Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
3
|
| pubmed:dateCreated |
1989-5-1
|
| pubmed:abstractText |
The onset of quiescence, changes in X-ray sensitivity, and changes in capacity for potentially lethal damage (PLD) repair of unfed plateau-phase 9L44 cell cultures have been systematically investigated. The quiescent plateau phase in 9L cells was the result of nutrient deprivation and was not a cell contact effect. Eighty-five to 90% of the plateau-phase cells had a G1 DNA content and a growth fraction less than or equal to 0.15. The cell kinetic shifts in the population were temporally correlated with a developing radioresistance, which was characterized by a larger shoulder in the survival curve of the quiescent cells (Dq = 5.71 Gy) versus exponentially growing cells (Dq = 4.48 Gy). When the quiescent plateau-phase cells were refed, an increase in radiosensitivity resulted which approached that of exponentially growing 9L cells. Delayed plating experiments after irradiation of exponentially growing cells, quiescent plateau-phase cells, and synchronized early to mid-G1-phase cells indicated that while significant PLD repair was evident in all three populations, the quiescent 9L cells had a higher PLD repair capacity. Although data for immediate plating indicated that 9L cells may enter quiescence in the relatively radioresistant mid-G1 phase, the enhanced PLD repair capacity of quiescent cells cannot be explained by redistribution into G1 phase. When the unfed quiescent plateau-phase 9L cells were stimulated to reenter the cell cycle by replating into fresh medium, the first G1 was extended by 6 h compared with the G1 of exponentially growing or refed plateau-phase 9L cells.(ABSTRACT TRUNCATED AT 250 WORDS)
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:status |
MEDLINE
|
| pubmed:month |
Mar
|
| pubmed:issn |
0033-7587
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
117
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
433-47
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading | |
| pubmed:year |
1989
|
| pubmed:articleTitle |
Quiescence in 9L cells and correlation with radiosensitivity and PLD repair.
|
| pubmed:affiliation |
Biology and Medicine Division, Lawrence Berkeley Laboratory, University of California, Berkeley 94720.
|
| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, Non-P.H.S.
|