The level of peripheral blood platelets was determined after i.v. injection of Corynebacterium parvum in normal C57BL mice and in those bearing the Lewis lung carcinoma. Twenty minutes after injection of a formalin-killed active strain (CN6134, (CN6134, which inhibited tumour metastases) or a killed inactive strain (CN 5888, which did not inhibit metastases) the number of circulating blood platelets was reduced by 50%. The level of platelets returned to control values by 8 h after the active, and by approximately 3 days after the inactive strain. The active strain alone caused a second and prolonged fall in platelet numbers, from approximately 16 h to 21 days after injection. Heparin given 3 X weekly to these mice restored the platelet count to normal values by 10 days after injection of active-strain C. parvum. The level of platelets in tumour-bearing mice was essentially similar to that in normal mice. Possible causes of the thrombocytopenia and the significance of platelets in metastasis are discussed.

Forty-six separate renal tumours developed in 36/80 Wistar male rats given a single i.v. dose of streptozotocin (25 mg/kg body wt) to induce diabetes mellitus. Fourteen of the tumours were epithelial in type, 8 were wholly mesenchymal and 24 were largely mesenchymal but also contained epithelial elements. The purely epithelial tumours correspond to the renal adenomas and adenocarcinomas seen in man. The mesenchymal tumours were composed either of undifferentiated spindle cells or of a mixutre of poorly differentiated mesenchyme and epithelial glands. Microscopically, the mixed tumours resembled the nephroblastomas seen in man; both elements appeared to be malignant, but in the absence of metastases this remains unproven. The management of the diabetic state did not influence the incidence of tumours, but insulin appeared to enhance tumour growth. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5

A number of recent studies have shown an association between breast-cancer risk and height, weight and dietary habits, especially fat consumption. In the present study, height and weight were determined for 179 consecutive, unselected, breast-cancer patients and age-matched controls selected from a computerized population register. Height and weight for these two groups were compared, including two different indices for overweight (Quetelet's index and Broca's index). Comparisons were repeated after subdivision into pre- and postmenopausal women. In all calculations, the mean values of patients and controls were very similar and without significant difference. It therefore seems improbable that increased height and weight or obesity constitute risk factors for breast cancer. Earlier studies may have shown differences as the result of selection mechanisms not present in this study.

A simple rapid micro-agglutination test for detecting sensitized lymphocytes from human peripheral blood is described: the poly-L-lysine (PLL) 3400 agglutination test of lymphocytes (PAL test). The incubation of lymphocytes from 30 cancer patients, 30 patients with non-malignant disease and 40 healthy controls with PLL (mol. wt 3400) is evaluated. The test was positive in 83 percent of malignant and 20 percent of non-malignant cases. All healthy controls were negative. Other peptides tested showed no significant difference in reaction between malignant and non-malignant diseases. The mechanism of detection of sensitized lymphocytes from patients with malignant disease through agglutination induced by PLL 3400 is discussed. Images Fig. 1 Fig. 2

A nationwide study of nasopharyngeal cancer in Israel, during a 9-year period (1960-68) demonstrated a mean annual incidence rate of 1.0 per 100,000 in males and 0.4 per 100,000 in females. Significantly higher incidence was observed in residents born in North Africa (3.0 in males and 1. 1 in females). Survival was relatively better in females among patients with lymphoepithelioma and in those without neurological complications. The results may support the presence of environmental factors in aetiology, though genetic predisposition cannot be ruled out.

The polarization of fluorescence from diphenyl hexatriene embedded in the membranes of intact peripheral-blood mononuclear cells has been measured and used to assess the "microviscosity" or fluidity of the membrane. Cell preparations were examined from patients with various types of leukaemia and related conditions in which circulating primitive cells may occur. Significantly lower fluorescence polarization values were obtained in all samples from patients with chronic lymphocytic leukaemia, but normal results were obtained in cases of chronic granulocytic leukaemia, myelosclerosis, solid lymphomas and in acute leukaemias in remission. In relapsed acute leukaemia, fluorescence polarization indicated reduced "microviscosity" of the cell membrane when large numbers (greater than 10(9)/1) of primitive cells were present; normal "microviscosity" was indicated when less than 10(9)/1 primitive cells were present. However, exceptions occurred in both cases, and the technique failed to give warning of imminent relapse in one case. Our findings suggest that a reduction in "microviscosity" as indicated by this technique is not a general property of the blood leucocytes in all types of leukaemia, and that the technique cannot, at present, be regarded as an alternative method for detecting circulating primitive cells.