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Biomedical subjects

J Y Borg

Publications and source records attributed to J Y Borg.

At least 19 recordsLinked to original sources
PubMed2004

Thrombophilia and fetal growth restriction.

OBJECTIVE: Genetic thrombophilia may represent a new risk factor for obstetrical complications. The aim of the study was to determine which subgroups may be associated with genetic thrombophilia for small for gestational age infants (SGA). METHODS: A case-control study was performed in three different maternity wards in Normandy. Cases (n=203) were women who had pregnancies complicated by unexplained SGA infants defined as a birth weight below the 3rd centile and control subjects (n=203) were women who had infants with birth weight > or =10th centile. Patients were tested in the immediate postpartum period and 2 months later for factor V Leiden mutation, and prothrombin 20210A mutation. Frequencies of these mutations were observed in different subgroups of SGA infants depending on pregnancy or neonatal outcomes usually associated with intrauterine growth restriction (IUGR), and were then compared with the overall prevalence for these mutations detected in the control group. RESULTS: Prevalences for factor V Leiden mutation (or=2.58; 95% confidence interval: 0.83-8.04), prothrombin 20210A mutation (or=2.03; 95% confidence interval: 0.51-8.01), were comparable between cases and controls (4.9% versus 1.9% and 2.9% versus 1.4%, respectively). Frequencies for these two polymorphisms significantly increased in subgroups of SGA infants with a normal Pourcelot index (13/133 versus 7/203; P=0.04), a gestational age > or =37 weeks of gestation (15/143 versus 7/203; P=0.01), a vaginal delivery (11/117 versus 7/203; P=0.04), a birth weight > or =2000 g (12/121 versus 7/203; P=0.03), no admission to paediatric ward (11/116 versus 7/203; P=0.01), a low Ponderal index <2.5(e) centile (6/45 versus 7/203; P=0.04), and normal head circumference >10th centile (7/53 versus 7/203; P=0.01) in comparison with the control group. CONCLUSIONS: An association was found between polymorphisms for factor V Leiden and prothrombin, and asymmetrical intrauterine growth restriction with immediate favourable neonatal outcomes.

Adult↗
PubMed2004

Analysis of biological phenotypes from 42 patients with inherited factor VII deficiency: can biological tests predict the bleeding risk?

BACKGROUND AND OBJECTIVES: Inherited factor VII (FVII) deficiency is a rare bleeding disorder characterized by a poor relationship between reported FVII clotting activity (FVII:C) and bleeding tendency. Our study was aimed at defining biological parameters that are possibly predictive for bleeding risk in this condition. DESIGN AND METHODS: Forty-two FVII-deficient patients (FVII:C <30%) were classified into two opposite clinical groups defined as severe and non-or-mild bleeders. For each patient, plasma samples were collected and then investigated for FVII:C (using a sensitive method and human recombinant thromboplastin as the reagent), FVII antigen, activated FVII coagulant activity (FVIIa:C) and the free-form of tissue factor pathway inhibitor. RESULTS: None of these tests could be used as highly accurate predictors of bleeding. Nevertheless, both FVII:C and FVIIa:C differed significantly between the two clinical groups. Using ROC-curve analysis, two critical values of 8% and 3mIU/mL for FVII:C and FVIIa:C, respectively, could be proposed to discriminate between severe bleeders and non-or-mild bleeders. INTERPRETATION AND CONCLUSIONS: A highly accurate diagnostic test for predicting bleeding tendency in inherited FVII deficiency still eludes definition, highlighting the fact that factors other than FVII itself interfere with the expression of bleeding phenotypes in this condition. Nevertheless, potential critical values using sensitive FVII:C and FVIIa:C methods may be useful in clinical laboratories for FVII-deficient patients. Those patients with FVII:C levels higher than 8% FVII:C or FVIIa:C higher than 3 mIU/mL, with no other hemostatic defect, seem to have a minimal risk of severe bleeding. Extended clinical studies are needed to support these findings.

Adolescent↗
PubMed2002

Antiphospholipid antibodies in the acute phase of cerebral ischaemia in young adults: a descriptive study of 139 patients.

A total of 139 young stroke patients were consecutively examined and tested for antiphospholipid antibodies (APLA) to evaluate the role of these antibodies in cerebral ischaemia before the age of 45. APLA were found in 28.8% of patients. Two factors, hypertriglyceridaemia and alcohol abuse, were significantly more frequent in patients with a positive APLA test. The demographic characteristics, other risk factors, history of prior thrombotic events and distribution of aetiopathogenic types of cerebral ischaemia were not different in patients with or without APLA. Laboratory assays for APLA were highly positive for only two patients, who both had autoimmune diseases. These results suggest that with the exception of a clinical context of antiphospholipid syndrome or other autoimmune diseases, the usefulness of this diagnostic tool in the management of cerebral ischaemia remains limited.

Acute Disease↗
PubMed2001

Frequency of protein Z deficiency in patients with ischaemic stroke.

Prothrombotic phenotype has been described in protein-Z deficient mice, but the thrombotic risk associated with protein Z deficiency in human beings is unknown. We saw a protein Z plasma concentration deficiency of about 20% in 169 patients, from two hospitals, who had ischaemic stroke, whereas the frequency in 88 controls was about 5%. We saw no increase in the frequency of protein Z deficiency in 56 patients with venous thrombophilia. However, why protein Z deficiency was only observed in arterial thrombosis remains unknown.

Adult↗
PubMed2001

Molecular analysis of the fibrinogen gene cluster in 16 patients with congenital afibrinogenemia: novel truncating mutations in the FGA and FGG genes.

Congenital afibrinogenemia is an autosomal recessive disorder characterized by the complete absence of detectable fibrinogen. We previously identified the first causative mutations for this disease in a non-consanguineous Swiss family. These were homozygous deletions of approximately 11 kb of the fibrinogen alpha chain gene (FGA). Our subsequent study revealed that the majority of cases were attributable to truncating mutations in FGA, with the most common mutation affecting the donor splice site in FGA intron 4 (IVS4+1 G-->T). Here, we report 13 further unrelated patients with mutations in FGA, confirming the relative importance of this gene compared with FGG and FGB in the molecular aetiology of afibrinogenemia. Three other patients were homozygous for mutations in FGG. Eight novel mutations were identified: five in FGA and three in FGG. Sufficient mutation data is now available to permit an effective strategy for the genetic diagnosis of congenital afibrinogenemia.

Afibrinogenemia↗
PubMed2001

[Acquired hemophilia: current diagnostic and therapeutic approaches].

PURPOSE: Acquired haemophilia is a rare disease, occurring most frequently in elderly patients, caused by the development of autoantibodies against factor VIII. CURRENT KNOWLEDGE AND KEY POINTS: The disease is characterised by spontaneous haemorrhagic complications which can be fatal in 15-20% of the patients. However spontaneous remission is possible and in fact natural evolution and aetiology are still partly unknown. Acquired haemophilia may arise in association with auto-immune diseases, lymphoproliferative malignancy, pregnancy and also as a drug reaction. The aims of the treatment are first to treat the bleeding which is the most common cause of morbidity and mortality, and second to eliminate the inhibitor by immunosuppression. However no consensus exists for these two parts of the treatment. Bleeding may be controlled by prothrombin complex concentrates, recombinant factor VIIa or porcine factor VIII. The inhibitor is abolished in up 70% of patients using prednisone and cyclophosphamide. Other combinations of prednisone with azathioprine or with cyclophosphamide and vincristine or the use of high-dose immunoglobulin or double-filtration plasmapheresis have also proven effective in some patients. FUTURE AND PROJECTS: The rare occurrence of the disease, the associated with various diseases, and lack of consensus about treatment, require multicentric prospective studies.

Aged↗
PubMed2001

Venous thromboembolism during pregnancy: a retrospective study of enoxaparin safety in 624 pregnancies.

OBJECTIVE: To assess the maternal, fetal and neonatal safety of enoxaparin in pregnant women who require antithrombotic therapy. DESIGN: Retrospective analysis of case notes of women who received enoxaparin during pregnancy, irrespective of dose, duration and reason for treatment. SETTING: Fifty-five French perinatal centres. SAMPLE: Data from 624 pregnancies in 604 women between 1988 and 1997. The incidence of previous thromboembolism was 29.8%, known thrombophilia 15.2%. METHODS: Indication, regimen of enoxaparin and outcome measures were reported for each pregnancy. Information was obtained from case records, validated by research staff and analysed by an independent scientific committee. MAIN OUTCOME MEASURES: Incidence, seriousness and causality of maternal, fetal and neonatal adverse events, pregnancy outcome, and incidence of venous thromboembolism. RESULTS: Enoxaparin was administered for treatment of an acute episode in 49 cases and for thromboprophylaxis in 574 cases. Serious maternal haemorrhage occurred in 11 cases during pregnancy (1.8%), one being reasonably related to enoxaparin, and in nine cases at delivery (1.4%), all unrelated to enoxaparin. Maternal thrombocytopenia was reported in 10 cases (1.6%). two being serious but unrelated to enoxaparin. Eight pregnancies ended in stillbirth (1.1%). Among the 693 live births, 17 major congenital abnormalities (2.5%) and 10 serious neonatal haemorrhages (1.4%) were reported. None of the fetal or neonatal adverse events was related to enoxaparin. Eight venous thromboembolic events (1.3%) were reported. CONCLUSIONS: The incidence of adverse events reported could be explained by the high risk profile of the study population. Overall, this retrospective study suggests enoxaparin is well tolerated during pregnancy.

Adult↗
PubMed2001

Prothrombotic inherited abnormalities other than factor V Leiden mutation do not play a role in venous thrombosis in inflammatory bowel disease.

OBJECTIVES: Because the incidence of thromboembolism is increased in patients with inflammatory bowel disease, we attempted to assess the role of prothrombotic inherited coagulation abnormalities in the development of thrombosis. METHODS: Four populations were compared: 15 patients with inflammatory bowel disease and a previous venous thrombosis, 58 control patients with inflammatory bowel disease but without thrombosis, 110 patients without inflammatory bowel disease but with previous deep venous thrombosis, and 84 healthy subjects. Inherited and acquired risk factors of venous thrombosis, e.g., factor V Leiden and prothrombin 20210A mutations, C677T methylenetetrahydrofolate reductase polymorphism, a polymorphism located in exon 13 of factor V gene, inflammatory and hypercoagulability markers were studied in each population. RESULTS: In the study, 14.3% of thrombotic patients with inflammatory bowel disease had factor V Leiden mutation versus 0% of control patients with inflammatory bowel disease (p = 0.04), 15.5% of thrombotic patients without inflammatory bowel disease (NS) and 3.6% of the healthy controls. A total of 14% of thrombotic patients with inflammatory bowel disease and 11.8% of thrombotic patients without inflammatory bowel disease carried prothrombin 20210A mutation, compared to 1.7% of control patients with inflammatory bowel disease; however, the difference was just below significance. Other inherited coagulation abnormalities were not statistically significantly different among the four populations. CONCLUSIONS: Our study confirms that factor V Leiden mutation increases the risk for thrombotic events but is not more frequent in patients with inflammatory bowel disease. Our results do not support the role of other thrombotic risk factors.

Adult↗
PubMed2001

Quantification of lupus anticoagulants in clinical samples using anti-beta2GP1 and anti-prothrombin monoclonal antibodies.

Quantification of lupus anticoagulant (LA) in clinical samples is hampered by the lack of a suitable standard of activity. We evaluated the use of mAbs displaying LA activity for this purpose. As most patient samples contain both beta2Glycoprotein I (beta2GP1) and prothrombin dependent LA, a combination of two mAbs, one of each specificity, was added to normal plasma in a concentration from 0 to 60 microg/ml. Eight assay systems using different reagents and instruments were used. The calibration curves were linear for all but one, with marked differences between the responsiveness to each mAb. A panel of plasmas from 69 patients with persistent LA diagnosed using the SSC-ISTH criteria was tested. An antiphospholipid syndrome (APS) was present in 40, whereas 29 were asymptomatic. LA activities of individual plasmas varied between assays (p < 10(-4)), but homogeneous subgroups were identified. In a majority of samples, LA activity displayed a prothrombin-dependent profile, with a variable contribution of beta2GP1-dependent activity. The latter was associated to beta2GP1 antibodies detected by solid-phase immunoassay. By using 3 dilute Russell viper venom time assays, higher LA titers were found in APS, compared to asymptomatic patients (p <0.05).

Adult↗
PubMed2000

[Inherited thrombophilia and pregnancy].

Inherited thrombophilia include deficiences of antithrombin III, protein C and protein S, and the factor V Leiden mutation, the prothrombin gene variant, and homozygosity for the thermolabile variant of methylenetetrahydrofolate reductase (MTHFR). The incidence of thromboembolism events during pregnancy and postpartum period among women with thrombophilia is not well known and depends on the prethrombotic state resulting from the interaction of the underlying thrombophilic defect(s), history of congenital thrombophilia, and additional risk factors. In that way, many patients with congenital thrombophilia will require antenatal thromboprophylaxis, the timing of which will depend on the patient's history and thrombophilic disorders. Low molecular weight heparin appeared to be a safe alternative to unfractionated heparin for both the fetus and the mother during the pregnancy. Case-control studies have recently demonstrated that serious obstetrical complications i. e severe preeclampsia, abruptio placentae, intrauterine growth restriction, and stillbirth were frequently associated with inherited thrombophilia. Controlled trials are now urgently needed to determine the possible potential benefits of anticoagulant therapy in pregnancy outcome. Finally, there is no evidence to support routine screening for congenital thrombophilia during pregnancy.

Antithrombin III Deficiency↗
PubMed1999

Small for gestational age infant in association with maternal prothrombin gene variant (nt 20210A).

Most of disproportionate infants born small for gestational age (SGA) have an history of placental dysfunction with no explained cause. We report a case of an unexplained SGA infant with placental infarctions and thrombosis. Maternal thrombophilic disorder tests revealed that the patient was heterozygous for the A20210 prothrombin gene variant a newly identified thrombotic risk factor. It may be suggest that prothrombin gene variant, as factor V Leiden, could be a genetic risk factor for placental insufficiency.

Adult↗
PubMed1999

Influence of three potential genetic risk factors for thrombosis in 43 families carrying the factor V Arg 506 to Gln mutation.

The factor V (FV) Arg 506 to Gln mutation is the most common abnormality observed in familial thrombophilia. Many studies have shown that its clinical expression differs among families and among carriers. Some thrombotic patients carry an additional genetic risk factor such as protein C, protein S or antithrombin deficiency. We sought to identify other genetic risk factors potentially favouring expression of the thrombotic phenotype in 370 members of 43 families with the FV Arg 506 to Gln mutation. We analysed three candidate polymorphisms in genes involved in the PC anticoagulant pathway, consisting of two polymorphic sites in the 5' non-transcribed region of the PC gene, -1654 C/T and -1641 A/G, with three known combinations (TA, CA and CG) that influence the protein C plasma level; one polymorphic site (4070 A/G) in exon 13 of the FV gene, which influences the plasma factor V concentration, and one polymorphic site (677 C/T) in the methylenetetrahydrofolate reductase gene, which is often associated with moderate hyperhomocysteinaemia. The distribution of these different polymorphisms was similar in patients with a history of thrombosis and those who remained asymptomatic, ruling out the possibility that each of these polymorphisms alone can play a role in the onset of thrombosis in carriers of the FV Arg 506 to Gln mutation.

Adolescent↗
PubMed1999

Decision analysis for use of platelet aggregation test, carbon 14-serotonin release assay, and heparin-platelet factor 4 enzyme-linked immunosorbent assay for diagnosis of heparin-induced thrombocytopenia.

The value of the platelet aggregation test, carbon 14-labeled serotonin release assay (SRA), and heparin-platelet factor 4 enzyme-linked immunosorbent assay (H-PF4 ELISA) for the diagnosis of heparin-induced thrombocytopenia was evaluated by studying blood samples from 100 patients with suspected heparin-induced thrombocytopenia, and categorized into 4 clinical groups: unlikely (n = 22), possible (34), probable (36), and definite (8) thrombocytopenia. Results of the platelet aggregation test were positive in 40 of 44 patients with probable or definite heparin-induced thrombocytopenia (sensitivity 91%) and in 5 of 22 unlikely to have heparin-induced thrombocytopenia (specificity 77%). The SRA exhibited sensitivity of 88% and negative predictive value of 81%, close to those values for the platelet aggregation test; specificity and positive predictive value were 100%. The sensitivity of the heparin-PF4 ELISA was 97%, with specificity 86%, and a positive correlation was recorded between the level of antibodies to H-PF4 and clinical score (P = 0.66). When ELISA was used with the platelet aggregation test or SRA, positive predictive value and specificity were 100% when both tests yielded positive results, and negative predictive value was 100% when both tests yielded negative results. A biologic flow chart was designed that presented a choice based on the results of the platelet aggregation test or SRA in association with ELISA, and enabled more accurate and specific identification of heparin-induced thrombocytopenia.

Carbon Radioisotopes↗
PubMed1997

Differences in specificity of heparin-dependent antibodies developed in heparin-induced thrombocytopenia and consequences on cross-reactivity with danaparoid sodium.

Heparin-induced thrombocytopenia (HIT) is frequently associated with antibodies (Abs) to heparin-PF4 complexes (H-PF4). In order to investigate whether there are variations in specificity of Abs, we studied 63 samples from patients with suspected HIT. Two groups of samples were separated after comparing their reactivity against H-PF4 or recombinant PF4 (r-PF4) using ELISA. In group Ab1 (n = 46), Abs only or mainly bound to H-PF4 complexes and thus most of the epitopes recognized probably involved both heparin and PF4. In group Ab2 (n = 17), Abs exhibited similar reactivity to r-PF4 and H-PF4, and the antigens recognized were possibly neoepitopes mainly expressed by modified PF4 and by H-PF4 complexes. Platelet activation tests were positive with 56 samples containing high titres of Abs to H-PF4. Most samples (n = 59) contained IgG antibodies, often associated with IgA antibodies which were more frequently found in group Ab2, and/or IgM. With unfractionated heparin treatment, HIT was associated with Ab1 or Ab2 antibodies, whereas only Ab1 antibodies were detected after low-molecular-weight heparin (LMWH). Furthermore, cross-reactivity with danaparoid sodium was present only in group Ab1 and mainly involved LMWH-treated patients.

Adult↗