Purpose-In this study, we introduce a methodology for preparing 18 F-labeled Affibody protein, specifically 18 F-Anti-HER2 dimeric Affibody (14 kDa), for in vivo imaging of HER2neu with positron emission tomography (PET). Conclusion-Site-specific 18 F-labeled Affibody against HER2 has been synthesized via chemoselective oxime formation between an aminooxy-functionalized Affibody and 18 Ffluorobenzaldehyde. The results have implications for radiolabeling of other affibodies and macromolecules and should also be important for advancing Affibody imaging with PET.
Procedures-We
Attachment of metal ions to organic molecules in secondary ion mass spectrometry (SIMS) represents a new ionization technique. The phenomenon is general with regard to both the metal (alkali, transition, and noble metals) and the organic (polar and nonpolar compounds). Metals may be present in the free form or as their salts. The process allows for multiple checks on molecular weights and has the advantage that the quasi-molecular ions can be shifted out of regions of the spectrum which are subject to interferences. Fragmentation patterns are obtained and as in other mass spectrometric techniques they can be interpreted to provide molecular structures. The extent of fragmentation varies with the cationizing agent and conditions. The ability to attach a distinctive metal atom, rather than the ubiquitous H atom, as is done when ionizing by protonation, represents an important analytical advantage. Competition studies show that completed d-shell ions such as Cu+ and Ag+ are more effective at cationization than are Pd+ and Pt+, for example. The fragmentation reactions which occur in SIMS correspond to those observed when protonated molecules are mass analyzed and subjected to collision-induced dissociation. These data, together with correspondences between SIMS and electron impact mass spectra, provide strong evidence that the SIMS spectrum arises in large measure from the fragmentation of a single precursor cationized molecule. Some information on the site of cationization is available and there is evidence for bonding in some cases and bonding or simple electrostatic interactions in others. The phenomena observed in SIMS show marked phenomenological parallels with other ionization methods, specifically, field desorption, plasma desorption, laser desorption, and electrohydrodynamic ionization. The unique feature of SIMS is the attachment of metals other than the alkalis. As an indication of the types of studies now possible, results are presented in which a binary alloy is analyzed by examination of organometallic adducts.
The recycling of water coproduced during in situ bitumen production is one of the primary operating challenges for steam assisted gravity drainage (SAGD) operations in oil sand reserves. Produced water that is either recycled for steam production or disposed of may be subject to different water quality requirements for the purposes of plant operations or environmental regulations. The organic components dissolved and suspended in the produced water are a fingerprint of the bitumen-in-place, the processing conditions utilized during production, and the chemicals used by operators during operations. Analysis of SAGD produced water using two-dimensional gas chromatography coupled with electron ionization and time-of-flight mass spectrometry (2DGC-TOFMS) showed a wide variety of organic constituents within the water sample. Compounds ranging from C6 to C18 straight chain and branched aliphatics to more polar, water-soluble, oxygen-and sulfur-heteroatomic species were tentatively identified. Methyl-and ethyl-phenols were prevalent constituents eluting in the heteroatomic region of the chromatographic contour plot. Sample extraction conditions that enhanced partitioning of polar organic species resulted in a significantly larger amount of compounds being detected by this approach. These results show how this method is complementary to more widely used analytical techniques, which cannot provide a comprehensive view of the broad range of compounds within oilfield produced water using a single method.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.