scholarly journals Development of a non-extracted ‘two-site’ immunoradiometric assay for corticotropin utilizing extreme amino- and carboxy-terminally directed antibodies

1984 ◽  
Vol 218 (3) ◽  
pp. 703-711 ◽  
Author(s):  
S C Hodgkinson ◽  
B Allolio ◽  
J Landon ◽  
P J Lowry
Keyword(s):  
Complex Formation ◽  
Confidence Interval ◽  
Immunoglobulin G ◽  
Solid Phase ◽  
High Sensitivity ◽  
Immunoradiometric Assay ◽  
Specific Effects ◽  
Rabbit Igg ◽  
Time Required ◽  
Wide Operating

The development of a ‘two-site’ immunoradiometric assay (i.r.m.a.) for the direct estimation of human corticotropin-(1-39)-peptide in plasma is described. The assay is based on the simultaneous addition of 125I-labelled sheep anti-(N-terminal corticotropin) IgG (immunoglobulin G) antibodies and rabbit anti-(C-terminal corticotropin) antiserum to standards and unknowns (0.5 ml) followed by 18h incubation. The use of solid-phase reagents was avoided in order to minimize non-specific effects and the time required for reactants to reach equilibrium. Instead, the separation of corticotropin-bound from free labelled antibody is achieved by the addition of sheep anti-(rabbit IgG) antiserum, which precipitates bound labelled antibody by complex-formation with rabbit anti-corticotropin antibodies, which are also hormone-bound. Several 125I-labelled sheep anti-(N-terminal corticotropin) IgG preparations were assessed in the i.r.m.a. Although each was derived from antisera raised to a thyroglobulin conjugate of synthetic corticotropin-(1-24)-peptide (Synacthen), purification of immunoglobulins before iodination by selective immunoadsorption resulted in preparations with distinct specificities which demonstrated marked differences in binding to intact human corticotropin-(1-39)-peptide. These preparations are compared in combination with two rabbit anti-(C-terminal corticotropin) antisera. A ‘two-site’ assay based on the use of 125I-labelled sheep anti-[corticotropin-(2-16)-peptide] IgG and rabbit anti-[corticotropin-(34-39)-peptide] antiserum was optimized, since steric inhibition of antibody binding was avoided with this combination and because the measurement of only intact human corticotropin-(1-39)-peptide and not fragments was assured by the use of terminal antibodies. This i.r.m.a. is characterized by rapid equilibration of reactants, a wide ‘operating range’ (the precision of dose estimates was less than 4% over the range 30-2200 pg/ml) and high sensitivity [8 pg of corticotropin/ml (95% confidence interval 3.7-12.0) (4 pg minimal detectable mass) can be detected directly in plasma].

scholarly journals A liquid-phase two-site immunoradiometric assay for human prolactin

1984 ◽  
Vol 217 (1) ◽  
pp. 273-279 ◽  
Author(s):  
S C Hodgkinson ◽  
J Landon ◽  
P J Lowry
Keyword(s):  
Solid Phase ◽  
High Sensitivity ◽  
Immunoradiometric Assay ◽  
Specific Antibodies ◽  
Simultaneous Addition ◽  
Operating Range ◽  
Specific Effects ◽  
Rabbit Igg ◽  
Human Prolactin ◽  
Time Required

The development of a ‘two-site’ immunoradiometric assay for human prolactin (hPrl) is described. The assay is based on the addition of radio-iodinated sheep anti-hPrl immunoglobulin G (IgG) and rabbit anti-hPrl serum to standards and unknowns followed by 3 h incubation. The use of solid phase reagents was avoided in order to minimize non-specific effects and the time required for reactants to reach equilibrium. Instead, the separation of hPrl-bound and free labelled antibody is achieved by the addition of sheep anti-(rabbit IgG) serum which precipitates bound labelled antibody by complex formation with rabbit anti-hPrl antibodies which are also hPrl-bound. Varying the order of addition of specific antibodies had a pronounced effect on the ‘operating range’ and sensitivity of resultant assays. This was attributed to competition between labelled and unlabelled antibodies for binding sites on the hPrl molecule. The immunoradiometric assay employing ‘simultaneous addition’ of specific antibodies was compared to a ‘simultaneous addition’ hPrl radioimmunoassay developed using the same sheep antiserum as that used to prepare the radioiodinated sheep anti-hPrl IgG. This immunoradiometric assay is characterized by rapid equilibration of reactants, a wide ‘operating range’ (the precision of dose estimates was less than 10% over the range 8-10000 mU/l), and high sensitivity (2.6 mU/l, 13 pg). In contrast, the hPrl radioimmunoassay required an incubation of 18 h, demonstrated a much reduced ‘operating range’ (the precision of dose estimates was less than 10% only over the range 25-1500 mU/l) and reduced sensitivity (9.8 mU/l, 49 pg).

scholarly journals Changes in Cytomegalovirus Seroprevalence Among U.S. Children Aged 1–5 Years: The National Health and Nutrition Examination Surveys

2020 ◽  
Author(s):  
Molly R Petersen ◽  
Eshan U Patel ◽  
Alison G Abraham ◽  
Thomas C Quinn ◽  
Aaron A R Tobian
Keyword(s):  
Confidence Interval ◽  
National Health ◽  
Immunoglobulin G ◽  
Igg Antibodies ◽  
Cross Sectional ◽  
Health And Nutrition ◽  
Prevalence Difference ◽  
The Cross ◽  
Us Children

Abstract Data from the cross-sectional National Health and Nutrition Examination Surveys (NHANES) indicate that the seroprevalence of cytomegalovirus immunoglobulin G (IgG) antibodies among US children aged 1–5 years was 20.7% (95% confidence interval [CI]: 14.0, 29.0) in 2011–2012 and 28.2% (95% CI: 23.1–34.0) in 2017–2018 (adjusted prevalence difference, +7.6% [95% CI: −.4, +15.6]).

scholarly journals A Single LC-MS/MS Analysis to Quantify CoA Biosynthetic Intermediates and Short-Chain Acyl CoAs

Metabolites ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 468
Author(s):  
Anthony E. Jones ◽  
Nataly J. Arias ◽  
Aracely Acevedo ◽  
Srinivasa T. Reddy ◽  
Ajit S. Divakaruni ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Sample Preparation ◽  
Biosynthetic Pathway ◽  
Solid Phase ◽  
High Sensitivity ◽  
Short Chain ◽  
Extraction Column ◽  
Chain Acyl ◽  
Precision And Accuracy ◽  
Mass Spectrometry Mass Spectrometry

Coenzyme A (CoA) is an essential cofactor for dozens of reactions in intermediary metabolism. Dysregulation of CoA synthesis or acyl CoA metabolism can result in metabolic or neurodegenerative disease. Although several methods use liquid chromatography coupled with mass spectrometry/mass spectrometry (LC-MS/MS) to quantify acyl CoA levels in biological samples, few allow for simultaneous measurement of intermediates in the CoA biosynthetic pathway. Here we describe a simple sample preparation and LC-MS/MS method that can measure both short-chain acyl CoAs and biosynthetic precursors of CoA. The method does not require use of a solid phase extraction column during sample preparation and exhibits high sensitivity, precision, and accuracy. It reproduces expected changes from known effectors of cellular CoA homeostasis and helps clarify the mechanism by which excess concentrations of etomoxir reduce intracellular CoA levels.

A new photometric method for oxygen consumption measurements in cell suspensions

1986 ◽  
Vol 61 (2) ◽  
pp. 449-455 ◽  
Author(s):  
W. Mueller-Klieser ◽  
R. Zander ◽  
P. Vaupel
Keyword(s):  
Volume Fraction ◽  
High Sensitivity ◽  
Cell Suspensions ◽  
Measuring System ◽  
Photometric Method ◽  
O2 Consumption ◽  
Physical Density ◽  
O2 Concentration ◽  
Consumption Rates ◽  
Time Required

A new technique is described for measuring O2 consumption rates and O2 concentrations in suspensions of respiring cells. Aliquots of a cell suspension kept in a special thermostated precision syringe are injected into the measuring system in defined time intervals. The O2 content of these samples is determined photometrically, as reported previously. The O2 consumption per cellular wet weight and/or per single cell can be calculated from the cell volume fraction, the physical density, the cell concentration in the suspension, and the time-dependent decline of the O2 concentration in the precision syringe. The minimum detectable amount of O2 is 0.1 microliter O2, which corresponds to 0.001 (vol/vol) of O2 if a 100-microliters sample of suspended cells is analyzed. Reproducibility of the O2 consumption measurement is 9% of the measured value. The advantages offered by this method are the straightforward calibration in absolute terms, the short time required for one analysis (2–6 min), a high sensitivity, the simultaneous determination of overall O2 concentration and O2 consumption rates in cell suspensions, and the great variability in the application.

Combustion Synthesis of La0.65Sr0.35MnO3 and its Sensing Properties for NO2

2016 ◽  
Vol 680 ◽  
pp. 208-211
Author(s):  
Lian Lian Wu ◽  
Qiang Li ◽  
Dan Yu Jiang ◽  
Jin Feng Xia
Keyword(s):  
Solid Phase ◽  
High Sensitivity ◽  
Combustion Method ◽  
Fast Response ◽  
Size Analysis ◽  
Phase Method ◽  
X Ray Diffraction ◽  
Ultrafine Structure ◽  
Nox Sensor ◽  
Solid Phase Method

In this paper, La0.65Sr0.35MnO3 (LSM) oxide powder with ultrafine structure has been synthesized by self-propagating combustion method. The powders were characterized by X-ray diffraction, scanning electron microscopy and laser size analysis. Compared to the powders prepared by traditional solid-phase method, the grain size of powders prepared by self-propagating combustion method is relatively small and uniform. Starting from ultrafine LSM powders, sensing electrode (SE) for NO2 mixed-potential sensors based on yttria-stablized zirconia (YSZ) was fabricated. As-obtained NO2 sensor displays fast response and high sensitivity (25.4mV/decade). The response values of the sensor have good linear relationship with the logarithm of NO2 concentration varying from 30ppm to 500ppm.Keywords:Self-propagating combustion method; La0.65Sr0.35MnO3; NOx sensor; YSZ

High-sensitivity troponin assays: analytical and clinical aspects

2016 ◽  
Vol 51 (4) ◽  
pp. 315-320
Author(s):  
Magdalena Krintus
Keyword(s):  
Myocardial Infarction ◽  
Clinical Symptoms ◽  
High Sensitivity ◽  
Reference Population ◽  
Clinical Aspects ◽  
Analytical Sensitivity ◽  
Reference Limit ◽  
Highly Sensitive ◽  
Time Required ◽  
Highly Sensitive Troponin

Cardiac troponins are considered the most sensitive and specific biomarkers for the diagnosis of acute coronary syndromes (ACS). According to the Third Universal Definition of Acute Myocardial Infarction, the diagnosis requires a rise / or fall of troponin concentration with at least one value exceeding the 99th percentile upper reference limit (URL) in a reference population with the coexistence of clinical symptoms of ischemia. The introduction of highly sensitive assays has resulted in lower detection limits for the concentration of troponin, allowing for early diagnosis of, as well as the detection of quantifiable concentrations of this biomarker in healthy subjects. According to current guidelines, the use of high-sensitivity tests can shorten the time required to make clinical decisions from the current 3-6 hours to 1-2 hours. The use of highly sensitive troponin assays also carries other potential benefits associated with their predictive value, as well as challenges that include reduced specificity for myocardial infarction, lack of standardization or the presence of biological variability. Given the increasing availability of new, highly sensitive troponin assays we should be aware that their increased analytical sensitivity and precision is accompanied by accurate clinical assessment of the patient, and takes into account other non-cardiac causes of their increased concentrations.

scholarly journals Non-specific biological markers as a screening test for diagnostic of extrapulmonary tuberculosis

2012 ◽  
Vol 64 (2) ◽  
pp. 489-495 ◽  
Author(s):  
G. Stevanovic ◽  
M. Pelemis ◽  
S. Pelemis ◽  
M. Pavlovic
Keyword(s):  
Adenosine Deaminase ◽  
Immunoglobulin G ◽  
Clinical Investigation ◽  
Extrapulmonary Tuberculosis ◽  
Unknown Origin ◽  
High Sensitivity ◽  
Serum Levels ◽  
Serum Concentrations ◽  
Extra Pulmonary Tuberculosis ◽  
Antituberculosis Therapy

Serum concentrations of adenosine deaminase were determined in 223 febrile patients. In 62, we discovered extrapulmonary tuberculosis. Serum levels of immunoglobulin G were monitored in 287 febrile patients, and 68 had extra-pulmonary tuberculosis. Serum concentrations of adenosine deaminase were significantly higher in patients with tuberculosis compared to other patients with fever of unknown origin. Serum concentrations declined during antituberculosis therapy. A correlation with the localization of infection was not found. Levels of immunoglobulin G were higher in patients with tuberculosis. Both tests had high sensitivity and specificity and could therefore be used for screening extrapulmonary tuberculosis; however, they can only be interpreted adequately following a full clinical investigation.

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