Dilution of plasma with Tris buffer increases measured catecholamines in plasma.

Abstract A greatly simplified radioimmunoassay for bradykinin in human plasma is described. Current techniques require multiple chromatographic steps or extraction procedures with analytical recoveries of bradykinin of often less than 60%. We present a method in which bradykinin is separated from components of higher relative molecular mass (including kininogens) in a single step, by use of a column of Sephadex G-25 medium (PD-10). The mean analytical recovery of tritiated bradykinin added to plasma is 85.5% (SD, 3.5%). The sensitivity of this radioimmunoassay is 25 pg per assay tube, equivalent to 125 ng per liter of plasma. Twenty to 30 blood samples may be completely processed and assayed within 6 h. As determined with this technique, concentrations of bradykinin in plasma from apparently normal subjects ranged from 2.5 to 5.2 microgram/L (mean 4.2, SD 1.1 microgram/L); these values are consistent with previously reported normal values.

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Simplified radioimmunoassay of bradykinin in human plasma.

Clinical Chemistry ◽

10.1093/clinchem/26.3.429 ◽

1980 ◽

Vol 26 (3) ◽

pp. 429-432 ◽

Cited By ~ 3

Author(s):

P S Verma ◽

P E Lorenz ◽

G E Sander

Keyword(s):

Molecular Mass ◽

Human Plasma ◽

Normal Values ◽

Normal Subjects ◽

Single Step ◽

Relative Molecular Mass ◽

Blood Samples ◽

Analytical Recovery ◽

Assay Tube ◽

The Mean

Abstract A greatly simplified radioimmunoassay for bradykinin in human plasma is described. Current techniques require multiple chromatographic steps or extraction procedures with analytical recoveries of bradykinin of often less than 60%. We present a method in which bradykinin is separated from components of higher relative molecular mass (including kininogens) in a single step, by use of a column of Sephadex G-25 medium (PD-10). The mean analytical recovery of tritiated bradykinin added to plasma is 85.5% (SD, 3.5%). The sensitivity of this radioimmunoassay is 25 pg per assay tube, equivalent to 125 ng per liter of plasma. Twenty to 30 blood samples may be completely processed and assayed within 6 h. As determined with this technique, concentrations of bradykinin in plasma from apparently normal subjects ranged from 2.5 to 5.2 microgram/L (mean 4.2, SD 1.1 microgram/L); these values are consistent with previously reported normal values.

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Picogram Level Quantification of Grazoprevir and Elbasvir with Deuterated Internal Standards in Human Plasma Samples by LC–ESI-MS/MS

Indian Journal of Pharmaceutical Education and Research ◽

10.5530/ijper.50.4.14 ◽

2016 ◽

Vol 50 (4) ◽

pp. 612-619 ◽

Cited By ~ 2

Author(s):

Haritha Potluri ◽

Sreenivasa Rao Battula ◽

Sunandamma Yeturu

Keyword(s):

Human Plasma ◽

Plasma Samples ◽

Internal Standards ◽

Esi Ms ◽

Human Plasma Samples

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Simple extraction method and radioimmunoassay for somatostatin in human plasma.

Clinical Chemistry ◽

10.1093/clinchem/27.6.888 ◽

1981 ◽

Vol 27 (6) ◽

pp. 888-891 ◽

Cited By ~ 31

Author(s):

T L Peeters ◽

Y Depraetere ◽

G R Vantrappen

Keyword(s):

Human Plasma ◽

Plasma Proteins ◽

Extraction Method ◽

Plasma Samples ◽

Analytical Recovery ◽

Simple Extraction ◽

The Mean ◽

Radioimmunological Determination ◽

Dilution Curves

Abstract Interference by human plasma proteins in the radioimmunological determination of somatostatin was eliminated by subjecting plasma samples to acid--ethanol precipitation. The assay was performed on the lyophilized supernate from 300 microliters of human plasma, with reagents that are commercially available. Sensitivity was 2.6 pg, corresponding to 8.7 ng/L of plasma. The intra-assay CV was 8%; the inter-assay CV was 12% for a low (30 ng/L) and 15% for a high (100 ng/L) standard. The mean analytical recovery of exogenous somatostatin from plasma was 95%, and the standard synthetic cyclic somatostatin showed parallel dilution curves with extracted plasma samples. Neither gastrin HG-17 and HG-34, pentagastrin, secretin, glucagon, vasoactive intestinal polypeptide, substance P, nor pancreatic polypeptide interfered in the assay system. Mean immunoreactive somatostatin in 20 normal fasting subjects was 31.5 (SD 15.6) ng/L and ranged from 14 to 67 ng/L.

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Time-resolved immunofluorometric assay of total renin in plasma and follicular fluid

Clinical Chemistry ◽

10.1093/clinchem/40.1.74 ◽

1994 ◽

Vol 40 (1) ◽

pp. 74-79 ◽

Cited By ~ 3

Author(s):

I Matinlauri ◽

J U Eskola ◽

M Aalto ◽

P Koskinen ◽

K Irjala

Keyword(s):

Monoclonal Antibodies ◽

Detection Limit ◽

Human Plasma ◽

Follicular Fluid ◽

Reference Interval ◽

Plasma Samples ◽

Time Resolved ◽

Analytical Recovery ◽

Assay Precision ◽

Follicular Fluids

Abstract We developed a new time-resolved immunofluorometric assay (TR-IFMA) using two monoclonal antibodies for the total renin measurement in human plasma and follicular fluid. No conversion of prorenin to renin was needed because the assay detected both renin and prorenin. The detection limit of the assay was 10 ng/L and the linear range was 10-25,000 ng/L. Within-assay precision (CV) was 15-8% at renin concentrations of 50-12,200 ng/L. Between-assay precision was 19-3% at concentrations of 100-18,000 ng/L. Analytical recovery of added renin was 85-104% (n = 5) in plasma samples and 104-119% (n = 3) in follicular fluids. For plasma, the reference interval was 78-262 ng/L in men (n = 44) and 36-226 ng/L in women (n = 43).

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Bioanalytical method development and validation of simultaneous analysis of telmisartan and hydrochlorthiazide in human plasma using LC-MS/MS

International Journal of Bioassays ◽

10.21746/ijbio.2016.03.003 ◽

2016 ◽

Vol 5 (03) ◽

pp. 4862 ◽

Cited By ~ 1

Author(s):

Mathew George* ◽

Lincy Joseph ◽

Arpit Kumar Jain ◽

Anju V.

Keyword(s):

Human Plasma ◽

Retention Time ◽

High Performance ◽

Method Development ◽

Matrix Effects ◽

Solid Phase ◽

Internal Standard ◽

Assay Method ◽

Buffer System ◽

Internal Standards

A simple, sensitive, rapid and economic high performance thin layer chromatographic method and a mass spectroscopic assay method has been developed for the quantification of telmisartan and hydrochlorthiazide combination in human plasma. The internal standards and analytes were extracted from human plasma by solid-phase extraction with HLB Oasis1cc (30mg) catridges. The scanning and optimization for the samples are done using methanol: water (50:50). The samples were chromatographed using reverse phase chromatography with C-18 column of different manufacturers like Ascentis C18 (150×4. 6, 5µ) using the buffer system Acetonitrile: Buffer (80:20%v/v) which consist of 2±0. 1Mm ammonium format at a flow rate of 0. 7ml/min at a column oven temperature 35±10c. The internal standard used was hydrochlorthiazide13c1, d2 and telmisartand3. The extraction techniques include conditioning, loading, washing and elution, drying followed by reconstitution of the dried samples. The volume injected was 10µl with the retention time of 3-4 min for telmisartan, 1-2 min for hydrochlorthiazide and for the internal standards the retention time was 3-4 min for telmisartand3 and 1-2 min for hydrochlorthiazide c13d2. The rinsing solution was Acetonitrile: HPLC grade water in the ratio (50:50). The above developed method was validated using various parameters like selectivity and sensitivity, accuracy and precision, matrix effects, % recovery and various stability studies. The method was proved to be sensitive, accurate, precise and reproducible. The preparation showed high recovery for the quantitative determination of telmisartan and hydrochlorthiazide in human plasma.

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Development and validation of a selective SPR aptasensor for the detection of anticancer drug irinotecan in human plasma samples

Analytical and Bioanalytical Chemistry ◽

10.1007/s00216-020-03087-5 ◽

2021 ◽

Author(s):

Adelina Puscasu ◽

Martina Zanchetta ◽

Bianca Posocco ◽

David Bunka ◽

Stefano Tartaggia ◽

...

Keyword(s):

Human Plasma ◽

Anticancer Drug ◽

Plasma Samples ◽

Human Plasma Samples ◽

Development And Validation

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Radioimmunoassay of plasma ouabain in healthy and pregnant individuals

Journal of Endocrinology ◽

10.1677/joe.0.1650669 ◽

2000 ◽

Vol 165 (3) ◽

pp. 669-677 ◽

Cited By ~ 28

Author(s):

O Vakkuri ◽

SS Arnason ◽

A Pouta ◽

O Vuolteenaho ◽

J Leppaluoto

Keyword(s):

Pregnant Women ◽

Human Plasma ◽

High Performance ◽

Chemical Nature ◽

Solid Phase ◽

Plasma Concentrations ◽

First Trimester ◽

Plasma Samples ◽

Third Trimester ◽

Endogenous Substances

Ouabain was recently isolated from human plasma, bovine hypothalamus and bovine adrenal in attempts to identify endogenous substances inhibiting the cell membrane sodium pump. A number of radioimmunoassays have been developed in order to study the clinical significance of ouabain. The results have been controversial with regard to the presence and chemical nature of plasma ouabain-like immunoreactivity. We have now measured ouabain in healthy and pregnant individuals using solid-phase extraction of plasma samples followed by a new radioimmunoassay with the extraordinary sensitivity of at least 2 fmol/tube (5 pmol/l). Plasma extracts, a previously isolated human plasma ouabain-like compound and bovine hypothalamic inhibitory factor displaced the tracer in parallel and eluted identically with ouabain in high-performance liquid chromatography. Plasma ouabain immunoreactivity was found to be much lower than reported previously: 12.6+/-1.3 pmol/l in healthy men (mean+/-s.e., n=20) and 9.4+/-0.7 pmol/l in women (n=14). In pregnant women (n=28) plasma ouabain concentration was 16.3+/-4.0 pmol/l during the first trimester, 18.8+/-4.3 pmol/l during the second trimester and 24.3+/-4.0 pmol/l during the third trimester (all P<0.01 compared with non-pregnant women). Plasma ouabain 3-5 days after the delivery was 13.6+/-1.1 pmol/l (n=10, P<0.05-0.01 compared with second and third trimesters). The pregnancy-related changes in the plasma concentrations of ouabain resembled those of cortisol. Therefore cortisol was measured from the same plasma samples and a significant positive correlation was found (r=0.512, P=0.006). The similar profiles of plasma ouabain and cortisol during pregnancy and their rapid decreases postpartum are consistent with the adrenal cortical origin of ouabain and also show that the secretions of these hormones are possibly under the control of same factors.

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