Endothelin and PDGF do not stimulate peripheral blood monocyte chemotaxis, adhesion to endothelium, and superoxide production

Endothelin is a potent vasoconstrictory endothelial-derived peptide which can induce smooth muscle proliferation and therefore may be proatherogenic. Platelet-derived growth factor is also a potent mitogenic vasoconstrictory protein which is proatherogenic. We report that neither endothelin nor PDGF stimulate superoxide production, or monocyte adhesion to porcine aortic endothelial cell monolayers; additionally endothelin is not a chemoattractant factor for monocytes. If endothelin and PDGF are important in atherogenesis it is unlikely that a monocyte response to these mediators is involved.

Differences in bleeding time, aspirin sensitivity and adrenaline between acute myocardial infarction and unstable angina

STUDY OBJECTIVE - The objective was to measure platelet function in vivo (as cutaneous bleeding time), the role of catecholamines, and the effect of inhibiting thromboxane synthesis on bleeding time, in patients with myocardial infarction, unstable angina, and non-cardiac chest pain. DESIGN - Haemotological variables and plasma catecholamines were compared between patient diagnostic groups using the Kruskal-Wallis test, Conover's multiple comparison test, and Wilcoxon paired rank sum test. PATIENTS - 49 patients entered the study and 45 were assigned to three groups: myocardial infarction (n = 26), unstable angina (n = 9), and non-coronary chest pain (control) (n = 10). There were no significant differences between groups for age or sex. Patients with myocardial infarction smoked more than others. MEASUREMENTS and RESULTS - Compared to the controls, bleeding time in patients with myocardial infarction was shortened, while in unstable angina it was normal. Plasma adrenaline and noradrenaline concentrations were higher in the myocardial infarction group than in the unstable angina and control groups, but were not correlated with bleeding time. Bleeding time was remeasured 2 h after ingestion of 300 mg aspirin and increased in all subjects, especially in those with myocardial infarction, but it remained significantly shorter in the infarct group than in the comparison groups. Plasma adrenaline was inversely correlated with the bleeding time after aspirin in the infarct group. CONCLUSIONS - The shortened bleeding time may be an indicator of an increased prethrombotic tendency present in patients with myocardial infarction but not in those with unstable angina. The effect appears to be mediated by both thromboxane A2 and adrenaline.

Monocyte-lymphocyte discrimination in a new microtitre-based adhesion assay

A new, rapid and reproducible method is described for the quantification of in vitro monocyte adherence in microtitre 96-well ELISA plates. The assay is based on the measurement of the myeloperoxidase activity in monocytes that have adhered to either plastic or bovine/porcine aortic endothelial cells. The assay shows a linear response to monocyte concentrations over the range 5 x 10(4)-5 x 10(5) cells/well. The method provides good discrimination between monocyte and and lymphocytes and thus allows a study of mononuclear cell populations to be made. The assay works equally well with polymorphonuclear cells. The coefficients of variation are: intra-assay, 7%; interassay, 13%.

Treatment of multiple subcutaneous Nocardia asteroides abscesses with ciprofloxacin and doxycycline

We report on the successful use of oral ciprofloxacin and doxycycline in the treatment of multiple subcutaneous nocardial abscesses in an immunocompromised patient with active non-Hodgkin's lymphoma. This relatively inexpensive regimen allowed the patient to return home and was not associated with any significant side effects. The patient has shown no sign of relapse of her nocardial infection over an 8-month period on the above regimen.

The bleeding time is inversely related to megakaryocyte nuclear DNA content and size in man

The relation between the bleeding time and the megakaryocyte nuclear DNA content and size was evaluated in eleven consecutive patients with normal steady state thrombopoiesis undergoing thoracotomy. A statistically significant inverse correlation was found between the bleeding time and both megakaryocyte DNA content (r = -0.71, p less than 0.05), megakaryocyte total size (r = -0.58, p less than 0.05), megakaryocyte cytoplasmic size (r = -0.64, p less than 0.05) and megakaryocyte nuclear size (r = -0.58, p less than 0.05). The megakaryocyte total size and the megakaryocyte cytoplasmic size were statistically significantly larger in men than women (p less than 0.02 and p less than 0.03 respectively). Changes in the megakaryocytes in the bone marrow are associated with changes in primary haemostasis in normal individuals.