Linked Life Data

7579433

Source:http://linkedlifedata.com/resource/pubmed/id/7579433

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1995-11-27
pubmed:abstractText
A method for quantitating the proportion of cycling long-term culture-initiating cells (LTC-IC) in heterogeneous populations of human hematopoietic cells is described. This procedure involves incubating the cells of interest for 16 to 24 hours in a serum-free medium containing 100 ng/mL Steel factor (SF), 20 ng/mL interleukin-3 (IL-3), and 20 ng/mL granulocyte-colony-stimulating factor (G-CSF), with or without 20 microCi/mL of high specific activity 3H-thymidine (3H-Tdr) before plating the recovered cells in standard LTC-IC assays. The details of this procedure are based in part on the finding that the number of LTC-IC (regardless of their cycling status) remains constant for at least 24 hours under these culture conditions, as long as 3H-Tdr is not present. In addition, we have determined that a 16-hour period of exposure to the 3H-Tdr is sufficient to maximize the discrimination of cycling LTC-IC but not long enough to allow a detectable redistribution of LTC-IC between noncycling and cycling compartments. Finally, any isotope reutilization that may occur is not sufficient to affect the LTC-IC 3H-Tdr suicide values measured. Application of this methodology to normally circulating LTC-IC showed these to be a primarily quiescent population. However, within 72 hours of incubation in a serum-free medium containing SF, IL-3, and G-CSF, most had entered S-phase, although there was no net change in their numbers. This suggests that, under certain conditions in vitro, self-renewal divisions of LTC-IC can occur and, at least initially, balance any losses of these cells due to their differentiation or death. In contrast, many of the LTC-IC in freshly aspirated samples of normal marrow were found to be proliferating, although those that were initially quiescent could also be recruited into S-phase within 72 hours in vitro when incubated under the same conditions used to stimulate circulating LTC-IC. This modified 3H-Tdr suicide procedure should facilitate further investigation of the mechanisms regulating the turnover of the most primitive compartments of human hematopoietic cells and how these may be altered in disease states or exploited for a variety of therapeutic applications.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-4971
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
86
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3314-21
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Quantitation of the quiescent fraction of long-term culture-initiating cells in normal human blood and marrow and the kinetics of their growth factor-stimulated entry into S-phase in vitro.
pubmed:affiliation
Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't