Identification of fatty acid methyl esters (FAMEs) in postmortem tissue. A new marker of alcohol abuse?

Based on a method that combines thin layer chromatography and gas chromatography, it proved possible to detect postmortem fatty acid methyl esters (FAMEs) in human tissues (pancreas, liver, heart and adipose tissue). The highest concentrations were found in the pancreas, medium concentrations in the liver and adipose tissue and the lowest concentration in heart tissue. All tissues contained higher concentrations of unsaturated FAMEs than saturated FAMEs. In order to evaluate the influence of alcohol consumption on the formation of FAMEs, the decreased were divided into three groups: control group, chronic alcoholics (who were alcohol free at the time of death), and acutely alcohol-intoxicated subjects (so intoxicated at the time of death with no evidence of chronic alcohol abuse). In comparison to the control group, the organs of the chronic alcoholics showed only slight values, the tissues of the acutely intoxicated subjects were obviously higher. Based on the varying concentration distribution in the three groups, it seemed that postmortem differentiation of the alcohol consumption which existed before the time of death would be possible. After further investigation with a greater number of samples, FAMEs could become a useful supplement to existing alcohol markers in the future.

5-hydroxyquinoline-2-carboxylic Acid, a dead-end metabolite from the bacterial oxidation of 5-aminonaphthalene-2-sulfonic Acid.

5-Aminonaphthalene-2-sulfonate (5A2NS) is converted by strain BN6 into 5-hydroxyquinoline-2-carboxylate (5H2QC). The authenticity of this new compound is confirmed by nuclear magnetic resonance and mass spectrometry. Its formation is explained by a spontaneous cyclization of the hypothetical metabolite 6'-amino-2'-hydroxybenzalpyruvate. The formation of 5H2QC as a dead-end product of 5A2NS prevents NADH regeneration so that 5A2NS oxidation is limited by the internal NADH pool.

Identification of oestrogen metabolites in human urine by capillary gas chromatography and mass spectrometry.

Oestrogen metabolites from the urine of males and pregnant and non-pregnant females were enriched by a procedure involving column chromatography on adsorber resins, gels and ion exchangers, enzymatic solvolysis and extraction, thereby separating the oestrogens from most of the interfering material. After derivatization of the oestrogens as their trimethylsilyl ethers profiles were measured with a fused silica column and a flame ionization detector by gas chromatography. Using a combination of capillary gas chromatography and mass spectrometry approximately 50 oestrogen metabolites were detected in the human urine of males and females, of which 19 were unknown urine compounds. Not all could be identified definitely owing to the lack of reference material. Mass spectra of trimethylsilylated oestrogens with functional groups at position 11 (11-dehydroestradiol, 11-dehydroestrone and 11 beta-hydroxyestrone) were discussed in their common and discernible fragmentations.

[Large droplet lipids in blood in the right ventricle]. / Grosstropfiges Fett im Blut des rechten Ventrikels.

In several cases of fatal blunt-trauma injuries or after exposure to severe burning, large-drop fatty substances, discernible to the naked eye, were found in the venous blood of the right ventricle. Thin-layer chromatographic separation of the extracted lipids demonstrated an increase in the triglyceride fraction. Analysis of the fatty acids by means of combined gas chromatography/mass spectrometry showed a shift towards oleic acid. The distribution pattern of the molecular weights was determined by means of DCI-mass spectrometry in order to characterize the triglycerides in detail. The total chemical findings indicated that the visible lipids present in the right ventricle had predominantly derived from the adipose tissues. In cases of post mortem burning (without vital traumata) no typical pulmonary fat embolism had developed despite massive lipemia in the venous blood.

Chemical structure and biodegradability of halogenated aromatic compounds. Halogenated muconic acids as intermediates.

Substituted muconic acids were prepared from the corresponding catechols by pyrocatechase II from Pseudomonas sp. B13. The stabilities of substituted muconic acids were compared under different pH conditions. 3-Substituted cis, cis-muconic acids cycloisomerized readily in slightly acidic solutions, whereas 2-chloro- and 2-fluoro-cis,cis-muconic acids were stable under these conditions and could be isolated as crystalline compounds. They were isomerized to the cis, trans-form in highly acidic solution (pH 1), particularly when heated to 80 degrees C. Cycloisomerization of 2-chloro-cis,cis-muconic acid in 75% (v/v) H2SO4 yields 4-carboxymethyl-2-chloro-but-2-en-4-olide (4-chloro-2,5-dihydro-5-oxo-3H-furan-2-ylacetic acid). THe cis,cis-configuration of 2-chloromuconic acid was certified by 1H n.m.r. spectroscopy and by enzymic cycloisomerization. Although the cis,cis-configuration of 2-fluoromuconic acid was confirmed by corresponding spectroscopic data, it was not cycloisomerized by crude extracts or cycloisomerase II preparations from Pseudomonas sp. B13.

Mass spectrometric identification of DL-verapamil metabolites.

DL-verapamil [2,8-bis(3,4-dimethoxyphenyl)-6-methyl-2-isopropyl-6-azaoctanitrile; Isoptin] is metabolized in man by N-dealkylation -- mainly by cleavage of the N6-C7 bond -- and by demethylation of the methoxy groups. After oral administration, besides unchanged verapamil, 12 metabolites could be isolated from urine and their structures were elucidated by (GC-) mass spectrometry.

The metabolism of DL-[14C]verapamil in man.

The metabolism of DL-verapamil in man was studied after oral administration of an aqueous solution of DL-[14C]verapamil. Between 67 and 71% of the 14C administered was excreted in the urine within 5 days. Verapamil was extensively metabolized; only 3--4% of the dose was excreted in the urine as unchanged drug. Cleavage of the C--N--C bond by N-'dealkylation, preferentially at the C-atom belonging to the shorter side chain, was the main metabolic step. Verapamil and its N-dealkylated metabolites were further metabolized by O-demethylation. Inasmuch as approximately 10 times more of the metabolites formed from the tertiary amine verapamil are secondary amines than are primary amines, it would seem that N-dealkylation of this tertiary amine proceeds at a much higher rate than the N-dealkylation of the secondary amine metabolites to primary amine metabolites.

Urinary metabolites of clomethiazole. Detection and structural analysis by gas chromatography-mass spectrometry.

As the result of a renewed extensive investigation of clomethiazole (Distraneurin) metabolism five previously unknown metabolites could be isolated from human urine. Their structures were elucidated by mass spectrometry. Whereas previous investigations on the metabolism of clomethiazole had demonstrated changes only of the ethyl group, we now found metabolites attached to the methyl group, too. The newly isolated compounds 5-(1-hydroxy-2-chloroethyl)-4-methylthiazole (9) and 5-(2-hydroxyethyl)-4-thiazole carboxylic acid lactone (5) were found to be more abundant in human urine than 4-methyl-5-thiazole acetic acid previously considered as the main metabolite.

Metabolism of DL-[14C]prenylamine in man.

Following oral administration of DL-[14C]prenylamine, about 40% of the dose administered was excreted in urine within 10 days. Less than 0.1% of the dose was excreted as unchanged prenylamine. The drug was extensively metabolized to at least 20 to 25 metabolites. The structure of 12 metabolites could be elucidated by means of g.c.m.s. Ring hydroxylation and further methylation of the phenolic metabolites are the main metabolic pathways involved. A substantial part of the drug and/or its metabolites is metabolized via cleavage of the C--N--C bond, giving rise to amphetamine and diphenylpropylamine which are further metabolized by aromatic and sidechain hydroxylation.

Quinine-N-oxide--a urinary component after the consumption of quinine beverages.

After the consumption of quinine-containing beverages, quinine-N-oxide could be identified in the urine mass spectrometrically. Consequently in the analysis of physiological fluids for drugs not only the drugs themselves must be considered but also their metabolites.