ISSN:0957-5235    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The radioimmunological determination (RIA) of primary prostaglandins (PGs) in serum and plasma was evaluated with gas chromatography / mass spectrometry (GC/MS). Human blood was stimulatedin vitroin the presence or absence of the specific thromboxane synthase inhibitor ridogrel. TxB2, 6-keto-PGFlα, PGE2, PGD2and PGF2αwere determined with RIA and GC/MS on the same samples. For GC/MS analysis, prostanoids were extracted and derivatized to their methoximepentafluorobenzyl-esrers-trimethylsilyl-ethers. An excellent correlation was observed between levels of all eicosanoids determined by RIA or GC/MS (r= 0.996–0.999) when plasma was spiked with known amounts of PGs and TxB2(2 - 500 ng/ml). In stimulated blood, with or without inhibition of thromboxane synthase, the correlation between RIA and GC/MS values remained good, except for 6-keto-PGFlα. RIA largely overestimated the levels of 6-keto-PGFlαand no significant correlation was found with levels detected by GC/MS. The results demonstrate the importance of corroboraring the reliability of RIA with GC/MS.

ISSN:0957-5235    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The 5-HT-induced shape change and subsequent aggregation of platelets provides a functional assay for 5-HT2 receptors. In the present study we describe a method to increase aggregometer sensitivity by digital conversion of the voltage produced by changes in light transmirtance through a platelet suspension, thereby allowing accurate analyses of the primary shape-change response. The pharmacology of 5-HT-induced shape change was then compared with that of [I]-iodoLSD binding in human platelets. 5-HT caused a dose-dependent change in platelet shape (maximum response 5 × 10–6 M, EC50 10–6 M). Furthermore, there was a significant correlation across a selection of drugs between IC50 values for inhibition of 5-HT-induced shape change and for inhibition of platelet binding of the 5-HT2 receptor ligand [I]-iodoLSD. These results support the hypothesis that 5-HT-induced shape change and [I]-iodoLSD binding in human platelets are mediated through the same receptor, and validate the methods of data acquisition described.

ISSN:0957-5235    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Detailed haemostatic changes were investigated during eight liver transplantations. The patients were divided into two groups; group 1 had minor operative bleeding (four cases) and group 2 had major bleeding (four cases). Group 2 had lower levels of platelets, fibrinogen, factor V (FV), and a2-antiplasmin than group 1, and the thromboelastography showed fibrinolysis. In both groups, plasma tissue-plasminogen activator levels rose slightly. After revascularization of the graft liver, reductions in the values of PT, fibrinogen, FV and FVII were noted, along with a prolongation of the PTT and an increase in thrombin – antithrombin III complex levels. Plasma levels of protein C, protein S, antithrombin III, and plasminogen remained relatively stable throughout the operation. These results show that the preceding fibrinolysis and subsequent superimposed activation of the clotting system are the main causes of coagulopathy during liver transplantation, which correlate with the amount of operative haemorrhage and the abnormalities found in haemostatic tests.

ISSN:0957-5235    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Thrombocytopenia has been reported in patients with type IIB von Willebrand's disease (vWd) during pregnancy. In the present work we report the behaviour of platelet count and von Willebrand factor (vWf) muitimers in a pregnant type IIB vWd patient who presented with mild thrombocytopenia in the steady state. The evolution of pregnancy was associated with a progressive decrease of platelet count which showed its lowest value two days before delivery (20 × 109/1). The tendency of the platelet count to decrease was suddenly reversed a few days later (77 × 109/1). At the same time, the vWf multimeric pattern showed a stria but inverse correlation with the platelet count. In fact, a progressive increase of low and intermediate sized vWf multimers, which proceeded until platelets reached their minimum level, was noted. A few days after delivery, concomitant with the prompt platelet increase, low and intermediate multimers became decreased.During pregnancy, the patient's platelets showed additional increased responsiveness to ristocetin but did not demonstrate spontaneous platelet aggregation (SPA). On the contrary, the patient's plasma, collected both during and after pregnancy, caused normal platelets to aggregate spontaneously. SPA appeared completely blocked by an anti-GPIIb - IIIa monoclonal antibody (MAb), which recognized the binding site for fibrinogen, vWf and fibronectin. In contrast, a MAb against ristocetin-induced vWf binding site on GPIb did not affect SPA.These findings suggest that the common stimulus or stimuli, responsible for the pregnancy-induced decrease of platelet count and improvement of vWf multimeric pattern in type IIB vWd is strictly related to pregnancy. The sudden increase of platelet count immediately after delivery, seems to suggest that the phenomenon might also be due to other phenomena besides the higher production of abnormal IIB vWf during pregnancy. In addition, the results suggest that the mechanism involved in platelet hyper-responsiveness to ristocetin in type IIB vWd could be different from that inducing SPA.

ISSN:0957-5235    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

PAI-L antigen, tPA antigen and thrombin - antithrombin III complexes (TAT) levels were measured in 10 males with stable angina and type-D diabetes mellitus and in 16 males with stable angina without diabetes or other risk factors (hyperfibrinogenaemia, hyperlipidaemia, diabetes, hypertension, smoking and obesity) known to increase PAI levels. Ten healthy men of equivalent age served as controls. Because only diabetics with coronary artery disease (CAD) showed a decreased fibrinolytic capacity, a second study was performed on the 16 non-diabetic CAD patients to determine whether submaximal workload induces significant changes of tPA and PAI levels. TAT levels were increased in CAD, and significantly so in the diabetic group. tPA levels were increased only in CAD patients without diabetes. PAI levels were significantly increased in diabetic CAD patients (5.26 ± 1.96 ng/ml) but not in the stable angina patients without diabetes (2.97 ± 1.44 ng/ml). ImmunologicaUy-reactive tPA released after exercise was higher in the 16 CAD patients without diabetes than in controls. Our data could indicate that in stable angina without diabetes there is no chronic latent activation of the clotting system, with no impairment of fibrinolytic activity. On the other hand, the presence of diabetes mellitus seems to influence the fibrinolytic capacity in CAD, particularly increasing PAI levels.

ISSN:0957-5235    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Urokinase plasminogen activator (uPA) is a serine protease implicated in cancer spread and is thus a potential prognostic marker for human cancers. The aim of this investigation was therefore to compare uPA activity and uPA antigen as prognostic markers in breast cancer. Patients with tumours containing high levels of either uPA activity or antigen, had a significantly worse disease-free interval and survival pattern than patients with low levels. However, uPA antigen was a stronger prognostic marker than uPA activity. It is concluded that uPA should be assayed by immunoassay when using this protease as a prognostic marker in breast cancer.

ISSN:0957-5235    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The changes in relevant haemostatic parameters during the course of ten orthotopic liver transplantation were studied when aprotinin was given intra-operatively. Increases of tissue-type (P= 0.008) and urokinase-type (P= 0.009) plasminogen activators during the anhepatic phase could be correlated with hyperfibrinolysis. Thrombin - antithrombin III complexes (TAT) increased after revascularization of the liver graft (P= 0.003). Parallel studies in the perfusate showed that TAT concentrations were 350% and protease inhibitor activities (antithrombin III, protein C) only 52% of the systemic circulation before reperfusion, suggesting that thrombin activation together with protease inhibitor consumption occurs during graft liver reperfusion. The relatively smaller increases in profibrinolytic paramerers and a lower blood loss when compared with other groups may be explained by aprotinin administration in our patients.

ISSN:0957-5235    

出版商:OVID    

年代:1991

数据来源: OVID

ISSN:0957-5235    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Charleston, South Carolina, USA has a rich history extending over 300 years. The plantations of the Carolina Low Country produced rice, indigo and cotton. Mosquitoes, which abounded in the wetlands, transmitted diseases such as Yellow Fever and epidemics occurred almost every year. African slaves, however, had a natural immunity to the disease and, together with the climate and the nature of the work, this shaped the economic and social system of the area. Physicians offered all sorts of cures to deal with the medical problems of the area and apothecaries also sold many nostrums including leeches. Newspaper advertisements reveal that these bloodsuckers were extensively used for many decades.

ISSN:0957-5235    

出版商:OVID    

年代:1991

数据来源: OVID