scholarly journals Free Protein S Activity Actual to Control Ratio Measurement

2020 ◽  
Author(s):  
Keyword(s):  
Protein S ◽  
Ratio Measurement ◽  
Free Protein ◽  
Protein S Activity

Functional and Immunologic Protein S in Normal Pregnant Women and in Full-Term Newborns

1989 ◽  
Vol 61 (03) ◽  
pp. 474-478 ◽  
Author(s):  
José A Fernández ◽  
Amparo Estellés ◽  
Juan Gilabert ◽  
Francisco España ◽  
Justo Aznar
Keyword(s):  
Activated Protein C ◽  
Protein S ◽  
Test Sample ◽  
Full Term ◽  
Functional Assay ◽  
Major Protein ◽  
Functional Protein ◽  
Free Protein ◽  
Term Newborns ◽  
Protein S Activity

SummaryTotal and free protein S antigen and C4b-binding protein (C4bp) were determined by rocket immuno-electrophoresis, and functional protein S was assayed by a coagulation method, throughout pregnancy and normal puerperium and in a group of normal full-term newborns (FTN). The functional protein S assay is based on a modification of the APTT, using a mixture of test sample, protein S deficient plasma, activated protein C, phospholipids and calcium. This protein S functional assay is specific for protein S since the APTT prolongation by normal plasma was abolished by incubation of plasma with monospecific, rabbit antiprotein S IgG. The ratios of functional protein S/free protein S antigen in healthy men (n = 13) and women (n = 14) were 1.0 ± 0.13 (mean ± SD) and 1.03 ± 0.20, respectively. During pregnancy there is a decrease in functional protein S and a progressive decrease in total and free protein S antigen, with a functional/free protein S ratio of 0.75 ± 0.28 in the third trimester of pregnancy (n = 16). In early puerperium the functional protein S level was lower than the free protein S antigen level (ratio about 0.5). In the FTN group, the free protein S level was 39% and protein S activity was about 70% that of adults, with a functional/free protein S ratio of 1.84 ± 0.31. C4bp values were 23.5 ± 10.3% in the FTN group, and crossed immunoelectrophoresis showed that in this group the major protein S peak corresponded to free protein S. These results indicate that both in early puerperium and in FTN group, free protein S antigen may not be an adequate parameter for estimating of functional protein S activity. The decrease in functional protein S activity during early puerperium may be connected with the risk of developing thrombotic episodes during the postpartum period.

Comparison of Functional Assays for Protein S: European Collaborative Study of Patients with Congenital and Acquired Deficiency

1993 ◽  
Vol 70 (06) ◽  
pp. 0946-0950 ◽  
Author(s):  
C Boyer-Neumann ◽  
R M Bertina ◽  
A Tripodi ◽  
A D'Angelo ◽  
M Wolf ◽  
...  
Keyword(s):  
Total Protein ◽  
Collaborative Study ◽  
Protein S ◽  
Mean Values ◽  
Free Protein ◽  
Functional Assays ◽  
Congenital Deficiency ◽  
Significant Difference ◽  
Free Antigen ◽  
Protein S Activity

SummaryFour functional assays for protein S were evaluated by 4 different laboratories, each center using its own method. The aim of this study was to compare these different assays and to establish a relationship with results of immunological assays of total and free protein S antigen and C4bBP. The same plasma samples were distributed to each center and tested in blind. In 47 normal subjects, there was no significant difference between the 4 functional assays, with mean values ranging from 93 to 100%. These values were in good agreement with those of free and total protein S antigen. In 34 patients with a quantitative congenital deficiency of protein S the mean values of protein S activity were decreased with the 4 assays, ranging from 25 to 40%. Free protein S antigen was reduced to a similar extent, whereas total antigen was either normal or decreased. The correlation of protein S activity with free protein S antigen was satisfactory for 3 methods, with coefficients of correlation varying from 0.84 to 0.92 whereas it was only 0.70 in one lab. When total protein S antigen was reduced, protein S activity was decreased in all the patients with the 4 assays. In contrast when total protein S antigen was normal an important overlap of protein S activity between normals and patients was observed in one lab with 12 patients misclassified. In 8 patients with a functional defect, results of protein S activity differed substantially according to the assay used and about half of these patients were misclassified. In patients with inflammatory disease, protein S activity was normal with the 4 assays, in good correlation with free antigen, despite high levels of both C4bBP and total protein S antigen. In patients with oral anticoagulants, protein S activity was low with all assays. Only with one assay, protein S activity was significantly lower than free antigen, suggesting that this assay is sensitive to the hypo-carboxylated protein. Variable values of protein S activity were observed in patients with liver cirrhosis, with relatively little agreement between methods. As discordant results were obtained in some patients with dysfunctional protein S deficiency and acquired disorders, these methods do not necessarily measure the same cofactor of activated protein C. However this study indicates that all 4 functional protein S assays give similar results in normals, and almost all patients with a quantitative congenital deficiency.

scholarly journals Estimates of Within-Subject Biological Variation of Protein C, Antithrombin, Protein S Free, Protein S Activity, and Activated Protein C Resistance in Pregnant Women

2017 ◽  
Vol 63 (4) ◽  
pp. 898-907 ◽  
Author(s):  
Ann H Kristoffersen ◽  
Per H Petersen ◽  
Thomas Røraas ◽  
Sverre Sandberg
Keyword(s):  
Protein C ◽  
Activated Protein C ◽  
Protein S ◽  
Biological Variation ◽  
Physiological Changes ◽  
Activated Protein C Resistance ◽  
Coagulation Parameters ◽  
Free Protein ◽  
Protein S Activity ◽  
In Pregnancy

Abstract BACKGROUND In pregnancy, interpretation of results from coagulation parameters can be difficult because of the procoagulant physiological changes. The aim of this study was to describe the course of 5 coagulation parameters (thrombophilia markers) in healthy pregnancies, and to estimate and compare the within-subject biological variation (CVI) of these parameters in healthy pregnant and nonpregnant women. METHODS Blood samples were obtained every 4th week during pregnancy and 3 samples after delivery in 20 healthy women and every 4th week during 40 weeks in 19 healthy nonpregnant women. Protein C (PC), antithrombin (AT), protein S free (PS free), protein S activity (PS activity), and activated protein C resistance (with factor V–depleted plasma) (APCR) were analyzed. Before the calculation of CVI, results were transformed into multiples of the median (MoM) and natural logarithm of MoM (lnMoM) to adjust for the physiological changes during pregnancy. RESULTS During pregnancy, PC results showed large variability, AT decreased slightly, and PS free and PS activity decreased significantly. Both activated partial thromboplastin time tests used to calculate APCR decreased, and the APCR ratio was constant. The CVI (lnMoM) in pregnancy were for PC 8.4%, for AT 3.8%, for PS free 11.5%, for PS activity 9.3%, and for APCR 0.5%, and similar to corresponding results in nonpregnant women. CONCLUSIONS Transformation of coagulation parameters in healthy pregnancies to lnMoM is a tool to establish a kind of steady state. Although there is a physiological change in PC, AT, and PS free and PS activity during pregnancy, the CVI was comparable with the CVI of nonpregnant women.

Decreased Free Protein S Levels in Polycythemia Vera

1990 ◽  
Vol 64 (01) ◽  
pp. 177-178 ◽  
Author(s):  
M Zoppi ◽  
M Furlan ◽  
G Brun del Re ◽  
W Wuillemin ◽  
B Lämmle
Keyword(s):  
Polycythemia Vera ◽  
Protein S ◽  
Free Protein

Severe Arterial Cerebral Thrombosis in a Patient with Protein S Deficiency (Moderately Reduced Total and Markedly Reduced Free Protein S): A Family Study

1989 ◽  
Vol 61 (01) ◽  
pp. 144-147 ◽  
Author(s):  
A Girolami ◽  
P Simioni ◽  
A R Lazzaro ◽  
I Cordiano
Keyword(s):  
Arterial Thrombosis ◽  
Protein C ◽  
Protein S ◽  
Protein S Deficiency ◽  
Protein C Deficiency ◽  
Free Protein ◽  
Her Family ◽  
S Deficiency ◽  
Increased Risk ◽  
Patient Reported

SummaryDeficiency of protein S has been associated with an increased risk of thrombotic disease as already shown for protein C deficiency. Deficiencies of any of these two proteins predispose to venous thrombosis but have been only rarely associated with arterial thrombosis.In this study we describe a case of severe cerebral arterial thrombosis in a 44-year old woman with protein S deficiency. The defect was characterized by moderately reduced levels of total and markedly reduced levels of free protein S. C4b-bp level was normal. Protein C, AT III and routine coagulation tests were within the normal limits.In her family two other members showed the same defect. All the affected members had venous thrombotic manifestations, two of them at a relatively young age. No other risk factors for thrombotic episodes were present in the family members. The patient reported was treated with ASA and dipyridamole and so far there were no relapses.

A New Functional Assay for Human Protein S Activity Using Activated Factor Vas Substrate

1989 ◽  
Vol 62 (04) ◽  
pp. 1144-1145 ◽  
Author(s):  
Martine Wolf ◽  
Catherine Boyer-Neumann ◽  
Jean-Luc Martinoli ◽  
Catherine Leroy-Matheron ◽  
Amiral Jean ◽  
...  
Keyword(s):  
Protein S ◽  
Human Protein ◽  
Functional Assay ◽  
Protein S Activity

The Relationship between Plasma Microparticles, Protein S and Anticardiolipin Antibodies in Patients with Human Immunodeficiency Virus Infection

1996 ◽  
Vol 76 (01) ◽  
pp. 038-045 ◽  
Author(s):  
Jean-Christophe Gris ◽  
Pierre Toulon ◽  
Sophie Brun ◽  
Claude Maugard ◽  
Christian Sarlat ◽  
...  
Keyword(s):  
Poor Prognosis ◽  
Anticardiolipin Antibody ◽  
Protein S ◽  
Anticardiolipin Antibodies ◽  
Protein S Deficiency ◽  
Free Protein ◽  
Precipitation Technique ◽  
S Deficiency ◽  
Immunodeficiency Virus ◽  
Antibody Titers

SummaryThe high prevalence of free protein S deficiency in human immunodeficiency virus (HlV)-infected patients is poorly understood. We studied 38 HIV seropositive patients. Free protein S antigen values assayed using the polyethylene-glycol precipitation technique (PEG-fS) were statistically lower in patients than in controls. These values using a specific monoclonal antibody-based ELISA (MoAb-fS) and the values of protein S activity (S-act) were not statistically different between patients and controls. C4b-binding protein values were not different from control values. In patients, PEG-fS values were lower than MoAb-fS values. Ten patients had a PEG-fS deficiency, 4 patients had a MoAb-fS deficiency and 8 had a S-act deficiency. Protein S activity and MoAb-fS were lower in clinical groups with poor prognosis and in patients with AIDS but PEG-fS was not. A trend for reduced S-act/MoAb-fS ratios was observed in patients. PEG-fS was negatively correlated with anticardiolipin antibody titers whereas MoAb-fS was not. The plasma of PEG-fS deficient HIV-patients contained high amounts of flow cytometry detectable microparticles which were depleted from plasma by PEG precipitation. The microparticles were partly CD42b and CD4 positive but CD8 negative. These microparticles were labelled by an anti free protein S monoclonal antibody. The observed differences between MoAb-fS and PEG-fS values were correlated with the amount of detectable plasma microparticles, just like the differences between MoAb-fS and S-act. Plasma microparticles correlated with anticardiolipin antibody titers.In summary, free protein S antigen in HIV infected patients is underestimated when the PEG precipitation technique is used due to the presence of elevated levels of microparticles that bind protein S. The activity of free protein S is also impaired by high levels of microparticles. The prevalence of free protein S deficiency in HIV positive patients is lower than previously published (4/38, -10%) and is correlated with poor prognosis. By implication, use of a PEG precipitation technique might give artefactually low free protein S antigen values in other patient groups if high numbers of microparticles are present. In HIV patients, high titers of anticardiolipin antibodies are associated with high concentrations of cell-derived plasma microparticles.

Free Protein S Deficiency Is a Risk Factor for Venous Thrombosis

1997 ◽  
Vol 78 (05) ◽  
pp. 1343-1346 ◽  
Author(s):  
Elena M Faioni ◽  
Carla Valsecchi ◽  
Alessandra Palla ◽  
Emanuela Taioli ◽  
Cristina Razzari ◽  
...  
Keyword(s):  
Risk Factor ◽  
Relative Risk ◽  
Venous Thrombosis ◽  
Protein S ◽  
Unexpected Finding ◽  
Reference Ranges ◽  
Protein S Deficiency ◽  
Men And Women ◽  
Free Protein ◽  
S Deficiency

SummaryA recent study suggests that protein S deficiency is not a risk factor for venous thrombosis. Since this unexpected finding would have important clinical implications if confirmed, we performed a case-control study with the aim to determine the prevalence of protein S deficiency in patients with thrombosis and in healthy individuals taken from the general population and the relative risk of thrombosis in protein S-deficient patients. Free protein S concentration was measured in 327 consecutive patients with at least one venous thrombotic episode and in 317 age- and sex-matched control individuals. Different normal reference ranges were obtained and adopted for men and women. Protein S deficiency was found in 3.1% (95% Cl: 1.5-5.2) of patients and in 1.3% of controls (95% Cl: 0.3-2.8). Ten patients and 4 control subjects had protein S deficiency, which determined a relative risk of thrombosis (sex- and age-adjusted odds ratio) of 2.4 (95% Cl: 0.8-7.9). When men and women were analyzed separately, the risk was 5.0 (95% CI: 0.6-43.6) and 1.6 (95% Cl: 0.4-6.7) respectively. PS-deficient men had more thrombotic episodes than women and later in life. Multivariate analysis established that sex was an independent determinant of the number of episodes, as was age, while PS deficiency was not. However sex and PS deficiency status were both determinants of age at first thrombotic episode.

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