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PubMed2004

Multiphoton polarization and generalized polarization microscopy reveal oleic-acid-induced structural changes in intercellular lipid layers of the skin.

We have demonstrated that both multiphoton polarization and generalized polarization (GP) microscopy may be combined to characterize the structural changes of intercellular lipids in skin. Both polarization and GP (at 440- and 490-nm emission) images obtained by analysis of Laurdan fluorescence suggest that the treatment of oleic acid results in a skin surface with a more random packing of lipid molecules, which allows easier water penetration. Our results show that combined polarization and GP microscopy can be used to characterize the physical and chemical changes in biological structures.

Culture Techniques↗
PubMed1984

Oleic acid promotes the activation and translocation of phosphatidate phosphohydrolase from the cytosol to particulate fractions of isolated rat hepatocytes.

The incubation of hepatocytes with 1-4mM-oleate increased the total activity of phosphatidate phosphohydrolase that was measured in the presence of Mg2+ to about 2-fold. This was accompanied by an increase in the proportion of the enzyme that was isolated with the particulate fractions. Conversely, the addition of up to 4mM-oleate decreased the recovery of phosphatidate phosphohydrolase in the cytosolic fraction from about 70% to 3% when hepatocytes were lysed with digitonin. Most of the increase in the membrane-associated phosphohydrolase activity was isolated after cell fractionation in the microsomal fraction that was enriched with the endoplasmic-reticulum marker arylesterase. It is proposed that the translocation of phosphatidate phosphohydrolase facilitates the increased synthesis of triacylglycerols in the liver when it is presented with an increased supply of fatty acids.

Animals↗
PubMed1993

Is nitric oxide released in oleic acid lung injury?

Inhibitors of endothelium-derived nitric oxide synthesis or activity have been reported to enhance hypoxic vasoconstriction in isolated lung preparations. We hypothesized that methylene blue, a guanylate cyclase inhibitor, and N omega-nitro-L-arginine, a nitric oxide synthase inhibitor, would increase pulmonary vascular tone and improve gas exchange in anesthetized and ventilated (inspired O2 fraction 0.4) dogs with oleic acid (OA) lung injury. Mean pulmonary arterial pressure-(Ppa) flow (Q) relationships (generated by a manipulation of venous return, which was increased by opening a femoral arteriovenous bypass or decreased by inflating an inferior vena cava balloon) and gas exchange (evaluated by arterial blood gases and SF6 intrapulmonary shunt determinations) were investigated before and after OA (0.06 ml/kg i.v.) and again after solvent (n = 8), methylene blue (8 mg/kg i.v., n = 10), or N omega-nitro-L-arginine (40 mg/kg i.v., n = 8) in a randomized order. OA administration induced pulmonary hypertension, decreased arterial PO2, and increased intrapulmonary shunt. After OA, solvent had no effect on pulmonary hemodynamics and gas exchange. Both methylene blue and N omega-nitro-L-arginine further increased Ppa at all levels of Q. Only methylene blue, however, improved gas exchange after OA (arterial PO2 from 71 +/- 6 to 89 +/- 12 Torr and intrapulmonary shunt from 44 +/- 6 to 34 +/- 6%, both P < 0.02). These results suggest that nitric oxide is released during OA lung injury and modulates pulmonary hypertension. Whether nitric oxide impairs the regulation of gas exchange in OA lung injury remains uncertain, however.

Amino Acid Oxidoreductases↗
PubMed2006

Effects of 8-2 fluorotelomer alcohol on oleic acid formation in the liver of rats.

Effects of 8-2 fluorotelomer alcohol on fatty acid composition of lipid in the liver of rats were investigated. Feeding of male rats with a diet that contained 8-2 fluorotelomer alcohol at concentrations of 0.2, 0.4 and 0.8% (w/w) for 14 d caused a significant increase in proportion and content of oleic acid (18 : 1 (n-9)) in the liver. The treatment of rats with 8-2 fluorotelomer alcohol increased activities of palmitoyl-CoA chain elongase (PCE) and stearoyl-CoA desaturase (SCD) and mRNA expressions for rat fatty acid elongase 2 (rELO2) and stearoyl-CoA desaturase 1 (SCD1), but neither rat fatty acid elongase 1 (rELO1) or stearoyl-CoA desaturase 2 (SCD2), in the liver in dose-dependent manners. Multiple regression analyses, which were performed to estimate relative contribution of PCE and SCD for determination of the proportion or the content of 18 : 1 (n-9), revealed that the three parameters were significantly correlated and that standardized partial regression coefficient of PCE was higher than that of SCD. These results suggest that 8-2 fluorotelomer alcohol caused considerable changes in the composition and the content of fatty acid, especially 18 : 1 (n-9), in the liver by inducing PCE and SCD, and that PCE plays a crucial role in the increased proportion of 18 : 1 (n-9) in the liver of the rats given fluorotelomer alcohol.

Animals↗
PubMed2001

Effect of lipids and oleic acid on biomass development in anaerobic fixed-bed reactors. Part I: Biofilm growth and activity.

Two similar anaerobic fixed-bed bioreactors which allowed the biomass to be periodically withdrawn were run in parallel. After feeding each digester with synthetic dairy wastes of different lipid content (Period I), both digesters were fed with increasing sodium oleate concentrations with skim milk as co-substrate (Period II) and oleate as the sole carbon source (Period III). In Period I, the digester fed with lipids was more efficient and exhibited lower levels of volatile fatty acids than the digester fed without lipids. The biofilm built up in the presence of lipids was thinner, but more resistant to the presence of oleate than the biofilm formed in the absence of lipids, which lost 53% of its solids after contacting with oleic acid. The specific methanogenic activity with butyrate as substrate was enhanced in the presence of lipids, but no significant effect was detected on the acetoclastic and hydrogenophilic activities, which remained similar for both digesters along the trial period.

Anaerobiosis↗
PubMed2005

Carbodiimide treatment dramatically potentiates the anticalcific effect of alpha-amino oleic acid on glutaraldehyde-fixed aortic wall tissue.

BACKGROUND: Bifunctional amines were previously found to act as bridging molecules between the terminal ends of incomplete glutaraldehyde (GA) cross-links. The additional cross-links thus formed between -NH2 groups of tissue were seen to significantly inhibit bioprosthetic calcification. In the current study, the potential ability of alpha-amino oleic acid (AOA) to act as a bridging molecule between -NH2- and COOH-dependent cross-links was hypothesized to similarly augment the anticalcification effect of the AOA molecule. METHODS: Porcine aortic wall tissue from Medtronic Freestyle valve bioprostheses incorporating the AOA anticalcification process additionally underwent carboxyl-group cross-linking with Jeffamine (poly[propylene glyco]-bis-[aminopropyl ether]) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). Tissue was subdermally implanted into 5-week-old Long-Evans rats for 60 days. Standard 0.2% GA-fixed tissue served as a control. To further assess the impact of storage solution on AOA tissue, samples were either stored in GA (0.2%GA) or EDC (25 mmol/L carbodiimide) before implantation. Tissue calcification was assessed by atomic absorption spectroscopy and histochemical staining. RESULTS: Aldehyde end-capping with AOA achieved only a modest reduction of calcification in GA-treated aortic wall tissue (-20.0%; p < 0.05). Replacing GA with EDC as a storage solution led to a further 32.4% (p < 0.01) mitigation of calcification in Freestyle tissue. Incorporating an intermediate EDC/Jeffamine cross-linking step achieved a distinct additional reduction of calcification by 40.4% (p < 0.05). Overall, aortic wall calcification was 59.7% (p < 0.0001) lower if commercial Freestyle tissue underwent an additional EDC/Jeffamine cross-linking step and subsequent storage in EDC. Relative to control GA-fixed tissue, this represented a 67.8% (p < 0.0001) reduction. Incorporation of AOA was essential for the beneficial effect of the additional EDC/Jeffamine cross-linking step. CONCLUSIONS: Potentially utilizing both the amino- and the carboxyl moieties of AOA for tissue binding dramatically reduces aortic wall calcification of GA-fixed tissue.

Animals↗
PubMed2005

The effect of trans sodium crocetinate (TSC) in a rat oleic acid model of acute lung injury.

Trans sodium crocetinate is a novel drug, which has been shown previously to increase whole-body oxygen consumption during hemorrhagic shock. TSC has been suggested to work by increasing the diffusion rate of oxygen through plasma rather than on a specific symptom of hemorrhagic shock and has been suggested as a general treatment for hypoxemia. Thus, it might also be beneficial for treating respiratory insufficiencies. This study employed an oleic acid model of acute lung injury to determine if TSC could increase arterial PO2 in that model.

Animals↗
PubMed1989

Abnormalities of pathways of fibrin turnover in lung lavage of rats with oleic acid and bleomycin-induced lung injury support alveolar fibrin deposition.

Alveolar fibrin deposition commonly accompanies acute lung injury, but the nature of the local abnormalities of coagulation and fibrinolysis that support pathologic fibrin deposition are not well understood. The trended abnormalities of procoagulant and fibrinolytic activities occurring in lung lavage fluids of Fischer 344 rats after lung injury induced by intravenous oleic acid (OA) or intratracheal bleomycin were studied. After injury by either agent, bronchoalveolar lavage (BAL) contained increased procoagulant activity and decreased fibrinolytic activity. Lavage procoagulant activity was mainly due to an activator of Factor X attributable to the extrinsic coagulation pathway, and fibrinolytic activity was almost completely plasminogen dependent. Major mechanisms of inhibition of fibrinolytic activity involved both the inhibition of the plasminogen activator (PA) and plasmin. These abnormalities were temporally associated with prominent alveolar fibrin deposition in both models. In OA-treated animals, lavage fibrinolytic activity was absent or profoundly decreased, and antiplasmin and procoagulant activities were increased within 4 hours after the induction of acute lung injury. By 24 hours after OA, lavage PA inhibitor (PAI) activity was elevated with sustained antiplasmin activity. By 3 days after OA, these abnormalities had resolved in association with almost complete resolution of alveolar fibrin deposits. Within 3 days after bleomycin-induced lung injury, lavage procoagulant activity was increased and fibrinolytic activity was depressed due to increased antiplasmin and PAI activities. These conditions persisted for 2 weeks, during which time alveolar fibrin deposition was associated with the development of pulmonary fibrosis. These data indicate that a disruption of the normal balance between procoagulant and fibrinolytic activities occurs in alveolar lining fluids of rats with alveolitis induced by either OA or bleomycin, and that concurrent abnormalities of pathways of fibrin turnover that occur in alveolar lining fluids promote the alveolar fibrin deposition associated with these lung injuries.

Animals↗
PubMed1999

Yeast peroxisomal multifunctional enzyme: (3R)-hydroxyacyl-CoA dehydrogenase domains A and B are required for optimal growth on oleic acid.

The yeast peroxisomal (3R)-hydroxyacyl-CoA dehydrogenase/2-enoyl-CoA hydratase 2 (multifunctional enzyme type 2; MFE-2) has two N-terminal domains belonging to the short chain alcohol dehydrogenase/reductase superfamily. To investigate the physiological roles of these domains, here called A and B, Saccharomyces cerevisiae fox-2 cells (devoid of Sc MFE-2) were taken as a model system. Gly(16) and Gly(329) of the S. cerevisiae A and B domains, corresponding to Gly(16), which is mutated in the human MFE-2 deficiency, were mutated to serine and cloned into the yeast expression plasmid pYE352. In oleic acid medium, fox-2 cells transformed with pYE352:: ScMFE-2(aDelta) and pYE352::ScMFE-2(bDelta) grew slower than cells transformed with pYE352::ScMFE-2, whereas cells transformed with pYE352::ScMFE-2(aDeltabDelta) failed to grow. Candida tropicalis MFE-2 with a deleted hydratase 2 domain (Ct MFE- 2(h2Delta)) and mutational variants of the A and B domains (Ct MFE- 2(h2DeltaaDelta), Ct MFE- 2(h2DeltabDelta), and Ct MFE- 2(h2DeltaaDeltabDelta)) were overexpressed and characterized. All proteins were dimers with similar secondary structure elements. Both wild type domains were enzymatically active, with the B domain showing the highest activity with short chain and the A domain with medium and long chain (3R)-hydroxyacyl-CoA substrates. The data show that the dehydrogenase domains of yeast MFE-2 have different substrate specificities required to allow the yeast to propagate optimally on fatty acids as the carbon source.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1977

Histamine release in dogs by Cremophor E1 and its derivatives: oxethylated oleic acid is the most effective constituent.

Several preparations of Cremophor E1, several of other non-ionic detergents and several components of Cremophor E1 were tested for their histamine-releasing capacity in dogs. Lutensol AP 10 and a derivative of 1,2-propylenglycol were ineffective, but showed excellent properties as detergents. Thus the histamine-releasing capacity was not necessarily combined with the tenside effect of the surfactants. Oleic acid found in Tween 80 as well as in Cremophor E1 seems to be the most effective constituent, but the alcohol seems also to be important for the histamine-releasing capacity. The development of a non-toxic solubilizer for lipophilic drugs seems of considerable clinical interest.

Animals↗
PubMed2005

Relationship among cardiac index, inspiration/expiration ratio, and perfluorocarbon dose during partial liquid ventilation in an oleic acid model of acute lung injury in sheep.

BACKGROUND: The aim of this study was to demonstrate the influence of different inspiration/expiration (I/E) ratios on cardiac index (CI) and hemodynamics during partial liquid ventilation (PLV) using a large animal model of acute respiratory failure in a prospective, randomized controlled animal laboratory trial. METHODS: After induction of respiratory failure by right atrial injection of 0.09 mL/kg oleic acid, (1) determination of agreement between reversed Fick and pulmonary artery thermodilution (QTD) techniques with progressive doses of perflubron (LiquiVent, Alliance Pharmaceutical Corp, San Diego, Calif) (n = 7 sheep) and (2) comparison of 4 groups with I/E ratios of 3.4:1, 2:1, 1:1, and 1:2 were performed, applying identical ventilatory patterns in all I/E groups (n = 28 sheep). PLV was established with intratracheal instillation of 25 mL/kg perflubron. Cardiac index was assessed at 15-minute intervals for a 120-minute experimental period by QTD. RESULTS: During progressive doses of PLV, the correlation (r) between Fick and QTD techniques was 0.82. Thermodilution deteriorated after induction of lung injury and recovered after PLV start. Regarding QTD, no significant changes after PLV onset (within-group comparison) and between I/E groups were observed (P < .05). CONCLUSION: The QTD technique is a satisfactory reflector of CI during PLV, and I/E ratio has no significant influence on CI, even using extreme inverse ratio ventilation.

Animals↗
PubMed1998

Treatment of pulmonary hypertension and hypoxia due to oleic acid induced lung injury with intratracheal prostaglandin E1 during partial liquid ventilation.

BACKGROUND: Partial liquid ventilation using perfluorocarbon liquids may be of therapeutic benefit in patients with acute respiratory failure. This study investigated the effects of prostaglandin E1 (PGE1) delivered intratracheally during partial liquid ventilation on lung function and pulmonary circulation in rabbits with acute respiratory distress syndrome. METHODS: Lung injury was induced by intravenous oleic acid in adult Japanese white rabbits, 1 h after which they were divided into four groups of 10 animals. Group 1 received mechanical ventilation alone, group 2 received aerosolized PGE1 (5 microg followed by 0.1 microg x kg(-1) x min(-1)) under mechanical ventilation combined with 5 cm H2O positive end-expiratory pressure, and groups 3 and 4 received partial liquid ventilation with 15 ml/kg perflubron. Group 4 received a 5-microg bolus followed by 0.1 microg x kg(-1) x min(-1) PGE1 instilled intratracheally (not by aerosol) in combination with partial liquid ventilation. Measurements were performed at 30-min intervals for 120 min after lung injury. RESULTS: After lung injury, hypoxemia, hypercapnia, acidosis, and pulmonary hypertension developed in all animals and were sustained in groups 1 and 2 throughout the experiment. The partial pressure of oxygen in arterial blood of animals in group 3 improved with initiation of treatment, with statistical significance achieved at the 30 and 60 min time points as compared with controls. Group 4 animals had immediate and sustained increases in the partial pressure of oxygen in arterial blood that were significant compared with all other groups during the experiment. Statistically significant reductions in mean pulmonary artery pressure were seen only in group 4 animals compared with all other groups. CONCLUSIONS: These results suggest that PGE1 delivered intratracheally during partial liquid ventilation may be a useful therapeutic strategy for patients with the acute respiratory distress syndrome.

Animals↗
PubMed1975

Pulmonary insufficiency induced by oleic acid in the sheep: a model for investigation of extracorporeal oxygenation.

Most previous studies of the efficiency of bypass techniques for respiratory support have been conducted in hypoxic but otherwise normal animals. However, mechanisms of improved oxygenation by partial venoarterial bypass in the presence of acute respiratory insufficiency can be better studied with an appropriate pathophysiologic model; for this purpose, acute hemorrhagic pulmonary edema was induced in sheep by injection of oleic acid into the right atrium. The model presented a 3 hour period of elevated pulmonary shunting with stable hemodynamics. This preparation is being employed to the study of the mechanisms of extracorporeal oxygenation.

Animals↗
PubMed1998

The combination of partial liquid ventilation and inhaled nitric oxide in the severe oleic acid lung injury model.

STUDY OBJECTIVES: To elucidate the efficacy of the combination of inhaled nitric oxide (NO) and partial liquid ventilation (PLV) in ARDS. DESIGN: Prospective, randomized, controlled study. SETTING: A research laboratory at a university medical center. SUBJECTS: Thirty-two rabbits. INTERVENTIONS: Animals were anesthetized and ventilated via tracheostomy (tidal volume=40 mL; respiratory rate=25 breaths/min; fraction of inspired oxygen=0.99). After 0.08 mL/kg (0.071 g/kg) oleic acid was administered via the central venous route, animals were randomly divided into the following four groups depending on the ventilatory mode: (1) Gas ventilation (GV)-control group: GV was continued throughout the study; (2) GV-NO group: NO inhalation (10 ppm) was performed under GV; (3) PLV-control group: PLV using perflubron (15 mL/kg) was continued until the end of the study; and (4) PLV-NO group: NO inhalation (10 ppm) was performed under PLV. MEASUREMENTS AND RESULTS: NO inhalation improved PaO2 in the PLV-NO group (from 133+/-20 to 167+/-23 mm Hg; p=0.0008), but not in the GV-NO group (from 67+/-6 to 63+/-9 mm Hg), although pulmonary vascular resistance decreased both in the GV-NO (from 4,604+/-328 to 4,337+/-322 dyne x s x cm(-5); p=0.0116) and the PLV-NO group (from 4,727+/-665 to 4,112+/-560 dyne x s x cm(-5); p=0.0036). (Data were expressed as mean+/-SEM.) CONCLUSION: PLV augmented the effect of inhaled NO on pulmonary gas exchange. The combination of PLV and NO inhalation could be effective in severe ARDS.

Animals↗
PubMed1983

Mechanisms of physiological dead space response to PEEP after acute oleic acid lung injury.

In acute increased-permeability edema, the Bohr physiological dead space (VD/VTCO2) can be influenced by changes in anatomic dead space, ventilation-perfusion (VA/Q) heterogeneity, shunt, and the Haldane effect. We used the multiple inert gas elimination technique to assess the effect of positive end-expiratory pressure (PEEP) on each of these components of VD/VTCO2 in 14 pentobarbital-anesthetized dogs with increased permeability edema induced by infused oleic acid. PEEP of 5, 10, 15, and 20 cmH2O was applied in random sequence. Following injury VD/VTCO2 increased. It decreased with 5 or 10 cmH2O PEEP but increased progressively at higher PEEP levels. The decrease in VD/VTCO2 at 5 or 10 cmH2O PEEP was due to reductions in shunt and midrange VA/Q heterogeneity. The increase in VD/VTCO2 that occurred with higher PEEP levels was due to increased ventilation to high VA/Q regions and a larger anatomic dead space. Haldane effect magnified the shunt component of VD/VTCO2 but reduced the influence of midrange VA/Q heterogeneity.

Acute Disease↗
PubMed2000

Characterization of oleic acid and propranolol oleate mesomorphism using (13)C solid-state nuclear magnetic resonance spectroscopy (SSNMR).

Lipids regularly exhibit complicated thermotropic and lyotropic phase behavior. In this study, the utility of (13)C solid-state nuclear magnetic resonance spectroscopy (SSNMR) in characterizing the phase properties of pharmaceutical lipids was investigated. Variable temperature (13)C SSNMR spectra and spin-lattice relaxation times (T(1)(C)) were obtained for high-purity oleic acid (OA) and propranolol oleate (POA). Spectral changes took place following OA gamma-to-alpha phase transition that indicated increased nuclear inequivalence of aliphatic chain carbons in the alpha phase. T(1)(C) data for the alpha phase demonstrated considerable conformational changes throughout the aliphatic chain, not solely in the methyl side chain as previously reported. These data support alpha-OA classification as a conformationally disordered crystalline phase. The prevalence of low T(1)(C) values in both POA I and II suggested the absence of a rigid crystalline molecular lattice, so both phases were described as conformationally disordered crystalline phases. A two-phase mixture of POA I and II was also identified, emphasizing the sensitivity of this technique. (13)C SSNMR provided valuable information regarding the nuclear environment of specific functional groups in lipid crystalline and mesomorphic structures. Understanding phase behavior at the molecular level can aid selection of appropriate formulation strategies for lipids by allowing prediction of processing properties, and physical and chemical stability. (13)C SSNMR is a powerful technique for pharmaceutical lipid characterization.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Effects of oleic acid on murine CD4+ T cell death and anti-CD3 or superantigen induced proliferation at low temperature.

Studies were conducted to examine the effects of low, yet physiologically relevant, temperatures on murine T lymphocyte responses. Akin to ectothermic vertebrate responses, lectin-induced murine T cell proliferation was previously shown to be ablated at temperatures 10 degrees C below optimal (i.e. 27 degrees C); responsiveness at 27 degrees C was restored by the addition of oleic acid (18:1). The aim of the present study was to address the mechanism involved in such low temperature suppression. Murine splenic CD4+ T lymphocytes stimulated with either alpha CD3 or SEB exhibited cell death, as opposed to anergy, at 27 degrees C. However proliferation was observed in the presence of 18:1. Thus low temperature-suppression of murine CD4+ T cells is also mediated through TCR and/or CD3 pathways. Additional studies examining the temporal effects of adding 18:1, as well as temperature shifts, indicated that the cell death induced by stimulation at low temperature was preventable by 18:1.

Animals↗