Background: Oxidatively generated damage to DNA has been implicated in the pathogenesis of a wide variety of diseases. The noninvasive assessment of such damage, i.e., in urine, and application to large-scale human studies are vital to understanding this role and devising intervention strategies. Methods: We have reviewed the literature to establish the status quo with regard to the methods and meaning of measuring DNA oxidation products in urine. Results: Most of the literature focus upon 8-oxo-7,8-dihydro-2 ¶-deoxyguanosine (8-oxodG), and whereas a large number of these reports concern clinical conditions, there remains (a) lack of consensus between methods, (b) possible contribution from diet and/or cell death, (c) no definitive DNA repair source of urinary 2 ¶-deoxyribonucleoside lesions, and (d) no reference ranges for healthy or diseased individuals. Conclusions: The origin of 8-oxodG is not identified; however, recent cell culture studies suggest that the

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Iron deficiency is a common health problem. The most severe consequence of this disorder is iron deficiency anemia (IDA), which is considered the most common nutritional deficiency worldwide. Newborn piglets are an ideal model to explore the multifaceted etiology of IDA in mammals, as IDA is the most prevalent deficiency disorder throughout the early postnatal period in this species and frequently develops into a critical illness. Here, we report the very low expression of duodenal iron transporters in pigs during the first days of life. We postulate that this low expression level is why the iron demands of the piglet body are not met by iron absorption during this period. Interestingly, we found that a low level of duodenal divalent metal transporter 1 and ferroportin, two iron transporters located on the apical and basolateral membrane of duodenal absorptive enterocytes, respectively, correlates with abnormally high expression of hepcidin, despite the poor hepatic and overall iron status of these animals. Parenteral iron supplementation by a unique intramuscular administration of large amounts of iron dextran is current practice for the treatment of IDA in piglets. However, the potential toxicity of such supplemental iron implies the necessity for caution when applying this treatment. Here we demonstrate that a modified strategy for iron supplementation of newborn piglets with iron dextran improves the piglets' hematological status, attenuates the induction of hepcidin expression, and minimizes the toxicity of the administered iron. (Am J Pathol

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Aims: Urinary 8-oxo-7,8-dihydro-2¢-deoxyguanosine (8-oxodG) is a widely used biomarker of oxidative stress. However, variability between chromatographic and ELISA methods hampers interpretation of data, and this variability may increase should urine composition differ between individuals, leading to assay interference. Furthermore, optimal urine sampling conditions are not well defined. We performed inter-laboratory comparisons of 8-oxodG measurement between mass spectrometric-, electrochemical-and ELISA-based methods, using common within-technique calibrants to analyze 8-oxodG-spiked phosphate-buffered saline and urine samples. We also investigated human subject-and sample collection-related variables, as potential sources of variability. Results: Chromatographic assays showed high agreement across urines from different subjects, whereas ELISAs Kronos Science, Phoenix, Arizona. ANTIOXIDANTS & REDOX SIGNALINGVolume 18, Number 18, 2013 ª Mary Ann Liebert, Inc. DOI: 10.1089/ars.2012.4714 2377showed far more inter-laboratory variation and generally overestimated levels, compared to the chromatographic assays. Excretion rates in timed 'spot' samples showed strong correlations with 24 h excretion (the 'gold' standard) of urinary 8-oxodG (r p 0.67-0.90), although the associations were weaker for 8-oxodG adjusted for creatinine or specific gravity (SG). The within-individual excretion of 8-oxodG varied only moderately between days (CV 17% for 24 h excretion and 20% for first void, creatinine-corrected samples). Innovation: This is the first comprehensive study of both human and methodological factors influencing 8-oxodG measurement, providing key information for future studies with this important biomarker. Conclusion: ELISA variability is greater than chromatographic assay variability, and cannot determine absolute levels of 8-oxodG. Use of standardized calibrants greatly improves intra-technique agreement and, for the chromatographic assays, importantly allows integration of results for pooled analyses. If 24 h samples are not feasible, creatinine-or SG-adjusted first morning samples are recommended.

Free rudi&induscd damegc to DNA in vivo is implicated to play II role in cwcinogcncris. Ewidcncc exists thal DNA dnmnpc by cndoynous free radiuls occurs in vivo, und thcrc is a rtcadpstatc lwcl of free radic&moditIcd hascs in ccllullrr DNA. WC hove invaligPtcd cndogcnous lcvcls of typical free rztdic&induscd DNA bits modifications in chromriz of various human cancerous tissues and their canswfrec rurrounding~issucr.Five different lypcr of sur@cally rcmovcd tirsucr were UK& nttmcly eolon, stomach. ovary, brain and lung tissues. In chromntin samples ivolatcd fram thcsc tissues. iivc pyrimidinedcrivcd and six purinc-dcrivcd modillcd DNA busts wcrc idcntincd and quantitatcd by ~schromatographyltnass spsctromctry with rslcctcd.ion monitoring, Thcsc wcrc 5.hydrox~S~mcthylhydantoin, 5.hydroxyhydantoin, 5~(hydroxymcthyl)urcil, S.hydroxycy. torinc, 5,6.dihydroxycyt6dac. 4.6~diamino.S-formnmidopyrimidinc.t.hydr.rxyudcninc, xnnthinc, I.hydronyodcninc, 2,6diaminc&hydron~5. furmnmidopyrimidinc, and 8*hydroxy8uaninc. That compounds arc known to bc formed typically by hydroxyl rsdisal attach on DNA bw. In all ems, clcvatcd umounts over control lcvcls of modifIcd DNA bares WCFC found in cancerous tirrucr. The umounta of modified beset dcpndcd nn the tiwc type, Lung tissues rcmovcd from mokcrs hlrd the highest incrcnrlr of modified bases ubovc the conrrol Icvcls, and the hifisst overall umounts, Colon cunscr tissue samples hurl the lowcrt lncrcuscs of mdiClcd bttscs over the control Icwls. The results clearly indicate hi&r rtcady&!tc lcvclr of moditlcd DNA basss in cancerous tirsucr thaw in their cunccr.frcc surrounding tirruss~ Some of thcsc l-ions arc known lo tx promutagenic. although others have not been invcrriylltcd for their mutpycnicity, Identified DNA lctions mny play B cwsativc role in atrcinoycncr!r.

A broad scientific community is involved in investigations aimed at delineating the mechanisms of formation and cellular processing of oxidatively generated damage to nucleic acids. Perhaps as a consequence of this breadth of research expertise, there are nomenclature problems for several of the oxidized bases including 8-oxo-7,8-dihydroguanine (8-oxoGua), a ubiquitous marker of almost every type of oxidative stress in cells. Efforts to standardize the nomenclature and abbreviations of the main DNA degradation products that arise from oxidative pathways are reported. Information is also provided on the main oxidative radicals, non-radical oxygen species, one-electron agents and enzymes involved in DNA degradation pathways as well in their targets and reactivity. A brief classification of oxidatively generated damage to DNA that may involve single modifications, tandem base modifications, intrastrand and interstrand cross-links together with DNA-protein cross-links and base adducts arising from the addition of lipid peroxides breakdown products is also included.

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