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Objective: Oxidative stress plays a key role in the pathogenesis of male infertility. But, the adverse effects of oxidative biomarkers on sperm quality remain unclear. This study aimed to investigate the levels of nitric oxide (NO), 8-hydroxydesoxyguanosine (8-OHdG), and total antioxidant capacity (TAC) oxidative biomarkers in seminal plasma and their relationship with sperm parameters.Methods: A total of 77 volunteers participated in the study, including fertile (n=40) and infertile men (n=37). NO, 8-OHdG, and TAC levels were measured using the ferric reducing ability of plasma, Griess reagent method and an enzyme-linked immunosorbent assay kit, respectively.Results: The mean values of sperm parameters in the infertile group were significantly lower than those in the fertile group (pp=0.013) than those of controls, while the mean TAC was significantly lower (p=0.046). There was no significant difference in NO level between the two groups. The elevated seminal 8-OHdG levels were negatively correlated with semen volume, total sperm counts and morphology (pp=0.001 and p=0.052, respectively). NO levels were negatively correlated with semen volume, total sperm counts and morphology (p=0.014, p=0.020 and p=0.060, respectively). Positive correlations between TAC and both sperm count and morphology (p=0.043 and p=0.025, respectively) were also found.Conclusion: These results suggested that increased levels of NO and 8-OHdG in seminal plasma could have a negative effect on sperm function by inducing damage to the sperm DNA hence their fertility potentials. Therefore, these biomarkers can be useful in the diagnosis and treatment of male infertility.

8-Hydroxydeoxyguanosine (8-OHdG) is one of the main products of DNA oxidative stress injury and has been widely used for quantitative analyzing ROS levels. However, the intracellular detection of 8...

Gliomas are one of the most aggressive brain tumors with a poor prognosis in the central nervous system. Bexarotene is a third-generation retinoid X receptor agonist that is promising in the treatment of both cancer and neurodegenerative diseases. In this study, we aimed to investigate the cytotoxic and anti-proliferative effects of bexarotene in C6 glioma cells through the PPAR gamma/NF-kappa B pathway. In the study, first cytotoxic bexarotene concentrations for C6 cells were detected, and then apoptosis profile, reactive oxygen species (ROS), total antioxidant (TAS), 8-hydroxy-2 '-deoxyguanosine (8-OHdG) and nuclear factor-kappa B (NF-kappa B) levels in the cells were determined. In addition, peroxisome proliferator-activated receptor gamma (PPAR gamma) mRNA expression analysis was carried out. As a result, we detected concentration- and time-dependent antiproliferative effects of bexarotene on C6 cells. We found that bexarotene treatment decreased NF-kappa B and TAS levels and increased PPAR gamma and 8-OHdG levels in C6 cells. Bexarotene enhanced PPAR gamma expression in a dose-dependent manner when compared to the control group (P < 0.01). Furthermore, we determined that bexarotene-induced apoptotic C6 cells enhanced through Annexin V-FITC/PI staining and caspase-3/-7 activation analyses since phosphatidylserine level on the outer surface of the cell membrane and caspase-3/-7 activities were increased in the cells treated with bexarotene. In conclusion, bexarotene treatment in C6 glioma cells could modulate apoptosis profile, DNA damage, ROS production, and reduction of TAS levels through inhibition of NF-kappa B by enhancing PPAR gamma expression. WOS:000619456600001 2-s2.0-85101114648 PubMed: 33599853

Objective: The aim of this study is finding an optimal and convenient aging marker. Method: The information of participants’ occupation, family background, life style, physical condition, etc. was obtained by a self-administered questionnaire. Spot urine and saliva samples were collected during the early morning after fasting overnight. 8-hydroxydeoxygunaosine (8-OHdG), 8-iso-prostaglandin F2[Formula: see text] (8-isoPGF2[Formula: see text]), advanced oxidation protein products (AOPPs), malondialdehyde (MDA), and dehydroepian drosterone sulfate (DHEA-S) were measured by ELISA. Results: Around 112 non-smokers (males/females [Formula: see text] 61/51; mean age [Formula: see text] 44.9 years) were eligible and analyzed in this study. The mean urinary 8-OHdG level was [Formula: see text] (ng/mmol, creatinine) and mean 8-isoPGF2[Formula: see text] level was [Formula: see text] (pg/mmoL, creatinine). In saliva, the mean level of AOPPs, MDA, and DHEA-S was [Formula: see text] ([Formula: see text]mol/L), [Formula: see text] ([Formula: see text]mol/L) and [Formula: see text] (ng/mL), respectively. After analysis in multiple regression model, urinary 8-OHdG was influenced by age and tea consumption ([Formula: see text]); urinary 8-isoPGF2[Formula: see text] level was correlated with gender ([Formula: see text]); salivary DHEA-S was related to gender ([Formula: see text]) and marital status ([Formula: see text]); AOPPs and MDA in saliva presented no relationships with those factors. Conclusion: Among healthy non-smokers, urinary 8-OHdG is the best aging biomarker comparing to other markers.

In this study, the effect of Morus nigra (M. nigra) on carbon tetrachloride (CCI4)-induced hepatic injury in the rat was investigated. A hepatotoxic rat model was developed by the injection of CCI4 dissolved in soybean oil (1 mL/kg/twice a week, intraperitoneal (i.p.) injection). Following the formation of hepatic injury, extracts of M. nigra at doses ranging from 150 to 300 mg/kg were administered to rats by i.p. injection for eight weeks. At the end of administration, rat livers were excised by dissection. The activities of liver enzymes, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (GGT) were detected in the serum, and the activities of antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GPx), were established in the liver. Histological changes and immunohistochemical localization of caspase-3 and 8-oxo-2’-deoxyguanosine (8-OhdG) were performed by hematoxylin-eosin (H&E) staining of liver sections and caspase-3 and 8-OhdG immunohistochemical staining. The results showed that the M. nigra extract prevented protein oxidation generated by CCI4. The extracts demonstrated the ability to modulate the activity of SOD and GPx, and also prevented the CCI4-induced increase in AST and GGT levels. These results indicate that M. nigra extracts provided significant protection against CCl4-induced hepatic injury and might also present a novel approach for the treatment of some liver diseases.

Graphical abstract, Highlights • Nicotine decreased the antioxidant capacities in male rats. • The lung of nicotine-treated rats showed severe congestion of the alveolar lung tissues. • Resveratrol exerts its protective effect by alleviating the extent of oxidative status induced by nicotine. • Resveratrol improve the enzymatic/non-enzymatic antioxidant defense system in rats treated with combination of nicotine and resveratrol. • Resveratrol decreases the pathological changes in animals against the lung damage caused by nicotine., Male albino rats of Wistar strain were injected intraperitoneally with nicotine or/and resveratrol for 4 weeks. Serum Interleukin-2, Interleukin-6, alpha-fetoprotein and tumor necrosis-alpha, as well as plasma 8-hydroxydeoxyguanosine of nicotine-treated rats were increased significantly. Myeloperoxidase, xanthine oxidase, nitric oxide, lipid peroxidation and total oxidative status of the lung in nicotine-treated rats were increased significantly, which were brought down to normal in resveratrol co-treated group. Endogenous antioxidant status as the activity of superoxide dismutase, catalase, glutathione peroxidase, and glucose-6-phosphate dehydrogenases were found to be decreased significantly in the lung of the nicotine-treated group, which were significantly raised in resveratrol-administered groups. The non-enzymatic antioxidants as total antioxidant and thiol levels were decreased significantly as the effect of nicotine that was effectively enhanced by resveratrol treatment. The lung of nicotine-treated rats showed severe congestion of the alveolar lung tissues with scattered congestion per bronchiolar and perivascular cells, as well as, inflammatory cells were observed. The data suggested that resveratrol exerts its protective effect by modulating the extent of oxidative status and improving the enzymatic/non-enzymatic antioxidant defense system, moreover, decreases the pathological changes in animals against the lung damage caused by nicotine.

BACKGROUND: Oral submucous fibrosis (OSMF) is one of the common potentially malignant disorder prevailing in India. The primary etiological factors include tobacco and are canut which contain numerous Reactive Oxygen Species (ROS). The imbalance between ROS and antioxidant status creates oxidative stress. Reactive oxygen species attack guanine bases in DNA and form 8-Hydroxy Deoxyguanosine (8-OHdG) which can be detected in patients who have diseases associated with oxidative stress. The oxidative DNA damage produced by oxidative stress may induce malignant transformation. The aim of the present study is to detect the expression of 8 -OHdG in OSMF and compare the expression within the different grades and normal oral mucosa. AIM OF THE STUDY: To study the Immunohistochemical expression of 8-OHdG in oral submucous fibrosis. MATERIALS AND METHODS: A total of 30 samples were examined for the immunohistochemical expression of 8-OHdG. The control group includes 10 formalin fixed paraffin embedded tissue blocks of normal buccal mucosa. The study group includes 20 cases of formalin fixed paraffin embedded tissue blocks of oral submucous fibrosis (5cases of very early, early, moderately advanced, advanced cases of OSMF). 3 micron thickness sections were made from each sample and stained with 8-OHdG antibody. The expression is scored and analysed statistically. The results were statistically analysed using Kruskal-Wallis and Mann - Whitney U test. RESULTS: Statistically significant difference exists in the intensity of 8-OHdG expression between the study groups. Increased intensity in the oral submucous fibrosis samples were observed when compared with normal mucosa. The p value obtained was less than 0.001 which was highly statistically significant. Staining intensity was also compared with different grades of OSMF, the p value obtained was less than 0.01 which was statistically significant. CONCLUSION: Our present study is the first attempt to evaluate the expression of 8-OHdG in tissue samples that revealed the role of free radicals and oxidative DNA damage which enhances the initiation and progression of Oral submucous fibrosis. Further research with a larger sample size, clinicopathologic correlation and long term followup will shed more light on the pathogenesis of Oral submucous fibrosis. It will also be useful for the development of new therapeutic stratergies targeting treatment modalities for the oral submucous fibrosis.

Atmaca, Enes/0000-0002-8978-3755; Aksoy, Abdurrahman/0000-0001-9486-312X; Kutuk, Nukhet/0000-0001-6563-1899; YILMAZ, EREN/0000-0003-0298-734X WOS: 000501401300009 PubMed: 31109746 The actual role of splint therapy in preventing excessive loading of the temporomandibular joint (TMJ) is still debated. Lower intra-articular pressure levels have been measured in patients wearing occlusal splints, which may also reduce oxidative stress in the articular spaces. The aim of this study was to determine whether splint therapy reduces oxidative stress and inflammation in TMJ internal derangement patients by measuring interleukin 6 (IL-6), malondialdehyde (MDA), and 8-hydroxydeoxyguanosine (8-OHdG) levels in the synovial fluid (SF). Twenty-four patients with a temporomandibular disorder (TMD) were included in the study. TMJ SF samples were obtained prior to arthrocentesis. Twelve patients used a 2-mm hard acrylic, maxillary stabilization-type splint for 3 months after arthrocentesis. Twelve patients had no treatment after the SF aspiration. Second SF samples were obtained from all patients at 3 months post arthrocentesis. IL-6, MDA, and 8-OHdG levels in the samples were evaluated. All patients showed a significant symptomatic improvement after treatment (P < 0.005). No statistical correlation was found between the two groups concerning pre-treatment and 3-month SF levels of MDA, 8-OHdG, and IL-6. Although splint therapy was found to be successful in eliminating clinical symptoms of TMD, the results showed no beneficial effect on inflammation and oxidative stress markers in the synovial fluid. OMU Scientific Research Foundation [PYO.DIS.1901.15.005] This study was supported by OMU Scientific Research Foundation with the project number of PYO.DIS.1901.15.005.

There is considerable evidence that oxidative DNA damage is increased, DNA repair capacity is decreased in patients with Alzheimer's disease. Base excision repair is the major pathway in removal of oxidative DNA damage. 8-oxo-deoxyguanosine DNA glycosylase 1 (OGG1) is the enzyme which is involved in the first step of this repair process. Alterations in DNA repair capacity may be related with polymorphisms in DNA repair genes. In order to investigate the effect of OGG1 Ser326Cys polymorphism on oxidative DNA damage level, OGG1 genotyping was performed, basal and oxidative DNA damage in lymphocytes and 8-OHdG level in plasma were examined in patients with Alzheimer's disease. Basal and oxidative DNA damage and 8-OHdG level were measured by OGG1-modified comet assay and enzyme-linked immunoassay, respectively. OGG1 genotyping was performed by polymerase chain reaction- restriction fragment length polymorphism assay. Basal and oxidative DNA damage and plasma 8-OHdG levels were found to be higher in the Alzheimer's disease group than those in the control group (P 0.001). In the Alzheimer's disease group, the levels of oxidative DNA damage was higher in the patients having OGG1 (Ser326Cys + Cys326Cys) genotype than those in the patients having OGG1 Ser326Ser genotype. It was concluded that oxidative DNA damage is increased in patients with Alzheimer's disease and OGG1 Ser326Cys polymorphism may be responsible for this increase.

We previously reported that dietary acrylamide, at doses (10 and 50 mg/kg diet) known to cause rodent tumors, lowered serum total high density lipoprotein and total testosterone, increased serum lipase, and lowered lymphocytes levels together with other hematological parameters in male F344 rats exposed for 10 weeks (doi: 10.1016/j.etap.2014.11.009 [1]). Here we present data related to the role of food-borne acrylamide exposure (at 0, 5, 10 and 50 mg/kg diet) in the presence of low (7% wt/wt) or high (23.9% wt/wt) dietary fat on serum and urinary markers of oxidative stress and inflammation in F344 rats. Briefly, urine and serum samples were collected from the experimental animals a day prior to or at the time of necropsy, respectively and processed for enzyme-linked immunosorbent assay estimations of biochemical markers. Urine samples were analyzed for 8-hydroxydeoxyguanosine and isoprostane, and serum samples for total antioxidant capacity, paraoxonase 1 activity, c-reactive protein, homocysteine, oxidized low-density lipoprotein, intercellular adhesion molecule-1, thromboxin 2, and Nε-(carboxymethyl)lysine. Keywords: Acrylamide, Food safety, Systemic toxicity, Oxidative stress, Inflammation, 8-Hydroxydeoxyguanosine, Isoprostane, Total antioxidant capacity, Paraoxonase 1, C-reactive protein, Homocysteine, Oxidized low-density lipoprotein, Intercellular adhesion molecule-1, Thromboxin 2, Nε-(carboxymethyl)lysine

This study was designed to explore the protective effect of allicin on aortic endothelial cell injury induced by high glucose/hypoxia and to investigate the corresponding mechanisms. The primary-cultured murine aortic endothelial cells were subcultured. The third passage of cells was adopted and randomly divided into five groups: The normal group (NG), the mannitol group (MG), the high-glucose/hypoxia group (HG), the allicin group (AG) and the protein kinase C (PKC) inhibitor group (GG). The general morphology was observed under an inverted phase-contrast microscope and cell viability was assessed using the MTT assay. Intracellular reactive oxygen species (ROS) levels in the endothelial cells were quantified using dihydroethidium staining. The levels of 8-hydroxydeoxyguanosine (8-OHdG), nuclear factor-κB (NF-κB), NADPH oxidase 4 (Nox4) and hypoxia-inducible factor-1α (HIF-1α) and the activity of PKC were measured using ELISA. A quantitative polymerase chain reaction (qPCR) was adopted to evaluate the mRNA expression of Nox4, HIF-1α and NF-κB. The altered cell morphology observed in HG was notably ameliorated in the AG and GG. The protein levels of 8-OHdG, NF-κB, Nox4, HIF-1α and PKC in the HG were higher than those in the other groups. Furthermore, the cell viability in the AG was significantly increased and the protein levels of 8-OHdG, NF-κB, Nox4, HIF-1α and PKC were significantly decreased compared with those in the HG. The ROS production was found to be increased in the HG cells, while there was a significant decrease in the AG cells. These data indicate that allicin exerts a protective effect against high glucose/hypoxia-induced injury in aortic endothelial cells through its antioxidative action, which may involve the inhibition of the PKC pathway and regulation of HIF-1α.

Aims Previous studies have supported the claim that psychological stress induces the production of reactive oxygen species. Several authors have suggested that patients with psychiatric disorders show high levels of oxidative stress markers. We examined different oxidative stress markers in patients with chronic schizophrenia. Methods This study included 29 patients with chronic schizophrenia and 30 healthy volunteers. The concentration of urinary biopyrrins and 8-hydroxydeoxyguanosine (8-OHdG), as measured by enzyme-linked immunosorbent assay, were normalized to the urinary concentration of creatinine. Psychiatric symptoms were assessed by the administration of the Brief Psychiatric Rating Scale (BPRS). Results The concentration of biopyrrins in patients with chronic schizophrenia was significantly higher when compared with healthy volunteers. The correlation between biopyrrin level and the duration of illness was highly significant. There were no significant differences in the levels of urinary 8-OHdG between the two groups. In schizophrenic patients, the level of urinary biopyrrins showed correlations with BPRS scores, while the level of urinary 8-OHdG did not show correlations with BPRS. Conclusions Urinary biopyrrins are increased in patients with chronic schizophrenia while urinary 8-OHdG is not increased. These findings suggest that patients with chronic schizophrenia are under the condition of certain oxidative stresses.

Electroplating workers are using chromium during the working process. Clinical and laboratory evidence indicates that exposure of chromium is very toxic if it is inhaled and can lead to oxidative DNA damage. This study was aimed to investigate factors associated to the urinary 8 - OHdG levels as a biomarker of oxidative DNA damage. Sixty six subjects from electroplating home industry in Tegal, Central Java were included. Urinary chromium levels were determined using AAS. The urinary 8-OHdG level as oxidative DNA damage was measured using ELISA. The levels of chromium in all sample were higher than the normal range (median 11.77 μg/L), the median of urinary 8-OHdG level was 23.83 ng/ml. Eventhough, age and urinary chromium level were not associated with urinary 8-OHdG's levels, there was a significant association between the period of works and the type of jobs to the urinary 8 - OHdG levels.

Background/purpose: The two direct dental restorative materials most commonly used today are silver-mercury amalgam and resin-based composites. The purpose of this study was to examine the effects of these two restorative materials and substances released by these into the oral environment on lipid peroxidation and DNA oxidation after entering the blood circulation. Materials and methods: Blood samples from 41 patients were collected before and 24 hours after the application of these restorative materials. The 8-hydroxydeoxyguanosine/deoxyguanosine ratio in these samples was measured to determine oxidative DNA damage, and malondialdehyde levels were measured to define lipid peroxidation. The paired samples t test and Pearson correlation analysis were used for the analysis of variables (α=0.05). Results: While no statistically significant difference was observed after amalgam filling application in terms of DNA oxidation, a significant difference was observed after composite application (P

Foot-and-mouth disease (FMD) is an acute, contagious viral disease in cattle that is associated with enormous economic losses in Turkey and worldwide. The purpose of this study was to determine changes in serum malondialdehyde (MDA), coenzyme Q10 (CoQ10), 8-hydroxydeoxyguanosine (8-OHdG) and deoxyguanosine (dG) and to perform histopathological examinations in calves with FMD. Thirty calves were studied, 20 of which were infected with FMD and 10 were free of the disease. Following a routine clinical examination, blood samples were obtained, and serum MDA, CoQ10, 8-OHdG and dG levels were determined. Necropsy and histopathological examinations were performed on dead calves with FMD. MDA and 8-OHdG/106dG levels were significantly higher in calves with FMD than in the control group. However, the increase in CoQ10 levels in calves with FMD, compared with the control group, was not statistically significant. Macroscopic examination of the heart tissue of calves with acute myocarditis revealed the presence of pale, yellowish gray-white necrotic muscle fibers in the ventricular wall of the heart. The muscle fibers in the myocardium were swollen and exhibited pyknotic nuclei and intense lymphocytic cell infiltration. In longitudinal sections, the muscle fibers were non-striated, swollen, and homogenously pink and contained pink nuclei. Between muscle fibers, intense mononuclear cell infiltration was observed. The findings of the present study indicate that oxidative stress is significantly increased in calves with FMD, and that oxidative DNA damage may play an important role in the etiopathogenesis of FMD. This is the first study to report CoQ10 and 8-OHdG levels in calves with FMD, and its findings may serve as the basis for future studies on this subject.

Studies have used 8-hydroxydeoxyguanosine (8-OHdG) as a biomarker to detect systemic oxidative DNA damage associated with oxidative stress. However, studies on the association between exposure to tobacco smoking and urinary 8-OHdgG give inconsistent results. Limited studies have estimated the oxidative stress among office workers. This study assessed the association between urinary 8-OHdG and cotinine for office workers. Workers (389) including smokers, ex-smokers and non-smokers from 87 offices at high-rise buildings in Taipei participated in this study with informed consent. Each participant completed a questionnaire and provided a spot urine specimen at the end of work day for measuring urinary 8-OHdG and cotinine. The carbon dioxide (CO2) levels in workers’ offices were also measured. The questionnaire reported socio-demographic characteristics, life styles and allergic history. The urinary 8-OHdG level increased with the cotinine level among participants (Spearmans’ rho = 0.543, p < 0.001). The mean of urinary 8-OHdG and cotinine was 5.81 ± 3.53 μg/g creatinine and 3.76 ± 4.06 μg/g creatinine, respectively. Comparing with non-smokers, the adjusted odds ratio (OR) of having urinary 8-OHdG greater than the median level of 4.99 μg/g creatinine was 5.30 (95% confidence intervals (CI) = 1.30–21.5) for current smokers and 0.91 (95% CI = 0.34–2.43) for former smokers. We also found workers exposed to 1,000 ppm of CO2 at offices had an adjusted OR of 4.28 (95% CI = 1.12–16.4) to have urinary 8-OHdG greater than 4.99 μg/g creatinine, compared to those exposed to indoor CO2 under 600 ppm. In conclusion, urinary 8-OHdG could represent a suitable marker for measuring smoking and CO2 exposure for office workers.

The aim of this study was to determine 8-hydroxydeoxyguanosine (8-OH-dG) levels in trichloroethylene (TCE)-exposed workers. Oxidative stress biomarkers and biochemical parameters were monitored among 26 TCE-exposed workers and 78 age-matched control subjects. Levels of urinary 8-OH-dG were analyzed by liquid chromatography tandem mass spectrometry. Urinary 8-OH-dG levels were significantly higher for TCE-exposed group (p < .001). Spearman's correlation test revealed positive correlations between urinary trichloroacetic acid levels and age, urinary 8-OH-dG, urinary total oxidant status, and urinary total antioxidant status (p = .042, p < .001, p < .001, and p < .001, respectively). 8-OH-dG may be a useful marker to determine the extent of TCE exposure.

Insulin resistance is one of the feature of obesity. Fetuin A is inhibitor of insulin receptor which belongs the family of receptor tyrosine kinase. It has been observed that fetuin-null mice are resistant to diet-induced obesity and they exhibit increased insulin sensitivity. Increased production of reactive oxygen species is suggested to be associated with insulin resistance. Attacks of reactive oxygen species to DNA results in base oxidation. Among the oxidized bases, 8-hydroxydeoxyguanosine is predominant lesion with pro-mutagenic potential. In the present study; measurement of serum levels of fetuin A and 8-hydroxydeoxyguanosine in obese subjects (n=46) and healthy controls (n=22), and examination of the relations between these parameters and insulin resistance have been purposed. Blood samples were taken form morbidly obese subjects after a 12 h fasting. Serum levels of fetuin A and 8-hydroxydeoxyguanosine were measured by ELISA. Statistical analysis was performed by Mann Whitney U test and correlations were examined by Spearman correlation coefficient. Serum levels of total cholesterol, HDL, LDL, VLDL, triglycerides, free T3, free T4, fasting glucose, c-peptide and %HbA1c in the obese group were found to be different from those in the control group. Serum level of fetuin A was found to be higher, 8-hydroxydeoxyguanosine level was found to be lower in the morbid obese group than those in the control group. Fetuin A was found to be positively correlated with HOMA-IR (r:0,40, P

Graphical abstract, Highlights • Gasoline station attendants have higher urinary t,t,-MA and 8-OHdG levels. • There is strong correlation between 8-OHdG and benzene exposure level. • 8-OHdG levels are significantly correlated also with job seniority. • Low-level chronic exposure to benzene can determine oxidative damage on DNA., The present study aims to investigate the relation between exposure to low-dose benzene and the occurrence of oxidative DNA damage in gasoline station workers, as well as the possible role of interfering or confounding factors. Urine levels of 8-OHdG were evaluated by a competitive immunoassay in a group of 80 men, employed in gasoline stations located in East Sicily and compared with a control group (n = 63) of male office employees not occupationally exposed to benzene. Information regarding socio-demographic characteristics, lifestyle and job-related records were provided through a questionnaire. Significantly higher (p

Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most frequent cause of inherited Parkinson's disease (PD). The most common PD-associated LRRK2 mutation, G2019S, induces increased production of reactive oxygen species in vitro. We therefore hypothesized that individuals with PD-associated LRRK2 mutations might have increased concentrations of oxidative stress markers and/or decreased total antioxidant capacity (TAC) in their cerebrospinal fluid (CSF). We measured two oxidative stress markers, 8-hydroxy-2’-deoxyguanosine (8-OHdG) and 8-isoprostane (8-ISO), and TAC in CSF from LRRK2 mutation-bearing PD patients (LRRK2 PD = 19), sporadic PD patients (sPD = 31), and healthy control subjects with or without these mutations (LRRK2 CTL = 30, CTL = 27). 8-OHdG and 8-ISO levels were increased in LRRK2 CTL subjects, while TAC was similar between groups. 8-ISO was negatively correlated, and TAC was positively correlated, with Montreal Cognitive Assessment (MoCA) scores in LRRK2 PD, LRRK2 CTL, and CTL subjects. Correlations in both groups of PD patients between the two oxidative stress markers and Unified Parkinson Disease Rating Scale (UPDRS) Total scores were weak, while TAC was negatively correlated with these scores. These findings suggest that oxidative stress may be increased in the CNS in healthy individuals with PD-associated LRRK2 mutations, perhaps contributing to their risk for PD. Further, TAC may decrease in the CNS with the progression of PD, and when cognitive impairment is present regardless of the presence or absence of PD.

Background In Belgium, around 8.5% of the children have asthmatic symptoms. Increased asthma risk in children has been reported in relation to exposure to phthalate plasticizers but the underlying mechanisms are largely unknown. Aim The aim of this study was to identify if oxidative stress, assessed by excision of 8-hydroxydeoxyguanosine (8-OHdG) from damaged DNA, is an intermediate marker for the association between phthalate exposure and doctor-diagnosed asthma. Material and methods In 418 14–15-year-old youngsters, recruited as a representative sample of residents of Flanders (Belgium), personal exposure to phthalates was assessed by measuring phthalate metabolites in urine: mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono-n-butyl phthalate (MnBP), mono-benzyl phthalate (MBzP), mono-isobutyl phthalate (MiBP) and mono-ethyl phthalate (MEP). Analysis of 8-OHdG in urine was used as a sensitive biomarker of oxidative stress at the level of DNA. The presence of doctor-diagnosed asthma was elicited by a self-administered questionnaire. Associations were assessed using multiple linear and logistic regression models. Mediation was tested using Baron and Kenny's regression approach. Results A significant increased risk of a youngster being diagnosed with asthma was found for both urinary MnBP (metabolite of dibutyl phthalate (DBP)) and the sum of the three di(2-ethylhexyl) phthalate metabolites (ΣDEHP = MEHP + MEHHP + MEOHP), with respective odds ratio of 1.84 [95% CI: 1.02, 3.32] for MnBP and 1.94 [95% CI: 1.07, 3.51] for ΣDEHP. In addition, we observed significant associations between all urinary phthalate metabolites and increased urinary levels of 8-OHdG. The associations were stronger in girls than in boys. We did not found evidence that 8-OHdG was associated with doctor-diagnosed asthma. Conclusion The results of our study are in line with other findings from epidemiological surveys and raise further concern about DEHP and DBP as risk factors for asthma, however, the underlying mechanisms are not yet well understood.

Age-associated declines in protein homeostasis mechanisms (proteostasis) are thought to contribute to age-related neurodegenerative disorders. The increased oxidative stress which occurs with aging can activate a key proteostatic process, chaperone-mediated autophagy. This study investigated age-related alteration in cerebrospinal fluid concentrations of heat shock 70-kDa protein 8 (HSPA8), a molecular chaperone involved in proteostatic mechanisms including chaperone-mediated autophagy, and its associations with indicators of oxidative stress (8-hydroxy-2’-deoxyguanosine [8-OHdG] and 8-isoprostane) and total anti-oxidant capacity. We examined correlations between age, HSPA8, 8-OHdG, 8-isoprostane, and total antioxidant capacity in CSF samples from 34 healthy subjects ranging from 20 to 75 years of age. Age was negatively associated with HSPA8 (rho = -0.47; p = .005). An age-related increase in oxidative stress was indicated by a positive association between age and 8-OHdG (rho = 0.61; p = .0001). HSPA8 was moderately negatively associated with 8-OHdG (rho = -0.58; p = .0004). Age and HSPA8 were weakly associated with 8-isoprostane and total antioxidant capacity (range of rho values: -0.15 to 0.16). Our findings in this exploratory study suggest that during healthy aging, cerebrospinal fluid HSPA8 may decrease, perhaps due in part to an increase in oxidative stress. Our results also suggest that 8-OHdG may be more sensitive than 8-isoprostane for measuring oxidative stress in cerebrospinal fluid. Further studies are indicated to determine if our findings can be replicated with a larger cohort, and if the age-related decrease in HSPA8 in cerebrospinal fluid is reflected by a similar change in the brain.

Background Helicobacter pylori (H. pylori) infection is reported to be associated with various extragastrointestinal conditions such as insulin resistance, diabetes mellitus and metabolic syndrome. H. pylori infection and type 2 diabetes mellitus (T2DM) are associated with oxidative stress, this cross-relation between H. pylori induced infection in T2DM and oxidative damage is still debated. Thus, the question arises whether an increase in the serum level of 8-OHdG and Ox-LDL will occurs in patients with T2DM infected H. pylori; this will be through determination and compare frequency of H. pylori infection in T2DM and non-diabetic patients. Methods 100 patients presented with history of epigastric discomfort for more than 1 month; 50 patients with T2DM and 50 non-diabetics. Anti-H. pylori IgG using ELISA, fasting and postprandial glucose level, glycated hemoglobin (HbA1c) and body mass index (BMI) was calculated. Serum 8-OHdG and Ox-LDL was measured using ELISA for the 100 patients and 50 control subject. Results Rates of H. pylori infection of T2DM and non-diabetic were 66 and 58 %, respectively, (p = 0.001). H. pylori IgG antibody was not correlated with HbA1c either in T2DM (p = 0.06) or non-diabetic (p = 0.25). Serum 8-OHdG level in T2DM with positive H. pylori infection showed a significant difference compared to non-diabetics with positive H. pylori infection (p = 0.001) and higher than that in T2DM with negative H. pylori. A correlation between 8-OHdG concentration and HbA1c in T2DM patients infected with H. pylori was observed (r = 0.39, p = 0.02). Serum Ox-LDL level in T2DM with positive H. pylori infection showed a significant difference compared to diabetics with both negative H. pylori infection and in non-diabetics with positive H. pylori infection (p = 0.001). Conclusions Increased levels of oxidative DNA damage (8-OHdG) and Ox-LDL suggest the mechanistic link between H. pylori infection combined with diabetes and increased generation of ROS and could play as an important image for high risk to atherosclerosis.

8-Hydroxydeoxyguanosine (8-OHdG) is one of the most reliable and abundant markers of DNA damage. The study was designed to explore the relationship between urinary 8-OHdG and renal cell carcinoma (RCC) and to investigate whether individuals with a high level of 8-OHdG would have a modified odds ratio (OR) of arsenic-related RCC. This case–control study was conducted with 132 RCC patients and 245 age- and sex-matched controls from a hospital-based pool between November 2006 and May 2009. Pathological verification of RCC was completed by image-guided biopsy or surgical resection of renal tumors. Urinary 8-OHdG levels were determined using liquid chromatography with tandem mass spectrometry (LC–MS/MS). Concentrations of urinary arsenic species, including inorganic arsenic, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), were determined by a high performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. Level of urinary 8-OHdG was significantly associated with the OR of RCC in a dose–response relationship after multivariate adjustment. Urinary 8-OHdG was significantly related to urinary total arsenic. The greatest OR (3.50) was seen in the individuals with high urinary 8-OHdG and high urinary total arsenic. A trend test indicated that the OR of RCC was increased with one of these factors and was further increased with both ( p = 0.002). In conclusion, higher urinary 8-OHdG was a strong predictor of the RCC. High levels of 8-OHdG combined with urinary total arsenic might be indicative of arsenic-induced RCC.

This study explored the effects of long-term bathing in radon hot springs on oxidative damage and antioxidation function in humans. In this study, blood was collected from residents in the Pingshan radon hot spring area (RHSA), Jiangzha RHSA, and control area (CA). 8-Hydroxydeoxyguanosine (8-OHdG) and thioredoxin reductase (TrxR), representing oxidation and antioxidant levels, respectively, were analyzed as indices. Compared to the CA group, the RHSA group in the Pingshan and Jiangzha areas showed significantly decreased 8-OHdG levels ( Z = −3.350, −3.316, respectively, P < .05) and increased TrxR levels ( Z = 2.394, 3.773, respectively, P < .05). The RHSA and CA groups in Jiangzha had lower levels of TrxR and 8-OHdG compared to those in Pingshan. This finding may be related to the different radon concentration levels, bathing time and other factors. Results suggested that long-term bathing in radon hot spring may activate antioxidant function and reduce oxidative damage in the body.

To examine the relations between the burden of blood copper (B-Cu), blood ferrous (B-Fe), and the oxidative stress in people around electronic waste (e-waste) recycling sites, this study measured and analyzed the level of urinary 8-Hydroxy-2'-deoxyguanosine (8-OHDG) of these people. Exposed groups, consisted of female groups (directly exposed group n=100, indirectly exposed group n=54) and male groups (directly exposed group n=98, indirectly exposed group n=34), were chosen from e-waste recycling sites. Control group (female n=59, male=32) was selected from a green plantation. Questionnaire surveys for risk factors were also performed. Results indicated the male directly exposed group (lg8-OHDG nmol/mol creatinine, mean±SD, 3.55±0.49) showed a lower 8-OHDG level than the male control group (lg8-OHDG nmol/mol creatinine, mean±SD, 3.89±0.29) (p0.01), Meanwhile, an elevated B-Fe in male directly exposed group (lgB-Fe ug/L 3.11±0.25) were observed compared with the male control group (lgB-Fe ug/L 2.83±0.22) (p0.01). The levels of urinary 8-OHDG were negatively associated with blood ferrous, as confirmed by linear regression model (unstandardized regression coefficient, beta=-0.215, p0.05). The present study suggests that the exposure to e-waste might cause the elevation of B-Fe and result in the changes of urinary 8-OHDG levels.

This study examines the relationship between urinary arsenic concentration and urinary 8-hydroxydeoxyguanosine (8-OHdG) concentrations, an index of oxidative DNA damage, among women who live near abandoned metal mines. The sample consisted of 165 residents living near two abandoned metal mines located in Chungbuk Province. Demographic characteristics as well as environmental factors relevant to arsenic exposure were collected through interviews, and urinary arsenic concentrations and urinary 8-OHdG concentrations of the research subjects were measured. The collected data were subsequently analyzed using the statistics program SPSS 12.0. T he geometric average of urinary arsenic concentrations among the research subjects was 5.65 μg/g creatinine. In a correlation analysis between urinary arsenic and 8-OHdG concentrations, the correlation coefficient was significant (p

Background: Chronic inflammation is linked to an increased risk of cancer. The molecular mechanisms underlying this correlation have been long investigated and it is well known that the inflammatory cells recruited in the inflamed tissues release chemical mediators, in particular reactive oxygen species (ROS). With respect to digestive systems, ROS have been implicated in a number of pathologies, including Helicobacter pylori-related gastritis, Barrett’s esophagus, inflammatory disease of the lower gastrointestinal tract, alcoholic liver disease and several other types of toxic and virus-mediated liver injury. ROS levels within cells and tissues are controlled by numerous antioxidant defense mechanisms, but in inflammation, ROS overproduction exceeds defenses and damage intracellular macromolecules, including nucleic acids, with formation of potentially mutagenic and carcinogenic DNA adducts. Aims: This paper summarizes our own experience investigating the link between inflammation, ROS production and oxidative DNA damage as well as the impact of the above events on cytokine and growth factor release, oncogene activation, telomere instability and microRNA in H. pylori-related gastritis, Barrett’s esophagus and, in particular, hepatitis C virus-related liver disease. The paper also describes, at least in part, the complex scenario involving nitric oxide production and its impact in some gastrointestinal diseases, as well as a number of other molecular and biochemical changes related to ROS production and inflammation. Conclusions: The paper falls obviously short of being an exhaustive summary of our understanding, but the data reported are intended as a stimulus to broaden the knowledge on the topic, also in view of the possible therapeutic implications of any advance obtained.

Using the urinary 8-hydroxydeoxyguanosine (8-OHdG) concentration, effects of participation in a two-day ultramarathon race period on oxidative DNA damage were investigated in Japanese nonprofessional runners. Before the first day (baseline), after the first day (mid-race) of 40-km running, and after the second day (post-race) of 90 km running, biomaterials were successfully sampled from 95 participants (males, 79; females, 16) who completed the full race. We analyzed urine for 8-OHdG and blood for aspartate aminotransferase (AST), creatine phosphokinase (CPK) and myoglobin, and evaluated fluctuation in the values at three sampling time points. Adjusted baseline urinary 8-OHdG levels (microg/g creatinine) (mean +/- standard deviation) showed no significant differences between males and females, at 2.85 +/- 1.17 and 3.04 +/- 1.56, respectively. In males, mid-race urinary 8-OHdG levels rose to 3.29 +/- 1.15 (p < 0.01), but then returned to 2.73 +/- 1.16 at the post-race time point (p < 0.01). In females, a similar increase to 3.32 +/- 1.47 and subsequent decline to 2.80 +/- 1.47 were noted. In contrast, AST, CPK and myoglobin were increased at both mid- and post-time points and particularly the latter, independent of the sex. Extreme prolonged exercise in a two-day ultramarathon race period causes oxidative DNA damage but antioxidant repair systems are apparently induced to protect against oxidative DNA stress with physical exercise.

Background Oxidative stress is implicated in the pathogenesis of migraine, but no published studies have examined both oxidative stress levels and oxidative DNA damage on the same patient group. Methods In this study, total oxidant status (TOS); total antioxidant status (TAS); oxidative stress index (OSI); and 8-hydroxy-2′-deoxyguanosine (8-OHdG), which is an indicator of oxidative DNA damage, were measured in the plasma samples of 50 prophylactic unmediated migraineurs (11 with aura and 39 without aura) and 30 matched healthy volunteers. Results No significant differences in TAS, TOS, and OSI values were observed between patients and controls. However, plasma 8-OHdG levels were found to be significantly higher in migraine patients than in the control group (p = 0.001); this increase in plasma 8-OHdG levels was more prominent in cases with migraine without aura than with aura (p = 0.001). Our results suggested an evidence of oxidative stress-related DNA damage in migraine. Conclusion DNA damage reflected by plasma 8-OHdG did not studied in migraine before. Therefore, further research on oxidative stress-related DNA damage and the extent of its clinical manifestations in migraine may provide additional data to our current knowledge.

Oxidative stress is involved in the pathogenesis of many eye diseases, including dry eye syndrome, cataract, and age-related macular degeneration [1,2,3]. Oxidative stress impairs cellular function by damaging lipids, proteins, RNA, and DNA, in addition to causing inflammation and cell death [4,5]. 8-Hydroxydeoxyguanosine (8-OHdG), an oxidized DNA nucleoside, results from the oxidation of guanine and is excreted in bodily fluids [6,7]. 8-OHdG is one of the most widely used biomarkers of cellular oxidative stress [6]. Malondialdehyde (MDA) is an endogenous genotoxic product of enzymatic and oxygen radical-induced lipid peroxidation [8]. Aqueous humor is continually produced by the ciliary body and is in direct contact with the anterior surface of the lens, iris, and corneal endothelial cells, before draining out of the eye via the trabecular meshwork [8,9]. Oxidative stress in aqueous humor reflects the balance among the oxidative states of the lens, corneal endothelium, and retina. Corneal endothelial cells are in direct contact with the aqueous humor [9] and can therefore secret their metabolic products directly into the aqueous humor, whereas metabolic products from lens epithelial cells and the retina must diffuse through the anterior lens capsule and anterior hyaloids membrane to reach the aqueous humor [10]. High myopia has been reported to be associated with various complications and is defined as a long axial length (AXL) [11,12]. Retinal degeneration is one of the major complications leading to severe vision loss [11,12]. Many causes of high myopic retinal degeneration, including oxidative stress and retinal ischemia, have been suggested [11,13]. An association between AXL and cytokine levels in aqueous humor has also been reported [14,15,16]. However, to the best of our knowledge, oxidative stress level in the aqueous humor of patients with high myopia has not yet been evaluated. In this study, we investigated the oxidative stress status of aqueous humor in patients with high myopia and corresponding controls.

Oxidative DNA damage is believed to be involved in the aging process. Species with shorter potential life spans generally have a higher specific metabolic rate (SMR), and would be expected to have increased levels of oxidative stress and DNA damage, as compared to long-lived species. An automatized HPLC method based on electrochemical detection was used to measure the levels of the oxidative DNA damage markers 8-hydroxydeoxyguanosine (8-OH-dG) and 8-hydroxyguanine (8-OH-Gua) in urinary samples from mammals with various potential life spans (mice, rats, guinea pigs, cats, chimpanzees, and humans). There was no significant linear correlation (r = -0.71, p = 0.11) between the species' potential life spans (log transformed) and the urinary levels of 8-OH-dG as normalized to creatinine (8-OH-dG/creatinine), although the species with longer life spans, such as chimpanzee and human, had among the lowest levels detected. In contrast, the negative linear correlation between the species' potential life span (log transformed) and the urinary levels of 8-OH-Gua as normalized to creatinine (8-OH-Gua/creatinine), was significant (r = -0.97, p = 0.002). In addition, there was a positive linear and significant correlation between SMR and 8-OH-dG/creatinine (r = 0.91, p = 0.01) or 8- OH-Gua/creatinine (r = 0.90, p = 0.01). These results suggest that 8-OH-Gua, rather than 8-OH-dG, may be a more general marker for oxidative damage.

Reactive oxygen species (ROS) enhance myocardial ischemia-reperfusion (I/R) injury. Ischemic preconditioning (PC) provides potent cardioprotective effects in I/R. However, it has not been elucidated whether PC diminishes ROS stress in I/R and whether PC protects the myocardium from ROS stress transmurally and homogeneously. Isolated rabbit hearts perfused with Krebs-Henseleit buffer underwent 30 min of ischemia and 60 min of reperfusion. Hemodynamic changes and myocardial damage extent were analyzed in four groups. The control group underwent I/R alone. The H2O2 group underwent I/R with H2O2 infusion (50 μM) in the first minute of reperfusion to enhance oxidative stress. The PC and H2O2+PC groups underwent 5 min of PC before control and H2O2 protocols, respectively. Extracted myocardial DNA was analyzed for 8-hydroxydeoxyguanosine (8-OHdG), an indicator of oxidative DNA damage, with the use of the HPLC-electrochemical detection method. Glutathione peroxidase (GPX) activity and the reduced form of GSH were measured by spectrophotometric assays. The myocardial infarct size was significantly reduced in the PC group (19 ± 2%) compared with the control group (37 ± 4%; P < 0.05), particularly in the subendocardium. H2O2 transmurally increased the infarct size by 59 ± 4% ( P < 0.05), which was significantly diminished in the H2O2+PC group (31 ± 4%; P < 0.01). The GSH levels, but not GPX activity, were well preserved transmurally in protocols with PC. The 8-OHdG levels were significantly decreased in PC and were significantly enhanced in H2O2 ( P < 0.01). These changes in oxidative DNA damage were effectively diminished by PC. In conclusion, PC enhanced the scavenging activity of GSH against ROS transmurally, reduced myocardial damage, particularly in the subendocardium, and diminished the transmural difference in myocardial infarct size.

The effects of glucose and fructose in the presence or absence of iron or copper on the formation of 8-hydroxydeoxyguanosine (8-OHdG) in calf-thymus DNA were examined. Glucose (5 and 10 mM) and fructose (10–200 μM) increased 8-OHdG formation 1.9–2.8 times and 3.0–8.3 times compared to the control, respectively. In the presence of fructose (200 μM), copper (50 μM) was found to increase 8-OHdG formation 46.2 times compared to the control, and 3.8 times compared to the iron (50 μM)-treated value. The stimulatory potency of 8-OHdG formation by fructose (200 μM) in the presence of copper (50 μM) was much stronger than that by glucose (10 mM) in the presence of iron (50 μM) or of copper (50 μM). Sorbitol, 3-deoxyglucosone and methylglyoxal in the presence or absence of copper had no or weaker stimulating effects on 8-OHdG formation than fructose in the presence or absence of copper. These results suggest that fructose in the presence of copper has the potential to dramatically induce oxidative DNA damage.

Oxidative DNA damage and repair, as measured by 8-hydroxy-2'-deoxyguanosine (8-OHdG) in urine and DNA samples were studied in association with work-related diesel exhaust exposure among garage and waste collection workers. Seasonal variations of the urinary 8-OHdG levels in pre- and two post-workshift urine samples of 29 exposed workers and 36 control persons were evaluated. The mean+/-SE levels of post-workshift 8-OHdG (mumol/mol crea) were 1.52+/-0.44 in winter and 1.61+/-0.33 in summer for the exposed workers, and 1.56+/-0.61 in winter and 1.43+/-0.49 in summer for the controls, respectively. No significant difference in the urinary 8-OHdG levels between exposed workers and control subjects in winter (p=0.923) and summer (p=0.350) was observed. A linear mixed model, adjusted for years of employment, age, ex/non-smoking and BMI, indicated no significant dose exposure-relationships between the urinary 8-OHdG and 15 PAH air concentrations nor between the 8-OHdG and 7 PAH monohydroxy-metabolites analyzed in the same workers. 8-OHdG was also analyzed in the mononuclear cell DNA of 19 exposed and 18 control subjects. The mean value of 8-OHdG/non-modified 2'-deoxyguanosine (8-OHdG/105 dG+/-SE) were 4.89+/-0.17 for the exposed and 4.11+/-0.16 for the control persons, which showed no correlation with the urinary 8-OHdG levels (r=0.01, n=28, P=0.96). The PAH exposure at workplaces was mainly composed of volatile compounds, particularly naphthalene, suggesting low exposure through the respiratory tract and a low effect of PAH in ROS induction.

Recently, H. Kasai reported an automatic, precise method of 8-hydroxydeoxyguanosine (8-OH-dG) analysis in urine by high performance liquid chromatography coupled to an electrochemical detector (HPLC-ECD). It is based on a cleaning-up step by anion-exchange chromatography and a further purification step using reverse phase chromatography before detection, by the ECD. In this communication, we report a method for the simultaneous determination of 8-OH-dG and creatinine, an internal standard for normalizing the excretion of 8-OH-dG in urine.

With a recently developed high-performance liquid chromatography (HPLC) method based on anion exchange chromatography, precise fraction collection, and reversed-phase chromatography, the oxidative DNA damage marker 8-hydroxydeoxyguanosine (8-OH-dG) was measured in human urine samples. The HPLC analysis was further modified to measure 8-OH-dG in rat and mouse urine samples. In addition, the urinary RNA degradation product 7-methylguanine (m7Gua) was analyzed simultaneously. The correlation coefficient (r) for the correlation between urinary creatinine and m7Gua was 0.9 for rats and 0.8 for humans and mice. Levels of 8-OH-dG in relation to urinary creatinine were compared and found to be similar for humans and rats and twice as high for mice. Urinary levels of m7Gua, as normalized to creatinine, were several-fold higher in rodents as compared with human levels, thereby correlating with the higher resting metabolic rate of rodents. The presented results show that 8-OH-dG and m7Gua can be analyzed simultaneously and reliably in urine from humans and rodents. In addition, m7Gua may be used as a reliable marker instead of creatinine for the normalization of 8-OH-dG in urine from rats and mice and also may be used in addition to normalization with creatinine in measurements of 8-OH-dG in human urine samples.

Previous investigations indicate that engine room personnel on ships are exposed to polycyclic aromatic hydrocarbons (PAH) from oil and oil products, with dermal uptake as the major route of exposure. Several PAH are known carcinogens and mutagens.To investigate the urinary excretion of a marker for oxidative DNA damage, 8-hydroxydeoxy-guanosine (8OHdG), in engine room personnel, and to study the association between 8OHdG and 1-hydroxypyrene (1OHP), a biological marker for PAH exposure.Urine samples were collected from engine room personnel (n = 36) on 10 Swedish and Norwegian ships and from unexposed controls (n = 34) with similar age and smoking habits. The exposure to oils, engine exhaust, and tobacco smoke 24 hours prior to sampling was estimated from questionnaires. The urinary samples were frozen for later analyses of 8OHdG and 1OHP by high performance liquid chromatography.Excretion in urine of 8OHdG (adjusted to density 1.022) was similar for controls (mean 18.0 nmol/l, n = 33), and for those who had been in the engine room without skin contact with oils (mean 18.7 nmol/l, n = 15). Engine room personnel who reported skin contact with oil had increased excretion of 8OHdG (mean 23.2 nmol/l, n = 19). The difference between this group and the unexposed controls was significant. The urinary levels of ln 1OHP and ln 8OHdG were significantly correlated, and the association was still highly significant when the effects of smoking and age were accounted for in a multiple regression analysis.Results indicate that exposure to PAH or possibly other compounds from skin contact with oils in engine rooms may cause oxidative DNA damage.

Since the discovery of 8-OH-dG formation, various aspects of oxidative DNA damage have been studied. In the present decade, we have studied the chemistry of oxidative DNA damage, its mutagenic effects, and its repair mechanisms. We are also analyzing 8-OH-dG levels in human samples, such as leukocytes and urine, as a marker of oxidative DNA damage, to evaluate the oxidative stress of individuals. In the meantime, many groups have initiated studies of the biological significance of 8-OH-dG, and more than 2000 papers about 8-OH-dG have been published thus far. In this review, we will summarize our resent research progress on oxidative damage.

To clarify the relationship of oxidative stress and body iron status, we detected urinary 8-hydroxydeoxyguanosine (8-OHdG) as a biomarker of oxidative DNA damage, and measured serum ferritin and total iron-binding capacity (TIBC), both reflecting body iron store, on 2507 healthy people aged between 22 and 89 years (males, 1253; females, 1254). The urinary 8-OHdG excretion of males showed almost no change with age, but the excretion of premenopausal females was lower than that of males, whereas postmenopausal females excreted significantly more than males. The values of serum ferritin showed no remarkable change with age in males, but increased gradually in postmenopausal females without iron loss due to bleeding, although the males' values remained higher than those of females at all ages (p < .05). On the other hand, the values of TIBC remained within the narrow limits in males, regardless of age, whereas those of females always stayed at a higher level than the males (p < .05). Conclusively, urinary 8-OHdG correlated with serum ferritin positively and with TIBC inversely, which suggested that body iron status would control the generation of 8-OHdG in vivo. After all, the increase of urinary 8-OHdG excretion in postmenopausal females may be caused by the decrease of body iron loss.

Oxidative stress is reduced by the long-term use of vitamin E-coated dialysis filters. Background Oxidative stress during hemodialysis is thought to promote the progression of vascular complications in hemodialysis patients. The protective role of vitamin E as a lipophilic antioxidant against oxidative stress has been widely investigated. Here we investigated the effects of a vitamin E-coated regenerated cellulose hollow fiber dialyzer (CL-EE) on oxidative stress compared with a polysulfone hollow fiber (CL-PS). Methods For at least three months before beginning the protocol, 10 nondiabetic (NDM) patients (70.0 ± 7.5 years; 6 males and 4 females) and 8 diabetic (DM) patients (65.0 ± 7.4 years; 4 males, 4 females) were dialyzed with CL-PS. After that, we treated all of the patients with CL-EE for six months. Malondialdehyde (MDA), advanced glycation end products (AGEs), and 8-hydroxydeoxyguanosine (8-OHdG) were monitored as biomarkers for oxidative stress at the start and then at one, three, and six months into treatment with CL-EE. Results Serum MDA, AGE, and 8-OHdG levels increased after the hemodialysis with CL-PS. The increase of the biomarkers was completely prevented by a single use of CL-EE. Long-term hemodialysis with CL-EE for six months significantly reduced the basal levels of the oxidant markers at one month for AGE and at six months for 8-OHdG in both DM and NDM patients. Serum MDA was reduced in only DM patients at three months. The improvement of the oxidative stress with CL-EE was more prominent in the DM patients. Conclusions Long-term treatment with CL-EE efficiently improves the oxidative stress associated with hemodialysis and potentially reduces dialysis complications due to oxidative stress.

The urinary levels of 8-hydroxydeoxyguanosine (8-OH-dG), a marker of oxidative DNA damage, of 318 healthy men aged 18 - 58 were measured with high resolution by a newly developed automated high-pressure liquid chromatography (HPLC) system coupled to an electrochemical detector (ECD). The mean 8-OH-dG level (mg / g creatinine) was 4.12 +/- 1.73 (SD). An eleven-fold inter-individual variation was observed. The accuracy of the measurement estimated from the recovery of an added 8-OH-dG standard was 90 - 98%. By univariate analysis, it was found that moderate physical exercise (P = 0.0023) and high body mass index (BMI) (P = 0.0032) reduced the 8-OH-dG level, while physical labor (P = 0.0097), smoking (P = 0.032), and low meat intake (less than once / week) (P = 0.041) increased its level. Based on a multi-regression analysis of the log-transformed values, moderate physical exercise (P = 0.0039), high BMI (P = 0.0099), and age (P = 0.021) showed significant reducing effects on the 8-OH-dG level, while low meat intake (P = 0.010), smoking (P = 0.013), and day-night shift work (P = 0.044) increased its level. These results suggest that many types of life-style factors that either generate or scavenge oxygen radicals may affect the level of oxidative DNA damage of each individual.

We determined the intravitreous level of 8-hydroxydeoxyguanosine (8-OHdG) in diabetic retinopathy (DR) and analyzed the relation between oxidative stress and DR. Vitreous 8-OHdG concentration increased significantly in 18 patients (20 eyes) with DR compared with controls with macular disease. This result suggests that increased oxidative stress is involved in DR.

We measured 8-hydroxy-2-deoxyguanosine (8-OHdG) levels in human leukocytes from healthy donors to evaluate oxidative DNA damage and its correlation with smoking, physical exercise, and alcohol consumption. A significant increase in oxidative DNA damage was induced by cigarette smoke, with the mean level of 8-OHdG being significantly higher in smokers (33.1 +/- 10.6 per 10(6) 2-deoxyguanosine (dG) [mean +/- SE], n = 16) compared with nonsmokers (15.3 +/- 1.8 per 10(6) dG, n = 31) and former smokers (17.8 +/- 1.5 per 10(6) dG, n = 9). The highest values were observed after smoking more than 10 cigarettes per day (41.8 +/- 17.1 per 10(6) dG, n = 9). A large interindividual variation in 8-OHdG levels was observed in all analyzed groups. We also observed a correlation between 8-OHdG levels and age in nonsmokers and former smokers. Neither frequency of physical exercise nor alcohol drinking significantly modified 8-OHdG levels in leukocytes.

The (μ-oxo)(μ-carbonato)diiron(III) complex with H2(tfda) (H2(tfda) = 2-aminomethyl-tetrahydrofuran-N,N-diacetic acid) exhibited high activity for hydroxylation of 2′-deoxygua-nosine in the presence of hydrogen peroxide, giving 8-hydroxydeoxyguanosine, but its hy­ droxylation activity towards other nucleosides such as 2′-deoxyadenosine, adenosine or thym­ idine was found negligible. In the case of the Fe(III)-(ed a) complex (H2(eda) = 2-methoxyethylamine-N,N-diacetic acid), hydroxylation occurred mainly at the sugar site, con­verting 2′-deoxyguanosine to guanosine. Based on the spectroscopic and structural properties of these iron(III) compounds, it seems most likely that an intrinsic active species for hydrox­ylation should be an electrophilic peroxide adduct of the (μ-oxo)diiron(III) core with η1 coordination mode, while the contribution of OH· sides is ruled out.

The 8‐hydroxydeoxyguanosine (8‐OH‐dG) levels in the peripheral parts of human lung tissues were compared between lung cancer patients (n=70) and non‐cancer patient controls (n=15). An increased level of 8‐OH‐dG was observed in the lung cancer group, in both the adenocarcinoma and non‐adenocarcinoma (mainly squamous cell carcinoma) groups, as compared to the non‐cancer control group. This result suggests that reactive oxygen species are partly involved in the induction of lung carcinomas (both adenocarcinoma and non‐adenocarcinoma).

Free radicals and other reactive oxygen species (ROS) are constantly formed in the human body. Free-radical mechanisms have been implicated in the pathology of several human diseases, including cancer, atherosclerosis, malaria, and rheumatoid arthritis and neurodegenerative diseases. For example, the superoxide radical (O2·−) and hydrogen peroxide (H2O2) are known to be generated in the brain and nervous system in vivo, and several areas of the human brain are rich in iron, which appears to be easily mobilizable in a form that can stimulate free-radical reactions. Antioxidant defenses to remove O2·− and H2O2 exist. Superoxide dismutases (SOD) remove O2·− by greatly accelerating its conversion to H2O2. Catalases in peroxisomes convert H2O2 into water and O2 and help to dispose of H2O2 generated by the action of the oxidase enzymes that are located in these organelles. Other important H2O2-removing enzymes in human cells are the glutathione peroxidases. When produced in excess, ROS can cause tissue injury. However, tissue injury can itself cause ROS generation (e.g., by causing activation of phagocytes or releasing transition metal ions from damaged cells), which may (or may not, depending on the situation) contribute to a worsening of the injury. Assessment of oxidative damage to biomolecules by means of emerging technologies based on products of oxidative damage to DNA (e.g., 8-hydroxydeoxyguanosine), lipids (e.g., isoprostanes), and proteins (altered amino acids) would not only advance our understanding of the underlying mechanisms but also facilitate supplementation and intervention studies designed and conducted to test antioxidant efficacy in human health and disease.