SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The control of plasma levels fibrinstabilizing factor (factor XII) by women with abruptio placentae early resulted evident values under mean values. The cause of factor deficiency is still unclear. Supposed connections must still cleared up.
Explore the source record for details and available documents.
Genetic defects of fibrinogen are caused by a broad spectrum of mutations in one of the three structural genes FGA, FGB and FGG. They result in complete or partial lack of plasma fibrinogen (a- or hypofibrinogenaemia) or in structural abnormalities affecting protein function (dysfibrinogenaemia). In contrast to afibrinogenaemia mainly caused by nonsense, frameshift, and splice site mutations resulting in substantially truncated polypeptide chains (mainly Aalpha), in hypo- and dysfibrinogenaemias missense mutations lead to the exchange of single amino acids as dominating underlying defect. In the cases with quantitative disorders, bleeding with various degrees of severity is generally observed. Dysfibrinogenaemia is associated with both bleeding or thrombosis or even a combination of haemorrhagic and thromboembolic symptoms. About one half of the dysfibrinogenaemic cases is clinically asymptomatic. The plasmatic factor XIII (FXIII) is a heterotetramer composed of two A and two B subunits encoded by two different genes. FXIII deficiency is associated with bleeding, wound dehiscence and recurrent spontaneous abortions. The most frequent form is caused by defects in the A subunit with a broad spectrum of underlying mutations. Defects of the B subunit are very rare and were molecularly elucidated in only a few cases.
Explore the source record for details and available documents.
BACKGROUND: Blood coagulation factor XIII (F-XIII) promotes cross-linking of fibrin during blood coagulation. Impaired clot stabilization in patients with genetic deficiencies of F-XIII is associated with marked pathologies of wound healing. METHODS: 60 rats given carbon tetrachloride underwent ileal anastomosis after which they received albumin (Alb animals) or F-XIII concentrate (F-XIII animals) immediately after surgery and daily thereafter until day 2 or 4 and were euthanized on day 3 or 5, respectively, or until day 5 and were euthanized on day 7, 10, or 21. We measured the plasma F-XIII activity and anastomotic tensile strength, followed by immunohistochemical localization of F-XIII subunit A within anastomoses. RESULTS: On day 3, there were no significant differences between Alb and F-XIII animals for plasma F-XIII activity and tensile strength, and both groups of animals showed little immunostaining for F-XIII on anastomoses. Plasma F-XIII activities did not differ between Alb and F-XIII animals on day 5 (115.8 +/- 16.8 vs. 137.3 +/- 14.9%). Although the tensile strength in both groups was increased compared with that of day 3, that in F-XIII animals (129.8 +/- 3.3 gf) was significantly higher than that in Alb animals (100.8 +/- 5.3 gf, p = 0.014). F-XIII animals showed de novo collagen fibers and intense immunoreactivity of F-XIII in the extracellular matrix around the anastomoses. Similar differences occurred on day 7 but not days 10 and 21. CONCLUSIONS: F-XIII concentrate may accelerate the early healing process of intestinal anastomosis because of the protein's accumulation in situ.
Experiments were performed to investigate whether proteins other than fibrin are substrates for activated fibrin-stabilizing factor (FSF, blood coagulation Factor XIII, plasma transglutaminase) in clotting whole plasma. Three fluorescently labeled polypeptides were identified in serum prepared by clotting normal, but not FSF-deficient, plasma in the presence of the fluorescent amine, N-(5-aminopentyl)-5-dimethyl-aminonaphthalene-1-sulfonamide (dansylcadaverine). The major labeled polypeptide had a Mr (estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate) of 1.6 times 10(5) and was found in the protein fraction precipitated by 33 to 50% saturated ammonium sulfate. The second had a Mr of 2.0 times 10(5), was found in the protein fraction insoluble in 33% saturated ammonium sulfate, and was precipitated by gamma-globulin directed against cold-insoluble globulin. The third had a Mr of 1.1 times 10(5) and was precipitated by 33 to 50% saturated ammonium sulfate. All three polypeptides were found in the first protein peak when labeled serum was chromatographed on Sephadex G-200. The immunoprecipitin arc containing alpha2-macroglobulin was fluorescent when labeled serum was analyzed by immunoelectrophoresis. These results indicate that alpha2-macroglubulin, cold-insoluble globulin, and an unidentified third protein with a subunit of Mr = 1.1 times 10(5) are transamidated by FSF in clotting plasma. The concentration of cold-insoluble globulin was decreased in serum formed at 37 degrees from normal, but not from FSF-deficient, plasma. The depletion of cold-insoluble globulin in normal serum was partially blocked by clotting in the presence of dansylcadaverine and completely blocked by clotting in the absence of calcium ions. Sera formed at 2 degrees from both normal and FSF-deficient plasma contained less cold-insoluble globulin than plasma. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate of clots formed at 2 degrees demonstrated cross-linking of cold-insoluble globulin to fibrin in the normal, but not the FSF-deficient, sample. The serum concentration of alpha2-macroglobulin was the same as the plasma concentration irrespective of the conditions of clotting. Thus, the experiments suggest that FSF catalyzes the cross-linking of cold-insoluble globulin (but not alpha2-macroglobulin) to fibrin in clotting plasma.
Explore the source record for details and available documents.
Hemorrhagic tendencies are frequently seen in the neonatal period. From the practical point of view, recognition of physiologic deficiencies of coagulation factors and hemostasis is essential, for the differential diagnosis of hemorrhagic syndromes and adequate treatment. Values of coagulation factors in the newborn and comparison of our results and the results of other authors are presented. It seems that there are no essential changes in hemostasis of term infant, but many coagulation factors exhibit deficient clotting activity as like vitamin K-dependent factors (II, VII, IX, X). Values of fibrinogen, F. XI, XII, XIII are decreased. Those factors which physiologically low in the term infant reach normal adult levels in a few weeks, with the exception of factors IX and XI which may require several months to reach normal levels. In the same time authors presented the results of coagulation factors in mothers during delivery and term infants, to explain the nature of the disorders. For the investigation of these physiological defects, screening tests can be used.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Hemostasis in humans and other animals is a complex process that controls blood loss after a vascular injury. Factor XIII (FXIII) stabilizes clots primarily by cross-linking fibrin, thus protecting a newly formed clot from fibrinolysis by plasmin. Congenital deficiencies in humans involving FXIII are associated with delayed bleeding and wound healing and severe spontaneous hemorrhaging. These symptoms can be alleviated by intravenous administration of enriched FXIII plasma fractions. Circulating plasma FXIII is found as a heterotetramer that dissociates in the presence of calcium and thrombin into an active dimer and 2 inactive monomers. The recombinant FXIII under investigation is the active dimer alone. A 3-compartment, nonlinear population pharmacokinetic model was implemented in NONMEM V and then used to analyze data from preclinical studies in cynomolgus monkeys. The model simultaneously describes endogenous production of dimer (0.622 microg kg(-1) hr(-1)) and monomer (12.1 microg kg(-1) hr(-1)), and the administration of recombinant dimer. The model incorporates the rate and extent of complexation of recombinant dimer with available endogenous monomer (6.59 mg(-1) kg hr(-1)) to form the heterotetramer. Half-lives for dimer, heterotetramer, and monomer (3.33 hours, 2.83 days, and 3.94 hours for A(2), A(2)B(2), and B, respectively) were estimated, along with their variability in the population studied.
The variations of dilute blood clot lysis time (DBCLT) in 103 diabetic patients were investigated in terms of insulin dependency, body weight, serum lipids and presence of diabetic vascular diseases. The results showed that DBCLT was significantly longer in the 34 overweight diabetic patients (437 +/- 68 min) than in the 69 diabetics at or below the ideal body weight (240 +/- 28 min) or in the 76 normalipidemic normal weight control subjects (253 +/- 12 min). DBCLT was also longer in the hypertrigliceridemic diabetic patients than in the normolipidemic ones. The mean lysis time was similar in diabetic patients with and without retinopathy. However, a higher level of fibrinolytic inhibitors was found in patients with diabetic small vessel disease. In vitro inhibition of plasma factor XIII by p-chlormercuribenzoate (PCMB) caused an acceleration of DBCLT and the differences between lysis time in the overweight diabetics and in the controls were attenuated. These results suggested that deficient thrombolysis is rather due to overweight and to disturbances of lipid metabolism than to diabets and/or its vascular complications and that enhanced fibrin crosslinking is at least partially responsible for delayed clot lysis.
The prevalence of antithrombin (AT) deficiency in 342 unselected Brazilian patients with venous thrombosis was 1.16%, which increased to 3% when only patients under the age of 50 or with a familial history of thrombosis were considered. In two patients, a clinical (contraceptive use) or genetic risk factor (factor V Leiden and C677T in the methylene tetrahydrofolate reductase gene [MTHFR]) was identified and corroborated the hypothesis that an interaction of factors accounted for the appearance of thrombosis. However, no risk factor other than AT deficiency was identified in one patient with an important clinical and family history of spontaneous thrombosis. Three mutations were identified in these patients: a G-->A transition in intron 5 at position +1 (5'-->3'), three base insertions corresponding to arginine at position 5383 in exon 3A, and a G-->A transition at 13328, corresponding to an Ala404Thr de novo mutation. The polymorphisms in the genes coding for coagulation factors XII and XIII and fibrinogen normally associated with an increased risk for venous thrombosis were not related to thrombosis in these patients. This is the first study in South America to assess the prevalence of AT deficiency and to report the molecular characterization of the mutations involved.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.