Simultaneous analysis of four sulfonamides in chicken muscle tissue by HPLC.

The aim of this study was to develop a simple high-performance liquid chromatography (HPLC) with UV detection method for the determination of four sulfonamides in chicken muscle tissue. The sulfonamides were extracted with acetonitrile, acetone and dichloromethane. Separation was carried out on a C18 column using as the mobile phase a mixture of 6‰ disodium hydrogen phosphate and methanol.

Total and free amino acids in the "Crinofizin" pineal extract.

In order to establish the chemical nature of Crinofizin, a protidic extract obtained from bovine pineal, the amino acids content was analysed using two analytic programs: one for biologic fluids, the other for protein hydrolysates. The results showed that the pineal extract contains besides the common protein amino acids reported earlier, others, rare in proteins, such as hydroxyproline, hydroxylysine and 1-methylhistidine as well as non-protein amino acids. From among the latter, the alpha-aminoadipic acid, beta- alanine, O-cysteine, are found only in a bound form, and are detected only by hydrolysis.

Purification and physico-chemical characterization of the antigonadotropic fractions obtained by ultrafiltration from the pineal extract.

In order to isolate the antigonadotropic factor from a pineal extract prepared from bovine pineals the authors first applied ultrafiltration, which yielded three fractions: F1 greater than 10 kDa, 1 kDa less than less than F2 less than 10 kDa, and F3 less than 1 kDa. Examination of the biologic activity showed that only F1 and F2 have a statistically significant antigonadotropic activity. Ion exchange chromatography of F1 yielded two subfractions: one, F11, which was not retained, and another one, F12, which was retained by the exchanger.

The antigonadotropic activity and amino acid composition of a total and dialyzed melatonin-free pineal extract.

The antigonadotropic activity of a melatonin-free pineal extract before and after a 24 h dialysis was assessed by the mouse uterine-weight test. In both cases, the uterus-stimulating effect of HCG was inhibited, showing that after dialysis the extract not only retains its effect but that the latter is even higher. The amino acids content established by an amino acid analyzer was the same in two batches of extract obtained from two different stores of pineal powder.