摘要:

The effect of serotonin on vascular fragility, visible as petechiae, was examined in antiplatelet serum-induced thrombocy topenic hamsters. Serotonin was administered intravenously or intraperitoneally, and following a single injection of 0.5 mg/l00 g body weight, a temporary inhibition of petechial formation for approximately 1 h was observed. Repeated serotonin injections maintained animals free of petechiae for the 4-hour period of administration. Plasma levels of serotonin and the effect of serotonin on cutaneous perfusion were not significant factors in the observed inhibition of petechiae. The data suggest that in normal animals platelet serotonin may contribute more to maintaining microvascular structural integrity than platelet adhesion.

ISSN:1424-8832    

DOI:10.1159/000214389

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Citrated, platelet-rich plasma from human, guinea-pig and rat blood was incubated at 37 °C with (8-14C)-adenosine at different concentrations (1, 3, 30, 100 µM) with continuous stirring. Nucleotides and nucleosides were separated by high voltage electrophoresis for 1 h in 0.05 M citrate buffer pH 4.5. The spots were eluted and radioactivity was counted. Labelled adenosine was taken up by platelets within a few seconds and radioactivity increased with time of incubation. Guinea-pig platelets incorporated labelled adenosine more slowly than the platelets of other species: after 3 min of incubation with 1 µM (8-14C)-adenosine, 43% of the total radioactivity was found, whereas human and rat platelets incorporated 73 and 72% of the total radioactivity, respectively. The kinetics of incorporation and of nucleotide formation by the enzyme adenosine kinase indicated that the Km was 72.46 µM and the Vmax was 0.85 µM/min in guinea-pig platelets; the Km was 5.06 µM and the Vmax was 00.14 µM/min in human platelets; the Km was 13.72 µM and the Vmax was 0.74 µM/min in rat platelets. The kinetics of deamination and nucleoside formation by adenosine deaminase indicated that the Km was 28.21 µM and the Vmax was 3.22 µM/mm in guinea-pig platelets; the Km was 26.40 µM and the Vmax was 1.41 µM/min in human platelets, but the Km was 60.25 µM and the Vmax was 1.49 µM/min in rat platelets. It was concluded that there is no correlation between the inhibitory activity of adenosine on ADP-induced aggregation in the various species and the rate of labelled adenosine incorporation

ISSN:1424-8832    

DOI:10.1159/000214390

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The rate of postoperative deep vein thrombosis was studied by the 125I-fibrinogen method in 35 patients after total hip replacement. 12 out of 18 patients treated prophylactically with hydroxychloroquine sulfate developed deep vein thrombosis compared with 11 out of 17 patients in the control group. Platelet aggregability was inhibited in vitro by high concentrations of hydroxychloroquine sulfate, but these concentrations were not obtained in vivo and platelet aggregation was not inhibited in patients treated with hydroxychloroquine sulfate (Plaquenil®)

ISSN:1424-8832    

DOI:10.1159/000214391

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

The laboratory control of low-dose heparin therapy is generally regarded as unnecessary. A laboratory study of the effects of low-dose heparin was performed using different methods: an amidolytic method and a method involving the inhibition of factor Xa in a coagulation test. Variations in partial thromboplastin time, recalcification clotting time, thrombin time and the plasma antithrombin HI levels were also studied. These tests were repeated (days 0, 1, 3, 8) in 27 women between the ages of 27 and 62 years who were undergoiing gynecological surgery. They received 5,000 IU of heparin either twice or thrice daily. There was no correlation between heparin levels in the blood and global clotting tests simultaneously performed. The plasma heparin levels varied between 0 and 0.15 IU/ml with both methods. A detectable heparin concentration on days 1, 3 and 8 was present in only half of the cases receiving the twice daily regimen. The plasma antithrombin III activity and concentration were not modified during treatment.

ISSN:1424-8832    

DOI:10.1159/000214392

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

In patients with liver cirrhosis, a close relationship was observed between the respective levels of antithrombin III and prothrombin, both below 50% in 20 out 27 patients. The absence of any thrombotic complication, despite low plasma antithrombin III, suggests that the preserved balance between the inhibitor and the zymogens of the inhibited enzymes could have a protective effect against thrombotic tendency.

ISSN:1424-8832    

DOI:10.1159/000214393

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Bovine plasma yields fibrinolytically inactive euglobulin fractions, even when prepared in the presence of dextran sulphate. Addition of flufenamate to these solutions only occasionally elicits a slight activity. However, highly fibrinolytic solutions are produced when euglobulins precipitated in the presence of dextran sulphate are exposed to chloroform. Evidence indicates that a plasminogen activator is formed, which subsequently converts plasminogen present in the fractions to plasmin. Bovine euglobulin fractions contain an inhibitor which seems to be specifically directed towards urokinase and not to plasmin or to tissue plasminogen activator. Its inhibiting capacity is decreased after treatment with chloroform.

ISSN:1424-8832    

DOI:10.1159/000214394

出版商:S. Karger AG    

年代:1981

数据来源: Karger

ISSN:1424-8832    

DOI:10.1159/000214395

出版商:S. Karger AG    

年代:1981

数据来源: Karger