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Biomedical subjects

O Beck

Publications and source records attributed to O Beck.

At least 127 records · Page 7Linked to original sources
PubMed1979

On the occurrence of 5-methoxytryptamine in brain.

A quantitative gas chromatography-mass spectrometry method has been used to determine 5-methoxytryptamine (5-MT) in the CNS and pineal gland of various species. The mean +/- S.D. levels of 5-MT in sheep, pig and cow pineal glands was 545 +/- 180, 228 +/- 119 and 117 +/- 48 pmol/g, respectively. The postmortem levels of 5-MT in the pig pineal gland was stable for 2 h after death but decreased by more than 90% 24 h after death. In the CNS, 5-MT was found only in the sheep hypothalamus (28 +/- 4 pmol/g). Analysis of the rat pineal gland and CNS failed to detect any 5-MT at the limit of sensitivity of the method which is at variance with previously reported results.

5-Methoxytryptamine↗
PubMed1979

Analysis of 5-methoxytryptamine in brain by gas chromatography mass spectrometry.

A quantitative gas chromatographic mass spectrometric method using a deuterated analogue as internal standard were developed for the analysis of 5-methoxytryptamine in brain. The internal standard was synthesized in two steps and possessed high isotopic purity. The analytical procedure involves the addition of the internal standard to the homogenizing medium containing the tissue, followed by homogenization, extraction with chloroform and derivatization with pentafluoropropionic anhydride. The identification and quantitation of 5-methoxytryptamine is based on monitoring the ions at m/z 306, 319 and 482 for the pentafluoropropionyl derivative of 5-methoxytryptamine and m/z 308, 322 and 486 for the internal standard. Using this procedure 5-methoxytryptamine was identified and quantitated in the sheep pineal gland. The mean 5-methoxytryptamine level (N = 12) was 545 +/- 180 pmol g-1.

5-Methoxytryptamine↗
PubMed1977

Quantitative determination of 5-hydroxyindole-3-acetic acid in body fluids by high-performance liquid chromatography.

A method for the quantitative determination of 5-hydroxyindole-3-acetic acid in urine and cerebrospinal fluid is described. The method is based on reversed phase high-performance liquid chromatography and fluorometric detection. The experimental error was below 5% in urine and 8% in cerebrospinal fluid. Urine and cerebrospinal fluid samples were analysed both by the described method and by a mass fragmentographic method. The correlation coefficients for the two methods were 0.986 in the urine samples and 0.965 in the cerebrospinal fluid samples. Analysis of 100 samples can be achieved within 3 days. The described method offers a possibility to determine 5-hydroxyindole-3-acetic acid in urine and cerebrospinal fluid with the same precision and capacity as do mass fragmentography but with the use of a less sophisticated equipment.

Chromatography, High Pressure Liquid↗
PubMed1977

Mass fragmentographic determination of 5-hydroxytryptamine and 5-hydroxyindole-3-acetic acid in brain tissue using deuterated internal standards.

A mass fragmentographic method for the determination of 5-hydroxytryptamine (5-HT) and 5-hydroxyindole-3-acetic acid (5-HIAA) in the same extract of rat brain tissue is decribed. Deuterium-labelled analogues were used as internal standards. 5-HT and 5-HIAA were separated by solvent extraction and pentafluoropropionyl derivatives were prepared for the mass fragmentographic analysis. Multiple ion analysis confirmed the identity of 5-HT and 5-HIAA in the rat brain. At the mass numbers used routinely for the determination of 5-HT and 5-HIAA in the rat brain. At the mass numbers used routinely for the determination of 5-HT and 5-HIAA, the experimental error was below 3% (calculated from mean values of 0.05 and 0.24 nmole, respectively). The recovery of the authentic compounds added to brain extracts was more than 95%. The levels of 5-HT and 5-HIAA in the rat brain were 2.95 +/- 0.16 and 0.64 +/- 0.18 nmole/g, respectively. More than 100 samples could be analyzed within 3 days. The presence of 5-hydroxytryptophol in rat brain was also investigated, but none could be detected either as a conjugate or as the free alcohol.

Animals↗
PubMed1977

Continuous measurement of the oxygen tension in blood. A comparative study in the dog.

An equipment constructed by the International Biophysics Corporation, the Differential Oxygen Analyzer, which was designed for continuous recording of the oxygen tension in the blood, particularly during extracorporeal circulation, was tested. It proved to react rather slowly to changes in the PO2 and the magnitude of the error of the single measurements is far too high at the present stage of development.

Animals↗
PubMed1976

[Preservation of articular cartilage. 1. Chondrocyte vitality depending on the preservation method (autoradiographic studies)].

Vitality of chondrocytes of articular cartilages of adult Alsatian dogs was autoradiographically examined in vitro after different kinds of preservation. All preserving methods that require freezing-in result in dying of cartilage cells, immediately or after one day. On the other hand, chondrocytes survive dry preservation at +4 degrees C. for 14 days, and even for 28 days when stored in 5 per cent glucose solution.

Animals↗
PubMed1976

[Preservation of articular cartilage. 2. Behavior of glycosaminoglycans (GAG) in the intracellular substance of preserved articular cartilage (histo- and biochemical studies)].

Glucosaminoglucanes (acid mucopolysaccharides) were assessed by means of histochemic and biochemic methods in differently preserved articular cartilages of adult Alsatian dogs. Immediately after lyophilization, resp. 14 days after preservation at --196 degrees C., the glucosaminoglucanes decrease, whereas they are present in undiminished concentration after deep-freezing preservation (--18 degrees C. and --78 degrees C.) up to 30 months, and at +4 degrees C. up to 100 days. No more destruction of glucosaminoglucanes occurs after dying of chondrocytes, obviously depending on blocking the glucosaminoglucanes destructing enzymes during the freezing. With regard to the investigations on the vitality, deep-freezing preservation at --18 degrees C. to --78 degrees C. is recommended for storage of avital articular cartilage. Preservation of vital articular cartilage is possible for 28 days at +4 C. in 5 per cent glucose solution.

Animals↗