Browsing by Author "Tamer, Sibel"

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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; Gonullu, Edip
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 Blood samples were withdrawn from the patients and healthy controls, and the activities of antioxidant enzymes SOD (Superoxide Dismutase), GSH (Glutathion), GSHPx (Glutathion peroxidase),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.
Lateralization of Neurobiological Response in Adolescents With Post-Traumatic Stress Disorder Related To Severe Childhood Sexual Abuse: the Tri-Modal Reaction (t-Mr) Model of Protection
(Routledge Journals, Taylor & Francis Ltd, 2018) Mutluer, Tuba; Sar, Vedat; Kose-Demiray, Cigdem; Arslan, Harun; Tamer, Sibel; Inal, Serap; Kacar, Anil S.
This study inquires into neurobiological response to stress and its clinical correlates among adolescents with post-traumatic stress disorder (PTSD). Structural magnetic resonance imaging (MRI) measures of cerebral anatomy were carried out on 23 female adolescents with PTSD related to severe childhood sexual abuse and 21 matched healthy controls. Clinician Administered PTSD Scale for Children and Adolescents, Adolescent Dissociative Experiences Scale, Childhood Trauma Questionnaire, Schedule for Affective Disorders and Schizophrenia for School Age Children, Beck Depression Scale, and a set of neuro-cognitive tests were administered to all participants. Compared to controls, PTSD group bilaterally had smaller amygdala, hippocampus, anterior cingulate, and thinner prefrontal cortex but normal thalamus. Further analyses within the PTSD group suggested an association between symptoms of PTSD and sizes of right brain structures including smaller amygdala but larger hippocampus and anterior cingulate. Thinner right prefrontal cortex and larger right thalamus seemed to be related to denial and response prevention, respectively. Being related to both hemispheres, dissociative amnesia was negatively associated with proportion of the right amygdala to right thalamus and to both left and right prefrontal cortex. Suggesting a neuro-protective effect against traumatic stress at least through adolescence, depersonalization-derealization and identity alteration were correlated with thicker left prefrontal cortex. Unlike the lateralization within PTSD group, correlations between regions of interest were rather symmetrical in controls. The graded response to stress seemed to be aimed at mental protection by lateralization of brain functions and possibly diminished connection between two hemispheres. A Tri-Modal Reaction (T-MR) Model of protection is proposed.
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.