Preparation of Samples for Liquid Scintillation and Gamma Counting

2019 ◽  
pp. 151-170
Author(s):  
Howard J. Glenn
Keyword(s):  
Liquid Scintillation ◽  
Gamma Counting

Use of 125I-labeled-histamine-cyclosporin C for monitoring serum cyclosporine concentrations in transplantation patients.

1986 ◽  
Vol 32 (3) ◽  
pp. 492-495 ◽  
Author(s):  
P Y Wong ◽  
M Cheung ◽  
T K Yip ◽  
A V Mee
Keyword(s):  
Liquid Scintillation Counting ◽  
Liquid Scintillation ◽  
Scintillation Counting ◽  
Gamma Counting ◽  
Analytical Recovery ◽  
Bile Extract ◽  
Good Agreement

Abstract We synthesized an 125I-labeled-histamine-cyclosporin C tracer, to obviate the use of tritiated tracer in radioimmunoassay of cyclosporine. With this tracer, the assay results varied linearly with concentration up to at least 800 micrograms/L. The within-assay CV was 6.6% at 39 micrograms/L, 4.2% at 100 micrograms/L, and 7.0% at 300 micrograms/L (n = 15). The between-assay CV was 10.0, 6.4, and 7.8% for the same respective concentrations. Comparison with an assay involving tritiated tracer (x) showed good agreement of results: y = 3.81 + 0.927x (r = 0.975, n = 604). Analytical recovery ranged from 100 to 106%. We also compared another commercially available radioiodinated tracer ("125Iodocyclosporin"; Immunonuclear Corp.). Our tracer appeared to be more specific for cyclosporine, as determined by assaying chromatographic fractions of bile extract from a patient being treated with cyclosporine. Results with use of our tracer compared favorably with those obtained with the tritiated tracer, and our assay has the advantages of gamma counting vs liquid-scintillation counting.

Evaluation of Alternative Counting Methods for Radioimmunoassay of Hepatitis-Associated Antigen (HB Ag)

1974 ◽  
Vol 20 (7) ◽  
pp. 733-737 ◽  
Author(s):  
William C Jordan ◽  
Vina Spiehler ◽  
Robert Haendiges ◽  
Edith Zak Helman
Keyword(s):  
Acetic Acid ◽  
Liquid Scintillation ◽  
Glacial Acetic Acid ◽  
Counting Efficiency ◽  
Antigen Test ◽  
High Background ◽  
Gamma Counting ◽  
Counting Methods ◽  
Direct Counting ◽  
Iodine 125

Abstract Alternative counting methods for the Abbott "Aus-RIA" hepatitis-associated antigen test have been devised and evaluated. These methods involve solubilization of the tube-bound radiolabeled complex with glacial acetic acid, transfer of the eluate to a counting vial of choice, and measurement by either a gamma scintillation or a liquid scintillation system. These methods, when compared to the direct counting of the AusRIA tube for sera from more than 250 patients and controls, gave a correlation coefficient of 0.94 to 0.99. Iodine-125 counting efficiencies averaged 65% both for direct counting of the AusRIA tube and for gamma counting of the eluate. By liquid scintillation counting, iodine-125 counting efficiency averaged 50%. This method avoids high background, chemiluminescence, and quench, and is easy to perform. By using glacial acetic acid to solubilize the labeled material, the eluate can be counted by various types of gamma counters as well as by liquid scintillation systems.

TRITIUM RELEASE CHARACTERISTICS OF Al-Li ALLOYS EXAMINED BY LIQUID SCINTILLATION TECHNIQUE

1987 ◽  
Vol 48 (C3) ◽  
pp. C3-541-C3-545 ◽  
Author(s):  
H. SAITO ◽  
Y. ISHIDA ◽  
H. YOSHIDA
Keyword(s):  
Liquid Scintillation ◽  
Tritium Release

STEROID FORMATION IN PORCINE OVARIAN TISSUE IN VITRO

1970 ◽  
Vol 63 (3) ◽  
pp. 441-453 ◽  
Author(s):  
Asbjørn Aakvaag
Keyword(s):  
Liquid Scintillation ◽  
Specific Activity ◽  
Ovarian Tissue ◽  
Gas Liquid Chromatography ◽  
Similar Concentration ◽  
Endogenous Substrates ◽  
Exogenous Progesterone ◽  
Relative Utilization ◽  
Radioactive Substrate

ABSTRACT Slices of non-luteinized porcine ovaries have been incubated in the presence or absence of human chorionic gonadotrophin (HCG) and exogenous radioactive substrates. Progesterone, 17α-hydroxyprogesterone and androstenedione were isolated in a radiochemically pure form. The chemical mass and the specific activity were determined by gas liquid chromatography and liquid scintillation spectrometry. HCG stimulated the rate of formation of androstenedione in the absence of exogenous substrates with a factor of 4–8. In the presence of pregnenolone or progesterone at a concentration of about 2 × 10−6 mol/l the stimulatory effect of HCG was either abolished or markedly reduced. The conversion of exogenous progesterone to androstenedione was reduced in response to HCG indicating that the capacity of the tissue to convert progesterone to androstenedione was limited, and that the limit was reached at this rather low substrate concentration. These findings furthermore suggest that the endogenous rather than the exogenous radioactive substrate will be »preferred« by the tissue. The observations demonstrate the necessity of measuring both the radioactivity and the chemical mass of the products in investigations of this type using radioactive substrates. The formation of progesterone from endogenous substrates was also stimulated by HCG. [1-14C] acetate and [7α-3H]cholesterol were not utilized by the tissue for steroid formation. Exogenous [4-14C] pregnenolone and [7α-3H] progesterone in similar concentration were both utilized for production of 17α-hydroxyprogesterone and androstenedione. HCG had no effect on the relative utilization of the radioactive substrates.

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