摘要:

The one-stage prothrombin time test for tissue thromboplastin activity was evaluated using the correction method. A strong influence of the intrinsic system was seen depending on the clotting time and the type of tubes. This test was unsuitable for quantitative comparison of thromboplastin activity of different preparations.Subsequently a two-stage assay for human thromboplastin is described using purified human factor VII, artificially prepared factor VII reagent, and a phospholipid suspension. The correction method, applicated to this two-stage assay, resulted in a rectilinear dose-response curve when the clotting times of a thromboplastin dilution series were plotted against the reciprocal of the concentrations. Using this test system it could be shown that thromboplastin from porcine tissue can activate human factor VII quite well, while that from bovine tissue cannot.

ISSN:1424-8832    

DOI:10.1159/000214168

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

A method for the determination in plasma of α2-macroglobulin-bound thrombin is described. α2-Macroglobulin-bound thrombin is precipitated from plasma by 13% polyethyleneglycol, and its amidolytic activity is assayed by using the chromogenic substrate benzoyl-Phe-Val-Arg-p-nitroanilide (S 2160). After thrombin addition to plasma, only about 1.7 % of the added thrombin activity was recovered in the α2-macroglobulin precipitate. It is suggested that the contribution of α2-macroglobulin to the antithrombin activity of normal plasma is of little releva

ISSN:1424-8832    

DOI:10.1159/000214169

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The in vivo effects of three cytotoxic agents – cytosine arabinoside, daunomycin and hydroxyurea on rat bone marrow megakaryocytes were studied, specifically the relative count, the type percentage and the morphology. All three agents caused thrombocytopenia, a decrease in the number of megakaryocytes relative to the nucleated bone marrow cells, and a decrease in the percentage of megakaryoblasts, associated with an increase in the percentage of granular megakaryocytes. A decreased lobulation of the megakaryocytes was observed following the administration of cytosine arabinoside and of daunomycin. Thrombosthenin, examined immunologically, remained detectable in the bone marrow smears throughout the various stages of megakaryocyte alteratio

ISSN:1424-8832    

DOI:10.1159/000214170

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

We have determined the minimal concentrations of 4 aggregating agents that were required to cause a 65–75 % increase in light transmission without disaggregation during the 5-min recording period in PRP samples of 14 neonates and 10 adults. We found, for example, that this degree of aggregation could be elicited in adult PRP by a mean value of 2.09 μM ADP, whereas similar aggregation of neonatal PRP required 5.16 μM ADP. Based on these figures, we observed that adult PRP was about 2.5 times more sensitive to ADP, at least 10 times to epinephrine and 2.3 times to collagen than neonatal PRP. However, neonatal PRP was approximately 20% more sensitive to ristocetin than adult PRP. By using concentrations of aggregating agents that caused comparable aggregation of neonatal and adult PRP, we noted comparable inhibition of aggregation in these samples by aspirin. While neonatal PRP was less sensitive than adult PRP to physiological aggregating agents, there was no evidence that the former was more susceptible to in vitro aspirin inhibit

ISSN:1424-8832    

DOI:10.1159/000214171

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Ditazole (4,5-diphenyl-2-bis-(2-hydroxyethyl)-aminoxazol) has been shown to be a strong in vitro inhibitor of human platelet aggregation brought about by release reaction inducers; in contrast, it did not significantly affect primary ADP-induced aggregation. Ditazole strongly inhibited the release of platelet-bound 14C-serotonin under the influence of Thrombofax, whereas it did not interfere with the transport and storage of serotonin in nonstimulated platelets. The effect of ditazole was not potentiated by acetyl-salicylic acid. Ditazole also inhibited ADP-reptilase clot retraction and modified thrombin-induced clot formation. The inhibition of platelet aggregation exerted by ditazole in plasma could be removed following gel filtration of platelets on Sepharose 2-B gel. This would indicate that ditazole does not act on platelets by a ‘hit and run’ mechan

ISSN:1424-8832    

DOI:10.1159/000214172

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The process of fibrin formation was systematically investigated in 25 patients with severe alcoholic cirrhosis. Results of functional tests are reported. A significant lengthening of the thrombin time was found which could not be completely attributed either to hypofibrinogenaemia or to an increase in physiological anticoagulants or to the presence of pathological antithrombins. A defect in fibrin polymerization was seen in the absence of significant levels of antipolymerizing agents. Indirect evidence pointed to an abnormal fibrinogen function. This was mainly suggested by the ‘polymerization curves’ of mixtures of normal and pathological plasmas and the changes in physico-chemical properties of the clot (optical and elastic properties; tensile strength). Altered synthesis in hepatocytes may lead to an ‘acquired dysfibrinogenaemia’ in the late stages of liver cirrhosis, although alteration of a normal fibrinogen molecule after secretion cannot be definitely e

ISSN:1424-8832    

DOI:10.1159/000214173

出版商:S. Karger AG    

年代:1977

数据来源: Karger