It has recently been postulated that thrombophilia may have a role in the aetiology of Perthes' disease. The published reports, however, remain conflicting. In this study a retrospective analysis of the coagulation parameters was made in 47 patients with Perthes' disease and the results compared with the clinical data. Five patients with Factor V Leiden mutation were found (10.6%) and surprisingly four of them had a homozygous pattern. These four patients showed the most severe form of the disease, Catterall group IV, with flattening of the entire epiphysis, involvement of the metaphysis, shortening and broadening of the femoral neck, trochanteric overgrowth and developed mushroom-shaped aspherical laterally displaced femoral heads in dysplastic acetabula. We would like to suggest that the homozygous form of Factor V Leiden mutation has some role in the clinical course of Perthes' disease and particularly its most severe form.

Summary The PFA-100 instrument (Platelet Function Analyzer, Dade Behring) has been reported to be superior to the bleeding time (BT) as a screening test of primary hemostasis. However evaluation of this device has been principally limited to selected populations. The study’s aim was to determine testing performance in clinical practice, by comparing the PFA-100 to the BT for the identification of von Willebrand disease (VWD) and intrinsic platelet hypofunction. From 1998-2000, PFA-100 closure time (CT) for epinephrine-collagen (EPI) and ADP-collagen (ADP) cartridges and modified Ivy BTs were performed on outpatients referred for testing for suspected or known hemorrhagic diathesis (n=346). Evaluation included assays of von Willebrand factor and platelet aggregometry in addition to platelet flow cytometry and electron microscopy when indicated. The normal distribution of PFA-100 CTs was determined using blood samples from 61 normal donors studied on 155 occasions. Results show that thirty-four patients met the diagnostic criteria for VWD and 31 patients were diagnosed with congenital or acquired intrinsic platelet hypofunction. The sensitivity of the PFA-100 for identification of VWD was significantly better (p<0.01) than the BT with similar specificity. In contrast, the PFA-100 was comparable, but not superior to the BT for detecting platelet hypofunction. We conclude that the PFA-100 performance compares favor-ably to the BT for the identification of intrinsic platelet hypofunction in clinical practice with superior sensitivity for detecting VWD.Therefore, the PFA-100 could replace the BT for purposes of screening for VWD and intrinsic platelet hypofunction. When clinical suspicion is strong, testing should be supplemented with assays of von Willebrand factor and platelet aggregometry.

Recent reports seem to support the role of the thrombophilia and decreased fibrinolysis in the aetiopathogenesis of aseptic necrosis of bone. In the present study, haemostatic disturbances were analysed in adults (n = 49) and patients in childhood (Perthes disease) (n = 47) with aseptic necrosis of the femoral head. Fibrinolytic parameters (in vitro clot lysis, plasminogen, plasmatic plasminogen activator inhibitor-1 activity, D-dimer) along with lipoprotein (a) [Lp(a)] and fibrinogen were measured. von Willebrand factor, platelet activation and some thrombophilic factors (activated protein C resistance and factor V Leiden mutation, protein C, protein S activity) were also determined. Impaired fibrinolysis, an increased Lp(a) level along with slow clot lysis and increased platelet activation were found in adult cases. We detected five cases of factor V Leiden mutations (one heterozygotic and four homozygotic) among patients with Perthes disease. The clinical course of the heterozygous case was similar to the usual form of Perthes disease. The most severe form of Perthes disease has been observed in homozygous factor V Leiden mutation cases. The mutation of factor V Leiden per se probably does not induce the development of aseptic necrosis of bone tissue in childhood, but it does play a role in its acceleration. Homozygous factor V Leiden mutation definitely runs a more severe course. On the other hand, in adult cases, the disturbances of haemostasis, impaired fibrinolysis, elevated Lp(a) level, increased platelet activation and slight elevation of fibrinogen might have clinical relevance. Further studies should focus on proving the role of the haemostatic alterations in the pathogenesis of severe forms of aseptic bone necrosis. The use of antithrombotic drugs in order to slow the process of aseptic necrosis also has to be addressed in future surveys.

The development of clinically overt porphyria cutanea tarda (PCT) can be attributed to joint effects of genetic predisposition and environmental factors. Regarding exogen factors, studies from several countries published in the last years gave an account of significantly higher frequency of chronic hepatitis C virus (HCV) infection in PCT patients compared to the normal population. At the Department of Dermatology of University of Debrecen the prevalence of positive anti-HCV antibodies has been found in approximately 55% of PCT patients diagnosed from 1990 to 1999, which is comparable to the average prevalence rate seen in Southern-European countries. The majority of male patients were anti-HCV positive and consumed regularly alcohol, whereas every female patient had taken contraceptives. Liver enzymes were only slightly elevated in the majority of the patients and liver biopsy had to be performed only in three patients duo to chronic hepatitis. Our findings emphasise how important the screening of PCT patients for anti-HCV antibody considering that it might be important quo ad vitam for young men.

Liver plays central role in the synthesis and metabolism of the pro- and anticoagulant enzymes of blood coagulation. Acute or chronic liver failure frequently result in different bleeding phenomena. Thrombocytopenia due to hypersplenism and lack of haemopoietic factors seems to be common, but in spite of thrombocytopenia and more or less platelet malfunction thrombocytopenic bleeding is usually less prominent feature. Bleeding esophageal varices, clotting abnormalities with peritonejugular shunts may pose many difficulties in clinical practice. Transjugular intrahepatic shunt (TIPS) has been a major step forward treating refractory esophageal bleeding or ascites, however to keep the stent patent seems to be still unresolved. Along with the bleeding tendency or symptoms concommittant venous thromboembolic events are may not be considered as rare events in cirrhosis. Special problems are also coupled with ascites, which contains an almost full inventory of coagulation proteins, also with the medical and interventional therapy of Budd-Chiari syndrome, and other veno-occlusive conditions with or without transplantation.

Thrombotic events, increased tendency toward intravascular thrombosis and decreased fibrinolysis seem to be possible pathologic causes for aseptic necrosis of the femoral head (ANFH) in adults. This project was to study whether either increased platelet activation or decreased fibrinolytic activity and/or any other thrombogenic factor may be implicated in the evolvement of ANFH. The speed of the in vitro lysis was significantly lower in patients (both in primary and in secondary cases) compared with healthy controls. The platelet activation (measuring with beta TG) proved to be significantly higher in the primary group as well as in the secondary group compared with healthy controls. Lp(a) levels were elevated in primary and secondary cases. This alteration was more characteristic in the primary cases. Fibrinogen levels were also elevated in the primary group, but the difference was not significant. The data shown here may further support that hypofibrinolysis and increased thrombogenesis are major causes of ANFH. Early diagnosis of ANFH increases the chances of modifying the course of this disabling disease.

Because platelets interact with fibrinolysis in a complex manner, it can be expected that with abnormal platelet numbers and quality this interference can be even more profound. The aim of this work was to study the lysis-resistance of platelet-rich clots in diseases with high platelet counts: polycythemia vera (PV), essential thrombocythemia (ET) and to make comparison with polyglobulia (PG). Platelet-rich plasma (PRP) and platelet-poor plasma (PPP) were analyzed by an in vitro clot lysis test. Plasminogen activator inhibitor-1 (PAI-1) activity was measured in plasma and in the supernatants of the washed and gel-filtered platelets after activation by thrombin. The lysis showed decreased speed of PPP-clots in PV and ET. This phenomenon was even more marked in PRP-clots from PV and ET, but further increased lysis resistance after retraction was not observed in PV and ET, most likely due to abnormal platelet functions. Our results suggest that the fibrinolytic activity is reduced in PV and ET, and may play a role both in the increased aptitude for venous thrombosis and in the arterial complications. These are partly caused by higher plasmatic PAI-1 activity as well as by more active platelet PAI-1. The PAI-1 activity was significantly higher in the supernatants of the washed and gel-filtered platelets of PV after activation by thrombin compared with controls. Other factors might have influenced the reduced fibrinolysis.

L-arginine ahs received much attention in numerous aspects of the regulation of vascular tone and haemostasis. L-arginine seems to be capable to bind to plasminogen, too. The aim of the present paper is to investigate the action of L-arginine on in vitro plasmin generation and fibrino(geno)lysis by chromogenic, kinetic plasmin generation assay and electrophoretic analysis. The acceleration of tPA-induced plasmin generation in the presence of low concentration of L-arginine, along with augmentation of in vitro fibrinogenolysis have been documented. L-arginine may have a role in the modification of fibrinogenolysis, and this role should be considered if arginine is used as an element of some novel antithrombotic agents.

Results obtained by a simple in vitro clot lysis test in polycythemia vera, polyglobulia, essential thrombocythemia and chronic immun thrombocytopenic purpura are reported. Increased lysis resistance of the platelet-rich clots was demonstrated in polycythemia and essential thrombocythemia, ostensibly caused by the high plasma level of plasminogen activator inhibitor-1. Following retraction of platelet-rich clots no further increase of lysis-resistance occurred in polycythemia and essential thrombocythemia. This phenomenon is most likely due to abnormal platelet function. The well known thromboembolic complications may at least partly result from the impaired fibrinolysis in diseases with high platelet counts.

Pentamidine, a highly toxic drug, possesses RGD-peptide (Arg-Gly-Asp)-like antiplatelet actions. The objective of this investigation was to study the anticipated profibrinolytic and antiplatelet actions of pentamidine and of pentamidine (bearing guanidino-like groups)-related synthetic peptidomimetic compounds. Platelet aggregation inhibition was assessed using ADP, thrombin, collagen, arachidonic acid and epinephrine as inducers, by aggregometry. In vitro chromogenic plasmin generation tests and clot lysis assays were also performed. Two (assigned as D-2 and D-3) of the synthetic pentamidine-guanidino related molecules were able to inhibit platelet aggregation and simultaneously accelerate in vitro plasmin generation and clot-lysis in the nM range. These dual action antithrombotic agents now need to be tested further to assess their antithrombotic actions in vivo.

A severe thrombotic thrombocytopenic status, induced by heparin in a sixty-nine-year-old woman undergoing total hip joint arthroplasty, was treated by switching the anticoagulant therapy to coumarin, which induced skin necrosis. There appeared to be a possible causal relation between the severe immune reaction to heparin and the condition that predisposed to skin necrosis in the presence of coumarin. In patients who express a strong immune response to heparin, a different anticoagulant approach other than use of coumarin congeners appears to be justified.