[Congenital vascular malformations (Hauert disease)]. / Angiodysplastische Arthropathie ("Hauert disease").

Patients with congenital vascular malformations often suffer from arthralgia, especially of the lower limbs. This orthopaedic disease pattern is defined as destructive, angiodysplatic arthritis or Hauert disease and leads to very early destruction of the joints. By presenting diagnostic and therapeutic algorithms, Hauert disease is emphasized as a possible differential diagnosis in order to minimize the risk of an incorrect diagnosis which might lead to under-, over-, or even incorrect treatment. A minimally invasive transathroscopic therapy in the early stages can lead to significant improvement of symptoms and prevention of progressive joint destruction.

C1 inhibitor cross-linking by tissue transglutaminase.

C1 inhibitor, a plasma proteinase inhibitor of the serpin superfamily involved in the regulation of complement classical pathway and intrinsic blood coagulation, has been shown to bind to several components of the extracellular matrix. These reactions may be responsible for C1 inhibitor localization in the perivascular space. In the study reported here, we have examined whether C1 inhibitor could function as a substrate for plasma (factor XIIIa) or tissue transglutaminase. We made the following observations: 1) SDS-polyacrylamide gel electrophoresis and autoradiography showed that C1 inhibitor exposed to tissue transglutaminase (but not to factor XIIIa) incorporated the radioactive amine donor substrate [(3)H]putrescine in a calcium-dependent manner; 2) the maximum stoichiometry for the uptake of [(3)H]putrescine by C1 inhibitor was 1:1; 3) proteolytic cleavage and peptide sequencing of reduced and carboxymethylated [(3)H]putrescine-C1 inhibitor identified Gln(453) (P'9) as the single amine acceptor residue; 4) studies with (125)I-labeled C1 inhibitor showed that tissue transglutaminase was also able to cross-link C1 inhibitor to immobilized fibrin; and 5) C1 inhibitor cross-linked by tissue transglutaminase to immobilized fibrin had inhibitory activity against its target enzymes. Thus, tissue transglutaminase-mediated cross-linking of C1 inhibitor to fibrin or other extracellular matrix components may serve as a mechanism for covalent serpin binding and influence local regulation of the proteolytic pathways inhibited by C1 inhibitor.

Surface grafting onto template-assembled synthetic protein scaffolds in molecular recognition.

Creating functional biological molecules de novo requires a detailed understanding of the intimate relationship between primary sequence, folding mechanism, and packing topology, and remains up to now a most challenging goal in protein design and mimicry. As a consequence, the use of well-defined robust macromolecules as scaffolds for the introduction of function by grafting surface residues has become a major objective in protein engineering and de novo design. In this article, the concept of scaffolds is demonstrated on some selected examples, illustrating that novel types of functional molecules can be generated. Reengineered proteins and, most notably, de novo designed peptide scaffolds exhibiting molecular function, are ideal tools for structure-function studies and as leads in drug design.

Clopidogrel loading dose regimens: kinetic profile of pharmacodynamic response in healthy subjects.

Clopidogrel, a potent novel platelet ADP-receptor antagonist, induces a significant inhibition of ADP-induced platelet aggregation. Maximum inhibition of 40 to 50% is observed 2 to 5 hours after a single 400 mg dose. The same level of inhibition is achieved with 75 mg once daily at steady state, i.e., after 3 to 7 days of repeated dosing. Based on these data, two studies were undertaken to investigate whether a treatment regimen comprising a large initial dose (loading dose) of clopidogrel, followed by daily doses of 75 mg, might provide a sustained steady-state level of inhibition of platelet aggregation induced by 5 microM of ADP within hours after first dosing. In one study, 10 healthy male subjects received a 375 mg loading dose of clopidogrel on day 1, then daily doses of 75 mg from day 2 to day 10. Mean inhibition of platelet aggregation, already significant at 30 minutes, reached 55+/-8.2% (+/-SEM) at 60 minutes, and a maximum of 80+/-3.6% at 5 hours. No further significant change was observed between 5 hours and 24 hours, and from day 2 through day 10 with subsequent daily doses of 75 mg. In the second study, conducted according to a randomized, single-blind design, four parallel treatment groups of nine healthy male subjects received a loading dose of 75 mg, 150 mg, 225 mg, or 300 mg of clopidogrel on day 1, respectively, and 75 mg once daily from day 2 to day 5. Mean (+/-SD) inhibition of platelet aggregation over the 2 to 24 hours post-loading dose period was 22+/-14.5%, 21+/-13.4%, 35+/-20.6% and 31+/-13.3%, respectively. On day 5, it was 48+/-14.7%, 33 +/-14.1%, 51+/-15.7% and 40+/-10.9% for the 75, 150, 225 and 300 mg loading dose groups, respectively. The smallest day 1 to day 5 difference was observed for the 300 mg group and the largest for the 75 mg group, indicating that the development of the full inhibitory effect of clopidogrel was faster with the loading doses higher than with 75 mg, and fastest with the 300 mg loading dose. These data and those of previous studies indicate that a dose of 300 to 400 mg produces a rapid onset of the pharmacodynamic action of clopidogrel, with levels of inhibition close to steady-state reached within 2 hours.

Formation and properties of C1-inhibitor polymers.

Heating of the serpin C1-inhibitor above 55 degrees C induced the formation of inactive polymers. Western blotting of non-denaturing gels showed that the polymers bound to the conformation specific monoclonal antibody 4C3, suggesting that a similar conformational change to that occurring in complexed or cleaved inhibitor had taken place. N-Terminal analysis of tryptic peptides which bound to 4C3 showed that the epitope resides within residues 288-444, a region which includes parts of beta-sheets A and C. alpha 1-Antichymotrypsin, alpha 2-antiplasmin, angiotensinogen and thyroxine binding globulin also polymerised on heating, indicating that this is a property of many serpins.

Streptokinase and rt-PA activate platelets by a different way: implications on the rethrombosis rate after their administration in myocardial infarction.

The natural history of acute myocardial infarction has been dramatically changed by the advent of thrombolytic treatment, with a 30% mortality reduction, a better recovery of ventricular function, and a better quality of life. This treatment notwithstanding, failure or delay in achieving reperfusion, along with reocclusion and bleeding, still worry clinicians and challenge researchers to improve thrombolytic regimens and concomitant antithrombotic treatments. Platelet activation, at least in part because of thrombolytic treatment itself, plays a pivotal role in the pathogenesis of resistance to lysis and rethrombosis. The aim of this study was to compare in vitro the effects on platelets of therapeutic concentrations of streptokinase (SK) and recombinant type plasminogen activator (rt-PA). The effects of plasmin and thrombin were also studied as a reference. Fluorescence flow cytometry was used to evaluate (1) fibrinogen binding and (2) surface expression of GMP-140, a sensitive marker of platelet release reaction. Platelet function was further studied by measuring the release of carbon 14-labeled serotonin, beta-thromboglobulin, plasminogen activator inhibitor-1 (PAI-1) and the generation of thromboxane (TxB2). We found that 10 nmol/L SK and 14 nmol/L rt-PA increased fibrinogen binding to platelets by 12 +/- 2 and 10 +/- 4 times, respectively (p = not significant). At the same concentrations, SK, but not rt-PA, also induced the platelet release reaction: surface expression of GMP-140 was increased by 6 +/- 1.5 times by SK and 1.3 +/- 0.2 times by rt-PA (p < 0.05). TxB2 production was not modified by plasmin and plasminogen activators. Our data showed that plasmin and SK stimulate fibrinogen receptor expression and platelet degranulation. Conversely, rt-PA, at concentrations up to 14 nmol/L, only promotes fibrinogen binding. These results, coupled with the less-pronounced lytic state induced by rt-PA, could explain the higher incidence of reocclusion accompanying rt-PA therapy in comparison with SK that occurs unless effective "adjunctive" antithrombotic treatment is used. Neither of the thrombolytic agents activates the arachidonate pathway. Thus aspirin is probably not an ideal agent to be used in conjuction with thrombolytic agents. We speculate that newer approaches, particularly RGD peptides and antibodies against GP llb/llla, might produce better results.

High levels of the shed form of L-selectin are present in patients with acute leukemia and inhibit blast cell adhesion to activated endothelium.

L-selectin is expressed by most leukocytes and mediates the initial step of adhesion to vascular endothelium. A feature of this adhesion receptor is to be shed from the cell surface. We report here the presence of high levels of the shed form of L-selectin (sL-selectin) in plasma from patients with acute leukemia. We also show that sL-selectin purified from acute leukemia plasma exhibits functional activity. The mean (+/- 1 SD) plasma level of sL-selectin among 100 healthy individuals was 2.1 +/- 0.7 micrograms/mL. This value was increased (> 2 SD above the mean) in 63% of 58 patients with acute lymphoblastic leukemia (ALL) and 59% of 93 patients with acute myelogenous leukemia ([AML] P < .001). Repeated measurements in 24 patients showed normal-range levels in 16 of 16 patients in complete remission and high levels in eight of eight patients with therapy-resistant acute leukemia or leukemia relapse. Furthermore, elevated sL-selectin levels were detected in cerebrospinal fluid of three patients with ALL suffering from a relapse limited to the central nervous system. Epitope mapping with monoclonal antibodies demonstrated that L-selectin shedding from leukemic blasts was accompanied by conformational changes of its epidermal growth factor-like domain. A functional role for sL-selectin purified from leukemic plasma was supported by its ability to completely inhibit L-selectin-dependent adhesion of blast cells to tumor necrosis factor-alpha (TNF-alpha)-activated endothelium in vitro. These results suggest that sL-selectin may have an important role in the regulation of leukemic cell adhesion to endothelium. In addition, monitoring of the sL-selectin level may be useful for evaluating leukemia activity, in particular for the detection of leukemia relapse.

Comparison of results of intravenous infusion of anistreplase versus streptokinase in acute myocardial infarction.

This randomized study compares the coronary perfusion rate in patients with acute myocardial infarction (AMI) treated with 2 different intravenous thrombolytic agents: streptokinase 1.5 million U given over 60 minutes and anisoylated human plasminogen streptokinase activator complex (anistreplase) administrated as a bolus of 30 U over 5 minutes. One hundred seventy-five patients (149 men and 26 women, mean age 54 years) have been included in this study. Eighty-nine patients were treated with anistreplase and 86 patients with streptokinase. AMI was inferior in 54 patients (61%) in the anistreplase group and in 54 patients (63%) in the streptokinase group. It was anterior in 35 (40%) and 32 (37%) patients, respectively. Coronary angiography and ventriculography were performed at a mean time (+/- SEM) of 207 +/- 11 minutes after the beginning of thrombolysis in 170 patients. A perfusion score grade of 2 or 3 according to the Thrombolysis in Myocardial Infarction trial was found in 63 patients (72%) in the anistreplase group and in 56 patients (68%) in the streptokinase group (p = NS). Severe bleeding occurred in 7 patients (8%) after anistreplase and in 6 patients (7%) after streptokinase. No cerebral hemorrhage occurred. Nine patients (5%) died during their hospital stay: 6 after anistreplase and 3 after streptokinase. It is concluded that intravenous administration of anistreplase or streptokinase is efficient and safe. Coronary patency 207 minutes after fibrinolysis, incidence of adverse events and mortality are similar in both groups.

[Acquired factor V inhibitor treated with intravenous immunoglobulins]. / Inhibiteur acquis du facteur V traité par immunoglobulines intraveineuses.

We report the appearance of a factor V inhibitor in an 82-year-old female patient following abdominal surgery. This anomaly was totally corrected following 9-day treatment with i.v. immunoglobulins (0.4 g/kg/day), which allowed a needed further surgical intervention to be performed without hemorrhagic diathesis. The activity of this inhibitor was partly reversed by the in vitro addition of immunoglobulins, suggesting a concentration-effect relationship. This finding supports the hypothesis that anti-idiotypic antibodies could play a role in the therapeutic effect of immunoglobulins in such situations.

[The value of anticardiolipin antibody assessment]. / Intérêt du dosage des anticorps anticardiolipine.

Anticardiolipin antibodies (ACL) are associated with the presence of several clinical conditions. To determine the clinical interest of their evaluation, we reviewed all the results of ACL determinations performed in our laboratory during 1990 and 1991. 266 analyses (232 patients) were carried out. Determinations of IgG and IgM type ACL were performed by ELISA. ACL values were positive or slightly positive in 40% of the analyzed samples. Diagnosis was mentioned as the grounds for 212 requests (186 patients). ACL were positive (> m + 3SD) in about 40% of patients with autoimmune disease or with at least two of the following pathologies: autoimmune disease, venous or arterial thromboembolism, recurrent abortion.

Hypofibrinolysis in patients with a history of idiopathic deep vein thrombosis and/or pulmonary embolism.

An impaired fibrinolytic activity after a venous occlusion test is the most common abnormality associated with thomboembolic disease. To better characterize the causes of abnormal responses we have measured different fibrinolytic parameters, before and after 10 and 20 min of venous occlusion, in 77 patients with a history of idiopathic deep vein thrombosis and/or pulmonary embolism and in 38 healthy volunteers. The patients had a lower mean fibrinolytic response to venous occlusion than the controls and higher antigen levels of tissue-type plasminogen activator (t-PA:Ag) and plasminogen activator inhibitor type 1 (PAI-1:Ag). Before venous occlusion, PAI-1 levels were at a molar excess over those of t-PA in all patients and controls. After 20 min of venous occlusion, the release of t-PA from the vascular endothelium resulted in a molar excess of t-PA over PAI-1 in the majority of controls (72%) but only in a minority of patients (39%). To identify patients with fibrinolytic abnormalities, reference intervals (RI) for fibrinolytic activity, t-PA:Ag and PAI-1:Ag were established in healthy controls. None of the patients had low levels of t-PA:Ag, but 17 (22%) had elevated PAI-1:Ag levels before venous occlusion and 12 (16%) exhibited low fibrinolytic activity after 20 min of venous occlusion. Ten of these were among the 17 subjects with high PAI-1:Ag levels before venous occlusion. Thus, the measurement of PAI-1:Ag levels before venous occlusion (i.e. in samples taken without any stimulation) is a sensitive (83%) and specific (89%) assay for the detection of patients with an impaired fibrinolytic response to venous occlusion.

[Hemophilia C, a deficiency of a contact phase protein which may involve a risk of hemorrhage]. / Hémophilie C, un déficit de la phase de contact qui peut entraîner un risque hémorragique.

Factor XI deficiency, also called hemophilia C, was first described in 1953. It is thought to constitute 7% of all disorders of the intrinsic pathway of blood coagulation. It represents the only deficiency of a contact phase protein associated with a bleeding tendency with widely variable expression. Eighteen members of 5 families with this deficiency have been investigated; only 3 exhibited a hemorrhagic diathesis: 2/4 homozygous (hemorrhages after surgical procedures and hematomas and after minor traumatism) and 1/10 heterozygous individuals (hematomas, epistaxis). All homozygotes had a prolongation of the PTT. The hemorrhagic tendency was higher among homozygous individuals (with very low factor XI activity), but 2 were asymptomatic. Heterozygotes may also bleed. This deficiency is found mainly in an Ashkenazy Jewish population. Our study shows that it occurs in an apparently autochthonous Swiss population. A detailed history and studies of other family members are necessary if there is suspicion of factor XI deficiency.

Reaction of acetaldehyde with human platelets.

Platelet function defects observed in chronic alcoholics are not wholly explained by the inhibitory action of ethanol on platelet aggregation; they are not completely reproduced either in vivo by short-term ethanol perfusion into volunteers or in vitro by the addition of ethanol to platelet-rich plasma. As acetaldehyde (AcH) binds to many proteins and impairs cellular activities, we investigated the effect of this early degradation product of ethanol on platelets. AcH formed adducts with human platelets at neutral pH at 37 degrees C which were stable to extensive washing, trichloracetic acid hydrolysis and heating at 100 degrees C, and were not reduced by sodium borohydride. The amount of platelet adducts formed was a function of the incubation time and of the concentration of AcH in the reaction medium. At low AcH concentrations (less than 0.2 mM), platelet bound AcH was directly proportional to the concentration of AcH in the reaction medium. At higher concentrations (greater than or equal to 0.2 mM), AcH uptake by platelets tended to reach a plateau. The amount of adducts was also proportional to the number of exposures of platelets to pulses of 20 microM AcH. AcH adducts formation severely impaired platelet aggregation and shape change induced by ADP, collagen and thrombin. A positive correlation was established between platelet-bound AcH and inhibition of aggregation. SDS-PAGE analysis of AcH adducts at neutral pH demonstrated the binding of [14C]acetaldehyde to many platelet proteins. AcH adduct formation with membrane glycoproteins, cytoskeleton and enzymes might interfere with several steps of platelet activation and impair platelet aggregation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hematological parameters and prognosis in established or imminent HELLP syndrome. Apropos of 12 case reports]. / Paramètres hématologiques et pronostic dans le syndrome de HELLP établi ou imminent. A propos de 12 observations.

We describe the clinical and biological characteristics of 12 pregnant women with the HELLP syndrome as defined by Weinstein in 1982 (H for hemolysis, EL for elevated liver enzymes and LP for low platelet count). The data demonstrate that this syndrome is an obstetric emergency threatening the lives of both mother and child. However, if delivery is prompt the prognosis is good. The suspicion of gestosis requires a hematological assessment (complete blood count and close examination of blood film, evaluation of hemostasis) as an essential component in therapeutic decisions.

[Isolated prolongation of the PTT: 2-year retrospective study]. / Allongement isolé du PTT: étude rétrospective sur 2 ans.

The hemorrhagic risk associated with isolated prolongation of the PTT has been evaluated in a 2-year retrospective study. Of the 60 cases thus found, a hemorrhagic risk was present in 15 patients of whom 7 had hemophilia A, 5 von Willebrand's disease and 3 factor XI deficiency. Among the other etiologies not associated with a bleeding tendency, there were 31 proved or suspected cases with inhibitors of the PTT, most of whom were children, 2 factor XII deficiencies, 2 prekallikrein deficiencies and 4 contact phase activations. Isolated prolongation of the PTT is therefore without specificity and needs further investigation of hemostasis to determine the associated hemorrhagic risk.

[Prekallikrein deficiency: apropos of 2 cases]. / Déficience en prékallicréine: à propos de 2 cas.

An isolated, considerably prolonged aPTT (117 and 112 sec respectively; normal range 26-36 sec) was discovered during the preoperative workup in 2 patients aged 48 and 66 years. Both had a negative personal and family history for bleeding. Levels of the intrinsic coagulation factors which potentially cause a bleeding risk (VIII, IX, XI) were normal, and an inhibitor of the aPTT could not be detected. Investigation of the contact phase revealed a severe functional deficiency (less than 1%) of prekallikrein (PK) which was diagnostic of the homozygous state. Complete correction of the aPTT after prolonged activation of the contact phase and after addition of 0.2 volume of normal plasma to the sample is suggestive of this diagnosis, which needs to be confirmed by determination of the functional PK. Though deficiency of PK does not carry a bleeding risk, it is important to identify such cases in order to avoid time-consuming investigations in a surgical emergency situation.

[The dual protective effect of fish oil in preventing coronary diseases]. / Le double effet protecteur des huiles de poisson dans la prévention des maladies coronariennes.

We studied the effect of incorporation of eicosapentaenoic and docosahexaenoic acid into the normal Western diet in nine human volunteers for 6 weeks. They received 1.5 g per day of omega 3-polyunsaturated fatty acids (W3-PUFA) for 3 weeks followed by 3 weeks with supplementation of 3.0 g per day. A control period of 3 weeks preceded PUFA supplementation. A significant effect on lipids was found in the total triglycerides and VLDL-triglyceride fractions (p less than 0.025). The ratio VLDL-triglyceride over HDL-cholesterol was also significantly diminished after 6 weeks of treatment (0.86 +/- 0.15 vs 1.01 +/- 0.19, p less than 0.02). Prolongation of the bleeding time was clearly demonstrated after 6 weeks of supplementation (10.6 +/- 1.3 min vs 6.2 +/- 0.6 min). Platelet aggregation stimulated by either ADP or collagen was significantly diminished after W3-PUFA supplementation (p less than 0.025 and p less than 0.005 after ADP and collagen respectively). The lag time of platelet aggregation was significantly prolonged (94 +/- 12 vs 56 +/- 2 sec, p less than 0.005) and the maximum speed reaction of the primary phase of the reaction was significantly diminished (1.3 +/- 0.2 vs 1.6 +/- 0.2 mm/sec, p less than 0.02). In conclusion, in the light of this study W3-PUFA supplementation leads to two different benefits in cardiovascular prevention. First, a significant diminution of total plasma triglyceride has been shown and, second, prolongation of the bleeding time and diminution of the platelet aggregation have been demonstrated.

Plasminogen activators in dextran sulfate-activated euglobulin fractions: a molecular analysis of factor XII- and prekallikrein-dependent fibrinolysis.

To elucidate the mechanism by which activation of the contact system of blood coagulation leads to expression of fibrinolytic activity, we have determined the molecular characteristics of the plasminogen activators present in dextran sulfate-treated euglobulin fractions by electrophoretic-zymographic analysis and specific immunoadsorption. In addition to free and protease inhibitor-bound tissue-type plasminogen activator (t-PA), dextran sulfate precipitates of euglobulins contained the complex formed between plasma kallikrein and C1-inhibitor, an indicator of prekallikrein activation. These precipitates also contained substantial fibrinolytic activity related to urinary-type plasminogen activator (u-PA). Autoradiographic analysis was then used to evaluate the cleavage of 125I-single-chain u-PA (prourokinase) in dextran sulfate euglobulins as well as after exposure to kallikrein or beta-factor XIIa. This analysis supported the conclusion that plasma kallikrein-mediated cleavage and activation of single-chain u-PA is the mechanism operative for the development of lytic activity in euglobulin precipitates following activation of the contact system.

Fibrinolytic and anticoagulant activity after a single subcutaneous administration of a low dose of heparin or a low molecular weight heparin-dihydroergotamine combination.

The anticoagulant and potential profibrinolytic effect of a combination of low molecular weight heparin with dihydroergotamine (LMWH-DHE) and of unfractionated heparin was studied in eight healthy volunteers. Each volunteer received a subcutaneous injection of either LMWH-DHE (1,500 U anti-Xa of LMWH + 0.5 mg DHE), unfractionated heparin (5,000 IU) or of placebo (saline) between 7 and 8 h in the morning on three different occasions. Anti-Xa activity, and fibrinolytic activity measured by the euglobulin clot lysis time (ECLT) and by the fibrin plate assay were determined before and at different times after administration of the three substances. Anti-Xa activity in plasma reached a maximum four hours after injection of both LMWH-DHE and unfractionated heparin. LMWH-DHE showed a better bioavailability when compared to unfractionated heparin; the anti-Xa activity peak was two and a half fold higher after LMWH-DHE despite injection of a three fold lower dose of anti-Xa units. The half-life of anti-Xa activity was approximately 4 hours for LMWH-DHE but only 90 min for unfractionated heparin. The fibrinolytic activity measured by ECLT as well as by fibrin plate assay, showed a significant increase during the day reaching a peak 8-12 h after injection regardless of the product administered (including the placebo). The profile of the diurnal fibrinolytic activity curve was identical for all three substances. The increase in fibrinolytic activity, observed after administration of LMWH-DHE or unfractionated heparin, was therefore not due to these drugs but reflected the circadian physiological fluctuation of fibrinolysis.