Radioimmuno assay

RIA Radioimmuno assay uses a radioactive label on the antibody or antigen. These were among some of the first types of immunoassays. 

Antibody Assays Monoclonal antibodies can be analyzed by the solid-phase assay techniques such as enzyme linked immunosorbent assays (ELISA) or radioimmuno assays (RIA). The typical assay procedures are as follows (Figure 5.9)... 

The Step 3 product was ground and sieved with a mortar and pestle and passed through a 125 p sieve. Rats were administered 6.75 mg of the experimental agent by injection in a medium consisting of 2% carboxymethylcellulose, 1% Tween 20 , and saline. Blood samples were collected at various time intervals, and the plasma levels of Lanreotide was determined by radioimmuno assay. Test results for are provided in Table 1. 

TABLE 1. In vivo test results for Lanreotide in plasma levels using radioimmuno assay. 

Figure 2-13. Principle of radioimmuno assay (RIA) and enzyme-linked immunoabsorbent assay (ELISA). RIA and ELISA both depend on the highly specific interaction of an antibody with an antigen to determine, for example, the amount of antigen immobilised on a surface. In the example illustrated above, that is achieved by first binding a specific antibody to the surface-bound antigen, and then adding a second antibody which binds specifically to the first. For RIA, the second antibody is radioactively...

Chan-Palay et al. (1981) found eoexistence of GAD and motilin in 10-20% of the Purkinje cells of the rat. The presenee of motilin in Purkinje cells has, however, been disputed by Lange (1986), who was unable to demonstrate the presence of motilin using radioimmuno-assay and reversed phase HPLC in extracts of rat cerebellum. Only one of Lange s anti-motilin antibodies, all of which had been demonstrated to be effective in demonstrating motilin-like immunoreactivity in rat duodenum, was found to im-munoreaet with Purkinje cells in immunocytochemical studies with rat cerebellum. 

F9. Freychet, P., Study of immunological cross-reactions and specificity of human thyrotropin (HTSH) by means of radioimmuno-assay. Abstracts of brief communications. Proc. 3rd Intern. Congr. Endocrinol., Mexico City, 1968 Intern. Congr. Ser. No. 157, p. 13 Excerpta Med. Found., Amsterdam, 1968. 

Note-. (1-9) Organic acid disorders, (10-14) fatty acid oxidation disorders, (15-20) amino acid disorders, (21-23) hemoglobinopathies, (24 and 25) endocrinopathy, (26) other inborn error of metabolism, (27) carbohydrate disorders, (28) miscellaneous genetic conditions, and (29) infectious diseases. MS/MS tandem mass spectrometry, HPLC high pressure hquid chromatography, lEF isoelectrofocusing, RIA radioimmuno assay, and ELISA enzyme-linked immunosorbent assay. 

Substitution. Obviously, if it is possible to perform the experiment without the use of radioactive substances, then all exposure is avoided. For example, the ELISA (Enzyme-linked immunosorbant assay) technique has replaced that of RIA (Radioimmuno assay) for many procedures. 

---