Endogenous Thrombin Potential Peak Height Relative Measurement

2020 ◽  
Author(s):  
Keyword(s):  
Peak Height ◽  
Relative Measurement ◽  
Endogenous Thrombin Potential ◽  
Potential Peak

scholarly journals Whole-Blood Thrombin Generation Monitored with a Calibrated Automated Thrombogram-Based Assay

2012 ◽  
Vol 58 (8) ◽  
pp. 1252-1259 ◽  
Author(s):  
Marisa Ninivaggi ◽  
Rafael Apitz-Castro ◽  
Yesim Dargaud ◽  
Bas de Laat ◽  
H Coenraad Hemker ◽  
...  
Keyword(s):  
Whole Blood ◽  
Thrombin Generation ◽  
Peak Height ◽  
Interindividual Variation ◽  
Rapid Screening ◽  
Physiological Conditions ◽  
Endogenous Thrombin Potential ◽  
Versatile Tool ◽  
Rapid Screening Test ◽  
Clinically Significant

Abstract BACKGROUND The calibrated automated thrombogram (CAT) assay in plasma is a versatile tool to investigate patients with hypo- or hypercoagulable phenotypes. The objective was to make this method applicable for whole blood measurements. METHODS Thin-layer technology and the use of a rhodamine 110–based thrombin substrate appear to be essential for a reliable thrombin generation (TG) assay in whole blood. Using this knowledge we developed a whole blood CAT-based assay. RESULTS We demonstrated that the whole blood CAT-based assay is a sensitive and rapid screening test to assess function of the hemostatic system under more nearly physiological conditions than the TG assay in plasma. Under conditions of low tissue factor concentration (0.5 pmol/L) and 50% diluted blood, the intraassay CV of the thrombogram parameters, endogenous thrombin potential and thrombin peak height, were 6.7% and 6.5%, respectively. The respective interassay CVs were 12% and 11%. The mean interindividual variation (SD) of 40 healthy volunteers was 633 (146) nmol · min/L for the endogenous thrombin potential and 128 (23) nmol/L for the thrombin peak. Surprisingly, erythrocytes contributed more than platelets to the procoagulant blood cell membranes necessary for optimal TG. Statistically significant (P < 0.001) and potentially clinically significant correlations were observed between circulating factor-VIII concentrations in blood of hemophilia A patients and endogenous thrombin potential (r = 0.62) and thrombin peak height (r = 0.58). CONCLUSIONS We have developed a reliable method to measure TG in whole blood. The assay can be performed with a drop of blood and may provide a useful measurement of TG under more physiological conditions than plasma.

Abstract 051: Common Single Nucleotide Polymorphisms in the Coagulation Factor XII Gene (F12) are Associated with Endogenous Thrombin Potential via In Situ Activation of the Intrinsic System of Coagulation: The Cardiovascular Health Study

Circulation ◽  
2013 ◽  
Vol 127 (suppl_12) ◽  
Author(s):  
Nels C Olson ◽  
Saulius Butenas ◽  
Ethan M Lange ◽  
Leslie A Lange ◽  
Nancy S Jenny ◽  
...  
Keyword(s):  
Thrombin Generation ◽  
Cardiovascular Health ◽  
Coagulation Factor ◽  
Peak Height ◽  
Health Study ◽  
Cardiovascular Health Study ◽  
Strong Linkage Disequilibrium ◽  
Factor Xii ◽  
Endogenous Thrombin Potential

Background: Currently, a majority of evidence suggests that the tissue factor-mediated extrinsic coagulation pathway is most important in generating thrombin in vivo , although accumulating evidence implicates the coagulation factor XII/factor XI-mediated intrinsic system as well. The endogenous thrombin potential (ETP), a measure of thrombin generation, is gaining importance in assessing risk of hemorrhage and thrombosis, but genetic determinants of ETP have not been investigated in population-based studies. Methods: Total ETP (ETP T ) was measured in citrated plasma by TechnoClone TGA assay in a random subset of Cardiovascular Health Study (CHS) participants ( n =1,000). Extrinsic pathway ETP (ETP EX ) was measured by the addition of anti-FXIa antibody to the assay; Intrinsic pathway ETP (ETP IN ) was calculated by subtracting ETP EX from ETP T . Genotyping was performed in the NHLBI’s Candidate-gene Association Resource (CARe) Study on 49,320 SNPs using Illumina’s custom IBCv2 genotyping array in 866 participants. Associations of SNPs with age- and sex-adjusted ETP phenotypes were evaluated by linear regression using PLINK; results were considered statistically significant if p≤ 2x 10 -6 . Results: Two SNPs on the IBC array were significantly associated with lower ETP T : rs2545801 (β=-45.87 nM ± 7.3 nM; p=5.7x10 -10 ; minor allele frequency (MAF) =0.24), and rs1801020 (β=-45.76 nM ± 7.3 nM; p=7.4x10 -10 ; MAF= 0.23). Both SNPs are located in the coagulation factor XII gene ( F12 ); rs2545801is located in a 5’ region upstream of the transcriptional start site, and rs1801020 in a 5’ untranslated region; the SNPs are in strong linkage disequilibrium (LD) (r 2 = 0.92). Each SNP had a significant effect on ETP thrombin peak height. The mean (SD) thrombin peak heights were 408 nM (152nM) vs.523 nM (123 nM) and 404 nM (147 nM) vs. 523 nM (123 nM) for those homozygous for the minor and major alleles of rs2545801 and rs1801020, respectively. Addition of corn trypsin inhibitor (CTI; an inhibitor of activated FXII (FXIIa)) had no effect on ETP, suggesting that the F12 SNPs may affect the FXII-dependent generation of activated FXI (FXIa) in vivo. Therefore, we inhibited FXIa by the addition of anti-FXIa antibody, which resulted in a large and variable effect on ETP thrombin peak height. Consistent with these observations, analyses of SNPs associated with ETP IN revealed increased significance of the p-values for the F12 SNPs (p=1.40 x 10 -15 and p=1.60 x 10 -14 for rs1801020 and rs254580, respectively). Conclusion: These data support the importance of F12 SNPs on thrombin generation, and suggest that these SNPs affect the amount of FXIa generated in vivo . Additional work is needed to confirm this hypothesis, and to examine relationships of these biomarkers and SNPs with thrombotic diseases.

Valence electron spectroscopy of inhomogeneous media

1992 ◽  
Vol 50 (2) ◽  
pp. 1150-1151
Author(s):  
A. Howie ◽  
D.W. McComb
Keyword(s):  
Specific Gravity ◽  
Loss Function ◽  
Electron Spectroscopy ◽  
Valence Electron ◽  
Peak Height ◽  
Loss Functions ◽  
Loss Peak ◽  
High Energies ◽  
Valence Electron Density ◽  
Electron Microscopist

The bulk loss function Im(-l/ε (ω)), a well established tool for the interpretation of valence loss spectra, is being progressively adapted to the wide variety of inhomogeneous samples of interest to the electron microscopist. Proportionality between n, the local valence electron density, and ε-1 (Sellmeyer's equation) has sometimes been assumed but may not be valid even in homogeneous samples. Figs. 1 and 2 show the experimentally measured bulk loss functions for three pure silicates of different specific gravity ρ - quartz (ρ = 2.66), coesite (ρ = 2.93) and a zeolite (ρ = 1.79). Clearly, despite the substantial differences in density, the shift of the prominent loss peak is very small and far less than that predicted by scaling e for quartz with Sellmeyer's equation or even the somewhat smaller shift given by the Clausius-Mossotti (CM) relation which assumes proportionality between n (or ρ in this case) and (ε - 1)/(ε + 2). Both theories overestimate the rise in the peak height for coesite and underestimate the increase at high energies.

Thrombin generation in paediatric patients with congenital heart disease

2008 ◽  
Vol 28 (S 01) ◽  
pp. S61-S66 ◽  
Author(s):  
G. Cvirn ◽  
A. Rosenkranz ◽  
B. Leschnik ◽  
W. Raith ◽  
W. Muntean ◽  
...  
Keyword(s):  
Congenital Heart Disease ◽  
Heart Disease ◽  
Negative Correlation ◽  
Congenital Heart ◽  
Thrombin Generation ◽  
Significant Negative Correlation ◽  
Peak Height ◽  
Global Test ◽  
Paediatric Patients ◽  
Age Range

SummaryThrombin generation was studied in paediatric patients with congenital heart disease (CHD) undergoing cardiac surgery using the calibrated automated thrombography (CAT) in terms of the lag time until the onset of thrombin formation, time to thrombin peak maximum (TTP), endogenous thrombin potential (ETP), and thrombin peak height. The suitability to determine the coagulation status of these patients was investigated. Patients, material, methods: CAT data of 40 patients with CHD (age range from newborn to 18 years) were compared to data using standard coagulation parameters such as prothrombin (FII), antithrombin (AT), tissue factor pathway inhibitor (TFPI), prothrombin fragment 1.2 (F 1.2), thrombin-antithrombin (TAT), activated partial thromboplastin time (aPTT), and prothrombin time (PT). Results: A significant positive correlation was seen between ETP and FII (p < 0.01; r = 0.369), as well as between peak height and F II (p < 0.01; r = 0.483). A significant negative correlation was seen between ETP and TFPI values (p < 0.05; r = –0.225) while no significant correlation was seen between peak height and TFPI. A significant negative correlation was seen between F 1.2 generation and ETP (p < 0.05; r = –0.254) and between F 1.2 generation and peak height (p < 0.05; r = –0.236). No correlation was seen between AT and ETP or peak. Conclusions: CAT is a good global test reflecting procoagulatory and inhibitory factors of the haemostatic system in paediatric patients with CHD.

Validated Stability Indicating HPTLC Method for the Estimation of Amoxapine in Different Stress Conditions

2019 ◽  
Vol 15 (3) ◽  
pp. 273-279
Author(s):  
Shweta G. Rangari ◽  
Nishikant A. Raut ◽  
Pradip W. Dhore
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Degradation Products ◽  
Analysis Data ◽  
Peak Height ◽  
Good Resolution ◽  
Stability Indicating ◽  
Limit Of Quantitation ◽  
Wide Range ◽  
Hptlc Method

Background:The unstable and/or toxic degradation products may form due to degradation of drug which results into loss of therapeutic activity and lead to life threatening condition. Hence, it is important to establish the stability characteristics of drug in various conditions such as in temperature, light, oxidising agent and susceptibility across a wide range of pH values.Introduction:The aim of the proposed study was to develop simple, sensitive and economic stability indicating high performance thin layer chromatography (HPTLC) method for the quantification of Amoxapine in the presence of degradation products.Methods:Amoxapine and its degraded products were separated on precoated silica gel 60F254 TLC plates by using mobile phase comprising of methanol: toluene: ammonium acetate (6:3:1, v/v/v). The densitometric evaluation was carried out at 320 nm in reflectance/absorbance mode. The degradation products obtained as per ICH guidelines under acidic, basic and oxidative conditions have different Rf values 0.12, 0.26 and 0.6 indicating good resolution from each other and pure drug with Rf: 0.47. Amoxapine was found to be stable under neutral, thermal and photo conditions.Results:The method was validated as per ICH Q2 (R1) guidelines in terms of accuracy, precision, ruggedness, robustness and linearity. A good linear relationship between concentration and response (peak area and peak height) over the range of 80 ng/spot to 720 ng/spot was observed from regression analysis data showing correlation coefficient 0.991 and 0.994 for area and height, respectively. The limit of detection (LOD) and limit of quantitation (LOQ) for area were found to be 1.176 ng/mL and 3.565 ng/mL, whereas for height, 50.063 ng/mL and 151.707 ng/mL respectively.Conclusion:The statistical analysis confirmed the accuracy, precision and selectivity of the proposed method which can be effectively used for the analysis of amoxapine in the presence of degradation products.

Effect of cetyltrimethylammonium bromide on the electrochemiluminiscence and electrooxidation of luminol

1983 ◽  
Vol 48 (2) ◽  
pp. 477-483 ◽  
Author(s):  
Jan Lasovský ◽  
František Grambal
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Linear Sweep Voltammetry ◽  
Critical Micellar Concentration ◽  
Peak Height ◽  
Anodic Peak ◽  
Alkaline Solutions ◽  
Platinum Electrodes ◽  
Micellar Solutions ◽  
Linear Sweep ◽  
Low Concentrations

The electrooxidation of luminol in alkaline solutions in the presence of cetyltrimethylammonium bromide (I) was studied by linear sweep voltammetry on fixed and vibrating platinum electrodes. The presence of I in low concentrations (below the critical micellar concentration) brings about aggregation of the luminol, which is manifested by an increase in the anodic peak height and its shift towards lower potentials. In micellar solutions the peak height decreases owing to the slower diffusion of the bulkier micelles, the shift to lower potentials being preserved. The light-voltage curves correspond with the voltammetric curves, exhibiting identical shifts of the peak potentials in dependence on the concentration of the surfactant.

Development of the Snoek Anelastic Relaxation Correlated with Oxygen in β-Ti Alloys

2019 ◽  
Vol 298 ◽  
pp. 59-63 ◽  
Author(s):  
Zheng Cun Zhou ◽  
J. Du ◽  
S.Y. Gu ◽  
Y.J. Yan
Keyword(s):  
Internal Friction ◽  
Physical And Mechanical Properties ◽  
Peak Height ◽  
Relaxation Peak ◽  
Interstitial Oxygen ◽  
Internal Friction Peak ◽  
Β Phase ◽  
Ti Alloys ◽  
Interstitial Atoms ◽  
The Stability

The β-Ti alloys exhibit excellent shape memory effect and superelastic properties. The interstitial atoms in the alloys have important effect on their physical and mechanical properties. For the interstitial atoms, the internal friction technique can be used to detect their distributions and status in the alloys. The anelastic relaxation in β-Ti alloys is discussed in this paper. β-Ti alloys possesses bcc (body center body) structure. The oxygen (O) atoms in in the alloys is difficult to be removed. The O atoms located at the octahedral sites in the alloys will produce relaxation under cycle stress. In addition, the interaction between the interstitial atoms and substitute atoms, e.g., Nb-O,Ti-O can also produce relaxation. Therefore, the observed relaxational internal friction peak during the measuring of internal friction is widened. The widened multiple relaxation peak can be revolved into Debye,s elemental peaks in Ti-based alloys. The relaxation peak is associated with oxygen movements in lattices under the application of cycle stress and the interactions of oxygen-substitute atoms in metastable β phase (βM) phase for the water-cooled specimens and in the stable β (βS) phase for the as-sintered specimens. The damping peak height is not only associated with the interstitial oxygen, but also the stability and number of βM in the alloys.

Sign in / Sign up

Export Citation Format

Share Document