Production of prostacyclin (PGI2) and thromboxane A2 (TXA2) by vessels draining and not-draining benign and malignant tumours of the breast.

The production of PGI2 (determined by bioassay) and TXB2 (determined by radioimmunoassay) was studied in the supernatant solutions obtained after incubation of vessel rings prepared from veins draining and not draining benign and malignant tumours of the breast. A significant increase (p less than 0.01) was found in the production of PGI2 by vessels draining the malignant tumours as compared to those not draining such tumours or vessels draining benign tumours. The changes in PGI2, and the tendency for TXB2 to be higher in vessels draining malignant tumours, were in the same direction so that they balanced out when the ratio PGI2/TXB2 was calculated: in consequence no significant changes in this ratio were found in malignant tumours as compared to the benign. A significant difference (p less than 0.01) was observed in the ratios of vessels draining tumours:vessels not draining tumours between malignant and benign tumours in relation to the production of PGI2. The present data demonstrate that the production of PGI2 by vessels draining malignant tumours of the breast is different to that obtained with vessels from patients with benign tumours, although the mechanism responsible for this difference is not known.

Platelet sensitivity to prostacyclin in normal subjects, and in patients with benign and malignant tumours of the breast.

Platelet sensitivity to prostacyclin (PG12) was determined in normal male and female subjects, and in patients with benign and malignant tumours of the breast. The IC50 overall mean values for PG12 on ADP-induced platelet aggregation were similar for normal men and women, being 0.97 +/- 0.05 ng ml-1 and 0.83 +/- 0.07 ng ml-1 respectively. However, there were significant differences in the IC50 values for women in the 1st (0.81 +/- 0.06 ng ml-1) vs. 2nd (1.37 +/- 0.13 ng ml-1) phase of the menstrual cycle; post-menopausal women gave similar values to normal males and to pre-menopausal women in the 1st phase of the cycle. No significant differences were found between normal subjects and patients with benign or malignant tumours of the breast when account was taken of the status of the patient in relation to the phase of the menstrual cycle and the menopause. The importance of the hormonal status in evaluating changes in platelet sensitivity in patients with breast cancer is strongly emphasised.

Production of prostacyclin, 6-keto-PGF1 alpha and thromboxane B2 by incubated samples of umbilical vessels: a comparison of methods for expressing the results on dry weight, wet weight, protein or DNA bases.

The production of PGI2 (determined by bioassay), and of 6-keto-PGF1 alpha and TXB2 (determined by radioimmunoassay) by samples of human umbilical vessels have been measured. The results have been calculated on four bases: dry weight, wet weight, protein and DNA. There was a higher production of PGI2 and 6-keto-PGF1 alpha by umbilical veins than by umbilical arteries; no significant difference in TXB2 production was observed between umbilical veins and arteries. The ratio of 6-keto-PGF1 alpha: TXB2 production was about 100 for the samples of veins and about 40 for the samples of arteries. The best methods of expressing the results were on the bases of protein and DNA, the latter basis being marginally the best. The least satisfactory method for expressing the results was that based on dry weight. The physiological and practical implications of the results are discussed.