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Biomedical subjects

H Esterbauer

Publications and source records attributed to H Esterbauer.

At least 199 records · Page 11Linked to original sources

[Isomeric trihydroxy-octadecenoic acids in beer: Evidence for their presence and quantitative determination (author's transl)].

Evidence is presented that beer contains the following isomerric trihydroxy acids: 9,12,13-Trihydroxy-10 trans-octadecenoic acid (G1), 9,10,13-Trihydroxyl-11 trans-octadecenoic acid (G2), and 9,10, 11-Trihydroxy-12 trans-octadecenoic acid (G3). The compounds were isolated from a CHCl3: MeOH extract of beer by column chromatography and their structures determined by comparison of their mass spectra, Rf-values (TC) and retention times (GC) with the data obtained with the reference compounds G1, G2, and G3 prepared by enzymic oxidation of linoleic acid with barley flour. For the quantitative determination a CHCl3: MeOH extract of 100 ml acidified beer was methylated, silylated and separated by GC. Depending on the specific beer source, the beer contained 4.7--9.0 mg/1 G1, 1--2.4 mg/1 G2 and 0.4--0.7 mg/1 G3. The mechanism of the formation of these compounds from linoleic acid is discussed as well as their possible contribution to the stale flavor of beer which develops upon prolonged storage.

Beer↗

[Adrenaline application by intraperitoneal depot capsule -- effects in the heart (author's transl)].

An intraperitoneal depot capsule was developed to improve the hitherto used in vivo test methods for chronic action of water soluble substances (repeated injections or permanent infusion which immobilizes the experimental animals). The capsule allows free movement of the animal and guarantees long-term continuous output of the substance. The effectiveness of the capsule was examined using adrenaline as test substance. In these experiments the maximum period of effectiveness and the consequences of permanent occupation of the receptors due to continued supply of adrenaline were studied.

Animals↗

[Binding of cortisol, fluocortolone and difluocortolone to human plasma proteins (author's transl)].

The binding properties of [3H]cortisol, [3H]fluocortolone and [3H]difluocortolone by human plasma, human albumin, human- beta- and gamma-globulins have been studied by equilibrium dialysis. Cortisol, in physiological concentrations (0,4 micromol/l), is 98% bound in human plasma at 25 degrees C, fluocortolone 96% and diflucortolone 85%. Uncer physiological conditions cortisol is mainly bound to the corticosteroid binding globulin (transcortin). 2/3 of fluocortolone is bound to transcortin and 1/3 to albumin and globulins, whereas difluocortolone is mainly bound to albumin and to globulins but not to transcortin. The binding affinities of beta- and gamma-globulins are -ery low for the corticoids investigated, but they are higher for fluocortolone and difluocortolone than for cortisol.

Carrier Proteins↗

[Relationship between Chemical Constitution and Theraeutic Activity of alpha, beta-unsaturated Aldehydes in the Ehrlich-Solid-Tumor of the Mouse].

Biochemical and biological effects and chemical properties of three alpha,beta-unsaturated aldehydes [acrolein (I), 4-hydroxypentenal (II), and 4-hydroxyundecenal (III)] were compared. These three substances inhibited the incorporation of -3H-thymidine in Ehrlich-ascites-tumor cells in vitro in the following order: I is greater than III is greater than II. For reactivities with glutathion in vitro the order was: I is greater than II is greater than III is greater than. We concluded there from that the high activity of I, as to its inhibition of thymidine incorporation and its toxicity, was related to its high activity against SH-groups. With respect to therapeutic effects and hydrophilia the following order: II is greater than I is greater than III was observed. In our opinion the high hydrophilia of II is responsible for the significant and good inhibition of tumour growth.

Acrolein↗

[The rapid determination of urinary estriol in pregnancy by thin layer chromatography (author's transl)].

A simplified method for the determination of urinary estriol in pregnancy by thin layer chromatography is described. After precipitation of the conjugated substances with ammonium sulfate a short hydrolysis is carried out. Estriol is extracted with diethylether and coupled with dark blue R salt to an azo-dye. After thin layer chromatographic isolation, a spectrophotometric determination from the chromatogram is done. The recovery rate is 94%. The mean error in serial determination is +/- 5,4%. 1 nanogram (10(-9) g) of estriol can be determined from the thin layer chromatogram. The time required to obtain a result is just over 1 hour.

Chromatography, Thin Layer↗

[Specific determination of estriol-16-glucuronide from the urine of pregnant women in the last trimester].

A method for quantitative estimation of estriol-16-glucuronide in urine of pregnant women is given. The glucuronide is isolated by precipitation with ammoniumsulfate (70% w/v) followed by extraction with ether-ethanol (3:1). The estriol-16-glucuronide is converted with dark blue r to an azodye, which is separated from colored impurities by passing through a small column of sodium sulfate. The absorbance of the eluted dye is measured at 520 nm. 75 cases were analyzed and it was found that the estriol-16-glucuronide excretion increases in the 3rd trimester of pregnancy from the average value of 9.06 mg/24 hours in the 28th week to 22.11 mg/24 hours in the 42nd week of pregnancy.

Adult↗