PSA

產品名稱：PSA IRMA
產    地：Demeditec 
產品貨號：DE36100
產品規格：100 Tests
產品說明：
Special remarks:
1.Description
The 125I?PSA IRMA system provides direct quantitative in vitro determination of human Prostate Specific Antigen (PSA) in human serum. PSA can be assayed in the range of 0?50 ng/ml using 100 µl serum samples.
2.Introduction
Prostate Specific Antigen (PSA) is a tissue-specific serine protease similar to the chymotrypsin- like glandular kallikreins. The active enzyme is a single chain glycoprotein of 237 amino acids (approximately 30 kDa). PSA is mainly responsible for gel dissolution in freshly ejaculated semen by proteolysis of the major gel forming proteins. The major part (70-90 %) of PSA in serum is complexed to alfa1-antichymotrypsin (ACT). Total PSA (free+ACT-complex) is increased in both benign prostate hyperplasia and malignant prostate cancer.
Reliable determination of PSA has long been the subject to scientific criticism, due to special analytical difficulties encountered. Immunoassays may detect two forms of PSA in different molar ratio, a fact that may result in significiant differences of values assigned. Ideally, a reliable total PSA immunoassay is characterized by an equimolar response to both free and complex forms of PSA, contrary to those showing different immunoreactivity towards these forms ("skewed response assays"). The lack of international reference material makes it even more difficult to assign true values to PSA in serum.
The current IRMA system is characterized with an equimolar response to these two forms of PSA, and has been functionally calibrated against FDA-approved immunoassays according to recommendations of international standardization committees.
Another prominent feature of total PSA immunoassays is the sensitivity which determines their suitability for monitoring cancer therapy, particularly surgical prostatectomy, associated with a virtually zero-level of PSA. The outstanding sensitivity, <0.01 ng/ml, of present IRMA system makes it particularly suitable for assaying ultra-low concentrations of PSA.
3.Principle of method
The technology uses two high affinity monoclonal antibodies in an immunoradiometric assay (IRMA) system.
The 125I labelled signal-antibody binds to an epitope of the PSA molecule spatially different from that recognized by the biotin-capture-antibody. The two antibodies react simultaneously with the antigen present in standards or samples, which leads to the formation of a capture antibody - antigen - signal antibody complex, also referred to as a “sandwich”.
During a 2-hour incubation period with shaking immuno-complex is immobilized to the reactive surface of streptavidin coated test tubes. Reaction mixture is then discarded, test tubes washed exhaustively, and the radioactivity is measured in a gamma counter.
The concentration of antigen is directly proportional to the radioactivity measured in test tubes. By constructing a calibration curve plotting binding values against a series of calibrators containing known amount of PSA, the unknown concentration of PSA in patient samples can determined.
上海玉博生物技術有限公司在為生命科學領域提供豐富的產品與信息資源方面處于****地位，公司提供的產品涵蓋了二十多個國家近五十萬種產品，而且產品的數量與信息在不斷的增長和更新，公司提供的產品能夠使生命科學工作者加快對生物化學，分子生物學，細胞生物學以及蛋白質組學研究的認知，以及分子診斷和臨床醫學領域的應用。

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