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PubMed1988

Dietary linolenic acid and longer-chain n-3 fatty acids: comparison of effects on arachidonic acid metabolism in rats.

Rats were fed graded amounts of purified 18:3n-3 or fish oil concentrate in the presence of a constant amount of 18:2n-6 to evaluate the ability of 18:3n-3 compared with longer-chain n-3 fatty acids to inhibit 20:4n-6 metabolism in platelets and lungs. Dietary 18:3n-3 at a ratio of 0.28 (n-3 to n-6 fatty acids) suppressed levels of 20:4n-6 in lung and plasma phospholipids and the capacity of the tissues to synthesize cyclooxygenase-derived products in a dose-dependent fashion. At similar ratios of n-3 to n-6 dietary fatty acids, longer-chain n-3 fatty acids, which are abundant in fish oil, appear to be more effective than 18:3n-3 in suppressing 20:4n-6 levels and the capacity of the tissues to synthesize cyclooxygenase-derived products. Much greater amounts of 12-hydroxyeicosapentaenoic acid (12-HEPE) and 5-HEPE than of 12-hydroxyeicosatetraenoic acid (12-HETE) and 5-HETE appeared to be formed in tissues of the group receiving the highest amount of fish oil. These results suggest that ingestion of fish oil leads to increased formation of lipoxygenase-derived products of longer-chain n-3 fatty acids.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMed1999

Effects of gamma-linolenic acid and docosahexaenoic acid in formulae on brain fatty acid composition in artificially reared rats.

This study evaluated the effects of dietary supplementation with gamma-linolenic acid (GLA, 18:3n-6) and docosahexaenoic acid (DHA, 22:6n-3) on the fatty acid composition of the neonatal brain in gastrostomized rat pups reared artificially from days 5-18. These pups were fed rat milk substitutes containing fats that provided 10% linoleic acid and 1% alpha-linolenic acid (% fatty acids) and, using a 2x3 factorial design, one of two levels of DHA (0.5 and 2.5%), and one of three levels of GLA (0.5, 1.0, and 3.0%). A seventh artificially reared group served as a reference group and was fed 0.5% DHA and 0.5% arachidonic acid (AA, 20:4n-6); these levels are within the range of those found in rat milk. The eighth group, the suckled control group, was reared by nursing dams fed a standard American Institute of Nutrition 93M chow. The fatty acid composition of the phosphatidylethanolamine, phosphatidylcholine, and phosphatidylserine/phosphatidylinositol membrane fractions of the forebrain on day 18 reflected the dietary composition in that high levels of dietary DHA resulted in increases in DHA but decreases in 22:4n-6 and 22:5n-6 in brain. High levels of GLA increased 22:4n-6 but, in contrast to previous findings with high levels of AA, did not decrease levels of DHA. These results suggest that dietary GLA, during development, differs from high dietary levels of AA in that it does not lead to reductions in brain DHA.

Animals↗

PubMed1984

Fatty acid metabolism in Paramecium. Oleic acid metabolism and inhibition of polyunsaturated fatty acid synthesis by triparanol.

Paramecium requires oleic acid for growth and can grow in media containing no other fatty acids. In the present study, we have shown that this ciliate utilized oleate mainly as a carbon and energy source, even though this fatty acid was the only substrate available for synthesis of polyunsaturated fatty acids. Culture growth was inhibited by the addition of the drug triparanol. Triparanol decreased the formation of polyunsaturated fatty acids from oleate by preventing desaturation to form the dienoic acid, linoleate. Triparanol inhibition resulted in an altered phospholipid fatty acyl composition, an increased fragility and an altered behavioral response of the cells to a depolarizing stimulation solution. Therefore, although most of the dietary oleate was not used by the cells for polyunsaturated fatty acid synthesis, the desaturation of oleic acid was critical for normal culture growth, cell integrity and swimming behavior, all of which are expected to be dependent on normal membrane lipid composition.

Animals↗

PubMed1984

Comparative effects of indomethacin, acetylenic acids, 15-HETE, nordihydroguaiaretic acid and BW755C on the metabolism of arachidonic acid in human leukocytes and platelets.

Human leukocytes and platelets were preincubated with inhibitors of the oxidative metabolism of arachidonic acid, viz, indomethacin, BW755C, 5, 8, 11, 14-eicosatetraynoic acid (ETYA), 5, 8, 11-eicosatriynoic acid, 15S-hydroxy-5, 8, 11, 13-(Z, Z, Z, E)-eicosatetraenoic acid (15-HETE) and nordihydroguaiaretic acid (NDGA), prior to stimulation with the ionophore A23187 in the presence or absence of exogenous arachidonic acid. Eleven metabolites of arachidonic acid derived from the cyclooxygenase and the 5-, 12- and 15-lipoxygenases were measured by reversed-phase high pressure liquid chromatography (RP-HPLC). Indomethacin was the best inhibitor of the platelet cyclooxygenase (ID50 less than 10(-7)M) as assessed by measurement of 12-hydroxy-heptadecatrienoic acid (HHT); ETYA was the most potent inhibitor of the 12- and 15-lipoxygenases (ID50 approximately 3 X 10(-7)M) whereas NDGA was the most potent and selective inhibitor of the 5-lipoxygenase (ID50 approximately 3 X 10(-7)M).

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗

PubMed1998

Fatty acid alpha-oxidation of tetradecylthioacetic acid and tetradecylthiopropionic acid in cucumber (Cucumis sativus).

Fatty acid alpha-oxidation in cucumber (Cucumis sativus) involves enzymatic conversion of long-chain Cn-fatty acids to the C(n-1)-aldehyde and CO2. However, the mechanism of this process is not well understood. In this study, the alpha-oxidation of the fatty acid analogues tetradecylthioacetic acid (TTA) and tetradecylthiopropionic acid (TTP) with a sulphur atom substituting the methylene group in positions 3 and 4, respectively, was investigated and compared to palmitic acid. Both [1-14C]TTA and [1-14C]TTP could be alpha-oxidised in the cucumber subcellular 150000xgmax fraction. [1-14C]TTP was an even better substrate compared to the natural palmitic acid, while [1-14C]TTA was alpha-oxidised to a lower extent. [2-14C]TTA revealed no 14CO2, indicating that only one cycle of alpha-oxidation occurred. TTA was an inhibitor of the palmitic acid alpha-oxidation, and the inhibitory effects were examined.

Animals↗

PubMed2003

Ion-exclusion chromatography with conductimetric detection of aliphatic carboxylic acids on a weakly acidic cation-exchange resin by elution with benzoic acid-beta-cyclodextrin.

In this study, an aqueous solution consisting of benzoic acid with low background conductivity and beta-cyclodextrin (beta-CD) of hydrophilic nature and the inclusion effect to benzoic acid were used as eluent for the ion-exclusion chromatographic separation of aliphatic carboxylic acids with different pKa values and hydrophobicity on a polymethacrylate-based weakly acidic cation-exchange resin in the H+ form. With increasing concentration of beta-cyclodextrin in the eluent, the retention times of the carboxylic acids decreased due to the increased hydrophilicity of the polymethacrylate-based cation-exchange resin surface from the adsorption of OH groups of beta-cyclodextrin. Moreover, the eluent background conductivity decreased with increasing concentration of beta-cyclodextrin in 1 mM benzoic acid, which could result in higher sensitivity for conductimetric detection. The ion-exclusion chromatographic separation of carboxylic acids with high resolution and sensitivity was accomplished successfully by elution with a 1 mM benzoic acid-10 mM cyclodextrin solution without chemical suppression.

Adsorption↗

PubMedDate not supplied

Carboxymethyl-substituted bifunctional chelators: preparation of aryl isothiocyanate derivatives of 3-(carboxymethyl)-3-azapentanedioic acid, 3,12-bis(carboxymethyl)-6,9-dioxa-3,12-diazatetradecanedioic++ + acid, and 1,4,7,10-tetraazacyclododecane-N,N',N",N'''-tetraacetic acid for use as protein labels.

3-(Carboxymethyl)-3-azapentanedioic acid (NTA), 3,12-bis(carboxymethyl)-6,9-dioxa-3,12-diazatetradecanedioic acid (EGTA), and 1,4,7,10-tetraazacyclododecane-N,N',N",N'''-tetraacetic acid (DOTA) structures having a 4-nitrophenyl substituent attached via an alkyl spacer to the methylene carbon atom of one carboxymethyl arm of the chelator were obtained by alkylation of 4-nitrophenylalanine with bromoacetic acid (NTA), by reductive alkylation of 1,8-diamino-3,6-dioxaoctane with (4-nitrophenyl)-pyruvic acid followed by alkylation with bromoacetic acid (EGTA), and by alkylation of the trimethyl ester of 1,4,7,10-tetraazacyclododecane-N,N',N"-triacetic acid with the methyl ester of alpha-bromo-4-(4-nitrophenyl)pentanoic acid and subsequent saponification (DOTA). The nitrophenyl-substituted chelators were converted to the corresponding amines by hydrogenation then reacted with thiophosgene to give the protein-reactive aryl isothiocyanate derivatives.

Aza Compounds↗

PubMed2004

Electrophilic amination of amino acids with N-Boc-oxaziridines: efficient preparation of N-orthogonally diprotected hydrazino acids and piperazic acid derivatives.

A general two-step preparation of enantiopure N(alpha),N(beta)-orthogonally diprotected alpha-hydrazino acids 1 is developed on a multigram scale. The key reaction is the efficient electrophilic amination of N-benzyl amino acids 6 with N-Boc-oxaziridine 7 and accommodates various functional groups encountered in side chains of amino acids. The cyclic 2,3,4,5-tetrahydro-3-pyridazine carboxylic acid (piperazic acid) derivatives 2 and 3 or the cyclic 3,4-dihydro-3-pyrazolecarboxylate 4 are conveniently prepared from glutamic acid or aspartic acid via orthogonally diprotected alpha-hydrazino acids 1m and 1n.

Amination↗

PubMed1995

alpha-Linolenic acid- and docosahexaenoic acid-enriched eggs from hens fed flaxseed: influence on blood lipids and platelet phospholipid fatty acids in humans.

This study was undertaken to examine the effects that consumption of eggs from hens fed diets containing flaxseed would have on plasma and platelet lipids of male volunteers. Feeding diets containing 0%, 10%, and 20% ground flaxseed to Leghorn pullets provided a marked progressive increase in n-3 fatty acid content as alpha-linolenic acid (alpha-LNA) (28, 261, and 527 mg/egg) and docosahexaenoic acid (DHA) (51, 81, and 87 mg/egg) but no alteration in the cholesterol concentration of the egg yolk. Twenty-eight male volunteers, divided into three groups, were fed four eggs per day for 2 wk according to a cyclic Latin-square design. No statistically significant changes were observed in total cholesterol, high-density-lipoprotein cholesterol, or plasma triglyceride concentrations. Significant increases in total n-3 fatty acids and in DHA content (which rose from 1.5 to 2.0% by wt or 33% overall), and a significant decrease in ratio of n-6 to n-3 fatty acids were found in platelet phospholipids of subjects consuming eggs from flaxseed-fed hens. Health and Welfare Canada in 1990 set recommended intakes for dietary n-3 fatty acids and for the ratio of n-6 to n-3 fatty acids, which are not being met currently by the overall population. Eggs modified by the inclusion of flaxseed in the laying hens' diet could provide an important nutritional source of n-3 fatty acid.

Adult↗

PubMed1998

Long-chain polyunsaturated fatty acid levels in formulae influence deposition of docosahexaenoic acid and arachidonic acid in brain and red blood cells of artificially reared neonatal rats.

We studied the effects of dietary long-chain polyunsaturated fatty acids (PUFA) on the fatty acid composition of the brain and red blood cells in gastrostomized rat pups reared artificially from postnatal Days 5-18. These pups were fed rat milk substitutes in which the fat comprised 10% linoleic acid and 1% alpha-linolenic acid and, using a 3 x 3 factorial design, one of three levels of both arachidonic acid (AA) and docosahexaenoic acid (DHA) supplied as single cell microbial oils (0.0, 0.4 and 2.4% fatty acids). A tenth group was reared by nursing dams. The fatty acid composition of the phosphatidylethanolamine (PE) and phosphatidylserine/phosphatidylinositol (PS/PI) phospholipids in the brain and red blood cells on Day 18 reflected the dietary composition in that pups receiving long-chain supplementation of each had higher levels of the supplemented PUFA, but lower levels of the other, relative to unsupplemented groups. In contrast to these results, there were few changes in the brain in phosphatidylcholine (PC) phospholipids whereas, in the red blood cells, changes in PC were similar to those in PE and PS/PI. Regression analyses showed that DHA levels in the brain correlated more closely with those of the red blood cells than did AA levels. The results of this study indicate that, although supplementation of formula with AA or DHA during the period of rapid brain development in rats increases deposition of the long-chain PUFA in the developing tissues, each also affects the levels of the other.

Animals↗

PubMed1991

Unique fatty acid composition of normal cartilage: discovery of high levels of n-9 eicosatrienoic acid and low levels of n-6 polyunsaturated fatty acids.

We report here the finding that normal, young cartilages, in distinction from all other tissues examined, have unusually high levels of n-9 eicosatrienoic (20:3 cis-delta 5,8,11) acid and low levels of n-6 polyunsaturated fatty acids (n-6 PUFA). This pattern is identical to that found in tissues of animals subjected to prolonged depletion of nutritionally essential n-6 polyunsaturated fatty acids (EFA). This apparent deficiency is consistently observed in cartilage of all species so far studied (young chicken, fetal calf, newborn pig, rabbit, and human), even though levels of n-6 PUFA in blood and all other tissues is normal. The n-9 20:3 acid is particularly abundant in phosphatidylethanolamine, phosphatidylinositol, and the free fatty acid fractions from the young cartilage. Several factors appear to contribute to the reduction in n-6 PUFA and the appearance of high levels of the n-9 20:3 acid in cartilage: 1) limited access to nutritional sources of EFA due to the impermeability and avascularity of cartilage, 2) rapid metabolism of n-6 PUFA to prostanoids by chondrocytes, and 3) a unique fatty acid metabolism by cartilage. Evidence is presented that each of these factors contributes. Previously, EFA deficiency has been shown to greatly suppress the inflammatory response of leukocytes and rejection of tissues transplanted into allogeneic recipients. Because eicosanoids, which are derived from EFA, have been implicated in the inflammatory responses associated with arthritic disease, reduction of n-6 PUFA and accumulation of the n-9 20:3 acid in cartilage may be important for maintaining normal cartilage structure.

8,11,14-Eicosatrienoic Acid↗

PubMed2004

Inactivation of the lys7 gene, encoding saccharopine reductase in Penicillium chrysogenum, leads to accumulation of the secondary metabolite precursors piperideine-6-carboxylic acid and pipecolic acid from alpha-aminoadipic acid.

Pipecolic acid serves as a precursor of the biosynthesis of the alkaloids slaframine and swainsonine (an antitumor agent) in some fungi. It is not known whether other fungi are able to synthesize pipecolic acid. Penicillium chrysogenum has a very active alpha-aminoadipic acid pathway that is used for the synthesis of this precursor of penicillin. The lys7 gene, encoding saccharopine reductase in P. chrysogenum, was target inactivated by the double-recombination method. Analysis of a disrupted strain (named P. chrysogenum SR1-) showed the presence of a mutant lys7 gene lacking about 1,000 bp in the 3'-end region. P. chrysogenum SR1- lacked saccharopine reductase activity, which was recovered after transformation of this mutant with the intact lys7 gene in an autonomously replicating plasmid. P. chrysogenum SR1- was a lysine auxotroph and accumulated piperideine-6-carboxylic acid. When mutant P. chrysogenum SR1- was grown with L-lysine as the sole nitrogen source and supplemented with DL-alpha-aminoadipic acid, a high level of pipecolic acid accumulated intracellularly. A comparison of strain SR1- with a lys2-defective mutant provided evidence showing that P. chrysogenum synthesizes pipecolic acid from alpha-aminoadipic acid and not from L-lysine catabolism.

2-Aminoadipic Acid↗

PubMed2003

Intestinal absorption of the bile acid analogue 75Se-homocholic acid-taurine is increased in primary biliary cirrhosis, and reverts to normal during ursodeoxycholic acid administration.

BACKGROUND: Whether ileal absorption of bile acid is up or downregulated in chronic cholestasis is still debated, and most evidence has come from animal studies. AIMS: To compare ileal bile acid absorption in patients with primary biliary cirrhosis (PBC) and in healthy control subjects, and to assess the effect of ursodeoxycholic acid (UDCA). PATIENTS: We studied 14 PBC patients before and during (n=11) UDCA administration, 14 healthy control subjects, and 14 Crohn's disease patients (as disease controls). METHODS: We used cholescintigraphy to measure retention in the enterohepatic circulation over five successive days of the bile acid analogue (75)Se-homocholic acid-taurine ((75)SeHCAT) as an index of ileal bile acid absorption. Results were expressed as (75)SeHCAT fractional turnover rate (FTR) and t(1/2)12. RESULTS: (75)SeHCAT FTR was 0.19 (0.11)/day, 0.34 (0.11)/day (p<0.001), and 0.83 (0.32)/day in PBC patients, healthy controls (p<0.0001), and Crohn's patients (p<0.001), respectively, which increased to 0.36 (0.16)/day in PBC patients during UDCA treatment (p<0.005). (75)SeHCAT t(1/2)12 was 4.8 (2.1) days in PBC patients, 2.2 (0.5) days (p<0.001) in healthy controls, and 1.0 (0.5) days (p<0.001) in Crohn's disease patients. (75)SeHCAT t(1/2)12 decreased to 2.2 (0.93) days (p< 0.001) in PBC patients during UDCA treatment. CONCLUSIONS: Our results support the concept that ileal bile acid absorption is upregulated in PBC patients, and that this effect may contribute towards damaging the cholestatic liver. This upregulation of bile acid absorption is abolished by UDCA.

Adult↗

PubMed2000

Fish oil-derived fatty acids, docosahexaenoic acid and docosapentaenoic acid, and the risk of acute coronary events: the Kuopio ischaemic heart disease risk factor study.

BACKGROUND: Previous findings concerning the serum levels of fish-derived (n-3) fatty acids and coronary heart disease are inconsistent. The purpose of this study was to investigate the association between the serum n-3 end-product fatty acids docosahexaenoic acid (DHA), docosapentaenoic acid (DPA), and eicosapentaenoic acid and the risk of acute coronary events in middle-aged men. METHODS AND RESULTS: We studied this association in the Kuopio Ischaemic Heart Disease Risk Factor Study, a prospective population study in Eastern Finland. Subjects were randomly selected and included 1871 men aged 42 to 60 years who had no clinical coronary heart disease at baseline examination. A total of 194 men had a fatal or nonfatal acute coronary event during follow-up. In a Cox proportional hazards' model adjusting for other risk factors, men in the highest fifth of the proportion of serum DHA+DPA in all fatty acids had a 44% reduced risk (P=0.014) of acute coronary events compared with men in the lowest fifth. Men in the highest fifth of DHA+DPA who had a low hair content of mercury (</=2.0 microgram/g) had a 67% reduced risk (P=0.016) of acute coronary events compared with men in the lowest fifth who had a high hair content of mercury (>2.0 microgram/g). There was no association between proportion of eicosapentaenoic acid and the risk of acute coronary events. CONCLUSIONS: Our data provide further confirmation for the concept that fish oil-derived fatty acids reduce the risk of acute coronary events. However, a high mercury content in fish could attenuate this protective effect.

Acute Disease↗

PubMed1991

Purification and amino acid sequence of a bitter gourd inhibitor against an acidic amino acid-specific endopeptidase of Streptomyces griseus.

An inhibitor (BGIA) against an acidic amino acid-specific endopeptidase of Streptomyces griseus (Glu S. griseus protease) was isolated from seeds of the bitter gourd Momordica charantia L., and its amino acid sequence was determined. The molecular weight of BGIA based on the amino acid sequence was calculated to be 7419. BGIA competitively inhibited Glu S. griseus protease with an inhibition constant (Ki) of 70 nM, and gel filtration analyses suggested that BGIA forms a 1:1 complex with this protease. However, two other acidic amino acid-specific endopeptidases, protease V8 from Staphylococcus aureus and Bacillus subtilis proteinase (Glu B. subtilis protease), were not inhibited by BGIA. BGIA had no inhibitory activity against chymotrypsin, trypsin, porcine pancreatic elastase, and papain, although subtilisin Carlsberg was strongly inhibited. The amino acid sequence of BGIA shows similarity to potato chymotrypsin inhibitor, barley subtilisin-chymotrypsin inhibitor CI-1 and CI-2, and leech eglin C, especially around the reactive site. Although the residue at the putative reactive site of these inhibitors is leucine or methionine, the corresponding amino acid in BGIA is alanine.

Amino Acid Sequence↗

PubMed1993

Effect of butter, mono- and polyunsaturated fatty acid-enriched butter, trans fatty acid margarine, and zero trans fatty acid margarine on serum lipids and lipoproteins in healthy men.

The effect of diets containing 50% of fat calories from butter, butter enriched with mono- and polyunsaturated fatty acids, and margarines with and without trans fatty acids on the serum lipids of 38 healthy men in a free-living condition have been determined. Serum lipid responses to the high level of individual dietary fats were unexpectedly small. The butter diet produced a small, but significant rise (5%) in the total serum cholesterol and low density lipoprotein (LDL)-cholesterol, relative to all other diets. Enrichment of butter with either olive oil (50/50) or sunflower oil (50/50) failed to reduce serum lipid levels below habitual diet values. Hard margarine, containing 29% trans fatty acids, caused a decrease in apolipoprotein A-I and B levels, but did not change total serum cholesterol or LDL-cholesterol levels, relative to habitual diet values. A soft margarine, high in linoleate, with no trans fatty acids reduced total cholesterol, LDL-cholesterol, and apolipoprotein B significantly, relative to all diets. Soft margarine high density lipoprotein (HDL)-cholesterol levels remained unchanged, but apolipoprotein A-I values were decreased relative to habitual and butter diets. The quantities of saturated fatty acids and the sum of monounsaturated and polyunsaturated fatty acids consumed on the hard and soft margarines were equal; therefore, the different response of serum cholesterol and LDL-cholesterol between these two diets is attributable to the trans fatty acids in the hard margarine. The data indicate that trans fatty acids are not metabolically equivalent to the natural cis isomers and that they affect the serum lipid profile adversely.

Adult↗

PubMed1992

Comparison of the conversion rates of alpha-linolenic acid (18:3(n - 3)) and stearidonic acid (18:4(n - 3)) to longer polyunsaturated fatty acids in rats.

The delta 6-desaturase reaction is regarded to be the rate-limiting step in the conversion of linoleic acid (18:2(n - 6)) to arachidonic acid (20:4(n - 6)). The same is probably also the case with the conversion of alpha-linolenic acid (18:3(n - 3)) to eicosapentaenoic acid (20:5(n - 3)). However, there are very few in vivo studies that directly compared the conversion rate between 18:3(n - 3) and stearidonic acid (18:4(n - 3)), which is the delta 6-desaturated product of 18:3(n - 3). We compared this rate by feeding rats on a lipid-free diet supplemented with lard (9%, w/w) and 18:3(n - 3) ethyl ester (1%) diet or on a diet containing lard (9%) and 18:4(n - 3) ethyl ester (1%). A lard (10%)-supplemented diet was used as the control diet. The fatty acid compositions of total phospholipids, triglycerides and free fatty acids of both liver and plasma were measured after 1 or 3 weeks on different diets. The molar ratio of 20:5(n - 3) of most lipid fractions was about 2-fold higher in rats fed the 18:4(n - 3)-supplemented diet than in rats fed the 18:3(n - 3)-supplemented diet. 18:4(n - 3) was found in the liver lipid fraction in only a very small amount, even in the 18:4(n - 3)-supplemented groups. Thus, desaturation at C-6 is suggested to be the rate-limiting step in the conversion of 18:3(n - 3) to 20:5(n - 3).

Animals↗

PubMed1984

Spectrofluorimetric determination of desoxycholic acid in the presence of cholic and chenodesoxycholic acids by use of Ce(IV) and concentrated sulphuric acid.

A method for the quantitative estimation of desoxycholic acid (200-700 micrograms/ml) in the presence of cholic and chenodesoxycholic acids is described. The method is based on the transformation of desoxycholic acid in fluorescent products (lambda ex = 350 nm, lambda em = 458 nm) by the action of concentrated sulphuric acid, this being enhanced by the presence of Ce(IV). The sample is mixed with a solution of Ce(IV) and concentrated sulphuric acid under standard conditions. Fluorescence is measured in relation to a reference containing the same components except Ce(IV). Cholic and chenodesoxycholic acids do not produce a reaction under adequate conditions. Synthetic samples of bile acids were tested for validation of the method.

Cerium↗