Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.6 (thromboplastin)
13,278 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A child with severe factor IX deficiency who underwent an open-heart operation using extracorporeal circulation is described. The factor IX level was normalized immediately before operation and at the end of cardiopulmonary bypass by infusing prothrombin complex concentrate and fresh frozen plasma. Partial thromboplastin time and factor IX serum levels were monitored for 20 days postoperatively and showed factor IX activity higher than 50%.
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PMID:Repair of ventricular septal defect and aortic regurgitation associated with severe hemophilia B. 372 24

Using standard one stage clotting assays the concentrations of factors II, VII, IX and X were determined in 37 patients stabilised on warfarin for between three months and 17 years. Contrary to popular belief, the concentrations were not equally depressed, with factor X the lowest, factor II at intermediate value, factors VII and IX the highest. Some 71% of the variance of the British corrected ratio (BCR) could be accounted for by measurement of the factors assayed. Analysis of this variance showed 91% of the explained variance attributable to factor II, 7% to factor VII, 1.6% to factor IX and 0.4% to factor X. With the sudden and recent withdrawal of human thromboplastin, investigation of the sensitivities of the animal thromboplastins to changes in vitamin K dependent factors in orally anticoagulated patients is needed to ensure that the potentially alarming falls in factors II and X in these patients are being adequately detected.
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PMID:Factor II, VII, IX and X concentrations in patients receiving long term warfarin. 381 77

The abilities of normal and three abnormal factor IXa molecules to activate factor X and to bind to phospholipid membranes have been compared to define the contributions of protein-lipid interactions and factor IXa light chain-heavy chain interactions to the functioning of this protein. The abnormal proteins studied had altered amino acid residues in their light chains. The heavy-chain regions, containing the active site serine and histidine residues, were normal in the abnormal proteins on the basis of titration by antithrombin III. The binding constants (Kd) for normal (N), variant [Chapel Hill (CH) and Alabama (AL)], and gamma-carboxyglutamic acid (Gla) modified (MOD) factors IX and IXa to phosphatidylserine (PS)/phosphatidylcholine (PC) small, unilamellar vesicles (SUV) were measured by 90 degrees light scattering. The Kd values for factor IXN binding were quite sensitive to the PS content of the membrane but less sensitive to Ca2+ concentrations between 0.5 and 10 mM. The zymogen and activated forms of both normal and abnormal factor IX bound with similar affinities to PS/PC (30/70) SUV. In the cases of factor IXaN and factor IXaAL, but not factor IXaCH or factor IXaMOD, irreversible changes in scattering intensity suggested protein-induced vesicle fusion. Since the activation peptide is not released from factor IXaCH, the normal interaction of factor IXa with a membrane must require the release of the activation peptide and the presence of intact Gla residues. The rate of factor X activation by normal and abnormal factor IXa was obtained by using a chromogenic substrate for factor Xa in the presence of PS/PC (30/70) SUV and 5 mM Ca2+.
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PMID:Comparison of lipid binding and kinetic properties of normal, variant, and gamma-carboxyglutamic acid modified human factor IX and factor IXa. 387 87

A 28 year old pregnant woman was referred for genetic counselling because of a bleeding tendency and a family history of hemophilia. The hemophilia patients had 0.02 units/ml of factor IX activity and a normal concentration of factor IX antigen. In addition they had a prolonged coagulation time with bovine thromboplastin and were therefore cases of hemophilia BM. At the age of six the patient was hospitalized because of prolonged bleeding after a tooth extraction. At the age of 20 and 24 she gave birth to healthy daughters. The first delivery was complicated by a serious bleeding seven days post partum whereas the second delivery was without complications. Factor IX activity when she was three months pregnant was 0.02-0.03 units/ml and the factor IX antigen concentration was normal. Coagulation time with bovine thromboplastin was prolonged. Delivery was again normal, and she had a daughter with carrier values of factor IX. Her mother also had carrier values whereas her father was normal. The patient's hemophilia BM was probably due to extreme Lyonization in a heterozygote.
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PMID:Hemophilia BM in a female. 398 11

The effects of heparin on the activation of blood coagulation factors IX and X in contact-activated plasma were determined in the present study. In the presence and absence of 0.5 U/mL heparin, the amounts of factor IX that were cleaved 30 minutes after the addition of calcium and phospholipid to plasma exposed to glass (ie, contact activated) were essentially identical. In the absence of heparin, however, the plasma clotting time was between three and four minutes, while in the presence of heparin, the clotting time was approximately 40 minutes. More factor IXa was inhibited by antithrombin III in the presence of heparin than in its absence, but factor IXa levels sufficient for factor X activation appeared to be present in the heparinized plasma. Neither an increase in factor Xa nor a decrease in factor X was detected, however, in heparinized plasma. We conclude that the step in the intrinsic pathway of coagulation that is inhibited in the presence of heparin is at the level of factor X activation.
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PMID:The anticoagulant mechanism of action of heparin in contact-activated plasma: inhibition of factor X activation. 399 71

A telescoped model of nephrotoxic nephritis in the rabbit, using guinea pig antiglomerular basement membrane IgG in rabbits preimmunized with guinea pig IgG, reproducibly induced crescentic nephritis. Procoagulant activity (PCA) was measured in sieve-isolated glomeruli that had been either sonicated or cultured for 48 hours. In both sonicated and cultured glomeruli PCA peaked on days 5 and 6. The time course for appearance of PCA corresponded precisely with the appearance of proteinaceous material containing fibrin in Bowman's space as measured by a light microscopic histologic scoring system and confirmed by immunofluorescence and electron microscopy. Glomerular PCA returned to baseline by days 9 and 10 in spite of progression of glomerular injury. PCA also appeared in urine. Urine PCA peaked on day 8 and persisted through day 12 when glomerular PCA had returned to baseline. Glomerular and urine PCA were characterized using human coagulation factor-deficient plasmas and antithromboplastin IgG. Both glomerular PCA and urine PCA were inhibited by antithromboplastin IgG, showing that thromboplastin (tissue factor) contributed to PCA. The PCA in glomerular sonicates was dependent on factor X, but independent of factor VII or Hageman factor, suggesting that factor VII was present. Following glomerular culture for 48 hours the PCA had changed and in some cases was dependent on Hageman factor, factor IX, and factor VII for full PCA expression. Urine PCA was uniformly Hageman factor dependent and sometimes independent of factors VII and X. No active thrombin was present. The forms of glomerular and urine PCA were, therefore, complex. They seemed to be primarily driven by thromboplastin but also appeared to require the presence of the intrinsic coagulation pathway for full expression of PCA.
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PMID:Procoagulant activity in glomeruli and urine of rabbits with nephrotoxic nephritis. 402 44

Three patients with Christmas disease whose plasma was shown to have a prolonged one-stage prothrombin time with ox brain thromboplastin have been investigated. These patients have an inhibitor for the reaction between factor X, factor VII, and ox brain extract. The abnormal constituent responsible for this inhibitor appears to be factor IX whuch is functionally inactive but antigenically indistinguishable from normal factor IX. It is proposed that patients might be classified into haemophilia B(+) for patients with this defect (Christmas disease(+)) and haemophilia B(-) (Christmas disease(-)) for patients who have classical Christmas disease.
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PMID:An investigation of three patients with Christmas disease due to an abnormal type of factor IX. 497 71

Deficiencies of factor VIII (in haemophilia) and factor IX (in Christmas disease) prolong the partial thromboplastin time. If normal plasma is treated with alumina, the factor VIII remains but the factor IX is removed and can subsequently be recovered by elution of the alumina. If a long partial thromboplastin time is found on investigating a male patient whose history suggests a life-long bleeding disorder, the plasma may be retested after adding either alumina-adsorbed normal plasma or eluate. If the patient's partial thromboplastin time is shortened (relative to the control) by adding adsorbed normal plasma the patient is likely to be a haemophiliac; but if it is shortened by adding eluate then he is likely to have Christmas disease. Practical details for carrying out these manoeuvres are given and experiments on the validity of the test described.
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PMID:Partial thromboplastin time test with kaolin: diagnosis of haemophilia and Christmas disease without natural reference plasmas. 560 76

Coagulation studies were carried out on 30 patients with chronic liver disease. The clotting defect was complex and involved factors V, VII, IX (Christmas factor), and prothrombin. Some patients showed a significant depression of factor IX in the presence of a normal one-stage prothrombin time. Thrombotest was found to be a good indicator of factor IX deficiency in this group of patients and may be of use as an additional liver function test. The screening of patients with liver disease for surgery or liver biopsy should assess the coagulation factors involved in both intrinsic and extrinsic thromboplastin generation.
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PMID:Coagulation factors in chronic liver disease. 577 51

A 38-year-old male with proven Takayasu's arteritis presented, in a routine investigation, with thrombocytopenia, prolonged whole blood clotting time and activated partial thromboplastin time. Further studies demonstrated low levels of factor IX caused by a circulating anticoagulant. Immunological studies revealed an IgG (with kappa chains predominance) nature of this. Corticoid therapy decreased but did not suppress the anticoagulant activity. Since similar coagulation abnormalities have been described in collagen diseases, this observation is in support of this etiology to be considered in Takayasu's arteritis.
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PMID:Anti-factor IX circulating anticoagulant and immune thrombocytopenia in a case of Takayasu's arteritis. 611 Nov 71


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