Markers ideal

Here tQ is the elution time of the marker (ideal, non-retained probe) VL and VQ are the volumes of the two phases within the column. 

Of the four markers just mentioned, the expression of P-selectin on the activated platelets is the most widely studied. However, CD62P may not be the ideal marker for detection of circulating degranulated platelets, because they may rapidly lose their surface P-selectin but yet may continue to function. The decrease in the platelet surface expression of the GPIb-IX-V complex (CD42) perhaps represents a more sensitive marker of in vivo platelet activation. Apparently platelet activation related to strenuous exercise is more readily detected using CD42 than other markers (99). 

Most markers of nutrition status are not ideal. They were first used in epidemiologic studies of large populations and, when applied to individuals, lack specificity and sensitivity. 

In sum, this is how ideal indicators of taxa behave—they intercorrelate in samples where taxon members and nonmembers are mixed, and they do not correlate in pure samples of taxon members or in pure samples of nontaxon members. This behavior of taxon markers is captured by a reduced General Covariance Mixture Theorem (GCMT for the derivation of the theorem... 

GC and GC-MS (see Chapter 2), are ideal for the separation and characterization of individual molecular species. Characterization generally relies on the principle of chemotaxonomy, where the presence of a specific compound or distribution of compounds in the ancient sample is matched with its presence in a contemporary authentic substance. The use of such 6molecular markers is not without its problems, since many compounds are widely distributed in a range of materials, and the composition of ancient samples may have been altered significantly during preparation, use and subsequent burial. Other spectroscopic techniques offer valuable complementary information. For example, infrared (IR) spectroscopy and 13C nuclear magnetic resonance (NMR) spectroscopy have also been applied. 

Polypharmacy. In recent times, polypharmacy is the mle rather than the exception. Patients with complicated and prolonged illnesses may have 20-30 medications in their medical background. Cases of this sort may be of such complexity that even with ideally complete drug and disease marker information, diagnostic success may be elusive. 

Traditional markers of prognosis in cancer have relied on histological features such as tumor size and grade and whether or not local lymph nodes have metastasis. While these histological variables have been widely used over the years in assessing patient outcome, none is ideal. 

The cells are cultured and in vitro restimulated with antigen (here PT) for 12 h to mimic the encounter with the specific antigen in the body. Earlier studies have shown that an in vitro restimulation of mouse spleen lymphocytes with antigen for 4 and 24 h, can be used to study immune response as well as other cellular processes, such as apoptosis, inflammation, and so on (see Chapter 16). Our experiments, however, showed that immune response markers are expressed at later time-points as compared to mouse, and that 12 h of in vitro restimulation is the ideal time-point for the assessment of immune response genes (see Table 17.1) (see Note 1). 

In addition to its content in the glomerular filtrate, the marker is secreted by the renal tubule. Its clearance rate is used to measure renal blood flow but it overestimates the GFR. The aniline derivatives,p-amino hippurate (PAH) or radiolabeled o-iodohippuxan (OIH), represent this group of renal markers. Note that PAH is partly filtered by the glomerular membrane, but molecules that are exclusively excreted by the renal tubules would be ideal for renal blood flow measurements. 

When interpreting these results, it should be taken into consideration that RBC 6-TGN levels can act only as a surrogate marker for the situation in the leukemic blast and may not ideally reflect incorporation of 6-TGN into the DNA and RNA of target cells. This process is likely to be influenced by other thiopurine metabolites such as 6-MMPR and their effects on incorporation and cytotoxicity through inhibition of de novo purine synthesis (101,103). 

Buerge, I.J., Buser, H.R., Kahle, M., Midler, M.D. and Poiger, T. (2000) Ubiquitous occurrence of the artificial sweetener acesulfame in the aquatic environment an ideal chemical marker of domestic wastewater in groundwater. Environ. Sci. Technol.,... 

Similar in principle to this is the use of two different X-ray wavelengths on the same crystal, one near to and the other far from the absorption edge of a marker atom, to give different diffracting powers this is the "ideal isomorphism method advocated by Lipson and Cochran (195 ) and Pepinsky (1956). A comparison of the vector maps for the two wavelengths, or a vector map based on the differences of structure amplitudes for corresponding reflections for the two wavelengths, indicates which peaks are due to the marker atoms. 

The plasmid should have only one cleavage site for a specific restriction endonuclease. This provides only two ends to which the foreign DNA can be attached. Ideally, the single restriction site should be within a gene, so that insertion of the foreign DNA will inactivate the gene (called insertional marker inactivation). 

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