Ömer Akyol

Antioxidant enzyme activities and oxidative stress in affective disorders

Recent data from several reports indicate that free radicals are involved in the biochemical mechanisms underlying neuropsychiatric disorders in human. The results of several reports suggest that lower antioxidant defences against lipid peroxidation exist in patients with depression and that there is a therapeutic benefit from antioxidant supplementation in unstable manic-depressive patients. We investigated the antioxidant enzyme status and the indices of oxidative stress and lipid peroxidation end products in erythrocytes from patients with affective disorder. For this purpose, we measured superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activities, as well as malondialdehyde (MDA) and nitric oxide (NO) levels in patients with affective disorders (n=30) in both pre- and post-treatment periods, and in a control group (n=21). CAT activities were significantly decreased in both pre-, and post-treatment periods in patients compared to the control group. GSH-Px activity in the pre-treatment period in the patients was significantly lower than both post-treatment patient and control groups. MDA levels were increased in both pre-, and post-treatment patient groups compared to the control group. NO level was lower in the pre-treatment patient group than in the control group. There were statistically significant correlations between SOD and MDA, and SOD and NO in the pre-treatment patient and control groups. Because the overall study sample was small, and the post-treatment patient group was even smaller, it can tentatively be suggested that the antioxidant system is impaired during a mood episode in patients with affective disorders, normalizing at the end of the episode.

Effect of Smoking on Serum Concentrations of Total Homocysteine, Folate, Vitamin B12, and Nitric Oxide in Pregnancy: A Preliminary Study

Objective: Nitric oxide (NO) is a potent vasodilator released by endothelial cells that plays an important role in modulating maternal and fetal vascular tone in normal pregnancy. Lower plasma levels of vitamins may result in hyperhomocysteinemia, a known risk factor in pregnancy. The aim of this study was to investigate whether there are alterations in the serum levels of total homocysteine (tHcy), folate, vitamin B12, and total nitrite, as an index of NO, in smoking as compared with age-matched nonsmoking pregnant women. Methods: Thirty-three women (19 smoking and 14 nonsmoking) between 16 and 22 weeks of their gestation were included in this study. The serum tHcy levels were analyzed by using an enzyme-linked immunosorbent assay kit. Vitamin B12 and folate values were measured by means of DPC kits. Total nitrite was measured by Griess reaction as an index of endogenous NO production. Results: The serum tHcy concentrations were significantly increased in smoking as compared with nonsmoking pregnant women (p < 0.001). The folate and vitamin B12 concentrations were lower in smoking than in nonsmoking pregnant women, but only the differences in folate concentrations were statistically significant (p < 0.001). The tHcy concentrations showed a significant negative correlation with folate in the smoking pregnant women. The serum total nitrite concentrations were lower in smoking than in nonsmoking pregnant women (p < 0.05). In addition, the serum nitrite levels in smoking pregnant women had significant negative correlations with tHcy and positive correlations with folate and vitamin B12 levels. Conclusions: In the light of our findings, we propose that smoking might enhance the vasoconstrictor capacity in pregnant women by increased tHcy concentrations and by a simultaneous decrease in the production of NO which is a vasodilator compound.

The relationships between plasma and erythrocyte antioxidant enzymes and lipid peroxidation in patients with rheumatoid arthritis

Objective. The present study was undertaken to evaluate the activities of some key erythrocyte and plasma enzymes participating in free radical metabolism and the end product of lipid peroxidation in rheumatoid arthritis, and whether there are any differences for these parameters between newly diagnosed untreated patients and rheumatoid arthritis patients on drug therapy. Patients and methods. Superoxide dismutase and catalase activities, and malondialdehyde levels were determined in erythrocytes and plasma samples from 54 patients with rheumatoid arthritis (21 of whom without any treatment and 33 on classical therapy regimens) and from 33 healthy controls. Results. There were no statistically significant differences in mean values of activities of the erythrocyte enzymes between the patients and controls. Malondialdehyde levels were significantly increased in both newly diagnosed untreated patients and patients on drug therapy compared to control subjects. Malondialdehyde levels were lower in the treated group than the newly diagnosed untreated group (0.214 ± 0.111 μmol/L and 0.388 ± 0.075 μmol/L, respectively) (P < 0.0001). Mean plasma superoxide dismutase activity was lower in the group of newly diagnosed untreated patients compared to those of the treated and control groups (1.31 ± 0.69 U/mL, 1.79 ± 0.94 U/mL and 2.48 ± 0.95 U/mL, respectively) (P < 0.0001, untreated vs control groups). Conclusions. These results suggest sufficient antioxidant enzyme activities in erythrocytes in patients with rheumatoid arthritis and also increased lipid peroxidation end products in newly diagnosed untreated patients compared to control group and patients on drug therapy.

Antioxidant enzyme activities and lipid peroxidation products in heart tissue of subacute and subchronic formaldehyde-exposed rats: a preliminary study.

Objective: The aim of this experimental study was to evaluate the oxidant/antioxidant status and lipid peroxidation in the heart of rats exposed to formaldehyde (FA) inhalation for four weeks (subacute) or 13 weeks (subchronic) continuously. Methods and results: Sixty Wistar albino rats were divided into six groups randomly (ten in each group). The first and second groups were used as subacute and subchronic control groups. FA gas was generated from paraformaldehyde and pumped to a closed glass chamber. Rats were exposed to atmosphere containing 10 and 20 ppm FA (8 h/day, five days per week) during a four and 13 weeks period. After heart tissues were obtained and homogenized, thiobarbituric acid-reactant substances (TBARS) and nitric oxide (NO) levels, as well as superoxide dismutase (SOD) and catalase (CAT) activities, were measured. There were statistically significant findings in SOD and CAT activities in the study groups compared to the control group. Heart tissue SOD level was increased in the group exposed to subacute 10 and 20 ppm FA inhalation compared to the control group (P≤0.011 and ≤0.0001). In addition, heart tissue SOD level was increased in the group exposed to subchronic 10 and 20 ppm FA inhalation compared to the corresponding control group (P≤0.001). On the other hand, there were statistically significant decreases in CAT activity in subacute 10 and 20 ppm groups compared to the corresponding control group (P≤0.012 and ≤0.039, respectively). Although not significant, TBARS levels were increased in both subacute 10 ppm (P=0.100) and subchronic 20 ppm (P=0.053) groups compared to their corresponding control groups. Tissue NO levels were unchanged upon FA inhalation. In the correlation analyses, a meaningful relationship between SOD and CAT activities in subchronic 10 ppm group (r=-0.685, P≤0.029); SOD activity and TBARS level in subchronic 20 ppm group (r=-0.675, P≤0.032); and CAT activity and NO level in subchronic 20 ppm group (r=-0.810, P≤0.005) were found. Conclusion: From the findings of our study, it can be interpreted that subacute and subchronic FA inhalation may stimulate oxidative stress and thus, some secondary toxic effects in cardiac cells and tissue. This increase in the oxidative stress could not induce lipid peroxidation in the membranous structure of cardiac cells. An increased SOD enzyme activity was thought to be secondary to decreased CAT activity, as a compensation mechanism, preventing heart tissue from destruction induced by FA.

Serum adenosine deaminase and total superoxide dismutase activities before and after surgical removal of cancerous laryngeal tissue

In this study, pre- and post-operative serum activities of adenosine deaminase (ADA) and total superoxide dismutase (SOD) enzymes were measured in patients with squamous cell laryngeal cancer. Activities of both enzymes were found to be higher in cancerous patients compared to the controls. No significant differences were found however between pre- and post-operative values for both enzymes in the patient group. It has been suggested that ADA and SOD enzymes leak from the cancerous laryngeal tissues into the blood stream. The absence of differences between pre- and post-operative serum enzyme activities has two possible explanations: Firstly, removal of previously released enzymes from the blood stream takes a much longer period than one month; and secondly, cancerous laryngeal tissue is not the only source of the enzymes mentioned even after removal of cancerous tissue by surgical operation, other sources such as adjacent tissues and/or metastatic tissues etc, still release these enzymes into the blood stream.

Superoxide Dismutase, Catalase, Glutathione Peroxidase and Xanthine Oxidase in Diabetic Rat Lenses

The activities of the protective enzymes, superoxide dismutase, catalase, glutathione peroxidase and of xanthine oxidase, an enzyme acting as a source of O–2, were measured in the lenses of alloxan-induced diabetic and control rats. Superoxide dismutase and glutathione peroxidase activities were found to be significantly decreased, while catalase and xanthine oxidase activities were increased. This means that the ratio of the oxidant/antioxidant enzymes increases in the diabetic rat lens, suggesting an increased oxidative stress. This imbalance is possibly an important contributing factor in the pathogenesis of diabetic cataract.

Concentrations of some major and minor elements in larynx tissues with and without cancer.

In this study, concentrations of some major and minor elements were determined in the larynx tissues with and without cancer, and results obtained were statistically compared. No meaningful differences were found between sodium, potassium, calcium and copper concentrations in cancer tissues, corresponding cancer-free adjacent tissues and in control larynx tissues. Phosphate concentrations of the cancer tissues were higher compared with cancer-free adjacent tissues and control tissues. Iron, zinc and magnesium concentrations were found increased in both cancer and corresponding cancer-free adjacent tissues relative to control values. Intra- and inter-element correlations established within and between groups indicated that relations between elements were also disordered in the cancer tissues. We suggest that the changed element status of cancerous larynx tissues may arise from increased requirements of cancer tissues for some elements such as iron, zinc, magnesium and phosphate.

Nickel, chromium, manganese, iron and aluminum levels in human cataractous and normal lenses.

Atomic absorption spectrophotometry was used to detect lenticular nickel, chromium, manganese, iron and aluminum levels in 37 senile cataractous and 9 normal human lenses. The nuclear parts of the lenses were used for the study in both groups. It was found that the concentrations of nickel and iron were significantly higher, and those of chromium, manganese and aluminum were significantly lower in human cataractous lenses than those in normal human lenses. None of the elements showed a significant difference according to sex in both groups. As remarkable differences in chromium, manganese, iron, aluminum and nickel levels exist in cataractous lenses, all the five elements may play some roles in cataractogenesis.

Adenosine deaminase, 5′-nucleotidase, xanthine oxidase, superoxide dismutase, and catalase activities in gastric juices from patients with gastric cancer, ulcer, and atrophic gastritis

Adenosine deaminase (ADA), 5′-Nucleotidase (5NT), Xanthine oxidase (XO), Cu-Zn Superoxide dismutase (SOD) and Catalase (CAT) activities were determined in gastric juices from patients with gastric cancer, ulcer, gastritis and from healthy subjects. Enzyme activities were given as units per ml gastric juice and units per mg protein in gastric juice. ADA, 5NT and XO activities were found lower and protein concentrations were found higher in the cancer group than controls. There was however no significant difference between Cu-Zn SOD activities of the cancer and control groups. In all groups including control one, we could not find catalase activities in most of the samples. On the other hand, ADA, 5NT activities and protein concentrations in the gastric juice were lower in the gastritis group than control group. In the ulcer group, we found higher Cu-Zn SOD and XO activities and lower 5NT activity and protein concentrations compared with control values. In an attempt to establish statistical correlations between mean enzyme activities, pH and protein concentrations in the gastric juices of the groups, we found noticeable intra and inter-correlations, which indicated possible relations between DNA and free radical metabolizing enzymes.

Antiviral Properties of Caffeic Acid Phenethyl Ester and Its Potential Application

Caffeic acid phenethyl ester (CAPE) is found in a variety of plants and well-known the active ingredient of the honeybee propolis. CAPE showed anti-inflammatory, anticarcinogenic, antimitogenic, antiviral, and immunomodulatory properties in several studies. The beneficial effects of CAPE on different health issues attracted scientists to make more studies on CAPE. Specifically, the anti-viral effects of CAPE and its molecular mechanisms may reveal the important properties of virus-induced diseases. CAPE and its targets may have important roles to design new therapeutics and understand the molecular mechanisms of virus-related diseases. In this mini-review, we summarize the antiviral effects of CAPE under the light of medical and chemical literature.