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PubMed1988

Induction of fibrinolysis by polyanions in human plasma.

The fibrinolytic potency of several polyanions was comparatively investigated. Fibrinolytic activity was measured in a whole plasma assay using H-D-Val-Leu-Lys-pNA (S-2251) as chromogenic substrate and by a fibrin plate assay using plasminogen rich fibrin plates. In the chromogenic substrate assay potent fibrinolytic polyanions comprised dextran sulfate, GAGPS, pentosan polysulfate, polyanethol sulfate, l-carrageenan and i-carrageenan. Chondroitin sulfates A, B, C, keratan sulfate, ribonucleic acid, k-carrageenan and heparin were weakly fibrinolytic. Hyaluronic acid and lipopolysaccharide from E. coli were inactive. Similar results were obtained when fibrinolytic activity was measured by a fibrin plate assay. All polyanions except lipopolysaccharide produced lysis zones. Induction of fibrinolytic activity in human plasma was shown to be at least partially dependent on Hageman factor. In factor XII deficient plasma no fibrinolysis was induced by any of the polyanions when measured in the fibrin plate assay. In the chromogenic substrate assay corn Hageman factor inhibitor (CHFI) inhibited the activation of S-2251 cleaving enzyme by GAGPS, pentosan polysulfate, polyanethol sulfate, heparin, and ribonucleic acid near completely. The activation by dextran sulfate was inhibited by 45%. Heparin, pentosan polysulfate and GAGPS, three polyanions of therapeutic interest were separately compared. In both assays GAGPS proved the most potent activator, while pentosan polysulfate exhibited 83% and 44% and heparin 32% and 14% of GAGPS fibrinolytic activity in the chromogenic substrate test and the fibrin plate assay, respectively.

Chromogenic Compounds↗
PubMed1996

Significance of IgG for the activity of factor XII measured in human plasma.

The plasma level of factor XII (FXII) was measured in samples from healthy young men. The activated contact factor was assayed as prekallikrein activator (PKA), as S-2222 amidase, and in radial immunodiffusion tests. By removing the bulk of IgG on protein G columns before the activation procedure, the functional activities increased to about 135%. In such test preparations, PAGE immunoblot experiments with polyclonal antibodies against FXII showed, in addition to FXIIa (80 kD), a double band with a molecular weight of about 46 kD. This protein could also be detected with a light-chain-specific monoclonal antibody to FXII, but not with such an antibody directed against its heavy chain. The 46-kD band was also observed in plasma deficient in FXII. The amidase assays indicated that the minor part of FXIIa was present in some kind of association with another protease. To obtain a correct estimation of total FXIIa in the amidase assays a sufficiently high level of FXI was required compared to that of FXII. The PKA assays were generally carried out with a prekallikrein (PK) substrate containing IgG. By replacing this substrate by PK free from IgG additional PKA activity was observed, the activity appearing also in plasma deficient in FXII.

Adult↗
PubMed1979

Evidence against collagen activation of platelet-associated factor XI as a mechanism for initiating intrinsic clotting.

Collagen activation of platelet-associated Factor XI has been proposed as a mechanism for initiating intrinsic clotting independent of Factor XII. Since this could explain the lack of bleeding in patients with hereditary Factor XII deficiency, prekallikrein deficiency and high molecular weight kininogen deficiency, we subjected the hypothesis to rigorous testing. Incubation of isolated platelets with collagen and calcium ions failed to generate activity shortening the clotting time of an activated Factor XI (XIa) assay that had been modified to eliminate effects due to platelet-associated activated Factor V. Nor could generation of traces of Factor XIa in such mixtures be detected by incubation with purified Factor IX and testing for the generation of activated Factor IX (IXa) in clotting and amidolytic assays. Moreover, when blood or platelet-rich plasma containing added 125I-Factor IX was incubated with calcium ions and collagen and then subjected to reduced sodium dodecyl sulfate polyacrylamide gel electrophoresis, the radioactivity profiles revealed only native 125I-Factor IX without evidence of the polypeptide chains of Factor IXa. The negative results of this study mitigate against the hypothesis that collagen activation of platelet-associated Factor XI represents a physiologically significant mechanism for initiating clotting independent of Factor XII.

Animals↗
PubMed1991

[Infective morbidity of replacement therapy in congenital coagulation deficiencies and its effects on demand of coagulation factors].

BACKGROUND: Analysis of the infective morbidity and mortality secondary to replacement hemotherapy in the population with congenital coagulation deficiencies (CCD) and their consequences on the demand for coagulation factors. METHODS: The 46 patients with CCD diagnosed in the autonomous community (AC) of the Balearic Islands (32 with hemophilia A, 6 with hemophilia B, 4 with von Willebrand's disease 2 with factor VII, 1 with factor X, and 1 with factor XII deficiencies) were investigated for infective morbidity and use of blood products from 1982 to 1987. RESULTS: 97% of the patients had some hepatitis marker, 77% had antibodies against human immunodeficiency virus (HIV) and 17% fulfilled the criteria for the acquired immunodeficiency syndrome (AIDS). There were 7 deaths (15%). The morbidity and mortality increased with age and use of blood products. There was a 46% reduction in factor VIII use between 1982 and 1986, from a mean yearly consumption per hemophiliac patient of 33444 international units (IU) to 18080 IU. CONCLUSIONS: The study results show a high prevalence of hepatitis and HIV, an important reduction in the demand of manufactured coagulation factors and a 15% reduction in the population with CCD during the study years.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Assay for Hageman factor (factor XII) in human plasma by means of chromogenic substrate for plasma kallikrein.

Determination of factor XII was performed in a test system where plasma samples were diluted (1/400-1/3200) in buffer and factor XII deficient plasma. Diluted CephotestR was used as activator and after 10 min activation time chromogenic substrate H-D-Pro-Phe-Arg-pNA was added. The assay was adopted to an enzyme analyzer. The reproducibility of the method was acceptable with a coefficient of variation of 7.8% in the normal range. The correlation of this method to a one-stage clotting assay for factor XII was good, r 0.79. The preliminary reference interval was calculated to be 52-147% of normal (mean+ 2 S.D.).

Chromogenic Compounds↗
PubMed2003

Perioperative use of the Thrombelastograph in patients with inherited bleeding disorders.

There are few reports of the use of Thrombelastgraph (TEG) in patients with isolated or inherited bleeding disorders. Three surgical patients are presented with von Willebrand's disease, factor XII deficiency, and hemophilia A with dysfibrinogenemia in which the abnormalities detected by the TEG were similar to the expected coagulation abnormalities based on preoperative laboratory studies. This initial report suggests that this potential application of the TEG be further investigated.

Adenoidectomy↗
PubMed1995

[Applicability of activated partial thromboplastin time (APTT) as a screening test of milk to medium deficiencies of coagulation factors in cats].

The present investigation examined if the aPTT shows sufficient sensitivity for single factor activities also in cats when measured with the test optimized for humans using a commercial reagent. Comparative measurements were done with different modifications of the aPTT (sample predilution, addition of fibrinogen). Measurements of the aPTT using different methods and the activity of the coagulation factors II, V, X, VIII, IX, XI, and XII were performed in 42 healthy cats in order to determine the reference ranges. The same measurements were done on 21 cat plasmas where at least one of the coagulation factors was diminished in relation to the corresponding reference range. The conventional aPTT reflected the decrease in coagulation factor activity in each of the 21 plasmas by prolongation above the reference range (14.6-24.4 s). The test thus possesses high sensitivity and is a suitable screening test also for the cat. In contrast, in tests with sample predilution the sensitivity was lower (3-4 false negative results). This was probably caused by the distinct increase of the range of the reference values.

Animals↗
PubMed1985

A contribution to the pathology of acquired plasma factor XIII deficiency.

The biologic activity of Factor XIII was measured in four groups of patients: 20 with liver cirrhosis, ten with acute DIC, 30 with acute leukemia with DIC, and 20 with acute leukemia without DIC. In all groups, the plasma Factor XIII transamidating activity was reduced, but this deficiency was more evident in patients with DIC alone or with leukemia and DIC. The immunologic determination of the a and b subunits of Factor XIII was also performed. Both subunits were below the normal range in the groups of patients studied, except for subunit b, which was normal in patients with leukemia without coagulopathy. Acute DIC patients showed an equally reduced level of both subunits, whereas in patients with leukemia, even in the presence of a complicating coagulopathy, a lesser decrease of subunit b than subunit a was found. Both subunits were equally reduced in patients with cirrhosis, suggesting an impaired synthesis of these proteins. In conclusion, our findings do not support the use of Factor XIII subunit measurements in distinguishing between thrombin- or protease-mediated consumption coagulopathy, and they seem to suggest that the deficiency pattern of the subunits is not accounted for by a simple pathogenetic mechanism.

Acute Disease↗
PubMed1999

Human homozygous type I plasminogen deficiency and ligneous conjunctivitis.

On the basis of a questionnaire sent to the ophthalmology departments of hospitals throughout Germany, 10 patients with ligneous conjunctivitis or pseudomembranous disease, ranging in age from 1 to 71 years were identified. All 10 patients had severely reduced plasminogen levels. Genetic analysis revealed homozygous type I plasminogen deficiency (which had not previously been described in humans) in 7 patients and compound heterozygous plasminogen deficiency in 1 patient. Clear differentiation was not possible in 2 patients. Most of the parents had heterozygous plasminogen deficiency. None of the patients had experienced any episodes of thrombosis. Additionally, the following observations were made: 1) Levels of polymorphonuclear (PMN)-elastase protein were markedly elevated in 6 of 6 patients and 10 of 11 parents tested, and levels were higher in homozygotes than in heterozygotes. 2) Hereditary factor XII deficiency was found in 3 of 6 patients tested. 3) C1-inhibitor was elevated in 2 of 4 patients, prekallikrein was elevated in 1 of 4 patients, and plasminogen activator inhibitor type 1 was elevated in 1 of 4 patients. Infusions of lys-plasminogen concentrate induced pronounced fibrinolytic activity as indicated by high levels of D-dimer, increases in plasmin-antiplasmin complex and decreases in polymorphonuclear elastase. C1-inhibitor, prekallikrein and PAI-1 normalized after repeated infusions of lys-plasminogen. In contrast to dysplasminogenemia, severe type I plasminogen deficiency might be seen as a problem of extravascular space, in particular of the mucous membranes, possibly triggered by mechanically induced or inflammatory lesions of the vessels supplying the tissue.

Adolescent↗
PubMed1991

Functional characterization of an abnormal factor XII molecule (F XII Bern).

An 18-year-old healthy woman was found to have cross-reacting material (CRM)-positive factor XII (F XII) deficiency, F XII clotting activity was less than 0.01 U/mL, whereas F XII antigen was 0.11 U/mL. An F XII inhibitor was excluded. To partially characterize the molecular defect of the abnormal F XII, immunologic and functional studies were performed on the proposita's plasma. The abnormal F XII was a single chain molecule with the same molecular weight (80 Kd) and the same isoelectric points (pl, 5.9 to 6.8) as normal F XII. Dextran sulfate activation of the proposita's plasma showed no proteolytic cleavage of F XII even after 120 minutes, whereas F XII in pooled normal plasma, diluted 1:10 with CRM-negative F XII-deficient plasma, was completely cleaved after 40 minutes. Adsorption to kaolin was identical for both abnormal and normal F XII. In the presence of dextran sulfate and exogenous plasma kallikrein, the abnormal F XII was cleaved with the same rate as normal F XII. However, kallikrein-cleaved abnormal F XII was not able to cleave factor XI and plasma prekallikrein, in contrast to activated normal F XII. Thus, these studies show that the functional defect of this abnormal F XII, denoted as F XII Bern, is due to the lack of protease activity of the kallikrein-cleaved molecule. Therefore, the structural defect is likely to be located in the light chain region of F XII, containing the enzymatic active site.

Adsorption↗
PubMed2000

A modified, optimized kinetic photometric assay for the determination of blood coagulation factor XIII activity in plasma.

BACKGROUND: Blood coagulation factor XIII (FXIII) is a zymogen that is transformed into an active transglutaminase by thrombin and Ca(2+). FXIII plays an essential role in fibrin stabilization and in the protection of fibrin from proteolytic degradation. No convenient method has been available for the measurement of FXIII activity in plasma. The aim of the present study was to improve and optimize a kinetic photometric FXIII assay originally developed in our laboratory. METHODS: In the assay, FXIII was activated by thrombin and Ca(2+). Fibrin polymerization was prevented by an inhibitory tetrapeptide. Glycine-ethyl ester and a glutamine residue of a synthetic dodecapeptide served as acyl acceptor and acyl donor transglutaminase substrates, respectively. The amount of ammonia released during the reaction was monitored using glutamate dehydrogenase and NADPH. RESULTS: The use of a new glutamine substrate and optimization of activator and substrate concentrations increased sensitivity. Substitution of NADPH for NADH and introduction of an appropriate blank eliminated systemic overestimation of FXIII activity. The recovery of FXIII was 96%, the assay was linear up to 470 U/L, the detection limit was 1 U/L, and the imprecision (CV) was <8% even at very low FXIII activities. A reference interval of 108-224 U/L (69-143%) was established. The results correlated well with results obtained by an immunoassay specific for plasma FXIII. CONCLUSIONS: The optimized FXIII assay is a simple, rapid method for the diagnosis of inherited or acquired FXIII deficiencies and increased FXIII concentrations. It can be easily adapted to clinical chemistry analyzers.

Adult↗
PubMedDate not supplied

Acquired and congenital clotting syndromes.

Although Virchow postulated 100 years ago that hypercoagulability states exist, it has only been in recent years that methods of documenting hypercoagulability have been developed. These clotting tendencies can be acquired or congenital. The common causes of acquired clotting tendencies include conditions which result in tissue and cellular damage, shock, transfusion reactions, and tissue necrosis. Certain drugs and drug reactions, and certain disease states which include blood dyscrasias and cancer are also associated with clotting problems. In certain diseases such as homocystinuria, hyperlipidemia, and lupus erythematosus, abnormal clotting tendencies may also develop. Important advances in the recognition of hypercoagulability have come with the documentation that congenital clotting abnormalities exist. Moreover, these abnormalities are proving to be more common than are congenital bleeding syndromes. Patients who appear to have spontaneous clotting manifestations and are under 40 years of age should be screened for one of these abnormalities. These congenital clotting tendencies can be classified as defects in thrombosis inhibitors, dysfibrinogenemias, or defects in fibrinolysis. The first thrombotic inhibitor defect recognized was antithrombin III deficiency which was reported in 1965. Subsequently, Protein C, Protein S, and Heparin cofactor II deficiencies have been recognized as contributing to thrombotic tendencies. Dysfibrinogenemias are relatively rare and most are associated with bleeding problems; however, 11% of the abnormal fibrinogens are associated with a clotting tendency. The reason appears to be that these fibrins are resistant to fibrinolysis. The most common defects which are associated with thrombotic tendencies appear, at the present time, to be due to defects in fibrinolysis. These include hypoplasminogenemia, decreases in plasminogen activator, increases in plasminogen activator inhibitor, and Factor XII deficiency.

Blood Coagulation Disorders↗
PubMed1990

FXII.

The plasma protein FXII (Hageman factor) has been shown to be linked with the plasma defence systems of coagulation, fibrinolysis, kallikrein-kinin and complement. It can be activated by surface contact activation and in solution. Surface contact activation is a complex phenomenon involving negatively charged surfaces, FXII, high molecular weight kininogen and plasma kallikrein. Fluid-phase activation can be effected by a variety of serine proteases. In both types of activation the FXII zymogen is converted to active enzymes. FXII levels in plasma are low or undetectable in both inherited deficiencies and in a variety of clinical conditions. FXII levels can also be elevated in some clinical conditions. Although discovered as a clotting protein FXII appears to play an important role in the kallikrein-kinin and fibrinolytic systems and also has effects on cells. Recent studies suggest that therapeutic blockade of activation of FXII can be of benefit in certain clinical conditions.

Animals↗
PubMed1986

Loss of the largest von Willebrand factor multimers from the plasma of patients with congenital cardiac defects.

We identified a consecutive series of 12 children with noncyanotic congenital cardiac lesions with loss of the largest plasma von Willebrand factor (vWF) multimers determined by SDS-agarose electrophoresis. Seven had previous histories of mucocutaneous hemorrhage; ten had a prolonged bleeding time. Analysis of the factor VIII molecular complex revealed that six patients had reduced vWF measured both immunologically (vW:Ag) and by ristocetin cofactor assay (vW:rist). All had normal or borderline normal factor VIII procoagulant (F VIII) concentrations. Three children had prolonged partial thromboplastin times due to concurrent factor XII deficiency; none had laboratory evidence of intravascular coagulation. Five of the children were restudied after surgical correction of their cardiac lesions. Four had normalization of vWF multimers; the fifth, whose vWF was abnormal postoperatively, had a residual pressure gradient across a previous pulmonary artery banding site. Multimeric abnormalities were not found in the parents of three patients. Thus some patients with noncyanotic congenital heart disease may have an acquired abnormality of vWF that is normalized with correction of the abnormal hemodynamic state.

Blood Coagulation↗
PubMed1991

Pseudopathologies of hemostasis and dental surgery.

Values of hemostasis tests are grossly abnormal in persons with factor XII deficiency, dysfibrinogenemia, the lupuslike anticoagulant, and pseudothrombocytopenia, yet these persons do not usually bleed spontaneously or even after surgery. We reviewed the records of 66 patients with laboratory diagnosis of one of the aforementioned abnormalities to determine whether they bled excessively after challenges to hemostasis such as dental extractions. Only three of them bled excessively, but two of these had other concomitant causes that could explain bleeding. Hence the dentist should not give up dental extractions or other surgical procedures when results of hemostasis tests are grossly abnormal, because these are not necessarily associated with abnormal hemostasis. Obviously, the correct interpretation of abnormal hemostasis values warrants close collaboration and reciprocal consultation between the dentist and the hematologist.

Adult↗