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Biomedical subjects

R Renner

Publications and source records attributed to R Renner.

At least 91 records · Page 5Linked to original sources
PubMed1976

[Volatile phenolic components in beer, smoked beer, and sherry (author's transl)].

Volatile phenolic compounds of beer, wort, smoked beer, and sherry were enriched, separated, identified, and quantified by means of the methods of column chromatography, gas chromatography, and mass spectrometry. The analyzed foods are significantly varying in the composition and quantity of the phenolic components. Four origins of phenolics in food are shown by these results.

Alcoholic Beverages↗
PubMed1976

[Gas chromatographic-mass spectrometric investigations on the formation of phenolic and aromatic hydrocarbons in food (author's transl)].

Phenolic compounds and aromatic hydrocarbons are components in many foods and often typical flavoring substances for example of roasted and smoked products. They are also of toxicological importance. By means of model reactions we have investigated their formation by thermal fragmentation of cinnamic, p-coumaric, ferulic and sinapic acids. The products of these reactions were determined by gas chromatography and identified by mass spectrometry or infrared spectroscopy. Product ratio and mass spectra are given. Barley was roasted in a similar manner, and the components formed were identified. Column chromatography and preparative gas chromatography were used for preliminary separation.

Chromatography, Gas↗
PubMed1975

Effect of partially purified NSILA on adenylate cyclase, phosphodiesterase and 3',5'-cyclic AMP in fat cells.

Partially purified, non-suppressible, insulin-like material (NSILA-S) was studied with respect to its effect on the levels of 3',5'-cyclic adenosine monophosphate (cAMP) and its mechanism of action in the control of this nucleotide in rat fat cells. NSILA-S prevents the rise of cAMP in fat cells under the influence of isoproterenol with similar kinetics to insulin. A maximal effect is observed at about 70 ng/ml with a biological activity equivalent to 200 muU/ml of insulin. NSILA-S inhibits norepinephrine-stimulated adenylate cyclase activity in fat cell ghosts and partially purified plasma membrane preparations. At 10 mM Mg2+, the inhibition is characterized by an effect of Vmax without change in affinity towards ATP (apparent KM 30 muM). Similarly there is no observed change in affinity towards Mg2+. With respect to inhibition of norepinephrine-stimulated adenylate cyclase, the dose-response curve of NSILA-S is similar to that already found with intact cells. The effect of norepinephrine is inhibited throughout the dose-response range between 5 X 10(-7) and 5 X 10(-4) M. In contrast to previous observations with insulin in ghosts, NSILA-S inhibits the basal adenylate cyclase activity. Cyclic nucleotide phosphodiesterase activity in homogenates as measured at 1.0 muM substrate is increased by 90% after previous incubation of fat cells with NSILA-S. The study suggests that the anti-lipolytic effect of NSILA-S is mediated by a lowering of cAMP through inhibition of the adenylate cyclase and/or stimulation of the phosphodiesterase system.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1975

Re-evaluation of Sepharose-insulin as a tool for the study of insulin action.

The biological activity of Sepharose-insulin in different assays in vitro, e.g., stimulation of glucose oxidation, lipogenesis, and antilipolysis and activation of pyruvate dehydrogenase (EC 1.2.4.1) activity, has been investigated. According to amino acid analysis, between 270 and 330 mug (6.9-8.2 U) of insulin were coupled per ml of packed beads. Related to the total insulin content, 0.2-0.7% of the insulin was biologically active. Comparable biological activity was observed with isolated fat cells and fat pad pieces. After incubation with tissue or cells, Sepharose-insulin particles were separated by centrifugation from the medium. The clear supernatant was assayed for biologically and immunologically reactive insulin and contained soluble insulin activity. A quantitative evaluation of the soluble biological and immunological insulin activity in the supernatant accounted for the total insulin activity of Sepharose-insulin.

Adipose Tissue↗