Browsing by Subject "Proton Magnetic Resonance Spectroscopy"

Filter results by typing the first few letters
Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    A bifunctional photosensitizer for enhanced fractional photodynamic therapy: singlet oxygen generation in the presence and absence of light
    (Wiley-VCH Verlag, 2016) Turan, I. S.; Yildiz, D.; Turksoy, A.; Gunaydin, G.; Akkaya, E. U.
    The photosensitized generation of singlet oxygen within tumor tissues during photodynamic therapy (PDT) is self-limiting, as the already low oxygen concentrations within tumors is further diminished during the process. In certain applications, to minimize photoinduced hypoxia the light is introduced intermittently (fractional PDT) to allow time for the replenishment of cellular oxygen. This condition extends the time required for effective therapy. Herein, we demonstrated that a photosensitizer with an additional 2-pyridone module for trapping singlet oxygen would be useful in fractional PDT. Thus, in the light cycle, the endoperoxide of 2-pyridone is generated along with singlet oxygen. In the dark cycle, the endoperoxide undergoes thermal cycloreversion to produce singlet oxygen, regenerating the 2-pyridone module. As a result, the photodynamic process can continue in the dark as well as in the light cycles. Cell-culture studies validated this working principle in vitro.
  • Thumbnail Image
    ItemOpen Access
    Perisylvian GABA levels in schizophrenia and bipolar disorder
    (Elsevier Ireland Ltd, 2017) Atagün, M. İ.; Şıkoglu, M. E.; Soykan, Ç.; Can, S. S.; Ulusoy-Kaymak S.; Çayköylü, A.; Algın O.; Phillips, M. L.; Öngür, D.; Moore, C. M.
    The aim of this study is to measure GABA levels of perisylvian cortices in schizophrenia and bipolar disorder patients, using proton magnetic resonance spectroscopy (1H-MRS). Patients with schizophrenia (n = 25), bipolar I disorder (BD-I; n = 28) and bipolar II disorder (BD-II; n = 20) were compared with healthy controls (n = 30).1H-MRS data was acquired using a Siemens 3 T whole body scanner to quantify right and left perisylvian structures’ (including superior temporal lobes) GABA levels. Right perisylvian GABA values differed significantly between groups [χ2= 9.62, df: 3, p = 0.022]. GABA levels were significantly higher in the schizophrenia group compared with the healthy control group (p = 0.002). Furthermore, Chlorpromazine equivalent doses of antipsychotics correlated with right hemisphere GABA levels (r2= 0.68, p = 0.006, n = 33). GABA levels are elevated in the right hemisphere in patients with schizophrenia in comparison to bipolar disorder and healthy controls. The balance between excitatory and inhibitory controls over the cortical circuits may have direct relationship with GABAergic functions in auditory cortices. In addition, GABA levels may be altered by brain regions of interest, psychotropic medications, and clinical stage in schizophrenia and bipolar disorder. � 2016 Elsevier Ireland Ltd
  • Thumbnail Image
    ItemOpen Access
    Release and antibacterial activity of allyl isothiocyanate/β-cyclodextrin complex encapsulated in electrospun nanofibers
    (Elsevier, 2014) Aytac Z.; Dogan, S.Y.; Tekinay, T.; Uyar, Tamer
    Allyl isothiocyanate (AITC) is known as an efficient antibacterial agent but it has a very high volatility. Herein, AITC and AITC/β-cyclodextrin (CD)-inclusion complex (IC) incorporated in polyvinyl alcohol (PVA) nanofibers were produced via electrospinning. SEM images elucidated that incorporation of AITC and AITC/β-CD-IC into polymer matrix did not affect the bead-free fiber morphology of PVA nanofibers. 1H-NMR and headspace GC-MS analyses revealed that very low amount of AITC was remained in PVA/AITC-NF because of the rapid evaporation of AITC during the electrospinning process. Nevertheless, much higher amount of AITC was preserved in the PVA/AITC/β-CD-IC-NF due to the CD inclusion complexation. The sustained release of AITC from nanofibers was evaluated at 30°C, 50°C and 75°C via headspace GC-MS. When compared to PVA/AITC-NF, PVA/AITC/β-CD-IC-NF has shown higher antibacterial activity against Escherichia coli and Staphylococcus aureus due to the presence of higher amount of AITC in this sample which was preserved by CD-IC. © 2014 Elsevier B.V.