Formation of Enol Ether Epoxides by Reaction of (9S,1OE,12Z)-Hydroperoxyoctadecadienoic Acid with Plasmalogens(9S,10E, 12Z)-Hydroperoxyoctadecadienoic acid (8a) oxidizes enol ethers (e.g. 2 and neutral plasmalogens 3) under physiological conditions (pH = 6.6, room temperature). The reaction products, unstable enol ether epoxides 9a and 10a, react as recently demonstrated['l with methanol to a-hydroxyaldehyde dialkyl acetals l l a or with 1,2-ethanedithiol to 2-(a-hy-droxyalky1)dithiolans 13a which can be detected by G U M S after trimethylsilylation. If ['802]-(9S,10E,12Z)-hydroperoxyoctadecadienoic acid (8b) is used instead of 8a one atom of " 0 is incorporated into the enol ether epoxide and found in the a-hydroxy group of the aldehyde derivatives 11 and 13.Kiirzlich zeigten wir, daD die Enolether 1 und 2 in alkoholischer Losung beim Ruhren an der Luft zu den a-Hydroxyaldehyd-dialkylacetalen 5 bzw. 6 oxidiert werden"], allerdings nur in Mengen, die gerade noch mittels G U M S nachweisbar sind. Schema I . Bildung der gemischten Acetale 5-7 durch Oxidation der Enolether 1-4 OCH, 0,. CH,OH I R ' -O -C H -C H -R~ -R' -0 -CH -CH -R~ I 1-4 5-7 OH I R' R2 Alkyl OAcyl 7 I -OH OH Alkyl R3 = Phosphatidylethanolarnin, -cholin Zusatz von (9Z, 12Z)-Octadecadiensaure (Linolsaure) erhoht die Ausbeute an 5 und 6 erheblich[Il. Diese Beobachtung legt nahe, daD das oxidierende Agens entweder ein Hy-droperoxid der Linolsaure (LOOH) oder ihr Hydroperoxyradikal (LOO') ist. Schema 2. (9S, 1 OE, 12Z)-HydroperoxyoctadecadiensHuren 8a. b x , H C5HIl A [CH,],-COOH 8a,b 8 1 a b X I HO, H"0, Enolether kommen in tierischen und menschlichen Zellen als Neutral-3 und Phospholipid-Plasmalogene 4 vor. Analoge Reaktionen laufen daher wahrscheinlich auch im Korper ab. a-Hydroxyaldehyd-dialkylacetale 7 sind nach Aufarbeitung von Gewebe nachweisbar[ll. In dieser Arbeit zeigen wir, daD langkettige a-Hydroxyaldehyde durch Einwirkung von (9S, 10E, 123-Hydroperoxyoctadecadiensaure [(9S)-LOOH, 8a] auf Enolether 2 oder Neutralplasmalogene 3 entstehen konnen, allerdings in Abwesenheit von Katalysatoren nur in Ausbeuten von etwa 0.1%. Linolsaure wird bei Zellverletzung aus linolsaurehaltigen Lipiden, Bestandteilen von Membranen, freigesetzt und durch Lipoxygenasen in (9S, 1 OE, 12Z)-Hydroperoxyoctadecadiensiure iibergefuhrt[21. Als Modellverbindung wurde zunachst 1 -Decenylpentylether 2[3.41 mit (9S)-LOOH 8a in Phosphatpufferlosung (pH = 6.6) bei Raumtemperatur versetzt. (9S)-LOOH (8a) wurde nach einer modifizierten Vor~chrift[~.~l aus Linolsiure durch Zusatz von Tomatenhomogenisat gewonnen. Nach 20 h wurde das als Zwischenprodukt entstandene in-

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Diepoxides of linolenic acid were found to be chemoattractants. The concentration that produces 50% of maximal chemotaxis was 4.5 10-7 mol/l for human neutrophils when investigated in a chemotaxis test based on the method of spectrophotometric determination of myeloperoxidase activity with buffers containing bovine serum albumin. Leukotriene B4 was used as positive control. The concentration of leukotriene B4 that produces 50% of maximal chemotaxis was 1.8 nmol/l. No chemotactic activity was observed when monoepoxides of linoleic or linolenic acid, diepoxides of linoleic acid or triepoxides of linolenic acid were used. Mono-, di-and triepoxides of polyunsaturated fatty acids were synthesized with meta-chloroperbenzoic acid, separated by TLC and HPLC and identified by GC/MS.

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Ethylene Oxide, M etabolism of Ethylene Oxide, Thiodiacetic Acid, GC/MS Urine samples of premature babies contain high amounts of thiodiacetic acid (TD A). Since these pre-term infants are exposed to an increased oxygen atmosphere in the incubator, we supposed that these high levels of thiodiacetic acid might be produced from ethylene, gener ated in the course of lipid peroxidation processes. Considering that conversion of ethylene to ethylene oxide (E O ) is well known in biology we investigated whether ethylene oxide is metabolised to thiodiacetic acid or not. Therefore Sprague-Dawley rats and NMRI mice were exposed to ethylene oxide for six hours. Urine specimens were collected after exposure and the amount of thiodiacetic acid was determined by gas chromatography/mass spectrome try. The quantity of excreted T D A increased enormously compared to control samples. So thiodiacetic acid seem s to be a metabolite o f ethylene oxide in vivo. IntroductionAny human urine specimen contain a basic level of thiodiacetic acid (Müller et al., 1978). A dra matic increased excretion of TDA was observed in neonatal urine of premature babies, delivered in gestation week 25-30 (Pettit et al., 1984). In both cases the precursor molecules of urinary TDA re mained unknown until now.Thiodiacetic acid is a well known metabolite of some medicines and various small reactive mole cules. Many 1,2-disubstituted ethane derivatives, e.g. 1,2-dichloroethane (Payan et al., 1993), 2-bromoethanol (Jones and Wells, 1981) and 2-chloroethanol (Grunow and Altman, 1982) to S-carboxymethyl cysteine (Müller and Norpoth, 1977;Müller and Norpoth, 1978) which finally leads to thiodiacetic acid (Yllner, 1971;Müller et al., 1976;Müller and Norpoth. 1978).S-carboxymethyl cysteine was also reported to be a metabolite of ethylene oxide (EO), another reactive C-2 compound (Tardif et al., 1987). The metabolism of ethylene oxide was studied rather intensively (Segerbäck, 1983 (Abeles and Dunn, 1985) as well as rat liver microsomes (Schmiedel et al., 1983) are able to produce ethyl ene oxide by epoxidation of ethylene. Therefore rats exposed to ethylene exhaled EO (Filser and Bolt, 1983).Ethylene is generated from co-3 polyunsaturated fatty acids in mammalians (Dumelin and Tappel, 1977) and also released during lipid peroxidation from peptides containing methionine (Scheick and Spiteller, 1996). Pre-term infants exposed to an increased oxygen atmosphere in the incubator often suffer from retrolental fibroplasia caused by oxidative stress (Bast, 1989). Therefore we pre sumed that the high TDA levels in urine speci mens of premature babies might be due to the me tabolism of ethylene to TDA, via ethylene oxide, in the course of increased lipid peroxidation. To confirm this assumption we exposed rats and mice to ethylene oxide and checked their urine speci mens for thiodiacetic acid. Materials and Methods Chemicals50 1 of 1.01% ethylene oxide (CAS-no. 7 5 -2 1 -8 ) in nitrogen were obtained from Messer Griesheim (Düsseldorf, Germany). All other chemicals we...