STUDY ON THE EFFECT OF UNFRACTIONATED (UFH) AND LOW MOLECULAR WEIGHT (LMWH) HEPARINS ON THE DETERMINATION OF PROTEIN C ACTIVITY

1987 ◽  
Author(s):  
N Sala ◽  
J Fontcuberta
Keyword(s):  
Protein C ◽  
Plasma Samples ◽  
Protamine Sulphate ◽  
Vein Thrombosis ◽  
Antigen Elisa ◽  
Before And After ◽  
Control Plasma ◽  
Protein C Activity

In an attempt to see whether the presence of different heparins affected the determination of protein C activity (APC),this parameter was measured before and during treatment in 23 deep vein thrombosis patients that had been randomly treated with 3 different LMWH (Choay CY-216 and CY-222 and Kabi-2165) and UFH,for 10 days, Very low levels of APC (amidolytic assay that uses thrombin-thrombomodulin to activate the barium citrate eluted PC) were found in those patients receiving UFH and having an APTT more than 3 times that of control, as well as in those patients receiving LMWH CY-216 and having an APTT of only 8 to 10 seconds higher than that of control plasma, In patients receiving CY-222 and Kabi-2165, no significant differences were observed between APC levels before and during treatment, PC antigen (ELISA assay) was normal in all cases, In order to see if these low APC levels were due to interference of heparin with the assay and at which doses, control plasma pool was supplemented "in vitro" with 0 to 2.5 IU/ml (0 to 0,00252) of UFH and with 0 to 3 anti-Xa U/ml of LMWH CY-216, APTT, PCAg, APC and presence of ATI 11 in the barium citrate eluates (immunodiffusion), were determined in all plasma samples before and after treatment with protamine sulphate (PS) at 0,0032, The results showed that UFH, when not neutralized with PS, resulted in low APC values only at doses higher than 0,8 IU/ml, corresponding to an APTT of more than 3 times that of control plasma, LMWH CY-216 at doses above 1 anti-XaU/ml, corresponding to an APTT of only 10 seconds higher than that of control, also produced a gradual decrease in APC values, ATI 11 was clearly visualized in the barium citrate eluates of all those plasma samples having a low APC value, The addition of PS to all samples containing UFH resulted in a complete normalization of APC values, with almost normal AFTT values and disappearance of ATI 11 from the barium citrate eluates, On the contrary, addition of PS to plasma containing CY-216 resulted in low APC values and presence of ATI 11 in the eluates of those samples containing more than 4 antiXaU/ml, whose APTT still was about 10 seconds above that of control.It is concluded that at therapeutic doses not only UFH but also LMWH CY-216 interfere with the APC assay, probably through binding of hepar in-ATI 11 complexes to barium citrate and neutralization of the thrombin used to activate the barium citrate eluted PC, LMWH CY-222 and Kabi-2165, although increasing the APTT similarly to CY-216, do not seem to interfere with the APC assay, Protamine sulphate, at 0,0032 in plasma, completely abolishes the effect of UFH on APC assay but not that of LMWH CY-216, More studies are being performed to see if higher doses of PS can be used to neutralize the effect of this LMWH.

Coagulation Activation in Extracorporeal Hemodialysis

1997 ◽  
Vol 20 (3) ◽  
pp. 163-165 ◽  
Author(s):  
M. Camici ◽  
L. Evangelisti ◽  
P. Balestri ◽  
L. Cioni ◽  
P. Fundi ◽  
...  
Keyword(s):  
Protein C ◽  
Serum Lipoprotein ◽  
Factor Vii ◽  
Maintenance Hemodialysis ◽  
Factor X ◽  
Lipoprotein A ◽  
Activity Factor ◽  
Before And After ◽  
Protein C Activity

The Authors evaluated the behavior of protein C activity, factor X and factor VII coagulant activity and serum lipoprotein(a) before and after dialytic treatment in patients on maintenance hemodialysis. They observed depressed protein C activity that significantly (p<0.005) increased and became normal immediately after hemodialysis while factor X and factor VII increased (p<0.01; p<0.05) despite heparinization together with amount of serum lipoprotein(a). In vitro incubation (30 'at 37°C) of uremic and healthy blood showed a decrease in serum lipoprotein(a) concentration. After heparin addition (final concentration 0.5 U/ml) lipoprotein(a) increased in the uremic blood only. The clinical and physiopathological implications of these results are discussed.

DETERMINATION OF BLOOD CORTICOIDS USING THE IN VITRO RESIN UPTAKE OF 3H-PREDNISOLONE

1968 ◽  
Vol 57 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Hironori Nakajima ◽  
Mitsunori Murala ◽  
Masumitsu Nakata ◽  
Takeshi Naruse ◽  
Seiji Kubo
Keyword(s):  
Thyroid Function Test ◽  
Normal Subjects ◽  
Adrenal Function ◽  
Function Test ◽  
Before And After ◽  
Adrenal Response ◽  
Suppression Test

ABSTRACT The in vitro resin uptake of 3H-prednisolone was used for the determination of blood cortisol after addition of radioactive prednisolone followed by Amberlite CG 400 Type 1 to the test serum, and incubation of the mixture. The radioactivity of the supernatant was compared before and after the addition of the resin. The principle of this method is similar to that of the 131I-triiodothyronine resin uptake for the thyroid function test. The tests for the specificity, reproducibility and sensitivity gave satisfactory results. The mean basal value ± SD of the 3H-prednisolone resin uptake was 35.3 ± 9.2% in normal subjects, and 27.1 ± 4.8% in pregnant women. This method was valid in various adrenal function tests, i. e. the adrenal circadian rhythm, corticotrophin (ACTH) test, dexamethasone suppression test and the adrenal response to lysine-8-vasopressin. It proved to be a sensitive indicator of the adrenal function. These results suggest that this method should be useful for a routine adrenal function test.

AN ACCURATE METHOD FOR THE ESTIMATION OF LOW CONCENTRATIONS OF DEXTRAN IN PLASMA

1957 ◽  
Vol 35 (6) ◽  
pp. 383-390 ◽  
Author(s):  
Robert E. Semple
Keyword(s):  
Aqueous Extract ◽  
Accurate Method ◽  
Protein Precipitation ◽  
In Vitro Tests ◽  
Plasma Samples ◽  
Carbohydrate Concentration ◽  
Low Concentrations ◽  
Standard Deviations

A method is presented for the determination in plasma of small (50–150 mg./100 ml.) amounts of dextran. The procedure, which requires between 3 and 4 hours, consists of protein precipitation, glucose removal by dialysis, and the determination of the carbohydrate concentration of the resulting aqueous extract by a modified anthrone technique. Results of in vitro tests show that average dextran recovery is essentially 100% and that standard deviations in recovery range from 1.7 to 2.5% depending upon the dextran concentration. Deviations are reduced to a range of 1.4–1.7% by the use of duplicate plasma samples.

AMIDOLYTIC DETERMINATION OF ANTI-ACTIVATED PROTEIN C ACTIVITY IN PLASMA

1987 ◽  
Author(s):  
F Nicham ◽  
J L Martinoli
Keyword(s):  
Protein C ◽  
Activated Protein C ◽  
Type I ◽  
Peptide Substrate ◽  
Normal Plasma ◽  
Clinical Investigations ◽  
Normal Individuals ◽  
Significant Difference ◽  
Protein C Activity

Anti-activated protein C (anti-APC) potency of plasma was studied using purified bovine activated protein C (Bovine APC) and the chromogenic peptide substrate CBS 65.25. The choice of bovine instead of human APC was justified by a better sensitivity (Km = 0.14 and 0.42 mM respectively). Inhibition was shown to be dramatically enhanced by the presence of Heparin and calcium. No significant difference occurred for pH values up to 8.2 for both inhibition and hydrolysis reactions.In the final test, O.l ml of 1:5 diluted plasma (Tris buffer saline, pH 8.4, containing 5 U/ml of Heparin) were incubated at 37°C with 0.2 ml of Bovine APC (0.125 U/ml). After 10 minutes of inhibition, 0.2 ml of CBS 65.25 (1.5 mM/1) were added to the mixture and the change in absorbance was recorded at 405 nm for 2 minutes. In these conditions linearity of the dose-response curve was ensured from O up to 130 % of activity (normal plasma pool being assigned to 100 %) ; day to day precision was 1.9 %. When a normal plasma was overloaded with different purified inhibitors such as antithrombin III, cl-esterase inactivator, alpha 2 macroglobulin, the measured anti-APC activities were not affected at all. It could be concluded that this test measures protein C inhibitor described by Suzuki.Levels in 23 normal individuals averaged 97.7 %, giving a normal range of 77 - 118 %. Levels were below normal in 6 of 10 patients after surgery (54.1 +/- 4.8 %), in 18 of 19 patients with liver disease (49.5 +/- 9.6 %) and in 4 of 18 coumarin treated patients (54.9 +/- 6.5 %). In 9 of 10 patients previou sly characterized as type I protein C deficient, a statistically significant increase in anti-APC activity was observed (mean 110.7 +/- 7.7 %).The use of a chromogenic peptide substrate has led to a sensitive and fast assay for anti-APC activity in plasma. That could be of interest in clinical investigations and knowledge of regulatory mechanisms in thrombotic disorders.

scholarly journals Complex formation between urokinase and plasma protein C inhibitor in vitro and in vivo

Blood ◽  
1989 ◽  
Vol 74 (2) ◽  
pp. 722-728 ◽  
Author(s):  
M Geiger ◽  
K Huber ◽  
J Wojta ◽  
L Stingl ◽  
F Espana ◽  
...  
Keyword(s):  
Complex Formation ◽  
Protein C ◽  
Specific Activity ◽  
Ex Vivo ◽  
Plasminogen Activator Inhibitor ◽  
Enzyme Linked Immunosorbent Assay ◽  
Plasma Samples ◽  
Protein C Inhibitor

Abstract Protein C inhibitor (PCI) and plasminogen activator inhibitor 3 (PAI-3; urinary urokinase inhibitor) are immunologically identical. The role of PCI for urokinase (uPA) inhibition in vivo was investigated. We therefore developed an enzyme-linked immunosorbent assay (ELISA) specific for uPA-PCI complexes: Rabbit anti-PCI IgG was immobilized on a microtiter plate and following incubation with uPA-PCI complex- containing samples, bound uPA-PCI complexes were quantified with a horseradish-peroxidase-linked monoclonal antibody (MoAb) to uPA. Using this assay, time, dose, and heparin-dependent complexes were detected when uPA was incubated with normal plasma or purified urinary PCI, whereas no complexes were measurable using PCI-immunodepleted plasma. Plasma samples (containing 20 mmol/L benzamidine to prevent complex formation ex vivo) from patients undergoing systemic urokinase therapy (1 x 10(6) IU/60 min intravenously [IV]) after myocardial infarction were also studied. uPA present in these plasma samples (up to 1,200 ng/mL) had only 43% to 70% of the specific activity of purified 2-chain uPA, suggesting that a major portion of uPA is complexed to inhibitors. In these plasma samples uPA-PCI complexes were present in a concentration corresponding to 21% to 25% of inactive uPA antigen. These data suggest that at high uPA concentrations, such as during uPA therapy, plasma PCI might contribute significantly to uPA inhibition in vivo.

No effect of fasting plasma total homocysteine on protein C activity in vitro

Blood ◽  
2003 ◽  
Vol 101 (6) ◽  
pp. 2446-2446 ◽  
Author(s):  
GianMarco Podda ◽  
Elena M. Faioni ◽  
Maddalena L. Zighetti ◽  
Marco Cattaneo
Keyword(s):  
Protein C ◽  
Fasting Plasma ◽  
Total Homocysteine ◽  
Plasma Total Homocysteine ◽  
Protein C Activity

scholarly journals DETERMINATION OF l-HISTIDINE IN NANOGRAM AMOUNTS AND THE QUESTION OF ITS OCCURRENCE IN MAST CELLS

1972 ◽  
Vol 20 (11) ◽  
pp. 917-922 ◽  
Author(s):  
DAVID I. WILKINSON ◽  
DAVID GLICK
Keyword(s):  
Mast Cells ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Peritoneal Mast Cells ◽  
Before And After ◽  
Chromatographic Detection ◽  
Rat Peritoneal Mast Cells ◽  
Rate Limiting

In an attempt to clarify the question of whether histidine is stored in the mast cell for coversion to histamine or whether the rate of conversion is rapid enough to prevent accumulation of histidine so that the rate-limiting step is the histidine uptake, it was found that no histidine was demonstrable in rat peritoneal mast cells by either quantitative analysis or paper chromatographic detection. Microadaptation of Hassall's method, based on conversion of l-histidine by histidase to urocanic acid and measurement of the latter by its absorbance at 277 nm, was made to permit determination of histidine in nanogram amounts in the presence of histamine. This adaptation was found reliable when compared with the o-phthalaldehyde method in estimation of l-histidine in serum and in insulin hydrolysate, and then it was applied to analysis of mast cells before and after l-histidine uptake in vitro. The adaptation should be generally useful in microanalysis of l-histidine in histologically and cytologically defined samples.

scholarly journals Hot-Stage Microscopy for Determination of API Particles in a Formulated Tablet

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Michal Šimek ◽  
Veronika Grünwaldová ◽  
Bohumil Kratochvíl
Keyword(s):  
Active Pharmaceutical Ingredient ◽  
Assessment Method ◽  
Hot Stage Microscopy ◽  
Tablet Disintegration ◽  
Before And After ◽  
In Vitro Assessment ◽  
Active Substances ◽  
Good Agreement

Although methods exist to readily determine the particle size distribution (PSD) of an active pharmaceutical ingredient (API) before its formulation into a final product, the primary challenge is to develop a method to determine the PSD of APIs in a finished tablet. To address the limitations of existing PSD methods, we used hot-stage microscopy to observe tablet disintegration during temperature change and, thus, reveal the API particles in a tablet. Both mechanical and liquid disintegration were evaluated after we had identified optimum milling time for mechanical disintegration and optimum volume of water for liquid disintegration. In each case, hot-stage micrographs, taken before and after the API melting point, were compared with image analysis software to obtain the PSDs. Then, the PSDs of the APIs from the disintegrated tablets were compared with the PSDs of raw APIs. Good agreement was obtained, thereby confirming the robustness of our methodology. The availability of such a method equips pharmaceutical scientists with an in vitro assessment method that will more reliably determine the PSD of active substances in finished tablets.

Determination of anti-Müllerian hormone concentrations in blood as a tool to select Holstein donor cows for embryo production: from the laboratory to the farm

2012 ◽  
Vol 24 (7) ◽  
pp. 932 ◽  
Author(s):  
Charlène Rico ◽  
Laurence Drouilhet ◽  
Pascal Salvetti ◽  
Rozenn Dalbiès-Tran ◽  
Peggy Jarrier ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Plasma Samples ◽  
In Vitro Production ◽  
Experimental Station ◽  
Multiple Ovulation ◽  
Practical Information ◽  
Vitro Production ◽  
Donor Cows

High between-animal variability in the number of embryos produced by multiple ovulation and embryo transfer (MOET) and ovum pick-up and in vitro production (OPU–IVP) methods remains a major limit to the development of embryo biotechnologies in cattle. The measurement of anti-Müllerian hormone (AMH) endocrine concentrations in cows can help to predict their follicular and ovulatory responses to gonadotrophin treatment. The present study aimed to provide practical information for a simple prognostic method based on AMH measurement in Holstein cows. Accurate AMH concentrations could be measured with ELISA in blood or plasma. In cows undergoing repeated OPU protocols over 1 year, the AMH concentrations measured in plasma samples collected before each gonadotrophin treatment were found to be highly repeatable and were tightly correlated with follicular responses. From data obtained at both an experimental station and farm settings, it was possible to propose AMH cut-off values to identify low-responding cows. Gonadotrophin-stimulated cows producing fewer than 15 large follicles at oestrus and fewer than 10 embryos in MOET protocols could be discarded efficiently with plasma AMH concentrations below 87 and 74 pg mL–1, respectively. In conclusion, we propose a prognostic method based on a single AMH measurement to improve the results of embryo biotechnologies.

scholarly journals Evidence of Thrombin-Independent Generation of Activated Protein C

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2568-2568
Author(s):  
Heiko Rühl ◽  
Janine Rossa ◽  
Christina Berens ◽  
Anna Winterhagen ◽  
Johannes Oldenburg ◽  
...  
Keyword(s):  
Protein C ◽  
De Novo ◽  
Activated Protein C ◽  
Autologous Serum ◽  
Thrombin Inhibitor ◽  
Thrombin Time ◽  
Plasma Samples ◽  
In Vitro Experiments ◽  
Healthy Human

Abstract Introduction: In a recent study, we performed autologous serum infusions to evaluate the elimination kinetics of hemostasis-related biomarkers in healthy human subjects. In order to monitor a serum-induced activation of coagulation, we measured free thrombin in the infused serum and in plasma samples taken during and after infusion, but did not detect any de novo thrombin formation [PLoS One. 2015; 10(12): e0145012]. To study if the low levels of free thrombin in the infused serum induce generation of activated protein C (APC) we additionally measured APC in samples drawn after autologous serum infusion and in vitro in a purified system. Methods: Autologous serum was infused (50 mL/30 min) into 19 healthy volunteers. Four of them were simultaneously receiving infusions of the thrombin inhibitor argatroban (1 µg/kg/min), initiated 1 h before and ceased 1 h after starting the infusion of serum. Thrombin and APC were measured in serum and in plasma samples drawn before and in 15-min intervals during the infusion of serum, using a highly-sensitive oligonucleotide-based enzyme capture assay (OECA) platform. In in vitro experiments, APC formation was induced by addition of purified thrombin or serum to buffer containing protein C and thrombomodulin in excess, and CaCl2 at physiological concentrations. The formation of APC was subsequently measured by OECA. Results: In the autologous serum median (interquartile range) concentrations of thrombin and APC were 6.68 (4.63 - 8.73) ng/mL and 9.17 (7.63 - 13.91) ng/mL, thus doses of 0.12 (0.07 - 0.15) ng/mL of thrombin and 0.16 (0.14 - 0.22) ng/mL of APC were infused per mL of the subjects' plasma volume. In the plasma of probands, that did not receive argatroban, peak thrombin levels of 0.04 (0.00 - 0.08) ng/mL were measured, indicating a rapid inactivation of thrombin by endogenous inhibitors present in the plasma. However, with 1.41 (0.76 - 2.97) ng/mL peak APC levels exceeded the infused APC doses by a multiple. This was also true for the plasma samples from the probands that received argatroban, in which peak levels of APC of 0.94 (0.79 - 1.22) ng/mL were measured despite thrombin inhibition indicated by prolongation of the aPTT of 42.9 (40.1 - 44.4) s and thrombin time of 78.3 (69.3 - 87.2) s. In the in vitro experiments addition of argatroban at the concentrations achieved in the probands completely abolished APC generation up to a thrombin concentration of 5 ng/ml. Addition of human serum as a source for thrombin in the same purified system consistently induced generation of greater amounts of APC than expected on the basis of the amount of thrombin present in the serum samples. Conclusions: The data obtained provide evidence for a thrombin-independent mechanism of APC formation. Further in vitro studies with endothelial cells are required to identify the components that are involved in this alternative way of APC generation. Disclosures Rühl: CSL Behring: Research Funding; Bayer: Consultancy, Honoraria. Müller:Novo Nordisk: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

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