Detection of activities

Nakano, M. (1998). Detection of active oxygen species in biological systems. Cell. Mol. Neurobiol. 18 565-579. 

Suzuki, N., etal. (1991). Studies on the chemiluminescent detection of active oxygen species 9-acridone-2-sulfonic acid, a specific probe for superoxide. Agric. Biol. Chem. 55 1561-1564. 

Suzuki, N., et al. (1991). Chemiluminescent detection of active oxygen species, singlet molecular oxygen and superoxide, using Cypridina luciferin analogs. Nippon Suisan Gakkaishi 57 1711-1715. 

A fairly efficient method of selective detection of active forms of oxygen by means of sensors is the preliminary separation of their mixture with the aid of filters designed for the purpose, filters that vigorously de-excite this or that form of oxygen. It has been mentioned in Section 5.4 that freshly atomized films of Ag efficiently absorb O-atoms from the gaseous phase, mildly de-excite 02 molecules. To de-excite the singlet oxygen molecules proper, use should be made of filters with... 

FIA has also found wide application in pharmaceutical analysis.214,215 Direct UV detection of active ingredients is the most popular pharmaceutical analysis application of FIA. For single component analysis of samples with little matrix interference such as dissolution and content uniformity of conventional dosage forms, many pharmaceutical chemists simply replace a column with suitable tubing between the injector and the detector to run FIA on standard HPLC instrumentation. When direct UV detection offers inadequate selectivity, simple online reaction schemes with more specific reagents including chemical, photochemical, and enzymatic reactions of derivatization are applied for flow injection determination of pharmaceuticals.216... 

All of the described procedures use emulsified substrate. Although the p-nitrophenyl laurate assay cocktail is stable for 3 days at 4°C, the emulsified olive oil substrates (or other triacylglycerol-based substrate systems) should be made fresh daily and rehomogenized periodically and when separation is visually evident. Use of day-old emulsion substrate will yield increased blank values for titratable acidity, and this effectively compromises the limit of detection of activity. Emulsified substrates should be in liquid form at common assay conditions (20° to 50°C), and partially solidified substrates (those rich in long-chain saturated fatty acids) will cause interfacial irregularities and confound the assessment of lipases in ways that cannot be accounted for. 

Holzwarth, A. and Maier, W.F. (2000) Catalytic phenomena in combinatorial libraries of heterogeneous catalysts detection of activation and deactivation by emissivity-corrected IR thermography. Platinum Met. Rev., 44, 16. 

Natural water (pH 6.0) and sediment (organic content 36%) used in this study were fortified with both the insecticides and subsequently analyzed by the described methods. No response that interfered with the detection of active ingredients was found in any of the untreated controls during incubation. The recoveries for water were 93 4% at 400 ppb and 97 7% at 20 ppb for sediment they were 86 6% and 91 9%, respectively, at the same fortification levels. The minimum detection limit (MDL) for both insecticides was 0.1 ppb in water and 10 ppb in sediment (as sampled). 

Micro structured wells (2 mm x 2 mm x 0.2 mm) on the catalyst quartz wafer were manufactured by sandblasting with alumina powder through steel masks [7]. Each well was filled with mg catalyst. This 16 x 16 array of micro reactors was supplied with reagents by a micro fabricated gas distribution wafer, which also acted as a pressure restriction. The products were trapped on an absorbent plate by chemical reaction, condensation or absorption. The absorbent array was removed from the reactor and sprayed with dye solution to obtain a color reaction, which was then used for the detection of active catalysts by a CCD camera. Alternatively, the analysis was also carried out with a scanning mass spectrometer. The above-described reactor configuration was used for the primary screening of the oxidative dehydrogenation of ethane to ethylene, the selective oxidation of ethane to acetic acid, and the selective ammonoxidation of propane to acrylonitrile. 

It is now well established that a variety of organic molecules such as polynuclear aromatic hydrocarbons with low ionization energies act as electron donors with the formation of radical cations when adsorbed on oxide surfaces. Conversely, electron-acceptor molecules with high electron affinity interact with donor sites on oxide surfaces and are converted to anion radicals. These surface species can either be detected by their electronic spectra (90-93, 308-310) or by ESR. The ESR results have recently been reviewed by Flockhart (311). Radical cation-producing substances have only scarcely been applied as poisons in catalytic reactions. Conclusions on the nature of catalytically active sites have preferentially been drawn by qualitative comparison of the surface spin concentration and the catalytic activity as a function of, for example, the pretreatment temperature of the catalyst. Only phenothiazine has been used as a specific poison for the butene-1 isomerization on alumina [Ghorbel et al. (312)). Tetra-cyaonoethylene, on the contrary, has found wide application as a poison during catalytic reactions for the detection of active sites with basic or electron-donor character. This is probably due to the lack of other suitable acidic probe or poison molecules. 

Despite extensive research, identification of apoptotic cells remains an important unresolved issue. Apoptosis can be recognized by characteristic morphological features, which are difficult to be found in the heart. Furthermore, morphology alone does not enable recognition of cells early in the apoptotic pathway. Detection of activated caspases appears to be a reasonable way to detect apoptotic cells, given the central role of caspases in the process of apoptosis. It must be kept in mind, however, that caspases may contribute to necrotic cell death [80, 81] and caspase-independent apoptosis does occur [80]. 

Immunohistochemistry, on the other hand, enables identification of activated caspases or their cleaved products in fixed archival tissue sections. This technique allows identification of cell(s) undergoing caspase activation, as well as analysis of the distribution of cell(s) in the tissue. Specific antibodies to various caspases are now commercially available, the most frequently studied being caspase-3. Studies in various human tissues and cells have shown that immunohistochemical detection of activated caspase-3 is a useful tool for identifying apoptotic cells in archival material, even before all of the morphological features of apoptosis occur [84-86]. Several target proteins cleaved by caspases can also be detected by immunohistochemistry for example PARP [87], actin [88, 89], and lamin B [90]. 

V. METALLO-1,2-ENEDITHIOLATES AND A NEW METHOD FOR THE DETECTION OF ACTIVATED PHOSPHATES... 

Schmidt, P. M., Lehmann, C., Matthes, E., and Bier, F. F. (2002). Detection of activity of telomerase in tumor cells using fiber optical biosensors. Biosens. Bioelectron. 17 1081-1087. 

AntAMS C, SHATTIL SJ. Ugomunok cal detection of activated platdets in clinical disorders. Thromb Haemost <5 467-473,1991. 

Shattil S J, Cunningham M, Hoxie JA. Detection of activated platelets in whole blood using activation-dependent monoclonal antibodies and flow cytometry. Blood 1987 70 307-315. 

When using BrMAC, postcolumn hydrolysis of separated PG esters is neccessary for on-line detection of the fluorophore, resulting in detection limits of about 10 fmol. Hydrazone or amide derivatives are also suitable for fluorescence detection as well as 3-bro-momethyl-6,7-dimethoxy-l-methyl-2(l//) quinoxali-none (YMC Pack C8) or 9-anthroyldiazomethane (ADAM) characterized by its low stability (Nucleosil ODS silica). Electrochemical detection of active com-... 

Gfeller, K. Y., Nugaeva, N., and Hegner, M. (2005). Micromechanical oscillators as rapid biosensor for the detection of active growth of Escherichia coli. Biosens. Bioelectron. 21,528-533. 

The physical format of the compound library must also be determined before starting an HTOS experiment. The decision as to whether to synthesize mixtures of compounds or discrete chemical entities is related to the purpose for synthesizing the library. Libraries of mixtures allow for the screening of more compounds than discrete libraries, but large numbers of compounds per pool can adversely affect the detection of active compounds. The testing of mixtures also introduces the possibility of signal-to-noise ratio deterioration or the introduction of false positives (30). Within the pharmaceutical industry today, the trend is to produce smaller libraries of well-defined (discrete) compounds using parallel synthesis techniques (31). 

---