Tissue factor pathway inhibitor can interact with platelets.

Tissue factor pathway inhibitor (TFPI) regulates the extrinsic pathway of blood coagulation. However, there is no report on interaction between TFPI and platelets other than that by Tsuji, who found that whole blood anticoagulated with TFPI exhibited remarkable decrease in platelet count. Our study revealed that washed platelets suspended in modified Tyrode's buffer (8 mM CaCl2) containing TFPI exhibit platelet aggregation. However, platelets aggregation was observed without TFPI, but its increase and intensity were slow and weak, compared to that in the presence of TFPI. This aggregation was inhibited by anti-CD41 (anti-GPIIb) antibody. This finding suggested that TFPI promotes platelet aggregation.

Possible automatic cell classification of bone marrow aspirate using the CELL-DYN 4000 automatic blood cell analyzer.

In clinical hematology, the demand for bone marrow aspiration testing is increasing. However, conventional automatic blood cell analyzers cannot completely analyze erythroblasts, and evaluation has mainly been performed by visual examination (the microscopic method). Using the CELL-DYN 4000 automatic blood cell analyzer (CD4000) (Abbott Laboratories, North Chicago, IL), specific recognition and classification of erythroblasts by DNA staining is possible. In the present study, using bone marrow blood collected from normal subjects and patients with hematological malignancy, we classified cells by the microscopic method and with the CD4000, and compared the results. Good correlations were found for total nucleated cell count (TNCC), neutrophils, lymphocytes, erythroblasts, and the myeloid series to erythroid series (M/E) ratio. It is possible to detect blasts that emerge in patients with hematological malignancy using the blast flag system installed on the CD4000. Since all of the items can be analyzed in about 80 sec with the CD4000, cells in bone marrow aspirates can be classified faster with this apparatus than by the microscopic method. Therefore, analysis of bone marrow aspirates with this apparatus appears to be very useful not only for laboratory testing but also for clinical screening.

Hematology tests of blood anticoagulated with magnesium sulphate.

Venous blood treated with magnesium sulphate (MgSO4) at blood collection was used for hematology tests. Complete blood counts and automated leukocyte differentials were obtained using a hematology analyzer, and the results obtained for blood treated with MgSO4 were similar to those for blood treated with dipotassium ethylenediaminetetraacetic acid (EDTA K2). Coagulation tests such as activated partial thromboplastin time, platelet factor 3 availability and prothrombin time were dose-dependently affected by the use of MgSO4. Thrombin time was prolonged by addition of MgSO4, and fibrin concentrations determined by coagulometry tended to decrease with addition of MgSO4, although fibrin concentrations determined by the weighing method were unaffected by MgSO4. MgSO, was thus found to potently inhibit blood coagulation and can be used as an anticoagulant for hematology tests.