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PubMed1999

Prothrombin 20210G/A mutation in two patients with mesenteric ischemia.

Primary cases of splanchnic vein thrombosis are now less common since a systematic screening for hypercoagulability is performed. In 1996, a sequence variation in the 3'-untranslated region of the prothrombin gene (F.II 20210G/A mutation) has been linked to a threefold increased risk for venous thrombosis. The role of this thrombophilic disorder is not documented in patients with thrombosis of the splanchnic veins. This report presents two patients with a mesenteric ischemia associated with a heterozygous state for the F.II 20210G/A mutation. The first patient developed an ischemic colitis and the second one an ischemic necrosis of the terminal ileum related to a thrombosis of the superior mesenteric vein. In both cases, another thrombotic risk factor was associated: either a general prothrombic state (primary antiphospholipid syndrome) or a focal factor (abnormal hemodynamic conditions related to a liver cirrhosis). It has recently been proposed that several conditions need to be combined for deep vein thrombosis to develop. Screening for the combination of multiple underlying prothrombotic conditions thus appears justified in patients with splanchnic thrombosis. The role of the F.II 20210G/A mutation as a predisposing factor for thrombosis of the digestive vessels should be considered and needs further investigation.

Adult↗
PubMed2004

Factor V G1691A, prothrombin G20210A, and methylenetetrahydrofolate reductase [MTHFR] C677T gene polymorphism in angiographically documented coronary artery disease.

BACKGROUND: Single point mutations in the genes coding for factor V [G1691A; Leiden], prothrombin [PRT; G20210A], and methylenetetrahydrofolate reductase [MTHFR, C677T] were shown to be major inherited predisposing factors for venous thromboembolism. However, their contribution in the development of coronary artery disease [CAD] remains controversial. The aim of the study was to examine the association of these mutations in CAD. METHODS: A total of 96 patients with angiographically-demonstrated CAD [mean age 55.3 +/- 11.3], and 404 healthy subjects [mean age 50.7 +/- 8.9] were recruited into the study. Fasting plasma homocysteine was determined by HPLC, and genotype analysis was assessed by PCR-RFLP. RESULTS: The carrier frequency of factor V-Leiden (14.6% vs. 15.1%, p = 0.617) and PRT G20210A (3.1% vs. 3.0%; p = 0.936) were similar between patients and controls, respectively. In contrast, the frequency of the MTHFR variant C677T was 71.9% among patients compared with 45.5% in controls (p < 0.001), of which the T/T genotype was significantly higher among patients (31.3%) than controls (4.5%; p < 0.001). Significantly higher homocysteine levels were seen among T/T genotype in both groups compared to non-T/T carriers (p < 0.05), and among patients compared with controls (18.47 +/- 3.73 micromol/L vs. 16.28 +/- 4.16 micromol/L). In addition, the coexistence of MTHFR C677T with FV-Leiden was seen in 10.4% of CAD patients compared 6.9% of controls (p = 0.001). CONCLUSION: While results from this study clearly demonstrate a strong association of hyperhomocysteinemia and homozygosity of the MTHFR C677T, but not FV-Leiden or PRT G20210A, mutations with confirmed CAD, they also suggest a potential role for factor V-Leiden in MTHFR C677T carriers.

Adult↗
PubMed2003

Des-gamma-carboxy prothrombin (DCP) ratio, a novel parameter measured by monoclonal antibodies MU-3 and 19B7, as a new prognostic indicator for hepatocellular carcinoma.

BACKGROUND/AIM: Recently, a novel des-gamma-carboxy prothrombin (DCP) antibody named 19B7 has been developed. It has been reported that the DCP ratio defined by DCP measured by MU-3 antibody/DCP measured by 19B7 antibody demonstrated differences between hepatocellular carcinoma and vitamin K deficiency. The aim of this study was to clarify the relationship between the DCP ratio and tumour malignancy, as well as the prognostic significance of the DCP ratio after hepatectomy for hepatocellular carcinoma. METHODS: From January 1996 to December 1999, 79 patients diagnosed with hepatocellular carcinoma underwent hepatectomy. To detect DCP in the plasma before surgery, we used a new EIA kit, Eitest PIVKA-II kit (Eisai, Tokyo, Japan) with both MU-3 and 19B7 antibody. The DCP ratio was calculated using the formula: DCP ratio = DCP level measured by MU-3 antibody (mAU/ml)/DCP level measured by 19B7 antibody (mAU/ml). Pathologic findings using resected specimens were classified according to the Japanese General Rules for Primary Liver Cancer. RESULTS: Among DCP-positive patients, the DCP ratio was significantly higher in those with tumour thrombus in the portal vein (vp) or with a moderately or poorly differentiated hepatocellular carcinoma than in those without vp or with a well-differentiated carcinoma (P = 0.0162, 0.0109, respectively). Patients with DCP ratio > 3 had a significantly higher incidence of vp than those with DCP ratio < or = 3 (P = 0.0027). The survival rate was significantly higher in patients with DCP ratio < or = 3 than in those with DCP ratio > 3 (P = 0.0002). This result was the same as in DCP positive cases (P = 0.0027). CONCLUSIONS: The DCP ratio can distinguish DCP produced by hepatoma cells from DCP produced by normal hepatocytes in vitamin K deficiency. The DCP ratio is a useful prognostic indicator that can be assessed before hepatectomy.

Aged↗
PubMed1996

Further evidence linking urolithiasis and blood coagulation: urinary prothrombin fragment 1 is present in stone matrix.

The fact that organic material is always present and distributed throughout each renal calculus suggests that it may play a role in stone formation. The organic matrix of calcium oxalate (CaOx) crystals freshly generated in urine in vitro contains urinary prothrombin fragment 1 (UPTF1) as the principal protein. In this initial study, matrix was extracted from 12 renal calculi and evaluated for the presence of UPTF1 using Western blotting. UPTF1 was present in all eight stones whose principal component was CaOx, and in one of two stones which consisted mainly of calcium phosphate (CaP). UPTF1 was absent from the two struvite calculi examined. The relationship between CaP and UPTF1 was explored further. Matrix harvested from CaP crystals freshly generated in urine in vitro was also shown to contain UPTF1 as its principal component. Our inability to detect UPTF1 in one mixed CaOx/CaP stone may be related to our methods of matrix retrieval, while its absence from two struvite stones argues against it being present in the other stones merely as a consequence of passive inclusion. This absence may be related to the alkaline environment typical of struvite stone growth. The finding that UPTF1 is present in some renal stones provides the first direct evidence that links blood coagulation proteins with urolithiasis.

Adult↗
PubMed2003

Tricuspid valve thrombus and pulmonary embolus in an infant with homozygous thermolabile methylenetetrahydrofolate reductase and heterozygous prothrombin G20210A variant.

We describe an unusual and interesting case of a full-term infant presenting at 7 days of life with HSV pneumonitis and a tricuspid valve thrombus ultimately requiring extracorporeal membrane oxygenation. The infant subsequently developed a pulmonary embolus. The infant was found to be heterozygous for the prothrombin G20210A mutation and homozygous for the methylenetetrahydrofolate reductase C667T mutation. The patient was treated with low molecular weight heparin for a total of 3 months and has not had a recurrent thrombosis. This case illustrates that a combination of congenital and acquired thrombophilic risk factors can contribute to a significant thrombotic event.

Coronary Thrombosis↗
PubMed2003

Therapeutic concordance of two portable monitors and two routine automatic oral anticoagulant monitoring systems using as reference the manual prothrombin time technique.

Two models of capillary blood prothrombin time (PT) monitoring systems were evaluated for analytical performance and then compared with two routine PT systems using the reference manual technique and a high-sensitivity thromboplastin. Two sets of 60 and 80 plasmas were analyzed from anticoagulated patients stabilized over 3 months in an INR range 2-3.5 for therapy. Capillary PT determination was performed in two portable monitors, CoaguChek S and CoaguChek PT (Roche Diagnostics), and plasma automatic methods were Neoplastine/STA (Diagnostics Stago) and PT-FibrinogenHsPlus/ACL7000 (Instrumental Laboratories). Thromboplastin Bilbao (TBi), an in-house high-sensitivity rabbit thromboplastin (ISI=1.08), recommended as the reference reagent by an External Spanish Oral Anticoagulant Quality Assessment, was used in the PT manual technique. The two monitors' coefficients of correlation with the reference system were 0.74 for CoaguChek S and 0.81 for CoaguChek PT. The automatic routine systems showed a correlation of 0.92 (Neoplastine/STA) and 0.91 (PT-FbHsPlus/ACL7000). Clinical agreement expressed as the percentage of simple correlation ranged between 75.0% (CoaguChek S) and 88.9% (Neoplastine/STA). The systems having the best kappa index with the manual technique were CoaguChek PT (71.9%) and the Neoplastine/STA system (73%). The routine PT management systems exhibited better correlation and percentage of concordance when using the TBi/manual technique than did the portable monitors, which moreover performed unequally in this regard.

Anticoagulants↗
PubMed2001

Simple, sensitive and accurate method for the quantification of prothrombin mRNA by using competitive PCR.

A method for the quantification of prothrombin (PT) mRNA species in hepatic tissues of rats was developed with the use of competitive PCR. To validate the quantification approach, sequential dilutions of total RNA from one of the samples were reverse transcribed. Their equivalent volumes were amplified together with a known amount of non-homologous competitor cDNA with identical nucleotide primers. The disparate sizes of target and competitor permitted the easy identification and quantification of bands in samples after densitometric analysis of ethidium bromide-stained agarose gels. Ratios of intensities of target and competitor bands were plotted against the initial amounts of total RNA species used, giving a linear relationship. The slope of this line was virtually identical with that obtained when the sample RNA was replaced with recombinant target cDNA, indicating that recombinant cDNA behaved in PCR identically with that made by reverse transcription and permitting the estimation of transcripts in reverse transcription reactions by using the recombinant counterpart of each as a standard. To avoid variation in the final results, the amount of competitor used in the assay was calculated separately from the equivalence point of the reverse-transcribed total RNA of one of the tissue samples; PCR was performed only for the minimum number of cycles required to detect products. A standard curve was made in each PCR run by amplifying differing amounts of recombinant cDNA species of PT or beta-actin together with a constant amount of its competitor. The numbers of transcripts in the tissues were then determined directly by PCR incorporating the same amount of respective competitor (as used in the standard curve) and comparing the ratios of products with the standard curve. Application of this method revealed that the median ratio of PT message to beta-actin message in hepatic tissues of 10 normal rats was 0.37, with a mean+/-S.D. of 0.37+/-0.07 (range 0.27-0.47). Although the method was developed for the quantification of PT transcripts in liver, it can easily be used for non-hepatic tissues as well. The technique is simple, quick and sensitive and requires only a very small amount of substrate.

Animals↗
PubMed1973

The preparation of activated factor X and its action on prothrombin.

The preparation of activated Factor X from reaction mixtures of bovine Factor X and Russell's-viper venom is described. The molecular weight of purified protein varies about a mean value of 40000; this variation is the result of at least two forms of Factor Xa. The action of activated Factor X, together with purified Factor V, was studied on purified prothrombin and the reaction products were isolated. In addition to thrombin, two other polypeptides with molecular weights of 16000 and 19500 were recovered.

Animals↗
PubMed1974

Changes in phylloquinone epoxidase activity related to prothrombin synthesis and microsomal clotting activity in the rat.

The oxidation of phylloquinone to the 2,3-epoxide (by phylloquinone epoxidase) was studied in liver from control and warfarin-resistant rats. The reaction requires microsomal fraction, soluble protein, a heat-stable soluble factor and O(2). It is not inhibited by CO or CN(-). Epoxidase activity was stimulated if plasma prothrombin was lowered either by anticoagulants or the absence of vitamin K. The activity of the enzyme rapidly returned to normal values after the administration of vitamin K to hypoprothrombinaemic rats. These differences in the activity of the enzyme occur in the microsomal fraction and not the cytosol. A thrombin-generating polypeptide that accumulates in microsomal fraction of hypothrombinaemic rats correlated directly with epoxidase activity. These data support the view that enzymic interconversion of phylloquinone and its 2,3-epoxide participates in the biological activity of vitamin K.

Animals↗
PubMed1974

The localization of a vitamin K-induced modification in an N-terminal fragment of human prothrombin.

1. The N-terminal fragment (PF-I) split off from prothrombin during coagulation was purified to homogeneity from human serum. 2. The apparent molecular weight is 27000+/-2000 in sodium dodecyl sulphate-polyacrylamide-gel electrophoresis, whereas a value of about 19600 is obtained by calculation based on amino acid and carbohydrate analyses. The N-terminal sequence is an Ala-Asx bond. The fragment contains about 16% carbohydrate, binds phospholipids in the presence of Ca(2+) and is adsorbed to BaSO(4). The pK(a) of its BaSO(4)-binding group(s) is 3.1-3.5. 3. By CNBr cleavage of fragment PF-I two peptides (C-1 and C-2) were obtained with molecular weights of about 5900 (C-2) and 12400 (C-1) on the basis of amino acid and carbohydrate analyses. Only the smaller (N-terminal) peptide is adsorbed to BaSO(4) and, since the ability of the whole protein to bind to BaSO(4) is known to be absent in samples obtained from patients treated with vitamin K antagonists, this peptide probably contains the site of a modification to the structure of the protein which occurs during biosynthesis and depends on vitamin K. This peptide does not contain hexosamine or sialic acid.

Amino Acids↗
PubMed1976

Mass-spectrometric identification and sequence location of the ten residues of the new amino acid (gamma-Carboxyglutamic acid) in the N-terminal region of prothrombin.

The detailed mass-spectrometric evidence for our original findings [Magnusson et al. (1974) FEBS Lett. 44, 189-193] of ten gamma-carboxyglutamic acid residues in the N-terminal calcium-binding polypeptide of prothrombin is presented. The identification and sequence location of gamma-carboxyglutamic acid was made by electron-impact and field-desorption studies on acetyl permethyl peptide derivatives, and on the free amino acid. Details of the derivatives formed, and how this new amino acid may be easily recognized and sequenced from the mass spectrum, are given as a basis for future work.

Amino Acid Sequence↗
PubMed1979

The effects of calcium ions and pH on bovine prothrombin fragment 1. Intrinsic fluroescence studies.

The effects of pH and Ca2+ on the intrinsic fluorescence of bovine prothrombin fragment 1 were investigated to deduce the nature of protein functional groups involved in Ca2+ binding to fragment 1. From pH values of 9 to 3, increasing the H3O+ concentration results in quenching of the fluorescence of fragment 1. Reversible pH-titration curves are obtained which appear to consist of two regions. From pH 4 to pH6.5 a broad titration curve is obtained, whereas from pH6.5 to 9 a more pronounced titration behaviour is evidenced by a group or groups on fragment 1 with an apparent pKa of approx. 7.5. In contrast, the apparent association constant for Ca2+ and fragment 1 shows a sharp pH-dependence in the region between pH7 and 8 with tighter Ca2+ binding at higher pH values. A PKa of approx. 7.5 can be estimated for the group or groups on fragment 1 linked to the tight binding of Ca2+. Both H3O+ and Ca2+ result in blue-shifts in the wave-lengths of fragment-1 emission. These results are interpreted in terms of H+ - and Ca2+ - induced changes in the conformation of fragment 1 as a result of surface-charge neutralization.

Animals↗
PubMed1979

The nature of the slow metal ion-dependent conformational transition in bovine prothrombin.

Kinetic parameters characterizing the slow structural isomerization observed via metal ion-dependent intrinsic fluorescence quenching of bovine prothrombin Fragment 1 have been determined. From forward and reverse rate constants, an equilibrium constant of approx. 0.25 is calculated. This result is consistent with the hypothesis that there exists, in the absence of metal ions, an equilibrium between two forms of bovine Fragment 1, one of which can interact rapidly with Ca2+ and subsequently with phospholipid. The other form of Fragment 1 cannot interact with Ca2+ in a manner that yields a phospholipid-binding form of the protein. Interconversion of these two forms of Fragment 1 occurs and may involve the isomerization of a proline residue.

Animals↗
PubMed1990

Replacement of isoleucine-397 by threonine in the clotting proteinase factor IXa (Los Angeles and Long Beach variants) affects macromolecular catalysis but not L-tosylarginine methyl ester hydrolysis. Lack of correlation between the ox brain prothrombin time and the mutation site in the variant proteins.

Previously, from the plasma of unrelated haemophilia-B patients, we isolated two non-functional Factor IX variants, namely Los Angeles (IXLA) and Long Beach (IXLB). Both variants could be cleaved to yield Factor IXa-like molecules, but were defective in catalysing the cleavage of Factor X (macromolecular substrate) and in binding to antithrombin III (macromolecular inhibitor). In the present study we have identified the mutation of IXLA by amplifying the exons (including flanking regions) as well as the 5' end of the gene by polymerase-chain-reaction (PCR) method and sequencing the amplified DNA by the dideoxy chain-termination method. Comparison of the normal IX and IXLA sequences revealed only one base substitution (T----C) in exon VIII of IXLA, with a predicted replacement of Ile-397 to Thr in the mature protein. This mutation is the same as found recently for IXLB. The observation that IXLB and IXLA have the same mutation is an unexpected finding, since, on the basis of their ox brain prothrombin time (PT, a test that measures the ability of the variant Factor IX molecules to inhibit the activation of Factor X by Factor VIIa-tissue factor complex), these variants have been classified into two different groups and were thought to be genetically different. Our observation thus suggests that the ox brain PT does not reflect the locus of mutation in the coding region of the variant molecules. However, our analysis suggests that the ox brain PT is related to Factor IX antigen concentration in the patient's plasma. Importantly, although the mutation in IXLA or IXLB protein is in the catalytic domain, purified IXaLA and IXaLB hydrolyse L-tosylarginine methyl ester at rates very similar to that of normal IXa. These data, in conjunction with our recent data on Factor IXBm Lake Elsinore (Ala-390----Val mutant), strengthen a conclusion that the peptide region containing residues 390-397 of normal Factor IXa plays an essential role in macromolecular substrate catalysis and inhibitor binding. However, the two mutations noted thus far in this region do not distort S1 binding site in the Factor IXa enzyme.

Animals↗
PubMed1991

A novel one-step purification of human alpha-thrombin after direct activation of crude prothrombin enriched from plasma.

Crude prothrombin enriched from human plasma was directly activated to generate alpha-thrombin without prior exhaustive purification of the proenzyme using a combination of several different types of chromatographic techniques, as in all previously described methodologies. Activated thrombin was separated from other components in a single step by taking advantage of its highly specific affinity to heparin immobilized on a matrix support of Sepharose CL-6B. On the basis of the data presented herein, we have demonstrated the ease with which at least 25 mg of a highly purified enzyme (greater than 97% homogeneous by laser densitometry) can be obtained per litre of plasma. Our product exhibits a specific activity of at least 4000 National Institutes of Health units/mg and is stable after being freeze-dried for the purpose of long-term storage.

Amino Acids↗
PubMed2000

Phytomenadione or menadiol in the management of an elevated international normalized ratio (prothrombin time).

AIM: To evaluate the efficacy of oral menadiol compared to intravenous phytomenadione when correcting coagulopathies associated with cholestasis. METHODS: A total of 26 patients with cholestasis and an international normalized ratio (prothrombin time) greater than 1.2, were randomized to receive either 20 mg o.d. for 3 days of oral menadiol (n=12), or 10 mg o.d. of intravenous phytomenadione (n=14) prior to endoscopic retrograde cholangeopancreatography. Liver function tests and international normalized ratio were measured daily for 3 days. RESULTS: Liver function tests and international normalized ratio were comparable between groups at entry into the study (P > 0.05), but serum albumin was significantly lower in the intravenous phytomenadione group following treatment (P < 0.05). A decrease in international normalized ratio occurred in both groups following administration of vitamin K (P < 0.05). Two patients in the intravenous group required fresh frozen plasma, as failure to normalize international normalized ratio was observed. No adverse drug reactions were observed in either group, and no patient required re-admission for bleeding during a 4-week follow-up period after cholangeopancreatography. CONCLUSION: Oral menadiol appears to be an effective alternative to intravenous phytomenadione in the correction of coagulopathies associated with obstructive liver disease. This simplifies the care of patients with deranged clotting times requiring cholangeopancreatography, particularly those to be managed as out-patients.

Aged↗
PubMed1996

Prothrombin fragment 1+2 and thrombin-antithrombin complex levels in patients with inherited APC resistance due to factor V Leiden mutation.

Inherited activated protein C (APC) resistance is a newly described pathological condition associated with familial thrombophilia. A recent report on family with APC resistance showed increased levels of prothrombin fragment 1 + 2 (F1 + 2) in the affected individuals. No data concerning thrombin-antithrombin complex (TAT) levels in patients with inherited APC resistance are presently available. The aim of this study was to assess the plasma levels of F1 + 2 and TAT in patients with inherited APC resistance due to factor V (F.V) Leiden mutation and to evaluate F1 + 2 and TAT levels in symptomatic and asymptomatic patients with the defect ('carriers') as compared to their family members having no evidence of F.V Leiden mutation ('non-carriers'). One hundred and twenty-nine individuals belonging to 30 families with inherited APC resistance due to F.V Leiden mutation were studied. F1 + 2 and TAT levels were determined using two commercially available ELISA kits and cut-off values were defined as the higher limits of normal ranges obtained in healthy volunteers. Out of the 129 family members investigated, 36 were non-carriers, 85 were heterozygous and eight homozygous for F.V Leiden mutation. Thrombosis had occurred in 2/36 (6%) non-carriers, in 36/85 (42.3%) heterozygous and in 5/8 (63%) homozygous. Median levels of F1 + 2 and TAT were above cutoff values in carriers, whereas they were below in non-carriers. An overall percentage of 68.8% of carriers exhibited F1 +2 levels above the cut-off value as compared to 38.9% of non-carriers. For TAT, an overall percentage of 63.4% of carriers presented with levels above the cut-off compared with 28% of non-carriers. In conclusion, patients with inherited F.V Leiden mutation may exhibit increased levels of F1 + 2 and TAT. There are no differences in F1 + 2 and TAT median levels among symptomatic and asymptomatic carriers. The percentage of carriers of F.V Leiden with levels of F1 + 2 and TAT above cut-off appears to be higher than that found in other clotting inhibitors defects and in this respect the defect might be considered different. However, these findings and the presence of high percentage of non-carriers presenting with increased F1 + 2 and TAT levels may suggest the possible coexistence in these families of other unknown defects predisposing to thrombosis.

Adult↗