Samples For Liquid Scintillation Counting Research Articles

Steroid receptors in breast cancer: Sources of inter-laboratory variation in dextran-charcoal assays

The presently recognized correlations between various clinical parameters and the concentrations of estrogen and progesterone receptors in breast cancer biopsies are largely based on receptor values obtained using the dextran-coated charcoal (DCC) method. This assay method is highly sensitive to slight changes in assay protocol, and differences in assay methodology may account for the wide variation in proportions of receptor positive patients reported by different centers. A survey of various aspects of the assay method that may lead to reproducible, systematic differences in concentrations of receptor levels is presented; and methods of compensating for or correcting these potential differences are discussed. The following aspects are considered: a) constitution of biopsy tissue, b) method of tissue homogenization, c) absorption of ligands to surfaces, d) inclusion of molybdate in the assay buffer, e) composition of the DCC slurry, and f) handling of samples for liquid scintillation counting. Differences in methods used to homogenize tissue in Europe and the U.S.A. may account for differences observed in the correlation of DCC assay results obtained using the recently-introduced monoclonal ER-EIA technique.

Preparation of 14C-labeled algal samples for liquid scintillation counting

Four commonly used techniques for preparation of 14C-labeled algal samples on membranes for liquid scintillation counting were compared and a simple technique for apparent net assimilation measurement from aqueous samples was introduced. All four techniques yielded similar radioactivities from the test cultures and are thus suitable for measurements of 14C algal samples. The possibly carcinogenic solvent dioxane was not necessary with PCS scintillation cocktail for dissolving radioactivity from algae on filters.

A rapid, hygienic method for the preparation of fecal samples for liquid scintillation counting

A method for the preparation of fecal samples for liquid scintillation counting is described which is rapid, hygienic, and inexpensive. By the use of a novel type of homogenizer, fecal samples can be homogenized while totally enclosed within a sealed, plastic bag, so reducing the possible risk of infection. The subsequent preparation of a clear solution suitable for liquid seintillation counting is performed using an “in-vial” digestion technique which enables any 14CO 2 released during digestion to be trapped within the vial.

XCI. Combustion instruments for preparing samples for liquid scintillation counting (correction)

XCI. Combustion instruments for preparing samples for liquid scintillation counting (correction)

XCI. Combustion instruments for preparing samples for liquid scintillation counting

Examines a typical oxygen flask combustion apparatus, the Peterson combustion apparatus, the Oxymat, the Packard-Kaartinen instrument, the Harvey oxidizer, and the Noakes-Searle spark combustion apparatus.

An efficient inexpensive multisleeve liquid scintillation counting system

This paper reports a method that conserves greatly on the cost of counting radioactive samples for liquid scintillation counting. It accomplishes this by using several glass sleeves that are much more inexpensive than conventional counting and/or minivials, and because volumes of counting fluid are reduced the cost of the counting fluid is also markedly reduced. The usual vial system (A) uses 15 ml of counting fluid with 37% efficiency for tritum; the minivial uses .75 ml with 37% efficiency while 0.15 and 30 μl volumes gave approximately 21% efficiency. Another feature of this system is the capacity to reuse the outer sleeve(s) and dispose of the smaller counting vessel. This means that less counting fluid and glass will have to be disposed of in the environment.

Sample Oxidizerの使用経験

The Sample Oxidizer automatically prepares samples for liquid scintillation counting containing singlelabel tritium (^3H), single-label carbon-14 (^<14>C) or both nuclides in double-label. Double-label samples of tritium and carbon-14 are chemically separated during preparation. Recovery of tritium was about 90% with 0.2 gram of most materials. Recovery of carbon-14 was about 85%. Memory effect for tritium and carbon-14 was less than 0.6% with most samples. But Sample Oxidizer was not suitable for fatty samples. We adopt the "Sample Oxidizer Method" as to tissues, the "Hyamine 10X Method" as to fatty samples and the "Direct Method" as to serum.

A new combustion system for rapid preparation of biological samples for liquid scintillation counting

A combustion tube equipped with two oxygen supply nozzles was developed for preparation of biological samples for liquid scintillation analysis. By using this new combustion system, relatively large quantities of biological tissues were easily burned within a few minutes and [ 14C]O 2 and/or [ 3H] 2O thus produced were promptly and quantitatively recovered. This system proved to have several advantageous characteristics, i.e., simple construction, easy and safe operation and no need of a catalyst such as cupric oxide for complete combustion.

A comparison of methods for the preparation of 14C-labelled plant tissues for liquid scintillation counting

Four methods for the preparation of 14C-labelled plant tissues for liquid scintillation counting have been compared for accuracy and precision. The wet oxidation method of Mahin and Lofberg, although easy and rapid, proved to be unsuitable for obtaining a reliable estimate of 14C present in lyophilized plant material, showing non-quantitative recovery and poor reproducibility. Solubilization in Hyamine hydroxide provided accurate and reproducible results, if experimental conditions were strictly adhered to; however, especially when larger samples were employed, severe—and variable—color quenching resulted in very low counting efficiency, which necessitated construction of quench correction curves specific for each source of plant material. Van Slyke wet combustion, in a device slightly modified after Jeffay and Alvarez, on the other hand, always resulted in reproducible and reliable data, irrespective of the carbon compound administered and the nature of the plant material. With samples of up to about 10 mg, Schöniger dry combustion in the Micro-Mat BF 5010 oxidation system even outrivalled Van Slyke wet combustion, because of speed and ease of manipulation. The latter methods are, therefore, evidently superior to the wet oxidation method of Mahin and Lofberg and solubilization in Hyamine hydroxide in preparing plant tissue samples for liquid scintillation counting.

Preparation of gas samples for liquid scintillation counting of carbon-14

Preparation of gas samples for liquid scintillation counting of carbon-14

Preparation of tissues for liquid scintillation radioactivity counting

A method of preparation of biological samples for liquid scintillation counting is presented. The method produces samples with a low degree of quenching and is especially suitable when radionuclides of very low energy of emission are used. Small amounts of Triton X-100 and NCS (Nuclear Chicago Corp.) are used to dissolve completely 20 mg of tissue in a scintillation mixture, followed by optionl bleaching of the solution by exposure to light.

A carbon dioxide collection accessory for the rapid combustion apparatus for preparation of biological samples for liquid scintillation analysis

A carbon dioxide collection accessory is described for the previously reported combustion system for preparation of biological samples for liquid scintillation counting. A sample can be burned and collected every 3 min. Sample size is limited by the capacity of the solvent to absorb carbon dioxide without precipitation. The system can be used for collecting water as well as carbon dioxide, for double isotope counting. The method has a collection recovery of 97%, is calibrated by internal standards, and shows a coefficient of variation of 1.1%.

Preparation of aqueous samples for liquid scintillation counting with the aid of freeze‐drying

Preparation of aqueous samples for liquid scintillation counting with the aid of freeze‐drying

The use of benzene phosphinic acid to prepare mixed samples of 55Fe and 59Fe for liquid scintillation counting.

Abstract Currently available methods for detecting the emissions of 55 Fe involve electroplating of the iron or preparation of samples for liquid scintillation counting. The latter technique is readily available to most laboratories; however, current methodology is complex, may be hazardous, and the samples are, not indefinitely stable. The use of benzene phosphinic acid to precipitate iron as an insoluble white compound, ferric benzene phosphinate, avoids these problems. The method described is highly reproducible and results in suitable efficiency for counting mixed samples containing 55 Fe and 59 Fe with standard liquid scintillation techniques.

Simple Method for Determination of 14CO2 from Expired Air

Two simple procedures for preparation of homogeneous 14CO2 samples for liquid scintillation counting are described. In one procedure (A), the carbon dioxide absorbing agent and the carbonate solution are placed in one tube. Carbon dioxide is released from the carbonate solution by sulfuric acid and absorbed by phenethyl-amine directly. Added NaH14CO3 (16–8000 dpm/ml.) is recovered nearly quantitatively in the amine phase. Similar results are obtained with another procedure (B), with which 14CO2 is released from the carbonate solution and flushed with nitrogen into a counting vial containing absolute methanol and phenethylamine.

Simplification of oxygen-flask combustion procedure for preparation of samples for liquid scintillation counting

Simplification of oxygen-flask combustion procedure for preparation of samples for liquid scintillation counting