Second generation diagnostics

TEXAPHYRIN CONJUGATES. PROGRESS TOWARDS SECOND GENERATION DIAGNOSTIC AND THERAPEUTIC AGENTS... 

An unmunoradiometric assay for CA 125 was first developed and manufactured by Centocor, Inc, now Fujirebio Diagnostics. A second generation assay (CA 125II) uses a monoclonal antibody, Mil, as the capture and OC 125 as the conjugate. This assay has been approved by the FDA for the quantitative measurement of CA 125 in serum of women with primary epithelial invasive ovarian cancer. 

A scientific breakthrough in order to design USCAs on demand can be seen in the third generation (Myomap, Quantison, BiSphere and Sonavist). Compared to the more or less free bubbles of the first and second generations, the novel type of USCAs consist of encapsulated microbubbles with a shell formed by a biopolymer (like human albumin) and/or a biocompatible synthetic polymer (like copolymers of poly-lactide and polyglycolide or derivatives of polycyanoacrylate). In addition to the prolongation of the lifetime in the blood stream, these polymer-stabilized microbubbles can be manufactured to fulfill certain needs, and to interact with diagnostic ultrasound in a defined and optimal manner. 

Aldea G, Gutierrez H, Nunzi JM, Chitanu GC, Sylla M, Simionescu BC. 2007. Second harmonic generation diagnostic of layer by layer deposition from Disperse Red 1 functionalized maleic anhydride copol5mer. Opt Mater 29 1640 1646. 

Fig. 11.16. Representation of three tandem mass spectrometry (MS/MS) scan modes illustrated for a triple quadrupole instrument configuration. The top panel shows the attributes of the popular and prevalent product ion CID experiment. The first mass filter is held at a constant m/z value transmitting only ions of a single mlz value into the collision region. Conversion of a portion of translational energy into internal energy in the collision event results in excitation of the mass-selected ions, followed by unimolecular dissociation. The spectrum of product ions is recorded by scanning the second mass filter (commonly referred to as Q3 ). The center panel illustrates the precursor ion CID experiment. Ions of all mlz values are transmitted sequentially into the collision region as the first analyzer (Ql) is scanned. Only dissociation processes that generate product ions of a specific mlz ratio are transmitted by Q3 to the detector. The lower panel shows the constant neutral loss CID experiment. Both mass analyzers are scanned simultaneously, at the same rate, and at a constant mlz offset. The mlz offset is selected on the basis of known neutral elimination products (e.g., H20, NH3, CH3COOH, etc.) that may be particularly diagnostic of one or more compound classes that may be present in a sample mixture. The utility of the two compound class-specific scans (precursor ion and neutral loss) is illustrated in Fig. 11.17.

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