PMID- 8902270
OWN - NLM
STAT- MEDLINE
DCOM- 19970220
LR  - 20061115
IS  - 0893-228X (Print)
IS  - 0893-228X (Linking)
VI  - 9
IP  - 7
DP  - 1996 Oct-Nov
TI  - Measurement of oxidative damage at pyrimidine bases in gamma-irradiated DNA.
PG  - 1145-51
AB  - Oxidized nucleobases represent one of the main classes of damage induced in DNA 
      by ionizing radiation. Emphasis was placed in this work on the measurement of 
      four oxidized pyrimidine bases, including 5-(hydroxymethyl)uracil (5-HMUra), 
      5-formyluracil (5-ForUra), 5-hydroxycytosine (5-OHCyt), and 5-hydroxyuracil 
      (5-OHUra), in isolated DNA upon exposure to gamma radiation in aerated aqueous 
      solution. For this purpose, both high performance liquid chromatography 
      associated with electrochemical detection (HPLC-EC) and gas chromatography 
      coupled to mass spectrometry (GC-MS) were used. Conditions of hydrolysis of the 
      N-glycosidic bond were carefully checked in order to achieve a quantitative 
      release of the lesions. We showed that 60% formic acid treatment leads to the 
      decomposition of the four lesions studied. On the other hand, hydrolysis based on 
      the use of either 88% formic acid or 70% hydrogen fluoride in pyridine (HF/Pyr) 
      allowed the quantitative release of the modified bases, with the exception of 
      5-HMUra when the latter reagent was utilized. A dose course study of the 
      radiation-induced formation of 5-HMUra and 5-ForUra in DNA by using the GC-MS 
      assay showed that the latter lesion was produced in a 2.1-fold higher yield than 
      the former one. HF/Pyr and 88% formic acid hydrolysis provided similar results 
      for 5-ForUra, indicating the reliability of both techniques for the measurement 
      of this lesion. For 5-OHUra and 5-OHCyt, the level of modification determined by 
      GC-MS analysis was higher after 88% formic acid treatment than upon HF/Pyr 
      hydrolysis. When DNA was enzymatically digested and analyzed by HPLC-EC for 
      5-OHdCyd and 5-OHdUrd, the results were very close to those obtained by GC-MS 
      following HF/Pyr treatment. It was concluded that additional amounts of both 
      5-OHUra and 5-OHCyt are produced during the 88% formic acid treatment from 
      radiation-induced 5,6-saturated pyrimidine precursors. It is likely that cytosine 
      and uracil diols are involved in this reaction. The radiochemical yields of 
      formation (in mumol.J-1) for the products studied are in the following decreasing 
      order: 5-ForUra (0.0083) > 5-OHCyt (0.0046) > 5-HMUra (0.0039) > 5-OHUra 
      (0.0035).
FAU - Douki, T
AU  - Douki T
AD  - CEA/Departement de Recherche Fondamentale sur la Matiere Condensee, France.
FAU - Delatour, T
AU  - Delatour T
FAU - Paganon, F
AU  - Paganon F
FAU - Cadet, J
AU  - Cadet J
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Chem Res Toxicol
JT  - Chemical research in toxicology
JID - 8807448
RN  - 0 (Pyrimidines)
SB  - IM
MH  - Animals
MH  - Cattle
MH  - DNA Damage/*radiation effects
MH  - Gamma Rays/*adverse effects
MH  - Gas Chromatography-Mass Spectrometry
MH  - Oxidation-Reduction
MH  - Pyrimidines/*metabolism/*radiation effects
MH  - Thymus Gland/metabolism
EDAT- 1996/10/01 00:00
MHDA- 1996/10/01 00:01
CRDT- 1996/10/01 00:00
PHST- 1996/10/01 00:00 [pubmed]
PHST- 1996/10/01 00:01 [medline]
PHST- 1996/10/01 00:00 [entrez]
AID - tx960095b [pii]
AID - 10.1021/tx960095b [doi]
PST - ppublish
SO  - Chem Res Toxicol. 1996 Oct-Nov;9(7):1145-51. doi: 10.1021/tx960095b.