Effects of contaminant radioactivity on results of 125I-radioligand assay.

1979 ◽  
Vol 25 (11) ◽  
pp. 1975-1977 ◽  
Author(s):  
L R Witherspoon ◽  
S E Shuler ◽  
M M Garcia ◽  
L A Zollinger

Abstract Diagnostic radionuclide imaging procedures are often used in patients whose sera are later assayed by use of 125I-labeled radioligands; thus, it is important to identify those assays that potentially may be affected by contaminating radioactivity. Results obtained with assays in which specific separation methods (solid-phase primary antibody, second antibody) or small (10--25 micdo L) sample volumes are used are little affected by the presence of such contaminating radioactivity. Less-specific techniques (polyethylene glycol, charcoal, ion-exchange resin) segregate some of the contaminant activity into the bound fraction. The degree to which such activity is protein bound and the concentration of endogenous ligand then contribute to the resulting error in dose estimation. Samples for these assays should be screened for radioactivity before the assay is begun. Inclusion of nonspecific binding tubes for patients' samples when contamination is present permits the contaminating radioactivity to be evaluated and the patient's dose concentration to be more accurately estimated.

1983 ◽  
Vol 15 (8-9) ◽  
pp. 309-319 ◽  
Author(s):  
M S Salkinoja-Salonen ◽  
R Hakulinen ◽  
R Valo ◽  
J Apajalahti

Biodegradation in fixed film reactors of chloroorganic compounds in kraft bleaching effluent and in pesticides was studied. Specific biofilm reactors could be adapted for the mineralization of chloroform, chlorophenols, chlorocatechols, chloroguaiacols, chloroveratroles and chlorinated resin acids in bleaching effluent and for chlorophenols in spills of pesticides for blue stain and wood rot. Mineralization of chloroorganic compounds into inorganic chloride and carbon dioxide occurred in the solid phase of the reactor. The ability to degrade the chlorine compounds could be transferred from one reactor to another by transferring the liquid but no degradation occurred before addition of solids in the reactor. The degradation of pentachlorophenol was most active when softwood bark was used as the solid material It was less active on unglazed pottery, and inactive on glass (beads or fibre), cellulosic fibre, clay and ion exchange resin. The mineralization of the chloroorganics occuring in kraft bleaching effluent was less fastidious about the type of solid materials used. The biofilm grew equally well on softwood bark, ion exchange resin and various types of plastic and fiber.


2016 ◽  
Vol 52 ◽  
pp. 171-176
Author(s):  
M. Palkina ◽  
O. Metlitska

The aim of the research – adaptation, optimization and using of existing DNA extraction methods from bees’ biological material with the reagent «Chelex-100" under complex economic conditions of native laboratories, which will optimize labour costs and improve the economic performance of DNA extraction protocol. Materials and methods. In order to conduct the research the samples of honey bees’ biological material: queen pupae exuviae, larvae of drone brood, some adult bees’ bodies (head and thorax) were selected. Bowl and drone brood were obtained from the experimental bee hives of Institute of Apiculture nd. a. P. I. Prokopovich of NAAS. DNA extraction from biosamples of Apis mellifera ssp. was carried out using «Chelex-100®» ion exchange resin in different concentrations and combinations. Before setting tests for determination of quantitative and quality indexes, dilution of DNA samples of the probed object was conducted in ratio 1:40. The degree of contamination with protein and polysaccharide fractions (OD 260/230), quantitative content of DNA (OD 260/280) in the extracted tests were conducted using spectrophotometer of «Biospec – nano» at the terms of sample volume in 2 µl and length of optical way in 0,7 mm [7]. Verification of DNA samples from biological material of bees, isolated by «Chelex-100®», was conducted after cold keeping during 24 hours at 20°C using PСR with primaries to the fragment of gene of quantitative trait locus (QTL) Sting-2 of next structure [8]:  3' – CTC GAC GAG ACG ACC AAC TTG – 5’; 3' – AAC CAG AGT ATC GCG AGT GTT AC – 5’ Program of amplification: 94 °C – 5 minutes – 1 cycle; 94 °C – 1 minute, 57°C – 1 minute, 72 °C – 2 minutes – 30 cycles; elongation after 72°C during 2 minutes – 1 cycle. The division of obtained amplicons was conducted by gel electrophoresis at a low current – 7 µÀ, in 1,5 % agarose gel (Sigma ®) in TAE buffer [7]. The results. At the time of optimization of DNA isolation methods, according to existing methods of foreign experts, it was found optimal volume of ion exchange resin solution was in the proposed concentration: instead of 60 µl of solution used 120 µl of «Chelex-100®», time of incubation was also amended from 30 minutes to 180 minutes [9]. The use of the author's combination of method «Chelex-100®» with lysis enzymes, proteinase K and detergents (1M dithiothreitol), as time of incubation was also amended, which was reduced to 180 minutes instead of the proposed 12 hours [10]. Changes in quality characteristics of obtained DNA in samples after reduction in incubation time were not found. Conclusions. The most economical method of DNA isolation from bees’ biological material is 20% solution of «Chelex-100» ion exchange resin with the duration of the incubation period of 180 minutes. It should also be noted that the best results can be obtained from exuviae, selected immediately after the queen’s exit from bowl, that reduces the likelihood of DNA molecules destruction under the influence of nucleases activation, but not later than 12 hours from release using the technology of isolated obtain of queens.


1977 ◽  
Vol 49 (6) ◽  
pp. 764-766 ◽  
Author(s):  
Toshihiko. Hanai ◽  
Harold F. Walton

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