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Biomedical subjects

G Spiteller

Publications and source records attributed to G Spiteller.

At least 37 records · Page 2Linked to original sources
PubMed1988

Investigations of the origin of the furan fatty acids (F-acids).

The possible role of linoleic acid as a biogenetic precursor of the furan fatty acids (F-acids) was investigated in in vivo experiments in the rat, using a C19 analogue of linoleic acid and gas chromatography-mass spectrometry. No evidence of incorporation of this compound into the F-acids was found. Using an improved analysis procedure by converting F-acids into their tetrahydrofuran derivatives (enabling a separation from the large amounts of normal fatty acids), F-acids (F3, F4 and F6) were detected in rat food, correcting earlier results. Quantification of F-acid intake with food and excretion of furandicarboxylic acids in the urine, suggested the possibility that the F-acids are not produced de novo in the rat, but instead accumulate in tissue after nutritional intake.

Animals↗
PubMed1987

Excretion of urinary acids during inverted sleep-waking rhythm.

Some organic acids that occur in human urine are excreted in very different amounts during the day and the night. The day-night rhythm in the excretion rate of citric acid and propylurofuran acid changes only gradually if the normal rhythm of life is inverted, e.g., if a person sleeps during the day and works at night (shift of 12 h), paralleling the gradual adjustment of steroid metabolism under the same conditions. In contrast, the typical rhythm in the excretion rate of tetrahydrofuran acids and tartaric acid inverts immediately if the sleep-waking rhythm of a person is inverted. In contrast to propylurofuran acid, pentylurofuran acid is excreted unrhythmically. No change in the excretion rate of amino acids was observed if the daily rhythm was inverted. Quantifications were achieved by liquid-liquid extraction, derivatization and gas chromatography computerized peak area integration.

Acids↗
PubMed1987

Unusual conjugates in biological profiles originating from consumption of onions and garlic.

After consumption of onions or garlic, biological profiles of human urine samples show, in the methylated conjugate fraction, peaks corresponding to the methylates of N-acetyl-S-(2-carboxypropyl) cysteine (1), N-acetyl-S-allylcysteine (2) and hexahydrohippuric acid (3). The compounds 1 and 2 are metabolites of peptides introduced with onions or garlic into the body.

Acetylcysteine↗
PubMed1987

[Disorders of steroid metabolism in inflammatory skin diseases].

The corticosteroid and androgen metabolites in the urine of 37 test subjects (11 healthy volunteers, 16 patients with eczema, and 10 patients with psoriasis) were investigated by means of gas chromatography and mass spectrometry. In addition, we studied the cortisol and testosterone levels in the plasma by radioimmunoassay. Those patients who had been treated with corticosteroids during the last two weeks were excluded. Our findings revealed that the excretion rate of steroid metabolites was significantly reduced in dermatological patients. The excretion rate of corticosteroids in urine was decreased an average of 25% (eczema) and 29% (psoriasis). The reduction of the androgen metabolites amounted to 26% and 31%. Cortisol and testosterone levels in the plasma were normal in all the cases.

Adrenal Cortex Hormones↗
PubMed1986

Dipeptide analysis in human urine.

Fractions of dipeptides, obtained from human urine by a combination of cation-exchange chromatography, ligand-exchange chromatography and reversed-phase chromatography, were transformed into their N-heptafluorobutyryl methyl ester derivatives and then subjected to capillary gas chromatography. The profiles obtained indicate the presence of many dipeptides in human urine. For the first time, alpha-Asp-Hyp, Pro-Phe and gamma-Glu-Phe were detected in the urine of healthy individuals.

Chromatography, Gas↗
PubMed1986

Changes in the excretion of organic acids in human urine after physical exertion.

The excretion of some acids in urine is subject to a circadian rhythm, if diversified nutrition is offered to the body sufficiently. The effect of physical exertion upon the excretion rates of acids in urine is very similar to that of a zero diet, resulting in an increase of final degradation products and a decrease of metabolic intermediates.

Acids↗
PubMed1986

Influence of topical corticosteroids on hormones in urine and plasma.

In the present study the effects on endogenous hormones of application of topical corticosteroids are investigated. Radioimmunological assays of the hormones cortisol, adrenocorticotrophic hormone (ACTH) and alpha-melanocyte stimulating hormone (alpha-MSH) before, during and after a large-area treatment with topical corticosteroids (30 g/d 0.025% fluocinolone acetonide ointment for 9 days) are performed in eight patients suffering from extensive inflammatory dermatoses (7 cases of eczema, 1 case of psoriasis). Cortisol was measured in plasma daily under treatment. In addition, gas chromatographic and mass spectrometric determinations of urocorticoids and uroandrogens are carried out in 24-h urine. A distinct, treatment-induced suppression of the endogenous steroid production was significant (-42.7%, p less than or equal to 0.05) within the first four days and diminished (-24.4%, p less than or equal to 0.10) after nine days' steroid therapy. The suppression of the plasma ACTH was also significant (-23.1%, p less than or equal to 0.05). The alpha-MSH level did not show any alterations. The measured urocorticoids showed an average fall of -38.9% (p less than or equal to 0.05). It is noteworthy that despite continued steroid treatment the marked initial suppression of the endogenous steroid production diminishes. It is possible that a therapy-induced "normalization" of the epidermis brings about a diminished steroid influx and thus a lower systemic load. Under the therapy conditions chosen here, the androgen metabolites in the urine did not show any significant fluctuations.

Administration, Topical↗
PubMed1985

Gas chromatography of amino acids in urine and haemofiltrate.

Capillary gas chromatography of amino acid derivatives obtained from biological material shows a large number of previously unknown constituents. The profiles of amino acids obtained from urine of healthy individuals and haemofiltrate of uraemic patients indicate that haemofiltration removes some amino acids to a considerably higher extent from uraemic patients than the kidney does from healthy persons. For instance, if haemofiltration is required three times a week, an approximately ten-fold amount of the essential amino acid methionine and a forty-fold amount of the essential amino acid leucine is lost compared to their excretion in urine by a healthy individual over the same period.

Amino Acids↗
PubMed1985

Identification of aromatic dihydroxy acids in biological fluids.

3,5-Dihydroxyphenylpropionic acid, 3,5-dihydroxycinnamic acid and 2,3-dihydroxycinnamic acid were detected for the first time to be components of human urine. In the course of this investigation all constitutional isomers of dihydroxy-benzoic, -phenylpropionic, -phenylacetic and -cinnamic acid were synthesized. Mass spectra and retention indices of methyl and trimethylsilyl (TMS) derivatives were determined. In contrast to many other substituted aromatic compounds the mass spectra of methyl and TMS derivatives of dihydroxy aromatic acids often allow a firm distinction to be made between constitutional isomers: TMS derivatives of aromatic acids containing two hydroxy groups located in the ortho position to each other can be recognized by ions resulting from a primary cleavage reaction mainly in the side chain or ester group, followed by loss of tetramethylsilane. In methyl derivatives of 1,2,3-trisubstituted isomers, methoxy groups are lost much more easily from the ions corresponding to the benzylic cleavage than in other isomers. Methyl derivatives of dihydroxycinnamic acids containing at least one methoxy group in the ortho position to the side chain are characterized by a fragmentation reaction, corresponding to the loss of dimethyl ether. TMS and methyl derivatives of 3,5-dihydroxy aromatic acids show unique structure-specific fragmentation reactions.

Cinnamates↗
PubMed1984

Characterization of artefacts produced by treatment of organic acids with diazomethane.

When alpha, beta-unsaturated acids and alpha-keto acids react with diazomethane not only are the corresponding methylates produced, but also diazomethane is added to the C = C double bond or to the oxo group. The gas chromatographic and mass spectral behaviour of these undesired products and some further artefacts produced in the hot inlet lines of a gas chromatograph are described. The mass spectra and retention indices allowed the structural assignment of several "unknown" compounds found previously in the methylated acid fraction of urine. A detailed analysis of the reaction of alpha-oxo acids with diazomethane revealed that, besides the already known oxirane methyl esters, homologous esters are also produced by an insertion reaction.

Body Fluids↗
PubMed1984

Profiles of strongly polar and less polar acids obtained from human blood, plasma and serum by two-step ultrafiltration.

A two-step ultrafiltration method combined with anion-exchange chromatography is described for the separation of lipophilic and strongly lipophobic acids occurring in human blood, serum and plasma. After treatment with diazomethane, the acid fractions are separated further by gas chromatography. The acids were identified by their mass spectra. Profiles obtained from the strongly acidic fraction of blood samples of healthy individuals are characterized by main peaks corresponding to organic phosphoric acid esters. The peaks are absent in plasma and serum.

Acids↗
PubMed1983

Catabolism of fish furan fatty acids to urofuran acids in the rat.

A mixture of long-chain furan fatty acids was prepared as methyl esters from testes lipids of Northern pike (Esox lucius). Upon feeding these esters to rats, dicarboxylic acids, which still contained the furan structure, were found in the urine. The first phase of a rapid but incomplete catabolism is beta-oxidation of the proximal chain of the furan fatty acids. It proceeds to a distance of three carbon atoms from the ring. omega-Oxidation of the terminal alkyl chain, followed by alpha-oxidation gives rise to a second alkylcarboxyl chain with five carbon atoms or less. The ring methyl substituents of the precursor acids seem to be more resistant to oxidation than the alkyl substituent with three or five carbon atoms. The urinary catabolites from furan fatty acids in the rat are similar to furan acids found in human urine, but only one of the structures occurs in both sources.

Animals↗
PubMed1983

The identification of urinary bile alcohols by gas chromatography-mass spectrometry in patients with liver disease and in healthy individuals.

The neutral steroid fractions in the urine of eleven patients suffering from various forms of liver disease with cholestasis and of ten healthy individuals were studied by glass capillary gas chromatography-mass spectrometry. The steroid conjugates in urine were enzymatically solvolysed, the liberated steroids extracted and transformed into the trimethylsilylether for measurements. The excretion rates of androstane and pregnane metabolites of patients with liver disease were far lower than those of healthy persons. The main compounds in the urine of the former were the bile alcohols 27 - nor - 3 alpha, 7 alpha, 12 alpha, 24 xi, 25 xi - pentahydroxy - 5 beta - cholestane and 3 alpha, 7 alpha, 12 alpha, 25 xi, 26 - pentahydroxy - 5 beta - cholestane. Our data suggest a correlation between the excretion rates of these bile alcohols and the serum levels of bilirubin. While the excretion rate of the two bile alcohols in the urine of healthy individuals was approximately 0.24 mg/24 h (0.6 mumol/24 h) a patient with a serum bilirubin of 841 mumol/l excreted 4 mg/24 h (9 mumol/24 h). The accumulation of bile alcohols described in this study possibly indicates alternative pathways of cholic acid formation in liver disease.

Adult↗