Two novel fibrinogen variants found in patients with pulmonary embolism and their families.

BACKGROUND: The occurrence of dysfibrinogen is quite rare in comparison with other hemostatic defects, specially in cases of venous thrombosis. OBJECTIVES: Fibrinogen is known to have multiple functions, which are not evaluated by simple coagulation testing. We have used gel electrophoresis to search for new mutations. PATIENTS AND METHODS: Specimens of purified fibrinogen from 217 consecutive patients with familial or recurrent or early thrombosis and from 490 control subjects were evaluated by electrophoresis. Plasma fibrinogen levels and coagulation-dependent tests (electromechanical and optical coagulometric determinations, immunological measurement, thrombin and Reptilase(R) times) were normal. RESULTS: Two novel familial variants were detected. For a 42-year-old patient, an in-frame 117 base pair insertion in the Aalpha-chain gene caused a 5-kDa mobility shift of the Aalpha chain. This corresponds to a 39 amino acid duplication in the connector domain (fibrinogen Champagne au Mont d'Or). This pattern was also found in the patient's mother and child. A second 31-year-old patient presented an extra band under non-reducing conditions, 30 kDa larger than HMW fibrinogen and reacting with antifibrinogen antibodies (fibrinogen Lozanne). A heterozygous 5909A-->G mutation was found on the Bbeta-chain gene leading to heterozygous Bbeta Tyr236--> stop codon. The predicted truncated Bbeta chain could participate in chain assembly. Two family members were also affected, one of whom had suffered early venous thrombosis. CONCLUSIONS: Electrophoretic testing of apparently normal fibrinogens can reveal new variants which may be clinically relevant.

Human plasma fibrinogen measurement derived from activated partial thromboplastin time clot formation.

Prothrombin time-derived measurement of fibrinogen (PTd) has already been described. Activated partial thromboplastin time-derived measurement of fibrinogen (aPTTd) has not yet been clearly defined. Using an MDA II coagulometer (Organon Teknika, Durham, North Carolina, USA), we have therefore compared fibrinogen levels determined with Clauss, PTd, and aPTTd assays and an enzyme immunoassay (EIA) in 172 samples. Of these, 47 were from pre-operative controls, 18 from patients with liver disease, 28 from patients with hyperfibrinogenaemia, 33 from patients treated with vitamin K antagonists, 22 from patients treated with unfractionated heparin and 24 from haemophilic patients. Within the normal range, interassay and intra-assay variations were comparable. For control samples, PTd, aPTTd and Clauss assays were well correlated, without any systematic error. EIA was also correlated but values were slightly higher (mean of difference = 0.24). Pathological samples showed an overestimation of fibrinogen when using PTd measurements in patients treated with vitamin K antagonists, as well as when using aPTTd measurements in patients presenting with factor VIII and factor IX deficiencies. These results indicate that, despite expected financial savings, aPTTd fibrinogen measurements should not be used without restriction. PTd and aPTTd fibrinogen determinations are provided without any additional cost. Their comparison with Clauss fibrinogen results may constitute a validation tool or have additional diagnostic utility (e.g. identifying polymerization abnormalities in case of dissimilar results).

Description of 10 new mutations in platelet glycoprotein IIb (alphaIIb) and glycoprotein IIIa (beta3) genes.

In this study we have used denaturing gradient gel electrophoresis (DGGE) for identifying sequence alterations in glycoprotein (GP) IIb and IIIa genes from 20 patients affected by Glanzmann's thrombasthenia. These patients were from 16 different families. Using computer modelling, we divided the promoters, coding sequences and flanking splicing regions, in 31 segments for the GPIIb gene and 19 domains for the GPIIIa gene. We were able to find a mutation potentially affecting GPIIb-IIIa expression or function in 16 patients out of 20. In six patients from three families, the gypsy mutation modifying the splice donor site of intron 15 of the GPIIb gene was detected. In the other patients, 10 novel mutations were characterised, which were located either in the GPIIb gene (nine cases) or in the GPIIIa gene (one case). The type of mutation was nonsense mutation (one case), missense mutation (five cases), small insertion of 1 bp (one case) and splicing modifications (three cases). Among these genetic events, three were directly responsible for Glanzmann's thrombasthenia, four were localised in regions known to be involved in GPIIb-IIIa complex expression and three mutations were potentially responsible for Glanzmann's thrombasthenia.

Factor IX gene analysis in 70 unrelated patients with haemophilia B: description of 13 new mutations.

Seventy unrelated patients suffering from haemophilia B have been screened for determining the molecular defect and for evaluating the spectrum of factor IX mutations in the Rhône Alpes region in France. Most patients were characterized with respect to factor IX antigen and factor IX coagulant activity. We have used denaturing gradient gel electrophoresis to obtain a full scanning of the whole coding, promoter, and exon flanking sequences of the factor IX gene. This technique enabled us to determine the molecular defect in 68 out of 70 families (97%), and the mutation was further identified in the two last patients with a direct sequencing of the gene. A total of 2 complete gene deletions in patients with antifactor IX inhibitor, 6 small insertions/deletions and 62 point mutations were found. Two of these nucleotide substitutions (Arg145His and Ala233Thr) were detected in 21 patients (30%) suggesting the existence of a local founder effect. Thirteen mutations were previously undescribed, including 7 missense mutations. The detection of mutations in patients affected with haemophilia B may shed some light in the structure-function relationship of factor IX molecule within the coagulation system.

Safety and efficacy of three arthroscopic procedures using Holmium: Yag laser in two high-responder haemophiliacs.

We report here on the efficacy and safety of three arthroscopic procedures using a Holmium: Yag laser in two high-responder haemophiliacs. The two patients were treated with an activated prothrombin complex concentrate (FEIBA; Immuno, Vienna, Austria). Treatment was started just before surgery and continued for 4-8 days. On one occasion antifibrinolytics were concomitantly used without thromboembolic complication. Post-operative blood loss was slight, joint mobility was rapidly acceptable and full weight bearing without pain was possible on day 4. Such a procedure would appear to be superior to conventional arthroscopic synovectomy utilizing mechanical devices in haemophiliacs, because it might improve the quality of local haemostasis and the rapidity of post-operative recovery. In addition, it is also the technical procedure of choice in haemophilic patients with inhibitors who need synovectomy.

Thrombolysis with intravenous rtPA in a series of 100 cases of acute carotid territory stroke: determination of etiological, topographic, and radiological outcome factors.

BACKGROUND AND PURPOSE: Although new, large, double-blind, randomized studies are needed to establish the efficiency of intravenous thrombolysis, open trials of sufficient size may also provide novel data concerning specific outcomes after thrombolysis. METHODS: An open study of intravenous rtPA in 100 patients with internal carotid artery (ICA) territory strokes between 20 and 81 years of age, with a baseline Scandinavian Stroke Scale (SSS) score of <48 at entry was conducted. Inclusion time was within 7 hours after stroke onset. rtPA (0.8 mg/kg) was infused for 90 minutes, with an initial 10% bolus. Heparin was given according to 3 consecutive protocols. The SSS evaluation was done on days 0, 1, 7, 30, and 90. CT scan was performed before treatment, on days 1 and 7. Etiological investigations included echocardiography and carotid Doppler sonography and/or angiography. Outcome at 1 year was documented by SSS score, the modified Rankin Scale (mRS) score, and a 10-point invalidity scale. Multivariate logistic regression was used to identify predictors of poor versus good outcome. RESULTS: At day 90, 45 patients (45%) had a good result, defined as complete regression or slight neurological sequelae (mRS score of 0-1), 18 patients had a moderate outcome (mRS 2-3), and 31 patients had serious neurological sequelae (mRS 4-5). Six patients died, 2 with intracerebral hematoma after immediate heparin. Five of 11 patients (45.5%) treated between 6 and 7 hours had a good result. The overall intracerebral hematoma rate was 7%. Higher values of fibrin degradation products at 2 hours were observed in the subgroup with intracerebral hematomas. Significant predictors of poor outcome on multivariate logistic regression analysis were baseline SSS score of <15 (odds ratio [OR], 3.38; 95% confidence interval [CI], 1.07 to 10. 74; P=0.04), indistinction between white and gray matter on CT scan (OR, 6.59; 95% CI, 2.19 to 19.79; P=0.0008), and proximal internal carotid thrombosis (OR, 3.29; 95% CI, 0.99 to 10.95; P=0.05). CONCLUSIONS: Our study confirms the safety of intravenous rtPA at a dose of 0.8 mg/kg and suggests efficacy for this drug even within 7 hours. Outcome and hematoma rates were at least as favorable as for trials of therapy with a 3-hour time window. Subgroups with a poor prognosis include low baseline neurological score, baseline CT changes, and proximal ICA thrombosis. However, approximately 30% of patients with each of these characteristics show a good outcome, so their inclusion in future routine rtPA protocols is still justified.

Evaluation of coagulation equilibrium at baseline and during factor VIII and factor IX replacement in haemophiliacs.

We designed a prospective unicentre study to evaluate the safety and efficacy of continuous infusion of different factor VIII (FVIII) and FIX concentrates in haemophilia A (n = 9) and haemophilia B (n = 4) patients undergoing surgical procedures. This study was designed to assess the potential risk of developing thromboembolic complications during different types of surgery and to provide some comparative data with respect to continuous infusion of clotting factor concentrates. Heparin prophylaxis was not used in most cases. As pointed out by others, we did not find any significant changes in prothrombin fragment F1+2 and D-dimers during a pharmacokinetic study using a bolus dose of 50 U/kg of a very high purity clotting factor concentrate. Moreover, prothrombin F1+2 and D-dimer serial assays were also carried out postoperatively, and compared with levels in control non-haemophilic patients who had undergone similar surgery with heparin prophylaxis. In haemophilia patients, despite (in most cases) an absence of heparin prophylaxis, no thrombotic complications occurred, and neither the coagulation cascade nor the fibrinolytic system were significantly over-activated, compared with the control group. From a clinical standpoint, all patients achieved excellent haemostasis without clinical evidence of thrombosis. This study emphasizes the convenient and safe administration of highly-purified FVIII and FIX concentrates in haemophiliacs undergoing surgical procedures, and constitutes a small comparative database for the evaluation of new products.

Population pharmacokinetics of recombinant factor VIIa in volunteers anticoagulated with acenocoumarol.

This study establishes a population PK model for FVII clotting activity (FVII:C) after injection of recombinant activated factor VII (rFVIIa) to healthy volunteers. Twenty eight volunteers, anticoagulated with acenocoumarol, received one or two rFVIIa injections, with dose ranging from 5 to 320 microg/kg. The FVII:C kinetic was fitted to a 2 compartment model, with continuous "endogenous perfusion" mimicking endogenous activity. Estimated clearance was 2.4 1/h (20% inter-individual variability and 9% inter-period variability). The volume of distribution at steady-state appeared to be significantly dose dependent: 78 ml/kg for doses < or = 20 microg/kg and 88 ml/kg for doses > 20 microg/kg respectively, with 16% inter-individual variability. The dose producing 50% of the maximum drop of INR was estimated to be 2.2 microg/kg. The model will be used to better define the dosage regimen for future clinical developments.

Efficacy and safety of continuous infusion of Mononine during five surgical procedures in three hemophilic patients.

We report here five surgeries successfully performed with a continuous infusion of Mononine (Armour Pharmaceutical Company, Kankakee, IL) in three hemophilic B patients. Before surgery the patients received a bolus dose of 40 to 100 U/kg according to the type of surgery. This injection was followed by a continuous infusion of Mononine, with an infusion rate of 3.5-7 U/kg/hr in order to maintain a factor IX level between 50 and 100% during the whole surgery and the following 6 days. The infusion rate was further adjusted according to the type of surgery until hospital discharge. This method appears to be safe and efficient, since no abnormal bleeding occurred during surgery and none of the patients presented any thrombotic complication. However, this alternative to intermittent administration of factor IX should be standardized and precisely evaluated, regarding the level and the amount of factor IX required, and the cost of the infused material. In our hands, this cost was decreased by 30-40% compared to previous therapeutic schedules at our institution.

Anticardiolipin antibodies and giant cell arteritis: a prospective, multicenter case-control study. Groupe de Recherche sur l'Artérite à Cellules Géantes.

OBJECTIVE: To assess the prevalence and thrombogenic role of anticardiolipin antibodies (aCL) in giant cell arteritis. METHODS: Two hundred eighty-four patients with newly diagnosed temporal arteritis or polymyalgia rheumatica and 210 age- and sex-matched controls randomly selected from the general population were included in a multicenter, prospective case-control study. Blood samples were obtained at the time of diagnosis, data on initial clinical features were collected in a questionnaire, and temporal artery biopsy findings were reviewed by an experienced pathologist. RESULTS: Anticardiolipin antibodies were present in 20.7% of patients compared with 2.9% of controls (P = 1.45 x 10(-9)). The prevalence of aCL was higher in samples found positive for temporal arteritis than in those found negative on biopsy (31.2% versus 16.7%; P = 0.04), and was similarly higher in the biopsy-positive temporal arteritis group compared with the polymyalgia rheumatica and control groups. Although aCL were associated with thrombotic complications in univariate analysis, the positivity of the biopsy findings remained the only predictive variable in stratified analysis. CONCLUSION: In giant cell arteritis, aCL seem to function as reactive antibodies in relation to endothelial lesions.

Illegitimate transcription: its use for studying genetic abnormalities in lymphoblastoid cells from patients with Glanzmann thrombasthenia.

Glanzmann thrombasthenia is the most common inherited disorder of platelets that may induce severe bleeding complications. Molecular biology techniques have offered the possibility to assess the basis of this chronic haemorrhagic disease at the molecular level. However, the accessibility of mRNA in platelets is limited by the availability of the patient's blood samples and the relatively weak amount of this material in these cells. Taking advantage of the genetic phenomenon of illegitimate transcription, we have demonstrated that glycoprotein IIb and glycoprotein IIIa mRNA could be detected in lymphoblastoid cell lines issued from normal EBV-transformed lymphoblasts. We further analysed the sequences of the two glycoprotein transcripts in lymphoblastoid cell lines from two previously characterized patients presenting with Glanzmann thrombasthenia. The results showed that illegitimate transcripts presented similar molecular abnormalities to those found in platelets. These data demonstrated that the nucleotide sequences of illegitimate transcripts were identical to tissue-specific mRNA found in platelets. We applied this methodology to screen for the genetic defect in a new thrombasthenic patient, and found a homozygous nonsense mutation GCA-->TGA converting Arg8 to stop in the glycoprotein IIIa gene. This immortalized source of genetic material is therefore particularly useful for molecular genetic studies in inherited platelet disorders, avoiding repetitive and large blood samplings in frequently anaemic patients.

An unusual haemarthrosis in an HIV-seronegative haemophilia A patient.

We report the case of a severe haemophilia A patient with an anti-factor VIII antibody who presented with a thigh haematoma and 1 year later with an elbow haemarthrosis infected by Salmonella enteritidis. These two infections were treated by antibiotics. The probable origin of these infections seems to be an anal fistula. The occurrence of a septic arthritis due to Salmonella is rare, and to our knowledge has never been reported in HIV-negative haemophilic patients. The differential diagnosis of haemarthrosis and septic arthritis in a haemophilic patient is also discussed.

The effect of recombinant factor VIIa (NovoSeven) in healthy volunteers receiving acenocoumarol to an International Normalized Ratio above 2.0.

Vitamin K antagonists are most commonly used in long-term thrombosis prophylaxis and the use in patients with cardiovascular disease seems to be increasing. By interfering with the normal hemostatic mechanism, an increased risk of bleeding will arise and administration of human plasma or prothrombin complex concentrates may be necessary. It can be difficult to normalize hemostasis using plasma and prothrombin complex concentrates, because these may be associated with thromboembolic side-effects. The level of factor VII, one of the vitamin-K-dependent coagulation factors, decreases during oral anticoagulant therapy and the administration of recombinant factor VIIa normalizes the prolonged prothrombin time in warfarin-treated rats. After administration of acenocoumarol (International Normalized Ratio > 2), decreased levels of factor X and factor IX (19-46%), protein C (2-20%) and factor VII (4-17%) were found in 28 healthy volunteers. After one dose of recombinant factor VIIa (5, 10, 20, 40, 80, 120, 160, 240, or 320 microg/kg) the International Normalized Ratio and prothrombin time normalized, which may imply an effect on bleeding in individuals receiving oral anticoagulant therapy. The lowest dose (5 microg/kg) normalized the International Normalized Ratio for 12 h and doses > 120 microg/kg normalized it for 24 h. Fragment 1+2 stayed within its normal range in all dose groups, indicating that no systemic coagulation occurred.

Identification of new and known polymorphisms in glycoprotein IIb and IIIa genes by denaturing gradient gel electrophoresis.

Glycoprotein IIb and IIIa contain antigenic determinants involved in the potential production of allo- or autoantibodies directed against platelets, that may result in severe thrombocytopenia. Most of these epitopes appear to be supported by single nucleotide substitutions. We have used denaturing gradient gel electrophoresis (DGGE) to identify sequence variations within the promoter and the coding regions of the glycoprotein IIb and glycoprotein IIIa genes. Using genomic DNA from 60 unrelated normal individuals, we have amplified short domains that encompass the coding sequences and the exon-intron boundaries of both genes that were further separated according to their melting behaviour during the denaturant electrophoretic migration. Only the fragments with an abnormal migration pattern were sequenced. We confirmed the sensitivity of this method by recognizing both previously described Human Platelet Antigen polymorphisms and mutations affecting either the glycoprotein IIb or the glycoprotein IIIa genes in thrombasthenic patients. We also identified four other polymorphisms. Two were located in the glycoprotein IIb gene, involving intron 21 (C<-->G at nucleotide 10480) and first codon of exon 30 (codon GTC<-->GTT coding for residue Val 990), and two in the glycoprotein IIIa gene (exon 6 CCC<-->CCT coding for residue Pro 268; intron 14 C<--> T at position 37126). The screening of the GPIIIa promoter also revealed three different polymorphisms located at position-468 (A/T polymorphism), -425 (A/C polymorphism) and-400 (A/C polymorphism), which could influence the expression of the complex at the cell surface. Denaturing gradient gel electrophoresis appears to be a sensitive and specific technique for identifying polymorphisms and mutations in the GPIIb and GPIIIa genes.

A nonsense mutation in the GPIIb heavy chain (Ser 870-->stop) impairs platelet GPIIb-IIIa expression.

Glanzmann thrombasthenia (GT) is a rare autosomal recessive bleeding disorder, caused by a quantitative or qualitative defect of the GPIIb-IIIa integrin (alpha IIb beta 3), which functions as the platelet fibrinogen receptor. We report a case of type I GT due to a homozygous mutation resulting in Ser 870 to stop codon substitution. This residue is located near the proteolytic cleavage site of proGPIIb. The mutation results in a GPIIb truncated of 138 amino acids, including transmembrane and intracytoplasmic domains. Cotransfection of an expression vector containing the mutant GPIIb and wild-type GPIIIa showed that the mutant Ser 870-->stop GPIIb was able to associate to GPIIIa. However, this heterodimer failed to mature as shown by endoglycosidase-H digestion and was therefore not expressed at the COS-7 cell surface. This report is the first description of a homozygous nonsense mutation in the GPIIb gene and highlights the role of the GPIIb light chain.

Platelet-aggregation inhibition and hemodynamic effects of beraprost sodium, a new oral prostacyclin derivative: a study in healthy male subjects.

The antiaggregation and hemodynamic effects of the new prostacyclin analogue beraprost sodium were investigated in a randomized, placebo-controlled, double-blind clinical trial of Latin-square design. Twelve healthy Caucasian males randomly received 8-day oral treatments of 20, 40, and 60 micrograms of beraprost sodium and a placebo. One-week washout periods followed each treatment. Pharmacokinetic and pharmacodynamic measurements were performed on days 1 and 8 for each period of treatment. All three doses of beraprost sodium significantly inhibited platelet aggregation on day 8 (compared with placebo) during the 1st h after drug intake. Incubation of the 60-micrograms beraprost sodium samples with ADP (2, 5, and 10 microM) and collagen (1.25 micrograms/mL) decreased platelet aggregation by 10, 19, 16, and 6 +/- 4% (mean +/- SE), respectively, compared with placebo. No significant hemodynamic effects on blood pressure, heart rate, and digital pulse were observed. The 60-micrograms dose of beraprost sodium did significantly decrease the IRZ index (which may reflect the left ventricular pre-ejection period) on days 1 and 8. Some subjects experienced headache and facial flushing, effects that were dose dependent and reversible. Beraprost sodium at 20- to 60-micrograms doses exerts platelet antiaggregation (day 8 of therapy) and slight hemodynamic (days 1 and 8 of treatment) effects in Caucasian males. Beraprost sodium hemodynamic effects and potential benefits in patients with cardiovascular disease should be explored further.

Open trial of intravenous tissue plasminogen activator in acute carotid territory stroke. Correlations of outcome with clinical and radiological data.

BACKGROUND AND PURPOSE: Pilot studies using early thrombolytic therapy in stroke have suggested that recombinant tissue plasminogen activator (rTPA) might be effective. While large, double-blind, randomized studies are needed, open trials could generate hypotheses concerning (1) the clinical correlations of outcome, (2) the significance of CT scan data during the first week, and (3) the use of adjunctive therapies. METHODS: We performed an open trial of intravenous rTPA on patients referred to our emergency service with all types of ischemic stroke in the carotid territory. All patients between 20 and 81 years hospitalized during 1994 with completed stroke in the internal carotid artery territory and a baseline Scandinavian Stroke Scale score lower than 48, even with severe disturbances of consciousness, were included. The inclusion time was within 7 hours after stroke onset. A 0.8-mg/kg dose of rTPA was infused for 90 minutes. Intravenous heparin was given either immediately at efficient dosage or after 24 hours. Mannitol was used in patients with severe presentation. The Scandinavian Stroke Scale evaluation was done at baseline, 3 hours, and 1, 7, 30, and 90 days. The CT scan was performed before the treatment and at days 1 (24 +/- 6 hours) and 7. RESULTS: Forty-three consecutive patients met the criteria of the protocol. The mean age at inclusion was 65 +/- 10.4 years, and the mean interval to treatment was 232 +/- 79 minutes. At day 90, 25 patients (58.1%) exhibited a complete regression of symptoms, and 3 had moderate neurological sequelae. Thirteen patients had severe neurological sequelae, 11 with infarcts and 2 with secondary parenchymal hematomas. Two patients died (4.6%), 1 with hematoma. The overall hematoma rate was 6.9%. Excellent outcome at day 90 was significantly correlated with major neurological improvement at day 1. Intravenous immediate heparin versus delayed heparin after 24 hours improved the ischemic outcome but not the overall outcome. Reinfarction syndromes after major neurological improvement, likely to be rethrombosis syndromes, were observed in 3 patients (6.9%). For the day 1 CT scan, poor outcome was associated with the presence of structured and homogeneous hypodensities likely to represent classic infarcts, as confirmed by day 7 CT scan. Conversely, total recovery was significantly associated with the absence of any image or with unstructured hypodensities, a particular type of image characterized by its heterogeneous darkness and often polylobar shape. This type of image disappeared at day 7 in 17.6% of the cases and is likely to represent reperfusion images and/or incomplete ischemic damage. CONCLUSIONS: The results obtained in this open, small study suggest safety and effectiveness of rTPA thrombolysis at the dose of 0.8 mg/kg within 7 hours in acute strokes of the carotid territory, including highly serious baseline neurological presentations, until age 81 years and under special therapeutic conditions. Complete recovery is significantly associated with major neurological improvement during the first 24 hours and the presence of a particular type of image at day 1 CT scan characterized by an unstructured hypodensity, often polylobar and heterogeneous, which is likely to correspond to reperfusion images.

[Diagnosis of venous thrombosis and/or pulmonary embolism by determination of d-dimers using ELISA. Review based on a study of 80 consecutive patients hospitalized in an emergency unit]. / Le diagnostic de la thrombose veineuse et/ou de l'embolie pulmonaire par le dosage des D-Dimères ELISA. Mise au point à partir d'une étude portant sur 80 patients consécutifs hospitalisés dans un service d'urgence médicale.

The sensitivity and specificity of an ELISA method (Fibrinostika Fbdp Organon Teknika) for assay of D-dimers in the diagnosis of deep vein thrombosis and/or pulmonary embolism was studied in 80 consecutive patients seen at an emergency unit. Fifty-six of the patients presented clinical signs of deep vein thrombosis. Diagnosis was confirmed in 26 of the 56 patients with a D-dimer level above 370 ng/ml (sensitivity 92.3%) and 370 ng/ml for 13 of 30 patients with a negative venous ultrasound Doppler examination (specificity 43.3%). The positive predictive value was 58.5% and the negative predictive value was 87%. There was a significant difference in the level of D-dimers between distal and proximal deep vein thrombosis. In 40 cases with suspected pulmonary embolis, either alone or with suspected deep vein thrombosis, diagnosis was made in only 4 of 9 with a highly or intermediately probable ventilation/perfusion scan. D-dimer level was always above 3,000 ng/ml. Coupling the ELISA dimer test with noninvasive explorations improves negative predictive value but can also avoid invasive explorations (venography, pulmonary angiography) in certain patients. A D-dimer test as sensitive as the ELISA test and as rapid as the latex test remains to be described.

Quantitative immunochemistry of endothelial cells in cutaneous tissue.

In vivo endothelial cell exploration in human pathology has been limited by the lack of a suitable procedure for quantification of endothelial molecule expression. The objective of the present study was the development of a precise, simple and rapid image analysis method to quantify dermis endothelial cells and associated molecules. Cutaneous tissue sections were labelled by immunoperoxidase procedure using a monoclonal anti-von Willebrand factor (vWF) antibody, which identifies endothelial cells. The image analysis programme was tested to quantify final reaction deposit (DAB) with reference to different anti-vWF antibody concentrations. The entire biopsy section was acquired, field by field. Analysis was restricted to three dermis zones geodesically defined from epidermis. Optical density and area measurements were performed in whole area and in positive areas. This work demonstrated the feasibility of endothelial cell study assisted by image analysis. Surface labelled by anti-vWF antibody at saturating concentration may be considered as an endothelial reference surface, and thus may be useful for future quantification of other endothelial molecules.

Molecular study of Glanzmann thrombasthenia in 3 patients issued from 2 different families.

In an effort to further understand Glanzmann thrombasthenia (GT) 3 patients from 2 different families were studied. After biochemical and immunological analysis these patients were classified as type I. We observed in the first family a new restriction site for Stu I in exon II of the glycoprotein (GP) IIIa gene caused by a homozygous nonsense mutation: 62 Arg to stop codon. The parents were heterozygotes for this mutation. We found in the second family a previously described nonsense mutation: 584 Arg to stop codon in exon 17 of the GPIIb gene. The father and his two affected sons were heterozygous for this genetic defect. This mutation 62 Arg to stop codon is a new description of a genetic defect associated with GT. Furthermore, the discovery of the same mutation in 3 affected families from different ethnic groups raises the possibility of either a hot spot mutation in the CG dinucleotide region of GPIIb gene, or an ancient mutant allele present in diffuse populations at a relatively high frequency.