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dc.contributor.authorOckey, Charles H
dc.date.accessioned2011-07-04T11:04:58Z
dc.date.available2011-07-04T11:04:58Z
dc.date.issued1980
dc.identifier.citationDifferences between "spontaneous" and induced sister-chromatid exchanges with fixation time and their chromosome localization. 1980, 26 (2-4):223-35 Cytogenet Cell Geneten
dc.identifier.issn0301-0171
dc.identifier.pmid6967000
dc.identifier.urihttp://hdl.handle.net/10541/135234
dc.description.abstractMean "spontaneous" SCE values have been investigated in synchronized CHO and S3/4 fibroblasts and in phytostimulated human peripheral lymphocytes. Significant increases were found at progressive fixation times following BrdU introduction in all cultures. Similar increases were observed with fixation times in SCEs induced by pulse treatment with methyl methane sulphonate (MMS) at various stages in the S period in CHO cells. In the fibroblast cultures these increases ranged from 20 to 80% with an 8-h interval between fixations. The percentage increase depended on the real proliferation occurring during this fixation interval. In the lymphocyte cultures, fixation intervals raning from 22 to 54 h yielded increases of 40 to 80%. It is proposed that when SCE yields are compared in the SCE test for potentially damaging agents, the stages in cell proliferation expressed as frequencies of first, second, and third mitoses after BrdU incorporation should be taken into account. The distribution of "spontaneous" and MMS-induced SCE's have been examined in marker chromosomes of the CHO cells. Although "spontaneous" SCE's are nonrandomly distributed, they do not appear to show a high incidence over any specific type of banded region. MMS-induced SCEs, on the other hand, are preferentially located over those chromosome sites in replication at the time of pulse treatment.
dc.language.isoenen
dc.subject.meshAnimals
dc.subject.meshBromodeoxyuridine
dc.subject.meshCell Cycle
dc.subject.meshCell Line
dc.subject.meshCells, Cultured
dc.subject.meshChromosome Banding
dc.subject.meshCricetinae
dc.subject.meshCricetulus
dc.subject.meshCrossing Over, Genetic
dc.subject.meshFemale
dc.subject.meshFibroblasts
dc.subject.meshHumans
dc.subject.meshMale
dc.subject.meshMethyl Methanesulfonate
dc.subject.meshShrews
dc.subject.meshSister Chromatid Exchange
dc.subject.meshT-Lymphocytes
dc.subject.meshTime Factors
dc.titleDifferences between "spontaneous" and induced sister-chromatid exchanges with fixation time and their chromosome localization.en
dc.typeArticleen
dc.contributor.departmentPaterson Laboratories Christie Hospital and Holt Radium Institute, Manchester M20 9BX, U.K.en
dc.identifier.journalCytogenetics and Cell Geneticsen
html.description.abstractMean "spontaneous" SCE values have been investigated in synchronized CHO and S3/4 fibroblasts and in phytostimulated human peripheral lymphocytes. Significant increases were found at progressive fixation times following BrdU introduction in all cultures. Similar increases were observed with fixation times in SCEs induced by pulse treatment with methyl methane sulphonate (MMS) at various stages in the S period in CHO cells. In the fibroblast cultures these increases ranged from 20 to 80% with an 8-h interval between fixations. The percentage increase depended on the real proliferation occurring during this fixation interval. In the lymphocyte cultures, fixation intervals raning from 22 to 54 h yielded increases of 40 to 80%. It is proposed that when SCE yields are compared in the SCE test for potentially damaging agents, the stages in cell proliferation expressed as frequencies of first, second, and third mitoses after BrdU incorporation should be taken into account. The distribution of "spontaneous" and MMS-induced SCE's have been examined in marker chromosomes of the CHO cells. Although "spontaneous" SCE's are nonrandomly distributed, they do not appear to show a high incidence over any specific type of banded region. MMS-induced SCEs, on the other hand, are preferentially located over those chromosome sites in replication at the time of pulse treatment.


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