The effects of Corynebacterium parvum on the mouse primary Lewis lung carcinoma and its metastases were studied. C. parvum was given at the same time as subcutaneous inoculation of tumour or in combination with surgical excision of the primary after 10 days' growth. When intravenous C. parvum was given at the same time as tumour there was a reduction in the primary tumour growth rate. There was a similar reduction in growth if the drug was given intravenously 7 days after tumour inoculation. Intraperitoneal and subcutaneous administration of C. parvum had no effect on the primary tumour. The number of pulmonary metastases were significantly reduced after intravenous or intraperitoneal C. parvum given at the same time as tumour. When C. parvum and surgery were combined and C. parvum was given not more than 2 days before operation there was only a slight reduction in metastases, but when the injection was given intravenously or intraperitoneally 3-4 days before operation the number of metastases was significantly reduced. Subcutaneous administration of C. parvum had little effect on metastases. There was no difference in the number of metastases in C. parvum-treated mice were killed after 21 or 28 days. C. parvum given on the same day as surgery was more effective if tumour excision was performed before day 10 when the metastases were less well established. It was concluded that in well-defined conditions C. parvum is effective against metastases of the Lewis lung carcinoma.

In mice, i.v. C. parvum induces intravascular coagulation. This is a prolonged reaction lasting up to 7 days. It results in thrombosis in hepatic vessels with consequent hepatic necrosis, and thrombosis in pulmonary and splenic vessels. This may be important in the assessment of the tumour-inhibitory activity of C. parvum. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4

No abstract

Summary.-Leukaemic cells from rats with a lymphoid (HRL) or myeloid (SAL) leukaemia were labelled with 125IUDR and injected i.v. into either normal or leukaemic syngeneic recipients. The fate of the injected cells was studied in terms of the radioactivity in various tissues at various times up to 24 h later.In normal animals the leukaemia cells were destroyed rapidly in the reticuloendothelial (RE) system; immediately after injection most recoverable activity was in the lung, with smaller amounts in the blood, spleen and liver but by 24 h only 20-30% of the injected activity could be recovered.In leukaemic recipients with high numbers of blasts in the blood the amount of activity recoverable from the lungs and bone-marrow was markedly reduced, while that in the blood was doubled. Nonetheless, the overall rate at which radioactivity was eliminated was not significantly different from that found in normal rats, in spite of the fact that the RE system was extensively infiltrated by leukaemia cells.

No abstract