[Effect of lyophilization on the free-radical state of animal cells]

The process of lyophylisation carried out very carefully under strictly defined conditions does not in inself bring about the changes in the parameters of the ESR signal with g approximately equal to 2.00 observed in animal cells. The free radicals responsible for the ESR signal observed under usual experimental conditions, result from a contact of the lyophylised specimen with moisture at an optimum water content of about 10%.