Regulation of Proinflammatory Activation of Cells RBL-2H3 by Activated Protein C and PAR1 Agonist Peptide

SummaryForty-eight healthy pregnant women were studied prospectively and longitudinally. Blood sampling was performed at 10-15, 23-25, 32-34 and 38-40 weeks of gestation, within one week and at eight weeks postpartum. Classic and modified activated protein C ratio decreased as pregnancy progressed. In the third trimester 92% of the ratios measured with the classic test were above the lower reference level whereas all modified test ratios were normal. Slight activation of blood coagulation was shown with increased levels of prothrombin fragment 1+2, soluble fibrin and D-dimer. Fibrinogen, factor VIII and plasminogen activator inhibitor type 1 and type 2 increased. Protein S and tissue plasminogen activator activity decreased. Protein C remained unchanged. No correlation was found between the decrease in classic APC ratio and changes in factor VIII, fibrinogen, protein S, prothrombin fragment 1+2 or soluble fibrin, nor between the increase in soluble fibrin and changes in prothrombin fragment 1+2, fibrinogen and D-dimer.

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Dermatan Sulfate and LMW Heparin Enhance the Anticoagulant Action of Activated Protein C

Thrombosis and Haemostasis ◽

10.1055/s-0037-1614856 ◽

1999 ◽

Vol 82 (11) ◽

pp. 1462-1468 ◽

Cited By ~ 22

Author(s):

José Fernández ◽

Jari Petäjä ◽

John Griffin

Keyword(s):

Molecular Weight ◽

Unfractionated Heparin ◽

Protein C ◽

Dermatan Sulfate ◽

Anticoagulant Activity ◽

Activated Protein C ◽

Factor V ◽

Factor Va ◽

Anticoagulant Action

SummaryUnfractionated heparin potentiates the anticoagulant action of activated protein C (APC) through several mechanisms, including the recently described enhancement of proteolytic inactivation of factor V. Possible anticoagulant synergism between APC and physiologic glycosaminoglycans, pharmacologic low molecular weight heparins (LMWHs), and other heparin derivatives was studied. Dermatan sulfate showed potent APC-enhancing effect. Commercial LMWHs showed differing abilities to promote APC activity, and the molecular weight of LMWHs correlated with enhancement of APC activity. Degree of sulfation of the glycosaminoglycans influenced APC enhancement. However, because dextran sulfates did not potentiate APC action, the presence of sulfate groups per se on a polysaccharide is not sufficient for APC enhancement. As previously for unfractionated heparin, APC anticoagulant activity was enhanced by glycosaminoglycans when factor V but not factor Va was the substrate. Thus, dermatan sulfate and LMWHs exhibit APC enhancing activity in vitro that could be of physiologic and pharmacologic significance.

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Resistance to Activated Protein C and Factor V Leiden as Risk Factors for Venous Thrombosis

Thrombosis and Haemostasis ◽

10.1055/s-0038-1642720 ◽

1995 ◽

Vol 74 (01) ◽

pp. 449-453 ◽

Cited By ~ 99

Author(s):

Rogier M Bertina ◽

Pieter H Reitsma ◽

Frits R Rosendaal ◽

Jan P Vandenbroucke

Keyword(s):

Risk Factors ◽

Venous Thrombosis ◽

Protein C ◽

Activated Protein C ◽

Factor V Leiden ◽

Factor V

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Factors IXa, Xa, Xla and Activated Protein C Do Not Have Protein C Activating Ability in the Presence of Thrombomodulin

Thrombosis and Haemostasis ◽

10.1055/s-0038-1642787 ◽

1988 ◽

Vol 59 (02) ◽

pp. 339-339 ◽

Cited By ~ 4

Author(s):

E Anne Thompson ◽

Hatem H Salem

Keyword(s):

Protein C ◽

Activated Protein C

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Resistance to Activated Protein C – Diagnostic Strategy in a Laboratory of Haemostasis

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649903 ◽

1995 ◽

Vol 74 (04) ◽

pp. 1197-1198 ◽

Cited By ~ 10

Author(s):

M F Aillaud ◽

E Succo ◽

M C Alessi ◽

J M Gandois ◽

P Gallian ◽

...

Keyword(s):

Protein C ◽

Activated Protein C ◽

Diagnostic Strategy

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Characterization of a cDNA for Rhesus Monkey Protein C Inhibitor – Evidence for N-Terminal Involvement in Heparin Stimulation

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649885 ◽

1995 ◽

Vol 74 (04) ◽

pp. 1079-1087 ◽

Cited By ~ 8

Author(s):

Klaus-P Radtke ◽

José A Fernández ◽

Bruno O Villoutreix ◽

Judith S Greengard ◽

John H Griffin

Keyword(s):

Rhesus Monkey ◽

Protein C ◽

Activated Protein C ◽

Pcr Amplification ◽

Amino Acid Sequences ◽

Heparin Binding ◽

Reactive Center ◽

Protein C Inhibitor ◽

Polymerase Chain

SummarycDNAs for protein C inhibitor (PCI) were cloned from human and rhesus monkey 1 liver RNAs by reverse transcription and polymerase chain reaction (PCR) amplification. Sequencing showed that rhesus monkey and human PCI cDNAs were 93% identical. Predicted amino acid sequences differed at 26 of 387 residues. Pour of these differences (T352M, N359S, R362K, L3631) were in the reactive center loop that is important for inhibitory specificity, and two were in the N-terminal helix (M8T, E13K) that is implicated in glycosaminoglycan binding. PCI in human or rhesus monkey plasma showed comparable inhibitory activity towards human activated protein C in the presence of 10 U/ml heparin. However, maximal acceleration of the inhibition of activated protein C required 5-fold lower heparin concentration for rhesus monkey than for human plasma, consistent with the interpretation that the additional positive charge (E13K) in a putative-heparin binding region increased the affinity for heparin.

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“Pseudo Homozygous” Activated Protein C Resistance due to Double Heterozygous Factor V Defects (Factor V Leiden Mutation and Type I Quantitative Factor V Defect) Associated with Thrombosis: Report of Two Cases Belonging to Two Unrelated Kindreds

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650290 ◽

1996 ◽

Vol 75 (03) ◽

pp. 422-426 ◽

Cited By ~ 53

Author(s):

Paolo Simioni ◽

Alberta Scudeller ◽

Paolo Radossi ◽

Sabrina Gavasso ◽

Bruno Girolami ◽

...

Keyword(s):

Protein C ◽

Dna Analysis ◽

Activated Protein C ◽

Factor V Leiden ◽

Type I ◽

Factor V ◽

Factor V Leiden Mutation ◽

Thrombotic Risk ◽

Apc Resistance ◽

Quantitative Factor

SummaryTwo unrelated patients belonging to two Italian kindreds with a history of thrombotic manifestations were found to have a double heterozygous defect of factor V (F. V), namely type I quantitative F. V defect and F. V Leiden mutation. Although DNA analysis confirmed the presence of a heterozygous F. V Leiden mutation, the measurement of the responsiveness of patients plasma to addition of activated protein C (APC) gave results similar to those found in homozygous defects. It has been recently reported in a preliminary form that the coinheritance of heterozygous F. V Leiden mutation and type I quantitative F. V deficiency in three individuals belonging to the same family resulted in the so-called pseudo homozygous APC resistance with APC sensitivity ratio (APC-SR) typical of homozygous F. V Leiden mutation. In this study we report two new cases of pseudo homozygous APC resistance. Both patients experienced thrombotic manifestations. It is likely that the absence of normal F. V, instead of protecting from thrombotic risk due to heterozygous F. V Leiden mutation, increased the predisposition to thrombosis since the patients became, in fact, pseudo-homozygotes for APC resistance. DNA-analysis is the only way to genotype a patient and is strongly recommended to confirm a diagnosis of homozygous F. V Leiden mutation also in patients with the lowest values of APC-SR. It is to be hoped that no patient gets a diagnosis of homozygous F. V Leiden mutation based on the APC-resi-stance test, especially when the basal clotting tests, i.e., PT and aPTT; are borderline or slightly prolonged.

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A Novel Functional Assay of Protein C in Human Plasma and fts Comparison with Amidolytic and Anticoagulant Assays

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648377 ◽

1992 ◽

Vol 67 (01) ◽

pp. 046-049 ◽

Cited By ~ 10

Author(s):

H A Guglielmone ◽

M A Vides

Keyword(s):

Oral Anticoagulant ◽

Protein C ◽

Activated Protein C ◽

Protein S ◽

Normal Subjects ◽

Test Sample ◽

Functional Assay ◽

Fast Method ◽

Factor Va ◽

Protein C Activity

SummaryA simple and fast method for the quantitative determination of protein C activity in plasma is here described. The first step consists in the conversion of protein C in the test sample into activated protein C by means of an activator isolated from Southern Copperhead venom. Subsequently, the degradation of factor Va, in presence of protein C-deficient plasma, is measured by the prolongation of the prothrombin time which is proportional to the amount of protein C in the sample. The dose-response curve showed a linear relationship from 6 to 150% protein C activity and the inter- and intra-assay reproducibility was 3.5% and 5.6% respectively. In normal subjects, a mean of protein C level of 98 ± 15% of normal pooled plasma was found. Comparison with the anticoagulant assay in samples of patients with oral anticoagulant, liver cirrhosis, disseminated intravascular coagulation and severe preeclampsia revealed an excellent correlation (r = 0.94, p <0.001). Also, a similar correlation (r = 0.93, p <0.001) existed between amidolytic assay and the method here proposed for all the samples studied without including the oral anticoagulant group. These results allowed us to infer that this method evaluates the ability of protein C to interact with protein S, phospholipids, calcium ions and factor Va.

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