstractThe present study was carried out to examine if the positional distribution of medium‐chain fatty acid (MCF) in dietary synthetic fat influences lymphatic transport of dietary fat and the chemical composition of chylomicrons in rats with permanent cannulation of thoracic duct. Four types of synthetic triacylglycerol were prepared: (i) sn‐1(3) MCF‐sn 2 linoleic acid, (ii) interesterified sn‐1(3) MCF‐sn 2 linoleic acid, (iii) sn‐2 MCF‐sn‐1(3) linoleic acid, and (iv) interesterified sn‐2 MCF‐sn‐1(3) linoleic acid. A purified diet composed of equal amounts of the synthetic fat and cocoa butter was given to rats with permanent lymph duct cannulation. The positional distribution of MCF in the dietary fat had no significant effect on the lymph flow, triacylglycerol output, phospholipid output, lipid composition of chylomicrons, or the particle size. The positional distribution of MCF in the synthetic triacylglycerol was maintained in the chylomicron triacylglycerol. These results showed that MCF in the dietary triacylglycerol is transported into lymphatics and the positional distribution is well preserved in chylomicron triacylglycerol.
Kinetics of 2‐monoacylglycerol acyl migration in model chylomicra
Authors: Lyubachevskaya Galina , Boyle‐Roden Elizabeth 
Published: November 2006

AbstractIn the metabolism of triacylglycerol (TG)‐rich lipoproteins, 2‐monoacylglycerols (2‐MG) are produced by lipoprotein lipase (LPL) hydrolysis of TG. The metabolic fate of 2‐MG is not known with certainty. 2‐MG that accumulate on the chylomicra surface have been proposed to isomerize spontaneously to 1(3)‐MG, which are then hydrolyzed by LPL to free fatty acids and glycerol. In this study the rate and the effect of acyl chain saturation on the spontaneous acyl migration of 2‐MG in in vitro model chylomicra emulsions were determined. After 1 h of incubation at 37°C, less than 20% of 2‐monoolein (2‐MO) or 2‐monopalmitin (2‐MP) spontaneously isomerized to 1(3)‐MO or 1(3)‐MP, respectively. Accordingly, it was concluded that spontaneous isomerization of 2‐MG is not the major mechanism for 2‐MG metabolism post‐TG hydrolysis in chylomicra. Isomerization rates, expressed as decrease in percentage of 2‐MG remaining per hour, were −5.12 and −5.86 in water, and −0.43 and −0.41 in hexane for 2‐MO and 2‐MP, respectively. There was no significant difference between the isomerization rates of 2‐MO and 2‐MP. Thus, in the present study, saturation of the MG acyl chain did not influence spontaneous acyl migration in either water or hexane, but isomerization of 2‐MG was faster in water than in hexane.
Unusual lipid composition of a Bacillus sp. Isolated from Lake Pomorie in Bulgaria
Authors: Carballeira Nstor M. , Guzmn Aikomari , Nechev Jordan T. , Lahtchev Kantcho , Ivanova Albena , Stefanov Kamen 
Published: November 2006

AbstractThe lipid composition of a Bacillus sp., isolated from Lake Pomorie in Bulgaria, was unusual and consisted of 26 different fatty acids between C12 and C26, with anteiso C15−C17 saturated fatty acids predominating. The furan fatty acid, 10,13‐epoxy‐11‐methyloctadeca‐10,12‐dienoic acid, was also identified, a new finding for this genus. The hydrocarbons consisted of 30 different monounsaturated hydrocarbons, between C25 and C30, with the iso‐iso, iso‐anteiso, anteiso‐anteiso, iso‐normal, and anteiso‐normal methyl branching for odd‐numbered chains, and the iso‐iso, iso‐anteiso, iso‐normal, and anteiso‐normal methyl branching for even‐numbered chains. The double bond positions in these hydrocarbons were determined by dimethyl disulfide derivatization followed by GC‐MS, and the double‐bond cis configuration was confirmed by infrared spectroscopy. Some previously unknown hydrocarbons in bacteria, such as (Z)‐3,21‐dimethyl‐9‐tricosene, (Z)‐3,21‐dimethyl‐10‐tricosene, (Z)‐2,24‐dimethyl‐11‐pentacosene, and (Z)‐2,25‐dimethyl‐13‐hexacosene were identified. Sterols were detected and were based on the sitosterol nucleus.
Lipid class composition of the protozoan Perkinsus marinus, an oyster parasite, and its metabolism of a fluorescent phosphatidylcholine analog
Authors: Soudant P. , Chu F.‐L. E. , Marty Y. 
Published: November 2006

AbstractPerkinsus marinus is one of two important protozoan parasites of the eastern oyster, Crassostrea virginica. The other is Haplosporidium nelsoni. Lipids extracted from 7‐d‐old in vitro cultured P. marinus meronts, incubated with fluorescent‐labeled phosphatidylcholine (FL PC) and nonincubated P. marinus meronts, were analyzed by a high‐performance liquid chromatography (HPLC) system equipped with a diol phase column, in combination with thin‐layer chromatography coupled with a flameionization detector (TLC/FID), and high‐performance thin‐layer chromatography (HPTLC). Various polar and neutral lipid classes were separated by HPLC using a two‐gradient solvent system. Five polar lipid classes—phosphatidylcholine (PC), phosphatidylethanolamine (PE), cardiolipin (CL), sphingomyelin (SM), and phosphatidylserine (PS)—were identified from P. marinus extracts. Four neutral lipid classes—triacylglycerol (TAG), steryl ester (SE), cholesterol (CHO), and fatty alcohol—were distinguished. TLC/FID analysis of meront lipids showed that the weight percentages of PC, PE, CL, SM, PS/PI, TAG, SE, and CHO were 21, 10.7, 4, 2.3, 4.3, 48.7, 7.8, and 1.2%, respectively. HPLC and HPTLC analyses revealed the presence of two SM and PS isomers in P. marinus extracts. Perkinsus marinus effectively incorporated FL PC acquired from the medium and metabolized it to various components (i.e., free fatty acid, monoacylglycerol, diacylglycerol, TAG, PE, and CL). Uptake and interconversion of FL PC in P. marinus meronts increased with time. After 48 h the total uptake of fluorescence (FL) was 28.9% of the FL PC added to the medium, and 43% of the incorporated FL resided in TAG.
Analysis of the addition products of α‐tocopherol with phosphatidylcholine‐peroxyl radicals by high‐performance liquid chromatography with chemiluminescent detection
Authors: Yamauchi Ryo , Hara Yuji , Murase Hironobu , Kato Koji 
Published: November 2006

AbstractA chemiluminescence‐based high‐performance liquid chromatographic method was developed for the analysis of the addition products of α‐tocopherol with phosphatidylcholine‐peroxyl radicals (TOO‐PC). The TOO‐PC eluted from a reversed‐phase column was reacted with a chemiluminescent reagent consisting of a Cypridina luciferin analog and a lipid‐soluble iron chelate in acidic methanol at 50°C, and the generated chemiluminescence was monitored. The detection limit for TOO‐PC by this method was about 1 pmol. This method was applied to the detection of TOO‐PC in the peroxidized membranes prepared from rabbit erythrocyte ghosts. When the erythrocyte ghosts were peroxidized by the addition of a water‐soluble free radical initiator, a peak corresponding to TOO‐PC was detected on the chromatogram with chemiluminescent detection. The amount of TOO‐PC in the erythrocyte membranes increased with the depletion of endogenous α‐tocopherol. The results indicate that this method proved useful for the detection of the TOO‐PC formed by the peroxyl‐radical scavenging reactions of α‐tocopherol in biological systems.
Fatty acid‐specific, regiospecific, and stereospecific hydroxylation by cytochrome P450 (CYP152B1) from Sphingomonas paucimobilis: Substrate structure required for α‐hydroxylation
Authors: Matsunaga Isamu , Sumimoto Tatsuo , Ueda Atsuo , Kusunose Emi , Ichihara Kosuke 
Published: November 2006

AbstractFatty acid α‐hydroxylase from Sphingomonas paucimobilis is an unusual cytochrome P450 enzyme that hydroxylates the α‐carbon of fatty acids in the presence of H2O2. Herein, we describe our investigation concerning the utilization of various substrates and the optical configuration of the α‐hydroxyl product using a recombinant form of this enzyme. This enzyme can metabolize saturated fatty acids with carbon chain lengths of more than 10. The Km value for pentadecanoic acid (C15) was the smallest among the saturated fatty acids tested (C10–C18) and that for myristic acid (C14) showed similar enzyme kinetics to those seen for C15. As shorter or longer carbon chain lengths were used, Km values increased. The turnover numbers for fatty acids with carbon chain lengths of more than 11 were of the same order of magnitude (103 min−1), but the turnover number for undecanoic acid (C11) was less. Dicarboxylic fatty acids and methyl myristate were not metabolized, but monomethyl hexadecanedioate and ω‐hydroxypalmitic acid were metabolized, though with lower turnover values. Arachidonic acid was a good substrate, comparable to C14 or C15. The metabolite of arachidonic acid was only α‐hydroxyarachidonic acid. Alkanes, fatty alcohols, and fatty aldehydes were not utilized as substrates. Analysis of the optical configurations of the α‐hydroxylated products demonstrated that the products were S‐enantiomers (more than 98% enantiomerically pure). These results suggested that this P450 enzyme is strictly responsible for fatty acids and catalyzes highly stereo‐ and regioselective hydroxylation, where structure of ω‐carbon and carboxyl carbon as well as carbon chain length of fatty acids are important for substrate‐enzyme interaction.