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PubMed1989

Cluster headache: incorporation of (1-14C)oleic acid into phosphatidylserine in polymorphonuclear cells.

As recently demonstrated by our group, polymorphonuclear cells (PMNs) from cluster headache patients have an increased ability to incorporate arachidonic acid (AA) and L-serine into phosphatidylserine (PS). To evaluate whether there is an increased incorporation into PS also from fatty acids not involved in eicosanoid metabolism, PMNs from controls (n = 14) and cluster headache patients (n = 12) were incubated with (1-14C)oleic acid. After 1 h 2.7% +/- 1.1 (mean value +/- SD) of the glycerophospholipid radioactivity was found in PS in controls, whereas 4.2% +/- 1.2 was found in cluster headache patients (p less than 0.005). For phosphatidylcholine (PC) the corresponding figures were 74.2 +/- 5.4 in controls and 66.7 +/- 7.6 in cluster headache patients (p less than 0.01). The results suggest that the de novo biosynthesis of PS is increased and the biosynthesis of PC is decreased in cluster headache. The results may have an effect on the role of PS as an obligate protein kinase C activator.

Adult↗
PubMed1990

Effect of albumin on oleic acid lymphatic absorption in rats.

1. The aim of this study was to investigate how fatty acid absorption was affected when exogenous fatty acids were complexed with albumin in absence of bile. Experiments were carried out in vivo, in order to study overall absorption processes. 2. An equimolar mixture of 14C oleic acid, palmitic acid and monopalmitin was infused intraduodenally in bile- and pancreatic juice-diverted rats. 3. Lipids were emulsified with either sodium taurocholate or fatty acids complexed with albumin. 4. Lymphatic lipid output was compared during the 6 hr following infusion of 90 mumol of the radioactive lipid mixture. 5. Lymphatic radioactive lipid recovery was significantly decreased by albumin. 6. Only 17% of the infused radioactivity was recovered in lymph when fatty acids were complexed with albumin against 37% when lipids were emulsified with sodium taurocholate. 7. Unrecovered lymph radioactivity was found at the distal part of intestine. Moreover, albumin significantly decreased lymph flow. 8. We conclude that undigested albumin acted at the luminal level of lipid absorption processes and specifically decreased fatty acid uptake.

Absorption↗
PubMed2000

Identification and enumeration of oleic acid and linoleic acid hydrating bacteria in the rumen of sheep and cows.

The diversity and population densities of facultative anaerobic bacteria with the capacity to hydrate oleic acid and linoleic acid in the rumen of sheep and dairy cows were determined. The screening of representative colonies, from rumen fluid plated aerobically on a range of agar media, revealed that sheep rumen fluid contained hydration-positive strains of Streptococcus, Staphylococcus, Enterococcus, Lactobacillus and Pediococcus, whereas cow rumen fluid contained hydration-positive strains of Streptococcus, Lactobacillus and Staphylococcus. Mean counts of facultative anaerobic bacteria in sheep and cattle rumen were log10 7.29 and log10 6.40, respectively, and were independent of diet. Approximately 56% of facultative anaerobic bacteria were able to hydrate oleic and/or linoleic acid in anaerobic broth culture. For both sheep and cows, the most numerous hydration-positive isolates were strains of Strep. bovis. The results, which are the first to show that pediococci have the capacity to hydrate unsaturated fatty acids, suggest that lactic acid bacteria are the major unsaturated fatty acid hydrating bacteria in the rumen.

Animals↗
PubMed1987

Mechanism of pH effect on oleic acid and cholesterol absorption in the rat.

Previous experiments [K. Chijiiwa and W. G. Linscheer, Am. J. Physiol. 246 (Gastrointest. Liver Physiol. 9): G492-G499, 1984] have shown higher rates of absorption of oleic acid (OA) and cholesterol (CH) from micellar solutions perfused through segments of small bowel at pH 5.5 than at pH 6.5. Both solutions contained equal amounts of these lipids in addition to sodium taurocholate (30 mM). It was hypothesized that there may be two reasons to explain this observation. First, the micelles of one of the two solutions (pH 6.5) became depleted of these lipids during the perfusion procedure, while the micelles of the other solution (pH 5.5) were kept saturated with these lipids by the presence of emulsified particles in the perfusate. Second, the pH difference resulted in a much lower ratio of protonated vs. ionized OA in the pH 6.5 solution. Most investigators assume that primarily protonated fatty acid (FA) is absorbed and very little ionized FA is absorbed. The purposes of the present study are to evaluate further the factor of lipid saturation of the micelles by comparison of rates of absorption from two partially lipid-depleted micellar solutions containing equal amounts of OA and CH, in which the micelles of one solution were much more lipid depleted than the micelles of the other. This was caused by the pH difference. The second purpose is to evaluate the effect of the pH-related difference in protonate vs. ionized OA on absorption of OA from nonmicellar aqueous solutions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Role of dietary oleic acid in linoleic acid-enhanced metastasis of a mouse mammary tumor.

We have previously shown that a high fat diet (20% w/w) containing 12% linoleic acid (18:2) can significantly increase the metastasis of mammary tumor cells when compared with high fat diets that contain 8% or less 18:2 with a constant level of oleic acid (18:1). This effect may have been due to an alteration of eicosanoid metabolism because the cyclooxygenase inhibitor, indomethacin, abolished the increase. Because 18:1 may interfere with the metabolism of 18:2 to 20:4, we have now tested whether the 18:1 that supplements the 18:2 diet can have an effect on spontaneous or experimental metastasis of the line 4526 murine mammary tumor. For this, six 20% fat diets were formulated with 1%, 6%, and 12% 18:2 and either high or low levels of 18:1. Our results indicate that the amount of select fatty acids other than 18:2 at 12% has no significant effect on mouse growth, tumor growth, or tumor latency. When spontaneous metastatic burden was calculated, no significant differences between mice fed diets containing 1% and 6% 18:2 were observed. However, 4 to 5 times more of a metastatic burden was observed in mice fed diets containing 12% 18:2. No significant differences were observed between high and low 18:1 diets when the 18:2 content was 1 or 12%. However, at 6% 18:2, 18:1 significantly decreased metastatic burden. When experimental metastasis was assessed, relatively low levels of surface lung nodules were observed at 1% and 6% 18:2, but significantly higher levels were observed at 12% 18:2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

A positron emission tomographic comparison of diffuse and lobar oleic acid lung injury.

We tested whether severity of injury measured from the pulmonary transcapillary escape rate for transferrin (PTCER), lung water accumulation, and changes in regional pulmonary blood flow (PBF) would be similar after oleic acid (OA) injection into either all lung lobes or directly into the pulmonary artery feeding the left caudal lobe (LCL) only. Measurements were made with positron emission tomography. After 0.015 ml/kg OA was injected into the LCL (Lobar, n = 5), lung water increased in the left dorsal region from 37 +/- 5 to 50 +/- 8 ml/100 ml lung (P less than 0.05), PTCER was 533 +/- 59 10(-4)/min, and regional PBF decreased 62%. No significant change occurred in the uninjured right dorsal lung where PTCER was 85 +/- 32. In the left ventral region PTCER was 357 +/- 60, PBF decreased only 31%, and the increase in lung water was less (25 +/- 3 to 30 +/- 6). In contrast after 0.08 ml/kg OA was injected via the right atrium (Diffuse, n = 6), PTCER (283 +/- 94) was lower in the left dorsal region of this group than in the corresponding region of the Lobar group (P less than 0.05). The increase in lung water, however, was the same, but no change occurred in PBF distribution. These results indicate important differences between the two methods of causing lung injury with OA. After injury lung water accumulates primarily in dependent portions of lung and is not always accompanied by a decrease in regional PBF. These decreases, when they occur, may instead indicate severe vascular injury.

Animals↗
PubMed1989

Characterization of plasma-stabilized liposomes composed of dioleoylphosphatidylethanolamine and oleic acid [published errtum appears in Biochem Biophys Res Commun 1989 Sep 29;163(3):1539].

We have previously reported that small unilamellar liposomes (d less than or equal to 200 nm) composed of dioleoylphosphatidylethanolamine and oleic acid can be stabilized by incubating with normal human plasma (Liu and Huang, Biochemistry 1989, in press). The stabilized liposomes were very stable even under relatively harsh conditions such as extreme pH, high salt and trypsin treatment. Fluorescence depolarization of diphenylhexatriene showed that the stabilized liposome had a high microviscosity in the lipid core, which did not decrease even after the majority of proteins were removed by trypsin. These data suggest that plasma proteins inserted into the lipid bilayer are probably responsible for the stabilization activity. After i.v. injection into mouse, stabilized liposomes showed a relatively low affinity to liver and spleen as compared to a conventional liposome composition.

Animals↗
PubMed1980

Failure of indomethacin to prevent or ameliorate oleic acid pulmonary edema in the dog.

The possibility that prostaglandin synthesis inhibition might favorably inhibit the development of animal adult respiratory distress syndrome models was investigated in two groups of dogs; one group was pretreated with indomethacin 3 mg/kg. Both groups received oleic acid 0.15 mg/kg. Measurements of gas exchange and hemodynamics were performed every hour for 5 hours following embolization. Severe pulmonary edema developed in both groups. The indomethacin pretreated group responded similarly to the control group; there was no difference in the 5 hour course of Pa02 (p = .34), P(A-a)02 (p = .21) or QS/QT (p = .99). Prostaglandin synthesis inhibition did not favorably influence the immediate development of acute respiratory failure following oleic acid.

Animals↗
PubMed1990

Effects of aerosolized artificial surfactant on repeated oleic acid injury in sheep.

We studied the effects of an artificial surfactant, Exosurf, administered as an aerosol on respiratory system compliance (Crs), total respiratory resistance (RT), and gas exchange (PO2) in anesthetized, paralyzed sheep with oleic acid (OA)-induced lung injury. Paired experiments with OA were performed in 10 sheep, 5 of which received Exosurf in the first experiment and aerosolized 0.9% NaCl in the second; in the other 5 sheep the order of Exosurf and NaCl was reversed. Paired experiments without OA were performed in 6 additional sheep that served as controls. In the first set of experiments, OA caused significant abnormalities, compared to control and baseline values (p less than 0.02), in Crs, RT, and PO2; there was no difference between animals that received Exosurf and those that received NaCl. Baseline values for PO2 and Crs during the second set of experiments with OA were lower than controls (p less than 0.002), indicating that the animals had not fully recovered from their initial injury. After OA, the animals that received NaCl (i.e., the ones that received Exosurf the first time) had higher PO2 and Crs values (p less than 0.01) than those that received NaCl first and Exosurf second. There was no difference in postmortem lung water content between the animals that received Exosurf or NaCl first, both of which were higher than control (p less than 0.01). Studies in 3 additional sheep showed peripheral deposition of aerosol. Thus, we failed to show an acutely beneficial effect of aerosolized Exosurf in OA-induced lung injury; Exosurf did, however, appear to provide protection against some of the consequences of repeated lung injury.

Aerosols↗
PubMed1996

Partition of oleic acid between the lymph and portal blood in rats having a diverted bile-pancreatic duct.

The present study examines the suggestion that in the absence of adequate bile and pancreatic juice, which support the absorption from the gut of long-chain fatty acids into lymph, the fatty acids are absorbed directly into the portal blood. Oleic acid (18:1) partitioning between lymph and portal blood was investigated in intact and bile- and pancreatic juice-diverted rats. In a first set of experiments, 18:1 absorption from the gut into lymph and blood was studied by continuous recovery of the mesenteric lymph for 6 h and mesenteric portal venous blood for 1 h. In a second set of experiments, esterification processes were investigated by study of the mucosal distribution of labelled lipids and by mono- and diacylglycerol acyltransferase (EC 2.3.1.22 and EC 2.3.1.20 respectively) specific activities. In the bile- and pancreatic juice-diverted rats the absorption of labelled 18:1 into lymph was significantly reduced during the first 3 h of intraluminal infusion of this substrate. In such rats a compensatory absorption of labelled 18:1 into mesenteric portal blood was not observed. At 6 h after micellar lipid-mixture infusion, the overload of lipids both in free form and as triacylglycerols persisting in the mucosa paralleled the lower acyltransferase specific activities observed in bile- and pancreatic juice-diverted rats. These studies demonstrate the absence of a previously proposed compensatory absorption of 18:1 into portal blood when absorption into lymph is impaired by an inadequate supply of bile and pancreatic juice.

Animals↗
PubMed1969

Method for continuous intravenous infusion of large amounts of oleic acid into rats.

A method has been developed for the continuous intravenous infusion of large amounts of oleic acid into rats. The acid was infused in the form of an emulsion prepared by sonication and stabilized with albumin in low concentration. Fatty acid was infused at a rate equal to the turnover rate of endogenous free fatty acids and the infusion was continued for 3 hr. During this time there was no evidence of hemolysis or hemoglobinuria; only on occasion did a small clot form at the tip of the infusion catheter. The infused fatty acids became attached to the circulating albumin and were removed from the plasma and metabolized in the same way as endogenous free fatty acids. There was no evidence to indicate that the infused fatty acids lodged as emboli in the microcirculation or were phagocytized by the reticuloendothelial system. This method makes it possible to study the direct effects of an increased flux of free fatty acids upon such processes as formation and release of triglyceride by the liver, gluconeogenesis, lipogenesis, ketone body production, glucose utilization, and insulin production.

Albumins↗
PubMed1976

Antiarrhythmic effects of arachidonic, linoleic, linolenic, and oleic acid, and the influence of indomethacin and polyphloretinephosphate.

Intravenous application of arachidonic and linoleic acid induced strong antiarrhythmic effects demonstrated on three models of experimental arrhythmias. In contrast, linolenic and oleic acid were poorly effective. The antiarrhythmic action of the unsaturated fatty acids required 10- to 1000-fold higher doses in comparison with the most effective prostaglandins. Indomethacin decreased the antidysrhythmic action of arachidonic and linoleic acid; PG efficiency remained unaffected. Polyphloretinphosphate markedly reduced the improvement of aconitine arrhythmia by PGs, the decrease of the antidysrhythmic effects of arachidonic and linoleic acid was without statistical significance. The results suggest an important role of PG synthesis for the antiarrhythmic effect of polyunsaturated fatty acids.

Aconitine↗
PubMed2004

Laser tweezers Raman study of optically trapped aerosol droplets of seawater and oleic acid reacting with ozone: implications for cloud-droplet properties.

In this communication we report the first use of the Raman laser tweezers technique to trap and hold a mixed droplet of oleic acid and water at atmospheric pressure for 30 min, oxidize the oleic acid on the droplet, follow the decay of reactants and the growth of chemical products using Raman spectroscopy, and monitor the growth in size of the droplet as it becomes more hydrophilic. We demonstrate that the oxidation of organic films on water droplets could have large climatic effects in the atmosphere. We show that cloud-droplet growth and activation of cloud condensation nuclei (to become cloud droplets) is retarded by the presence of an organic film and that chemical oxidation of this film would allow a cloud droplet to grow, reducing cloud albedo by inducing precipitation, and would allow a cloud condensation nucleus to grow to a cloud droplet, thus forming a cloud and increasing the albedo of the Earth.

Journal Article↗
PubMedDate not supplied

Micelles based on polyvinyl alcohol substituted with oleic acid for targeting of lipophilic drugs.

Polymeric micelles based on polyvinyl alcohol substituted with oleic acid were used as vehicles for progesterone and folic acid. The ability of this amphiphilic polymer to entrap lipophilic drugs and to generate stable micelles in aqueous neutral medium makes it a good candidate for drug delivery. The release of the loaded drugs in acidic environments represents another important property of these systems. Size of micelles, their stability, and their drug-loading capacity were evaluated, as well as the in vitro controlled-release profiles at pH 7.4 and 5.5.

Drug Delivery Systems↗
PubMed1991

[Effects of continuous negative extrathoracic pressure ventilation (CNETPV) on gas exchange and hemodynamics in dogs with oleic-acid-induced pulmonary edema].

To investigate usefulness of continuous negative extrathoracic pressure ventilation (CNETPV) as a method of respiratory care for pulmonary edema, we compared effects of CNETPV on gas exchange and hemodynamics with those of CPPV in dogs with oleic-acid-induced pulmonary edema. End-expiratory negative extrathoracic pressure was adjusted to obtain the same increase in functional residual capacity as that obtained with PEEP of 10 cmH2O. Transmural pressure was calculated by subtracting intrapleural pressure from intravascular pressure. Both CNETPV and CPPV improved gas exchange, and changes in PaO2 and venous admixture were similar with two ventilatory modes. During CNETPV, PvO2 and oxygen delivery were significantly greater than those in CPPV. CPPV did not alter transmural filling pressures but decreased cardiac output, whereas CNETPV increased transmural filling pressure and preserved cardiac output. These results indicate that CNETPV can offer comparable improvement in gas exchange with CPPV, when two ventilatory modes are matched for lung volume. In addition, these results suggest that CNETPV may be superior to CPPV because of less depression of cardiac output and greater oxygen delivery to organs.

Animals↗
PubMed2005

Effect of dietary high-oleic-acid oils that are rich in antioxidants on microsomal lipid peroxidation in rats.

In contrast to other metabolic functions, the role of dietary antioxidants and oil on microsomal lipid oxidation has been less extensively studied. This study examines ascorbate-Fe(2+) and NADPH-induced lipid peroxidation of hepatic microsomes of rats that were fed for three weeks high-oleic-acid oils (high-oleic sunflower oil, HOSO; olive oil, OO; or olive pomace oil, OPO) containing different concentrations of the antioxidants alpha-tocopherol, erythrodiol, and oleanolic acid. The fatty acid composition of hepatic microsomes of Wistar rats that were fed for three weeks with the above-mentioned oils had lower proportions of C16:0, C18:2n6, and C22:6n3 and higher proportions of C18:0 and C18:1n9 than rats fed the control diet. Light emission by hepatic microsomes increased, in the first 180 min, 2-fold after ascorbate-Fe(2+) addition compared with NADPH addition. Both increases were less pronounced in microsomes of OPO-fed rats and to a smaller extent in microsomes of OO-fed rats. Smaller increases in light emission were associated positively with higher concentrations of dietary alpha-tocopherol, erythrodiol, and oleanolic acid but were not associated with changes in fatty acid composition of hepatic microsomes. Addition of alpha-tocopherol, erythrodiol, or oleanolic acid decreased light emission of hepatic microsomes with a greater inhibition in microsomes of rats fed the control diet. Our data suggest that erythrodiol and oleanolic acids partly explain the protective effect of dietary OPO on microsomal lipid peroxidation in rats.

Animals↗
PubMed1996

Oleic acid inhibits cholesteryl esterase and cholesterol utilization for testosterone synthesis in mouse Leydig cells.

We have observed that nonesterified fatty acids (NEFA) inhibit testosterone synthesis in response to luteinizing hormone (LH) in mouse Leydig cells, possibly by affecting cholesterol utilization or endogenous concentrations. We have now studied the influence of oleic acid (OA) on the cellular content of cholesterol, hydrolysis of cholesterol esters, and steroidogenesis in isolated mouse Leydig cells. OA (700 micromol/L added with fatty acid-free [FAF] albumin, 3 g/dL) significantly (P<.025) reduced testosterone production in response to LH (10 ng/mL), total cholesterol concentrations of Leydig cells and the culture medium, and cholesteryl esterase activity in the cytosol and mitochondria. We also studied the effects of OA on steroidogenesis and cellular cholesterol concentrations after treatments to increase cellular cholesterol. OA at lower concentrations (5 micromol/L with albumin, 0.1 g/dL) or low-density lipoprotein ([LDL] 4 micrograms protein/mL) increased cellular cholesterol (P<.01) without affecting basal steroidogenesis. These treatments failed to reverse the inhibitory (P<.05) effect of OA on testosterone synthesis following LH stimulation, but did significantly (P<.01) increase cellular cholesterol. In summary, OA appears to inhibit testosterone synthesis by inhibiting cholesteryl esterase activity.

Animals↗