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PubMed1999

Polymerization of fetal fibrin and alterations in fibrin network characteristics during diabetic pregnancy.

The present study compares plasma fibrin network characteristics of fetal blood and that of normal and diabetic pregnant women. Plasma fibrinogen concentration, clotting curves, mass-length ratio of the fibrin fibers, gross permeability and tensile strength of the networks, have been measured. Plasma glucose and glycated hemoglobin are used as glycemic index in diabetic gestational women. The fetal plasma has a lower concentration of fibrin and exhibits delayed clotting, the networks are made up of thinner fibers, are more cross-linked, have lower permeability, and increased tensile strength than in normal adults. The tensile strength of the networks prepared from the plasma of diabetic gestational women are more highly crosslinked than those made from plasma of normal women of corresponding length of pregnancy. The fibrin fiber-thickness is increased during the first and second trimester but is significantly reduced during the third trimester in the diabetic gestational women. The gross permeability of the networks is significantly reduced during the second and third trimester in the diabetic gestational women. The SDS-PAGE shows characteristic pattern of alpha, beta, and gamma-polypeptides in both normal and diabetic gestational women.

Adult↗
PubMed1979

Fibrin membrane endowed with biological function. IV. Formation of cross-links between fibrinogen (or fibrin) and ribonuclease by transglutaminase.

Transglutaminase from guinea pig liver catalyzed the formation of cross-links between fibrinogen (or fibrin) and ribonuclease. Using transglutaminase, immoblized ribonuclease was prepared by two separate methods: (1) fibrinogen-ribonuclease conjugates formed by transglutaminase were treated with thrombin to make fibrin membrane bound covalently to the enzyme; (2) fibrin polymer formed from fibrinogen with thrombin was covalently bound to ribonuclease by transglutaminase to make fibrin-ribonuclease conjugates.

Animals↗
PubMed1998

Fibrin-rich and platelet-rich thrombus formation on neointima: recombinant tissue factor pathway inhibitor prevents fibrin formation and neointimal development following repeated balloon injury of rabbit aorta.

Thrombus formation and neointimal growth are the critical events in restenosis after balloon angioplasty. However, the responses of diseased vessels to injuries caused by balloon angioplasty have not been well examined. We investigated the thrombus formation and neointimal development following the balloon injury to the previously induced neointima in the rabbit aorta and the effects of recombinant tissue factor pathway inhibitor (rTFPI) on these responses. Rabbit thoracic aortas were subjected to injury with a Fogarty 4F balloon catheter at 1.75 atm (first injury), and 4 weeks later the same vessels were subjected to the second injury with a Swan-Ganz 5F balloon catheter at 1.4 atm (mild-injury group) or 1.8 atm (severe-injury group), and immediately after that a retrograde bolus injection of rTFPI (100 microg/kg body weight) or saline was performed into the injured segments via the central tube of the Swan-Ganz catheter. Twenty minutes after the second injury, the injured surfaces were covered with platelet-rich thrombi in the mild-injury group and with fibrin-rich thrombi in the severe-injury group. Damaged intimal smooth muscle cells, which were immunohistochemically positive for tissue factor (TF), were observed beneath the fibrin-rich thrombi. The neointima 4 weeks after the second injury was significantly thicker in the severe-injury group than in the mild-injury group. The bolus infusion of rTFPI markedly inhibited fibrin formation on the injured surfaces, and significantly reduced the neointimal development in the severe-injury group at 4 weeks after the second injury. These results indicate that TF-dependent coagulation pathway is primarily responsible for fibrin-rich thrombus formation and may play an important role in neointimal development following the balloon injury to the rabbit aortic neointima. Additionally the bolus administration of rTFPI to the injured vessels could prevent mural thrombus formation and neointimal growth after balloon angioplasty.

Animals↗
PubMed1992

Bone induction by composites of bioresorbable carriers and demineralized bone in rats: a comparative study of fibrin-collagen paste, fibrin sealant, and polyorthoester with gentamicin.

Host tissue response and heterotopic osteoinduction by composites of demineralized bone matrix and three different substances used as bioresorbable carriers implanted in the abdominal muscles were evaluated by strontium 85 uptake and histology 4 weeks postoperatively in 60 male Wistar rats. Both fibrin-collagen paste and fibrin sealant inhibited bone induction and produced a chronic inflammation; part of the fibrin-collagen paste was still present at 4 weeks. Polyorthoester with gentamicin was almost completely absorbed, induced minimal tissue reaction, and did not inhibit osteoinduction.

Absorption↗
PubMed2005

Different contribution of interleukin-6 and cortisol activity to total plasma fibrin concentration and to acute mental stress-induced fibrin formation.

Acute mental stress may contribute to atherosclerosis by affecting inflammation and coagulation; however, the crosstalk between inflammation and coagulation during stress has not been studied. In the present study, we investigated the association of plasma fibrinogen, plasma IL-6 (interleukin-6) and free salivary cortisol with the procoagulant marker D-dimer reflecting fibrin formation both over a 2-h period and in response to acute mental stress. Twenty-one male volunteers (mean age, 47+/-8 years) underwent the Trier Social Stress Test combining a 3-min preparation phase, a 5-min job interview and 5-min mental arithmetic test before an audience. IL-6, fibrinogen, D-dimer and cortisol were measured immediately before and after stress, and after 45 min and 105 min of recovery from stress. Two distinct areas under the curve were computed to obtain integrated measures of total protein activity over the entire 2-h period and of stress reactivity of proteins. IL-6 (P < 0.001), fibrinogen (P = 0.001), D-dimer (P = 0.021) and cortisol (P < 0.001) had all significantly changed across the four time points assessed, as determined by ANOVA. For the entire 2-h period, total fibrinogen activity (R2 = 0.33, P = 0.007) and total cortisol activity (DeltaR2 = 0.17, P = 0.034) explained 50% of the variance in total D-dimer activity. Stress-induced changes in fibrinogen (R2 = 0.47, P = 0.001) and IL-6 (DeltaR2 = 0.18, P = 0.008) together explained 65% of the variance in D-dimer reactivity to stress. Total fibrin formation was independently predicted by fibrinogen and hypothalamo-pituitary-adrenal activity. Pro-inflammatory and procoagulant changes with stress were associated. Aside from fibrinogen reactivity, IL-6 reactivity was an independent predictor of stress-induced fibrin formation.

Adult↗
PubMed1978

Ristocetin precipitation test: a new simple test for detection of fibrin monomer and fibrin degradation products.

The ristocetin precipitation test was designed as a simplified test to detect fibrin monomers and fibrinogen/fibrin degradation products (FPD/fdp). The ristocetin precipitation test is positive in plasma samples containing either fibrin monomer (greater than 5--10 microgram/ml) or early fdp (greater than 50--100 microgram/ml). The ristocetin precipitation test is negative in plasma with fibrinogen concentrations to 1,000 mg/dl or fibrinogen degradation products FDP) and late fdp to 400 microgram/ml. The ristocetin precipitation test is positive in plasmas collected from rabbits after the infusion of thrombin (2.7 u/kg) or thrombin and streptokinase (10,000 u/kg); the test is negative in plasmas from animals treated with streptokinase or saline solution alone. The ristocetin precipitation test is negative in normal human plasmas and plasmas from patients who have primary firbinogenolysis, but positive in plasmas from patients with disseminated intravascular coagulation. These results suggest that the restocetin precipitation test can be a useful test for the detection of plasma fibrin monomers and early fdp.

Animals↗
PubMed1987

[The role of D2-E2 centers of interdomain binding of fibrin monomer during fibrinogen co-polymerization with an NH2-terminal disulfide knot of fibrin].

Copolymerization of fibrinogen with desAB- and desA-fibrin NH2-terminal disulfide knots (tN-DSK and rN-DSK, respectively) caused by interdomain D-E-binding was compared. It was shown that only tN-DSK effectively produces with fibrinogen soluble and insoluble forms of the copolymer characterized by a constant stoichiometry which, in turn, reflects its regular structure. Fibrinogen and rN-DSK complexing is weakly expressed. No soluble complexes were identified. A small quantity of insoluble complexes formed had no constant stoichiometry which points to the variability of their structure. It is concluded that the formation of the regular polymer structure during fibrinogen and fibrin N-DSK complex formation requires the participation of two types of complementary centers, namely: D1-E1 and D2-E2. This conclusion was confirmed by disturbances in fibrinogen and tN-DSK copolymerization at pH 6.5, when the function of the E2-center was inhibited. The significance of these findings for the understanding of the mechanisms of two types of D-E center function during fibrin clotting is discussed.

Animals↗
PubMedDate not supplied

[Mechanism of functioning of specific sites of interdomain D-E binding of fibrin molecules: interaction of fibrinogen with the N-terminal disulfide node of fibrin].

The intermolecular noncovalent binding of complementary fibrin polymerization sites localized in fibrin domains D and E was investigated in the model system. In this system fibrinogen molecules represent the active D domains and the N-terminal disulphide knot of fibrin (N-DSK) represents the active E domain. Quantitative definition of insoluble fibrinogen and N-DSK copolymer and light scattering data of their mixtures before the appearance of visible precipitate show that complexing of these structures decreases with an increase of the temperature and ionic strength. The character of this dependence permits certain conclusions to be made on the functioning mechanism for two types of the D-E binding sites. These conclusions are based on an idea of their different affinity. The interdomain binding is primarily realized by D1-E1 sites which are characterized by a high affinity and work mainly on the basis of electrostatic forces. This binding directs the D2-E2 binding which is characterized by lower affinity and which determines the final degree of fibrinogen and N-DSK complexing. These sites function mainly by the H-binding.

Animals↗
PubMed1984

Fibrin-mediated vascular injury. Identification of fibrin peptides that mediate endothelial cell retraction.

The deposition of fibrin, a ubiquitous component of acute and chronic inflammatory reactions, has been implicated by a number of recent studies as playing an active role in inflammation. In particular, fibrin deposition has been implicated in the development of tissue edema. As the "gateway" through which intravascular-to-extravascular movement of fluid, nutrients, and cells must pass, the vascular endothelial cells play a crucial regulatory role in this process. In support of this concept, recent studies in this laboratory have demonstrated that endothelial cells retract not only in the presence of fibrin but also in the presence of low molecular weight cleavage products of fibrinogen. It was further shown that this reaction was 1) specific for both vascular and corneal endothelial cells, 2) nontoxic, and 3) completely reversible. The present work examined the physiochemical nature of these endothelial-cell reactive factors. It was demonstrated by the use of enzymatically derived and synthetic fibrinogen peptides, that the active soluble fibrinogen-derived factor was associated with the amino-terminal end of the B chain of fibrinogen. The active factor has been tentatively identified as the B beta peptides, which is a primary plasmin cleavage product of fibrinogen and contains the thrombin-generated fibrinopeptide B. It is thus suggested that soluble, endothelial-cell-reactive peptides are released during both fibrinogenesis and fibrinolysis and, as such, modulate endothelial cell functions in vivo.

Animals↗
PubMed1980

[Inhibition of fibrin assembly by fragment D and its dimer derived from fibrinogen and stabilized fibrin. Evidence for the two-step type of inhibition].

The influence of purified fragments D and DD on fibrin monomer polymerization has been studied. When applied separately, DD is less strong an inhibitor than D. An addition of small amounts of DD to the reaction mixtures containing D does not change the inhibitory effect, when the concentration of the latter fragment is low. At high concentrations of D the contribution of DD becomes more pronounced. Small amounts of D added to DD-containing systems strongly enhances the inhibition. These properties of the D--DD mixtures are unpredictable and puzzling; they contradict the generally accepted view that the specific inhibitors of fibrin polymerization, to which D and DD belong, act in a simple competitive way. The whole incomprehensible situation may be clarified in terms of a hypothesis on a two-step mechanism of inhibition. It is assumed that at the first (preliminary) step of the inhibitor effect DD is less competent than D, whereas at the second step DD possessing a high affinity for the fibrin monomer, functions as the most effective competitive inhibitor.

Animals↗
PubMed1981

The influence of fibrin stabilization and fibrinolysis on the fibrin-adhesive system. A clinical study using radioactively marked fibrinogen as a tracer.

In many fields of surgery the use of highly concentrated human fibrinogen, which forms a fibrin clot when thrombin is added, is gaining increasing importance for tissue adhesion. A number of experimental and clinical reports on fibrin sealing have been published during recent years. The question underlying our present investigations is as follows: What happens to the tissue adhesive after its application to a wound in clinical use, i.e., how much time is required for complete resorption of the seal due to fibrinolytic processes? Skin graftings of the face (required to close defects caused by the excision of basal or spinal cell carcinomas) were performed by glueing rhomboid flaps or full thickness skin grafts to the wounds with the tissue adhesive to which 125I-marked fibrinogen has been added. Activity counts were recorded daily and CPM were plotted versus time to obtain summation curves. The physiological processes of fibrin stabilization and fibrinolysis are extensively discussed as both factors influence the tissue adhesive and thus have to be accounted for in clinical practice.

Aged↗
PubMed2005

MBCP biphasic calcium phosphate granules and tissucol fibrin sealant in rabbit femoral defects: the effect of fibrin on bone ingrowth.

An ageing population implies an increase in bone and dental diseases, which are in turn a source of numerous handicaps. These pathologies are an expensive burden for the European health system. As no specific bioactive materials are efficient enough to cope with this burden, we have to develop an injectable, mouldable, self-hardening bone substitute to support bone tissue reconstruction and augmentation. New, highly bioactive and suitable biomaterials have been developed to replace bone grafts in orthopedic revision and maxillofacial surgery for bone augmentation. These mouldable, self-hardening materials are based on the association of MBCP Biphasic Calcium Phosphate Granules and Tissucol Fibrin Sealant. The in vivo evaluation of ingrowth in relation to the composite was made in an experiment on rabbits. The results indicate that in the presence of fibrin sealant, newly-formed bone developed at a small distance from the surface of the calcium phosphate ceramic. Two different bone apposition processes were identified. Without the fibrin component (MBCP group), bone rested directly on the surface of the granules. This observation is commonly described as osteoconduction in calcium phosphate materials. On the contrary, the presence of the fibrinogen component seemed to modify this standard osteoconduction phenomenon: the newly-formed bone essentially grew at a distance from the surface of the granules, on the fibrillar network, and could be considered as an inductive phenomenon for osteogenic cell differentiation from mesenchymal stem cells.

Animals↗
PubMed1987

Glycosylation of human fibrinogen and fibrin in vitro. Its consequences on the properties of fibrin(ogen).

As observed for many proteins, glucose has been shown to bind non enzymatically to fibrinogen and to fibrin. The in vitro degree of glycosylation depends upon the concentration of glucose added to fibrinogen and also on the incubation period. This glycosylation induces a decrease in fibrin lysis by plasmin. On the contrary, it does not influence either fibrinogen activity as cofactor in ADP-induced platelet aggregation or the binding of thrombin onto a clot. Despite the 4 day half life of fibrinogen, since clearance of fibrinogen is exponential, it is assumed that very small quantities of fibrinogen may remain for a long time in the circulation leading to the presence of a low level of a highly glycosylated form of fibrinogen. Consequently, poorly degradable fibrin might be derived from this highly glycosylated fibrinogen and thus be responsible for capillary occlusion and also for atherosclerotic complications in the diabetic patient.

Adenosine Diphosphate↗
PubMed1982

Adsorptive endocytosis of fibrin monomer by macrophages: evidence of a receptor for the amino terminus of the fibrin alpha chain.

Human fibrinogen and fibrin monomer were labeled with heme-octapeptide for cytochemical examination of their interaction with rabbit peritoneal macrophages in vitro. Upon short exposure to labeled fibrin monomer in solution with unlabeled fibrinogen, the cells became covered with surface-adsorbed monomer in nonaggregated form and having a characteristic trinodular shape. Within 30 min, the adsorbed monomer became fully internalized by vesicular uptake, with much of it being incorporated into lysosomal bodies. A concomitant loss of adsorptive capacity of the cell surface for uptake of more monomer accompanied the internalization. By contrast, labeled fibrinogen was not adsorbed by the macrophage surface. Some internalization of fibrinogen by passive fluid-phase pinocytosis was evident, but it was not accompanied by loss of absorptive capacity for fibrin monomer. The active uptake of monomer may have depended on binding to the amino terminus that is blocked by fibrinopeptide A in fibrinogen, because addition of synthetic peptide corresponding to the terminal Gly-Pro-Arg segment inhibited both the adsorption and the internalization of monomer.

Endocytosis↗
PubMed1999

The molecular weights, mass distribution, chain composition, and structure of soluble fibrin degradation products released from a fibrin clot perfused with plasmin.

We used a perfused clot system to study the degradation of cross-linked fibrin. Multiangle laser light scattering showed that plasmin-mediated cleavage caused the release of noncovalently associated fibrin degradation products (FDPs) with a weight-averaged molar mass (Mw) of approximately 6 x 10(6) g/mol. The Mw of FDPs is dependent on ionic strength, and the Mw observed at 0.15 M NaCl resulted from the self-association of FDPs having Mw of approximately 3.8 x 10(6) g/mol. Complete solubilization required the cleavage of approximately 25% of fragment D/fragment E connections, with 48% alpha-, 62% beta-, and 42% gamma-chains cleaved. These results showed that D-E cleavage cannot be explained by a random mechanism, implying cooperativity. Gel filtration and multiangle laser light scattering showed that FDPs range from 2.5 x 10(5) to 1 x 10(7) g/mol. In addition to fragment E, FDPs are composed of fragments ranging from 2 x 10(5) Da (D-dimer, or DD) to at least 2.3 x 10(6) Da (DX8D). FDP mass distribution is consistent with a model whereby FDPs bind to fibrin with affinities proportional to fragment mass. Root mean square radius analysis showed that small FDPs approximate rigid rods, but this relationship breaks down as FDPs size increases, suggesting that large FDPs possess significant flexibility.

Electrophoresis, Polyacrylamide Gel↗
PubMed1983

The structure of fibrinogen and fibrin: II. Architecture of the fibrin clot.

Our present low resolution model for fibrinogen based on electron microscopy and x-ray diffraction data has been described by Cohen et al. A unique aspect of the structural analysis of fibrous proteins is that the molecular packing in ordered arrays reflects biologically significant intermolecular interactions. We have shown that the orthogonal sheet microcrystals, which are closely related to fibrin, are made up of a highly regular arrangement of two-stranded protofibrils, and we have visualized aspects of both the substructure of the protofibrils as well as their packing to form the fibrin clot. By correlation of structural data with biochemical studies we have begun to identify certain functional regions of the fibrinogen model related to fibrin. Many aspects of fibrinogen's physiological activity remain to be related to its structure. As our present model is improved by higher resolution studies, we will see with increasing clarity molecular features critical for clot formation and fibrinolysis.

Computers↗
PubMedDate not supplied

Fibrin stabilization (factor XIII), fibrin structure and thrombosis.

Factor XIII (FXIII) is a zymogen that is converted into an active transglutaminase (FXIIIa) by the concerted action of thrombin and Ca2+. Its main task is to crosslink alpha-, and gamma-chains of fibrin and alpha2-plasmin inhibitor to fibrin. By this way FXIIIa strengthens fibrin and protects it from the prompt elimination by fibrinolytic system.The changes of FXIII level in thrombotic diseases are hardly explored and there are contradictory results concerning the protective effect of Val34Leu polymorphism against arterial or venous thrombosis. The results suggest that the thrombo-protective effect of Leu34 allele prevails only in certain genetic and/or environmental constellations.

Factor XIII↗
PubMed1993

Histomorphological evaluation of wound healing of rabbit oviduct after microsurgical reanastomosis with the use of autologous fibrin adhesive, human fibrin adhesive or poly-glycolic acid suture.

The morphology of the healing process of microsurgical reanastomosis of the rabbit oviduct with the use of fibrin adhesive, autologous and heterologous, and conventional sutures is described. Both oviducts in 48 rabbits were cut and reanastomosis were performed. The rabbits were killed at different intervals after the operations, ranging from 2 h to 28 days, and the anastomoses were evaluated by histomorphological examination. The autologous fibrin adhesive was absorbed after a week and an uncomplicated healing was observed. Heterologous fibrin adhesive caused a granulomatous inflammation interpreted as an immune reaction of the host to the foreign protein, and conventional suturing resulted in severe tissue damage with an intensive inflammatory reaction.

Animals↗