Two-site time-resolved immunofluorometric assay of human insulin.

1986 ◽  
Vol 32 (4) ◽  
pp. 637-640 ◽  
Author(s):  
E Toivonen ◽  
I Hemmilä ◽  
J Marniemi ◽  
P N Jørgensen ◽  
J Zeuthen ◽  
...  
Keyword(s):  
Human Insulin ◽  
Fluorescence Enhancement ◽  
Microtiter Plate ◽  
The Other ◽  
Plasma Samples ◽  
Serum Samples ◽  
Time Resolved ◽  
Standard Curve ◽  
Sandwich Type ◽  
Plate Strip

Abstract We describe a two-site "sandwich"-type time-resolved immunofluorometric assay for human insulin, based on use of two monoclonal antibodies with different specificities. The first antibody is immobilized on the surface of microtiter plate strip wells, the other is labeled with Eu3+. Serum samples can be assayed with one incubation step; two incubation steps are required when plasma samples are assayed. After the immunoreactions are complete, the bound fraction of Eu3+-label is quantified by dissociating it in a fluorescence-enhancement solution and measuring its fluorescence with a fluorometer with time-resolution. The sensitivity of the assay is 0.24 micro-int. units/mL. The standard curve is linear from 0.24 to 2400 micro-int. units/mL.

Time-resolved immunofluorometric assay for the ovarian carcinoma-associated antigenic determinant CA 125 in serum.

1987 ◽  
Vol 33 (12) ◽  
pp. 2191-2194 ◽  
Author(s):  
O C Boerman ◽  
C M Thomas ◽  
M F Segers ◽  
P Kenemans ◽  
T Lövgren ◽  
...  
Keyword(s):  
Ovarian Carcinoma ◽  
Antigenic Determinant ◽  
Fluorescence Enhancement ◽  
Ca 125 ◽  
Serum Samples ◽  
Measuring Range ◽  
Time Resolved ◽  
Europium Chelate ◽  
Analytical Range ◽  
Automated Procedures

Abstract A time-resolved immunofluorometric assay (IFMA) is described for quantifying the ovarian carcinoma-associated antigenic determinant CA 125 in human serum. Monoclonal antibody to CA 125 is immobilized onto a microtiter well, and the same antibody labeled with a europium chelate is used as a tracer. After the immunoreaction the bound portion of the labeled antibody is quantified by dissociating the Eu3+ in a fluorescence-enhancement solution and measuring its fluorescence with a time-resolved fluorometer. The detection limit of the IFMA is 1.5 arb. units/mL, being about the same as that of a commercially available immunoradiometric assay (IRMA) for CA 125 (1.4 arb. units/mL). The analytical range of the IFMA extends to 2000 arb. units/mL, whereas the range of the IRMA is 500 arb. units/mL. For 29 serum samples from ovarian-cancer patients measured simultaneously in the IFMA and IRMA, orthogonal regression analysis gave the equation CA 125 (IFMA) = 0.9937 CA 125 (IRMA) - 1.211 arb. units/mL (Syx = 6.8681, r = 0.9932). Apparently, the IFMA for CA 125 is a convenient alternative to the IRMA for CA 125 because of short counting times, the use of nonradioactive, stable reagents, and the much-extended measuring range. Additionally, the microtiter format should lend itself to more fully automated procedures in laboratories doing many such analyses.

Evaluation of a solid-phase enzyme immunoassay for insulin in human serum.

1979 ◽  
Vol 25 (7) ◽  
pp. 1306-1308 ◽  
Author(s):  
K Kato ◽  
Y Umeda ◽  
F Suzuki ◽  
D Hayashi ◽  
A Kosaka
Keyword(s):  
Human Serum ◽  
Enzyme Immunoassay ◽  
Human Insulin ◽  
Silicone Rubber ◽  
Solid Phase ◽  
Serum Samples ◽  
Serum Factors ◽  
Insulin In Serum ◽  
Coefficients Of Variation ◽  
Sandwich Type

Abstract We describe a "sandwich-type" enzyme immunoassay for insulin in serum, in which antibody Fab'-beta-D-galactosidase conjugate and an antibody-immobilized silicone rubber solid-phase are used. The interference by serum factors with the solid-phase enzyme immunoassay can now be removed by using a buffer containing gelatin. Serum samples of 50 microL can be analyzed by the enzyme immunoassay, which is as sensitive as radioimmunoassay for human insulin. Our results correlate well with those for radioimmunoassay (r = 0.97, slope = 0.92, y-intercept = 4.6 milli-int. units /L for 181 samples). Between-assay and within-assay coefficients of variation are less than 15% over the useful ranges of the assay (5--160 milli-int. units/L).

scholarly journals Degradation of serum microRNAs during transient storage of serum samples at 4℃

2017 ◽  
Vol 55 (1) ◽  
pp. 178-180 ◽  
Author(s):  
Toshiko Aiso ◽  
Shu Takigami ◽  
Akiko Yamaki ◽  
Hiroaki Ohnishi
Keyword(s):  
Extracellular Vesicles ◽  
Room Temperature ◽  
The Other ◽  
Transient Storage ◽  
Plasma Samples ◽  
Serum Samples ◽  
Prolonged Incubation ◽  
Circulating Micrornas ◽  
Non Invasive ◽  
Serum Micrornas

Background Numerous studies demonstrate the potential of circulating microRNAs as non-invasive biomarkers for several diseases. Circulating microRNAs are much more stable than mRNAs and remain largely intact even after prolonged incubation at room temperature. However, recent reports show that microRNAs in serum or plasma samples have diverse stabilities. The aim of this pilot study is to evaluate the stabilities of miR-92a, miR-122 and miR-145 in serum during transient storage at 4℃ before freezing. Methods Serum samples were stored for 24 h at 4℃, and then RNA was extracted from whole serum or extracellular vesicles in serum. Total Exosome Isolation Reagent (from serum) was used for the fractionation of extracellular vesicles. Reverse transcription and real-time PCR of microRNAs were performed using the TaqMan MicroRNA Assays for miR-92a, miR-122 and miR-145. Results MiR-122 and miR-145 were degraded rapidly in serum; the concentrations dropped to 35.9% ( P < 0.001) and 29.3% ( P < 0.0001), respectively. These microRNAs in extracellular vesicles exhibited similar instability; the concentrations were 52.2% ( P < 0.05) and 56.5% ( P < 0.01), respectively. On the other hand, no significant degradation of miR-92a was observed (whole serum: P = 0.052, extracellular vesicles: P = 0.196). Conclusions MiR-122 and miR-145 in serum are extremely unstable and could be degraded during transient storage of serum at 4℃ prior to freezing.

scholarly journals Time-resolved fluoroimmunoassay for bactericidal/permeability-increasing protein

1996 ◽  
Vol 5 (1) ◽  
pp. 47-50 ◽  
Author(s):  
J.-O. Häggblom ◽  
A. B. Jokilammi-Siltanen ◽  
H. Peuravuori ◽  
T. J. Nevalainen
Keyword(s):  
Human Serum ◽  
Polymorphonuclear Leukocytes ◽  
Antimicrobial Protein ◽  
Plasma Samples ◽  
Serum Samples ◽  
Time Resolved ◽  
Reactive Protein ◽  
The Mean ◽  
The Difference ◽  
Mean Concentration

Bactericidal/permeability-increasing protein (BPI) is a cationic antimicrobial protein produced by polymorphonuclear leukocytes, that specifically interacts with and kills Gram-negative bacteria. BPl competes with lipopolysaccharide-binding protein (LBP) secreted by liver cells into blood plasma for binding to lipopolysaccharide (LPS) and thus reduces the proinflammatory effects of LPS. We have developed a time-resolved fluoroimmunoassay for BPI and measured the concentration of BPI in human serum and plasma samples. The assay is based on a rabbit antibody against recombinant BPI. This antibody specifically adheres to polymorphonuclear leukocytes in immunostained human tissues. The difference in the serum concentration of BPI between unselected hospitalized patients with and without an infection was statistically significant. The mean concentration of BPI in serum samples was 28.3 μg/l (range 1.64–132, S.D. 26.8,n= 83). In contrast, there was no difference between the two groups in the BPI levels in plasma samples. For all individuals tested, BPI levels were consistently higher in plasma samples compared to the matched serum samples. The mean concentration of BPI in plasma samples was 52.3 μg/l (range 0.9–403, S.D. 60.6,n= 90). There was a positive correlation between the concentration of BPI and the white blood cell count as well as between the BPI concentration and C-reactive protein (CRP) in serum samples. In conclusion, the present study demonstrates that BPI can be quantified reliably by time-resolved fluoroimmunoassay in human serum samples.

Determination of thyrotropin in serum by time-resolved fluoroimmunoassay evaluated.

1985 ◽  
Vol 31 (10) ◽  
pp. 1706-1709 ◽  
Author(s):  
H L Kaihola ◽  
K Irjala ◽  
J Viikari ◽  
V Näntö
Keyword(s):  
Specific Activity ◽  
High Specific Activity ◽  
Reference Interval ◽  
Time Resolved ◽  
Standard Curve ◽  
Highly Sensitive ◽  
Wide Range ◽  
Sandwich Type ◽  
Serum Tsh

Abstract We evaluated a new, highly sensitive time-resolved fluoroimmunoassay for thyrotropin (TSH) in serum. This direct immunometric "sandwich"-type assay involves two monoclonal antibodies against TSH, one immobilized, the other labeled with europium. Extremely high specific activity of the label and the use of labeled antibody in large excess make the method sensitive enough to measure TSH values falling below the normal reference interval. The standard curve is nearly linear over a wide range of TSH concentrations (standard concentrations range from 0.25 to 324 milli-int. units/L). The lowest concentration detectable was 25 micro-int. units/L. The CV for the assay was less than 6% at 0.5 milli-int. unit/L or higher, 11.3% at 0.1 milli-int. unit/L. For a CV of 10% the lower limit of the working range would be around 0.1 milli-int. unit/L. The interassay CV was 6.7 to 11.8% for TSH concentrations of 0.31 to 19.6 milli-int. units/L. The 95% confidence interval for sera from 111 healthy persons was 0.6-3.8 (range 0.3-3.8) milli-int. units/L. For hyperthyroid patients and thyroid cancer patients treated with thyroxin after thyroidectomy, serum TSH values were all below the reference interval (most were less than 25 micro-int. units/L).

Double monoclonal time-resolved immunofluorometric assay of beta 2-microglobulin in serum

1990 ◽  
Vol 36 (11) ◽  
pp. 1961-1964 ◽  
Author(s):  
A Tienhaara ◽  
J U Eskola ◽  
V Näntö
Keyword(s):  
Serum Samples ◽  
Time Resolved ◽  
Assay Procedure ◽  
Analytical Recovery ◽  
Sandwich Type ◽  
Capture Antibody ◽  
Polyclonal Antisera ◽  
Europium Chelate ◽  
Beta 2 ◽  
Beta 2 Microglobulin

Abstract Previously reported immunochemical assays of beta 2-microglobulin (beta 2m) have usually been based on polyclonal antisera. We have developed a "sandwich"-type time-resolved immunofluorometric assay (TR-IFMA) for beta 2m in serum, based on two monoclonal antibodies against human beta 2m. Microtiter wells are coated with the capture antibody, and the tracer antibody is labeled with a europium chelate. In a simple and fast assay procedure, prediluted serum samples are incubated with the tracer for 1 h in the microtiter wells, after which the wells are washed and the fluorescence of Eu is measured. The mean analytical recovery was 101.8% and results by TR-IFMA showed a good linear correlation with those by an established radioimmunoassay. The analytical range of TR-IFMA is large and well suited for clinical purposes.

A Sensitive and Facile Assay for the Measurement of Activated Protein C Activity Levels in Vivo

1993 ◽  
Vol 69 (05) ◽  
pp. 441-447 ◽  
Author(s):  
Carolyn L Orthner ◽  
Billy Kolen ◽  
William N Drohan
Keyword(s):  
Protein C ◽  
Plasma Concentrations ◽  
Limited Proteolysis ◽  
Activated Protein C ◽  
Microtiter Plate ◽  
Reversible Inhibitor ◽  
Activity Levels ◽  
Standard Curve ◽  
Agarose Beads

SummaryActivated protein C (APC) is a serine protease which plays an important role as a naturally occurring antithrombotic enzyme. APC, which is formed by thrombin-catalyzed limited proteolysis of the zymogen protein C, functions as an anticoagulant by proteolytic inactivation of the coagulation cofactors VIIIa and Va. APC is inhibited by several members of the serpin family as well a by α2-macroglobulin. APC is being developed as a therapeutic for the prevention and treatment of thrombosis. We have developed an assay to quantify circulating levels of enzymatically active APC during its administration to patients, in healthy individuals, and in various disease states. This assay utilizes an EDTA-dependent anti-protein C monoclonal antibody (Mab) 7D7B10 to capture both APC and protein C from plasma, prepared from blood collected in an anticoagulant supplemented with the reversible inhibitor p-aminobenzamidine. Mab 7D7B10-derivatized agarose beads are added to the wells of a 96-well filtration plate, equilibrated with Tris-buffered saline, and incubated for 10 min with 200 μl of plasma. After washing, APC and protein C are eluted from the immunosorbent beads with a calcium-containing buffer into the wells of a 96-well microtiter plate containing antithrombin III (ATIII) and heparin. The amidolytic activity of APC is then measured on a kinetic plate reader following the addition of L-pyroglutamyl-L-prolyl-L-arginine-p-nitroanilide (S-2366) substrate.The rate of substrate hydrolysis was proportional to APC concentration over a 200-fold concentration range (5.0 to 1,000 ng/ml) when measured continuously over a 15 to 30 min time period. The coefficient of variation was 5.9% at 35 ng/ml and 8.8% at 350 ng/ml APC. The sensitivity of the assay could be increased by measuring the amount of color produced after longer incubation times in the endpoint mode. The measured APC activity levels were little affected by varying protein C or prothrombin over the extremes of 0 to 150% of normal plasma concentrations. By constructing the standard curve in protein C-deficient plasma, the concentration of APC activity in normal pooled plasma was determined to be 2.8 ng/ml (45 pM), which represents 0.08% of the protein C concentration. The assay was approximately 50-fold more sensitive than the identical assay, but using Mab-coated microtiter wells rather than immunosorbent beads as the capture step.

Immune responses of Texel sheep to excretory/secretory products of adult Haemonchus contortus

Parasitology ◽  
1994 ◽  
Vol 108 (3) ◽  
pp. 351-357 ◽  
Author(s):  
H. D. F. H. Schallig ◽  
M. A. W. van Leeuwen ◽  
W. M. L. Hendrikx
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Haemonchus Contortus ◽  
Lymphocyte Proliferation ◽  
The Other ◽  
Proliferation Index ◽  
Serum Samples ◽  
Immunoblotting Analysis ◽  
Molecular Weights ◽  
Secretory Products

SUMMARYThe excretory/secretory (E/S) products of adult Haemonchus contortus comprise of at least 15 polypeptides with molecular weights ranging from 10 to > 100 kDa. These E/S products induce an immune response in infected Texel sheep, as demonstrated by specific IgGI levels and a significant lymphocyte proliferation index. Moreover, immunoblotting analysis revealed that sera of primary H. contortus-infected sheep specifically recognize a 24 kDa E/S product. In addition, sera of challenged sheep react strongly with a 15 kDa E/S product. The other E/S products of H. contortus showed immunoreactivity with serum samples of Haemonchus-infected sheep as well as with samples of sheep harbouring other trichostrongylid infections. These cross-reacting epitopes are the main cause of the lack of specificity of an E/S material- based ELISA. This ELISA can differentiate Haemonchus infections from Nematodirus battus infections, but not from Ostertagia circumcincta or Trichostrongylus colubriformis infections.

Search for Melanoma Markers in Plasma and Serum Samples

2005 ◽  
Vol 11 (3) ◽  
pp. 353-360 ◽  
Author(s):  
Roberta Seraglia ◽  
Susanna Vogliardi ◽  
Graziella Allegri ◽  
Stefano Comai ◽  
Mario Lise ◽  
...  
Keyword(s):  
High Frequency ◽  
Healthy Subjects ◽  
Ionic Species ◽  
Low Molecular Weight ◽  
Ionization Mass ◽  
Plasma Samples ◽  
Serum Samples ◽  
Blood Samples ◽  
Melanoma Patients ◽  
Diagnostic Ions

Fourteen blood samples from patients with melanomas and 11 blood samples from healthy subjects were analyzed by matrix-assisted laser desorption/ionization mass spectrometry. The study focussed on species of low molecular weight, in the 800–5000 Da range, present in plasma and sera. While for healthy subjects plasma samples lead to the production of a higher number of ionic species, for melanoma patients a high number of diagnostic ions, present with high frequency and with quite high relative abundance, are present, in particular, in serum samples and, to a lesser extent, also in plasma. Since plasma samples are obtained more easily in comparison to sera, it is possible to suggest that plasma can also be used for these studies.

In Vitro Study of Antioxidant Activity of Serum and Plasma Samples As Well As Glutathione Exposed to Various Exogenous Stress Factors

2021 ◽  
Author(s):  
Małgorzata Olszowy-Tomczyk ◽  
Łukasz Paprotny ◽  
Agnieszka Celejewska ◽  
Dorota Szewczak ◽  
Dorota Wianowska
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Activity ◽  
Antioxidant Properties ◽  
In Vitro Study ◽  
Stress Factors ◽  
Plasma Samples ◽  
Serum Samples ◽  
Exogenous Stress

Abstract The imbalance between the production of Reactive Oxygen Species (ROS) and their sequestration promotes the formation of so-called oxidative stress conditions which are considered crucial in the aging process and development of many human diseases. Glutathione plays an essential role in the antioxidative barricade against ROS. Its role in the detoxification process of xenobiotics and carcinogen is also known. However, there are no comparative studies on the antioxidant properties of both biological samples and glutathione as well as the change in these properties as a result of exposure to various stress factors. This paper fills this gap comparing the antioxidant activity of serum and plasma samples of the known glutathione content with the activity of glutathione itself assessed by the different methods. In addition, it reveals a significant role of environmental xenobiotics in oxidative stress and differentiates the stress induced by different groups of drugs, among which the greatest one has been demonstrated for antiarrhythmic drugs and cytostatics. More importantly, it proves that human plasma is more resistant to stress factors and N-acetylcysteine clearly promotes the extension of antioxidant properties of both the plasma and serum samples. The latter conclusion is consistent with the implied preventive and/or supportive action of this drug against SARS-CoV-2.

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