scholarly journals Endogenous Thrombin Potential Peak Height Measurement

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

Mannitol estimation in biological fluids by gas-liquid chromatography of trimethylsilyl derivatives.

1980 ◽  
Vol 26 (3) ◽  
pp. 441-443 ◽  
Author(s):  
M F Laker ◽  
J N Mount
Keyword(s):  
Liquid Chromatography ◽  
Biological Fluids ◽  
Internal Standard ◽  
Peak Height ◽  
Gas Liquid Chromatography ◽  
Height Measurement ◽  
Standard Solution ◽  
Trimethylsilyl Derivatives

Abstract We describe a procedure for estimating mannitol concentrations in biological fluids. Samples are mixed with internal standard solution (alpha-methylglucose), deproteinized if necessary, desalted, and dried. Specimens are then derivatized by adding pyridine/bis(trimethylsilyl)acetamide/trimethylchlorosilane and heating at 60 degrees C for 30 min. Samples are chromatographed on a 275-cm column of 10% OV-17, operated at 190 degrees C, and quantitated by peak-height measurement. The technique is linear, accurate, precise, sensitive, and free from interference. It has been used to measure mannitol in plasma, urine, and bile.

Quantitative Estimation of Clinically Important Monosaccharides in Plasma by Rapid Thin Layer Chromatography

1978 ◽  
Vol 15 (1-6) ◽  
pp. 65-76 ◽  
Author(s):  
I. S. Menzies ◽  
J. N. Mount ◽  
M. J. Wheeler
Keyword(s):  
Present Method ◽  
Quantitative Estimation ◽  
Peak Height ◽  
Sample Volume ◽  
Thin Layers ◽  
The Other ◽  
Initial Sample ◽  
Height Measurement ◽  
Internal Marker ◽  
Layer Chromatography

Summary A method is described for the quantitative estimation of clinically important monosaccharides in plasma or whole blood by direct densitometry of chromatographically-separated zones on silica gel layers. Simple modifications of technique originally introduced to improve the reproducibility of paper chromatography have now been adapted for thin layers. The present method is based on peak height measurement with an internal marker correction. Galactose, fructose, D-xylose, and 3-O-methyl glucose can be estimated in addition to glucose, either singly or in combination, within three or four hours, using an initial sample volume of 0·5 ml. With reasonable experience and skill a coefficient of variation of 3 to 6 %, depending on sugar concentration, can be achieved without replication, and the limit of sensitivity is about 0·05 mmol/l. When the performance was compared with an automated glucose oxidase/peroxidase system for glucose and the recovery for the other monosaccharides was calculated, the results were satisfactory.

Peak Height Measurement System for Pulsed Laser Experiments

1973 ◽  
Vol 44 (8) ◽  
pp. 978-981 ◽  
Author(s):  
Robert L. Swofford ◽  
W. M. McClain
Keyword(s):  
Measurement System ◽  
Pulsed Laser ◽  
Peak Height ◽  
Height Measurement ◽  
Laser Experiments

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.

Improved Method for High Pressure Liquid Chromatographic Determination of Chlorophacinone in Mouse Tissue

1982 ◽  
Vol 65 (6) ◽  
pp. 1299-1301
Author(s):  
Joseph B Addison
Keyword(s):  
High Pressure ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Mouse Tissue ◽  
Height Measurement ◽  
Liquid Chromatograph ◽  
Order Of Magnitude ◽  
High Pressure Liquid Chromatograph ◽  
Liquid Chromatographic

Abstract A simplified method is described for the determination of chlorophacinone, 2-[(p-chlorophenyl)- phenylacetyl]-l,3-indandione, in homogenized mice. Chlorophacinone is extracted with acetonitrile. After Florisil cleanup, the extract is injected into a high pressure liquid chromatograph for reverse phase chromatography on a polar Lichrosorb NH2 (10 μm) column, with a mobile phase of acetonitrile-water (80 + 20). An injection containing 70 ng chlorophacinone produces 1/2 scale peaks at 254 nm with a full scale absorbance of 0.1 unit, an order of magnitude improvement over the sensitivity reported earlier with a 280 nm detector. Six homogenized mice samples and six spiked homogenized mice samples were quantitatively analyzed for trace levels of chlorophacinone by this method. Recoveries from spiked samples, as determined by peak height measurement, were >95%. Mean retention time for the chlorophacinone peaks in all samples was 6.05 ± 0.05 min. Chlorophacinone levels determined in homogenized whole mouse samples ranged from 0 to 63 ppm.

scholarly journals Quantitative Analysis of Lorazepam in Pharmaceutical Formulation Through FTIR Spectroscopy

2012 ◽  
Vol 9 (4) ◽  
pp. 2232-2238 ◽  
Author(s):  
Elaheh Konoz ◽  
Amir Hossein Mohsen Sarrafi ◽  
Marjaneh Samadizadeh ◽  
Samaneh Boreiri
Keyword(s):  
Limit Of Detection ◽  
Direct Determination ◽  
Good Alternative ◽  
Peak Height ◽  
Pharmaceutical Products ◽  
Height Measurement ◽  
Line Extraction ◽  
Relative Standard ◽  
Standard Solution

A Fourier transform infrared (FTIR) spectrophotometric method was development for the rapid, direct measurement of lorazepam in different pharmaceutical products. The method involves the off-line extraction of lorazepam with sonication and direct determination in the extract through peak height measurement in the 1704 cm-1using a baseline correction between 1850 and 1550 cm-1. For standardization an external calibration line established from standard solutions of lorazepam in chloroform were used. The method provides a limit of detection of 0.0030 mg per tablet (n=5), a relative standard deviation (RSD) of 2.65% for 5 independent measurement of standard solution at a concentration level of 1 mgg-1. Result obtained by FTIR agrees with those obtained by a reference methodology based on ultraviolet spectrometry and thus the developed procedure offers a good alternative for the determination of lorazepam in commercial products.

Mannitol estimation in biological fluids by gas-liquid chromatography of trimethylsilyl derivatives.

1980 ◽  
Vol 26 (3) ◽  
pp. 441-443 ◽  
Author(s):  
M F Laker ◽  
J N Mount
Keyword(s):  
Liquid Chromatography ◽  
Biological Fluids ◽  
Internal Standard ◽  
Peak Height ◽  
Gas Liquid Chromatography ◽  
Height Measurement ◽  
Standard Solution ◽  
Trimethylsilyl Derivatives

Abstract We describe a procedure for estimating mannitol concentrations in biological fluids. Samples are mixed with internal standard solution (alpha-methylglucose), deproteinized if necessary, desalted, and dried. Specimens are then derivatized by adding pyridine/bis(trimethylsilyl)acetamide/trimethylchlorosilane and heating at 60 degrees C for 30 min. Samples are chromatographed on a 275-cm column of 10% OV-17, operated at 190 degrees C, and quantitated by peak-height measurement. The technique is linear, accurate, precise, sensitive, and free from interference. It has been used to measure mannitol in plasma, urine, and bile.

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