such factors other than glucose , glutamine , or salts ( e.g . amino acids , purines , pyrimidines , vitamins , protein , or nh ( 4 ) ( + ) ) as may be needed by hela cells for the propagation of poliomyelitis virus , need not be present in the medium and can not be easily washed out of the cell .
C0017797
glutamine
C0002520
amino acids