Lower Glutathione Peroxidase Activity Research Articles

Ameliorative effect of protein and calcium on fluoride-induced hepatotoxicity in rabbits

To investigate whether protein (Pr) or calcium (Ca) supplementation could ameliorate hepatic damage induced by excessive fluoride (F); thirty-two 30-day-old healthy New Zealand rabbits were randomly divided into four groups (female: male = 1:1). The four groups were maintained on distilled water and fed the following diets for 120 days: (1) a malnutrition control (MC) diet (8.58% Pr, 0.49% Ca); (2) the MC diet plus HiF (high fluoride in their diet, 200 mg F ion/kg from NaF); (3) a Ca deficient MC diet plus HiPr+HiF (0.46% Ca, 18.41% Pr, plus HiF); and (4) a Pr deficient MC diet plus HiCa+HiF (2.23% Ca, 8.35% Pr, plus HiF). Results show that in HiF group, the serum total Pr (TPr) and albumin (ALB) content significantly decreased, whereas both Pr and Ca rich diets significantly enhanced their levels. In liver, low superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, high malondialdehyde (MDA) content, and evident mitochondria lesions in HiF group indicated a significant oxidative stress, while Pr or Ca supplementation brought an ultrastructural repair and a recovery antioxidant defense in liver. The findings in the present work implied the ameliorative effects of Pr or Ca supplementation on F-induced hepatotoxicity in rabbits. Keywords: Fluoride, hepatotoxicity, malnutrition, calcium supplementation, protein supplementation

Nitric Oxide and Antioxidant Enzymes in Venous and Cord Blood of Late Preterm and Term Omani Mothers

This study assessed the role of oxidative stress in parturition in Omani mothers following growing reports that late preterm neonates were at greater risk than term neonates of perinatal death. Venous blood samples were collected during labour, and cord (neonatal) blood samples were taken after childbirth in late preterm and term from women at Sultan Qaboos University Hospital, Oman. Plasma nitric oxide (NO) concentrations, erythrocyte catalase (CAT). Erythrocyte glutathione peroxidase (GPx) activities were measured using spectrophotometric methods. When compared with term mothers, late preterm mothers had markedly higher NO concentrations (μmol/L) 17.1 ± 3.3 versus 11.0 ± 5.5 (P <0.0001), and lower GPx values (U/g Hb) 94.1 ± 12.9 versus 110.4 ± 12.3 (P <0.0001). Late preterm mothers were significantly younger (P = 0.027) than term mothers and had neonates that weighed significantly less (P <0.0001) than term neonates. GPx activity was significantly reduced (P = 0.001) in late preterm neonates as compared to term neonates. CAT showed no change in activity in any comparison. Distinctly higher values of NO and lower GPx activity were found in late preterm mothers relative to term mothers; also, lower GPx in late preterm neonates relative to term neonates suggested a pro-oxidant-antioxidant imbalance due to the greater oxidative burden in late preterm parturition.

Protective role of glutathione reductase in paraquat induced neurotoxicity

Paraquat (PQ), a widely used herbicide is a well-known free radical producing agent. The mechanistic pathways of PQ neurotoxicity were examined by assessing oxidative/nitrosative stress markers. Focus was on the role of glutathione (GSH) cycle and to examine whether the pre-treatment with enzyme glutathione reductase (GR) could protect the vulnerable brain regions (VBRs) against harmful oxidative effect of PQ. The study was conducted on Wistar rats, randomly divided in five groups: intact-control group, (n=8) and four experimental groups (n=24). All tested compounds were administered intrastriatally (i.s.) in one single dose. The following parameters of oxidative status were measured in the striatum, hippocampus and cortex, at 30min, 24h and 7days post treatment: superoxide anion radical (O2−), nitrate (NO3−), malondialdehyde (MDA), superoxide dismutase (SOD), total GSH (tGSH) and its oxidized, disulfide form (GSSG) and glutathione peroxidase (GPx).Results obtained from the intact and the sham operated groups were not statistically different, confirming that invasive i.s. route of administration would not influence the reliability of results. Also, similar pattern of changes were observed between ipsi- and contra- lateral side of examined VBRs, indicating rapid spatial spreading of oxidative stress. Mortality of the animals (10%), within 24h, along with symptoms of Parkinsonism, after awakening from anesthesia for 2–3h, were observed in the PQ group, only. Increased levels of O2−, NO3− and MDA, increased ratio of GSSG/GSH and considerably high activity of GPx were measured at 30min after the treatment. Cytotoxic effect of PQ was documented by drastic drop of all measured parameters and extremely high peak of the ratio GSSG/GSH at 24th hrs after the PQ i.s. injection. In the GR+PQ group, markedly low activity of GPx and low content of NO3− (in striatum and cortex) were measured during whole experiment, while increase value was observed only for O2−, at 7th days.We concluded that oxidative/nitrosative stress and excitotoxicity are the most important events since the early stage of PQ induced neurotoxicity. Based on the ratio GSSG/GSH, the oxidation of GSH to GSSG is probably dominant way of GHS depletion and main reason for reduced antioxidative defense against PQ harmful oxidative effect. The GR pre-treatment resulted in the absence of Parkinson’s disease-like symptoms and mortality of the rats. Additionally, oxidative/nitrosative stress did not developed, as well as almost diminished metabolism of the VBRs at 24th hours (as has been documented in the PQ group) did not occurred in the GR+PQ, suggesting a neuroprotective role for the GR in PQ induced neurotoxicity.

Low Serum Glutathione Peroxidase Activity Is Associated with Increased Cardiovascular Mortality in Individuals with Low HDLc’s

BackgroundSince oxidized LDL is thought to initiate atherosclerosis and the serum glutathione peroxidase (GPx3) reduces oxidized lipids, we investigated whether high GPx3 activity reduces cardiovascular disease (CVD) mortality.MethodsWe determined GPx3 in stored samples from the Minnesota Heart Survey of 130 participants who after 5 to 12 years of follow-up had died of CVD and 240 controls. Participants were 26 to 85 years old and predominantly white. In a nested case-control, study we performed logistic regressions to calculate odds ratios (OR) adjusted for age, sex, baseline year, body mass index, smoking, alcohol intake, physical activity, total and HDL cholesterols, systolic blood pressure, serum glucose and gamma glutamyltransferase (GTT) activity. The referent was the quartile with the highest GPx3 activity (quartile 4).ResultsOR’s for CVD mortality for increasing quartiles of GPx3 were 2.37, 2.14, 1.83 and 1.00 (P for trend 0.02). This inverse correlation was confined to those with HDLc’s below the median (P for interaction, 0.006). The OR’s for increasing quartiles of GPx3 in this group were 6.08, 5.00, 3.64 and 1.00 (P for trend, 0.002).ConclusionsIndividuals with both low HDLc and GPx3 activity are at markedly increased risk for death from CVD.

Antioxidation status and histidine dipeptides content in broiler blood and muscles depending on protein sources in feed

One-day-old chickens were fed mixtures containing different raw materials (fish by-products meal, porcine blood cells meal, blood meal, wheat gluten, fodder yeast), as a source of histidine and β-alanine - components of carnosine. Control birds were administered a feed mixture, in which soy bean meal was the main protein source. The bodyweight, feed consumption and conversion, antioxidant characteristics and histidine dipeptides content in blood and muscles, and also amino acid composition of chicken meat on day 34 post-hatch were recorded. The best (p < 0.05) performance and feed conversion were observed in chickens fed mixture containing porcine blood cells meal. In blood plasma of control chickens, a significantly (p < 0.01) higher ability to scavenge DPPH radicals was found. However, the highest catalase activity in erythrocytes was determined in chickens fed mixtures with blood by-products. Insignificant differences in both carnosine and anserine levels in plasma between treatments were noted. Breast muscles from control birds were characterized by lower activity of glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) (p < 0.05; p < 0.01), than those from chickens fed blood by-products. Improved ability to reduce ferric ions (FRAP) (p < 0.01) and carnosine content in meat from chickens fed blood cell meal were recorded. No direct relations between amino acids content in feed mixtures and in meat were observed.

Prostate Disease Risk Factors among a New Zealand Cohort

Background: Prostate cancer is a leading public health burden worldwide, and in New Zealand it is the most commonly registered cancer and the third leading cause of cancer deaths among males. Genetic variability and its associations with diet, demographic and lifestyle factors could influence the risk of this disease. Methods: The single nucleotide polymorphisms (SNPs) within a group of antioxidant genes and related markers were tested between patient and control cohorts, adjusted for significant differences between basic lifestyle and demographic characteristics. Results: Increasing age, smoking and low serum selenium levels were significantly associated with an increased risk for prostate disease. Alcohol consumption increased the glutathione peroxidase (GPx) activity. A significant reduction in alcohol consumption was recorded with prostate disease. Three SNPs, namely GPx1 rs1050450, SEL15 rs5845 and CAT rs1001179, were significantly associated with prostate disease risk. A cumulative risk of prostate cancer was noted with 6 risk alleles. A lower GPx activity was recorded with prostate disease compared to the controls. However, the GPx1 rs1050450 allele T in association with prostate cancer recorded a significantly higher GPx activity compared to the controls. Conclusions: These data point to a possibility of identifying individuals at risk of prostate cancer for better management purposes.

Influence of sex and glucocorticoid exposure on preterm placental pro-oxidant-antioxidant balance

Glucocorticoids (GC) are known to influence fetal ROS production and anti-oxidant defences yet little attention has focused on the potential for effects in the placenta. We hypothesised that antenatal GC exposure alters placental pro-oxidant-anti-oxidant balance sex-specifically, based upon the known relationship between male sex and poor pregnancy outcome. Placentae were collected from 60 women who delivered between 24 and 31 completed weeks gestation and placental oxidative and nitrative stress (protein carbonyl, lipid hydroperoxide, and nitrotyrosine concentration) and anti-oxidant enzyme activity (glutathione peroxidase, thioredoxin reductase, and superoxide dismutase) measured. A pro-oxidant state was observed in placentae of male compared to female infants born within 72 h of antenatal GC exposure, with higher levels of protein carbonyl content (p = 0.04), lipid hydroperoxide (p < 0.01) and nitrotyrosine content (p = 0.02), and lower levels of glutathione peroxidase activity (p = 0.01). A pro-oxidant state continued to be observed in placentae of males compared to females born outside of 72 h, with higher protein carbonyl content (p = 0.04) and lower glutathione peroxidase activity (p = 0.01) than females, however no differences in placental lipid hydroperoxide and nitrotyrosine content were observed. These sex-specific alterations in products of placental oxidative stress could not purely be explained by differences in clinical illness severity (CRIB2 score). Therefore, these sex-specific alterations in placental pro-oxidant-antioxidant balance in response to antenatal betamethasone exposure, independent of illness severity, could contribute to the patho-physiologic processes underlying oxygen radical diseases of the newborn, conditions known to exhibit a male excess.

Anti‐ageing effects of protocatechuic acid from Alpinia on spleen and liver antioxidative system of senescent mice

The effects of Alpinia protocatechuic acid (PCA) on spleen and liver antioxidant system in aged rats have been studied. Alpinia PCA, a phenolic compound, was first isolated from the dried fruits of Alpinia Oxyphylla Miq. in our laboratory. Young and aged rats were injected intraperitoneally with Alpinia PCA at single doses of 5 mg kg(-1) (low dose) or 10 mg kg(-1) (high dose) per day for 7 days. The activities of endogenous antioxidants and the content of lipid peroxide in spleen and liver were assayed. Compared with young group, aged rats had significantly lower splenic weights, lower activities of glutathione peroxidase (GSH-PX) and catalase (CAT), higher level of malondialdehyde (MDA) in spleen and liver. The results proved that Alpinia PCA significantly elevated the splenic weights, increased the activities of GSH-PX and CAT and decreased the MDA level of aged rats. All these suggested that Alpinia PCA was a potential anti-ageing agent, and its effects on spleen and liver were achieved at least partly by promoting endogenous antioxidant enzymatic activities and normalizing age-associated alterations. It may be therapeutically useful to minimize age-associated disorders where oxidative damage is the major cause.

Oxidative stress in the pathogenesis of neurodegenerative diseases

Oxidative stress is a deleterious condition leading to neuronal cell death. The brain is particularly vulnerable to damage mediated by reactive oxygen and reactive nitrogen species, due to their high concentrations of unsaturated fatty acids, high rate of oxygen consumption, high content of metals catalyzing free radical formation. And finally, the brain is relatively deficient in antioxidant systems with lower activity of glutathione peroxidase and catalase compared to other organs. There is a lot of evidence indicating that oxidative stress plays crucial role in aging as well as in the development and pathology of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. A number of ageing-related neurodegenerative diseases are associated with impaired mitochondrial function, increased oxidative damage, presence of abnormal, aggregated proteins, iron dyshomeostasis, and involvement of excitotoxicity and inflammation. Neurodegenerative disorders are characterized by an abnormal accumulation of oxidatively damaged macromolecules inside the cells and in the extracellular space. The abnormal production by overactivated glial cells of pro-inflammatory cytokines, chemokines and the complement system, as well as reactive oxygen species, can disrupt nerve terminals activity and cause dysfunction and loss of synapses, which correlates with memory decline. This review discusses current knowledge about the involvement of oxidative stress in neurodegenerative diseases pathogenesis, focusing on impaired mitochondrial function, oxidative damage, presence of abnormal, aggregated proteins, iron dyshomeostasis, and functional responses of microglia.

Antioxidant enzymes in erythrocytes from hypertension patients receiving lisinopril monotherapy or combined lisinopril plus simvastatin therapy

Statins and angiotensin-converting enzyme (ACE) inhibitors have beneficial impact on the serum cholesterol and blood pressure. It is supposed that statins and ACE inhibitors may modify the antioxidative status of erythrocytes. The study objective was to compare the effects of two treatments, lisinopril alone vs lisinopril plus simvastatin, on erythrocyte antioxidant enzyme activities. The study involved 32 patients with arterial hypertension, the initial serum total cholesterol, LDL-cholesterol and triglycerides within the normal range. Patients of two groups, each of 16 subjects, were treated with lisinopril (10 mg/day) or with lisinopril (10 mg/day) plus simvastatin (20 mg/day). Before and after 3 and 6 months of follow-up therapy, activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), glutathione reductase (GLR) in purified erythrocytes were determined. In all patients, significantly higher catalase activity (by 79.3-106.5%, p < 0.0001) and significantly lower GPx activity (by 20.7-30.6%, p < 0.001) were observed after therapy as compared to the baselines. Just the same results were obtained in both groups (lisinopril and lisinopril + simvastatin), after both periods (3 and 6 month) of treatments. SOD activity was increased only in the lisinopril group and only after 6 months (p = 0.0345). No changes of GLR reductase activity were seen under all conditions indicated. Thus, the lisinopril monotherapy and combined lisinopril plus simvastatin therapy exhibit specific, pronounced and equipotent effects on antioxidant enzymes in human erythrocytes. Administration of lisinopril or lisinopril plus simvastatin may protect erythrocytes and other tissues from oxidative damage.

Vitamins B status and antioxidative defense in patients with chronic hepatitis B or hepatitis C virus infection

The impact of hepatitis B virus (HBV) or hepatitis C virus (HCV) infection upon B vitamins status and antioxidative defense in infected patients was examined. Dietary record and blood levels of B vitamins and oxidative stress-associated biomarkers were determined for 195 healthy controls, 132 HBV, and 114 HCV patients. HBV-infected patients had significantly higher levels of total cholesterol, free fatty acids (FFA), and lower ghrelin level (p < 0.05); and HCV-infected patients had significantly higher Ishak inflammation score and lactate dehydrogenase activity (p < 0.05). HBV patients had significantly lower red blood cell (RBC) vitamins B(2) and B(6) levels, and HCV infection significantly decreased vitamins B(2,) B(6) and folate levels in RBC and/or plasma (p < 0.05). Correlation coefficients of RBC vitamin B(2) versus serum FFA in HBV patients, RBC vitamins B(2) and B(6) versus HCV RNA and Ishak inflammation score, and plasma vitamin B(6) vs Ishak inflammation score in HCV patients were <-0.5. HBV-infected patients had significantly higher oxidized glutathione level and lower glutathione peroxidase activity (p < 0.05), but HCV patients had significantly lower superoxide dismutase and catalase activities (p < 0.05). HBV or HCV infection enhanced oxidative stress and lowered B vitamins in circulation. In order to avoid other healthy risk, nutrition status should be monitored and limitation or supplementation of certain nutrients might be helpful for HBV- or HCV-infected patients.

Erythrocyte antioxidant enzymes in hypertensive patients receiving lisinopril monotherapy or combined lisinopril plus simvastatin therapy

Statins and angiotensin-converting enzyme (ACE) inhibitors have beneficial impact on the serum cholesterol and blood pressure. It is supposed that statins and ACE inhibitors may modify the antioxidative status in erythrocytes. The study objective was to compare the effects of two treatments, lisinopril alone versus lisinopril plus simvastatin, on erythrocyte antioxidant enzyme activities. The study involved 32 patients with arterial hypertension, their initial serum total cholesterol, LDL-cholesterol and triglycerides were within the normal range. Patients of two groups, each of 16 subjects, were treated with lisinopril (10 mg/day) or with lisinopril (10 mg/day) plus simvastatin (20 mg/day). Before and after the ambulatory therapy for 3 and 6 months, activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), glutathione reductase (GR) were determined in purified erythrocytes. All treated patients had significantly higher catalase activity (by 79.3–106.5%, p < 0.0001) and significantly lower GPx activity (by 20.7–30.6%, p < 0.001) as compared to the baselines. The same results were obtained in both groups (lisinopril and lisinopril + simvastatin), after both periods (3 and 6 month) of treatments. SOD activity increased only in the lisinopril group and only after 6 months (p = 0.0345). No changes of GR activity were observed under all conditions studied. Thus, the lisinopril monotherapy and combined lisinopril plus simvastatin therapy exhibit specific, pronounced and equipotent effects on antioxidant enzymes in human erythrocytes. Peroral administration of lisinopril or lisinopril plus simvastatin may protect erythrocytes and other tissues against oxidative damage.

High perioperative level of oxidative stress as a prognostic tool for identifying patients with a high risk of recurrence of head and neck squamous cell carcinoma

The aim of the study was to investigate the relationships among (a) glutathione peroxidase (GPx) and malondialdehyde (MDA); (b) oncological characteristics (i.e., TNM classification, tumor grade), and; (c) prognosis of head and neck squamous cell carcinoma. In a prospective cohort study, we followed 88 patients for 67.4 months (median 40.3) after surgery for head and neck squamous cell carcinoma. Activity of GPx was determined by ELISA and plasma MDA concentration by liquid chromatography. Lower GPx activity was observed in the T3/4 patients than in the T1/2 group. Tumor grade was significantly correlated with both GPx (P = 0.001) and MDA (P = 0.05, both Spearman). The perioperative level of MDA was higher in patients who later recurred during the follow-up period (n = 15) than in the complete remission group (P = 0.01, Mann-Whitney). Median disease-free interval and overall survival in the group with MDA > median were 29.5 and 32.0 months, respectively, and 38.4 and 40.3 months in the patient group with MDA ≤ median (P = 0.10 and P = 0.08, respectively; Kaplan-Meier). Patients with MDA levels higher than the median had a more than twofold greater risk of recurrence than patients with MDA levels smaller than the median (31.3 vs. 15.2%, P = 0.06, logrank). Our results suggest that an increased MDA level at the time of initial surgery is found in patients with a high risk of recurrence, which suggests that each patient can be categorized according to risk of recurrence based on their MDA level at the time of initial surgery.

Selenium and Hormone Interactions in Female Patients with Hashimoto Disease and Healthy Subjects

Objective. To examine the correlation structure of parameters expressing selenium status, sex hormones secretion and thyroid function in a group of patients with Hashimoto disease and healthy female subjects. Method. Partial Least Square modeling was applied to parameters under study. Results. The correlations between relevant parameters were confirmed. Selenoenzyme glutathione peroxidase (GPX3) an progesterone played the most significant roles among factors contributing to thyroid stimulating hormone and free thyroxine regulation. Additionally, a correlation between GPX3 and estradiol was also observed which is in agreement with results reported by other authors. Patients with Hashimoto disease had lower glutathione peroxidase activities than healthy subjects. Conclusion. The integrated multivariate approach applied to a new group of patients dissimilar to the previous one, was validated by statistical adequacy as well ass meaningful interpretation.

Specific and Pronounced Impacts of Lisinopril and Lisinopril Plus Simvastatin on Erythrocyte Antioxidant Enzymes

Angiotensin-converting enzyme inhibitors are effective at reducing blood pressure, whereas statins decrease plasma cholesterol impeding atherosclerosis. It is hypothesized that these medications may improve blood pressure and serum cholesterol by modifying the antioxidative status and energy metabolism of erythrocytes. In this study, the effects of 2 treatments are compared: lisinopril alone versus lisinopril + simvastatin, on erythrocyte antioxidant and energy metabolic enzymes. Patients with atherosclerosis and moderate hypertension are randomly assigned to receive lisinopril 10 to 20 mg/d or lisinopril 10 to 20 mg/d plus simvastatin 20 mg/d for 24 weeks. Higher catalase activity and lower glutathione peroxidase activity are observed in 94% to 100% patients from both groups after 12 and 24 weeks of treatment. Superoxide dismutase activity is increased significantly only after 24 weeks. No changes of glutathione reductase, lactate dehydrogenase, and phosphofructokinase activities are found under any conditions indicated. Both treatments decrease systolic and diastolic blood pressure equally. Only lisinopril + simvastatin treatment decreases plasma total cholesterol and low-density lipoprotein cholesterol. The results show for the first time that lisinopril monotherapy and combined lisinopril + simvastatin therapy exhibit specific and pronounced effects on antioxidant and energy metabolic enzyme activities in erythrocytes of hypertensive patients.

Blood selenium, glutathione peroxidase activity and antioxidant supplementation of subjects exposed to arsenic via drinking water

This work investigated serum selenium (Se) and glutathione peroxidase (GPx) levels in 25 Croatian subjects exposed to high levels of As from drinking water (median As level in urine: 620.74 μg/g creatinine) and 25 controls (32.98 μg/g creatinine). The exposed group had lower ( p < 0.001) median serum Se and GPx levels (Se: 82.34 μg/l vs 59.02 μg/l; GPx: 45.99 U/g hemoglobin vs 38.38 U/g hemoglobin). A subsample of 20 exposed subjects took part in a 2-month antioxidant supplementation trial which increased median GPx activity from 30.71 to 40.98 U/g hemoglobin ( p = 0.041) and reduced total urinary As median from 680.15 to 501.96 μg/g creatinine ( p = 0.051). The effect of selected catalase (−262C>T) and GPx1 (−593C>T) gene polymorphisms was also examined. The low Se status and GPx activity may heighten risk of adverse health effects, especially in genetically predisposed individuals. The outcome of antioxidant treatment indicates modulation of As metabolism and oxidative stress, relevance of which needs further research.

Selenium in human nutrition in New Zealand.

New Zealand's soil has a low concentration of selenium (Se), and its residents have a lower Se status than do most other peoples. However, New Zealanders do not suffer from the Se-responsive ills that afflict their farm animals and some people in China. New Zealanders, particularly those in the South Island, may have adapted to their low Se environment by thriftiness in urinary excretion of Se. Low glutathione peroxidase activities in their tissues have not resulted in noticeable damage or changes. The enzyme activity can be raised to a plateau by Se supplements, but there is no evidence that supplementation leads to better health. Since patterns of coronary heart disease, hypertension, and cancer in New Zealand resemble those in other Western countries, no direct link between these diseases and Se level is likely.

The time-trend and the relation between smoking and circulating selenium concentrations in Norway

Objectives The objectives of this study were to investigate biomarkers of selenium status in relation to smoking habits and to analyze the time-trend of selenium in serum (S-Se) in Norway during the time period 1995–2006. Methods The impact of smoking habits was investigated in a population recruited to a cross-sectional study of blue-collar workers in the southern part of the country ( n=98). The time-trend was studied in all subjects who delivered blood samples for the determination of S-Se to a large commercial clinical chemistry laboratory in Norway. Results Smokers had 0.14 and 0.20 μmol/L lower concentrations of selenium in whole blood (B-Se) and serum, respectively, than non-smokers. The amount of smoking, as assessed by the serum cotinine concentration, was negatively associated with the B-Se concentration (Pearson's r=−0.43). The 1/3 of the blue-collar workers with the lowest concentrations of B-Se or S-Se had lower activity of glutathione peroxidase in serum (S-GSHpx) than the remaining subjects. Snuff users had about the same levels of B-Se and S-Se as the non-smokers, although they had about the same amount of nicotine metabolites in urine and serum as the smokers. A decreasing trend of S-Se was observed during the observation period from 1995 to 2006. The mean concentration was 1.26 μmol/L in 1995, while the lowest mean concentration was measured in 2003 (1.01 μmol/L). Conclusion Smoking, but not snuffing, is associated with lower concentrations of B-Se and S-Se. The reduction of B-Se is negatively associated with the nicotine biomarker cotinine in serum. A substantial proportion of blue-collar workers had not maximized the activity of S-GSHpx. Selenium status may have become poorer since 1995.

Effects of Folic Acid and Ascorbate Supplementation on Plasma Homocysteine and Oxidative Stress in Patients with Type 2 Diabetes Mellitus

In patients with type 2 diabetes, oxidative stress could be increased by their metabolic changes. Elevated plasma homocysteine is considered as one of markers of enhanced oxidative stress. Due to oxidative stress, some complications like cardiovascular or renal diseases may develop in type 2 diabetes patients. Plasma homocysteine concentration may be increased if folate status were inadequate. Protective effects against oxidative stress may be diminished if the status of anti-oxidative nutrient as vitamin C was poor. It is, therefore, important to maintain adequate status of folate and vitamin C in type 2 diabetes patients. Thus, this study was performed to determine the effects of supplementation of folate and/or ascorbate on blood glycated hemoglobin (HbA1c) level, serum concentrations of homocysteine and cholesterol, plasma oxidized low density-lipoprotein (LDL), concentration and plasma glutathione peroxidase (GSH-Px) activity in the patients with type 2 diabetes. A total of 92 type 2 diabetes patients participated voluntarily with written consents. They were divided into one of the four experimental groups; Control (C), Folate-supplemented (F), Ascorbate-supplemented (A), and Folate plus ascorbate-supplemented (FA). The subjects in C were taken placebo, those in F were supplemented 1 mg of folate, those in A received 1,000 mg of ascorbate, and those in FA were given 1 mg of folate plus 1,000 mg of ascorbate daily for 4 weeks. Supplementation of folate or ascorbate resulted to increase serum folate level or plasma ascorbate concentration apparently, respectively. Folate supplementation not ascorbate seemed to decrease plasma concentrations of homocysteine and oxidized LDL and reduce plasma GSH-Px activity. There might not be synergic effect of the supplementation of folate plus ascorbate. The results indicate that oxidative stress in the patients with type 2 diabetes may lower mainly by folate supplementation. (Korean J Nutr 2009; 42(2): 107 ~ 118)

State of antioxidative protection in central nervous ganglia of the mollusc Lymnaea stagnalis at modulation of activity of the NO-ergic system

In experiments on mollusc Lymnaea stagnalis, the state of antioxidative protection is studied in central nervous ganglia during a long-term activation (inhibition) of synthesis of nitrogen monoxide (NO) in the body. The effect of the blocker of NO-synthase NG-nitro-L-arginine (L-NNA) at the background of enhancement of pulmonary respiration has been found to be associated with a rise of levels of reduced glutathione and TBK-active products in the nervous tissue at preservation of a relatively high superoxide dismutase activity and a low glutathione peroxidase activity compared with the control group and the animals treated with the metabolic precursor of NO synthesis L-arginine. In spite of the revealed disturbances of balance of the body proand antioxidative system, DNA electrophoresis detected no products of its degradation, which can indicate the absence of massive programmed death of the nervous tissue cells in Lymnaea stagnalis during modulation of activity of the NO-ergic system.