Effects of thrombin produced in blood prior to mixing with anticoagulant on the platelet function and blood coagulation tests

The amount of thrombin produced in the withdrawn blood of healthy donors prior to mixing with anticoagulants was estimated with thrombin-antithrombin III complex (TAT) methods. No samples showed production of thrombin in the blood mixed with anticoagulants within 2 min. After 3 min or more incubation, four donors out of 14 showed elevation of TAT, and a technician could suspect trouble only in a case during taking blood. Although two samples with low thrombin production (5.8, 12 ng/ml, normal: less than 5 ng/ml) showed no changes of APTT or prothrombin time, samples with high thrombin production (74, 98 ng/ml) showed 1.4-2 sec shortening of APTT and 0.8-1 sec shortening of prothrombin time. Platelet counts and platelet volume showed no remarkable changes even when samples with large amount of thrombin were suspended in tubes containing EDTA-2 K. Plasma beta-thromboglobulin concentration was elevated in the blood containing high amount of thrombin and close correlation was observed amount of thrombin in the blood and the amount of plasma beta-thromboglobulin (r = 0.90, P value less than 0.001). Platelet aggregation induced by collagen was not influenced by amount of thrombin produced. ADP-induced aggregation was suppressed in 3 out of 4 cases with thrombin production although no close correlation was observed between maximal aggregation rate and the concentration of thrombin. As improper handling of blood samples including withdrawal of blood leads to misunderstanding of test results. So, blood samples only for these sensitive tests should be taken and mix with anticoagulants within 2 min.     

The effect of blast cells on blood coagulation in patients with acute leukemia

The authors studied the effect of blast cells on coagulation of blood in patients with various forms of acute leukemia. It was found that blast cells are capable of producing a hypocoagulation effect on blood coagulation through primary activation of fibrinolysis. This property of blast cells did not depend on the form of acute leukemia.     

Activation of the tissue factor pathway of blood coagulation in patients with chronic urticaria

BACKGROUND: In patients with chronic urticaria (CU), plasma shows signs of thrombin generation and autologous plasma skin tests score positive in as many as 95% of cases. OBJECTIVE: To evaluate the initiators of blood coagulation that lead to thrombin generation and fibrinolysis in CU. METHODS: Activated factor VII, activated factor XII, fragment F(1+2), and D-dimer plasma levels were measured in 37 patients with CU and 37 controls. Skin specimens from 10 patients with CU and 10 controls were tested for tissue factor immunohistochemically. RESULTS: Mean F(1+2) levels were higher in patients than controls (2.54 [SD 2.57] nmol/L vs 0.87 [0.26] nmol/L; P < .001); disease activity was moderate or severe in 9 of 11 (82%) and 9 of 26 (35%) patients showing high or normal F(1+2) levels, respectively (P < .025). Mean D-dimer plasma levels were higher in patients than controls (329 [188] ng/mL vs 236 [81] ng/mL; P < .01); disease activity was moderate or severe in 6 of 8 (75%) and 11 of 29 (38%) showing elevated or normal plasma D-dimer levels (P = NS). Factor VIIa levels were higher in patients than controls (2.86 ng/mL [0.66] vs 1.97 ng/mL [0.65]; P < .001). Activated factor VII and F(1+2) levels were correlated (r = 0.529; P = .008). Tissue factor reactivity was observed only in CU skin specimens. CONCLUSION: The extrinsic pathway of clotting cascade is activated in CU. Disease severity is associated with the activation of the coagulation cascade. CLINICAL IMPLICATIONS: The involvement of the coagulation pathway in CU opens new perspectives for a better understanding of the pathogenesis and, possibly, for the treatment of this disease.     

Abnormalities of in vitro immunoglobulin synthesis by peripheral blood lymphocytes from patients with essential mixed cryoglobulinemia

Peripheral blood mononuclear cells from patients with essential mixed cryoglobulinemia (EMC) were studied for their ability to differentiate into cells containing cytoplasmic immunoglobulins (Ig) and to synthetize Ig after in vitro pokeweed mitogen activation. EMC lymphocytes showed a significant defective differentiation and Ig synthesis compared to normal controls. Coculture experiments carried out mixing enriched normal T- and EMC B-cell suspensions, and vice versa, showed that (a) the EMC B-cell-defective Ig synthesis still persisted after removal of suppressor activity by irradiation, both with autologous and with normal allogeneic T suspensions and (b) EMC T cells displayed a less efficient activity in helping Ig production by normal B lymphocytes. A comparable, reduced response was also found after activation with Staphylococcus aureus strain Cowan I. Taken together these results seem to indicate that in essential mixed cryoglobulinemia an impaired T-cell helper activity coexists with a B-lymphocyte impairment. The significance of these abnormalities in the pathogenesis of EMC is discussed.     

Evaluation of coagulation tests in mouse plasma

The coagulation variables thrombin time (TT), activated partial thrombin time (APTT) and prothrombin time (PT), were investigated in mouse plasma. TT and APTT clotting times were determined using a KC10 coagulation analyser and test kits Dia Thrombin (bovine thrombin diluted to a concentration of 2.5 U/l) and Dia Celin-L (rabbit brain cephaloplastin, activated with complexed Kaolin), respectively. PT was determined with IL Test™ Hepatocomplex (rabbit brain thromboplastin and calcium ions) using an ACL 200. Furthermore, the test procedures were also used to assess the anticoagulant status of mice treated orally with Melagatran, a thrombin inhibitor. The results showed that the kits could be used successfully on mouse plasma to measure the effect of a thrombin inhibitor on haemostasis.     

Abnormalities of fibrinolytic parameters in patients with myeloproliferative diseases

Thrombotic events are common in patients with myeloproliferative disorders. Since abnormalities in the fibrinolytic system have been reported in patients with thrombotic phenomena, we have evaluated fibrinolytic parameters in 48 polycythaemia vera (PV) patients, 25 myelofibrosis (MF) patients and 30 healthy controls. The following parameters were determined: plasminogen, α2-antiplasmin, tissue plasminogen activator (t-PA) antigen and plasminogen activator inhibitor (PA-1). High levels of t-PA antigen were found in the 2 patients groups-mean of 8.2 ng/ml and 8.7 ng/ml for the PV and MF patients respectively as compared to a mean of 4.3 ng/ml in the controls. Significant difference was also found between the mean levels of PA-1 in the PV and MF groups - 14.8 U/ml and 16 U/ml respectively and the control group-7.3 U/ml. No differences in PAI, t-PA, plasminogen and α2-antiplasmin were found when PV patients with and without a history of thrombotic complications were compared. Our findings suggest that abnormalities of the fibrinolytic system are a common feature in patients with myeloproliferative disorders. However, no correlation could be made between these parameters and the occurence of thrombotic events.     

ThinPrep Pap tests in patients with endometrial cancer: a histo-cytological correlation

The aim of this retrospective study was to correlate cytological diagnoses of endometrial cancers in ThinPrep Pap tests with the histological diagnoses. ThinPrep specimens from 67 patients within 12 mo of the histological diagnosis of endometrial cancer were studied. Of this study sample, 89.6% had abnormal Pap tests. Abnormal Pap tests occurred in 96.8, 68.4, and 100% of patients with grades 1, 2, or 3 endometrial cancers, respectively. Of patients with endocervical involvement, 88.9% had positive or suspicious Pap tests, compared with 41.1% without endocervical involvement (LR = 7.85, P < 0.01). Of patients with > or =50% myometrial invasion, 78.9% had positive or suspicious Pap tests, compared with 34.8% with less than 50% invasion (LR = 10.97, P < 0.01). Positive or suspicious Pap tests were found in 59.5 and 32.1% of those with tumors > or =3 cm or <3cm, respectively (LR = 4.85, P < 0.05).