DNA oxidative damage in oral cancer: 8-hydroxy-2´-deoxyguanosine immunoexpression assessment.

BACKGROUND: The development and establishment of oral squamous cell carcinoma are confined to carcinogenesis, which involves oxidative stress via oxygen-free radical production as a hydroxyl radical (HO•), considered the most important cause of oxidative damage to basic biomolecules since it targets DNA strands. 8-Hydroxy-2´-deoxyguanosine (8-OHdG) is considered a free radical with a promutagenic capacity due to its ability to pair with adenosine instead of cytosine during replication. MATERIAL AND METHODS: We collected 30 paraffin-embedded tissue samples of OSCC from patients treated between 2013 and 2018. We recorded risk habits, disease stage, disease free survival and death with at least 3 years of follow-up. 8-Hydroxyguanosine was evaluated by immunohistochemistry and subsequently classified as weak-moderate or strong positive expression. Additionally, we noted whether it was expressed in the cytoplasm and/or nucleus. RESULTS: Most of the cases expressed 8-OHdG with a strong intensity (80%). All neoplastic cells were preferentially stained in only the cytoplasm (70.0%), but nuclear positivity was found in 30%, independent of the intensity. Based on the location in the cytoplasm and/or nucleus, tumors >4 cm showed a high frequency (95.5%) of 8-OHdG expression in only the cytoplasm, with a significant difference (p value 0.001). Additionally, overall survival was affected when immunoexpression was present in the cytoplasm and nucleus because all deaths were in this group were statistically significant (p value = 0.001). CONCLUSIONS: All tumors showed DNA oxidative damage, and 8-OHdG was preferentially expressed in the cytoplasm. This finding was associated with tumor size and, when present in the nucleus, might also be related to death.

In vivo toxicity assessment of Remazol Gelb-GR (RG-GR) textile dye in zebrafish embryos/larvae (Danio rerio): Teratogenic effects, biochemical changes, immunohistochemical changes.

Dyes, which are very important for various industries, have very adverse effects on the aquatic environment and aquatic life. However, there are limited studies on the toxic properties of dyes on living things. This research elucidated the sublethal toxicity of acute exposure of the textile dye remazol gelb-GR (RG-GR) using zebrafish embryos and larvae for 96 h. The 96 h-LC50 for RG-GR in zebrafish embryos/larvae was determined to be 151.92 mg/L. Sublethal 96 hpf exposure was performed in RG-GR concentrations (0.5; 1.0; 10.0; 100.0 mg/L) to determine the development of toxicity in zebrafish embryos/larvae. RG-GR dye affected morphological development, and decreased heart rate, hatching, blood flow, and survival rates in zebrafish embryos/larvae. The immunopositivity of 8-hydroxy 2 deoxyguanosine (8-OHdG) in larvae exposed to RG-GR at high concentrations was found to be intense. Depending on the RG-GR dose increase, some biochemical parameters such as glutathione peroxidase (GSH) level, acetylcholinesterase (AChE) activity, catalase (CAT) activities, superoxide dismutase (SOD), and nuclear factor erythroid 2 (Nrf-2) levels were detected to be decreased in larvae, while malondialdehyde (MDA) content, nuclear factor kappa (NF-kB), tumor necrosis factor-α (TNF-α), DNA damage (8-OHdG level), interleukin-6 (IL-6) and apoptosis (Caspase-3) levels were found to be increased. The experimental results revealed that RG-GR dye has high acute toxicity on zebrafish embryo/larvae.

Chronic copper exposure elicit neurotoxic responses in rat brain: Assessment of 8-hydroxy-2-deoxyguanosine activity, oxidative stress and neurobehavioral parameters.

Copper (Cu), one of the essential transition metal acts as a prosthetic group for variety of proteins and metalloenzymes. However, it may be hazardous when administered in excess. Copper induced memory impairment and progression of neurodegenerative diseases have not yet been fully elucidated. The aim of the present study was to investigate the effect of exposure to copper sulphate (10mg/kg and 20mg/kg body weight, daily for 16 weeks) on brain copper concentration, few biochemical parameters indicative of oxidative stress and on different neurobehavioral functions in male Sprague Dawley rats. Copper-administered animals showed significant increase in brain copper concentration and a depleted Ceruloplasmin level. Different neurobehavioral studies revealed impaired memory and motor coordination in copper exposed rat. Spontaneous locomotors activity and depression symptoms were also noted in copper intoxicated rats. 8-hydroxy-2' -deoxyguanosine (8-OHdG) level, one of the predominant forms of free radical-induced oxidative lesions, and has been widely used as a biomarker for oxidative stress, increased in copper treated group. Copper induced oxidative stress in the brain was also evident from the increased lipid per oxidation (LPO) and nitrite level, depletion of reduced glutathione (GSH), and reduced activities of the antioxidant enzymes such as superoxide dismutase (SOD), and catalase. The present study thus suggests a significant correlation between copper induced oxidative stress and changes in neurobehavioral function in rats. The changes were more pronounced in animals exposed to a higher dose of copper (20mg/kg) than the lower dose.

The cost of reproduction in women: Reproductive effort and oxidative stress in premenopausal and postmenopausal American women.

OBJECTIVES: Life history theory predicts a trade-off between female investment in reproduction and somatic maintenance, which can result in accelerated senescence. Oxidative stress has been shown to be a causal physiological mechanism for accelerated aging and a possible contributor to this trade-off. We aimed to test the hypothesis for the existence of significant associations between measures of reproductive effort and the level of oxidative stress biomarkers in premenopausal and postmenopausal American women. METHODS: Serum samples and questionnaire data were collected from 63 premenopausal and postmenopausal women (mean age 53.4 years), controls in the Connecticut Thyroid Health Study, between May 2010 and December 2013. Samples were analyzed for levels of 8-OHdG and Cu/Zn-SOD using immunoassay method. RESULTS: Levels of oxidative damage (8-OHdG) but not oxidative defense (Cu/Zn-SOD) were negatively associated with parity and number of sons in premenopausal women (r = -0.52 for parity, r = -0.52 for number of sons, P < .01). Together, measures of reproductive effort, women's BMI, age, and menopausal status explained around 15% of variance in level of 8-OHdG. No association between reproductive effort characteristics and oxidative damage was found for postmenopausal women. CONCLUSIONS: We found no evidence of a trade-off between somatic maintenance as measured by 8-OHdG and reproductive effort in women from this American population. On the contrary, higher gravidity and parity in premenopausal women was associated with lower damage to cellular DNA caused by oxidative stress. These results highlight the importance of population variation and environmental conditions when testing the occurrence of life-history trade-offs.

Assessment of 8-hydroxy-2-deoxyguanosine activity, gene expression and antioxidant enzyme activity on rainbow trout (Oncorhynchus mykiss) tissues exposed to biopesticide.

The goal of this study was to determinate toxicity mechanism of biopesticide with antioxidant enzymes parameters such as superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) and malondialdehyde (MDA) levels, oxidative DNA damage (8-hydroxy-2-deoxyguanosine (8-OHdG)), transcriptional changes of heat shock protein 70 (HSP70), and cytochromes P4501A (CYP1A), sod, cat, and gpx in liver and gill tissues of Oncorhynchus mykiss. For this aim, plant-based (natural pesticides, azadirachtin (AZA)) and synthetic pesticides (deltamethrin (DLM)) were exposed on the fish at different concentrations (0.0005 and 0.00025ppm of DLM; 0.24 and 0.12ppm of AZA) for 21 days. According to the results of the study, the activity of SOD, CAT and GPx decreased, but malondialdehyde (MDA) level and activity of 8-OHdG increased in the gill and liver of rainbow trout (p<0.05). Additionally sod, cat and gpx were down regulated; HSP70 and CYP1A were up regulated for transcriptional observation. The downwards regulation of antioxidant (sod, cat and gpx) and the upregulation of HSP70 and CYP1A was obvious with doses of AZA or DLM (p<0.05). The findings of this study suggest that biopesticide can cause biochemical and physiological effects in the fish gill and liver by causing enzyme inhibition, an increase in 8-OHdG levels and changes in both transcriptional parameters (sod, cat, gpx, HSP70 and CYP1A). We found that excessive doses of plant-based pesticide are nearly as toxic as chemical ones for aquatic organisms. Moreover, 8-OHdG, HSP70 and CYP1A used as a biomarker to determinate toxicity mechanism of biopesticide in aquatic environment.

Assessment of sperm nuclear quality after in vitro maturation of fresh or frozen/thawed mouse pre-pubertal testes.

STUDY QUESTION: Is nuclear quality of in vitro generated spermatozoa from fresh or frozen/thawed pre-pubertal mouse testes similar to that of their in vivo counterparts? SUMMARY ANSWER: The production of spermatozoa with aneuploidy, DNA fragmentation or chromatin condensation defects was not significantly increased in organotypic cultures compared to in vivo controls. WHAT IS KNOWN ALREADY: Although murine spermatozoa have been produced in vitro from pre-pubertal testes, their nuclear DNA integrity has never been investigated. STUDY DESIGN, SIZE, DURATION: Fresh and frozen/thawed testicular fragments from 6 to 7 days postpartum (dpp) mice were cultured for 30 days. Testicular tissues were frozen by controlled slow freezing (CSF) or solid surface vitrification (SSV). In total, 30 fresh, 30 CSF, 30 SSV testes were used for in vitro maturation and 6 testes from 36 to 37 dpp mice were used as in vivo controls. PARTICIPANTS/MATERIALS, SETTING, METHODS: Murine spermatozoa were extracted from pooled in vitro cultured testicular fragments and from in vivo controls. Sperm aneuploidy was analyzed by fluorescence in situ hybridization (FISH), DNA fragmentation by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling, chromatin condensation by aniline blue staining, telomere length and number by quantitative FISH, DNA oxidation by immunocytochemical detection of 8-hydroxy-2'-deoxyguanosine (8-OHdG). Because of the low spermatogenic yield in cultures, a hundred spermatozoa extracted from pooled tissues were examined and compared to their in vivo counterparts. MAIN RESULTS AND THE ROLE OF CHANCE: Most of spermatozoa generated in vitro and in vivo were haploid, contained unfragmented DNA and normally condensed chromatin. A similar proportion of spermatozoa with aneuploidy, DNA fragmentation or chromatin condensation defects was found in cultures and in vivo. No significant difference in telomere length was found within the nuclei of in vitro and in vivo generated spermatozoa. However, the number of telomere spots was lower in gametes obtained from cultures of fresh, CSF and SSV testes than in their natural counterparts (P < 0.01). Moreover, the proportion of spermatozoa containing 8-OHdG was significantly increased in frozen/thawed tissues in comparison to fresh tissues and in vivo controls (P < 0.05). LARGE SCALE DATA: None. LIMITATIONS REASONS FOR CAUTION: Further studies will be needed to enhance the production of spermatozoa in organotypic cultures while preserving their quality, to investigate epigenetic modifications and embryonic development. WIDER IMPLICATIONS OF THE FINDINGS: This is the first study comparing the nuclear quality of in vitro and in vivo generated murine spermatozoa. The organotypic culture system will have to be adapted for human tissue and extensive analyses of human gamete quality will have to be performed before potential clinical applications can be envisaged. STUDY FUNDING AND COMPETING INTEREST(S): This work was supported by Rouen University Hospital, Ligue contre le Cancer, Agence de la Biomédecine, Association Laurette Fugain, France Lymphome Espoir, and co-supported by European Union and Région Normandie. Europe gets involved in Normandie with European Régional Development Fund (ERDF). The authors declare that they have no conflict of interest.

Assessment of the proliferation status of glioblastoma cell and tumour tissue after nanoplatinum treatment.

Glioblastoma is one of the most frequent primary brain tumours of the central nervous system, with a poor survival time. With inefficient chemotherapy, it is urgent to develop new strategies for tumour therapy. The present approach is based on the inhibition of cell proliferation using platinum nanoparticles (NP-Pt). The aim of the study was to evaluate and compare the antiproliferative properties of NP-Pt and cisplatin against U87 and U118 glioma cell lines and U87 tumour tissue. NP-Pt and cisplatin were incubated with U87 and U118 glioma cells or administered directly into glioma tumour tissue. Cell morphology, the level of DNA synthesis, the migration of cells, protein expression levels of proliferating cell nuclear antigen (PCNA) and the level of DNA oxidation in glioma tumours were investigated. The results showed that NP-Pt treatment of U87 and U118 glioma cells decreased the level of DNA synthesis and the migration of cancer cells but also downregulated the level of PCNA protein expression in tumour tissue. Furthermore, NP-Pt caused oxidative DNA damage in tumour tissue to a higher degree than cisplatin. Consequently, NP-Pt can be considered as an effective inhibitor of glioblastoma tumour cell proliferation. However, the mechanism of action and potential side effects need to be elucidated further.

Assessment of Pulmonary Toxicity Induced by Inhaled Toner with External Additives.

We investigated the harmful effects of exposure to a toner with external additives by a long-term inhalation study using rats, examining pulmonary inflammation, oxidative stress, and histopathological changes in the lung. Wistar rats were exposed to a well-dispersed toner (mean of MMAD: 2.1 µm) at three mass concentrations of 1, 4, and 16 mg/m3 for 22.5 months, and the rats were sacrificed after 6 months, 12 months, and 22.5 months of exposure. The low and medium concentrations did not induce statistically significant pulmonary inflammation, but the high concentration did, and, in addition, a histopathological examination showed fibrosis in the lung. Although lung tumor was observed in one sample of high exposure for 22.5 months, the cause was not statistically significant. On the other hand, a persistent increase in 8-OHdG was observed in the high exposure group, indicating that DNA damage by oxidative stress with persistent inflammation leads to the formation of tumorigenesis. The results of our studies show that toners with external additives lead to pulmonary inflammation, oxidative stress, and fibrosis only at lung burdens beyond overload. These data suggest that toners with external additives may have low toxicity in the lung.

Neurotoxic responses in brain tissues of rainbow trout exposed to imidacloprid pesticide: Assessment of 8-hydroxy-2-deoxyguanosine activity, oxidative stress and acetylcholinesterase activity.

The extensive use of imidacloprid, a neonicotinoid insecticide, causes undesirable toxicity in non-targeted organisms including fish in aquatic environments. We investigated neurotoxic responses by observing 8-hydroxy-2-deoxyguanosine (8-OHdG) activity, oxidative stress and acetylcholinesterase (AChE) activity in rainbow trout brain tissue after 21 days of imidacloprid exposure at levels of (5 mg/L, 10 mg/L, 20 mg/L). The obtained results indicated that 8-OHdG activity did not change in fish exposed to 5 mg/L of imidacloprid, but 10 mg/L and 20 mg/L of imidacloprid significantly increased 8-OHdG activity compared to the control (p < 0.05). An immunopositiv reaction to 8-OHdG was detected in brain tissues. The brain tissues indicated a significant increase in antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)) compared to the control and there was a significant increase in malondialdehyde (MDA) levels (p < 0.05). High concentrations of imidacloprid caused a significant decrease in AChE enzyme activity (p < 0.05). These results suggested that imidacloprid can be neurotoxic to fish by promoting AChE inhibition, an increase in 8-OHdG activity and changes in oxidative stress parameters. Therefore, these data may reflect one of the molecular pathways that play a role in imidacloprid toxicity.

Assessment of genotoxicity of pyrethrin in cultured human lymphocytes.

Pyrethrin is an insecticide that is obtained from the Chrysanthemum flower (Pyrethrum). In this study, we examined the genotoxic effects of pyrethrin on cultured human lymphocytes using sister chromatid exchanges (SCEs) and 8-hydroxy deoxyguanosine (8-OHdG) assays. Cultures were treated with different concentrations of pyrethrin (25, 50, and 100 µg/mL), which was dissolved in in dimethyl sulfoxide (DMSO). The results showed that treatment of cultured lymphocytes with pyrethrin at 50 µg/mL and 100 µg/mL induced significant elevation in SCEs (p < 0.05). In addition, the 100 µg/mL concentration significantly affected both mitotic and proliferative indices (p < 0.05). Finally, pyrethrin induced significant elevation in the oxidative stress marker 8-OHdG in a dose-dependent manner (p < 0.001). In conclusion, the results suggest that pyrethrin is genotoxic as measured by two independent assays on genetic toxicity.

In Vitro Toxicological Assessment of Magnesium Oxide Nanoparticle Exposure in Several Mammalian Cell Types.

Worldwide researchers have rising concerns about magnesium-based materials, especially magnesium oxide (MgO) nanaoparticles, due to increasing usage as promising structural materials in various fields including cancer treatment. However, there is a serious lack of information about their toxicity at the cellular and molecular levels. In this study, the toxic potentials of MgO nanoparticles were investigated on liver (HepG2), kidney (NRK-52E), intestine (Caco-2), and lung (A549) cell lines. For the toxicological assessment, the following assays were used: the particle characterization by transmission electron microscopy, the determination of cellular uptake by inductively coupled plasma-mass spectrometry, MTT and neutral red uptake assays for cytotoxicity, comet assay for genotoxicity, and the determination of malondialdehyde (MDA), 8-hydroxydeoxyguanosine, protein carbonyl, and glutathione levels by enzyme-linked immune sorbent assays for the potential of oxidative damage and annexin V-fluorescein isothiocyanate (FITC) apoptosis detection assay with propidium iodide (PI) for apoptosis. Magnesium oxide nanoparticles were taken up by the cells depending on their concentration and agglomeration/aggregation potentials. Magnesium oxide nanoparticles induced DNA (≤14.27 fold) and oxidative damage. At a concentration of ≥323.39 µg/mL, MgO nanoparticles caused 50% inhibition in cell viability by 2 different cytotoxicity assays. The cell sensitivity to cytotoxic and genotoxic damage induced by MgO nanoparticles was ranked as HepG2 < A549 < Caco-2 < NRK-52E. Although it was observed that MgO nanoparticles induced apoptotic effects on the cells, apoptosis was not the main cell death. DNA damage, cell death, and oxidative damage effects of MgO nanoparticles should raise concern about the safety associated with their applications in consumer products.

Toxicity assessment of hydroxyapatite nanoparticles in rat liver cell model in vitro.

Hydroxyapatite nanoparticles (HAP NPs) are widely used for preparations of biomedical and biotechnological fields such as drug delivery, gene therapy, and molecular imaging. However, the current toxicological knowledge about HAP NPs is relatively limited. The present study was designed to investigate the toxicity potentials of various concentrations (0-1000 µg cm(-2)) of HAP NPs in cultured primary rat hepatocytes. Cell viability was detected by 3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) release, while total antioxidant capacity (TAC) and total oxidative stress (TOS) levels were determined to evaluate the oxidative injury. The DNA damage was also analyzed via scoring liver micronuclei rates and determining 8-oxo-2-deoxyguanosine (8-OH-dG) levels. The results of MTT and LDH assays showed that the higher concentrations of dispersed HAP NPs (300, 500, and 1000 µg cm(-2)) decreased cell viability. Also, HAP NPs increased TOS (500 and 1000 µg cm(-2)) levels and decreased TAC (300, 500, and 1000 µg cm(-2)) levels in cultured hepatocytes. On the basis of increasing doses, the NPs as depending on dose caused significant increases of the number of micronucleated hepatocytes and 8-OH-dG levels as compared to control culture. Furthermore, the highest concentration of HAP NPs (1000 µg cm(-2)) exhibited cytotoxic activity. Based on these results, HAP NPs have a dose-dependent toxic effect in rat hepatocytes. Further extensive research in this field is promising and reasonable.

Assessment of genotoxicity of waterpipe smoking using 8-OHdG biomarker.

Waterpipe tobacco smoking is increasing in popularity, particularly among young adults. This popularity is related to the lack knowledge regarding the health effects of waterpipe smoking. In this study, we examined the genotoxicity of waterpipe smoking using an 8-hydroxy deoxyguanosine (8-OHdG) assay. Genotoxicity was evaluated in the saliva, urine, and serum of 66 waterpipe adult smokers and 46 healthy nonsmokers. The level of addiction to waterpipe smoking was evaluated using the Lebanon Waterpipe Dependence Scale-11. Levels of 8-OHdG in the samples were measured using commercially available enzyme-linked immunosorbent assays. Levels of 8-OHdG in the saliva (52,430 ± 2923 vs 48,430 ± 4189 pg/mL), urine (2815 ± 312 vs 2608 ± 180 pg/mL), and serum (19,720 ± 202 vs 19,670 ± 254 pg/mL) were similar between waterpipe smokers and nonsmokers (P > 0.05). In addition, no correlations were found between dependence score and levels of 8-OHdG in all sample types. In conclusion, 8-OHdG is not a good biomarker for genotoxic effect of waterpipe smoking.

Assessment of the reproductive toxicity of inhalation exposure to ethyl tertiary butyl ether in male mice with normal, low active and inactive ALDH2.

No data are available regarding aldehyde dehydrogenase 2 (ALDH2) polymorphisms related to the reproductive toxicity possibly caused by ethyl tertiary butyl ether (ETBE). In this study, two inhalation experiments were performed in Aldh2 knockout (KO), heterogeneous (HT) and wild type (WT) C57BL/6 male mice exposed to ETBE, and the data about general toxicity, testicular histopathology, sperm head numbers, sperm motility and sperm DNA damage were collected. The results showed that the 13-week exposure to 0, 500, 1,750 and 5,000 ppm ETBE significantly decreased sperm motility and increased levels of sperm DNA strand breaks and 8-hydroxy-deoxyguanosine in both WT and KO mice, the effects were found in 1,750 and 5,000 ppm groups of WT mice, and all of the three exposed groups of KO mice compared to the corresponding control; furthermore, ETBE also caused decrease in the relative weights of testes and epididymides, the slight atrophy of seminiferous tubules of testis and reduction in sperm numbers of KO mice exposed to ≥500 ppm. In the experiment of exposure to lower concentrations of ETBE (0, 50, 200 and 500 ppm) for 9 weeks, the remarkable effects of ETBE on sperm head numbers, sperm motility and sperm DNA damage were further observed in KO and HT mice exposed to 200 ppm ETBE, but not in WT mice. Our findings suggested that only exposure to high concentrations of ETBE might result in reproductive toxicity in mice with normal active ALDH2, while low active and inactive ALDH2 enzyme significantly enhanced the ETBE-induced reproductive toxicity in mice, even exposed to low concentrations of ETBE, mainly due to the accumulation of acetaldehyde as a primary metabolite of ETBE.

Assessment of oxidant/antioxidant status in saliva of cell phone users.

Hazardous health effects resulting from exposure to radiofrequency electromagnetic radiation (RF-EMR) emitted from cell phones have been reported in the literature. However, the cellular and molecular targets of RF-EMR are still controversial. The aim of this study was to examine the oxidant/antioxidant status in saliva of cell phone users. Saliva samples collected before using a cell phone as well as at the end of 15 and 30 min calls were tested for two commonly used oxidative stress biomarkers: malondialdehyde (MDA) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-Oxo-dG). The 8-oxo-dG levels were determined by enzyme-linked immunosorbent (ELISA) competitive assay, while the MDA levels were measured using the OxiSelect MDA adduct ELISA Kit. The antioxidant capacity of the saliva was evaluated using the oxygen radical absorption capacity (ORAC) and the hydroxyl radical averting capacity (HORAC) assays according to the manufacture instructions. The mean 8-oxo-dG and the Bradford protein concentrations (ng/ml and mg/ml, respectively) peaked at 15 min. The levels of HORAC, ORAC and MDA progressively increased with time and reached maximum at 30 min. However, there was no significant effect of talking time on the levels of 8-OxodG and MDA. Similarly, there was no statistically significant effect of talking time on the oxygen and hydroxyl radicals averting capacities, (ORAC) and (HORAC), respectively. These findings suggest that there is no relationship between exposure to radio frequency radiation (RFR) and changes in the salivary oxidant/antioxidant profile.

In-vitro assessment of oxidative stress generated by orthodontic archwires.

INTRODUCTION: Several metals undergo redox cycling, producing free radicals and generating oxidative stress. The purpose of this study was to investigate in-vitro oxidative stress of orthodontic archwires made of various alloys. METHODS: Mouse fibroblast cells L929 were exposed to 6 types of archwires, and the concentration of the oxidative stress marker 8-hydroxy-2'-deoxyguanosine in DNA was evaluated. Trypan blue dye was used in the determination of cell viability and numbers. RESULTS: Standard nickel-titanium archwires generated the highest oxidative stress, significantly higher than all other wires and the controls (P <0.05), and coated nickel-titanium, copper-nickel-titanium, and cobalt-chromium were lower than nickel-titanium (P <0.05), but higher than titanium-molybdenum and the negative and absolute controls (P <0.05). Titanium-molybdenum and stainless steel generated the lowest stress. Nickel-titanium induced the lowest viability, lower than the negative and absolute controls and all other wires (P <0.05) except titanium-molybdenum. Stainless steel showed the highest viability. Nickel-titanium produced the highest inhibition of cell growth, higher than all samples (P <0.05) except the positive control and cobalt-chromium. The lowest inhibition was observed in stainless steel and titanium-molybdenum, lower than nickel-titanium, cobalt-chromium, and the positive control (P <0.05). CONCLUSIONS: All orthodontic archwires generate oxidative stress in vitro. Stainless steel archwires have the highest and nickel-titanium the lowest biocompatibility.

Double-face activity of resveratrol in voluntary runners: assessment of DNA damage by comet assay.

Voluntary runners are subjected to a massive increase in reactive oxygen/nitrogen species production, which can promote different oxidative stress-related diseases such as premature aging, neurodegenerative disorders, and cancer. The aims of this work were to evaluate the following in peripheral blood cells of voluntary runners: (i) DNA status; (ii) susceptibility to the in vitro insult induced by hydrogen peroxide (H(2)O(2)) as a breaking agent; (iii) capabilities of 3,5,4'-trihydroxystilbene (RESV) in counteracting DNA damage. Twenty-five male voluntary runners were compared with 20 sedentary men, as age-matched controls, and DNA status was evaluated with different versions of comet assay: alkaline, neutral, and Fpg enzyme-modified version to measure 8-OH-deoxyguanosine (8-oxo-dG) levels. The H(2)O(2) and/or RESV treatments were performed directly on agarose-embedded cells (atypical comet assay). The results evidenced DNA damage and levels of 8-oxo-dG higher in runners than in sedentary control subjects. The runners' DNA was more prone to the in vitro-induced oxidative insult (200 µM H(2)O(2)) than that of the control group. Resveratrol (100 µM), depending on the individual basal DNA status, was able to switch from antioxidant to pro-oxidant. Our results, on the one hand, validated the proposed in vitro experimental protocol in order to measure individual DNA status. On the other hand, our data point out the importance of monitoring the athletes' redox status before subjecting them to dietary supplementation treatment.

Assessment of 8-oxo-7, 8-dihydro-2'-deoxyguanosine and malondialdehyde levels as oxidative stress markers and antioxidant status in non-small cell lung cancer.

OBJECTIVE: The present investigation was taken up to evaluate the 8-oxo-7,8-dihydro-2'-deoxyguanosine and malondialdehyde as markers of oxidative stress, the levels of antioxidants and the correlations between these oxidative stress markers and antioxidants in lung cancer patients. METHODS: The study included 222 patients (158 men and 64 women, age ranging from 32 to 85 years) and 207 control subjects (153 men and 54 women, aged 30-80 years) for the analysis of urinary excretion of 8-oxodG using an ELISA assay, plasma malondialdehyde using spectrophotometer and red cell Cu-Zn SOD and GPx activities by kit methods. RESULTS: The levels of 8-oxodG and malondialdehyde were significantly higher (p < 0.001) and red cell superoxide dismutase and glutathione peroxidase activities (p < 0.001) were significantly lower in lung cancer patients than in controls. There was a significantly positive correlation between 8-oxodG and malondialdehyde (r=0.912, p < 0.001) and a negative correlation between 8-oxodG and antioxidants. CONCLUSIONS: Our results demonstrate that an increased rate of oxidative stress might play a role in the pathogenesis of lung cancer as evidenced by a failure in the oxidant/antioxidant balance in favour of lipid peroxidation and DNA damage.

Genetic polymorphisms of glutathione S-transferase M1, T1, and P1, and the assessment of oxidative damage in infertile men with varicoceles from northwestern China.

Our objective was to investigate the genetic polymorphisms of the glutathione S-transferase M1, T1, and P1 genes (GSTM1, GSTT1, and GSTP1) and to assess the oxidative damage in infertile men with varicoceles from northwestern China. A total of 65 infertile men with varicoceles and 30 controls were included in the study. Multiplex polymerase chain reaction and polymerase chain reaction-restriction fragment length polymorphism analyses were used to identify the genotypes. Sperm DNA damage was assessed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL). The levels of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) were measured by high-performance liquid chromatography with electrochemical detection. The activities of malondialdehyde (MDA) and nitric oxide (NO), and the total antioxidant capacity (TAC) were detected by spectroscopic analysis, and sperm characteristics were measured using computer-assisted semen analysis. The frequencies of the GSTM1, GSTT1, and GSTP1 genotypes were not significantly different between the control and patient groups (P > .05). The percentage of TUNEL-positive sperm and the levels of 8-OH-dG, MDA, and NO were higher but the sperm concentration and motility and the TAC were lower in the patients with the GSTM1, GSTT1, and GSTM1/T1 null genotypes than those in the patients with the GSTM1, GSTT1, and GSTM1/T1 present genotypes (P < .05). However, no significant differences were observed between the GSTP1 A/A and A/G+G/G genotypes (P > .05). Our results suggest that the GSTM1 and GSTT1 null genotypes may predispose sperm to increased oxidative damage in infertile men with varicoceles; however, GSTP1 allelic variation was not significantly different between the patient and control groups in this study.

Assessment of oxidative stress-induced DNA damage by immunoflourescent analysis of 8-oxodG.

Oxidative stress refers to the imbalance between the generation of reactive oxygen species (ROS) and their scavenging by the inherent antioxidant defenses of the cell. The abnormal accumulation of ROS is the underlying pathology in a variety of human diseases such as neurodegenerative phenomena, inflammatory diseases, metabolic disorders, and cancer. The mechanism by which abnormal accumulation of ROS contributes to pathological conditions involves damage or oxidative modification of biomolecules, such as nucleotides, lipids, and proteins. One of the most common targets of ROS is DNA, modifications of which have been associated with cellular transformation and genome instability. There are a number of experimental strategies to assess oxidative modification of DNA bases, such as chromatography-based assays and indirect immunofluorescence. While the former provide quantitative assessment of oxidative modification, the latter is a much simpler assay for qualitative determination of DNA base modification in very small sample sizes. Here, we present a brief background of the various methodologies for the assessment of a specific oxidative DNA modification, 8oxodG, and present a more detailed account of the indirect immunofluorescence assay.