We studied the effect of emotional stress (mental arithmetic for 10 min) in 10 postinfarction patients and in 10 age-matched apparently healthy subjects as controls. Blood samples for platelet function studies and for the determination of epinephrine levels in serum were taken in basal conditions, at the end of mental stress and after 30 min of recovery. Patients were studied twice, in washout of medications and after oral administration of dipyridamole, 200 mg twice a day for 6 consecutive days. Mental stress induced in patients significant increments in different hemodynamic parameters (heart rate, systolic blood pressure and diastolic blood pressure) and in serum epinephrine levels. Concomitantly, the test produced a significant increase in platelet aggregation (induced by 3 µM ADP or 1 µg/ml collagen), the formation of circulating platelet aggregates and an increase in plasma thromboxane B₂ levels. Hemodynamic parameters and platelet function tests returned to baseline values after 30 min. Similar activation of hemodynamic parameters, similar increase in epinephrine levels and lower increase in platelet function by emotional stress were observed in control subjects. Treatment of patients with dipyridamole had no effect on stress-induced increase in hemodynamic parameters and epinephrine levels, but decreased stress-related platelet activation. These data can contribute to a better understanding of the complex relationships between psychosocial factors, the hemostatic system and vascular disease.

Among all the patients treated by the Italian Cooperative Group for TTP, we retrospectively reviewed the results obtained using vincristine (VCR) in 8 TTP patients (4 men and 4 women, average age: 39.25 years, range: 23–48) who did not respond to combined apheretic and pharmacologic treatment. All patients, after failing to respond to treatment, were started on VCR at the dose of 2 mg, i.v., once a week. Despite this treatment, 4 patients (50%) died 1, 7, 12 and 25 days after the first VCR dose, respectively. The other 4 patients who received VCR achieved complete remission 24, 30, 40 and 50 days from the beginning of the treatment. Total doses of VCR ranged from 2 to 6 mg in the deceased group, and from 6 to 14 mg in the cured patients. In our experience, VCR is a promising agent to treat TTP patients resistant to conventional plasma‐exchange and pharmacologic therapy.

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SummaryWe studied in a homologous system the procoagulant activity of human tumor cells cultured “in vitro” (1402 primary melanoma, Me 7110/2 metastatic melanoma, Hep G2 hepatoma and GLC1 small cell lung carcinoma) or of cells freshly isolatedfrom different human tumor tissues.Tumor cells cultured “in vitro” possessed and released a factor VII dependent procoagulant activity, which was inhibitedby concanavalin A and unaffected by iodoacetamide or HgCl2. The activity released by the cells of metastatic melanoma was higher than that released by the cells of the primary tumor. On the contrary, cancer cells isolated from tumor tissues possessed and released a factor VII independent activity which was inhibited by iodoacetamide or HgCl2 and was not modified by concanavalin A. Therefore, different methods for the preparation of tumor cell suspensions have to be used for the study of tumor procoagulants, since their expression depends very largely on the source of tumor cells. Furthermore, cultured human tumor cells are not an appropriate model for the “in vivo” procoagulant effect of tumor cells.