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Biomedical subjects

M Strassner

Publications and source records attributed to M Strassner.

6 recordsLinked to original sources
PubMed2001

Comparative investigation of human stratum corneum ceramides.

The stratum corneum (SC) requires ceramides, cholesterol, and fatty acids to provide the cutaneous permeability barrier. SC lipids can be analyzed by normal-phase high-performance thin-layer chromatography (HPTLC). However, without further analysis, some uncertainty remains about the molecular composition of lipids represented by every TLC band of an unknown sample. We therefore analyzed each ceramide band further by subjecting the isolated lipids to a direct coupling of reversed-phase high-performance liquid chromatography and electrospray ionization-mass spectrometry (HPLC/ESI-MS, or LC/MS). LC/MS analysis and ESI-MS/MS negative ion and collision-induced dissociation experiments revealed that ceramide band 4 contained not only N-(omega-OH-acyl)acyl-6-OH-sphingosine, Cer(EOH), but also N-(alpha-OH-acyl)-sphingosine. Band 5 exclusively contained N-acyl-6-OH-sphingosine. Our results demonstrate the benefit of LC/MS analysis for selective identification of human SC ceramides. Moreover, the combination of HPTLC for pre-separation and LC/MS for identification of lipids is an even more powerful tool for detailed ceramide analysis.

Ceramides↗
PubMed1992

Determination of moxonidine (BDF 5895) in plasma by gas chromatography-negative ion chemical ionization mass spectrometry.

For the measurement of the pharmacokinetic behaviour of moxonidine, 4-chloro-5-(2-imidazolin-2-yl-amino)-6-methoxy-2-methylpyrimidine, an extremely sensitive analytical method was needed. The GC-MS method developed is specific and reliably detects moxonidine plasma levels down to 40 pg ml-1. Using negative ion chemical ionization (NICI) the M- fragment of the ditrifluoromethyl benzamide derivative of moxonidine (m/z 721) and the [M-HCl]- fragment of the ditrifluoromethyl benzamide derivative of clonidine (internal standard, m/z 673) were monitored in the selected ion monitoring mode, ensuring a specific and sensitive detection of the compounds. The validation process carried out included assay precision, repeatability, linearity, accuracy, stability and estimation of the detection and determination limits. The plasma-level time-curves and pharmacokinetic parameters from two volunteers after oral administration of 0.2 mg moxonidine are presented and demonstrate the practicability of the method in, for example, clinical studies.

Antihypertensive Agents↗
PubMed1987

[Heart disease and pregnancy--results of consequent interdisciplinary management].

In this paper it has been published about the interdisciplinary cooperation during the treatment of 143 pregnant women having heart diseases. In spite of a partial centralisation this number only 0.46 per cent of all deliveries in a period of 16 years. 32.1 per cent of the cases are congenital heart diseases and 46.2 per cent acquired heart diseases. In the acquired heart diseases mitral failures prevailed. Pacemakers have to be applied preventively only in 6.3 per cent. NYHA-stages did not impair during pregnancy. Vaginal operative delivery is compulsory only in two of seven cases heart diseases indicated a cesarean section. Consequent early get-up in the puerperium is important in NYHA-stages I-III. Maternal mortality was 0. Perinatal mortality was 0.7% (one child died antenatally).

Cesarean Section↗
PubMed1978

Studies on the metabolism of steroid hormones in a virilizing adrenal cortex adenoma.

Slices of an adreno-cortical adenoma which had been obtained at operation from an 11-year-old girl with clinical signs of virilism were incubated with each of the following steroids: [1,2-3H]progesterone, [4-14C]pregnenolone, [1,2-3H]testosterone, [4-14C]androstenedione and [7-3H]dehydroepiandrosterone, respectively. Isolation and identification of the free radioactive metabolites were achieved by gel column chromatography on Sephadex LH-20, thin-layer chromatography, radio gas chromatography and isotope dilution. After incubation of progesterone, the following metabolites were identified: 11beta-hydroxyprogesterone, 16alpha-hydroxyprogesterone, 17alpha-hydroxyprogesterone, 21-deoxycortisol, corticosterone and cortisol. Pregnenolone was metabolized to 17alpha-hydroxypregnenolone, progesterone, dehydroepiandrosterone, androstenedione and 11beta-hydroxyandrostenedione. When testosterone was used as substrate, 11beta-hydroxytestosterone, androstenedione and 11beta-hydroxyandrostenedione were found as metabolites, whereas androstenedione was metabolized to testosterone and 11beta-hydroxyandrostenedione. After incubation of dehydroepiandrosterone, only androstenedione and 11beta-hydroxyandrostenedione were isolated and identified. From these results, it appears that cortisol was formed in the adenoma tissue via 21-deoxycortisol and corticosterone. Delta4-3oxo steroids of the C19-series arose exclusively from pregnenolone via 17alpha-hydroxypregnenolone and dehydroepiandrosterone, and not from progesterone and 17alpha-hydroxyprogesterone. Calculated on the amounts of metabolites formed, the highest enzyme activities were those of the 11beta-hydroxylase and the 17alpha-hydroxylase. It is interesting to note that only traces of testosterone were detected after incubation of androstenedione, whereas testosterone yielded large amounts of androstenedione.

Adenoma↗
PubMed1975

Gel chromatography of steroid oestrogens on sephadex LH-20.

The behavior of 23 steroid oestrogens Sephadex LH-20 using six solvent systems was investigated. The fractions eluted by gel column chromatography were analysed by thin-layer chromatography and spectrometry. The method was used for the radiochemical purity of labelled compounds by isotopic dilution.

Chromatography, Gel↗