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Now showing 1 - 10 of 17
  • Publication
    Bir Safra Asidi Olan TUDCA’nın Nöroprotektif Etkilerinin Deneysel Spinal Kord Travması Modelinde İncelenmesi
    (Türk Nöroşirurji Derneği, XIX. Bilimsel Kongresi, 2005) Kelten, B.; Kaya, M.; Antar, V.; Karaoğlan, A.; Akdemir, O.; Soy, O.; Çolak, A.; ÇELİK, ÖZGE; 113987
  • Publication
    Bir Genel Kaspaz İnhibitörü Olan QVD-OPH’nın Nöroprotektif Etkilerinin Deneysel Spinal Kord Travması Modelinde İncelenmesi
    (Türk Nöroşirurji Derneği, XIX. Bilimsel Kongresi, 2005) Antar, V.; Kelten, B.; Kaya, M.; Karaoğlan, A.; Akdemir, O.; Soy, O.; Sağmanlıgil, A.; Barut, Ş.; Çolak, A.; ÇELİK, ÖZGE; 113987
  • Publication
    Preparation of superoxide dismutase loaded chitosan microspheres: Characterization and release studies
    (Elsevier, 2007) Akbuğa, Fatma Jülide; ÇELİK, ÖZGE; 113987; 11241
    Superoxide dismutase (SOD) is the most potent antioxidant enzyme. In this study, SOD was encapsulated in chitosan microspheres to obtain suitable sustained protein delivery. Protein-loaded chitosan microspheres with various formulations were prepared based on complex coacervation process. Due to the inherent characteristic of SOD, high encapsulation efficiency could not be obtained with simple preparation method. The pH of chitosan solution is 3.0; when the chitosan microspheres were prepared with this solution, encapsulation was low. Therefore, several strategies have been tested to increase the encapsulation efficiency and good results have been obtained. 70–80% protein encapsulation efficiency was obtained. The addition of PEG to the protein solution enhanced the encapsulation efficiency also. Mean sizes of microspheres were between 1.38 and 1.94 μm. Factors affecting the release behaviour of SOD from microspheres have been studied. They included pH values of chitosan solution (the pH of chitosan solution is 3.0), addition of PEG to the protein solution and the use of adsorption technique. In general, biphasic release profiles were obtained with these formulations. The protein activity changed between 70 and 100% during the release. In general, the protein activity remained in acceptable limits. The SOD encapsulated chitosan microspheres can be prepared by changing the pH or addition of PEG, allowing the safe incorporation of protein for controlled release.
  • PublicationEmbargo
    Stimulation of Rapid Regeneration by a Magnetic Field in Paulownia Node Cultures
    (2008) Rzakulieva, Aitekin; ATAK, ÇİMEN; ÇELİK, ÖZGE; 113987; 6653
    In this study, the aim was to determine the effect of magnetic fields on regeneration of Paulownia node cultures. Paulownia tomentosa node cultures were used to generate explants and these explants were passed through a 2.9- 4.6-mT magnetic flux density 1 and 9 times at 2.2 and 19.8 seconds, respectively. Chlorophyll quantities, total RNA concentrations of shoots and shoot formation rates from control and treated explants were determined. While the shoot formation rate was 61.9% in the control group, this rate was increased in magnetic field experiments and shoot formation was 82.5% in the explants that were exposed to a magnetic field for a 2.2 second period. However, the regeneration percentage of the explants exposed to a MF for a period of 19.8 s was 45%. Chlorophyll a, chlorophyll b and total chlorophyll contents of the 2.2 s group were increased in comparison to the control group. Total RNA concentrations of seedlings regenerated from treatment explants treated for 2.2 seconds significantly increased in comparison to the control (p<0.05). Our experiments show that the exposure duration to MFs is an important factor for plant tissue. MFs may be used in in vitro regeneration studies rapid and for a short time.
  • Publication
    Calpain inhibitor AK 295 inhibits calpain-induced apoptosis and improves neurologic function after traumatic spinal cord injury in rats
    (Soc Espanola Neurocirugia, C/O Dr Poza, Gran Via Salzillo 42, 30005 Murcia, Spain, 2009-06) Çolak, Ahmet; Kaya, Mehmet; Karaoğlan, Alper; Sağmanlıgil, Ayhan; Akdemir, Osman; Şahan, Elife; ÇELİK, ÖZGE; TR113987; TR110929
    Background. An increase in the level of intracellular calcium activates the calcium-dependent neutral protease calpain, which in turn leads to cellular dysfunction and cell death after an insult to the central nervous system. fit this study, we evaluated the effect of a calpain inhibitor, AK 295, on spinal cord structure, neurologic function, and apoptosis after spinal cord injury (SCI) in a murine model. Methods. Thirty albino Wistar rats were divided into 3 groups of 10 each: the sham-operated control group (group 1), the spinal cord trauma group (group 2), and the spinal cord trauma plus AK 295 treatment group (group 3). After having received a combination of ketamine 60 mg/kg and xylazine 9 mg/kg to induce anesthesia, the rats in groups 2 and 3 were subjected to thoracic trauma by the weight drop technique (40 g-cm). One hour after having been subjected to that trauma, the rats in groups 2 and 3 were treated with an intraperitoneal injection of either dimethyl sulfoxide 2 mg/kg or AK 295 2 mg/kg. The effects of the injury and the efficacy of AK 295 were determined by an assessment of the TUNEL technique and the results of examination with a light microscope. The neurologic performance of 5 rats from group 2 and 5 from group 3 was assessed by means of the inclined plane technique and the modified Tarlov's motor grading scale 1, 3, and 5 days after spinal cord trauma. Findings. Light-microscopic examination of spinal cord specimens from group 2 revealed hemorrhage, edema, necrosis, and vascular thrombi 24 : hours after trauma. Similar (but less prominent) features were seen in specimens obtained from group 3 rats. Twenty-four hours after injury, the mean apoptotie cell numbers in groups I and 2 were zero and 4.57 +/- 0.37 cells, respectively. In group 3, the mean apoptotic cell number was 2.30 +/- 0.34 cells, a value significantly lower than that in group 2 (P < .05). Five days after trauma, the injured rats in group 2 demonstrated significant motor dysfunction (P < .05). In comparison, the motor scores exhibited by group 3 rats were markedly better (P < .05). Conclusions. AK 295 inhibited apoptosis via calpain-dependent pathway's and provided neuroprotection and improved neurologic function in a rat model of SCI. To our knowledge, this is the first study to evaluate the use of AK 295, a calpain inhibitor, after SCI. Our data suggest that AK 295 might be a novel therapeutic compound for the neuroprotection of tissue and the recovery of function in patients with a SCI.
  • Publication
    Bir Kalpain İnhibitörü Olan AK295’in Nöroprotektif Etkilerinin Deneysel Spinal Kord Travması Modelinde İncelenmesi
    (Türk Nöroşirurji Derneği, XIX. Bilimsel Kongresi, 2005) Kaya, M.; Antar, V.; Kelten, B.; Akdemir, O.; Karaoğlan, A.; Soy, O.; Çolak, A.; ÇELİK, ÖZGE; 113987
  • Publication
    Evaluation of Superoxide dismutase loaded microspheres
    (2007-01-11) Akbuğa, Fatma Jülide; ÇELİK, ÖZGE; 113987; 11241
  • Publication
    Gama Radyasyonun Soya (Glycine max (L.) Merrill) Yapraklarının Ultrastrüktürel ve Biyokimyasal Özellikleri Üzerine Etkisi
    (2009-06-22) Suludere, Zekiye; ATAK, ÇİMEN; ÇELİK, ÖZGE; 113987; 6653; 4019
  • Publication
    Development of Superoxide Dismutase Loaded Microspheres
    (2007-03-27) Akbuğa, Fatma Jülide; ÇELİK, ÖZGE; 113987; 11241
  • PublicationEmbargo
    The effect of magnetic field on the activity of superoxide dismutase
    (Haliç University, Faculty of Arts and Sciences, Department of Molecular Biology and Genetics, Fındıkzade 34280, İstanbul-Turkey, 2006) Büyükuslu, Nihal; ATAK, ÇİMEN; ÇELİK, ÖZGE; 6653; 113987; 109872
    The effects of magnetic field on superoxide dismutase activity were investigated. All living systems are affected by magnetic field and electromagnetic field in a way of their response systems. Since magnetic field has an impact on biochemical reactions that involve more than one unpaired electron, in our study SOD activity, one of the enzyme responsible for antioxidant system, was measured under magnetic fields using an apparatus explained at material methods. There has been a significant increase of SOD activity when passed 0, 1, 9 and 15 times at 2.9-4.6 mT magnetic field density for 0, 2.2, 19.8 and 33.0 seconds respectively.