Browsing by Author "Selek, Sahbettin"

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Evaluation of Oxidative Status in Patients With Hyperthyroidism
(Humana Press inc, 2011) Aslan, Mehmet; Cosar, Niyet; Celik, Hakim; Aksoy, Nurten; Dulger, Ahmet Cumhur; Begenik, Huseyin; Selek, Sahbettin
Data on the antioxidant levels enzyme in patients with hyperthyroidism are limited and conflicting. Therefore, the objective of this study was to evaluate the oxidative status using an automated method in patients with hyperthyroidism. Thirty-six subjects with hyperthyroidism and 30 healthy controls were enrolled in this study. Serum oxidative status was determined via measurement of total antioxidant capacity (TAC) and total oxidant status (TOS) and calculation of oxidative stress index (OSI). Serum TAC levels were significantly lower in patients with hyperthyroidism than controls (P = 0.002), while serum TOS levels and OSI values were significantly higher (P = 0.008, 0.004; respectively). Serum TAC levels were correlated with TSH levels (rho = 0.223, P = 0.032), FT3 levels (rho = -0.434, P = 0.002) and FT4 levels (rho = -0.363, P = 0.003) in patients. Further, TOS levels and OSI values were correlated with TSH levels (rho = -0.245, P = 0.037; rho = -0.312, P = 0.011, respectively), FT3 levels (rho = 0.293, P = 0.017, rho = 0.505, P = 0.002, respectively), and FT4 levels (rho = 0.302, P = 0.006, rho = 0.321, P = 0.008, respectively) in patients. Duration of disease was significantly correlated with OSI values in patients (rho = 0.420, P = 0.011), while no correlation with serum TAC levels and TOS levels (P > 0.05). Oxidants are increased and antioxidants are decreased in patients with hyperthyroidism; as a result, the oxidative-antioxidative balance is shifted to the oxidative side. Increased oxidative stress may play a role in the pathogenesis of hyperthyroidism. It is believed that supplementation of antioxidant vitamins such as vitamins C and E may be helpful for these patients.
Protective Effects of Melatonin on Oxidative-Antioxidative Balance and Cataract Formation in Rats
(Amer Soc Contemporary Medicine Surgery & Ophthalmology, 2008) Kilic, Adil; Selek, Sahbettin; Erel, Oezcan; Aksoy, Nurten
We investigated the effects of melatonin on cataract formation in rats exposed to selenite. We concluded that the imbalance between oxidants and antioxidants plays an important role in cataract formation and melatonin decreases cataract incidence in rats by increasing antioxidant activity.
Serum Paraoxonase Activity, Total Thiols Levels, and Oxidative Status in Patients With Acute Brucellosis
(Springer Wien, 2015) Esen, Ramazan; Aslan, Mehmet; Kucukoglu, Mehmet Emin; Cikman, Aytekin; Yakan, Umit; Sunnetcioglu, Mahmut; Selek, Sahbettin
It is well known that paraoxonase-1 (PON1) activity may decrease during the course of infection and inflammation. The aim of this study was to investigate serum PON1 activity, oxidative status, and thiols levels in patients with acute brucellosis. In addition, we investigated the PON1 phenotype in patients with acute brucellosis. Thirty patients with acute brucellosis and 35 healthy controls were enrolled. Serum paraoxonase and arylesterase activities, thiols levels, lipid hydroperoxide levels, total antioxidant capacity (TAC), total oxidant status (TOS) and oxidative stress index (OSI) were determined. Serum basal and salt-stimulated paraoxonase-arylesterase activities, TAC levels and thiols levels were significantly lower in patients with acute brucellosis than controls (for all, p < 0.05), while LOOH levels, TOS levels, and OSI values were significantly higher (for all, p < 0.05). We concluded that oxidative stress is increased, while serum PON1 activity is decreased in patients with acute brucellosis. These results indicate that lower PON1 activity is associated with oxidant-antioxidant imbalance.
Serum Paraoxonase and Arylesterase Activities and Oxidant Status in Patients With Brucellosis
(Academic Journals, 2011) Karsen, Hasan; Karahocagil, Mustafa Kasim; Akdeniz, Hayrettin; Ceylan, Mehmet Resat; Binici, Irfan; Selek, Sahbettin; Celik, Hakim
The aim of this study was to the investigate the effect of brucellosis infection on paraoxonase-1 (PON1) activity and oxidative status in patients with brucellosis. Sixty patients with brucellosis (47 acute, 13 subacute) and the 67 healthy controls were used in the study. Serum PON1 and arylesterase activities, total antioxidant capacity (TAC), total oxidant status (TOS), oxidative stress index (OSI), total free sulfhydryl (-SH), and lipid hydroperoxide (LOOH) groups were determined. In addition, HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), total cholesterol (TC) and triglyceride (TG) were measured. Serum PON1 and arylesterase activities, total -SH group levels and TAC were significantly lower in brucellosis patients than controls (P<0.001). TOS, OSI and LOOH levels were significantly higher in brucellosis patients than controls (P<0.001). There were no significant differences between of serum LDL-C, TG and TC levels of patients subjects compared to controls (P > 0.05). Patients with brucellosis are exposed to potent oxidative stress and they have decreased PON1 activity. These predisposal factors might play a role in the pathogenesis for atherosclerosis in patients with brucellosis.