Atrase B, a novel metalloprotease with anti‐complement and anti‐coagulant activity, significantly delays discordant cardiac xenograft rejection

2020 ◽  
Vol 27 (5) ◽  
Author(s):  
Cheng Fu ◽  
Lei Shi ◽  
Xia Huang ◽  
Hao Feng ◽  
Xiaosheng Tan ◽  
...  
Keyword(s):  
Xenograft Rejection ◽  
Coagulant Activity

Non-Fasting Factor VII Coagulant Activity (FVII:C) Increased by High-Fat Diet

1994 ◽  
Vol 71 (06) ◽  
pp. 755-758 ◽  
Author(s):  
E M Bladbjerg ◽  
P Marckmann ◽  
B Sandström ◽  
J Jespersen
Keyword(s):  
High Fat Diet ◽  
Fat Content ◽  
Factor Vii ◽  
Amidolytic Activity ◽  
High Fat ◽  
Low Fat Diet ◽  
Increased Risk ◽  
Coagulant Activity ◽  
High Fat Diets ◽  
Fat Diets

SummaryPreliminary observations have suggested that non-fasting factor VII coagulant activity (FVII:C) may be related to the dietary fat content. To confirm this, we performed a randomised cross-over study. Seventeen young volunteers were served 2 controlled isoenergetic diets differing in fat content (20% or 50% of energy). The 2 diets were served on 2 consecutive days. Blood samples were collected at 8.00 h, 16.30 h and 19.30 h, and analysed for triglycerides, FVII coagulant activity using human (FVII:C) or bovine thromboplastin (FVII:Bt), and FVII amidolytic activity (FVIPAm). The ratio FVII:Bt/FVII:Am (a measure of FVII activation) increased from fasting levels on both diets, but most markedly on the high-fat diet. In contrast, FVII: Am (a measure of FVII protein) tended to decrease from fasting levels on both diets. FVII:C rose from fasting levels on the high-fat diet, but not on the low-fat diet. The findings suggest that high-fat diets increase non-fasting FVII:C, and consequently may be associated with increased risk of thrombosis.

The Endothelial Cell and the Factor VIII Bypassing Activity of Prothrombin Complex Concentrate

1988 ◽  
Vol 60 (02) ◽  
pp. 226-229 ◽  
Author(s):  
Jerome M Teitel ◽  
Hong-Yu Ni ◽  
John J Freedman ◽  
M Bernadette Garvey
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Factor Viii ◽  
Prothrombin Complex Concentrate ◽  
Vascular Endothelial Cells ◽  
Vascular Endothelial ◽  
Monolayer Cultures ◽  
Coagulant Activity ◽  
Time Courses ◽  
Privileged Site

SummarySome classical hemophiliacs have a paradoxical hemostatic response to prothrombin complex concentrate (PCC). We hypothesized that vascular endothelial cells (EC) may contribute to this “factor VIII bypassing activity”. When PCC were incubated with suspensions or monolayer cultures of EC, they acquired the ability to partially bypass the defect of factor VIII deficient plasma. This factor VIII bypassing activity distributed with EC and not with the supernatant PCC, and was not a general property of intravascular cells. The effect of PCC was even more dramatic on fixed EC monolayers, which became procoagulant after incubation with PCC. The time courses of association and dissociation of the PCC-derived factor VIII bypassing activity of fixed and viable EC monolayers were both rapid. We conclude that EC may provide a privileged site for sequestration of constituents of PCC which express coagulant activity and which bypass the abnormality of factor VIII deficient plasma.

Factor VII Clotting Assay: Influence of Different Thromboplastins and Factor VII-Deficient Plasmas

1991 ◽  
Vol 65 (02) ◽  
pp. 160-164 ◽  
Author(s):  
Marina Poggio ◽  
Armando Tripodi ◽  
Guglielmo Mariani ◽  
Pier Mannuccio Mannucci ◽  
Keyword(s):  
Heart Disease ◽  
Ischemic Heart Disease ◽  
Dose Response ◽  
Response Curve ◽  
Ischemic Heart ◽  
Factor Vii ◽  
Response Curves ◽  
Assay Sensitivity ◽  
Clinical Laboratories ◽  
Coagulant Activity

SummaryBeing a putative predictor of ischemic heart disease, the measurement of factor VII (FVTI) coagulant activity will be presumably requested to clinical laboratories with increasing frequency. To assess the influence on FVII assays of different thromboplastins and FVII-deficient plasmas we compared performances of all possible combinations of 5 thromboplastins and 6 deficient plasmas. The reproducibility of the clotting times of the dose-response curves for human and rabbit thromboplastins were acceptable (CV lower than 7%), whereas bovine thromboplastin had a higher CV. Reproducibility was very similar for all deficient plasmas when they were used in combination with a given thromboplastin. Responsiveness of the dose-response curve did not depend on the deficient plasma but rather on the thromboplastin: one rabbit thromboplastin was the least responsive, the bovine thromboplastin the most responsive, the human and the remaining two rabbit thromboplastins had intermediate responsiveness. Assay sensitivity to cold-activated FVII varied according to the thromboplastin: the bovine thromboplastin was the most sensitive, the human thromboplastin the least sensitive, of the three rabbit thromboplastins two were relatively sensitive, one was almost insensitive. In conclusion, our results indicate that thromboplastin rather than deficient plasma is the crucial factor in the standardization of FVII assay.

Antithrombin-mediated Inhibition of Factor Vlla-Tissue Factor Complex by the Synthetic Pentasaccharide Representing the Heparin Binding Site to Antithrombin

1996 ◽  
Vol 76 (01) ◽  
pp. 005-008 ◽  
Author(s):  
Jean Claude Lormeau ◽  
Jean Pascal Herault ◽  
Jean Marc Herbert
Keyword(s):  
Binding Site ◽  
Tissue Factor ◽  
Residual Activity ◽  
Coagulation Factors ◽  
Heparin Binding ◽  
Experimental Conditions ◽  
First Order ◽  
Heparin Binding Site ◽  
Coagulant Activity

SummaryWe examined the effect of the synthetic pentasaccharide representing the minimal binding site of heparin to antithrombin on the antithrombin-mediated inactivation of factor Vila bound to tissue factor. This effect was compared to the effect of unfractionated heparin. Using purified recombinant human coagulation factors and either a clotting or an amidolytic assay for the determination of the residual activity of factor Vila, we showed that the pentasaccharide was an efficient antithrombin-dependent inhibitor of the coagulant activity of tissue factor-factor Vila complex. In our experimental conditions, assuming a mean MW of 14,000 for heparin, the molar pseudo-first order rate constants for ATIII-mediated FVIIa inhibition by ATIII-binding heparin and by the synthetic pentasaccharide were found to be similar with respective values of 104,000 ± 10,500 min-1 and 112,000 ± 12,000 min-1 (mean ± s.e.m., n = 3)

Studies on the Haemostatic Defect in a Complicated Syndrome

1995 ◽  
Vol 74 (05) ◽  
pp. 1244-1251 ◽  
Author(s):  
H Stormorken ◽  
H Holmsen ◽  
R Sund ◽  
K S Sakariassen ◽  
T Hovig ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Bleeding Tendency ◽  
Clot Retraction ◽  
Abnormal Finding ◽  
Shear Rates ◽  
Perfusion Chamber ◽  
Coagulant Activity ◽  
5 Ht Uptake ◽  
And Storage

SummaryThe Stormorken syndrome is a multifacetted syndrome including a bleeding tendency. No deviations were found in the coagulation- or fibrinolytic systems. Platelet number was low normal, and size abnormal, whereas EM findings were unremarkable. Survival time was half normal. Clot retraction was initially rapid, but clearly decreased, whereas prothrombin consumption was also initially rapid, but complete. Membrane GP’s were normal, so was AA metabolism, PI-cycle, granule storage and secretion, and c-AMP function, whereas 5-HT uptake and storage was decreased. Optical platelet aggregation was low normal with all physiological agonists. The only clearly abnormal finding was that coagulant activity was present on non stimulated platelets at the same level as kaolin-stimulated normal platelets. This indicated a platelet abnormality which should lead to a thrombogenic, not to a haemorrhagic trait. This paradox may have its origin in rheology, because when challenged with in vivo shear rates in an ex vivo perfusion chamber, platelet cohesion was abnormally low. Further studies to better delineate the membrane abnormality are underway.

Postprandial Activation of Coagulant Factor VII by Long-chain Dietary Fatty Acids

1996 ◽  
Vol 76 (03) ◽  
pp. 369-371 ◽  
Author(s):  
T A B Sanders ◽  
G J Miller ◽  
Tamara de Grassi ◽  
Najat Yahia
Keyword(s):  
Fatty Acids ◽  
Dietary Fatty Acids ◽  
Factor Vii ◽  
Fat Intake ◽  
Long Chain Fatty Acids ◽  
Postprandial Lipaemia ◽  
Increased Risk ◽  
Coagulant Activity ◽  
Long Chain Triglycerides ◽  
Long Chain

SummaryFactor VII coagulant activity (FVIIc) is associated with an increased risk of fatal ischaemic heart disease (IHD). Several reports have suggested that dietary fat intake or hypertriglyceridaemia are associated with elevated levels of FVII. This study demonstrates that an intake of long-chain fatty acids sufficient to induce postprandial lipaemia in healthy subjects leads to a substantial elevation in both FVIIc and the concentration of FVII circulating in the activated form. Such an increase in FVIIc could not be induced by medium-chain triglycerides. These results suggest that the consumption of a sufficient amount of long-chain triglycerides to induce postprandial lipaemia induces the activation of FVII.

Dietary Changes in Fasting Levels of Factor VII Coagulant Activity (FVII: C) Are Accompanied by Changes in Factor VII Protein and other Vitamin K-dependent Proteins

1995 ◽  
Vol 73 (02) ◽  
pp. 239-242 ◽  
Author(s):  
E M Bladbjerg ◽  
T Tholstrup ◽  
P Marckmann ◽  
B Sandström ◽  
J Jespersen
Keyword(s):  
Fatty Acids ◽  
Vitamin K ◽  
Protein C ◽  
Saturated Fatty Acids ◽  
Factor Vii ◽  
Dietary Regimen ◽  
Blood Samples ◽  
Dietary Changes ◽  
Coagulant Activity ◽  
Before And After

SummaryThe mechanisms behind dietary effects on fasting coagulant activity of factor VII (FVII: C) are not clarified. In the present study of 15 young volunteers, two experimental diets differing in composition of saturated fatty acids (C18:0 [diet S] or C12:0 + C14:0 [diet ML]) were served for 3 weeks each. Fasting blood samples were collected before and after the dietary regimen and analysed for triglycerides, FVII:C, and protein concentrations of FVII, FII, FX, protein C, CRP, albumin, fibrinogen, and F1+2. FVII:C was significantly reduced on diet S compared with diet ML. This was accompanied by a decrease in FVII protein, F1+2 and the vitamin K-dependent proteins FII, FX, and protein C. In contrast, no changes were observed in triglycerides, FVII:C/FVII: Ag, albumin and CRP. Fibrinogen was increased on diet S compared with diet ML. Our findings suggest that the change in fasting FVII:C was part of a general change in concentrations of vitamin K-dependent proteins.

The Relation Between VIIIR:AG and VIII:C Studied with Two Antisera

1979 ◽  
Author(s):  
H. P. Muller ◽  
N. H. van Tilburg ◽  
R. M. Bertina ◽  
J. J. Veltkamp
Keyword(s):  
Molecular Weight ◽  
High Salt ◽  
Low Molecular Weight ◽  
Gel Chromatography ◽  
Specific Antibodies ◽  
Specific Effects ◽  
Normal Plasma ◽  
Coagulant Activity ◽  
Sterical Hindrance ◽  
Inhibitory Antibodies

FVIII was separated into low molecular weight FVIII (LMW FVIII) and high molecular weight FVIII (HMW FVIII) by gel chromatography in the presence of high salt concentration or by high salt elution of LMW FVIII from FVIII bound to anti HMW FVII-Sepharose. Specific antibodies were raised in rabbits against HMW FVIII and LMW FVIII. After removal of the contaminating anti HMW activities the rabbit anti LMW FVIII was still able to neutralize the FVIII coagulant activity of normal plasma and of IMW FVIII with canparable efficiency and it had no effect on the VIIIR:WF of FVIII in normal plasma or in HMW FVIII. Anti LMW FVIII does not bind to HMW FVIII and does not precipitate FVIII as tested by counter immunoelectrophoresis. Rabbit anti HMW FVIII precipitates FVIII in normal plasma, inhibits VIIIR:WF activity, while it has no effect on the FVIII coagulant activity of LMW FVIII. The coagulant activity of FVIII in normal plasma is slightly inhibited by anti HMW FVIII presumably by non-specific effects (sterical hindrance). It is concluded that inhibitory antibodies against VIII:C raised in rabbits recognize antigenic structures only present on LMW FVIII. Antibodies against HMW FVIII raised in rabbits appears to recognize structures only present on HMW FVIII.

The Effects of Age, Gene Source and Familial Severity on Factor VIII in Normals and Haemophilia Carriers: Analysis by Multiple Regression

1983 ◽  
Vol 50 (03) ◽  
pp. 722-725 ◽  
Author(s):  
Bruce M Duncan ◽  
Lynn J Tunbridge ◽  
John V Lloyd
Keyword(s):  
Factor Viii ◽  
Multiple Regression ◽  
Analysis Of Covariance ◽  
Severe Haemophilia ◽  
Factor Viii Related Antigen ◽  
Defective Gene ◽  
Coagulant Activity

SummaryThere are conflicting views on the effects of age, gene source and familial severity on levels of factor VIII in carriers of haemophilia. Different workers have found that factor VIII increases with age, is higher in paternal carriers, and is higher in carriers from families with more severe haemophilia. Other workers have disagreed with these findings. In this study we explored some of the causes of this conflict. We measured factor VIII related antigen and factor VIII coagulant activity on 40 normal females and 48 carriers, and analysed the results by multiple regression and analysis of covariance. Our results indicated that both factor VIII coagulant activity and factor VIII related antigen increased with age, but were unaffected by the familial severity of haemophilia or whether the defective gene came from the mother or the father. We found that the conflicting reports of previous authors were due to high inter-correlations of the studied variables.

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