Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 28

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  colchicine
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
A novel scheme for modeling 3D QSAR has been developed. A method involving multiple self-organizing neural network adjusted to be analyzed by the PLS (partial least squares) analysis was used to model 3D QSAR of the selected colchicinoids. The model obtained allows the identification of some structural determinants of the biological activity of compounds.
Seeds of sesame (Sesamum indicum L), genotypeTMV3 were treated with various concentrations of EMS and Colchicine like 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8 and 2.0 % and the LD50 values observed at 1.0 % of EMS and 0.6 % of Colchicine. Based on their LD50 values appreciable concentrations only selected for further study and their effects on various morphological characters such as plant height per plant, number of branches per plant, number of leaves per plant, days to first flowering, number of capsules per plant, number of seeds per capsule and seed yield per plant (g) were measured quantitatively and the results showed that all the characters were consequently or significantly reduced when compared to control and also EMS showed more effective than colchicine.
Thyrotropin-releasing hormone (TRH) is engaged in the modulation of the hypothalamo-neurohypophysial system activity. Effects of repeated intravenously injections of TRH in a dose of 100 ng/100 g b.w. on vasopressin (VP) and oxytocin (OT) biosynthesis and release from the hypothalamo-neurohypophysial system was investigated in rats in different age (1-, 3- or 7-months of the life). To estimate the biosynthesis rate of both neurohormones the colchicine procedure was used (the dose of 5 µg/5 µl icv 20 hours before the decapitation). It has been observed that vasopressin synthesis in the hypothalamus increased gradually with maturation of rats, while OT biosynthesis decreased in the same animals. Hypothalamic biosynthesis rate of VP and OT is most effective in youngest rats and declines during the adolescence of animals. Thyrotropin-releasing hormone directly affects VP-ergic and OT-ergic hypothalamic neurons activity and both neurohormones biosynthesis process. This effect, however, is opposed: TRH acts as a stimulator of vasopressin biosynthesis most of all in young male rats and as an inhibitor for oxytocin biosynthesis especially in mature animals.
Besides its use in gouty arthritis, colchicine has been found to be useful for anticancer treatment. However, the severe toxicity and low therapeutic index of colchicine limit its therapeutic use. It was hypothesized that toxicity of colchicine can be reduced if it is encapsulated in liposomes. The objective of this study was to determine and compare in vitro cellular uptake and cytotoxicity of colchicine with that of liposome encapsulated colchicine. Colchicine was encapsulated in negatively charged unilamellar liposomes (LUVs). Two cell lines, human macrophages (U-937) and murine myeloma (B-type, P3X63.Ag8.653) cells were used for these investigations. Cells were incubated with colchicine or liposomal colchicine and cellular uptake was determined by means of radioactive labeled colchicine. Cytotoxicity was determined by MTT (3-[4,5-dimethylthiazol- 2-yl]-2,5-diphenyltetrazolium bromide) assay. Human macrophages as well as murine myeloma cells showed greater uptake of liposomal colchicine than plain colchicine. However, cytotoxicity of liposomal colchicine to human macrophages was less compared to that of plain colchicine. On the other hand, in the case of murine myeloma cells, cellular uptake as well as cytotoxicity was greater with liposomal colchicine than that with plain colchicine. These results indicate that liposomal encapsulation of colchicine could avoid or reduce its toxicity and improve therapeutic efficacy.
The genome doubling agent colchicine was used effectively to obtain tetraploid plants in dragonhead. Treatment of apical meristem of seedlings was carried out in two stages. The first stage was when the cotyledon leaves emerged. The second stage was when the two true leaves emerged. Six levels of colchicine concentrations: 0, 0.05, 0.1, 0.2, 0.5, and 0.75% were applied in each of these stages. Seedling treatment in the stage of emergence of two true leaves with 0.1% colchicine solution proved to be the most effective in producing autotetraploids. Morphological, cytological and flow cytometry analyses showed the increase of chromosome numbers from 2n=2x=10 to 2n=4x=20. The increase of ploidy levels caused major changes in some morphological and physiological traits and active substances in dragonhead.
Studies on the possible interference of colchicine and H2O2 with the activity of some antioxidant enzymes were carried out on Arabidopsis thaliana v. Columbia grown in Murashige and Skooge nutrient medium. Measurements of superoxide dismutase (SOD), guaiacol peroxidase (POX), ascorbate peroxidase (APX) and catalase (CAT) activities were conducted spectrophotometrically. In the presence of colchicine, SOD activity increased, while CAT, APX and POX activities decreased. Inhibitory H2O2 effects on the activity of the enzymes were found. Colchicine pre-treatment resulted in an increase in CAT activity and a further increase in SOD activity in plants treated with H2O2.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.