Ozgurk Tuncel - Academia.edu (original) (raw)

Papers by Ozgurk Tuncel

Psychiatry Research, 2015

Oxidative stress has an important place in studies investigating the pathophysiology of psychiatr... more Oxidative stress has an important place in studies investigating the pathophysiology of psychiatric diseases. In spite of this fact, longitudinal studies are required to clarify the subject. Therefore, in this study, we examined lipid peroxidation, protein oxidation, total oxidized guanine species, superoxide dismutase (SOD) and total glutathione (GSH) levels in blood collected from adult bipolar patients (n=18) during manic and euthymic episodes, schizophrenic patients (n=18) during acute psychotic attack and remission phases and the control group (n=18). There was a significant increase in the level of lipid peroxidation in the bipolar disorder manic episode group (BD-ME) compared to control group. The level of protein oxidation was significantly higher in the schizophrenia acute psychotic attack group (SZ-APA) compared to the control group. The level of total oxidized guanine species was statistically higher in all psychiatric groups compared to the control group. There was no significant difference among the groups with regard to SOD and GSH. Consequently, we believe that lipid peroxidation may be effective in the pathogenesis of bipolar patients; that protein oxidation may be of importance in the pathogenesis of schizophrenia and that total oxidized guanine species may be crucial in the pathogeneses of both psychiatric disorders.

Endocrine Abstracts, 2013

Toxicology and industrial health, Jan 29, 2014

Bisphenol A (BPA) is a commonly used material in daily life, and it is argued to cause oxidative ... more Bisphenol A (BPA) is a commonly used material in daily life, and it is argued to cause oxidative stress in liver and ovarian tissue. α-Lipoic acid (ALA) and α-tocopherol (ATF), two of the most effective antioxidants, may play a role in preventing the toxic effect. Therefore, the purpose of this study was to examine the beneficial effects of ALA, ATF, and that of ALA + ATF combination on oxidative damage induced by BPA. Female Wistar rats were divided into five groups (control, BPA, BPA + ALA, BPA + ATF, and BPA + ALA + ATF). BPA (25 mg/kg/day), ALA (100 mg/kg/day), and ATF (20 mg/kg/day) were administered for 30 days. The levels of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT), liver malondialdehyde (L-MDA) and glutathione peroxidase (L-GPx), and ovarian malondialdehyde (Ov-MDA) and nitric oxide (Ov-NO) were significantly higher in the BPA-treated groups compared with the control group. The levels of AST and ALT decreased in the BPA + ALA, BPA + ATF, and...

Endocrine, 2013

The effects of hyperprolactinemia on metabolic parameters are not clear and a few data evaluating... more The effects of hyperprolactinemia on metabolic parameters are not clear and a few data evaluating adiponectin levels in prolactinoma and idiopathic hyperprolactinemia exist. The aim of this study was to evaluate the effects of hyperprolactinemia on body weight, insulin resistance, beta cell function, and leptin and adiponectin levels in premenopausal women with hyperprolactinemia. Forty premenopausal women with prolactinoma or idiopathic hyperprolactinemia were compared to 41 age-matched healthy premenopausal women with regard to body weight, body mass index, waist and hip circumferences, waist to hip ratio, fasting plasma glucose, insulin levels, insulin resistance measured by homeostasis model assessment (HOMA)-insulin resistance index, beta cell function measured by HOMA-β index, leptin and adiponectin levels. Plasma insulin levels and HOMA indexes (both insulin resistance and beta indexes) were significantly higher in hyperprolactinemic women. The other parameters were similar between both groups. There was a positive correlation between prolactin levels and fasting plasma glucose in hyperprolactinemic women. The results of this study showed that high prolactin levels may be associated with hyperinsulinemia and insulin resistance in premenopausal women. This effect seems to be independent of body weight, leptin and adiponectin levels. High prolactin levels may directly stimulate insulin secretion from pancreas and directly cause hepatic and whole-body insulin resistance.

Endocrine, 2014

VEGF is a specific mitogen for endothelial cells. GM-CSF is a key player in the regulation of ste... more VEGF is a specific mitogen for endothelial cells. GM-CSF is a key player in the regulation of steady-state functions. The aim of this study was to evaluate VEGF and GM-CSF levels in thyroid nodules &amp;amp;amp;amp;amp;gt;1 cm, which are negative for malignancy with fine needle aspiration biopsy. Age, serum VEGF, GM-CSF, TSH, fT3, fT4, anti-TG, anti-TPO, thyroid size, and thyroid volume were compared between 41 female patients and 20 healthy female volunteers. This study was performed with 41 female patients who were euthyroid and whose nodules were benign. Twenty healthy female volunteers were enrolled as the control group. VEGF and GM-CSF were assayed by ELISA; TSH, fT3, and fT4 were detected by electrochemiluminescence method and anti-TPO and anti-TG were detected by competitive immunoassay method. Only thyroid volume and anti-TG levels were significantly different between the two groups (p &amp;amp;amp;amp;amp;lt; 0.007 and p &amp;amp;amp;amp;amp;lt; 0.026, respectively). Other parameters including VEGF and GM-CSF were not significantly different. VEGF has a weak positive correlation only with anti-TPO levels in the patient group (r = 0.325, p = 0.036). There was a weak positive correlation between anti-TPO and anti-TG (r = 0.388, p = 0.007). There was a positive correlation between nodule size and thyroid volume (r = 0.464, p = 0.015). GM-CSF was not correlated with any parameters. VEGF and GM-CSF were not found to be increased in euthyroid patients with benign nodules and they do not seem to play a role in development of simple nodular goiter.

Electromagnetic Biology and Medicine, 2013

The increasing use of mobile telephones raises the question of possible adverse effects of the el... more The increasing use of mobile telephones raises the question of possible adverse effects of the electromagnetic fields (EMF) that these phones produce. In this study, we examined the oxidative stress in the brain tissue and serum of rats that resulted from exposure to a 900-MHz EMF at a whole body average specific absorption rate (SAR) of 1.08 W/kg for 1 h/day for 3 weeks. We also examined the antioxidant effect of garlic powder (500 mg/kg/day) given orally to EMF-exposed rats. We found that malondialdehyde (MDA) ( p , 0.001) and advanced oxidation protein product (AOPP) ( p , 0.05) increased in rat brain tissue exposed to the EMF and that garlic reduced these effects ( p , 0.05). There was no significant difference in the nitric oxide (NO) levels in the brain. Paraoxonase (PON) was not detected in the brain. There was a significant increase in the levels of NO ( p , 0.001) detected in the serum after EMF exposure, and garlic intake did not affect this increase in NO. Our results suggest that there is a significant increase in brain lipid and protein oxidation after electromagnetic radiation (EMR) exposure and that garlic has a protective effect against this oxidative stress.

African Journal of Paediatric Surgery, 2013

Insulin has been reported to have positive effects on intestinal adaptation after short bowel syn... more Insulin has been reported to have positive effects on intestinal adaptation after short bowel syndrome when applicated oral or subcutaneously. The purpose of this study is to compare the intestinal adaptation effects of subcutaneous and oral routes of insulin in rats with short bowel syndrome. The short bowel syndrome (SBS) was performed through 70-75% of small intestinal resection and an end-to-end anastomosis. The control group rats underwent SBS only. In the second group, oral insulin (1 U/ml) was administrated twice-daily. In the last group, the insulin was administrated subcutaneously (1 U/kg) as in the control group. All rats were killed on day 15. Outcome parameters were weight of small intestine, the crypt length, villous depth, the blood levels of vascular endothelial growth factor (VEGF), and granolocyt-monocyst colony-stimulating factor (GMCSF). Intestinal weight was significantly more in oral insulin group and subcutaneous insulin group than in the control group (72.6 ± 4.3, 78.6 ± 4.8 and 59.7 ± 4.8) (P &amp;amp;amp;lt; 0.05). There was no difference between the groups according to villus length, crypt depth, and villous/crypt ratio both in proximal and distal parts of the resected bowel (P &amp;amp;amp;gt; 0.05). VEGF values were not statistically significant between the groups (200.3 ± 41.6, 178.9 ± 30.7 and 184.3 ± 52.2) (P &amp;amp;amp;gt; 0.05). GMCSF was statistically higher in the control group than in other groups (3.34 ± 1.34, 1.56 ± 0.44 and 1.56 ± 0.44) (P &amp;amp;amp;lt; 0.05). Insulin has positive effects on intestinal adaptation in short bowel syndrome. Subcutaneous administration is slightly more effective than the oral route.

Journal of Applied Toxicology, Jul 1, 2008

A chronic intake of high dose alcohol may cause oxidative stress and inflammation in the stomach.... more A chronic intake of high dose alcohol may cause oxidative stress and inflammation in the stomach. It is hypothesized that cysteine-methionine and vitamin C may neutralize harmful compounds while potentiating the antioxidant capacity of the cell or tissue. The experimental animals were fed regular diets and were maintained for 90 days in the control group, the alcoholic group, which was given 2.5 g of 50% ethanol kg − − − − −1 body wt. administered intragastrically every other day, or the alcoholic with antioxidant supplement group, to whom 2.5 g of 50% ethanol kg − − − − −1 body wt. + + + + + a solution that contained 200 mg vitamin C, 100 mg cysteine and 100 mg methionine was administered intragastrically every other day. After the treatments, the stomach was taken for pathological and biochemical analysis. The stomach of the alcoholic group rats had higher scores of pathological findings compared with the control group, whereas the scores of the antioxidant-supplemented group were lower than the alcoholic group. In addition, the oxidized protein and lipid content in the stomachs of the alcoholic group were significantly higher than the control, but antioxidant supplementation lowered the amount of oxidation in the antioxidant supplemented group. The amount of stomach glutathione in the alcoholic group was higher than that of the control and antioxidant-supplemented groups. Interestingly, the level of total thiol in the stomach tissue of rats with antioxidant supplement was statistically higher than that of the control and alcoholic groups. In conclusion, the scores of the pathological findings in the stomach of rats with the antioxidant supplement were lower than the chronic alcohol-treated rats, albeit the amount of total thiol was increased in this group. Moreover, chronic alcohol treatment led to an increase in the level of lipid and protein oxidation in the stomach tissue of rats. A simultaneous intake of ascorbate/L-cys/L-met along with ethanol attenuated the amount of oxidation which suggested that cysteine-methionine and vitamin C could play a protective role in the stomach against oxidative damage resulting from chronic alcohol ingestion.