We compare a "second-generation" immunoenzymometric assay (Tandem-E CKMB II) for creatine kinase (EC 2.7.3.2) MB with its electrophoretic (Beckman Paragon system) determination. In the former, two monoclonal antibodies are directed against the B and M subunits. We evaluated 502 samples from 253 patients. Precision, linearity, and analytical recovery for both assays were excellent. The two methods correlated well (r = 0.936). The reference interval for individuals with no suspected cardiac disorder was 0-6.0 micrograms/L; that for non-infarct patients was 0-18.0 micrograms/L. Peak CK-MB values determined by the two assays agreed for 95% of the patients, in terms of exceeding the normal reference interval or not. Diagnostic efficiencies were 86% (Tandem) and 88% (electrophoresis). The immunoenzymometric assay showed no cross reaction with other CK isoenzymes. Both assay methods performed well in detecting CK-MB, although there were some false positives by both methods, as judged from electrocardiographic results. When total CK for the Tandem assay exceeds 2000 U/L, we recommend calculation of a ratio (CK-MB, micrograms/L:total CK, U/L).
This study describes the production of a solid-phase assay (test strip/dipstick test) for putrescine and cadaverine in tuna based on the coupling of an amine oxidase to a peroxidase/dye system. The assay was linear to 75 μM in phosphate buffer, and the minimum detectable concentration was 0.5 μM (<0.1 ppm), corresponding to 0.01 mg% in spiked extracts. Intra- and interassay precisions were <20%. Test strips were stable at 4°C for at least 12 months. Lysine, ornithine, and histidine did not react with the assay, and histamine reacted only minimally. Sixteen fish samples were tested by test strip and the standard AOAC protocol, and results were in good agreement.
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