Disparities in estimates of IgG bound to normal platelets

Blood ◽  
1986 ◽  
Vol 67 (1) ◽  
pp. 200-202 ◽  
Author(s):  
N Blumberg ◽  
D Masel ◽  
M Stoler
Keyword(s):  
Direct Measurement ◽  
Immunosorbent Assay ◽  
Competitive Binding ◽  
Enzyme Linked Immunosorbent Assay ◽  
Binding Assays ◽  
Competitive Assay ◽  
Standard Curve ◽  
Normal Platelet ◽  
Direct Binding ◽  
Competitive Binding Assays

Abstract Estimates of the number of IgG molecules bound to normal platelets have ranged from several hundred to several tens of thousands. The lower estimates were generated from direct binding assays and stoichiometric assumptions. The higher values derive from competitive binding assays, in which platelet-associated IgG (PAIgG) is calculated from a standard curve using soluble IgG standards. Using a kinetic-ELISA (enzyme-linked immunosorbent assay) antiglobulin assay, we measured normal platelet IgG to be 21,200 +/- 9,400 molecules per platelet when a competitive assay and soluble IgG standards were used. Direct measurement of bound antiglobulin by kinetic-ELISA and stoichiometric assumptions yielded a measurement of 259 +/- 117 IgG molecules per platelet. Soluble IgG and PAIgG are not comparable in their ability to bind anti-IgG. Disparities in estimates of normal PAIgG are probably due to methodological differences. The estimate most likely to be correct is several hundred IgG or less per normal platelet.

Disparities in estimates of IgG bound to normal platelets

Blood ◽  
1986 ◽  
Vol 67 (1) ◽  
pp. 200-202
Author(s):  
N Blumberg ◽  
D Masel ◽  
M Stoler
Keyword(s):  
Direct Measurement ◽  
Immunosorbent Assay ◽  
Competitive Binding ◽  
Enzyme Linked Immunosorbent Assay ◽  
Binding Assays ◽  
Competitive Assay ◽  
Standard Curve ◽  
Normal Platelet ◽  
Direct Binding ◽  
Competitive Binding Assays

Estimates of the number of IgG molecules bound to normal platelets have ranged from several hundred to several tens of thousands. The lower estimates were generated from direct binding assays and stoichiometric assumptions. The higher values derive from competitive binding assays, in which platelet-associated IgG (PAIgG) is calculated from a standard curve using soluble IgG standards. Using a kinetic-ELISA (enzyme-linked immunosorbent assay) antiglobulin assay, we measured normal platelet IgG to be 21,200 +/- 9,400 molecules per platelet when a competitive assay and soluble IgG standards were used. Direct measurement of bound antiglobulin by kinetic-ELISA and stoichiometric assumptions yielded a measurement of 259 +/- 117 IgG molecules per platelet. Soluble IgG and PAIgG are not comparable in their ability to bind anti-IgG. Disparities in estimates of normal PAIgG are probably due to methodological differences. The estimate most likely to be correct is several hundred IgG or less per normal platelet.

Model for competitive binding assays. Shape and location of the inhibition curves

1974 ◽  
Vol 46 (8) ◽  
pp. 1132-1135 ◽  
Author(s):  
Donald J. Laurence ◽  
Graeme. Wilkinson
Keyword(s):  
Competitive Binding ◽  
Binding Assays ◽  
Competitive Binding Assays

Enzyme-Linked Immunosorbent Assay for Microcystins in Blue-Green Algal Blooms

1990 ◽  
Vol 73 (3) ◽  
pp. 451-456 ◽  
Author(s):  
Fun S Chu ◽  
Xuan Huang ◽  
R D Wei
Keyword(s):  
Liquid Chromatography ◽  
Immunosorbent Assay ◽  
Algal Blooms ◽  
Ammonium Bicarbonate ◽  
Enzyme Linked Immunosorbent Assay ◽  
Standard Curve ◽  
Green Algal ◽  
Recovery Study ◽  
Minimum Detection Level ◽  
Elisa Plate

Abstract A direct competitive enzyme-linked immunosorbent assay (ELISA) for the freshwater blue-green algal toxin mlcrocystln (MCYST) In algae and water was developed. The assay Involves coating antl-MCYST-variant leuclne-arglnine (LR) antibody to the ELISA plate and the use of MCYST-LRperoxidase as the enzyme marker. The linear portion of the standard curve for MCYST in phosphate buffer containing saline (PBS) was 0.5-10.0 ng/mL (25-500 pg/assay). The minimum detection level for MCYST-LR was 0.20 ng/mL (10 pg/assay). Contaminated water could be directly used In the ELISA. The overall analytical recoveries for MCYST-LR added to water at levels of 1-20 ng/mL was 83.4%. For analysis of cellular MCYST, the toxin was first extracted from the algae with 0.1M ammonium bicarbonate, diluted with PBS to less than 0.5 mg dried algae/mL (<5.0 mg wet welght/mL) and directly used in the ELISA. C-18 reverse-phase Sep-Pak cartridges effectively adsorbed MCYST from the toxln-containlng solutions. The toxin could be recovered from the cartridge by elutlng with 60% methanol. Using this approach, an algae extract that was relatively free of MCYST was prepared and was used in a recovery study. The overall analytical recovery of MCYST added to the algae extract In the range of 0.25-20 ppm was 83% with a coefficient of variation of 11.9%. The detection limit for MCYST In dried algae was about 0.25-0.5 pg/g (0.25-0.5 ppm) lyophlllzed algae sample. This method was applied for the analysis of several naturally occurring algal blooms. Limited samples were also analyzed for MYCST by liquid chromatography. ELISA data were in general agreement with those obtainedby liquid chromatography. MCYST concentrations from 0.006 to 2.9 fig/g (6 to 2900 ppb) and from 26 to 5200 /ig/g (26 ppm to 5200 ppm) were found In water and algae (dried weight), respectively

scholarly journals Fibrinogen Hershey IV: A novel dysfibrinogen with a γV411I mutation in the integrin αIIbβ3 binding site

2008 ◽  
Vol 99 (06) ◽  
pp. 1008-1012 ◽  
Author(s):  
Veronica Flood ◽  
Hamid Al-Mondhiry ◽  
Chantelle Rein ◽  
Kristine Alexander ◽  
Rehana Lovely ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Biological Effects ◽  
Terminal Segment ◽  
Wild Type ◽  
Binding Assays ◽  
Normal Platelet ◽  
Platelet Receptor ◽  
Direct Binding ◽  
Aggregation Inhibition ◽  
Carboxyl Terminal

SummaryThe carboxyl terminal segment of the fibrinogen γ chain from γ408–4ll plays a crucial role in platelet aggregation via interactions with the platelet receptor αIIbβ3. We describe here the first naturally-occurring fibrinogen point mutation affecting this region and demonstrate its effects on platelet interactions. DNA sequencing was used to sequence the proband DNA, and platelet aggregation and direct binding assays were used to quantitate the biological effects of fibrinogen Hershey IV. The Hershey IV proband was found to be heterozygous for two mutations, γV411I and γR275C. Little difference in aggregation was seen when fibrinogen Hershey IV was compared to normal fibrinogen. However, less aggregation inhibition was observed using a competing synthetic dodecapeptide containing the V411I mutation as compared to the wild-type dodecapeptide. Purified fibrinogen Hershey IV also bound to purified platelet αIIbβ3 with a lower affinity than wild-type fibrinogen. These findings show that the γV411I mutation results in a decreased ability to bind platelets. In the heterozygous state, however, the available wild-type fibrinogen appears to be sufficient to support normal platelet aggregation.

scholarly journals Aflatoxin Plate Kit

2011 ◽  
Vol 94 (5) ◽  
pp. 1519-1530
Author(s):  
Arthur Trombley ◽  
Titan Fan ◽  
Robert LaBudde
Keyword(s):  
Immunosorbent Assay ◽  
Hplc Method ◽  
Aflatoxin Contamination ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rapid Testing ◽  
Total Aflatoxin ◽  
Standard Curve ◽  
Independent Laboratory ◽  
Test Kit

Abstract The level of total aflatoxin contamination was analyzed in naturally contaminated and spiked samples of corn and peanut using the Aflatoxin Plate Kit. This kit is an enzyme-linked immunosorbent assay (ELISA) suitable for rapid testing of grains and peanuts. The assay was evaluated for ruggedness and linearity of the standard curve. The test kit results were then statistically evaluated for accuracy, precision, and correlation to a validated HPLC method (AOAC 994.08). The results were verified by an independent laboratory.

scholarly journals Characterization of MK6240, a tau PET tracer, in autopsy brain tissue from Alzheimer’s disease cases

2020 ◽  
Author(s):  
Mona-Lisa Malarte ◽  
Agneta Nordberg ◽  
Laetitia Lemoine
Keyword(s):  
Brain Tissue ◽  
Binding Sites ◽  
First Generation ◽  
Competitive Binding ◽  
Binding Assays ◽  
Control Brain ◽  
Saturation Binding ◽  
Pet Tracer ◽  
Tau Pet ◽  
Competitive Binding Assays

Abstract Purpose MK6240 is a second-generation tau PET tracer designed to detect the neurofibrillary tangles in the brains of patients with Alzheimer’s disease (AD). The aim of the study was to characterize 3H-MK6240 in AD and control brain tissue and to compare its binding properties with those of first-generation tau PET tracers. Methods Saturation binding assays with 3H-MK6240 were carried out in the temporal and parietal cortices of AD brains to determine the maximum number of binding sites (Bmax) and the dissociation constants (Kd) at these sites. Competitive binding assays were carried out between 3H-MK6240 and unlabelled MK6240, AV-1451 (aka T807, flortaucipir) and THK5117, and between 3H-THK5351 and unlabelled MK6240. Regional binding studies with 3H-MK6240 were carried out in homogenates from six AD and seven control brains and, using autoradiography, on large frozen sections from two AD brains and one control brain. Results The saturation binding assays gave Bmax and Kd values of 59.2 fmol/mg and 0.32 nM in the temporal cortex and 154.7 fmol/mg and 0.15 nM in the parietal cortex. The competitive binding assays revealed two binding sites with affinities in the picomolar and nanomolar range shared by 3H-MK6240 and all the tested unlabelled compounds. There were no binding sites in common between 3H-THK5351 and unlabelled MK6240. Regional binding of 3H-MK6240 was significantly higher in AD brain tissue than in controls. Binding in brain tissue from AD patients with early-onset AD was significantly higher than in brain tissue from patients with late-onset AD. Binding of 3H-MK6240 was not observed in off-target regions. Autoradiography showed high regional cortical binding in the two AD brains and very low binding in the control brain. Conclusions 3H-MK6240 has a high binding affinity for tau deposits in AD brain tissue but also has different binding characteristics from those of the first-generation tau tracers. This confirms the complexity of tau tracer binding on tau deposits with different binding affinities for different binding sites.

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