Induction and disappearance of DNA strand breaks and/or alkalilabile sites in human lymphocytes exposed to N-ethyl-N-nitrosourea

Michael E.T.I. Boerrigter, Erik Mullaart, Frits Berends, Jan Vijg

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13 Scopus citations


We investigated the induction and disappearance of DNA lesions that are detected as single-strand breaks (SSBs) with the alkaline filter elution technique, in human peripheral blood lymphocytes (PBLs) following exposure to N-ethyl-Nnitrosourea (ENU). In PBLs of the 15 individuals studied, 35 ± 16% (mean ± SD) of the SSBs present at the end of a 20 min treatment disappeared within 1 h; up to 24 h posttreatment no further disappearance was observed. Inter individual differences in SSB disappearance were considerable; in two cases, almost no SSBs disappeared over the 1 h period. In PBLs of the same 15 individuals 85 ± 3% (mean ± SD) of the SSBs induced by 4 Gy of γ-rays were found to disappear within 1 h, which indicated no interindividual differences. Multiple blood sampling at 1 month intervals indicated that interindividual differences in ENU-induced SSB repair are constant and do not vary with time. The low rate of SSB disappearance appeared to correlate with low cell survival after ENU exposure, measured as a reduction in phytohemagglutinin-stimulated incorporation of [3H]- thymidine. The cytosine analog 1-β-D-arabinofuranosylcytosine completely inhibited SSB disappearance, indicating that the removal of the repairable ENU-induced SSBs involves excision repair events.

Original languageEnglish (US)
Pages (from-to)77-82
Number of pages6
Issue number1
StatePublished - Jan 1991
Externally publishedYes

ASJC Scopus subject areas

  • Cancer Research


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