Serap Erdem-Kuruca

IN VITRO EFFECTS OF VITAMIN C AND SELENIUM ON NK ACTIVITY OF PATIENTS WITH β -THALASSEMIA MAJOR

In this study, the in vitro effects of vitamin C and selenium on natural killer (NK) cell activity of β-thalassemia major patients was investigated. At first, significant decreased NK activity was found at E:T ratios of 1:1, 5:1, and 10:1 in whole thalassemia patients. Low-dose selenium treatment enhanced NK activity in patients but there was no change in the control group. High-dose selenium decreased NK activity significantly in splenectomized patients. Different doses vitamin C enhanced NK activity significantly in both splenectomized and unsplenectomized patients. According to these results, selenium dosage should be arranged carefully in thalassemia patients, whereas vitamin C can be used confidently.

Iron(III) and nickel(II) complexes as potential anticancer agents: synthesis, physicochemical and structural properties, cytotoxic activity and DNA interactions

Template reactions of 2-hydroxy-R-benzaldehyde-S-methylisothiosemicarbazones (R = 3-methoxy or 4-hydroxy) with the corresponding aldehydes in the presence of FeCl3 and NiCl2 yielded N1,N4-disalicylidene chelate complexes. The compounds were characterized by means of elemental and spectroscopic methods. The structure of complex 1 was determined by X-ray single crystal diffraction. Crystal data (Mo Kα; 296 K) are as follows: monoclinic space group P21/c, a = 12.9857(8) A, b = 7.8019(4) A, c = 19.1976(12) A, β = 101.655(5)°, Z = 4. Cytotoxic effects of the compounds were evaluated by the MTT assay in K562 leukemia, ECV304 endothelial and normal mononuclear cells, and DNA fragmentation analysis using the diphenylamine reaction was performed. The DNA binding capacity of thiosemicarbazones at IC50 and different concentrations was investigated. The DNA fragmentation percentage of compound treated cells was higher than that of non-treated control cells but was higher for compound 3 (84%) compared to the others. The interaction of compounds 1–4 and DNA was investigated voltammetrically by using nucleic acid modified electrodes after the double stranded fish sperm DNA (fsDNA), or poly(dA)·poly(dT), was immobilized onto the surface of pencil graphite electrodes (PGEs). Accordingly, the oxidation signals of DNA bases, guanine and adenine, were measured by using differential pulse voltammetry (DPV). The changes in the signals of guanine and adenine were evaluated before and after the interaction process. The results indicated that compound 3 was cytotoxic at very low concentrations in K562 leukemia cells unlike other cells and that could damage the DNA double stranded form, specifically the adenine base. Therefore, it may have a selective antileukemic effect and drug potential.

Fabrication of nanofiber mats from electrospinning of functionalized polymers

Electrospinning technique enabled us to prepare nanofibers from synthetic and natural polymers. In this study, it was aimed to fabricate electrospun poly(vinyl alcohol) (PVA) based nanofibers by reactive electrospinning process. To improve endurance of fiber toward to many solvents, PVA was functionalized with photo-crosslinkable groups before spinning. Afterward PVA was crosslinked by UV radiation during electrospinning process. The nanofiber mats were characterized by scanning electron microscopy (SEM). The results showed that homogenous, uniform and crosslinked PVA nanofibers in diameters of about 200 nm were obtained. Thermal stability of the nanofiber mat was investigated with thermal gravimetric analysis (TGA). Also the potential use of this nanofiber mats for tissue engineering was examined. Osteosarcoma (Saos) cells were cultured on the nanofiber mats.

The evaluation of human tenon's fibroblasts and endothelial cell responses to antifibrotics alone and in combination with α-tocopherol.

Abstract Purpose: We aimed to evaluate the influence of current antifibrotic agents as well as the possible results obtained by combining these agents. This study included α-tocopherol, a strong antifibrotic and an efficient neuromediator of pathways used by other agents. Materials and Methods: Mitochondrial Bcl-2, Bax, cytochrome c and cytoplasmic caspase-3 expression, as well as toxic effect patterns, mitosis and cellular reactions due to α-tocopherol alone or combined with paclitaxel, mitomycin C and 5-flurouracil (5-FU), was studied in series obtained from human endothelial and primary Tenon’s fibroblast cell cultures. Results: The strongest apoptotic effect in both cell groups belonged to paclitaxel, followed by mitomycin C, and despite the overall suppressive effect of the α-tocopherol combination, mitomycin C increased its efficiency on the endothelial cells. The apoptosis/necrosis ratio was highest in α-tocopherol and lowest in paclitaxel, with α-tocopherol generally decreasing necrosis. Bax was observed at a high level with mitomycin C. Cytotoxicity was the highest with paclitaxel, and the caspase-3 reaction was markedly higher with mitomycin C in both cell types. In the α-tocopherol and 5-FU slides, mitosis and a layered formation were observed. The addition of α-tocopherol reduced the cytotoxicity of all antifibrotic agents in both cell series by decreasing the cell numbers, leading to necrosis. Conclusions: Alone or in combination, the use of α-tocopherol and 5-FU is safer than other agents. By suppressing the cytotoxic effects of other antifibrotic agents, α-tocopherol is a promising drug for improving the effects of antifibrotics in many aspects of medicine. In addition, it has the potential to play a role beyond its antioxidant and antifibrotic activity in ocular surgery.

Effects of micro environmental factors on natural killer activity (NK) of beta thalassemia major patients.

The physiological mechanisms of decreased NK activity of β-Thalassemia major (BTM) patients are unknown. To assess in vitro effects of mononuclear cells and their cytokine secretion on NK activity, we compared activator receptor levels and cytotoxic activity of purified NK cells and NK cells in mononuclear cells (MNC) pools. We collected cell supernatant from unincubated and incubated MNC with K562 cells and measured their secreted cytokines levels. CD16 was lower on the surface of NK cells in MNC pools from BTM patients compared to healthy volunteers. This inhibition does not appear when NK cells were purified. NKp30 levels in NK cells decreased both as purified cells and as part of a pool of MNC in BTM patients. After incubation of MNC pools with K562 target cells, we found that supernatant levels of IL10, TGFβ1 and IL15 cytokines were also significantly higher in BTM patients compared to healthy volunteers.

Novel electrospun polycaprolactone/graphene oxide/Fe3O4 nanocomposites for biomedical applications

In this study, one of the most promising methods of tailoring a composite scaffold material in nano sized diameters, electrospinning method were used to produce Polycaprolactone (PCL)/Graphene Oxide (GO)/Iron(II, III) Oxide (Fe3O4) nanocomposite fibers as biocompatible scaffolds for biomedical applications. Products were analyzed by scanning electron microscopy (SEM) for morphological analysis of the electrospun nanocomposites and Fourier Transform Infrared Spectroscopy (FTIR) was used to determine functional groups of the PCL, GO, and Fe3O4 materials in the electrospun nanocomposites. For physical properties, viscosity, density, permittivity, dielectric loss and liquid and solid state alternating current conductivity, measurements were done for each nanocomposite fibers. Effects of concentration percentage of GO on permittivity, dielectric loss and AC conductivity have been analyzed by using measured and calculated data. Trend lines have been drawn for permittivity, dielectric loss and conductivity via concentration percentage of GO. The relation between ac conductivity and frequency have been studied for each concentration percentage of GO and interpretations have been done by using the obtained results.

IN VITRO EFFECTS OF GROWTH FACTORS AND INTERFERON-α ON BUSULFAN CYTOTOXICITY

An experimental approach to increasing the effectiveness of leukemia treatment with S-phase-specific cytotoxics is to increase the cycling of leukemia cells with growth factors. However, growth factors may have a different relationship with non-cell-cycle-specific agents. The authors examined the effects of granulocyte colony-stimulating factor (G-CSF), granulocyte/macrophage colony-stimulating factor (GM-CSF), and interferon-α (INF-α) on the cytotoxic effects of the alkylating agent busulfan on the erythro-myeloid cell line K562. G-CSF and GM-CSF increased the proliferation and colony-forming ability of K562 cells and protected the cells from busulfan effects. INF-α decreased the colony-forming ability and proliferation of the K562 cells and demonstrated a possibly additive effect with busulfan. In the cell line K562, the growth factors G-CSF and GM-CSF protected the cells from the non-cell-cycle-specific alkylating agent busulfan, whereas IFN-α demonstrated an additive cytotoxic effect.