ISSN:1424-8832    

DOI:10.1159/000215050

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Human washed platelets were eluted from columns of Sepharose 4B linked to different preparations of collagen in order to evaluate cell adhesion. Collagen preparations characterized by low and high affinity toward platelets were identified. In our experiments, fibronectin purified from human plasma modified platelet adhesiveness, though not dramatically. When washed platelets, resuspended in a buffer containing fibronectin, were filtered on a low-affinity collagen-Sepharose, a significant increase in their adhesion occurred. A similar modification could be observed when platelets were allowed to adhere to the same collagen-Sepharose preconditioned with fibronectin. The effect of fibronectin was otherwise negligible when the high-affinity collagen was used for the experiments.

ISSN:1424-8832    

DOI:10.1159/000215051

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

The influence of hirudin on the thrombin-platelet reaction was studied by determination of thrombin-induced serotonin release from blood platelets. The dissociation constant for the thrombin-hirudin complex calculated from data obtained by measuring the platelet reaction (Ki 50 pmol/l) was in accordance with the value obtained by determination of fibrinogen clotting. Prevention of the effect of thrombin on platelets required the addition of hirudin in at least 10-fold molar excess. The release of serotonin could be immediately stopped by hirudin at any time when the special conditions for the reaction of thrombin with the tight-binding inhibitor and the receptors on the platelet surface were taken into account.

ISSN:1424-8832    

DOI:10.1159/000215052

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Studies of the turbidity profiles of diluted (1/55, v/v) normal plasma, thrombin activity free serum plus commercial fibrinogen, and 0.15 M NaCl, pH 7.4, plus commercial fibrinogen, activated by thrombin or reptilase and measured at 350 nm, have shown that the latency time (LT) hardly varies for the fibrinogen concentration within limits of 0.03–0.15 mg/ml; however, it does vary for the thrombin concentration. The rate of gelation (RG) varies linearly with the fibrinogen (FG) concentration, conforming to the equation RG = 0.027 (FG)1.8; it hardly varies for thrombin concentrations greater than 0.50 NIH U/ml. On the other hand, RG values obtained for 0.46 NIH U/ml of thrombin or 0.92 BU/ml of reptilase show no significant differences. The variation in LT for the thrombin or reptilase concentration allows the rate of activation to be estimated, giving values of 5.9 × 10-12 and 3.2 × 10-12mol/U/s, respectively, for a fibrinogen concentration in plasma of 1.1 × 10-10 mol/ml. The mean value estimated for the ratio LT/FG in normal plasma is 35.76 ± 18.3 and 85.62 ± 18.3s mg-1 ml for activation by thrombin and reptilase, respectively. We have studied in normal plasma the parameters that define the gelation of fibrin as measured by turbidity curves and their variation according to the fibrinogen concentration. This permits us to establish the kinetics of fibrin gel formation and normal range

ISSN:1424-8832    

DOI:10.1159/000215053

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

The effects of standardized venous occlusion (VO) on factor VIII-von Willebrand factor (F VIII-VWF) components (F VIIL·C, F VIIIR:AG, F VIIIR:RCof) and on fibrinolytic activity were investigated in 45 healthy subjects, in 28 women on oral contraceptives, and in 78 patients with various chronic diseases (28 with peripheral arterial disease, 19 with liver cirrhosis, 13 with rheumatoid arthritis, and 18 with diabetes). All the three F VIII-VWF components showed highly significant increases, although not of the same magnitude, with consequent variations in the ratios between them. A significant activation of fibrinolysis was also demonstrated with both euglobulin lysis time (ELT) and diluted blood clot lysis time (DBCLT). A strong linear correlation between pre- and post-stasis values was recorded for all the F VIII-VWF components and for the two fibrinolysis tests. No significant relationship was, on the contrary, found between F VIII-VWF and fibrinolytic parameters

ISSN:1424-8832    

DOI:10.1159/000215054

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Spectrophotometric heparin assays which are based on the catalytic effect of heparin on either the inactivation of thrombin or that of factor Xa by antithrombin III, were adapted for use in a laboratory batch analyzer. Optimal conditions were determined for assays using the chromogenic substrates Chromozym-Th and S-2238 with thrombin, and S-2222 with factor Xa. Inactivation of the clotting enzyme by antithrombin III was stopped by addition of chromogenic substrate. Assays thus obtained appeared to be applicable in a wider range of heparin concentrations and were less dependent on plasma antithrombin III concentration that known manual spectrophotometric methods. The best results were obtained with the methods based on thrombin inactivation and applying a logarithmic reference curve.

ISSN:1424-8832    

DOI:10.1159/000215055

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Three automated spectrophotometric heparin assays were investigated. The day-to-day reproducibilities in routine laboratory use were compared with two commercial manual kits for heparin determination. Regression analysis of the activated partial thromboplastin time (APTT) on results of any of the heparin assays shows that the heparin concentration cannot be deduced from the APTT values found in patients receiving heparin. The automated heparin assays that employ thrombin and Chromozym-Th or S-2238 were found to be most suitable for routine heparin determination. Heparin concentrations obtained from assays based on factor Xa inactivation were not significantly different from those employing thrombin (p < 0.01), but revealed a wider standard deviation. The relationship between APTT and heparin level found was not related to the plasma antithrombin III concentration. The extra antithrombin III that is added in the assays had to be freed of heparin neutralising activity to obtain reliable estimates of the heparin concentration in the low range (0–200 U/l

ISSN:1424-8832    

DOI:10.1159/000215056

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

The applicability was investigated of automated spectrophotometric heparin assays and three clotting assays for determination of two low molecular weight (LMW) heparin fractions: Org 10172 and DxN10 and two infractionated commercially available heparins. The relative activity of the two commercially available heparins was similar in the anti-Xa assay, in the anti-IIa assay and in 3 clotting assays. The LMW heparins showed markedly different relative activity in all 5 assays. The activities of those heparin preparations relative to the standard heparin were compared in the 5 assays, but standardization against a standard heparin preparation appeared impossible. Methods of heparin determination can be used to monitor treatment with a heparin preparation only if the same preparation is used as a reference substance.

ISSN:1424-8832    

DOI:10.1159/000215057

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Factors II, IX, and X in the plasmas of 10 patients with ‘hemorrhagic disease of the newborn’ were investigated by means of electroimmunoassay and crossed immunoelectrophoresis (CIE). The biological activity was within 4.2–30 U/dl for factor II, 5.1–20 U/dl for factor IX, and 5.2–24 U/dl for factor X, whereas the immunological antigen was within 33–58, 25–50, and 35–60 U/dl, respectively. Thus, for all factors, 1.7 times more antigen than activity was present. The CIE pattern of factors II and IX in the presence of Ca++ ions clearly showed a biphasic precipitin arc, and in the absence of Ca++ ions, only one precipitin arc was observed. These results implied the presence of precursor proteins PIVKA-II and -IX in the plasma. However, even in the presence of Ca++ ions the CIE pattern of factor X antigen in the patient plasmas only showed a single precipitin arc with a slightly faster than normal electrophoretic mobility. PIVKA-II, -IX, and the abnormal factor X antigen (PIVKA-X) disappeared within 24 h after the patients were treated

ISSN:1424-8832    

DOI:10.1159/000215058

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Prekallikrein (Prekk), antithrombin III (ATIII), plasminogen and alpha2-anti-plasmin were evaluated in chronic active hepatitis and in liver cirrhotic patients and correlated with Normotest. Prekk, ATIII and plasminogen were significantly decreased in chronic active hepatitis as well as in liver cirrhosis. Alpha2-antiplasmin levels in chronic active hepatitis patients did not differ from controls; liver cirrhotic patients, on the contrary, showed significantly low values of alpha2-antiplasmin. Prekk, ATIII and plasminogen were significantly correlated with Normotest in both groups, but when cirrhotic patients were divided into the compensated and decompensated state only Prekk was correlated with Normotest in the decompensated state. The investigation seems to suggest that Prekk could be a reliable index for protein liver failure.

ISSN:1424-8832    

DOI:10.1159/000215059

出版商:S. Karger AG    

年代:1984

数据来源: Karger