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

1994 ◽  
Vol 40 (1) ◽  
pp. 74-79 ◽  
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).

scholarly journals Antigenic Change in Human Influenza A(H2N2) Viruses Detected by Using Human Plasma from Aged and Younger Adult Individuals

Viruses ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 978 ◽  
Author(s):  
Matsuzawa ◽  
Iwatsuki-Horimoto ◽  
Nishimoto ◽  
Abe ◽  
Fukuyama ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Human Plasma ◽  
Influenza A ◽  
Neutralizing Antibody ◽  
Plasma Samples ◽  
Human Influenza ◽  
Human Monoclonal Antibodies ◽  
Younger Adults ◽  
Antibody Titers ◽  
Antigenic Cartography

Human influenza A(H2N2) viruses emerged in 1957 and were replaced by A(H3N2) viruses in 1968. The antigenicity of human H2N2 viruses has been tested by using ferret antisera or mouse and human monoclonal antibodies. Here, we examined the antigenicity of human H2N2 viruses by using human plasma samples obtained from 50 aged individuals who were born between 1928 and 1933 and from 33 younger adult individuals who were born after 1962. The aged individuals possessed higher neutralization titers against H2N2 viruses isolated in 1957 and 1963 than those against H2N2 viruses isolated in 1968, whereas the younger adults who were born between 1962 and 1968 possessed higher neutralization titers against H2N2 viruses isolated in 1963 than those against other H2N2 viruses. Antigenic cartography revealed the antigenic changes that occurred in human H2N2 viruses during circulation in humans for 11 years, as detected by ferret antisera. These results show that even though aged individuals were likely exposed to more recent H2N2 viruses that are antigenically distinct from the earlier H2N2 viruses, they did not possess high neutralizing antibody titers to the more recent viruses, suggesting immunological imprinting of these individuals with the first H2N2 viruses they encountered and that this immunological imprinting lasts for over 50 years.

Highly sensitive enzyme immunoassay of proinsulin immunoreactivity with use of two monoclonal antibodies

1993 ◽  
Vol 39 (10) ◽  
pp. 2146-2150 ◽  
Author(s):  
L L Kjems ◽  
M E Røder ◽  
B Dinesen ◽  
S G Hartling ◽  
P N Jørgensen ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Detection Limit ◽  
Human Serum ◽  
Enzyme Immunoassay ◽  
Healthy Subjects ◽  
Sandwich Elisa ◽  
C Peptide ◽  
Peptide Antibody ◽  
Analytical Recovery ◽  
Highly Sensitive

Abstract A highly sensitive two-site sandwich ELISA measuring total proinsulin immunoreactive material in serum or plasma was developed. The assay was based on two monoclonal antibodies, an anti-C-peptide antibody bound to a microtest plate and a biotin-labeled anti-insulin antibody. The detection limit (3 SD above zero value) in buffer was 0.05 pmol/L, corresponding to 0.25 pmol/L in human serum (diluted 1:5). The linear calibrator range was 0.05-20 pmol/L. Interassay CVs were 4.7% at a median (range) of 2.3 pmol/L (1.4-2.8 pmol/L, n = 8), 6.7% at 5.1 pmol/L (3.3-8.0 pmol/L, n = 8), and 8.7% at 10.0 pmol/L (8-12 pmol/L, n = 10). Mean analytical recovery of added human proinsulin (hPI) (2, 5, and 10 pmol/L) to serum was 84% (range 68-128%, n = 9). Human insulin and human C-peptide did not cross-react at 5000 and 10,000 pmol/L, respectively. The four major proinsulin conversion intermediates reacted 65-99%: split(32-33)hPI 74%, des-(31,32)hPI 65%, split(65-66)hPI 78%, and des(64,65)hPI 99%. All serum values from 38 fasting healthy subjects were above the detection limit: median (range) 4.0 (2.1-12.6) pmol/L.

Thyrotroph function assessed by sensitive measurement of thyrotropin with three immunoradiometric assay kits: analytical evaluation and comparison with the thyroliberin stimulation test.

1988 ◽  
Vol 34 (3) ◽  
pp. 568-575 ◽  
Author(s):  
F H Wians ◽  
J M Jacobson ◽  
J Dev ◽  
J I Heald ◽  
G Ortiz
Keyword(s):  
Clinical Performance ◽  
Reference Interval ◽  
Stimulation Test ◽  
Analytical Sensitivity ◽  
Immunoradiometric Assay ◽  
Analytical Evaluation ◽  
Becton Dickinson ◽  
Analytical Recovery ◽  
Stimulation Tests ◽  
Assay Precision

Abstract We evaluated the analytical and clinical performance of three "sensitive" immunoradiometric assay (IRMA) kits (Tandem-R TSH HS, Hybritech, Inc.; EchoClonal TSH, Bio-Rad; Coat-A-Count TSH IRMA, Diagnostic Products Corp.) for measurement of thyrotropin (TSH) and compared their performance against a "regular" IRMA (ARIA-HT, Becton-Dickinson) to determine whether these assays might eliminate the need to perform the thyroliberin (TRF) stimulation test. We concluded that the Tandem and EchoClonal kits may obviate the need to perform TRF stimulation tests in some patients. Using only the basal TSH concentration to predict the TSH response to TRF, we found all three sensitive TSH assays to be useful for detecting abnormal thyrotroph function. Dose-response, linearity, analytical recovery, and specificity were acceptable for all kits, but intra-assay precision at very low TSH concentrations and analytical sensitivity differed considerably among the kits. Using the EchoClonal assay, we established a normal reference interval for TSH of 0.4-4.6 milli-int. units/L.

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

1987 ◽  
Vol 33 (3) ◽  
pp. 408-411 ◽  
Author(s):  
J L Cuche ◽  
F Selz ◽  
G Ruget ◽  
M Gentil ◽  
C Gaudin
Keyword(s):  
Molecular Mass ◽  
Human Plasma ◽  
Tris Buffer ◽  
Plasma Samples ◽  
Internal Standards ◽  
Analytical Recovery ◽  
Proportional Decrease ◽  
Radioenzymatic Assays ◽  
Mass Component ◽  
Catecholamine Concentration

Abstract We investigated the effects of dilution of plasma samples on the measured concentrations of catecholamines. Diluting samples of human plasma 10-, 50-, and 100-fold with Tris buffer (100 mol/L, pH 8.6) improved analytical recovery of internal standards, suggesting that it decreases the commonly observed inhibition of methylation in radioenzymatic assays of catecholamines in plasma. However, the dilution is not associated with a proportional decrease in counted radioactivity. This extra amount of radioactivity, which is unlikely to be nonspecific in origin, accounts for a significant increase in the calculated catecholamine concentration. Tentatively, we suggest that Tris buffer releases both catecholamines and conjugated catecholamines bound to some unidentified low-molecular-mass component of plasma.

scholarly journals Simian Immunodeficiency Virus Engrafted with Human Immunodeficiency Virus Type 1 (HIV-1)-Specific Epitopes: Replication, Neutralization, and Survey of HIV-1-Positive Plasma

2006 ◽  
Vol 80 (6) ◽  
pp. 3030-3041 ◽  
Author(s):  
Eloisa Yuste ◽  
Hannah B. Sanford ◽  
Jill Carmody ◽  
Jacqueline Bixby ◽  
Susan Little ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Monoclonal Antibodies ◽  
Human Plasma ◽  
Plasma Sample ◽  
Plasma Samples ◽  
Neutralizing Activity ◽  
Immunodeficiency Virus ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACT To date, only a small number of anti-human immunodeficiency virus type 1 (HIV-1) monoclonal antibodies (MAbs) with relatively broad neutralizing activity have been isolated from infected individuals. Adequate techniques for defining how frequently antibodies of these specificities arise in HIV-infected people have been lacking, although it is generally assumed that such antibodies are rare. In order to create an epitope-specific neutralization assay, we introduced well-characterized HIV-1 epitopes into the heterologous context of simian immunodeficiency virus (SIV). Specifically, epitope recognition sequences for the 2F5, 4E10, and 447-52D anti-HIV-1 neutralizing monoclonal antibodies were introduced into the corresponding regions of SIVmac239 by site-directed mutagenesis. Variants with 2F5 or 4E10 recognition sequences in gp41 retained replication competence and were used for neutralization assays. The parental SIVmac239 and the neutralization-sensitive SIVmac316 were not neutralized by the 2F5 and 4E10 MAbs, nor were they neutralized significantly by any of the 96 HIV-1-positive human plasma samples that were tested. The SIV239-2F5 and SIV239-4E10 variants were specifically neutralized by the 2F5 and 4E10 MAbs, respectively, at concentrations within the range of what has been reported previously for HIV-1 primary isolates (J. M. Binley et al., J. Virol. 78:13232-13252, 2004). The SIV239-2F5 and SIV239-4E10 epitope-engrafted variants were used as biological screens for the presence of neutralizing activity of these specificities. None of the 92 HIV-1-positive human plasma samples that were tested exhibited significant neutralization of SIV239-2F5. One plasma sample exhibited >90% neutralization of SIV239-4E10, but this activity was not competed by a 4E10 target peptide and was not present in concentrated immunoglobulin G (IgG) or IgA fractions. We thus confirm by direct analysis that neutralizing activities of the 2F5 and 4E10 specificities are either rare among HIV-1-positive individuals or, if present, represent only a very small fraction of the total neutralizing activity in any given plasma sample. We further conclude that the structures of gp41 from SIVmac239 and HIV-1 are sufficiently similar such that epitopes engrafted into SIVmac239 can be readily recognized by the cognate anti-HIV-1 monoclonal antibodies.

scholarly journals Detection of in vitro and in vivo cleavage of high molecular weight kininogen in human plasma by immunoblotting with monoclonal antibodies

Blood ◽  
1986 ◽  
Vol 68 (2) ◽  
pp. 455-462 ◽  
Author(s):  
M Berrettini ◽  
B Lammle ◽  
T White ◽  
MJ Heeb ◽  
HP Schwarz ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Human Plasma ◽  
Heavy Chain ◽  
Light Chain ◽  
Plasma Samples ◽  
Single Chain ◽  
Sds Page ◽  
Immunoblotting Technique

Abstract Purified human high-mol-wt kininogen (HMWK), the cofactor of the contact phase of blood coagulation, migrated as a single band (approximately 110,000 mol wt) in a continuous buffer sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), but appeared as two separated bands (approximately 120,000 and 105,000 mol wt) when analyzed in a discontinuous buffer SDS-PAGE system. After elution from SDS polyacrylamide gels, each of the two bands showed coagulant activity. Six murine monoclonal antibodies (Mabs) against HMWK were produced and purified. In immunoblotting studies, three Mabs bound to the isolated alkylated heavy chain and one to the alkylated light chain of HMWK, whereas the remaining two bound only to the single-chain or unreduced two-chain molecule. None of the Mabs inhibited the clotting activity of HMWK or its binding to kaolin. Two of the Mabs, one directed against the light chain and one against the heavy chain, were used as specific probes to study HMWK in plasma samples using an immunoblotting technique. The anti-light chain Mab identified two distinct bands (approximately 120,000 and approximately 105,000 mol wt) in normal human plasma, but not in plasma from patients with hereditary HMWK deficiency. The anti-heavy chain Mab detected two additional bands (approximately 60,000 and approximately 54,000 mol wt) corresponding to low-mol-wt kininogen (LMWK) in normal plasma. A sensitive and specific quantitative immunoblotting assay of HMWK antigen in plasma was developed. Moreover, the immunoblotting technique with the anti-light chain Mab was used to detect the cleavage of HMWK in plasma samples after in vitro or in vivo activation of the contact system. The anti- light chain Mab demonstrated in vivo activation and cleavage of HMWK during an angioedema attack in a patient with hereditary angioedema and C1-inhibitor deficiency.

Improved determination of aluminum in serum and urine with use of a stabilized temperature platform furnace.

1982 ◽  
Vol 28 (10) ◽  
pp. 2139-2143 ◽  
Author(s):  
F Y Leung ◽  
A R Henderson
Keyword(s):  
Reference Interval ◽  
Matrix Interference ◽  
Linear Calibration ◽  
Standard Curve ◽  
Steady State Temperature ◽  
Analytical Recovery ◽  
Standard Additions ◽  
Assay Precision ◽  
Serum And Urine

Abstract This method for determining aluminum in serum and urine is essentially free from matrix interference and gives a linear response with concentration to at least 500 micrograms/l. Use of a stabilized temperature platform (L'vov platform, Perkin-Elmer Corp.) to approach a "steady-state" temperature, addition of matrix modifiers [especially Mg(NO3)2], and the use of peak area integration all helped substantially diminish spectral interference. With the platform furnace, serum protein concentrations as great as 260 g/L did not interfere with the determination of Al. The within- and between-assay precision (CV) was less than or equal to 3.5% and less than or equal to 7.4%, respectively. Analytical recovery of Al added to serum ranged between 95 and 101% throughout the linear calibration range (to 500 micrograms/L), either when measured directly from the standard curve or by the method of standard additions. The reference interval for Al in 28 healthy subjects was 2-14 micrograms/L (mean 6.5, SD 4.1 micrograms/L), and for 130 patients on hemodialysis, 20-550 micrograms/L (mean 87.5, SD 62.5 micrograms/L).

Simple extraction method and radioimmunoassay for somatostatin in human plasma.

1981 ◽  
Vol 27 (6) ◽  
pp. 888-891 ◽  
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.

Double-label time-resolved immunofluorometry of lutropin and follitropin in serum.

1987 ◽  
Vol 33 (12) ◽  
pp. 2281-2283 ◽  
Author(s):  
I Hemmilä ◽  
S Holttinen ◽  
K Pettersson ◽  
T Lövgren
Keyword(s):  
Monoclonal Antibodies ◽  
Detection Limit ◽  
Specific Antibody ◽  
Fluorescence Enhancement ◽  
Trioctylphosphine Oxide ◽  
Time Resolved ◽  
Double Label ◽  
Capture Antibody ◽  
Triton X ◽  
Label Time

Abstract We describe a procedure for the simultaneous immunofluorometric assay of lutropin and follitropin in human serum, based on the use of monoclonal antibodies and of the fluorescent lanthanides Eu3+ and Tb3+. The alpha-chain-specific antibody was used as a common capture antibody on the surfaces of microtitration strips. The anti-beta-follitropin antibody was labeled with Tb3+, the anti-beta-lutropin antibody with Eu3+. After the immunoreactions had taken place, the bound fractions of the labels were dissociated in a fluorescence enhancement solution of pivaloyltrifluoroacetone, trioctylphosphine oxide, and Triton X-100 surfactant. In this solution both lanthanides can be measured successively with a time-resolved fluorometer. The detection limit of the assay is 0.1 int. unit/L for lutropin and 1 int. unit/L for follitropin. Results correlated well with those by commercial immunofluorometric assays and radioimmunoassays.

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 < 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.

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