摘要:

Synthesis of prostaglandin endoperoxides was evaluated in paired maternal and cord blood samples. Platelets from mothers and neonates aggregated normally in response to arachidonic acid (AA). Cyclooxygenase activity was evaluated by. monitoring the incorporation of radioactivity into prostaglandin endoperoxide metabolites after incubation with 1-14C-AA. Thin layer radiochromatograms of methylated incubation products revealed three main peaks corresponding to 12-L-hydroxy-5,8,10,14-eicosatetraenoic acid, 12-L-hydroxy-5,8,10-heptadecatrienoicacid(HHT), and 8-(l-hydroxy-3-oxopropyl)-9,12-L-dihydroxy-5,10-heptadecadienoic acid (TXB2). Maternal and neonatal platelets incorporated similar amounts of radioactivity into HHT and TXB2. Radioimmunoassay for TXB2 in thrombin-clotted PRP revealed no significant differences between maternal and neonatal platelets. Since these metabolites are derived from cyclic endoperoxides formed by the action of cyclooxygenase on AA, we conclude that prostaglandin endoperoxide synthesis is fully developed in neonatal platelets. Mutual correction of collagen-induced platelet aggregation and ADP release was observed when equal volumes of neonatal and aspirin-treated adult platelet-rich plasma were mixed. Therefore, since neonatal platelets contain normal amounts of storage pool nucleotides, we also conclude that the defective secondary aggregation and release seen in neonatal platelets is caused by a failure in the release of AA from membrane phospholipids upon stimulation with collagen or epinephrine.

ISSN:1424-8832    

DOI:10.1159/000214402

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

β-Thromboglobulin (βTG), platelet factor 4 (PF4), fibrinopeptide A (FPA), lactic dehydrogenase (LDH), and platelet count were evaluated in patients with bioprostheses and prosthetic heart valves. βTG and PF4 were significantly elevated in both patient groups (p < 0.001), whereas FPA was normal. There was no significant difference in plasma concentrations of βTG and PF4 between patients with prosthetic heart valves and bioprostheses. LDH levels were significantly (p < 0.001) higher and platelet count lower (p < 0.001) in patients with prosthetic cardiac valves. The data indicate that bioprostheses do not cause haemolysis or activation of the coagulation system. The findings that the plasma concentration of platelet-specific proteins were elevated, support the assumption that both types of valves cause platelet dam

ISSN:1424-8832    

DOI:10.1159/000214403

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The cryofibrinogen of 27 patients was studied by SDS-polyacrylamide gel electrophoresis and immunochemical methods. Electrophoretic analysis of the isolated cryofibrinogens, as well as the proteins left after heat or thrombin defibrination, showed that cryofibrinogen is composed of two proteins, fibrin(ogen) and cold-insoluble globulin (CIg). A proportion of the fibrin(ogen) component formed stabilized oligomers interlinked through γ-γ dimerization. The degree of fibrin(ogen) proteolysis, as judged by measuring the α: γ ratio of the reduced samples, was very similar to that of the fibrinogen of the original plasma. The CIg:fibrin(ogen) molar ratio in the cryofibrinogens was 0.041 ± 0.018. The CIg and the fibrin(ogen) content of the cryofibrinogens were strongly correlated with the plasma CIg le

ISSN:1424-8832    

DOI:10.1159/000214404

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The activity of the inhibitor of activated Stuart factor (anti-Xa) was evaluated together with the activity of the antiactivator of plasminogen (antiplasminogen) and the amount and nature of the fibrinogen/fibrin degradation products (FDP), as indicators of the existence of the risk for hypercoagulability in patients with acute and recent myocardial infarction (AMI and RMI, respectively). The activity of anti-Xa was diminished in the AMI group with a p < 0.001. The antiplasminogen activity was increased in both groups with a p < 0.001; on the other hand, the amount of FDP was increased in the AMI patients and they were of the ‘early’ type, while in the RMI group the increase was not as marked, but the FDP were of the ‘late’ type. In both groups the euglobulin lysis time was very prolonged, while the plasminogen did not vary significantly. The tests described appear to be valuable tools for studying the status of the cardiovascular system during cardiac rehabil

ISSN:1424-8832    

DOI:10.1159/000214405

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Two inhibitors of urokinase were isolated from the extracts of the nuclei of peripheral pig leucocytes, by ion exchange chromatography and by gel filtration on Sephadex G-100 and G-150. Only the inhibitor with the higher molecular weight was isolated in the homogenous form, in a single polypeptide chain with molecular weight of 68,000, designated Inhibitor-3. This inhibitor has an isoelectric point from 4.4 to 4.5 and is stable in buffer solutions from pH 3 to 8, and belongs to the type of so-called fast reacting inhibitors.

ISSN:1424-8832    

DOI:10.1159/000214406

出版商:S. Karger AG    

年代:1981

数据来源: Karger