Document Detail

Density-dependent limitation of growth and the regulation of cell replication by changes in the triggering level of the cell cycle switch.
MedLine Citation:
PMID:  597594     Owner:  NLM     Status:  MEDLINE    
If the initiation/suppression of cell replication results from the operation of an intracellular switch, then proliferation control can be expected to occur through the modulation of its threshold setting or sensitivity. Assuming the existence of a threshold and the uptake of regulators by an equilibrium process, one can explain various types of dependency of the maximum cell density on the initial level of the regulator (e.g., serum) in the medium. Moreover it becomes theoretically possible to distinguish whether an altered threshold or equilibrium constant is responsible for modified proliferation characteristics. It is pointed out that some published data on transformed cells are more consistent with an altered threshold than the permeability change invoked. Other data suggests that transformation has produced more complex effects. The arguments presented indicate that while some cells may be more susceptible to control via changes in the relevant equilibrium constant, others may respond more markedly to threshold modulation. If control occurs through inhibition of replication, it is possible for the system to exhibit a critical "mass": if this is exceeded (in ways discussed) proliferation could continue indefinitely provided adequate nutrients are available. An oscillator concept of the cell cycle accounts for the existence of a threshold and also permits a general understanding of its modulation by multiple agents. It is concluded that at least some forms of cancer are the result of altered thresholds.
D A Gilbert
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Bio Systems     Volume:  9     ISSN:  0303-2647     ISO Abbreviation:  BioSystems     Publication Date:  1977 Dec 
Date Detail:
Created Date:  1978-03-21     Completed Date:  1978-03-21     Revised Date:  2000-12-18    
Medline Journal Info:
Nlm Unique ID:  0430773     Medline TA:  Biosystems     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  215-28     Citation Subset:  IM    
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MeSH Terms
Cell Adhesion
Cell Cycle*
Cell Division*
Cell Membrane Permeability
Cells, Cultured / cytology*
Culture Media
Models, Biological
Neoplasms / pathology
Osmolar Concentration
Surface Properties
Reg. No./Substance:
0/Culture Media; 0/Mitogens

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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