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11. |
Development of a method to separate lipoprotein‐bound and lipoprotein‐depleted tissue factor pathway inhibitor. Measurement of free tissue factor pathway inhibitor activity |
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Blood Coagulation and Fibrinolysis,
Volume 9,
Issue 7,
1998,
Page 637-644
F. Bridey,
C. Lacombe,
L. Sustendal,
D. Moatti,
F. Combe,
O. Mammès,
D. de Prost,
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摘要:
The aim of this study was to develop a method to separate lipoprotein-bound from lipoprotein-free tissue factor pathway inhibitor (TFPI) and to measure the TFPI chromogenic activity and antigen in both fractions. This was performed by ultracentrifugation of plasma, after increasing its density to 1.21 g/ml with potassium bromide. Blood was taken from nine volunteers before and after an injection of low-molecular-weight heparin. The ultracentrifugation procedure was adequate, since the mean cholesterol recovery was 91% and only 2% of the cholesterol remained in the lipoprotein-depleted fraction. No free TFPI protein was found in the lipoprotein-rich fraction. Moreover, the amount of free TFPI in the lipoprotein-depleted fraction was close to that found in plasma. Using this method, we confirmed that heparin does not induce an increase in bound TFPI and that the moderate increase in total TFPI antigen in plasma is entirely caused by the enhancement of free TFPI. We then applied the TFPI chromogenic assay to the lipoprotein-depleted fraction to assess the activity of free TFPI. The activity was 0.11 ± 0.03 and 0.36 ± 0.08 U/ml before and after heparin, respectively (a 3.6-fold increase) while the activity of bound TFPI did not increase at all. We suggest that this method may be an alternative to gel filtration for measuring free TFPI activity, and might be of value in the search for TFPI abnormalities in patients with thrombosis.
ISSN:0957-5235
出版商:OVID
年代:1998
数据来源: OVID
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12. |
Effect of plasma pooling on the International Sensitivity Index of prothrombin time systems |
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Blood Coagulation and Fibrinolysis,
Volume 9,
Issue 7,
1998,
Page 645-652
A. van den Besselaar,
E. Witteveen,
H. Mansfeld,
C. van Rijn,
F. van der Meer,
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摘要:
Guidelines set by the World Health Organization (WHO) state that in order to calibrate a prothrombin time system for International Sensitivity Index (ISI), freshly prepared specimens from 20 normal individuals and 60 patients receiving coumarin are required. These numbers are required to obtain a precise value of the calibration line slope when there is considerable scatter of individual data about the regression line. The scatter can be reduced by pooling individual plasma samples. In the present study, four pooled plasmas were prepared, one from 20 normal individuals and three from three groups of 30 patients receiving treatment with long-term oral anticoagulants. Prothrombin times were determined with four thromboplastins, HepatoQuick (rabbit thromboplastin combined with adsorbed plasma), Recombiplastin (recombinant human thromboplastin), Thromborel-S (human placenta), and Thromboplastin-C Plus (rabbit brain). Calibration line slopes were calculated for the six possible combinations of thromboplastins using the set of all individual plasma samples and the set of four pooled plasmas. In most comparisons, the WHO calibration model was appropriate, i.e. the line calculated for the patients' samples passed through the mean of the normals. The calibration line slopes obtained with the set of four pooled plasmas did not differ by more than 5% from the corresponding slopes calculated with the original individual plasmas. For some combinations of thromboplastins non-linear relations were observed both with the individual plasmas and with the pooled plasmas. We conclude that pooling individual plasmas does not significantly change the calibration relation between prothrombin times determined with the original individual plasmas. Freshly pooled plasmas can be used to determine the ISI of prothrombin time systems with an acceptable degree of precision.
ISSN:0957-5235
出版商:OVID
年代:1998
数据来源: OVID
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13. |
Platelet activation in patients with antiphospholipid syndrome |
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Blood Coagulation and Fibrinolysis,
Volume 9,
Issue 7,
1998,
Page 653-658
Y. Shechter,
Y. Tal,
A. Greenberg,
B. Brenner,
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摘要:
The binding of antiphospholipid antibodies to circulating platelets and the potential association with thrombocytopenia and platelet activation was investigated in 25 patients with primary antiphospholipid syndrome (APS). Fourteen patients had a platelet count above 150 × 109/l, and 11 patients had mild to moderate thrombocytopenia of 50–150 × 109/l. The presence of platelet autoantibodies was investigated by immunofluorescent binding. No correlation between the presence of autoantibodies on platelets and thrombocytopenia was found. The binding of antibodies in patients' serum and platelet eluates was investigated by performing enzyme-linked immunosorbent assays with phospholipids as antigens. In seven patients antibodies to negatively charged phospholipids were present in platelet eluates. Platelet activation was measured by flow cytometry using a fluorescein isothiocyanate (FITC) labeled monoclonal antibody to P-selectin (CD62). The binding of anti-P-selectin to patients' platelet surface P-selectin was not increased, compared with the binding to platelets obtained from normal donors. Platelet serotonin concentration in APS patients was significantly lower than that found in the platelets of normal controls. More studies are necessary to determine the exact role of antiphospholipid antibodies in the pathogenesis of thrombocytopenia, and to elucidate the cause of low serotonin levels in platelets of APS patients.
ISSN:0957-5235
出版商:OVID
年代:1998
数据来源: OVID
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14. |
Emphasis on congenital conditions predisposing to thrombosis should not make us disregard the importance of acquired factors |
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Blood Coagulation and Fibrinolysis,
Volume 9,
Issue 7,
1998,
Page 659-660
A. Girolami,
L. Scarano,
B. Girolami,
A. Marchiori,
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ISSN:0957-5235
出版商:OVID
年代:1998
数据来源: OVID
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15. |
Factor V variants, activated protein C resistance and venous thromboembolism |
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Blood Coagulation and Fibrinolysis,
Volume 9,
Issue 7,
1998,
Page 661-662
P. Simioni,
M. Kalafatis,
D. Manfrin,
D. Tormene,
A. Girolami,
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PDF (108KB)
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ISSN:0957-5235
出版商:OVID
年代:1998
数据来源: OVID
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16. |
The 20210 A allele of the prothrombin gene is not a risk factor for juvenile stroke in the Danish population |
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Blood Coagulation and Fibrinolysis,
Volume 9,
Issue 7,
1998,
Page 663-664
M. Gaustadnes,
N. Rüdiger,
J. Ingerslev,
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PDF (130KB)
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ISSN:0957-5235
出版商:OVID
年代:1998
数据来源: OVID
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17. |
The anticoagulant effect of antithrombin/heparin complex. A new screening test to detect a thrombophilic tendency? |
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Blood Coagulation and Fibrinolysis,
Volume 9,
Issue 7,
1998,
Page 665-666
P. Makris,
P. van Dreden,
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ISSN:0957-5235
出版商:OVID
年代:1998
数据来源: OVID
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18. |
Recurrent arterial thrombotic disease on young onset and protein S deficiency |
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Blood Coagulation and Fibrinolysis,
Volume 9,
Issue 7,
1998,
Page 667-668
H. Nakagami,
K. Kario,
T. Mitsuhashi,
H. Fujikawa,
U. Ikeda,
K. Shimada,
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PDF (145KB)
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ISSN:0957-5235
出版商:OVID
年代:1998
数据来源: OVID
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19. |
Abstracts of the meeting of the XVth International Fibrinogen Workshop Jointly Sponsored by The International Fibrinogen Research Society The Cleveland Clinic Foundation |
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Blood Coagulation and Fibrinolysis,
Volume 9,
Issue 7,
1998,
Page 669-669
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PDF (56KB)
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ISSN:0957-5235
出版商:OVID
年代:1998
数据来源: OVID
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20. |
3. New insights into the interaction of fibrinogen and thrombin derived from the X‐ray crystal structure of bovine meizothrombin‐des Fl in complex with PPACK |
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Blood Coagulation and Fibrinolysis,
Volume 9,
Issue 7,
1998,
Page 670-670
P.,
Martin B.,
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PDF (185KB)
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ISSN:0957-5235
出版商:OVID
年代:1998
数据来源: OVID
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