RESUMO
With techniques of biochemical isolation and pruification, a semi-purified preparation of new born calf liver (BLS) with the peculiarity of low molecular weight has been found to have tumor surppressor activity inhibiting selectively the growth of murine myeloid leukemic cell (L801). But its effect is less marked against normal bone marrow granulocyte / macrophage progenitors in in vitro liquid or agar culture. Mice after inoculation of L801 cells died within 15 days due to development of leukemia. After consecutive injections of BLS, 25% - 53.8% of treated mice survived. Furthermore, it has been found that the survival rate was raised from 50% to 66% when Cyclophosphamide was first injected in the dose of 300?g / kg body weight once, followed by the consecutive injections of BLS. NO pathological changes have been observed in the mice which survived longer than 100 days after inoculation of L801 leukemic cells.