Sabiha Civelek

Evaluation of oxidative stress parameters in blood of patients with laryngeal carcinoma.

OBJECTIVES In this study, plasma lipid peroxidation as assessed by thiobarbituric acid reactive substances and erythrocyte antioxidant status markers namely CuZn superoxide dismutase, glutathione peroxidase, glutathione and plasma levels of vitamin C and E were investigated in 20 patients with larygneal carcinoma and 15 healthy controls. DESIGN AND METHODS Lipid peroxidation was observed to be significantly higher (0.01 > p > 0.001) in the larynx carcinoma group in comparison to the healthy controls. Both stage I + 11 and stage III carcinoma patients were observed to have significantly higher thiobarbituric acid reactive substances than the control group. A significant difference was found in plasma vitamin E level between the control group and stage I + 11 and stage III carcinoma patients (p < 0.01, 0.05 > p > 0.02, respectively). RESULTS Our findings reveal the presence of increased lipooxidative damage in laryngeal carcinoma patients, but no change with respect to the endogenous antioxidant components-GSH, GSH Px, and CuZn SOD.

The association of oxidative stress markers with conventional risk factors in the metabolic syndrome

BACKGROUND AND AIMS The metabolic syndrome (MetS) is a common and complex disorder that consists of various abnormalities, including dyslipidemia, obesity, hypertension and hyperglycemia. We investigated the relationships between the levels of advanced protein oxidation products (AOPPs), the total antioxidant capacity (TAC) and the pro-oxidant-antioxidant balance (PAB) in MetS patients. METHODS A total of 55 patients (37 women, 18 men) with MetS and 20 healthy controls (14 women, 6 men) with a body mass index (BMI) less than 25 kg/m(2) were enrolled in the study. Colorimetric methods were used to determine the levels of AOPPs, the TAC, and the PAB. RESULTS AOPP, TAC, and PAB values were significantly higher in patients with MetS than in control subjects (p<0.001, p=0.050, and p<0.001, respectively). A positive correlation was observed between the AOPP levels and the glucose, triglyceride, insulin and HOMA-IR levels. PAB values also exhibited significant positive correlations with diastolic blood pressure and fibrinogen levels. Logistic regression analysis revealed that higher serum PAB values were positively and independently associated with the MetS (odds ratio: 1.110; 95% confidence interval: 1.006-1.224; P<0.37). CONCLUSIONS Increased AOPP levels and higher PAB values are likely to be a result of oxidative stress, a condition in which an imbalance occurs between the production and inactivation of reactive oxygen species. In addition, it appears that serum PAB values may accurately reflect the levels of oxidative stress in MetS patients.

Oxidative stress in heart tissue of hyperthyroid and iron supplemented rats.

This study was designed to investigate the effect of hyperthyroidism and/or iron supplementation on cardiac oxidative stress parameters--the lipid peroxidation end product glutathione (GSH), glutathione peroxidase (GSH-Px), and superoxide dismutase (CuZnSOD)--in rats. In plasma, ferritin as an indicator of iron status and glutamate oxaloacetate transaminase (GOT) as an indicator of damage to the heart tissue were analyzed. Our findings show that hyperthyroidism increased lipooxidative damage as reflected by higher lipid peroxidation end product levels and elevated antioxidant defense parameters--GSH and GSH-Px. Iron supplementation per se does not affect oxidative stress parameters studied in the euthyroid state. Although iron increased lipid peroxidation in the hyperthyroid state, this effect was less than that seen in euthyroidism. Iron supplementation to hyperthyroid rats significantly lowered plasma ferritin levels, suggesting increased iron elimination with consequently reduced oxidative stress.

Effects of methylene blue in reducing cholestatic oxidative stress and hepatic damage after bile-duct ligation in rats

The aim of this study was to evaluate the effects of methylene blue against cholestatic oxidative stress and liver damage after ligation of the common bile duct in male Wistar rats. Eight animals were included in each of the following five groups: untreated control, methylene blue control, sham-operated, bile-duct ligation, and bile-duct ligation plus methylene blue. Methylene blue was administered intraperitoneally for 14 days at a daily dose of 2mg/kg per day. All rats were sacrificed 2 weeks following the experimental treatment and the livers of all groups were examined biochemically and histopathologically. The severity of cholestasis and hepatic injury were determined by changes in the plasma, including enzymatic activities: aspartate aminotransferase, alanine aminotransferase, gamma glutamine transferase, and also bilirubin levels. Malondialdehyde, nitric oxide and superoxide dismutase were measured to indicate the oxidative status in the liver tissue. Myeloperoxidase activity and levels of tissue hydroxyproline were determined as measures of neutrophil activation and collagen accumulation, respectively. Liver damage was significantly prevented in the bile-duct ligated rats treated with methylene blue compared with the control bile-duct ligated rats without methylene blue. Treatment with methylene blue markedly reduced activities of serum transaminase, gamma glutamine transferase and bilirubin levels as compared to bile-duct ligated rats without methylene blue. Positive immunolabelling for alpha-smooth muscle actin (alpha-SMA) was increased, especially in vascular smooth muscle cells, fibrotic septa and also around the proliferated bile ducts, after bile-duct ligation. Only weak alpha-SMA immunolabelling was seen in livers of rats treated with methylene blue. These results indicate that methylene blue can attenuate hepatic damage in extrahepatic cholestasis by reducing oxidative stress and inflammatory processes.

Oxidative damage to nuclear DNA in hyperthyroid rat liver: inability of vitamin C to prevent the damage.

The effects of hyperthyroidism on oxidative DNA damage in liver tissue and modification by vitamin C supplementation were investigated in rats. Animals were rendered hyperthyroid by administration of l-thyroxine (0.4 mg/100 g food) for 25 d. In the plasma samples, T3, T4, and thyroid-stimulating hormone (TSH) were measured by radioimmunoassay and ascorbate spectrophotometrically. Oxidative damage to hepatic nuclear DNA was determined by measuring deoxy-guanosine (dG) and 8-oxodG by high-performance liquid chromatography with diode array detector electrochemical detection (HPLC-DAD-ECD). In hyperthyroidism, 8-oxodG/ (105 dG) levels were significantly higher and plasma vitamin C levels lower than in control rats. The results of this experimental study show that oxidative damage to hepatic nuclear DNA increases in the hyperthyroid state and that vitamin C was not effective in preventing this damage.

Effects of sphingosylphosphorylcholine against cholestatic oxidative stress and liver damage in the common bile duct ligated rats.

The goal of this study was to evaluate the possible protective effects of sphingosylphosphorylcholine (SPC) against cholestatic oxidative stress and liver damage in the common bile duct ligated rats. Fifty-six animals were included in each of the following 7 groups: control, SPC control, phosphate-buffered solution control, sham operated, bile duct ligation (BDL), BDL plus phosphate-buffered solution, and BDL plus SPC. Sphingosylphosphorylcholine was administered 14 days at a daily dose of 2 microm/mL intraperitoneally. The severity of cholestasis and hepatic injury was determined by changes in the plasma enzyme activities of aspartate aminotransferase, alanine aminotransferase, gama glutamin transferase, and levels of total bilirubin and direct bilirubin. Malondialdehyde, nitric oxide, and superoxide dismutase were determined to evaluate the oxidative status in the liver tissue. Myeloperoxidase activity and levels of tissue hydroxyproline were determined to assess neutrophil activation and collagen accumulation, respectively. Treatment with SPC markedly reduced serum transaminase activities as compared to BDL rats. Sphingosylphosphorylcholine also inhibited the increase in liver malondialdehyde; nitric oxide levels significantly and also attenuated the depletion of superoxide dismutase in the liver after BDL. Similarly, the increase in tissue myeloperoxidase activity and hydroxyproline owing to BDL was also attenuated by the SPC treatment. These data were supported by histopathologic findings. The alpha-smooth muscle actin-positive cells in the BDL were observed to be reduced with the SPC treatment. In conclusion, these findings suggested that SPC can attenuate hepatic damage in extrahepatic cholestasis by prevention of oxidative stress, and inflammatory process. All these findings suggest that SPC may be a promising new therapeutic agent for cholestatic liver injury.

Soluble Lectin-Like Oxidized LDL Receptor 1 as a Possible Mediator of Endothelial Dysfunction in Patients With Metabolic Syndrome

Metabolic syndrome (MetS) defines a well‐known cluster of metabolic disturbances associated with an increased risk of cardiovascular disease and diabetes. The aim of this study was to examine the distribution of soluble lectin‐like oxidized low‐density lipoprotein (LDL) receptor‐1 (sLOX‐1) levels in patients with MetS, possible association of sLOX‐1 with oxidized LDL (oxLDL), endothelial nitric oxide synthase (eNOS), nitric oxide (NOx), endothelin‐1 (ET‐1), paraoxonase 1 (PON1), and arylesterase (ARE) activities, and these parameters compared with healthy controls.

Comparison of adiponectin values in obese and nonobese diabetics and relationship with metabolic parameters

Gerec ve Yontem: Calismaya hastanemiz diyabet ve endokrinoloji polikliniklerine basvuran 46 obez, 38 obez olmayan hasta alindi. Antropometrik ve metabolik degiskenleri adiponektin duzeyleri ile karsilastirildi. Hastalarin aclik kan sekeri, tokluk kan sekeri, ure, kreatinin, toplam protein, albumin, toplam kolesterol, LDL-kolesterol, HDL-kolesterol, trigliserid, HbA1c degerleri spektrofotometrik yontemle olculdu. Insulin duzeyleri elektrokemiluminesans, adiponektin ise sandvic-ELISA yontemi ile olculdu.