共查询到20条相似文献,搜索用时 31 毫秒
1.
《Journal of receptor and signal transduction research》2013,33(1-4):135-145
AbstractThe TopCount(R) Microplate Scintillation Counter and the Matrix 9600(R) Direct Beta Counter are microplate compatible instruments developed to meet the needs of investigators using radioisotope assays adapted for very high throughput. This paper describes these instruments and their application to receptor binding assays. When combined with the appropriate sample handling equipment and filter media, use of these multi-detector instruments improves sample handling efficiency and shortens overall counting time. The assay protocols including filtration through glass fiber mats and membrane filters have been investigated. Results obtained from these new instruments are compared to standard techniques using conventional liquid scintillation and gamma counting. 相似文献
2.
M. T. Stephen Hsia 《Cell biology and toxicology》1987,3(2):127-142
The induction of unscheduled DNA synthesis has been considered as a suitable endpoint for the screening of genotoxic agents. Experimentally, unscheduled DNA synthesis is most frequently measured by autoradiography. The purpose of this report was to examine the usefulness of the liquid scintillation counting technique in measuring unscheduled DNA synthesis response in isolated rat hepatocytes. The various liquid scintillation counting-based unscheduled DNA synthesis assay procedures were examined according to the following groupings: (1) procedures based on the acid precipitation of cellular macromolecules, (2) procedures based on isopycnic gradient centrifugation of solubilized cells, (3) procedures based on nuclei isolation in conjunction with other DNA purification methods, and (4) procedures based on the selective retention of hepatocellular DNA. Limited cases in which test chemicals gave positive unscheduled DNA synthesis response in liquid scintillation counting-based assays and negative unscheduled DNA synthesis response in autoradiography-based assays are presented. It is concluded that liquid scintillation counting-based unscheduled DNA synthesis assays represent an appropriate system for inclusion in carcinogenicity and mutagenicity testing programs.Abbreviations 2-AAF
2-acetylaminofluorene
- 2-AF
2-aminofluorene
- AFB1
aflatoxin B1
- ARG
autoradiography
- DMN
dimethylnitrosamine
- LSC
liquid scintillation counting
- MMS
methyl methanesulfonate
- MNNG
N-methyl-N-nitro-N-nitrosoguanidine
- 4-NQO
4-nitroquinoline-1-oxide
- PCA
perchloric acid
- TCA
trichloroacetic acid
- UDS
unscheduled DNA synthesis 相似文献
3.
If emitters of energetic β-particles (such as 32P) are counted on solid supports in liquid scintillation systems, considerable distortion of the apparent energy spectrum of the β-particles can result if the material is placed on the bottoms or against the walls of vials. This results if the path length in the scintillation fluid available to a substantial proportion of the β-particles is short compared with their range. The phenomenon leads to reduced and variable efficiency in normal counting channels and to difficulties in double-labeling. 相似文献
4.
A simple, improved scintillation counting procedure was developed for the assay of radioactive mono- and polysaccharides on paper chromatograms. Segments of chromatograms are placed in scintillation vials and soaked in water to completely elute the carbohydrate before addition of Aquasol, a xylene-based scintillation fluid. The resulting water-Aquasol solution is counted in a liquid scintillation counter. Evaluation of numerous experimental variables revealed optimal conditions for complete elution of mono- and polysaccharides with water before counting in Aquasol.The water elution-Aquasol procedure allows water-soluble substances (14C- and 3H-labeled) on paper to be assayed with increased accuracy and sensitivity (three- to fivefold improvement in counting efficiency of tritiated samples). The simplicity of the procedure allows entire radiochromatograms to be assayed readily. 相似文献
5.
A simple multiwell tray for manipulation of radiolabeled nucleic acids on filter disks 总被引:1,自引:0,他引:1
R S Hayward 《Analytical biochemistry》1980,108(2):282-284
This note describes a simple tray in which large numbers of radiolabeled nucleic acid samples mounted on paper or glass-fiber disks can be subjected to various treatments prior to counting by liquid scintillation spectrometry. The tray is useful for analysis of samples from ultracentrifugal fractionation of nucleic acids, for direct sampling of RNA or DNA polymerase assays in vitro, and for analysis of nucleic acid labeling in bacterial cultures. 相似文献
6.
LuAnn Langham Barbara M. Garber Daphne A. Roe Michael N. Kazarinoff 《Analytical biochemistry》1982,125(2):329-334
A radiometric assay for pyridoxamine 5′-phosphate oxidase (pyridoxamine (pyridoxine) 5′-phosphate:O2 oxidoreductase (deaminating), EC 1.4.3.5) has been developed utilizing N-(5′-phosphopyridoxyl)[3H]tryptamine. This assay is more sensitive than previously used colorimetric and fluorescent assays for this oxidase and furthermore is applicable to erythrocytes. Tritiated substrate is incubated with an enzyme sample in the presence of excess unlabeled truptamine and the radiolabeled tryptamine product is extracted into toluene and quantitated by liquid scintillation counting. 相似文献
7.
D C Wigfield 《Analytical biochemistry》1974,59(1):11-15
A method for obtaining the true activity and counting efficiency of a 14C sample partially or completely adsorbed on the walls of a counting vial by liquid scintillation counting is presented. 相似文献
8.
Activation markers and cell proliferation as indicators of toxicity: A flow cytometric approach 总被引:1,自引:0,他引:1
Cell proliferation is an attractive endpoint inin vitro toxicity assays, since nearly any kind of damage in a cell may result in altered cell proliferation. In toxicological applications, liquid scintillation counting, measuring radioactivity from tritiated thymidine, has been the traditional way to estimate cell proliferation. An alternative approach is the measurement of BrdU incorporation by flow cytometry. Before the actual DNA synthesis starts, several proteins are expressed on the cell surface, as well as intracellularly. Among the markers on the cell surface CD69, CD25, and CD71 are sequentially expressed on human lymphocytes after a mitogenic stimulation. The aim of this study was to evaluate information obtained by analysis of expression of activation markers on cell surfaces in lymphocyte subsets and to compare it with data from cell proliferation studies performed by liquid scintillation counting and BrdU flow cytometry. The experiments were performed with phytohemagglutinin-stimulated human lymphocytes exposed to ochratoxin A and cyclosporin A. While ochratoxin A-treated cultures showed a steep inhibition with increasing concentration, the cyclosporin A treatment gave an inhibition curve with a less steep slope. Activation marker studies showed that the effect of treatment with both of the toxins was more pronounced on the late markers CD25 and CD71, while CD69 had the advantage that significant effects could be detected as early as 6 h after ochratoxin A treatment. Cyclosporin A treatment induced only minor alterations in CD69 expression. Certain differences in expression of activation markers between CD4+ and CD8+ subsets were found both in ochratoxin A- and cyclosporin A-treated cultures. A stimulating effect was found in cell cultures exposed to the lowest concentration of ochratoxin A on CD69 and CD25 expression. Signs of an increase in frequencies of proliferating cells measured with the BrdU flow cytometry method were also seen. This increase could not be detected with liquid scintillation counting. No other differences between the liquid scintillation counting and BrdU flow cytometry measurements of proliferation were obtained. We conclude that studies of activation marker expression by the flow cytometric approach used in this report are useful complements to traditional measurements of cell proliferation as they yield subsetspecific information about cellular processes which precede proliferation of lymphocytes.Abbreviations
A
pulse area
- BrdU
bromodeoxyuridine
- CD
cluster of differentiation
- FBS
fetal bovine serum
- FITC
fluorescein isothiocyanate
- FL
fluorescence
- FSC
forward light scatter
- H
pulse height
- PBS
phosphate-buffered saline
- PI
propidium iodide
- R-PE
R-phycoerythrin
- RPMI
Roswell Park Memorial Institute
- SEM
standard error of the mean
- SSC
orthogonal light scatter
- W
pulse width 相似文献
9.
Summary Two liquid scintillation fluors, the first using a 2-methoxyethanol/toluene solvent, the second a Triton X-100/toluene solvent, are discussed. Data presented indicate that the technique using the 2-methoxyethanol/toluene solvent produces higher d.p.m. than does solid support counting. The Triton X-100/toluene solvent fluor is suggested for measuring aqueous samples such as algal excretion products and 14C stock solutions. 相似文献
10.
L Hunter 《Analytical biochemistry》1978,89(1):279-283
A simple, economical method for counting acrylamide gel slices on solid filter paper supports in a toluene-based scintillation cocktail is described. Major advantages of the system include no requirement for either dissolution of the gel or elution of the radioactive material prior to emulsion counting and the direct reutilization of scintillation cocktail and vials. Additionally, 32P-labeled RNA samples can be counted with better relative efficiencies and those labeled with 14C or 33P can be determined at equivalent efficiencies. Tritium was detected less readily, with an absolute efficiency of approximately 10%. 相似文献
11.
Radiolabeling of native proteins conventionally has required iodination using 125Iodine (125I). Although radioiodination can result in high specific activity, there are several drawbacks in the use of 125I (e.g., radiological hazards and short half-life). 14C-Methylamine-glutaraldehyde conjugation to proteins offers an alternative for radiolabeling of proteins that is safer and longer-lived alpha-2-Macroglobulin was radiolabeled by conjugation to a 14C-methylamine-glutaraldehyde conjugate. Analysis of the labeling procedure was performed using scintillation counting, gel filtration chromatography, and protein assays. The radiolabeled alpha-2-macroglobulin was activated using established protocols and tested for functional integrity using competitive binding assays in the presence of recombinant receptor associated protein, an alternative ligand for the alpha-2-macroglobulin cellular receptor. The function of alpha-2-macroglobulin was unaffected by the labeling procedure. Comparison of 14C-methylamine-labeling and iodination by Scatchard analysis yielded nonlinear plots that suggested the presence of two sets of receptors with different binding affinities but that do not show cooperativity. This technique offers an alternative to radioiodination for the sensitive labeling of proteins. 相似文献
12.
V J Aloyo 《Analytical biochemistry》1979,99(1):161-164
A new one-step method for the preparation of polyacrylamide gels containing tritium and carbon-14 for liquid scintillation counting is presented. Forty-four hours after placing the gel slices in the scintillation fluid described in the text, the samples are ready for counting. This one-step method is compared to the method of D. Goodman and H. Martzura (1971, Anal. Biochem.42, 481) and is shown not only to require fewer manipulations but also to eliminate the need for a heating oven and to reduce the reagent costs. 相似文献
13.
Lasker S. Ahmed Helen Moorehead Catherine A. Leitch Edward A. Liechty 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1998,710(1-2):27-35
A method was developed for the determination of the specific activities of leucine and phenylalanine in plasma using a flow-through scintillation counter coupled with high-performance liquid chromatography components. Results were compared with those obtained from liquid scintillation counting. Differences in the specific activities of leucine and phenylalanine between the two methods were not statistically significant. We concluded that flow-through radioactivity detection can be used for quantitative amino acid assays. However, the minimum activity that can be detected may be prohibitively low in certain applications. 相似文献
14.
Quantification of 32P-labeled samples in gel fragments using the flat-bed liquid scintillation counter 总被引:2,自引:0,他引:2
Quantification of 32P in bands after gel electrophoresis was performed using the flat-bed scintillation counter (Betaplate). The most convenient system involved placing fragments of dried gel between two glass fiber sheets, each previously sealed in a thin plastic bag with liquid scintillant. Good pulse-height spectra and counting efficiencies were obtained with low cross talk and background. The method has been used to quantify mRNA in RNA antisense-protection assays that were linear over a wide range (1-20000 cpm). Cross talk and background could be reduced further by an alternative technique utilizing plastic trays with shallow wells in which a solid scintillant had been melted. Fragments were immersed in the molten scintillant (90 degrees C), which was allowed to solidify, by cooling, before counting. 相似文献
15.
Improvements in and Environmental Applications of Double-Vial Radiorespirometry for the Study of Microbial Mineralization 总被引:4,自引:3,他引:1
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Several variations in the scintillation mixture and the filter paper arrangements for double-vial radiorespirometry were compared. Improved efficiencies (44%) and shorter response times were found by adding wetting agents and methanolic NaOH to the scintillation mixture in the filter paper. The scintillation chemicals used did not contain dioxane and were found to be nontoxic to the test microbiota in this system. Covering the inner reaction vial with aluminum foil minimized the reduction in counting efficiency when testing colored or dense environmental samples. Mineralization rates were determined with 14C-labeled glucose, acetate, and glutamate and [14C]cellulose- and [14C]lignin-labeled lignocellulose for composting cow manure, forest soil, and arctic lake sediment microbiota. This improved method can be used in a variety of procedures involving the measurement of microbial mineralizations of organic compounds. Since no liquid scintillation cocktail is used for counting, the radioactive wastes are aqueous or can be incinerated, making disposal easy. 相似文献
16.
The counting rate of [1-14C]trichloroacetic acid (TCA) was not stable in a standard toluene/Triton X-100 liquid scintillation solution because this compound becomes partially degraded to 14CO2 and CHCl3. Both toluene and Triton were contributing factors in causing this degradation. The NCS solubilizer added to the toluene/Triton scintillation solution trapped 14CO2 and stabilized counting rates of [1-14C]TCA. When [2-14C]TCA was used, 14CHCl3 remained in the scintillation solution resulting in stable counting rates without the addition of NCS. 相似文献
17.
Isabelle Ayni Christine Vauthier Monique Foulquier Claude Malvy Elias Fattal Patrick Couvreur 《Analytical biochemistry》1996,240(2):202
A quantitative polyacrylamide gel electrophoresis (PAGE) analysis using a multichannel radioactivity counter was designed for the evaluation of33P-labeled antisense oligonucleotide associated with polymeric drug carrier (nanoparticles). The proposed analytical method was first validated. The criteria of specificity, linearity, reliability, detection and quantification limits, and resolution power were determined. Results were compared to those obtained using liquid scintillation counting of crude samples or after solubilization of gel slices. The proposed method gave a better linearity and reliability than liquid scintillation counting of solubilized gel slices. In comparison with the liquid scintillation counting of crude samples, the method presented the advantage of being able to directly separate oligonucleotides differing by only one nucleotide in length. This method was applied for the separation of free oligonucleotides and oligonucleotides bound onto nanoparticles, allowing quantification of the amount of free and bound oligonucleotides without any further separation steps. Thus, because it is easy and rapid, the quantitative PAGE analysis using a multichannel radioactivity counter offers interesting possibilities for the characterization of oligonucleotide nanoparticles. 相似文献
18.
The data presented demonstrate the potential of surfactant-fortified scintillation cocktails in overcoming many of the problems encountered in the quantitation of radioactivity on solid supports. Using a broad range of representative ionic and polar biochemical compounds, the in vial elution and quantitative recovery of 3H and 14C-labeled components from a wide assortment of common solid support media has been demonstrated. This methodology in combination with zero elution counting systems and in some circumstances gelled suspension counting should combine to overcome most of the problems associated with determination of isotopic activity on such solid support media. 相似文献
19.
Summary A method has been devised to count emissions from K42 in plant tissue by liquid scintillation spectrometer with low quenching. The plant samples were ashed in aluminium dishes, folded into aluminium wafers and suspended in the liquid scintillator of counting vials. The samples were counted in a scintillation spectrometer at one to five minute intervals seven or more times and until the total exceeded 1000 counts. The efficiency of counting was approximately 70%.A computer program was written to calculate decay corrections for the short half-life isotope K42. The program computed the weighted mean of the counts, standard deviation of the mean, percentage standard deviation of the mean and Chi-square value for each sample. The measurements were precise enough for K-uptake studies. 相似文献
20.
The present paper describes a new spectrophotometric assay for HGPRTase activity which is more rapid than and as sensitive as the isotopic assays for this enzyme and which avoids the use of high-voltage electrophoresis and liquid scintillation counting. 相似文献