[Analysis of peptides from animal and plant tissues]. / Analiz peptidov iz tkanei zhivotnykh i rastenii.

A new technique was developed for the analysis of peptide compositions of extracts from various animal and plant tissues. It involves the acidic extraction of a peptide fraction from the starting material and its precipitation with acetone, fractionation of peptides by ion-exchange chromatography by using a stepwise elution of fractions and detection by means of ninhydrin color reaction, and computer processing of the results. For the presentation of the results of analysis, chromatographic profiles and peptidograms were proposed. The results of analysis can be stored in a database and used for the creation of "generalized peptide portraits" and "differential peptide portraits" of the subjects investigated, which allow the identification of peptides characteristic of the subjects. The amount of peptide undergoing analysis ranged from 1 to 10 nmol.

[The toxicity of different forms of 24,25-dihydroxycholecalciferol preparations in rats]. / Issledovanie toksichnosti razlichnykh form preparatov 24,25-dioksikholekal'tsiferola u krys.

The purpose of the study was to examine the toxicity of 24,25-DOXK on calcium-phosphorus metabolic parameters. The rats from experimental groups received enteral 50- and 1,000-fold physiological doses of 24,25-DOXK (Vitamins Research Production Association) as a combination of R- and S-epimers and homogeneous R-epimer in sunflower oil solutions or ethanol mixture (1:4 propylene glycol) during 3 and 7 days. Though there was a stable tendency for hyperphosphatemia and altered blood calcium concentrations, the 24,25-DOHK formulations under test, unlike 1-OXK and 1,25-DOXK, displayed no toxic properties on the kidney, heart and aorta and produced a mineralizing effect on bone tissue in the acute period. Comparison of the properties shown by 24R,25-DOXK and 24R,S-DOXK showed that a combination of 24,25-DOXK R- and S-epimers was preferable for practical application.

[Assessment of the activity of choline acetyltransferase in heart tissues]. / Otsenka aktivnosti kholinatsetiltransferazy v tkaniakh serdtsa.

A procedure is described for the radioisotope assay of acetylcholine transferase activity (EC 2.3.1.6), which involved specific synthesis of acetylcholine in vivo. Bromine acetylcholine was used as an inhibitor of the enzyme; 14C-AcCoA was used as a substrate and product of the enzymatic reaction. 14C-acetylcholine was separated from the substrate by means of anion exchange chromatography. The procedure described was 5 times more sensitive than the methods developed by F. Fonnum (1975) and S. Tucek (1983) being similarly reproducible. The assay was tested in experiments with rats under various conditions of hyperbaric oxygenation, in simulation of myocardial infarction as well as in moderate immobilization stress. The findings suggest that estimation of the acetylcholine transferase activity may be involved in complex evaluation of the cholinergic system state in tissues, which is essential for the study of pathogenesis of their dysfunctions and development of respective approaches to eliminate these impairments.