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PubMed2002

Anti-beta2-glycoprotein I and anti-prothrombin antibodies in antiphospholipid-negative patients with thrombosis: a case control study.

We performed a case-control study to assess whether anti-beta2-glycoprotein I and anti-prothrombin antibodies are independent risk factors of thrombosis. Cases were 79 patients with arterial and/or venous thrombosis without lupus anticoagulants, anticardiolipin antibodies and systemic lupus erythematosus; controls were 85 normal subjects. The prevalences and titers of IgG and IgM anti-beta2-glycoprotein I and anti-prothrombin antibodies were similar in both groups. Cases were analyzed with respect to the arterial or venous type of thrombosis and to the presence of congenital or acquired risk factors for thrombosis: no statistically significant relationships with the presence of anti-beta2-glycoprotein I and anti-prothrombin antibodies were found. Our data indicate that anti-beta2-glycoprotein I and anti-prothrombin antibodies are not risk factors for thrombosis independent of lupus anticoagulants and anticardiolipin antibodies. Their measurement, therefore, is not warranted in the laboratory screening of patients with arterial and/or venous thrombosis.

Adolescent↗
PubMed2003

Prothrombin G20210A mutation and oral contraceptive use increase upper-extremity deep vein thrombotic risk.

The role played by a hypercoagulable state, either inherited or acquired, in the pathogenesis of upper-extremity deep vein thrombosis (UEDVT) remains a question of debate. We performed a case-control study including 79 patients with a first objectively confirmed episode of UEDVT, 31 secondary and 48 primary, and 165 healthy controls. Nine patients (11.4%) with UEDVT were carriers of the prothrombin G20210A mutation vs. six (3.7%) in controls; P = 0.025, OR: 3.39 (95% CI 1.16 to 9.88). No statistical difference was observed between cases and controls for the factor V Leiden mutation, AT, protein C or protein S deficiency and anticardiolipin antibodies (ACAs). Thirteen (35.1%) UEDVT patients were oral contraceptive (OC) users vs. 12 (16%) controls; P = 0.020, OR: 2.89 (95% CI 1.16-7.21). When secondary UEDVT patients were compared with controls, no differences were observed in any of the risk factors analysed. On the other hand, when primary UEDVT was considered, six (12.5%) patients were carriers of the prothrombin G20210A mutation vs. six (3.7%) controls; P = 0.031, OR: 3.76 (95% CI 1.15-12.26). Regarding ACAs, a borderline statistical significance was observed when primary UEDVT was compared with controls, P = 0.048; OR: 4.88 (95% CI 1.05-22.61). In primary UEDVT, 52% of the fertile women were OC users vs. 16% of controls; P = 0.001, OR: 5.78 (95% CI 2.13-15.67). When the interaction of both factors, i.e. prothrombin G20210A mutation and OC intake, were considered, the risk increased markedly, indicating a synergistic effect as observed with other thrombotic locations. In patients with primary UEDVT screening for antithrombin, protein C and protein S deficiency and APC resistance would not be justified, although it might be reasonable to determine the carrier status of the prothrombin G20210A mutation only in OC users.

Adolescent↗
PubMed2004

Factor V leiden and prothrombin gene mutation: risk factors for osteonecrosis of the femoral head in adults.

The purpose of the current study was to determine whether factor V Leiden and the prothrombin 20210A gene mutation are risk factors for osteonecrosis of the femoral head in different etiologic groups of osteonecrosis in adults and whether patients with idiopathic osteonecrosis of the femoral head have a higher frequency of thromboembolic events compared with the general population. We investigated 63 adult patients with nontraumatic osteonecrosis of the femoral head for etiologic factors, such as corticosteroid medication and alcohol abuse, and the occurrence of factor V Leiden and the prothrombin 20210A gene mutation. In 35 patients, the disease was considered idiopathic and 10 of these patients (29%) had factor V Leiden or the prothrombin 20210A gene mutation or both. Mutations in factor V or the prothrombin 20210A gene were significantly more frequent in patients with idiopathic osteonecrosis than in a population of healthy control subjects (odds ratio, 2.7; 95% confidence interval range, 1.2-5.8) and in patients with osteonecrosis caused by corticosteroid medication or alcohol abuse (odds ratio, 10.8; 95% confidence interval range, 1.4-84). 36% of patients with a gene mutation had had a thromboembolic event compared with 8% of patients without a gene mutation. Thromboembolic events were more common among patients with idiopathic osteonecrosis (17%) compared with the general population (4%) and with patients with osteonecrosis caused by corticosteroid medication or alcohol abuse (7%).

Factor V↗
PubMed2004

G20210A prothrombin gene variant and clinical outcome in patients with a first acute coronary syndrome.

BACKGROUND AND OBJECTIVES: The prognostic value of the G20210A prothrombin gene polymorphism in patients with a first acute coronary syndrome has not been previously assessed. We conducted a prospective study to investigate this issue. DESIGN AND METHODS: Genotyping at the 20210 prothrombin gene locus was performed in 162 patients with a first episode of myocardial infarction (MI) or unstable angina (UA) occurring before 65 years of age. Patients were stratified according to cardiovascular risk factors and to treatment strategy. The subsequent two-year relative risk (RR) of adverse events (death, MI and UA) was adjusted for possible confounders and analyzed according to genotype, risk factor category, and treatment allocation. RESULTS: In the entire study population, the prothrombin variant did not significantly increase the two-year risk of events: the adjusted RR for GA vs GG carriers was 1.82 (95% CI 0.68-4.89). However, in the absence of traditional cardiovascular risk factors the risk of events was consistently higher: among the 46 patients without hypertension, diabetes and hypercholesterolemia, GA vs GG carriership was associated with an adjusted RR at two years of 5.64 (95% CI 1.07-29.84). The gene variant also enhanced the risk of events among the 98 patients who did not undergo myocardial revascularization procedures (RR for GA vs GG: 2.89, 95% CI 1.04-8.00), but not among those who did. INTERPRETATION AND CONCLUSIONS: The present prospective study suggests that heterozygosity for the G20210A prothrombin polymorphism adversely affects prognosis after a first acute coronary syndrome in the subgroup of patients without metabolic risk factors and in those not treated by revascularization procedures.

3' Untranslated Regions↗
PubMedDate not supplied

Low frequency of factor V Leiden and prothrombin G20210A mutations in patients with hepatic venous outflow tract obstruction in northern India: a case-control study.

BACKGROUND: Factor V Leiden (FVL) and prothrombin gene (G20210A) mutations are known to be associated with venous thromboembolism. Several studies have shown an association of these mutations with hepatic venous outflow tract obstruction (HVOTO). We studied the prevalence of these mutations among patients with HVOTO in northern India in comparison with healthy population. METHODS: Genomic DNA from patients with HVOTO and healthy controls was analyzed for the presence of FVL and prothrombin gene G20210A mutations, using PCR and restriction-fragment length polymorphism. RESULTS: Fifty-nine patients with HVOTO (age 5-69 years, median 27; 39 male) and 49 unrelated healthy controls from the same geographic region were studied. Of the 59 patients, 19 had a block in the hepatic vein, 7 in inferior vena cava, and 33 had mixed block. Presentation was with acute thrombosis in 9 patients and with long-standing obstruction in 50 patients. Among 49 controls, heterozygous and homozygous FVL mutations were observed in 2 and 0 subjects, respectively, with an allele frequency of 2% (2 of 98). In comparison, among 59 patients with HVOTO, four had heterozygous and none had homozygous FVL mutation, with an allele frequency of 3.4% (p=ns versus controls). The G20210A prothrombin gene mutation was not found in any of the patients or controls. CONCLUSION: FVL and prothrombin G20210A mutations appear to have no role in the pathogenesis of HVOTO in our patients with Budd-Chiari syndrome, consisting largely of those with long-standing obstruction of the inferior vena cava.

Adolescent↗
PubMed2006

Prothrombin gene 20209 C >T along with the first description of a homozygous polymorphism at the 3' downstream region +4 C >T in the Turkish population.

Mutation screening studies related with thrombosis revealed that prothrombin 20210A allele of the prothrombin gene leads to an increase in plasma prothrombin levels. The G20210A mutation screening has become a routine analysis in patients with thrombosis. For the detection of the mutation, several molecular techniques have been defined. Real-time polymerase chain reaction is an easy and feasible way to monitor this mutation according to the melting point analysis. Here we report a different pattern in the LightCycler melting point analysis of 2 patients with thrombosis. DNA sequencing of the prothrombin gene showed that these patients with an atypical melting point profile carry a 20209 C >T mutation along with a novel homozygous polymorphism at the 3' downstream region, +4 C >T.

Adolescent↗
PubMedDate not supplied

Factor V Leiden and prothrombin gene G20210A mutations are uncommon in portal vein thrombosis in India.

BACKGROUND: Extra-hepatic portal vein obstruction due to portal vein thrombosis (PVT) is an important cause of portal hypertension in several regions including India. The cause of thrombosis in these patients remains unclear. We studied the frequency of mutations in genes for coagulation factors V and II (prothrombin) in 61 Indian patients with PVT and 49 healthy control subjects. METHODS: The presence of factor V Leiden mutation and of G20210A prothrombin gene mutation was determined using polymerase chain reaction followed by restriction fragment length polymorphism. Chi-squared test was used to compare patients and controls. RESULTS: Of the 61 patients (median age 11 years; 47 male) studied, 49 were children. One of 61 (1.6%) patients with PVT was heterozygous for factor V Leiden mutation and none had the G20210 prothrombin gene mutation. The frequencies of these mutations were not different from those in control subjects (2/49 and 0/46, respectively). CONCLUSION: Factor V Leiden and G20210 prothrombin gene mutations are infrequent in Indian patients with PVT. Thus, these mutations are unlikely to be responsible for PVT in the Indian population.

Adolescent↗
PubMed1976

Human plasma lipoproteins as accelerators of prothrombin activation.

The activation rate of bovine prothrombin by Factor Xa and Ca2+ has long been known to be greatly enhanced by addition of phospholipid. Upon substitution of human plasma lipoproteins for phospholipid (cephalin) in this activation system, only very low density lipoprotein enhances prothrombin activation. Low density lipoprotein and high density lipoprotein have no stimulatory effect on prothrombin activation. On the other hand, the sonicated lipid extracts from very low, low, and high density lipoproteins all can substitute for phospholipid in potentiating prothrombin activation. The efficiency of each lipid extract, in this regard, depends upon its source of extraction, and is greatest for the lipid extract of very low density lipoprotein.

Calcium↗
PubMed1991

Determination of human prothrombin activation fragment 1 + 2 in plasma with an antibody against a synthetic peptide.

The present investigation describes a novel approach to prepare a specific antibody against prothrombin activation fragment 1 + 2 (F 1 + 2). The antibody discriminates between native prothrombin and F 1 + 2 in plasma. A synthetic peptide from the negatively charged region of F 1 + 2, which becomes the carboxy-terminal sequence after cleavage of prothrombin by factor Xa, was used for immunization of rabbits. Obtained antiserum was immunopurified and an enzyme-linked immunosorbent assay (ELISA) was constructed for determination of F 1 + 2. The test system follows the sandwich principle and uses two different antibodies directed against F 1 + 2 and prothrombin, respectively. The ELISA was calibrated with purified F 1 + 2 added to F 1 + 2-poor plasma. The lower limit of sensitivity of the assay was 0.02 nmol/l. Coefficients of variation of 6.9 to 10.4% (intraassay) and 6.7 to 11% (interassay) were found for F 1 + 2 concentrations between 0.08 and 4.9 nmol/l. A reference range from 0.32 to 1.2 nmol/l was calculated from 95 healthy donors (mean value +/- SD: 0.67 +/- 0.19 nmol/l). In patients with deep vein thrombosis (n = 7) confirmed by phlebography and in patients with pulmonary embolism (n = 8) confirmed by lung scan, F 1 + 2 levels were found up to 1.5 to 9.5 nmol/l. In plasma samples of patients under oral anticoagulant therapy in the stable state F 1 + 2 concentrations were found to be in the range of 0.08 to 0.5 nmol/l.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1988

Measurement of prothrombin mRNA during gestation and early neonatal development.

Prothrombin levels in the fetal and newborn lamb follow a gestational age-related pattern of development. The changes in activity are reflected by similar changes in prothrombin antigen concentration. Our investigations indicate that these changes in prothrombin antigen and activity levels are paralleled by changes in the levels of prothrombin messenger RNA present in liver samples from fetuses of various gestational ages.

Animals↗
PubMed1987

Concurrent lupus anticoagulants and prothrombin deficiency due to phenytoin use.

A man with lupus anticoagulant and a prothrombin deficiency was studied before and after cessation of treatment with phenytoin. Multiple abnormal laboratory values of the following partially or completely resolved after the patient's therapy was discontinued: tissue thromboplastin inhibition ratio, prothrombin time, activated partial thromboplastin time, anticardiolipin antibodies, and quantitative measures and abnormal pattern on crossed immunoelectrophoresis of prothrombin. This patient represented an example of a concurrent drug-induced prothrombin deficiency and a lupus anticoagulant.

Adult↗
PubMedDate not supplied

[Formation of a heparin-prothrombin complex].

Formation of complex between heparin and prothrombin was shown using a spectral method. A method is developed for production of active complex heparin-prothrombin with the ratio of components as 1 : 6. The heparin-prothrombin complex obtained exhibited the anticoagulant and antipolymerization properties as well as the nonenzymatic fibrinolytic effect on instabilized fibrin both in absence and in presence of such blocking agents of enzymatic fibrinolysis as epsilon-aminocapronic acid and soybean inhibitor of trypsin. The increase in the anticoagulant and nonenzymatic fibrinolytic properties of blood occurred after intravenous administration of the complex into animals. The heparin-prothrombin complex acted in circulation within 1.5--2 hrs.

Animals↗
PubMed1979

The effect of prothrombin fragment 2 on the inhibition of thrombin by antithrombin III.

The effect of prothrombin fragment 2 on the inhibition of thrombin by antithrombin III has been studied. Fragment 2 was found to slow the rate of inhibition of thrombin by antithrombin III about 3-fold. The effect of prothrombin fragment 2 on antithrombin III inhibition was examined by comparing its action in the presence of either thrombin or meizothrombin (des fragment 1). The second order rate constants for antithrombin III inhibition of thrombin with saturating fragment 2 and antithrombin III inhibition of meizothrombin (des fragment 1) were the same. Prothrombin fragment 2 had no effect on either antithrombin III inhibition of meizothrombin (des fragment 1) or Factor Xa. The effect of the fragment on the reaction mechanism of thrombin inhibition was evaluated to see if the fragment altered binding of antithrombin III to thrombin or inhibited the formation of the covalent complex. The fragment was found to have no inhibitory effect on the rate of covalent complex formation, indicating that the protective effect of the fragment is by inhibiting binding of antithrombin III to thrombin. These data suggest that prothrombin fragment 2 may be an important factor in controlling the localization of clot formation by regulating the interaction between thrombin and antithrombin III.

Animals↗
PubMed1971

The "therapeutic range" of the one-stage prothrombin time in the control of anticoagulant therapy: the effect of different thromboplastin preparations.

Commercially available thromboplastin reagents and two human brain preparations have been compared using the one-stage prothrombin time and plasma samples from patients receiving long-term oral anticoagulant therapy. Considerable variation is noted between various thromboplastins using the same plasma sample. The commercially available thromboplastins give shorter prothrombin times than do human brain preparations. With the latter, the "therapeutic range" is represented by a prothrombin time of about 1.8 to 3.0 times the normal control value, whereas with commercial preparations the "therapeutic range" is about 1.25 to 1.75 times normal. The implications of these observations are discussed; the desirability of standardization of the one-stage prothrombin time is emphasized.

Anticoagulants↗
PubMed1976

The "echis carinatus venom" prothrombin assay in coumarin treated patients. A comparison with one-stage and immunological assays.

Prothrombin (factor II) was assayed in a group of coumarin treated patients using the Echis carinatus venom as thromboplastin. The levels obtained were comparable to those observed using the classical one-stage method. A good correlation was in fact observed between the two methods. The levels observed by the Echis carinatus method were definitely lower than those obtained using two immunological methods indicating that Echis carinatus venom activated, in our system, only normal prothrombin. However, even the levels obtained immunologically were slightly decreased, regardless of the method used, as compared to pooled normal plasma. In congenital prothrombin deficiency (homozygotes and heterozygotes) the level obtained by the Echis carinatus method was comparable to that observed by the one-stage method. On the contrary, in a congenital dysprothrombinemia (prothrombin Padua) a normal level was observed whereas the one-stage and two-stage methods yielded constantly levels of about 50% of normal.

Animals↗
PubMed1984

Factor IX and prothrombin in amniotic fluid and fetal plasma: constraints on prenatal diagnosis of hemophilia B and evidence of proteolysis.

Potential limitations of prenatal diagnosis of hemophilia B, as compared to hemophilia A, include (1) occurrence of far more frequent defects with abnormal circulating antigen, (2) lower levels of factor IX in fetal plasma at 16 to 20 weeks gestation, and (3) the presence of factor IX antigen in amniotic fluid. In addition, proteolysis could occur, especially with amniotic fluid contamination of fetal plasma. A sensitive polyclonal immunoradiometric assay for factor IX antigen was used to characterize the range of levels in amniotic fluids and fetal plasma samples. To assess for altered forms, factor IX species were compared to those of a homologous clotting factor, prothrombin. Fourteen postmortem abortus blood samples from fetuses of 14 to 23 weeks gestation had factor IX antigen levels that averaged 5.1 U/dL and ranged from 1.7 to 15 U/dL. Amniotic fluid factor IX antigen averaged 2.9 U/dL, with a range from 1.4 to 8.5 U/dL in 19 separate amniocentesis samples. Thus, in a male fetus at risk of hemophilia B and with a low circulating level of gene product, mixture of fetal plasma with amniotic fluid could severely limit prenatal diagnosis, assuming that the amniotic fluid factor IX is of maternal origin. Despite rapid processing of amniotic fluid samples, the prothrombin was extensively cleaved, suggesting that it had been activated in vivo. On gel electrophoresis of amniotic fluid samples, however, factor IX was only minimally cleaved. In the postmortem fetal blood specimens, prothrombin was partially cleaved. On crossed-immunoelectrophoresis, fetal plasma prothrombin showed decreased migration in calcium, compared to EDTA, indicative of mature gamma-glutamyl carboxylation. The latter presumably resulted from fetal hepatic synthesis.

Amniotic Fluid↗
PubMed1984

The adsorption of prothrombin to phospholipid monolayers quantitated by ellipsometry.

We investigated by means of an automated ellipsometer the calcium-dependent binding of prothrombin from a buffer solution to monolayers of dioleoylphosphatidylserine (DOPS) and dioleoylphosphatidylcholine (DOPC) deposited on chromium slides. This technique allows direct measurements of bound and free protein concentrations and is not hampered by calcium-induced aggregation of vesicles. For pure DOPS a dominant class of binding sites exists with a dissociation constant, Kd = (6 +/- 2) X 10(-10) M (mean +/- S.D.) and maximal binding of prothrombin, gamma max = 0.26 +/- 0.03 micrograms/cm2. Incorporation of a small fraction of DOPC in the monolayer causes a large decrease in the binding affinity with a pronounced biphasic behavior of the binding curve. For monolayers consisting of 20% DOPS and 80% DOPC the binding curve becomes monophasic with Kd = (1.6 +/- 0.6) X 10(-7) M and gamma max = 0.22 +/- 0.03 micrograms/cm2. The procoagulant activity of the monolayers was tested by measuring the generation of thrombin after addition of prothrombin and activated coagulation factors X and V. The thrombin-generating capacity of monolayers and single-bilayer vesicles is comparable but is apparently diffusion limited in the monolayer system. The calcium-dependent formation of stacked multilayers according to the Blodgett technique appeared to be strongly influenced by the DOPS/DOPC ratio in the phospholipid monolayer. From these results it is concluded that for pure DOPS monolayers high-affinity prothrombin-phospholipid and phospholipid-phospholipid interactions exist which are radically disturbed when the monolayer contains more than 20-30% of DOPC.

Adsorption↗
PubMed1983

Albumin, fibrinogen, prothrombin and antithrombin III variations in blood, urines and liver in rat nephrotic syndrome (Heymann nephritis).

Albumin, fibrinogen, prothrombin and antithrombin III (AT III) variations have been studied in blood, urines and liver during an experimental nephrotic syndrome in rats (Heymann nephritis). A quantitative morphometric study (light microscopy) has been performed in the liver using an immunocytochemical technique--(PAP) method--to evaluate the protein synthesis by the number of protein-containing hepatocytes. Some sections were also studied by electron microscopy. The nephrotic animals were compared with control rats. In the blood of nephrotic rats, fibrinogen and prothrombin concentrations were increased and albumin and AT III concentrations were decreased. In the urines of nephrotic rats, albumin, prothrombin and AT III were lost, but no fibrinogen. The morphometric study in the liver has shown a significantly higher number of fibrinogen and prothrombin-containing hepatocytes in nephrotic rats than in controls, suggesting an increased synthesis of these proteins; no change was observed concerning albumin and AT III between nephrotic and control animals. In electron microscopy, albumin was demonstrated in Golgi apparatus, proving that the peroxidase-positive cells are related to protein synthesis. These results show that the mechanisms of regulation of the protein synthesis during nephrotic syndrome are different from one protein to another and, particularly, that their blood level is not the only regulating factor for their synthesis.

Albumins↗