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[en] Radioenzymatic assays are widely used for the quantification of a number of biogenic amines. All previous procedures have utilized methyltransferases derived from mammalian tissues. In this assay for the quantification of the trace aralkylamines, p-tyramine (p-tym) and phenylethylamine (PEA), an enzyme, tyramine N-methyltransferase isolated from sprouted barley roots was used. The enzyme was specific for phenylethylamines. Of 26 structurally-related compounds, only p-tym, PEA, m-tym and amphetamine were substrates in vitro. Theoretic maximal methylation of substrates occurred at 10-20⁰C. When TLC was used to separate the radiolabeled reaction products, a specific method was developed for p-tym and PEA. The assay had a sensitivity of 0.8 and 2.8 pg/tube with a C.V. < 5% and was applicable to human plasma and urine. Assay throughput is similar to that of other TLC based radioenzymatic assays

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[en] Various species of rodents are distinguished by their radiosensitivity (increasing): bank vole < Wistar rat < wild mouse < CC₅₇Br mouse < golden hamster < BALB mouse < guinea pig. There is a positive correlation between radiosensitivity of these species and catecholamines content in the adrenals, urea and blood; and negative correlation between radiosensitivity and adrenaline and noradrenaline concentrations in liver and spleen cells. Presumable causes of this correlation, and the possibility of application of the index under study for predicting the organism radiosensitivity and forecasting the outcome of radiation damage are discussed

[en] β-CD and CM-β-CD as chiral NMR shift agents were used to resolve the enantiomers of noradrenaline (NA). The stoichiometry of each complex formed between the CDs and the enantiomers of NA was found to be 1 : 1 through the continuous variation plots. The binding constants (K) of the complexes were determined from 1H NMR titration curves. This result indicated that both β-CD and CM-β-CD formed the complexes with the S (+)-NA more preferentially than its R(.)-enantiomer. The K values for the complexes with β-CD (KS(+) = 537 M^-1 and K_R(_-) = 516 M^-1) was larger than those with CM-β-CD (K_S(₊) = 435 M^-1 and K_R(_-) = 313 M^-1), however, enantioselectivity (α) of S(₊)- and R(-)-NA to CM-β-CD (α = 1.38) was larger than that to β-CD (α = 1.04), indicating that CM-β-CD was the better chiral NMR solvating agents for the recognition of the enantiomers of NA. Two dimensional rotating frame nuclear Overhauser enhancement spectroscopy (ROESY) experiments were also performed to explain the binding properties in terms of spatial fitting of the NA molecule into the macrocyclic cavities

[en] A spectro fluorometric method was developed for determination of brassinosteroids plant hormones based on the reaction between brassinolide and m-dansylaminophenylboronic acid. 90 μM of m-dansylaminophenylboronic acid solution was chosen as the optimal concentration of the reagent. The temperature of the reaction was 30 degree Celsius (room temperature) for 20 min duration in 5 mM phosphate buffer solution, pH 7. The excitation and emission wavelengths were 380 nm and 505 nm, respectively. Under optimal condition, linearity was found in the range 1-50 μM. Standard addition was used for the brassinosteroids determination in bio-extract samples, without any sample preparation. Limit of detection (3SD, n=10) of 0.24 μM and limit of quantitation (10SD, n=10) of 0.48 μM were obtained using sample blank with this standard addition method. Result was demonstrated to be a suitable semi-quantitative technique and was applied successfully for the determination of total brassinosteroids plant hormones equivalent to brassinolide. (author)

[en] After intra-aortic administration of ³H-angiotensin II in the rat, the radioactivity rapidly concentrates within the kidney. It was of interest to see where in the kidney this radioactivity was localized. The autographic experiments have shown that there exists a specific interaction between angiotensin II and the glomerular mesangial cells, but the presence of true biological receptors for the hormone in these mesangial cells was not demonstrated