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Biomedical subjects

G Spiteller

Publications and source records attributed to G Spiteller.

At least 91 records · Page 5Linked to original sources
PubMed1980

Occurrence of highly oxygen-substituted androgens in hemofiltrates of uremic patients.

The steroid fraction of hemofiltrate contains a large number of unknown steroids, which were separated by a combination of different chromatographic procedures and finally characterized by gas chromatography mass spectrometry. Besides different isomeric 3,16,17-trihydroxyandrostanes in a rather polar fraction a 3,16,17-trihydroxy-11-ketoandrostane was detected, obviously the first naturally occurring representative of 3,11,16,17-oxygen-tetrasubstituted androstanes.

Androstanes↗
PubMed1979

[Separation and characterization of acidic urine constituents (author's transl)].

The acidic compounds of urine were separated by thin-layer chromatography in eight fractions. Each fraction was investigated separately by the combination glass capillary gas chromatography-mass spectrometry. About 500 compounds were detected, 2/5 of these could be characterized by their mass spectra. Retention data and key fragments of the mass spectra were tabulated. Many of the detected compounds are still unknown.

Carboxylic Acids↗
PubMed1979

[Occurrence of alpha-alkyl-substituted malic acids, and beta-hydroxy-beta-alkyl-substituted dicarboxylic and tricarboxylic acid derivatives in normal urine (author's transl)].

Urine contains a number of alpha-hydroxy acids so far unknown to occur in biological liquids. Besides the already as urine constituent known methylmalic acid, also the ethyl, isopropyl and butyl derivatives of malic acid were found. Further metabolites in urine are a beta-propyl-substituted beta-hydrosyglutaric acid, a beta-hydroxy-beta-[methyl-carbomethoxy]-adipinic acid and two isomeric alpha-methylcitric acids.

Esters↗
PubMed1979

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.

Biotransformation↗
PubMed1979

[Metabolism of antiparkinson drugs. An example of competitive hydroxylation].

The investigation of the metabolism of the antiparkinson drugs trihexyphenidyl (1), pridinol (2) and biperiden (3) revealed a graduate tendency for hydroxylation in the different structural elements: If alicyclic, saturated heterocyclic and aromatic ring systems are present in one compound like in 1, the alicyclic ring system is attacked predominately. The amount of metabolites with hydroxy-groups in the saturated heterocyclic ring is much lower, and no hydroxylation takes place in the aromatic ring. In drugs without alicyclic ring systems like 2 the saturated heterocyclus is attacked preferentially, but also some phenolic metabolites are formed. Consequently the following arrangement of falling hydroxylation-tendency can be established: Formula: see text. Probably this arrangement is of common validity and therefore a prediction on the hydroxylation-tendency of other compounds seems to be possible.

Adult↗
PubMed1978

[Profiles in chronic diseases. I. Investigations of steroid profiles in uremia (author's transl)].

Steroid profiles of hemofiltrates of uremic patients contain as main steroids the sulfates of 11beta-hydroxyetiocholanolone, 11-ketoetiocholanolone, 11beta-hydroxyandrosterone and 11-ketoandrosterone. In blood of uremic patients androstenediol is the main steroid of the sulfate fraction, while in blood of healthy persons dehydroepiandrosterone sulfate is the main steroid. The gradual decrease of the kidney function is characterized by an increase of 11-oxigenated androstane conjugates in urine.

Androstenediols↗
PubMed1978

[Urine steroid profiles of hirsute women (author's transl)].

Steroid profiles of women suffering from idiopathic hirsutism show in more than 50% of the cases of 10--100 fold increase in the excretion of dehydroepiandrosterone (DHEA) compared with normal values. The excretion of DHEA was reduced much more than that of other 17-ketosteroids if the adrenals (NNR) were suppressed by dexamethasone (DXM). Within one week they reached values at the compound noise level of the gas chromatograms. If the ovaries were stimulated with human chorionic gonadotropin during continued suppression of the NNR with DXM no increase of DHEA could be detected.

17-Ketosteroids↗
PubMed1978

[On the metabolism of antipyrine (phenazone) in man (author's transl)].

The metabolism of antipyrine (phenazone) was studied by means of C14-antipyrine labelled at C-3. Besides the metabolites already known two conjugates were isolated and characterized by their mass spectra. The occurrence of 2-hydroxymethyl-3-methyl-1-phenyl-3-pyrazolin-5-one and 3,4-dihydroxy-2,3-dimethyl-1-phenyl-pyrazolidin-5-one could not be confirmed, although 95% of the radioactivity administered was recovered.

Antipyrine↗
PubMed1977

Location of functional groups in antipyrine metabolites by mass spectrometry.

The mass spectra of antipyrine metabolites show characteristic fragmentation patterns which depend on the presence and position of functional groups. A substituent at position 4 is indicated by an intense key fragment at m/e 56 and a substituent at the methyl group in position 3 causes a significant increase in the intensity of the peak at m/e 82. The fragment at m/e 96, which is characteristic for antipyrine itself, is suppressed if there is a substituent in either position 3 or 4. Mass spectra of the glucuronides of 4-hydroxyantipyrine and 3-hydroxymethylantipyrine are also discussed.

Antipyrine↗
PubMed1977

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.

Adult↗
PubMed1977

[Exchange of aromatically bound halogen for OH- and SCH3-groups in metabolising clozapine in the human organism (author's transl)].

8-Chloro-11-(4-methyl-1-piperazinyl)-5H-dibenzo-(b,e)(1,4)-diazepine (clozapine, 1) is metabolized in humans by exchange of the aromatic halogen for a hydroxy- or a methylthio-group (compounds 2 and 3). Further metabolites are the N-demethyl derivatives of 2 and 3, the compounds 4 and 5. In addition a clozapine metabolite with the structure 6 with an oxidized piperazine ring was found. The presence of a metabolite with an oxidized sulfur atom is suggested. Possible ways for the formation of these metabolites are discussed.

Clozapine↗
PubMed1975

[Use of spectroscopic methods in drug analysis].

The use of spectroscopic methods (IR, NMR, MS) for the investigation of drugs is demonstrated. Due to the high sensitivity mass spectrometry in combination with glass capillary gaschromatography seems to become in many cases the method of choice. The use of computers which are able to determine with the aid of key fragments partial structures of unknown metabolites will be a very promising technique in the the future.

Chromatography, Gas↗