SIRT6 expression and oxidative DNA damage in individuals with prediabetes and type 2 diabetes mellitus.

Sirtuins (SIRTs) is a family of NAD+ dependent histone deacetylases. SIRT6 takes play in glucose homeostasis, genomic stability and DNA repair. Although increased oxidative DNA damage and decreased DNA repair activity were determined in diabetes mellitus, the possible relation between level of oxidative DNA damage and SIRT6 expression has not been investigated so far. We determined SIRT6 expression and urinary 8-hydroxy deoxyguanosine (8-OHdG) levels, marker of oxidative DNA damage, in cases with prediabetes (PreDM) and type 2 diabetes mellitus (T2DM). SIRT6 gene expression was determined in peripheral blood leukocytes of 70 patients with type 2 diabetes, 50 cases in prediabetic stage and 40 healthy subjects. SIRT6 mRNA levels were determined by quantitive real time- polymerase chain reaction. SIRT6 protein was detected by immunocytochemical staining. Urinary 8-hydroxy deoxyguanosine (8-OHdG) levels were measured by ELISA. There was no significant difference between groups for SIRT6 mRNA level. SIRT6 immunopositivity in T2DM group was lower when compared to those in preDM group (P<0.05). SIRT6 positive cell number in T2DM and preDM groups were lower in comparison to control group (P<0.01 for both), however, when study groups were subdivided into two groups according to their age, the difference between preDM and control groups disappeared in both mid-aged and old-aged groups. The urinary 8-OHdG level was found to be higher in the T2DM group in comparison to preDM group (P<0.05). When age is taken into consideration, urinary 8-OHdG level in the T2DM group was found to be higher than those in both preDM and control groups in the old-aged cases but no significant difference was determined between groups in the mid-aged cases. There was no relation between SIRT6 expression and urinary 8-OHDG excretion. It was concluded that SIRT6 may take play in development of T2DM but this effect seems to be independent from repair of oxidative DNA damage.

Significance of serum c-erbB-2 oncoprotein, insulin-like growth factor-1 and vascular endothelial growth factor levels in ovarian cancer.

OBJECTIVES: Our aim was to determine the predictive values of serum levels of several growth factors in ovarian cancer, including soluble c-erbB-2 oncoprotein, insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF). BACKGROUND: Previous studies have shown that growth factors play an important role in carcinogenesis. METHODS: Two groups were established. One of them was the malignant group which included 41 patients with ovarian carcinoma and the other was the control group that was made up of 28 healthy volunteers. Preoperative serum samples were obtained from the patients, and c-erbB-2, IGF-1 and VEGF levels were measured in these samples using ELISA. Serum CA-125 levels were also determined, by chemiluminescent microparticle immunoassay. RESULTS: VEGF levels of the malignant group were significantly higher than those of the control group (p < 0.01). CA-125 levels were also significantly higher than the in control group (p < 0.001). Area under the ROC curve (AUC) was 0.982 for CA-125, 0.780 for VEGF, 0.603 for c-erbB-2, and 0.467 for IGF-1 in differentiating cancers from controls. CONCLUSION: Serum VEGF levels might be a predictor for diagnosis in ovarian cancer patients, while serum c-erbB-2 and IGF-1 levels do not have a clinical significance in terms of ovarian cancer (Tab. 1, Fig. 1, Ref. 46).

DNA damage in children with scoliosis following X-ray exposure.

AIM: It has been suggested that cancer incidence is high in subjects with scoliosis who are relatively more often exposed to X-ray for diagnosis and follow-up. X-ray is a kind of ionizing radiation and leads to formation of oxygen free radicals which are capable of damage to DNA, thus altered gen expression and mutation. p53 tumor suppressor gene plays a crucial role in the damage response. It controls the checkpoint of cell cycle and redirects the cell metabolism to either repair of damaged DNA or apoptosis as response to DNA damage. The aim of the present study was to examine serum levels of 8-Hydroxydeoxyguanosine (8-OHdG), a strongly mutagenic product of oxidative DNA damage, p53, superoxide dismutase (SOD) and glutathione peroxidase (G-Px), as antioxidant activity, in children with scoliosis who had got whole spine radiograph two times during the last year. METHODS: A total of 31 children with adolescent idiopathic scoliosis and 21 age-matched healthy children were included in the study. Serum levels of 8-OHdG and p53 were measured with ELISA kits. SOD and G-Px activities were determined with spectrophotometric assays. RESULTS: Serum levels of 8-OHdG and p53 were found to be higher (P<0.001 and P<0.01, respectively), SOD activity was found to be lower (P<0.001) in the children with scoliosis as compared to age-matched controls. There was no significant difference between the groups for G-Px activity. CONCLUSION: Our data show that X-ray exposure causes increased 8-OHdG level, and decreased SOD activity, which both may reflect a tumor promoting condition. Increased p53 level may be interpreted as a compensatory effort of cell to X-ray mediated DNA damage.

DNA damage in children with scoliosis following X-ray exposure.

AIM: It has been suggested that cancer incidence is high in subjects with scoliosis who are relatively more often exposed to X--ray for diagnosis and follow--up. X--ray is a kind of ionizing radiation and leads to formation of oxygen free radicals which are capable of damage to DNA, thus altered gen expression and mutation. p53 tumor suppressor gene plays a crucial role in the damage response. It controls the checkpoint of cell cycle and redirects the cell metabolism to either repair of damaged DNA or apoptosis as response to DNA damage. The aim of the present study was to examine serum levels of 8--Hydroxydeoxyguanosine (8--OHdG), a strongly mutagenic product of oxidative DNA damage, p53, superoxide dismutase (SOD) and glutathione peroxidase (G--Px), as antioxidant activity, in children with scoliosis who had got whole spine radiograph two times during the last year. METHODS: A total of 31 children with adolescent idiopathic scoliosis and age--matched 21 healthy children were included in the study. Serum levels of 8--OHdG and p53 were measured with ELISA kits. SOD and G--Px activities were determined with spectrophotometric assays. RESULTS: Serum levels of 8--OHdG and p53 were found to be higher (P<0.001 and P<0.01, respectively), SOD activity was found to be lower (P<0.001) in the children with scoliosis as compared to age--matched controls. There was no significant difference between the groups for G--Px activity. CONCLUSION: Our data show that X--ray exposure causes increased 8--OHdG level, and decreased SOD activity, which both may reflect a tumor promoting condition. Increased p53 level may be interpreted as a compensatory effort of cell to X--ray mediated DNA damage.

Serum levels of fetuin A and 8-hydroxydeoxyguanosine in morbidly obese subjects.

Insulin resistance is one of the feature of obesity. Fetuin A is inhibitor of insulin receptor which belongs the family of receptor tyrosine kinase. It has been observed that fetuin-null mice are resistant to diet-induced obesity and they exhibit increased insulin sensitivity. Increased production of reactive oxygen species is suggested to be associated with insulin resistance. Attacks of reactive oxygen species to DNA results in base oxidation. Among the oxidized bases, 8-hydroxydeoxyguanosine is predominant lesion with pro-mutagenic potential. In the present study; measurement of serum levels of fetuin A and 8-hydroxydeoxyguanosine in obese subjects (n=46) and healthy controls (n=22), and examination of the relations between these parameters and insulin resistance have been purposed. Blood samples were taken form morbidly obese subjects after a 12 h fasting. Serum levels of fetuin A and 8-hydroxydeoxyguanosine were measured by ELISA. Statistical analysis was performed by Mann Whitney U test and correlations were examined by Spearman correlation coefficient. Serum levels of total cholesterol, HDL, LDL, VLDL, triglycerides, free T3, free T4, fasting glucose, c-peptide and %HbA1c in the obese group were found to be different from those in the control group. Serum level of fetuin A was found to be higher, 8-hydroxydeoxyguanosine level was found to be lower in the morbid obese group than those in the control group. Fetuin A was found to be positively correlated with HOMA-IR (r:0,40, P<0.05) and negatively correlated with 8-hydroxydeoxyguanosine (r:-0,52, P<0.01). No significant association was determined between body mass index and measured parameters. In conclusion, serum level of fetuin A is high in morbidly obese subjects and is negatively associated with 8-hydroxydeoxyguanosine level in peripheral circulation. Fetuin A may be a promising link between insulin resistance and obesity as well its comorbidities.

Factors affecting morbidity in chronic tuberculous empyema.

BACKGROUND: Chronic empyema is not a rare complication of pulmonary tuberculosis. Various treatment modalities ranging from open drainage to pneumonectomy, depending on the status of the disease, have been used to treat this complication. However, the best strategy for this disease remains unknown. This study examined the results of different treatment strategies for chronic tuberculous empyema. METHODS: Between January 1993 and December 2002, 36 patients (29 male and 7 female) with an average age of 29.3 years (range 13 - 52 years) presented with chronic tuberculous empyema characterized by empyema cavity and persistent pleural infections that were secondary to tuberculosis. The series consisted of patients who had had tube thoracostomy and underwater drainage without complete re-expansion. All patients were treated with open drainage. Of these, 6 patients had Eloesser flap for complete drainage of pleural pus and resolution of pleural infection. RESULTS: Eloesser-flap drainage resulted in a higher morbidity compared to the open-drainage-only method ( P = 0.011). Pneumonectomy, used as a final therapeutic option, resulted in more complications postoperatively ( P = 0.034). Antituberculosis therapy lasting six months or longer reduced the morbidity rate (54 % vs. 33.3 %), but the difference was not significant. CONCLUSIONS: Our findings indicate that open drainage leads to better results compared to those of Eloesser flap in patients with chronic tuberculous empyema. Patients who underwent pneumonectomy were expected to have higher complication rates and the procedure must therefore be avoided when possible.

Prognostic significances of oxidative DNA damage evaluated by 8-hydroxy-deoxyguanosine and antioxidant enzymes in patients undergoing resection of gastric and colon carcinoma.

Oxidant/antioxidant balance has been suggested as an important factor for initiation and progression of cancer. In order to determine whether the degree of oxidative DNA damage and antioxidant enzyme activities in plasma obtained from patients with gastric and colon cancer who undergo resection can be used as a useful prognostic predictor, plasma level of 8-hydroxydeoxyguanosine (8-OHdG), activities of glutathione peroxidase (G-Px) and superoxide dismutase (SOD) were examined. 19 patients with gastric cancer and 26 patients with colon cancer who were undergoing resection of tumor were included by the study. Venous blood samples were taken just before the surgery. Plasma level of 8-OHdG was determined with ELISA, SOD and G-Px activities in plasma were measured by spectrophotometric kits. 8-OHdG level and activity of G-Px were found to be decreased, SOD activity was found to be increased in both gastric and colon cancer groups as compared to control group. Alpha fetoprotein was found to be correlated with G-Px in the gastric cancer group and correlated with 8-OHdG in the colon cancer group. SOD activity was correlated with CA-15-3 in the gastric cancer group. Low plasma level of 8-OHdG and altered antioxidant activity may implicate the deficient repair of oxidative DNA damage in patients with gastric and colon cancer. Those measured parameters were not found to be related with histopathological data but correlated with some tumor markers.

Effect of sex hormones on lipid peroxidation in women with polycystic ovary syndrome, healthy women, and men.

Recently, the influence of free radicals and lipid peroxides on many diseases, the effect of sex hormones on lipid peroxidation and antioxidant effects of estrogens have received considerable interest. In the present study we aimed to investigate the relationship between sex hormones and both lipid peroxidation and glutathione content in women with polycystic ovary syndrome (POS), in healthy women and in healthy men. We measured levels of lipid peroxides and sex hormones in plasma and levels of glutathione in erythrocytes of all cases. We evaluated the level of thiobarbituric acid reactive substances (TBARS) as an index of lipid peroxides and erythrocyte glutathione level as an index of antioxidant. We found that plasma levels of free testosterone, dehydroepiandrosterone sulfate (DHEAS) and estradiol significantly higher in the women with POS group than in the healthy women group. There was no significant difference in the levels of both plasma TBARS and erythrocyte glutathione, between women with POS group and healthy women group. Plasma DHEAS levels of healthy men and women with POS were similar. Plasma TBARS level was higher and erythrocyte glutathione level was lower in the healthy men group than in both the healthy women group and in the women with POS group. These data imply that testosterone has an oxidant effect. DHEAS which is an antioxidant, has a protective role in females with POS. Estrogens have an antioxidant effect but this action changes according to its dominant degradation pathway.

Effects of hormone replacement therapy on lipid peroxides and oxidation system in postmenopausal women.

A short-term evaluation of 6 months of estrogen therapy on oxidant status in 38 postmenopausal women was conducted. The levels of serum lipid peroxidation products, glutathione (GSH) status, and glutathione-related enzymes were evaluated before and after 6 months of hormone replacement therapy. After 6 months of estrogen treatment there was a significantly increased concentration of thiobarbituric acid-reactive substances (TBARS), which are an end product of lipid peroxidation. This was accompanied by a significant increase in the activity of glutathione peroxidase (GSH-Px). However, the activities of glutathione reductase (GSSG-R) and superoxide dismutase (SOD) were significantly decreased and total protein thiols were reduced. Data suggest that hormone replacement therapy in postmenopausal women is associated with oxidant mechanisms.

The susceptibility of red blood cells to autoxidation in type 2 diabetic patients with angiopathy.

We examined the in vitro susceptibility of red blood cell (RBC) lipids to oxidation in type 2 diabetic patients with or without angiopathy. Lipid peroxidation was assessed by quantifying thiobarbituric acid (TBA) reactivity as malondialdehyde (MDA). We also examined the RBC antioxidant status by determining glutathione (GSH) levels. Before in vitro oxidation, RBC MDA levels were significantly higher in both diabetic groups than in the controls (P < .001), and a significant difference was found between the two diabetic groups (P < .05). After in vitro treatment of RBCs with hydrogen peroxide, the degree of lipid peroxidative damage was significantly higher in diabetic patients with angiopathy versus diabetics without angiopathy (P < .001). Diabetic patients have low RBC GSH levels compared with controls, and after in vitro oxidation, the levels were significantly decreased in diabetics (P < .001). There was not a significant correlation between RBC MDA levels and glycated hemoglobin (GHb), plasma cholesterol, and triglyceride. The correlation between RBC MDA and GSH was weak (P < .001). We suggest that the results of this study might help to clarify the role of oxidative mechanisms as an in vitro model of degenerative damage in type 2 diabetic angiopathic complications.

Urinary glycosaminoglycan excretion in urolithiasis.

Urinary glycosaminoglycan (GAG) excretion was measured in children with idiopathic urolithiasis (15 girls and 10 boys; mean (SD) age 6.2 (2.4) years) and in healthy controls (10 girls and 14 boys; mean (SD) age 6.8 (3.8) years). GAG excretion was expressed as a GAG/creatinine (mg/g) ratio and was evaluated using dimethylmethylene blue. In healthy control children, the mean (SD) GAG/creatinine ratio was 31.67 (12.76) and it was similar in girls and boys. The children with idiopathic urolithiasis had significantly lower mean (SD) GAG/creatinine ratios than controls (22.59 (7.35)). Therefore, urinary GAG excretion may be important in the disease process in children with urolithiasis, as it is in adults.

Erythrocyte susceptibility to lipid peroxidation in patients with coronary atherosclerosis.

In recent years it has been reported that free oxygen radicals play an important role in the pathogenesis of degenerative diseases and that antioxidant vitamins such as vitamins E or C prevent their harmful effects. In this study, we evaluated the following: Erythrocyte susceptibility to lipid peroxidation; the role of erythrocyte glutathione (GSH) as an antioxidant; plasma lipid fractions; and the relationship between plasma lipid peroxides and antioxidant vitamin levels. Thiobarbituric acid-reactive substance (TBARS) levels were measured to determine the levels of plasma lipid peroxides and the susceptibility to lipid peroxidation when erythrocytes were stressed by hydrogen peroxide for 2 h in vitro. Erythrocyte TBARS production was significantly higher in patients with coronary atherosclerosis than in the controls. On the other hand, the levels of plasma high-density lipoproteins, vitamin C, vitamin E and erythrocyte GSH were significantly lower, and the levels of plasma total cholesterol, triglycerides, low-density lipoproteins and TBARS were significantly higher in the patients with coronary atherosclerosis than in the controls. In conclusion, our results indicate that erythrocytes from patients with coronary atherosclerosis are more susceptible to oxidation than those of controls and that these patients have lowered antioxidant capacity as revealed by decreased plasma levels of vitamins C and E.