A Novel Method For The Direct Determination Of Platelet-Associated IgG (PAIgG) Employing Rocket Immunoelectrophoresis (Laurell)

1981 ◽  
Author(s):  
T J Kunicki ◽  
S M Kristopeit ◽  
R H Aster
Keyword(s):  
Direct Determination ◽  
Human Platelets ◽  
Rabbit Antibody ◽  
Human Igg ◽  
Novel Method ◽  
The Mean ◽  
Triton X ◽  
Phosphate Buffered Saline ◽  
Indirect Assay

The diagnosis and management of immune thrombocytopenia requires an effective method for the quantitation of platelet- associated IgG (PAIgG). Although several methods have been recently devised for this purpose, the search continues for a method which will prove to be accurate and reproducible, and yet simple enough to be utilized by the general clinical hemostasis laboratory. We now describe the development of an assay for PAIgG which we believe satisfies these criteria.Human platelets were isolated by differential centrifugation, washed five times in Tris-HCl pH 7.4 or phosphate buffered saline pH 7.4, both containing 5mM EDTA, and disrupted in 0.1M sodium acetate buffer pH 5.0 containing 1% (v/v) Triton X-100. Rabbit antibody specific for γ chains of human IgG (purified IgG fraction from DAKO) was carbamylated such that its isoelectric point was decreased to roughly 5.0. Total PAIgG was measured by electrophoresis at pH 5.0 of Triton X-100 disrupted washed platelets against the carbamylated rabbit anti-human IgG (γ) in 1% agarose gels containing 0.5% Triton X-100.The mean total PAIgG for 8 normals, was 5.7 fg/platelet (range 4.9 to 7.0). This technique is applicable to the quantitation of alloantibodies bound to normal platelets (indirect assay) as well as the quantitation of PAIgG on platelets of individuals with immune thrombocytopenic states, such as ITP.

In-line single-phase extraction for direct determination of total iron in oils using CdTe quantum dots and a flow-batch system

2015 ◽  
Vol 7 (18) ◽  
pp. 7707-7714 ◽  
Author(s):  
Marcelo B. Lima ◽  
Stéfani Iury E. Andrade ◽  
Inakã S. Barreto ◽  
Mário César U. Araújo
Keyword(s):  
Quantum Dots ◽  
Single Phase ◽  
Direct Determination ◽  
Total Iron ◽  
Cdte Quantum Dots ◽  
Phase Extraction ◽  
Batch System ◽  
System P ◽  
Novel Method

In this work, a novel method for direct determination of total iron in viscous samples is presented.

A Rapid Method of Determining Ammonium in Water With a Univalent Cation Glass Electrode

1971 ◽  
Vol 28 (5) ◽  
pp. 759-764 ◽  
Author(s):  
Jan Barica
Keyword(s):  
Rapid Method ◽  
Direct Determination ◽  
Glass Electrode ◽  
Ammonium Ion ◽  
Mean Error ◽  
Univalent Cation ◽  
The Mean

The use of a univalent cation glass electrode for determining ammonium in water is described. The method enables direct determination of ammonium ion in concentrations above 0.5 mg/liter without any dilution or pretreatment of sample. A constant background of Na+ and K+ in samples is required, with concentration of potassium being lower than that of ammonium. For several types of natural and enriched waters with ammonium content up to 40 mg/liter NH4-N, the mean error by the method was ±4.9%.

LC/MS Method Using Cloud Point Extraction for the Determination of Permitted and Illegal Food Colors in Liquid, Semiliquid, and Solid Food Matrixes: Single-Laboratory Validation

2011 ◽  
Vol 94 (6) ◽  
pp. 1853-1862 ◽  
Author(s):  
Ebru Ates ◽  
Klaus Mittendorf ◽  
Hamide Senyuva
Keyword(s):  
Cloud Point ◽  
Cloud Point Extraction ◽  
Water Soluble ◽  
Sunset Yellow ◽  
Allura Red ◽  
The Mean ◽  
Triton X ◽  
Single Laboratory ◽  
Food Colors

Abstract A cloud point extraction method is reported using LC/MS for the determination of regulated water-soluble food colors (Allura Red, Sunset Yellow, erythrosine, and tartrazine) and banned fat-soluble synthetic azo dyes (Sudan I, II, III, and IV; Red B; 7B; Black B; Red G; Metanil Yellow; and Rhodamine B). The extraction of all 14 colors was carried out with cloud point extraction using the nonionic surfactant Triton X 114. Optimized conditions for cloud point extraction were 3% Triton X 114 (w/v), 0.1 M ammonium acetate, and heating at 50°C for 30 min. This approach proved effective in giving quantitative recoveries from a diverse range of food matrixes, and optimized LC gave baseline chromatographic separation for all colors including Sudan IV and Red B. Single-laboratory validation was performed with spiking into liquid matrixes (wine and homemade wine), semiliquid matrixes (sauce and homemade paprika paste), and solid matrixes (spice and homemade chili powder) using the respective blank matrixes for matrix-matched calibration. The LOQ values for water-soluble colors were in the range of 15–150 mg/kg, and for the fat-soluble colors, 0.1–1.5 mg/kg. The mean recovery values were in the range of 69.6–116.0% (except Allura Red and Sunset Yellow in wine, for which recoveries were lower). The mean RSDs for colors were in the range of 4.0–14.8%. A small survey was conducted of samples of confectionery products, dried fruits, wines, bitter sodas, juices, sauces, pastes, and spices, which demonstrated the applicability of the method to a diverse selection of real food samples. Allura Red was detected in strawberry jelly and Sunset Yellow in artificial saffron.

Cytoplasmic Mg2+ concentration in platelets: implications for determination of Ca2+ with aequorin

1988 ◽  
Vol 255 (4) ◽  
pp. H855-H859
Author(s):  
J. A. Ware ◽  
M. Smith ◽  
E. T. Fossel ◽  
E. W. Salzman
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
31P Nmr ◽  
Cell Types ◽  
Human Platelets ◽  
Null Point ◽  
The Mean ◽  
Different Cell Types

The concentration of cytoplasmic ionized Mg2+ ([Mg2+]i) varies considerably among different cell types. It has not been measured in platelets. Incorrect estimates of this value could markedly affect many intracellular investigations, including calibration of measurements of platelet cytoplasmic ionized Ca2+ concentration ([Ca2+]i) with the photoprotein aequorin and other Ca2+-sensitive probes. [Mg2+]i was measured in washed, gel-filtered human platelets suspended in modified Tyrode buffer by two methods: 31P-nuclear magnetic resonance (NMR) spectroscopy of intact platelets and null-point titration in platelets selectively permeabilized with digitonin. The 31P-NMR spectra demonstrated that the [Mg2+]i, as calculated from the chemical shift values of ATP resonances, was 0.23 +/- 0.02 (SD) mM in unstimulated platelets. The mean [Mg2+]i as determined by null-point titration was 0.3 +/- 0.1 mM (range: 0.1-0.6 mM). When this [Mg2+]i value was used to construct a Ca2+-calibration curve for aequorin, the indicated [Ca2+]i values in resting and stimulated platelets were lower than those obtained from curves based on previously assumed values for [Mg2+]i (1.0-1.25 mM). This finding largely resolves the discrepancy between resting [Ca2+]i as determined by aequorin or by quin2, fura-2, and indo-1.

scholarly journals Application of ion pair complexes to design novel potentiometric membrane sensors for direct determination of frusemide in pharmaceuticals

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Nagaraju Rajendraprasad ◽  
Kanakapura Basavaiah
Keyword(s):  
Limit Of Detection ◽  
Direct Determination ◽  
Standard Addition ◽  
Ion Pair ◽  
Bromocresol Green ◽  
Bromophenol Blue ◽  
Experimental Parameters ◽  
The Mean

Abstract Background Fabrication of two membrane sensors using two acidic indicators among sulphonthalein dyes, namely bromophenol blue (BPB) and bromocresol green (BCG), and their use as indicative electrodes for the quantification of frusemide (FUR) is presented. The ion pair complexes of FUR with BPB or BCG are used to prepare the membranes in THF solvent, PVC matrix and dibutyl phthalate (DBP) as plasticizer and subsequently to fabricate FUR-BPB (Sensor I) and FUR-BCG (Sensor II) sensors. Results Sensors I and II are employable to determine 2.4 × 10-5–2.4 × 10-3 mol/L FUR at operative pH of 3.71. The calibration curve between the potentials against the concentration of FUR yielded the slopes of 58.73 ± 1 and 57.66 ± 1 mV/decade, respectively, using Sensors I and II, and this confirmed the Nernstian behaviour. Satisfactory correlation was obtained between the measured potentials and FUR concentration with the proposed sensors, and this was revealed by regression coefficient values of 0.9987 and 0.9980 for Sensors I and II, respectively. The LOD (limit of detection) values were calculated and reported for both the sensors. The experimental parameters were optimised to yield acceptable characteristics of both the sensors in the context of performance. The role of excipients of tablets and interferences were assessed by standard addition protocol. The obtained results confirmed the ineffective role of excipients of tablets and foreign species used as interferents. Conclusion The designed sensors were validated to confirm the accurate, precise, robust and rugged functioning in determining FUR. The mean of recovered FUR, close to 100%, revealed the acceptable and effective functioning of the proposed sensors. Excellent results were obtained by FUR tablets’ analysis using both the sensors.

scholarly journals The formation of Ca++-dependent complexes of platelet membrane glycoproteins IIb and IIIa in solution as determined by crossed immunoelectrophoresis

Blood ◽  
1981 ◽  
Vol 58 (2) ◽  
pp. 268-278 ◽  
Author(s):  
TJ Kunicki ◽  
D Pidard ◽  
JP Rosa ◽  
AT Nurden
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Human Platelets ◽  
Tetraacetic Acid ◽  
Rabbit Antibody ◽  
Membrane Glycoproteins ◽  
Normal Platelet ◽  
Crossed Immunoelectrophoresis ◽  
Glycoprotein Antigen ◽  
Glycoprotein Iiia ◽  
Triton X

Triton X-100 soluble proteins from 125I-labeled human platelets were studied by crossed immunoelectrophoresis employing a multispecific rabbit antibody raised against whole normal platelets. Emphasis was placed upon an analysis of immunoprecipitates containing 125I-labeled major membrane glycoproteins, and in particular, a prominent immunoprecipitate containing a glycoprotein antigen (s) previously designated as protein 16. SDS-polyacrylamide gel electrophoresis of protein 16 precipitated by a monospecific alloantibody. IgG L . . . , confirmed the presence of both glycoproteins IIb and IIIa. 125I-IgG L . . . , at concentration below that capable of precipitating protein 16 by itself, bound specifically to the precipitate containing protein 16 produced by the multispecific rabbit antibody. No other precipitates formed by the rabbit antibody contained either glycoprotein IIb or IIIa. When platelet proteins, incubated with optimum concentrations of ethylenediamine tetraacetic acid (EDTA) or ethyleneglycol bis (B- aminoethylether) NN1-tetraacetic acid (EGTA), were electrophoresed against the rabbit antibody, previously unobserved immunoprecipitates that contained either free glycoprotein IIb or free glycoprotein IIIa were detected. Upon readdition of excess Ca++, but not Mg++, to the same protein samples, a single immunoprecipitate containing both glycoproteins was once again observed. It is thus demonstrated that glycoproteins IIb and IIIa can form Ca++-dependent complexes (protein 16) in Triton X-100 extracts of normal platelets. The potential significance of the reversible association of these glycoproteins to normal platelet function is discussed.

scholarly journals Characteristic Times for the Fermi–Ulam Model

2021 ◽  
Vol 31 (02) ◽  
pp. 2130004
Author(s):  
Joelson D. Veloso Hermes ◽  
Edson D. Leonel
Keyword(s):  
Fractal Dimension ◽  
Phase Space ◽  
Lyapunov Exponent ◽  
Direct Determination ◽  
Recurrence Time ◽  
Invariant Curves ◽  
Lyapunov Time ◽  
Normal Diffusion ◽  
The Mean

The mean Poincaré recurrence time as well as the Lyapunov time are measured for the Fermi–Ulam model. It is confirmed that the mean recurrence time is dependent on the size of the window chosen in the phase space where particles are allowed to return. The fractal dimension of the region is determined by the slope of the recurrence time against the size of the window and two numerical values are measured: (i) [Formula: see text] confirming normal diffusion for chaotic regions far from periodic domains and (ii) [Formula: see text] leading to anomalous diffusion measured inside islands of stability and invariant curves corresponding to regular orbits, a signature of local trapping of an ensemble of particles. The Lyapunov time is the inverse of the Lyapunov exponent. Therefore, the Lyapunov time is measured over different domains in the phase space through a direct determination of the Lyapunov exponent.

scholarly journals A symmetrical method to obtain shear moduli from microrheology

Soft Matter ◽  
2018 ◽  
Vol 14 (19) ◽  
pp. 3716-3723 ◽  
Author(s):  
Kengo Nishi ◽  
Maria L. Kilfoil ◽  
Christoph F. Schmidt ◽  
F. C. MacKintosh
Keyword(s):  
Elastic Moduli ◽  
Direct Determination ◽  
Analysis Method ◽  
Shear Moduli ◽  
Mean Squared Displacement ◽  
The Mean ◽  
Symmetrical Method ◽  
Probe Particles

Passive microrheology deduces shear elastic moduli from thermally fluctuating motion of probe particles. We introduce and test an analysis method for direct determination of these moduli from the mean-squared displacement of a probe.

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