Linked Life Data

2805151

Source:http://linkedlifedata.com/resource/pubmed/id/2805151

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1989-12-21
pubmed:abstractText
The rate of DNA synthesis in normal tissues exhibits circadian rhythmicity. However, there have been conflicting reports of the effects of tumor burden on the circadian rhythm of DNA synthesis in non-cancer tissues. We have developed a mouse colon cancer (MC-26) that exhibits different growth under different photoperiods. The purpose of this study was to analyze DNA synthetic activity in tissues removed from tumor-bearing and tumor-free mice maintained under two different photoperiods. Two groups each of approximately 80 male Balb/c mice were acclimated to one of two light-dark cycles, 12L:12D or 6L:18D. Half of each group were injected with 5.0 x 10(4) MC-26 cells. Twenty-two days later, all mice were killed in subgroups at 4-6 hr intervals over one 24-hr period. Colons and tumors were removed for measurement of DNA synthesis. Results were analyzed by means of one-way analysis of variance (ANOVA) in order to determine whether DNA synthesis varied significantly within groups over the 24-hr period. The DNA synthetic activity, as measured by uptake of tritiated thymidine, exhibited significant temporal variation in the colons of control (tumor-free) mice under both the 12L:12D and 6L:18D photoperiods. The colons of tumor-bearing mice failed to exhibit a fluctuation under a 12L:12D photoperiod but did show a significant 24-hr rhythm under the 6L:18D photoperiod. The subcutaneously growing cancers did not exhibit a circadian variation in DNA synthetic activity under either photoperiod. Both photoperiod and the presence of cancer appear to affect the DNA synthetic activity observed in mice bearing the MC-26 colon cancer.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0742-0528
pubmed:author
pubmed:issnType
Print
pubmed:volume
6
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
237-43
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
DNA synthetic activity in tumor-bearing mice.
pubmed:affiliation
Department of Surgery, University of Texas Medical Branch, Galveston 77550.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't