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OBJECTIVE: We aimed to evaluate the efficacy of low dose N-acetylcysteine (NAC) against myocardial ischemia-reperfusion damage in coronary artery bypass surgery accompanied by cardiopulmonary bypass (CPB). METHODS: Thirty patients operated due to triple coronary artery disease were enrolled into this prospective randomized study (control group - n=15 and NAC group - n=15). N-acetylcysteine was added to induction cardioplegia solution in dose of 4 mmol/l and in dose of 2 mmol/l to maintenance cardioplegia solution in the NAC group. Hemodynamic measurements were performed before and after anesthesia with different intervals. Creatine kinase-MB (CK-MB) levels were analyzed during 24 hours postoperatively. Blood samples were obtained from coronary sinus before CPB (T1), just before the cross-clamp removed (T2) and 30 minutes later (T3). Malondialdehyde (MDA), glutathione peroxidase (GSH-Px), nitric oxide (NO) levels and neutrophil percentage were determined. Statistical analysis was performed using student's t test, Chi-square and two-way ANOVA tests. RESULTS: There were no significant differences between the two groups with regard to the hemodynamic parameters, and CK-MB levels. The MDA levels were significantly lower in NAC group than in control group during reperfusion period (0.75 nmol/l vs 0.88 nmol/l, p<0.05). Neutrophil percentage in coronary sinus blood was significantly lower in NAC group than in control group during the reperfusion period (77.6% vs 82.7%, p<0.05). The GSH-Px and NO levels were also not statistically different between groups. CONCLUSION: Low dose NAC as an adjunct to cardioplegic solutions effectively reduces myocardial oxidative stress in coronary bypass surgery with cardiopulmonary bypass, but may not restore the myocardial injury. [ABSTRACT FROM AUTHOR]

Stinging nettle ( Urtica dioica L.,) is a medicinal herb commonly used by humans. The role of reactive oxygen metabolites on cancer etiology is known. There are some studies about the antioxidant effects of Urtica Dioica (UD) on therapy of some cancer types. This study aimed to investigate the effects of UD on antioxidant enzyme activities and mammary gland cancer induced by in rats-N-methyl-N-nitrosourea (NMU) carcinogenesis. Rats were divided into four groups: a untreated group (Group 1), a NMU group (Group 2) given 50 mg/kg NMU by intraperitoneal (i.p.) injection, a NMU group (Group 3) treated with UD, a control group (Group 4) fed with 50g/kg UD. After 5.5 months, rats were decapitated, and mammary tissue and blood samples were obtained. There was a significant (p<0.05, p<0.01, respectively) increase in plasma malondialdehyde (MDA) levels of group 2 compared with group 1 and 4. The superoxide dismutase (SOD) activity of the erythrocytes was decreased in group 3 than the other groups (p<0.0001). The erythrocyte catalase (CAT) activity was significantly increased in group 4 compared with group 2 and 3 (p<0.05, p<0.01, respectively). The number of animals with palpable tumors was 6 (46.15%) in group 2, and 2 (13.3%) in group 3 at the end of the 22nd week. Although group 3 had lower palpable tumor number than group 2, the difference was not statistically significant (p=0.096). The results showed that UD constituents may have effects on lipid peroxidation and some antioxidant enzyme activities, and may slow the formation of mammary tumor.

Background: Selenium, which is critical for human health, is necessary for various metabolic processes, including thyroid hormone metabolism, protection against oxidative stress, and immune function., Objective: The present study aims to examine how selenium administration affects lipid peroxidation in liver and lung tissues of rats subjected to acute swimming exercise., Methods: The study included 32 Spraque-Dawley adult male rats divided into Group 1 (general control), Group 2 (selenium-administered), Group 3 (swimming), and Group 4 (selenium-administered swimming). MDA and GSH levels were determined in liver and lung tissues., Results: The highest MDA values in the liver and lung tissues were found in group 3 in the study. MDA value in group 4 was higher than those in groups 1 and 2. Group 4 had the highest liver and lung GSH levels. GSH levels in Group 3 were higher than those in groups 1 and 2., Conclusion: Results of the study indicate that acute swimming exercise causes lipid peroxidation in liver and lung tissues, while selenium administration prevents free radical formation by increasing antioxidant activity (Tab. 2, Ref. 26).

Background: This study aims to examine how boron supplementation affects distribution of elements in the plasma of rats whose ovaries were removed and who were subjected to swimming exercise., Methods: The study included 80 Sprague-Dawley type female rats, which were equally allocated to 8 groups. Group 1: General control, Group 2: Exercise control; Group 3: Ovariectomized control, Group 4: Ovariectomized exercise, Group 5: IP (intraperitoneal) boron-supplemented control, Group 6: IP boron-supplemented exercise, Group 7: Ovariectomized, IP boron-supplemented exercise, group 8: Ovariectomized, IP boron-supplemented. Following the exercise, blood samples were collected from all animals by decapitation, and analyzed in terms of plasma copper, iron, phosphorus, magnesium, calcium, and zinc using an atomic absorption spectrophotometer., Results: Groups 1 and 5 had the lowest copper (p < 0.01) and the highest zinc and calcium (p < 0.01) levels, in comparison to other groups. Phosphorus levels in groups 3, 5 and 8 were significantly lower than those in other groups (p < 0.01). Magnesium levels in groups 3, 5 and 8 were higher, relative to the levels in other groups (p < 0.01)., Conclusion: Results of the study indicate that acute swimming exercise in ovariectomized rats supplemented with boron leads to significant modifications in the distribution of some trace elements in the plasma. It can be emphasized as a separate result of this study that changes in copper, zinc and calcium levels were independent of boron supplementation (Tab. 2, Ref. 14).

The objective of the present study was to determine the effects of exercise and zinc deficiency on some elements in rats. Forty adult male Sprague-Dawley species male rats were allocated to four groups as follows: Group 1: control, Group 2: zinc-deficient, Group 3: exercise in which exercise group fed with a normal diet, Group 4: zinc-deficient exercise, exercise group fed by a zinc-deficient diet for 15 days. After the procedure ended, rats in groups 3 and 4 were exercised on the treadmill for 60 min at a speed of 6 m/min until the exhaustion. The rats were decapitated 48 h after exercise together with their controls, and blood samples were collected to determine copper (Cu), iron (Fe), magnesium (Mg), calcium (Ca), and phosphorus (P) levels. The highest Cu and Fe values in the serum were obtained in group 2 (p < 0.01). The levels of these elements in group 4 were lower than those in group 2 and higher than the levels in groups 1 and 3 (p < 0.01). Serum Mg levels did not differ significantly between groups. Group 4 had the lowest serum Ca and P levels (p < 0.01). These same parameters in Group 2 were higher than those in group 4 but significantly lower than those in groups 1 and 3 (p < 0.01). There was no significant difference between Ca and P levels of groups 1 and 3. The results of the study indicate that zinc deficiency adversely affects copper, iron, calcium, and phosphorus mechanisms and that these adverse effects much more marked after an effort exercise.

In consideration of leptin effects such as reducing food intake and increasing energy consumption, many researchers have sought to examine the relation between leptin and exercise. The presence of reports arguing that zinc, can be a mediator in leptin production indicates a possible relation between zinc and leptin. The present study aims to determine plasma leptin levels in elite weightlifters and examine their relation with zinc. The study enrolled 30 healthy volunteers in the 18-27 age range. The subjects were allocated to groups in equal numbers: Group 1, CONTROL GROUP: the group included subjects who did not exercise regularly. Group 2, Elite Weightlifter Group: the group included elite weight lifters who were selected to the national team in their weight classes, who exercised regularly and whose values were measured during rest in the training period. Levels of plasma leptin and zinc were determined in the blood samples collected from the subjects included in the study. Comparison of serum leptin and zinc values between groups showed that leptin and zinc levels in the control group were significantly higher than those in the weightlifters and that leptin levels decreased significantly in parallel with the low zinc levels. It can be concluded that physical activity brings about changes in leptin secretion, which in turn, can be significantly related with zinc (p < 0.01)., (Copyright 2008 John Wiley & Sons, Ltd.)

Lead, widely used in industry, is a great environmental health problem. Many studies have examined its effects on the health of both humans and animals. Experimental studies have shown that sulphur-containing antioxidants have beneficial effects against the detrimental properties of lead. The present study was designed to investigate markers of oxidative stress (hemoglobin (Hb) in whole blood, malondialdehyde (MDA) in sera; superoxidase dismutase (SOD) and glutathione peroxidise (GSH-Px) in erythrocyte hemolysate and vitamins A and E in plasma) in rats given lead (2000ppm) with or without sulphur-containing antioxidants (l-methionine (Met) (100mg/kg/day), N-acetylcysteine (NAC) (800mg/kg/day), l-homocysteine (Hcy) (25mg/kg/day), lipoic acid (LA) (50mg/kg/day)) in their water for 5 weeks. In the lead group, Hb and plasma vitamin E levels were significantly lower whereas MDA levels were significantly higher compared to controls (p<0.05). Hb levels in lead-methionine and lead-LA groups were significantly higher than the lead group (p<0.01). MDA levels were reduced in all groups compared to the lead group (p<0.01). There was a decrease below control values in erythrocyte SOD (p<0.01) and GSH-Px (p<0.05) levels in the lead-LA group. Plasma vitamin A levels were significantly high in lead-methionine group compared to lead group (p<0.01). In conclusion, the data suggests that oxidative stress induced by lead is reduced by sulphur-containing compounds.

Polychlorinated biphenyls (PCBs) are persistent environmental pollutants. This study compared effects of two PCB mixtures, Aroclors 1221 (A1221) and 1254 (A1254) on serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), urea, creatinine and uric acid in female rats. Histopathological changes in the liver and kidney were also examined. A group of adult Wistar rats served as controls. Groups II and III were subcutaneously injected with A1221 and A1254 at 10 mg/kg every other day for 6 weeks. At the end of this period, all animals were decapitated and blood samples were collected. Serum urea, creatinine, uric acid, ALT, AST and ALP levels were determined. Liver and kidney were collected for histopathological examination. They were fixed in formaldehyde and processed for light microscopy. Both A1221 and 1254 significantly elevated serum ALT (p < 0.05) and AST (p < 0.01) levels compared to the control group. Serum ALP values were significantly increased by A1221 (p < 0.05), but they were unaffected in the A1254 group. Treatment with both A1221 and A1254 significantly increased serum levels of urea (p < 0.05), creatinine (p < 0.01) and uric acid (except in the A1221 group; p < 0.005). Distinct histopathological changes including renal corpuscular atrophy, peritubular vascular congestion and dilated cortical tubules, sinusoidal dilatation, congestion and mononuclear cell infiltration were observed. These findings suggest that PCBs may cause nephrotoxicity and hepatotoxicity in female rats., (Copyright 2005 John Wiley & Sons, Ltd.)

Introduction: Behçet's disease is a rare, chronic disorder. The cause of Behçet's disease is unknown. It is believed to be caused by an autoimmune reaction. As in other chronic autoimmune diseases, Behçet's disease may show a subclinical adrenal failure and some changes in cortisol levels. We aimed to evaluate adrenal gland function in Behçet's disease patients., Material and Method: This study included 18 Behçet's disease patients and 15 healthy controls. Patient and control groups were administered i.v. 1 microg low dose test (LDT) and 250 microg standard dose test (SDT) adrenocorticotropic hormone (ACTH) stimulation test after 12 h of night fasting with an interval of 3-days and cortisol responses in the 0th, 30th and 60th minutes were evaluated., Results: There was no statistically significant difference between basal cortisol values of Behçet's disease and control groups. Cortisol values in the 60th minute in LDT were significantly lower in Behçet's disease group than in the control group. In the peak cortisol responses to LDT, a significant decrease was found in Behçet's disease group., Conclusion: These findings suggest that hypothalamo-pituitary adrenal axis is partially suppressed in Behçet's disease.

It has been well documented that human milk contains several immunomodulator components which are important during infant period when the newborn's immune system is still under development. In this study, we aim at examining levels of cytokines, zinc (Zn), and copper (Cu) in milk from mothers of premature and mature infants, and comparing changes during lactation periods consequently. Milk was collected from total of 40 mothers (group M: mothers of mature infants, n = 20; group PM: mothers of premature infants, n = 20) from four lactation stages: colostrum (0-7 days), transitional (7-14 days), mature milk (21 days), and mature milk (2nd month). Levels of cytokines (interleukin [IL]-lbeta, IL-2, IL-6, IL-8, tumor necrosis factor-alpha [TNF-alpha]) were determined by chemiluminesence method, whereas atomic absorption spectrophotometer was used for the determination of Zn and Cu levels. Cytokine levels were determined to be high in colostrum and transient milk from mothers of full-term infants, whereas their levels were reduced drastically in the 21st day and the 2nd month milk (P < .01, P < .001). Similar trends were observed in milk from mothers of premature infants, but cytokine levels were significantly lower in colostrum compared to colostrum from mothers of mature infants (P < .01). The differences in cytokine levels were continuous in transient milk (P < .05) and mature milk (21 days) (P < .05), whereas there was no statistically significant differences between milk from both groups of mothers in the 2nd month (P > .05). Zn levels in milk from mothers of premature infants were significantly lower compared to the ones from mothers of mature infants (P < .01) and these differences continued through the 2nd month. Although Cu levels were lower in milk from mothers of premature infants, there was no statistically significant difference except colostrum (P > .05). Our results clearly demonstrate that the level of immunomodulating agents such as cytokines and trace elements in milk from mothers of premature infants is less than the level of the same agents in milk from mothers of full-term infants. Although there are commercially available products for infant feeding, human milk is still the best natural nutrient for newborns. Therefore, when premature infants are breastfed, necessary precautions such as supplemantary diets must be considered for possible infections and risks related with immune system deficiency.

Objective: The role of leptin in the acute stress response to extracorporeal circulation has been well documented, however, the relationship between leptin and zinc has not been investigated previously. We aimed to research the circulating leptin, zinc, and copper levels before, during, and after the extracorporeal circulation, and effect of preoperative zinc administration to these., Methods: Twenty patients who were taken to elective coronary artery bypass grafting operations using extracorporeal circulation were taken to this research and divided into two equal groups (n1, n2). In both groups blood samples were taken just before the operation (T0), at the end of operation (T1), and at the first postoperative day (T2). In the second group (n2) oral zinc (50 mg, once a day) was administered to patients for 5 days, preoperatively. The serum leptin, zinc, and copper levels were studied., Results: In group n1 circulating leptin levels were significantly increased at T2 when compared to T0 and T1 (p<0.05); zinc levels were decreased at T2 when compared to T0 and T1 (p<0.05); copper levels were decreased at T2 when compared to T0 (p<0.05), and decreased at T1 when compared to T0 (p<0.05). In group n2 circulating leptin levels were significantly increased at T2 when compared to T0 and T1 (p<0.05); zinc levels were decreased at T2 when compared to T0 and T1 (p<0.05); copper levels were increased at T2 when compared to T1 (p<0.05)., Conclusions: These results indicate that circulating leptin levels increase after the extracorporeal circulation as an acute response, while zinc and copper levels decrease at the same period. Preoperative zinc administration does not prevent the leptin response after extracorporeal circulation.

In the last 10 years, saliva has been increasingly used as a diagnostic fluid and in predictions of disease progression. Leptin and ghrelin are synthesized in several tissues including the salivary glands. The action of ghrelin is antagonistic to that of leptin. This study was undertaken to measure and compare the saliva ghrelin-leptin and plasma ghrelin-leptin levels in healthy young subjects. In 30 healthy subjects, after an overnight fast, saliva and plasma leptin levels were measured using the ELISA method while saliva and plasma immunoreactive ghrelin levels were measured using a commercial radioimmunoassay (RIA). The latter uses 125I-labeled bioactive ghrelin as a tracer and a rabbit polyclonal antibody raised against full-length octanoylated human ghrelin (Phoenix, Europe, Karlsruhe, Germany). The results of this investigation revealed that saliva leptin levels (6.19+/-2.10 microg/l) were lower than plasma levels (7.39+/-3.23 microg/l) while saliva ghrelin levels (188.5+/-84.7 pg/ml) were higher than plasma levels (126.4+/-38.5 pg/ml), when male and female subjects were considered together. Saliva leptin levels (5.93+/-1.94 microg/l) were lower than plasma levels (6.22+/-2.92 pg/ml) while saliva ghrelin levels (190.3+/-80.2 pg/ml) were higher than plasma levels (120.4+/-35.7 pg/ml) in young males. Saliva leptin levels (6.47+/-2.29 microg/l) were lower than plasma levels (8.73+/-3.14 microg/l) while saliva ghrelin levels (183.2+/-90.2 pg/ml) were higher than plasma levels (129.3+/-42.8 pg/ml) in young females, and both saliva and plasma leptin levels were slightly lower in male subjects in comparison with female subjects. Also, Immunohistochemistry study indicated that ghrelin positivity was found in ductus epithelium of salivary gland. We have demonstrated for the first time that saliva ghrelin levels were higher than in plasma while saliva leptin levels were almost the same as in plasma. Measurements of ghrelin and leptin in saliva is non-invasive, simple, and generally much preferred by patients and thus may be an acceptable alternative to plasma sampling.

The effects of zinc deficiency and supplementation on plasma leptin levels were studied in Sprague-Dawley rats. After 6 wk on a zinc-deficient diet containing 0.65 ppm Zn/g, the mean body weight was significantly lower than that of normal or zinc-supplemented rats, which showed no difference among them. The plasma leptin and zinc levels were lowest in zinc-deficient animals and highest in those that received a normal diet and daily intraperitioneal injections of 3 mg Zn/kg. These results indicate that zinc deficiency leads to a significant inhibition in plasma leptin levels, whereas zinc supplementation significantly increases plasma leptin.

Obesity is among the main contributing factors in the etiology of essential hypertension (EHT). Leptin, the product of the ob gene, is expressed mainly in adipose tissue. We examined the relationship between two trace elements, zinc (Zn) and copper (Cu), and leptin in patients with EHT (n=35) and normotensive (NT) controls (n=50) because leptin as well as Zn and Cu were reported to be associated with the pathophysiology of EHT. Plasma leptin levels were determined with a commercial enzyme-linked immunosorbent assay (ELISA) kit. Atomic absorption spectrophotometry was utilized to determine plasma Zn and Cu levels. There was a negative correlation between leptin and Zn, and the Zn/Cu ratio (r= -0.359, p<0.05; r= -0.361, p<0.05, respectively) in pooled subjects. When subjects were divided based on the presence or absence of hypertension, there was a negative correlation between leptin and Zn (r= -0.375, p<0.05) as well as leptin and Zn/Cu ratio (r= -0.398, p<0.05) in NT subjects. Similar trends were observed when leptin/BMI (body mass index) levels were utilized. There was no significant correlations between levels of Cu and leptin or leptin/BMI. In conclusion, in addition to high leptin levels, Zn and the Zn/Cu ratio were lower in patients with EHT compared to NT controls.

Platelet aggregation was measured by an optical method in 32 patients with iron-deficiency anemia at the time of diagnosis and after a period of supplementation with iron. Epinephrine- and adenosine diphosphate-induced platelet aggregation were lower in anemic patients than in the controls (p<0.05). After iron-supplementation therapy, these values showed no significant differences. If induced by collagen or ristocetin, platelet aggregation was the same for patients and controls, but increased after treatment of patients (p<0.05). The plasma zinc values did not show significant differences among the subjects included in this study. These results show that iron is involved in the enzymatic systems that regulate platelet aggregation. The exact nature of this interaction is still to be determined.

Increased serum homocysteine (Hcy) can induce liver diseases and can play a remarkable role in hepatic disorders. The purpose of the present study therefore was to investigate the relationship between serum vitamin B(12), folate, zinc and copper, cysteine, and Hcy level differences between cirrhotic patients and healthy subjects. We studied 32 cirrhotic patients (12 females and 20 males) aged 45 +/- 11 years and 32 control subjects (12 females and 20 males) aged 39 +/- 9 years. There was an inverse correlation between Hcy and vitamin B(12) in controls (r = -0.442, p < 0.011) but not in cirrhotic patients (r = -0.147, not significant). Also, mean plasma folate was decreased in cirrhotic patients compared to controls (p < 0.001). Copper increased whereas zinc decreased significantly in cirrhotic patients. A positive correlation was seen between the Cu/Zn ratio and Cu in controls (r = 0.690, p < 0.01), but the correlation between the Cu/Zn ratio and Cu was not significant in the cirrhotic group. Negative correlations were seen between plasma concentration of zinc and the Cu/Zn ratio in controls and cirrhotic patients (r = -0.618, p < 0.01 and r = -0.670, p < 0.01, respectively). Cirrhotic patients displayed multiple abnormalities, including changes in cysteine metabolism and in zinc and copper levels. Although hyperhomocysteinemia is known as an atherogenic and thrombogenic risk factor for cardiovascular disease, it might also be a risk factor for cirrhotic patients. Plasma Hcy, vitamin B(12), and folic acid measurement may be useful in the evaluation of cirrhotic patients.

Objective: The aim of the present study was to determine the levels of homocysteine, folic acid, and Vitamin B12 in subjects with noise-induced hearing loss. Furthermore, possible links between these parameters and noise-induced hearing loss were aimed to be evaluated., Methods: In the present study, blood samples were obtained from all subjects after overnight fasting for biochemical analysis. We examined the levels of homocysteine, Vitamin B12 and folic acid levels in subjects with noise-induced hearing loss. Twenty-eight male patients with noise-induced hearing loss (mean age 37 +/- 5 year) were included in the study group whereas the control group was composed of 32 healthy male volunteers (mean age 36 +/- 4 year)., Results: It was found that homocysteine levels of subjects with noise-induced hearing loss as significantly high compared to healthy controls (P < 0.05). On the other hand, Vitamin B12 and folic acid levels of patients with noise-induced hearing loss were determined to be significantly low compared to the controls (P < 0.05 and < 0.01, respectively)., Conclusion: Our findings indicate that there might be a link between increased homocysteine levels and noise-induced hearing loss. Since increased homocysteine levels cause elevated levels of free radicals in addition to its atherogenic and thrombogenic effects. Further experimental studies are needed to decipher how this relationship is linked.

While pathogenesis of hypertension is not clearly deciphered yet, increase in body weight, most of the time, is associated with hypertension. There are reports indicating that leptin, product of the Ob gene mainly synthesized in adipocytes, may have role(s) in hypertension, but contribution of the gender is rather contradictive. In the present study, plasma leptin levels in patients of both genders with hypertension and normotensive controls were measured and the relationship between plasma leptin levels and BMI were evaluated in both sexes. Total of 62 patients (31 M/31 F) diagnosed with essential hypertension who were not under any antihypertensive medication were admitted into the study. The control group was composed of 56 (25 M/31 F) age-, BMI- and sex-matched healthy normotensive volunteers. Plasma leptin levels were determined by a commercial ELISA kit. Plasma leptin and leptin/BMI levels (Mean +/- SEM) of women (n:62) were significantly higher than men (n:56) (20.10 +/- 1.47 ng/ml versus 4.72 +/- 0.50 ng/ml; p < 0.0001). Plasma leptin and leptin/BMI levels of patients of both genders with hypertension were significantly higher than in normotensive subjects (p < 0.05). Leptin and leptin/BMI levels in obese hypertensives were higher than obese normotensives (p < 0.05). Obese hypertensive women had higher leptin and leptin/BMI levels than obese normotensive women (p < 0.05). In conclusion, these results support the hypothesis that a possible link exists between leptin and hypertension. Further studies are needed to clarify how increased levels of leptin affects the pathophysiology of hypertension.

Background & Objectives: Rheumatoid arthritis (RA) is a debilitating, chronic multisystem disease with an unknown etiology. Recent findings indicate that increased oxidative stress and/or defective antioxidant status contribute to the etiology of RA. The present study was undertaken to examine the oxidant and antioxidant systems in patients with RA and healthy controls., Methods: Twenty two patients with RA and 20 healthy volunteers were included in the study. Levels of malondialdehyde (MDA) and antioxidant vitamins (A, E, C) in serum samples were determined by high performance liquid chromatography (HPLC). Spectrophotometric methods were used to determine activity levels of antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), in erythrocytes., Results: MDA levels in patients with RA were found to be significantly (P<0.005) higher than controls whereas levels of vitamins A, E, C and activities of GSH-Px, SOD were lower in the patients compared to controls (P<0.005 for SOD and antioxidant vitamins; P<0.05 for GSH-Px)., Interpretation & Conclusion: There was an increased oxidative stress and a low antioxidant status in patients with RA. These changes are probably due to efforts for reducing lipid peroxidation and hence to lower tissue damage.

In the present study estrogen or testosterone was administered to broiler chickens (6 weeks old) for 5 weeks and levels of antioxidant vitamins (A, E and C) and selenium (Se) were determined. In animals who received estrogen, vitamins A, E, C and Se levels were 0.70 +/- 0.19, 11.0 +/- 2.45, 20.0 +/- 5.17 and 130.0 +/- 25.0 microg l(-1), respectively. Vitamins A, E, C and Se levels in the testosterone-administered group were found to be 0.54 +/- 0.16, 9.9 +/- 1.96, 18.0 +/- 5.18 and 100.0 +/- 18.0 microg l(-1), respectively. Vitamins A, E, C and Se levels were found to be significantly increased in the estrogen-administered group compared to the controls (p < 0.01, p < 0.01, p < 0.05, p < 0.05, respectively). Although all parameters were increased in testosterone-treated animals, only increases in vitamins A and E were found to be statistically significant (p < 0.01, p < 0.01, respectively). Based on the present findings, estrogen and testosterone show direct antioxidant effects by increasing the activities of some enzymes and they also cause an increase in antioxidant vitamin levels and hence indirectly also contribute to antioxidant capacity., (Copyright 2002 John Wiley & Sons, Ltd.)

Functional irregularities due to damage after ischaemia-reperfusion vary depending upon the organs affected. High energy phosphates such as ATP and ADP are destroyed after ischaemia-reperfusion damage. Subsequently, protons and inorganic phosphates accumulate within the cells and the proton pumps such as adenosine triphosphatase (ATPase), which maintain intracellular ion balance are damaged. In the present study, malondialdehyde (MDA), a product of lipid peroxidation, was measured as an indicator of tissue damage. Additionally, we measured sodium-potassium-ATPase levels and determined the interactions between MDA and Na+-K+ ATPase levels. A total of 31 female guinea pigs were divided into four groups: sham operated guinea pigs (group 1), ischaemia-reperfusion (group 2), ischaemia-reperfusion + superoxide dismutase (SOD) (group 3), ischaemia-reperfusion + allopurinol (group 4). Following reperfusion, the livers of guinea pigs in each group were removed for histopathological examination and the levels of MDA and Na+-K+ ATPase were determined in homogenized tissue samples. There was a statistically significant (p < 0.05) reduction in tissue MDA levels in group 2 when compared with group 1. The level of tissue MDA in groups 3 and 4 was significantly lower than tissue MDA levels of group 2. However, there was a statistically significant (p < 0.05) reduction in tissue Na+-K+ ATPase levels of group 2 when compared with group 1. Similarly, the level of tissue Na+-K+ ATPase in groups 3 and 4 was significantly higher than the tissue Na+-K+ ATPase levels of group 2. The results of the histopathologic examination also revealed the beneficial effects of the use of SOD and allopurinol in preventing liver damage in cases of ischaemia-reperfusion. Although the levels of MDA and Na+-K+ ATP ase in group 2 were not equal to the level in group 1, antioxidant therapy significantly improved the tendency to reverse the effects of ischaemia-reperfusion and to protect the liver from damage due to ischaemia-reperfusion., (Copyright 2001 John Wiley & Sons, Ltd.)

Paint thinner is a commonly used industrial solvent with considerable potential for abuse by inhalation. Paint thinner is taken into the body by inhalation or by contact with the skin. Paint thinner is oxidized gradually by cytochrome P450-dependent monooxygenase and consequently free radicals are produced. In the present study we measured plasma malondialdehyde (MDA, a product of lipid peroxidation) levels as an indicator of oxidative damage and activity levels of antioxidant enzymes gluthatione peroxidase (GSH-Px) and superoxide dismutase (SOD) in erythrocytes of a group of people (n = 18) working with paint thinner. The control group was composed of 18 healthy adults. There was a statistically significant (p < 0.001) increase in MDA (2.0+/-0.7 nmol ml(-1)) and GSH-Px (86.5+/-16.6 U g(-1) Hb) activity levels in people working with paint thinner compared with control subjects (MDA: 1.0+/-0.3 nmol ml(-1); GSH-Px: 53.9+/-14.5 U g(-1) Hb). Similarly, there was also an increase (p < 0.05) in the SOD levels (1079+/-214.6 U g(-1) Hb) of people working with paint thinner compared with controls (953.3+/-46.7 U g(-1) Hb). Based on our results, it can be concluded that paint thinner inhalation may increase lipid peroxidation and consequently induce antioxidant enzymes., (Copyright 2000 John Wiley & Sons, Ltd.)

Aims: Effect of exogenously administered melatonin (N-acetyl 5-methoxytryptamine) on antioxidant systems in experimental Ischemia-Reperfusion (I-R) of rat gastrointestinal system (GIS) was examined., Methods: A total of 40 rats were divided into 4 groups: Group 1 (Sham), Group 2 (I-R), Group 3 (I-R + 10 mg/kg melatonin) and Group 4 (I-R + 20 mg/kg melatonin). Activity levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined in small intestines., Results: There was a significant (p<0.05) reduction in GSH-Px levels in Group 2 (64.16+/-7.02 U/mg protein) compared to Group 1 (80.15+/-9.32 U/mg protein). We observed a meaningful increase in GSH-Px levels in melatonin applied groups (Group 3: 75.94+/-9.83 U/mg protein, Group 4: 78.55+/-9.11 U/mg protein) compared to Group 2. Correspondingly, SOD activity levels were significantly reduced (p<0.001) in Group 2 (24.14+/-4.35 U/mg protein) compared to controls (52.91+/-6.13 U/mg protein). A stronger effect (p<0.001) of melatonin was observed on SOD levels compared to GSH-Px levels in both doses (Group 3: 38.96+/-6.39 U/mg protein, Group 4: 43.07+/-7.76 U/mg protein). Levels of selenium were reduced significantly in Group 2 (1.11+/-0.31 microg/g tissue) compared to Group 1 (2.01+/-0.19 microg/g tissue). Melatonin application in Group 3 (1.13+/-0.28 microg/g tissue) and Group 4 (1.89+/-0.48 microg/g tissue) caused an increase in selenium levels. There was a strong correlation between increases in selenium and GSH-Px levels in Group 4 (r:0.651 p<0.01)., Conclusions: Melatonin seems to exert its antioxidant effect in GIS tract by stimulating SOD and GSH-Px. Selenium also seems to have an antioxidant contribution on protecting rat gastrointestinal tract I-R injury., (Copyright 2000 S. Karger AG, Basel.)