Xanthine oxidase enzyme activity in keratoconic corneal epithelium.

PURPOSE: To assess the activity of xanthine oxidase (XO) enzyme in keratoconic corneal epithelium and to evaluate its relationship with the keratoconus (KC) severity. METHODS: This prospective and randomized study included 66 eyes of 54 KC patients who received corneal collagen cross-linking treatment and 43 eyes of 32 patients who underwent photorefractive keratectomy due to their refractive error. During surgical procedures, the corneal epithelium was mechanically scraped and gathered to analyze the XO enzyme activity spectrophotometrically. The KC group was subdivided into three groups (stages 1, 2, and 3) according to the Amsler-Krumeich classification. The results were compared between the KC and the control group and in between KC subgroups. RESULTS: No significant differences in age and gender were found between the KC and control groups (p = 0.064 and p = 0.296, respectively). The mean XO activity levels of the KC and control groups were 173.57 ± 87.61 and 223.70 ± 99.52 mIU/mg, respectively (p < 0.001). In KC group, 33 eyes were at stage 1, 19 were at stage 2, and 14 were at stage 3. No significant difference was observed between KC subgroups regarding XO activity levels (p = 0.681). CONCLUSION: In this study, our findings revealed that ultraviolet-related pro-oxidant XO enzyme may have a role in the etiopathogenesis of KC. Further studies are needed to support our result. CLINICAL TRIALS REGISTRATION: When we started this study in 2018, we did not have a "Clinical Trials Registration." However, we have ethics committee approval (date: 21. 02. 2018/No: 22).

Association of oxidative stress with clinical characteristics in patients with rheumatoid arthritis.

BACKGROUND: Few studies examining the association between oxidative stress and clinical parameters or disease activity in patients with rheumatoid arthritis (RA) are available. Therefore, the objective of this study was to test whether oxidative stress has any association with clinical parameters and disease activity in patients with RA. MATERIALS AND METHODS: In this post hoc cross-sectional study, 45 patients with RA treated with traditional disease-modifying antirheumatic drugs (DMARDs) ± low-dose glucocorticoids ± nonsteroidal analgesics for at least 3 months were analysed. Oxidative stress parameters were malondialdehyde (MDA), superoxide dismutase (SOD), antioxidant potential (AOP) and nonenzymatic superoxide radical scavenger activity (NSSA). Clinical parameters were pain, patient global assessment, physician global assessment, Health Assessment Questionnaire (HAQ), and disease activity score (DAS28). RESULTS: Plasma NSSA levels were significantly inversely correlated with tender joints count (r = -.304; P = .042), swollen joints count (r = -.342; P = .021) and DAS28 (r = -.396; P = .009). There were no significant correlations between MDA/SOD/AOP and any of clinical parameters or DAS28 (P > .05 for all). Multiple regression analysis revealed that NSSA was an independent variable of DAS28 (ß=-.243, P = .016). CONCLUSION: The preliminary results demonstrate that plasma NSSA levels were inversely correlated with tender and swollen joints count and DAS28 and that NSSA was independently associated with DAS28, in patients with RA treated with traditional DMARDs; and provide initial support that NSSA may be used as a biomarker of disease activity in patients with RA.

Serum glutathione peroxidase, xanthine oxidase, and superoxide dismutase activities and malondialdehyde levels in patients with Parkinson's disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). Oxidative stress has been hypothesized to play a major role in the development of PD in various studies. This study assessed to investigate oxidative and anti-oxidative status in PD patients. We evaluated oxidant/antioxidant status by measuring serum malondialdehyde (MDA) levels, xanthine oxidase (XO) activities, and activities of antioxidant enzymes, namely, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). The study included 29 patients with PD and 32 healthy subjects as controls. Comparison of oxidative parameters in the patient and control groups revealed significantly higher GSH-Px and XO activities in the patient group. Serum MDA and SOD activities in PD patients were not significantly different from the controls. MDA was negatively correlated with duration of the PD and positively with age of onset. There was a negative correlation between SOD and Hoehn and Yahr (H&Y) stage. According to these results, we suggest that oxidative stress may contribute to the development of PD.

Effect of spa therapy with saline balneotherapy on oxidant/antioxidant status in patients with rheumatoid arthritis: a single-blind randomized controlled trial.

Oxidative stress has been shown to play a contributory role in the pathogenesis of rheumatoid arthritis (RA). Recent studies have provided evidence for antioxidant properties of spa therapy. The purpose of this study is to investigate whether spa therapy with saline balneotherapy has any influence on the oxidant/antioxidant status in patients with RA and to assess clinical effects of spa therapy. In this investigator-blind randomized controlled trial, we randomly assigned 50 patients in a 1:1 ratio to spa therapy plus standard drug treatment (spa group) or standard drug treatment alone (control group). Spa group followed a 2-week course of spa therapy regimen consisting of a total of 12 balneotherapy sessions in a thermal mineral water pool at 36-37 °C for 20 min every day except Sunday. All clinical and biochemical parameters were assessed at baseline and after spa therapy (2 weeks). The clinical parameters were pain intensity, patient global assessment, physician global assessment, Health Assessment Questionnaire disability index (HAQ-DI), Disease Activity Score for 28-joints based on erythrocyte sedimentation rate (DAS28-4[ESR]). Oxidative status parameters were malondialdehyde (MDA), nonenzymatic superoxide radical scavenger activity (NSSA), antioxidant potential (AOP), and superoxide dismutase (SOD). The NSSA levels were increased significantly in the spa group (p = 0.003) but not in the control group (p = 0.509); and there was a trend in favor of spa therapy for improvements in NSSA levels compared to control (p = 0.091). Significant clinical improvement was found in the spa group compared to the control in terms of patient global assessment (p = 0.011), physician global assessment (p = 0.043), function (HAQ-DI) (p = 0.037), disease activity (DAS28-4[ESR]) (0.044) and swollen joint count (0.009), and a trend toward improvement in pain scores (0.057). Spa therapy with saline balneotherapy exerts antioxidant effect in patients with RA as reflected by the increase in NSSA levels after spa therapy; whether this antioxidant effect contributes to the clinical improvements observed remains to be verified.

Antioxidative-oxidative balance in epilepsy patients on antiepileptic therapy: a prospective case-control study.

Oxidative stress has been implicated in various disorders, including epilepsy. The aim of this study was to investigate the oxidant and antioxidant status of patients with epilepsy using antiepileptic drugs regularly and to compare them with healthy subjects. We investigated serum catalase (CAT), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and xanthine oxidase (XO) levels in 58 epilepsy patients and 25 healthy controls. Patients were divided into polytherapy (n = 17) and monotherapy (n = 41) groups, and antioxidant status was compared between the two groups and controls. There was no significant difference between the patient and control groups in terms of age or gender (p > 0.05). The mean duration of illness in the patients was 14.8 years, and the mean duration of treatment was 11.4 years. Comparison of the patient and control groups in terms of oxidative stress and antioxidant defence parameters revealed significantly higher MDA, GSH-Px, XO and lower level of CAT, SOD levels (p < 0.05). There were no differences in CAT, MDA, GSH-Px or SOD levels between the monotherapy and polytherapy groups; but the XO level was higher in the monotherapy group (p < 0.05). Although the XO level was decreased by polytherapy, it was higher than in controls. Our study found significantly low level of antioxidants in patients with epilepsy as compared to control. Thus, antiepileptic treatment did not improve oxidative stress parameters. Furthermore, our results show that polytherapy does not change the situation as compared with monotherapy. Antioxidant replacement therapy may benefit these patients.

Oxidative and nitrosative stress in serum of patients with Parkinson's disease.

Parkinson's disease (PD) is one of the common neurodegenerative disorders. Oxidative stress is considered as a contributing factor to the development of PD. The present study aims to investigate serum oxidative stress status in patients with PD. Oxidative stress was assessed by measuring serum nitric oxide levels, lipid hydroperoxide concentrations, and nitric oxide synthase activity. In addition, total serum antioxidant capacity (TAC) was evaluated using the serum 2,2-Diphenyl-1-picryl-hydrazyl (DPPH) free-radical scavenging method in 32 patient with Parkinson's disease and 32 control subjects. Our results indicated that serum nitric oxide and lipid hydroperoxide levels were significantly lower in patients with PD than controls. Moreover, nitric oxide levels were found to be negatively correlated with Unified Parkinson's Disease Rating Scale (UPDRS). However, no statistical difference was observed in total serum antioxidant capacities and nitric oxide synthase activities between patients and controls. The present study indicates that although antioxidant capacity was not changed, lipid hydroperoxide (LPO) level was found decreased. This might show pre-oxidative process in these patients. In addition, decreased nitric oxide (NO) level and negative correlation observed between NO level and disease rating scale implicated a role for NO in the disease process.

Serum oxidant and antioxidant status of patients with chronic tension-type headache: possible effects of medical treatment.

Tension-type headache (TTH) is one of the most common and costly primary types of headache in clinical practice, with an unknown etiology. This study assessed to investigate oxidative and antioxidative status in patients with chronic tension-type headache (CTTH), and to evaluate possible effect of medical treatment. The study included 41 CTTH patients and 19 age- and sex-matched healthy subjects without headache as controls. The CTTH group comprised 20 patients receiving treatment and 21 untreated patients. We evaluated oxidant/antioxidant status by measuring serum malondialdehyde (MDA) levels and activities of antioxidant enzymes, namely glutathione peroxidase (GSH-Px) and catalase (CAT). Comparison of oxidative parameters in the patient and control groups revealed significantly lower CAT activities and higher MDA level and GSH-Px activities in the patient group. In the CTTH group, serum CAT activities were found to be significantly decreased in patient groups, while serum MDA levels and GSH-Px activities were found to be higher in the untreated CTTH patients. These findings suggest that oxidative stress is increased in the patients with CTTH, and medical treatment abolishes the stress in part. It has been concluded that antioxidant support might be helpful for the patients with CTTH to prevent oxidant stress and peroxidation damages further.

Decreased antioxidant status in migraine patients with brain white matter hyperintensities.

Migraine patients have an increased risk to develop deep white matter hyperintensities (WMH) than the general population. Oxidative stress is believed to play a role in the pathogenesis of migraine. The present study was undertaken to assess oxidant/antioxidant balance of migraineurs with and without WMH. We hypothesized that increased oxidative stress and decreased antioxidant response may play a role in the pathophysiology of WMH in migraineurs. The study included 32 patients in the migraine group and 17 age- and sex-matched healthy subjects without headache in the control group. The migraine group comprised 18 with WMH and 14 without WMH. We evaluated oxidative status with malondialdehyde (MDA) and to determine the activities of antioxidant enzymes: superoxide dismutase, glutathione peroxidase and catalase (CAT) in serum of migraineurs and controls. Comparison of the patient and control groups for oxidative parameters revealed significantly lower level of CAT and higher level of MDA in the patient group. Two-way comparison for CAT and MDA of the migraine with and without WMH and the controls revealed that CAT serum level significantly decreased in migraine patients with WMH than migraine patients without WMH and controls. In this preliminary study, we demonstrated that the levels of CAT were decreased in migraine patients with WMH compared to patients without WMH and controls. These findings suggest that decreased antioxidant response may play a role in the pathophysiology of WMH in migraineurs. Besides, our results encourage the new treatment and follow-up options based on antioxidant systems.

Effects of computer monitor-emitted radiation on oxidant/antioxidant balance in cornea and lens from rats.

PURPOSE: This study aims to investigate the possible effects of computer monitor-emitted radiation on the oxidant/antioxidant balance in corneal and lens tissues and to observe any protective effects of vitamin C (vit C). METHODS: Four groups (PC monitor, PC monitor plus vitamin C, vitamin C, and control) each consisting of ten Wistar rats were studied. The study lasted for three weeks. Vitamin C was administered in oral doses of 250 mg/kg/day. The computer and computer plus vitamin C groups were exposed to computer monitors while the other groups were not. Malondialdehyde (MDA) levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities were measured in corneal and lens tissues of the rats. RESULTS: In corneal tissue, MDA levels and CAT activity were found to increase in the computer group compared with the control group. In the computer plus vitamin C group, MDA level, SOD, and GSH-Px activities were higher and CAT activity lower than those in the computer and control groups. Regarding lens tissue, in the computer group, MDA levels and GSH-Px activity were found to increase, as compared to the control and computer plus vitamin C groups, and SOD activity was higher than that of the control group. In the computer plus vitamin C group, SOD activity was found to be higher and CAT activity to be lower than those in the control group. CONCLUSION: The results of this study suggest that computer-monitor radiation leads to oxidative stress in the corneal and lens tissues, and that vitamin C may prevent oxidative effects in the lens.

Hepatic oxidant/antioxidant status in cholesterol-fed rabbits: Effects of garlic extract.

AIM: The investigation of oxidant/antioxidant status in hepatic tissues from cholesterol-fed rabbits and the establishment of possible protective effects of aqueous garlic extract on cholesterol-induced hepatic steatosis. METHODS: Twenty-two of 31 white New Zealand rabbits were given cholesterol (0.5 g/kg/day) for 4 months. Seven of them were then killed (cholesterol group). The remaining 15 animals were divided into two groups. Seven were fed on a normal laboratory diet (normal diet group) and the others (extract group) on a normal diet plus garlic extract (1.5 ml/kg/day) for an additional 3 months. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) enzyme activities, antioxidant potential (AOP) value, malondialdehyde (MDA), cholesterol and triglyceride levels in the liver tissues and total cholesterol and triglyceride levels in serum samples were measured. An histological evaluation was also done. RESULTS: An impaired antioxidant system, reduced antioxidant defence potential and increased peroxidation were found in hepatic steatotic tissues from cholesterol-fed animals. Treatment with garlic extract caused a significant increase in antioxidant potential and partly eliminated peroxidation damage in the hepatic tissue. Additionally, the extract caused significant reductions in the cholesterol levels of blood and hepatic tissues. The histological evaluations were in accordance with these results. CONCLUSION: The results suggest that cholesterol-induced steatosis leads to a weakened antioxidant defence system and causes peroxidation in the hepatic tissue. Treatment with garlic extract may contribute to significant amelioration in the hepatic steatosis and peroxidation processes.

Cardioprotective roles of aged garlic extract, grape seed proanthocyanidin, and hazelnut on doxorubicin-induced cardiotoxicity.

Doxorubicin (DXR) is a chemotherapeutic agent used effectively in the treatment of several childhood malignancies. During treatment, cardiotoxicity caused by cell damage due to the free oxygen radicals that are generated is a major limiting factor. This study was undertaken to determine whether DXR-induced cardiotoxicity could be prevented by natural foods with antioxidant properties such as aged garlic extract (AGEX), grape seed proanthocyanidin (PA), and hazelnut. Wistar albino male rats were assigned randomly to 9 groups each consisting of 15 rats. AGEX, PA, and hazelnut groups received these antioxidants in addition to their standard rat diet. They were also treated with cumulative intraperitoneal (i.p.) injections according to 2 different regimens: either a high-dose of 15 mg/kg DXR (3.75 mg/kg per week for 4 weeks) or a low-dose of 7.5 mg/kg DXR (1.875 mg/kg per week for 4 weeks). The control group received i.p. 0.9% saline. AGEX, PA, or hazelnut supplements were given orally to the groups for a 6-week period starting 1 week before the DXR treatment and ending 1 week after the treatment. One week after the last DXR injection, heart tissue samples were analyzed to determine malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and xanthine oxidase (XO) levels, and serum samples were taken for creatine kinase (CK). There were no significant changes in MDA levels among the control, DXR-treated groups, or supplemented groups that received additional natural antioxidant foods. SOD enzyme levels were decreased in rats treated with DXR. PA prevented the decrease at low doses of DXR. DXR treatment decreased CAT enzyme levels, but additional PA and hazelnut consumption increased these levels at low cumulative doses. XO enzyme levels were decreased in AGEX and hazelnut groups, but PA prevented the decrease. CK levels were elevated after DXR administration, indicating myocardial injury, but PA significantly reversed this. Although there were no differences histopathologically between AGEX, PA, and hazelnut groups, the protective effects of AGEX and PA were evident in electron microscopy. In conclusion, the positive effects of natural antioxidant foods on the prevention of DXR-induced cardiac injury could not be clearly shown on the basis of antioxidant enzymes. However, the electron microscopic changes clearly demonstrated the protective effects of AGEX and PA. The supplementation of these antioxidant foods over longer periods may show more definitive results. Human studies with different doses are needed to evaluate the effects of these foods on the human heart.

Oxidant stress due to non ionic low osmolar contrast medium in rat kidney.

BACKGROUND & OBJECTIVES: Contrast media may cause contrast-induced nephropathy (CIN) in risk group. This study was taken up to establish possible effects of non ionic low osmolar contrast medium administration on oxidant/antioxidant status and nitric oxide (NO) levels in rat kidney tissues. METHODS: Fourteen female, 14 wk old Wistar-albino rats were divided into 2 groups of 7 rats each (control and contrast groups). Non ionic low osmolar contrast medium was administered iv to the animals in the contrast group. The day after, animals were sacrificed and malondialdehyde (MDA) and NO levels and activities of antioxidant [superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT)] and oxidant [xanthine oxidase (XO)] enzymes were measured in kidney tissues. Serum creatinine levels were measured to evaluate kidney functions. RESULTS: Contrast medium administration caused an increase in MDA levels and a decrease in NO levels in kidney tissues. INTERPRETATION & CONCLUSIONS: The results suggest that non ionic low osmolar contrast medium administration leads to accelerated oxidant reactions and decreased NO level in rat kidney tissues. Further studies need to be done to assess the role of these changes in CIN.

Plasma paraoxonase activity in patients with systemic sclerosis.

BACKGROUND & OBJECTIVE: Systemic sclerosis (SSc) is a connective tissue disease characterized vascular damage and fibrosis. The aim of this study was to investigate the possible relation between systemic sclerosis and paraoxonase which is an antioxidant enzyme on the HDL. METHODS: Twenty nine patients with SSc and 16 healthy subjects (control group) participated in the study. Plasma cholesterol levels, anti-centromere antibody (ACA) levels and paraoxonase (PON) activities were measured. RESULTS: Lower level of high-density lipoprotein (HDL) cholesterol was observed in ACA negative SSc patients than in controls. Paraoxonase activity in ACA positive patients was however found to increase relative to control and ACA negative patient groups. INTERPRETATION & CONCLUSION: Our findings suggested that low HDL level in ACA negative SSc patients might be one of the factors leading to some vascular problems, and increased PON activity in ACA positive SSc group might have some role in the limitation of cutaneous sclerotic process observed in these patients. However, these preliminary findings need to be confirmed with a larger sample.

The role of oxidative mechanisms in the etiopathogenesis of pterygium: a preliminary study.

BACKGROUND: To evaluate the role of light-induced oxidative mechanisms in the pathogenesis of primary pterygium. METHODS: Pterygium specimens were obtained from 18 eyes of 18 patients undergoing pterygial removal (group A), and normal conjunctival specimens were obtained from 18 eyes of 18 patients undergoing cataract surgery (group B). In all specimens, malondialdehyde (MDA) levels, superoxide dismutase (SOD) and catalase (CAT) activities were studied and compared. RESULTS: In group A, the mean SOD activity was lower, and the mean MDA level was higher when compared to group B. However, these differences did not reach clinical significance (p > 0.05). On the other hand, the mean CAT activity was statistically significantly higher in group A when compared to controls (p = 0.017). CONCLUSION: This preliminary study indicates that oxidative mechanisms seem to play a role in the pathogenesis of pterygium. These mechanisms are apparently activated by ultraviolet irradiation. Further studies are required to establish the role of oxidative mechanisms in the pathogenesis of primary or recurrent pterygia.

Different effects of heating and freezing treatments on the antioxidant properties of broccoli, cauliflower, garlic and onion. An experimental in vitro study.

BACKGROUND: Vegetables have some beneficial effects on human health due to their antioxidant compounds, like polyphenols. Cooking leads to many physical and chemical changes to plant structure that can alter the phytochemical compounds of vegetables. OBJECTIVES: To investigate the effects of heat treatment and freezing on the antioxidant properties of garlic, onion, broccoli and cauliflower. DESIGN AND SETTING: Experimental in vitro study in a university laboratory. METHODS: Fresh broccoli (Brassica oleracea var. italica), cauliflower (Brassica oleracea var. botrytis), garlic (Allium sativum) and onion (Allium cepa) were obtained from a local store. These vegetables were divided into three treatment groups: raw, heated and frozen. The heat treatment consisted of heating them in a drying oven at 150 °C for 20 minutes. The freezing treatment consisted of keeping them frozen at -20 °C until analysis. The total phenolic content, antioxidant activity and malondialdehyde levels of the vegetables were measured using the Folin-Ciocalteu phenol reagent, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and thiobarbituric acid reactive substances, respectively. RESULTS: Heat treatment had deleterious effects on the antioxidant properties of onion and garlic; and it decreased the antioxidant activity of broccoli. Freezing improved the antioxidant activity of broccoli and garlic, but had detrimental effects for cauliflower and onion. CONCLUSIONS: Heat treatment and freezing exhibit different effects on the antioxidant properties of broccoli, cauliflower, garlic and onion. Convenient cooking and storage patterns should be identified for each vegetable, to obtain the best nutritional benefit from the antioxidant compounds of vegetables.

Honey prevents hepatic damage induced by obstruction of the common bile duct.

AIM: To examine the possible effects of honey supplementation on hepatic damage due to obstruction of the common bile duct in an experimental rat model. METHODS: The study was performed with 30 male rats divided into three groups: a sham group, an obstructive jaundice group, and an obstructive jaundice plus honey group. At the end of the study period, the animals were sacrificed, and levels of nitric oxide (NO), and NO synthase (NOS) activities were measured in liver tissues, and levels of adenosine deaminase (ADA) and alanine transaminase (ALT) activities were measured in serum. RESULTS: Blood ALT and ADA activities were significantly elevated in the jaundice group as compared to those of the sham group. In the obstructive jaundice plus honey group, blood ALT and ADA activities were significantly decreased as compared to those of the jaundice group. In erythrocytes and liver tissues, NO levels were found to be significantly higher in the obstructive jaundice plus honey group compared to those of the sham group. Additionally, NO levels were found to be significantly higher in liver tissues from the animals in the obstructive jaundice plus honey group than those of the jaundice group. CONCLUSION: Honey was found to be beneficial in the prevention of hepatic damage due to obstruction of the common bile duct.

Effects of garlic consumption on plasma and erythrocyte antioxidant parameters in elderly subjects.

BACKGROUND: The oxidative stress theory of aging is one of the most widely acknowledged theories of aging. The intake of fruits and vegetables with antioxidant power is associated with a reduced incidence of many chronic diseases of aging. OBJECTIVE: The effects of ingesting garlic on plasma and erythrocyte antioxidant parameters of elderly subjects were investigated in this study. METHODS: 13 subjects (mean age 70.69 +/- 4.23) participated in the study. They ingested garlic at the daily dose of 0.1 g/kg b.w. for 1 month. Before and after this period, fasting blood samples were obtained, and oxidant [malondialdehyde (MDA) and xanthine oxidase (XO)] and antioxidant [superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT)] parameters were studied in erythrocytes, and MDA levels were studied in plasma samples obtained from the subjects. Routine blood biochemical parameters were also measured in blood samples. RESULTS: In the plasma fraction and erythrocyte hemolysate, MDA levels were found to be significantly lower, but erythrocyte GSH-Px and SOD activities were significantly higher in the second samples relative to the first ones. XO activity was found to be lower in the second samples, but this decrease was not statistically meaningful. LDL cholesterol was found to be significantly lower in the second samples relative to the first ones. CONCLUSION: Our results show that ingestion of garlic leads to significantly lowered plasma and erythrocyte MDA levels and to increased activities of some antioxidant enzymes, which indicates that consumption of garlic decreases oxidation reactions. It is quite possible that reduced peroxidation processes due to garlic consumption may play a part in some of the beneficial effects of garlic in elderly subjects.

Activities of xanthine oxidase and superoxide dismutase enzymes in rat intestinal tissues in sepsis.

BACKGROUND: The aim of this study was to elucidate a possible source of oxidant stress in experimental sepsis. METHODS: For this aim, 32 Sprague-Dawley type rats were used in the study. After all the animals underwent laparotomy, nonlethal cecum ligation and puncture (CLP) technique was used to create an experimental sepsis model in two groups (CLP-6 and CLP-48 groups). Rats in the other groups (Sham operated) were used as controls. Animals in the control-6 and CLP-6 groups were killed 6 hours after the beginning of the study whereas the other animals were killed 48 hours after the beginning. Part of the terminal ileum of each animal was removed to be used in the measurements of xanthine oxidase and superoxide dismutase enzyme activities. RESULTS: Xanthine oxidase activity in the CLP-48 group was found to increase significantly as compared with that of the control-48 group, but superoxide dismutase activity did not change. No significant changes, however, were observed between analysis parameters in the terminal ileum tissues when obtained 6 hours after the beginning of sepsis. CONCLUSION: Our results suggest that increased xanthine oxidase activity is one of the leading factors for the oxidant stress in the late phase of sepsis.

Effects of aqueous green tea extract on activities of DNA turn-over enzymes in cancerous and non-cancerous human gastric and colon tissues.

AIM: The purpose of this study was to investigate possible effects of green tea extract on the activities of DNA turn-over enzymes, namely adenosine deaminase (ADA) and xanthine oxidase (XO) in gastric and colon tissues from patients with stomach and colon cancer. MATERIALS AND METHODS: Six cancerous and 6 non-cancerous adjacent human gastric tissues, and 7 cancerous and 7 non-cancerous adjacent colon tissues obtained surgically were treated with aqueous green tea extract at 3 different concentrations for 1 hour, and then ADA and XO activities were measured. RESULTS: In all of the tissues, XO activities were found to elevate after treatment with green tea extract. Additionally, ADA activity was found to be inhibited in the cancerous gastric tissues by the green tea extract. Elevated XO and reduced ADA activities due to treatment with green tea extract may lower salvage pathway activity and lead to inhibition in carcinogenesis. CONCLUSION: Our data suggest that green tea may support the medical treatment of stomach and colon cancer.

Ionic high-osmolar contrast medium causes oxidant stress in kidney tissue: partial protective role of ascorbic acid.

It has been known that contrast medium may cause contrast-induced nephropathy in risk groups. This study sought to establish possible effects of ionic high-osmolar contrast medium administration with or without antecedent cisplatin treatment on oxidant/antioxidant status in rat kidney tissues, as well as to investigate a possible protective role of antioxidant ascorbic acid in this regard. Thirty-five female, 14-week-old Wistar-albino rats were used in this study. They were divided into five groups of seven rats (sham, contrast, contrast + ascorbic acid, contrast + cisplatin, and contrast + cisplatin + ascorbic acid). Ascorbic acid was given in a dose of 250 mg/kg/day orally throughout the study period, and cisplatin (10 mg/kg) as a single i.v. dose on the fourth day. Ionic high-osmolar contrast medium (3 gr/kg iodine as a single dose) was administered by i.v. route on the fifth day. After the animals were sacrificed on the sixth day, their kidney tissues were removed surgically to be used in the analyses. Malondialdehyde (MDA) level and activities of antioxidant (superoxide dismutase [SOD], glutathione peroxidase [GSH-Px] and catalase [CAT]) and oxidant (xanthine oxidase [XO]) enzymes were measured in these samples. Serum urea and creatinine levels were measured to evaluate kidney functions. Histopathological investigation of the tissues was also performed. It was observed that contrast medium administration caused increases in MDA levels in the kidney tissues, either alone or together with antecedent cisplatin treatment. However, ascorbic acid prevented the increases in MDA levels in the kidney tissues. Histopathological findings revealed that ionic high-osmolar contrast medium administration alone led to mild acute structural damage, but contrast medium administration together with antecedent cisplatin usage caused severe tubular necrosis. Ascorbic acid supplementation prevented these changes, to a great extent. The results suggest that ionic high-osmolar contrast medium administration, either alone or together with antecedent cisplatin treatment, leads to accelerated oxidative reactions in rat kidney tissues, and ascorbic acid protects in part the kidney tissues against this oxidant stress.