scholarly journals Experimental Hemostasis in Normal Dogs and Dogs with Congenital Disorders of Blood Coagulation

Blood ◽  
1967 ◽  
Vol 30 (5) ◽  
pp. 636-668 ◽  
Author(s):  
T. HOVIG ◽  
H. C. ROWSELL ◽  
W. J. DODDS ◽  
L. JØRGENSEN ◽  
J. F. MUSTARD
Keyword(s):  
Factor Viii ◽  
Blood Coagulation ◽  
Bleeding Time ◽  
Light And Electron Microscopy ◽  
Factor Ix ◽  
Surrounding Tissue ◽  
Factor Vii ◽  
Congenital Defects

Abstract Hemostasis was examined after transection of vessels, 50-200 microns in diameter, both in normal dogs and in dogs with congenital defects of either factor VII, factor IX, or factor VIII. The formation of the hemostatic platelet plugs was observed by direct microscopy in vivo, and sections of the plugs were prepared for both light and electron microscopy 10 to 30 minutes after transection. Furthermore, the reaction of platelets from normal and abnormal dogs with adenosine diphosphate, collagen and thrombin was tested in vitro by a turbidimetric technic. In normal and factor VII deficient dogs the initial arrest of bleeding took place about 3 minutes after transection, and rebleeding was infrequently observed. Their platelet plugs were composed of densely packed platelets, anchored to the vascular and perivascular tissue and surrounded by a cap of fibrin. In factor IX deficient dogs there was no definite prolongation of the initial bleeding time, but rebleedings were frequent. In factor VIII deficient dogs the initial bleeding time was prolonged and the intensity of the bleeding had a wave-like characteristic. The plugs in the hemophilic dogs were larger than normal, were rich in channels, and had areas of loosely packed platelets and an incomplete fibrin cap. Treatment of factor IX deficient dogs with Dicumarol did not further impair hemostatic plug formation in the doses used. Treatment of factor VII deficient dogs with heparin, or factor IX deficient dogs with phenylbutazone, prolonged the bleeding time markedly, delayed the building up of the plug, and gave fragile, loosely packed plugs. Treatment of normal dogs with phenylbutazone did not alter the hemostatic process at the dosage used. In the in vitro studies, platelets from the dogs with congenital coagulation defects reacted normally with the aggregating stimuli. It is concluded that the initial platelet interaction wih the vessel wall and surrounding tissue is not dependent upon blood coagulation. An intact intrinsic pathway of coagulation is necessary for the stabilization of the hemostatic plug after it is formed.

The Natural Course of Defibrination Syndrome Caused by Echis Colorata Venom in Man

1974 ◽  
Vol 31 (03) ◽  
pp. 420-428 ◽  
Author(s):  
M Fainaru ◽  
S Eisenberg ◽  
N Manny ◽  
C Hershko
Keyword(s):  
Factor Viii ◽  
Blood Coagulation ◽  
Major Bleeding ◽  
Renal Damage ◽  
Specific Treatment ◽  
Natural Course ◽  
Factor V ◽  
Thrombocyte Count

SummaryThe natural course of defibrination syndrome caused by Echis colorata venom (ECV) in five patients is reported. All patients developed afibrinogenemia within six hours after the bite. Concomitantly a depression in factor V was recorded. Factor VIII and thrombocyte count in blood were normal in most patients. In the light of the known effects of ECV on blood coagulation in vivo and in vitro it is concluded that the afibrinogenemia is due to intravascular clotting.Four patients had transient renal damage, manifested by oliguria, azotemia, albuminuria and cylindruria, ascribed to microthrombi in the renal glomeruli.After the bite, the natural course was benign, no major bleeding was observed, and all signs of coagulopathy reverted to normal within 7 days. Therefore we recommend no specific treatment for this condition. In the case of heavily bleeding patients, administration of antiserum against ECV and/or heparin should be considered.

scholarly journals In Vitro Effects on Thrombin of Paris Saponins and In Vivo Hemostatic Activity Evaluation of Paris fargesii var. brevipetala

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1420 ◽  
Author(s):  
Feiyan Wen ◽  
Tiezhu Chen ◽  
Hongxiang Yin ◽  
Juan Lin ◽  
Hao Zhang
Keyword(s):  
Blood Coagulation ◽  
Bleeding Time ◽  
Blood Lipid ◽  
Coagulation Parameters ◽  
Thrombin Activity ◽  
Hemostatic Activity ◽  
In Vitro Effects ◽  
Lipid Parameters

The resource shortage of Rhizoma Paridis has never been effectively addressed, and the industry continues to search for alternative resources. The in vitro effects on thrombin of Paris saponins and in vivo hemostatic activity of Paris fargesii var. brevipetala (PF) were evaluated in this study. PF is considered to be an alternative source of Rhizoma Paridis (RP). The in vitro incubation experiment was designed to investigate the effects on thrombin activity of Paris saponin H (PS H) and saponin extract in PF. The bleeding time of mouse tail snipping was used to evaluate the in vivo hemostatic effects of Paris saponins. Also, in vivo changes in four blood coagulation parameters in rats after oral administration of different groups of Paris saponins were compared. The effects of Paris saponins on liver function and blood lipid parameters were examined in order to avoid drug-induced liver injury. Activity studies of thrombin after ultra-filtration centrifugation showed that Paris saponins were able to enhance thrombin activity. Ultra performance liquid chromatography mass spectrometry (UPLC-MS) analysis results of the substrates led us to speculate that there is a specific binding between Paris saponins and thrombin. PS H and Paris saponins in PF significantly shortened the bleeding time in mice. One pathway by which Paris saponins enhance in vivo blood coagulation is by increasing fibrinogen (FIB), among the four blood coagulation parameters in rats. At the same time, the effects on liver and blood lipid parameters were insignificant. P. fargesii var. brevipetala can be developed as an alternative medicinal source of Rhizoma Paridis.

A Non-Stasis Rabbit Model for the Detection of Factor IX Concentrate Thrombogenicity.

1979 ◽  
Author(s):  
C.V. Prowse ◽  
A.R. Williams
Keyword(s):  
Platelet Count ◽  
Factor Viii ◽  
Partial Thromboplastin Time ◽  
Rabbit Model ◽  
Factor Ix ◽  
In Vitro Activity ◽  
Blood Samples ◽  
Intravascular Coagulation

A method has been developed whereby aerial blood samples can be obtained from a rabbit over a period of four hours following infusion of potentially thrombogenic solutions. Infusion of 50 uAg thrombin over JO minutes produced intravascular coagulation for up to three hours after infusion as demonstrated by a decrease in factor VIII, increase in partial thromboplastin time and fibrin(ogen) degradation producta and a positive ethanol gelation teat. No change in fibrinogen, factor DC or platelet count was found. Saline infusion produced no change in any of these parameters.Infusion of a variety of factor IX concentrates at 100 u/kg shewed that those concentrates active in in vitro thrombogenicity teste produced a similar effect to thrombin in vivo and in addition may result in a drop in platelet count. Infesion of concentrates with low in vitro activity did not induce intravascular coagulation.

THE PRACTICAL VALUE OF THE IN VITRO FILTER BLEEDING TIME

1987 ◽  
Author(s):  
G P Salmon ◽  
J R O’Brien
Keyword(s):  
Factor Viii ◽  
Bleeding Time ◽  
Normal Range ◽  
Normal Test ◽  
Factor Viii Concentrates ◽  
Von Willebrand ◽  
Sample Coefficient Of Variation ◽  
Test Treatment

The in vivo bleeding time has many disadvantages, some of which are obviated by an in vitro filter bleeding time. Normal native or heparinized blood is forced at 40mmHg through a filter made of glass microfibres with tortuous capillary sized pores which retain particles over lOμ. It is found that with high shear platelet aggregation occurs and when about 200,000 platelets (or 70/O of platelets are retained the filter becomes blocked. The test takes about two minutes to perform. Three routine measurements are easily made. (1) The % platelets retained between 10-20 secs; (2) the rate of blocking, e.g. drops 10-20/drops 0-5; (3) the blocking time. The within sample coefficient of variation (c of v) was 9% ± 4, n = 6. The c of v within stable patients studied over six months was 20% ± 11, n = 20. The correlation between platelet retention and the skin bleeding time is good overall when von Willebrand (VW) patients are included (r = ™0.73, n = 52) but absent when both tests are within the normal range. This test is sensitive to R:ag values from 0-160 (r = 0.62,n = 52) but poor within the VW and within normal groups. It is also abnormal in some patients with low platelet counts. Atherosclero-tics and diabetics have a normal test. Treatment of VW patients with DDAVP or with cryoprecipitate usually normalises this test. In one VW patient neither substance corrected this test and he bled. The test is thus useful in monitoring in vitro and in vivo the efficiency of various factor VIII concentrates to stop bleeding in VW disease. In vitro it is abnormal in the presence of many “membrane-active” drugs. Different drugs also have different effects on the retention of white cells; so it could be useful as a pharmacological screen. Thus it has uses as a quick and easy clinical screen for many forms of platelet-dependent haemostatic defects. It could also be used by the pharmaceutical industry and by producers of factor VIII concentrates.

scholarly journals Specific factor VIII-related antigen fragmentation: an in vivo and in vitro phenomenon

Blood ◽  
1982 ◽  
Vol 60 (4) ◽  
pp. 930-939 ◽  
Author(s):  
RR Montgomery ◽  
J Johnson
Keyword(s):  
Factor Viii ◽  
Bleeding Time ◽  
Antigenic Determinants ◽  
Specific Factor ◽  
Crossed Immunoelectrophoresis ◽  
Agarose Electrophoresis ◽  
Factor Viii Concentrates

Abstract Factor VIII concentrates have been shown to have reduced ability to correct the bleeding time defect in von Willebrand's disease and to have abnormal mobility of their VIIIR:Ag on crossed immunoelectrophoresis. This report concerns the partial characterization of a fragment of VIIIR:Ag that lacks some of the normal antigenic determinants present on VIIIR:Ag. It is present in commercial factor VIII concentrates, but not in cryoprecipitate, and is recovered from the plasma of hemophilic patients who have been infused with these concentrates. The fragment is also produced during disseminated intravascular coagulation. Although it has a similar mobility on SDS agarose electrophoresis to the smallest multimer of VIIIR:Ag, they are not immunologically identical.

scholarly journals A mutated factor X activatable by thrombin corrects bleedings in vivo in a rabbit model of antibody-induced hemophilia A

Haematologica ◽  
2019 ◽  
Vol 105 (9) ◽  
pp. 2335-2340
Author(s):  
Toufik Abache ◽  
Alexandre Fontayne ◽  
Dominique Grenier ◽  
Emilie Jacque ◽  
Alain Longue ◽  
...  
Keyword(s):  
Factor Viii ◽  
Hemophilia A ◽  
Factor Viia ◽  
Rabbit Model ◽  
Coagulation Factor ◽  
Factor Ix ◽  
Factor X ◽  
Factor Viiia

Rendering coagulation factor X sensitive to thrombin was proposed as a strategy that can bypass the need for factor VIII. In this paper, this non-replacement strategy was evaluated in vitro and in vivo in its ability to correct factor VIII but also factor IX, X and XI deficiencies. A novel modified factor X, named Actiten, was generated and produced in the HEK293F cell line. The molecule possesses the required post-translational modifications, partially keeps its ability to be activated by RVV-X, factor VIIa/tissue factor, factor VIIIa/factor IXa and acquires the ability to be activated by thrombin. The potency of the molecule was evaluated in respective deficient plasmas or hemophilia A plasmas, for some with inhibitors. Actiten corrects dose dependently all the assayed deficient plasmas. It is able to normalize the thrombin generation at 20 μg/mL showing however an increased lagtime. It was then assayed in a rabbit antibody-induced model of hemophilia A where, in contrast to recombinant factor X wild-type, it normalized the bleeding time and the loss of hemoglobin. No sign of thrombogenicity was observed and the generation of activated factor X was controlled by the anticoagulation pathway in all performed coagulation assays. This data indicates that Actiten may be considered as a possible non replacement factor to treat hemophilia's with the advantage of being a zymogen correcting bleedings only when needed.

scholarly journals Measurement of basal levels of factor VIIa in hemophilia A and B patients [see comments]

Blood ◽  
1992 ◽  
Vol 80 (1) ◽  
pp. 25-28 ◽  
Author(s):  
P Wildgoose ◽  
Y Nemerson ◽  
LL Hansen ◽  
FE Nielsen ◽  
S Glazer ◽  
...  
Keyword(s):  
Factor Viii ◽  
Factor Viia ◽  
Factor Ix ◽  
Factor Vii ◽  
Specificity And Sensitivity ◽  
Normal Individuals ◽  
Plasma Factor ◽  
Coagulation Assay ◽  
Relationship Of

Previous results, presented in abstract form, indicate that replacement of thromboplastin with a mixture of phospholipid and truncated soluble tissue factor apoprotein results in a coagulation assay that can directly measure plasma factor VIIa levels without interference from zymogen factor VII (Atherosclerosis Thromb 11:1544a, 1991 [abstr]). We have exploited the specificity and sensitivity of such a factor VIIa specific coagulation assay to directly assess the in vivo relationship of factor VIII and factor IX on the production of factor VIIa levels under nonthrombotic and nonstimulatory conditions. Normal individuals (n = 20) were found to possess an average circulating factor VIIa level corresponding to 4.34 +/- 1.57 ng/mL, or approximately 1% of their total factor VII antigen. Severe factor VIII deficient patients (n = 13) possessed a slightly lower but statistically significant (P less than .01) decrease in their basal factor VIIa levels (2.69 +/- 1.52 ng/mL), corresponding to approximately 60% of that observed in normal individuals. On the other hand, severe factor IX deficient patients (n = 7) were found to possess even lower levels of factor VIIa corresponding to 0.33 +/- 0.15 ng/mL, or less than 10% of that observed in normal individuals. Measurement of total factor VII antigen levels shows that the variation in basal factor VIIa levels stems from differences in the degree of factor VII activation as opposed to differences in factor VII antigen levels. Our present data are consistent with the hypothesis that factor IXa is the principal in vivo activator of factor VII under basal conditions.

Protein Inhibitor of Coagulation Factor Xa (PifXa): A New Protein-Based Specific Factor Xa Inhibitor Is An Effective, Reversible Inhibitor of Blood Coagulation.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1095-1095
Author(s):  
Mette Sondrup Andersen ◽  
Aage Kristian Olsen Alstrup ◽  
Julie Kirstine Andersen ◽  
Søren Risom Kristensen ◽  
Kåre Lehmann Nielsen
Keyword(s):  
Blood Coagulation ◽  
Bleeding Time ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Coagulation Cascade ◽  
Specific Factor ◽  
Low Molecular Weight ◽  
University Patents

Abstract Abstract 1095 Heparin was discovered in 1916 and put into clinical trials in 1935. Despite advent of several anticoagulants during the last 75 years, heparin still remains the most widely used anticoagulant. None the less, several drawbacks of heparin exist i) it is difficult to determine the correct dosage, ii) heparins binds many different targets in humans, iii) side effects such as Heparin Induced Thrombocytopenia (HIT) is known (Hirsh J et al, Chest 2001). Consequently, intense emphasis have been put on finding new and improved inhibitory agents towards specific factors in the blood coagulation. Especially factor Xa (fXa) is considered an interesting target for inhibitors due to its central place in the coagulation cascade (Gross PL and Weitz, JI, Clinical Pharmacology and therapeutics 2009). Here we present a novel direct specific inhibitor of fXa, PifXa (protein inhibitor of coagulation factor Xa), which has been isolated from potato tubers. The inhibitor of the legume Kunitz type protein family was able to inhibit the activity of fXa using a mixed mode of inhibition with an apparent Ki of 2.5 nM, as determined using a low molecular weight substrate. Noteworthy, no inhibition of thrombin could be detected. Furthermore, the effect of the inhibitor could be detected using the activated partial thromboplastin time (aPTT) assay, which suggests that PifXa is not only capable of inhibiting free fXa but also complex/clot-bound fXa. Other known specific fXa inhibitors such as the pentasaccharide fondaparinux (Arixtra, GlaxoSmithKline) and low molecular weight heparin (LMWH) give rise to little or no effect in the aPTT assay. This observation has been attributed to the fact that these inhibitors only inhibit free fXa (Hirsh J et al, Chest 2001). PifXa was capable of significantly prolonging the tail bleeding time, but did not increase the bleeding amount significantly compared to the control in in vivo experiments conducted in rats. Hence, PifXa is highly specific towards the blood coagulation cascade, but do not interfere with the platelet plug formation in contrast to heparin, that can interfere with the thrombin induced platelet activation (Day, J et al, J of Cardiothoracic and Vascular Anesthesia 2004). Indeed, inhibition of activation of the platelets by PifXa could not be detected in in vitro experiments using platelet aggreometry. Furthermore, PifXa given in combination with the anti-platelet drug acetylsalicylic acid increased both the bleeding time and amount in the in vivo rat experiment significantly, demonstrating an additive effect of PifXa and the antiplatelet drug. The combined effect exceeded that of both heparin and fondaparinux. In contrast to other specific factor Xa inhibitors, the effect of PifXa, being a protein, can be fully reversed by addition of a specific polyclonal antibody. That this is in fact possible was demonstrated in vitro. The specificity of the inhibitor combined with the possibility to reverse the effect makes PifXa an interesting candidate drug during cardio pulmonary bypass where the general inconvenient requirement for IV administration of protein drugs is tolerable, a large dose of anticoagulants in a limited period of time is necessary, and thus administration of an antidote to reverse the effect at the end of the procedure is desired. Disclosures: Andersen: Aalborg University: Patents & Royalties. Nielsen:Aalborg University: Patents & Royalties.

A Distinction between the Role of Precursor and Activated Forms of Clotting Factors in the Genesis of Stasis Thrombi

1967 ◽  
Vol 18 (01/02) ◽  
pp. 012-023 ◽  
Author(s):  
S Wessler ◽  
E. T Yin ◽  
L. W Gaston ◽  
Iona Nicol
Keyword(s):  
Human Serum ◽  
Factor Ix ◽  
In Vivo Studies ◽  
Factor Vii ◽  
Factor X ◽  
Clotting Factors ◽  
Insight Into

Summary1. In vivo studies in rabbits have shown that the liver diminishes the thrombo-genicity of infused human serum.2. In vitro rabbit liver perfusions with human serum have demonstrated the loss of serum thrombogenicity within 5 min after the onset of the perfusion. Associated with this loss of thrombotic capacity is a marked decrease in the activation product (AP) and labile factor IX (PPA) activity in the infused serum.3. The liver appears to have the capacity to discriminate between circulating activated clotting activities such as AP and PPA and inactive procoagulants such as stable or genuine factor IX, factor VII and factor X. The latter are not cleared from the circulation by the liver.4. These studies provide some insight into the mechanism whereby circulating activated clotting activities and retarded blood flow predispose to thrombosis.

The Effects of Leguminous Seed Extracts on Blood Coagulation

1962 ◽  
Vol 08 (02) ◽  
pp. 256-269
Author(s):  
R. J Speer ◽  
J. L Porter
Keyword(s):  
Factor Viii ◽  
Prothrombin Time ◽  
Blood Coagulation ◽  
Factor Ix ◽  
Factor Vii ◽  
Clot Lysis ◽  
Factor V ◽  
Leguminous Seed ◽  
Recalcification Time ◽  
Clot Time

SummaryThe saline extracts of one hundred leguminous seed were screened for their effect on blood coagulation by the following tests: thrombin clot time, recalcification time, Quick prothrombin time, clot lysis and clot retraction. Nineteen of these extracts, when reacted with normal plasma, gave a prolonged clot time in at least one of two tests: recalcification time and Quick prothrombin time. The eight which gave a prolonged Quick prothrombin time were tested for inhibition in the following assay systems: Factor V, factor VII-complex, and prothrombin. All nineteen, including the seventeen which prolonged the re-calcification time and the two which did not, were tested for their inhibitory action in the following assay systems: Factor VIII, factor IX, and plasma thromboplastin antecedent.The inhibition of prothrombin, factor V, and factor VII-complex was mild and not specific for any of these factors. Factor V activity was depressed more than the other two. By contrast, the inhibition of factor VIII, factor IX, and plasma thromboplastin antecedent was very strong and demonstrated a relatively high degree of specificity.

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