Linked Life Data

10468211

Source:http://linkedlifedata.com/resource/pubmed/id/10468211

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3-4
pubmed:dateCreated
1999-11-2
pubmed:abstractText
Recently, an artifactual formation of a number of modified DNA bases has been alleged during derivatization of DNA hydrolysates to be analyzed by gas chromatography-mass spectrometry (GC-MS). These modified bases were 8-hydroxyguanine (8-OH-Gua), 5-hydroxycytosine (5-OH-Cyt), 8-hydroxyadenine (8-OH-Ade), 5-hydroxymethyluracil (5-OHMeUra), and 5-formyluracil, which represent only a small percentage of more than 20 modified DNA bases that can be analyzed by GC-MS. However, relevant papers reporting the levels of these modified bases in DNA of various sources have not been cited, and differences in experimental procedures have not been discussed. We investigated the levels of modified bases in calf thymus DNA by GC-MS using derivatization at three different temperatures. The results obtained with GC/isotope-dilution MS showed that the levels of 5-OH-Cyt, 8-OH-Ade, 5-OH-Ura, and 5-OHMeUra were not affected by increasing the derivatization temperature from 23 degrees C to 120 degrees C. The level of 8-OH-Gua was found to be higher at 120 degrees C. However, this level was much lower than those reported previously. Formamidopyrimidines were readily analyzed in contrast to some recent claims. The addition of trifluoroacetic acid (TFA) adversely affected the levels of pyrimidine-derived lesions, suggesting that TFA is not suitable for simultaneous measurement of both pyrimidine- and purine-derived lesions. The data obtained were also compared with those previously published. Our data and this comparison indicate that no artifactual formation of 5-OH-Cyt, 8-OH-Ade, and 5-OHMeUra occurred under our experimental conditions in contrast to recent claims, and no prepurification of DNA hydrolysates by a tedious procedure is necessary for accurate quantification of these compounds. The artifactual formation of 8-OH-Gua can be eliminated by derivatization at room temperature for at least 2 h, without the use of TFA. The results in this article and their comparison with published data indicate that different results may be obtained in different laboratories using different experimental conditions. The data obtained in various laboratories should be compared by discussing all relevant published data and scientific facts, including differences between experimental conditions used in different laboratories.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/5-formyluracil, http://linkedlifedata.com/resource/pubmed/chemical/5-hydroxycytosine, http://linkedlifedata.com/resource/pubmed/chemical/5-hydroxymethyluracil, http://linkedlifedata.com/resource/pubmed/chemical/8-hydroxyadenine, http://linkedlifedata.com/resource/pubmed/chemical/8-hydroxyguanine, http://linkedlifedata.com/resource/pubmed/chemical/Adenine, http://linkedlifedata.com/resource/pubmed/chemical/Cytosine, http://linkedlifedata.com/resource/pubmed/chemical/DNA, http://linkedlifedata.com/resource/pubmed/chemical/Guanine, http://linkedlifedata.com/resource/pubmed/chemical/Nucleotides, http://linkedlifedata.com/resource/pubmed/chemical/Pentoxyl, http://linkedlifedata.com/resource/pubmed/chemical/Trifluoroacetic Acid, http://linkedlifedata.com/resource/pubmed/chemical/Uracil
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0891-5849
pubmed:author
pubmed:issnType
Print
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
370-80
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
The effect of experimental conditions on the levels of oxidatively modified bases in DNA as measured by gas chromatography-mass spectrometry: how many modified bases are involved? Prepurification or not?
pubmed:affiliation
Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899-8311, USA.
pubmed:publicationType
Journal Article, Comparative Study