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PubMed2002

Dietary oils high in oleic acid but with different unsaponifiable fraction contents have different effects in fatty acid composition and peroxidation in rabbit LDL.

OBJECTIVE: We investigated the influence of different edible oils high in oleic acid but with different unsaponifiable fractions on the fatty acid composition and lipid peroxidation in plasma and low-density lipoprotein (LDL) in rabbits. METHODS: Thirty-two rabbits were randomly assigned to four groups of eight animals. For 8 wk each group was fed a semisynthetic isoenergetic diet that differed by lipid source (Picual virgin olive oil, Picual virgin olive oil that had been subjected to an exhaustive process of washing, Arbequina virgin olive oil, and sunflower oil high in oleic acid). We analyzed the fatty acid profile, thiobarbituric acid reactive substances, alpha-tocopherol, coenzyme Q, and retinol in plasma and the fatty acid profile, hydroperoxides, alpha-tocopherol, and coenzyme Q in LDL. RESULTS: The two varieties of virgin olive oil behaved differently from the high-oleic sunflower oil, and the effect of the different ratios of oleic acid to linoleic acid in the lipid sources on fatty acid composition in plasma and LDL was significant. With regard to oxidative stress, LDL in the group that ingested the lipid sources with the greatest amount of phenolic compounds showed the highest level of antioxidants (alpha-tocopherol and coenzyme Q; P < 0.05) and the lowest susceptibility to lipid peroxidation (P < 0.05). CONCLUSION: This study provides evidence in vivo of the considerable antioxidant capacity of the phenolic fraction of virgin olive oil in rabbit LDL and the important role that this unsaponifiable fraction can play in the overall antioxidant benefit attributed to these oils. However, these effects depend on the phenolic content of the oil.

Animals↗
PubMed1994

Dietary linoleic, alpha-linolenic and oleic acids are oxidized at similar rates in rats fed a diet containing these acids in equal proportions.

The objective of this study was to examine whether whole body oxidation rates of dietary linoleic, alpha-linolenic and oleic acids differ when the acids are provided in identical quantities. Male rats were fed for 10 wk a 15% fat (w/w) diet containing equal amounts of linoleic, alpha-linolenic and oleic acids (22.7, 23.0 and 23.2% of total fatty acids, respectively). At week 10, after overnight fasting, rats were intragastrically administered 20 microCi of either [1-14C]-labelled linoleic, alpha-linolenic or oleic acid in a 200-microL bolus of oil containing equal quantities of each fatty acid. The appearance of 14CO2 in expired air was then monitored hourly for 12 h for each animal. A preliminary study had shown that growth and food consumption patterns in animals consuming the oil containing equal quantities of each of the fatty acids paralleled the patterns of animals that were self-selecting among separate diets, each of which contained one of the component oils. The appearance of 14C, expressed as percent dose administered, peaked at 2-3 h post-dose for 14C-labelled linoleic (5.28 +/- 0.37%/h), alpha-linolenic (6.92 +/- 0.51%/h) and oleic (5.98 +/- 0.44%/h) acids. Statistically these values were not significantly different. Cumulative 14CO2 excretion rates over 12 h were also similar for linoleic (27.2 +/- 0.9%), alpha-linolenic (26.8 +/- 1.2%) and oleic (25.9 +/- 1.2%) acids. The results suggest that the rat's capacity to oxidize 18-carbon unsaturated fatty acids is not affected by fatty acid unsaturation when these fatty acids are provided at equal dietary levels.

Animals↗
PubMedDate not supplied

[Effect of oleic acid and Tween-80 on lysine synthesis by the culture Corynebacterium glutamicum].

The effect of oxidized and unoxidized oleic acid and Tween-80 on the growth and lysine synthesis by the producers C. glutamicum strains 95, 8, 28 was investigated. Surface active substances like oxidized and unoxidized oleic acid and Tween-80 during cultivation of the lysine producers on the glucose medium (the synthetic medium) and the medium with molasses and corn extract either inhibited the culture growth, thus reducing lysine yield, or accelerated the culture growth, thus increasing lysine yield. Oxidized and unoxidized oleic acid produced the greatest effect when added to the nutrient medium on the 48th cultivation hour. The increment of synthesized lysine was 120-150% of the control. Tween-80 proved to be very effective when added at early stages of fermentation (20 hours).

Corynebacterium↗
PubMed2002

Experimental cerebral fat embolism: embolic effects of triolein and oleic acid depicted by MR imaging and electron microscopy.

BACKGROUND AND PURPOSE: In fat embolism, free fatty acid is more toxic than neutral fat in terms of tissue damage. We evaluated the hyperacute embolic effects of triolein and oleic acid in cat brains by using MR imaging and electron microscopy. METHODS: T2-weighted imaging, diffusion-weighted imaging, and contrast-enhanced T1-weighted imaging were performed in cat brains after the injection of triolein (group 1, n = 8) or oleic acid (group 2, n = 10) into the internal carotid artery. MR images were quantitatively assessed by comparing the signal intensity ratios of the lesions with their counterparts on T2-weighted images, apparent diffusion coefficient (ADC) maps, and contrast-enhanced T1-weighted images. Electron microscopic findings in group 1 were compared with those in group 2. RESULTS: Qualitatively, MR images revealed two types of lesions. Type 1 lesions were hyperintense on diffusion-weighted images and hypointense on ADC maps. Type 2 lesions were isointense or mildly hyperintense on diffusion-weighted images and isointense on ADC maps. Quantitatively, the signal intensity ratios of type 1 lesions in group 2 specimens were significantly higher on T2-weighted images (P =.013)/(P =.027) and lower on ADC maps compared with those of group 1. Electron microscopy of type 1 lesions in both groups revealed more prominent widening of the perivascular space and swelling of the neural cells in group 2, in contrast to notable endothelial defects in group 1. CONCLUSION: MR and electron microscopic data on cerebral fat embolism induced by either triolein or oleic acid revealed characteristics suggestive of both vasogenic and cytotoxic edema in the hyperacute stage. Tissue damage appeared more severe in the oleic acid group than in the triolein group.

Animals↗
PubMed2000

Structural and functional effects of oleic acid and iontophoresis on hairless mouse stratum corneum.

The aim of this study was to assess the effects of chemical and electrical modes of percutaneous penetration enhancement on the intercellular lipid lamellae of the stratum corneum. Hairless mice were treated with either oleic acid/propylene glycol and iontophoresis separately or together. Permeability barrier function was evaluated by measuring transepidermal water loss and correlated with the structure of stratum corneum intercellular lamellae, as evaluated by electron microscopy, using ruthenium tetroxide postfixation. Transepidermal water loss levels did not change following 1 h iontophoresis alone. In contrast, topical applications of 0.3 M oleic acid in propylene glycol for 1 h increased transepidermal water loss significantly. Moreover, the combined use of iontophoresis plus 0.3 M oleic acid for 1 h further increased transepidermal water loss at equivalent time points. Ultrastructural observations demonstrated both marked disorganization of the intercellular lipid lamellae, as well as the presence of distended lacunae within the stratum corneum in oleic acid/propylene glycol plus or minus iontophoresis-treated stratum corneum. This study provides direct evidence that the oleic acid/propylene glycol system can disrupt the stratum corneum lipid lamellar structures, and that coapplications of oleic acid with iontophoresis further enhance the effects of oleic acid. The synergy between chemical and physical enhancement may afford a new approach to promote transdermal drug delivery.

Animals↗
PubMed1999

Milrinone improves arterial oxygenation in dogs with acute lung injury induced by oleic acid.

The aim of the study was to investigate effects of milrinone on pulmonary permeability in dogs with acute lung injury induced by oleic acid. To induce acute lung injury, we administered 0.08 mg/kg of oleic acid to 19 adult mongrel dogs and then measured hemodynamic parameters and performed blood gas analysis. An injection of oleic acid depressed the mean arterial pressure, cardiac index, and arterial oxygenation. Dogs were divided into three groups: six received a bolus of milrinone (50 microg/kg) followed by a continuous (0.5 microg/kg/min, low-dose), seven received a bolus (100 microg/kg) followed by a continuous (1.0 microg/kg/min; i.e., a low-dose twice; high-dose), and six no milrinone (control). Milrinone administration improved the cardiac index and arterial oxygenation and simultaneously depressed the intrapulmonary shunt fraction and the extravascular thermal lung water as extravascular water content of the lung. These changes produced by milrinone are different according to the doses. In conclusion, milrinone acts on the capillary endothelium and inhibits an accumulation in the extravascular water content of the lung, which may induce an improvement in arterial oxygenation. Milrinone may also improve arterial oxygenation through an inhibition of platelet aggregation and chemical mediators that are released from platelets. The latter mechanism also may improve arterial oxygenation, and the exact property responsible for causing the effect of milrinone has not yet been identified.

Animals↗
PubMed1989

Effects of oleic acid and oleyl alcohol on cholecystokinin and secretin in plasma and pancreatobiliary secretion.

To evaluate the importance of the terminal carboxy group of the oleic acid molecule in the release of secretin and cholecystokinin (CCK) to plasma, six normal persons were stimulated twice with duodenal perfusates containing either 20 mM oleic acid or 20 mM oleyl alcohol. Oleic acid increased the pancreatic secretion of bicarbonate and amylase and the concentrations of secretin and CCK in plasma and provoked gallbladder emptying. Oleyl alcohol only increased the amylase output slightly, but significantly. It is concluded that the carboxy group of the fat molecule has an important role in triggering the release of secretin and CCK to plasma.

Adult↗
PubMed1988

The ionization and distribution behavior of oleic acid in chylomicrons and chylomicron-like emulsion particles and the influence of serum albumin.

A reproducible, fairly narrow-sized population of rat lymph chylomicrons, approximately 100 nm, was isolated by centrifugation and combined with low levels of [1-13C]oleic acid for NMR studies. The carboxyl chemical shift was monitored as a function of aqueous pH to characterize the ionization behavior of the fatty acid in these particles. The titration curves were very similar to those for oleic acid in equivalent-sized emulsion particles composed of egg phosphatidylcholine and triolein. A simple partition-ionization model was fitted to the data to derive values for apparent ionization constant, expressed as pKapp, of 7.4-7.5 and the "true" surface to core partition coefficient of approximately 7 for oleic acid in chylomicrons. The fatty acid in chylomicrons thus appeared to be largely associated with the surface regions of these particles. Addition of bovine serum albumin to the samples showed that near physiologic pH much of the fatty acid was bound to the albumin at fatty acid to albumin-binding stoichiometries as high as 5.1 and with mass ratios of greater than 2 in favor of the lipid or lipoprotein particles. Lowering the pH of the medium shifted the distribution of fatty acid away from albumin so that at pH 5 with the emulsion, virtually all the fatty acid was associated with the lipid. The behavior observed under physiologic conditions is consistent with the rapid clearance and redistribution of fatty acid generated in these particles by lipolytic processes. However, under conditions of severe acidosis, hyperlipidemia, and hypoalbuminemia a significant portion of fatty acids might be retained in triglyceride-rich lipoproteins and their remnants and affect subsequent metabolism.

Algorithms↗
PubMed1994

[Effects of inverse ratio ventilation and positive end-expiratory pressure on gas exchanges in dogs with oleic acid induced pulmonary edema].

The purpose of this study was to determine the effect of inverse ratio ventilation (IRV) on gas exchanges and circulatory systems in 56 mongrel dogs with oleic acid induced pulmonary edema. The dogs were divided into 9 groups and were ventilated with 9 kinds of ventilatory modes such as I:E ratio of 1:2 (control), 2:1 (2:1 IRV), 3:1 (3:1 IRV), 1:2 with 5 cmH2O PEEP (1:2 PEEP 5), 2:1 with 5 cmH2O PEEP (2:1 PEEP 5), 3:1 with 5 cmH2O PEEP (3:1 PEEP 5), 1:2 with 10 cmH2O PEEP (1:2 PEEP 10), 2:1 with 10 cmH2O PEEP (2:1 PEEP 10) and 3:1 with 10 cmH2O PEEP (3:1 PEEP 10), using a Servo ventilator 900C. IRV could not improve arterial oxygenation in dogs with oleic acid induced pulmonary edema, but PEEP could significantly improve arterial oxygenation depending on PEEP level. Although in the control group, PaCO2 increased gradually, PaCO2 was kept constant for 8 hours in the 3:1 IRV groups. In the 2:1 group, PaCO2 did not change significantly until 6 hours, but in IRV with 10 cmH2O PEEP groups, PaCO2 showed the highest increase. There was no significant alteration in hemodynamics after ventilatory modes were changed to IRV. Although oxygen delivery was the best in the 3:1 IRV group, there was no statistical significance between the 3:1 IRV group and others. It was concluded that IRV did not improve arterial oxygenation but showed a favorable effect for CO2 elimination, in dogs with oleic acid induced pulmonary edema.

Animals↗
PubMed1995

Oleic acid transformations by selected strains of Sphingobacterium thalpophilum and Bacillus cereus from composted manure.

In a survey of 186 randomly selected microbial strains isolated from composted manure, 63 transformed oleic acid into three types of products: hydroxy fatty acid, fatty amide, and less polar oleyl lipid. Selection of oleic acid-transforming microorganisms was enhanced in nutrient agar supplemented with 0.1% (vol/vol) oleic acid at pH 7.2. Most of the 63 diverse isolates elicited inconsistent and poorly reproduced transformations. However, strains 142b (NRRL B-14797) transformed oleic acid to 10-hydroxystearic acid consistently, and strain 229b (NRRL B-14812) produced an octadecenamide. Taxonomic studies indicated that NRRL strain B-14797, possessing 1,3-dihydroxy-2-amino-15-methylhexadecane and sphinganine bases, was closely related to Sphingobacterium thalpophilum, and NRRL B-14812 was identified as Bacillus cereus.

Bacillus cereus↗
PubMed1990

Regulation of platelet protein kinase C by oleic acid. Kinetic analysis of allosteric regulation and effects on autophosphorylation, phorbol ester binding, and susceptibility to inhibition.

The regulation of protein kinase C by oleic acid was studied, and parameters that characterize the activation of protein kinase C by oleic acid and distinguish its effects from those of diacylglycerol (DAG) and phosphatidylserine (PS) were delineated. Activation of protein kinase C by sodium oleate required the presence of calcium and showed mild cooperative behavior (Hill number of 1.25) suggesting that Ca(oleate)2 is the active species. Kinetic analysis of the interaction of sodium oleate with substrates indicated that sodium oleate acted to increase the activity of the enzyme without modulating the KM for either MgATP or histone substrates. In this respect, sodium oleate action resembled that of DAG but not PS. However, multiple parameters distinguished the effects of sodium oleate from those of DAG. Unlike DAG, sodium oleate was unable to inhibit phorbol dibutyrate binding to protein kinase C. Sodium oleate also failed to interact with micelle-bound protein kinase C and preferentially activated "soluble" protein kinase C. The addition of histone caused protein/lipid aggregation in the presence of DAG but not in the presence of oleate. Activation of protein kinase C by sodium oleate or by PS/DAG demonstrated differential susceptibility to the action of inhibitors. Sphingosine and NaCl were more potent in inhibiting activation of protein kinase C by PS/DAG than by sodium oleate. Sodium oleate also expressed PS-like activity in that calcium and oleate acted as cofactors in activation of protein kinase C by DAG. Similar to PS, the ability of oleate to act in synergy with DAG resulted from "competitive" activation with a decrease in KM(app) of protein kinase C for DAG. Finally, sodium oleate was unable to induce autophosphorylation of protein kinase C. These studies demonstrate that oleate activates protein kinase C by a mechanism that is distinct from PS/DAG but partially overlaps the kinetic effects of both PS and DAG. The significance of these studies is discussed in relation to mechanisms of protein kinase C activation and to the possible physiological relevance of activation of protein kinase C by fatty acids.

Adenosine Triphosphate↗
PubMed2003

Comparison between oleic acid and docosahexaenoic acid binding to interphotoreceptor retinoid-binding protein.

Interphotoreceptor retinoid-binding protein (IRBP), which binds retinoids and fatty acids, is the major soluble protein in the interphotoreceptor matrix (IPM) but its role remains ambiguous. Using competitive fluorescence and tryptophan-quenching assays we found oleic acid and other cis-monounsaturated fatty acids bind much more strongly than does docosahexaenoic acid to bovine IRBP. IPM's fatty acid composition was determined: it was richer in oleic acid than either the retinal pigment epithelium or rod outer segments. This may imply oleic acid has a key role in the balance and transport of retinoids and fatty acids in the retina.

Animals↗
PubMedDate not supplied

Acute lung injury using oleic acid in the laboratory rat: establishment of a working model and evidence against free radicals in the acute phase.

OBJECTIVE: To determine the optimal model of acute respiratory distress syndrome (ARDS) using oleic acid in our laboratory and to measure the presence or absence of free radicals in this model. DESIGN: This protocol consisted of 2 phases. During the first phase, various conditions were tested, to include different doses (30 or 50 microliters) of oleic acid, different levels of support (with and without mechanical ventilation), and different injury time periods (sacrifice 4 or 8 hours after injection). During the second phase, animals were randomly assigned to experimental (injured) and control (noninjured) groups for the measurement of free radicals by nitrotyrosine Western blot and by the conversion of hydroethidine to ethidium bromide by superoxide. SETTING: Multidisciplinary laboratory and animal surgery suite. PARTICIPANTS: Twenty-seven male Sprague-Dawley rats. RESULTS: During the first phase, several animal deaths occurred in the high-dose, ventilated groups, whereas there were no deaths in the nonventilated animals. On hematoxylin and eosin stain, injury was greatest in the animals that received the higher dose of oleic acid and that were sacrificed at 8 hours. In the protocol's second phase, oxygen radical assays were negative for all experimental and control lungs. CONCLUSIONS: During this study, we successfully established a working animal model of ARDS for our laboratory. Our findings to date suggest that free radicals do not contribute to oleic acid lung injury in the early stages.

Animals↗
PubMed1989

Synergistic inhibition of metabolic cooperation by oleic acid or 12-0-tetradecanoylphorbol-13-acetate and dichlorodiphenyltrichlorethane (DDT) in Chinese hamster V79 cells: implication of a role for protein kinase C in the regulation of gap junctional intercellular communication.

The effects of TPA and/or DDT and oleic acid and/or DDT on gap junction-mediated intercellular communication (i.e. metabolic cooperation) between Chinese hamster V79 cells was examined. Addition of TPA, DDT or oleic acid alone to cocultures of 6-thioguanine-resistant (6-TGR) and 6-thioguanine-sensitive (6-TGS) V79 cells significantly increased the recovery of 6-TGR cells indicating inhibition of metabolic cooperation. In the presence of TPA and DDT or oleic acid and DDT the observed recovery of 6-TGR cells was significantly greater than the expected (calculated) additive 6-TGR cell recovery. No synergistic increases in 6-TGR cell recovery were observed when co-cultures of V79 cells were exposed to dieldrin and DDT. These results indicate that TPA and DDT or oleic acid and DDT can act synergistically to inhibit metabolic cooperation. These data suggest a role for protein kinase C in the regulation of gap junction-mediated intercellular communication.

Animals↗
PubMed1985

Uptake of radiolabelled alpha-linolenic, arachidonic and oleic acid in tissues of normal and essential fatty acid-deficient rats--an autoradiographic study.

Rats fed diets with a low (0.3% of total energy) or normal (3%) essential fatty acid (EFA) content were injected intravenously with a single dose of 14C-labelled alpha-linolenic, arachidonic or oleic acid and the distribution of radioactivity in the tissues was compared 5 min, 1 h and 18 h after the application using whole-body autoradiography. The highest levels of labelling with all fatty acids were observed in the liver, brown fat and adrenal cortex. Specific for arachidonic acid was a high and consistent concentration of radioactivity in the myocardium at all times and for oleic acid in the white fat after 18 h. The tissue uptake of arachidonic acid was similar in both dietary groups, whereas a higher accumulation of alpha-linolenic was seen in most of the tissues in the low EFA group after 18 h compared to the normal EFA group. The uptake of oleic acid was higher in some tissues in the low EFA than in the normal EFA group after 1 h, but after 18 h these differences had disappeared almost completely.

Animals↗
PubMed1998

Erythrocyte membrane stearic to oleic acid ratio in carcinoma of the gallbladder: a preliminary study.

AIMS: The role of erythrocyte membrane stearic to oleic acid ratio (saturation index) as a marker of malignancy is still unclear, though an association has been found in colorectal carcinoma, bronchogenic carcinoma, leukaemia, lymphoma and in hepatic malignancies. This study aims to investigate the role of the saturation index in primary carcinoma of the gallbladder. METHODS: This paper describes the results of the stearic to oleic acid ratio determination in 26 subjects with either cholelithiasis or carcinoma of the gallbladder, also including a group of age- and sex-matched controls, using gas chromatography. This is the first report of the saturation index in carcinoma of the gallbladder. RESULTS: A significantly lower saturation index was observed in patients with carcinoma of the gallbladder than with cholelithiasis (t = 2.19, P = 0.043, T = 47, P < 0.05, Wilcoxon P < 0.001, F = 2192.23, P < 0.001; 95% CI 18.45-30.44) and controls (t = 2.5, P = 0.024, T = 36, P < 0.05, F = 10904.11, P < 0.001, Wilcoxon P < 0.001; 95% CI 52.42-63.39). Among the carcinoma patients a further lowering was noted in stage IV disease compared with stage III (T = 6, P < 0.05). CONCLUSIONS: These changes are probably due to a marked increase in oleic acid content at the expense of stearic acid. This lowering of the saturation index in carcinoma of the gallbladder is similar to that observed previously in the other malignancies.

Carcinoma↗
PubMed1989

Effects of toxin II from the scorpion Androctonus australis Hector on sodium current in neuroblastoma cells and their modulation by oleic acid.

The effects of toxin II (AaH II) isolated from the scorpion Androctonus australis Hector on sodium current in neuroblastoma X glioma NG 108-15 hybrid cells were analysed under patch clamp conditions in the whole cell configuration. AaH II (70 nM) induced a maintained sodium current, as well as increasing both fast and slow inactivation time constants and the amplitude of the peak current. This latter effect occurred via a shift of the activation-voltage curve towards negative voltage values by about 9 mV. Oleic acid (5 microM), which had no effect on INa under control conditions, decreased the AaH II-induced maintained current. It also reversed, or prevented the increase of the peak current induced by AaH II. However, it neither prevented nor modified the AaH II-induced increase in inactivation time constants. The binding of the toxin to its specific site and the number of binding sites for AaH II were not significantly modified by oleic acid. The oleic acid-induced effects could not be related to the activation of protein kinase C since PMA, a potent activator of this enzyme, did not produce oleic acid-like effects. From these results, it is concluded that AaH II has several independent effects on sodium channels, some of which could be modulated by the lipid environment of sodium channels in the membrane.

Animals↗
PubMed1963

THE ABSORPTION OF OLEIC ACID IN THE BILE FISTULA RAT.

A technique is described for collecting thoracic duct lymph in a portable glass saddle from an unrestrained rat. Uniformly labelled oleic acid in various physical states was given to rats with thoracic duct and bile fistulae to study the influence of bile salts on the amount absorbed and on the route of transport and esterification after absorption. It is suggested that in addition to their emulsifying action bile salts may stimulate the esterification of absorbed oleic acid by the intestinal mucosa.

Absorption↗