British journal of haematology
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Randomized Controlled Trial Clinical Trial
Aprotinin reduces cardiopulmonary bypass-induced blood loss and inhibits fibrinolysis without influencing platelets.
Cardiopulmonary bypass (CPB) induces a bleeding defect which leads to enhanced blood loss. A double-blind study was carried out comparing aprotinin with placebo in patients undergoing re-operation for heart valve replacement. The results confirm that aprotinin is effective at reducing such loss. ⋯ However, aprotinin did not influence the change in platelet count, suppress beta-thromboglobulin release from platelets, prevent the inhibition of platelet function or influence the concentration of plasma glycocalicin during the study period. These observations confirm that CPB leads to a fibrinolytic state and less responsive platelets. This study also indicates that aprotinin-induced reduction in blood loss is associated with inhibition of plasmin-mediated fibrin digestion and that the mechanism by which aprotinin reduces blood loss is not via protection of platelets during CPB.
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It is unclear whether the changes in platelet function which are observed in systemic sclerosis are a primary characteristic of this disease or whether they occur secondary to vascular changes. Whole blood platelet aggregation was studied in 26 patients with systemic sclerosis, normal subjects matched for age, sex and secondary characteristics, 19 patients with Raynaud's disease and 19 patients with systemic lupus erythematosus. Plasma levels of fibrinogen, von Willebrand factor antigen and factor VIII:C were also measured. ⋯ Systemic sclerosis was associated with significantly raised levels of von Willebrand factor antigen and fibrinogen. On an individual patient basis, von Willebrand factor antigen was related to the severity of the disease whereas platelet sensitivity to collagen was not. In conclusion, this study suggests that the enhanced sensitivity to collagen which occurs in systemic sclerosis is due to a primary change in the platelet and that this change can combine with elevated levels of adhesive proteins.
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Comparative Study Clinical Trial Controlled Clinical Trial
Reduced coagulation activation following infusion of a highly purified factor IX concentrate compared to a prothrombin complex concentrate.
We have looked for evidence of coagulation activation in six subjects with haemophilia B by performing a single-blind active control cross-over study comparing a recently developed factor IX concentrate with a conventional prothrombin complex concentrate (PCC). Samples were obtained before infusion and at 0.25, 0.5, 1, 2, 4, 6, 12, 24, 36 and 48 h for assay of factor IX, prothrombin time, fibrinopeptide A (FPA), prothrombin fragment F1 + 2, D-dimer, thrombin-antithrombin complexes (TAT) and antithrombin III (ATIII). Following administration of the PCC there was evidence of coagulation activation in five of the six recipients for up to 6 h after the infusion. ⋯ There was no significant difference between the two products in respect of either recovery or half-life. This study provides further evidence that the new high purity preparations of factor IX concentrates produce significantly less coagulation activation than currently available PCCs. It remains to be established whether this will result in a corresponding reduction in thromboembolic complications in clinical use.
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The incidence of acute biphenotypic leukaemia has ranged from less than 1% to almost 50% in various reports in the literature. This wide variability may be attributed to a number of reasons including lack of consistent diagnostic criteria, use of various panels of antibodies, and the failure to recognize the lack of lineage specificity of some of the antibodies used. The morphology, cytochemistry, immunophenotype and cytogenetics of acute biphenotypic leukaemias from our institution were studied. ⋯ This study highlights the problems encountered in the diagnosis of acute biphenotypic leukaemia, some of which may be responsible for the wide variation in the reported incidence of this leukaemia. We suggest that the use of strict, uniform diagnostic criteria may help in establishing a more consistent approach towards diagnosis of this leukaemic entity. We also suggest that biphenotypic leukaemia is comprised of biologically different groups of leukaemia based on immunophenotypic and cytogenetic findings.
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A survey of 870 different adult blood samples (primarily from patients with non-haematological disorders) found that 269 (31%) had increased proportions (> 25%) and/or absolute numbers (> 1.0 x 10(9)/l) of morphologically-defined large granular lymphocytes (LGL), and/or phenotypically-defined NK-associated (NKa) cells. Of these, 112 were re-analysed at least 6 months after initial presentation and were classified as 'persistent' (92/112) or 'transient' (20/112) according to whether or not the original abnormality was still present. Lymphocyte counts in most patients with persistent abnormalities were within normal limits (18/92) or slightly increased (68/92), with only six having a lymphocytosis exceeding 10.0 x 10(9)/l. ⋯ Persistent neutropenia (n = 15) also appeared to be associated with primary abnormalities of CD8+NKa+ cells (12/15), with 10 of these additionally showing rearranged TCR genes. In contrast, persistently increased CD8dim+NKa+ and CD8-NKa+ components did not appear to phenotypically differ from their corresponding 'counterparts' in normal bloods or in patients with transient LGL/NKa+ abnormalities. This survey has therefore established that persistent LGL/NKa+ abnormalities are considerably more common than suggested in published work, that a high proportion of patients with expanded CD8+NKa+ components, with quite diverse clinical histories, show evidence of clonal lymphoid populations, and that the clonal nature of such disorders appears to be associated with abnormal NKa phenotypic patterns.