Are you Ozgur Akgul?

Claim your profile

Publications (6)9.28 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: It has been demonstrated that peroxynitrite accompanies acute renal ischemia and contributes to the pathophysiology of renal damage. Therefore, we aimed to investigate the roles of N-acetylcysteine (NAC), a well-known powerful antioxidant, and ebselen (E), a scavenger of peroxynitrite, on renal injury induced by renal ischemia/reperfusion injury (IRI) of rat kidney. Forty male Sprague-Dawley rats were divided into five groups: sham, renal IRI, renal IRI+NAC, renal IRI+E, and renal IRI+NAC+E. IR injury was induced by 60 min of bilateral renal ischemia followed by 6 h of reperfusion. After reperfusion, kidneys and blood samples were obtained for histopathological and biochemical evaluations. Renal IR resulted in increased malondialdehyde and nitrite/nitrate levels suggesting increased lipid peroxidation and peroxynitrite production and decreased superoxide dismutase and glutathione peroxidase activities. Both NAC and E alone significantly decreased malondialdehyde and nitrite/nitrate levels and increased superoxide dismutase and glutathione peroxidase activities. Additionally in the renal IRI+NAC+E group, all biochemical results were quite close to those of sham group. Histopathologically, the kidney injury in rats treated with combination of NAC and E was found significantly less than the other groups. Both NAC and E are able to ameliorate IRI of the kidney by decreasing oxidative and nitrosative stresses and increasing free radical scavenger properties. Additionally, combination of NAC and E prevents kidney damage more than when each drug is used alone, suggesting that scavenging peroxynitrite nearby antioxidant activity is important in preventing renal IRI.
    Renal Failure 01/2011; 33(5):512-7. · 0.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In large dosages, acetaminophen (APAP) produces acute kidney necrosis in most mammalian species. High neopterin levels have been accepted as strong indicators for the clinical severity of some diseases. In this study, we aimed to evaluate whether neopterin is a biomarker in the identification of APAP-induced nephrotoxicity. Thirty adult male Wistar rats were randomly divided into three groups: control, APAP-1, and APAP-2 groups. APAP-1 and APAP-2 group rats were given a single dose of 1 and 2 g/kg body weight of APAP by gastric tube, respectively. Kidney tissues and blood samples were obtained for biochemical and histopathological analyses. Biochemical parameters, serum and kidney neopterin levels, and the grade of tubular injury were compared in the control, APAP-1, and APAP-2 group animals. APAP treatments caused tubular necrosis in the kidney and increase in serum creatinine concentrations accompanied by elevated serum and kidney neopterin levels. In the rats of groups APAP-1 and APAP-2 when compared with that of the control group (109.1 pmol/mg protein), median kidney neopterin concentrations were 162.1 (p = 0.089) and 222.2 (p < 0.001) pmol/mg protein, respectively. The grade of tubular injury of the APAP-1 and APAP-2 groups was higher than the group of control (both p < 0.001). Serum and kidney neopterin levels could be sensible alternative to evaluate the risk to have nephrotoxicity because of APAP overdose. The elevated serum and kidney neopterin in the APAP-induced tubular necrosis might be a marker of acute histological kidney injury.
    Renal Failure 07/2010; 32(6):740-6. · 0.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Several natural products have been reported to have beneficial effects on ischemia/reperfusion (I/R) injury, particularly from a preventative perspective. Therefore, this study was designed to investigate the efficiency of proanthocyanidin (PA), a natural product derived from grape seed, on renal dysfunction and injury induced by I/R of rat kidney. Twenty-four male Sprague-Dawley rats were divided into three groups: sham-operated, I/R, I/R+PA. Rats were given PA (100 mg/kg/day peroral) 7 days prior to I/R. All rats except sham-operated underwent 60 min of bilateral renal ischemia followed by 6 h of reperfusion. After reperfusion, kidneys and blood were obtained for evaluation. Superoxide dismutase, glutathione peroxidase, malondialdehyde, protein carbonyl content, and nitrite/nitrate level (NO(x)) were determined in the renal tissue. Serum creatinine (S(Cr)), blood urea nitrogen (BUN), and aspartate aminotransferase (AST) were determined in the blood. Additionally, renal sections were used for histological grade of renal injury. PA significantly reduced the I/R-induced increases in S(Cr), BUN, and AST. In addition, PA markedly reduced elevated oxidative stress product, restored decreased antioxidant enzymes, and attenuated histological alterations. Moreover, PA attenuated the tissue NO(x), levels indicating reduced NO production. The pretreatment of rats with PA reduced the renal dysfunction and morphological changes, ameliorated cellular injury, and restored renal antioxidant enzymes caused by renal I/R.
    Renal Failure 02/2008; 30(9):931-8. · 0.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Nitric oxide (NO) and peroxynitrite (OONO-) are implicated in the pathophysiology of renal ischemia/reperfusion (I/R). The aim of this study was to investigate and compare the efficiency of S-methylisothiourea (SMT), an iNOS inhibitor, and mercaptoethylguanidine (MEG), a scavenger of peroxynitrite, on renal dysfunction and injury induced by I/R of rat kidney. Thirty-two male Sprague-Dawley rats were divided into four groups: sham-operated, I/R, I/R+SMT, and I/R+MEG. Rats were given SMT (10 mg/kg i.p.) or MEG (10 mg/kg i.p.) 6 h prior to I/R and at the beginning of reperfusion. All rats except sham-operated underwent 60 min of bilateral renal ischemia followed by 6 h of reperfusion. After reperfusion, kidneys and blood were obtained for evaluation. Superoxide dismutase, glutathione peroxidase, malondialdehide, protein carbonyl content, and nitrite/nitrate level (NO(x)) were determined in the renal tissue. Serum creatinine (S(Cr)), blood urea nitrogen (BUN), and aspartate aminotransferase (AST) were determined in the blood. Additionally, renal sections were used for histological grade of renal injury. SMT and MEG significantly reduced the I/R-induced increases in S(Cr), BUN, and AST. Both SMT and MEG attenuated the tissue NO(x) levels, indicating reduced NO production. In addition, SMT and MEG markedly reduced elevated oxidative stress product, restored decreased antioxidant enzymes, and attenuated histological alterations. Interestingly, MEG exerted a greater renoprotective effect than SMT. These data support the finding that iNOS and peroxynitrite are involved in the renal I/R injury, and suggest that a scavenger of peroxynitrite might be more effective than iNOS inhibitors as a therapeutic intervention.
    Renal Failure 02/2008; 30(7):747-54. · 0.94 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pulmonary department of a medical academy in Ankara, Turkey. Neopterin is a marker of cell-mediated immunity, and it has been demonstrated that neopterin levels of various body fluids could be elevated in tuberculosis. We aimed to investigate diagnostic values of serum, pleural fluid and urine neopterin measurements in tuberculous pleurisy (TP). Serum, pleural fluid and urine neopterin levels were measured in 34 patients with TP and in 29 patients with pleural effusion of non-tuberculous origin as controls. Neopterin levels in serum, pleural fluid and urine (38.28 +/- 14.18 nmol/l, 38.97 +/- 14.18 nmol/l and 759.15 +/- 622.74 micromol/mol, respectively) were significantly higher in patients with TP than those with non-tuberculous pleural effusion (22.57 +/- 6.02 nmol/l, 21.88 +/- 6.90 nmol/l and 343.10 +/- 233.65 micromol/mol, respectively). Pleural fluid neopterin > or =30 mol/l gave the best diagnostic yield, with 85% sensitivity, 93% specificity, 94% positive predictive value, 84% negative predictive value and 89% diagnostic accuracy, although it is not superior to pleural fluid adenosine deaminase determination. We have suggested that elevated serum, pleural fluid and urinary neopterin levels in TP with respect to pleural effusions of non-tuberculous origin may reflect activation of cell-mediated immunity and that pleural fluid neopterin measurement may be of value in the differential diagnosis of TP.
    The International Journal of Tuberculosis and Lung Disease 10/2005; 9(9):1040-5. · 2.76 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pulmonary department of a university hospital in Ankara, Turkey. To investigate the usefulness of neopterin in pulmonary tuberculosis (PTB) as a rapid diagnostic tool. Neopterin concentrations in bronchoalveolar lavage fluid (BAL), serum and urine were measured in patients with PTB, with lung cancer and with pneumonia and in a healthy control group. In the BAL of PTB patients, serum and urine levels of neopterin were significantly higher than all the other groups (P < 0.001). Compared with the lung cancer group, PTB patients had higher neopterin in BAL and urine (P < 0.05). The PTB group had higher levels not only in BAL and urine, but also in serum, than the pneumonia group (P < 0.05). Compared with the pneumonia group and the healthy controls, neopterin levels in serum and urine were significantly higher in the lung cancer group (P < 0.05). In the PTB group, patients with moderately advanced PTB according to radiographic extent had higher levels of urine neopterin than patients with minimal disease (P = 0.01). Neopterin levels in BAL, serum and particularly in urine may reflect PTB activity before exact diagnosis of the disease by culture results, and correlates with radiological extent.
    The International Journal of Tuberculosis and Lung Disease 09/2003; 7(8):771-6. · 2.76 Impact Factor