DNA/RNA Oxidative Damage (High Sensitivity) ELISA Kit

Guanosine hydroxylation was used as a marker for assessing photooxidation of DNA and RNA sensitized by monofunctional and bifunctional furocoumarins. DNA or RNA, treated with sensitizer and UVA light, was enzymatically hydrolyzed, dephosphorylated and then analyzed by reversed-phase HPLC with electrochemical detection. Hydroxylated guanosine, i.e. 8-hydroxy-2'-deoxyguanosine (8-OHdG) or 8-hydroxyguanosine (8-OHG), was quantitated. 3-Carbethoxypsoralen (3-CP) was found to be an efficient photosensitizer for oxidation of guanosine in DNA, resulting in conversion of up to 0.4% of guanosine residues to 8-OHdG. In contrast, dramatically lower levels of guanosine hydroxylation were observed in 3-CP-photosensitized RNA. Psoralen was found to be a more efficient photosensitizer than angelicin in both DNA and RNA. Additional studies of oxidation of 3-CP-photosensitized DNA indicated that double-stranded DNA is 10 times more susceptible to photooxidation than single-stranded DNA, implicating 3-CP binding to DNA as an important mechanistic step in photooxidation of guanosine. The effects of D2O and degassing with argon on photooxidation of guanosine in DNA sensitized by 3-CP were inconsistent with a mechanism involving O-2. In addition, chelation of adventitious metal ions present in preparations of DNA photosensitized by 3-CP had no effect on hydroxylation of guanosine.

The aim of the study is to measure serum concentrations of markers of nucleic acids and proteins oxidative damage in humans to study the dynamics and clinical determinants of oxidative stress caused by acute methanol poisoning. Acute blood serum samples for this study were collected from 28 patients with methanol poisoning and the follow-up samples from 36 survivors of poisoning were collected 2years after discharge. Serum concentrations of 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), 5-(hydroxymethyl)uracil (5-OHMU), ortho-tyrosine (o-Tyr), nitrotyrosine(NO-Tyr), and chlorotyrosine (Cl-Tyr) were measured by liquid chromatography-electrospray ionisation-tandem mass spectrometry. Acute concentrations of 8-OHdG and o-Tyr were significantly higher than the follow-up concentrations (94.46.2 versus 78.0 +/- 10.0pgcm(-3); p=0.009 and 163.0 +/- 11.0 versus 124.0 +/- 17.0pgcm(-3); p<0.001, correspondingly). Survivors of methanol poisoning had higher acute 8-OHdG and 8-OHG concentrations than those who died (97.3 +/- 7.4 versus 50.0 +/- 23.0pgcm(-3); p<0.001 and 97.9 +/- 7.2 versus 83.7 +/- 6.7pgcm(-3); p=0.047). Acute concentrations of 8-OHdG, 8-OHG, 5-OHMU, and o-Tyr were higher in the patients who survived without health sequelae than in those who survived with visual and CNS sequelae (all p<0.05). Acute concentrations of markers of proteins and nucleic acids damage correlated with laboratory parameters of acidemia (anion gap) and serum ethanol concentration on admission (both p<0.05). Acute elevation of the concentration of markers of nucleic acids and proteins oxidative damage in the patients with methanol poisoning suggest that mild-to-moderate oxidative stress may play an important role in the non-specific mechanisms of brain protection against direct neurotoxic effects of formic acid. [GRAPHICS] .