8-hydroxyguanosine and 3-nitrotyrosine

Colorectal cancer as well as colorectal surgery is associated with increased oxidative stress through different mechanisms. In this study the levels of different oxidative stress markers were comparatively assessed in patients who underwent laparoscopic or conventional resection for colorectal cancer.. Sixty patients with colorectal cancer were randomly assigned to undergo laparoscopic (LS) or open surgery (OS). Lipid, protein, RNA, and nitrogen damage was investigated by measuring serum 8-isoprostanes (8-epiPGF2α), protein carbonyls (PC), 8-hydroxyguanosine (8-OHG), and 3-nitrotyrosine (3-NT), respectively. The primary end point of the study was to analyze and compare serum levels of the oxidative stress markers between the groups.. Postoperative serum levels of 8-epiPGF2α, 3-NT, and 8-OHG were significantly lower in the LS group at 24 h after surgery (p < 0.05). At 6 h postoperatively, the levels of 8-epiPGF2α and 3-NT were significantly lower in the LS group (p < 0.05). No difference in the levels of PC was found between the two groups at any time point. In the OS group, postoperative levels of 8-epiPGF2α were significantly lower than the preoperative values (p < 0.01). In the LS group, the postoperative values of 8-epiPGF2α, 3-NT, and 8-OHG were significantly lower than the preoperative values (p < 0.05).. Laparoscopic surgery for colorectal cancer is associated with lower oxidative stress compared to open surgery. 8-epiPGF2α was the most suitable marker for readily defining the oxidative status in patients who underwent surgery for colorectal cancer.

Topics: Aged; Analysis of Variance; Biomarkers; Colectomy; Colorectal Neoplasms; Dinoprost; Double-Blind Method; Female; Guanosine; Humans; Laparoscopy; Male; Oxidative Stress; Postoperative Period; Protein Carbonylation; Tyrosine

Markers of oxidative stress and inflammation were analysed in the exhaled breath condensate (EBC) and urine samples of 14 workers (mean age 43  ±  7 years) exposed to iron oxide aerosol for an average of 10  ±  4 years and 14 controls (mean age 39  ±  4 years) by liquid chromatography-electrospray ionization-mass spectrometry/mass spectrometry (LC-ESI-MS/MS) after solid-phase extraction. Aerosol exposure in the workplace was measured by particle size spectrometers, a scanning mobility particle sizer (SMPS) and an aerodynamic particle sizer (APS), and by aerosol concentration monitors, P-TRAK and DustTRAK DRX. Total aerosol concentrations in workplace locations varied greatly in both time and space. The median mass concentration was 0.083 mg m(-3) (IQR 0.063-0.133 mg m(-3)) and the median particle concentration was 66 800 particles cm(-3) (IQR 16,900-86,900 particles cm(-3)). In addition, more than 80% of particles were smaller than 100 nm in diameter. Markers of oxidative stress, malondialdehyde (MDA), 4-hydroxy-trans-hexenale (HHE), 4-hydroxy-trans-nonenale (HNE), 8-isoProstaglandin F2α (8-isoprostane) and aldehydes C6-C12, in addition to markers of nucleic acid oxidation, including 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), 5-hydroxymethyl uracil (5-OHMeU), and of proteins, such as o-tyrosine (o-Tyr), 3-chlorotyrosine (3-ClTyr), and 3-nitrotyrosine (3-NOTyr) were analysed in EBC and urine by LC-ESI-MS/MS. Almost all markers of lipid, nucleic acid and protein oxidation were elevated in the EBC of workers comparing with control subjects. Elevated markers were MDA, HNE, HHE, C6-C10, 8-isoprostane, 8-OHdG, 8-OHG, 5-OHMeU, 3-ClTyr, 3-NOTyr, o-Tyr (all p  <  0.001), and C11 (p  <  0.05). Only aldehyde C12 and the pH of samples did not differ between groups. Markers in urine were not elevated. These findings suggest the adverse effects of nano iron oxide aerosol exposure and support the utility of oxidative stress biomarkers in EBC. The analysis of urine oxidative stress biomarkers does not support the presence of systemic oxidative stress in iron oxide pigment production workers.

Topics: Adult; Aldehydes; Biomarkers; Breath Tests; Dinoprost; Ferric Compounds; Guanosine; Humans; Male; Malondialdehyde; Middle Aged; Nanoparticles; Oxidative Stress; Tandem Mass Spectrometry; Tyrosine

The role of nitric oxide (NO) in the human pancreas and in pancreatitis still remains controversial. Furthermore, conflicting conclusions have been reached by different laboratories about the localization of the NO-generating enzyme (NO synthase, NOS) in the pancreas. Here, we investigated the co-expression of NOS with enzymes involved in regulation of NO signalling in the normal human pancreas and in pancreatitis. We found that the whole NO signalling machinery was up-regulated in pancreatitis, especially within the exocrine compartment. Furthermore, the exocrine parenchymal cells revealed higher levels of oxidative stress markers, nitrotyrosine and 8-hydroxyguanosine, in pancreatitis, which reflects the exceptional susceptibility of the exocrine parenchyma to oxidative stress. This study provides a direct link between oxidative stress and the enzymatic control of the NO bioavailability at the cellular level and endows with further insight into fundamental mechanisms underlying pancreatic disorders associated with disruptions in the L-arginine-NO-cGMP signalling enzyme cascade.

Topics: Aged; Arginine; Biomarkers; Case-Control Studies; Cyclic GMP; Female; Fluorescent Antibody Technique; Guanosine; Humans; Immunoenzyme Techniques; Male; Middle Aged; Nitric Oxide; Nitric Oxide Synthase; Oxidative Stress; Pancreas; Pancreatitis; Signal Transduction; Tyrosine

Hydrogen gas has been demonstrated to neutralize free radicals and reduce oxidative stress recently. Our objective was to determine the therapeutic effect of H2 inhalation and its antioxidative activity on early brain injury after subarachnoid hemorrhage.. Controlled in vivo laboratory study.. Animal research laboratory.. One hundred thirty-seven adult male Sprague-Dawley rats weighing 280-350 g.. Subarachnoid hemorrhage was induced by endovascular perforation method in rats. Subarachnoid hemorrhage rats were treated with 2.9% hydrogen gas inhaled for 2 hrs after perforation. At 24 and 72 hrs, mortality, body weight, neurologic deficits, and brain water content were assessed. Blood-brain barrier permeability and apoptosis were also measured at 24 hrs. To investigate the antioxidative activity of hydrogen gas, the expression of malondialdehyde, nitrotyrosine, and 8-hydroxyguanosine, which are oxidative markers of lipid, protein, and DNA damage, respectively, were measured at 24 hrs.. Hydrogen gas significantly alleviated brain edema and blood-brain barrier disruption, reduced apoptosis, and improved neurologic function at 24 hrs but not 72 hrs after subarachnoid hemorrhage. These effects were associated with the amelioration of oxidative injury of lipid, protein, and DNA.. Hydrogen gas could exert its neuroprotective effect against early brain injury after subarachnoid hemorrhage by its antioxidative activity.

Topics: Administration, Inhalation; Animals; Antioxidants; Apoptosis; Blood-Brain Barrier; Brain; Brain Chemistry; Brain Injuries; Guanosine; Hydrogen; Lipid Peroxidation; Male; Malondialdehyde; Oxidative Stress; Rats; Rats, Sprague-Dawley; Subarachnoid Hemorrhage; Tyrosine; Water

Ethanol exposure during pregnancy may result in fetal alcohol syndrome (FAS). The mechanism by which this occurs is unknown. Recent studies in several organ systems, including the placenta, suggest that oxidative stress is involved. In this study we investigated the presence and levels of three oxidative stress markers in placental villous tissue exposed to ethanol.. Villous tissues from normal placentas were perfused with Dulbeco's modified Eagle's medium (DMEM) with HEPES buffer, sodium bicarbonate, and glucose at pH 7.4. After stabilization, 100 mM ethanol was added to the perfusate. After 2 hours of perfusion, the tissue was removed, fixed and stained for nitrotyrosine, 4-hydroxy-2-nonenal (4HNE) and 8-hydroxyguanosine (8-OHDG). Staining within the trophoblasts was quantified with densitometry.. Nitrotyrosine and 4HNE immunostaining was seen in the trophoblasts. 4HNE was also seen in the stroma. In contrast, 8-OHDG was seen only in the stroma and endothelial cells in the fetal circulation. Ethanol exposure significantly increased nitrotyrosine levels in the trophoblasts beyond levels in the control tissue. Nitrotyrosine and 8-OHDG levels were also increased in stroma.. Within the placental villi, markers of oxidative stress are present in the trophoblasts and stroma after a short period of ethanol exposure. There is an increase in oxidative stress, primarily involving the nitric oxide pathway, in the trophoblasts as well as DNA damage in the stroma. Lipid peroxidation is not acutely changed in our 2-hour exposure window.

Topics: Aldehydes; Biomarkers; Ethanol; Female; Guanosine; Humans; Oxidative Stress; Placenta; Pregnancy; Trophoblasts; Tyrosine

Apoptosis of retinal capillary cells is an early event in the pathogenesis of retinopathy in diabetes, and oxidative stress has been linked to accelerated apoptosis of retinal capillary cells. Mitochondria are the major endogenous source of superoxide, and superoxide is considered to be a causal link between elevated glucose and the major biochemical pathways postulated to be involved in the development of vascular complications in diabetes. The purpose of the present study is to determine the role of mitochondrial superoxide dismutase (MnSOD) in the development of diabetic retinopathy.. The effect of overexpression of MnSOD on glucose-induced endothelial cell oxidative stress, nitrosative stress, and apoptosis was determined by using bovine retinal endothelial cells. Furthermore, the effect of diabetes in rats (11 months' duration) on the activity and the mRNA expression of retinal MnSOD were also determined.. MnSOD activity in the nontransfected control retinal endothelial cells was 20% compared with the total SOD activity and was increased to 60% in the MnSOD-transfected cells. MnSOD overexpression prevented a glucose-induced increase in oxidative stress (8-hydroxy guanosine levels), nitrosative stress (nitrotyrosine formation), and apoptosis of retinal endothelial cells. MnSOD enzyme activity and its mRNA were decreased significantly in the retina obtained from the diabetic rats, and these abnormalities were prevented by long-term lipoic acid therapy.. The results of this study suggest a protective role for MnSOD in retinal capillary cell death and, ultimately, in the pathogenesis of retinopathy in diabetes. Understanding the role of MnSOD to modify the course of retinopathy could elucidate important molecular targets for future pharmacological interventions.

Topics: Animals; Apoptosis; Cattle; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Endothelium, Vascular; Gene Expression Regulation, Enzymologic; Guanosine; Mitochondria; Nitrosation; Oxidative Stress; Rats; Rats, Wistar; Retina; Retinal Vessels; RNA, Messenger; Superoxide Dismutase; Transfection; Tyrosine

Severe pulmonary hypertension (PH) occurs in a primary or "unexplained" form and in a group of secondary forms associated with a number of diseases. Because the lung tissue from patients with severe PH demonstrates complex vascular lesions, which contain inflammatory cells, we wondered whether the lung tissue from patients with severe PH was "under oxidative stress." We used immunohistochemistry to localize nitrotyrosine and 8-hydroxy guanosine in the lung tissue sections from patients with primary and secondary PH. In some lung tissue extracts, the eicosanoid metabolites 5-oxo-eicosatetraenoic acid, leukotriene B4 5-hydroxyeicosatetraenoic acid (HETE), 12-HETE, and 15-HETE were measured using mass spectroscopy, and superoxide dismutase amount and activity were measured. Nitrotyrosine expression was ubiquitous in all PH lungs, and 5-oxo-eicosatetraenoic acid and HETE levels were elevated in the lungs of patients with severe PH but not in those lungs that were from the patients with severe PH treated chronically with prostacyclin. We conclude that indeed the lungs from patients with severe PH are under oxidative stress and that chronic prostacyclin infusion has an antiinflammatory effect on the lung tissue.

Topics: Arachidonic Acids; Guanosine; Humans; Hypertension, Pulmonary; Lung; Oxidative Stress; Severity of Illness Index; Superoxide Dismutase; Tyrosine

The finding that oxidative damage, including that to nucleic acids, in Alzheimer's disease is primarily limited to the cytoplasm of susceptible neuronal populations suggests that mitochondrial abnormalities might be part of the spectrum of chronic oxidative stress of Alzheimer's disease. In this study, we used in situ hybridization to mitochondrial DNA (mtDNA), immunocytochemistry of cytochrome oxidase, and morphometry of electron micrographs of biopsy specimens to determine whether there are mitochondrial abnormalities in Alzheimer's disease and their relationship to oxidative damage marked by 8-hydroxyguanosine and nitrotyrosine. We found that the same neurons showing increased oxidative damage in Alzheimer's disease have a striking and significant increase in mtDNA and cytochrome oxidase. Surprisingly, much of the mtDNA and cytochrome oxidase is found in the neuronal cytoplasm and in the case of mtDNA, the vacuoles associated with lipofuscin. Morphometric analysis showed that mitochondria are significantly reduced in Alzheimer's disease. The relationship shown here between the site and extent of mitochondrial abnormalities and oxidative damage suggests an intimate and early association between these features in Alzheimer's disease.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Alzheimer Disease; Cerebellum; Child; Child, Preschool; DNA, Mitochondrial; Electron Transport Complex IV; Frontal Lobe; Guanosine; Hippocampus; Humans; Immunohistochemistry; In Situ Hybridization; Microscopy, Electron; Middle Aged; Mitochondria; Neurons; Oxidative Stress; Temporal Lobe; Tyrosine

Recently, we demonstrated a significant increase of an oxidized nucleoside derived from RNA, 8-hydroxyguanosine (8OHG), and an oxidized amino acid, nitrotyrosine in vulnerable neurons of patients with Alzheimer disease (AD). To determine whether oxidative damage is an early- or end-stage event in the process of neurodegeneration in AD, we investigated the relationship between neuronal 8OHG and nitrotyrosine and histological and clinical variables, i.e. amyloid-beta (A beta) plaques and neurofibrillary tangles (NFT), as well as duration of dementia and apolipoprotein E (ApoE) genotype. Our findings show that oxidative damage is quantitatively greatest early in the disease and reduces with disease progression. Surprisingly, we found that increases in A beta deposition are associated with decreased oxidative damage. These relationships are more significant in ApoE epsilon4 carriers. Moreover, neurons with NFT show a 40%-56% decrease in relative 8OHG levels compared with neurons free of NFT. Our observations indicate that increased oxidative damage is an early event in AD that decreases with disease progression and lesion formation. These findings suggest that AD is associated with compensatory changes that reduce damage from reactive oxygen.

Topics: Aged; Alzheimer Disease; Amyloid beta-Peptides; Apolipoproteins E; Brain; Disease Progression; Female; Genotype; Guanosine; Heterozygote; Humans; Male; Middle Aged; Neurofibrillary Tangles; Neurons; Oxidative Stress; Plaque, Amyloid; Tyrosine

The predictable chronological sequence of pathological events in Down syndrome (DS) provides the opportunity to rigorously investigate the relationship between oxidative stress and amyloid-beta (Abeta) deposition. In this study, we report a marked accumulation of oxidized nucleic acid, 8-hydroxyguanosine (8OHG), and oxidized protein, nitrotyrosine, in the cytoplasm of cerebral neurons in DS with the levels of nucleic acid and protein oxidation paralleling each other. Relative density measurements of neuronal 8OHG immunoreactivity showed that there was a significant increase (p < 0.02) in DS (n = 22, ages 0.3-65 yr) compared with age-matched controls (n = 10, ages 0.3-64 yr). As a function of age, 8OHG immunoreactivity increased significantly in the teens and twenties (p < 0.04), while Abeta burden only increased after age 30 (p < 0.0001). In 9 cases of DS bearing Abeta deposition, the extent of deposits of Abeta ending at amino acid 42 (Abeta42) was actually associated with a decrease in relative 8OHG (r = -0.79, p < 0.015) while Abeta40 was not. These findings suggest that in brains of patients with DS, increased levels of oxidative damage occur prior to the onset of Abeta deposition.

Topics: Adolescent; Adult; Aged; Amyloid beta-Peptides; Cerebral Cortex; Child; Child, Preschool; Down Syndrome; Guanosine; Humans; Middle Aged; Neurons; Oxidative Stress; Tyrosine