Inactivation of Factor XIa in Vivo: Studies in Chimpanzees and in Humans

1996 ◽  
Vol 76 (04) ◽  
pp. 549-555 ◽  
Author(s):  
Walter A Wuillemin ◽  
C Erik Hack ◽  
Wim K Bleeker ◽  
Bart J Biemond ◽  
Marcel Levi ◽  
...  
Keyword(s):  
Antithrombin Iii ◽  
Life Time ◽  
In Vivo Studies ◽  
Clinical Samples ◽  
Plasma Samples ◽  
C1 Inhibitor ◽  
Elimination Kinetics ◽  
Factor Xia ◽  
Best Parameter

SummaryC1-inhibitor (C1Inh), antithrombin III (ATIII), α1-antitrypsin (a1AT), and α2-antiplasmin (a2AP) are known inhibitors of factor XIa (FXIa). However, their precise contribution to FXIa inactivation in vivo is not known. We investigated FXIa inactivation in chimpanzees and assessed the contribution of these inhibitors to FXIa inactivation in patients with presumed FXI activation.Chimpanzees were infused with FXIa and the various FXIa-FXIa inhibitor complexes formed were measured. Most of FXIa was complexed to C1Inh (68%), followed by a2AP (13%), a1AT (10%), and ATIII (9%). Analysis of the plasma elimination kinetics revealed a half-life time of clearance (t1/2) for the FXIa-FXIa inhibitor complexes of 95 to 104 min, except for FXIa-a1AT, which had a t1/2 of 349 min. Due to this long t1/2, FXIa-a1AT complexes were predicted to show the highest levels in plasma samples from patients with activation of FXI. This was indeed shown in patients with disseminated intravascular coagulation, recent myocardial infarction or unstable angina pectoris. We conclude from this study that in vivo C1Inh is the predominant inhibitor of FXIa, but that FXIa-a1 AT complexes due to their relatively long t1/2 may be the best parameter to assess FXI activation in clinical samples.

scholarly journals In Vitro Characterization of Rabbit Thrombin, Antithrombin III, and Thrombin-Antithrombin III Complex, and Determination of Their Survival Times in Vivo

1977 ◽  
Author(s):  
Christine N. Vogel ◽  
Kingdon S. Henry ◽  
Roger L. Lundblad
Keyword(s):  
Gel Electrophoresis ◽  
Half Life ◽  
Antithrombin Iii ◽  
Specific Activity ◽  
Sodium Dodecyl ◽  
In Vivo Studies ◽  
Survival Times ◽  
At Iii

Our intention is to study the interaction of rabbit thrombin with antithrombin III (AT-III) in vitro and in vivo. After activation of crude prothrombin with tissue thromboplastin and CaCl2, thrombin was purified and showed two species of thrombin with molecular weights of 36,000 and 39,000 daltons as determined by sodium dodecyl sulfate discontinuous gel electrophoresis. Rabbit AT-III was purified using a heparin agarose column and had a molecular weight of 55,000 daltons. The inhibition of thrombin by AT-III was followed by fibrinogen clotting assays and an AT-III-thrombin complex was observed on gel electrophoresis. For the in vivo studies both thrombin and AT-III were radiolabelled with Na125i using the solid state lactoperoxidase method and retained 99% of the pre-iodinated specific activity. Radiolabelled thrombin and a radiolabelled AT-III-thrombin complex were injected into different rabbits. The rate of removal of both was very similar with a half-life of approximately 9 hours. When radiolabelled AT-III was injected, the half-life was approximately 60 hours. Since the disappearance rate of thrombin more closely approximates that of the preformed AT-III-thrombin complex and is clearly shorter than the turnover rate of AT-III, the possibility is raised that thrombin combines in vivo with a native inhibitor such as AT-III and may in fact be removed from the circulation as a complex rather than as a native molecule.

The Control Of Antithrombotic Prophylaxis And Therapy: A Pro-Coagulant Effect Of Heparin

1981 ◽  
Author(s):  
E Szwarcer ◽  
R Giuliani ◽  
E Martinez Aquino
Keyword(s):  
Blood Coagulation ◽  
Antithrombin Iii ◽  
Fixed Time ◽  
In Vitro Studies ◽  
In Vivo Studies ◽  
Clotting Factors ◽  
Platelet Poor Plasma ◽  
Normal Platelet

For studying heparin effect on blood coagulation and on inhibitors, the drug was added at increasing amounts to a normal platelet poor plasma (PPP), and to plasmas of patients with variable amounts of clotting factors (cirrhotic, pregnant, etc) -IN VITRO STUDIES-, and infused to the same individuals -IN VIVO STUDIES-. Modifications on two clotting assays (KCCT-TT) were compared to heparin potentiating effect on AntiXa (Denson & Bonnar tech).When studied IN VITRO, the sensibility of KCCT, TT, and AntiXa techniques for heparin measurement was similar. IN VIVO, an apparently greater sensibility using AntiXa technique was observed.For determining if this phenomena was related to a specific enhanced potentiating effect of the inhibitor against Xa, exerted by heparin IN VIVO, experiences were repeated IN VITRO and IN VIVO, measuring heparin effect on KCCT, TT, and on the inhibitor, studied against Xa and thrombin. A personal technique was used for the measurement of Antithrombin III heparin potentiating effect, using diluted platelet poor test plasma, heated (56°C 15’) and incubated with thrombin during a fixed time, and reading residual thrombin on citrated human PPP. IN VITRO, all techniques were similar in their ability to show heparin presence.IN VIVO, the potentiating effect of heparin on the inhibitor, measured against Xa or thrombin, was greater than the changes obtained on KCCT or TT.So, AntiXa-Antithrombin III techniques seem to be more sensitive for heparin measurement IN VIVO.This “dissociation” of results in between the potentiating effect on the inhibitor, that is not simultaneously exerted on global coagulation, is interpreted as a heparin pro-coagulant effect, exerted by the drug IN VIVO.

scholarly journals Activity and Concentration of Antithrombin III in Plasma and Serum

1977 ◽  
Author(s):  
L. Róka ◽  
H. Bleyl
Keyword(s):  
Antithrombin Iii ◽  
Specific Activity ◽  
Simultaneous Occurrence ◽  
Single Individual ◽  
Chromogenic Substrate ◽  
Plasma Samples ◽  
Specific Activities ◽  
Antithrombin Iii Activity ◽  
Heparin Affinity

The concentration and activity of antithrombin III contained in plasma and serum of a single individual were compared with each other. The concentration of antithrombin III was determined by means of the rockett technique according to Laurell, antithrombin activity was measured by thrombin neutralization, residual thrombin activity was quantified using the chromogenic substrate Chromozym TH. The patients’ plasmas examined could be divided into different groups according to their antithrombin III specific activity. Most of the samples contained about 34 U/mg, the specific activities of two other groups were about 20 u/mg and 15 U/mg respectively. Only 3 samples contained more than 45 U/mg. In plasma samples with low specific antithrombin III activity the simultaneous occurrence of free antithrombin and an antithrombin-thrombin complex formed in vivo has been demonstrated by means of the two-dimensional Immunoelectrophoresis with heparin added to the agarose-gel medium. (Sas et al., 1975). The antithrombin-thrombin complex could be separated from free antithrombin by adsorption to a heparin-agarose column and fractionated elution, using the different heparin affinity of complex-bound and free antithrombin.

Plasma elimination kinetics for factor VII are independent of its activation to factor VIIa and complex formation with plasma inhibitors

2009 ◽  
Vol 101 (05) ◽  
pp. 818-826 ◽  
Author(s):  
Torben Elm ◽  
Mirella Ezban ◽  
Thomas Krogh ◽  
Ditte Karpf ◽  
Anne Steinø ◽  
...  
Keyword(s):  
Complex Formation ◽  
Antithrombin Iii ◽  
Factor Viia ◽  
Factor Vii ◽  
Elimination Kinetics ◽  
Inhibitor Complex ◽  
Α2 Macroglobulin ◽  
Clearance Mechanism ◽  
Deficient Mice

SummaryThe mechanism for the elimination of factor VII (FVII) from the circulation is unknown, just as it is unclear how activation of FVII to FVIIa and subsequent complex formation with antithrombin III (AT) or α2-macroglobulin (α2M) affects clearance. The possibility that the clearance mechanism involves activation and inhibitor complex formation as obligatory intermediate reactions is examined in this study. Human and murine sera were spiked with human FVIIa in the absence and presence of heparin and analysed for complex formation. Complex formation in vivo was studied after intravenous injection of 125I-VIIa in mice; and the pharmacokinetics (PK) of human and murine FVIIa was studied in normal mice. Furthermore, comparative PK studies were performed with FVII, FVIIa, active site blocked FVIIa and a preformed FVIIa-AT complex in normal and α2M-deficient mice. The data demonstrated that FVIIa-AT complexes and to a much lesser extent FVIIa-α2M-complexes accumulated in vivo after FVIIa administration. FVIIa-AT accounted for about 50% of total FVIIa antigen left in the circulation after 3 hours. All FVII derivatives studied including FVII, FVIIa and FVIIa-AT were cleared with similar rates suggesting an elimination kinetics which is unaffected by FVII activation and subsequent inactivation by plasma inhibitors.

scholarly journals PHARMACOKINETIC PROFILE AND INCURRED ESOMEPRAZOLE SAMPLE STABILITY IN PLASMA USING HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY - PHOTODIODE ARRAY

2019 ◽  
pp. 214-219
Author(s):  
YAHDIANA HARAHAP ◽  
AHMAD FARIS ◽  
SUNARSIH .
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Pharmacokinetic Profile ◽  
Clinical Samples ◽  
Plasma Samples ◽  
Elimination Phase ◽  
Sample Stability ◽  
Photodiode Array

Objective: Esomeprazole (ESO) is one of the proton-pump inhibitors and is used to treat gastroesophageal reflux. It is sensitive to low pH, heat,moisture, and oxidation, which often means that ESO in clinical samples is degraded at the time of storage, affecting analysis results. This study aimedto analyze the in vivo stability of ESO in subjects’ plasma samples by testing the incurred sample stability (ISS) of ESO in plasma following 7, 14, and28 days of storage at two concentrations close to Cmax and one concentration in the elimination phase.Methods: Samples were analyzed using high-performance liquid chromatography with a C18 column with detection at 300 nm using a photodiodearray detector. Lansoprazole was used as an internal standard.Results: The ESO pharmacokinetics profile in the plasma samples yielded the values of Cmax 704.57–1425.85 ng/mL; tmax is 2.25 h; and AUC0-t is2444 ng.h/mL. ISS testing of plasma samples values were 6.50%, 5.73%, and 4.57% on first Cmax concentration; 3.55%, 4.84%, and 3.68% on 2nd Cmaxconcentration; and 4.04%, 4.80%, and 4.98% on elimination phase concentration.Conclusion: ISS testing results of plasma samples from six healthy subjects who were administered doses of 40 mg of ESO stored for 28 days showedthat it fulfilled the acceptance criteria (<20%) of the 2011 EMEA Bioanalytical Guidelines with a %diff value in all incurred samples of 6.5%.

STUDIES ON THE ANTICOAGULANT AND ANTITHROMBOTIC ACTIONS OF DERMATANS AND THEIR SULFATED DERIVATIVES

1987 ◽  
Author(s):  
D Hoppensteadt ◽  
A Kumar ◽  
J Fareed ◽  
J Mardigian
Keyword(s):  
Antithrombin Iii ◽  
Femoral Vein ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Protease Inhibition ◽  
Thrombosis Model ◽  
Antithrombotic Effects ◽  
Activated Prothrombin Complex Concentrates

Non-antithrombin III mediated effects such as interaction with heparin cofactor II, modulation of endothelium and polymorphonuclear leukocytes contribute to the overall antithrombotic effects of glycosaminoglycans. In order to study the role of these dermatans, we investigated their in vitro anticoagulant effects using the clot based (PT, APTT, TT, and Heptest), antiprotease (anti IIa and anti Xa) and Thromboplastin C activated fibrinopeptide A generation test. The in vivo antithrombotic actions were investigated, against activated and non activated prothrombin complex concentrates, and in combination with Russells viper venom in jugular and femoral vein stasis thrombosis models (rabbit). The dermatans studied consisted of a standard dermatan of porcine intestinal origin and four sulfated dermatans with varying degrees of sulfation. All of the dermatans studied showed weak anticoagulant effects on the routinely performed clot based assays. Marked variability was seen on the protease inhibition (anti Xa and anti IIa) assays. In the in vivo studies all dermatans studied showed varying degrees of antithrombotic actions against various thrombogenic agents in a modified stasis thrombosis model. Sulfation appeared to produce stronger anticoagulant effects as determined by in vitro assays, whereas the intravenous antithrombotic actions of native dermatan were stronger than sulfated derivatives. This data suggests that dermatans produce their antithrombotic actions via non-antithrombin III mediated pathways. Furthermore, in vitro testing methods are of limited value in the evaluation of the biologic actions of dermatans and their derivatives.

scholarly journals Systematic analyses reveal long non-coding RNA (PTAF)-mediated promotion of EMT and invasion-metastasis in serous ovarian cancer

2018 ◽  
Vol 17 (1) ◽  
Author(s):  
Haihai Liang ◽  
Xiaoguang Zhao ◽  
Chengyu Wang ◽  
Jian Sun ◽  
Yingzhun Chen ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Expression Profiles ◽  
In Vivo Studies ◽  
Clinical Samples ◽  
Orthotopic Mouse Model ◽  
Protein Coding ◽  
Mesenchymal Transition ◽  
Protein Coding Genes

Abstract Background A deeper mechanistic understanding of epithelial-to-mesenchymal transition (EMT) regulation is needed to improve current anti-metastasis strategies in ovarian cancer (OvCa). This study was designed to investigate the role of lncRNAs in EMT regulation during process of invasion-metastasis in serous OvCa to improve current anti-metastasis strategies for OvCa. Methods We systematically analyzes high-throughput gene expression profiles of both lncRNAs and protein-coding genes in OvCa samples with integrated epithelial (iE) subtype and integrated mesenchymal (iM) subtype labels. Mouse models, cytobiology, molecular biology assays and clinical samples were performed to elucidate the function and underlying mechanisms of lncRNA PTAF-mediated promotion of EMT and invasion-metastasis in serous OvCa. Results We constructed a lncRNA-mediated competing endogenous RNA (ceRNA) regulatory network that affects the expression of many EMT-related protein-coding genes in mesenchymal OvCa. Using a combination of in vitro and in vivo studies, we provided evidence that the lncRNA PTAF-miR-25-SNAI2 axis controlled EMT in OvCa. Our results revealed that up-regulated PTAF induced elevated SNAI2 expression by competitively binding to miR-25, which in turn promoted OvCa cell EMT and invasion. Moreover, we found that silencing of PTAF inhibited tumor progression and metastasis in an orthotopic mouse model of OvCa. We then observed a significant correlation between PTAF expression and EMT markers in OvCa patients. Conclusions The lncRNA PTAF, a mediator of TGF-β signaling, can predispose OvCa patients to metastases and may serve as a potential target for anti-metastatic therapies for mesenchymal OvCa patients.

Heparin Therapy In Dispholidus Typus Envenomation: An Experimental Study

1981 ◽  
Author(s):  
B A Bradlow ◽  
P M Atkinson ◽  
M Rebello ◽  
M C Gaillard
Keyword(s):  
Antithrombin Iii ◽  
Factor Xa ◽  
Heparin Therapy ◽  
In Vivo Studies ◽  
Intrinsic Pathway ◽  
Heparin Resistance ◽  
Very High ◽  
Direct Activator

The coagulant action of Dispholidus typus venom was relatively resistant to inhibition by heparin in vitro. Heparin concentrations that inhibited coagulation due to either intrinsic pathway or Russell’s viper venom activation had little effect on coagulation due to D. Typus venom. At very high heparin to venom ratios, similar to ratios attainable in vivo this resistance could be overcome. The resistance could not be attributed to an abnormal thrombin produced by the venom since the thrombin produced from purified prothrombin by venom action reacted similarly to the thrombin produced by Factor Xa activation with purified antithrombin III. Thrombin produced from whole plasma by venom action also reacted similarly to physiological thrombin with antithrombin III in a crossed immunoelectrophoresis system. Incubation of venom with heparin and with antithrombin III did not alter the activities of these inhibitors. The heparin resistance may therefore be due to the fact that the venom is a direct activator of prothrombin. In vivo studies in rabbits indicated that heparin administered simultaneously with venom delayed the onset and reduced the severity of disseminated intravascular coagulation. Heparin administered later was much less effective. Early heparin therapy may be of value in human victims when specific antivenom is not available.

scholarly journals Inactivation of factor XIa in human plasma assessed by measuring factor XIa-protease inhibitor complexes: major role for C1-inhibitor

Blood ◽  
1995 ◽  
Vol 85 (6) ◽  
pp. 1517-1526 ◽  
Author(s):  
WA Wuillemin ◽  
M Minnema ◽  
JC Meijers ◽  
D Roem ◽  
AJ Eerenberg ◽  
...  
Keyword(s):  
Protease Inhibitor ◽  
Human Plasma ◽  
Antithrombin Iii ◽  
C1 Inhibitor ◽  
Relative Contribution ◽  
Factor Xia ◽  
Immunosorbent Assays ◽  
Alpha 1 Antitrypsin

From experiments with purified proteins, it has been concluded that factor XIa (FXIa) is inhibited in plasma mainly by alpha 1-antitrypsin (a1AT), followed by antithrombin III (ATIII), C1-inhibitor (C1Inh), and alpha 2-antiplasmin (a2AP). However, the validity of this concept has never been studied in plasma. We established the relative contribution of different inhibitors to the inactivation of FXIa in human plasma, using enzyme-linked immunosorbent assays (ELISAs) for the quantification of complexes of FXIa with a1AT, C1Inh, a2AP, and ATIII. We found that 47% of FXIa added to plasma formed complexes with C1Inh, 24.5% with a2AP, 23.5% with a1AT, and 5% with ATIII. The distribution of FXIa between these inhibitors in plasma was independent of whether FXIa was added to plasma, or was activated endogenously by kaolin, celite, or glass. However, in the presence of heparin (1 or 50 U/mL), C1Inh appeared to be the major inhibitor of FXIa, followed by ATIII. Furthermore, at lower temperatures, less FXIa-C1Inh and FXIa-a1AT complexes but more FXIa-a2AP complexes were formed. These data demonstrate that the contribution of the different inhibitors to inactivation of FXIa in plasma may vary, but C1Inh is the principal inhibitor under most conditions.

Detection of Activation of the Contact System of Coagulation In Vitro and In Vivo: Quantitation of Activated Hageman Factor-C1-Inhibitor and Kallikrein-C1-Inhibitor Complexes by Specific Radioimmunoassays

1987 ◽  
Vol 58 (02) ◽  
pp. 778-785 ◽  
Author(s):  
J H Nuijens ◽  
C C M Huijbregts ◽  
M Cohen ◽  
G O Navis ◽  
A de Vries ◽  
...  
Keyword(s):  
Contact System ◽  
Factor Xii ◽  
Plasma Samples ◽  
C1 Inhibitor ◽  
Hageman Factor ◽  
Plasma Factor ◽  
Factor Xiia ◽  
Kallikrein Activity

SummaryRadioimmunoassays (RIAs) for the detection of C1-inhihitor (C1-Inh) complexed to either kallikrein or activated Hageman factor (factor XIIa) are described. Kallikrein-C1-Inh or factor XIIa-C1-Inh complexes were bound to Scpharosc to which monospecific antibodies against (pre)kallikrein or factor XII, respectively, were coupled. Bound complexes were subsequently detected by an incubation with affinity purified 125I-labeled antibodies against Ci-Inh. These RIAs were used to detect activation of the contact system of coagulation in vitro and in vivo. Addition of dextran sulfate (DXS) (20 μg/ml) to fresh plasma resulted at 37° C in the rapid generation of amidolytic kallikrein activity, which was maximal after 1 to 2 min of incubation and subsequently decreased within a few minutes. The generation of kallikrein activity coincided with the appearance of both kallikrein-C1-Inh and factor XIIa-C1-Inh complexes. However, in contrast to kallikrein activity, both types of complexes remained detectable in the incubation mixtures during the incubation period. Experiments with purified kallikrein, C1-Inh and partly purified β-factor XIIa, and activation experiments in plasmas deficient in either factor XII or prekallikrein, demonstrated the specificity of both RIAs. The minimal amount of DXS that resulted in the generation of measurable amounts of both types of complexes in plasma was 2-3 μg per ml. Similar experiments with kaolin showed that with limiting amounts of activator (1-2 mg/ ml), only kallikrein-C1-Inh complexes were detected in plasma. When larger amounts of kaolin were added to plasma, factor XIIa-C1-Inh complexes were additionally detected in plasma. In plasma samples obtained from healthy donors under conditions that prevented activation of the contact system in vitro, very low levels of both factor XIIa-C1-Inh and kallikrein-C1-Inh complexes were measured, representing approximately 0.3% activation of both factor XII and prekallikrein. In serial plasma samples from a patient with adult respiratory distress syndrome, increased levels of both types of complexes were detected. The radioimmunoassays described in this paper provide useful tools to detect activation of the contact system in vitroas well as in vivo.

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