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PubMed1994

[Antithrombin therapy in acute coronary syndromes].

Intracoronary thrombosis is fundamental in the pathogenesis of acute coronary syndromes, although the causes of thrombosis are still unclear. As thrombin generation is crucial for thrombus formation, the inhibition of thrombin is a primary aim to prevent the evolution of an initial repair process into a pathological thrombus. Thrombin inhibition can be achieved by several drugs. Heparin is the principal antithrombin drug currently used in acute syndromes; it acts mainly by binding to antithrombin III and increasing its inhibitory effect on thrombin and other coagulation factors. The heparin-antithrombin III complex, however, does not inhibit thrombus-bound thrombin; moreover, iv heparin requires frequent laboratory monitoring and dose adjustments. Despite these limitations, continuous infusion of i.v. heparin has been found to be effective in unstable angina and in myocardial infarction, especially when treated with accelerated rt-PA. New antithrombin drugs that selectively and directly inhibit thrombin are hirudin, its synthetic derivate hirulog, and argatroban. These drugs have several theoretical advantages over heparin: greater stability of the aPTT--with the need for less laboratory monitoring--and greater efficacy--associated mainly with its capacity to inhibit clot-bound thrombin. Clinical pilot studies seem to indicate a greater antithrombotic efficacy compared with heparin, but a greater number of hemorrhagic events in patients with acute myocardial infarction receiving thrombolysis. In conclusion, the use of heparin is certainly indicated in patients with unstable angina and persistent ischemia and in acute myocardial infarction treated with accelerated rt-PA. The use of new antithrombin drugs, although promising, requires further clinical evaluation.

Acute Disease↗

PubMed1999

A case of ovarian hyperstimulation syndrome in which antithrombin III deficiency occurred because of its loss into ascites.

OBJECTIVE: To present a case of ovarian hyperstimulation syndrome in which antithrombin III activity in plasma was decreased and in ascites was increased. DESIGN: Case report. SETTING: Hospital-based clinic for reproductive medicine. PATIENT(S): A 27-year-old woman who was transferred to our hospital because of ovarian hyperstimulation syndrome. INTERVENTION(S): Induced abortion. MAIN OUTCOME MEASURE(S): Antithrombin III activity in plasma and ascites. RESULT(S): Antithrombin III activity in ascites was slightly lower than that in plasma. CONCLUSION(S): The loss of antithrombin III into ascites probably caused its deficiency in this case.

Adult↗

PubMed1980

Plasminogen and antithrombin III deficiencies in the childhood nephrotic syndrome associated with plasminogenuria and antithrombinuria.

Three of four patients with the childhood nephrotic syndrome were found to have low plasma plasminogen concentrations; all four had low plasma antithrombin III concentrations. In the two patients who were tested, urinary concentrations of these proteins exceeded the plasma concentrations. As the urinary losses of plasminogen and antithrombin III decreased over the course of illness, the plasma concentrations of antithrombin III and plasminogen rose. One patient had multiple thromboembolic episodes. We conclude the deficiencies of antithrombin III and plasminogen, probably secondary to urinary excretion of these proteins, may contribute to the thrombotic diathesis associated with nephrotic syndrome.

Adolescent↗

PubMed1976

Oral contraceptives, antithrombin- III activity, and postoperative deep-vein thrombosis.

Deep-vein thrombosis (D.V.T.) was detected by the fibrinogen-uptake test in six out of a total of thirty-one young women undergoing emergency abdominal surgery who gave a history of recent oral contraceptive intake. In contrast, no D.V.T. developed in nineteen similar patients who were not on oral contraceptives (P less than 0-01). Plasma-antithrombin-III activity was significantly lower preoperatively in patients taking oral contraceptives; postoperative D.V.T. subsequently developed in three out of five patients with preoperative antithrombin-III activity below 50%. In seventy-eight dental patients undergoing molar extraction, antithrombin-III activity was measured before, during, and after operation. Activity fell in all patients during operation, but the fall was significantly greater in women taking oral contraceptives (P less than 0-01). The intra-operative fall in antithrombin-III activity was prevented by a small preoperative dose of subcutaneous heparin.

Adolescent↗

PubMed1988

Pathophysiology of antithrombin III deficiency.

This article focuses on the pathophysiology of thrombosis in patients with acquired antithrombin III deficiency. Antithrombin III is an important natural inhibitor of the hemostatic mechanism, and a hypercoagulable state is often induced in diseases causing antithrombin III deficiency. Laboratory determination of antithrombin III activity is particularly useful in the clinical evaluation and therapeutic management of patients with disseminated intravascular coagulation, nephrotic syndrome, and severe hepatopathy.

Animals↗

PubMed1983

Molecular heterogeneity of inherited antithrombin III deficiency.

Inherited antithrombin III deficiency is associated with an increased risk of thromboembolism. Using recombinant-DNA techniques, we isolated a molecular probe for the antithrombin III structural gene and identified a common DNA polymorphism within the gene. We found that there is genetic heterogeneity in this disorder. In one family, the antithrombin III gene was deleted in affected members, whereas in another no deletion occurred. Use of the DNA polymorphism should allow identification and further characterization of abnormal antithrombin III genes.

Adolescent↗

PubMed1980

An improved clinical assay for antithrombin III (heparin cofactor).

A method for determining antithrombin-III heparin cofactor activity that requires no defibrinogenation of plasma, can be used with heparinized samples, and is specific for antithrombin-III heparin cofactor activity was developed. The procedure requires minimal pipetting, uses small amounts of sample over a single short incubation period, and is relatively inexpensive. The antithrombin-III assay appears to be superior to other commercially available procedures when employed in the diagnosis of deficiencies and in the identification of decreased levels of antithrombin III associated with liver disease and thrombotic disorders.

Antithrombin III↗

PubMed1983

False assignment of familial antithrombin III deficiency with the von Kaulla assay.

As a serum assay, the von Kaulla assay for antithrombin III has been criticized on the grounds that consumption of antithrombin III during in vitro blood clotting may lead to falsely low assay values. Use of the assay to screen a Utah pedigree for familial antithrombin III deficiency lends support to this criticism. In all, the assay was performed on 150 persons. Low values on the assay were corroborated by performing an alternative coagulation assay, an amidolytic assay, and an immunoassay. While all persons with historic evidence for a diagnosis of familial antithrombin III deficiency had low assay values, eight of 23 persons with low values had normal values on the other assays.

Adolescent↗

PubMed1999

Combined antithrombin III and C1-esterase inhibitor treatment decreases intravascular fibrin deposition and attenuates cardiorespiratory impairment in rabbits exposed to Escherichia coli endotoxin.

OBJECTIVE: To assess the effect of a combined antithrombin III and C1-esterase inhibitor treatment on intravascular organ fibrin deposition and cardiorespiratory changes following intravenous Escherichia coli endotoxin (lipopolysaccharide [LPS] 80 microg/kg i.v.) exposure. DESIGN: Prospective, randomized trial. SETTING: Research laboratory of a university medical center. SUBJECTS: Anesthetized, instrumented and mechanically ventilated rabbits ([Chbb:CH); n = 40). INTERVENTIONS: Endotoxin was given to 30 animals. Ten animals received no inhibitor (endotoxin control group). The other animals were either treated by high-dose (300 units/kg; n = 10) or low-dose (100 units/kg; n = 10) combined antithrombin III and C1-esterase inhibitor administration. Ten rabbits (time control group) were given placebo (sodium chloride 0.9%). Cardiorespiratory variables were assessed at baseline, 120 mins, and 240 mins after endotoxin or placebo administration. Four hours after endotoxin injection, liver, lung, and kidney tissue samples were examined for intravascular fibrin deposition by light microscopy. MEASUREMENTS AND MAIN RESULTS: Inhibitor treatment significantly decreased clot formation in lungs and livers without, however, demonstrating a clear dose-dependent effect. Combined antithrombin III/C1-esterase treatment attenuated the decrease of mean arterial pressure and cardiac output observed following endotoxin injection. Blood pressure improvement was significantly dependent on dosage administered. CONCLUSION: Combination of antithrombin III and C1-esterase inhibitor treatment during early endotoxin shock decreased organ fibrin deposition and improved cardiovascular stability.

Animals↗

PubMed2000

Complete antithrombin deficiency in mice results in embryonic lethality.

Antithrombin is a plasma protease inhibitor that inhibits thrombin and contributes to the maintenance of blood fluidity. Using targeted gene disruption, we investigated the role of antithrombin in embryogenesis. Mating mice heterozygous for antithrombin gene (ATIII) disruption, ATIII(+/-), yielded the expected Mendelian distribution of genotypes until 14.5 gestational days (gd). However, approximately 70% of the ATIII(-/-) embryos at 15.5 gd and 100% at 16.5 gd had died and showed extensive subcutaneous hemorrhage. Histological examination of those embryos revealed extensive fibrin(ogen) deposition in the myocardium and liver, but not in the brain or lung. Furthermore, no apparent fibrin(ogen) deposition was detected in the extensive hemorrhagic region, suggesting that fibrinogen might be decreased due to consumptive coagulopathy and/or liver dysfunction. These findings suggest that antithrombin is essential for embryonic survival and that it plays an important role in regulation of blood coagulation in the myocardium and liver.

Animals↗

PubMed1989

CpG dinucleotides are "hotspots" for mutation in the antithrombin III gene. Twelve variants identified using the polymerase chain reaction.

CpG dinucleotides have been implicated as mutational hotspots in genes that are subject to control mechanisms involving methylation. We have used the polymerase chain reaction to amplify exons 2 and 6 of the human antithrombin III gene and direct sequencing to identify the base replacement in 12 genetic variants. These occurred in individuals with a history of thromboembolic disease due to functional abnormalities of circulating antithrombin: ten had decreased heparin binding and activation, two had decreased inhibitory activity. The amino acid abnormality in ten out of 12 cases had arisen at a CpG dinucleotide; this confirms the CpG sequence as a "hotspot" in the antithrombin gene and explains the observed frequency of occurrence of the same variant antithrombins in diverse populations.

Antithrombin III↗

PubMed1983

[Antithrombin V--a rare concomitant symptom in plasmacytoma and autoimmune diseases].

Antithrombin V as a pathological inhibitor of coagulation may occur in some rare cases as an accompanying symptom of various basic diseases. In the course of two years, antithrombin V could be identified in 8 patients, with plasmocytoma, lupus erythematodes visceralis, glomerulonephritis or colitis ulcerosa existing as basic diseases. Clinical findings in patients and those gained in analyzing coagulation, procedures of laboratory diagnostics for determining characteristic properties of antithrombin V as well as the therapeutic way of influencing the activity of antithrombin V are represented.

Adolescent↗

PubMed1984

[Treatment of deep venous thrombosis in the presence of a congenital antithrombin III deficiency. Apropos of the use of purified concentrates].

The authors report the case of an active 32 year old man who developed right leg DVT. Before heparinisation, he was discovered to have a low antithrombin III level (biological activity (B) 60%, immunological level (I) 50) and a further inquiry showed the same abnormality in 4 members of the family, leading to a diagnosis of a congenital deficit: a 35 year old sister with a bilateral post-DVT changes had antithrombin III levels of 70% (B) and 45% (I); two nephews, sons of the affected sister: the one aged 5 years was asymptomatic despite antithrombin III levels of 50% (I) and 70% (B); the other had experience DVT at the age of 2 and, on oral anti-vitamin K drugs, had antithrombin III levels of 55% (I) and 67% (B) at the age of 15 years; the patient's brother died at the age of 29 of cerebral vein thrombosis after pulmonary embolism. The recurrence of local signs of DVT after 12 day's heparin therapy with AT III levels (B) of 40%, led to a change in management with infusion of purified AT III concentrate at a dose of 40 U per kg (2 500 U per hour). This induced a rise in AT III activity to over 100% and enabled early introduction of anti-vitamin K therapy. The patient remains asymptomatic after 6 months follow-up. This case illustrates the value of determining AT III activity in all patients who developed DVT without obvious reason.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

[Clinical problems posed by the consumption of antithrombin III induced by heparin].

Two cases of resistance to the heparin treatment, induced by large consumption of antithrombin III, are reported. Normally small, this consumption does not automatically call for the systematic dosage of Antithrombin III for each treatment using heparin. On the other hand, any clinical or biological resistance to higher doses of heparin, any personal or family history of thrombosis necessitate the administration of Antithrombin III. Where there is an acquired or congenital deficit, an injection of Antithrombin III corrects the disorder and reduces the risk of thrombosis. In the case of a heparin-antivitamin K relay, it is essential to achieve complete biological effectiveness of the antivitamins K to interrupt the administration of the heparin.

Adult↗

PubMed1982

Familial antithrombin III deficiency.

Antithrombin III is the major physiological inhibitor of the coagulation mechanism and a deficiency of this protein results in a marked predisposition to venous thromboembolic disease. Three Scottish families with a deficiency of this protein are described and other reported families are reviewed. The properties, functions and methods of assay of antithrombin III are outlined; the molecular abnormalities, inheritance, clinical and laboratory characteristics of antithrombin III deficiency are described, and the use of antithrombotic drugs and human antithrombin III concentrates in this deficiency is discussed.

Adolescent↗

PubMed1994

Antithrombin III: summary of first database update.

Antithrombin III is the most important inhibitor of coagulation proteinases such as thrombin and factor Xa. Inherited deficiency of antithrombin III is a well recognised risk factor for the early development of venous thromboembolism. The gene for antithrombin III is located at chromosome 1q 23-25 and its structural organisation has been described. A database of mutations of the antithrombin III gene has been compiled and a recent update lists 184 entries. These entries are listed according to subtype of deficiency and to nucleotide sequence number. There are 68 reports of type I 'classical' and 116 reports of type II 'variant' deficiencies. This summary considers the entries in terms of the number of unique molecular events, the nature of the genetic defects and the role of CpG dinucleotides in deficiency. Sample listings of type I and II deficiency entries are provided.

Antithrombin III↗

PubMed1993

[A case of familial antithrombin III variant complicated by recurrent pulmonary infarction].

We present a 36-year-old male who developed pulmonary infarction secondary to antithrombin III variant. He was admitted to our hospital with progressive chest pain and hemosputum. The presence of multiple defects on 99mTc perfusion scan indicated the diagnosis of pulmonary infarction. He had a past history of pulmonary infarction 4 years before this episode as well as a family history of recurrent thromboembolic disease. Through coagulation studies revealed that the concentration of antithrombin III antigen and progressive antithrombin activity were within normal limits, while heparin cofactor activity was decreased markedly. Of 5 people in his family, 4 proved to have low heparin cofactor activity. These data suggest that functional abnormality of antithrombin III seems to be closely associated with pulmonary infarction.

Adult↗

PubMed2001

Synthesis of conformationally locked L-iduronic acid derivatives: direct evidence for a critical role of the skew-boat 2S0 conformer in the activation of antithrombin by heparin.

We have used organic synthesis to understand the role of L-iduronic acid conformational flexibility in the activation of antithrombin by heparin. Among known synthetic analogues of the genuine pentasaccharidic sequence representing the antithrombin binding site of heparin, we have selected as a reference compound the methylated anti-factor Xa pentasaccharide 1. As in the genuine original fragment, the single L-iduronic acid moiety of this molecule exists in water solution as an equilibrium between three conformers 1C4, 4C1 and 2S0. We have thus synthesized three analogues of 1, in which the L-iduronic acid unit is locked in one of these three fixed conformations. A covalent two atom bridge between carbon atoms two and five of L-iduronic acid was first introduced to lock the pseudorotational itinerary of the pyranoid ring around the 2S0 form. A key compound to achieve this connection was the D-glucose derivative 5 in which the H-5 hydrogen atom has been replaced by a vinyl group, which is a progenitor of the carboxylic acid. Selective manipulations of this molecule resulted in the 2S0-type pentasaccharide 23. Starting from the D-glucose derivative 28, a covalent two atom bridge was now built up between carbon atoms three and five to lock the L-iduronic acid moiety around the 1C4 chair form conformation, and the 1C4-type pentasaccharide 43 was synthesized. Finally the L-iduronic acid containing disaccharide 58 which, due to the presence of the methoxymethyl substituent at position five adopts a 4C1 conformation, was directly used to synthesize the 4C1-type pentasaccharide 61. The locked pentasaccharide 23 showed about the same activity as the reference compound 1 in an antithrombin-mediated anti-Xa assay, whereas the two pentasaccharides 43 and 61 displayed very low activity. These results clearly establish the critical importance of the 2S0 conformation of L-iduronic acid in the activation of antithrombin by heparin.

Antithrombins↗