Radioimmunoassay of bovine placental lactogen using recombinant and native preparations: determination of fetal concentrations across gestation

2007 ◽  
Vol 19 (7) ◽  
pp. 877 ◽  
Author(s):  
A. V. Alvarez-Oxiley ◽  
N. M. Sousa ◽  
J. L. Hornick ◽  
K. Touati ◽  
G. C. van der Weijden ◽  
...  
Keyword(s):  
Detection Limit ◽  
Minimum Detection Limit ◽  
Placental Lactogen ◽  
Plasma Samples ◽  
Serum Samples ◽  
Fetal Plasma ◽  
The Third ◽  
Fetal Serum ◽  
Bovine Fetal Serum

Concentrations of bovine placental lactogen (bPL) were determined in fetal plasma samples by twelve double-antibody competitive radioimmunoassay systems (RIA I–XII) based on either recombinant bPL (non-glycosylated) or native bPL (glycosylated). Both preparations were used as standard and tracer, and for primary antisera production. The minimum detection limit measured by these RIA varied from 0.02 to 0.6 ng bPL mL–1. The coefficients of correlation of different bPL RIA systems were up to 90% (P < 0.0001) when each RIA was tested against the average values of all twelve RIA systems. All developed RIA were used to investigate the incidence of different bPL isoforms in bovine fetal serum samples (n = 71). Fetal concentrations ranged from 11.8 to 35.7 ng mL–1 at the third month and from 1.1 to 13.5 ng mL–1 at the ninth month of gestation. They tended to decrease with advancing gestation. In general, those RIA systems that used recombinant bPL as the standard measured higher values than those using the native bPL preparation. These differences decreased toward the end of gestation (P < 0.05), suggesting a lower rate of glycosylation. Our results provide evidence of different glycosylated isoforms of bPL in fetal serum at different gestation periods.

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.

scholarly journals Microassay of amiodarone and desethylamiodarone in serum by capillary electrophoresis with head-column field-amplified sample stacking

1996 ◽  
Vol 42 (11) ◽  
pp. 1805-1811 ◽  
Author(s):  
C X Zhang ◽  
Y Aebi ◽  
W Thormann
Keyword(s):  
Capillary Electrophoresis ◽  
Detection Limit ◽  
Linear Response ◽  
Separation Efficiency ◽  
Operating Costs ◽  
Serum Samples ◽  
Sample Stacking ◽  
Liquid Handling ◽  
High Separation

Abstract Binary-system capillary electrophoresis (CE) with head-column field-amplified sample stacking permits determination of amiodarone and desethylamiodarone in 20-microL serum samples. The assay is characterized by a detection limit for both compounds of 80 nmol/L and by excellent linear response over the recommended therapeutic range for amiodarone (1.5-4 mumol/L). Intra- and interday reproducibilities (CVs) between 3% and 6% and run times of approximately 10 min are comparable with those for conventional HPLC. Besides excellent sensitivity, attractive features of the assay include low operating costs, high separation efficiency, rapid drug extraction, consumption of almost negligible amounts of organic solvents, and simple operation. If appropriate microvessels and liquid-handling facilities are available, the same assay can be performed with 2 microL of serum, and if the serum is not diluted but rather is concentrated during extraction, &lt; 1 nmol/L of amiodarone can be detected.

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.

Spectrofluorimetric Determination of Bilirubin Using Enoxacine-Terbium Probe

2014 ◽  
Vol 556-562 ◽  
pp. 421-424 ◽  
Author(s):  
Wei Wei Bian
Keyword(s):  
Detection Limit ◽  
Fluorescence Intensity ◽  
Trace Amount ◽  
Optimum Conditions ◽  
Serum Samples ◽  
Buffer Solution ◽  
Spectrofluorimetric Method ◽  
Spectrofluorimetric Determination ◽  
Terbium Ion

A new spectrofluorimetric method was developed for determination of trace amount of bilirubin. Using enoxacine–terbium ion as a fluorescent probe, in the buffer solution of pH=5.8, BR can remarkably reduce the fluorescence intensity of the ENX-Tb3+ complex at λ=545nm and the reduced fluorescence intensity of Tb3+ ion is in proportion to the concentration of BR. Optimum conditions for the determination of BR were also investigated. The linear range and detection limit for the determination of BR are 1.0×10-7～4.5×10-6mol/L and 8.1×10-8mol/L. This method is simple, practical and can be successfully applied to assess BR in serum samples.

scholarly journals Determination of Haptoglobin in Bovine Serum using Polyclonal and Monoclonal Anti-human Haptoglobin Antibodies

2010 ◽  
Vol 79 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Paulina Jawor ◽  
Tadeusz Stefaniak ◽  
Iwona Kątnik-Prastowska
Keyword(s):  
Monoclonal Antibody ◽  
Detection Limit ◽  
Bovine Serum ◽  
Solid Phase ◽  
Low Cost ◽  
Reference Method ◽  
Serum Samples ◽  
Incubation Periods ◽  
Short Time

Two ELISA procedures to determine haptoglobin (Hp) in bovine serum were developed. Equine haemoglobin was used as the solid phase. Self-developed goat polyclonal antibody (variant I) and monoclonal antibody (variant II) raised against human Hp were used. The results were compared with the guaiacol method. High correlation was found (r = 0.96 and r = 0.90, respectively) based on the results of 548 bovine serum samples, of which 357 were from clinically healthy cows and 191 from cows and calves monitored during treatment for the most common diseases. The Hp detection limit of ELISA using polyclonal Ab was 0.1 mg/l and using MoAb 0.21 mg/l. The addition of 2% PEG 6000 at the antibody-binding steps enabled major shortening of the incubation periods. The relatively short time, low cost of reagents, and high correlation with the reference method support the use of these ELISA variants in bovine diagnostics.

Spectrophotometric Determination of Cyanoglucosides in Cassava

1984 ◽  
Vol 67 (3) ◽  
pp. 641-643 ◽  
Author(s):  
Bala Nambisan ◽  
Sukumaran Sundaresan
Keyword(s):  
Detection Limit ◽  
Sodium Hydroxide ◽  
Spectrophotometric Determination ◽  
Phosphate Buffer ◽  
Barbituric Acid ◽  
New Method ◽  
Minimum Detection Limit ◽  
Rapid Inactivation ◽  
Chloramine T

Abstract A new method is reported for determination of cyanoglucosides in cassava. The method is simple, rapid, and sensitive. Ten g cassava tuber is homogenized with warm (65–70°C) 80% ethanol (1 + 6, w/v) to extract cyanoglucosides (CNG). The ethanol is evaporated, and an aliquot of the extract (0.1–0.2 mL) is incubated with added linamarase in pH 6.0 phosphate buffer for 15 min at 30°C. The reaction is stopped by adding 0.2N sodium hydroxide, the solution is neutralized, and cyanide is estimated by adding chloramine T and barbituric acid–pyridine reagent and measuring the absorbance at 570 nm. Complete CNG extraction and rapid inactivation of endogenous linamarase is possible with 80% ethanol. There is no interference from extractives in the linamarase reaction or in the estimation of cyanide. Recovery of added linamarin (as cyanide) is 98% by this assay. The minimum detection limit of cyanide in the assay is 0.1 μg/mL.

Ion-chromatographic determination of plasma oxalate reexamined

1993 ◽  
Vol 39 (3) ◽  
pp. 537-539 ◽  
Author(s):  
M Petrarulo ◽  
E Cerelli ◽  
M Marangella ◽  
F Maglienti ◽  
F Linari
Keyword(s):  
Detection Limit ◽  
Hydrochloric Acid ◽  
Signal To Noise Ratio ◽  
Sample Pretreatment ◽  
Chromatographic Determination ◽  
Plasma Samples ◽  
Signal To Noise ◽  
Analytical Recovery ◽  
Healthy Persons

Abstract This new procedure for determining oxalic acid in plasma is based on sample deproteinization with hydrochloric acid and acetonitrile and subsequent ion-chromatographic assay of the neutralized supernate. Sample pretreatment produces very clean samples, which ensures long column life. Mean analytical recovery of oxalate (5.0-10.0 mumol/L) added to plasma samples averaged 98.6 +/- 6.2%; imprecision (CV) was 5.2% (at 2.2 mumol/L) and the detection limit was 0.5 mumol/L at a signal-to-noise ratio of 5:1. Ascorbate to oxalate conversion was &lt; 0.2%, indicating that the procedure is free from ascorbate interference. Plasma oxalate concentrations, measured in samples from 31 healthy persons, ranged from 0.8 to 3.4 mumol/L (mean 1.89, SD 0.75 mumol/L), which agrees with results from indirect radioisotopic dilution methods.

scholarly journals Paraoxonase activity in the serum of peripartum dairy cows with different placental lactogen concentrations

2017 ◽  
Vol 38 (5) ◽  
pp. 3371
Author(s):  
Marina Menoncin Weschenfelder Rohenkohl ◽  
Matheus Gomes Lopes ◽  
Antônio Amaral Barbosa ◽  
Ana Rita Tavares Krause ◽  
Paula Montagner ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Transition Period ◽  
Placental Lactogen ◽  
Pon1 Activity ◽  
Serum Samples ◽  
Maternal Metabolism ◽  
Significant Difference ◽  
Peripartum Period ◽  
High Concentrations

The action of the bovine placental lactogen (bPL) hormone on maternal metabolism is still poorly known. Some markers, such as the acute phase protein paraoxonase (PON1), are used as indicators of liver function and help to determine the metabolic condition during the transition period in dairy cows. The aim of this study was to evaluate the activity of paraoxonase (PON1) in the serum of peripartum dairy cows with different levels of bPL. Based on the plasma bPL concentration, 18 cows were divided equally into three groups: LOW ( < 2,68 ng bPL mL-1), MEDIUM (2,68–2,80 ng bPL mL-1), and HIGH ( > 2,80 ng bPL mL-1). The experiment was conducted between 21 days prepartum and 28 days postpartum. Serum samples were collected during the experiment for the determination of bPL concentrations and PON1 activity. The bPL concentration was significantly different between the experimental groups (P ? 0,0001) and the days of serum collection (P ? 0,0001). In the prepartum dairy cows, the PON1 levels were different between the groups (P ? 0,05) and the days of serum collection (P ? 0,05). Cows with high bPL concentration had lower serum PON1 activity (P ? 0,05), while cows with low hormone levels had higher enzyme activity (P ? 0,05). In the postpartum period, there was a significant difference between the days of serum collection (P ? 0,0001) and the interaction between groups and collections (P ? 0,01). The group with high concentrations of bPL had lower levels of PON1 (P ? 0,01), while the group with low bPL maintained higher concentrations of PON1 (P ? 0,01). It was concluded that the cows with higher concentrations of bPL in the prepartum period present a reduction in the serum activity of the PON1 enzyme during the peripartum period.

Determination of Soluble Fibrin in Plasma by a Rapid and Quantitative Spectrophotometric Assay

1986 ◽  
Vol 55 (02) ◽  
pp. 189-193 ◽  
Author(s):  
B Wiman ◽  
M Rånby
Keyword(s):  
Detection Limit ◽  
Spectrophotometric Assay ◽  
Lag Phase ◽  
Chromogenic Substrate ◽  
Plasma Samples ◽  
Healthy Individuals ◽  
Soluble Fibrin ◽  
Standard Curve ◽  
Tissue Plasminogen

SummaryA rapid, sensitive and quantitative spectrophotometric assay of soluble fibrin in plasma samples has been developed. The method is based on the principle that fibrin stimulates the activation of plasminogen by tissue plasminogen activator (t-PA). A sample containing fibrin is incubated with t-PA, plasminogen and a plasmin-sensitive chromogenic substrate. An increase in absorbance which is dependent on the fibrin concentration in the sample is obtained. In plasma samples an initial lag-phase, due to the presence of alpha2-antiplasmin is observed. However, the change in A405 per square minute during the later part of the reaction was found to be proportional to the fibrin content and to generate linear standard curve intercepts at the origin. The detection limit of bathroxobin-digested fibrinogen added to plasma was about 5 nmol/L. Recovery experiments at 20 and 75 nmol/L levels in plasma samples from healthy individuals were excellent. The “within-run” variation (CV) was determined as 3.7%. The formation of fibrin after addition of minute amounts of thrombin to plasma could be monitored with the method. Plasma from 8 healthy individuals was found to contain about 9.2 ± 1.9 nmol/L fibrin. Plasma samples from 46 patients with a suspected haemostatic disturbance had higher levels of soluble fibrin (53 ± 62 nmol/L). Seven of the 46 samples had concentrations above 150 nmol/L.

Determination of dabigatran in plasma, serum, and urine samples: comparison of six methods

2015 ◽  
Vol 53 (8) ◽  
Author(s):  
Shanshan Du ◽  
Christel Weiss ◽  
Giese Christina ◽  
Sandra Krämer ◽  
Martin Wehling ◽  
...  
Keyword(s):  
Real Life ◽  
Urine Samples ◽  
Thrombin Inhibitor ◽  
Plasma Samples ◽  
Clotting Time ◽  
Serum Samples ◽  
Life Conditions ◽  
Serum And Urine ◽  
Serum And Urine Samples

AbstractAssessing the anticoagulant effect of dabigatran may be useful in certain clinical settings. When plasma sampling is not available, serum or urine samples may provide another option for dabigatran determinations.Dabigatran was assessed in patients on treatment under real-life conditions in plasma samples by four clotting time-based assays and in plasma, serum, and urine samples by two chromogenic substrate methods.The concentrations of dabigatran in patients’ plasma samples were not different for the Hemoclot test (106.8±89.4 ng/mL) and the ecarin clotting time (ECT, 109.5±74.5 ng/mL, p=0.58). Activated partial thromboplastin time and prothrombinase-induced clotting time showed low correlations with the other assays. Chromogenic assays measured similar concentrations as Hemoclot and ECT. For both chromogenic assays, the concentrations of dabigatran were about 70% lower in serum than in plasma samples (p<0.0001). The intra-class coefficient (ICC, Bland-Altman analysis) was strong comparing ECT, Hemoclot thrombin inhibitor (HTI) assay, and the two chromogenic assays (r=0.889–0.737). The ICC was low for comparisons of the chromogenic assays of serum vs. plasma values (ICC, 0.15 and 0.66). The ICC for the determination of dabigatran in urine samples by the two chromogenic assays (5641.6±4319.7 and 4730.0±3770.2 ng/mL) was 0.737.ECT, HTI, and chromogenic assays can be used to determine dabigatran in plasma samples from patients under real-life conditions. Chromogenic assays require further improvement to reliably measure dabigatran in serum samples. Dabigatran concentrations in urine samples can also be determined quantitatively.

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