Yazar "Demir, Halit" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • [ X ]
    Öğe
    CHANGE OF ANTIOXIDANT ENZYME ACTIVITIES, SOME METALS AND LIPID PEROXIDATION IN ALZHEIMER'S DISEASE
    (Carbone Editore, 2016) Arslan, Ayse; Tuzun, Fatma Aykan; Tamer, Sibel; Demir, Halit; Aycan, Abdurrahman; Demir, Canan; Tasin, Muhterem
    Introduction: Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive cognitive regression and memory loss. It has been claimed that oxidative stress and factors such as metal accumulation in the brain play important roles in the etiopathogenesis of the disease. Material and methods: The subjects of this study consisted of 24 individuals with Alzheimer's disease and 15 healthy agematched controls. Blood samples were withdrawn from the patients and healthy controls, and the activities of antioxidant enzymes SOD (Superoxide Dismutase), GSH (Glutathion), GSHPx (Glutathion peroxidase), GST (Glutathion S-Transferase) and MDA (Malondialdehyde) levels were determined by Spectrometer. Some metals and heavy metals were measured by atomic absorption spectrometry (AAS). Results: Biochemical analyses showed a significant decrease of the main enzymatic antioxidant defences (SOD, GSH, GST and GSHPx) and increased production of lipid peroxidation marker (MDA) in the serum of AD patients, compared to age-matched control group (p< 0.001). Also the levels of Zn, Mg, and Mn was lower and Fe, Pb, and Cd was higher in the patient group, compared to the control group. Serum Cu and Co levels did not differ significantly between the patient and control groups (p> 0.001). Conclusion: These results supports the theory that in AD there is a defect in the antioxidant defense system, which may lead to oxidative damage. Also alterations in some trace metals and their related enzymes may play a role of etiopathogenesis in AD.
  • [ X ]
    Öğe
    In vitro DNA damage, protein oxidation protective activity and antioxidant potentials of almond fruit (Amygdalus trichamygdalus) parts (hull and drupe) using soxhlet ethanol extraction
    (Springer, 2020) Meydan, Ismet; Kizil, Goksel; Demir, Halit; Ceken Toptanci, Bircan; Kizil, Murat
    Almond is a nut that is consumed abundantly all over the world. In Turkey, almonds are grown in most parts of the Turkey and the consumption of nuts has become an essential part of healthy life. Almond contain powerful nutrients, which may be related to their fatty acid composition. Therefore, the aim of present study was to investigate the antioxidant potentials and the protective activity of ethanol extraction ofAmygdalus trichamygdalusfruit parts (Hull and Drupe) against the lipid peroxidation, oxidative DNA damage and protein oxidation using soxhlet ethanol extraction. To the best of our knowledge, our study can be evaluated as the first report. The total phenolic content was found to be equivalent to 28.16 +/- 9.990 mu g/g gallic acid extract and the total flavonoid content was equivalent to 8.866 +/- 0.208 mu g/g quercetin extract. The present study shows thatA. trichamygdalusextract have good protective activity against lipid peroxidation in the FeCl2-H(2)O(2)system. The extract also showed a strong DPPH radical scavenging ability in a concentration-dependent manner. At 2000 mu g/ml, the DPPH radical scavenging activity was found to be 84.47 +/- 0.147%. The protein oxidation was also inhibited byA. trichamygdalusextract. At 2000 mu g/ml,A. trichamygdalusextract protected protein oxidation by 76.27 +/- 1.14%. In addition, the DNA oxidation damage against OH radicals resulting from H(2)O(2)photolysis was inhibited concentration dependently and DNA damage was suppressed by 50.26 +/- 2.6% at 1000 mu g/ml concentration. The results suggest thatA. trichamygdalusfruit extract have antioxidant activity and protect lipid, protein and DNA against oxidative damage. Therefore, the extract may be useful in the food industry as natural antioxidants.
  • [ X ]
    Öğe
    Protective Ability of Ethanol Extracts of Hypericum Scabrum L. and Hypericum Retusum Aucher Against the Protein Oxidation and DNA Damage
    (Taylor & Francis Inc, 2011) Kizil, Goksel; Kizil, Murat; Ceken, Bircan; Yavuz, Murat; Demir, Halit
    Inhibition of protein oxidation and DNA damage by reactive oxygen species (ROS) would confer benefit to living organisms exposed to oxidative stress, because oxidized proteins are associated with many diseases and can propagate ROS-induced damage. In this study, the ability of the ethanol extracts of Hypericum retusum Aucher (HR) and Hypericum scabrum L (HSm) to protect bovine serum albumin (BSA) from oxidation and DNA damage by hydroxyl radical derived from the Fenton system (Fe3+/H2O2/ascorbic acid) were measured. The ethanol extracts of HR and HSm at different concentrations (50-1000 g/mL) efficiently prevented protein oxidation induced by hydroxyl radicals as assayed by protein oxidation markers, including protein carbonyl formation (PCO) and polyacrylamide gel electrophoresis. The effect of ethanol extracts of HR and HSm on DNA cleavage induced by UV-photholysis of H2O2 using pBluescript M13+ plasmid DNA were also investigated. These extracts significantly inhibited DNA damage induced by ROS. Therefore, Hypericum retusum, and Hypericum scabrum extracts may be useful in the food industry as effective synthetic antioxidants.
  • [ X ]
    Öğe
    The relationship between serum paraoxonase levels and carotid atherosclerotic plaque formation in Alzheimer's patients
    (Termedia Publishing House Ltd, 2016) Arslan, Ayse; Tuzun, Fatma Aykan; Arslan, Harun; Demir, Halit; Tamer, Sibel; Demir, Canan; Tasin, Muhterem
    Low paraoxonase 1 (PON1) activity and carotid atherosclerosis have been suggested to be important risk factors for dementia. However, the studies to date could not fully clarify the relationship between PON1, carotid atherosclerosis and dementia. The present study aimed to measure carotid atherosclerosis and PON1 activity in Alzheimer's Disease and to evaluate the relationship between them. The study included 25 Alzheimer's patients and 25 control subjects, for a total of 50 individuals. The study measured the serum PON1 activity and other biochemical parameters and carotid atherosclerotic plaque values of the participants. The mean paraoxonase activity (31.06 +/- 2.31 U/L) was significantly lower in the Alzheimer's group compared to the control group (59.05 +/- 7.05 U/L) (P < 0.001). Nonetheless, the carotid plaque values were significantly higher in the patient group (3.02 +/- 0.52 mm) compared to the control group (1.84 +/- 0.45 mm) (P < 0.001). Furthermore, there was a negative correlation (81.0%) between PON1 activity and carotid plaque in the overall study group (P < 0.05). Also serum homocystein level was higher in the patient group (22.15 +/- 7.05) compared to the control group (13.30 +/- 3.32). In conclusion, our findings show inverse association between PON1 activity and carotid atherosclerosis in Alzheimer patients: the lower the PON1 activity the more progressed the atherosclerotic process in AD. (C) 2016 Polish Neurological Society. Published by Elsevier Sp. z o.o. All rights reserved.