Granule Coupled with k Inactivating (or Non-Inactivating) CaVs.
Surprisingly and in contrast with the case with inactivating CaVs, as the number of non-inactivating CaVs increases, the relative rise in exocytosis rate is much higher at larger distances from the CaVs, as shown in Figure 3(j) reporting the relative rate [mathematical expression not reproducible].
To investigate the relationship between exocytosis and [Ca.sup.2+] loading, we consider a set of scenarios where the granule is coupled with different number of non-inactivating or inactivating CaVs, placed very close (10 nm) or far (100 nm) from the granule.
We develop Markov chain models describing the dynamics of a single granule coupled with one or more inactivating (or non-inactivating) [Ca.sup.2+] channels and use phase-type distribution results  for estimating the expected exocytosis rate.
Further and in agreement with experiments , the simulations presented here show that the increase of the number of CaVs coupled with the granule determines a much higher rise of the exocytosis rate, which in the case of inactivating CaVs is more pronounced when the granule is close to CaVs ([approximately equal to] 10 nm), whereas for non-inactivating CaVs the highest relative increase in rate is obtained when the CaVs are far from CaVs ([approximately equal to] 50 nm).
Surprisingly, for the case of inactivating CaVs, our analysis shows a change of the linear relation between [p.sub.Y] and QCa due to near-complete inactivation of CaVs.
New methods of inactivating pathogens would be especially advantageous for reducing bacterial contamination of platelets, which are particularly vulnerable because they must be stored at room temperature, says Roger Dodd, president of the American Association of Blood Banks in Bethesda, Md.
of Concord, Calif., has already gotten approval in Europe to market a system for inactivating pathogens in platelets and plasma.