Marker radioactive

Currently, there are several assays for the measurement of PSA. All of them contain monoclonal or polyclonal antibodies labeled with enzymatic, fluorometric, or radioactive markers. These assays have shown significant variations within the same patient specimens. These variations may result from differences in antibody specificity, reaction kinetics, calibration, or the system s sensitivity. Studies have shown that only free PSA and PSA-ACT show immunological reactivity in these assays. Also, reaction kinetics can influence the molar ratio. Some of these assays with shorter incubation times may specifically bind the free PSA molecule (which is a lower weight form of PSA). In the equimolar assays, changing the incubation... 

Of particular interest to this review is the use of luminescent lanthanide (especially europium and terbium) materials as non-radioactive markers (3,5,8,10 12,16). In addition to the safety advantages over radioactive labels, lanthanide complexes remain luminescent as long as the complex remains intact, allowing repeated detection of analytes over a much longer time period than radioactive labels. 

Access to nucleic acid dendrimers is initiated by a zip-fastener like dissociation of the DNA double strand by heating. The double strand separates into the two individual strands by thermal motion (denaturation). Subsequent association, hybridisation of complementary sequences, is followed by stepwise cross-linking to form DNA dendrimers, which can contain up to two million oligonucleotide-end group strands (Fig. 8.19). The latter can be labelled with fluorescence or radioactive markers. 

Sensitivity of immunoassays is largely conditioned by markers applied for conjugation with the antibody. Traditional immunodetection methods ELISA with radioactive markers (radioimmunoassay—RIA), enzymatic markers (enzyme immunoassays—El A), or fluorescent markers (fluoroenzyme immunoassays FEIA) are currently the most widely used techniques in laboratory analysis of allergens as well as in clinical studies for determination of general and specific IgE and other subclasses of immunoglobulines, e.g., IgG4 in the Immuno-CAP system (Samson, 2001 Duran-Tauleria et al., 2004 Lidholm et al., 2006). 

TAE (IX TAE is 40 mM Tris-acetate, 2 mM EDTA), with the gel containing 10 fig/ml ethidium bromide to stain the DNA. Addition of approximately 5000 cpm of a 2P-end-labeled Hindlll digest of X DNA to an unlabeled digest will provide radioactive markers that correspond to the visible markers. 

Other radioactive markers useful for archeology are tritium ... 

The location of a single unit in the GI tract is determined from the position of the gamma camera image. Since no image of the GI anatomy is obtainable, an external radioactive marker may be positioned at a well-defined anatomical position as a reference point in the determination of the radiolabelled formulation. Another approach for facilitating determination of... 

Naumann and Reinhardt [329] described the use of the radioactive marker method to determine the oxide solubilities. The advantages of this method concern only the procedure for the subsequent treatment of the obtained sample of the melt with the metal oxide, whereas its drawbacks are similar to those of the classic isothermal saturation methods. This radiochemical method has not been used extensively for solubility determinations in molten salts. 

An isolated nucleic acid can then be quantified, for example by UV spectroscopy. The aromatic groups of the bases have an absorption maximum around k = 260 nm. Alternatively, fiuorescent or radioactive markers can be attached and quantitatively detected. A mixture of DNA molecules can be quantified by capillary electrophoretic methods (section 3.3). 

There are four commonly favored isotopes for the labehng of antigen or antibody in RIA. These are and which vary greatly in their half-Hves and their specific activities. A critical factor in the choice of a radioactive marker is the specific activity of the isotope. The importance of half-life in radioactive emission is evident when the relative specific activities of the different isotopes are calculated. A radioactive marker of low specific activity requires a relatively high concentration of this marker in... 

The minerals are held in different forms in the body, which can be considered as compartments. There is a central reserve or interchange compartment, which is usually blood plasma, and one or more compartments that interchange the mineral with the central compartment at various rates, e.g. compartments easy or difficult to mobilise. Metabolic processes take place via the central reserve (plasma), which receives minerals from other compartments, the digestive tract and the difficult to mobilise compartment. The central reserve secretes mineral into the readily mobilised compartments, the difficult to mobilise compartment, the gastrointestinal tract, the kidneys and milk. The flux between the compartments can be measured by a combination of balance trials and injection of radioactive marker followed by sampling the tissues over time. An example of the body compartments of copper is shown in Fig. 6.1. 

They argued that if the extracted a-amylase contained (and was consequently heavier) it must have been synthesized from the amino acids. This would be proof of de novo synthesis of the enzyme which could be separated from light ( O) enzyme on the basis of its density. In order to obtain a convenient label for the light enzyme, Filner and Varner first incubated aleurone layers in GA3, plus H-lysine. The H-labelled a-amylase-produced was collected and placed on an equilibrium density gradient (cesium chloride). An initial experiment showed a coincidence between the radioactive ( H) peak and that of assayable a-amylase activity (Fig. 7.2A). The fact that a-amylase could incorporate H-lysine was, of course, good evidence for its de novo synthesis, but the final proof came when it was shown that assayed a-amylase synthesized in GA3-treated aleurone layers incubated in H2 0 was heavier than the radioactive marker ( H) peak (Fig. 7.2B). 

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