Identification of products formed during UV irradiation of tamoxifen and their use for fluorescence detection in high-performance liquid chromatography.

During the UV irradiation of tamoxifen, isomerization of the trans to the cis isomer takes place and consequently corresponding highly fluorescent phenanthrene derivatives are formed. Their formation can be used for the sensitive and selective detection of tamoxifen in high-performance liquid chromatography (HPLC). The structure of photoproducts was identified by 1H NMR spectroscopy, HPLC, gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. Owing to the variety of products formed and the higher selectivity and fluorescence response, on-line postcolumn photocyclization is preferred to the precolumn mode. A chromatographic system for the separation of isomers and photoproducts is suggested.

Evaluation of protein mixtures in adults on the basis of scoring pattern deduced from Kofrányi's results.

Minimum protein requirements for adult males found by Kofrányi in testing protein mixtures were compared with amino acid scoring pattern in which total non-essential amino acids were also included. For protein mixtures composed of different ratios of animal and plant proteins the least minimum of protein required corresponded to the maximum of the courses of chemical score when non-essential amino acids, lysine, sulfur amino acids or tryptophan respectively were taken as limiting. Particular comparisons indicate that total non-essential amino acids ought to be included in amino acid scoring pattern.

[The effect of adding Rumensin to the diet of bulls on the quality of their meat]. / Vliv pridavku Rumensinu v diete býcku na kvalitu jejich masa.

In a pilot experiment, bullocks were given diet with a sodium monensinate supplement as the Rumensin preparation. The dose of the supplement was 125 mg per head/day and the medicated feed was given to the bullocks for 14 months. The daily weight gain of the tested bullocks increased by 3.85% and feed consumption decreased by 7.12%. The meat of the ten bullocks examined (m. longissimus dorsi) showed no statistically significant changes in the basic chemical composition as compared with the meat of ten control bullocks. In the tested group the content of hydroxyproline in meat decreased by 35.14% (from 0.12 to 0.08 g per 100 g of fresh tissue - p less than 0.05). The content of glycine decreased by 8.82% (from 3.63 to 3.31 g per 100 g of dry matter - P less than 0.01). The content of alanine decreased by 5.86% (from 5.12 to 4.82 g per 100 g of dry matter - P less than 0.05). As to essential amino acids, the content of valine in the meat of the tested bullocks increased by 4.76% (from 3.99 to 4.18 g per 100 g of dry matter - P less than 0.05). Sodium monensinate exerted a favourable influence on weight gains and nutrient conversion in the bullocks. It had no effect on the basic chemical composition and no marked influence on the content of amino acids, except hydroxyproline and, particularly, essential amino acids in the meat of the tested bullocks. A reduction in the content of hydroxyproline signalizes higher-value proteins.