scholarly journals Determination of Retinol-Binding Protein in Serum by Kinetic Immunonephelometry with Polyethylene Glycol Pretreatment

1984 ◽  
Vol 21 (6) ◽  
pp. 484-487 ◽  
Author(s):  
M J Hallworth ◽  
Jacqueline Calvin ◽  
C P Price
Keyword(s):  
Polyethylene Glycol ◽  
Detection Limit ◽  
Binding Protein ◽  
Regression Line ◽  
Retinol Binding Protein ◽  
Serum Samples ◽  
Coefficients Of Variation ◽  
Method Yield ◽  
Scattering Material

This work describes the use of polyethylene glycol as a pretreatment reagent to remove endogenous light scattering material from serum samples prior to automated immunonephelometric analysis on a centrifugal analyser. An assay system for retinol-binding protein is described, which allows rapid (10 minutes) quantitation of retinol-binding protein in serum samples with a detection limit of 5 mg/L and between-assay coefficients of variation ranging from 2·9% to 4·0%. The assay range is 5–80 mg/L and accuracy comparisons with a Mancini single radial immunodiffusion method yield a regression line y=0·89x+0·52 ( r=0·98, n=22). The problem of analyte precipitation associated with use of pretreatment regimes is discussed.

Immunonephelometric determination of retinol-binding protein in serum and urine.

1983 ◽  
Vol 29 (5) ◽  
pp. 853-856 ◽  
Author(s):  
M T Parviainen ◽  
P Ylitalo
Keyword(s):  
Binding Protein ◽  
Retinol Binding Protein ◽  
Good Precision ◽  
Serum Samples ◽  
Detection Range ◽  
Analytical Recovery ◽  
Beta 2 Microglobulin ◽  
Urine Specimens ◽  
Serum And Urine

Abstract An immunonephelometric method developed for measurement of retinol-binding protein (RBP) in serum and urine can detect it in concentrations of about 30 micrograms/L, which is in the lower limit of its normal concentration in urine (range 0-0.56 mg/L; mean +/- SD 0.19 +/- 0.15; n = 44). Urinary RBP was increased (range 0.93-29.5 mg/L) in all of 25 urine specimens from 13 subjects being treated with aminoglycoside (tobramycin). Urinary excretion of RBP was correlated (r = 0.83) with the excretion of beta 2-microglobulin. The within-assay and day-to-day precision (CV) was determined over the detection range of 0.03-8 mg/L. Within these limits the corresponding CVs varied from 4 to 27% and from 8 to 30%, respectively. The method had fairly good precision within the optimal measuring range of approximately 0.4 to 4.5 mg/L for both urine and 20-fold diluted serum samples. For various RBP concentrations our analytical recovery was 89-114% of added RBP. Results by this method correlated well (r = 0.96, n = 24) with those by a radial immunodiffusion method.

Resonance Rayleigh Scattering Determination of Trace Hemin Basing on Aptamer-Modified Nanogold Catalysis of HAuCl4-Vitamine C

2013 ◽  
Vol 787 ◽  
pp. 400-403
Author(s):  
Jin Chao Dong ◽  
Ai Hui Liang ◽  
Zhi Liang Jiang
Keyword(s):  
Detection Limit ◽  
Rayleigh Scattering ◽  
Resonance Rayleigh Scattering ◽  
Serum Samples ◽  
Buffer Solution ◽  
Strong Resonance ◽  
Scattering Spectra ◽  
Vitamine C ◽  
Nanogold Catalysis

Hemin aptamer was used to modify gold nanoparticles (AuNPs) to obtain a stable aptamer-nanogold probe (AussDNA). In the condition of pH 8.0 Tris-HCl buffer solution containing 50mmol/L NaCl, the substrate chain of AussDNA was cracked by hemin to produce a short single-stranded DNA(ssDNA) and then further combined with hemin to form a stable hemin-ssDNA conjugate. The AuNPs released from AussDNA would be aggregated in the condition of 50mmol/L NaCl and exhibited a strong resonance Rayleigh scattering (RRS) peak at 368nm. Under the selected conditions, the increased RRS intensity (ΔI368nm) was linear to hemin concentration in the range of 5-750nmol/L, with a detection limit of 66 pmol/L. This RRS method was applied to determination of residual hemin in serum samples, with satisfactory results. The remnant AussDNA in the solution exhibited a strong catalytic activity on the gold particle reaction of HAuCl4-vitamine C (VC) that can be monitored by RRS technique at 368 nm. When the hemin concentration increased, the AussDNA decreased, the catalysis decreased, and the RRS intensity at 368nm decreased. The decreased RRS intensity ΔI368nmwas linear to the hemin concentration in the range of 1-200nmol/L, with a detection limit of 54 pmol/L. Accordingly, a sensitivity, selectivity, and simplicity new method of resonance Rayleigh scattering spectra to detect hemin using aptamer-modified nanogold as catalyst was established.

Direct solid-phase enzymoimmunoassay of testosterone in saliva.

1989 ◽  
Vol 35 (10) ◽  
pp. 2044-2047 ◽  
Author(s):  
K Howard ◽  
M Kane ◽  
A Madden ◽  
J P Gosling ◽  
P F Fottrell
Keyword(s):  
Detection Limit ◽  
Analytical Procedure ◽  
Solid Phase ◽  
Medical Applications ◽  
Microtiter Plates ◽  
Large Numbers ◽  
Coefficients Of Variation ◽  
Serial Sampling ◽  
Direct Solid

Abstract This competitive, solid-phase enzymoimmunoassay for testosterone in saliva is carried out on microtiter plates and involves no chromatographic or extraction steps. With an overnight incubation the detection limit of the assay is 230 fg per well (16.1 pmol/L). There was a good correlation (correlation coefficient 0.95) between testosterone concentrations measured with and without prior extraction of the saliva samples. Repeated assay of three control saliva samples containing a range of testosterone concentrations (200-1000 pmol/L) gave within- and between-assay coefficients of variation of 5.5-13.2%. The analytical procedure is simple and closely resembles already published procedures for the determination of progesterone and estrone (with extraction) in saliva. One person can assay 200 samples in 24 h and the assay is suitable for reproductive and sports medical applications, particularly for projects involving serial sampling and yielding large numbers of samples.

Determination of glutathione and glutathione disulfide in human whole blood using HPLC with coulometric detection: A comparison with fluorescence detection

2011 ◽  
Vol 76 (4) ◽  
pp. 277-294 ◽  
Author(s):  
Roman Kanďár ◽  
Pavla Žáková ◽  
Miroslava Marková ◽  
Halka Lotková ◽  
Otto Kučera ◽  
...  
Keyword(s):  
Detection Limit ◽  
Whole Blood ◽  
Trichloroacetic Acid ◽  
Signal To Noise Ratio ◽  
Glutathione Disulfide ◽  
Simple Method ◽  
Human Whole Blood ◽  
Coulometric Detection ◽  
Coefficients Of Variation

We describe a relatively simple method for the determination of glutathione (GSH) and glutathione disulfide (GSSG) in human whole blood. We have used an HPLC with coulometric electrochemical detection for the simultaneous measurement of GSH and GSSG. Diluted and filtered trichloroacetic acid extracts were injected directly into the HPLC system and were eluted isocratically on a Polaris 5u C18-A, 250 × 4.6 mm analytical column. Glutathione in samples extracted with trichloroacetic acid and diluted with 1.0 mMhydrochloric acid was stable at 4 °C for at least 8 h. The analytical performance of this method is satisfactory: the intra-assay and inter-assay coefficients of variation were below 10%. Quantitative recoveries from spiked whole blood samples were at intervals 91.6–97.6% for GSH and 85.0–104.4% for GSSG. The linear range is 5.0–2000.0 μmol/l, with a detection limit of 2.1 μmol/l (signal-to-noise ratio = 3) for GSH and 2.0–250.0 μmol/l, with a detection limit of 0.9 μmol/l for GSSG.

scholarly journals Highly specific radioimmunoassay for human insulin based on immune exclusion of all insulin precursors

1998 ◽  
Vol 44 (7) ◽  
pp. 1504-1513 ◽  
Author(s):  
Michelle Deberg ◽  
Paule Houssa ◽  
Bruce H Frank ◽  
Françoise Sodoyez-Goffaux ◽  
Jean-Claude Sodoyez
Keyword(s):  
Monoclonal Antibodies ◽  
Detection Limit ◽  
Affinity Constant ◽  
Serum Samples ◽  
C Peptide ◽  
Specific Radioimmunoassay ◽  
Coefficients Of Variation ◽  
Patients With Diabetes ◽  
A Chain ◽  
Immune Exclusion

Abstract We describe a rapid and simple insulin RIA in which proinsulin and conversion intermediates do not interfere. Three monoclonal antibodies (S1, S2, and S53) were selected for their specificity (directed, respectively, against the B10 region, the junction between A chain and C-peptide, and the junction between B chain and C-peptide), their affinity constant (∼1010 L/mol), and their interactive properties in mixture. S2 and S53 were able to bind simultaneously to the same proinsulin molecule, whereas neither could bind simultaneously with S1. Preincubation of serum samples with an excess of S2 resulted in capture of proinsulin and conversion intermediates modified at the junction between B chain and C-peptide into immune complexes that no longer reacted with S1. Similarly, preincubation with S53 prevented proinsulin and conversion intermediates modified at the junction between A chain and C-peptide from reacting with S1. Preincubation with an excess of both S2 and S53 left insulin as the sole reactant with S1. Thus, separation of insulin precursors from insulin by mutually exclusive antibodies is feasible, and on the basis of this new principle, a highly specific RIA for insulin was designed. The detection limit was 11 pmol/L, and the inter- and intraassay coefficients of variation were 11% and 5%, respectively. The potential of the assay for use in clinical studies was verified by application to serum samples from control subjects and patients with diabetes or insulinoma.

Radioimmunoassay for pregnancy-associated plasma protein A.

1982 ◽  
Vol 28 (1) ◽  
pp. 50-53 ◽  
Author(s):  
M J Sinosich ◽  
B Teisner ◽  
J Folkersen ◽  
D M Saunders ◽  
J G Grudzinskas
Keyword(s):  
Detection Limit ◽  
Amniotic Fluid ◽  
Plasma Protein ◽  
Early Pregnancy ◽  
Twin Pregnancy ◽  
Protein A ◽  
Trophoblastic Disease ◽  
Coefficients Of Variation ◽  
Highly Sensitive

Abstract A specific and highly sensitive radioimmunoassay for determination of pregnancy-associated plasma protein A in human serum is described. The minimum detection limit for this protein was 2.9 micrograms/L. The within- and between-assay coefficients of variation were 4.0 and 4.5%, respectively. The circulating protein was detected within 32 days of conception in eight normal pregnancies and within 21 days in a twin pregnancy. Circulating concentrations in the mother at term were consistently higher (10-fold) than in matched amniotic fluid; none was detected in the umbilical circulation. This protein was also detected in the circulation of patients with hydatiform mole. This assay will permit investigations into the clinical evaluation of measurements of the protein during early pregnancy and trophoblastic disease.

scholarly journals Rapid Assay of Trace Immunoglobulin M by a New Immunonanogold Resonance Scattering Spectral Probe

2008 ◽  
Vol 13 (4) ◽  
pp. 302-308 ◽  
Author(s):  
Zhiliang Jiang ◽  
Lili Wei ◽  
Mingjing Zou ◽  
Aihui Liang ◽  
Mianwu Meng
Keyword(s):  
Polyethylene Glycol ◽  
Detection Limit ◽  
Resonance Scattering ◽  
Immunoglobulin M ◽  
Serum Samples ◽  
Rapid Assay ◽  
Lower Detection Limit ◽  
Lower Detection ◽  
Polyethylene Glycol 6000

Nanogold, 8 nm in size, was used to label goat antihuman immunoglobulin M (GIgM) to obtain a new immunonanogold resonance scattering (RS) probe (Au-GIgG) for quantitation of trace immunoglobulin M (IgM). The Au-GIgG combined with IgM to form nanogold-labeled immunocomplex causes the RS intensity at 580 nm to be enhanced, in pH 4.49 KH2PO 4-Na2HPO4 buffer and in the presence of polyethylene glycol 6000. The enhanced RS intensity at 580 nm (ΔI580 nm) is proportional to the IgM concentration in the range of 1.5 to 2000 ng/mL, with a lower detection limit of 0.98 ng/mL. The immunonanogold RS assay was used to assay IgM in serum samples, with sensitivity, selectivity, and simplicity. ( Journal of Biomolecular Screening 2008:302-308)

scholarly journals Validity of Transcobalamin II-Based Radioassay for the Determination of Serum Vitamin B12 Concentrations

1980 ◽  
Vol 17 (6) ◽  
pp. 287-292 ◽  
Author(s):  
Gulielma Paltridge ◽  
Zbigniew Rudzki ◽  
Richard G Ryall
Keyword(s):  
Binding Protein ◽  
Serum Vitamin ◽  
Normal Serum ◽  
Microbiological Assay ◽  
Vitamin B ◽  
Serum Samples ◽  
Naturally Occurring ◽  
Protein Serum ◽  
Transcobalamin Ii

A valid radioassay for the estimation of serum vitamin B12 in the presence of naturally occurring vitamin B12 (= cobalamin) analogues can be operated if serum transcobalamin II (TC II) is used as the binding protein. Serum samples that gave diagnostically discrepant results when their vitamin B12 content was analysed (i) by a commercial radioassay known to be susceptible to interference from cobalamin analogues, and (ii) by microbiological assay, were further analysed by an alternative radioassay which uses the transcobalamins (principally TC II) of diluted normal serum as the assay binding protein. Concordance between the results from microbiological assay and the TC II-based radioassay was found in all cases. In an extended study over a three-year period, all routine serum samples sent for vitamin B12 analysis that had a vitamin B12 content of less than 320 ng/l by the TC II-based radioassay (reference range 200–850 ng/l) were reanalysed using an established microbiological method. Over 1000 samples were thus analysed. The data are presented to demonstrate the validity of the TC II-based radioassay results in this group of patients, serum samples from which are most likely to produce diagnostically erroneous vitamin B12 results when analysed by a radioassay that is less specific for cobalamins.

Analytical evaluation of the Dade Behring Dimension RxL automated N-Terminal proBNP (NT-proBNP) method and comparison with the Roche Elecsys 2010

2005 ◽  
Vol 43 (11) ◽  
Author(s):  
Francesca Di Serio ◽  
Vincenzo Ruggieri ◽  
Lucia Varraso ◽  
Rosalisa De Sario ◽  
Angela Mastrorilli ◽  
...  
Keyword(s):  
Detection Limit ◽  
Healthy Subjects ◽  
Effect Of Temperature ◽  
Serum Samples ◽  
Coefficients Of Variation ◽  
Sample Stability ◽  
The Matrix ◽  
Heparin Plasma ◽  
Roche Diagnostics ◽  
Age And Sex

AbstractMethods to quantify B-type natriuretic peptide (BNP) and N-terminal-propeptide (NT-proBNP) in plasma or serum samples are well established. We assessed the analytical performance of the Dimension RxL NT-proBNP method (Dade-Behring). Evaluation of different sample types was carried out. Controls and heparin plasma pools were used to determine the detection limit, precision, and linearity. Sample stability and the effect of interfering substances on the NT-proBNP concentrations were evaluated. Agreement between Dimension RxL and Elecsys 2010 (Roche Diagnostics) NT-proBNP methods was assessed. The influence of age and sex on NT-proBNP concentrations was evaluated in healthy subjects. Heparin plasma should be the matrix of choice. The detection limit was 2.0ng/L. The total imprecision was 2.6–3.6% for concentrations from 231 to 9471ng/L; mean NT-proBNP concentrations of 21 and 15ng/L were associated with coefficients of variation of 9.9% and 14.7%, respectively. The method was linear up to 32,650ng/L. There was no effect of temperature, freeze-thaw cycles and interfering substances. A bias was detected when Dimension RxL and Elecsys 2010 NT-proBNP methods were compared. Age and sex were significantly and independently related to NT-proBNP concentrations. The Dimension RxL NT-proBNP method, like the Elecsys 2010, is suitable for routine use in the diagnosis of heart failure.

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