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PubMed1998

[Prothrombin time and thromboplastin time. On-site measurement of the prothrombin time and activated partial thromboplastin time of surgical patients with laser photometry].

UNLABELLED: Turnaround time for analysis of prothrombin time (PT) and activated partial thromboplastin time (APTT) by standard laboratory methods ranges between 40 min and several hours. The delay in obtaining the test results limits their clinical utility for treatment of perioperative coagulation disorders and adequate anti-coagulation therapy. In this study, we compared on-site coagulation testing (OCT) of whole blood, which takes about 3 min, with standard laboratory plasma coagulation tests by our institutional laboratory (LAB) to assess the accuracy of the OCT in a clinical setting (abdominal and postcardiac surgery). METHODS: PT of 62 patients with abdominal surgery was measured intra- and postoperatively using both LAB (KC 40, Thromborel S, Centeon) and OCT (CoaguChek Plus, Boehringer Mannheim) systems. APTT was determined by LAB-(KC 40, Pathromtin, Centeon) and OCT-methods in 53 patients who underwent cardiac surgery requiring cardiopulmonary bypass. RESULTS: Linear regression demonstrated a strong and significant (p = 0.0001) correlation of OCT- and LAB-determinations both for PT (r = 0.92) and APTT (r = 0.91). For PT testing, bias analyses showed an agreement between OCT- and LAB-International Normalized Ratio (INR) (bias = 0.24; relative error = 14.6%) that was considered clinically acceptable, with 95% of the INR-differences lying between -0,26 and +0,74 (mean +/- 2 SD). Although commercial APTT-reagents usually differ in their sensitivity to heparin, we also found an acceptable agreement between OCT- and LAB-APTT values (bias = 6.7 s +/- 22 s; mean +/- 2 SD; relative error = 12%). CONCLUSION: On-site coagulation monitoring provides a rapid, convenient, and accurate assessment of coagulation that can both guide specific anti-coagulation therapy and optimize therapy control of coagulation disorders after cardiac and abdominal operations. As a consequence, OCT offers a valuable tool to reduce the inappropriate use of fresh frozen plasma and to improve cost-effectiveness.

Humans↗
PubMed2002

Clinicopathologic features of patients with hepatocellular carcinoma seropositive for alpha-fetoprotein-L3 and seronegative for des-gamma-carboxy prothrombin in comparison with those seropositive for des-gamma-carboxy prothrombin alone.

BACKGROUND: There has been no study of the clinicopathologic features of patients with hepatocellular carcinoma (HCC) who are seropositive for lectin-reactive alpha-fetoprotein (AFP-L3) alone, or seropositive for AFP-L3 and seronegative for des-gamma-carboxy prothrombin (DCP) in comparison with those who are seropositive for DCP alone. Thus, the present comparative study was performed. METHODS: The clinicopathologic features of HCC patients with either one or two tumors who underwent a hepatectomy (n = 88) were compared among the following five groups according to the seropositivity of AFP, AFP-L3 and DCP: (i) group A, seropositive for AFP above 100 ng/mL, AFP-L3 above 15% and DCP above 100 mAU/mL; (ii) group B, seropositive for AFP-L3 and seronegative for DCP below 40 mAU/mL; (iii) group C, seronegative for AFP below 20 ng/mL, AFP-L3 below 15% and seropositive for DCP; (iv) group D, seropositive for AFP and seronegative for AFP-L3 and DCP; and (v) group E, seronegative for AFP, AFP-L3 and DCP. RESULTS: Group B patients showed a higher incidence of infiltrative-type HCC with an irregular margin (P < 0.05) and a higher frequency of poorly differentiated HCC (P < 0.01) compared with group C patients. Group A patients had larger tumors and more massive-type tumors than group B patients. Our HCC cases showed that advanced clinicopathologic features were demonstrated in the order of group B, group C and group D. Group A and B patients and group D and E patients showed similar characteristics. CONCLUSIONS: Hepatocellular carcinoma patients who were seropositive for AFP-L3 and seronegative for DCP demonstrated clinicopathologic features of more advanced HCC compared with those who were seropositive for DCP alone.

Adult↗
PubMed2003

Role of prothrombin fragment 1 in the pathway of regulatory exosite I formation during conversion of human prothrombin to thrombin.

Prothrombin (Pro) activation by factor Xa generates the thrombin catalytic site and exosites I and II. The role of fragment 1 (F1) in the pathway of exosite I expression during Pro activation was characterized in equilibrium binding studies using hirudin(54-65) labeled with 6-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)hexanoate ([NBD]Hir(54-65)(SO3-)) or 5-(carboxy)fluorescein ([5F]Hir(54-65)(SO3-)). [NBD]Hir(54-65)(SO3-) distinguished exosite I environments on Pro, prethrombin 1 (Pre 1), and prethrombin 2 (Pre 2) but bound with the same affinities as [5F]Hir(54-65)(SO3-). Conversion of Pro to Pre 1 caused a 7-fold increase in affinity for the peptides. Conversely, fragment 1.2 (F1.2) decreased the affinity of Pre 2 for [5F]Hir(54-65)(SO3-) by 3-fold. This was correlated with a 16-fold increased affinity of F1.2 for Pre 2 in comparison to thrombin, demonstrating an enhancing effect of F1 on F1.2 binding. The active intermediate, meizothrombin, demonstrated a 50- to 220-fold increase in exosite affinity. Free thrombin and thrombin.F1.2 complex bound [5F]Hir(54-65)(SO3-) with indistinguishable affinity, indicating that the effect of F1 on peptide binding was eliminated upon expression of catalytic activity and exosite I. The results demonstrate a new zymogen-specific role for F1 in modulating the affinity of ligands for exosite I. This may reflect a direct interaction between the F1 and Pre 2 domains in Pro that is lost upon folding of the zymogen activation domain. The effect of F1 on (pro)exosite I and the role of (pro)exosite I in factor Va-dependent substrate recognition suggest that the Pro activation pathway may be regulated by (pro)exosite I interactions with factor Va.

4-Chloro-7-nitrobenzofurazan↗
PubMed2005

Novel fluorescent prothrombin analogs as probes of staphylocoagulase-prothrombin interactions.

Staphylocoagulase (SC) is a potent nonproteolytic prothrombin (ProT) activator and the prototype of a newly established zymogen activator and adhesion protein family. The staphylocoagulase fragment containing residues 1-325 (SC-(1-325)) represents a new type of nonproteolytic activator with a unique fold consisting of two three-helix bundle domains. The N-terminal, domain 1 of SC (D1, residues 1-146) interacts with the 148 loop of thrombin and prethrombin 2 and the south rim of the catalytic site, whereas domain 2 of SC (D2, residues 147-325) occupies (pro)exosite I, the fibrinogen (Fbg) recognition exosite. Reversible conformational activation of ProT by SC-(1-325) was used to create novel analogs of ProT covalently labeled at the catalytic site with fluorescence probes. Analogs selected from screening 10 such derivatives were used to characterize quantitatively equilibrium binding of SC-(1-325) to ProT, competitive binding with native ProT, and SC domain interactions. The results support the conclusion that SC-(1-325) binds to a single site on fluorescein-labeled and native ProT with indistinguishable dissociation constants of 17-72 pM. The results obtained for isolated SC domains indicate that D2 binds ProT with approximately 130-fold greater affinity than D1, yet D1 binding accounts for the majority of the fluorescence enhancement that accompanies SC-(1-325) binding. The SC-(1-325).(pro)thrombin complexes and free thrombin showed little difference in substrate specificity for tripeptide substrates or with their natural substrate, Fbg. Lack of a significant effect of blockage of (pro)exosite I of (pro)thrombin by SC-(1-325) on Fbg cleavage indicates that a new Fbg substrate recognition exosite is expressed on the SC-(1-325).(pro)thrombin complexes. Our results provide new insight into the mechanism that mediates zymogen activation by this prototypical bacterial activator.

Binding Sites↗
PubMed2002

Two antiprothrombin antibodies against prothrombin and prothrombin-phosphatidyl serine show partial but not total identity.

Recently, an enzyme-linked immunosorbent assay (ELISA) using prothrombin (PT) as the antigen has become a widely used test. Two ELISA methods for the detection of antiprothrombin antibody have been used extensively: one method employs PT as an antigen (aPT), and the other employs PT and phosphatidyl serine (aPT/PS) as antigens along with Ca. However, the results obtained by the two methods are not necessarily consistent with each other even using the same samples, suggesting the possibility that aPT and aPT/PS are different antibodies. We conducted an investigation to determine whether aPT and aPT/PS are identical or different antibodies. Five patients who were positive for both tests become negative to aPT after absorption with an aPT-ELISA plate or fluid-phase PT; however, they retained reactivity to aPT/PS after the same absorption procedure. These results suggest that aPT and aPT/PS are partially identical, yet still different antibodies. However, further examination employing more samples may be needed to verify our hypothesis including clarification of the clinicopathological significance of these antibodies in the future.

Adult↗
PubMed2006

Increased plasma prothrombin concentration in cirrhotic patients with portal vein thrombosis and prothrombin G20210A mutation.

It was the aim of the present study to investigate factor II levels in liver cirrhosis (LC) patients with portal vein thrombosis (PVT) carrying the heterozygous G20210A prothrombin (PT) mutation. Plasma concentrations of factor II, VII, X, V, protein C (PC) total protein S (tPS) antithrombin (AT) and D-dimers (DD) were measured in 13 LC patients with PVT heterozygous for PT G20210A, in 13 LC patients with PVT without PT G20210A and in 13 LC controls matched by age, sex and Child-Pugh score. Crude factor II and factor II/DD ratio were highest in LC patients with PVT heterozygous for PT G20210A (p = 0.03 and p = 0.02 respectively). The factor II/PC ratio, expression of a procoagulant/anticoagulant imbalance was highest in the same group (p = 0.0008). Plasma factor II levels are elevated in LC patients heterozygous for PT G20210A and may favour PVT.

Aged↗
PubMedDate not supplied

[A case of celiac disease with late diagnosis by very long prothrombin and activated partial prothrombin times].

Coeliac disease is usually revealed by intestinal symptoms, but less frequently by deficiency symptoms. Early screening is very important to avoid with appropriate diet an intestinal lymphoma or epidermoid cancer. We report here the case of a 68-year old woman where coeliac disease was pointed out by very long Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT). Clinical examination was strictly normal except for leanness, a small height, and several diarrhoea episodes 3 or 4 times a year. Other blood tests showed a macrocytic anemia, a fibrinogen level slightly above the upper limit, a decreased proteinaemia and albuminaemia, and a sideraemia at the lower normal limit. Liver tests pointed to a cytolysis. Vitamin K-dependent factors were decreased. A perfusion of vitamin-K allowed getting a normal PT. Duodenofiberscopy with biopsy allowed the diagnosis of coeliac disease. Neither lymphoma nor epidermoid cancer were detected. A gluten-free diet allowed the disappearing of digestive symptoms, weight rising and return to a normal PT. Searching for a coeliac disease is therefore relevant in aged patients even when very faint clinical or biological symptoms of malabsorption appear, particularly when PT is longer than the control with decreased vitamin-K dependant factors.

Aged↗
PubMed1991

Clinical evaluation of plasma abnormal prothrombin (des-gamma-carboxy prothrombin) in hepatobiliary malignancies and other diseases.

Des-gamma-carboxy prothrombin (DCP), a protein induced by vitamin K absence or antagonist-II (PIVKA-II) was measured in the plasma of patients with primary hepatocellular carcinoma and those with various other hepatobiliary and pancreatic diseases. DCP levels were determined by enzyme immunoassay (E-1023), using an anti-DCP monoclonal antibody. Forty-two of the 91 patients (46.2%) with hepatocellular carcinoma had abnormally elevated levels of DCP, whereas only one of the 24 patients with hepatic cirrhosis showed a slight increase. An increase was also observed in some patients with obstructive jaundice. There was no correlation between plasma levels of DCP and those of serum alpha-fetoprotein (AFP). In most patients with hepatocellular carcinoma, plasma DCP levels normalized after curative surgical resection. Plasma DCP levels were not related to the plasma concentration of vitamin K in the patients with hepatocellular carcinoma. Plasma DCP determination may be useful in the diagnosis and postoperative monitoring of the response of hepatocellular carcinoma.

Biliary Tract Diseases↗
PubMed1991

Abnormal prothrombin (DES-gamma-carboxy prothrombin) in hepatocellular carcinoma.

Des-gamma-carboxy prothrombin (DCP), a protein induced by vitamin K absence or antagonist-II (PIVKA-II) was measured by an enzyme immunoassay (E-1023) using anti-DCP monoclonal antibody in 92 patients with various hepatobiliary diseases. Thirty-six of the 38 patients (94.7%) with hepatocellular carcinoma (HCC) had abnormal DCP levels greater than 0.1 arbitrary unit (AU)/ml, but only 18 of the 35 patients (51.4%) had AFP greater than 100 ng/ml (suspicious levels for HCC). There was no correlation between plasma or serum DCP and serum alpha-fetoprotein (AFP) levels. Serum alpha fetoprotein was elevated (above 20 ng/ml) in 23 of the 35 patients (65.7%), and DCP was elevated in all of the remaining 12 patients with normal AFP. DCP levels returned to normal levels following curative hepatic resection or orthotopic liver transplantation for HCC. DCP is a useful tumor marker in the diagnosis and postoperative monitoring of patients with HCC.

Biomarkers↗