Megakaryocytes from the marrow of a patient with Glanzmann's thrombasthenia lacked GP IIb-IIIa complexes

Although it is recognized that glycoprotein (GP) IIb-IIIa complexes are deficient in platelets in Glanzmann's thrombasthenia, little is known of the origin of the defect. We have examined the megakaryocytes in a bone marrow aspirate obtained from a thrombasthenia patient during surgery. Analysis of platelet proteins by SDS-polyacrylamide gel electrophoresis confirmed the patient to be of the type I subgroup. The megakaryocytes were examined by immunofluorescence or by immunocytochemical procedures combined with electron microscopy. Antibodies used included the murine monoclonal antibody, AP-2 and the human allo-antibody, IgG L, both of which recognize determinants on GP IIb-IIIa complexes. Bound antibody was detected by anti-IgG antibodies coupled to fluorescein isothiocyanate or absorbed on gold particles. In the immunofluorescence studies, permeabilized megakaryocytes were identified by double staining using an antibody to von Willebrand factor (vWF). Whereas mature megakaryocytes and their small precursor cells from normal individuals were strongly fluorescent with AP-2 and IgG L, most vWF positive cells from the Glanzmann's thrombasthenia patient were negative and the remainder gave but a weak background fluorescence. Immunogold staining on the surface of marrow cells was severely reduced. Our results confirm a deficiency of GP IIb-IIIa complexes in megakaryocytes in thrombasthenia.     

A leg ulcer as manifestation of metastatic squamous cell vaginal carcinoma

Cutaneous metastasis of vaginal carcinoma is extremely rare. So far, the total number of reported skin metastasis of vaginal carcinoma is only one. We present another case with an unusual manifestation of vagina carcinoma metastasis: skin metastasis presenting as a leg ulcer on the lower leg.     

Influence of selected heparins on human neutrophil functions in vitro.

The effects of four heparin derivatives [unfractionated heparin (UFH) at 5-50 IU/ml, low molecular weight heparin (LMWH) at 2-20 IU/ml, pentasaccharide (Penta) at 5 IU/ml and a synthetic heparinoid (PPS) at 10(-6)-10(-5) M] on various polymorphonuclear (PMN) leukocyte end-functions (aggregation, chemotaxis, phagocytosis and burst) were examined. CR3 expression, actin polymerization and membrane surface charge were also studied to gain more insight on the mechanisms of the action of heparins on PMN. The different heparins were found to have rather different actions. PMN were found to be hyperreactive to PPS. Pentasaccharide hat no effect on PMN functions, while UFH and LMWH had intermediate reactivity, modulating responses in an adenosine-like manner. Interactions of heparins with PMN were attributed to biophysical properties of the molecules rather than to the presence of a specific sequence such as a pentasaccharide. Our results show that certain heparin derivatives, apart their well-known anticoagulant action, modulate polymorphonuclear leukocyte functions that may be involved in vascular injury.