bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of trans‐monounsaturated alkenyl chains in total plasmalogens (1‐O‐alk‐1′‐enyl‐2‐acyl glycerophospholipids) from sheep heart
Authors: Wolff Robert L. 
Published: November 2006

AbstractIn the present study, we investigated the alkenyl chains from sheep heart plasmalogens (1‐O‐alk‐1′‐enyl‐2‐acyl glycerophospholipids) after their conversion into trimethylene dioxyalkanyl (TMDOA) derivatives. Particular attention was given to monounsaturated alkenyl chains (C18 mainly). For this purpose, a combination of silver ion TLC and GLC on highly polar, very long capillary columns was applied to TMDOA derivatives. Approximately 30 different alkenyl chains could be separated, and the main observation was that the component previously reported as a cis‐9 18∶1 alkenyl chain in plasmalogens embraces in fact a wide range of trans and cis isomers, in amounts equal to 7.9 and 5.6%, respectively, of total alkenyl chains. Concerning the trans‐monoenoate fraction, isomers with their ethylenic bond spanning from Δ6–Δ8 to Δ16 were tentatively identified on the basis of their distribution profile, which was similar to that of trans‐18∶1 acids prepared and isolated from sheep adipose tissue. The main trans‐monoenoic C18 alkenyl chain in sheep heart plasmalogens would thus have its double bond in position 11, which seems logical, as alkenyl chains are derived from the corresponding alcohols, themselves issued from the corresponding FA, and in this particular case, vaccenic (trans‐11 18∶1) acid. cis‐Monoenoic C18 alkenyl chains also appear more complex than realized earlier, showing in particular isomers with their ethylenic bond farther than the Δ9 position, in addition to the main isomer derived from oleic acid. Several trans‐16∶1 alkenyl chains could be observed (totaling ca. 1%), but cis‐16∶1 isomers were present in trace amounts only.
A direct method for regiospecific analysis of TAG using α‐MAG
Authors: Turon F. , Bachain P. , Caro Y. , Pina M. , Graille J. 
Published: November 2006

AbstractAn analytical procedure was developed for regiodistribution analysis of TAG using α‐MAG prepared by an ethyl magnesium bromide deacylation. In the present communication, the deacylation procedure is shown to lead to representative α‐MAG, allowing the composition of the native TAG in the α‐position to be determined directly. The composition in the β‐position can then be estimated from the composition of the α‐MAG and TAG according to the formula, 3×TAG‐2×α‐MAG. The estimates are superior to those obtained using the α,β‐DAG and Brockerhoff calculations as they come closer to the theoretical value and have smaller SD. The present procedure, first demonstrated on a synthetic TAG, was then successfully applied to the analysis of borage oil, milkfat, and tuna oil.
Visual acuity and retinal function in infant monkeys fed long‐chain PUFA
Authors: Jeffrey Brett G. , Mitchell Drake C. , Hibbeln Joseph R. , Gibson Robert A. , Lee Chedester A. , Salem Norman 
Published: November 2006

AbstractPrevious randomized clinical trials suggest that supplementation of the human infant diet with up to 0.35% DHA may benefit visual development. The aim of the current study was to assess the impact of including arachidonic acid (AA) and a higher level of DHA in the postnatal monkey diet on visual development. Infant rhesus monkeys were fed either a control diet (2.0% α‐linolenic acid as the sole n−3 FA) or a supplemented diet (1.0% DHA and 1.0% AA) from birth. Visual evoked potential acuity was measured at 3 mon of age. Rod and cone function were assessed in terms of parameters describing phototransduction. Electroretinogram (ERG) amplitudes and implicit times were recorded over a wide intensity range (−2.2 to 4.0 log scot td‐sec) and assessed in terms of intensity response functions. Plasma DHA and AA were significantly increased (P <0.001) in the diet‐supplemented monkeys compared with the control monkeys. There was an approximately equal effect of diet for the rod phototransduction parameters, sensitivity, and capacitance but in the opposite directions. Diet‐supplemented monkeys had significantly shorter b‐wave implicit times at low retinal illuminances (<−0.6 log scot td‐sec). There were no significant effects of diet for visual acuity or the other 23 ERG parameters measured. The results suggest that supplementation of the infant monkey diet with 1.0% DHA and 1.0% AA neither harms nor provides substantial benefit to the development of visual acuity or retinal function in the first four postnatal months.
Relationship between platelet phospholipid FA and mean platelet volume in healthy men
Authors: Li Duo , Turner Alan , Sinclair Andrew J. 
Published: November 2006

AbstractIncreased mean platelet volume (MPV) has been suggested as an independent risk factor for acute myocardial infarction and the increased reactivity of large platelets. The aim of this study was to investigate the correlation between platelet phospholipid (PL) PUFA composition and MPV in 139 free‐living healthy men ages 20–55 yr (vegans, n=18; ovolacto vegetarians, n=43; modrerate meat‐eaters, n=60; and high meateaters, n=18). Each subject completed a semiquantitative Food Frequency Questionnaire and gave a blood sample. Platelet PL FA composition and MPV were determined by standard methods. MPV was significantly greater in the vegans than in the ovolacto vegetarian, moderate, or high meat‐eater groups (P<0.01). Both vegan and ovolacto vegetarian groups had significantly higher platelet PL 18∶2n−6 and 22∶4n−6, and lower 20∶5n−3 and 22∶6n−3 compared with the moderate and high meat‐eater groups. The vegans demonstrated a significant reduction in 20∶4n−6 and 22∶5n−3 compared with the ovolacto vegetarian, high meat‐eater, and moderate meat‐eater groups. Bivariate analysis results showed that MPV was significanly positively correlated with platelet PL 18∶2n−6 (P=0.048) and negatively correlated with 20∶3n−6 (P=0.02), 20∶5n−3 (P=0.005), and 22∶5n−3 (P<0.0001), respectively. In a multiple linear regression analysis, after controlling for potential confounding factors such as dietary group, age exercise, body mass index, and dietary polyunsaturated and saturated fat, cholesterol, carbohydrate, and fiber intake, the MPV was still strongly negatively correlated with platelet PL 20∶3n−6 (P=0.003) and 22∶5n−3 (P=0.001). The present data suggest that 20∶5n−3 and 20∶3n−6 may play a role in the structural function of the platelet membrane.
Anandamide and other N‐acylethanolamines in human tumors
Authors: Schmid Patricia C. , Wold Lester E. , Krebsbach Randy J. , Berdyshev Evgueni V. , Schmid Harald H. O. 
Published: November 2006

AbstractLong‐chain N‐acylethanolamines (NAE), including the endocannabinoid, anandamide, accumulate in mammalian tissues under a variety of pathological conditions. They have also been shown to inhibit the growth of various cancer cell lines in vitro. Here, we report the presence, in widely differing amounts (3.88–254.46 pmol/μmol lipid P), of NAE and their precursor phospholipids in various human tumors and some adjacent unaffected tissue. Anandamide ranged from 1.5 to 48% of total NAE, and incubation of tissue homogenates suggested possible NAE biosynthesis by both the established transacylation‐phosphodiesterase pathway via N‐acyl PE and by direct N‐acylation of ethanolamine.
Clinical trial results support a preference for using CLA preparations enriched with two isomers rather than four isomers in human studies
Authors: Gaullier Jean‐Michel , Berven Grethe , Blankson Henrietta , Gudmundsen Ola 
Published: November 2006

AbstractCLA mixtures are now commercially available. They differ from each other with respect to their content of CLA isomers and their degree of purification. As a group of natural FA, CLA have been widely assumed to be safe. However, the suspected presence of both impurities and particular isomers might induce undesirable side effects. Despite this potential health risk, only a few CLA preparations have been tested under rigorous conditions for clinical efficacy and safety. Based on the limited results available, it is possible to suggest that preparations enriched in c9,t11 and t10,c12 isomers are preferable for human consumption compared to preparations containing four isomers, in terms both of safety and efficacy.
In vitro desaturation and elongation of rumenic acid by rat liver microsomes
Authors: Berdeaux O. , Gnädig S. , Chardigny J. M. , Loreau O. , Noël J. P. , Sébédio J. ‐L. 
Published: November 2006

AbstractVarious nutritional studies on CLA, a mixture of isomers of linoleic acid, have reported the occurrence of conjugated long‐chain PUFA after feeding experimental animals with rumenic acid, 9c,11t–18∶2, the major CLA isomer, probably as a result of successive desaturation and chain elongation. In the present work, in vitro studies were carried out to obtain information on the conversion of rumenic acid. Experiments were first focused on the in vitro Δ6‐desaturation of rumenic acid, the regulatory step in the biosynthesis of long‐chain n−6 PUFA. The conversion of rumenic acid was compared to that of linoleic acid (9c,12c–18∶2). Isolated rat liver microsomes were incubated with radiolabeled 9c,12c–18∶2 and 9c,11t–18∶2 under desaturation conditions. The data indicated that [1‐14C]9c,11t–18∶2 was a poorer substrate for Δ6‐desaturase than [1‐14C]‐9c,12c–18∶2. Next, in vitro elongation of 6c,9c,11t–18∶3 and 6c,9c,12c–18∶3 (γ‐linolenic acid) was investigated in rat liver microsomes. Under elongation conditions, [1‐14C]6c,9c,11t–18∶3 was 1.5‐fold better converted into [3‐14C]8c,11c,13t–20∶3 than [1‐14C]6c,9c,12c–18∶3 into [3‐14C]8c,11c,14c–20∶3. Finally, in vitro Δ5‐desaturation of 8c,11c,13t–20∶3 compared to 8c,11c,14c–20∶3 was investigated. The conversion level of [1‐14C]8c,11c,13t–20∶3 into [1‐14C]5c,8c,11c,13t–20∶4 was 10 times lower than that of [1‐14C]8c,11c,14c–20∶3 into [1‐14C]5c,8c,11c,14c–20∶4 at low substrate concentrations and 4 times lower at the saturating substrate level, suggesting that conjugated 20∶3 is a poor substrate for the Δ5‐desaturase.
Tuna fishmeal as a source of DHA for n−3 PUFA enrichment of pork, chicken, and eggs
Authors: Howe Peter R. C. , Downing Jeffrey A. , Grenyer Brin F. S. , Grigonis‐Deane Elizabeth M. , Bryden Wayne L. 
Published: November 2006

AbstractEnriching foods with long‐chain n−3 PUFA (LC n−3 PUFA) is an important approach to increasing the dietary intake of these beneficial nutrients. Enrichment of meat and eggs can be achieved by adding flaxseed, fish oil, or fishmeal to pig or poultry feeds. However, utilization of these sources, particularly fishmeal, has been limited by concerns about adverse effects on sensory qualities. In this study, we evaluated the use of PorcOmegaTM (POM), a stabilized tuna fishmeal formulation, as a source of DHA for enrichment of pork and poultry products. Pigs, broilers, and laying hens were fed rations containing varying levels of POM for varying time periods, and its impact on the LC n−3 PUFA content and sensory qualities of cooked meat and eggs was examined. Pork and chicken products, including chops, sausages, and eggs, with substantially increased (up to sevenfold) levels of LC n−3 PUFA (predominantly DHA) were achieved by including up to 10% POM in rations. The increases were retained after cooking. Some sensory deficits were noted when using higher levels of POM (exceeding 15% in meat and 10% in eggs). However, at modest rates of feeding (5–10% POM), palatable meat and eggs were obtained with worthwhile levels of enrichment. The fishmeal feeding strategy used in this study offers a viable means of producing a range of alternative dietary sources of LC n−3 PUFA.
Rapid and improved method for the determination of bile acids in human feces using MS
Authors: Perwaiz Shahid , Mignault Diane , Tuchweber Beatriz , Yousef Ibrahim M. 
Published: November 2006

AbstractA simple method for the determination of bile acids in adult human fecal samples using GC‐MS is described. Bile acids are directly extracted from feces by ethanol (95%) containing 0.1 N NaOH. Extracts are purified by passage through a reversed‐phase C18 silica cartridge and then analyzed by GC‐MS. The present study has shown that lyophilized human feces contain mainly free bile acids, with lithocholic acid (LCA) and deoxycholic acid (DCA) as the major bile acids; however, isomers of LCA and DCA, keto‐bile acids, and cholic acid are also present. Any traces of conjugated bile acids are hydrolyzed before the C18 extraction by deconjugating enzymes, which are present in feces and are activated by the addition of water during the homogenization step. Thus, the analysis of fecal bile acids can be performed without the hydrolysis step in less than 4 h in comparison to traditional techniques, which usually require at least 48 h.
Digestion and assimilation features of dietary DAG in the rat small intestine
Authors: Kondo Hidehiko , Hase Tadashi , Murase Takatoshi , Tokimitsu Ichiro 
Published: November 2006

AbstractSeveral recent studies have demonstrated that dietary DAG oil rich in 1,3‐species suppresses the postprandial increase of serum TAG level and decreases body fat accumulation, compared with TAG oil. To clarify the mechanisms underlying the beneficial effects of DAG, we investigated the metabolic features of DAG in the small intestine with regard to the digestion pathway in the lumen and the TAG‐synthesis pathway in the mucosa. When intraduodenally infused as an emulsion, TAG was digested to 1,2‐DAG, 2‐MAG, and FFA, whereas 1,3‐DAG was digested to 1(3)‐MAG and FFA. When assessed by the incorporation of [1‐14C]linoleic acid in lipids, the mucosal TAG‐synthesis was significantly reduced by DAG infusion compared with TAG infusion. However, the mucosal 1,3‐DAG synthesis was remarkably increased in the DAG‐infused rats. The total amount of mucosal 1,3‐DAG was also increased (4.5‐fold) after DAG infusion compared with that after TAG infusion. Next, we examined the synthesis pathway of 1,3‐DAG. In cultures of the everted intestinal sacs, 1,3‐DAG production required the presence of 1‐MAG, suggesting that the 1,3‐DAG synthesis was due to acylation of 1(3)‐MAG in the DAG‐infused rats. Furthermore, measurements of DAG acyltransferase activity indicated that 1,3‐DAG was little utilized in TAG synthesis. These findings suggest that features of 1,3‐DAG digestion and assimilation in the intestine may be responsible for the reduction of the postprandial serum TAG level by dietary DAG.
Effects of dietary thermoxidized fats on expression and activities of hepatic lipogenic enzymes in rats
Authors: Eder Klaus , Suelzle Andrea , Skufca Peter , Brandsch Corinna , Hirche Frank 
Published: November 2006

AbstractThis study was undertaken to investigate the effect of dietary oxidized fats on the relative mRNA concentrations and the activities of fatty acid synthase (FAS) and glucose‐6‐phosphate dehydrogenase (G6PDH) in the liver of rats treated with vitamin E or selenium. Two experiments with male Sprague‐Dawley rats were carried out. The first experiment included eight groups of rats fed diets with either fresh fat or three different types of oxidized fat, preparated by heating at temperatures of 50, 105, or 190°C, over a period of 6 wk. The diets contained either 25 or 250 mg α‐tocopherol equivalents per kg. The second experiment included four groups of rats fed diets with fresh fat or oxidized fat, heated at a temperature of 55°C, containing either 70 or 570 μg selenium per kg, over a period of 8 wk. Feeding the diets with oxidized fats led to a significant overall reduction of the relative mRNA concentrations and the activities of FAS and G6PDH in both experiments. The effects of the oxidized fats on mRNA concentrations and activities of these enzymes were independent of the dietary concentrations of vitamin E or selenium. Moreover, in both experiments the rats whose diet contained the oxidized fats had significantly lower concentrations of TG in liver, plasma, and VLDL than the rats whose diet contained fresh fat. The study suggests that oxidized fats contain substances that suppress gene expression of lipogenic enzymes in the liver.
Characterization of glycerophosphocholine phosphodiesterase activity and phosphatidylcholine biosynthesis in cultured retinal microcapillary pericytes. Effect of adenosine and endothelin‐1
Authors: Anfuso Carmelina D. , Sipione Simonetta , Lupo Gabriella , Ragusa Nicolò , Alberghina Mario 
Published: November 2006

AbstractIn pericytes from bovine retina, the enzyme glycerophosphocholine phosphodiesterase, catalyzing the hydrolysis of sn‐glycero‐3‐phosphocholine to glycero‐3‐phosphate and choline, has been characterized with respect to pH optimum, metal ion dependence, Km, inhibitors, and subcellular localization. In these cells, the natural substrate sn‐glycero‐3‐phosphocholine was present at relatively high concentration (6.4±1.2 nmol/mg protein), and the EDTA‐sensitive phosphodiesterase activity was also found to be markedly high (9.80±1.5 nmol/min/mg protein) compared to the estimated in liver and brain (1–3 nmol/min/mg protein) or in renal epithelial cell culture (0.27 nmol/min/mg protein). The reaction conditions were in general agreement with those found earlier in brain and other tissues. The majority of the enzyme specific activity was located in the plasma membrane, whereas a minor part was present in the microsomal fraction. The physiological significance of the high catabolic phosphodiesterase activity in these cells may be related to the tranfer, followed by deacylation, of lysophosphatidylcholine from the bloodstream to nervous tissue. In addition, capillary pericytes in culture were able to incorporate 3H‐choline rapidly into choline‐containing soluble phosphorylated intermediates and into phosphatidylcholine. To find a positive and negative effector on phosphatidylcholine formation, adenosine, an important intercellular mediator in the retina in response to alterations in oxygen delivery, and endothelin‐1, a potent paracrine mediator present at the blood‐brain and blood‐retina barrier, were tested. The cells cultured for 1 or 24 h in a medium containing adenosine at concentrations of 10−6 and 10−4 M showed significant reduction in 3H‐choline incorporation compared to control cultures, whereas endothelin‐1, at a concentration of 10 and 100 nM, caused stimulation of phosphatidylcholine biosynthesis. These findings provide evidence that both agonists may modulate phosphatidylcholine metabolism in pericytes.
Photochemical oxidation and autoxidation of chlorophyll phytyl side chain in senescent phytoplanktonic cells: Potential sources of several acyclic isoprenoid compounds in the marine environment
Authors: Rontani Jean‐François , Rabourdin Adélaïde , Marchand Daphné , Aubert Claude 
Published: November 2006

AbstractVisible light‐induced degradation of the chlorophyll phytyl side chain was studied in senescent cells of two phytoplanktonic strains (Skeletonema costatum and Thalassiosira weissflogii). Particular attention was paid to the induction of autoxidation processes on the phytyl chain and its photoproducts by photochemically produced hydroperoxides. The combination of photochemical oxidation and autoxidation reactions resulted in the production of several acyclic isoprenoid compounds that have been unambiguously identified by comparison of their retention times and mass spectra with those of appropriate standards. Various mechanisms are proposed to explain the formation of these oxidation products. These processes appear to be potential sources of numerous oxidized acyclic isoprenoids that previously have been detected in lacustrine and marine environments. Some oxidation products newly described or whose presence in natural samples was never reported in the literature were then sought in particulate matter, sediment, and microbial mat samples. The results obtained supported the significance of photochemical oxidation and autoxidation of phytoplanktonic chlorophyll phytyl side chain in the marine environment.
Protective action of CLA against oxidative inactivation of paraoxonase 1, an antioxidant enzyme
Authors: Su Nguyen‐Duy , Liu Xi‐Wen , Kim Mee Ree , Jeong Tae‐Sook , Sok Dai‐Eun 
Published: November 2006

AbstractThe effect of CLA on paraoxonase 1 (PON1), one of the antioxidant proteins associated with HDL, was investigated for its protective action against oxidative inactivation as well as its stabilization activity. When cis‐9 (c9),trans‐11 (t11)‐CLA and t10,c12‐CLA were examined for their protective activity against ascorbate/Cu2−‐induced inactivation of PON1 in the presence of Ca2+, two CLA isomers exhibited a remarkable protection (Emax, 71–74%) in a concentration‐dependent manner (50% effective concentration, 3–4 μM), characterized by a saturation pattern. Such a protective action was also reproduced with oleic acid, but not linoleic acid. Rather, linoleic acid antagonized the protective action of CLA isomers in a noncompetitive fashion. Additionally, the two CLA isomers also protected PON1 from oxidative inactivation by H2O2 or cumene hydroperoxide. The concentration‐dependent protective action of CLA against various oxidative inactivation systems suggests that the protective action of CLA isomers may be mediated through their selective binding to a specific binding site in a PON1 molecule. Separately, the inactivation of PON1 by p‐hydroxymercuribenzoate (PHMB), a modifier of the cysteine residue, was also prevented by CLA isomers, suggesting the possible existence of the cysteine residue in the binding site of CLA. The c9,t11‐CLA isomer seems to be somewhat more effective than t10,c12‐CLA in protecting against the inactivation of PON1 by either peroxides or PHMB, in contrast to the similar efficacy of these two CLA isomers in preventing ascorbate/Cu2+‐induced inactivation of PON1. Separately, CLA isomers successfully stabilized PON1, but not linoleic acid. These data suggest that the two CLA isomers may play a beneficial role in protecting PON1 from oxidative inactivation as well as in its stabilization.
Vaccenic acid (t11–18∶1) is converted to c9,t11‐CLA in MCF‐7 and SW480 cancer cells
Authors: Miller Aine , McGrath Emma , Stanton Catherine , Devery Rosaleen 
Published: November 2006

AbstractThe aims of this study were to determine whether vaccenic acid (VA; t11–18∶1) is converted to c9,t11‐CLA in human mammary (MCF‐7) and colon (SW480) cancer cell lines and whether VA influences cell viability and other CLA‐bioresponsive markers. When cells were incubated in the presence of VA at concentrations of 5 to 20 μg/mL, both VA and c9,t11‐CLA increased in cellular lipids in a dose‐dependent manner. After 4 d of incubation of SW480 and MCF‐7 cells with VA (20 μg/mL), c9,t11‐CLA increased from undetectable levels to 8.57 and 12.14 g/100 g FAME in cellular lipids, respectively. VA supplementation for 4 d at 5, 10, and 15 μg/mL had no effect on cell growth, whereas 20 μg/mL significantly (P<0.05) reduced cell growth in both cell lines. VA (20 μg/mL) treatment induced DNA fragmentation and significantly (P<0.05) depeleted cytosolic GSH levels in the SW480 cell line after 4 d of incubation, suggesting that apoptosis was the mode of cell death induced by VA. Both VA and c9,t11‐CLA reduced (P<0.05) total ras expression in SW480 cells. 14C‐Arachidonic acid uptake into the MG fraction was significantly increased (P<0.05) in both cell lines while uptake into the phospholipid fraction decreased in response to VA. VA treatment significantly (P<0.05) increased 8‐epi‐prostaglandin F2α in both cell lines. The data indicate that growth suppression and cellular responses of both cells lines are likely mediated by VA desaturation to c9,t11‐CLA via Δ9‐desaturase.