Fatal poisoning in drug addicts in the Nordic countries in 2007.

The frequency of medico-legally examined fatal poisonings in 2007 among drug addicts was investigated in five Nordic countries; Denmark, Finland, Iceland, Norway, and Sweden. The number of deaths, age, sex, place of death, main intoxicant, and other drugs present in blood samples were recorded to obtain national and comparable Nordic data, as well as data to compare with earlier studies in 2002, 1997, and 1991. Norway had the highest incidence of drug addict deaths by poisoning followed by Denmark, with 8.24 and 6.92 per 100,000 inhabitants, respectively. The death rates in Finland (4.02), Iceland (4.56), and Sweden (3.53) were about half that of Norway and Denmark. Compared with earlier studies, the death rates were unchanged in Denmark and Norway, but increased in Finland, Iceland, and Sweden. In all countries, fewer deaths (29-35%) were recorded in the capital area compared with earlier studies. Females accounted for 11-19% of the fatal poisonings. Iceland deviates with a more equal distribution between men and women (40%). Deaths from methadone overdoses increased in all Nordic countries, and methadone was the main intoxicant in Denmark in 2007, accounting for 51% of the poisonings. In Norway and Sweden, heroin/morphine was still the main intoxicant with a frequency of 68% and 48%, respectively. In Iceland, 3 deaths each were due to heroin/morphine and methadone, respectively. Finland differs from other Nordic countries in having a high number of poisonings caused by buprenorphine and very few caused by heroin/morphine. The total number of buprenorphine deaths in Finland doubled from 16 in 2002 to 32 in 2007, where it constituted 25% of deaths. The general toxicological screening program showed widespread multi-drug use in all countries. The median number of drugs per case varied from 3 to 5. The most frequently detected substances were heroin/morphine, methadone, buprenorphine, tramadol, amphetamine, cocaine, tetrahydrocannabinol, benzodiazepines and ethanol.

Determination of perfluorobutane in rat blood by automatic headspace capillary gas chromatography and selected ion monitoring mass spectrometry.

A new contrast agent (Sonazoid; NC100100) for ultrasound imaging has been developed. It is an aqueous suspension of lipid stabilised perfluorobutane (PFB) gas microbubbles. An automatic headspace capillary gas-chromatographic mass spectrometric method using electron impact ionisation was developed for analysis of Sonazoid PFB in rat blood. The calibration standards were gaseous PFB dissolved in ethanol in the range of 0.5-5000 ng PFB. Fluorotrichloromethane (CFC 11) was used as an internal standard of the method and the MS detector was set to single ion monitoring of the base fragment ions of PFB (m/z 69 and 119) and CFC 11 (m/z 101). The calibration graph, made by plotting the peak area ratios of PFB (m/z 69) to CFC 11(m/z 101) against the amount of PFB, was fitted to a second-order polynomial equation with weighting 1/y2 and found to be reproducible. The limit of quantification of the method was set to 0.4 ng PFB. The between-day variation of the method was below 9.2% relative standard deviation (RSD) and the within-day variation of the method was below 7.6% RSD. The accuracy of the method, as compared to Coulter counter, was estimated by determination of PFB in samples where Sonazoid was added to saline and found to range from 91.5% to 105.2%. PFB, added as Sonazoid, was found to be stable for at least 7 months in rat blood samples when stored at -20 degrees C.

In vivo stability and excretion of gadodiamide (GdDTPA-BMA), a hydrophilic gadolinium complex used as a contrast enhancing agent for magnetic resonance imaging.

The stability and excretion of [14C]-gadodiamide (GdDTPA-BMA) was studied in male rats after i.v. injection of 0.3 mmol/kg [14C]-GdDTPA-BMA (Gd-diethylenetriaminepentaacetic-acid-bis-methylamide) formulated as gadodiamide injection (OMNISCAN, Nycomed Imaging AS, Oslo, Norway). Samples of blood and urine obtained within 60 min and 6 h postdosing, respectively, were analyzed for radiolabeled compounds. Analysis of GdDTPA-BMA in high and low molecular weight fractions of serum indicated no protein binding. HPLC analyses of urine samples obtained 0-2 h, 2-4 h and 4-6 h after injection revealed no detectable amounts of biotransformation products of GdDTPA-BMA. Serum samples obtained 30 min and 60 min after injection contained 9-13 microM of an unidentified compound which had a retention time different from all conceivable metabolites of gadodiamide. A similar concentration of this unknown compound was found in spiked predose serum samples. The total amount of the unknown compound in serum was less than 1% of the injected dose of [14C]-gadodiamide injection. It is concluded that gadodiamide, when administered i.v. as gadodiamide injection at a dosage of 0.3 mmol/kg, is stable in vivo and that the very major part of the dose (> 99%) is excreted in urine as an unchanged complex.

Interference of gadodiamide injection (OMNISCAN) on the colorimetric determination of serum calcium.

The interference of the non-ionic magnetic resonance contrast medium gadodiamide injection (OMNISCAN, Nycomed Imaging, Oslo, Norway) in the colorimetric determination of serum calcium has been investigated in commercial reconstituted serum, and in serum from rabbits and humans dosed with the contrast medium. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and ion-selective electrodes were used as reference methods for analysis of serum calcium. The results showed that the colorimetric reagent kit gave an apparent decrease in serum calcium after administration of a clinical dose of gadodiamide injection, and that the extent of interference is correlated to the concentration of the contrast medium. However, serum calcium was not changed when measured by means of an ion-selective electrode or ICP-AES. It is therefore recommended that colorimetric reagent kits should not be used for determination of serum calcium in samples taken within the first 24 h after administration of gadodiamide injection.

Detection and quantitation of gadolinium chelates in human serum and urine by high-performance liquid chromatography and post-column derivatization of gadolinium with Arsenazo III.

A narrow-bore high-performance liquid chromatography method was developed for simultaneous separation of gadolinium diethylenetriaminepentaacetic acid (GdDTPA), the monomethylamide (GdDTPA-MMA) and the bis-methylamide (GdDTPA-BMA) in human serum and urine. The Gd complexes were detected at 658 nm after post-column derivatization with Arsenazo III. The serum samples were ultrafiltrated, whereas the urine samples were centrifuged and diluted before analysis. With an injection volume of 10 microliters on a 2.1 mm ID reversed-phase column, the limit of detection of GdDTPA-BMA was calculated as 0.3 microM and 1.1 microM in serum and urine, respectively. The method was validated with respect to GdDTPA-BMA with a limit of quantification set to 2 microM and 10 microM in serum and urine, respectively. The best fit of the calibration curve was obtained using non-linear regression according to the equation Y = A+BX+CX2 in the concentration ranges 2-800 microM and 10-2000 microM of GdDTPA-BMA in serum and urine, respectively. The precision of the method was found to range from 1 to 4% RSD. The recoveries of GdDTPA-BMA spiked in serum and urine were higher than 95% with an RSD equal to or less than 4%. The serum samples were stable for at least 5 months when stored at -70 degrees C, and the urine samples were stable for a least 6 months when stored at -20 degrees C.

Driving under the influence of toluene.

Toluene is the most common volatile used for sniffing among adolescents. During 1983-1987, 114 drivers were arrested in Norway with blood toluene concentrations (BTCs) greater than 10 microM. Only four of these drivers were women. The age range was 15-34 years, and the mean age was 21. The mean BTC was 109 microM. There was no simple relation between blood toluene concentration and degree of impairment, however, most drivers with BTCs greater than 100 microM were considered as impaired or probably impaired by toluene. In a five year prospective study of rearrests among drivers arrested for driving after toluene sniffing, 12 out of 15 drivers were rearrested. They were responsible for 40 cases of suspected driving under influence of toluene, alcohol, or other drugs. The blood levels of toluene determined in this study must be regarded as minimum concentrations, since the toluene concentration fell rapidly in samples stored at 4 degrees C or 23 degrees C. Blood samples from drivers suspected of driving under influence of toluene must therefore be kept frozen.

Fatal intoxications in the Nordic countries. A forensic toxicological study with special reference to young drug addicts.

Fatal intoxications in the 15-34 age group in the five Nordic countries during the years 1984 and 1985 (Sweden only in 1984) were investigated. The known drug addicts were studied separately. The highest incidence of intoxications, calculated per 10(5) population, was found in Finland (11.3), followed by Denmark (10.3), Sweden (8.5), Iceland (7.2) and Norway (6.6). The percentage of intoxications caused by drugs was 92 in Denmark, 71 in Norway, 66 in Sweden, 50 in Finland and 17 in Iceland. Ethanol intoxications were seen 5-7 and 2-3 times as frequently in Finland and in Iceland, respectively, than in the other three countries. Carbon monoxide intoxications accounted for two-thirds of all fatal intoxications in Iceland. Drug addicts accounted for 62% of all fatal intoxications in the Danish material. The corresponding figures were 33% in the Norwegian, 16% in the Swedish and 5% in the Finnish material. No deaths in drug addicts were found in Iceland. Most drug addicts in Denmark, Norway and Sweden died of hard drugs and most in Norway and Sweden, from heroin or morphine, whereas in Denmark other strong analgesics, such as methadone, dextropropoxyphene and ketobemidone, accounted for 40% of all hard-drug-related fatal intoxications. To a certain extent the results reflect differences in the legal autopsy routines in the various Nordic countries. However, the ascertainment of drug addicts is assumed to be near-complete in each country.

An experimental study on ethanol elimination at subphysiological temperatures.

Hepatocytes isolated from fed and fasted rats have been used to study the rate of ethanol elimination at different incubation temperatures. In the presence of exogenous pyruvate, hepatocytes from fed and 42 hr fasted rats, eliminated ethanol at 37 degrees by a rate of 11.6 +/- 3.4 and 6.4 +/- 0.8 nmol/min./mg of cell protein (+/- S.D.; n = 5), respectively, which are comparable to the rates obtained in vivo. The ethanol oxidation rate in cells from rats of both nutritional states correlated linearily to the incubation temperature (t = 24-37 degrees) with a temperature coefficient (Q10) of 1.8-2.3. (Q10, (= temperature coefficient) is the factor by which the enzyme activity is increased on raising the temperature 10 degrees). These findings indicate that the oxidation is not controlled by processes which involve membrane transitions in the temperature range 24-37 degrees. Our results indicate that a hypothermic individual with a body temperature of 27 degrees would have a 40-50 per cent inhibition of the ethanol elimination rate. Thus, the observed dependency of the ethanol oxidation on the body temperature has to be regarded in back-calculations of blood ethanol concentrations in forensic toxicology.

Diethyl ether inhibits ethanol metabolism in vivo by interaction with alcohol dehydrogenase.

The ethanol disappearance rate was determined in fed rats given 20-40 mM ethanol and anesthetized with pentobarbital (control group) and diethyl ether. The control ethanol disappearance rate was 0.27 +/- 0.02 mM/min (+/- SD, n = 4). Rats anesthetized with diethyl ether (blood levels of 9-13 mM) revealed an ethanol disappearance rate of 0.13 +/- 0.05 mM/min (+/- SD, n = 7), i.e., 52% inhibition of the control rate. Kinetic studies on crystalline and lyophilized alcohol dehydrogenase from equine liver demonstrated that 20 mM diethyl ether inhibited the initial rate of ethanol oxidation by 55%. By using ethanol as the variable substrate the inhibition of alcohol dehydrogenase was described by a mixed noncompetitive/uncompetitive mechanism.

Determination of serum tryptophan by isocratic high-performance liquid chromatography and ultraviolet detection.

A simple method for the determination of serum tryptophan is described. Serum proteins were precipitated using ethanol, and after a centrifugation, tryptophan concentrations were measured in the supernatant using isocratic high performance liquid chromatography with ultraviolet detection at 219 nm. All serum compounds absorbing at this wavelength were eluted within 6 min; the retention time for tryptophan was 3.95 min. This method is simpler and more rapid than previously published methods, and the results are reliable. The coefficient of variation of the analysis was found to be less than 6.5%.

Acute interaction of halothane and enflurane with the metabolism of ethanol in isolated hepatocytes and liver cytosol preparations from the rat.

The effects of halothane and enflurane on ethanol (40 mM) oxidation were studied in isolated rat hepatocytes. Anaesthetic (halothane, enflurane and diethyl ether) effect on the activity of alcohol dehydrogenase (ADH) was studied in incubations of cytosol preparations from rat liver. Mean rates of ethanol metabolism ranged from 0.44 to 0.49 mumol ethanol metabolized/mg cell protein/hour in control hepatocytes from fasted and fed animals. These rates were enhanced by 2- and 3-fold in hepatocytes from fed and fasted animals, respectively, when pyruvate (5 mM) was added. Halothane and enflurane both caused dose dependent inhibition of ethanol metabolism (15-40%) in all hepatocytes without exogenous addition of pyruvate. The inhibitory effect was present also after pyruvate stimulation in hepatocytes from fasted animals, but disappeared in hepatocytes from fed animals when pyruvate was added. The rate of ethanol oxidation by cells from fed rats was enhanced by approximately 40% when the concentration of ethanol was increased from 20 mM to 80 mM. The anaesthetic inhibition of ethanol metabolism was about 20% more pronounced at the higher ethanol concentration compared to the lower concentration when no pyruvate was added. In the presence of pyruvate the effect of anaesthetics was again reversed regardless of ethanol concentration. Halothane (2 mM) and enflurane (2 mM) both caused about 25% inhibition of the ADH-activity in cytosol preparations while ether (30 mM) caused more than 50% inhibition. No inhibition of hepatocyte uptake of ethanol was caused by any of the three anaesthetics.(ABSTRACT TRUNCATED AT 250 WORDS)

Increase in mitochondrial content of long-chain acyl-CoA in brown adipose tissue during cold-acclimation.

The mitochondrial content of long-chain acyl-CoA esters in the brown adipose tissue of guinea pigs increased 3.5-fold from a level of 92 +/- 17 pmol per mg protein (+/- S.E.; n = 7) in the control animals adapted at 22 degrees C to a new steady-state level of 328 +/- 20 pmol per mg protein (+/- S.E.; n = 46) after 10 days of cold-acclimation (5 degrees C). These low values of long-chain acyl-CoA species and the slow adaptive response for their increase do not support the proposal (Cannon, B., Sindin, U. and Romert, L. (1977) FEBS Lett. 4, 43-46) that the fatty acid CoA-esters have a physiological function in the regulation of the H+ (or OH-) permeability of the mitochondrial inner membrane. Experimental evidence is presented supporting the proposal that the long-chain acyl-CoA species are largely confined to the cytosolic side of the inner membrane. The activity of the adenine nucleotide translocase, as estimated at 25 degrees C in the reverse direction, was found to increase 5-fold upon depletion of the mitochondria of fatty acids (free and esterified) by preincubation with bovine serum albumin. The presence of potent inhibitors, i.e., long-chain acyl-CoA species, of adenine nucleotide translocation in brown adipose tissue of thermogenically active animals further supports the conclusion that ATP hydrolyzing mechanisms contribute insignificantly to long-term thermogenesis. The low values of long-chain acyl-CoA hydrolase (EC 3.1.2.1) activity, as measured in intact mitochondria and on a mitochondrial matrix fraction (i.e., 1.6 nmol X min-1 per mg protein), do not support the proposal that the hydrolase activity plays a significant role in the loose-coupling of brown adipose tissue mitochondria, either by a futile cycle mechanism or promoted by free fatty acid-induced uncoupling.

Acyl-CoA synthetase activity of rat heart mitochondria. Substrate specificity with special reference to very-long-chain and isomeric fatty acids.

The acyl-CoA synthetase (acid: CoA ligase (AMP-forming), EC 6.2.1.3) activity of rat heart has been measured in fatty acid-depleted fractions of mitochondria, microperoxisomes and microsomes. The assay was based on (i) the measurement of the reaction product AMP by high-performance liquid chromatography or (ii) a coupled reaction in which the intramitochondrial (matrix) CoASH is the final acyl acceptor and the redox state of the flavoproteins in the acyl-CoA dehydrogenase pathway is used to determine the intramitochondrial level of acyl-CoA. This spectrophotometric method was also used to estimate the 'outer' carnitine long-chain acyltransferase (palmitoyl-CoA:L-carnitine O-palmitoyltransferase, EC 2.3.1.21) activity. Comparison of the distribution of long-chain acyl-CoA synthetase activity and marker enzymes in the various subcellular fractions revealed that the synthetase activity is exclusively localized in the mitochondrial fraction. Experimental evidence is presented in support of the conclusion that the chain-length specificity of saturated and monounsaturated fatty acids (16:1-22:1) for the acyl-CoA synthetase is mainly determined by the availability of the fatty acid at the active site, which is largely determined by the affinity of binding of fatty acids to the bulk phase of the mitochondrial phospholipids. Among the 22:1 isomers, 22:1(11) (cis) (cetoleic acid) revealed a slightly higher activity (1.4-fold) than 22:1(13) (cis) (erucic acid). The polyunsaturated fatty acids tested were rather poor substrates. Using isolated intact mitochondria and 16:0 or 22:1(13) (cis) as the substrates, it was found that the initial rate of the 'outer' long-chain acyltransferase activity was approximately four times higher than that of the long-chain acyl-CoA synthetase. The data support the hypothesis that the long-chain acyl-CoA synthetase reaction is rate-limiting in the sequence of coupled reactions leading to beta-oxidation in the mitochondrial matrix.

Hydrodynamic parameters and isolation of mitochondria, microperoxisomes and microsomes of rat heart.

1. Analytical differential centrifugation of rat heart homogenates revealed a single population of mitochondria and microperoxisomes. Using cytochrome c oxidase, malate dehydrogenase and amine oxidase as mitochondrial marker enzymes, the s-value of mitochondria was estimated to s = 10326 +/- 406 S (average for the three marker enzymes). The s-value of microperoxisomes was found to be s = 1381 +/- 40 S using catalase as the marker enzyme. The s-value for the two organelles did not change significantly when the isoosmotic sucrose medium was substituted by an isoosmotic mannitol medium. 2. Analytical differential centrifugation revealed a polydispercity of the microsomal fraction using glucose-6-phosphatase and NADPH-cytochrome c reductase as the marker enzymes. The s-values were found to be sH1 = 1569 +/- 412 S (NADPH-cytochrome c reductase), sH2 = 1195 +/- 400 S (glucose-6-phosphatase) and sL = 153 +/- 28 S (NADPH-cytochrome c reductase and glucose-6-phosphatase). The recovery of marker enzymes in the isolated subcellular fractions was in the range of 84-94%. 3. When the mitochondrial and microperoxisomal fractions were subjected to isopycnic gradient centrifugation, using a self-generating gradient of polyvinylpyrrolidone-coated colloidal silica particles (Percoll) in 0.25 M sucrose medium, buoyant densities of 1.10 g/cm3 (main fraction of mitochondria) and 1.06 g/cm3 (main fraction of microperoxisomes) were obtained. The density gradient centrifugation separated microperoxisomes from contaminating lysosomes of high specific activity in acid phosphatase. A value 1.04 g/cm3 was found for the density of the microsomal fraction. 4. Based on the estimated s-values, an optimal procedure is described for the isolation of mitochondrial and microperoxisomal fractions from rat heart muscle.

Microperoxisomes and mitochondria of brown adipose tissue. Hydrodynamic parameters, isolation and capacity of long-chain fatty acid oxidation.

1. Analytical differential centrifugation of brown adipose tissue homogenates from cold-acclimated guinea pigs revealed a polydispersity of both mitochondria and peroxisomes, with at least two populations of each organelle. The estimated values were sH = 16685+/-4220 S and sL = 4792+/-951 S (mitochondria), and sH = 3364+/-1706 S and sL = 889+/-177 S (peroxisomes). Based on these s values, an optimal procedure is described for the isolation of subcellular fractions enriched in mitochondria and peroxisomes, respectively. 2. When the mitochondrial and peroxisomal fractions were subjected to isopycnic gradient centrifugation on a self-generating gradient of poly(vinylpyrrolidone)-coated colloidal silica particles (Percoll) in 0.25 M sucrose medium, buoyant densities of about 1.11 g/cm3 (main fraction of mitochondria) and 1.07 g/cm3 (main fraction of peroxisomes) were obtained. A value of 1.06 g/cm3 was found for the microsomal fraction. 3. The main peroxisomal fraction, isolated by gradient centrifugation, did not reveal any significant oxidation of palmitoyl-CoA as measured by conventional polarographic technique, whereas a small rate of oxidation (about 2.7+/-0.2 nmol/min per mg peroxisomal protein) was observed when measured as NAD+ reduction. This rate contributes no more than 1% of the mitochondrial oxidation of this fatty acid and it is, therefore, concluded that peroxisomal oxidation of the predominant long-chain fatty acids found in this tissue does not make a quantitatively significant contribution to fatty acid oxidation.

Transport of ascorbate into guinea pig liver mitochondria.

The amount of ascorbate associated with guinea pig liver mitochondria was estimated by high-performance liquid chromatography. Incubation of mitochondria with ascorbate revealed a time-dependent and temperature-dependent accumulation of the vitamin. A steady-state level of ascorbate was obtained in the mitochondria after about 20 min of incubation at 37 degrees C, whereas no accumulation was observed at 0 degrees C. The matrix concentration of ascorbate was highly correlated to the concentration of ascorbate in the incubation medium. The initial rate of accumulation (about 7 pmol/mg protein per min at 10 degrees C) was three orders of magnitude less than for compounds that are transported across the mitochondrial inner membrane by specific carriers. Experiments with the enzyme ascorbate oxidase demonstrated that the mitochondrial membrane is also permeable to dehydroascorbate, and that the accumulated dehydroascorbate is stable in the mitochondria. There was no effect of the energy state of the mitochondrial membrane of the initial transport rate of ascorbate. Electrostatic binding of ascorbate to the membrane was excluded from experiments performed in isosmotic potassium chloride medium. Diffusion of ascorbate across the mitochondrial inner membrane accounts for the experimental findings.

Acyl-CoA synthetase activity of rat liver microsomes. Substrate specificity with special reference to very-long-chain and isomeric fatty acids.

1. A fatty acid-depleted rat liver microsomal fraction has been used for the measurement of acyl-CoA synthetase (acid : CoA ligase (AMP-forming), EC 6.2.1.3) activity. The assay was based on measurement of the reaction product AMP by high-performance liquid chromatography (HPLC). The synthetase activity (V') revealed an optimum at 12 : 0 with saturated fatty acids as substrate, and at 14 : 1 with mono-unsaturated fatty acids. The apparent Michaelis constant, on the other hand, showed no systematic dependence on the fatty acid chain-length. 2. The mono-unsaturated fatty acids from 14 : 1 to 22 : 1 gave higher activities than the corresponding saturated fatty acids, and the relative differences were greatest with the very-long-chain fatty acids eicosaenoic (20 : 1 (11) (cis)) and docosaenoic acid (22 : 1 (11) (cis)). The synthetase activity with saturated and mono-unsaturated fatty acids was found to correlate to their capacity factor (k') on reversed phase chromatography (HPLC). This finding may indicate that the observed chain-length dependence of the activity largely reflects the partition of the fatty acids between a hydrophobic and a hydrophilic phase. In general, the position of the double bond and the cis/trans configuration had little effect on the V' values except for 22 : 1 (11)(cis) which revealed a 2-fold higher activity tha 22 : 1 (13) (cis). 3. The polyunsaturated fatty acid 22 : 6 (all cis) ;was notably found to be a much better substrate than other C22 fatty acids. 4. The present study does not support the idea of more than a single ATP-dependent acyl-CoA synthetase in the rat liver microsomal fraction.

Acyl-CoA synthetase activity of brown adipose tissue mitochondria. Substrate specificity and its relation to the endogenous pool of long-chain fatty acids.

1. A new assay of acyl-CoA synthetase (acid:CoA ligase (AMP-forming), EC 6.2.1.3) activity was developed for application to measurements on isolated intact mitochondria. The assay was based on the formation of the product AMP as determined by high-performance liquid chromatography (HPLC), making corrections for the partial conversion of AMP to ADP by the adenylate kinase reaction. 2. The substrate specificity of the long-chain acyl-CoA synthetase was measured in brown adipose tissue mitochondria, isolated from cold-acclimated guinea-pigs. Using mitochondria largely deficient of endogenous fatty acids, the synthetase activity (V') revealed an optimum at 12 :0 and 13 : 0 with saturated fatty acids as the substrate. In contrast to other tissues, the highest V' values were observed with unsaturated fatty acids 18 : 1 (9) (cis) and 18 : 2 (9, 12) (all cis). The apparent Michaelis constant varied within a narrow range and revealed no systematic dependence on the chain-length as was the case for V'. Since the mitochondria have a high capacity of fatty acid binding, with unknown affinity, the estimated K'm values are, however, of questionable significance. 3. The pattern of chain-length specificity in the synthetase reaction of the mitochondria compares well with the pattern of endogenous long-chain fatty acids in which mainly four species contribute, i.e. 18 : 1 (42 mol%) and 18 : 2 (18 mol%), 16 : 0 (26 mol%) and 18 : 0 (14 mol%).