Analysis in vivo

Belayev L, Pinard E, Nallet H, Seylaz J, Liu Y, Riyamongkol P, Zhao W, Busto R, Ginsberg MD. Albumin therapy of transient focal cerebral ischemia in vivo analysis of dynamic microvascular responses. Stroke 2002 33 1077-1084. 

Enzyme linked electrochemical techniques can be carried out in two basic manners. In the first approach the enzyme is immobilized at the electrode. A second approach is to use a hydrodynamic technique, such as flow injection analysis (FIAEC) or liquid chromatography (LCEC), with the enzyme reaction being either off-line or on-line in a reactor prior to the amperometric detector. Hydrodynamic techniques provide a convenient and efficient method for transporting and mixing the substrate and enzyme, subsequent transport of product to the electrode, and rapid sample turnaround. The kinetics of the enzyme system can also be readily studied using hydrodynamic techniques. Immobilizing the enzyme at the electrode provides a simple system which is amenable to in vivo analysis. 

To improve the selectivity of chronoamperometric in vivo analysis, a differential measurement ta hnique has been employed Instead of a single potential pulse, the potential is alternately pulsed to two different potentials giving rise to the name double chronoamperometry. This waveform is shown in Fig. 15 B. Because the current contributions of individual electroactive components add linearly to produce the observed current output, the difference in current response at the two potentials is the current due to only those compounds which are oxidized at the higher potential and not oxidized at the lower potential. This system provides two responses, the current due to easily oxidized compounds and the current due to harder to oxidize compounds. This gives greater selectivity than the direct chronoamperometric method. 

Another approach to improve selectivity is to use an enzyme electrode. The enzyme ascorbate oxidase has been used successfully to remove ascorbate as an interference of in vivo voltammetric electrodes 219,320) Ascorbate oxidase converts the ascorbic acid to dehydroascorbate which is not electroactive in the potential region used for in vivo analysis. 

In the first two contributions electroanalytical techniques are described for application in bioanalysis and medicine. The increasing interest in this field is mainly due to the excellent selectivities and detection limits. In addition, the possibilities of miniaturization allow the development of in vivo analysis. 

Mattson S, Christoffersson JO, Jonson R, et al. 1987. X-ray fluorescence technique for in vivo analysis of "natural" and administered trace elements. In Elis, Yasumuru, Morgan, eds. In vivo body composition studies. New York, NY Brookhaven National Laboratory, The Institute of Physical Sciences in Medicine. 

It is therefore important to bear in mind the dependency of the carotenoid spectrum upon properties of the environment for in vivo analysis, which is based on the application of optical spectroscopies. This approach is often the only way to study the composition, structure, and biological functions of carotenoids. Spectral sensitivity of xanthophylls to the medium could be a property to use for gaining vital information on their binding sites and dynamics. The next sections will provide a brief introduction to the structure of the environment with which photosynthetic xanthophylls interact—light harvesting antenna complexes (LHC). 

Klinker CC, Bowser MT (2007) 4-Fluoro-7-nitro-2, 1, 3-benzoxadiazole as a fluorogenic labeling reagent for the in vivo analysis of amino acid neurotransmitters using online microdialysis-capillary electrophoresis. Anal Chem 79 8747-8754... 

LeCluyse. In vitro and in vivo analysis of the mechanism of absorption enhancement by palmitoylcamitine.,... 

Weng, Q.-P., Kozlowski, M., Belham, C., Zhang, A., Comb, M.J., and Avruch, J. (1998). Regulation of the p70 S6 kinase by phosphorylation in vivo Analysis using site-specific anti-phosphopeptide antibodies. J. Biol. Chem. 273, 16621-16629. 

K.V. Gobi, Y. Sato, and F. Mizutani, Mediatorless superoxide dismutase sensors using cytochrome c-modified electrodes xanthine oxidase incorporated polyion complex membrane for enhanced activity and in-vivo analysis. Electroanalysis 13, 397-403 (2001). 

For plasma and blood experiments, LC effluent was directed to waste for the first 1 min. Conventional blood analysis by drawing 1 mL samples from the saphenous catheter was used to validate SPME results. These samples were subjected to PPT with acetonitrile and the supernatant from centrifugation was analyzed. The SPME probes were also evaluated for pharmacokinetic analysis of diazepam and its metabolites, oxazepam and nordiazepam. Good correlation was obtained for conventional blood drawn from saphenous and cephalic sites of the animals, as shown in Figure 1.48. Although the analytical parameters for the automated study need improvement, the authors cite the study as a first demonstration of SPME technology for in vivo analysis. 

M. Rizzi, M. Baltes, U. Theobald, and M. Reuss, In vivo analysis of metabolic dynamics in Saccharomyces cerevisiae-. II. Mathematical model. Biotechnol. Bioeng. 55, 592 608 (1997). 

Lee YJ, Park SJ, Ciccone SL, Kim CR, Lee SH (2006) An in vivo analysis of MMC-induced DNA damage and its repair. Carcinogenesis 27(3) 446-453 Loehrer PJ, Einhom LH (1984) Drugs five years later. Cisplatin. Ann Intern Med 100(5) 704-713 Li G, Widom J (2004) Nucleosomes facilitate their own invasion. Nat Struct Mol Biol 11 763-769 Liu W, Sun D, Hurley LH (2005) Binding of G-quadruplex interactive agents to distinct G-quadruplexes induces different biological effects in MiaPaca cells. Nucleosides Nucleotides Nucleic Acids 24(10-12) 1801-1815... 

Rubinstein, A., and Rudai, R., In vitro and in vivo analysis of colon specificity of calcium pectinate formulations, Eur. J. Pharm. Biopharm., 41 291-295 (1995). 

Taylor, A.J., Linforth, R.S.T., Harvey, B.A., Blake, B. (2000) Atmospheric pressure chemical ionisation mass spectrometry for in vivo analysis of volatile flavour release. Food Chem. 71 327-338. 

The in vitro system has some limitations and it can be used only as a model to address acquired drug resistance, because cell lines may not accurately reflect the in vivo situation of patients treated with anticancer drugs. In vivo analysis using patient samples to study anti-cancer drug resistance are described in the published literature. Chang and coworkers (64) showed that the gene-expression patterns from mRNA derived from needle biopsies of breast cancer patients treated with the anticancer drug, docetaxel, could be predictive of response to the therapy. 

Gratton, Alain. 1996. "In Vivo Analysis of the Role of Dopamine in Stimulant and Opiate Self-Administration." Journal of Psychiatry and Neuroscience 21 264-79. 

Interest in microelectrodes, in vivo analysis, and carbon-reinforced structural materials has stimulated research on the electrochemical behavior of carbon fibers. Such fibers have diameters ranging from a few micrometers to about 60 pm, with the majority in the range of 5-15 pm. Although carbon fibers have a wide variety of structures and properties and are often less well characterized than GC or graphite, they have been used successfully in several important electroanalytical experiments. 

The effects of mild ECP on carbon fibers appear to be quite similar to that on macro GC electrodes. Anodization forms surface oxides and eventually a graphite oxide film. The oxide layer or film preferentially adsorbs or ion exchanges cations. In the case of in vivo analysis, this leads to enhanced sensitivity for cationic dopamine over the ascorbate anion [5,6,54], There does not appear to be a standard procedure for mild ECP, but most workers alter the process to improve performance for a particular analytical target. 

Rosebrough S.F., and D.F. Hartley. 1996. Biochemical modification of streptavidin and avidin in vitro and in vivo analysis. 

---