| slovo | definícia |
counterscreening
(gcide) | Screening \Screen"ing\ (skr[=e]n"[i^]ng), n.
the process of examining or testing objects methodically to
find those having desirable properties. See screen[3].
Note: In the pharmaceutical industry, pharmaceutical
screening involves testing a large number of samples of
substances to find those having desirable
pharmacological activity; those samples which have the
property sought are called active or positive in the
screen. The substances tested may be pure compounds
with known structure, mixtures of pure compounds, or
complex mixtures obtained by extraction from living
organisms. There are often additional sets of test
performed on active samples, called
counterscreening to eliminate those samples that may also
possess undesirable properties. In the case of screening
of mixtures from living organisms, a type of
counterscreening called dereplication is usually
performed, to determine if the active sample contains a
known compound which has previously been studied.
[PJC] |
counterscreening
(gcide) | Dereplication \De`rep*li*ca"tion\, n. (Biochem.)
the process of testing samples of mixtures which are active
in a screening process, so as to recognize and eliminate from
consideration those active substances already studied; -- a
stage subsequent to the preliminary screening in the process
of discovery of new pharmacologically active substances in
mixtures of natural products; -- also called
counterscreening. See screening.
Note: In the process of pharmaceutical screening (testing a
large number of substances to find those having
desirable pharmacological activity), the testing of
samples of substances extracted from living organisms
(plants, microorganisms, etc.) often detects substances
already detected in prior screening. Such "known" or
"replicate" activities must be recognized at an early
stage to avoid duplicating previous efforts at
purification and structural identification. The process
of testing an sample which is active in a primary
screen, to determine if the activity is due to a
previously known substance, is called dereplication or
counterscreening.
[PJC] |
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