| Abstrakt: |
To determine the route by which the virus spreads from the portal of entry to the medulla and cord, previous investigators have examined different regions of the central nervous system at varying intervals of time during the preparalytic period for the presence of virus. The results of these and related studies have established that poliomyelitis virus spreads axonally,1probably as an intraneural infection.The work we wish to report represents an extension of these earlier studies in which the presence or absence of virus was merely determined and the amount present was not actually measured. Our investigations deal with the concentrations which are reached by the virus during the preparalytic period. They were prompted in part by certain observations on the kinetics of bacteriophagy which indicate that the lytic agent is at first produced in the absence of recognizable bacterial lysis and that actual lysis is not initiated until a certain critical concentration of the agent has been reached.2The mechanism of this prelytic formation of bacteriophage is not yet known and need not concern us here. In the studies here reported it was our purpose merely to determine the concentration of poliomyelitis virus which is reached in different regions of the central nervous system and to relate this, if possible, to the extent of neuronal damage sustained in the particular regions, the guiding hypothesis being that the production of virus and of nerve cell damage do not necessarily parallel each other and that certain neurons, although supplying a pabulum for the production of virus may, nevertheless, be relatively resistant to its action.Part of our observations was made on intracranially inoculated animals; part on intranasally inoculated animals. |
