Radioimmunoassay

Radioimmunoassay is a scientific method used to test antigens without the need to use a bioassay. It involves mixing known quantities of radioactive antigen with antibody to that antigen, then adding unlabeled or "cold" antigen and measuring the amount of labeled antigen displaced.Initially, the radioactive antigen is bound to the antibodies. When "cold" antigen is added, the two compete for antibody binding sites - at higher concentrations of "cold" antigen, more of it binds to the antibody, displacing the radioactive variant. The bound antigens are separated from the unbound ones.One method of separation used initially was the use of a second antibody directed against the first for precipitation and centrifugation. The use of charcoal suspension for precipitation was extended but replaced later by Drs. Werner and Acebedo at Columbia University for RIA of T3 and T4. An ultramicro RIA for human TSH was published in BBRC by Drs. Acebedo, Hayek et al. The free hormone stays in the supernatant, the radioactivity of which is measured and a binding curve is plotted. The technique is both extremely sensitive and specific, but it requires special precautions , sophisticated apparatus, and is expensive. The technique has been largely replaced by the ELISA method where instead of a radioactive signal, the antigen-antibody reaction is measured by colorometric signals. The RIA was developed by Rosalyn Yalow and Solomon Aaron Berson in the 1950s. Rosalyn Sussman Yalow received the 1977 Nobel Prize in Medicine for the development of the RIA for insulin. The precise measurement of minute amounts of such a hormone was a key event in endocrinology. (From the Wikpedia article Radioimmunoassay.)

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Recent Publications on Radioimmunoassay:
GAD65 IgG autoantibodies in stiff person syndrome: clonality, avidity and persistence. Background and purpose: Persistent intrathecal production of IgG...	19th July, 2008	Department of Neurology, Ulleval University Hospital, Oslo, Norway.	Eur J Neurol. 2008 Jul 9;. DOI Direct Link
5alpha-dihydrotestosterone up-regulates transthyretin levels in mice and rat choroid plexus via an androgen receptor independent pathway. Transthyretin (TTR) is a 55 kDa plasma homotetrameric protein mainly...	19th July, 2008	Health Sciences Research Centre - CICS, University of Beira Interior, Av.	Brain Res. 2008 Jul 2;. DOI Direct Link
Refinement of a commercial bench-top relaxin assay for pregnancy diagnosis using urine from domestic and nondomestic felids. Relaxin, a 6-kDa polypeptide hormone, is excreted in the urine during...	19th July, 2008	Center for Conservation and Research of Endangered Wildlife, Cincinnati	J Zoo Wildl Med. 2008 Jun;39(2):170-9.
Hypotonicity and Peptide Discharge from a Single Vesicle. Neuroendocrine secretory vesicles discharge their cargo in response to a...	18th July, 2008	NICHD, NIH.	Am J Physiol Cell Physiol. 2008 Jul 16;. DOI Direct Link
Temporal and spatial expression of IGF-I and IGFBP-1 during acute-phase response induced by localized inflammation in rats. OBJECTIVE: The acute-phase response (APR), a cytokine-induced defense...	18th July, 2008	Department of Medicine, Division of Gastroenterology and Endocrinology,	Growth Horm IGF Res. 2008 Jul 14;. DOI Direct Link
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BioNews Results for Radioimmunoassay:
Key Challenges and Issues facing the World Immunoassay Instruments Market	Macro World Investor:  Jul 2 2008 5:50PM Matching: radioimmunoassay
Key Challenges and Issues facing the World Immunoassay Instruments Market	Calibre Macro World:  Jul 2 2008 5:17PM Matching: radioimmunoassay

Radioimmunoassay Clinical Trials:
Effect of a Low-Calorie Diet and/or Exercise Program on Risk Factors for Developing Breast Cancer in Overweight or Obese Postmenopausal Women	Breast Cancer;   Obesity;   Weight Changes

Radioimmunoassay Patents:
US Patent No.	Title
7393917	PRO1482 polypeptides
7396663	Isolated polynucleotide encoding a G-protein coupled receptor
7396691	Method for the detection of fluoride or hydrogen fluoride and detection kit
7396809	Methods and reagents for treating glucose metabolic disorders
7396810	Compositions and methods for treating cancer by modulating HER-2 and EGF receptors
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Companies working in the area of Radioimmunoassay from Bioportfolio's Biocorporate database :
Company Name
Cisbio-US, Inc Cisbio International is a privately held innovative company committed to improving human healthcare with more than 50 years of experience in the fileds of therapy, medical diagnostic and drug... www.htrf-assays.com/        View full profile
MEDICORP LTD MEDICORP is Canada's largest, independent ISO 9001-certified manufacturer and distributor of immunodiagnostic and microbiology products. Included are enzyme immunoassay [ELISA], immunoradiometric ... www.medicorp.com/        View full profile

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