Yazar "Ülger, H." seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Analysis of the Embryonic Growth Supporting Fractions of Extra Embryonic Coelomic Fluid (EECF)
    (1997) Karabulut, A. K.; Layfield, R.; Ülger, H.; Pratten, M. K.
    [Abstract not Available]
  • Küçük Resim
    Öğe
    Protection by Free Oxygen Radical Scavenging Enzymes Against Salicylate-İnduced Embryonic Malformations in Vitro
    (Pergamon-Elsevier Science Ltd, 2000) Karabulut, A. K.; Ülger, H.; Pratten, M. K.
    Salicylates are among the oldest and most widely used drugs and are known to lead to foetal death, growth retardation and congenital abnormalities in experimental animals. In this study, the effects of acetyl salicylic acid (ASA), salicylic acid (SAL) and sodium salicylate (NaSAL) on early organogenesis and the interaction of these molecules with free radicals has been investigated. Postimplantation rat embryos were cultured in vitro from day 9.5 of gestation for 48 hr. ASA, SAL and NaSAL were added to whole rat serum at concentrations between 0.1 and 0.6 mg/ml. Also, the lowest effective concentration of ASA for all parameters (0.3 mg/ml) and the same concentration of NaSAL and SAL was added to the culture media in the presence of superoxide dismutase (SOD) (30 U/ml) or glutathione (0.5 mu mol/ml). The growth and development of embryos was compared and each embryo was evaluated for the presence of any malformations. When compared to growth of control embryos, the salicylates decreased all growth and developmental parameters in a concentration-responsive manner. There was also a concentration-related increase in overall dysmorphology, including the incidence of haematoma in the yolk sac and neural system, open neural tube, abnormal tail torsion and the absence of fore limb bud. When SOD was added in the presence of ASA, growth and developmental parameters were improved and there was a significant decrease in the incidence of malformations. Addition of SOD also decreased the incidence of malformations in the presence of SAL, but did not effect the growth and developmental parameters of SAL and NaSAL. There was no significant difference between the embryos grown in the presence of these three molecules on the addition of glutathione. The effects of salicylates might involve free oxygen radicals by the non-enzymatic production of the highly teratogenic metabolites 2,3- and 2,5-dihydroxybenzoic acid. An enhanced production of these metabolites in embryonic tissues may be directly related to the increased risk of congenital malformations.
  • Küçük Resim
    Öğe
    Teratogenicity of Edoferon Kappa A, a Molecule Derived From Salicylate, in Cultured Rat Embryos: Differences From Salicylate and Interaction With Free Oxygen Radical Scavenging Enzymes
    (Wıley, 2000) Karabulut, A. K.; Ülger, H.; Pratten, M.
    The effect of edoferon kappa A (E-KA), a non-specific immunomodulatory and anti-neoplastic chemical substance derived from the methyl form of salicylate (acetyl salicylic acid; ASA), on mammalian embryos was studied and compared to the effects of ASA. Rat embryos were cultured in vitro from 9.5 days of gestation for 48 h. E-KA (0.1-12.8 mg/ml) and ASA (0.1-0.6 mg/ml) were added to the whole rat serum. To investigate the interaction of these molecules with antioxidant agents, the lowest effective concentrations of E-KA (0.6 mg/ml) and ASA (0.3 mg/ml) for all parameters were added to the culture media in the presence of superoxide dismutase (SOD) (30 U/ ml) or glutathione (0.5 mu mol/ml). The growth and development of embryos was compared and each embryo was evaluated for the presence of any malformations. E-KA and ASA decreased growth and development in a concentration-responsive manner. There was also a concentration-related increase in overall dysmorphology (haematoma in the yolk sac and neural system, open neural tube, abnormal tail torsion and the absence of fore limb bud). There were no statistically significant differences between the control and embryos grown in the presence of 0.1-0.4 mg/ml E-KA, although the effects of ASA started at a concentration of 0.2 mg/ml. Embryos showed significant growth retardation in all scoring criteria and severe malformations when 0.5-3.2 mg/ml E-KA and 0.3-0.6 mg/ml ASA were added. When SOD was added, there was a significant decrease in the incidence of malformations and growth and developmental parameters were increased but this decrease never reached the control level. We concluded that E-KA has direct toxic effects on the developing embryo but at much higher concentrations than ASA, and the teratogenic effects of these molecules might be related to free oxygen radicals.