Clinical and Laboratory Validation of the 2nd International Standard of Low Molecular Weight Heparin (IS 2003-01/608) in the Anti-Xa, Anti-LIA Heptest and Prothrombinase Induced Clotting (PiCT) Tests.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4147-4147
Author(s):  
D. Hoppensteadt ◽  
W. Jeske ◽  
D. Fareed ◽  
F. Baltasar ◽  
J. M. Walenga ◽  
...  
Keyword(s):  
Molecular Weight ◽  
International Standards ◽  
Clinical Monitoring ◽  
Low Molecular Weight ◽  
Therapeutic Trial ◽  
Global Test ◽  
International Standard ◽  
Assay Methods ◽  
The Individual ◽  
Concentration Curves

Abstract Background: Because of the relative insensitivity of the global clot based assays such as the activated partial thromboplastin time (APTT), the low molecular weight heparins (LMWHs) are potency evaluated/optimized in the anti-Xa (AXa) and heptest. A new clot based assay namely, prothrombin induced clotting time (PiCT) is sensitive to the anticoagulant effects of LMWHs and related drugs. As the LMWHs are standardized using the anti-Xa methods, using the International Standards, this study was designed to cross validate the 2nd International Standard for LMWHs(NIBSC 01/608) in various assay methods. Methods: Commercially available LMWHs, Dalteparin (D), Enoxaparin (E), Tinzaparin (T) and the 1st International Standard (85/600) were crossed referenced against the 2nd International Standard (NIBSC 01/608) using an amidolytic AXa method. Each of these LMWHs were compared in the AXa, adjusted concentration range of 0–1.0 U/ml using the Heptest, AXa, AIIa and PiCT. In addition plasma samples from patients receiving a LMWH, E for therapeutic and interventional purposes were measured using various tests. Results: The AXa potency adjusted LMWHs (D, E, and T) and 1st International Standard provided superimposable concentration curves in the amidolytic AXa assays. However marked differences in the heptest and PiCT were noted. Major differences were noted in the AIIA levels, even between the two International standards. When patients samples (n=75) from a therapeutic trial (1.0 mg/kg BID/SC) were evaluated, assay based differences were further amplified. The amidolytic AXa assay consistently measured higher AXa levels. When the two standards were cross-referenced with one another in different assays, major differences were noted in the clot-based assays. Even in the AXa assay at equivalent AXa levels, differences were obvious. Conclusions: These results suggest that both of the International Standards of LMWH are valid for only the cross standardization of the AXa activities of LMWHs. If any of the other methods were used, significantly different results were obtained with each of the individual LMWHs. Thus, the 2nd International Standard should only be used for amidolytic AXa assay for potency referencing purposes. Moreover, the stated potency of the 2nd Internation Standard may need to be readjusted against the 1st Standard to obtain valid results. These standards are of limited value in the clinical monitoring of LMWHs. It is therefore proposed that each of the LMWHs should be cross referenced by its own standard and the clinical monitoring of these drugs should only be carried out utilizing the specific drug used in a given patient. The PiCT test offers a global test which is capable of monitoring the effects of all components of heparins regardless of their affinity to serpines. Moreover, the effect of TFPI released on clotting processes is also measured. Thus, the PiCT test provides a physiologically relevant anticoagulant index.

Standardization of Low Molecular Weight Heparins : A Collaborative Study

1985 ◽  
Vol 54 (03) ◽  
pp. 675-679 ◽  
Author(s):  
T W Barrowcliffe ◽  
A D Curtis ◽  
T P Tomlinson ◽  
A R Hubbard ◽  
E A Johnson ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Collaborative Study ◽  
Assay Method ◽  
Low Molecular Weight ◽  
Low Molecular Weight Heparins ◽  
International Standard ◽  
Assay Methods

SummaryA collaborative study was carried out, in which eight laboratories each assayed eight low molecular weight (LMW) heparins against the International Standard (IS) for heparin. APTT assays and three types of anti-Xa method were used. The results of this study showed that:1. LMW heparins cannot be validly assayed against the IS by APTT or anti-Xa methods.2. Potencies of LMW heparins vs. the IS differed considerably between the four types of assay method used and also between different laboratories using the same type of method.3. Adoption of a single LMW heparin standard would improve validity, improve inter-laboratory variation, and largely abolish the differences between the three types of anti-Xa method. However, since calibration of a LMW heparin standard against the IS would give potencies that differ widely by the different assay methods, a single assay method such as the anti-Xa amidolytic, plasma, would need to be chosen for this calibration.

An International Standard for Low Molecular Weight Heparin

1988 ◽  
Vol 60 (01) ◽  
pp. 001-007 ◽  
Author(s):  
T W Barrowcliffe ◽  
A D Curtis ◽  
E A Johnson ◽  
D P Thomas
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Collaborative Study ◽  
Low Molecular Weight ◽  
International Standard ◽  
Thrombin Inhibition ◽  
Interlaboratory Variability ◽  
Assay Methods ◽  
The Mean ◽  
International Collaborative Study

SummaryAn international collaborative study has been carried out with the aim of establishing an international standard for low molecular weight (LMW) heparin. Three preparations of LMW heparin were assayed against the International Standard for unfractionated heparin (UFH) by 25 laboratories in 13 countries, using nine different assay methods. The results confirmed previous findings of non-parallel assays, wide interlaboratory variability and differences between methods when LMW heparins are assayed against a UFH standard. Use of one of the LMW heparins as a standard for the other two gave parallel assays and much closer agreement between laboratories. The preparation in ampoules coded 85/600 was selected as likely to give the best agreement with the largest number of LMW heparins; potencies were assigned by taking the mean of all the anti-Xa assays, and the mean of the thrombin and APTT assays, to represent the two major groups of activities. Preparation 85/600 has been established by WHO as the 1st International Standard for LMW heparin, with potencies of 1,680 iu/ampoule by anti-Xa assays and 665 iu/ampoule by thrombin inhibition and APTT assays.

Molecular weight determines the frequency of delayed type hypersensitivity reactions to heparin and synthetic oligosaccharides

2005 ◽  
Vol 94 (12) ◽  
pp. 1265-1269 ◽  
Author(s):  
Susanne Alban ◽  
Roland Kaufmann ◽  
Edelgard Lindhoff-Last ◽  
Wolf-Henning Boehncke ◽  
Ralf J. Ludwig ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Heparin Therapy ◽  
Delayed Type Hypersensitivity ◽  
Published Data ◽  
Low Molecular Weight ◽  
Hypersensitivity Reactions ◽  
Type Iv ◽  
Total Data ◽  
The Individual

SummaryEczematous lesions, resulting from type IV sensitizations are well-known and relatively frequent cutaneous adverse effects of s.c. heparin therapy. If anticoagulation is further required intravenous heparin, heparinoids or lepirudin may be used as a substitute. However, these alternatives are not optimal in terms of practicability and/or safety-profiles. As molecular weight of different heparin preparations has repetitively been implied to determine the frequency of sensitization, we hypothesized, that due to its low molecular weight the pentasaccharide fondaparinux may provide a practicable and safe anticoagulant therapy in patients with delayed type hypersensitivity reactions (DTH) to heparin and other oligosaccharides. To test this concept, patients referred for diagnosis of cutaneous reactions after s.c. anticoagulant treatment underwent a series of in vivo skin allergyand challenge-tests with unfractionated heparin, a series of low molecular weight heparins (nadroparin, dalteparin, tinzaparin, enoxaparin and certoparin), the heparinoid danaparoid and the synthetic pentasaccharide fondaparinux. In total, data from twelve patients was evaluated. In accordance with previously published data, we report a high crossreactivity among heparins and heparinoids. In contrast – and in support of our initial hypothesis – sensitization towards the synthetic pentasaccharide fondaparinux was rarely observed. Plotting the cumulative incidence against the determined molecular weight of the individual anticoagulant preparations, shows that molecular weight generally is a key determinant of sensitization towards heparins and other oligosaccharides (r2=0.842, p=0.009). Hence, fondaparinux may be used as a therapeutic alternative in patients with cutaneous DTH relations towards heparin and other polysaccharides.

Effect of concomitant diseases on the hemostasis system in the perioperative period of non-cardiac surgery

2021 ◽  
Author(s):  
И.С. Пряхин ◽  
С.С. Мурашко ◽  
С.А. Бернс ◽  
И.Н. Пасечник
Keyword(s):  
Molecular Weight ◽  
Cardiac Surgery ◽  
Antithrombotic Therapy ◽  
Perioperative Period ◽  
Low Molecular Weight ◽  
Clinical Factors ◽  
Low Molecular Weight Heparins ◽  
Global Test ◽  
Thrombotic Risk ◽  
Increased Risk

В данном исследовании изучалось влияние клинических факторов и антитромботической терапии на свертывающую систему крови пациентов в периоперационном периоде. В исследование включено 80 пациентов, которым проводилось плановое некардиальное хирургическое вмешательство. Лабораторный контроль осуществлялся с использованием рутинных методов исследования гемостаза (АЧТВ, МНО) и глобального теста исследования гемостаза (тест тромбодинамики). Использование теста тромбодинамики в данном исследовании оказалось более чувствительным методом по сравнению с рутинными тестами и позволило выявить клинические факторы, ассоциированные с гиперкоагуляционными состояниями и снижением эффективности низкомолекулярных гепаринов в послеоперационном периоде: возраст старше 60 лет, фибрилляция предсердий, хроническая ишемическая болезнь сердца, стентирование коронарных артерий в анамнезе, предшествующий прием антитромботической терапии до оперативного вмешательства. У больных с тромбозом глубоких вен нижних конечностей отмечалась гиперкоагуляция в первые сутки после проведения операции по сравнению с остальными пациентами. Использование теста тромбодинамики за сутки до оперативного вмешательства позволило спрогнозировать увеличение объема интраоперационной кровопотери. Назначение периоперационной мост-терапии низкомолекулярными гепаринами у больных с высоким тромботическим риском достоверно ассоциировалось с увеличением трансфузии эритромассы практически в 2 раза по сравнению с остальными пациентами и было связано с повышением риска геморрагических осложнений. Результаты исследования показали, что тест тромбодинамики потенциально может быть применен в дальнейших исследованиях с целью персонификации ведения пациентов в периоперационном периоде при некардиальной хирургии, а также способен прогнозировать возникновение геморрагических и тромботических осложнений. This study examined the effect of clinical factors and antithrombotic therapy on the blood coagulation system of patients in the perioperative period. The study included 80 patients who underwent elective noncardiac surgery. Laboratory control of hemostasis was carried out using routine tests for studying hemostasis (APTT, INR) and a global test for hemostasis (thrombodynamics test). Usage of the thrombodynamics test in this study was more sensitive compared to routine tests and made it possible to identify clinical factors associated with hypercoagulable states and «decreasing in the effectiveness» of low molecular weight heparins in the postoperative period. These factors are: age over 60 years, chronic ischemic heart disease, a history of coronary artery stenting, prior antithrombotic therapy before surgery. Hypercoagulability was found on the first day after surgery in patients with deep vein thrombosis of the lower extremities compared to other patients. The use of a thrombodynamics test a day before surgery allowed to predict an increase of intraoperative blood loss volume. Perioperative bridge therapy with low molecular weight heparins in high thrombotic risk patients was significantly associated with an increase in packed red blood cells transfusion of almost two times compared with other patients and is associated with an increased risk of hemorrhagic complications. The results of the study showed that thrombodynamics test can potentially be used further with the aim of personalizing patients’ management in the non-cardiac surgery perioperative period. It also helps to predict the occurrence of hemorrhagic and thrombotic complications.

Thrombin Generation Is a Sensitive Measure of Low Molecular Weight Heparin Anticoagulant Activity.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1099-1099
Author(s):  
Alexander Gatt ◽  
Anne Riddell ◽  
Lesley Lanning ◽  
Saman Aghighi ◽  
Pamala Kanagasapathy ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Thrombin Generation ◽  
Conflicts Of Interest ◽  
Anticoagulant Activity ◽  
Coagulation Cascade ◽  
Low Molecular Weight ◽  
Acute Thrombosis ◽  
Coagulation Proteins ◽  
Risk Patients ◽  
The Individual

Abstract Abstract 1099 Current guidelines recommend monitoring of low molecular weight heparins (LMWHs) using the anti-Xa assay in high risk patients like those with renal impairment, pregnancy or overweight and in children. However, it is well accepted that this test does not accurately predict the anticoagulant effect of these drugs1. This is understandable since the various LMWHs available affect the coagulation cascade in different ways relative to their different molecular structure. Notoriously, the larger LMWHs like Tinzaparin have a higher anti-IIa to anti-Xa ratio that is not detected by the anti-Xa assay. We hypothesized that thrombin generation (TG) is a better, more sensitive way how to monitor LMWH anticoagulant activity since it is a measure of the interplay of all coagulation proteins. Blood samples from patients with acute thrombosis, pregnancy and other conditions and having LMWH monitoring were analysed using a chromogenic anti-Xa assay and a TG assay as per Hemker et al2 together with a chromogenic anti-IIa and FVIII clotting assay (FVIII:C). A tissue factor trigger of 10pM Innovin was used for the TG experiments. Patient samples were divided into 2 groups: those on Tinzaparin (n=45) or Enoxaparin (n=39). There was no difference between the FVIII:C levels of the Tinzaparin and Enoxaparin groups (mean 250 vs 327IU/ml P>0.05). A higher lower mean anti-Xa and a higher mean anti-IIa level was achieved with Tinzaparin (0.48 vs 0.63 U/ml P= >0.05 for anti-Xa and 0.3 vs 0.15U/ml P=0.005 for anti-IIa respectively). The endogenous thrombin potential (ETP) was significantly lower with Tinzaparin than Enoxaparin despite a higher anti-Xa (705 vs 1216nM.min P=0.006). Linear regression analysing TG with anti-Xa of the two LMWHs shows that 1.0U/ml antiXa activity for Enoxaparin is as potent as 0.7U/ml Tinzaparin in suppressing TG to similar levels. Significant inter-individual variation in TG suppression was noted with both LMWHs. This study demonstrates that anti-Xa results achieved for different LMWHs do not have the same anticoagulant significance. Using TG, we achieved similar therapeutic anti-Xa levels as achieved from the individual LMWH clinical trials3. It is clear that TG is a better test to predict LMWH anticoagulant activity. This needs to be proven in clinical studies. 1. Baglin T et al British Journal of Haematol. 2006; 133(1): 19–34. 2. Hemker HC et al Pathophysiol Haemost Thromb, 33, 4-15. Boneu B and de Moorloose P. Semin Thromb Hemost 2001; 27(5): 519–522. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Exploring the Critical Factors Limiting Polyaniline Biocompatibility

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 362 ◽  
Author(s):  
Věra Kašpárková ◽  
Petr Humpolíček ◽  
Jaroslav Stejskal ◽  
Zdenka Capáková ◽  
Patrycja Bober ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Flow Cytometry ◽  
Cell Death ◽  
Ammonium Persulfate ◽  
Low Molecular Weight ◽  
Synergic Effect ◽  
Critical Factors ◽  
Aniline Hydrochloride ◽  
Crucial Information ◽  
The Individual

Today, the application of polyaniline in biomedicine is widely discussed. However, information about impurities released from polyaniline and about the cytotoxicity of its precursors aniline, aniline hydrochloride, and ammonium persulfate are scarce. Therefore, cytotoxicity thresholds for the individual precursors and their combinations were determined (MTT assay) and the type of cell death caused by exposition to the precursors was identified using flow-cytometry. Tests on fibroblasts revealed higher cytotoxicity of ammonium persulfate than aniline hydrochloride. Thanks to the synergic effect, both monomers in combination enhanced their cytotoxicities compared with individual substances. Thereafter, cytotoxicity of polyaniline doped with different acids (sulfuric, nitric, phosphoric, hydrochloric, and methanesulfonic) was determined and correlated with impurities present in respective sample (HPLC). The lowest cytotoxicity showed polyaniline doped with phosphoric acid (followed by sulfuric, methanesulfonic, and nitric acid). Cytotoxicity of polyaniline was mainly attributed to the presence of residual ammonium persulfate and low-molecular-weight polar substances. This is crucial information with respect to the purification of polyaniline and production of its cytocompatible form.

scholarly journals Co-morditities of environmental diseases: A common cause

2014 ◽  
Vol 7 (3) ◽  
pp. 117-122 ◽  
Author(s):  
Harold I. Zeliger
Keyword(s):  
Molecular Weight ◽  
Chronically Ill ◽  
Low Molecular Weight ◽  
Common Cause ◽  
Global Pandemic ◽  
Co Morbidity ◽  
Environmental Disease ◽  
Vector Borne ◽  
Sequential Absorption ◽  
The Individual

ABSTRACT The global pandemic of non-vector borne environmental diseases may, in large part, be attributed to chronic exposures to ever increasing levels of exogenous lipophilic chemicals. These chemicals include persistent organic pollutants, semi-volatile compounds and low molecular weight hydrocarbons. Such chemicals facilitate the sequential absorption of otherwise not absorbed more toxic hydrophilic species that attack numerous body organs and systems, leading to environmental disease. Co-morbidities of noncommunicable environmental diseases are alarmingly high, with as many as half of all individuals chronically ill with two or more diseases. Co-morbidity is to be anticipated, since all of the causative chemicals identified have independently been shown to trigger the individual diseases.

Fixed Doses of Anticoagulants Cause Wide Variation of Thrombin Generation

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5012-5012
Author(s):  
Coenraad Hemker ◽  
Saartje Bloemen ◽  
Romy Kremers ◽  
Hilde Kelchtermans ◽  
Bas De Laat
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Standard Dose ◽  
Vitamin K Antagonists ◽  
Factor Xa ◽  
Target Range ◽  
Low Molecular Weight ◽  
Standard Dosage ◽  
Variance Table ◽  
The Individual

Abstract Current practice in the prevention of venous thromboembolism (VTE) is either controlled dosage of vitamin K antagonists (VKA) or standard dosage of a low molecular weight heparin (LMWH) or an orally administrated direct inhibitor of thrombin or factor Xa (DOACs). This is justified by clinical trials showing the non-inferiority of standard dosage to VKA treatment - disregarding that the latter could be improved upon. Whether standard dosage is optimal for the individual patient depends upon how well (s)he is represented by the "average" patient that meets the inclusion criteria of the trial. Here we show that in a set of normal plasmas the individual thrombin generating power (the endogenous thrombin potential: ETP), after spiking with a fixed concentration (~ IC50) of different anticoagulants show such a wide variation that, even when plasma levels would be identical, a considerable percentage of patients could be over- or under-anticoagulated. Consequently adapted doses must be considered if better results than those with VKA are our aim. We recall that the ETP is close to constant in the individual person but varies in the population with a broad log-normal distribution (CV 16%). The ETP is highly correlated to the risk of thrombosis: The relative risk of VTE in the upper quartile being 5 - 7 times higher than that in the lower one (Winckers K., et al., poster PO617, ISTH 2015, Toronto). Reducing the ETP is the common feature of all antithrombotic therapy. The desired range of reduction is not exactly known. In congenital bleeding disorders bleeding risks increase sharply at ETP below 33%. In monitoring VKA treatment an INR below 2, which corresponds to an ETP > 66% of normal, is generally considered inadequate. We therefore arbitrarily choose the range 33 - 66% of normal, as a target range (TR). Experimental: Individual plasmas from 60 normal healthy volunteers were spiked with a fixed amount of either unfractionated heparin (UFH), low molecular weight heparin (LMWH), antithrombin binding pentasaccharide (penta), DOAC acting on thrombin or DOAC acting on factor Xa. We found the residual ETP to be highly variable (table column 3), obviously because the variation in susceptibility to the inhibitor superimposes upon the natural variation. Using these CVs we calculated what % falls either above or below the target range. The total variance of the ETP under treatment is the combined effect of natural variance, the pharmacokinetic- and the pharmacodynamic -variance. Here we determined pharmacodynamic effects only and calculated the % of ETP values that would fall outside the target range A: if there would be no pharmacokinetic variance (table column 4 & 5) and B: If the pharmacokinetic variance would equal the pharmacodynamic variance (table column 6 & 7). It is seen that in any case over 15% of the population will be outside the target range and that in the more likely case that pharmacokinetic variation counts as much as pharmacodynamic variation does around half of all patients will be outside the safe range. This could be avoided by measuring the effect of a standard dose of anticoagulant on the ETP once and increasing the dose in those with an ETP > 66% and decreasing it in those with ETP < 33%. The present work is meant to provide the rationale for starting clinical studies on the actual variation of the ETP attained under standard dosage of different anticoagulants and the effects thereon of personalised dose adjustment. Table Table. Disclosures Hemker: Diagnostica Stago: Consultancy.

The Human Plasmin-Derived Light (B) Chain·Streptokinase Complex: A Second-Generation Thrombolytic Agent

1983 ◽  
Vol 50 (04) ◽  
pp. 787-791 ◽  
Author(s):  
K C Robbins ◽  
L Summaria ◽  
R C Wohl ◽  
W R Bell
Keyword(s):  
Molecular Weight ◽  
Thrombolytic Agent ◽  
Second Generation ◽  
Catalytic Efficiency ◽  
Low Molecular Weight ◽  
Kinetic Properties ◽  
Human Plasminogen ◽  
Assay Methods ◽  
Similar Kinetic ◽  
Activator Complex

SummarySpecific assay methods for the human plasmin-derived light (B) chain · streptokinase (B·SK) complex, in terms of both streptokinase (SK) and urokinase (UK) International Units, are described. The kinetic properties of various SK activator complexes with plasminogen, Val 442-plasmin, and the plasmin-derived light (B) chain were compared to SK in terms of their catalytic efficiencies and Lineweaver-Burk plots. Similar kinetic data, and Lineweaver-Burk plots, are described for both highly purified high-molecular weight UK and low-molecular weight UK, including different clinical UK preparations. The B·SK complex has the highest catalytic efficiency of all the activator species studied. The Lineweaver-Burk plots of each of the various activator species are “fingerprints” of the enzymatic character of the activator. The B-SK complex is more like UK than SK, as an activator, in activating non-human plasminogen species. The biological halflife of the B·SK complex, in a dog model, was determined to be about 4 hr which is longer than the biological half-life(s) of SK in the same animal model, namely 0.6 hr (47%) and 2.8 hr (53%). This new second-generation activator complex may prove to be a useful thrombolytic agent in the treatment of thromboembolic diseases.

Sign in / Sign up

Export Citation Format

Share Document