Rendering of the source text

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<!--
This CellML file was generated on 8/18/2011 at 1:28:59 at PM using:

COR (0.9.31.1409)
Copyright 2002-2011 Dr Alan Garny
http://cor.physiol.ox.ac.uk/ - cor@physiol.ox.ac.uk

CellML 1.0 was used to generate this model
http://www.cellml.org/
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        <title>Model Status</title>
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         Made in COR. Model a runs in OpenCell to recreate results from  published paper but model b does not reproduce results. CellML files are based on equations 1-3 (a) and 1 and 4-8 (b).
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      <sect1 id="sec_structure">
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ABSTRACT: Cytosolic calcium plays a crucial role as a second messenger in cellular signalling. Various cell types, including hepatocytes, display Ca(2+)oscillations when stimulated by an extracellular signal. However, the biological relevance of this temporal organization remains unclear. In this paper, we investigate theoretically the effect of Ca(2+)oscillations on a particular example of cell regulation: the phosphorylation-dephosphorylation cycle controlling the activation of glycogen phosphorylase in hepatocytes. By modelling periodic sinusoidal variations in the intracellular Ca(2+)concentration, we show that Ca(2+)oscillations reduce the threshold for the activation of the enzyme. Furthermore, as the activation of a given enzyme depends on the kinetics of its phosphorylation-dephosphorylation cycle, specificity can be encoded by the oscillation frequency. Finally, using a model for signal-induced Ca(2+)oscillations based on Ca(2+)-induced Ca(2+)release, we show that realistic Ca(2+)oscillations can potentiate the response to a hormonal stimulation. These results indicate that Ca(2+)oscillations in hepatocytes could contribute to increase the efficiency and specificity of cellular signalling, as shown experimentally for gene expression in lymphocytes (Dolmetsch et al., 1998).</para>

        <para>
The complete original paper reference is cited below:
</para>
        <para>
         Activation of the Liver Glycogen Phosphorylase by Ca2+ Oscillations: a Theoretical Study, David Gall et al, 2009, <emphasis>Activation of the Liver Glycogen Phosphorylase by Ca2+ Oscillations: 
a Theoretical Study </emphasis>, 207, 445-454. <ulink url="http://www.ncbi.nlm.nih.gov/pubmed/11093832">PubMed ID: 11093832</ulink>
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          <caption>Calcium in cell</caption>
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