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PubMed1985

[Antithrombin III--an important factor in long-lasting microvascular operations].

Antithrombin III is an important factor in preventing thrombosis in the normal coagulation system. The antithrombotic effect of heparin is closely related to the presence of Antithrombin III (AT III) as cofactor. It is also known that the concentration of AT III decreases considerably during long-lasting gynaecological procedures and in visceral surgery. We have found that the serum concentration of AT III also decreases during long-lasting microvascular procedures as in free flap or toe transfers. The crucial points are the duration of the operation, the duration of ischaemia of the extremity and the preoperative concentration of AT III which heavily depends on the general condition of the patient. In ten cases the AT III concentration decreased by an average of 21.7%. In three patients the AT III factor decreased below the critical level of 80%. In these cases levels between 60 and 65% were measured at the end of long microvascular operations. This decrease of AT III can be avoided by application of the AT III factor in an active form during the procedure (AT III in solution with heparin). To avoid thrombosis of the anastomosed vessels the local application of AT III in its active form before anastomosis has proved very effective. In practice, measuring of the AT III level has proved to be very useful in long microvascular procedures before the operation and at intervals of two to four hours. Nevertheless, in spite of AT III application careful microsurgical anastomosis has to be made.

Administration, Topical↗
PubMed1985

Heparin and ionic strength-dependent conversion of antithrombin III from an inhibitor to a substrate of alpha-thrombin.

The stoichiometry of antithrombin III (AT) inhibition of alpha-thrombin (T) has been investigated in the presence and absence of heparin as a function of ionic strength by quantitative titration of enzyme active sites. In contrast to the ionic strength-independent stoichiometry of 1.0 mol of AT/mol of T observed in the absence of heparin, the presence of high-affinity heparin (HAH) resulted in an ionic strength-dependent increase in the apparent stoichiometry of inhibition from a molar ratio of 1.1 AT/T at an ionic strength of 0.3 to 9.8 mol of AT/T when the ionic strength was lowered to 0.01. Reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the reaction products revealed that the increased AT/T stoichiometry was due to preferential formation of a specific proteolytically cleaved form of AT that was indistinguishable from the previously characterized reactive site-cleaved AT (ATM). Using high-performance liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis to quantitate ATM, the cleaved inhibitor was shown to be formed rapidly and concomitant with the stable thrombin-antithrombin complex (TAT) and quantitatively accounted for the apparent increase in reaction stoichiometry at low ionic strength in the presence of HAH. The levels of HAH required to produce maximum ATM were catalytic at mu greater than or equal to 0.15, but became stoichiometric as the ionic strength decreased below 0.1. Substantially less ATM was produced in the presence of low-affinity heparin, while a low molecular weight HAH, virtually inactive in accelerating T inhibition by AT, was unable to promote significant ATM formation. These results indicate competition between substrate and inhibition reactions of AT with T which are affected by an ionic strength-dependent heparin interaction. A reaction mechanism accounting for these observations is proposed.

Antithrombin III↗
PubMed1979

[Thrombosis of the portal and superior mesenteric veins in a patient with a congenital and familial deficiency in antithrombin III (author's transl)].

Thrombosis of the visceral veins is an extremely rare condition in cases of congenital and hereditary deficiency of antithrombin III, associated with recurring venous thorbosis of the limbs. The authors report such a case in a man of 40 years of age, who had this deficiency, associated with thrombosis of the portal and superior mesenteric veins and a portal cavernoma. They stress the frequent association of recurring peripheral vein thrombosis, portal vein thrombosis in adults, and thrombosis of the mesenteric vein, and the importance of systematic measurements of antithrombin III levels in these pathological conditions.

Adult↗
PubMed1979

The effect of total hip replacement and general surgery on antithrombin III in relation to venous thrombosis.

This investigation was undertaken to identify and correlate one factor that makes patients undergoing total hip replacement more susceptible to venous thrombosis and pulmonary embolism than those who have almost any other elective orthopaedic procedure, and to determine why the operation of total hip replacement has proved to be relatively resistant to antithrombotic prophylaxis compared with general surgical procedures. Using the depletion of antithrombin III as a marker of activation of the coagulation system, two groups of patients were compared: twenty-one who were subjected to hip arthroplasty and fourteen who underwent general surgical procedures. Both during and after operation the decrease in the quantity of antithrombin III in hip-arthroplasty patients was significantly greater (p less than 0.05) than the decrease in general surgical patients. Seventy-three per cent of hip-replacement patients had venographic evidence of recent thrombosis, 60 per cent of which were discontinuous femoral-vein thrombi. Femoral-vein thrombosis occurs frequently in hip-arthroplasty patients and is relatively resistant to current antithrombotic prophylaxis. The data presented suggest that during hip surgery there is a strong systemic activation of the clotting cascade that is associated with local vessel injury and local stasis in the femoral vein, an association not found in most general surgical procedures.

Abdomen↗
PubMed1979

[Assay of antithrombin III and soluble fibrin complexes in the study of blood thrombophilia (author's transl)].

The authors conducted a series of experiments concerning the condition of hypercoagulability of patients with a history of thrombosis, in view of determining whether or not the risk of thrombosis could be assessed by laboratory tests. To that end they assayed antithrombin iii activity and soluble fibrin complexes in their test subjects. Antithrombin activity was assayed by a chromogenic method; soluble fibrin complexes by the hemoagglutination test. The activity of antithrombon III was significantly reduced in patients with venous thrombosis, not so in arterial thrombosis. Testing for soluble fibrin complexes was invariably unrewarding, probably because the thrombosis episodes under investigation were of too long standing.

Adolescent↗
PubMed1984

Antithrombin III determination by rate (kinetic) nephelometry.

Rate nephelometry immunological antithrombin III determination was elaborated with Beckman Immunochemistry System. The measuring can be carried out within 60 sec from 20 microliters plasma. The results show a close correlation with those of gained by the radial immunodiffusion method (r = 0.91( and by Coatest (Kabi-Ortho) (r = 0.77). Both laser-nephelometric and usual non-nephelometric anti-antithrombin III serum (Behring) may be applied.

Adult↗
PubMed1984

Fibrinogen, factor VIII related antigen, antithrombin III and alpha 2-antiplasmin in peripheral arterial disease.

In 306 subjects, 217 without and 89 with peripheral arterial disease (PAD), VIIIR:Ag and alpha 2-antiplasmin are significantly higher in PAD (p less than 0.01). In the PAD negative group the ratio alpha 2-antiplasmin/antithrombin III activity is significantly higher 1.11 +/- 0.3 in the patients with an abnormal exercise ECG typical of coronary disease than in normal subjects 1.02 +/- 0.2 (p less than 0.05). In the PAD positive group antithrombin III concentration is higher in patients with a normal exercise ECG than in patients with abnormal exercise ECG (p less than 0.05). The same is true for alpha 2-antiplasmin but not for the antithrombin III activity. Fibrinogen and VIIIR:Ag are higher in patients with a previous myocardial infarction, however, the age is also significantly different as compared to the group without previous myocardial infarction. Disturbance of the cerebral arterial circulation is characterized by an elevation of VIIR:Ag and of alpha 2-antiplasmin as compared to the values obtained in patients without this complication. There is a general tendency towards higher alpha 2-antiplasmin values with the extension of the arterial disease.

Antigens↗
PubMed1984

Improved assay conditions for automated antithrombin III determinations with the chromogenic substrate S-2238.

Assays for antithrombin III activity using the chromogenic substrate S-2238 were automated in various modifications on various instruments. Standard curves for the assay showed a deviating "0% point" in several but not all modifications. Addition of polyethylene glycol 6000/8000 (0.40-1.0%) minimizes this deviation. However, the deviation of the 0% point was not completely abolished in every modification of the test. Examination of Lineweaver-Burk plots showed nonlinearity at high concentrations of S-2238 as used in the antithrombin III assays. Addition of Tween-80 (0.01%) restores the Lineweaver-Burk plot and, at the same time, the standard curve in the assays is found to be linear. Therefore, we recommend the use of PEG 6000/8000 as well as Tween-80 in automated assay systems.

Antithrombin III↗
PubMed1984

Liver dysfunction rather than intravascular coagulation as the main cause of low protein C and antithrombin III in acute leukemia.

Protein C, a newly identified inhibitor of blood coagulation, was measured immunologically in 58 patients with untreated acute leukemias and compared with that of normal subjects. On the average, slightly lower values were found. However, the 17 patients with overt laboratory pictures of decompensated disseminated intravascular coagulation (DIC), including 11 cases with acute promyelocytic leukemia, had protein C concentrations no lower than those of the remaining 41 patients without DIC. Antithrombin III activity and antigen were normal and, like protein C, not lowered in DIC. The concentrations of both proteins were closely correlated with changes in the indexes for liver synthetic function. A subgroup of 13 patients with hyperleukocytic leukemias had lower protein C and antithrombin III, in line with the more compromised synthetic function of their livers. Our findings indicate that liver impairment rather than DIC is the main cause of the changes in the two naturally occurring inhibitors of blood coagulation.

Adult↗
PubMed1982

Pharmacological activities of heparins obtained from different tissues: enrichment of heparin fractions with high lipoprotein lipase, antihemolytic and anticoagulant activities by molecular sieving and antithrombin III affinity chromatography.

The pharmacological activities of 14 heparins prepared from bovine and hog tissues and heparin fractions obtained by molecular sieving on sephacryl S-200 and antithrombin III affinity chromatography are reported. Two groups of heparins can be distinguished regarding the lipoprotein lipase releasing activity (LPL) and the activated partial thromboplastin time (APTT). Heparins prepared from liver, lung, pancreas and thymus have a ratio of LPL/APTT of 3.6, whereas heparins prepared from placenta and intestine show a ratio of only 2.1. The heparin APTT, LPL, antihemolytic, antifactor Xa and anticoagulant activities were partially resolved by fractionation on Sephacryl S-200 chromatography and antithrombin III affinity chromatography. These results suggest the presence of a mixture of heparins with different pharmacological activities in a commercial preparation.

Animals↗
PubMed1982

Biochemical and functional study of antithrombin III in newborn infants.

Antithrombin III (AT-III) was isolated by heparin affinity chromatography from adult venous and newborn term and preterm umbilical cord blood. The purified proteins were compared by SDS-PAGE, rocket immuno-electrophoresis, protein concentration by microbiuret relative to optical density at 280 nm, heparin cofactor specific activity, progressive neutralization of thrombin and factor Xa at 37 degree C and pH related antithrombin kinetics. The structural evaluations revealed a fetal AT-III of molecular weight, charge and electrophoretic migration indistinguishable from adult AT-III. The functional studies showed that, on an equimolar basis, the rates of thrombin and Xa interactions with fetal AT-III were as rapid as those with adult AT-III. The catalytic rates of various concentrations of heparin were also equal. The newborn infant, therefore, displays a quantitative but not quantitative deficiency of AT-III.

Adult↗
PubMed1982

Studies of the prothrombin activation pathway utilizing radioimmunoassays for the F2/F1 + 2 fragment and thrombin--antithrombin complex.

We have evaluated the efficacy of utilizing radioimmunoassays (RIAs) for prothrombin activation fragments (F2/F1 + 2) and for thrombin--antithrombin complex (TAT) in purified systems and in whole blood. During venipuncture, appropriate anticoagulants were employed in order to prevent the generation of thrombin and factor Xa. The RIAs were shown to be specific for F2/F1 + 2 as well as TAT and did not interact with other plasma components. Initially, thrombin generation was studied in a purified human system of prothrombin, antithrombin, factor Xa, and factor V as well as phospholipid and Ca++. Under these conditions, the kinetics of F2/F1 + 2 and TAT generation were virtually superimposable. However, when factor V was omitted from the reaction mixture, a significantly greater amount of F2/F1 + 2 as compared to TAT was observable. Subsequently, prothrombin activation was monitored during the spontaneous coagulation of freshly drawn blood. Throughout the entire course of thrombin generation, the observable rate of formation of F2/F1 + 2 was considerably greater than that of TAT. We have examined the levels of F2/F1 + 2 and TAT in normal individuals. Our studies indicate that the concentrations of F1 + 2 and TAT average 1.97 nM and 2.32 nM, respectively. We have also quantitated the concentrations of F2/F1 + 2 and TAT in patients with disseminated intravascular coagulation. In these individuals, the levels of both components are elevated. However, the ratio of F1 + 2 to TAT ranges from 2.37 to 5.55. Thus, we conclude that under in vivo conditions, prothrombin activation is characterized by the accumulation of a stable precursor, such as prethrombin-2, and that this phenomenon may be related to an alteration of factor V function.

Antithrombins↗
PubMed1982

Antithrombin III deficiency: decreased synthesis of a biochemically normal molecule.

A 29-yr-old white female has suffered from recurrent venous thromboses over the last 12 yr. Plasma antithrombin III (AT-III) levels were 48% of normal by immunoelectrophoresis and 56% by chromogenic assay. Three of four siblings and the father had similar AT-III levels without associated venous thromboses. Heparin-Sepharose chromatography demonstrated normal behavior of the patient's AT-III. Her purified AT-III could not be distinguished from AT-III purified from a normal control either by SDS polyacrylamide gel electrophoresis or by crossed immunoelectrophoresis, and the heparin cofactor activity and the progressive antithrombin activity of both AT-III samples were identical. Turnover studies were made in the patient using her own purified AT-III labeled with 131I, (*I). The results did not differ significantly from studies made with autologous *I-AT-III in two normal control women. Her fractional breakdown rate of 0.54 total plasma AT-III per day compared with 0.45 and 0.52 in the controls. These studies indicate that the patient synthesizes a normal AT-III molecule at half normal rates.

Adult↗
PubMed1980

Characterization of a new potent heparin. 5th Communication: Further characterization by affinity chromatography on antithrombin-sepharose and its comparison with a commercially available heparin.

A highly potent heparin (Heparin Schering) was characterized in comparison to commercial heparin by affinity chromatography on antithrombin-III-sepharose. Heparin Schering consists of 83% high affinity and 17% low affinity fractions, whereas commercial heparin contained only 40% high affinity heparin and 60% low affinity heparin. The specific biological activities per microgram uronic acid and elution pattern on antithrombin-sepharose of high affinity heparin fraction were similar for both heparin preparations. It is concluded that the 2 times more potent anticoagulant activity of heparin Schering is mainly due to the enrichment of high affinity fraction (83%), which is also present in commercial heparin but at a remarkably lower percentage (40%).

Anticoagulants↗
PubMed1980

Structural studies on the carbohydrate portion of human antithrombin III.

Human antithrombin III has been shown to contain four identical N-glycosidically linked carbohydrate chain per molecule. These carbohydrate chains have been investigated by sugar and methylation analysis before and after removal of N-acetylneuraminic acid residues. The chains have been further investigated by Smith degradation, trifluoroacetolytic degradation, and degradation after chromium trioxide oxidation. As a result of these studies, the following structures is proposed for the carbohydrate chains in human antithrombin III: (formula: see text). NeuNAc, N-acetylneuraminic acid; Galp, galactopyranose; GlcNAcp, 2-acetamido-2-deoxyglucopyranose; Manp, mannopyranose are the abbreviations used in the structure.

Antithrombin III↗
PubMed1980

[Prophylaxis of consumption coagulopathy in shock. Dependence of the effect of heparin on the activity of antithrombin III (author's transl)].

In 16 patients admitted in shock, heparin prophylaxis for DIC was carried out. The effect of heparin was monitored by a series of coagulation tests. A distinct relation was found between the effect of heparin on the aPTT and on the thrombin clotting time and the activity of antithrombin III. Even a comparatively slight diminution of this activity resulted in a considerable decrease of the heparin effect on coagulation. Since this effect is of primary importance for the efficacy of prophylaxis of DIC, regular assays of antithrombin III are proposed in shock patients receiving heparin.

Adolescent↗
PubMedDate not supplied

Plasma von Willebrand factor and antithrombin III in patients submitted to open heart surgery.

Cardiovascular surgery for valve replacement led to a significant (p < 0.001) increase of plasma von Willebrand factor antigen level from 227% +/- 30.9 (x +/- SEM) recorded before surgery, to 397% +/- 40.7 at the end of the surgical procedure and the levels of this endothelia-derived glycoprotein remained high (427% +/- 38.9) 48 hours later. On the other hand plasma antithrombin III activity decreased from 85.4% +/- 8 before surgery, to 67.0% +/- 6 at the end of the surgical intervention and rose to 81.3% +/- 7, two days later. Lethal outcome occurred in a patient with initial low antithrombin III level (62%). These observations stress the importance of a thorough investigation of hemostatic variables in patients submitted to cardiovascular surgery.

Adult↗