Bolkan Simsek

PLASMA MALONDIALDEHYDE (MDA) LEVELS IN BREAST AND LUNG CANCER PATIENTS

Objective: To measure the levels of malondialdehyde (MDA), a marker of lipid peroxidation, in patients with breast and lung cancer.

Oxidative status in rheumatoid arthritis

The insufficiency of antioxidant defense systems and the acceleration of the oxidative reactions can be results of the pro-oxidant/antioxidant imbalance in rheumatoid arthritis (RA). The aim of our study was to investigate the changes in oxidant status by measuring two different parameters; one was the level of malondialdehyde (MDA) as an index of lipid peroxidation and the other was total oxidative status; we could then compare our results with the antioxidant status, superoxide dismutase (SOD) enyzme activities. All were assessed in 22 patients with active RA and 18 age- and gender-matched control subjects. While serum MDA levels were significantly increased in patients with RA compared to the control group (p<0.03), the total oxidative status levels were decreased in patients with RA compared to the control group (p<0.008), and serum SOD activities did not show any statistical difference between the two groups. In conclusion, the increased MDA levels in our study may be important as a marker but are not sufficient to conclude that there was an increase in oxidative stress in RA patients because supporting results were not obtained from SOD and oxidative status measurements. These results give further support to the concept of oxygen free radicals playing a role in the pathogenesis of chronic inflammatory disorders, but we also consider that there is a more complex relationship than has been assumed. We think that further studies are needed to clarify these conflicting results.

Serum β–carotene, vitamin E, vitamin C and malondialdehyde levels in several types of cancer

We measured the levels of serum carotenoids (β–carotene), total tocopherol (vitamin E), ascorbic acid and malondialdehyde (MDA) in newly diagnosed cancer cases. Levels of the antioxidants and MDA in serum samples from 208 subjects with cancer affecting different sites (59 breast, 38 head and neck, 46 genitourinary, 12 lung, 20 gastrointestinal and 33 other sites) were compared with levels in 156 controls. Cases and controls were compared with respect to a number of potentially confounding factors: age, sex, smoking status, Quetelet index (kg/m2), diet and alcohol intake. Mean (±SD) levels of β–carotene, vitamin E and vitamin C were significantly lower among the cases than the controls (49 35±36 55 μg/1, 0 60±014 mg/dl, 0 40±0 27 mg/dl and 75 31±28 59 mg/dl, 0 98±0 13 mg/dl, 0 88±0 47 mg/dl, respectively) (P < 0 05).

Serum uric acid levels in cardiovascular diseases

Objective: Comparison of the serum uric acid levels of healthy people ( n=71) and patients with cardiovascular diseases (CVD) (n=62). Subjects and methods: The patients included had either experienced acute myocardial infarction (AMI) ( n=31), atherosclerosis (AT) (n=23) or ischaemia ( n=8). The mean values (x±SD) of serum uric acid levels of the control group, the patients with CVD as a whole, and patients with AMI, AT and ischaemia were 4·15±0·45 mg%, 5·6±2·06 mg%, 5·96±2·60 mg%, 5·38±1·22 mg% and 4·94±1·40 mg%, respectively. A statistically higher level of serum uric acid was found in the controls compared to the CVD patients ( P < 0·05). Conclusion: The higher serum uric acid levels found in CVD patients suggests that any protective antioxidant effect which uric acid has is overwhelmed by other negative effects on pathogenesis.

Increased levels of 8-hydroxydeoxyguanosine and its relationship with lipid peroxidation and antioxidant vitamins in lung cancer

Abstract Background: Reactive oxygen species produced either endogenously or exogenously can attack lipids, proteins and DNA in human cells and cause potentially deleterious consequences. In recent years, their role in the pathogenesis of lung cancer and the preventive effect of antioxidants have been studied extensively. In this study, our aim was to investigate the levels of 8-hydroxy-2′-deoxyguanosine (8OHdG) and malondialdehyde as a marker for the effects of reactive oxygen species on DNA and lipids, the levels of antioxidant vitamins and the correlations between these oxidative stress markers and antioxidants in lung cancer. Methods: Serum malondialdehyde, β-carotene, retinol, and vitamins C and E were measured by high-performance liquid chromatography methods in fasting blood samples and 8OHdG was measured by gas chromatography-mass spectrometry in 24-h urine samples of patients with lung cancer (n=39) and healthy controls (n=31). Results: The levels of 8OHdG and malondialdehyde were significantly higher (p<0.05 and p<0.005, respectively) and β-carotene, retinol, and vitamins C and E (p<0.0001, p<0.0001, p<0.0001, and p<0.05, respectively) were significantly lower in patients than in controls. There was a significantly positive correlation between 8OHdG and malondialdehyde (r=0.463, p=0.01) and a negative correlation between the levels of 8OHdG and retinol (r=–0.419, p=0.021) in the patient group. Conclusions: Our results demonstrate that the oxidant/antioxidant balance was spoiled in favor of lipid peroxidation and DNA damage in lung cancer patients. Significant increases in the levels of malondialdehyde and 8OHdG and decreases in the levels of antioxidants suggest the possible involvement of oxidative stress in lung cancer. Clin Chem Lab Med 2008;46:107–12.

Influence of Gender on C-Reactive Protein, Fibrinogen, and Erythrocyte Sedimentation Rate in Obstructive Sleep Apnea

Inflammation is one of the pathophysiological pathways suggested for the development of cardiovascular disease in obstructive sleep apnea (OSA). The recurrent nocturnal episodes of hypoxia/reoxygenation observed in patients with OSA appear to be partly responsible for the systemic inflammatory response. The aim of this study was to investigate the role of inflammation by measuring the C-reactive protein (CRP) and fibrinogen levels, and erythrocyte sedimentation rate (ESR) in the OSA according to gender. This study included 139 apparently healthy subjects with newly diagnosed OSA and 27 control subjects who underwent overnight polysomnography and routine blood tests. Levels of inflammatory markers (CRP, fibrinogen, and ESR) were determined from the blood samples taken in the morning. The levels of CRP and fibrinogen were significantly higher in patients than in controls (p<0.0001 and p=0.001, respectively). Fibrinogen and ESR were significantly higher in the female patients than in the male patients (p<0.0001). In female patients, CRP and ESR correlated with time spent at oxygen saturation (T%SaO2)<90 (R=0.327, p=0.029 and R=0.301, p=0.05, respectively), T%SaO2<85 (R=0.482, p=0.001 and R=0.409, p=0.006, respectively), oxygen desaturation index (ODI) (R=0.298, p=0.047 and R=0.340, p=0.026, respectively), lowest oxygen saturation (SaO2) (R=-0.293, p=0.051 and R=-0.374, p=0.013, respectively), mean SaO2 (R=-0.408, p=0.005 and R=-0.385, p=0.011, respectively). In male patients, CRP correlated with T%SaO2<90 (R=0.267, p=0.009), T%SaO2<85 (R=0.279, p=0.006), mean SaO2 (R=-0.284, p=0.006) and fibrinogen correlated with T%SaO2<90 (R=0.282, p=0.028), and mean SaO2 (R=-0.252, p=0.05). In conclusion, increased values of systemic inflammatory markers and their correlations with sleep data observed in our study support other studies suggesting the possible involvement of inflammation in OSA. As this correlation is more apparent in female patients then the males, it suggests that there may be a stronger relation between OSA development and inflammation in females. Higher levels of CRP, fibrinogen, and ESR may result from the combined interactions of obesity, metabolic syndrome (MetS) and nocturnal hypoxia.

Tryptophan degradation and neopterin levels in treated rheumatoid arthritis patients

Increased kynurenine/tryptophan—reflects trytophan degradation—and neopterin levels have been regarded as a biochemical marker of cell-mediated immune response and inflammation. This study was designed to evaluate the usefulness of tryptophan degradation and neopterin levels in active rheumatoid arthritis patients under therapy. In this case–control study, kynurenine and tryptophan levels were determined by HPLC; neopterin and tumor necrosis factor-α levels were measured with ELISA in 32 active rheumatoid arthritis patients and 20 healthy controls. Although mean values of tryptophan, kynurenine, ratio of kynurenine to tryptophan, neopterin, and tumor necrosis factor-α levels did not show statistically significant differences between patient and control groups, neopterin levels correlated positively with kynurenine (r = 0.582, p < 0.02), kynurenine/tryptophan (r = 0.486, p < 0.05), erythrocyte sedimentation rate (r = 0.472, p < 0.05) and RF (r = 0.478, p < 0.05) in the rheumatoid arthritis group. CRP levels of the patient group correlated with kynurenine levels (r = 0.524, p < 0.03). Determination of tryptophan degradation and neopterin levels in chronic inflammatory disease may provide a better understanding of progression of the disease.

Free radical reaction products and antioxidant capacity in beating heart coronary artery surgery compared to conventional bypass

Oxygen-derived free radicals are important agents of tissue injury during ischemia and reperfusion. The aim of this study was to investigate changes in protein and lipid oxidation and antioxidant status in beating heart coronary artery surgery and conventional bypass and to compare oxidative stress parameters between the two bypass methods. Serum lipid hydroperoxide, nitric oxide, protein carbonyl, nitrotyrosine, vitamin E, and β-carotene levels and total antioxidant capacity were measured in blood of 30 patients undergoing beating heart coronary artery surgery (OPCAB, off-pump coronary artery bypass grafting) and 12 patients undergoing conventional bypass (CABG, on-pump coronary artery bypass grafting). In the OPCAB group, nitric oxide and nitrotyrosine levels decreased after reperfusion. Similarly, β-carotene level and total antioxidant capacity also decreased after anesthesia and reperfusion. In the CABG group, nitric oxide and nitrotyrosine levels decreased after ischemia and reperfusion. However, protein carbonyl levels elevated after ischemia and reperfusion. Vitamin E, β-carotene, and total antioxidant capacity decreased after ischemia and reperfusion. Significantly decreased nitration and impaired antioxidant status were seen after reperfusion in both groups. Moreover, elevated protein carbonyls were found in the CABG group. The off-pump procedure is associated with lower degree of oxidative stress than on-pump coronary surgery.

Increased plasma homocysteine and allantoin levels in coronary artery disease: possible link between homocysteine and uric acid oxidation.

Objective — Homocysteine increases the damage to the cardiovascular system in different ways, one of them is the formation of reactive oxygen species resulting from the auto-oxidation of homocysteine. At the same time, uric acid is one of the major antioxidants in the plasma and protects the cells towards increased ROS activity. In humans, allantoin is only formed from non-enzymatic oxidation of uric acid by free radicals.We aimed to determine the levels of homocysteine, uric acid and allontoin in patients with coronary artery diseases, and to evaluate the possible correlation between homocysteine and allantoin. Methods and results — Plasma total homocysteine, uric acid and allantoin levels of 50 patients with coronary artery diseases and 23 healthy controls were determined by HPLC methods. Commercial diagnostic kits were used for the determination of other biochemical parameters.We obtained higher homocysteine, uric acid and allantoin levels in patients than in controls (p<0.0001). Homocysteine levels were positively correlated with uric acid (r=0.435, p<0.0001) and allantoin (r=0.583, p<0.0001) levels in the whole study population.This correlation was persistent between allantoin and homocysteine after adjustment of these parameters for age, sex and creatinine.We accepted 15.0 mol/l as a cut-off value between normal and mildly elevated homocysteine levels for patients and controls. Twenty-five patients showed moderate hyperhomocysteinaemia. The mean allantoin and uric acid values of the moderate hyperhomocysteinaemic group were significantly higher than that of the group having lower homocysteine levels than this cut-off value (p<0.0001 for allantoin, p<0.02 for uric acid). Conclusion — Results imply that there is increased allantoin production resulting from uric acid oxidation by free radicals in hyperhomocysteinaemic patients with coronary artery disease. The possible significance of the relationship between homocysteine and allantoin warrants further study.

The effect of 1-month thyme using in elite sportsmen on oxidant stress and anti-oxidant capacity

The object of the study is to determine the effect of thyme loading during exercise at elite wrestlers on oxidant stress and anti-oxidant capacity. Totally 18 elite wrestlers were involved in the study. The wrestlers were randomly divided into two groups, experimental and placebo. The subjects were loaded 1 g dried thyme tea three times a day after meals during 35-day period. The blood samples were taken before and after loading thyme, and total antioxidant capacity (TAC), melondialdehyde (MDA) and total sulphydryl group (RSH) were analysed. To evaluate the dates, Wilcoxon signed rank test was used for in-group evaluation and Mann–Whitney U test was used for inter group evaluation and significance level α was set at 0.05. While there were no differences between groups before loading thyme, TAC values were found meaningfully increased after loading in experimental group (p<0.05). However, the decrease in MDA values of the experimental group after loading thyme was statistically significant (p<0.01). The decreases in RSH values of the experimental group were insignificant (p>0.05). In the other hand experimental group decreasing of the MDA values and increasing of the TAC values were found statically significant compared with placebo groups (p<0.05). But compared with two groups RSH values were statically insignificant. It was concluded that thyme loading increases enzymatic antioxidant capacity but does not have any effects on non-enzymatic antioxidant structures during exercise. However, thyme loading reduced oxidant stress in elite sportsmen.