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Dive into the research topics where Mehmet Can Akyolcu is active.

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Featured researches published by Mehmet Can Akyolcu.


Biological Trace Element Research | 2007

High Levels of Cadmium and Lead in Seminal Fluid and Blood of Smoking Men are Associated with High Oxidative Stress and Damage in Infertile Subjects

Ali Riza Kiziler; Birsen Aydemir; Ilhan Onaran; Bulent Alici; Hamdi Özkara; Tevfik Gulyasar; Mehmet Can Akyolcu

We measured the levels of malondialdehyde (MDA), protein carbonyls, glutathione S-transferase (GST) and reducte glutathione (GSH) in seminal plasma and spermatozoa from 95 subjects including 50 infertile patients to evaluate the association between oxidative stress and damage and the components of the anti-oxidant defenses in seminal plasma and spermatozoa of infertile subjects and concentrations of cadmium (Cd) and lead (Pb) in the blood and seminal plasma because of tobacco smoke exposure. The reactive oxygen species (ROS) in spermatozoa were also evaluated by luminol (5-amino-2,3-dihydro-1,4-phthalazinedione)-enhanced chemiluminescence assay. The sperm count, motility, and morphology in the smokers infertile group were found to be lower than those in the fertile male group and nonsmokers infertile group (p < 0.001). Concentrations of Cd, Pb, MDA, protein carbonyls, and ROS levels in the smokers infertile group were significantly higher than those in the fertile male and nonsmokers infertile male groups (p < 0.001). However, GSH levels and GST activities were decreased in the smokers infertile male group than those in the fertile male and nonsmokers infertile male groups (p < 0.001). The results indicate that smoking could affect semen quality and oxidative lipid and protein damage in human spermatozoa. From Pearson correlation analysis, positive correlations were demonstrated between the seminal plasma Cd and seminal plasma protein carbonyls and between seminal plasma Pb and spermatozoa ROS levels in smokers of the subfertile group, while there was a significant positive correlation between blood Cd and ROS levels in smokers of the fertile group. There was also a significant negative correlation of the Cd level of the blood and GSH levels of the sperm and seminal plasma. These findings suggest that cigarette smoking enhances the levels of Cd and Pb in seminal plasma and blood and the extent of oxidative damage associated with a decrease in components of the anti-oxidant defenses in the sperm of infertile males.


Biological Trace Element Research | 2006

Impact of Cu and Fe concentrations on oxidative damage in male infertility

Birsen Aydemir; Ali Riza Kiziler; Ilhan Onaran; Bulent Alici; Hamdi Özkara; Mehmet Can Akyolcu

Oxidative stress in the reproductive system is thought to have an effect on the fertilizing ability of sperm. The purpose of this study was to assess the interaction of iron (Fe) and copper (Cu) ions in suspected subfertile and fertile male groups and to find out the relationships of the semen parameters (sperm count, motility, and abnormal morphology), glutathione, malondialdehyde, and reactive oxygen species with these variables. Semen and blood obtained from 60 subfertile men and from 40 fertile volunteers were examined. The sperm count and motility in the subfertile male group were found lower than those in fertile male group (p<0.001). Cu levels in serum and seminal plasma in the subfertile male group were significantly higher than those in the fertile male group (p<0.001 and p<0.05, respectively). There was also a significant increase in the Fe level of seminal plasma in the subfertile male group (p<0.001). However, there was no significant difference in the Fe level of serum in the subfertile male group. In conclusion, these findings suggest that Cu and Fe might be mediators of the effects of oxidative damage and play an essential role in spermatogenesis and male infertility; the determination of Fe and Cu levels in serum and seminal plasma during infertility investigation is recommended.


Endocrine | 2004

Erythrocyte osmotic fragility and oxidative stress in experimental hypothyroidism.

Nuran Dariyerli; Selmin Toplan; Mehmet Can Akyolcu; Hüsrev Hatemi; Günnur Yigit

The present study was planned to explain the relation between erythrocyte osmotic fragility and oxidative stress and antioxidant statue in primary hypothyroid-induced experimental rats. Twenty-four Spraque Dawley type female rats were divided into two, as control (n=12) and experimental (n=12), groups weighing between 160 and 200 g. The experimental group animals have received tap water methimazole added standard fodder to block the iodine pumps for 30 d (75 mg/100 g). Control group animals were fed tap water and only standard fodder for the same period. At the end of 30 d blood samples were drawn from the abdominal aorta of the rats under ether anesthesia. T3, T4, and TSH levels were measured and the animals that had relatively lower T3, T4, and higher TSH levels were accepted as hypothyroid group. Hormone levels of the control group were at euthyroid conditions. Osmotic fragility, as a lipid peroxidation indicator malondialdehyde (MDA), antioxidant defense system indicators superoxide dismutase (SOD) and glutathione (GSH) levels were measured in the blood samples. Osmotic fragility test results: There was no statistically significant difference found between maximum osmotic hemolysis limit values of both group. Minimum osmotic hemolysis limit value of hypothyroid group was found to be higher than that of control group values (p<0.02). The standard hemolysis and hemolytic increment curve of the hypothyroid group drawn according to osmotic fragility test results was found to be shifted to the right when compared to control group’s curve. This situation and hemolytic increment value, which shows maximum hemolysis ratio, is the proof of increased osmotic fragility of the erythrocytes in hypothyroidism. There is no statistically significant difference found between hypothyroid and control groups in the lipid peroxidation indicator MDA and antioxidant indicators SOD and GSH levels. As a result of our study it may be concluded that hypothyroidism may lead to an increase in osmotic fragility of erythrocytes. But the increase in erythrocyte osmotic fragility does not originate from lipid peroxidation.


Endocrine | 2005

The effects of experimental hyperthyroidism on hemorheology and plasma fibrinogen concentration.

Semra Özdemir; Rıfat Yücel; Nuran Dariyerli; Selmin Toplan; Mehmet Can Akyolcu; Günnur Yigit; Hüsrev Hatemi

The present study in female rats determined the effects of experimental hyperthyroidsm on hemorheological parameters and fibrinogen concentration. To induce experimental hyperthyroidism l-thyroxine (0.4 mg/100 g fodder) was added to the fodder of the experimental group rats for 20 d. After experimental duration, T3, T4, and TSH levels, plasma and blood viscosity, hematocrit, erythrocyte rigidity index, and plasma fibrinogen concentration values of both the control and the experimental group animals were determined and evaluated. In the experimental group, T3 and T4 levels were higher and TSH levels lower than that of the control rats (respectively, p<0.01, p<0.001, p<0.001). Plasma viscosity and fibrinogen concentration of hyperthyroid group were found significantly higher than controls (p<0.01). However there was no significant difference found in blood viscosity, hematocrit, and erythrocyte rigidity index between control and experimental groups. Thus, hyperthyroidism induced increased fibrinogen concentration can alter the rheological structure of blood by inducing increase in plasma viscosity.


Fertility and Sterility | 2003

Plasma viscosity as an early cardiovascular risk factor in hirsute women with eumenorrhea or oligomenorrhea

Necmiye Tijen Erdem; Meltem Ercan; Mehmet Can Akyolcu; A.Sadi Gündoğdu

To investigate plasma viscosity, a hemorheologic variable, in oligomenorrheic and eumenorrheic hirsute women.Descriptive study. Endocrinology and metabolism clinic. Twenty five hirsute women with oligomenorrhea and eumenorrhea and 30 age- and weight-matched healthy, eumenorrheic, nonhirsute women. Plasma viscosity. Plasma viscosity was significantly elevated in hirsute women compared with eumenorrheic nonhirsute women. Significant correlations were observed between plasma viscosity and fasting insulin level, cholesterol level, and diastolic blood pressure. Hirsute women with oligomenorrhea or eumenorrhea had a significantly elevated plasma viscosity compared with healthy controls.


Biological Trace Element Research | 2002

Effects of excessive copper intake on hematological and hemorheological parameters.

Derviş Özçelik; Selmin Toplan; Semra Özdemir; Mehmet Can Akyolcu

Copper plays an important role in the structure and function of metalloproteins and in the absorption of iron. The present study deals with the effects of excessive copper intake on hematological and hemorheological parameters.Drinking water containing 250 µg/mL copper for a period of 9 wk, Wistar albino rats showed increased erythrocyte count, blood viscosity, and hematocrit values (p<0.05) and lower hemoglobin (p<0.05) than controls fed a normal diet. The two groups also had differences in the erythrocyte deformability index.The results suggest that excessive copper intake results in hematological and hemorheological changes affecting both the protein content of the erythrocyte membrane and heme synthesis.


Oncology Letters | 2018

Monitoring of platelet function parameters and microRNA expression levels in patients with prostate cancer treated with volumetric modulated arc radiotherapy

Nurten Bahtiyar; Ilhan Onaran; Birsen Aydemir; Onur Baykara; Selmin Toplan; Fulya Yaman Agaoglu; Mehmet Can Akyolcu

Radiotherapy (RT) may result in platelet activation and thrombosis development. To the best of our knowledge, the potential effect of volumetric-modulated arc therapy (VMAT), a novel radiotherapy technique, on platelet function and microRNA (miRNA/miR) expression has not been previously investigated. The present study aimed to determine the effect of VMAT on the alterations in platelet function parameters and miRNA expression levels. A total of 25 patients with prostate cancer and 25 healthy subjects were included in the present study. Blood samples were collected from the patient group on the day prior to RT (pre-RT), the day RT was completed (post-RT day 0), and 40 days following the end of therapy (post-RT day 40). Platelet count, mean platelet volume (MPV) value, platelet aggregation, plasma P-selectin, thrombospondin-1, platelet factor 4, plasma miR-223 and miR-126 expression levels were measured. A significant decrease in platelet count in the post-RT day 0 group was measured in comparison with the pre-RT and the post-RT day 40 groups. Pre-RT MPV values were higher than those of the post-RT day 0 and the post-RT day 40 groups. No significant differences were observed in the levels of platelet activation markers or miR-223 and miR-126 expression levels between the RT groups. Although RT may result in a reduction in platelet and MPV counts, the results of the present study indicate that platelet activation markers are not affected by VMAT. Therefore, it is possible that no platelet activation occurs during VMAT, owing to the conformal dose distributions, improved target volume coverage and the sparing of normal tissues from undesired radiation.


SIXTH INTERNATIONAL CONFERENCE OF THE BALKAN PHYSICAL UNION | 2007

Impact of Testosterone, Zinc, Calcium and Magnesium Concentrations on Sperm Parameters in Subfertile Men

Birsen Aydemir; Ali Riza Kiziler; Ilhan Onaran; Bulent Alici; Hamdi Özkara; Mehmet Can Akyolcu

To investigate the impact of testosterone, zinc, calcium and magnesium concentrations in serum and seminal plasma on sperm parameters. There were significant decrease in sperm parameters, serum and seminal plasma zinc levels in subfertile males. It indicates zinc has a essential role in male infertility; the determination the level of zinc during infertility investigation is recommended.


SIXTH INTERNATIONAL CONFERENCE OF THE BALKAN PHYSICAL UNION | 2007

Effect of Cigarette Smoking on Concentrations of Cadmium and Lead and on the Oxidative Damage in Human Spermatozoa

Ali Riza Kiziler; Birsen Aydemir; Ilhan Onaran; Bulent Alici; Hamdi Özkara; Mehmet Can Akyolcu

Cigarette smoking induced a significant oxidant effect to free radical‐related male infertility. Semen and blood obtained from 50 subfertile men (n=26 smokers, n=24 nonsmokers) and from 45 fertile men (n=23 smokers, n=22 nonsmokers) volunteers were examined. The levels of ROS, MDA and protein carbonyls were significantly increased in smokers subfertile men. The results indicate that Cd and Pb levels of smoking subfertile men in seminal plasma and spermatozoa could affect semen quality and oxidative damage in human sperm cells.


Trace Elements and Electrolytes | 2003

Study on relation between fibrinolytic activity and different dose lithium applications

Selmin Toplan; Derviş Özçelik; Mehmet Can Akyolcu

Introduction and purpose: Lithium is an element that has been widely used in therapy of mental diseases. In different studies it has been shown that it interacts with enzymes and alters the function of proteins in organisms. On the other hand fibrinogen is one of the plasma proteins that can interact with euglobulin which is the tissue plasminogen activator indicator. Present study was planned to assess the effect of lithium on alteration of function of proteins that play a role in the fibrinolytic system in blood. Materials and methods: Control group of rats was fed a normal diet whereas pharmacological and toxic groups received 0.4 mmolLi/kg/day and 6.6 mmolLi/ kg/day for 2 weeks, respectively. Blood samples were drawn from animals and fibrinolytic activity was measured by Coppley method, which is based on the euglobulin lysis time (ELT). Fibrinogen concentration determinations were performed by Ratnoff and Menzie method. Results and conclusion: After evaluation of fibrinolytic activity rates that belong to both groups, it has been observed that lithium altered the activities of proteins that are responsible for fibrinolysis. Fibrinogen concentrations of both experimental groups were found to be lower than that of control group values (p < 0,05 in pharmacological group, p < 0.001 in the toxic group). On the other hand ELT values in the toxic dose lithium administered group was significantly shortened than control group values (p < 0.001).

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