Radioimmunoassays defined

Standard curves performed under our defined radioimmunoassay conditions ([ H]PbTx-3 = 1 nM, antiserum dilution = 1 2000, assay volume = 1 ml) demonstrated the ability of this antiserum to bind equally to PbTx-2 and PbTx-3, suggesting specificity for the cyclic polyether backbone region of the molecule (Figure 8). The linear portion of the curve indicated a lower detection limit of 0.2-0.5 ng in saline buffer under these conditions. Evaluation of this assay for use with biological fluids and tissue extracts is underway. 

The comparison of clinically defined and documented toxic with non-toxic consumed fishes by EIA clearly demonstrated a statistically significant difference (p <0.001) between the two populations. This result is similar to that reported for the radioimmunoassay and enzyme-immunoassay procedures (21, 22, 26-28). The assessment of the EIA with each species of fish samples caught in the Hawaiian waters presented positive and borderline frequency values comparable to that reported earlier by Ito and Uchida (28) by the RIA, and more recently by Kimura et al. (27) by the EIA. 

Terms in bold are defined i neuroendocrine system 882 radioimmunoassay (RIA) 884 Scatchard analysis 884 endocrine glands 886 paracrine 886 autocrine 886 insulin 887 epinephrine 888 norepinephrine 888 catecholamines 888 eicosanoid... 

Individual animals immunized with the same substance can produce antibodies that may differ in affinities, titer, and specificities. " Such differences are appeu-ent with antibodies studied by the more classical physical chemical procedures. However, even among anti-enzyme sera harvested from individual rabbits that had been immunized with -lactamase, some were found to neutralize the activity of the enzyme, others to stimulate its activity, and still others were stimulatory and then inhibitory at higher concentrations." In radioimmunoassay, each antiserum from an individual animal must be characterized separately to select those that have the proper affinities and specificities. The production of monoclonal antibodies by hybridoma technology can yield molecules with defined specificities and affinities. As this technology becomes affordable for the average research laboratory, problems associated with antibody heterogeneity are due to diminish. 

The efficiency of a separation procedure in radioimmunoassay can be defined as the completeness with which the free and bound fractions are separated. This concept is illustrated diagrammatically in Fig. . ... 

Adequate binding affinity for tumor localization has not been defined, although the importance of high affinity for maximal cell binding and for sensitive in vitro radioimmunoassay has been shown (41-43). It has, however, also been suggested that low affinity is preferable in vivo to allow more tissue penetration and avoid trapping of tightly bound antibody at the tumor surface... 

The amount of these recoverable materials from the microorganisms is very small, when compared to the production of enzymes or secondary metabolites such as antibiotics. Thus, to convincingly demonstrate the presence of hormonal peptides in microorganisms the fermentation of large quantities of cells in defined medium was required as well as improved large scale extraction and purification procedures. In addition, we utilized very sensitive and specific radioimmunoassays and bioassays for detecting the low concentration of these materials. 

In summary, the capillary perfusion system represents a simple in vitrc technique for the quantitation of protein adsorption and platelet accumulation on artificial surfaces under well defined hydrodynamic conditions (0-4.,000 s ). Radioisotopic methods enable simultaneous study of platelet deposition and adsorption of one or more plasma proteins. Experiments may be performed using washed platelet suspensions or anticoagulated whole blood, platelet deposition being measured in the latter case by surface phase radioimmunoassay with a... 

The various chemicals to which HCWs can potentially be exposed and which have been reported to cause CU are listed in Table 5. Practitioners evaluating HCWs for CU should be cautious in testing these chemicals, since appropriate test concentrations have not been defined and anaphylactic reactions are a serious threat, even with prick testing. Furthermore, except for latex, serologic testing is not available. In the case of latex, a radioimmunoassay (RIA) can be... 

Vitamin A (retinol) mobilization from the liver is highly regulated by factors that control the rates of RBP synthesis and secretion by the liver. Considerable information is now available about the molecular and cellular events involved in the synthesis and secretion of RBP by the liver cell and about the mechanisms that regulate these events. The studies directed toward defining these phenomena have employed the rat as an animal model and a sensitive and specific radioimmunoassay for rat RBP (Muto et al., 1972). Studies have been conducted both with intact animals and with isolated liver cells in culture. 

In this kind of work, monospecificity was operationally defined by the experimental demonstration that only one molecule of the antibody population can bind to one molecule of the antigen. Under these conditions, the complex formed is soluble and a radioimmunoassay or a double precipitation must be performed to quantitate the determination. 

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