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Biomedical subjects

O Ianăş

Publications and source records attributed to O Ianăş.

At least 19 recordsLinked to original sources
PubMed1992

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. Other amino acids, such as taurine, glutamine, citruline are present only in free form whereas the alpha-amino-n-butyric acid, GABA, ethanolamine and ornithine are present in both forms, free or bound. The paper discusses the physiologic significance of some amino acids.

Amino Acids↗
PubMed1991

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. Both subfractions showed biologic activity. While F11 is closer to F2 less than 10 kDa, F12 has a molecular weight around 13.7 kDa, as resulted after applying the SDS-PAGE procedure. The F1 fraction has a proteic content of 903 micrograms/ml, F11 = 308 micrograms/ml and F12 = 247 micrograms/ml. Amino acids assay showed that the F12 subfraction has the same composition as F1 and the F11 subfraction also has free amino acids which indicates a process of adsorption of small molecules on large molecules. The F2 less than 10 kDa fraction, biologically active, has a proteic content of 433 micrograms/ml and an amino acids composition similar to F11 except for cysteine and methionine. The F3 less than 1 kDa fraction with a proteic content of 79 micrograms/ml having an amino acid composition in which prevails the glutamic acid shows poor antigonadotropic activity. The results of this study, as well as the fact that the antigonadotropic activity is concentrated in fractions both above and under 10 kDa, suggests at least two hypotheses: either that the pineal antigonadotropic factor exists under various molecular forms in which the activity is preserved, or that the antigonadotropic factor is a peptide with strong aggregation properties as demonstrated in our study.

Amino Acids↗
PubMed1991

Melatonin involvement in oxidative processes.

The fact that the pineal gland, by its melatonin (MT) production, responds to environmental light variations (the day-night cycle), being also a modulator of the body adaptation to these conditions, may lead to the assumption of its involvement in the body oxidative processes. The redox capacity of melatonin was followed-up in vitro by the chemiluminescence phenomenon. The system generating chemiluminescence as well as free radicals was made up of luminol and H2O2. Incubation of melatonin in doses of 0.08-0.5 microM/ml with the generating system showed that in doses under 0.25 microM/ml melatonin has a pro-oxidative effect while in doses above this value it has an antioxidative effect. The diagram of the results shows the answer specific to a modulator. The study of the correlation between the dose of melatonin with highest pro-oxidative properties and the various peroxide concentrations in the generating system showed that melatonin gets antioxidative properties with the increase in peroxide concentrations (less than 8 mM/ml). In the presence of a hypothalamic homogenate, which is a stimulant of the chemiluminescence-generating system (PXI = 16), melatonin has a dose-dependent antioxidative effect. Similar results were also obtained by adding tryptophan--a free radicals acceptor (PXI = 0.1) and the substrate in melatonin synthesis to the reaction medium. Melatonin in low concentrations (greater than 0.1 microM/ml) has an antioxidative effect while in higher doses it has a dose-dependent pro-oxidative effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1978

Anti-LH and FSH activity of melatonin-free pineal extract.

The influence of melatonin (MEL)-free pineal extract on luteinizing hormone (LH) and follicle stimulating hormone (FSH) was studied comparatively with that of MEL. Administration of pineal extract to rats, 3 days running, was found to induce a statistically significant decrease of serum LH and FSH. This effect was also demonstrated by the biological tests used, namely, a decrease in weight of both rat ventral prostate (anti-LH activity) and mouse uterus (anti-FSH activity). MEL administered for 3 days, in doses of 1 microgram/day in the ventral prostate weight test or of 10 microgram in the uterine weight test, failed to induce comparable effects. The identity of the pineal substances responsible for the anti-gonadotropic activity of the pineal gland is discussed.

Animals↗