In vitro tests of the potential thrombogenicity of factor ix concentrates: Inhibition and characterisation studies of NAPTT, TGt50 and PF3 moieties

1980 ◽  
Vol 20 (5-6) ◽  
pp. 491-498 ◽  
Author(s):  
Chris Prowse ◽  
Duncan S. Pepper
Keyword(s):  
Factor Ix ◽  
In Vitro Tests

Comparison of High Purity Factor IX Concentrates and a Prothrombin Complex Concentrate in a Canine Model of Thrombogenicity

1991 ◽  
Vol 66 (05) ◽  
pp. 609-613 ◽  
Author(s):  
I R MacGregor ◽  
J M Ferguson ◽  
L F McLaughlin ◽  
T Burnouf ◽  
C V Prowse
Keyword(s):  
High Purity ◽  
Time Course ◽  
Prothrombin Complex Concentrate ◽  
Degradation Products ◽  
Canine Model ◽  
Factor Ix ◽  
In Vitro Tests ◽  
Albumin Infusion

SummaryA non-stasis canine model of thrombogenicity has been used to evaluate batches of high purity factor IX concentrates from 4 manufacturers and a conventional prothrombin complex concentrate (PCC). Platelets, activated partial thromboplastin time (APTT), fibrinogen, fibrin(ogen) degradation products and fibrinopeptide A (FPA) were monitored before and after infusion of concentrate. Changes in FPA were found to be the most sensitive and reproducible indicator of thrombogenicity after infusion of batches of the PCC at doses of between 60 and 180 IU/kg, with a dose related delayed increase in FPA occurring. Total FPA generated after 100-120 IU/kg of 3 batches of PCC over the 3 h time course was 9-12 times that generated after albumin infusion. In contrast the amounts of FPA generated after 200 IU/kg of the 4 high purity factor IX products were in all cases similar to albumin infusion. It was noted that some batches of high purity concentrates had short NAPTTs indicating that current in vitro tests for potential thrombogenicity may be misleading in predicting the effects of these concentrates in vivo.

A Comparison of the in Vitro and in Vivo Thrombogenic Activity of Factor IX Concentrates Using Stasis (Wessler) and Non-Stasis Rabbit Models

1980 ◽  
Vol 44 (02) ◽  
pp. 081-086 ◽  
Author(s):  
C V Prowse ◽  
A E Williams
Keyword(s):  
Platelet Rich Plasma ◽  
Thrombus Formation ◽  
Factor Ix ◽  
Coagulation System ◽  
In Vitro Tests ◽  
Clinical Use ◽  
Low Activity

SummaryThe thrombogenic effects of selected factor IX concentrates were evaluated in two rabbit models; the Wessler stasis model and a novel non-stasis model. Concentrates active in either the NAPTT or TGt50 in vitro tests of potential thrombogenicity, or both, caused thrombus formation in the Wessler technique and activation of the coagulation system in the non-stasis model. A concentrate with low activity in both in vitro tests did not have thrombogenic effects in vivo, at the chosen dose. Results in the non-stasis model suggested that the thrombogenic effects of factor IX concentrates may occur by at least two mechanisms. A concentrate prepared from platelet-rich plasma and a pyrogenic concentrate were also tested and found to have no thrombogenic effect in vivo.These studies justify the use of the NAPTT and TGt50 in vitro tests for the screening of factor IX concentrates prior to clinical use.

In Vitro Thrombogenicity Tests of Factor IX Concentrates

1979 ◽  
Vol 42 (05) ◽  
pp. 1355-1367 ◽  
Author(s):  
C V Prowse ◽  
A Chirnside ◽  
R A Elton
Keyword(s):  
Factor Viii ◽  
Partial Thromboplastin Time ◽  
Generation Time ◽  
Activated Partial Thromboplastin Time ◽  
Factor Ix ◽  
In Vitro Tests ◽  
Factor Viii Inhibitor ◽  
Factor Ixa ◽  
Viii Inhibitor

SummaryVarious factor IX concentrates have been examined in a number of in vitro tests of thrombogenicity. The results suggest that some tests are superfluous as in concentrates with activity in any of these tests activation is revealed by a combination of the non-activated partial thromboplastin time, the thrombin (or Xa) generation time and factor VIII inhibitor bypassing activity tests. Assay of individual coagulant enzymes revealed that most concentrates contained more factor IXa than Xa. However only a small number of concentrates, chiefly those that had been purposefully activated, contained appreciable amounts of either enzyme.

FACTOR IX CONCENTRATES ARE THROMBOGENIC AT HIGH DOSES IN DOGS

1987 ◽  
Author(s):  
J Ferguson ◽  
J Dawes ◽  
C V Prowse ◽  
P R Foster ◽  
P A Feldman ◽  
...  
Keyword(s):  
Platelet Count ◽  
Fibrinogen Level ◽  
Canine Model ◽  
Factor Ix ◽  
In Vitro Tests ◽  
Fibrinopeptide A ◽  
Blood Products ◽  
Elevated Plasma ◽  
High Doses

A canine model has recently been established to assess the potential thrombogenicity of intravenously infused blood products. Elevated plasma levels of fibrinopeptide A (FpA) were identified as the most sensitive indicator of a thrombogenic response, and this was the only parameter to change significantly when issued batches of factor IX (II + X) concentrate were infused at a dose of 100 iu/kg. After infusion of 200 iu/kg, however, plasma FpA concentrations and FDP titres rose, the APTT was prolonged, and the platelet count and fibrinogen level fell. At this dose, therefore, FIX concentrates which were not identified by in vitro tests as potentially thrombogenic induced a response when infused into dogs.A batch of FIX concentrate which failed the criteria for in vitro thrombogenicity and was therefore not issued for routine use was infused at 100 iu/kg. Plasma FpA levels rose as did the FDP titre, and fibrinogen concentrations fell, but the APTT was only slightly prolonged. The thrombogenic response to 200 iu/kg of issued FIX concentrate was at least as severe as that following infusion of 100 iu/kg of this rejected batch.Thus, there is a threshold dose of FIX concentrate above which a severe thrombogenic response can ensue, and the current in vitro tests may not be a reliable indicator of potential thrombogenicity when FIX concentrates are infused at high doses. This should be taken into account when administering unusually high doses, particularly to patients who may have reduced levels of circulating protease inhibitors.

Measurement of Activated Factor IX in Factor IX Concentrates: Correlation with In Vivo Thrombogenicity

1995 ◽  
Vol 73 (04) ◽  
pp. 675-679 ◽  
Author(s):  
Elaine Gray ◽  
Jill Tubbs ◽  
S Thomas ◽  
A Oates ◽  
M Boisclair ◽  
...  
Keyword(s):  
Significant Positive Correlation ◽  
Factor Ix ◽  
In Vitro Tests ◽  
Prothrombin Complex Concentrates ◽  
Thrombotic Risk ◽  
Chromogenic Assay ◽  
The Mean ◽  
Thrombogenic Potential

SummaryCurrent in vitro tests for thrombogenicity of FIX concentrates used for prothrombin complex concentrates (PCCs), are of little value when applied to high purity FIX (HP FIXs). In the present study, we have developed a chromogenic assay for activated FIX (FIXa) and evaluated its ability to predict in vivo thrombogenic potential of HP FIXs in a modified Wessler stasis model. Among the HP FIXs, only 1 out of 7 products had no detectable FIXa; this product also showed no in vivo thrombogenicity. In the other 6 products, FIXa content ranged from 0.15–1.2 U/1000 iu FIX, and all showed some evidence of in vivo thrombogenicity, with mean thrombus scores ranging from 0.25–4. There was a significant positive correlation (r = 0.55, p <0.02) between FIXa levels and in vivo thrombogenicity of HP FIXs. NAPTT data were not significantly correlated with the in vivo results and the TFCT also showed no direct correlation with the mean thrombus score. These results indicate that HP FIXs may still carry a small residual thrombotic risk and measurement of FIXa content of these products may be a better predictor of thrombogenicity than the current in vitro tests.

In Vitro Thrombogenicity Tests of Factor IX Concentrates. II: Effects of Phospholipids and Heparin

1979 ◽  
Vol 42 (05) ◽  
pp. 1368-1377 ◽  
Author(s):  
C V Prowse ◽  
M C Boffa ◽  
C Guthrie ◽  
D S Pepper
Keyword(s):  
Total Phospholipid ◽  
Factor Xa ◽  
Relative Effect ◽  
Exchange Chromatography ◽  
Factor Ix ◽  
In Vitro Tests ◽  
Low Levels ◽  
Recalcification Time ◽  
Generation Test

SummaryMeasurement of the total phospholipid (and that portion active in coagulation) in factor IX concentrates revealed no correlation with in vitro tests of potential thrombogenicity, except in the case of the recalcification time and the thrombin generation test which may detect coagulant phospholipid as well as the presence of thrombogenic enzymes. This is probably due to separation of the prothrombin complex proteins from most phospholipid during ion-exchange chromatography. Although low levels of phospholipid remain in the final product these are apparently insufficient to effect appreciable activation of factor IX concentrates despite low levels of antithrombin III.Two tests which measure the formation of thrombin and factor Xa after recalcification of concentrates were affected by the addition of exogenous phospholipid. However this is a relative effect such that differences are quantitative rather than qualitative.Heparin addition during production of factor IX concentrate was found to have only minor effects on the results of in vitro thrombogenicity tests of the final product. This was confirmed in the laboratory by incubation of unheparinised products with heparin for periods of up to 6 hr.

Modified Tests for Measuring the Thrombogenic Potential of Factor IX Concentrates.

1979 ◽  
Author(s):  
Sarah M. Middleton ◽  
Jessie T. Douglas ◽  
C.D. Forbes ◽  
C.R.M. Prentice
Keyword(s):  
Factor Xa ◽  
Activated Partial Thromboplastin Time ◽  
Factor Ix ◽  
Procoagulant Activity ◽  
In Vitro Tests ◽  
Factor V ◽  
Thrombogenic Potential ◽  
Sepharose 4B ◽  
Generation Test

In vitro tests for screening potential thrombogenicity of factor IX concentrates are unsatisfactory as it has been shown that the non-activated partial thromboplastin time (NAPTT) and the TGt50 (reflecting thrombin generation by the concentrate after recalcification} do not correlate with each other. We have modified the TGt50 by addition of optimum concentrations of factor V and phospholipid, and compared it with the NAPTT and factor Xa generation test using the chromogenic substrate S2222. The modified TGtSO correlates with both the NAPTT and the factor Xa generation test suggesting that these tests are measuring the same entity. Chromatography of concentrates on sepharose 4B indicates that the high MW void volume material has procoagulant activity as measured by the unmodified TGt50 whilst the retained volume he procoagulant activity as measured by the TGt50 and the NAPTT. When, however, phospholipid is added to the unmodified TG150 the activity of the high MW component is lost and only that of the retained volume is still present. The data suggests that the modified TGt50 and the NAPTT measure the same procoagulant activity in these concentrates.

scholarly journals Assessment of Potential Thrombogenicity in an Animal Model of a Triple Viral Inactivated Factor IX Concentrate Manufactured in Argentina

2021 ◽  
Vol 8 (5) ◽  
Author(s):  
Martinez MC ◽  
◽  
Rodriguez R ◽  
Marinsaldi A ◽  
Rodriguez GR ◽  
...  
Keyword(s):  
Animal Model ◽  
Animal Experiments ◽  
In Vitro Assay ◽  
Factor Ix ◽  
In Vitro Tests ◽  
Vitro Assay ◽  
Thrombotic Risk ◽  
Significant Difference ◽  
The Mean

The risk of thromboembolism with FIX replacement therapy remains a concern for hemophilic B patients. Previous studies from our laboratory demonstrated that the activated factor content of the FIX Plasma Derived (FIXpd) manufactured at UNC-Hemoderivados was negligible by in vitro assay. Despite this, we considered it important to conduct studies to assess the potential thrombogenic risk of our FIXpd concentrates using a modified stasis animal model. FIXpd were inject doses of 100 or 200 IU F IX kg-1 and some samples were supplemented with heparin (<0.5 of heparin/ IU FIX). Eight rats were tested at each dose level in the presence or absence of heparin, considering those samples with a thrombogenicity ≥2.0 as of potential thrombogenic risk. The mean scores ± SD 100 and 200 IU kg-1 in the presence or absence of heparin were 0.25±0.06 and 2.25±0.45 and 1.19±0.26 and 2.81±0.40, respectively. At both doses tested of FIXpd in the absence of heparin, there was no significant difference in mean scores (P<0.05). The encouraging data obtained from these animal experiments and results from in vitro tests, support the low thrombotic risk associated with the FIXpd concentrate manufactured in UNC Hemoderivados.

Anti-Diabetic Activity of a Mineraloid Isolate, in vitro and in Genetically Diabetic Mice

2011 ◽  
Vol 81 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Joel Deneau ◽  
Taufeeq Ahmed ◽  
Roger Blotsky ◽  
Krzysztof Bojanowski
Keyword(s):  
Dna Microarrays ◽  
Human Fibroblasts ◽  
Diabetic Animal ◽  
In Vitro Tests ◽  
Diabetic Mice ◽  
Fossil Material ◽  
Expression Of Genes ◽  
Enhanced Expression ◽  
Genetically Diabetic Mice

Type II diabetes is a metabolic disease mediated through multiple molecular pathways. Here, we report anti-diabetic effect of a standardized isolate from a fossil material - a mineraloid leonardite - in in vitro tests and in genetically diabetic mice. The mineraloid isolate stimulated mitochondrial metabolism in human fibroblasts and this stimulation correlated with enhanced expression of genes coding for mitochondrial proteins such as ATP synthases and ribosomal protein precursors, as measured by DNA microarrays. In the diabetic animal model, consumption of the Totala isolate resulted in decreased weight gain, blood glucose, and glycated hemoglobin. To our best knowledge, this is the first description ever of a fossil material having anti-diabetic activity in pre-clinical models.

Potentially Thrombogenic Materials in Factor IX Concentrates

1975 ◽  
Vol 33 (03) ◽  
pp. 617-631 ◽  
Author(s):  
H. S Kingdon ◽  
R. L Lundblad ◽  
J. J Veltkamp ◽  
D. L Aronson
Keyword(s):  
Human Plasma ◽  
Antithrombin Iii ◽  
Factor Ix ◽  
In Vitro Assays ◽  
Substantial Agreement ◽  
Coefficient Of Correlation

SummaryFactor IX concentrates manufactured from human plasma and intended for therapeutic infusion in man have been suspected for some time of being potentially thrombogenic. In the current studies, assays were carried out in vitro and in vivo for potentially thrombogenic materials. It was possible to rank the various materials tested according to the amount of thrombogenic material detected. For concentrates not containing heparin, there was substantial agreement between the in vivo and in vitro assays, with a coefficient of correlation of 0.77. There was no correlation between the assays for thrombogenicity and the antithrombin III content. We conclude that many presently available concentrates of Factor IX contain substantial amounts of potentially thrombogenic enzymes, and that this fact must be considered in arriving at the decision whether or not to use them therapeutically.

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