Ethyl Arachidonate

Fatty acid ethyl esters in meconium and substance use in adolescence.[Pubmed:33340653]

Neurotoxicol Teratol. 2021 Jan-Feb;83:106946.

Prenatal alcohol exposure (PAE) continues to be a serious public health problem, yet no reliable clinical tools are available for assessing levels of drinking during pregnancy. Fatty acid ethyl esters (FAEEs), the nonoxidative metabolites of ethanol measured in meconium, are potential biomarkers to quantify the level of PAE. The association between the concentrations of FAEEs from meconium and adolescent substance use and related problems was examined in a prospective birth-cohort of adolescents exposed to alcohol and drugs in utero. FAEEs were quantified with gas chromatography via a flame ionization detector. Meconium was analyzed for FAEEs in 216 newborns; 183 of them (81 boys, 102 girls) were assessed at age 15 for alcohol, tobacco, and marijuana use using biologic assays and self-report. Substance use problems were assessed using the Problem Oriented Screening Instrument for Teenagers. Findings from multivariable logistic regression analyses indicated that, after controlling for other prenatal drug exposure and covariates, higher concentrations of FAEEs (ethyl myristate, ethyl palmitate, ethyl oleate, ethyl linoleate, ethyl linolenate, and Ethyl Arachidonate) were related to a greater likelihood of marijuana use and experiencing substance use problems, but not tobacco or alcohol use, at age 15. Elevated levels of FAEEs in meconium may be promising markers for PAE, identifying newborns at risk for early substance use and developing substance use problems.

Efficient determination of six fatty acid ethyl ethers in human whole blood by gas chromatography-mass spectrometry.[Pubmed:28755750]

Alcohol. 2017 Aug;62:41-47.

Fatty acid ethyl esters (FAEEs) have been widely studied as specific markers of ethanol intake and mediators of ethanol-induced diseases. In the present study, a simple and rapid gas chromatography-mass spectrometry (GC-MS) method was established for the qualitative and quantitative analysis of six fatty acid ethyl esters (FAEEs), including ethyl myristate, ethyl palmitate, ethyl stearate, ethyl oleate, ethyl linoleate, and Ethyl Arachidonate, in human whole blood. FAEEs were extracted from 200 muL of human whole blood by a modified liquid-liquid extraction, and the hexane layer was injected directly into GC-MS with ethyl heptadecanoate as the internal standard. The limits of detection (LODs) and limits of quantification (LOQs) were in the range of 5-50 ng/mL and 15-200 ng/mL, respectively. Linearity ranged up to 10 mug/mL with r(2) higher than 0.998. Accuracy was in the range of 90.3-109.7%, while intra-day and inter-day precision were 0.7-9.3% and 3.4-12.5%, respectively. This method was then applied to 38 real samples from forensic cases. Differences in the most common FAEEs between Chinese and Western subjects were discussed. The relationship of FAEE concentrations with age and gender was also investigated.

Kinetic Study of the Aroxyl-Radical-Scavenging Activity of Five Fatty Acid Esters and Six Carotenoids in Toluene Solution: Structure-Activity Relationship for the Hydrogen Abstraction Reaction.[Pubmed:28737395]

J Phys Chem B. 2017 Aug 17;121(32):7593-7601.

A kinetic study of the reaction between an aroxyl radical (ArO(*)) and fatty acid esters (LHs 1-5, ethyl stearate 1, ethyl oleate 2, ethyl linoleate 3, ethyl linolenate 4, and Ethyl Arachidonate 5) has been undertaken. The second-order rate constants (k(s)) for the reaction of ArO(*) with LHs 1-5 in toluene at 25.0 degrees C have been determined spectrophotometrically. The k(s) values obtained increased in the order of LH 1 < 2 < 3 < 4 < 5, that is, with increasing the number of double bonds included in LHs 1-5. The k(s) value for LH 5 was 2.93 x 10(-3) M(-1) s(-1). From the result, it has been clarified that the reaction of ArO(*) with LHs 1-5 was explained by an allylic hydrogen abstraction reaction. A similar kinetic study was performed for the reaction of ArO(*) with six carotenoids (Car-Hs 1-6, astaxanthin 1, beta-carotene 2, lycopene 3, capsanthin 4, zeaxanthin 5, and lutein 6). The k(s) values obtained increased in the order of Car-H 1 < 2 < 3 < 4 < 5 < 6. The k(s) value for Car-H 6 was 8.4 x 10(-4) M(-1) s(-1). The k(s) values obtained for Car-Hs 1-6 are in the same order as that of the values for LHs 1-5. The results of detailed analyses of the k(s) values for the above reaction indicated that the reaction was also explained by an allylic hydrogen abstraction reaction. Furthermore, the structure-activity relationship for the reaction was discussed by taking the result of density functional theory calculation reported by Martinez and Barbosa into account.

Flavonoids with potent antioxidant activity found in young green barley leaves.[Pubmed:22681491]

J Agric Food Chem. 2012 Jun 27;60(25):6260-7.

Saponarin, a flavonoid found in young green barley leaves, possesses potent antioxidant activities, which are determined by its inhibition of malonaldehyde (MA) formation from various lipids oxidized by UV light or Fenton's reagent. Lipids used were squalene, ethyl linoleate, ethyl linolenate, Ethyl Arachidonate, octadecatetraenoic acid (ODTA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), cod liver oil, lecithin I, lecithin II, and blood plasma. The addition of saponarin inhibited the formation of MA from squalene upon UV irradiation at the level of 2 mumol/mL by almost 100%, whereas BHT inhibited its formation by 75% at the same level. Saponarin showed potent antioxidant activity toward fatty acid ethyl esters at levels >100 mug/mL. Saponarin inhibited MA formation in ODTA by 60%, in EPA by 50%, and in DHA by 43% at the level of 15 mumol/mL. Saponarin exhibited strong antioxidant activities with dose-response levels toward cod liver oil and lipoproteins (lecithins I and II), higher than those of alpha-tocopherol. A mixture of saponarin/lutonarin (4.5:1, w/w) inhibited MA formation appreciably from all lipids tested with dose response. This mixture exhibited highest effect toward cod liver oil (86%), followed by DHA, lecithin II, blood plasma, EPA, and lecithin I. Supplementation of young green barley leaves containing saponarin should be beneficial to health and may prevent diseases caused by oxidative damage such as various cancers, inflammations, and cardiovascular diseases.

Metabonomic investigation of liver profiles of nonpolar metabolites obtained from alcohol-dosed rats and mice using high mass accuracy MSn analysis.[Pubmed:21028815]

J Proteome Res. 2011 Feb 4;10(2):705-13.

Alcoholism is a complex disorder that, in man, appears to be genetically influenced, although the underlying genes and molecular pathways are not completely known. Here, the intragastric alcohol feeding model in rodents was used together with high mass accuracy LC-MS(n) analysis to assess the metabonomic changes in nonpolar metabolite profiles for livers from control and alcohol-treated rats and mice. Ion signals with a peak area variance of less than 30% (based on repeat analysis of a pooled quality control sample analyzed throughout the batch) were submitted to multivariate statistical analysis (using principal components analysis, PCA). PCA revealed robust differences between profiles from control and alcohol-treated animals from both species. The major metabolites seen to differ between control and alcohol-treated animals were identified using high accuracy MS(n) data and verified using external search engines ( http://www.lipidmaps.org ; http://www.hmdb.ca; http://www.genome.jp/kegg/ ) and authentic standards. The main metabolite classes to show major changes in the alcoholic liver-derived samples were fatty acyls, fatty acid ethyl esters, glycerolipids, and phosphatidylethanol homologues. Significant metabolites that were up-regulated by alcohol treatment in both rat and mouse livers included fatty acyls, metabolites such as octadecatrienoic acid and eicosapentaenoic acid, a number of fatty acid ethyl esters such as Ethyl Arachidonate, ethyl docosahexaenoic acid, ethyl linoleate, and ethyl oleate and phosphatidylethanol (PEth) homologues (predominantly PEth 18:0/18:2 and PEth 16:0/18:2; PEth homologues are currently considered as potential biomarkers for harmful and prolonged alcohol consumption in man). A number of glycerophospholipids resulted in both up-regulation (m/z 903.7436 [M + H](+) corresponding to a triglyceride) and down-regulation (m/z 667.5296 [M + H](+) corresponding to a diglyceride). Metabolite profiles were broadly similar in both mouse and rat models. However, there were a number of significant differences in the alcohol-treated group particularly in the marked down-regulation of retinol and free cholesterol in the mouse compared to the rat. Unique markers for alcohol treatment included ethyl docosahexaenoic acid. Metabolites were identified with high confidence using predominantly negative ion MS(n) data for the fatty acyl components to match to www.lipidmaps.org MS and MS/MS databases; interpreting positive ion data needed to take into account possible adduct ions which may confound the identification of other lipid classes. The observed changes in lipid profiles were consistent with alcohol-induced liver injury in humans.

Quantitation of fatty acid ethyl esters in human meconium by an improved liquid chromatography/tandem mass spectrometry.[Pubmed:20605750]

J Chromatogr B Analyt Technol Biomed Life Sci. 2010 Jul 1;878(21):1871-4.

This paper reports the development and validation of an improved assay for quantitation of fatty acid ethyl esters (FAEEs) in human meconium using liquid chromatography/tandem mass spectrometry (LC-MS/MS). FAAEs (ethyl laurate, ethyl myristate, ethyl palmitate, ethyl palmitoleate, ethyl stearate, ethyl oleate, ethyl linoleate, ethyl linolenate, and Ethyl Arachidonate) and the internal standard (I.S.), ethyl heptadecanoate, were separated by reverse phase HPLC and quantified by MS/MS using electrospray ionization (ESI) and multiple reaction monitoring (MRM) in the positive ionization mode. The absolute recovery of FAEEs varied from 55+/-10% for 0.33 nmol/g (100 ng/g) of ethyl linoleate up to 86+/-8% for 1.55 nmol/g (500 ng/g) of ethyl miristate. The LODs and LOQs varied from 0.01 to 0.08 nmol/g and from 0.02 to 0.27 nmol/g, respectively. The assay has been successfully applied to examine the FAEE levels in 81 meconium samples from babies born to mothers reporting alcohol consumption, to varying degrees, during pregnancy.

Determination of eight fatty acid ethyl esters in meconium samples by headspace solid-phase microextraction and gas chromatography-mass spectrometry.[Pubmed:20549668]

J Sep Sci. 2010 Jul;33(14):2115-22.

A number of fatty acid ethyl esters (FAEEs) have recently been detected in meconium samples. Several of these FAEEs have been evaluated as possible biomarkers for in utero ethanol exposure. In the present study, a method was optimized and validated for the simultaneous determination of eight FAEEs (ethyl laurate, ethyl myristate, ethyl palmitate, ethyl palmitoleate, ethyl stearate, ethyl oleate, ethyl linoleate and Ethyl Arachidonate) in meconium samples. FAEEs were extracted by headspace solid-phase microextraction. Analyte detection and quantification were carried out using GC-MS operated in chemical ionization mode. The corresponding D5-ethyl esters were synthesized and used as internal standards. The LOQ and LOD for each analyte were <150 and <100 ng/g, respectively. The method showed good linearity (r(2)>0.98) in the concentration range studied (LOQ-2000 ng/g). The intra- and interday imprecision, given by the RSD of the method, was lower than 15% for all FAEEs studied. The validated method was applied to 63 authentic specimens. FAEEs could be detected in alcohol-exposed newborns (>600 ng/g cumulative concentration). Interestingly, FAEEs could also be detected in some non-exposed newborns, although the concentrations were much lower than those measured in exposed cases.

Kinetic study of the prooxidant effect of alpha-tocopherol. Hydrogen abstraction from lipids by alpha-tocopheroxyl radical.[Pubmed:19763654]

Lipids. 2009 Oct;44(10):935-43.

A kinetic study of the prooxidant effect of alpha-tocopherol was performed. The rates of allylic hydrogen abstraction from various unsaturated fatty acid esters (ethyl stearate 1, ethyl oleate 2, ethyl linoleate 3, ethyl linolenate 4, and Ethyl Arachidonate 5) by alpha-tocopheroxyl radical in toluene were determined, using a double-mixing stopped-flow spectrophotometer. The second-order rate constants (k (p)) obtained are <1 x 10(-2) M(-1 )s(-1) for 1, 1.90 x 10(-2) M(-1 )s(-1) for 2, 8.33 x 10(-2 )M(-1 )s(-1) for 3, 1.92 x 10(-1) M(-1 )s(-1) for 4, and 2.43 x 10(-1 )M(-1 )s(-1) for 5 at 25.0 degrees C. Fatty acid esters 3, 4, and 5 contain two, four, and six -CH(2)- hydrogen atoms activated by two pi-electron systems (-C=C-CH(2)-C=C-). On the other hand, fatty acid ester 2 has four -CH(2)- hydrogen atoms activated by a single pi-electron system (-CH(2)-C=C-CH(2)-). Thus, the rate constants, k (abstr)/H, given on an available hydrogen basis are k (p)/4 = 4.75 x 10(-3 )M(-1 )s(-1) for 2, k (p)/2 = 4.16 x 10(-2) M(-1 )s(-1) for 3, k (p)/4 = 4.79 x 10(-2 )M(-1 )s(-1) for 4, and k (p)/6 = 4.05 x 10(-2 )M(-1 )s(-1) for 5. The k (abstr)/H values obtained for 3, 4, and 5 are similar to each other, and are by about one order of magnitude higher than that for 2. From these results, it is suggested that the prooxidant effect of alpha-tocopherol in edible oils, fats, and low-density lipoproteins may be induced by the above hydrogen abstraction reaction.

Nitrogen substituent polarity influences dithiocarbamate-mediated lipid oxidation, nerve copper accumulation, and myelin injury.[Pubmed:19093748]

Chem Res Toxicol. 2009 Jan;22(1):218-26.

Dithiocarbamates have a wide spectrum of applications in industry, agriculture, and medicine, with new applications being investigated. Past studies have suggested that the neurotoxicity of some dithiocarbamates may result from copper accumulation, protein oxidative damage, and lipid oxidation. The polarity of a dithiocarbamate's nitrogen substituents influences the lipophilicity of the copper complexes that it generates and thus potentially determines its ability to promote copper accumulation within nerve and induce myelin injury. In the current study, a series of dithiocarbamate-copper complexes differing in their lipophilicity were evaluated for their relative abilities to promote lipid peroxidation determined by malondialdehyde levels generated in an Ethyl Arachidonate oil-in-water emulsion. In a second component of this study, rats were exposed to either N,N-diethyldithiocarbamate or sarcosine dithiocarbamate; both generated dithiocarbamate-copper complexes that were lipid- and water-soluble, respectively. Following the exposures, brain, tibial nerve, spinal cord, and liver tissue copper levels were measured by inductively coupled mass spectroscopy to assess the relative abilities of these two dithiocarbamates to promote copper accumulation. Peripheral nerve injury was evaluated using grip strengths, nerve conduction velocities, and morphologic changes at the light microscope level. Additionally, the protein expression levels of glutathione transferase alpha and heme-oxygenase-1 in nerve were determined, and the quantity of protein carbonyls was measured to assess levels of oxidative stress and injury. The data provided evidence that dithiocarbamate-copper complexes are redox active and that the ability of dithiocarbamate complexes to promote lipid peroxidation is correlated to the lipophilicity of the complex. Consistent with neurotoxicity requiring the formation of a lipid-soluble copper complex, significant increases in copper accumulation, oxidative stress, and myelin injury were produced by N,N-diethyldithiocarbamate but not by sarcosine dithiocarbamate.

Liquid chromatography-tandem mass spectrometry for fatty acid ethyl esters in meconium: assessment of prenatal exposure to alcohol in two European cohorts.[Pubmed:18786798]

J Pharm Biomed Anal. 2008 Nov 4;48(3):927-33.

Fatty acid ethyl esters (FAEEs) in meconium emerged as a reliable, direct biological marker for establishing fetal exposure to ethanol. We developed an LC-MS/MS method for ethyl laurate, ethyl myristate, ethyl palmitate, ethyl palmitoleate, ethyl stearate, ethyl oleate, ethyl linoleate, ethyl linolenate, and Ethyl Arachidonate using ethyl heptadecanoate as the internal standard. The analytes were extracted from meconium with hexane, followed by solid-phase extraction with aminopropyl-silica columns. Chromatography was performed on a C(8) reversed-phase column using water/isopropanol/acetonitrile (20:40:40, v/v/v) as a mobile phase. A triple quadrupole mass spectrometer that monitored the transitions in multiple reaction-monitoring mode was used for the detection of the analytes. Limits of quantification (LOQs) varied between 0.12 and 0.20 nmol/g. Calibration curves were linear from LOQs to 50 nmol/g for all analytes, with a minimum r(2)>0.99. At three concentrations spanning the linear dynamic range, mean recoveries ranged between 53.6 and 86.7% for the different analytes. The validated method was applied to analysis of meconium in newborns of two European cities. The two cohorts presented with different prevalence of gestational ethanol consumption during pregnancy.

The cannabinoid receptor agonist CP-55,940 and ethyl arachidonate interfere with [(3)H]batrachotoxinin A 20 alpha-benzoate binding to sodium channels and inhibit sodium channel function.[Pubmed:18599378]

Comp Biochem Physiol C Toxicol Pharmacol. 2008 Sep;148(3):244-9.

Recent investigations in our laboratory showed that voltage-gated sodium channels (VGSCs) in brain are sensitive to inhibition by various synthetic cannabinoids and endocannabinoids. The present experiments examined the effects of the cannabinoid-1 (CB1) receptor agonist CP-55,940 and Ethyl Arachidonate on [(3)H]batrachotoxinin A 20 alpha-benzoate ([(3)H]BTX-B]) binding and VGSC-dependent depolarization of the nerve membrane in synaptoneurosomes isolated from mouse whole brain. CP-55,940 acted as a full inhibitor of [(3)H]BTX-B binding and its IC(50) was established at 22.3 microM. At its maximum effect concentration, Ethyl Arachidonate achieved partial (approximately 70%) inhibition and was less effective than CP-55,940 as an inhibitor of binding (IC(50)=262.7 microM). The potent CB1 receptor antagonist AM251 (2 microM) had no significant effect on the displacement of [(3)H]BTX-B by either compound (P>0.05). Scatchard analyses showed that CP-55,940 and Ethyl Arachidonate reduce the binding of [(3)H]BTX-B by lowering its B(max) but Ethyl Arachidonate also increased the K(d) of radioligand binding. In kinetic experiments, CP-55,940 and Ethyl Arachidonate were found to boost the dissociation of [(3)H]BTX-B from VGSCs to rates that exceed the maximum velocity achievable by veratridine, indicating they operate as allosteric inhibitors of [(3)H]BTX-B binding. Neither compound was effective at changing the initial rate of association of [(3)H]BTX-B with sodium channels. CP-55,940 and Ethyl Arachidonate inhibited veratridine-dependent (TTX-suppressible) depolarization of the plasma membrane of synaptoneurosomes with IC(50)s of 3.2 and 50.1 microM respectively. These inhibitory effects were again not influenced by 2 microM AM251. Our data demonstrate that the potent cannabinoid receptor agonist CP-55,940 and the ethyl ester of arachidonic acid have the ability to associate with VGSCs and inhibit their function independently of effects on CB1 receptors. Binding data comparisons using mouse brain preparations indicate CP-55,940 is approximately 10,000 times more potent as a CB1 receptor ligand than a sodium channel ligand while Ethyl Arachidonate shows a much smaller differential. Ethyl Arachidonate has been shown previously to be the principal metabolite of ethanol in the brains of intoxicated individuals and effects of this ester on VGSCs and CB1 receptors may contribute to the depressant effects of alcohol.

Fatty acid ethyl esters in meconium are associated with poorer neurodevelopmental outcomes to two years of age.[Pubmed:18492517]

J Pediatr. 2008 Jun;152(6):788-92.

OBJECTIVE: To determine the relationship between fatty acid ethyl esters (FAEE) in meconium and neurodevelopment in infants exposed to alcohol in utero at 6.5 months, 1 year, and 2 years of age. STUDY DESIGN: A secondary analysis of a prospective cohort of mothers at high risk and their infants recruited after admission to a labor and delivery unit. Mothers were screened for drug and alcohol use during pregnancy by clinical interview and urine screening. Meconium was analyzed for FAEE in 216 newborn infants. Outcome measures included the Bayley Scales of Infant Development Mental (MDI) and Psychomotor (PDI) Developmental Index scores in infants at 6.5 months, 1 year, and 2 years of age. RESULTS: After controlling for prenatal visits and maternal factors, increasing concentrations of FAEE were significantly associated with poorer mental and psychomotor development (beta +/- standard error) at all follow-up visits: ethyl myristate (MDI -2.46 +/- 1.24, P = .05; PDI -3.88 +/- 1.67, P = .02), ethyl oleate (MDI -1.94 +/- 0.65, P < .01; PDI -2.60 +/- 0.93, P < .01), ethyl linoleate (MDI -1.92 +/- 0.60, P < .01; PDI -2.28 +/- 0.84, P < .01), ethyl linolenate (MDI -1.99 +/- 0.74, P < .01; PDI -2.98 +/- 1.04, P < .01), and Ethyl Arachidonate (MDI -2.40 +/- 1.11, P = .03; PDI -3.32 +/- 1.51, P = .03). CONCLUSION: FAEE in meconium may be a marker for identifying newborns at risk for neurodevelopmental delay from alcohol exposure in utero.

Prevalence of fetal ethanol exposure in a regional population-based sample by meconium analysis of fatty acid ethyl esters.[Pubmed:18367988]

Ther Drug Monit. 2008 Apr;30(2):239-45.

Challenges in identifying children exposed prenatally to ethanol necessitate the development of a biomarker for neonates at risk for fetal alcohol spectrum disorder. Meconium fatty acid ethyl esters (FAEE), products of nonoxidative ethanol metabolism, have been established as a novel biomarker of fetal ethanol exposure. We present the first application of this biomarker to a population-based sample in Canada. Six-hundred eighty-two meconium specimens were anonymously collected in the region of Grey Bruce, Ontario, Canada. Meconium FAEE were extracted by liquid-liquid and solid-phase extraction and analyzed by gas chromatography with flame-ionization detection confirmed by gas chromatography with mass spectrometry. We measured ethyl palmitate (E16:0), ethyl palmitoleate (E16:1), ethyl stearate (E18:0), ethyl oleate (E18:1), ethyl linoleate (E18:2), ethyl linolenate (E18:3), and Ethyl Arachidonate (E20:4). Seventeen of 682 meconium samples tested positive for significant prenatal ethanol exposure (>2.0 nmol/g). FAEE analysis detected fivefold more ethanol-exposed pregnancies than standard postpartum questionnaires in this population (2.5% versus 0.5%) (P < 0.001). The prevalence of ethanol-exposed pregnancies was consistent with Centers for Disease Control and Prevention estimates of "frequent" prenatal drinking and previously published estimates of fetal alcohol spectrum disorder disease prevalence in the general North American population. The FAEE concentrations of negative (95% confidence interval, 0.38-0.49 nmol/g) versus positive (95% confidence interval, 7.74-151.28 nmol/g) samples were distinct, further demonstrating the specificity of this biomarker in determining significant prenatal ethanol exposure. Meconium FAEE analysis demonstrates a fivefold increase in sensitivity over currently used methods of self-report-based screening in Ontario for the detection of ethanol-exposed pregnancies in a clinical setting.

Elevated fatty acid ethyl esters in meconium of sheep fetuses exposed in utero to ethanol--a new animal model.[Pubmed:18091344]

Pediatr Res. 2008 Feb;63(2):164-8.

Specific fatty acid ethyl esters (FAEE) in meconium of newborns have been shown to correlate with maternal ethanol exposure. An animal model is needed to assess the validity of this biomarker. We hypothesized that the pregnant/fetal sheep is a feasible animal model for validating FAEE as a biomarker of prenatal ethanol exposure. Nine pregnant ewes were treated during the third trimester with different i.v. ethanol doses. The control group consisted of 14 pregnant ewes exposed to similar volumes of saline. On gestational d 133, the fetuses were delivered and meconium samples removed. FAEEs were quantified by gas chromatography-flame ionization detection. FAEEs were found in both control and ethanol exposed fetuses. Ethyl oleate, ethyl linoleate, and Ethyl Arachidonate levels were significantly higher in the ethanol-exposed sheep. Ethyl oleate was the FAEE that correlated most strongly with alcohol ingestion during pregnancy and had the greatest area under the curve (0.94). Using a cut-off value of 131 ng/g ethyl oleate dry weight, sensitivity was 89% and specificity was 100%. In conclusion, pregnant ewes are a feasible model for validating biomarkers of prenatal ethanol exposure. Ethyl oleate, ethyl linoleate, and Ethyl Arachidonate may be useful biomarkers of prenatal alcohol exposure.